KR102592166B1 - Disubstituted alkyne dicobalt hexacarbonyl compounds, method of making and method of use thereof - Google Patents

Abstract

Disclosed herein are cobalt compounds, methods of making cobalt compounds, cobalt compounds used as precursors for depositing cobalt-containing films (e.g., cobalt, cobalt oxide, cobalt nitride, cobalt silicide, etc.); and cobalt films are described. Examples of cobalt precursor compounds include (disubstituted alkyne) dicobalt hexacbonyl compounds. Examples of surfaces for deposition of metal-containing films include, but are not limited to, metals, metal oxides, metal nitrides, and metal silicides. Disubstituted cobalt compounds having alkyl groups such as linear alkyls and branched alkyls are disclosed herein to form cobalt complexes used for selective deposition on certain surfaces and/or excellent film properties such as uniformity, continuity, and low resistivity. Alkyne ligands are described.

Description

DISUBBSTITUTED ALKYNE DICOBALT HEXACARBONYL COMPOUNDS, METHOD OF MAKING AND METHOD OF USE THEREOF}

Cross-references to related applications

This patent application is a continuation-in-part of U.S. Patent Application Serial No. 15/790931, filed on October 23, 2017, which claims the benefit of U.S. Provisional Patent Application Serial No. 62/415,822, filed on November 1, 2016. . This disclosure is incorporated herein by reference.

Described herein are cobalt compounds, methods of making cobalt compounds, and compositions comprising cobalt compounds for use in the deposition of cobalt-containing films.

Cobalt-containing films are widely used in semiconductor or electronic applications. Chemical vapor deposition (CVD) and atomic layer deposition (ALD) are applied as major deposition techniques to create thin films for semiconductor devices. These methods allow the achievement of conformal films (metals, metal oxides, metal nitrides, metal silicides, etc.) through chemical reactions of metal-containing compounds (precursors). Chemical reactions occur on surfaces, which may include metals, metal oxides, metal nitrides, metal silicides, and other surfaces.

Films of transition metals, particularly manganese, iron, cobalt, and ruthenium, are important for a variety of semiconductor or electronic applications. For example, cobalt thin films are of interest due to their high magnetic permittivity. Cobalt-containing thin films are being used as Cu/low-k barriers, passivation layers, and capping layers for very large integrated devices. Cobalt is being considered for replacement of copper in wiring and interconnects of integrated circuits.

Some Co film deposition precursors have been studied in the art.

US 2016/0115588 A1 describes cobalt-containing film forming compositions and their use in film deposition.

WO 2015/127092 A1 discloses a precursor for vapor deposition of cobalt on substrates, such as in ALD and CVD processes for forming interconnects, capping structures, and bulk cobalt conductors, in the fabrication of integrated circuits and thin film products. are listed.

US 2015/0093890 A1 describes metal precursors and methods comprising decomposing the metal precursor and forming a metal from the metal precursor on an integrated circuit device. Metal precursors include (alkyne) dicobalt hexacarbonyl compounds substituted with linear or branched monovalent hydrocarbon groups having 1 to 6 carbon atoms, mononuclear cobalt carbonyl nitrosyl, boron, indium, germanium and tin moieties. selected from the group consisting of cobalt carbonyls bonded to one, cobalt carbonyls bonded to mononuclear or dinuclear allyl, and cobalt compounds comprising nitrogen-based supporting ligands.

WO 2014/118748 A1 describes cobalt compounds, their synthesis, and their use in the deposition of cobalt-containing films.

Keunwoo Lee et al. (Japanese Journal of Applied Physics, 2008, Vol. 47, No. 7, 5396-5399)] used tert-butylacetylene (dicobalt hexacarbonyl) (CCTBA) as a cobalt precursor and H ₂ reactant gas to form the metal. The deposition of cobalt films by organic chemical vapor deposition (MOCVD) is described. Carbon and oxygen impurities in the film decrease with increasing H ₂ partial pressure, but the lowest amount of carbon in the film was 2.8 atomic percent at 150°C. The increase in deposition temperature resulted in high impurity content, and the high film resistivity contributed to excessive thermal decomposition of the CCTBA precursor.

Literature [C. Georgi et al. (J. Mater. Chem. C, 2014, 2, 4676-4682) teaches the formation of Co metal films from (alkyne) dicobalt hexacarbonyl precursors. However, such precursors are not desirable because the films still contain high levels of carbon and/or oxygen causing high resistivity. Additionally, there is no evidence in the literature to support the ability to deposit continuous thin films of Co.

JP2015224227 describes a general synthetic process for producing (alkyne) dicobalt hexacarbonyl compounds. (tert-butyl methyl acetylene) dicobalt hexacarbonyl (CCTMA) is used to produce cobalt films with low resistivity. However, no improvement in membrane properties is seen compared to (tert-butylacetylene) dicobalt hexacarbonyl (CCTBA). Additionally, (tert-butyl methyl acetylene) dicobalt hexacarbonyl is a high melting point (ca. 160° C.) solid. Precursors that are liquid below 100°C, or more preferably below 30°C, may be more desirable.

In general, there are limited options for ALD and CVD precursors that deliver high purity cobalt films or exhibit high selectivity for deposition of a cobalt film on one substrate over another. The development of novel precursors for high purity cobalt thin films and bulk cobalt conductors is needed and desired to improve film uniformity, film continuity, electrical properties, and film deposition selectivity of deposited films.

Disclosed herein are cobalt compounds (or complexes; the terms compounds and complexes are used interchangeably), methods for preparing cobalt compounds, compositions comprising cobalt metal-film precursors used to deposit cobalt-containing films; and cobalt-containing films deposited using cobalt compounds.

Examples of cobalt precursor compounds described herein include, but are not limited to, (alkyne) dicobalt hexacarbonyl compounds. Examples of cobalt-containing films include, but are not limited to, cobalt films, cobalt oxide films, cobalt silicide and cobalt nitride films. Examples of surfaces for deposition of metal-containing films include, but are not limited to, metals, metal oxides, metal nitrides, silicon oxide, and silicon nitride.

For certain applications, better Co film nucleation and lower film resistivity are required compared to (1-2 nm) Co thin films deposited using known Co deposition precursors. As an example, better Co film nucleation and lower film resistivity on TaN are required compared to Co thin films deposited using known Co deposition precursors.

For other applications, selective deposition on specific surfaces is required. For example, selective deposition of cobalt films on copper metal surfaces relative to dielectric surfaces (eg SiO ₂ ).

In one embodiment, the higher thermal stability of cobalt-containing precursors with disubstituted alkyne ligands relative to cobalt-containing precursors with monosubstituted alkyne ligands allows for selective deposition of cobalt-containing films on copper compared to dielectric surfaces. It is used for.

Selective deposition is achieved by using cobalt compounds that have ligands that can selectively interact with one surface over another. Alternatively, selective deposition is achieved by using cobalt compounds that react selectively with one surface over another.

In one embodiment, influence on metal deposition rate and/or metal film purity can be realized by altering the ligand dissociation energy by modification of the coordinated ligands of the Co film precursor. One way to change the ligand dissociation energy is to increase or decrease the size of the functional groups on the ligand. Additionally, the number of functional groups on a ligand can change the ligand dissociation energy. One example of an effect on ligand dissociation energy is the observed change in alkyne ligand dissociation energy from mono- and di-substituted (alkyne) dicobalt hexacarbonyl complexes.

In another embodiment, the melting point of the Co film precursor is lowered by modifying the functional groups on the alkyne ligand.

In one aspect, the invention describes disubstituted alkyne dicobalt carbonyl hexacarbonyl compounds having the formula:

Co ₂ (CO) ₆ (R ₁ C≡CR ₂ );

wherein R ₁ is a tertiary alkyl group and R ₂ is selected from the group consisting of linear alkyl groups having at least two carbon atoms, isopropyl and isobutyl.

