D E S C R I P T I O N

METHOD OF FORMING PATTERN AND ACTINIC-RAY- OR RADIATION-SENSITIVE

RESIN COMPOSITION FOR USE IN THE METHOD

Cross-Reference to Related Applications

This application is based upon and claims the benefit of priority from prior Japanese Patent

Application No. 2012-144765, filed June 27, 2012, the entire contents of which are incorporated herein by reference.

Technical Field

The present invention relates to a method of forming a pattern and an actinic-ray- or radiation- sensitive resin composition for use in the method. More particularly, the present invention relates to a method of forming a negative pattern, which method finds appropriate application in a semiconductor production process for an IC or the like, a circuit o-a.nd„p „o_du ±i.o.n„p _0-C.e.s.s„f-O ™a„Li ui.d_cr-ys--t.al-, a- thermal head or the like and other photofabrication lithography processes, and also relates to an actinic- ray- or radiation-sensitive resin composition for use in the method. Further, the present invention relates to a process for manufacturing an electronic device, which process comprises the above pattern forming method, and an electronic device manufactured by the process. Still further, the present invention relates to an actinic-ray- or radiation-sensitive film

comprising the actinic-ray- or radiation-sensitive resin composition.

Background Art

Since the development of the resist for a KrF excimer laser (248 nm) , a pattern forming method based on chemical amplification has been employed in order to compensate for any sensitivity decrease caused by light absorption. For example, in a positive chemical amplification method, the photoacid generator contained in exposed areas is first decomposed upon exposure to light to thereby generate an acid. In the stage of the bake after the exposure (Post-Exposure Bake: PEB) or the like, alkali-insoluble groups contained in the actinic-ray- or radiation-sensitive resin composition are converted to alkali-soluble groups by virtue of the catalytic action of the generated acid. Thereafter, development is performed with the use of, for example, an alkali solution. Thus, the exposed areas are removed, thereby obtaining a desired pattern.

For use in the above method, various alkali developers have been proposed. For example, an aqueous alkali developer containing 2.38 mass% TMAH (aqueous solution of tetramethylammonium hydroxide) is

universally used as an alkali developer.

Moreover, the shortening of the wavelength of exposure light sources and the realization of high numerical apertures (high NA) for projector lenses have been advanced in order to cope with the miniaturization of semiconductor elements. To now, an exposure unit using an ArF excimer laser of 193 nm wavelength as a light source has been developed. Further, a method

(known as a liquid-immersion method) in which the space between a projector lens and a sample is filled with a liquid of high refractive index (hereinafter also referred to as an "immersion liquid") has been proposed as a technology for enhancing the resolving power.

Still further, an EUV lithography in which the exposure is carried out using an ultraviolet of further shorter wavelength (13.5 nm) has been proposed.

In this current situation, various formulations have been proposed as positive resist compositions

(see, for example, patent references 1 and 2).

Moreover, not only the currently mainstream positive type but also the method of forming a pattern with a negative developer, namely, a developer comprising an organic solvent is being developed (see, for example, patent references 3. and 4) . This reflects the

situation in which in the production of semiconductor elements and the like, while there is a demand for the formation of patterns with various shapes, such as a line, a trench and a hole, there exist patterns whose formation is difficult with the use of current positive resists . However, discovering an appropriate combination of used resin, photoacid generator, basic compound, additive, solvent, etc. from the viewpoint of

comprehensive performance as a resist is extremely difficult, and the current situation is that any combination is still unsatisfactory. For example, there is a demand for the development of a resist composition that excels in exposure latitude

(hereinafter also referred to as EL) , line width roughness (hereinafter also referred to as LWR) and. focus latitude (hereinafter also referred to as DOF) , and ensures less occurrence of pattern collapse.

[Citation List]

[Patent Literature]

Patent reference 1: Jpn. Pat. Appln. KOKAI

Publication No. (hereinafter referred to as JP-A-) 2009-007327,

Patent reference 2: JP-A-2009-169228 ,

Paj nt_r_eference 3: JP-A-2008-29297_5_.__and_

Patent reference 4: JP-A-2009-164958.

Disclosure of Invention

It is an object of the present invention to provide a method of forming a pattern, which method excels in exposure latitude, line width roughness and focus latitude and ensures less occurrence of pattern collapse. It is another object of the present

invention to provide an actinic-ray- or radiation-sensitive resin composition for use in the method.

The present invention is, for example, as recited belo .

[ 1 ] A method of forming a pattern, comprising: forming a film comprising an actinic-ray- or radiation-sensitive resin composition comprising:

a resin (A) comprising any of repeating units of general formula (I) below, which resin when acted on by an acid, decreases its solubility in a developer comprising an organic solvent, and

a compound (B) expressed by any of general formulae (B-l) to (B-3) below, which compound when exposed to actinic rays or radiation, generates an acid;

exposing the film to actinic rays or radiation; and

developing the exposed film with a developer comprising an organic solvent to thereby obtain a negative pattern,

in general formula (I)

R Q represents a hydrogen atom or an alkyl group, and

each of to R3 independently represents an alkyl group or a cycloalkyl group, provided that at least one of R]_ to R is a cycloalkyl group,

in general formula (B-1)

A ⁺ represents a sulfonium cation or an iodonium cation,

m is 0 or 1,

n is an integer of 1 to 3,

Xbl represents -0-, -OCO-, -COO-, -OSO2- or -SO2-O-, and

Rk2 represents a substituent having 6 or more carbon atoms,

in general formula (B-2)

A ⁺ represents a sulfonium cation or an iodonium cation, and

Qbl represents a group containing a lactone structure, a group containing a sultone structure or group containing a cyclocarbonate structure, and in general formula (B-3)

A ⁺ represents a sulfonium cation or an iodonium cation,

Lj-,2 represents an alkylene group,

X) ₃ 2 represents -0-, -0C0- or -C00-, and

Qj-,2 represents a cycloalkyl group or a group containing an aromatic ring.

[2] The method according to item [1], wherein the resin (A) further comprises any of repeating units of general formula (II) below,

in general formula (II)

RQ represents a hydrogen atom or an alkyl group, R represents an alkyl group, and

Y represents a cyclic hydrocarbon structure formed with a carbon atom to which R4 is bonded.

[3] The method according to item [1] or [2], wherein the actinic-ray- or radiation-sensitive resin composition further comprises a basic compound or ammonium salt compound that when exposed to actinic rays or radiation, lowers its basicity.

[4] The method according to any of items [1] to [3], wherein A ^4" in general formulae (B-l) to (B-3) above is expressed- by general formula ( Z I - 3 ) or (ZI-4 below,

in general formula ( Z I - 3 )

each of R_ _c to R5 _C independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an ary1 group, an aJ koxy qroup, an a ryloxy—g oup-, an alkoxycarbonyl group, an alkylcarbonyloxy group, a cycloalkylcarbonyloxy group, a halogen atom, a hydroxyl group, a nitro group, an alkylthio group or an arylthio group;

each of Rg _c and R7 _C independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, a cyano group or an aryl group; and

each of Rx and Ry independently represents an alkyl group, a cycloalkyl group, a 2-oxoalkyl group, a 2-oxocycloalkyl group, an alkoxycarbonylalkyl group, an allyl group or a vinyl group,

^' provided that any two or more of R ^ _Q to R5 _C , R5 _C and R6 _C , Rg _c and R7 _C , R5 _C and Rx, and Rx and Ry may be bonded to each other to thereby form a ring structure in which an oxygen atom, a sulfur atom, a ketone group, an ester bond and/or an amide bond may be contained; and

in general formula (ZI-4)

R_3 represents a hydrogen atom, a fluorine atom, a hydroxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group or a group containing a cycloalkyl group;

R]_4, each independently when there are a plurality of R14S, represents a hydroxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, an alkylsulfonyl group, a cycloalkylsulfonyl group or a group■ containing a cycloalkyl group;

each of R15S independently represents an alkyl group, a cycloalkyl group or a naphthyl group, provided that two R15S may be bonded to each other to thereby form a ring in cooperation with a sulfur atom to which R^5 is bonded, which ring may contain an oxygen atom, a sulfur atom, a ketone group, an ester bond and/or an amide bond;

t is an integer of 0 to 2·; and

r is an integer of 0 to 8.

[5] The method according to any of items [1] to [4], wherein the developer comprises at least one organic solvent selected from the group consisting of a ketone solvent, an ester solvent, an alcohol solvent, an amide solvent and an ether solvent.

[6] A process for manufacturing an electronic device, comprising the method according to any of items [1] to [5] .

[7] An electronic device manufactured by the process of item 6.

[8] An actinic-ray- or radiation-sensitive resin composition comprising:

a resin (A) comprising any of repeating units of general formula (I) below and any of repeating units of general formula (II) below, which resin when acted on by an acid, decreases its solubility in a developer comprising an organic solvent, and

a compound (B) expressed by any of general formulae (B-l) to (B-3) below, which compound when exposed to actinic rays or radiation, generates an acid;

in general formula (I)

RQ represents a hydrogen atom or an alkyl group, and each of R _ to R3 independently represents an alkyl group or a cycloalkyl group, provided that at least one of R-]_ to R3 is a cycloalkyl group,

(ii)

in general formula (II)

RQ represents a hydrogen atom or an alkyl group, R4 represents an alkyl group, and

Y represents a cyclic hydrocarbon structure formed a carbon atom to which R4 is bonded,

in general formula (B-1)

A ⁺ represents a sulfonium cation or an iodonium cation,

m is 0 or 1,

n is an integer of 1 to 3,

Xbl represents -0- , -OCO-, -COO-, -OSO2 - or - SO2-O-, and

¾ _> 2 represents a substituent having 6 or more carbon atoms,

in general formula (B-2)

A ⁺ represents a sulfonium cation or an iodonium cation, and

¾ _> 1 represents a group containing a lactone structure, a group containing a sultone structure or a group containing a cyclocarbonate structure, and

A © ΘO _Λ -SSL >-L _b2 -X _b2 - ^Q _b2 ( ^B-3 )

i i F

O O

in general formula (B-3)

A ⁺ represents a sulfonium cation or an iodonium cation,

¾ _> 2 represents an alkylene group,

Xj-,2 represents -0-, -OCO-, or -COO-, and

(¾2 represents a cycloalkyl group or a group containing an aromatic ring.

[9] The actinic-ray- or radiation-sensitive resin composition according to item [8], further comprising a basic compound or ammonium salt compound that when exposed to actinic rays or radiation, lowers its basicity .

[10] The actinic-ray- or radiation-sensitive resin composition according to item [8] or [9], wherein A+ in general formulae (B-l) to (B-3) above is

expressed by general formula (ZI-3) or (ZI-4) below,

in general formula (ZI-3)

each of R; _j _ _c to R5 _C independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an alkylcarbonyloxy group, a cycloalkylcarbonyloxy group, a halogen atom, a hydroxyl group, a nitro group, an alkylthio group or an arylthio group;

each of R _C and R7 _C independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, a cyano group or an aryl group; and

each of Rx and Ry independently represents an alkyl group, a cycloalkyl group, a 2-oxoalkyl group, a 2-oxocycloalkyl group, an alkoxycarbonylalkyl group, .an

^' allyl group or a vinyl group,

provided that any two or more of R^ _c to s _c , R5 _C and Rg _c , Rg _c and R7 _C , R5 _C and Rx, and Rx and Ry may be bonded to each other to thereby form a ring structure in which an oxygen atom, a sulfur atom, a ketone group, an ester bond and/or an amide bond may be contained; and

in general formula (ZI-4)

R_3 represents a hydrogen atom, a fluorine atom, a hydroxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group or a group containing a cycloalkyl group;

R]_4, each independently when there are a plurality of R_4S, represents a hydroxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, an alkylsulfonyl group, a cycloalkylsulfonyl group or a group containing a cycloalkyl group;

each of 15S independently represents an alkyl group, a cycloalkyl group or a naphthyl group, provided that two R15S may be bonded to each other to thereby form a ring in cooperation with a sulfur atom to which R]_5 is bonded, which ring may contain an oxygen atom, a sulfur atom, a ketone group, an ester bond and/or an amide bond;

t is an integer of 0 to 2; and

r is an integer of 0 to 8.

[11] An actinic-ray- or radiation-sensitive film comprising the actinic-ray- or radiation-sensitive resin composition according to any of items [8] to [10] .

The present invention makes it feasible to provide a method of forming a pattern, which method excels in exposure latitude, . line width roughness and focus latitude and ensures less occurrence of pattern

collapse, and to provide an actinic-ray- or radiation- sensitive resin composition for use in the method.

Best Mode for Carrying Out the Invention

Embodiments of the present invention will be described in detail below.

Herein, the groups and atomic groups for which no statement is made as to substitution or nonsubstitution are to be interpreted as including those containing no substituents and also those containing substituents. For example, the "alkyl groups" for which no statement is made as to substitution or nonsubstitution are to be interpreted as including not only the alkyl groups containing no substituents (unsubstituted alkyl groups) but also the alkyl groups containing substituents

(substituted alkyl groups) .

Further, herein, the term "actinic rays" or

"radiation" means, for example, brightline spectra from a mercury lamp, far ultraviolet represented by an excimer laser, X-rays, soft X-rays such as extreme ultraviolet (EUV) light, or electron beams (EB) . The term "light" means actinic rays or radiation.

The term "exposure to light" unless otherwise specified means not only irradiation with light, such as light from a mercury lamp, far ultraviolet, X-rays or EUV light, but also lithography using particle beams, such as electron beams and ion beams.

<Actinic-ray- or radiation-sensitive resin composition>

First, the actinic-ray- or radiation-sensitive resin composition according to the present invention (hereinafter also referred to as the "composition of the present invention" or "resist composition of the present invention") will be described. This resist composition is typically used in the negative

development, namely, development with a developer comprising an organic solvent. That is, the

composition of the present invention is typically a negative resist composition.

The actinic-ray- or radiation-sensitive resin composition of the present invention comprises the f_al.Lo_w.ing [_1_] r_eain (A) ^c_omprl.aing___anyi___Qf___r_ep_e.at_ing units of general formula (I), which resin when acted on by an acid, decreases its solubility in a developer comprising an organic solvent, and [2] compound (B) expressed by any of general formulae (B-l) to (B-3), which compound when exposed to actinic rays or

radiation, generates an acid.

The repeating units of general formula (I) to be described- below are -protected by protective ^groups 'of - high activation energy. The compound (B) expressed by any of general formulae (B-l) to (B-3) to be described below exhibits a high pKa, namely, low acidity.

Deprotection of the repeating units of general formula (I) can be suppressed by combining these, so that any inverted tapering of pattern shape as often experienced in the negative pattern formation can be suppressed. Suppression of any inverted tapering of pattern shape can lead to enhancement of DOF through the elimination of bridging at defocusing and enhancement of LWR, further to suppression of pattern collapse at

decreasing of line width.

Further components that can be incorporated in the composition of the present invention are a solvent [3], a hydrophobic resin [4], a basic compound [5], a surfactant [6] and other additives [7]. The

composition of the present invention can be used in the pattern formation in accordance with, for example, the method to be described hereinafter as "method of forming a pattern."

These components will be described in sequence below .

[1] Resin (A)

The resin (A) is the following resin (hereinafter also referred to as "acid-decomposable resin (A)") comprising any of repeating units of general formula (I), which resin when acted on by an acid, decreases its solubility in a developer comprising an organic solvent. The repeating units that can be incorporated in the resin (A) will be described in sequence below, (a) Repeating unit containing acid-decomposable group

The resin (A) comprises any of repeating units of general formula (I) below as a repeating unit

containing an acid-decomposable group.

In general formula (I) above,

RQ represents a hydrogen atom or an alkyl group. This alkyl group may be linear or branched.

Each of R]_ to R3 independently represents an alkyl group or a cycloalkyl group. This alkyl group may be linear or branched. This cycloalkyl group may be monocyclic or polycyclic. Provided that at least one of R]_ to R3 is a cycloalkyl group.

A substituent may be introduced in the linear or branched alkyl group represented by RQ . A linear or branched alkyl group having 1 to 4 carbon atoms is preferred. As such, there can be mentioned a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group or the like. As the substituent, there can be mentioned a hydroxyl group, a halogen atom (for.

example, a fluorine atom) or the like.

It is preferred for Rg to be a hydrogen atom, a methyl group, a trifluoromethyl group or a

hydroxymethyl group.

Each of the alkyl groups represented by to R3 is preferably one having 1 to 4 carbon atoms, such as methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group o a t-butyl group.

Each of the cycloalkyl groups represented by R\ t R3 is preferably a monocycloalkyl group, such as a cyclopentyl group or a cyclohexyl group, or a

polycycloalkyl group, such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group o an adamantyl group.

Substituents may be introduced in the groups represented by R]_ to R3. As the substituents, there can be mentioned, for example, a hydroxyl group, a halogen atom (for example, a fluorine atom), an alkyl group (1 to 4 carbon atoms), a cycloalkyl group (3 to carbon atoms), an alkoxy group (1 to 4 carbon atoms), carboxyl group, an alkoxycarbonyl group (2 to 6 carbon atoms) and the like. The number of carbon atoms of each of these substituents is preferably up to 8.

Preferred particular examples of the repeating units of general formula (I) are shown below, which however in no way limit the scope of the present invention .

In the particular examples, Rx represents a hydrogen atom, CH3, CF3 or CH2OH. Each of Rxa and Rxb represents an alkyl group having 1 to 4 carbon atoms. Z represents a substituent. When there are a plurality of Z's, they may be identical to or different from each other. In the formulae, p is 0 or a positive integer. Particular examples and preferred examples of the substituents represented by Z are the same as those mentioned above in connection with the groups

represented by R _] _ to R3.

It is preferred for the resin (A) to further comprise any of repeating units of general formula (II) below as a repeating unit containing an acid- decomposable group.

In general formula (II) above,

Rg is as defined above in connection with general formula ( I ) .

R represents an alkyl group, preferably an alkyl group having 1 to 3 carbon atoms. A methyl group or an ethyl group is more preferred. A substituent may be introduced in the alkyl group represented by R4. As preferred substituents , there can be mentioned those set forth above in connection with R^ to R3 in general formula ( I ) .

Y represents a cyclic hydrocarbon structure formed in cooperation with a carbon atom to which R4 is bonded .

The cyclic hydrocarbon structure represented by Y may be monocyclic or polycyclic. A monocyclic

structure is preferred. The monocyclic hydrocarbon structure is preferably a monocyclic hydrocarbon structure having 3 to 8 carbon atoms, more preferably a monocyclic hydrocarbon structure having 5 or 6 carbon atoms. As the polycyclic hydrocarbon structure, there can be mentioned a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, an adamantyl group or the like. A substituent may be introduced in the cyclic hydrocarbon structure represented by Y. As preferred substituents , there can be mentioned those set forth above in connection with R _] _ to R3 in general formula (I).

Preferred particular examples of the repeating units of general formula (II) are shown below, which however in no way limit the scope of the present invention.

In the particular examples, Rx represents a hydrogen atom, CH3, CF3 or CH2OH. R4 is as defined above in connection with general formula (II) . Z represents a substituent. When there are a plurality of Z's, they may be identical to or different from each other. In the formulae, p is 0 or a. positive integer. Particular examples and preferred examples of the substituents represented by Z are the same as those mentioned above in connection with the groups

represented by R^ to R3 -in general formula (I) .

The resin (A) may comprise two or more of the repeating units of general formula (I) above. This is true with respect to the repeating units of general formula (II) above.

When the resin (A) comprises none of the repeating units of general formula (II), the content of repeating unit expressed by general formula (I) in the resin (A), based on all the repeating units of .the resin (A) ., is preferably in the range of 30 to 70 mol%, more

preferably 35 to 65 mol% and most preferably 40 to 60 ,mol%.

When the resin (A) comprises any of the repeating units of . general formula (II), the content of repeating unit expressed by general formula (I) in the resin (A), based on all the repeating units of the resin (A) , is preferably in the range of 5 to 40 mol%, more

preferably 5 to 35 mol% and most preferably 5 to

30 mol%.

When the resin (A) comprises any of the repeating units of general formula (II), the content of repeating unit expressed by general formula (II) in the resin (A) , based on all the repeating units of the resin (A) , is preferably in the range of 10 to 80 mol%, more preferably 15 to 70 mol% and most preferably 20 to 60 mol%.

When the resin (A) comprises any of the repeating units of general formula (II), the molar ratio between repeating unit expressed by general formula (I) and repeating unit expressed by general formula (II) is preferably in the range of 12:1 to 1:3, more preferably 10:1 to 1:1 and most preferably 8:1 to 8:5.

The resin (A) may comprise a repeating unit containing an acid-decomposable group other than the repeating units of general formulae (I) and (II).

As such a repeating unit, there can be mentioned the following. In the formulae, Rx represents a hydrogen atom, CH3 , CF3 or CH2OH.

The content of the sum of repeating units each containing an acid-decomposable group based on all the repeating units of the resin (A) is preferably 20 mol% or more, more preferably 30 m l% or more, further more preferably 45 mol% or more, and most preferably 50 mol% or more.

The content of the sum of repeating units each containing an acid-decomposable group based on all the repeating units of the resin (A) is preferably up to 90 mol%, more preferably up to 85 mol%.

(b) Repeating unit containing lactone structure or sultone structure

The resin (A) may further comprise a repeating unit containing a lactone structure or sultone

structure .

Lactone and sultone structures are not

particularly limited as long as lactone and sultone structures are contained respectively. A 5 to 7- membered ring lactone structure is preferred, and one resulting from the condensation of a 5 to 7-membered ring lactone structure with another cyclic _s ,r_ c_t.ur_e_ effected in a fashion to form a bicyclo structure or spiro structure is also preferred. More preferably, the resin comprises a repeating unit with any of the lactone structures of general formulae (LCl-1) to (LC1- 17) below or sultone structures of general formulae (SLl-1) to (SL1-3) below. The lactone structure or sultone structure may be directly bonded to the

principal chain of the resin. Preferred lactone- structures are those of formulae (LCl-1), (LCl-4), (LCl-5), (LC1-6), (LCl-13), (LCl-14) and (LCl-17).

