DEPOSITION OF METAL-CONTAINING FILMS

Cross-Reference to Related Applications

This application claims the benefit under 35 U. S. C. § 119(e) to provisional application No. 61/224,752, filed July 10, 2009, the entire contents of which are incorporated herein by reference.

Background

The formation of metal-containing films via Chemical Vapor and Atomic Layer Deposition (CVD and ALD) are promising. Desirable properties of the metal-containing precursor for these applications are: i) high volatility, ii) sufficient stability to avoid decomposition during handling and delivery, and iii) appropriate reactivity.

PEALD and PECVD are promising techniques to produce high purity and high-density metal thin films at low growth temperatures.

E. Eisenbraun et al. J. Vac. Sci. Technol. B 25, 6, 2007 and

Eisenbraun, E. Electrochemical and Solid-State Letters, 11 , 5, H107-H110, 2008 describe the deposition of copper by PEALD using Cu(acac) ₂ and hydrogen as reductant. Continuous and pure films (95 % purity) were obtained on TaN, SiO ₂ and Ru in a temperature range between 85 and 135 ^° C. Moreover conformal depositions have been achieved over high aspect ratio (5:1 ) structures.

Summary

Disclosed are methods of forming a metal-containing film one or more substrates in a reactor. A metal-containing precursor having the formula shown below of Compound (I) or Compound (II) is introduced into the reactor:

Compound (I)

(I) wherein:

1 ) M is selected from the group consisting of Mn, Fe, Co, Ni, Ru, and Pd; and

2) each R ¹ , R ² , R ³ , and R ⁴ is independently selected from the group consisting of H, a CrC ₅ alkyl, an alkyl amino group, and Si(R') ₃ where each R' is independently, selected from H and a Ci-C ₅ alkyl group;

and

wherein

1 ) M is selected from the group consisting of Fe, Co, and Ru; and

2) each R ¹ , R ² , R ³ , and R ⁴ is independently selected from H, a CrC ₅ alkyl group, an alkyl amino group, and Si(R') ₃ where each R' is independently selected from H and a Ci-C ₅ alkyl group;

A co-reactant is introduced into the reactor. The precursor and the co- reactant react to form the metal-containing film on the substrate. The disclosed methods may include one or more of the following aspects:

• the M of compound (I) being selected from the group consisting of Pd, Ni, and Co;

• the co-reactant being selected from the group consisting of H ₂ , NH ₃ , SiH ₄ , Si ₂ H ₆ , Si ₃ H ₈ , SiH ₂ Me ₂ , SiH ₂ Et ₂ , N(SiH ₃ ) ₃ , and mixtures thereof;

• the co-reactant being selected from the group consisting of O ₂ , O ₃ , H ₂ O, NO, carboxylic acid, and mixtures thereof;

• treating the co-reactant with a plasma;

• introducing the metal-containing precursor and the co-reactant into the chamber substantially simultaneously;

• mixing the metal-containing precursor and the co-reactant together prior to introduction into the chamber;

• introducing the metal-containing precursor and the co-reactant into the chamber sequentially;

• the co-reactant being introduced prior to the metal-containing

precursor;

• the precursor being selected from the group consisting of:

bis(4N-(amino)pent-3-en-2-onato)Nickel(ll),

bis(4N-(methylamino)pent-3-en-2-onato) Nickel (II), bis(4N-(ethylamino)pent-3-en-2-onato) Nickel (II), bis(4N-(isopropylamino)pent-3-en-2-onato) Nickel (II), bis(4N-(n-propylamino)pent-3-en-2-onato) Nickel (II), bis(4N-(n-butylamino)pent-3-en-2-onato) Nickel (II), bis(4N-(isobutylamino)pent-3-en-2-onato) Nickel (II), bis(4N-(secbutylamino)pent-3-en-2-onato) Nickel (II), and bis(4N-(tertbutylamino)pent-3-en-2-onato) Nickel (II);