In another aspect, the invention describes a method of synthesizing a disubstituted alkyne dicobalt carbonyl hexacarbonyl compound comprising adding the disubstituted alkyne complex to dicobalt octacarbonyl in a solvent,

here,

The disubstituted alkyne complex has the structure R ₁ C≡CR ₂ , where R ₁ is a tertiary alkyl group and R ₂ is a linear alkyl group having at least two carbon atoms, from the group consisting of isopropyl and isobutyl. is selected;

The disubstituted alkyne reacts with dicobalt octacarbonyl in a solvent to form a disubstituted alkyne dicobalt carbonyl hexacarbonyl compound.

In another aspect, the present invention provides a method for depositing a Co film on a substrate in a reactor, comprising:

providing a substrate to the reactor;

providing a Co precursor to the reactor;

contacting the substrate with a Co precursor;

It includes forming a Co-containing film on a substrate,

Here, the Co precursor is a disubstituted alkyne dicobalt carbonyl hexacarbohydrate having the formula Co ₂ (CO) ₆ (R ₁ C≡CR ₂ ), where R ₁ is a tertiary alkyl group and R ₂ is a linear alkyl group. It is a Nyl compound;

The substrate describes a method selected from the group consisting of metals, metal oxides, metal nitrides, silicon oxides, silicon nitrides, and combinations thereof.

In another aspect, the invention relates to a disubstituted alkyne dicobalt carbo having the formula Co ₂ (CO) ₆ (R ₁ C≡CR ₂ ), wherein R ₁ is a tertiary alkyl group and R ₂ is a linear alkyl group. Cobalt containing films deposited by using a nyl hexacarbonyl compound are described.

In another aspect, the present invention provides a method for selectively depositing cobalt on a substrate in a reactor, comprising:

Provide a substrate to the reactor, the substrate comprising at least one patterned dielectric layer and at least one patterned conductive metal layer;

performing pre-treatment to remove contaminants from the surface of the substrate, including at least the surface of at least one patterned conductive metal layer;

providing a Co precursor to the reactor;

contacting the substrate with a Co precursor;

It includes forming a Co-containing film on a substrate,

Here, the Co precursor is a disubstituted polymer having the formula Co ₂ (CO) ₆ (R ₁ C≡CR ₂ ), where R ₁ is a tertiary alkyl group and R ₂ is a linear alkyl group, isopropyl and isobutyl. It is an alkyne dicobalt carbonyl hexacarbonyl compound; The Co-containing film has at least one patterned dielectric layer having a ratio of the thickness of the cobalt-containing film formed on the at least one patterned conductive metal layer to the thickness of the cobalt-containing film formed on the at least one patterned dielectric layer greater than 1. A method for selectively depositing a conductive metal layer is described.

In another aspect, the present invention discloses a semiconductor device having a substrate having a cobalt-containing film deposited according to the method for selectively depositing cobalt on a substrate disclosed herein.

Tertiary alkyl groups include, but are not limited to, tert-butyl and tert-amyl; Linear alkyl groups include, but are not limited to, n-ethyl, n-propyl, and n-butyl, n-pentyl, and n-hexyl.

Disubstituted alkyne dicobalt carbonyl hexacarbonyl compounds include (2,2-dimethyl-3-heptyne) dicobalt hexacarbonyl (CCTPA), (2,2,6-trimethyl-3-heptyne) dicobalt hexacarbonyl (CCTIBA); (2,2-dimethyl-3-octyne) dicobalt hexacarbonyl (CCTNBA); (2,2-dimethyl-3-decyne) dicobalt hexacarbonyl (CCTHA), and (tert-butylmethylacetylene) dicobalt hexacarbonyl (CCTMA).

Cobalt-containing films are preferably deposited by using disubstituted alkyne dicobalt carbonyl hexacarbonyl compounds that are in liquid form at temperatures below 30°C.

Cobalt-containing films include, but are not limited to, cobalt films, cobalt oxide films, cobalt silicide films, and cobalt nitride films. The cobalt-containing film contains less than 2.5 atomic percent carbon, preferably less than 1.5 atomic percent carbon, and more preferably less than 0.5 atomic percent carbon.

The invention will be described below in conjunction with the accompanying drawings, in which like numbers represent like elements:
Figure 1 shows a mono-substituted alkyne cobalt complex, (3,3-dimethyl-1-butyne) dicobalt hexacarbonyl (CCTBA), and a series of di-substituted alkyne cobalt complexes when measured under nitrogen flow. , (tert-butyl R alkyne) dicobalt hexacarbonyl, where R is methyl (CCTMA), n-propyl (CCTPA), n-butyl (CCTNBA), and n-hexyl (CCTHA) It shows an overlay of gravimetric analysis (TGA) data.
Figure 2 is the isothermal thermogravimetric weight for (2,2-dimethyl-3-octyne) dicobalt hexacarbonyl (cobalt carbonyl tert-butyl N-butyl acetylene-CCTNBA), measured at 75°C under nitrogen flow. This shows measurement analysis (TGA) data.
Figure 3 shows (3,3-dimethyl-1-butyne) dicobalt hexacarbonyl (CCTBA) and (2,2-dimethyl-3-octyne) dicobalt hexacarbonyl, as measured in a sealed SS316 DSC pan. A comparison of differential scanning calorimetry (DSC) data for Neil (CCTNBA) is shown.
Figure 4 shows Co film resistivity versus film thickness for (3,3-dimethyl-1-butyne) dicobalt hexacarbonyl (CCTBA) and (4,4-dimethyl-2-pentyne dicobalt hexacarbonyl (CCTMA). It shows an overlay of .
Figure 5 shows transmission electron microscopy (TEM) images of cobalt films deposited on SiO ₂ using 4,4-dimethyl-2-pentyne dicobalt hexacarbonyl (CCTMA) as the Co film precursor.
Figure 6 shows the SiO ₂ phase using (3,3-dimethyl-1-butyne) dicobalt hexacarbonyl (CCTBA) and 4,4-dimethyl-2-pentyne dicobalt hexacarbonyl (CCTMA) as Co film precursors. X-ray photoelectron spectroscopy (XPS) data of cobalt films deposited on is shown.

The detailed description that follows provides preferred exemplary embodiments only and is not intended to limit the scope, applicability, or configuration of the invention. Rather, the detailed description of the preferred exemplary embodiments that follows will provide those skilled in the art with enabling instructions for practicing the preferred exemplary embodiments of the invention. Various changes may be made in the function and arrangement of components without departing from the spirit and scope of the invention, as set forth in the appended claims.

In the claims, letters may be used to identify claimed method steps (eg, a, b, and c). These letters are used to help refer to method steps and are not intended to specify the order in which the claimed steps are performed, unless the order is described in detail in the claims and is only described to some extent. .

Disclosed herein are cobalt compounds, methods of making cobalt compounds, and cobalt metal-film precursors used to deposit cobalt-containing films (e.g., cobalt, cobalt oxide, cobalt nitride, cobalt silicide films, etc.). Compositions comprising are described.

Examples of cobalt precursor compounds include, but are not limited to, (alkyne) dicobalt hexacarbonyl compounds.

Examples of surfaces for deposition of metal-containing films include, but are not limited to, metals, metal oxides, metal nitrides, metal silicides, silicon, silicon oxide, and silicon nitride.

Examples of cobalt-containing films include, but are not limited to, cobalt, cobalt oxide, cobalt silicide, and cobalt nitride.

One aspect of the invention is a compound having the formula Co ₂ (CO) ₆ (R ₁ C≡CR ₂ ), where R ₁ is a tertiary alkyl group and R ₂ is linear hydrocarbons, branched hydrocarbons, and combinations thereof. These are cobalt compounds such as (alkyne) dicobalt hexacarbonyl compounds having (selected from the group consisting of).

In one embodiment of the invention, the alkyl groups on the alkyne ligand are selected to lower the melting point of the Co film precursor. The Co film precursor is liquid at the delivery temperature, more preferably at ambient temperature, and most preferably at a temperature below 30°C.

In another embodiment of the invention, the Co film precursor is liquid at ambient temperature.