Lactone structure (LCl-4) is most preferred. Using these specified lactone structures enhances LWR and reduces development defects.

LC1-18 LC1-19 LC1-20 LC1-21 SL1-1 SL1-2 SL1-3

The presence of a substituent (Rb2) on the portion of the lactone or sultone structure is optional. As a preferred substituent (Rb2), there can be mentioned an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 2 to 8 carbon atoms, a carboxyl group, a halogen atom, a hydroxyl group, a cyano group, an acid- decomposable group or the like. Of these, an alkyl group having 1 to 4 carbon atoms,' a cyano group and an acid-decomposable group are more preferred. In the formulae, n.2 is an integer of 0 to 4. When n2 is 2 or greater, the plurality of present substituents (Rb2) may be identical to or different from each other.

Further, the plurality of present substituents (Rb2) may be bonded to each other to thereby form a ring.

The repeating unit having a lactone structure or sultone structure is generally present in the form of optical isomers. Any of the optical isomers may be used. It is both appropriate to use a single type of optical isomer alone and to use a plurality of optical isomers in the form of a mixture. When a single type of optical isomer is mainly used, the optical purity (ee) thereof is preferably 90% or higher, more

preferably 95% ^' or higher.

As the repeating unit having a lactone structure or sultone structure, it is preferred for the resin (A) to contain any of the repeating units represented by general formula (All) below.

In general formula (All),

Ron represents a hydrogen atom, a halogen atom or an optionally substituted alkyl group (preferably having 1 to 4 carbon atoms) .

As preferred substituents that may be introduced in the alkyl group represented by Rbn, there can be mentioned a hydroxyl group and a halogen atom. As the halogen atom represented by Rbn, there can be mentioned a fluorine atom, a chlorine atom, a bromine atom or an iodine atom. Rbn is preferably a hydrogen atom, a methyl group, a hydroxymethyl group or a

trifluoromethyl group. A hydrogen atom and a methyl group are especially preferred.

Ab represents a single bond, an alkylene group, a bivalent connecting group with a mono- or

polycycloalkyl structure, an ether bond, an ester bond, a carbonyl group, or a bivalent connecting group resulting from combination of these. Ab is preferably a single bond or any of the bivalent connecting groups of the formula -Ab^-CC^-.

Ab _] _ represents a linear or branched alkylene group or a mono- or polycycloalkylene group, preferably a methylene group, an ethylene group, a cyclohexylene group, an adamantylene group or a norbornylene group.

V represents a group with a lactone structure or sultone structure, for example, a group with any of the structures of general formulae (LCl-1) to (LCl-17) and (SLl-1) to (SL1-3) above.

When the resin (A) comprises a repeating unit with a lactone structure or sultone structure, the content of repeating unit with a lactone structure or sultone structure based on all the repeating units of the resin (A) is preferably in the range of 0.5 to 80 mol%, more preferably 1 to 65 mol%, further more preferably 5 to 60 mol%, especially further more preferably 3 to

50 mol%, and most preferably 10 to 50 mol%.

Any one of the repeating units each with a lactone structure or sultone structure may be used alone, or two or more thereof may be used in combination.

Particular examples of the repeating units each with a lactone structure or sultone structure are shown below, which in no way limit the scope of the present invention .

In the following particular examples, Rx

represents H, CH3, CH2OH or CF3.

31

(c) Repeating unit containing hydroxyl group or cyano group

The resin (A) may further comprise a repeating unit containing a hydroxyl . group or a cyano group.

This would realize enhancements of the adhesion to substrate and developer affinity. The repeating unit containing a hydroxyl group or a cyano group is preferably a repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group, which repeating unit preferably contains no acid-decomposable, group.

It is preferred for the repeating unit with an alicyclic hydrocarbon structure substituted with a hydroxyl group or cyano group to be different from the repeating units of general formula (All) above.

In the alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group, the alicyclic hydrocarbon structure is preferably comprised of an adamantyl group, a diamantyl group or a norbornane group. The alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group is preferably any of the partial structures of general formulae

(Vila) to (Vlld) below.

(Vila) (Vflb) (VHc) (VHd)

In general formulae (Vila) to (VIIc) ,

each of R2C to R4C independently represents a hydrogen atom, a hydroxyl group or a cyano group, provided that at least one of R2C to R4C represents a hydroxyl group or a cyano group. Preferably, one or two of R2C to R4C are hydroxyl groups and the remainder is a hydrogen atom. In general formula (Vila) , more preferably, two of R2C to R4C are hydroxyl groups and the remainder is a hydrogen atom.

As the repeating units with any of the partial structures of general formulae (Vila) to (Vlld) , there can be mentioned the repeating units of general formulae (Alia) to (Alld) below.

(Allb)

In general formulae (Alia) to (Alld) ,

R _j c represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.

R2C to R4C are as defined above in connection with general formulae (Vila) to (VIIc) .

■It is optional for the resin (A) to comprise the repeating unit containing a hydroxyl group or a cyano group. When the repeating unit containing a hydroxyl group or a cyano group is contained in the resin (A) , the content thereof, based on all the repeating units of resin (A) , is preferably in the range of 1 to

40 mol%, more preferably 3 to 30 mol% and further more preferably 5 to 25 mol%.

Specific examples of the repeating units each containing a hydroxyl group or a cyano group are shown below, which however in no way limit the scope- of the present invention.

(d) . Repeating unit containing acid group

The resin (A) may comprise a repeating unit containing an acid group. As the acid group, there can be mentioned a carboxyl group, a sulfonamido group, a sulfonylimido group, a bisulfonylimido group or an aliphatic alcohol substituted at its a-position with an electron-withdrawing group (for example, a

hexafluoroisopropanol group) . It is preferred to comprise a repeating unit containing a carboxyl group.

The incorporation of the repeating unit containing an acid group would increase the resolution in, for example, contact hole usage. The repeating unit containing an acid group is preferably any of a

repeating unit wherein the acid group is directly bonded to the principal chain of a resin such as a repeating unit of acrylic acid or methacrylic acid, a repeating unit wherein the acid group is bonded via a connecting group to the principal chain of a resin and a repeating unit wherein the acid group is introduced in a terminal of a polymer chain by the use of a chain transfer agent or polymerization initiator containing the acid group in the stage of polymerization. The connecting group may have a cyclohydrocarbon structure of a single ring or multiple rings. The repeating unit of acrylic acid or methacrylic acid is especially preferred .

It is optional for the resin (A) to contain the repeating unit containing an acid group. When the repeating unit containing an acid group is contained in the resin (A) , the content thereof based on all the repeating units of the resin (A) is preferably 15 moll or less, more preferably 10 mol% or less. When the repeating unit containing an acid group is contained in the resin (A) , the content thereof based on all the repeating units of the resin (A) is usually 1 mol% or above .

Specific examples of the repeating units each containing an acid group are shown below,, whLch_h.o-W-e-V-.e.r. in no way limit the scope of the present invention.

In the specific examples, Rx represents H, CH3, CH ₂ OH or CF3.

The resin (A) according to the present invention can further comprise a repeating unit having an alicyclic hydrocarbon structure in which no polar group

(for example, the above acid group, hydroxyl group or cyano group) is introduced and exhibiting no acid- decomposability . This makes it feasible to reduce any leaching of low-molecular components from the resist film into the immersion liquid in the stage of liquid- immersion exposure and further to appropriately

regulate the solubility of the resin in the stage of development using a developer comprising an organic solvent. As such a repeating unit, there can be mentioned any of the repeating units of general formula

(IV) below.

In general formula (IV), R5 represents a hydrocarbon group -having at least one cyclic structure in which no polar group is introduced.

Ra represents a hydrogen atom, an alkyl group or group of the formula -CH2-0-Ra2- In this formula, Ra2 represents a hydrogen atom, an alkyl group or an acyl group. Ra is preferably a hydrogen atom, a methyl group, a hydroxymethyl group or a trifluoromethyl group, most preferably a hydrogen atom or a methyl group .

The cyclic structures introduced in R5 include a monocyclic hydrocarbon group and a polycyclic

hydrocarbon group. As the monocyclic hydrocarbon group, there can be mentioned, for example, a

cycloalkyl group having 3 to 12 carbon atoms, such as cyclopentyl group, a cyclohexyl group, a cycloheptyl group or a cyclooctyl group, or a cycloalkenyl group having 3 to 12 carbon atoms, such as a cyclohexenyl group. Preferably, the monocyclic hydrocarbon group i a monocyclic hydrocarbon group having 3 to 7 carbon atoms. A cyclopentyl group and a cyclohexyl group can be mentioned as more preferred monocyclic hydrocarbon groups.

The polycyclic hydrocarbon groups include ring- assembly hydrocarbon groups and crosslinked-ring hydrocarbon groups. Examples of the ring-assembly hydrocarbon groups include a bicyclohexyl group and a perhydronaphthalenyl group. As the crosslinked-ring hydrocarbon rings, there can be mentioned, for example, bicyclic hydrocarbon rings, such as pinane, bornane, norpinane, norbornane and bicyclooctane rings (e.g., bicyclo [2.2.2 ] octane ring or bicyclo [ 3.2.1 ] octane ring) ; tricyclic hydrocarbon rings, such as

homobledane, adamantane, tricyclo 6] decane and tricyclo [ 4.3.1. r 5 ] undecane rings; and tetracyclic hydrocarbon rings, such as

tetracyclo [4.4.0. , 10] dodecane and perhydro-1 , 4- methano-5, 8-methanonaphthalene rings. Further, the crosslinked-ring hydrocarbon rings include condensed- ring hydrocarbon rings, for example, condensed rings resulting from condensation of multiple 5- to 8- membered cycloalkane rings, such as perhydronaphthalene (decalin) , perhydroanthracene, perhydrophenanthrene, perhydroacenaphthene, perhydrofluorene, perhydroindene and perhydrophenalene rings.

As preferred crosslinked-ring hydrocarbon rings, there can be mentioned a norb^rjyj _^ group,, an__adamanty-l- group, a bicyclooctanyl group and a

tricyclo [5, 2, 1, O^r 6] decanyl group and the like. As more preferred crosslinked-ring hydrocarbon rings, there can be mentioned a norbornyl group and an

adamantyl group.

Substituents may be introduced in these alicyclic hydrocarbon groups. As preferred substituents, there can be mentioned a halogen atom, an alky1- -group,- a- hydroxyl group having its hydrogen atom substituted, an amino group having its hydrogen atom substituted and the like. The halogen atom is preferably a bromine, chlorine or fluorine atom, and the alkyl group is preferably a methyl, ethyl, butyl or t-butyl group. A substituent may further be introduced in the alkyl group. As the optional further substituent, there can be mentioned a halogen atom, an alkyl group, a hydroxyl group having its hydrogen atom substituted or an amino group having its hydrogen atom substituted.

As the substituent for the hydrogen atom, there can be mentioned, for example, an alkyl group, a cycloalkyl group, an aralkyl group, a substituted methyl group, a substituted ethyl group, an

alkoxycarbonyl group or an aralkyloxycarbonyl group. The alkyl group is preferably an alkyl group having 1 to 4 carbon atoms. The substituted methyl group is preferably a methoxymethyl , methoxythiomethyl,

benzyloxymethyl, t-butoxymethyl or 2- methoxyethoxymethyl group. The substituted ethyl group is preferably a 1-ethoxyethyl or 1-methyl-l- methoxyethyl group. The acyl group is preferably an aliphatic acyl group having 1 to 6 carbon atoms, such as a formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl or pivaloyl group. The alkoxycarbonyl group is, for example, an alkoxycarbonyl group having 1 'to 4 carbon atoms. It is optional for the resin (A) to comprise the repeating unit having an alicyclic hydrocarbon

structure in which no polar group is introduced and exhibiting .no acid-decomposability. When the repeating unit having an alicyclic hydrocarbon structure in which no polar group is introduced and exhibiting no acid- decomposability is contained in the resin (A) , the content thereof based on all the repeating units of the resin (A) is preferably in the range of 1 to 40 mol%, more preferably 1 to 20 mol%.

Particular examples of the repeating units having an alicyclic hydrocarbon structure in which no polar group is introduced and exhibiting no acid- decomposability are shown below, which in no way limit the scope of the present invention. In the formulae, Ra represents H, CH3, CH2OH or CF3.

The resin (A) for use in the composition of the present invention can comprise, in addition to the foregoing repeating structural units, various repeating structural units for the purpose of regulating the dry etching resistance, standard developer adaptability, substrate adhesion, resist profile and generally required properties of the actinic-ray- or radiation- sensitive resin composition such as resolving power, heat resistance and sensitivity.

As such repeating structural units, there can be mentioned those corresponding to the following

monomers, which however are nonlimiting.

The use of such repeating structural units would realize fine regulation of the required properties of the resin for use in the composition of the present invention, especially:

(1) solubility in applied solvents,

(2) film forming easiness (glass transition point) ,

(3) alkali developability,

(4) film thinning (selections of

hydrophilicity/hydrophobicity and alkali-soluble group) ,

(5) adhesion of unexposed area to substrate,

(6) dry etching resistance, etc.

As appropriate monomers, there can be mentioned, for example, a compound having one unsaturated bond capable of addition polymerization, selected from among acrylic esters, methacrylic esters, acrylamides, methacrylamides , allyl compounds, vinyl ethers, vinyl esters and the like.

In addition, any unsaturated compound capable of addition polymerization that is copolymerizable with monomers corresponding to the above various repeating structural units may be copolymerized therewith.

In the resin (A) for use in the composition of the present invention, the molar ratios of individual repeating structural units contained are appropriately determined from the viewpoint of regulating the dry etching resistance, standard developer adaptability, substrate adhesio and resist profile of the actinic- ray- or radiation-sensitive resin composition and generally required properties of the resist such as resolving power, heat resistance and sensitivity.

The resin (A) according to the present invention may have any of the random, block, comb and star forms.

The resin (A) can be synthesized by,_for_e_xamp,l.e., t.h.e_ radical, cation or anion polymerization of unsaturated monomers corresponding to given structures.

Alternatively, the intended resin can be obtained by first polymerizing unsaturated monomers corresponding to the precursors of given structures and thereafter carrying out a polymer reaction.

When the composition of the present invention is one for ArF exposure, from the viewpoint of transparency to ArF light, it is preferred for the resin (A) for use in the composition of the present invention to contain substantially no aromatic ring (in particular, the ratio of repeating unit containing an aromatic group in the resin is preferably 5 mol% or less, more preferably 3 mol% or less, and ideally

0 mol%, namely, containing no aromatic group) .

When the composition of the present invention contains a hydrophobic resin (HR) to be described hereinafter, it is preferred for the resin (A) to contain neither a fluorine atom nor a silicon atom from the viewpoint of the compatibility with the hydrophobic resin (HR) .

In the resin (A) for use in the composition of the present invention, preferably, all the repeating units thereof are comprised of (meth) acrylate repeating units. In that instance, use can be made of any of a resin wherein all the repeating units are comprised of methacrylate repeating units, a resin wherein_a,Ll_the^ repeating units are comprised of acrylate repeating units and a resin wherein all the repeating units are comprised of methacrylate repeating units and acrylate repeating units. However, it is preferred for the acrylate repeating units to account for 50 mol% or less of all the repeating units. It is also preferred to employ a copolymer comprising 20 to 50 mol% of

(meth) acrylate repeating units containing an acid-decomposable group, 20 to 50 mol% of

(meth) acrylate repeating units containing a lactone group, 5 to 30 mol% of (meth) acrylate repeating units containing an alicyclic hydrocarbon structure

substituted with a hydroxyl group or a cyano group and 0 to 20 mol% of other (meth) acrylate repeating units.

In the event of exposing the composition of the present invention to KrF excimer laser beams, electron beams, X-rays or high-energy light rays of wavelength 50 nm or less (EUV, etc.), it is preferred for the resin (A) to further comprise a hydroxystyrene

repeating unit. More preferably, the resin (A)

comprises a hydroxystyrene repeating unit, a

hydroxystyrene repeating unit protected by an acid- decomposable group and an acid-decomposable repeating unit of a (meth) acrylic acid tertiary alkyl ester, etc.

As preferred hydroxystyrene repeating units containing an acid-decomposable group, there can be

butoxycarbonyloxystyrene, a 1-alkoxyethoxystyrene and a (meth) acrylic acid tertiary alkyl ester. Repeating units derived from a 2-alkyl-2-adamantyl (meth) acrylate and a dialkyl ( 1-adamantyl ) methyl (meth) acrylate are more preferred.

The resin (A) according to the present invention can be synthesized in accordance with routine methods (for example, radical polymerization). As general synthesizing methods, there can be mentioned, for example, a batch polymerization method in which a monomer species and an initiator are dissolved in a solvent and heated to thereby carry out polymerization, a dropping polymerization method in which a solution of monomer species and initiator is dropped into a heated solvent over a period of 1 to 10 hours, and the like. The dropping polymerization method is preferred. As a reaction solvent, there can be mentioned, for example, an ether such as tetrahydrofuran, 1,4-dioxane or diisopropyl ether, a ketone such as methyl ethyl ketone or methyl isobutyl ketone, an ester solvent such as ethyl acetate, an amide solvent such as

dimethylformamide or dimethylacetamide, or the solvent capable of dissolving the composition of the present invention, such as propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether or

cyclohexanone, to be described hereinafter.

Preferably, the polymerization is carried out with the use of the same solvent as that used in .the actinic- ray- or radiation-sensitive resin composition of the present invention. This would inhibit any particle generation during storage.

The polymerization reaction is preferably carried out in an atmosphere comprised of an inert gas, such as nitrogen. or argon. The polymerization is initiated by use of a commercially available radical initiator (azo initiator, peroxide, etc.) as a polymerization

initiator. Among the radical initiators, an azo initiator is preferred, and azo initiators having an ester group, a cyano group and a carboxyl group are especially preferred. As specific preferred

initiators, there can be mentioned

azobisisobutyronitrile, azobisdimethylvaleronitrile , dimethyl 2, 2' -azobis (2-methylpropionate) and the like. If desirable, the initiator may be supplemented, or may be added in fractional amounts. After the completion of the reaction, the reaction liquid is poured into a solvent, and the intended polymer is recovered by a method of powder or solid recovery or the like. The reaction concentration is in the range of 5 to

50 mass%, preferably 10 to 30 mass%. The reaction temperature is generally in the range of 10 to 150°C, preferably 30 to 120°C. and more preferably 60 to 100°C.

After the completion of the reaction, the reaction mixture is allowed to stand still to cool _t.o_r.aom— temperature and purified. In the purification, use can be made of routine methods, such as a liquid-liquid extraction method in which residual monomers and oligomer components are removed by water washing or by the use of a combination of appropriate solvents, a method of purification in solution form such as

ultrafiltration capable of extraction removal of only components of a given molecular weight or below, a re-precipitation method in which a resin solution is dropped into a poor solvent to thereby coagulate the resin in the poor solvent and thus remove residual monomers, etc., and a method of purification in solid form such as washing of a resin slurry obtained by filtration with the use of a poor solvent. For example, the reaction solution is brought into contact with a solvent wherein the resin is poorly soluble or insoluble (poor solvent) amounting to 10 or less, preferably 10 to 5 times the volume of the reaction solution to thereby precipitate the resin as a solid.

The solvent for use in the operation of

precipitation or re-precipitation from a polymer solution (precipitation or re-precipitation solvent) is not limited as long as the solvent is a poor solvent for the polymer. Use can be made of any solvent appropriately selected from among a hydrocarbon, a halogenated hydrocarbon, a nitro compound, an ether, a ketone, an ester, a carbonate, an alcohol, a carboxylic acid, water, a mixed solvent containing these solvents and the like, according to the type of the polymer. Of these, it is preferred to employ a solvent containing at least an alcohol (especially methanol or the like) or water as the precipitation or re-precipitation solvent .

The amount of precipitation or re-precipitation solvent used can be appropriately selected taking efficiency, yield, etc. into account. Generally, the amount is in the range of 100 to 10,000 parts by mass, preferably 200 to 2000 parts by mass and more

preferably 300 to 1000 parts by mass per 100 parts by mass of polymer solution.

The temperature at which the precipitation or re- precipitation is carried out can be appropriately selected taking efficiency and operation easiness into account. Generally, the temperature is in the range of about 0 to 50°C, preferably about room temperature (for example, about 20 to 35°C) . The operation of

precipitation or re-precipitation can be carried out by a routine method, such as a batch or continuous method, with the use of a customary mixing container, such as an agitation vessel.

The polymer resulting from the precipitation or re-precipitation is generally subjected to customary solid/liquid separation, such as filtration or

centrifugal separation, and dried before use, Th.e_ filtration is carried out with the use of a filter medium ensuring solvent resistance, preferably under pressure. The drying is performed at about 30 to

100°C, preferably about 30 to 50°C under ordinary pressure or reduced pressure (preferably reduced pressure) .

Alternatively, after the precipitation and

separation of the resin, the resultant resin may be once more dissolved in a solvent and brought into contact with a solvent in which the resin is poorly soluble or insoluble. Specifically, the method may include the operations of, after the completion of the radical polymerization reaction, bringing the polymer into contact with a solvent wherein the polymer is poorly soluble or insoluble to thereby attain resin precipitation (operation a) , separating the resin from the solution (operation b) , re-dissolving the resin in a solvent to thereby obtain a resin solution A

(operation c) , thereafter bringing the resin solution A into contact with a solvent wherein the resin is poorly soluble or insoluble amounting to less than 10 times (preferably 5 times or less) the volume of the resin solution A to thereby precipitate a resin solid

(operation d) and separating the precipitated resin (operation e) .

Further, the operation of dissolving a synthesized resin in a solvent to jth.ereby__optain a solution and heating the solution at about 30 to 90°C for about 30 minutes to 4 hours as described in, for example, JP-A-2009-037108 may be added in order to inhibit any aggregation, etc. of the resin after the preparation of the composition.

The weight average molecular weight of the resin (A) for use in the composition of the present

invention, in terms of. polystyrene-equivalent value ^" measured by GPC, is preferably in the range of 1000 ^' to 200,000. It is more preferably in the range of 2000 to 100,000, further more preferably 3000 to 70,000 and most preferably 5000 to 50,000. By regulating the weight average molecular weight so as to fall within the range of 1000 to 200,000, not only can any

deteriorations of heat resistance and dry etching resistance be prevented but also any deterioration of developability and any increase of viscosity leading to poor film forming property can be prevented.