• the precursor being selected from the group consisting of:

bis(4N-(amino)pent-3-en-2-onato)Cobalt (II),

bis(4N-(methylamino)pent-3-en-2-onato) Cobalt (II), bis(4N-(ethylamino)pent-3-en-2-onato) Cobalt (II), bis(4N-(isopropylamino)pent-3-en-2-onato) Cobalt (II), bis(4N-(n-propylamino)pent-3-en-2-onato) Cobalt (II), bis(4N-(n-butylamino)pent-3-en-2-onato) Cobalt (II), bis(4N-(isobutylamino)pent-3-en-2-onato) Cobalt (II), bis(4N-(secbutylamino)pent-3-en-2-onato) Cobalt (II), and bis(4N-(tertbutylamino)pent-3-en-2-onato) Cobalt (II); and • the precursor being selected from the group consisting of:

bis(4N-(amino)pent-3-en-2-onato)Palladium (II), bis(4N-(methylamino)pent-3-en-2-onato) Palladium (II), bis(4N-(ethylamino)pent-3-en-2-onato) Palladium (II), bis(4N-(isopropylamino)pent-3-en-2-onato) Palladium (II), bis(4N-(n-propylamino)pent-3-en-2-onato) Palladium (II), bis(4N-(n-butylamino)pent-3-en-2-onato) Palladium (II), bis(4N-(isobutylamino)pent-3-en-2-onato) Palladium (II), bis(4N-(secbutylamino)pent-3-en-2-onato) Palladium (II), and bis(4N-(tertbutylamino)pent-3-en-2-onato) Palladium (II).

Also disclosed are metal-containing thin film coated substrates comprising the product of the disclosed methods.

Notation and Nomenclature

Certain terms are used throughout the following description and claims to refer to various components and constituents.

As used herein, the term "alkyl group" refers to saturated functional groups containing exclusively carbon and hydrogen atoms. Further, the term "alkyl group" may refer to linear, branched, or cyclic alkyl groups.

Examples of linear alkyl groups include without limitation, methyl groups, ethyl groups, propyl groups, butyl groups, etc. Examples of branched alkyls groups include without limitation, isopropyl groups, f-butyl groups, etc. Examples of cyclic alkyl groups include without limitation, cyclopropyl groups, cyclopentyl groups, cyclohexyl groups, etc. As used herein, the abbreviation "Me" refers to a methyl group; the abbreviation "Et" refers to an ethyl group; the abbreviation "iPr" refers to an isopropyl group; and the abbreviation "t-Bu" refers to a tertiary butyl group.

The standard abbreviations of the elements from the periodic table of elements are used herein. It should be understood that elements may be referred to by these abbreviations (e.g., Ni refers to nickel, Pd refers to palladium, Co refers to cobalt, etc).

As used herein, the term "independently" when used in the context of describing R groups should be understood to denote that the subject R group is not only independently selected relative to other R groups bearing the same or different subscripts or superscripts, but is also independently selected relative to any additional species of that same R group. For example in the formula MR ¹ _X (NR ² R ³ ) ₍₄ - _X) , where x is 2 or 3, the two or three R ¹ groups may, but need not be identical to each other or to R ² or to R ³ . Further, it should be understood that unless specifically stated otherwise, values of R groups are independent of each other when used in different formulas.

Description of Preferred Embodiments

Disclosed herein are non-limiting embodiments of methods, apparatus, and compounds which may be used in the manufacture of semiconductor, photovoltaic, LCD-TFT, or flat panel type devices. More specifically, disclosed are bis-ketoiminate metal precursors and methods for utilizing the same.

The disclosed metal-containing precursors may have the general formula:

Compound (I) wherein M is a transition metal with +2 oxidation state, selected from among the elements Mn, Fe, Co, Ni, Ru, and Pd. Preferably M is Ni, Co, or Pd. Each R ¹ , R ² , R ³ , and R ⁴ is independently selected from H, a C _r C ₅ alkyl group, an alkyl amino group, and Si(R') ₃ wherein each R' is

independently selected from H and a CrC ₅ alkyl group. Preferably R ¹ =Et, R ² and R ⁴ =Me, and R ³ =H.