In one embodiment of the invention, the alkyl groups on the alkyne ligand are selected to lower the Ligand Dissociation Energy (LDE).

In another embodiment of the invention, the alkyl groups on the alkyne ligands are selected to inhibit polymerization of the alkyne ligands during the Co film deposition process.

In another embodiment of the invention, (alkyne) dicobalt carbonyl compounds are synthesized by reacting alkynes with dicobalt octacarbonyl in a suitable solvent (e.g. hexanes, tetrahydrofuran, diethyl ether, toluene). .

(Alkyne) dicobalt carbonyl compounds can be purified by distillation under reduced pressure. Alternatively, (alkyne) dicobalt hexacarbonyl compounds can be purified by chromatography on a support such as alumina or silica. Solid (alkyne) dicobalt carbonyl compounds can be purified by sublimation under reduced pressure.

One embodiment of the invention is a compound having the formula Co ₂ (CO) ₆ (R ₁ C≡CR ₂ ), where R ₁ is a tertiary alkyl group and R ₂ is a linear alkyl group having at least two carbon atoms. (Alkyne) dicobalt hexacarbonyl compounds. Examples of tertiary alkyl groups include, but are not limited to, tert-butyl and tert-amyl. Examples of linear alkyl groups having at least two carbon atoms are, but are not limited to, n-ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-pentyl, and n-hexyl.

The combination of R ₁ and R ₂ groups is selected to lower the melting point of the desired cobalt complex. The combination of R ₁ and R ₂ groups is also selected to provide liquid (alkyne) dicobalt hexacarbonyl compounds with improved thermal stability. Liquid (alkyne) dicobalt hexacarbonyl precursors, such as CCTBA, are known in the art, but these precursors have limited thermal stability. Thermogravimetric analysis is often used to compare non-volatile residues formed during evaporation of volatile precursors.

Figure 1 shows a mono-substituted alkyne cobalt complex, (3,3-dimethyl-1-butyne) dicobalt hexacarbonyl (CCTBA), and a series of di-substituted alkyne cobalt complexes when measured under nitrogen flow. , (tert-butyl R alkyne) dicobalt hexacarbonyl, where R is methyl (CCTMA), n-propyl (CCTPA), n-butyl (CCTNBA), and n-hexyl (CCTHA) This shows an overlay of gravimetric analysis (TGA) data.

TGA analysis in Figure 1 shows that CCTMA, CCTPA and CCTNBA are more thermally stable precursors with lower non-volatile residuals compared to CCTBA.

Precursors in which R ₁ is a tertiary alkyl group and R ₂ is a linear alkyl group have a lower non-volatile residue compared to CCTBA at the same temperature. The only precursor with a similarly higher non-volatile residue compared to CCTBA is CCTHA, but this precursor evaporates at ~50° C. higher compared to CCTBA due to its lower vapor pressure. Accordingly, it still has better thermal stability compared to CCTBA, although the end point of evaporation is shifted to higher temperatures, around 50° C., since the same non-volatile residue is observed. Differential scanning calorimetry is often used to compare the onset of thermal decomposition of precursors.

Figure 3 shows (3,3-dimethyl-1-butyne) dicobalt hexacarbonyl (CCTBA) and (2,2-dimethyl-3-octyne) dicobalt hexacarbonyl, as measured in a sealed SS316 DSC pan. A comparison of differential scanning calorimetry (DSC) data from Neil (CCTNBA) is shown.

Figure 3 shows that the liquid precursor of the present invention, CCTNBA, has a higher onset decomposition temperature compared to CCTBA. The comparison shows that CCTBA decomposes exothermically at lower temperatures and CCTNBA decomposes endothermically at higher temperatures, resulting in improved thermal stability of CCTNBA compared to CCTBA.

Thermal stability of precursors is very important for reliable delivery of precursors to the deposition tool. Since CCTBA exhibits non-volatile residues during evaporation and exothermic decomposition at relatively low temperatures, its evaporation from the bubbler causes accumulation of non-volatile residues in the bubbler and low utilization of CCTBA in the bubbler. . The precursors of the present invention are expected to provide much better utilization in bubblers and better shelf life on deposition tools compared to CCTBA.

The reaction of 4,4-dimethyl-2-pentyne with dicobalt octacarbonyl results in replacement of the two CO ligands and formation of a dicobalt compound with a bridging 4,4-dimethyl-2-pentyne ligand. The chemical structure of the bridging 4,4-dimethyl-2-pentyne ligand indicates that the ligand has a tert-butyl group on one side of the carbon-carbon triple bond and a methyl group on the other side of the carbon-carbon triple bond. :

(4,4-dimethyl-2-pentyne) dicobalt hexacarbonyl complex (CCTMA) has the structure:

(4,4-dimethyl-2-pentyne) dicobalt hexacarbonyl complex is a solid at ambient temperature. The melting point of (4,4-dimethyl-2-pentyne) dicobalt hexacarbonyl is approximately 160° C., which is not a suitable delivery temperature.

Differential scanning calorimetry (DSC) data for (4,4-dimethyl-2-pentyne) dicobalt hexacarbonyl indicate that the onset of thermal decomposition occurs in the temperature range of 180 to 200°C. Accordingly, it is not possible to deliver (4,4-dimethyl-2-pentyne) dicobalt hexacarbonyl to a Co film deposition process together with a liquid Co film precursor.

In one example, the reaction of 2,2-dimethyl-3-octyne with dicobalt octacarbonyl results in displacement of the two CO ligands and formation of a dicobalt compound with a bridging 2,2-dimethyl-3-octyne ligand. It causes. The chemical structure of the bridging 2,2-dimethyl-3-octyne ligand is such that the ligand has a tert-butyl group on one side of the carbon-carbon triple bond and an n-butyl group on the other side of the carbon-carbon triple bond. Indicates having:

The resulting volatile (2,2-dimethyl-3-octyne) dicobalt hexacarbonyl complex can be distilled under vacuum to yield a dark red oil. This Co film precursor is liquid at room temperature and can be delivered to the Co film deposition process together with the Co film precursor in a liquid state. The melting point of (2,2-dimethyl-3-octyne) dicobalt hexacarbonyl is below -20°C.

In another example, the reaction of 2,2,6-trimethyl-3-heptine with dicobalt octacarbonyl results in displacement of two CO ligands and dicobalt with a bridging 2,2,6-trimethyl-3-heptine ligand. causes the formation of compounds. The chemical structure of the bridging 2,2,6-trimethyl-3-heptine ligand is that the ligand has a tert-butyl group on one side of the carbon-carbon triple bond and an iso-butyl group on the other side of the carbon-carbon triple bond. Indicates having a spirit:

(2,2,6-trimethyl-3-heptyne) dicobalt hexacarbonyl complex is a solid at ambient temperature. The melting point of (2,2,6-trimethyl-3-heptyne) dicobalt hexacarbonyl is higher than 25°C.

Accordingly, even minimal changes in the structure of the alkyl ligand, such as changing an n-butyl group to an iso-butyl group, have an effect on the melting point of (alkyne) dicobalt hexacarbonyl.

The melting point of (tert-butyl n-alkyl acetylene) dicobalt hexacarbonyl complexes generally decreases as the number of carbon atoms increases. However, as shown in Table I, the effect of number of carbon atoms versus melting point is non-linear.