The polydispersity index (molecular weight

distribution) of the resin is generally in the range of 1.0 to 3.0, preferably 1.0 to 2.6, more preferably 1.1 to 2.5, further more preferably 1.2 to 2.4 and most preferably 1.3 to 2.2. Especially preferred use is made of a resin whose polydispersity index is in the range of 1.4 to 2.0. When the molecular weight

distribution falls within these ranges, excellent resolution and resist shape can be attained, and the side wall of resist pattern is smooth to thereby ensure excellent roughness characteristics.

In the actinic-ray- or radiation-sensitive resin composition of the present invention, the content of resin (A) in the whole composition is preferably in the range of 30 to 99 mass%, more preferably 60 to

95 mass%, based on the total solids of the composition.

One of the above-mentioned resins (A) according to the present invention may be used alone, or two or more thereof may be used in combination. The actinic-ray- or radiation-sensitive resin composition of the present invention may further comprise resins other than the resins (A) .

[2] Compound (B) that when exposed to actinic rays or radiation, generates acid

The composition of the present invention comprises a compound (B) (hereinafter also referred to as "acid generator" or "compound (B) ") expressed by any of general formulae (B-l) to (B-3) below, which compound when exposed to actinic rays or radiation, generates an acid.

First, the compounds (B) of general formula (B-l) below will be described.

In general formula (B-l) above,

A ⁺ represents a sulfonium cation or an iodonium cation,

m is 0 or 1,

n is an integer of 1 to 3, and

¾1 represents an ether bond (-0-), an ester bond (-OCO- or -COO-) or a sulfonic ester bond (-OSO2- or -SO2-O-) . Xfoi is preferably an ester bond (-0C0- or -COO-) or a sulfonic ester bond (-OSO2- or -SO2-O-) . ¾2 represents a substituent having 6 or more carbon atoms.

It is preferred for the substituent having 6 or more carbon atoms represented by R _j -,2 to be a bulky group. As examples thereof, there can be mentioned an alkyl group, an alicyclic group, an aryl group and a heterocyclic group each having 6 or more carbon atoms.

The alkyl group having 6 or more carbon atoms represented by ϊ¾2 may be linear or branched. A linear or branched alkyl group having 6 to 20 carbon atoms is preferred. As examples thereof, there can be mentioned a linear or branched hexyl group, a linear or branched heptyl group and a linear- or branched octyl group.

From the viewpoint of bulkiness, branched alkyl groups are preferred.

The alicyclic group having 6 or more carbon atoms represented by ¾,2 may be monocyclic or polycyclic. The monoalicyclic group is, for example, a

monocyclojj^yl__qroup, such as a cvclohoxvl grouo or a cyclooctyl group. The polyalicyclic group is, for example, a polycycloalkyl group, such as a norbornyl group, a tricyclodecanyl group, a tetracyclodecanyl group, a tetracyclododecanyl group or an adamantyl group. Of the mentioned groups, alicyclic groups each with a bulky structure having 7 or more carbon atoms, such as a norbornyl group, a tricyclodecanyl group, a tetracyclodecanyl group, a tetracyclododecanyl group and an adamantyl group, are preferred from the

viewpoint of inhibiting any in-film diffusion in the operation of post-exposure bake (PEB) and enhancing MEEF (mask error enhancement factor) .

The aryl group having 6 or more carbon atoms represented by ϊ¾2 may be monocyclic or polycyclic. As the aryl group, there can be mentioned, for example, a phenyl group, a naphthyl group, a phenanthryl group or an anthryl group. Of these, a naphthyl group

exhibiting a relatively low light absorbance at 193 nm is preferred.

The heterocyclic group having 6 or more carbon atoms represented by ¾2 may be monocyclic or

polycyclic. The polycyclic structure is superior in the inhibition of any acid diffusion. It is optional for the heterocyclic group to have aromaticity. As the heterocycle having aromaticity, there can be mentioned, for example, a benzofuran ring, a benzothiophene ring, a dibenzofuran ring or a dibenzothiophene ring. As the heterocycle having no aromaticity, there can be

mentioned, for example, a tetrahydropyran ring, a lactone ring or a decahydroisoquinoline ring. It is especially preferred for the heterocycle in the

heterocyclic group to be a benzofuran ring or a

decahydroisoquinoline ring. As examples of the lactone rings, there can be mentioned the lactone structures set forth above by way of example in connection with the resin (A) .

A further substituent may be introduced in the substituent having 6 or more carbon atoms represented by R52 · ^As the further substituent, there can be mentioned, for example, an alkyl group (may be linear or branched, preferably having 1 to 12 carbon atoms) , a cycloalkyl group (may be any of a monocycle, a

polycycle and a spiro ring, preferably having 3 to 20 carbon atoms) , an aryl group (preferably having 6 to 14 carbon atoms) , a hydroxyl group, an alkoxy group, an ester group, an amido group, a urethane group, a ureido group, a thioether group, a sulfonamido group or a sulfonic ester group. The carbon (carbon contributing to ring formation) as a constituent of the above alicyclic group, aryl group and heterocyclic group may be a carbonyl carbon.

Particular examples of the anion structures of the compounds (B) of general formula (B-l) are shown below,

invention .

o o

general formula (B-2) above,

A ⁺ represents a sulfonium cation or an iodonium cation, and

Qbl represents a group containing a lactone structure, a group containing a sultone structure or a group containing a cyclocarbonate structure.

As the lactone structure and sultone structure in Qbl' there can be mentioned, for example, those in the repeating units with a lactone structure or sultone structure set forth above in connection with the resin (A) . In particular, there can be mentioned the lactone structures of any of general formulae (LCl-1) to (LC1- 17) above and the sultone structures of any of general formulae (SLl-1) to (SL1-3) above.

The lactone structure or sultone structure may be directly bonded to the oxygen atom of the ester group in general formula (B-2) above. Alternatively, the lactone structure or sultone structure may be bonded to the oxygen atom of the ester group via an alkylene group (for example, a methylene group or an ethylene group) . In that instance, the group containing a lactone structure or sultone structure can be stated as being an alkyl group containing the lactone structure or sultone structure as a substituent.

The cyclocarbonate structure in Q^^ is preferably a 5- to 7-membered cyclocarbonate structure. As such, the e can be mentioned a 1 , 3-dioxoran-2-one , a 1,3- dioxan-2-one or the like.

The cyclocarbonate structure may be directly bonded to the oxygen atom of the ester group in' general formula (B-2) above. Alternatively, the cyclocarbonate structure may be bonded to the oxygen atom of the ester group via an alkylene group (for example, a methylene group or an ethylene group) . In that instance, the group containing a cyclocarbonate structure can be stated as being an alkyl group containing the

cyclocarbonate structure as a substituent.

Particular examples of the anion structures in the compounds (B) of general formula (B-2) are shown below, which in no way limit the scope of the present

invention.

Now, the compounds (B) of general formula

below will be described.

In general formula (B-3) above,

A ⁺ represents a sulfonium cation or an iodonium cation.

LJ ₃ 2 represents an alkylene group, for example, a methylene group, an ethylene group, a propylene group or a butylene group. An ^" alkylene group having 1 to 6 carbon atoms is preferred, and an alkylene group having 1 to 4 carbon atoms is more preferred.

¾>2 represents an e,ther bond (-0-) or an ester bond (-0C0- or -C00-) .

_Q| 7_ represents a cycloal kyl_g.r_o,up—οχ_a—gxo-up- containing an aromatic ring.

The cycloalkyl group represented by Q^2 ^ma Y be monocyclic or polycyclic. As the monocycloalkyl group, there can be mentioned, for example, a cyclopentyl group, a cyclohexyl group or a cyclooctyl group. As the polycycloalkyl group, there can be mentioned, for example, a norbornyl group, a tricyclodecanyl group, a tetracyclodecanyl group, a tetracyclododecanyl group or an adamantyl group. Of these, cycloalkyl groups with a bulky structure having 7 or more carbon atoms, such as a norbornyl group, a tricyclodecanyl group, a

tetracyclodecanyl group, a tetracyclododecanyl group and an adamantyl group, are preferred.

The aromatic ring in the group containing an aromatic ring represented by Qj-,2 is preferably an aromatic ring having 6 to 20 carbon atoms. As such, there can be mentioned a benzene ring, a naphthalene ring, a phenanthrene ring, an anthracene ring or the ^' like. A benzene ring or a naphthalene ring is more preferred. This aromatic ring may be substituted with at least one fluorine atom. The aromatic ring

substituted with at least one fluorine atom is, for example, a perfluorophenyl group.

The aromatic ring may be directly bonded to X¾2 · Alternatively, the aromatic ring may be bonded to Xj^ via an alkylene group (for example, a ^' methylene group or an ethylene__group) . In that instance,, the group containing an aromatic ring can be stated as being an alkyl group containing the aromatic ring as a

substituent .

Particular examples of the anion structures in the compounds (B) of general formula (B-3) are shown below, which in no way limit the scope of the present

invention.

In general formulae (B-l) to (B- 3 ) above,

it is preferred for the sulfonium cation

represented by A ⁺ to have any of cation structures of general formula (ZI) below, and it is preferred for the iodonium cation represented by A ⁺ to have any of cation structures of general formula (ZII) below.

In general formulae (ZI) and (ZII) above,

each of R20I' ^202 ^anc * ^203 independently

represents an organic group.

The number of carbon atoms of each of the organic groups represented by R20I' ¾02 ^anc ^ ^203 ^ ^s generally in the range of 1 to 30, preferably 1 to 20.

Any two of R20I to R203 ^ma Y ¹ ° ^e bonded to each other to thereby form a ring structure, and the. ring within the same may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond or a carbonyl group. As the group formed by the bonding of two of R20I to ^203' there can be mentioned an alkylene group (for example, a butylene group or a pentylene group) .

Each of 204 ^anc * ¾05 independently represents an aryl group, an alkyl group or a cycloalkyl group.

Each of the aryl groups ^' represented by ¾204 ^an d R.205 is preferably a phenyl group or a naphthyl group, more preferably a phenyl group. Each of the aryl groups represented by R204 ^anc * ^205 ^ma ^ ^{e one nav} i ^n< 3 ^a heterocyclic structure containing an oxygen atom, a nitrogen atom, a sulfur atom or the like. As the skeleton of each of the aryl groups having a

heterocyclic structure, there can be mentioned, for example, pyrrole, furan, thiophene, indole, benzofuran, benzothiophene or the like.

As preferred alkyl groups and cycloalkyl groups represented by R20 ^an< ^ ¾05' there can be mentioned a linear or branched alkyl group having 1 to 10 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, a butyl group or a pentyl group) and a cycloalkyl group having 3 to 10 carbon atoms (a

cyclopentyl group, a cyclohexyl group or a norbornyl group) .

Substituents may be introduced in the aryl groups, alkyl groups and cycloalkyl groups represented by R204 and 205- ^s the substituents optionally introduced in the aryl groups, alkyl groups and cycloalkyl groups represented by 204 ^anc ^ ^R 205' there can be mentioned, for example, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (for example, 6 to 15 carbon atoms) , an alkoxy group (for example, 1 to 15 carbon atoms) , a halogen atom, · a hydroxyl group, a phenylthio group and the like.

As the organic groups represented by 20I' ^202 and R203' there can be mentioned, for example,

corresponding groups in the cation structures (ZI-1), (ZI-2), (ZI-3) and (ZI-4) to be described hereinafter.

As preferred cation -structures among those of general formula (ZI) above, there can be mentioned cation structures (ZI-1), (ZI-2), (ZI-3) and (ZI-4) to be described hereinafter.

The cation structure (ZI-1) is any of the cation structures of general ^■ formula (ZI) above in which at least one of R20I to R203 ^ ^{s an ar} yl group, namely, an arylsulfonium cation structure.

In this arylsulfonium cation structure, all of R201 to R203 ^ma Y b ^e ¾ ^r yl groups. Alternatively, R2OI to R203 ^ma k ^{e an ar} yl group. in part and may be an alkyl- group or a cycloalkyl group in the remainder.

As the arylsulfonium cation structure, there can be mentioned, _for_jsxample __a_^rj ₌ ar.y_lsu.l.f.oni.um_cation structure, a diarylalkylsulfonium cation structure, an aryldialkylsulfonium cation structure, a

diarylcycloalkylsulfonium cation structure or an aryldicycloalkylsulfonium cation structure.

The aryl group in the arylsulfonium cation structure is preferably a phenyl group or a naphthyl group, more preferably a phenyl group. The aryl group may be one with a heterocyclic structure containing an oxygen atom, a nitrogen atom, a sulfur atom or the like. As the heterocyclic structure, there can be mentioned a pyrrole residue, a furan residue, a

thiophene residue, an indole residue, a benzofuran residue, a benzothiophene residue or the like. When the arylsulfonium cation structure contains two or more aryl groups, the two or more aryl groups may be

identical to or different from each other.

The alkyl group or cycloalkyl group contained in the arylsulfonium cation structure according to

necessity is preferably a linear or branched alkyl group having 1 to 15 carbon atoms or a cycloalkyl group having 3 to 15 carbon atoms. As such, there can be mentioned, for example, a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a t-butyl group,, a cyclopropyl group, a cyclobutyl group, a cyclohexyl group, an adamantyl group or the like.

Each of the aryl groups, alkyl groups and

cycloalkyl groups represented by 201 ^o R203 ^ma Y contain as a substituent thereof an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (for example, 6 to 14 carbon atoms), an alkoxy group (for example, 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, a phenylthio group or an arylsulfonyl group. Preferred substituents are a linear or branched alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms and a linear, branched or cyclic alkoxy group having 1 to 12 carbon atoms. An alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 4 carbon atoms are more preferred. Each of the substituents may be introduced in any one of the three 201 to R203' ^or alternatively may be introduced in all of the three 20I to R203- When 201 to R203 represent aryl groups, each of the substituents is preferably introduced in the p-position of the aryl group.

Now, the cation structure (ZI-2) will be

described .

The cation structure (ZI-2) is any of those of general formula (ZI) wherein each of R20I to R203 independently represents an organic group containing no aromatic ring. The aromatic rings include an aromatic ring containing a heteroatom.

Each of the organic groups containing no aromatic ring represented by R201 to R203 generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.

Preferably, each of R20I to R203 independently represents an alkyl group, a cycloalkyl group, an allyl group or a vinyl group. A linear or branched 2- oxoalkyl group, a 2-oxocycloalkyl group and an

alkoxycarbonylmethyl group are more preferred. A linear or branched 2-oxoalkyl group i-s most preferred.

As preferred alkyl groups and cycloalkyl groups represented by 20I ^{to R} 203' there can be mentioned a linear or branched alkyl group having 1 to 10 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, a butyl group or a pentyl group) and a cycloalkyl group having 3 to 10 carbon atoms (a cyclopentyl group, a cyclohexyl group or a norbornyl group) . The alkyl group is more preferably a 2- oxoalkyl group or an alkoxycarbonylmethyl group. The cycloalkyl group is more preferably a 2-oxocycloalkyl group .

The 2-oxoalkyl group may be linear or branched, preferably being a group resulting from the

introduction of >C=0 in the 2-position of any of the above alkyl groups.

The 2-oxocycloalkyl group is preferably a group resulting from the introduction of >C=0 in the 2- position of any of the above cycloalkyl groups.

As preferred alkoxy groups in the

jaJoxycjy:bo^ there can. be mentioned alkoxy groups each having 1 to 5 carbon atoms (a methoxy group, an ethoxy group, a propoxy group, a butoxy group and a pentoxy group) .

These R20I ^{to R} 203 ^ma Y be further substituted with a halogen atom, an alkoxy group (for example, 1 to 5 carbon atoms) , a hydroxyl group, a cyano group or a nitro group.

The cation structure (ZI-3) has any of the structures of general formula (ZI-3) below, being a phenacylsulfonium salt structure.

In general formula (ZI-3) ,

each of R_ _c to R5 _C independently represents a. hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a halogen atom or a phenylthio group.

Each of Rg _c and R7 _C independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, a cyano group or an aryl group.

Each of R _x and Ry independently .represents an alkyl group, a cycloalkyl group, a 2-oxoalkyl group, a 2-oxocycloalkyl group, an alkoxycarbonylalkyl group, an allyl group or a vinyl group. ■

Any two or more of R]_ _c to R5 _C , and Rg _c and R7 _C , and R _x and Ry may be bonded to each other to thereby form a ring structure. This ring structure may contain an oxygen atom, a sulfur atom, an ester bond or an amide bond. As the group formed by the mutual bonding of any two or more of R]_ _c to 5 _C , and Rg _c and R7 _C , and R _x and Ry, there can be mentioned a butylene group, a pentylene group or the like.

Each of the alkyl groups represented by R _] _ _c to R7 _C may be linear or branched. As such, there can be mentioned, for example, an alkyl group having 1 to 20 carbon atoms, preferably a linear or branched alkyl group having 1 to 12 carbon atoms (for example, a methyl group, an ethyl group, a linear or branched propyl group, a linear or branched butyl group or a linear or branched pentyl group) . As the cycloalkyl group, there can be mentioned, for example, a

cycloalkyl group having 3 to 8 carbon atoms (for example, a cyclopentyl group or a cyclohexyl group) .

Each of the alkoxy groups represented by R]_ _c to R5 _C may be linear, or branched, or cyclic. As such, there can be mentioned, for example, an alkoxy group having 1 to 10 carbon atoms, preferably a linear or branched alkoxy group having 1 to 5 carbon atoms (for example, a methoxy group, an ethoxy group, a linear or branched propoxy group, a linear or branched butoxy group or a linear or branched pentoxy group) , and a cycloalkoxy group having 3 to 8 carbon atoms (for example, a cyc1openty1oxy_qr uB—oJ__a_c_y-C.Lohexylox-y- group) .

Preferably, any one of R _] _ _c to R5 _C is a linear or branched alkyl group, a cycloalkyl group or a linear, branched or cyclic alkoxy group. More preferably, the sum of carbon atoms of R]_ _c ^to ^-5c i ^s ^ ⁿ the range of 2 to 15. Accordingly, there can be attained an

enhancement of solvent solubility and inhibition of particle occurrence during storage. Each of the aryl groups represented by Rg _c and R7 _C preferably has 5 to 15 carbon atoms. As such, there can be mentioned, for example, a phenyl group or a naphthyl group.

When Rg _c and R7 _C are bonded to each other to thereby form a ring, the group formed by the mutual bonding of Rg _c and R7 _C is preferably an alkylene group having 2 to 10 carbon atoms. As such, there can be mentioned, for example, an ethylene group, a propylene group, a butylene group, a pentylene group, __a hexylene group or the like. Further, the ring formed by the mutual bonding of Rg _c and R7 _C may contain a heteroatom, such as an oxygen atom, within the ring.

As the alkyl groups and cycloalkyl groups

represented by R _x and Ry, there can be mentioned the same alkyl groups and cycloalkyl groups as set forth above with respect to R]_ _c to 7 _C .

As the 2-oxoalkyl group and 2-oxocycloalkyl group, there can be mentioned the alkyl group and cycloalkyl group represented by R]_ _c to R7 _C having >C=0 introduced in the 2-position thereof.

With respect to the alkoxy group in the

alkoxycarbonylalkyl group, there can be mentioned the same alkoxy groups as mentioned above with respect to R]_ _c to R5 _C . As the alkyl group thereof, there can be mentioned, for example, an alkyl group having 1 to 12 carbon atoms, preferably a linear alkyl group having 1 to 5 carbon atoms (e.g., a methyl group or an ethyl group) .

The allyl groups are not particularly limited. However, preferred use is made of an unsubstituted allyl group or an allyl group substituted with a mono- or polycycloalkyl group.

The vinyl groups are not particularly limited. However, preferred use is made of an unsubstituted vinyl group or a vinyl group substituted with a mono- or polycycloalkyl group.

As the ring structure that may be formed by the mutual bonding of R _x and Ry, there can be mentioned a 5-membered or 6-membered ring, especially preferably a 5-membered ring (namely, a tetrahydrothiophene ring) , formed by bivalent R _x and Ry (for example, a methylene group, an ethylene group, a propylene group or the like) in cooperation with the sulfur atom in general formula (ZI-3) above. An oxygen atom is preferably introduced in the ring formed by the mutual bonding of R _x and Ry.

Each of R _x and R _y is preferably an alkyl group or cycloalkyl group having 4 or more carbon atoms, more preferably 6 or more carbon atoms and further more preferably 8 or more carbon atoms.

Particular examples of the cation structures (ZI- 3) are shown below. 

The . cation structures (ZI will be described below.

The cation structures (ZI are expressed by general formula (ZI- 4 ) below.

In general formula (ZI-4),

R_3 represents a hydrogen atom, a fluorine atom, a hydroxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group or a group containing a cycloalkyl group. Substituents may be introduced in these groups.

Rl4, or each of R]_4S independently, represents a hydroxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, an alkylsulfonyl group, a cycloalkylsulfonyl group or a group containing a cycloalkyl group.

Substituents may be introduced in these groups.

Each of R15S independently represents an alkyl group, a cycloalkyl group or a naphthyl group, provided that two R15S may be bonded to each other to thereby form a ring in cooperation with the sulfur atom to which R _] _5 is bonded. This ring structure may contain an oxygen atom, an ion atom, a ketone group, an ester bond and/or an amide bond. Substituents may be

introduced in these groups.

In the formula, t is an integer of 0 to 2, and r is an integer of 0 to 8.

Each of the alkyl groups represented by R13, R14 and R _] _5 in general formula (ZI-4) is linear or

branched, preferably having 1 to 10 carbon atoms. A methyl group, an ethyl group, an n-butyl group, a t- butyl group and the like are preferred.

As the cycloalkyl groups represented by R13, 4 and R_5, there can be mentioned mono- and

polycycloalkyl groups (preferably a cycloalkyl group having 3 to 20 carbon atoms). In particular,

cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl are preferred.

