Field of the Invention

The present invention relates to a photoresist stripper composition, comprising a polar organic solvent, a basic primary or secondary alkanolamine compound or a combination thereof, a tertiary ammonium compound, and an inhibitor for preventing metal etching.

Description of the Prior Art

The etching process is considered one of the most important steps in the lithographic process in semiconductor and thin-film transistor liquid crystal display (TFT-LCD) industries. Generally, a device pattern on a photo mask is transferred onto a photoresist through a lithographic process, and then the pattern is transferred onto a thin film through an etching process. After the lithographic and etching processes, the thin film will function as a part of the semiconductor device. In the manufacturing process of a metal oxide semiconductor device or a complementary metal oxide semiconductor device, for example, such a film may be Siθ2, SisN4, Poly- Si, Al alloy, copper, phosphosilicate (PSG), and so on. In other words, almost all the main materials of a semiconductor device must undergo a process of thin film deposition, lithography, and etching, so that the device is manufactured layer by layer.

For example, in a common process for forming a conductor pattern, first, a silicon oxide layer and a conductor layer (polycrystalline silicon or other metal materials such as aluminum or copper) are generally formed on a substrate in sequence; next, a patterned photoresist layer is formed on the conductor layer; then, with the photoresist layer as an etching mask, the exposed conductor layer is dry- etched to form a conductor pattern; afterwards, the photoresist layer is removed.

However, during the above process for forming the conductor pattern, as the gas for etching the conductor layer contains carbon, chlorine or oxygen, it may chemically react with the photoresist layer and the conductor layer, thereby forming a high molecular residue on the sidewalls of the photoresist layer and the conductor layer. In addition to affecting the subsequent process, the high molecular residue may also degrade the performance of conductor layers. Accordingly, after removing the patterned photoresist layer, a cleaning process is generally performed to remove the high molecular residue attached to the surface of the conductor pattern after dry etching.

For example, during a manufacturing process of a TFT-LCD array, a substrate is first provided, said substrate at least having a copper line conductor layer and a dielectric layer located on the copper line conductor layer; then, an etching pattern desired is defined with a photo mask to perform etching, so as to form an opening for exposing a part of the conductive copper lines.

Relevant disclosure of photoresist stripper compositions has been provided in prior art. For example, JP 2005-043874 discloses a liquid photoresist stripper composition, which contains 5 wt% to 50 wt% of an organic amine compound, 10 wt% to 50 wt% of an ethylene glycol ether compound, 0 wt% to 30 wt% of a water soluble organic solvent, 0.1 wt% to 10 wt% of a preserver, and deionized water.

WO 2007/139315 also relates to a photoresist stripper composition, which comprises a corrosion inhibitor, a water soluble organic amine compound with a content that is 2 to 50 times the weight of the corrosion inhibitor, and a polar solvent. This composition can easily strip the hardened photoresist produced in the wet or dry etching procedure without destroying the metal film and oxide film materials exposed under the composition, and the subsequent cleaning step can be carried out with water alone.

WO 2007/037628 provides a photoresist stripper composition, which contains 5 wt% to 30 wt% of an organic amine compound, 10 wt% to 30 wt% of an ethylene glycol ether compound, 10 wt% to 50 wt% of a water soluble organic solvent, 0.1 wt% to 10 wt% of a corrosion inhibitor, 0.1 wt% to 5 wt% of an oxide as co-solvent, and deionized water. Such a composition can remove both the photoresist and the oxides released from the substrate when the photoresist is being removed, such as ITO (indium tin oxide) and IZO (indium zinc oxide).

TW546553 discloses a liquid photoresist stripper composition, which contains alkanolamines, carbohydrates, a water soluble organic vehicle, benzotriazole or a derivative thereof, and water. TW228640 discloses a photoresist stripper composition, which contains a water soluble organic solvent, water, an alkylamine or an alkanolamine, acetic acid, an oxime compound, an organic phenol compound, and a triazole compound.

The inventors of the present invention found that the photoresist stripper composition of the present invention can effectively strip organic photoresist without etching metal substrates, and can also remove the oxides from the metal surfaces.

Summary of the Invention

The present invention is directed to a photoresist stripper composition, comprising: (1 ) a polar organic solvent;

(2) a basic primary or secondary alkanolamine compound or a combination thereof;

(3) a tertiary amine compound; and

(4) an inhibitor for preventing metal etching.

The present invention is further directed to a photoresist stripper composition, comprising:

(1 ) a polar organic solvent;

(2) a basic primary or secondary alkanolamine compound or a combination thereof;

(3) a tertiary amine compound;

(4) an inhibitor for preventing metal etching; and

(5) an organic acid.