Table I: Melting points of a series of (tert-butyl n-alkyl acetylene) dicobalt hexacarbonyl complexes

The cobalt complexes or compositions described herein are well suited for use as volatile precursors for ALD, CVD, pulsed CVD, plasma enhanced ALD (PEALD) or plasma enhanced CVD (PECVD) for the fabrication of semiconductor type microelectronic devices. do. Examples of suitable deposition processes for the methods described herein include cyclic CVD (CCVD), metal organic CVD (MOCVD), thermal chemical vapor deposition, plasma enhanced chemical vapor deposition (“PECVD”), high density PECVD, photon assisted CVD, Includes plasma-photon assisted (“PPECVD”), cryogenic chemical vapor deposition, chemically assisted vapor deposition, hot-filament chemical vapor deposition, CVD of liquid polymer precursors, deposition from supercritical fluids, and low energy CVD (LECVD). , but is not limited to this. In certain embodiments, cobalt-containing films are deposited via atomic layer deposition (ALD), plasma enhanced ALD (PEALD), or plasma enhanced cyclic CVD (PECCVD) processes. As used herein, the term “chemical vapor deposition processes” refers to any process in which a substrate is exposed to one or more volatile precursors, which react and/or decompose on the substrate surface to produce the desired deposition. As used herein, the term “atomic layer deposition process” refers to a self-limiting (e.g., constant amount of film material deposited in each reaction cycle), depositing films of materials on substrates of varying compositions. Refers to sequential surface chemistry. Although the precursors, reagents, and sources used herein may sometimes be described as "gaseous," the precursors are transported with or without an inert gas to the reactor through direct vaporization, bubbling, or sublimation. It is understood that it may be either a liquid or a solid. In some cases, vaporized precursors may proceed through a plasma generator. In one embodiment, the metal-containing film is deposited using an ALD process. In another embodiment, the metal-containing film is deposited using a CCVD process. In a further embodiment, the metal-containing film is deposited using a thermal CVD process. As used herein, the term “reactor” includes, but is not limited to, a reaction chamber or a deposition chamber.

In certain embodiments, the methods described herein prevent pre-reaction of metal precursors by using ADD or CCVD methods, which separate the precursors before and/or during introduction to the reactor.

In certain embodiments, the method uses a reducing agent. The reducing agent is usually introduced in gaseous form. Examples of suitable reducing agents include hydrogen gas, hydrogen plasma, remote hydrogen plasma, silanes (i.e. diethylsilane, ethylsilane, dimethylsilane, phenylsilane, silane, disilane, aminosilane, chlorosilane), borane ( i.e., borane, diborane), allanes, germanes, hydrazines, ammonia, or mixtures thereof, but are not limited thereto.

Deposition methods described herein may include one or more purge gases. The purge gas is used to purge unconsumed reactants and/or reaction by-products, and is an inert gas that does not react with the precursors. Exemplary purge gases include, but are not limited to, argon (Ar), nitrogen (N ₂ ), helium (He), neon, and mixtures thereof. In certain embodiments, a purge gas, such as Ar, is supplied to the reactor at a flow rate ranging from about 10 to about 2000 sccm for about 0.1 to 10000 seconds to remove unreacted material and any by-products that may remain in the reactor. purge.

Energy may be applied to at least one of the precursor, reducing agent, other precursors, or combinations thereof to induce a reaction and form a metal-containing film or coating on the substrate. Such energy may be provided by, but not limited to, thermal, plasma, pulsed plasma, helicon plasma, high density plasma, inductively coupled plasma, X-ray, e-beam, photon, remote plasma methods, and combinations thereof. You can. In certain embodiments, a secondary RF frequency source can be used to modify the plasma characteristics at the substrate surface. In embodiments where the deposition involves plasma, the plasma-generating process can be a direct plasma-generating process, where the plasma is generated directly in the reactor, or alternatively, a remote plasma-generating process, where the plasma is generated outside the reactor and fed into the reactor. May include generation processes.

Cobalt precursors can be delivered to a reaction chamber, such as a CVD or ALD reactor, in a variety of ways. In one embodiment, a liquid delivery system may be used. In an alternative embodiment, a combined liquid delivery and flash vaporization process unit, such as a turbo vaporizer manufactured by MSP Corporation (Shoreview, Minn.), can be used to deliver low volatility materials volumetrically, which can be used to deliver the precursors. This results in reproducible transport and deposition without thermal decomposition. The precursor compositions described in this application can be effectively used as source reagents in DLI mode to provide a vapor stream of these cobalt precursors to an ALD or CVD reactor.

In certain embodiments, these compositions include the use of hydrocarbon solvents, which are particularly desirable due to their ability to dry to sub ppm water levels. Exemplary hydrocarbon solvents that can be used in the present invention include toluene, mesitylene, cumene (isopropylbenzene), p-cymene (4-isopropyl toluene), 1,3-diisopropylbenzene, octane, dodecane, 1, Includes, but is not limited to, 2,4-trimethylcyclohexane, n-butylcyclohexane, and decahydronaphthalene (decalin). The precursor compositions of the present application can also be stored and used in stainless steel containers. In certain embodiments, the hydrocarbon solvent in the composition is a high boiling point solvent or has a boiling point of 100° C. or higher. The cobalt precursor compositions of the present application can also be mixed with other suitable metal precursors and mixtures used to deliver both metals simultaneously for the growth of binary metal-containing films.

In certain embodiments, gas lines connecting the precursor canisters to the reaction chamber are heated to one or more temperatures depending on process requirements, and the vessel containing the composition is maintained at one or more temperatures for bubbling. In other embodiments, the compositional cobalt precursor is injected into a vaporizer maintained at one or more temperatures for direct liquid injection.

A flow of argon and/or other gases may be used as a carrier gas to help deliver the vapor of at least one cobalt precursor to the reaction chamber during precursor pulsing. In certain embodiments, the reaction chamber process pressure is 1 to 50 torr, preferably 5 to 20 torr.

For many applications, high purity Co metal films are a requirement for reasons including, but not limited to, low resistivity. In the art, it is widely known that certain impurities in Co metal films can increase resistivity. These impurities include, but are not limited to, carbon, oxygen, and nitrogen. Accordingly, suitable Co metal deposition precursors must be designed to limit the amount of carbon present in the deposited Co metal films.

Cobalt compounds with the structure (alkyne) dicobalt hexacarbonyl have been studied for use as Co deposition precursors. Literature [C. Georgi et al. (J. Mater. Chem. C, 2014, 2, 4676-4682)] has the formula Co ₂ (CO) ₆ (R ₁ C≡CR ₂ ) (where R ₁ or R ₂ is tertiary (e.g., Despite large differences in the identification of the R ₁ and R ₂ groups in complexes (which may be trimethylsilyl), linear (e.g., n-propyl), or hydrogen), there are high levels of carbon and oxygen in the bulk films. Both exist. In this study, carbon contents ranged from 2.5 to 36.5 mol% and oxygen contents ranged from 0.8 to 34.4 mol%. The lowest amount of carbon in this series is 2.5 atomic percent for the high melting point solid precursor when R ₁ and R ₂ are trimethylsilyl. Accordingly, the amount of carbon in the cobalt film deposited using these precursors was determined by Keunwoo Lee et al. in Japanese Journal of Applied Physics, 2008, Vol. 47, no. 7, 5396-5399, the amount of carbon in the cobalt film deposited from CCTBA was similar.

The carbon and oxygen content in the deposited film should preferably be less than 2.5 atomic %, or more preferably less than 1.5 atomic %, and most preferably less than 0.5 atomic %. The low carbon content of the film allows obtaining cobalt metal films with low resistivity without requiring post-deposition treatments such as exposure of the films to hydrogen or ammonia plasma.

Substrate temperature is an important process variable in the deposition of high quality cobalt films. Typical substrate temperatures range from about 100°C to about 250°C. Higher temperatures can promote higher film growth rates. Accordingly, it is desirable to find Co film precursors that can deposit Co films at high temperatures without increasing the level of impurities such as carbon and oxygen.

In the field of metal-containing film deposition, it is generally accepted that precursors that are liquid under metal-containing film deposition process conditions are preferred over precursors that are solid under metal-containing film deposition process conditions. Reasons include, but are not limited to, the ability to bubble a carrier gas through the metal-containing film precursor under suitable process conditions. The ability to bubble a carrier gas through a metal-containing film precursor can result in more uniform delivery of the precursor to the metal-containing film deposition process compared to sublimation of solid precursors.