Alternatively, the disclosed metal-containing precursors may have the general formula:

Compound (II)

wherein M is a transition metal with +3 oxidation state, selected from among the elements Fe, Co, and Ru. Each R ¹ , R ² , R ³ , and R ⁴ is

independently selected from H, a C ₁ -C ₅ alkyl group, an alkyl amino group, and Si(R') ₃ wherein each R' is independently selected from H and a C ₁ -C ₅ alkyl group.

Examples of the metal-containing precursors of Compound (I) include bis(4N-(amino)pent-3-en-2-onato)Nickel(ll), bis(4N- (methylamino)pent-3-en-2-onato) Nickel (II), bis(4N-(ethylamino)pent-3-en- 2-onato) Nickel (II), bis(4N-(isopropylamino)pent-3-en-2-onato) Nickel (II), bis(4N-(n-propylamino)pent-3-en-2-onato) Nickel (II), bis(4N-(n- butylamino)pent-3-en-2-onato) Nickel (II), bis(4N-(isobutylamino)pent-3-en- 2-onato) Nickel (II), bis(4N-(secbutylamino)pent-3-en-2-onato) Nickel (II), bis(4N-(tertbutylamino)pent-3-en-2-onato) Nickel (II), bis(4N-(amino)pent-3- en-2-onato)Cobalt (II), bis(4N-(methylamino)pent-3-en-2-onato) Cobalt (II), bis(4N-(ethylamino)pent-3-en-2-onato) Cobalt (II), bis(4N- (isopropylamino)pent-3-en-2-onato) Cobalt (II), bis(4N-(n- propylamino)pent-3-en-2-onato) Cobalt (II), bis(4N-(n-butylamino)pent-3- en-2-onato) Cobalt (II), bis(4N-(isobutylamino)pent-3-en-2-onato) Cobalt (II), bis(4N-(secbutylamino)pent-3-en-2-onato) Cobalt (II), bis(4N- (tertbutylamino)pent-3-en-2-onato) Cobalt (II), bis(4N-(amino)pent-3-en-2- onato)Palladium (II), bis(4N-(methylamino)pent-3-en-2-onato) Palladium (II), bis(4N-(ethylamino)pent-3-en-2-onato) Palladium (II), bis(4N- (isopropylamino)pent-3-en-2-onato) Palladium (II), bis(4N-(n- propylamino)pent-3-en-2-onato) Palladium (II), bis(4N-(n-butylamino)pent- 3-en-2-onato) Palladium (II), bis(4N-(isobutylamino)pent-3-en-2-onato) Palladium (II), bis(4N-(secbutylamino)pent-3-en-2-onato) Palladium (II), and bis(4N-(tertbutylamino)pent-3-en-2-onato) Palladium (II).

Examples of the metal-containing precursors of Compound (II) include tris(4N-(n-butylamino)pent-3-en-2-onato) iron(lll), tris(4N- (isopropylamino)pent-3-en-2-onato)iron(lll), tris(4N-(ethylamino)pent-3-en- 2-onato)iron(lll), tris(4N-(methylamino)pent-3-en-2-onato)iron(lll), tris(4N- (amino)pent-3-en-2-onato) iron(lll), tris(4N-(n-butylamino)pent-3-en-2- onato)cobalt(lll), tris(4N-(isopropylamino)pent-3-en-2-onato)cobalt(lll), tris(4N-(ethylamino)pent-3-en-2-onato)cobalt(lll), tris(4N- (methylamino)pent-3-en-2-onato)cobalt(lll), tris(4N-(amino)pent-3-en-2- onato) cobalt(lll), tris(4N-(n-butylamino)pent-3-en-2-onato) ruthenium(III), tris(4N-(isopropylamino)pent-3-en-2-onato)ruthernium(lll), tris(4N- (ethylamino)pent-3-en-2-onato)ruthenium(lll), tris(4N-(methylamino)pent-3- en-2-onato)ruthenium(lll), and tris(4N-(amino)pent-3-en-2-onato) ruthenium(lll). bis(4N-(amino)pent-3-en-2-onato)Nickel(ll) may be prepared as described in the literature (Marino Basato, lnorganica Chimica Acta 362 (2009) 2551-2555) by reacting nickel acetate (Ni(OAc) ₂ ) with the ketoimine ligand in alcohol. bis(4N-(Methyl-amino)pent-3-en-2-onato)Nickel(ll) may be prepared as described by Everett, G. W. et al. (Journal of the American Chemical Society (1965), 87(10), 2117-27). bis(4N-(nButyl-amino)pent-3- en-2-onato)Nickel(ll) may be prepared as described by Osowole, A. A et al. (Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry (2002), 32(4), 783-799). Other nickel precursors, bis(4N-(R-amino)pent-3-en-2- onato)Nickel(ll), may be prepared by reacting NiCI ₂ or NiBr ₂ with two equivalents of the lithium salt of the R-ketoimine ligand in tetrahydrofuran. bis(4N-(R-amino)pent-3-en-2-onato)palladium(ll) with R=H, Me, Et, nPr, nBu may be prepared as described in the literature (E. Yoshida, Bulletin of the Chemical Society of Japan (1965), 38(12), 2179-82, G.I. Zharkova, Polyhedron 28 (2009) 2307-2312) by reacting palladium bis- acetylacetonate (Pd(acac) ₂ ) with the corresponding amine, or by reacting PdCI ₂ with the ketoimine ligand.