The composition of the present invention can easily and quickly remove photoresist films transferred and hardened on a substrate during the process of dry etching, polishing, or ion implantation, and the transferred photoresist film of the metal by-product etched from the metal film at the bottom during the above processes. Furthermore, the composition can also reduce the corrosion of the bottom metal lines, especially copper lines, during the removal of the photoresist, and remove the oxides from the metal surfaces.

The present invention is further directed to a use of the photoresist stripper composition of the present invention in stripping the photoresist films transferred and hardened during the process of dry etching, polishing, or ion implantation.

The present invention is further directed to a process for stripping a photoresist film on a substrate using the photoresist stripper composition of the present invention.

The present invention is further directed to a process for manufacturing a semiconductor device using the photoresist stripper composition of the present invention.

Brief Description of the Drawings

Fig. 1 shows a substrate having organic photoresist on a surface thereof;

Fig. 2 shows the test results of Comparative Example 1 in which the organic photoresist on the substrate is not completely stripped;

Fig. 3 shows the test results of Comparative Example 2 in which the organic photoresist on the substrate is stripped at the cost of partial etching of the metal;

Fig. 4 shows the test results of Example 2 of the present invention in which the organic photoresist on the substrate is completely stripped while the metal substrate is not etched; and

Fig. 5 shows the test results of Example 4 of the present invention in which the composition comprising an organic acid further removes the oxides from the metal.

Detailed Description

The present invention provides a photoresist stripper composition, comprising:

(1 ) a polar organic solvent;

(2) a basic primary and secondary alkanolamine compound or a combination thereof;

(3) a tertiary amine compound; and

(4) an inhibitor for preventing metal etching.

The photoresist stripper composition of the present invention can further comprise an organic acid.

In order to make the features and advantages of the present invention more comprehensible, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

The polar organic solvent useful as component (1 ) in the photoresist stripper composition of the present invention is selected from one or more of the following components or a combination thereof:

(1 ) a glycol ether or a derivative thereof;

(2) amides represented by the following formula:

wherein R ^w is H or Ci _-4 alkyl; R ^x and R ^y are independently the same or different Ci-6 alkyl, preferably Ci _-4 alkyl;

(3) N-methyl-pyrrolidone (NMP); and

(4) suiphoxides represented by the following formula:

O

_R m _R n

R ⁿ and R ^m are independently the same or different H, OH or Ci _-4 alkyl, wherein at least one of R ⁿ and R ^m is Ci _-4 alkyl; preferably Ci _-4 alkyl; The preferred glycol ether or a derivative thereof include diethylene glycol monobutyl ether (BDG), diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol monobutyl ether acetate, or a mixture thereof.

The preferred amides include N,N-dimethyl acetamide (DMAC), N,N-dimethyl formamide (DMF), N.N-diethylformamide, N,N-diethyl acetoacetamide, N ₁ N-

The suiphoxides include dimethyl sulfoxide (DMSO).

In the composition of the present invention, the content of the solvent can be adjusted by persons of skill in the art as desired, and generally is about 60 wt% to about 84 wt%, preferably about 65 wt% to about 80 wt%, and more preferably about 65 wt% to about 75 wt%, based on the total weight of the whole composition.

Component (2) in the photoresist stripper composition of the present invention is a basic primary or secondary alkanolamine compound. One or more of basic primary alkanolamine compounds or one or more of basic secondary alkanolamine compounds can be used, or one or more of basic primary alkanolamine compounds and one or more of basic secondary alkanolamine compounds can be jointly used. The primary alkanolamine compound is represented by the following formula:

R- N H ₂ wherein R is linear or branched Ci-io hydroxyalkyl (preferably C1-6 hydroxyalkyl), linear or branched C2-10 hydroxyalkenyl (preferably C2-6 hydroxyalkenyl) or C3-8 hydroxycycloalkyl.

The secondary alkanolamine compound is represented by the following formula: wherein R ¹ and R ² are independently the same or different linear or branched C1-10 alkyl or hydroxyalkyl (preferably C-i-β), linear or branched C2-10 alkenyl or hydroxyalkenyl (preferably C2-6) or C3-8 cycloalkyl or hydroxycycloalkyl, and at least one of R ¹ and R ² is hydroxyalkyl, hydroxyalkenyl or hydroxycycloalkyl.

The preferred primary or secondary alkanolamine compound includes monoethanolamine (MEA), N-methyl ethanolamine, N-ethyl ethanolamine, or a mixture thereof.

In the composition of the present invention, the content of the primary or secondary alkanolamine compound or a mixture thereof can be adjusted by persons of skill in the art as desired, and generally is about 2 wt% to about 10 wt%, preferably about 2 wt% to about 8 wt%, and more preferably about 2 wt% to about 5 wt%, based on the total weight of the whole composition.