Each of the alkoxy groups represented by R^3 and R^4 is linear or branched, preferably having 1 to 10 carbon atoms. A methoxy group, an ethoxy group, an n- propoxy group, an n-butoxy group and the like are preferred.

Each of the alkoxycarbonyl groups represented by R _] _3 and R]_4 is linear or branched, preferably having 2 to 11 carbon atoms. A methoxycarbonyl group, an ethoxycarbonyl group, an n-butoxycarbonyl group and the like are preferred.

As the groups containing a cycloalkyl group represented by R^3 and R14, there can be mentioned mono- and polycycloalkyl groups (preferably a

cycloalkyl group having 3 to 20 carbon atoms). For example, there can be mentioned a mono- and

polycycloalkyloxy group and an alkoxy group containing a mono- and polycycloalkyl group. Substituents may further be introduced in these groups.

Each of the mono- and polycycloalkyloxy groups represented by R^3 and R14 preferably has 7 or more carbon atoms in total, more preferably 7 to 15 carbon atoms in total. Preferably, a monocycloalkyl group is contained therein. The monocycloalkyloxy group having 7 or more carbon atoms in total refers to, a ·

monocycloalkyloxy group comprised of a cycloalkyloxy group, such as a cyclopropyloxy group, a cyclobutyloxy group, a cyclopentyloxy group, a cyclohexyloxy group, a cycloheptyloxy group, a cyclooctyloxy group or a cyclododecanyloxy group, optionally substituted with an alkyl group such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, dodecyl, 2-ethylhexyl , isopropyl, sec-butyl, t-butyl or isoamyl, a hydroxyl group, a halogen atom (fluorine, chlorine, bromine or iodine) , a nitro group, a cyano group, an amido group, a sulfonamide group, an alkoxy group such as methoxy, ethoxy, hydroxyethoxy, propoxy, hydroxypropoxy or butoxy, an alkoxycarbonyl group such as methoxycarbonyl or ethoxycarbonyl , an acyl group such as formyl, acetyl or benzoyl, an acyloxy group such as acetoxy or

butyryloxy, a carboxyl group or the like, wherein the sum of carbon atoms thereof including those of any optional substituent introduced in the cycloalkyl group is 7 or greater.

As the polycycloalkyloxy group having 7 or more carbon atoms in total, there can be mentioned a

norbornyloxy group, a tricyclodecanyloxy group, a tetracyclodecanyloxy group, an adamantyloxy group or the like.

Each of the alkoxy groups containing a mono- and polycycloalkyl group represented by R _] _3 and R]_4

preferably has 7 or more carbon atoms in total, more preferably 7 to 15 carbon atoms in total. The alkoxy group containing a monocycloalkyl group is preferred. The alkoxy group containing a monocycloalkyl group, which has 7 or more carbon atoms in total, refers to an alkoxy group, such as methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptoxy, octyloxy, dodecyloxy, 2- ethylhexyloxy, isopropoxy, sec-butoxy, t-butoxy or isoamyloxy, substituted with any of the above-mentioned optionally substituted monocycloalkyl groups, wherein the sum of carbon atoms thereof including those of substituents is, 7 or greater. For example, there can be mentioned a cyclohexylmethoxy group, a

cyclopentylethoxy group, a cyclohexylethoxy group or the like. A cyclohexylmethoxy group is preferred.

As the alkoxy group containing a polycycloalkyl group, which has 7 or more carbon atoms in total, there can be mentioned a norbornylmethoxy group, a

norbornylethoxy group, a tricyclodecanylmethoxy group, a tricyclodecanylethoxy group, a

tetracyclodecanylmethoxy group, a

tetracyclodecanylethoxy group, an adamantylmethoxy group, an adamantylethoxy group or the like. Of these, a norbornylmethoxy group, a norbornylethoxy group and the like are preferred.

With respect to the alkyl group in the

alkylcarbonyl group represented by R14, there can be mentioned the same particular examples as mentioned above with respect to the alkyl groups represented by

^R 13 ^{to R} 15-

Each of the alkylsulfonyl group and

cycloalkylsulfonyl group represented by R _] _4 may be linear, branched or cyclic and preferably has 1 to 10 carbon atoms. As preferred examples thereof, there can be mentioned a methanesulfonyl group, an ethanesulfonyl group, an n-propanesulfonyl group, an n-butanesulfonyl group, a cyclopentanesulfonyl group, a

cyclohexanesulfonyl group and the like. As substituents that may be introduced in these groups, there can be mentioned a halogen atom (e.g., a fluorine atom) , a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an alkoxy group, an alkoxyalkyl group, an alkoxycarbonyl group, an

alkoxycarbonyloxy group and the like.

As the alkoxy group, there can be mentioned, for example, a linear, branched or cyclic alkoxy group having 1 to 20 carbon atoms, such as a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, a 2-methylpropoxy group, a 1- methylpropoxy group, a t-butoxy group, a cyclopentyloxy group or a cyclohexyloxy group.

As the alkoxyalkyl group,, there can be mentioned, for example, a linear, branched or cyclic alkoxyalkyl group having 2 to 21 carbon atoms, such as a

methoxymethyl group, an ethoxymethyl group, . a 1- methoxyethyl group, a 2-methoxyethyl group, a 1-

As the alkoxycarbonyl group, there can be

mentioned, for example, a linear, branched or cyclic alkoxycarbonyl group having 2 to 21 carbon atoms, such as a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, an i-propoxycarbonyl group, an n-butoxycarbonyl group, a 2-methylpropoxycarbonyl group, a 1-methylpropoxycarbonyl group, a t- butoxycarbonyl group, a cyclopentyloxycarbonyl group or 1\ a cyclohexyloxycarbonyl group.

As the alkoxycarbonyloxy group, there can be mentioned, for example, a linear, branched or cyclic alkoxycarbonyloxy group having 2 to 21 carbon atoms, . such as a methoxycarbonyloxy group, an

ethoxycarbonyloxy group, an n-propoxycarbonyloxy group, an i-propoxycarbonyloxy group, an n-butoxycarbonyloxy group, a t-butoxycarbonyloxy group, a ·

cyclopentyloxycarbonyloxy group or a

cyclohexyloxycarbony1oxy group.

As the ring structure that may be formed by the mutual bonding of two R15S, there can be mentioned a 5- or 6-membered ring, most preferably a 5-membered ring (namely, a tetrahydrothiophene ring) , formed by two R15S in cooperation with the sulfur atom in general formula (ZI-4). The ring structure may be condensed with an aryl group or a cycloalkyl group. Substituents may be introduced in bivalent R15S. As such

substituents, there can be mentioned, for example, a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxyalkyl group, an alkoxycarbonyl group, an alkoxycarbonyloxy group and the like. A plurality of substituents may be introduced in the ring structure. The substituents may be bonded to each other to thereby form a ring (e.g., an aromatic or nonaromatic hydrocarbon ring, an aromatic or nonaromatic heterocycle or a polycyclic condensed ring resulting from the combination of two or more mentioned rings). An oxygen atom is preferably contained in the ring formed by the mutual bonding of R15S.

R]_5 in general formula (ZI-4) is preferably a methyl group, an ethyl group, a naphthyl group, a bivalent group occurring at the formation of a

tetrahydrothiophene ring structure upon the mutual bonding of two R15S in cooperation with the sulfur atom, or the like.

Preferred substituents that can be introduced in R]_3 and R]_4 are a hydroxyl group, an alkoxy group, an alkoxycarbonyl group and a halogen atom (especially, a fluorine atom) .

In the formula, t is preferably 0 or 1, more preferably 1; and

r is preferably from 0 to 2.

Particular examples of the cations of the

compounds of general formula IZZ=A.) according to the present invention are shown below.

The composition of the present invention may contain only one, or two or more, of the acid

generators of general formulae (B-l) to (B-3). When two or more of the acid generators of general formulae

(B-l) to (B-3) are contained, it is preferred to use an acid generator containing any of cations of general formula (ZI-1) in combination with an acid generator containing any of cations of general formula (ZI-3) or (ZI-4). In that instance, more preferably, the contained anions are the same.

The composition of the present invention may further contain. any of the following compounds as an acid generator.

84

(288) ( ^z89 )

The content of acid generator (s) based on the total solids of the composition is preferably in the range of 0.1 to 30 mass%, more preferably 0.5 to 25 raassl, further more preferably 3 to 20 mass% and most preferably 3 to 15 massl.

[3] Solvent (C)

The actinic-ray- or radiation-sensitive resin composition of the present invention may contain a solvent. The solvent is not particularly limited as long as it can be used in the preparation of the actinic-ray- or radiation-sensitive resin composition of the present invention. As the solvent, there can be mentioned, for example, an organic solvent, such as an alkylene glycol monoalkyl ether carboxylate, an

alkylene glycol monoalkyl ether, an alkyl lactate, an alkyl alkoxypropionate, a cyclolactone (preferably having 4 to 10 carbon atoms), an optionally cyclized monoketone compound (preferably having 4 to 10 carbon atoms) , an alkylene carbonate, an alkyl alkoxyacetate or an alkyl pyruvate.

As particular examples of these solvents, there can-be mentioned those set forth in Sections [0441] to

[0455] of US Patent Application Publication

No. 2008/0187860.

In the present invention, a mixed solvent

comprised of a mixture of a solvent containing a hydroxyl group in its structure and a solvent

containing no hydroxyl group may be used as the organic solvent.

Compounds set forth above by way of example can be appropriately selected as the solvent containing a hydroxyl group and solvent containing no hydroxyl group. The solvent containing a hydroxyl group is preferably an alkylene glycol monoalkyl ether, an alkyl lactate or the like, more preferably propylene glycol monomethyl ether (PGME, also known as l-methoxy-2- propanol) or ethyl lactate. The solvent containing no hydroxyl group is preferably an alkylene glycol monoalkyl ether acetate, an alkyl alkoxypropionate, an optionally cyclized monoketone compound, a

cyclolactone, an alkyl acetate or the like. Of these, propylene glycol monomethyl ether acetate (PGMEA, also known as l-methoxy-2-acetoxypropane) , ethyl

ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone and butyl acetate are especially

preferred. Propylene glycol monomethyl ether acetate, ethyl ethoxypropionate and 2-heptanone are most preferred .

The mixing ratio (mass) of a solvent having a hydroxyl group and a solvent having no hydroxyl group is in the range of 1/99 to 99/1, preferably 10/90 to 90/10 and more preferably 20/80 to 60/40. A mixed solvent containing 50 mass% or more of solvent

containing no hydroxyl group is especially preferred from the viewpoint of uniform coatability.

The solvent preferably contains propylene glycol monomethyl ether acetate, being preferably a solvent comprised only of propylene glycol monomethyl ether acetate, or a mixed solvent comprised of two or more types of solvents in which propylene glycol monomethyl ether acetate is contained. [4] Hydrophobic resin (HR)

The actinic-ray- or radiation-sensitive resin composition of the present invention may further comprise a hydrophobic resin (hereinafter also referred to as "hydrophobic resin (HR) " or " resin (HR) ") different from the above-described resins (A)

especially when a liquid immersion exposure is applied thereto.

This localizes the hydrophobic resin (HR) in the surface layer of the film. Accordingly, when the immersion medium is water, the static/dynamic contact angle of the surface of the resist film with respect to water can be increased, thereby enhancing the immersion liquid tracking property.

Although the hydrophobic resin (HR) is preferably designed so as to be localized in the interface as mentioned above, as different from surfactants, the hydrophobic resin does not necessarily have to contain a hydrophilic group in its molecule and does not need to contribute toward uniform mixing of polar/nonpolar substances .

From the viewpoint of localization in the surface layer of the film, it is preferred for the hydrophobic resin (HR) to contain at least one member selected from among a "fluorine atom, " a "silicon atom" and a "CH3 partial structure introduced in a side chain portion of the resin." Two or more members may be contained. When the hydrophobic resin (HR) contains a

fluorine atom and/or a silicon atom, in the hydrophobic resin (HR) , the fluorine atom and/or silicon atom may be introduced in the principal chain of the resin, or a side chain thereof.

When the hydrophobic resin (HR) contains a

fluorine atom, it is preferred for the resin to

comprise, as a partial structure containing a fluorine atom, an alkyl group containing a fluorine atom, a cycloalkyl group containing a fluorine atom or an aryl group containing a fluorine atom.

The alkyl group containing a fluorine atom is a linear or branched alkyl group having at least one hydrogen atom thereof substituted with a fluorine atom. This alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 4 carbon atoms. A substituent other than the fluorine atom may further be introduced in the alkyl group containing a fluorine atom.

The cycloalkyl group containing a fluorine atom is a mono- or polycycloalkyl group having at least one hydrogen atom thereof substituted with a fluorine atom. A substituent other than the fluorine atom may further be introduced in the cycloalkyl group containing a fluorine atom.

The aryl group containing a fluorine atom is an aryl group having at least one hydrogen atom thereof substituted with a . fluorine atom. As the aryl group, there can be mentioned, for example, a phenyl or naphthyl group. A substituent other than the fluorine atom may further be introduced in the aryl group containing a fluorine atom.

As preferred examples of the alkyl groups each containing a fluorine atom, cycloalkyl groups each containing a fluorine atom and aryl groups each containing a fluorine atom, there can be mentioned the groups of general formulae (F2) to (F4) below, which however in no way limit the scope of the present invention.

In general formulae (F2) to (F4),

each of R57 to Rgg independently represents a hydrogen atom, a fluorine atom or an alkyl group

-(- -H-e-a-r—e-^-b-r-a-Fte-h-ed-)-— -rovi-ded—that—at—least ^" on—of— each of 57-R6I, at least one of each of Rg2~R64 and at least one of each of R65-R68 represent a fluorine atom or an alkyl group (preferably having 1 to 4 carbon atoms) having at least one hydrogen atom thereof substituted with a fluorine atom.

It is preferred that all of R57-R61 and R65-R67 represent fluorine atoms. Each of R¾2' R63 ^anc ^ ^68 preferably represents a fluoroalkyl group (especially having 1 to 4 carbon atoms) , more preferably a

perfluoroalkyl group having 1 to 4 carbon atoms. When each of Rg2 and R53 represents a perfluoroalkyl group, Rg4 preferably represents a hydrogen atom. R52 ^an d ^63 may be bonded with each other to thereby form a ring.

Specific examples of the groups of general formula (F2) include a p-fluorophenyl group, a

pentafluorophenyl group, a

3, 5-di (trifluoromethyl) phenyl group and the like.

Specific examples of the groups of general formula (F3) include a trifluoromethyl group,

a pentafluoropropyl group, a pentafluoroethyl group, a heptafluorobutyl group, a hexafluoroisopropyl group, a heptafluoroisopropyl group,

a hexafluoro ( 2-methyl ) isopropyl group,

a nonafluorobutyl group, an octafluoroisobutyl group, a nonafluorohexyl group, a nonafluoro-t-butyl group, a perfluoroisopentyl group, a perfluorooctyl group, a__perfJLuoro ( trimethyl Lh_ _yl qxonp-,~

a 2 , 2 , 3 , 3-tetrafluorocyclobutyl group,

a perfluorocyclohexyl group and the like. Of these, a hexafluoroisopropyl group, a heptafluoroisopropyl group, a hexafluoro (2-methyl) isopropyl group,

an octafluoroisobutyl group, a nonafluoro-t-butyl group and a perfluoroisopentyl group are preferred. A hexafluoroisopropyl group and a heptafluoroisopropyl group are more preferred. Specific examples of the groups of general formula (F4) include -C(CF3) ₂ OH, -C(C2F5)20H, -C(CF ₃ ) (CF )OH, -CH(CF ₃ )OH and the like. -C(CF ₃ ) ₂ OH is preferred .

The partial structure containing a fluorine atom may be directly bonded to the principal chain, or may be bonded to the principal chain through a group selected from the group consisting of an alkylene group, a phenylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amido group, a urethane group, and a ureylene group, or through a group composed of a combination of two or more of these groups.

Particular examples of the repeating units each containing a fluorine atom are shown below, which in no way limit the scope of the present invention.

In the particular examples, represents a hydrogen atom, -CH ₃ , -F or -CF ₃ , and X ₂ represents -F or -CF ₃ .

The hydrophobic resin (HR) may contain a silicon atom. It is preferred for the hydrophobic resin (D) to have an alkylsilyl structure (preferably a

trialkylsilyl group) or a cyclosiloxane structure as a partial structure having a silicon atom.

As the alkylsilyl structure or cyclosiloxane structure, there can be mentioned, for example, any of the groups of the following general formulae (CS-1) to (CS-3) or the like.

(CS-1) (CS-2) (CS-3)

In general formulae (CS-1) to (CS-3),

each of R^2 to R26 independently represents a linear or branched alkyl group (preferably having 1 to 20 carbon atoms) or a cycloalkyl group (preferably having 3 to 20 carbon atoms) .

Each of L3 to L5 represents a single bond or a bivalent connecting group. As the bivalent connecting group, there can be mentioned any one or a combination of two or more groups selected from the group

consisting of an alkylene group, a phenylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amido group, a urethane group and a urea group. The sum of carbon atoms of the bivalent connecting group is preferably 12 or less.

In the formulae, n is an integer of 1 to 5. n is preferably an integer of 2 to .

Particular examples of the repeating units having any of the groups of general formulae (CS-1) to (CS-3) are shown below, which in no way limit the scope of the present invention.

In the particular examples, X]_ represents a hydrogen atom, -CH3, -F or -CF3.

As mentioned above, it is preferred for the hydrophobic resin (HR) to contain a CH3 partial structure in its side chain portion.

Herein, the CH3 partial structure (hereinafter also simply referred to as "side-chain CH3 partial structure") contained in a side chain portion of the hydrophobic resin (HR) includes a CH3 partial structure contained in an ethyl group, a propyl group or the like. In contrast, a methyl group (for example, an - methyl group in the repeating unit with a methacrylic acid structure) directly bonded to the principal chain of the resin (HR) is not included in the side-chain CH3 partial structure according to the present invention, since the contribution thereof to the surface

localization of the resin (HR) is slight due to the influence of the principal chain.

In particular, when the resin (HR) comprises, for example, a repeating unit derived from a monomer containing a polymerizable moiety having a carbon- carbon double bond, such as any of repeating units of general formula (M) below, and when each of R-_i to R^ is CH3 "per se," the CH3 is not included in the CH3 partial structure contained in a side chain portion according to the present invention.

In contrast, a CH3 partial structure arranged via some atom apart from the C-C principal chain

corresponds to the_ sj.de-chain CH3 pariial. structure according to the present invention. For example, when R_]_ is an ethyl group (CH2CH3) , it is stated that "one" side-chain CH3 partial structure according to the present invention is contained.

R 1 1 R-I 3

CM)

R ₁₂ R-| 4

general formula (M) above, each of Rn to R]_4 independently represents a side chain portion.

Each of Rii to R^4 as a side chain portion

represents a hydrogen atom, a monovalent organic group or the like.

As the monovalent organic group represented by each of R]_]_ to R , there can be mentioned an alkyl group, a cycloalkyl group, an aryl group,, an

alkyloxycarbonyl group, a cycloalkyloxycarbonyl group, an aryloxycarbonyl group, an alkylaminocarbonyl group, a cycloalkylaminocarbonyl group, an arylaminocarbonyl group or the like. Substituents may further be ^' introduced in these groups.

It is preferred for the hydrophobic resin (HR) to be a resin comprising a repeating unit containing a CH3 partial structure in its side chain portion. More preferably, the hydrophobic resin (HR) comprises, as such a repeating unit, at least one repeating unit (x) selected from among the repeating units of general formula (II) below and repeating units of general formula (III) below.

The repeating units of general formula (II) will be described in detail below.

(II) In general formula (II) above, X^i represents a hydrogen atom, an alkyl group, a cyano group or a halogen atom. ]¾ represents an organic group having at least one CH3 partial structure and being stable against acids. Herein, in particular, it is preferred for the organic group stable against acids to be an organic group not containing "any group that when acted on by an acid, is decomposed to thereby produce a polar group" described above in connection with the resin (A) -

The alkyl group represented by Χ^χ is preferably one having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, a propyl group, a hydroxymethyl group or a trifluoromethyl group. A methyl group is more preferred.

Preferably, is a hydrogen atom or a methyl group.

As R2, there can be mentioned an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, an aryl group and an aralkyl group each

containing at least one CH3 partial structure. An alkyl group as a substituent may further be introduced in each of the cycloalkyl group, alkenyl group,

cycloalkenyl group, aryl group and aralkyl group.

R2 is preferably an alkyl group or alkyl- substituted cycloalkyl group containing at least one CH3 partial structure. The organic group stable against acids containing at least one CH3 partial structure represented by R2 preferably contains 2 to 10 CH3 partial structures, more preferably 2 to 8 CH3 partial structures.

The alkyl group containing at least one CH3 partial structure represented by R2 is preferably a branched alkyl group having 3 to 20 carbon atoms. As preferred alkyl groups, there can be mentioned, for example, an isopropyl group, an isobutyl group, a t- butyl group, a 3-pentyl group, a 2-methyl-3-butyl group, a 3-hexyl group, a 2-methyl-3-pentyl group, a 3- methyl-4-hexyl group, a 3, 5-dimethyl- -pentyl group, an isooctyl group, a 2 , 4 , 4-trimethylpentyl group, a 2- ethylhexyl group, a 2 , 6-dimethylheptyl group, a 1,5- dimethyl-3-heptyl group, a 2 , 3 , 5 , 7-tetramethyl-4-heptyl group and the like. An isobutyl group, a t-butyl group, a 2-methyl-3-butyl group, a 2-methyl-3-pentyl group, a 3-methyl-4-hexyl group, a 3, 5-dimethyl-4- pentyl group, a 2 , 4 , 4-trimeth_yJ ₁ pejityJ^g oja_,_a_2 __ ethylhexyl group, a 2 , 6-dimethylheptyl group, a 1,5- dimethyl-3-heptyl group and a 2, 3, 5, 7-tetramethyl-4- heptyl group are more preferred.