bis(4N-(R-amino)pent-3-en-2-onato)cobalt(ll) may be prepared according to the published methods (Everett G.W., J. Am. Chem. Soc, 1965, 87 (22), pp 5266-5267).

The disclosed metal-containing precursors may be used to deposit a pure metal (M), metal silicate (M _k Si|), metal oxide (M _n O _m ) or metal oxynitride (M _x N _y O _z ) film (where k, I, m, n, x, y, and z are integers which inclusively range from 1 to 6). These types of films may be useful in

Resistive Random Access Memory (ReRAM) type applications. Some typical film types include a palladium film, cobalt film, nickel film, PdO film, NiO film, CoSi film, NiSi film, and Ni ₂ O ₃ film.

Thin films may be deposited from the disclosed precursors using any deposition methods known to those of skill in the art. Examples of suitable deposition methods include without limitation, conventional CVD, low pressure chemical vapor deposition (LPCVD), plasma enhanced chemical vapor depositions (PECVD) ₁ atomic layer deposition (ALD), pulsed chemical vapor deposition (P-CVD), plasma enhanced atomic layer deposition (PE-ALD), or combinations thereof. The plasma processes may utilize direct or remote plasma sources.

The metal-containing precursor may be supplied either in neat form or in a blend with a suitable solvent, such as ethyl benzene, xylenes, mesitylene, decane, dodecane. The metal-containing precursor may be present in varying concentrations in the solvent.

The neat or blended metal-containing precursor is introduced into a reactor in vapor form. The precursor in vapor form may be produced by vaporizing the neat or blended precursor solution through a conventional vaporization step such as direct vaporization, distillation, or by bubbling. The neat or blended metal-containing precursor may be fed in liquid state to a vaporizer where it is vaporized before it is introduced into the reactor. Alternatively, the neat or blended metal-containing precursor may be vaporized by passing a carrier gas into a container containing the metal- containing precursor or by bubbling the carrier gas into the bis-ketoiminate metal precursor. The carrier gas may include, but is not limited to, Ar, He, N ₂ , and mixtures thereof. Bubbling with a carrier gas may also remove any dissolved oxygen present in the neat or blended precursor solution. The carrier gas and metal-containing precursor are then introduced into the reactor as a vapor.

If necessary, the container of metal-containing precursor may be heated to a temperature that permits the metal-containing precursor to be in its liquid phase and to have a sufficient vapor pressure. The container may be maintained at temperatures in the range of, for example, approximately 0 ⁰ C to approximately 150 ⁰ C. Those skilled in the art recognize that the temperature of the container may be adjusted in a known manner to control the amount of metal-containing precursor vaporized. The reactor may be any enclosure or chamber within a device in which deposition methods take place such as, and without limitation, a parallel-plate type reactor, a cold-wall type reactor, a hot-wall type reactor, a single-wafer reactor, a multi-wafer reactor, or other types of deposition systems under conditions suitable to cause the precursors to react and form the layers.