Component (3) of the photoresist stripper composition of the present invention is a tertiary amine compound represented by the following formula: wherein R ³ , R ⁴ , and R ⁵ are independently the same or different linear or branched Ci-io alkyl or hydroxyalkyl (preferably C2-6), linear or branched C2-10 alkenyl or hydroxyalkenyl (preferably C2-6) or C3-8 cycloalkyl or hydroxycycloalkyl.

The preferred tertiary amine compounds are triethylamine (TEA), diethylamino ethanol, 2-dimethylamino ethanol, N,N-dimethyl ethanolamine, N-methyl,N-ethyl ethanolamine or a mixture thereof.

In the composition of the present invention, the content of the tertiary amine compound can be adjusted by persons of skill in the art as desired, and generally is about 13 wt% to about 35 wt%, and preferably about 23 wt% to about 35 wt%, based on the total weight of the whole composition.

Component (4) of the present invention is an inhibitor for preventing metal etching, which is a component commonly used in the art, e.g., thiol derivatives, organic phenol compounds or azole compounds. These compounds can be used independently or in combination. The inhibitor useful in the present invention preferably includes thiol derivatives and organic phenol compounds.

For example, the thiol derivatives above can be, but are not limited to, thioglycerol, thiophene, thiourea, thioglycol, propyl mercaptan, 4-methyl-4H-1 ,2,4- triazole-3-thiol, 5-amino-1 ,3,4-thiadiazol-2-thiol or a mixture thereof.

The organic phenol compounds can be, but are not limited to, catechol, 4- methylcatechol, 4-nitrocatechol, chloroacetylcatechol, or a mixture thereof.

The azole compounds can be, but are not limited to, benzotriazole (BTA), imidazole, pyrazole, 5-aminotetrazole (ATA), 1 ,2,3-triazole, 1 ,2,4-triazole, benzimidazoie, methyl tetrazcfe, 1-hydroxybenzotπazcte, 3-armno-1 H-1 2,4-tπazoie, 3,5-dsam!no-1.2,4-tπazo!e toiyitriazole, 5-phenyl-benzotπazoie 5-nitro-benzotπazoie 3-armno-5-mercapto-1 ,2,4-tπazoie, 1-armno-i .2,4-tπazoie 2-{5-amιnopentyi}- benzotπazoie. i-ammo-1 ,2 3-tπazoie, 1-armno-5-rnethy!-1 ,2 3-tπazoie, 3-mercapto- 1 ,2,4-triazole, 3-isopropyl-1 ,2,4-triazole, 5-phenylthiol-benzotπazoie, halo benzcMπazole. !imidazole or a mixture thereof. The preferred inhibitors for preventing metal etching include thioglycerol, thiophene, thiourea, thioglycol, catechol, 4-methylcatechol, 4-nitrocatechol, chloroacetylcatechol, and BTA.

In the composition of the present invention, the content of the inhibitor can be adjusted by persons of skill in the art as desired, and generally is about 0.1 wt% to about 3 wt%, and preferably about 0.2 wt% to about 1 wt%, based on the total weight of the whole composition.

The composition of the present invention can optionally further comprise an organic acid of component (5) as follows:

where R ^a , R ^b and R ^c are independently H, Ci _-6 alkyl, hydroxyl, or R ^d -COOH; and

R ^d is Ci-6 alkylene.

The organic acid useful in the present invention includes, but is not limited to, acetic acid, α-hydroxyl acid, oxalic acid, or a mixture thereof. The α-hydroxyl acid above can be α-hydroxyl acids commonly used in the art, including, but not limited to, glycolic acid, lactic acid, malic acid, citric acid, or a mixture thereof.

In the composition of the present invention, the content of the organic acid can be adjusted by persons of skill in the art as desired, and generally is about 0.05 wt% to about 1 wt%, preferably about 0.1 wt% to about 0.7 wt%, and more preferably 0.15 wt% to about 0.5 wt%, based on the total weight of the whole composition.

The photoresist stripper composition of the present invention can be used to strip, for example, the photoresist films transferred and hardened during the process of dry etching, polishing, or ion implantation of the semiconductor substrate. The processing steps and operating conditions for stripping the photoresist films with the photoresist stripper composition of the present invention can be those of the conventional processes known in the art.

One embodiment of the process of using the photoresist stripper composition of the present invention comprises a step of contacting the photoresist stripper composition of the present invention with a substrate covered with a photoresist film.

The photoresist stripper composition of the present invention can be specifically applied to a semiconductor substrate. In particular, the present invention also provides a process for manufacturing a semiconductor device comprising the following steps:

(1 ) coating a photoresist film on the surface of a semiconductor substrate;

(2) forming a photoresist pattern on the substrate coated with the photoresist film;

(3) depositing an electrically conductive metal film or insulating film on the patterned substrate;

(4) removing the photoresist film by the photoresist stripper composition of the present invention; and

(5) cleaning the substrate with deionized water.