The cycloalkyl group containing at least one CH3 partial structure represented by R2 may be monocyclic or polycyclic. In particular, there can be mentioned groups with, for example, monocyclo, bicyclo, tricyclo and tetracyclo structures each having 5 or more carbon atoms, preferably 6 to 30 carbon atoms and most

preferably 7 to 25 carbon atoms. As preferred

cycloalkyl groups, there can be mentioned an adamantyl group, a noradamantyl group, a decalin residue, a tricyclodecanyl group, a tetracyclododecanyl group, a norbornyl group, a cedrol group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecanyl group and a cyclododecanyl group. As more preferred cycloalkyl groups, there can be mentioned an adamantyl group, a norbornyl group, a cyclohexyl group, a cyclopentyl group, a

tetracyclododecanyl group and a tricyclodecanyl group. A norbornyl group, a cyclopentyl group and a cyclohexyl group are further more preferred.

The alkenyl group containing at least one CH3 partial structure represented by R2 is preferably a linear or branched alkenyl group having 1 to 20 carbon atoms. A branched alkenyl group is more preferred.

The aryl group containing _^ a.t _J _L ea^_on^._CH_3..._P-.a.r_ti.a.l, structure represented by R2 is preferably an aryl group having 6 to 20 carbon atoms, such as a phenyl group or a naphthyl group. A phenyl group is more preferred.

The aralkyl group containing at least one CH3 partial structure represented by ]¾ is preferably one having 7 to 12 carbon atoms. For example, there can be mentioned a benzyl group, a phenethyl group, a

naphthylmethyl group or the like. Examples of hydrocarbon groups each containing two or more CH3 partial structures represented by R2 include an isopropyl group, an isobutyl group, a t- butyl group, a 3-pentyl group, a 2-methyl-3-butyl group, a 3-hexyl group, a 2 , 3-dimethyl-2-butyl group, a 2-methyl-3-pentyl group, a 3-methyl-4-hexyl group, a

3.5-dimethyl-4-pentyl group, an isooctyl group, a

2 , 4 , 4-trimethylpentyl group, a 2-ethylhexyl group, a

2.6-dimethylheptyl group, a 1 , 5-dimethyl-3-heptyl group, a 2, 3, 5, 7-tetramethyl-4-heptyl group, a 3,5- dimethylcyclohexyl group, a 3 , 5-di-tert-butylcyclohexyl group, a 4-isopropylcyclohexyl group, a 4-t- butylcyclohexyl group, an isobornyl group and the like. An isobutyl group, a t-butyl group, a 2-methyl-3-butyl group, a 2 , 3-dimethyl-2-butyl group, a 2-methyl-3- pentyl group, a 3-methyl-4-hexyl group, a 3 , 5-dimethyl- -4-pentyl group, a 2, 4, -trimethylpentyl group, a 2- ethylhexyl group, a 2 , 6-dimethylheptyl group, a 1,5- dimethyl-3-heptyl group, a 2, 3, 5, 7-tetramethyl-4-heptyl group, a 3, 5-dimethylcyclohexyl group, a 3, 5-di-tert- butylcyclohexyl group, a 4-isopropylcyclohexyl group, a 4-t-butylcyclohexyl group and an isobornyl group are more preferred.

Preferred particular examples of the repeating units of general formula (II) are shown below, which in no way limit the scope of the present invention.

It is preferred for the repeating units of general formula (II) to be those stable against acids (non- acid-decomposable) , in particular, repeating units containing no groups that are decomposed under the action of an acid to thereby produce polar groups.

The repeating units of general formula (III) will be described in detail below.

(III)

In general formula (III) above, X]~,2 represents a hydrogen atom, an alkyl group, a cyano group or a halogen atom. R3 represents an organic group having at least one CH3 partial structure and being stable against acids; and n is an integer of 1 to 5.

The alkyl group represented by is preferably one having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, a propyl group, a hydroxymethyl group or a trifluoromethyl group. A methyl group is more preferred.

Preferably, Xj-,2 ^{1S a} hydrogen atom.

R3 is an organic group stable against acids. In particular, R3 is preferably an organic group not containing "any group that when acted on by an acid, is decomposed to thereby produce a polar group" described above in connection with the resin (A) .

As R3, there can be mentioned an alkyl group containing at least one CH3 partial structure.

The organic group stable against acids containing at least one CH3 partial structure represented by R3 preferably contains 1 to 10 CH3 partial structures, more preferably 1 to 8 CH3 partial structures and further more preferably 1 to 4 CH3 partial structures. The alkyl group containing at least one CH3 partial structure represented by R3 is preferably a branched alkyl group having 3 to 20 carbon atoms. As preferred alkyl groups, there can be mentioned, for example, an isopropyl group, an isobutyl group, a t- butyl group, a 3-pentyl group, a 2-methyl-3-butyl group, a 3-hexyl group, a 2-methyl-3-pentyl group, a.3- methyl-4-hexyl group, a 3 , 5-dimethyl-4-pentyl group, an isooctyl group, a 2 , 4 , 4-trimethylpentyl group, a 2- ethylhexyl group, a 2 , 6-dimethylheptyl group, a 1,5- dimethyl-3-heptyl group, a 2, 3, 5, 7-tetramethyl-4-heptyl group and the like. An isobutyl group, a t-butyl group, a 2-methyl-3-butyl group, a 2-methyl-3-pentyl group, a 3-methyl-4-hexyl group, a 3, 5-dimethyl-4- pentyl group, a 2 , 4 , 4-trimethylpentyl group, a 2- ethylhexyl group, a 2 , 6-dimethylheptyl group, a 1,5- dimethyl-3-heptyl group and a 2 , 3 , 5 , 7-tetramethyl-4- heptyl group are more preferred.

Examples. of alkyl groups each containing two or more CH3 partial structures represented by R3 include an isopropyl group, an isobutyl group, a t-butyl group, a 3-pentyl group, a 2 , 3-dimethylbutyl group, a 2- methyl-3-butyl group, a 3-hexyl group, a 2-methyl-3- pentyl group, a 3-methyl-4-hexyl group, a 3, 5-dimethyl- 4-pentyl group, an isooctyl group, a 2,4,4- trimethylpentyl group, a 2-ethylhexyl group, a 2,6- dimethylheptyl group, a 1 , 5-dimet.hyi-3-hept;y L group, a 2, 3, 5, 7-tetramethyl-4-heptyl group and the like. Alkyl groups having 5 to 20 carbon atoms are preferred, including an isopropyl group, a t-butyl group, a 2- methyl-3-butyl group, a 2-methyl-3-pentyl group, a 3- methyl-4-hexyl group, a 3, 5-dimethyl-4-pentyl group, a 2 , 4 , 4-trimethylpentyl group, a 2-ethylhexyl group, a 2 , 6-dimethylheptyl group, a 1 , 5-dimethyl-3-heptyl group and a 2 , 3 , 5 , 7-tetramethyl-4-heptyl group are more preferred.

In the formula, n is an integer of 1 to 5, preferably 1 to 3, and more preferably 1 or 2.

Preferred particular examples of the repeating units of general formula (III) are shown below, which in no way limit the scope of the present invention.

It is preferred for the repeating units of general formula (III) to be those stable against acids (non- acid-decomposable) , in particular, repeating units containing no groups that are decomposed under the action of an acid to thereby produce polar groups.

When the resin (HR) contains a CH3 partial

structure in its side chain portion and contains neither a fluorine atom nor a silicon atom, the content of at least one repeating unit (x) selected from among the repeating units of general formula (II) and repeating units of general formula (III) based on all the repeating units of the. resin (HR) is preferably 90 mol% or more, more preferably 95 mol% or more. The content based on all the repeating units of the resin (HR) is generally 100 mol% or less.

When the resin (HR) contains at least one

repeating unit (x) selected from among the repeating units of general formula (II) and repeating units of general formula (III) in an amount of 90 mol% or more based on all the repeating units of the resin (HR) ,_the surface free energy of the resin (HR) is increased. As a result, the localization of the resin (HR) in the surface of the resist film is promoted, so that the static/dynamic contact angle of the resist film with respect to water can be securely increased, thereby enhancing the immersion liquid tracking property.

In. the instance of containing a fluorine atom and/or a silicon atom (i) and also in the instance of containing a CH3 partial structure in _^ its _^ side chain_ (ii) , the hydrophobic resin (HR) may contain at least one group selected from among the following groups (x) to (z) .

Namely,

(x) an acid group,

(y) a group with a lactone structure, an acid anhydride group or an acid imido group, and

(y) a group that when acted on by an acid, is decomposed .

As the acid group (x) , there can be mentioned a phenolic hydroxyl group, a carboxylic acid group, a fluoroalcohol group, a sulfonic acid group, a

sulfonamido group, a sulfonimido group, an

(alkylsulfonyl) (alkylcarbonyl ) methylene group, an

(alkylsulfonyl) (alkylcarbonyl ) imido group, a

bis (alkylcarbonyl)methylene group, a

bis (alkylcarbonyl) imido group, a

bis (alkylsulfonyl ) methylene group, a

bis ( alkylsulfonyl ) imido group, a

tris (alkylcarbonyl) methylene group or a

tris (alkylsulfonyl) methylene group or the like.

As preferred acid groups, there can be mentioned a fluoroalcohol group, a sulfonimido group and a

bis (alkylcarbonyl ) methylene group. As a preferred fluoroalcohol group, there can be mentioned a

hexafluoroisopropanol group.

The repeating unit containing an acid group (x) is, for example, a repeating unit wherein the acid group is directly bonded to the principal chain of a resin, such as a repeating unit derived from acrylic acid or methacrylic acid. Alternatively, this

repeating unit may be a repeating unit wherein the acid group is bonded via a connecting group to the principal chain of a resin. Still alternatively, this repeating unit may be a repeating unit wherein the acid group .is introduced in a terminal of the resin by using a chain transfer agent or polymerization initiator containing the acid group in the stage of polymerization. The repeating unit containing an acid group (x) may have at least either a fluorine atom or a silicon atom.

The content of the repeating unit containing an acid group (x) based on all the repeating units of the hydrophobic resin (HR) is preferably in the range of 1 to 50 mol%, more preferably 3 to 35 mol% and further more preferably 5 to 20 mol%.

Particular examples of the repeating units each containing an acid group (x) are shown below. In the formulae, Rx represents a hydrogen atom, CH3, CF3 or CH ₂ 0H.

110

Among the group with a lactone structure, acid anhydride group and acid imido group (y) , the group with a lactone structure is especially preferred.

The repeating unit containing any of these groups is, for example, a repeating unit wherein the group is directly bonded to the principal chain of a resin, such as a repeating unit derived from an acrylic ester or a methacrylic ester. Alternatively, this repeating unit may be a repeating unit wherein the group is bonded via a connecting group to the principal chain of a resin. Still alternatively, this repeating unit may be a repeating unit wherein the group is introduced in a terminal of the resin by using a chain transfer agent or polymerization initiator containing the group in the stage of polymerization.

As the repeating unit containing a group with a lactone structure, there can be mentioned, for example, any of the same repeating units with lactone structures

decomposable resin (A) .

The content of repeating unit containing a group with a lactone structure, an acid anhydride group or an acid imido group, based on all the repeating units of the hydrophobic resin (HR) , is preferably in the range of 1 to 100 mol%, more preferably 3 to 98 mol% and further more preferably 5 to 95 mol%.

As the repeating unit containing a group (z) decomposable under the action of an acid introduced in the hydrophobic resin ( HR ) , there can be mentioned any of the same repeating units containing acid- decomposable groups as set forth above in connection with the resin (A) . The repeating unit having a group

(z) decomposed under the action of an acid may contain at least either a fluorine atom or a silicon atom. The content of repeating unit having a group (z) decomposed under the action of an acid in the hydrophobic resin

( HR ) , based on all the repeating units of the

hydrophobic resin ( HR ) , is preferably in the range of 1 to 80 mol%, more preferably 10 to 80 mol% and further more preferably 20 to 60 mol%.

The hydrophobic resin ( HR ) may further contain any of the repeating units represented by general

formula (V) below.

In general formula (V) ,

Rc31 represents a hydrogen atom, an alkyl group, an alkyl group optionally substituted with one or more fluorine atoms, a cyano group or a group of the

formula ~CH2~0- R _ac 2 in which R _ac 2 represents a hydrogen atom, an alkyl group or an acyl group. R _Q 31 is

preferably a hydrogen atom, a methyl group, a hydroxyraethyl group, or a trifluoromethyl group, more preferably a hydrogen atom or a methyl group.

R _c 32 represents a group containing an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, or an aryl group. These groups may be

substituted with fluorine atom and/or silicon atom.

L _c 3 represents a single bond or a bivalent

connecting group.

In general formula (V) , the alkyl group

represented by R _c 32 is preferably a linear or branched alkyl group having 3 to 20 carbon atoms.

The cycloalkyl group is preferably a cycloalkyl group having 3 to 20 carbon atoms.

The alkenyl group is preferably an alkenyl group having 3 to 20 carbon atoms.

The cycloalkenyl group is preferably a

cycloalkenyl group having 3 to 20 carbon atoms.

The aryl group is preferably an aryl group having

6 to 20 carbon atoms . A__p_h^nyJ _^ group_._and__a_n.aph.th-y_l-- group are more preferred. Substituents may be

introduced therein.

Preferably, R _c 32 represents an unsubstituted alkyl group or an alkyl group substituted with a fluorine atom.

The bivalent connecting group represented by L _c 3 is preferably an alkylene group (preferably having 1 to 5 carbon atoms), an ether bond, a phenylene group or an ester bond (group of the formula -C00-) .

The content of repeating unit expressed by general formula (V) , based on all the repeating units of the hydrophobic resin, is preferably in the range of 1 to 100 mol%, more preferably 10 to 90 mol% and further more preferably 30 to 70 mol%.

The hydrophobic resin (HR) may further contain any of the repeating units represented by general

formula (CII-AB) below.

(C I I - AB)

In formula (CII-AB) ,

each of R _c i] and R _c i2' independently represents a hydrogen atom, a cyano group, a halogen atom or an alkyl group.

Zc' represents an atomic group required for forming an alicyclic structure in cooperation with two carbon atoms (C-C) to which _c n _' and R _c i2' ^are

respectively bonded.

The content of repeating unit expressed by general formula (CII-AB) , based on all the repeating units of the hydrophobic resin, is preferably in the range of 1 to 100 moll, more preferably 10 to 90 mol% and further more preferably 30 to 70 mol%.

Specific examples of the repeating unit

represented by general formulae (V) or (CII-AB) will be shown below, which however in no way limit the scope of the present invention. In the formulae, Ra represents

H, CH ₃ , CH ₂ OH, CF ₃ or CN .

When the hydrophobic resin (HR) contains a

fluorine atom, the content of fluorine atom(s) is preferably in the range of 5 to 80 mass%, more

preferably 10 to 80 mass%, based on the weight average molecular weight of the hydrophobic resin. The content of the repeating unit containing a fluorine atom is preferably in the range of 10 to 100 mol%, more

preferably 30 to 100 mol%, based on all the repeating units of the hydrophobic resin (HR) .

When the hydrophobic resin (HR) contains a silicon atom, the content of silicon atom(s) is preferably in the range of 2 to 50 mass%, more preferably 2 to

30 mass%, based on the weight average molecular weight of the hydrophobic resin. The content of the repeating unit containing a silicon atom is preferably in the range of 10 to 100 mol%, more preferably 20 to

100 mol%, based on all the repeating units of the hydrophobic resin (HR) .

Meanwhile, when the resin (HR) contains a CH3 partial structure in its side chain portion, an

embodiment in which the resin (HR) contains

substantially none of fluorine and silicon atoms is preferred. In that instance, in particular, the content of repeating unit containing a fluorine atom or a silicon atom based on all the repeating units of the resin (HR) is preferably 5 mol% or less, more

preferably 3 mol% or less, further more preferably 1 mol% or less, and ideally 0 mol%, namely, containing none of fluorine and silJ-:on„_a_to_ms,. Mo.r_e_Qjzier_, ί±_i.s_ preferred for the resin (HR) to be comprised of

substantially only a repeating unit comprised of only an atom(s) selected from among a carbon atom, an oxygen atom, a hydrogen atom, a nitrogen atom and a sulfur atom. In particular, the content of repeating unit comprised of only an atom(s) selected from among a carbon atom, an oxygen atom, a hydrogen atom, a

nitrogen atom and a sulfur atom based on all the repeating units of the resin (HR) is preferably 95 mol% or more, more preferably 97 mol% or more, further more preferably 99 mol% or more, and ideally 100 mol%.

The weight average molecular weight of the hydrophobic resin (HR) in terms of standard polystyrene molecular weight is preferably in the range of 1000 to 100,000, more preferably 1000 to 50,000 and still more preferably 2000 to 15,000.

The hydrophobic resin (HR) may be used either individually or in combination.

The content of the hydrophobic resin (HR) in the composition is preferably in the range or 0.01 to

10 massl, more preferably 0.05 to 8 mass% and still more preferably 0.1 to 5 massl based on the total solid of the composition of the present invention.

In the hydrophobic resin (HR) , impurities, such as metals, .should naturally be of low quantity as in the resin (A) . The content of residual monomers and oligomer_components _^ _is_p_referjabj _^ y_iji_Jthe__.r_a ge. of 0.01 to 5 massl, more preferably 0.01 to 3 mass% and further more preferably 0.05 to 1 massl. If so, there can be obtained an actinic-ray- or radiation-sensitive resin composition being free from any in-liquid foreign matter and a change of sensitivity, etc. over time. From the viewpoint of resolution, resist shape, side wall of resist pattern, roughness, etc., the molecular weight distribution (Mw/Mn, also referred to as polydispersity index) thereof is preferably in the range of 1 to 5, more preferably 1 to 3 and further more preferably 1 to 2.

A variety of commercially available products can be used as the hydrophobic resin (HR) . Alternatively, the hydrophobic resin (HR) can be synthesized in accordance with routine methods (for example, radical polymerization) . As general synthesizing methods, there can be mentioned, for example, a batch

polymerization method in which a monomer species and an initiator are dissolved in a solvent and heated to thereby carry out polymerization, a dropping

polymerization method in which a solution of monomer species and initiator is dropped into a heated solvent over a period of 1 to 10 hours, etc. The dropping polymerization method is preferred.

The reaction solvent, polymerization initiator, reaction conditions (temperature, concentration, etc.) and purification method after re_a,c_t.i.o.n—are—th.e_same— s- described above in connection with the resin (A) . In the synthesis of the hydrophobic resin (HR) , it is preferred for the concentration condition of the reaction to be in the range of 30 to 50 mass%.

Specific examples of the hydrophobic resin (HR) will be shown below. The following Table 1 shows the molar ratio of individual repeating units

(corresponding to individual repeating units in order from the left), weight average molecular weight, and degree of dispersal with respect to each of the resins

(HR-26)

(HR-36) (HR-37)

34) (HR-35)

(HR-45) (HR-46) (HR-47

(HR-48)

(HR- 9) (HR-SO) (HR-51)

(HR-52) (HR-53) (HR-54)

(HR-58) (HR-59)

(HR-78) (HR-79) (HR-80) (HR-81) W

125

Table 1

(Continued) Table :

Resin Comp. ratio Mw M /Mn

HR-36 50/50 6000 1.5

HR-37 50/50 5000 1.6

HR-38 50/50 4000 1.4

HR-39 20/80 6000 1.4

HR-40 50/50 7000 1.4

HR-41 50/50 6500 1.6

HR-42 50/50 5200 1.6

HR-43 50/50 6000 1.4

HR-44 70/30 5500 1.6

HR-45 50/20/30 4200 1.4

HR-46 30/70 7500 1.6

HR-47 40/58/2 4300' 1.4

HR-48 50/50 6800 1.6

HR-49 100 6500 1.5

HR-50 50/50 6600 1.6

HR-51 30/20/50 6800 1.7

HR-52 95/5 5900 1.6

HR-53 40/30/30 4500 1.3

HR-54 50/30/20 6500 1.8

HR-55 30/40/30 7000 1.5

HR-56 60/40 5500 1.7

HR-57 40/40/20 4000 1.3

HR-58 60/40 3800 1.4

HR-59 80/20 7400 1.6

HR-60 40/40/15/5 4800 1.5

HR-61 60/40 5600 1.5

HR-62 50/50 5900 2.1

HR-63 80/20 7000 1.7

HR-64 100 5500 1.8

HR-65 50/50 9500 1.9

(Continued) Table :

Resin Comp. ratio Mw Mw/Mn

HR-66 50/50 9600 1.74

HR-67 60/40 34500 1.43

HR-68 30/70 19300 1.69

HR-69 10/90 26400 1.41

HR-70 100 27600 1.87

HR-71 80/20 4400 1.96

HR-72 100 16300 1.83

HR-73 5/95 24500 1.79

HR-74. 20/80 15400 1.68

HR-75 50/50 23800 1.46

HR-76 100 22400 1.57

HR-77 10/90 21600 1.52

HR-78 100 28400 1.58

HR-79 50/50 16700 1.82

HR-80 100 23400 1.73

HR-81 60/40 18600 1.44

HR-82 80/20 12300 1.78

HR-83 40/60 18400 1.58

HR-84 70/30 12400 1.49

HR-85 50/50 23500 1.94

HR-86 10/90 7600 1.75

HR-87 5/95 14100 1.39

HR-88 50/50 17900 1.61

HR-89 10/90 24600 1.72

HR-90 50/40/10 23500 1.65

HR-91 60/30/10 13100 1.51

HR-92 50/50 21200 1.84

HR-93 10/90 19500 1.66

(Continued) 12.9

[5] Basic compound

[5-1] Basic compound and ammonium salt compound (N) that when exposed to actinic rays or radiation, exhibit lowered basicity

It is preferred for the actinic-ray- or radiation- sensitive resin composition of the present invention to contain a basic compound or ammonium salt compound (hereinafter also referred to as a "compound (N)") that when exposed to actinic rays or radiation, exhibits a lowered basicity.

It is preferred for the compound (N) to be a compound (N-l) containing a basic functional group or ammonium group together with a group that when exposed to actinic rays or radiation, produces an acid

functional group. Namely, it is preferred for the compound (N) to be a basic compound containing a basic functional group together with a group that when exposed to actinic rays or radiation, produces an acid functional group, or an ammonium salt compound

containing an ammonium group together with a group that when exposed to actinic rays or radiation, produces an acid functional group.