The reactor contains one or more substrates onto which the thin films will be deposited. The one or more substrates may be any suitable substrate used in semiconductor, photovoltaic, flat panel or LCD-TFT device manufacturing. Examples of suitable substrates include without limitation silicon substrates, silica substrates, silicon nitride substrates, silicon oxy nitride substrates, tungsten substrates, titanium nitride, tantalum nitride, or combinations thereof. Additionally, substrates comprising tungsten or noble metals (e.g. platinum, palladium, rhodium or gold) may be used. The substrate may also have one or more layers of differing materials already deposited upon it from a previous manufacturing step.

The temperature and the pressure within the reactor are held at conditions suitable for vapor depositions. For instance, the pressure in the reactor may be held between about 0.5 mTorr and about 20 Torr, preferably between about 0.2 Torr and 10 Torr, and more preferably between about 1 Torr and 10 Torr, as required per the deposition

parameters. Likewise, the temperature in the reactor may be held between about 50 ⁰ C and about 600 ⁰ C, preferably between about 50° C and about 250° C, and more preferably between about 50° C and about 100° C.

In addition to the metal-containing precursor, a co-reactant is introduced into the reactor. The co-reactant may be an oxidizing gas, such as oxygen, ozone, water, hydrogen peroxide, nitric oxide, nitrogen dioxide, as well as mixtures of any two or more of these. Alternatively, the co- reactant may be a reducing gas, such as hydrogen, ammonia, a silane (e.g. SiH ₄ , Si ₂ H ₆ , Si ₃ H ₈ ), an alkyl silane containing a Si-H bond (e.g. SiH ₂ Me ₂ , SiH ₂ Et ₂ ), N(SiH ₃ )3 _> as well as mixtures of any two or more of these.

Preferably the co-reactant is H ₂ or NH ₃ .

The co-reactant may be treated by a plasma, in order to decompose the co-reactant into its radical form. For instance, the plasma may be generated with a power ranging from about 50 W to about 500 W, preferably from about 100 W to about 200 W. The plasma may be generated or present within the reactor itself. Alternatively, the plasma may generally be at a location removed from the reaction chamber, for instance, in a remotely located plasma system. One of skill in the art will recognize methods and apparatus suitable for such plasma treatment.

The vapor deposition conditions within the chamber allow the metal- containing precursor and the co-reactant to react and form a metal- containing film on the substrate. In some embodiments, Applicants believe that plasma-treating the co-reactant may provide the co-reactant with the energy needed to react with the metal-containing precursor.

Depending on what type of film is desired to be deposited, a second precursor may be introduced into the reactor. The second precursor may be another metal source, such as copper, praseodymium, manganese, ruthenium, titanium, tantalum, bismuth, zirconium, hafnium, lead, niobium, magnesium, aluminum, lanthanum, or mixtures of these. Where a second metal-containing precursor is utilized, the resultant film deposited on the substrate may contain at least two different metal types.

The metal-containing precursor, the co-reactants, and any optional precursors may be introduced into the reactor simultaneously (CVD), sequentially (ALD), or in other combinations. The precursor and the co- reactant may be mixed together to form a co-reactant/precursor mixture, and then introduced to the reactor in mixture form. Alternatively, the precursor and co-reactant may be sequentially introduced into the reaction chamber and purged with an inert gas between the introduction of the precursor and the introduction of the co-reactant. For example, the metal- containing precursor may be introduced in one pulse and two additional metal sources may be introduced together in a separate pulse [modified PE-ALD]. Alternatively, the reactor may already contain the co-reactant species prior to introduction of the metal-containing precursor, the introduction of which may optionally be followed by a second introduction of the co-reactant species. In another alternative, the metal-containing precursor may be introduced to the reactor continuously while other metal sources are introduced by pulse (pulse PECVD). In each example, a pulse may be followed by a purge or evacuation step to remove excess amounts of the component introduced. In each example, the pulse may last for a time period ranging from about 0.01 seconds to about 10 seconds, alternatively from about 0.3 seconds to about 5 seconds, alternatively from about 0.5 seconds to about 2 seconds.