Unexpectedly, the applicant discovered that the precursors of the present invention, i.e., of the formula Co ₂ (CO) ₆ (R ₁ C≡CR ₂ ), where R ₁ is a tertiary alkyl group and R ₂ are linear hydrocarbons, branched It has been discovered that (alkyne) dicobalt hexacarbonyl compounds with (selected from the group consisting of hydrocarbons, and combinations thereof) provide cobalt films with carbon levels as low as 0.4 atomic percent. Without wishing to be bound by theory, it is believed that the bulky tertiary alkyl group R ₁ is required to lower the alkyne ligand dissociation energy from the cobalt center, thereby resulting in a cleaner removal of the organic ligand from the cobalt center. Accordingly, Co film precursors such as (2,2-dimethyl-3-octyne) dicobalt hexacarbonyl (cobalt carbonyl tert-butyl N-butyl acetylene, CCTNBA) are expected to exhibit low carbon levels in the deposited films. It would be expected.

As an example, the ligand dissociation energies for alkyl ligand removal and CO ligand removal were calculated for a series of (alkyne) dicobalt hexacarbonyl compounds. Using BioViaMaterials Studio 7.0 (BLYP/DNP/AE, 4.4 Angstrom orbital cutoff) for calculation of reaction energetics at 0 K, with manual spin state optimization, Table II shows a series of (alkyne) dicobalt hexates. Calculated reaction energies for removal of alkyne ligands and CO ligands from carbonyl complexes are shown. Table II shows strong steric effects for alkyl groups on alkyne ligands.

Table II

Calculated reaction energies for removal of alkyl ligands and CO ligands

Table II illustrates the significant effect of steric bulk on alkyne ligand dissociation energy (LDE). For example, the LDE for the alkyne ligand in CCNBA is significantly higher compared to the LDE for the alkyne ligand in isomeric CCTBA. Additionally, the number of functional groups on the ligand can change the LDE for alkyne ligands. For linear alkyl groups, the calculations shown in Table II show a moderate degree of LDE for the (disubstituted alkyne) dicobalt hexacarbonyl complex, CCMPA, compared to the (mono-substituted alkyne) dicobalt hexacarbonyl complex, CCNBA. It suggests a moderate decrease.

Without wishing to be bound by theory, it is believed that R ₂ is selected from the group consisting of linear hydrocarbons, branched hydrocarbons, and combinations thereof, and provides thermal stability to this family of precursors. For example, one possible CCTBA degradation route is through oligomerization of the mono-substituted alkyne ligand, tert-butylacetylene. The disubstituted acetylenes of the present invention are expected to have low oligomerization rates. This property is beneficial in preventing the accumulation of degradation by-products during precursor delivery. In other embodiments, cobalt-containing films are Co ₂ (CO) ₆ (R ₁ C≡CR ₂ ), where R ₁ is a tertiary alkyl group and R ₂ is a linear alkyl group having at least two carbon atoms. , R ₂ is isopropyl or isobutyl). Examples of tertiary alkyl groups are, but are not limited to, tert-butyl and tert-amyl. Examples of linear alkyl groups having at least two carbon atoms are, but are not limited to, n-ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl. (2,2-dimethyl-3-octyne) dicobalt hexacarbonyl (CCTNBA) is a preferred precursor because it is liquid at room temperature, with relatively high vapor pressure and good thermal stability. Cobalt films can be grown on silicon, silicon oxide, PVD TaN and copper substrates using the described Co complexes as deposition precursors in a reactor.

Co film thickness can be measured by X-ray fluorescence (XRF), scanning electron microscopy (SEM), and transmission electron microscopy.

In certain embodiments, precursors with disubstituted alkyne ligands are used to selectively deposit cobalt-containing films on conductive metal surfaces compared to dielectric surfaces.

Conductive metal surfaces may include copper, cobalt, and ruthenium. The conductive metal surface may be pre-treated prior to the deposition process to remove contaminants from the conductive metal surface. Contaminants may include organic impurities and metal oxides. The pre-treatment process heats the structure comprising the conductive metal surface in the presence of a reducing gas, for example hydrogen or ammonia, at 100 to 500°C and/or heats the structure comprising the conductive metal surface at 100 to 500°C. It may include exposure to hydrogen plasma, ammonia plasma, nitrogen plasma, argon plasma, or helium plasma.

The dielectric surface may include silicon dioxide, fluorosilicate glass (FSG), organosilicate glass (OSG), carbon doped oxide (CDO), or a porous low-K material. Examples of low K dielectric materials used in this process include porous OSG (organosilicate glass).

A structure comprising a conductive metal surface and a dielectric surface is

a) at least one patterned dielectric layer with embedded conductive metal features (eg, copper, cobalt, ruthenium or metal alloy); and

b) at least a cobalt layer selectively deposited on the conductive metal features.

The structure may further have a metal barrier layer formed between the patterned dielectric layer and the embedded conductive metal feature. The metal barrier layer includes materials such as tantalum, tantalum nitride, titanium, titanium nitride, cobalt, ruthenium, and other advanced barrier materials that prevent diffusion of copper into the dielectric material.

Selectivity can be measured by comparing the thickness of silicon oxide and a cobalt-containing film deposited on copper under the same process conditions. The ratio of the cobalt-containing film thickness on copper to the silicon oxide thickness, when measured by XRF, SEM, or TEM, is preferably >10:1, more preferably >50:1, and most preferably > It is 250:1.

In one embodiment, cobalt films deposited from the cobalt precursors of the present invention are annealed to lower the resistivity of the films. In the annealing process, the structure comprising the cobalt film is heated to 300 to 500° C., preferably 375 to 425° C., in a flow of gas containing 3 to 15% by volume hydrogen.

Example

The following examples describe methods of preparing the described Co complexes and the deposition of Co-containing films using the described Co complexes as Co precursors.

In the deposition process, Co precursors were delivered to the reactor chamber by passing 50 sccm argon through stainless steel vessels filled with Co precursors. The vessel temperature was varied between 30°C and 60°C to achieve sufficient vapor pressure of the precursor. Wafer temperature varied from 125°C to 200°C. The reactor chamber pressure varied from 5 to 20 torr. Deposition tests were performed in the presence of 500 to 1000 sccm of hydrogen or argon flow. The deposition time varied from 20 seconds to 20 minutes to achieve different thicknesses of Co films.

Cobalt films were grown on silicon, silicon oxide, PVD TaN and copper substrates using a CN-1 showerhead style reactor.

Co film thickness was measured by X-ray fluorescence (XRF) and scanning electron microscopy (SEM).

Example 1 (Comparison)

Synthesis and thermal properties of (methyl n-propylacetylene) dicobalt hexacarbonyl (CCMPA)/( ⁿ Pr)CC(Me)(Co) ₂ (CO) ₆

In a ventilated hood, a solution of 2-hexyne (4.34 g, 53 mmol) in hexanes (50 mL) was reacted with Co ₂ (CO) ₈ (17 g, 48 mmol) in hexanes (100 mL) over 30 min. mmol) was added to the solution. CO evolution was observed upon addition of each aliquot of 2-hexene solution. The resulting dark red/brown solution was stirred at room temperature for 4 hours. The volatiles were removed under vacuum at room temperature to give a dark red oil. The oil was filtered through a pad of Celite 545 and distilled under vacuum. The product was heated at 40°C and ca. Distillation began at 200 millitorr pressure. The temperature was slowly raised to 50°C (pressure 140 millitorr). The temperature was slowly increased to 55°C (pressure 120 millitorr). The temperature remained at 55°C until distillation was complete. After evaporating all the volatile CCMPA, a very small amount of black solid was coated on the reboiler. The dark red oil obtained was analyzed by IR, NMR, TGA, and DSC.

The solution IR of pure CCMPA is ca. It showed 0.07% tetracobalt dodecacarbonyl (1860 cm ^-1 ) and no other substantial metal carbonyl peaks.

The ¹ H NMR spectrum of CCMPA showed four sets of resonances with expected 2/3/2/3 intensities matching the molecular structure [2.5 ppm (m), 2H; 2.3 ppm(s), 3H; 1.5 ppm (m), 2H; 0.8 ppm (m), 3H].