As an example thereof, there can be mentioned a compound comprised of a salt formed by an onium cation and an anion resulting from the leaving of a proton from the acid functional group of a compound containing a_ bas_ic_ functional group or ammonium qroup, together with an acid functional group.

As the basic functional group, there can be mentioned, for example, an atomic group comprising the structure of a crown ether, a primary to tertiary amine, a nitrogen-containing heterocycle (pyridine, imidazole, pyrazine or the like) or the like. As preferred structures of the ammonium groups, there can be mentioned, for example, atomic groups comprising the structures of a primary to tertiary ammonium,

pyridinium, imidazolinium and pyrazinium and the like. The basic functional group is preferably a functional group containing a nitrogen atom, more preferably a structure containing a primary to tertiary amino group or a nitrogen-containing heterocyclic structure. In these structures, from the viewpoint of basicity increase, it is preferred for all the atoms adjacent to the nitrogen atom contained in each of the structures to be carbon atoms or hydrogen atoms. Further, from the viewpoint of basicity increase, it is preferred to avoid the direct bonding of electron-withdrawing functional groups (a carbonyl group, a sulfonyl group, a cyano group, a halogen atom, etc.) to nitrogen atoms.

As the acid functional group, there can be

mentioned, ^" for example, a carboxylic acid group, a sulfonic acid group or any of groups with the structure -X-NH-X- (X is CO or S0 ₂ ) .

As the onii^cation _L __there_._c.an_.be mentioned, for example, a sulfonium cation or an iodonium cation. In particular, there can be mentioned, for example, those described above as cation moieties in general formulae (ZI) and (ZII) for the acid generators (B) .

As compounds each exhibiting a lowered basicity, produced by the decomposition of compound (N) or compound (N-l) upon exposure to actinic rays or

radiation, there can be mentioned the compounds of general formulae (PA-I), (PA-II) and (PA-III) below. The compounds of general formulae (PA-II) and (PA-III) are especially preferred from the viewpoint of the higher-order simultaneous attainment of excellent effects concerning L R, local uniformity of pattern dimension and DOF.

First, the compounds of general formula (PA-I) will be described.

Q-A]_- (X) n-B-R (PA-I)

In general formula (PA-I),

A]_ represents a single bond or a bivalent

connecting group.

Q represents -SO3H or -CO2H. Q corresponds to the acid functional group produced upon exposure to actinic rays or radiation.

X represents -SO2- or -CO-, and

n is 0 or 1.

B represents a single bond, an oxygen atom

or -N(Rx)-.

Rx represents a hydrogen atom or a monovalent organic group.

R represents a monovalent organic group containing a basic functional group or a monovalent organic group containing an ammonium group.

The bivalent connecting group represented by A _] _ is preferably a bivalent connecting group having 2 to 12 carbon atoms. As such, there can be mentioned, for example, an alkylene group, a phenylene group or the like. An alkylene group containing at least one fluorine atom is more preferred, which has preferably 2 to 6 carbon atoms, more preferably 2 to 4 carbon atoms. A connecting group, such as an oxygen atom or a sulfur atom, may be introduced in the alkylene chain. In particular, an alkylene group, 30 to 100% of the hydrogen atoms of which are substituted with fluorine atoms, is preferred. It is more preferred for the carbon atom bonded to the Q-moiety to have a fluorine atom. Further, perfluoroalkylene groups are preferred. A perfluoroethylene group, a perfluoropropylene group and a perfluorobutylene group are more preferred.

The monovalent organic group represented by Rx preferably has 4 to 30 carbon atoms. As such, there can be mentioned, for example, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkenyl group or the like.

A substituent may be introduced in the alkyl group represented by Rx. The alkyl group is preferably a linear or branched alkyl group having 1 to 20 carbon atoms. An oxygen atom, a sulfur atom or a nitrogen atom may be introduced in the alkyl chain.

As the substituted alkyl group, in particular, there can be mentioned a linear or branched alkyl group substituted with a cycloalkyl group (for example, an adamantylmethyl group, an adamantylethyl group, a cyclohexylethyl group, a camphor residue, or the like) .

A substituent may be introduced in the cycloalkyl group represented by Rx. The cycloalkyl group

preferably has 3 to 20 carbon atoms. An oxygen atom may be introduced in the ring.

A substituent may be introduced in the aryl group represented by Rx. The aryl group preferably has 6 to 14 carbon atoms.

A substituent may be introduced in the aralkyl group represented by Rx. The aralkyl group preferabl has 7 to 20 carbon atoms.

A substituent may be introduced in the alkenyl group represented by Rx. For example, there can be mentioned groups each resulting from the introduction of, a double bond at an arbitrary position of any of the alkyl groups mentioned above as being represented by Rx.

As preferred partial structures of the basic functional groups , _ther_e__can__ be mentioned, for example, the structures of a crown ether, a primary to tertiary amine and a nitrogen-containing heterocycle (pyridine, imidazole, pyrazine or the like) .

As preferred partial structures of the ammonium groups, there can be mentioned, for example, the structures of a primary to tertiary ammonium,

pyridinium, imidazolinium, pyrazinium and the like.

The basic functional group is preferably a functional group containing a nitrogen atom, more preferably a structure having a primary to tertiary amino group or a nitrogen-containing heterocyclic structure. In these structures, from the viewpoint of basicity increase, it is preferred for all the atoms adjacent to the nitrogen atom contained in each of the structures to be carbon atoms or hydrogen atoms.

Further, from the viewpoint of basicity increase, it is preferred to avoid the direct bonding of electron- withdrawing functional groups (a carbonyl group, a sulfonyl group, a cyano group, a halogen atom, etc.) to nitrogen atoms.

With respect to the monovalent organic group (R- group) containing any of these structures, the

monovalent organic group preferably has 4 to 30 carbon atoms. As such, there can be mentioned an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkenyl group or the ^* like. A substituent may be introduced in each of these groups.

The alkyl group, cycloalkyl group, aryl group, aralkyl group and alkenyl group contained in the alkyl group, cycloalkyl group,, aryl group, aralkyl group and alkenyl group each containing a basic functional group or an ammonium group, represented by R are the same as the alkyl group, cycloalkyl group, aryl group, aralkyl group and alkenyl group set forth above as being represented by Rx. As substituents that may be introduced in these groups, there can be mentioned, for example, a halogen atom, a hydroxyl group, a nitro group, a cyano group, a carboxyl group, a carbonyl group, a cycloalkyl group (preferably 3 to 10 carbon atoms), an aryl group

(preferably 6 to ^' 14 carbon atoms), an alkoxy group (preferably 1 to 10 carbon atoms) , an acyl group

(preferably 2 to 20 carbon atoms) , an acyloxy group (preferably 2 to 10 carbon atoms), an alkoxycarbonyl group (preferably 2 to 20 carbon atoms) ,_ an amijoacyl.__ group ^■ (preferably 2 to 20 carbon atoms) and the like. In the ring structure of the aryl group, cycloalkyl group, etc., further an alkyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms) can be mentioned as a substituent. With respect to the aminoacyl group, further one or two alkyl groups (each preferably 1 to 20 carbon atoms) can be mentioned as substituents .

When B is -N(Rx)-, it is preferred for R and Rx to be bonded to each other to thereby form a ring. When a ring structure is formed, the stability thereof is ^' enhanced, and thus the storage stability of the

composition containing the same is enhanced. The number of carbon atoms constituting the ring is

preferably in the range of- 4 to 20. The ring may be monocyclic or polycyclic, and an oxygen atom, a sulfur atom or a nitrogen atom may be introduced in the ring. As the monocyclic structure, there can be

mentioned a 4- to 8-membered ring containing a nitrogen atom, or the like. As the polycyclic structure, there can be mentioned structures each resulting from a combination of two, three or more monocyclic

structures. Substituents may be introduced in the monocyclic structure and polycyclic structure. As preferred substituents, there can be mentioned, for example, a halogen atom, a hydroxyl group, a cyano group, a carboxyl group, a carbonyl group, a cycloalkyl group (preferably 3 to 10 carbon atoms), an aryl group (preferably 6 to 14 carbon atoms) , an alkoxy group (preferably 1 to 10 carbon atoms) , an acyl group

(preferably 2 to 15 carbon atoms), an acyloxy group (preferably 2 to 15 carbon atoms) , an alkoxycarbonyl group (preferably 2 to 15 carbon atoms) , an aminoacyl group (preferably 2 to 20 carbon atoms) and the like. With respect to the ring structure in the aryl group, ^y^loalkyJL-¾r_ouiE),._ejtc _^ ,___fjarJ:_he_r__an__aLkyl—gro-up- (preferably 1 to 15 carbon atoms) can be mentioned as a substituent ^' . With respect to the aminoacyl group, further one or more alkyl groups (each preferably 1 to 15 carbon atoms) can be mentioned as substituents.

Among the compounds of general formula (PA-I), the compounds wherein the Q-moiety is sulfonic acid can be synthesized by using a common sulfonamidation reaction. For example, these compounds can be synthesized by a method in which one sulfonyl halide moiety of a

bissulfonyl halide compound is caused to selectively react with an amine compound to thereby form a

sulfonamide bond and thereafter the other sulfonyl halide moiety is hydrolyzed, or alternatively by a method in which a cyclic sulfonic anhydride is caused to react with an amine compound to thereby effect a ring opening.

Now, the compounds of general formula (PA-II) will be described.

Q ₁ -X ₁ -NH-X ₂ -Q2 (PA-II)

In general formula (PA-II),

each of Q]_ and Q_2 independently represents a monovalent organic group, provided that either or Q2 contains a basic functional group. and Q2 may be bonded to each other to thereby form a ring, the ring containing a basic functional group.

Each of X _] _ and X2 independently represents -CO- or

-so ₂ -.

In the formula, -NH- corresponds to the acid functional group produced upon exposure to actinic rays or radiation.

The monovalent organic group represented by each of Q]_ and Q2 in general formula (PA-II) preferably has 1 to 40 carbon atoms. As such, there can be mentioned, for example, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkenyl group or the like .

A substituent may be introduced in the alkyl group represented by each of Q]_ and Q2 · The alkyl group is preferably a linear or branched alkyl group having 1 to 30 carbon atoms. An oxygen atom, a sulfur atom or a nitrogen atom may be introduced in the alkyl chain.

A substituent may be introduced in the cycloalkyl group represented by each of and Q2. The cycloalkyl group preferably has 3 to 20 carbon atoms. An oxygen atom or a nitrogen atom may be introduced in the ring.

A substituent may be introduced in the aryl group represented by each of and Q2 · The aryl group preferably has 6 to 14 carbon atoms.

A substituent may be introduced in the aralkyl group represented by each of Q_ and Q2 · The aralkyl group preferably has 7 to 20 carbon atoms.

A substituent may be introduced in the alkenyl group represented by each of and Q2. For example, there can be mentioned groups each resulting from the introduction of a double bond at an arbitrary position of any of the above alkyl groups.

As substituents that may be introduced in these groups, there can be mentioned, for example, a halogen atom, a hydroxyl group, a nitro group, a cyano group, a carboxyl group, a carbonyl group, a cycloalkyl group (preferably 3 to 10 carbon atoms) , an aryl group

(preferably 6 to 14 carbon atoms) , an alkoxy group (preferably 1 to 10 carbon atoms), an acyl group

(preferably 2 to 20 carbon atoms), an acyloxy group (preferably 2 to 10 carbon atoms) , an alkoxycarbonyl group (preferably 2 to 20 carbon atoms) , an aminoacyl group (preferably 2 to 10 carbon atoms) and the like. With respect to the ring structure in the aryl group, cycloalkyl group, etc., further an alkyl group

(preferably 1 to 10 c.arbon atoms) can be mentioned as a substituent. With respect to the aminoacyl group, further an alkyl group (preferably 1 to 10 carbon atoms) can be mentioned as a substituent. As

substituted alkyl groups, there can be mentioned, for example, perfluoroalkyl groups, such as a

perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group and a perfluorobutyl group.

As preferred partial structures of the basic functional groups contained in at least either Q _] _ or Q2 _/ there can be mentioned those described above in coj e_cj^icm__with the basic funcJ:_i_Qnai groups cor.ta ir.ed— in R of general formula (PA-I) .

As the structure in which and <¾? are bonded to each other to thereby form a ring, the ring containing a basic functional group, there can be mentioned, for example, a structure in which the organic groups represented by Q]_ and Q2 are bonded to each other by an alkylene group, an oxy group, an imino group or the like . In general formula (PA-II), it is preferred for at least either X^ or X2 to be -SO2-.

Below, the compounds of general formula (PA-III) will be described.

Q ₁ -X ₁ -NH-X ₂ -A2- ( ^X 3)m-B-Q3 (PA-III)

In general formula (PA-III) ,

each of and Q3 independently represents a monovalent organic group, provided that either or Q3 contains a basic functional group. Q]_ and Q3 may be bonded to each other to thereby form a ring, the ring containing a basic functional group.

Each of X]_, X2 and X3 independently

represents -CO- or -SO2-.

A ₂ represents a bivalent connecting group.

B represents a single bond, an oxygen atom

or -N(Qx)-.

Qx represents a hydrogen atom or a monovalent organic group.

When B is -N(Qx)-, Q3 and Qx may be bonded to each other to thereby form a ring; and

m is 0 or 1.

In the formula, -NH- corresponds to the acid functional group produced upon exposure to actinic rays or radiation.

Q _] _ is as defined above in connection with general formula (PA-II) .

As the organic groups represented by Q3, there can be mentioned those set forth above as being represented by Q_ and Q2 in general formula (PA-II) .

As the structure in which Q and Q3 are bonded to each other to thereby form a ring, the ring containing a basic functional group, there can be mentioned, for example, a structure in which the organic groups represented by Q_ and Q3 are bonded to each other by an alkylene group, an oxy group, an imino group or the like.

The bivalent connecting group represented by A2 is preferably a bivalent connecting group having 1 to 8 carbon atoms in which a fluorine atom is introduced. As such, there can be mentioned, for example, an alkylene group having 1 to 8 carbon atoms in which a fluorine atom is introduced, a phenylene group in which a fluorine atom is introduced, or the like. An

alkylene group containing a fluorine atom is more preferred, which has preferably 2 to 6 carbon atoms, more preferably 2 to 4 carbon atoms. A connecting group, such as an oxygen atom or a sulfur atom, may be introduced in the alkylene chain. In particular, an alkylene group, 30 to 100% of the hydrogen atoms of which are substituted with fluorine atoms, is

preferred. Further, perfluoroalkylene groups are preferred. Perfluoroalkylene groups each having 2 to 4 carbon atoms are most preferred.

The monovalent organic group represented by Qx preferably has 4 to 30 carbon atoms. As such, there can be mentioned, for example, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkenyl group or the like. As the alkyl group, cycloalkyl group, aryl group, aralkyl group and alkenyl group, there can be mentioned those set forth above as being represented by Rx of general formula (PA-I).

In general formula (PA-III), it is preferred for each of X_, X2 and X3 to be -S02--

The compounds (N) are preferably sulfonium salt compounds from the compounds of general formulae (PA- I), (PA-II) and (PA-III) and iodonium salt compounds from the compounds of general formulae (PA-I), (PA-II) and (PA-III), more preferably the compounds of general formulae (PA1) and (PA2) below.

(PA 1 ) (PA2)

In general formula (PAl),

each of R'201' R' 202 ^anc ^ ^'203 independently represents an organic group. In particular, these are the same as R20I' ^R 202 ^anc * ^203 i ⁿ formula ZI mentioned above in connection with the component (B) .

X ^~ represents a sulfonate anion or carboxylate anion resulting from the leaving of a hydrogen atom from the -SO3H moiety or -C00H moiety of each of the compounds of general formula (PA-I), or an anion resulting from the leaving of a hydrogen atom from the -NH- moiety of each of the compounds of general formulae (PA-II) and (PA-III) .

In general formula (PA2) above,

each of R' 204 ^anc ^ R'205 independently represents an aryl group, an alkyl group or a cycloalkyl group. In particular, these are the same as R204 ^anc * ^R 205 i- ⁿ formula ZII mentioned above in connection with the component (B) .

X ^~ represents a sulfonate anion or carboxylate anion resulting from the leaving of a hydrogen atom from the -SO3H moiety or -COOH moiety of each of the compounds of general formula (PA-I), or an anion resulting from the leaving of a hydrogen atom from the -NH- moiety of each of the compounds of general formulae (PA-II) and (PA-III) .

The compounds (N) when exposed to actinic rays or

example, the compounds of general formulae (PA-I), (PA II) and (PA-III) .

Each of the compounds of general formula (PA-I) contains a sulfonic acid group or a carboxylic acid group together with a basic functional group or an ammonium group, so that it is a compound having its basicity lowered as compared with that of the compound (N) or dissipated, or having its basicity converted to acidity.

Each of the compounds of general formulae (PA-II) and (PA-III) contains an organic sulfonylimino group or an organic carbonylimino group together with a basic functional group, so that it is a compound having its basicity lowered as compared with that of the compound (N) or dissipated, or having its basicity converted to acidity .

In the present invention, the lowering of basicity upon exposure to actinic rays or radiation means that the acceptor properties for the proton (acid produced by exposure to actinic rays or radiation) of the compound (N) are lowered by exposure to actinic rays or radiation. The lowering of acceptor properties means that when an equilibrium reaction in which a

noncovalent-bond complex being a proton adduct is formed from a proton and a compound containing a basic functional group occurs, or when an equilibrium

reaction in which the counter cation of a compound containing an ammonium group is replaced by a proton occurs, the equilibrium constant of the chemical equilibrium is lowered.

When the compound (N) whose basicity is lowered upon exposure to actinic rays or radiation is contained in the resist film, in nonexposed areas, the acceptor properties of the compound (N) are fully exhibited, so that any unintended reaction between the acid diffused from exposed areas, etc. and the resin (A) can be suppressed. In exposed areas, the acceptor properties of the compound (N) are lowered, so that the intended reaction between the acid and the resin (A) occurs with high certainty. It is presumed that, by virtue of the contribution of this activity mechanism, a pattern excelling in line width roughness (LWR) , local

uniformity of pattern dimension, focus latitude (depth of focus DOF) and pattern shape can be obtained.

The basicity can be ascertained by performing pH measurement. Also, calculated values of basicity can be obtained by utilizing commercially available

software .

Particular examples of the compounds (N) that produce the compounds of general formula (PA-I) upon exposure to actinic rays or radiation are shown below, which in no way limit the scope of the present

invention .

These compounds can be easily synthesized from the compounds of general formula (PA-I), or a lithium, sodium or potassium salt thereof, and a hydroxide, bromide or chloride of iodonium or sulfonium, etc. by the salt exchange method described in Jpn. PCT National Publication No. Hll-501909 and JP-A-2003-246786. Also, the synthesis can be performed in accordance with the synthetic method described in JP-A-H7-333851.

Particular examples of the compounds (N) that produce the compounds of general formulae (PA-II) and (PA-III) upon exposure to actinic rays or radiation are shown below, which in no way limit the scope of the present invention. 

These compounds can be easily synthesized by using a common sulfonic-esterification reaction or

sulfonamidation reaction. For example, these compounds can be synthesized by a method in which one sulfonyl halide moiety of a bissulfonyl halide compound is caused to selectively react with, for example, an amine or alcohol containing the partial structure of general formula (PA-II) or (PA-III) to thereby form a

sulfonamide bond or a sulfonic ester bond and

thereafter the other sulfonyl halide moiety is

hydrolyzed, or alternatively by a method in which a cyclic sulfonic anhydride has its ring opened by an amine or alcohol containing the partial structure of general formula (PA-II). The above amine and alcohol each containing the partial structure of general formula (PA-II) or (PA-III) can be synthesized by causing an amine and an alcohol to react, in basic condition, with an anhydride, such as (R'C>2C)20 or (R'SC>2)20' or an acid chloride compound, such as.

RO2CCI or '302C1 (i he formulae, R' is a rr.ethyl group, an n-octyl group, a trifluoromethyl group or the like) . In particular, the synthesis can be performed in accordance with, for example, the synthetic examples of JP-A-2006-330098.

The molecular weight of the compounds (N) is preferably in the range of 500 to 1000.

It is optional for the actinic-ray- or

radiation-sensitive-- resin - composition of the present invention to contain the compounds (N) . When any of the compounds (N) is contained, the content thereof based on the total solids of the actinic-ray- or radiation-sensitive resin composition is preferably in the range of 0.1 to 20 mass%, more preferably 0.1 to 10 mass%.

[5-2] Basic compound (Ν' )

The actinic-ray- or radiation-sensitive resin composition of the present invention may contain a basic compound (N' ) different from the abo e_ compounds (N) so as to minimize any performance change over time from exposure to bake.

As preferred basic compounds ( ' ) , there can be mentioned the compounds having the structures of the following formulae (A) to (E) .

In general formulae (A) and (E) ,

R ²⁰⁰ , R201 _an d R202 _may b _e identical to or different from each other and each represent a hydrogen atom, an alkyl group (preferably having 1 to 20 carbon atoms) , a cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group (having 6 to 20 carbon atoms) . R201 _an d R202 _ma y j~, _e bonded to each other to thereby form a ring. R ²⁰³ , R ²⁰⁴ , R ²⁰⁵ and R ²⁰⁶ may be identical to or different from each other and each represent an alkyl group having 1 to 20 carbon atoms.

With respect to these alkyl groups, as a preferred substituted alkyl group, there can be mentioned an aminoalkyl group having 1 to 20 carbon atoms, a

hydroxyalkyl group having 1 to 20 carbon atoms or a cyanoalkyl group having 1 to 20 carbon atoms.

More preferably, the alkyl groups in general formulae (A) and (E) are unsubstituted .

As preferred compounds, there can be mentioned guanidine, aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine, an aminoalkylmorpholine, piperidine and the like. As more preferred compounds, there can be mentioned compounds with an imidazole structure, a diazabicyclo structure, an onium hydroxide structure, an onium carboxylate structure, a

trialkylamine structure, an aniline structure or a pyridine structure, alkylamine derivatives containing a hydroxyl group and/or an ether bond, aniline

derivatives containing a hydroxyl group and/or an ether bond, and the like.