Depending on the particular process parameters, deposition may take place for a varying length of time. Generally, deposition may be allowed to continue as long as desired or necessary to produce a film with the necessary properties. Typical film thicknesses may vary from several hundred angstroms to several hundreds of microns, depending on the specific deposition process. The deposition process may also be

performed as many times as necessary to obtain the desired film.

In one non-limiting exemplary ALD type process, the vapor phase of a metal-containing precursor is introduced into the reactor, where it is contacted with a suitable substrate. Excess metal-containing precursor may then be removed from the reactor by purging and/or evacuating the reactor. A reducing gas (for example, H ₂ ) is introduced into the reactor where it reacts with the absorbed metal-containing precursor in a self-limiting manner. Any excess reducing gas is removed from the reactor by purging and/or evacuating the reactor. If the desired film is a metal film, this two- step process may provide the desired film thickness or may be repeated until a film having the necessary thickness has been obtained.

Alternatively, if the desired film is a bimetal film, the two-step process above may be followed by introduction of the vapor of a second metal-containing precursor into the reactor. The second metal-containing precursor will be selected based on the nature of the bimetal film being deposited. After introduction into the reactor, the second metal-containing precursor is contacted with the substrate. Any excess second metal- containing precursor is removed from the reactor by purging and/or evacuating the reactor. Once again, a reducing gas may be introduced into the reactor to react with the second metal-containing precursor. Excess reducing gas is removed from the reactor by purging and/or evacuating the reactor. If a desired film thickness has been achieved, the process may be terminated. However, if a thicker film is desired, the entire four-step process may be repeated. By alternating the provision of the metal- containing precursor, second metal-containing precursor, and co-reactant, a film of desired composition and thickness can be deposited.

When the co-reactant in this exemplary ALD process is treated with a plasma, the exemplary ALD process becomes an exemplary PE-ALD process. The co-reactant may be treated with plasma prior or subsequent to introduction into the chamber.

The metal-containing films or metal-containing layers resulting from the processes discussed above may include a pure metal (M), metal silicate (M _k Si|), metal oxide (M _n O _m ) or metal oxynitride (M _x N _y O _z ) film wherein M = Mn, Fe, Co, Ni, Ru, and Pd and k, I, m, n, x, y, and z are integers which inclusively range from 1 to 6. Preferably M is Ni, Co, or Pd. Preferably, the metal-containing films are selected from a palladium film, cobalt film, nickel film, PdO film, NiO film, CoSi film, NiSi film, and Ni ₂ O ₃ film. One of ordinary skill in the art will recognize that by judicial selection of the appropriate metal-containing precursor, optional second metal- containing precursors, and co-reactant species, the desired film

composition may be obtained. EXAMPLES

The following non-limiting examples are provided to further illustrate embodiments of the invention. However, the examples are not intended to be all inclusive and are not intended to limit the scope of the inventions described herein.

Example: bis(4N-(alkylamino)pent-3-en-2-onato) Nickel (II)

Synthesis and testing was performed on Compound (I), wherein M = Ni, R ² and R ³ = H, R ⁴ = Me, and R ¹ = Et, nPr, iPr, or nBu and on

Compound (I), wherein M = Ni, R ² and R ³ = H, R ⁴ = iBu, and R ¹ = Et or nPr. High purity solid compounds were obtained. Thermogravimetric analysis of these compounds provided a smooth mass loss and single step transition without any inflection points. All compounds had relatively low residue levels (all less than 10%, with most less than 5%) and melting points (all below 160 ⁰ C, most below 75°C).

ALD deposition of a nickel-containing layer was performed on SiO ₂ , SiH, Au/Pd, and Pd substrates.

Preferred processes and apparatus for practicing the present invention have been described. It will be understood and readily apparent to the skilled artisan that many changes and modifications may be made to the above-described embodiments without departing from the spirit and the scope of the present invention. The foregoing is illustrative only and that other embodiments of the integrated processes and apparatus may be employed without departing from the true scope of the invention defined in the following claims.