Dynamic thermogravimetric analysis (TGA) of CCMPA was measured under nitrogen flow.

Possibly directing the formation of less volatile decomposition products, ca. It was shown that the evaporation rate changes at 155°C. The final non-volatile residual weight was 3.1% of the original weight.

Example 2 (Comparison)

Deposition of Co films from CCMPA

The Co precursor, CCMPA, was synthesized and purified as described in Comparative Example 1. The experimental conditions for cobalt film deposition were precursor vessel temperature of 35°C, wafer temperature of 150°C, chamber pressure of 10 torr, and hydrogen flow rate of 500 sccm.

Cobalt film thickness and film properties compared to films deposited using the same conditions but using CCTBA as the precursor are shown in Table III. For both precursors, the deposition time was 10 minutes.

Table III

Increasing the deposition temperature to 175°C resulted in higher impurities for both precursors. Accordingly, this comparative example shows that the Co ₂ (CO) ₆ (nPrC≡CMe) precursor, where R ₁ and R ₂ are not tertiary alkyl groups, has a significantly higher carbon yield compared to the cobalt film using the CCTBA precursor. A cobalt film having an amount (28.2 atomic %) was provided.

Example 3

Synthesis and thermal properties of (tert-butylmethylacetylene) dicobalt hexacarbonyl (CCTMA)/(tBu)CC(Me)(Co) ₂ (CO) ₆

In a ventilated hood, a solution of 4,4-dimethyl-2-pentyne (5 g, 52 mmol) in hexanes (50 mL) was reacted with Co ₂ (CO) ₈ (17.0 g) in hexanes (150 mL) over 30 min. , 48 mmol) was added to the solution. CO evolution was observed upon addition of each aliquot of 4,4-dimethyl-2-pentyne solution. The resulting dark red/brown solution was stirred at room temperature for 4 hours. The volatiles were removed under vacuum at room temperature to give a dark brown solid. The solid was dissolved in ˜25 mL of hexanes and filtered through a Celite 545 pad. Upon removal of the hexanes under vacuum, a dark red-brown solid was obtained. The solid was purified by sublimation at 35° C. (0.6 mTorr) under vacuum.

Solution IR analysis (10% hexane solution) showed one peak for the carbonyl ligands with no peaks corresponding to the dicobalt octacarbonyl starting material.

The ¹ H NMR spectrum of CCTMA showed two sets of resonances with expected 1:3 intensities matching the molecular structure [2.3 ppm (s), 1H; 1.1 ppm(s), 3H].

Dynamic thermogravimetric analysis (TGA) of CCTMA was measured under nitrogen flow and is shown in Figure 1 along with data for other cobalt complexes in the present invention.

Possibly indicating melting point, ca. It was found that the evaporation rate increased at 160℃.

The final non-volatile residual weight was 0.6% of the original weight. Differential scanning calorimetry of CCTMA samples demonstrated a melting point of ~160°C.

Example 4

Preparation of (2,2-dimethyl-3-heptyne) dicobalt hexacarbonyl (cobalt carbonyl tert-butyl propyl acetylene-CCTPA)

In a well-ventilated hood, a solution of 2,2-dimethyl-3-heptine (5 g, 40 mmol) in hexanes (25 mL) was incubated with Co ₂ (CO) ₈ ( 12.3 g, 36 mmol) was added to the solution. Upon addition of each aliquot of 2,2-dimethyl-3-heptine solution, CO evolution was observed. The resulting dark red-brown solution was stirred at room temperature for 16 hours. The volatiles were removed under vacuum at room temperature to yield a dark brown mixture of solids and liquid. The solid/liquid mixture was dissolved in ˜50 mL of hexanes and filtered through a Celite 545 pad. Upon removal of the hexanes under vacuum, a dark brown mixture of solids and liquid was obtained. The crude material was dissolved in 10 mL of hexanes. A chromatography column (~3 cm diameter) was packed with 8 inches of neutral activated alumina using pure hexanes as the eluent. The crude material solution was placed on the column and eluted using hexanes. A dark brown band remained on the top of the column, and a bright red band quickly moved down the column with hexane. The red bands were collected and evacuated to dryness, yielding a sticky dark red solid.

¹ H NMR and ¹³ C NMR analysis of the solid shows resonances consistent with the expected product.

IR analysis in hexane solution showed two strong bands for metal-bound CO ligands at 2050 and 2087 cm ^-1 .

Example 5

Synthesis of 2,2-dimethyl-3-decyne (tert-butyl n-hexyl acetylene)

In a nitrogen glovebox, tert-butylacetylene (3,3-dimethyl-1) was added by placing tert-butylacetylene (5.0 g, 61 mmol) in a 500 mL Schlenk flask with 100 mL of anhydrous THF. -Butyne) solution was prepared. To a 60 mL addition funnel was added 24 mL of 2.5M n-butyllithium in hexanes (60 mmol). The flask and addition funnel were removed from the glovebox and assembled in a ventilation hood. The tert-butylacetylene solution was cooled to 0°C. The n-butyllithium solution was added dropwise to the tert-butylacetylene solution over 20 minutes while stirring. After the addition was complete, the colorless solution was allowed to warm to room temperature over 2 hours with stirring. The obtained solution was cooled to 0°C. 1-iodohexane (11.4 g, 54 mmol) and 40 mL anhydrous THF were added to a 60 mL addition funnel. This solution was added dropwise to the cooled lithium tert-butylacetylide solution over 30 minutes while stirring. The solution was warmed to room temperature and stirred at room temperature for 2.5 days. The resulting colorless solution was sampled by GC-MS, which showed ~95% yield of the desired product. Under nitrogen, deionized water (100 mL) was added to the solution to form a two-phase mixture. Afterwards, an additional 100 mL of hexane was added to the two-phase mixture to promote phase separation. After 10 minutes of stirring, the two phases were separated. The organic layer was extracted with a second 100 mL aliquot of deionized water before separation. The two water washes were combined and extracted with 50 mL of hexanes. The organic fractions were combined and dried by stirring over anhydrous magnesium sulfate for 30 minutes. Magnesium sulfate was removed by filtration through a glass frit. The resulting clear, colorless solution was distilled under static vacuum to remove the solvents. Maintaining the reboiler temperature at 20°C, the condenser at -10°C, and the collection flask at -78°C (dry ice), the distillation apparatus was evacuated to -10 torr and disconnected from the vacuum line by closing the valve. . Solvents were removed over ˜1.5 hours, leaving ˜10 cc of colorless liquid in the reboiler. The collection flask was removed and another, smaller collection flask was installed. This flask was cooled to -78°C and the condenser temperature was set to -2°C. Approximately half of the remaining liquid was transferred to a collection flask under dynamic vacuum (~1 torr).

GC-MS analysis showed that 2,2-dimethyl-3-decyne was isolated with greater than 99% purity.

Example 6

Synthesis of (2,2-dimethyl-3-decyne) dicobalt hexacarbonyl (cobalt carbonyl tert-butyl n-hexyl acetylene-CCTHA)

In a ventilated hood, a solution of 2,2-dimethyl-3-decyne (4.15 g, 25 mmol) in hexanes (25 mL) was reacted with Co ₂ (CO) ₈ (7.85 g) in hexanes (75 mL) over 30 min. , 23 mmol) was added to the solution. Moderate CO evolution was observed upon addition of each aliquot of 2,2-dimethyl-3-decyne solution. The resulting dark red-brown solution was stirred at room temperature for 4 hours. The volatiles were removed under vacuum at room temperature to give a dark red liquid with some suspended solids. A chromatography column (~3 diameter) was packed with 10 inches of neutral activated alumina using pure hexanes as the eluent. 5 mL of neat crude material was placed on the column and eluted using hexanes. The red-brown band moved quickly down the column with hexane. A small amount of dark material remained at the top of the column. The red-brown band was collected and evacuated to ~500 mTorr, yielding a dark red liquid.