As the compounds with an imidazole structure, there can be mentioned imidazole, 2,4,5- triphenylimidazole, benzimidazole, 2- phenylbenzimidazole and the like. As the compounds with a diazabicyclo structure, there can be

mentioned 1, -diazabicyclo [2,2,2] octane,

1 , 5-diazabicyclo [4,3,0] non-5-ene, 1 , 8-diazabicyclo [ 5, 4 , 0 ] undec-7-ene and the like. As the compounds with an onium hydroxide structure, there can be mentioned a triarylsulfonium hydroxide, phenacylsulfonium hydroxide, and sulfonium hydroxides containing a 2-oxoalkyl group such as

triphenylsulfonium hydroxide, tris(t- butylphenyl ) sulfonium hydroxide, bis (t- butylphe.nyl ) iodonium hydroxide, phenacylthiophenium hydroxide, 2-oxopropylthiophenium hydroxide and the like. As the compounds with an onium carboxylate structure, there can be mentioned those having the anion moiety of the compounds with an onium hydroxide structure replaced by a carboxylate, for example, an acetate, an adamantane-l-carboxylate, a perfluoroalkyl carboxylate and the like. As the compounds with a trialkylamine structure, there can be mentioned tri(n- butyl) amine, tri (n-octyl ) amine and the like. As the compounds with an aniline structure, there can be mentioned 2, 6-diisopropylaniline, N, N-dimethylaniline, N, N-dibutylaniline, N, N-dihexylaniline and the like. As the alkylamine derivatives containing a hydroxyl group and/or an ether bond, there can be mentioned ethanolamine, diethanolamine, triethanolamine,

tris (methoxyethoxyethyl ) amine,

tris (hydroxyethoxyethyl ) amine and the like. As the aniline derivatives containing a hydroxyl group and/or an ether bond, there can be mentioned N, N-bis (hydroxyethyl) aniline and the like.

As preferred basic compounds ( ' ) , there can be further mentioned an amine compound containing a phenoxy group, an ammonium salt compound containing a phenoxy group, an amine compound containing a sulfonic ester group and an ammonium salt compound containing a sulfonic ester group.

Each of the above amine compound containing a phenoxy group, ammonium salt compound containing a phenoxy group, amine compound containing a sulfonic ester group and ammonium salt compound containing a sulfonic ester group preferably contains at least one alkyl group bonded to the nitrogen atom thereof.

Further preferably, the alkyl group in its chain contains an oxygen atom, thereby forming an oxyalkylene group. The number of oxyalkylene groups in each molecule is one or more, preferably 3 to 9 and more preferably 4 to 6. Among the oxyalkylene groups, the structures of -CH ₂ CH ₂ 0-, -CH (CH ₃ ) CH ₂ 0- and -CH2CH2CH2O- are preferred.

As specific examples of the above amine compound containing a phenoxy group, ammonium salt compound containing a phenoxy group, amine compound containing a sulfonic ester group and ammonium salt compound

containing a sulfonic ester group, there can be

mentioned the compounds (Cl-1) to (C3-3) shown as examples in Section [0066] of U.S. Patent Application Publication No. 2007/0224539, which are however

nonlimiting.

As one of the basic compounds ( ' ) , use can be made of a nitrogen-containing organic compound

containing a group leaving under the action of an acid.

As an example of this compound, there can be mentioned any of compounds- of general formula (F) below. The compounds of general formula (F) below manifests an effective basicity in the system through the cleavage of the group leaving under the action of an acid.

In general formula (F), Ra, or each of Ra's independently, represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group or an aralkyl group. When n=2, two Ra's may be identical to or different from each other, and two Ra's may be bonded to each other to thereby form a bivalent heterocyclic hydrocarbon group (preferably up to 20 carbon atoms) or a derivative thereof.

Each of Rb' s independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group or an aralkyl group, provided that in the moiety - C(Rb) (Rb) (Rb) , when one or more Rb' s are hydrogen atoms, at least one of the remaining Rb's is a

cyclopropyl group or a 1-alkoxyalkyl group.

At least two Rb's may be bonded to each other to thereby form an alicyclic hydrocarbon group, an

aromatic hydrocarbon group, a heterocyclic hydrocarbon group or a derivative thereof.

In the formula, n is an integer of 0 to 2, and m is an integer of 1 to 3, provided that n+m=3.

In general formula (F) above, each of the alkyl groups, cycloalkyl groups, aryl groups and aralkyl groups represented by Ra and Rb may be substituted with a functional group, such as a hydroxyl group, a cyano group, an amino group, a pyrrolidino group, a

piperidino group, a morpholino group or an oxo group, as well as an alkoxy group or a halogen atom. With respect to the alkoxyalkyl group represented by Rb, the same substitution can be performed.

As the alkyl group, cycloalkyl group, aryl group and aralkyl group represented by Ra and/or Rb (these alkyl group, cycloalkyl group, aryl group and aralkyl group may be substituted with the above functional group, a1koxy_g[TOup_ r _^ halogen _^ atom)„^_ there can bo mentioned, for example,

a group derived from a linear or branched alkane, such as methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane, undecane or dodecane; a group as obtained by substituting the above alkane-derived group with at least one or at least one type of cycloalkyl group, such as a cyclobutyl group, a cyclopentyl group or a cyclohexyl group; a group derived from a cycloalkane, such as cyclobutane, cyclopentane, cyclohexane, cycloheptane , cyclooctane, norbornane, adamantane or noradamantane; a group as obtained by substituting the above

cycloalkane-derived group with at least one or at least one type of linear or branched alkyl group, such as a methyl group, an ethyl group, an n-propyl group, an i- propyl group, an n-butyl ^' group, a 2-methylpropyl group, a 1-methylpropyl group or a t-butyl group;

a group derived from an aromatic compound, such as benzene, naphthalene or anthracene; a group as obtained by substituting the above aromatic-compound-derived group with at least one or at least one type of linear or branched alkyl group, such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a 2-methylpropyl group, a 1-methylpropyl group or a t-butyl group;

a group derived from a heterocyclic compound, such as p rrolidin «5, _ip^rj__din_e,, morphol ine,- tetrahydrofuran, tetrahydropyran, indole, indoline, quinoline, perhydroquinoline, indazole or

benzimidazole ; a group as obtained by substituting the above heterocyclic-compound-derived group with at least one or at least one type of linear or branched alkyl group or aromatic-compound-derived group;

a group as obtained by substituting the above linear or branched-alkane-derived group or cycloalkane-derived group with at least one or at least one type of aromatic-compound-derived group, such as a phenyl group, a naphthyl group or an anthracenyl group; any of groups as obtained by substituting the above substituents with a functional group, such as a

hydroxyl group, a cyano group, an amino group, a pyrrolidine group, a piperidino group, a morpholino group or an oxo group; and the like.

Particular examples of. the basic compounds ( ' ) according to the present invention are shown below, which however in no way limit the scope of the present invention .

As the compounds of general formula (F) above, use can be made of commercially available products. They also may be synthesized from commercially available amines by the methods described in, for example,

Protective Groups in Organic Synthesis, the fourth edition. The most common synthetic method can be found in, for example, JP-A-2009-199021.

Moreover, as the basic compounds (N' ) , use can be made of compounds each containing a fluorine atom or a silicon atom and exhibiting basicity or increasing its basicity under the action of an acid, as described in JP-A-2011-141494. As particular examples of these compounds, there can be mentioned, for example, the compounds (B-7) to (B-18) used in Examples of the publication .

The molecular weight of the basic compounds (N' ) is preferably in the range of 250 to 2000, more preferably 400 to 1000. From the viewpoint of further lowering of LWR and local uniformity of pattern dimension, the molecular weight of the basic compounds is preferably 400 or greater, more preferably 500 or greater and further more preferably 600 or greater.

These basic compounds ( ' ) may be used in

combination with the above compounds (N) . Any one of the basic compounds (N' ) may be used alone, or two or more thereof may be used in combination.

It is optional for the actinic-ray- or radiation- sensitive resin composition of the present invention to contain any of the basic compounds (N' ) . When any of the basi_c_ compounds (N' ) isj_cmtaijie_d, the content- thereof is generally in the range of 0.001 to 10 massl, preferably 0.01 to 5 mass%, based on the total solids of the actinic-ray- or radiation-sensitive resin composition .

With respect to the ratio between acid generator and basic compound (comprising basic compound (N) and basic compound ( ' ) ) used in the composition, the molar ratio of acid generator/basic compound is preferably in the range of 2.5 to 300. Namely, a molar ratio of 2.5 or higher is preferred from the viewpoint of the enhancement of sensitivity and resolution. A molar ratio of 300 or below is preferred from the viewpoint of the inhibition of any resolution deterioration due to resist pattern thickening over time until baking treatment after exposure. The molar ratio of acid generator/basic . compound is more preferably in the range of 5.0 to 200, further more preferably 7.0 to 150.

[6] Surfactant

It is optional for the actinic-r-ay- or radiation- sensitive resin composition of the present invention to further contain a surfactant. When a surfactant is contained, it is preferred to .contain any one, or two or more, of fluorinated and/or siliconized surfactants (fluorinated surfactant, siliconized surfactant and surfactant containing both fluorine and silicon atoms) .

The actinic-ray- or radiation-sensitive resin composition of the present invention when containing the surfactant can, in the use of an exposure light source of 250 nm or below, especially 220 nm or below, produce a resist pattern of less adhesion and

development defects with favorable sensitivity and resolution.

As the fluorinated and/or siliconized surfactants, there can be mentioned those described in section [0276] of US Patent Application Publication

No. 2008/0248425. For example, there can be mentioned Eftop EF301 and EF303 (produced by Shin-Akita Kasei Co., Ltd.), Florad FC 430, 431 and 4430 (produced by Sumitomo 3M Ltd.), Megafac F171, F173, F176, F189, F113, F110, F177, F120 and R08 (produced by DIC

Corporation), Surflon S-382, SC101, 102, 103, 104, 105, 106 and KH-20 (produced by Asahi Glass Co., Ltd.), Troy Sol S-366 (produced by Troy Chemical Co., Ltd.), GF-300 and GF-150 (produced by TOAGOSEI CO., LTD.), Sarfron S- 393 (produced by SEIMI CHEMICAL CO., LTD.), Eftop

EF121, EF122A, EF122B, RF122C, EF125M, EF135M, EF351, EF352, EF801, EF802 and EF601 (produced by JEMCO INC.), PF636, PF656, PF6320 and PF6520 (produced by OMNOVA SOLUTIONS, INC.), and FTX-204G, 208G, 218G, 230G, 204D, 208D, 212D, 218D and 222D (produced by NEOS) . Further, polysiloxane polymer KP-341 (produced by Shin-Etsu Chemical Co., Ltd.) can be employed as a siliconized surfactant.

As the surfactant, besides the above publicly known surfactants, use can be made of a surfactant based on a polymer containing a fluoroaliphatic group derived from a fluoroaliphatic compound produced by a telomerization technique (also known as a telomer process) or an . oligomerization technique (also known as an oligomer process) . The fluoroaliphatic compound can be synthesized by the process described in JP-A-2002-90991.

As the relevant surfactants, there can be

mentioned Megafac F178, F-470, F-473, F-475, F-476 or F-472 (produced by DIC Corporation) , a copolymer from an acrylate (or methacrylate) containing a CgF _] _3 group and a poly (oxyalkylene) acrylate (or methacrylate), a copolymer from an acrylate (or methacrylate) containing a C3F7 group, poly (oxyethylene) acrylate (or

methacrylate) and poly ( oxypropylene ) acrylate (or methacrylate), and the like.

Moreover, in the present invention, use can be made of surfactants other than the fluorinated and/or siliconized surfactants, described in section [0280] of US Patent Application ^' Publication No. 2008/0248425.

These surfactants may be used either individually or in combination.

When the actinic-ray- or radiation-sensitive resin composition contains a surfactant, the amount of

2 mass%, more preferably 0.0005 to 1 mass%, based on the total mass of the actinic-ray- or radiation- sensitive resin composition (excluding the solvent) .

When the amount of surfactant added is controlled at 10 ppm or less based on the total mass of the actinic-ray- or radiation-sensitive resin composition (excluding the solvent) , the localization of the resin (HR) according to the present invention in the surface layer is promoted to thereby cause the surface of the resist film to be highly hydrophobic, so that the water tracking property in the stage of liquid-immersion exposure can be enhanced.

[7] Other additive

It is optional for the actinic-ray- or radiation- sensitive resin composition of the present invention to contain a carboxylic acid onium salt. As the

carboxylic acid onium salt, there can be mentioned any of those described in sections [0605] to [0606] of US Patent Application Publication No. 2008/0187860.

These carboxylic acid onium salts can be

synthesized by reacting a sulfonium hydroxide, an iodonium hydroxide or an ammonium hydroxide and a carboxylic acid with silver oxide in an appropriate solvent .

When the actinic-ray- or radiation-sensitive resin v

composition contains a carboxylic acid onium salt, the content thereof is geie^aJ-J ₁ y_J^_the_r^n5_e_o-f_0_. _^ l-_to. 20 mass%, preferably 0.5 to 10 mass% and further more preferably 1 to 7 mass%, based on the total solids of the composition.

According to necessity, the actinic-ray- or radiation-sensitive resin composition of the present invention may further contain a dye, a plasticizer, a photosensitizer , a light absorber, an alkali-soluble resin, a dissolution inhibitor, a compound capable of accelerating the dissolution in a developer (for example, a phenolic compound of 1000 or less ^' molecular weight, or a carboxylated alicyclic or aliphatic compound), etc.

The above phenolic compound of 1000 or less molecular weight can be easily synthesized by persons of ordinary skill in the art to which the present invention pertains while consulting the processes described in, for example, JP-A' s H4-122938 and H2- 28531, USP 4,916,210 and EP 219294.

As the carboxylated alicyclic or aliphatic compound, there can be mentioned, for example, a carboxylic acid derivative with a steroid structure such as cholic acid, deoxycholic acid or lithocholic acid, an adamantanecarboxylic acid derivative,

adamantanedicarboxylic acid, cyclohexanecarboxylic acid, cyclohexanedicarboxylic acid or the like. These are however nonlimiting.

From_ the _viewpjoint__ f _enhajxcJ.-n-g_t.h.e._r_es-0-l-V-i.ng- power, the actinic-ray- or radiation-sensitive resin composition of the present invention is preferably used in the form of a film whose thickness is in the range of 30 to 250 nm. More preferably, the film thickness is in the range of 30 to 200 nm. This film thickness can be attained by regulating the solid content of the composition within an appropriate range so as to cause the composition to have an appropriate viscosity, thereby improving the applicability and film forming property of the composition.

The solid concentration of the actinic-ray- or radiation-sensitive resin composition of the present invention is generally in the range of 1.0 to 10 mass%, preferably 2.0 to 5.7 mass% and more preferably 2.0 to 5.3 mass%. The resist solution can be uniformly applied onto substrates by regulating the solid

concentration so as to fall within this range.

Further, a resist pattern excelling in line width roughness can be formed by the regulation. Although the reason therefor is not necessarily apparent, it is presumed that very possibly, the aggregation of

materials, especially photoacid generators, in the resist solution can be inhibited by regulating the solid concentration so as to be 10 mass% or below, preferably 5.7 mass% or below, so that a uniform resist film can be formed.

The solid concentration refers to the percentage of the weight of non-solvent resist components based on the total weight of the actinic-ray- or radiation- sensitive resin composition.

The actinic-ray- or radiation-sensitive resin composition of the present invention is used in such a manner that the above-mentioned components are

dissolved in a given organic solvent, preferably the above-mentioned mixed solvent, and filtered and applied onto a given support (substrate) . The filter medium for use in the filtration is preferably one made of a polytetrafluoroethylene, polyethylene or nylon that has a pore size of 0.1 ym or less, preferably 0.05 μπι or less and more preferably 0.03 pm or less. In the filtration, as described in, for example, JP-A-2002- 62667, a cyclic filtration may be carried out, or two or more types of filters may be connected in series or parallel. Moreover, the composition may be filtered two or more times. Further, the composition may_be_ deaerated prior to and/or after the filtration.

<Method of forming pattern>

Now, the method of forming a pattern according to the present invention will be described.

The method of forming a pattern according to the present invention (negative pattern forming method) comprises at least the operations of:

(a) forming a film (resist film) comprising the actinic-ray- or radiation-sensitive resin composition of the present invention,

(b) exposing the film to actinic rays or

radiation, and

(c) developing the exposed film with a developer comprising an organic solvent.

In the operation (b) above, the exposure may be a liquid-immersion exposure.

In the pattern forming method of the present invention, the exposing operation (b) is preferably followed by a baking operation (d) .

The pattern forming method of the present

invention may further comprise an operation of

development using an alkali developer (e) .

In the pattern forming method of the present invention, the exposing operation (b) may be conducted two or more times.

In the pattern forming method of the present invention, the baking operation (d) may be conducted two or more times.

The resist film according to the present invention is one formed from the above actinic-ray- or radiation- sensitive resin composition of the present invention. In particular, the film is preferably one formed by coating a substrate with the actinic-ray- or radiation- sensitive resin composition. In the pattern forming method of the present invention, the operation of forming the fjJLm _^ jDf_;the_^cJ:inic^r^_y_rL_J3 -- adia-tion—- sensitive resin composition on a substrate, the

operation of exposing the film to light, and the operation of developing the exposed- film can be

performed using generally known methods.

Preferably, the operation of prebake (PB) is performed after the film formation but prior to the exposing operation.

Also preferably, the operation of post-exposure bake (PEB) is performed after the exposing operation but prior to the developing operation.

In both the PB operation and the PEB operation, the baking is preferably performed at 70 to 130°C, more preferably 80 to 120°C.

The baking time is preferably in the range of 30 to 300 seconds, more preferably 30 to 180 seconds and further more preferably 30 to 90 seconds.

The baking can be performed by means provided in the common exposure/development equipment. The baking can also be performed using a hot plate or the like.

The baking accelerates the reaction in exposed areas, so that the sensitivity and pattern profile can be enhanced.

The wavelength of light source for use in the exposure apparatus in the present invention is not particularly limited. Use can be made of infrared rays, visible light, ultraviolet rays, far ultraviolet rays, extrerne jultrayiolet 1ight_,_JrJta .s_,___electxon- beams, etc. Preferred use is made of far ultraviolet rays of wavelength preferably 250 nm or shorter, more preferably 220 nm or shorter and most preferably 1 to 200 nm, such as a KrF excimer laser (248 nm) , an ArF excimer laser (193 nm) and an F2 excimer laser

(157 nm) , X-rays, EUV (13 nm) , electron beams, etc. A KrF excimer laser, an ArF excimer laser, EUV and electron beams are more preferred. An ArF excimer laser is most preferred.

A technique of liquid immersion exposure can be employed in the exposing operation according to the present invention.

The technique of liquid immersion exposure is a technology for realizing an enhancement of resolving power, which comprises exposing while filling the space between a projector lens and a sample with a liquid of high refractive index (hereinafter also referred to as "immersion liquid") .

The "effect of the liquid immersion" is as

follows. Taking XQ as the wavelength of exposure light in air, n as the refractive index of the immersion liquid to air and Θ as the convergent half angle of the light beam, and providing that NAQ = sin9, the

resolving power and focus latitude (DOF) in the event of liquid immersion can be expressed by the following formulae. In the formulae, k]_ and k ₂ are coefficients relating to process.

(Resolving power) = k]_ · (Ag/n) /NAQ

(DOF) = ±k ₂ - (λ ₀ / ^η ) /NA ₀ ²

That is, the effect of the liquid immersion is equivalent to the use of an exposure wavelength of 1/n. In other words, in projection optic systems of

identical NA , the liquid immersion enables the focal depth to be n-fold. This is effective in all pattern -shapes Further-, this -can be combined wi a super-resolution technology, such as a phase shift method or a modified illumination method, now under study.

When the liquid immersion exposure is performed, the operation of washing the film surface with an aqueous chemical liquid may be carried out (1) after the film formation on the substrate but prior to the operation of exposure, and/or (2) after the operation of exposing the film to light via the immersion liquid but before the operation of baking the film.

The immersion liquid is preferably comprised of a liquid being transparent in exposure wavelength, whose temperature coefficient of refractive index is as low as possible so as to ensure minimization of any

distortion of optical image projected on the film.

Especially in the use of an ArF excimer laser

(wavelength: 193 nm) as an exposure light source, it is preferred to use water from not only the above

and easy handling.

In the use of water as the immersion liquid, an additive (liquid) capable of not only decreasing the surface tension of water but also increasing an

interface activating power may be added in a slight proportion. It is preferred for this additive to be one that does not dissolve the resist layer on the wafer and is negligible with respect to its influence on the optical coat applied to an under surface of lens element .

The additive is preferably, for example, an aliphatic alcohol exhibiting a refractive index

approximately equal to that of water, such as methyl alcohol, ethyl alcohol, isopropyl alcohol or the like. The addition of an alcohol exhibiting a refractive index approximately equal to that of water is

advantageous in that even when the alcohol component is evaporated from water to thereby cause a _chan_ge__of_ _. content concentration, any change of refractive index of the liquid as a whole can be minimized.

On the other hand, when a substance being opaque in 193 nm light or an impurity whose refractive index is greatly different from that of water is mingled in the immersion water, a distortion of optical image projected on the resist is invited. Accordingly, it is preferred to use distilled water as the immersion water. Furthermore, use may be made of pure water having been filtered through an ion exchange filter or the like.

Desirably, the electrical resistance of the water used as the immersion liquid is 18.3 MQcm or higher, and the TOC (organic matter concentration) thereof is 20 ppb or below. Prior deaeration of the water is desired.

The lithography performance can be enhanced by raising the refractive index of the immersion liquid. From this viewpoint, an additive suitable for

refractive index increase may be added to the water, or heavy water (D2O) may be used in place of the water.