The present invention will be further described in detail with reference to the following embodiments. However, it is understood that the descriptions are only used to exemplify and illustrate the present invention and not intended to limit the scope of the present invention in any way, and the changes and modifications easily made by any person of skill in the art fall within the scope of the disclosure in the present specification and the appended claims.

Examples

Comparative Examples 1-2 and Examples 1-6

Comparative Examples 1-2 and Examples 1-6 are photoresist stripper compositions prepared by mixing the specific components according to the content (wt%) shown in Table 1.

Table 1

(2) Primary,

(3) Tertiary

Secondary (4) Inhibitor for Preventing (5) Organic

(1 ) Solvent Amine

Alkanolamine Metal Etching Acid

Example Compound

Compound

Acetic Glycolic

DMSO BDG MEA TTEEAA Thioglycerol Catechol BTA

Acid Acid

Comparative 69.5 30 0.5

Example 1

Comparative 60 10 30

Example 2

Example 1 20 48 5.5 26 0.5

Example 2 70 5 24.2 0.8 Example 3 64.2 2 33 0.5 0.3

Example 4 79 4.8 15 0.5 0.7

Example 5 76 3.5 20 0.3 0.2

Example 6 70 5 24.2 0.8

Test of stripping effect of organic photoresists

The test of stripping effect of organic photoresists includes the steps of:

(a) immersing a metal substrate containing organic photoresist in the respective photoresist stripper compositions of the Comparative Examples and Examples for about 1 to 20 min at a temperature of 30 to 65°C;

(b) washing the immersed metal substrate with deionized water; and

(c) observing the presence of photoresist residue and metal etching on the metal substrate with an optical microscope.

The test results are shown in Table 2. Table 2

Immersing temperature 30 to 65 ⁰ C

Test Results

1-10 min 10-20 min

Comparative Example 1 X X as shown in Fig. 2

Comparative Example 2 O O as shown in Fig. 3

Example 1 O O -

Example 2 O O as shown in Fig. 4

Example 3 O O -

Example 4 O O as shown in Fig. 5

Example 5 O O -

Example 6 O O

O: photoresist stripped; X: photoresist remaining

Test of metal etching

The test of metal etching includes the steps of:

(a) immersing the different metal substrates containing organic photoresist in the respective photoresist stripper compositions of the Comparative Examples and Examples for about 1 to 20 min at a temperature of 30 to 65°C;

(b) washing the immersed metal substrate with deionized water; and

(c) detecting the etching rate of various metal conductors on the metal substrates using a "four-point probe" method, in which a fixed current is applied to two of the four probes and the voltage difference between the other two probes is measured, so as to calculate the resistance of the sheet. Thus, the thickness of the chip is obtained through conventional equations.

The test results are shown in Table 3.

Table 3

Etching Rate Metal Substrate

(Angstrom/min) Aluminium Copper Titanium

Comparative Example 1 > 10000 > 10000 > 10000

Comparative Example 2 < 15 < 10 < 1

Example 1 < 15 < 10 < 1

Example 2 < 15 < 10 < 1

Example 3 < 15 < 10 < 1

Example 4 < 15 < 10 < 1

Example 5 < 15 < 10 < 1

Example 6 < 15 < 10 < 1

Figs. 1 to 4 are optical microscope photographs. Fig. 1 shows an untreated substrate with organic photoresist thereon. Fig. 2 shows a state after the organic photoresist on the substrate is removed, and the photograph shows that the organic photoresist is not completely removed (Comparative Example 1 ). Fig. 3 shows a state after the organic photoresist on the substrate is removed, and the photograph shows that the organic photoresist is removed at the cost of partial etching of the metal (Comparative Example 2). Fig. 4 shows a state after the organic photoresist on the substrate is removed, and the photograph shows that the organic photoresist is removed while the metal substrate is not etched, and the trace oxides on the metal are also removed (Example 2). Examples 1 and 6 obtained a result similar to that of Example 2. Fig. 5 compares the substrate before and after treatment with the composition comprising an organic acid according to the present invention, and the photograph shows that the composition can further remove the oxides from the metal part (Example 4). Examples 3 and 5 obtained a result similar to that of Example 4.

Compared with Comparative Examples 1 and 2, the compositions of Examples 1 , 2 and 6 of the present invention can not only effectively strip the photoresist, but also effectively reduce the etching of the metal substrate, thereby preventing the surface of the metal substrate from being damaged. Furthermore, the compositions of Examples 3 to 5 of the present invention can also remove the oxides from the metal.

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