¹ H NMR analysis of purified CCTHA sample (d ₈ -toluene): 2.66 (m), 1.61 (m), 1.23 (m), 1.17 (s), 0.86 (t).

Example 7

Synthesis of 2,2,6-trimethyl-3-heptyne (tert-butyl iso-butyl acetylene)

In a nitrogen glovebox, tert-butylacetylene (3,3-dimethyl-1-butyne) was prepared by placing tert-butylacetylene (5.0 g, 61 mmol) in a 250 mL Schrank flask with 100 mL of anhydrous THF. A solution was prepared. To a 60 mL addition funnel was added 24 mL of 2.5M n-butyllithium in hexanes (60 mmol). The flask and addition funnel were removed from the glovebox and assembled in a ventilation hood. The tert-butylacetylene solution was cooled to 0°C. The n-butyllithium solution was added dropwise to the tert-butylacetylene solution over 20 minutes while stirring. After the addition was complete, the pale yellow solution was warmed to room temperature over 2 hours with stirring. The obtained solution was cooled to 0°C. To a 60 mL addition funnel was added 1-iodo-2-methylpropane (9.9 g, 54 mmol) and 20 mL anhydrous THF. The cooled lithium tert-butylacetylide solution was added dropwise to this solution over 30 minutes while stirring. The color changed from pale yellow to colorless during addition. The solution was warmed to room temperature and stirred at room temperature for 2 days. GC-MS analysis showed almost complete conversion of the expected product. The solution was extracted with deionized water (2 × 100 mL). The water washes were extracted with 50 mL of hexanes. The organic fractions were combined and dried over anhydrous magnesium sulfate for 30 minutes. The solvent was removed by distillation at reduced pressure (~10 torr). The remaining colorless liquid was distilled under vacuum (~500 mTorr) into a receiver cooled to -78°C.

GC-MS analysis of the product indicated that the product was collected with greater than 98% purity.

Example 8

Synthesis of (2,2,6-trimethyl-3-heptyne) dicobalt hexacarbonyl (cobalt carbonyl tert-butyl iso-butyl acetylene-CCTIBA)

In a ventilated hood, a solution of 2,2,6-trimethyl-3-heptine (0.95 g, 6.6 mmol) in hexanes (15 mL) was incubated with Co ₂ (CO) ₈ (CO) in hexanes (45 mL) over 20 min. 2.1 g, 6.2 mmol) was added to the stirred solution. Moderate CO evolution was observed upon addition of 2,2,6-trimethyl-3-heptine solution. The obtained dark brown solution turned dark red over the course of 4 hours of stirring at room temperature. The volatiles were removed to give a dark brown solid. Addition of 5 mL of hexanes gave a dark reddish-brown liquid with some suspended solids. A chromatography column (~3 cm diameter) was packed with 8 inches of neutral activated alumina using pure hexanes as the eluent. The crude material was placed on the column and eluted using hexanes. The brown band quickly moved down the column with hexane. A small amount of dark purple material was retained in the top 1" of the column. The reddish-brown band was collected and evacuated to base vacuum (~500 mTorr) on a schwank line to yield a dark, viscous reddish-brown solid.

TGA analysis of CCTIBA by heating from room temperature to 400° C. under nitrogen flow shows 1.3% non-volatile residue.

¹ H NMR analysis of CCTIBA indicates that the product is of high purity (>99%). Chemical shifts (d ₈ -toluene): 2.55 (2H, d), 1.80 (1H, m), 1.15 (9H, s), 0.97 (6H, d).

¹³ C NMR analysis of CCTIBA obtained the following chemical shifts (d ₈ -toluene): 199.8, 111.6, 98.2, 41.1, 35.4, 31.0, 30.0, 22.2.

Example 9

Synthesis of 2,2-dimethyl-3-octyne (tert-butyl n-butyl acetylene)

In a nitrogen glovebox, tert-butylacetylene (3,3-dimethyl-1-butyne) was prepared by placing tert-butylacetylene (32.8 g, 0.4 mol) in a 1000 mL round bottom flask with 500 mL of anhydrous THF. A solution was prepared. To a 500 mL addition funnel was added 150 mL of 2.5M n-butyllithium in hexanes (0.375 mol). The flask and addition funnel were removed from the glovebox and assembled in the hood. The tert-butylacetylene solution was cooled to 0°C. The n-butyllithium solution was added dropwise to the tert-butylacetylene solution over 30 minutes while stirring. After the addition was complete, the colorless solution was allowed to warm to room temperature over 2 hours with stirring. To a 500 mL addition funnel was added 1-iodobutane (64.4 g, 0.35 mol) and 100 mL anhydrous THF. This solution was added to the lithium tert-butylacetylide solution over 30 minutes with stirring. The solution was stirred at room temperature for 3 days. GC-MS analysis of a small sample indicated complete conversion to product. The solution was extracted twice with 100 mL of deionized water. The water washes were extracted with 200 mL of hexane, and this extract was combined with the THF/hexane solution. The organic solution was dried over magnesium sulfate for 30 minutes. During this time, the colorless solution became bright yellow. The combined organic solutions were distilled under reduced pressure (~10 Torr) while maintaining the reboiler at 20°C, the condenser at 0°C, and the collection flask at -78°C. After removal of the solvent, another collection flask was equipped and the remaining volatiles were distilled off while maintaining the reboiler at 25°C, the condenser at 0°C, and the collection flask at -78°C. The pressure during the secondary distillation was ~2 torr. When all volatiles have been transferred, the collection flask is allowed to warm to room temperature. The colorless liquid was analyzed using GC-MS, which confirmed the presence of highly pure product (>99% purity, 42.2 g, 87% yield).

¹ H NMR analysis of 2,2-dimethyl-3-octyne gives the following chemical shifts: 2.03 (t, 2H); 1.33 (m, 4H); 1.19 (s, 9H); 0.80 (t, 3H).

Example 10

Synthesis of (2,2-dimethyl-3-octyne) dicobalt hexacarbonyl (cobalt carbonyl tert-butyl N-butyl acetylene (CCTNBA)

In a ventilated hood, a solution of 2,2-dimethyl-3-octyne (21.5 g, 0.15 mol) in hexanes (100 mL) was reacted with Co ₂ (CO) ₈ (47.5 g) in hexanes (700 mL) over 30 min. , 0.14 mol) was added to the solution. Upon addition of 2,2-dimethyl-3-octyne solution, visible CO evolution was observed. The obtained dark brown solution changed to dark reddish brown over the course of stirring at room temperature for 4 hours. The hexanes were removed using vacuum distillation while maintaining the reboiler at 25°C (condenser temperature -5°C; collection flask temperature -78°C), yielding a dark red liquid with thick solids. A chromatographic column (~3 inches in diameter) was packed with 8 inches of neutral activated alumina using pure hexanes as the eluent. The crude material was placed on the column and eluted using hexanes. The brown band quickly moved down the column with hexane. The dark purple material was retained in the top 2-3" of the column. The reddish-brown band was collected and evacuated on the Schrank line (~700 mTorr), yielding 40.0 g of dark red liquid.

¹ H NMR analysis of CCTNBA showed high purity (NMR assay 99.6%). Chemical shift (d ₈ -toluene): 2.66 (t, 2H), 1.60 (m, 2H), 1.29 (m, 2H), 1.17 (s, 9H), 0.86 (t, 3H).

Isothermal TGA data for (2,2-dimethyl-3-octyne) dicobalt hexacarbonyl (cobalt carbonyl tert-butyl N-butyl acetylene-CCTNBA) were determined at 75°C under nitrogen flow and are shown in Figure 2 It is shown in . The complex vaporized in ~200 min with a low non-volatile residue of 0.55%, confirming the good thermal stability of the CCTNBA precursor.