The receding contact angle of the resist film formed from the actinic-ray- or radiation-sensitive resin composition of the present invention is 70° or greater at 23±3°C in 45±5% humidity, which is

appropriate in the exposure via the liquid immersion medium. The receding contact angle is preferably 75° or greater, more preferably 75 to 85°.

When the receding contact angle is extremely small, the resist film cannot be appropriate in the exposure via the liquid immersion medium, and the effect of suppressing any residual water (watermark) defect cannot be satisfactorily exerted.

When the above-mentioned hydrophobic resin (HR) contains substantially none of fluorine and silicon atoms , _t.he_ ^e_ceding_contacLang1e„o_£__th.e_s_u fa.c.e_-of—the- resist film can be increased by incorporating the hydrophobic resin (HR) in the actinic-ray- or

radiation-sensitive resin composition of the present invention.

From the viewpoint of increasing the receding contact angle, it is preferred for the hydrophobic resin (HR) to comprise at least either repeating unit of general formula (II) above or repeating unit of general formula (III) above. Further, from the

viewpoint of increasing the receding contact angle, it is preferred for the ClogP value of the hydrophobic resin (HR) to be 1.5 or greater. Still further, from the viewpoint of increasing the receding contact angle, it is preferred for the mass content of CH3 partial structure introduced in a side chain portion of the hydrophobic resin (HR) in the hydrophobic resin (HR) to be 12.0% or more .

In the operation of liquid immersion exposure, it is needed for the immersion liquid to move on the wafer while tracking the movement of an exposure head

involving high-speed scanning on the wafer and thus forming an exposure pattern. Therefore, the contact angle of the immersion liquid with respect to the resist film in a dynamic condition is important, and it is required for the resist to be capable of tracking the high-speed scanning of the exposure head without leaving any droplets.

The substrate used for film formation in the present invention is not particularly limited. Use can be made of any of an inorganic substrate of silicon, SiN, SiC>2, TiN or the like, a coated inorganic

substrate such as SOG and substrates commonly employed in a semiconductor production process for an IC or the like, a circuit board production process for a liquid crystal, a thermal head or the like and other photoapplication lithography processes. Further, ^■■ according to necessity, an organic antireflection film may be provided between the resist film and the substrate .

When the pattern forming method of the present invention further comprises the operation of developing with an alkali developer, as the alkali developer, use can be made of, for example, any of alkaline aqueous solutions containing an inorganic alkali such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate or aqueous

ammonia, a primary amine such as ethylamine or n- propylamine, a secondary amine such as diethylamine or di-n-butylamine, a tertiary amine such as triethylamine or methyldiethylamine, an alcoholamine such as

dimethylethanolamine or triethanolamine, a quaternary ammonium salt such as tetramethylammonium hydroxide or tetraethylammonium hydroxide, a cycloamine such as pyrrole or piperidine, and the like.

Appropriate amounts of an alcohol and a surfactant may be added to the above alkaline aqueous solutions before the use thereof.

The alkali concentration of the alkali developer is generally in the range of 0.1 to 20 mass%.

The pH value of the alkali developer is generally in the range of 10.0 to 15.0.

A 2.38 mass% aqueous tetramethylammonium hydroxide solution is particularly preferred.

Pure water is used as the rinse liquid for use in the rinse treatment performed after the alkali

development. Before the use thereof, an appropriate amount of surfactant may be added thereto.

Further, the development operation or rinse operation may be followed by the operation of removing any portion of developer or rinse liquid adhering onto the pattern by use of a supercritical fluid.

As the developer (hereinafter also referred to as an organic developer) for use in the operation of developing with a developer comprising an organic solvent to be performed in the pattern forming method of the present invention, use can be made of a polar solvent, such as a ketone solvent, an ester solvent, an alcohol solvent, an amide solvent or an ether solvent, and a hydrocarbon solvent.

As the ketone solvent, there can be mentioned, for xample_,^_l-_pctanone,_2 _p_c_t,anone., 1-_nonanone-,— 2~

nonanone, acetone, 2-heptanone (methyl amyl ketone) , 4- heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, cyclohexanone, methylcyclohexanone, phenylacetone, methyl ethyl ketone, methyl isobutyl ketone,

acetylacetone, acetonylacetone, ionone, diacetonyl alcohol, acetyl carbinol, acetophenone, methyl naphthyl ketone, isophorone, propylene carbonate or the like.

As the ester solvent, there, can be mentioned, for example, methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, pentyl acetate, isopentyl acetate, amyl acetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl 3- ethoxypropionate, 3-methoxybutyl acetate, 3-methyl-3- methoxybutyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, propyl lactate or the like.

As the alcohol solvent, there can be mentioned, for example, an alcohol, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, n-hexyl alcohol, n-heptyl alcohol, n- octyl alcohol or n-decanol; a glycol solvent, such as ethylene glycol, diethylene glycol, or triethylene glycol; a glycol ether solvent, such as ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monoethyl ether, diethylene glycol monomethyl ether, triethylene glycol monoethyl ether or

methoxymethylbutanol ; or the like.

As the ether solvent, there can be mentioned, for example, not only any of the above-mentioned glycol ether solvents but also dioxane, tetrahydrofuran or the like . As the amide solvent, there can be mentioned, for example, N-methyl-2-pyrrolidone, N, -dimethylacetamide, N, N-dimethylformamide, hexamethylphosphoric triamide, 1 , 3-dimethyl-2-imidazolidinone or the like.

As the hydrocarbon solvent, there can be

mentioned, for example, an aromatic hydrocarbon

solvent, such as toluene or xylene, or an aliphatic hydrocarbon solvent, such as pentane, hexane, octane or decane.

Two or more of these solvents may be mixed

together before use. Alternatively, each of the solvents may be used in a mixture with a solvent other than those mentioned above or water. However, from the viewpoint of the fullest exertion of the effects of the present invention, it is preferred for the water content of the whole developer to be less than

10 mass%. More preferably, the developer contains substantially no water.

Namely, the amount of organic solvent used in the organic developer is preferably in the range of 90 to 100 mass%, more preferably 95 to 100 mass%, based on the whole amount of the developer.

It is especially preferred for the organic

developer to be a developer comprising at least one organic solvent selected from the group consisting of a ketone solvent, an ester solvent, an alcohol solvent, an amide solvent and an ether solvent. The vapor pressure of the organic developer at 20°C is preferably 5 kPa or below, more preferably 3 kPa or below and most preferably 2 kPa or below.

When the vapor pressure of the organic developer is 5 kPa or below, the evaporation of the developer on a substrate or in a development cup can be suppressed, so that the temperature uniformity within the plane of the wafer can be enhanced to thereby improve the

dimensional uniformity within the plane of the wafer.

As particular examples of jthe ^rg .nic_ jieye^opejrs exhibiting a vapor pressure of 5 kPa or below, there can be mentioned a ketone solvent, such as 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, 2-heptanone (methyl amyl ketone) , 4-heptanone, 2-hexanone, diisobutyl ketone, cyclohexanone, methylcyclohexanone,

phenylacetone or methyl isobutyl ketone; an ester solvent, such as butyl acetate, pentyl acetate,

isopentyl acetate, amyl acetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl 3-ethoxypropionate, 3-methoxybutyl acetate, 3- methyl-3-methoxybutyl acetate, butyl formate, propyl formate, ethyl lactate, butyl lactate or propyl

lactate; an alcohol solvent, such as n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, n-hexyl alcohol, n-heptyl alcohol, n-octyl alcohol or n-decanol; a glycol solvent, such as ethylene glycol, diethylene glycol or triethylene glycol; a glycol ether solvent, such as ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monoethyl ether, diethylene glycol monomethyl ether, triethylene glycol monoethyl ether or methoxymethylbutanol ; an ether solvent, such as tetrahydrofuran; an amide solvent, such as N-methyl- 2-pyrrolidone, N, N-dimethylacetamide or N,N- dimethylformamide; an aromatic hydrocarbon solvent, such as toluene or xylene, and an aliphatic hydrocarbon solvent, such as octane or decane.

As particular examples of the organic developers exhibiting a vapor pressure of 2 kPa or below as an especially preferred range, there can be mentioned a ketone solvent, such as 1-octanone, 2-octanone, 1- nonanone, 2-nonanone, 4-heptanone, 2-hexanone,

diisobutyl ketone, cyclohexanone, methylcyclohexanone or phenylacetone ; an ester solvent, such as butyl acetate, amyl acetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl 3- ethoxypropionate, 3-methoxybutyl acetate, 3-methyl-3- methoxybutyl acetate, ethyl lactate, butyl lactate or propyl lactate; an alcohol solvent, such as n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, n-hexyl alcohol, n-heptyl alcohol, n- octyl alcohol or n-decanol; a glycol solvent, such as ethylene glycol, diethylene glycol or triethylene glycol; a glycol ether solvent, such as ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monoethyl ether, diethylene glycol monomethyl ether, triethylene glycol monoethyl ether or

methoxymethylbutanol ; an amide solvent, such as N- methyl-2-pyrrolidone, N, -dimethylacetamide or N,N- dimethylformamide ; an aromatic hydrocarbon solvent, such as xylene; and an aliphatic hydrocarbon solvent, such as octane or decane.

According to necessity, an appropriate amount of surfactant can be added to the organic developer.

The surfactant is not particularly limited. For example, use can be made of any of ionic and nonionic fiuor Lr.ated and/or siliconized surfactants and the like. As such fluorinated and/or siliconized

surfactants, there can be mentioned, for example, those described in JP-A' s S62-36663, S61-226746, S61-226745, S62-170950, S63-34540, H7-230165, H8-62834, H9-54432 and H9-5988 and USPs 5405720, 5360692, 5529881,

5296330, 5436098, 5576143, 5294511 and 5824451.

Nonionic surfactants are preferred. Although nonionic surfactants are not particularly limited, using a fluorinated surfactant or siliconized surfactant is more preferred.

The amount of surfactant added is generally in the range of 0.001 to 5 mass%, preferably 0.005 to 2 mass% and more preferably 0.01 to 0.5 mass% based on the whole amount of the developer.

As the development method, use can be made of, for example, a- method in which the substrate is dipped in a tank filled with a developer for a given period of time (dip method) , a method in which a developer is puddled on the surface of the substrate by its surface tension and allowed to stand still for a given period of time to thereby effect development (puddle method) , a method in which a developer is sprayed onto the surface of the substrate (spray method) , or a method in which a developer is continuously discharged onto the substrate being rotated at a given speed while scanning a

developer discharge nozzle at a given speed (dynamic dispense method) .

With respect to the above various development methods, when the operation of discharging a developer toward a resist film through a development nozzle of a development apparatus is included, the discharge pressure of discharged developer (flow rate per area of discharged developer) is preferably 2 ml/sec/mm^ or below, more preferably 1.5 ml/sec/mm^ or below and further more preferably 1 ml/sec/mm^ or below. There is no particular lower limit of the flow rate.

However, from the viewpoint of through-put, it is preferred for the flow rate to be 0.2 ml/sec/mm2 or highe .

Pattern defects attributed to any resist residue after development can be markedly reduced by regulating the discharge pressure of discharged developer so as to fall within the above range.

The detail of the mechanism thereof has not been elucidated. However, it is presumed that regulating the discharge pressure .so as to fall within the above range decreases the pressure of the developer on the resist film, thereby inhibiting any inadvertent shaving or crumbling of the resist film/resist pattern.

The discharge pressure of developer (ml/sec/mm^) refers to a value exhibited at the outlet of the development nozzle of the development apparatus.

For the regulation of the discharge pressure of developer, there can be employed, for example, a method in which the discharge pressure is regulated by means of a pump or the like, or a method in which the

discharge pressure is changed through pressure

regulation by supply from a pressure tank.

The operation of developing with a developer comprising an organic solvent may be followed by the operation of discontinuing the development by

replacement with another solvent. . The operation of developing with a developer comprising an organic solvent is preferably followed by the operation of rinsing the developed film with a rinse liquid.

The rinse liquid for use in the rinse operation after the operation of development with a developer comprising an organic solvent is not particularly limited as long as it does not dissolve the resist pattern, and solutions comprising common organic solvents can be used as the same. It is preferred for the rinse liquid to be one comprising at least one organic solvent selected from the group consisting of a hydrocarbon solvent, a ketone solvent, an ester

solvent, an alcohol solvent, an amide solvent and an ether solvent.

Particular examples of the hydrocarbon solvent, ketone solvent, ester solvent, alcohol solvent, amide solvent and ether solvent are the same as set forth aboy_e_in._c.Qnn_e.c_t.Ian.__w.i_t.h_th.e__de_veloper__compr _isin.g_an— organic solvent.

The operation of developing with the developer comprising an organic solvent is preferably followed by the operation of rinsing with a rinse liquid comprising at least one organic solvent selected from the group consisting of a ketone solvent, an ester solvent, an alcohol solvent and an amide solvent; more preferably followed by the operation of rinsing with a rinse liquid comprising an alcohol solvent or an ester solvent; further more preferably followed by the operation of rinsing with a rinse liquid comprising a monohydric alcohol; and most preferably followed by the operation of rinsing with a rinse liquid comprising a monohydric alcohol having 5 or more carbon atoms.

As the monohydric alcohol for use in the . rinse operation, there can be mentioned a linear, branched or cyclic monohydric alcohol. In particular, use can be made of 1-butanol, 2-butanol, 3-methyl-l-butanol , tert- butyl alcohol, 1-pentanol, 2-pentanol, 1-hexanol, 4- methyl-2-pentanol , 1-heptanol, 1-octanol, 2-hexanol, cyclopentanol , 2-heptanol, 2-octanol, 3-hexanol, 3- heptanol, 3-octanol, 4-octanol or the like. As the most preferred monohydric alcohol having 5 or more carbon atoms, use can be made of 1-hexanol, 2-hexanol, 4-methyl-2-pentanol , 1-pentanol, 3-methyl-l-butanol or the like.

_Twp_ or more of these_co.mp.anent.S—ma —he—m ed— together before use. Also, they may be mixed with other organic solvents before use.

The water content of the rinse liquid is

preferably 10 mass% or below, more preferably 5 mass% or below and most preferably 3 raassl or below.

Favorable development performance can be attained by controlling the water content of the rinse liquid at 10 mass% or below. With respect to the rinse liquid for use after the operation of developing with a developer comprising an organic solvent, the vapor pressure thereof at 20°C is preferably in the range of 0.05 to 5 kPa, more

preferably 0.1 to 5 kPa and most preferably 0.12 to 3 kPa. When the vapor pressure of the rinse liquid is in the range of 0.05 to 5 kPa, not only can the

temperature uniformity within the plane of the wafer be enhanced but also the swell attributed to the

penetration of the rinse liquid can be suppressed to thereby improve the dimensional uniformity within the - plane of the wafer.

An appropriate amount of surfactant may be added to the rinse liquid before use.

In the rinse operation, the wafer having undergone the development with a developer comprising an organic solvent is rinsed with the above rinse liquid

comprising an organic solvent. The method of rinse treatment is not p>art_ic:u1arl_y__1imit_ecL. For example, use can be made of any of a method in which the rinse liquid is continuously applied onto the substrate being rotated at a given speed (spin application method) , a method in which the substrate is dipped in a tank filled with the rinse liquid for a given period of time (dip method) and a method in which the rinse liquid is sprayed onto the surface of the substrate (spray method). Preferably, the rinse treatment is carried out according to the spin application method, and thereafter the substrate is rotated at a rotating speed of 2000 to 4000 rpm to thereby remove the rinse liquid from the top of the substrate. Also, preferably, a baking operation (post-bake) is carried out subsequent to the rinse operation. Any inter-pattern and intra- pattern remaining developer and rinse liquid are removed by carrying out the bake. The bake operation subsequent to the rinse operation is generally

performed at 40 to 160°C, preferably 70 to 95°C, for a period of 10 seconds to 3 minutes, preferably 30 to 90 seconds.

Furthermore, the present invention relates to a process for manufacturing an electronic device in which the above-described negative pattern forming method of the present invention is included, and relates to an electronic device manufactured by the process.

The electronic device of the present invention can be appropriately mounted in electrical and electronic equipments (household electronic appliance, OA/media- related equipment, optical apparatus, telecommunication equipment and the like) .

EXAMPLES

The present invention will be described in greater detail below by way of its examples. However, the gist of the present invention is in no way limited to these examples . <Resin (A) >

(Synthetic Example 1: synthesis of resin Pol-01) In a nitrogen gas stream, 111.4 g of cyclohexanone was placed in a three-necked flask and heated at 80°C. A solution obtained by dissolving the compounds

(monomers) indicated in Table 2 below (amounting in order from the left side to 18.7 g, 20.4 g, 14.7 g and 2.4 g) and further polymerization initiator V601

(produced by Wako Pure Chemical Industries, Ltd.,

3.20 g) in 206.9 g of cyclohexanone was dropped

thereinto over a period of 6 hours. After the

completion of the dropping, reaction was continued at 80°C for 2 hours. The thus obtained reaction liquid was allowed to stand still to cool, and was dropped into a mixed liquid comprised of 1600 g of n-heptane and 400 g of ethyl acetate over a period of 20 minutes. The thus precipitated powder was collected by

filtration and dried, thereby obtaining 47.2 g of resin Pol-01. The polymer component ratio thereof determined by NMR was 30/40/25/5. With respect to the obtained ^' resin · Pol-01 , the standard-polystyrene-equivalent weight average molecular weight (Mw) determined by GPC analysis was 11,200, and the polydispersity index

(Mw/ n) was 1.68.

Resins Pol-02 to Pol-21 were synthesized in the same manner as in Synthetic Example 1. Table 2 below lists the structures of synthesized polymers together with the component ratios, weight average molecular weights (Mw) and polydispersity indices (Mw/Mn) thereof. In Table 2, .the positional relationship of individual repeating units of each of the resins corresponds to the positional relationship of component ratio numeric values.

<Acid generator; PAG>

The following compounds PAG-1 to PAG-14 were usedid generators.

PAG-14

PAG-13 <Basic compound>

The following compounds were used as basic compounds .

N-9

<Surfactant>

The following surfactants were used.

W-l: Megafac F176 (produced by DIC Corporation, fluorinated) , W-2: Megafac R08 (produced by DIC Corporation, fluorinated and siliconized) ,

W-3: polysiloxane polymer KP-341 (produced by Shin-Etsu Chemical Co., Ltd., siliconized),

W-4: Troy Sol S-366 (produced by Troy Chemical Co . , Ltd . ) ,

W-5: _. KH-20 (produced by Asahi Kasei Corporation), and

W-6: PolyFox™ PF-6320 (produced by OMNOVA

SOLUTIONS, INC., fluorinated).

<Additive>

The following additives were used.

(3b) (4b) <Solvent>

The following solvents were used.

SL-1: propylene glycol monomethyl ether acetate (PGMEA),

SL-2 : ethyl lactate, SL-3: propylene glycol monomethyl ether (PGME),

SL-4: cyclohexanone, and

SL-5: γ-butyrolactone .

[Evaluation method]

<ArF liquid-immersion exposure>

(Preparation of resist and formation of pattern) Actinic-ray- or radiation-sensitive resin

compositions (resist compositions) were prepared by dissolving individual components indicated in Table 4 below in solvents indicated in the table at a solid content of 3.4 mass% and passing the solutions through a polyethylene filter of 0.03 μπι pore size.

Separately, an organic antireflection film ARC29SR (produced by Nissan Chemical Industries, Ltd.) was applied onto a silicon wafer and baked at 205°C for 60 seconds, thereby forming a 95 nm-thick

antireflection film. Each of the prepared resist compositions was applied thereonto and prebaked (PB), thereby forming a 90 nn-Lhick. resist film.

Each of the resultant wafers was patternwise exposed through a binary mask to light by means of an ArF liquid-immersion exposure apparatus (NA 1.20). The exposed wafer was subjected to post-exposure bake

(PEB), developed with a negative developer for

30 seconds, and optionally rinsed with a rinse liquid. Thereafter, the wafer was rotated at a rotating speed of 4000 rpm for 30 seconds. Thus, a 44 nm (1:1) line-and-space resist pattern was obtained.

Table 3 below lists the PE and PEB conditions (temperature (°C) and time (second)) together with developer and rinse liquid employed for pattern formation in each of Examples and Comparative Example

Table 3

( Continued)

Table 3

(Exposure latitude; EL)

The optimum exposure amount was defined as the exposure amount that formed the obtained 44 nm (1:1) line-and-space resist pattern. The exposure amount width allowing + 10% of the pattern size when the exposure amount was varied was measured. The exposure latitude is the quotient of the value of the exposure amount width divided by the optimum exposure amount, the quotient expressed by a percentage. The greater the value of the exposure latitude, the less the change of performance by exposure amount changes and the better the EL.

(Focus latitude; depth of focus DOF)

The optimum exposure amount and optimum focus were defined as the exposure amount and focus that formed the obtained 44 nm (1:1) line-and-space resist pattern, respectively. The focus was varied while fixing the exposure amount at the optimum exposure amount, and the focus width allowing ± 10% of the pattern size or the focus width up to the occurrence of a pattern bridge was measured. The greater the value of the focus width, the less the change of performance by focus changes and the better the DOF.

(Line width roughness; LWR)

Each of the obtained 44 nm (1:1) line-and-space resist patterns was observed by means of a critical dimension scanning electron microscope (SEM model S-9380II, manufactured by Hitachi, Ltd.). The line width was measured at 50 points of equal intervals within 2 μπι in the longitudinal direction of the space pattern. The standard deviation of measured line widths was determined, and 3σ was computed therefrom. The smaller the value thereof, the higher the

performance exhibited.

(Pattern collapse)

In the formation of the 44 nm (1:1) line-and-space resist pattern, the space line width immediately prior to the occurrence of pattern collapse upon changes of the exposure amount was digitized and used as an index for the evaluation of pattern collapse. The larger the value thereof, the larger the resultant space (finer line) and the better the performance exhibited.

Table 4

(Continued)

Table 4

(Continued)

Table 4

(Continued)

Table 4

It is apparent from the above obtained results that the method of forming a negative pattern according to the present invention excels in the exposure

latitude, line width roughness and focus latitude. It is also apparent that the method can give satisfactory results with respect to the pattern collapse.