Figure 3 shows (3,3-dimethyl-1-butyne) dicobalt hexacarbonyl (CCTBA) and (2,2-dimethyl-3-octyne) dicobalt hexacarbonyl, as measured in a sealed SS316 DSC pan. A comparison of differential scanning calorimetry (DSC) data for Neil (CCTNBA) is shown.

Example 11

Deposition of Co films using CCTMA

In the deposition process, CCTMA was delivered to the reactor chamber by passing 50 sccm argon through a stainless steel vessel filled with CCTMA. The vessel temperature was varied between 30°C and 60°C to achieve sufficient vapor pressure of the CCTMA precursor. The substrate temperature varied from 125°C to 200°C. The reactor chamber pressure varied from 5 to 20 torr. Deposition tests were performed in the presence of 500 to 1000 sccm of hydrogen or argon flow. The deposition time varied from 20 seconds to 20 minutes to achieve Co films of different thicknesses (2 to 70 nm).

Figure 4 shows Co film resistivity versus film thickness for (3,3-dimethyl-1-butyne) dicobalt hexacarbonyl (CCTBA) and (4,4-dimethyl-2-pentyne dicobalt hexacarbonyl (CCTMA). Shown is an overlay of Co films were deposited using CCTMA and CCTBA at a substrate temperature of 150°C.

Figure 4 shows that as the temperature of the substrate increases to 175°C and 200°C, the resistivity of Co films deposited using CCTMA decreases to 150°C at the same film thickness and at a substrate temperature of 200°C. This indicates that the substrate temperature decreases to a point that is about 50% lower than for films deposited using CCTBA. In all cases, low resistivity films have a lower carbon content compared to films with high resistivity. Accordingly, the resistivity of the films described herein is a function of the residual carbon content of the deposited films.

Figure 4 shows that CCTMA provides Co films with much lower resistivity compared to cobalt films deposited from CCTBA.

Figure 5 shows transmission electron microscopy (TEM) images of cobalt films deposited on SiO ₂ using 4,4-dimethyl-2-pentyne dicobalt hexacarbonyl (CCTMA) as the Co film precursor.

Figure 5 shows that continuous films of Co metal can be formed on SiO ₂ with thicknesses as low as ∼2 nm.

Films were deposited from CCTMA and CCTBA and analyzed by X-ray photoelectron spectroscopy (XPS) to determine elemental concentrations throughout the metal films. Conditions for deposition of CCTMA were precursor delivery temperature = 50°C, wafer temperature = 200°C, deposition time = 10 minutes. Conditions for deposition of CCTBA were as follows: precursor delivery temperature = 35°C, wafer temperature = 175°C, deposition time = 3 minutes. The cobalt film deposited from CCTBA at 150°C contained a lower carbon content, 6.2 atomic %, but the carbon content in the film was still significantly higher compared to the carbon content in the cobalt film deposited from CCTMA at the same temperature (3.7 atomic %). .

Figure 6 shows the SiO ₂ phase using (3,3-dimethyl-1-butyne) dicobalt hexacarbonyl (CCTBA) and 4,4-dimethyl-2-pentyne dicobalt hexacarbonyl (CCTMA) as Co film precursors. XPS data for cobalt films deposited on is shown.

Figure 6 shows that Co films deposited on SiO ₂ using CCTMA as the Co film precursor had a significantly lower carbon level, 0.4 at %, than films deposited using CCTBA as the Co film precursor (11.1 at %). Instruct.

The conditions for Co film deposition using CCTMA were as follows: vessel temperature 50°C, wafer temperature 200°C, deposition time 10 minutes. The conditions for Co film deposition using CCTBA were as follows: vessel temperature 35°C, wafer temperature 175°C, deposition time 3 minutes.

Example 12

Deposition of low resistivity Co films using CCTNBA

In the deposition process, CCTNBA was delivered to the reactor chamber by passing 50 sccm argon through stainless steel vessels filled with CCTNBA. Process conditions were as follows: vessel temperature 50°C, hydrogen flow 50 sccm, pressure 10 torr. The substrate temperature ranges from 150 to 200°C. The substrate is SiO ₂ .

Table IV shows the dependence of film thickness on deposition time and substrate temperature.

Table IV

The data in Table IV indicates that higher substrate temperatures result in thicker Co films using CCTNBA as the Co film precursor.

Example 13

Preparation of CCTMA solution

Solutions of CCTMA in hexane were prepared by dissolving CCTMA in hexane while stirring using a magnetic stir bar. A solution of 70% by weight CCTMA in hexane was prepared by stirring the solid in hexane at 20° C. for 10 minutes.

Example 14

Preparation of CCTPA solution

Solutions of CCTPA in hexane were prepared by dissolving CCTPA in hexane while stirring using a magnetic stir bar. A solution of greater than 50% by weight CCTPA in hexane was prepared by stirring the solid in hexane at 20° C. for 5 minutes.

Example 15

Selective deposition of Co films using CCTNBA at 125°C

During the deposition process, CCTNBA was delivered to the reactor chamber by passing 50 sccm argon through a stainless steel vessel filled with CCTNBA. Process conditions were vessel temperature of 50°C, hydrogen flow of 500 sccm, chamber pressure of 10 torr, and deposition time of 1 minute. The substrate temperature was 125°C. The substrate was copper metal or thermal SiO ₂ .

Table V shows deposition results for Co film deposition on copper and SiO ₂ using CCTNBA as the cobalt precursor material. Selectivity is defined as the ratio of the film thickness of cobalt on copper to the film thickness of cobalt on SiO ₂ . Cobalt film thickness was measured using XRF. Wafers were pre-cleaned with 100, 200 or 500 W hydrogen plasma at 125°C for 1 and 3 minutes.

Table V

Over a set of five experiments, the average selectivity of the film thickness of cobalt on copper relative to the film thickness of cobalt on SiO ₂ was 14.5.

Example 16

Selective deposition of Co films using CCTNBA at 150°C

During the deposition process, CCTNBA was delivered to the reactor chamber by passing 50 sccm argon through a stainless steel vessel filled with CCTNBA. Process conditions were vessel temperature of 50°C, hydrogen flow of 500 sccm, chamber pressure of 10 torr, and deposition time of 1 minute. The substrate temperature was 150°C. The substrate was copper metal or thermal SiO ₂ .

Table VI shows deposition results for Co film deposition on copper and SiO ₂ using CCTNBA as the cobalt precursor material. Selectivity is defined as the ratio of the film thickness of cobalt on copper to the film thickness of cobalt on SiO ₂ . Cobalt film thickness was measured using XRF.

Table VI

Over a set of five experiments, the average selectivity of the film thickness of cobalt on copper relative to the film thickness of cobalt on SiO ₂ is 6.2, which is selected at higher deposition temperatures due to the greater amount of cobalt deposited on the dielectric substrate. The degree is low and indicates that the cobalt deposited on the metal does not change.

Example 17

Annealing of cobalt films formed from CCTNBA

During the deposition process, CCTNBA was delivered to the reactor chamber by passing 50 sccm argon through a stainless steel vessel filled with CCTNBA. Process conditions were vessel temperature of 60°C, hydrogen flow of 500 sccm, chamber pressure of 10 torr, and deposition time of 100 minutes. The SiO ₂ substrate temperature was 125°C.

In experiments where substrate plasma pretreatment was performed, the pretreatment conditions were 500 sccm of hydrogen flow, 200 W of plasma power, 3 minutes of pretreatment time, and 1 torr of hydrogen pressure.

The conditions for post-deposition annealing treatment were nitrogen flow of 450 sccm, hydrogen flow of 50 sccm, temperature of 400°C, chamber pressure of 50 torr, and annealing time of 30 minutes.

Table VII shows the effect of annealing on the resistivity of the deposited cobalt film. The annealing process lowers the resistivity of the cobalt metal film.

Table VII

Although the principles of the invention have been described above in connection with preferred embodiments, it will be clearly understood that such description is by way of example only and is not intended to limit the scope of the invention.

Claims (20)

A method for selectively depositing cobalt on a substrate in a reactor, comprising:
providing a substrate to the reactor, the substrate comprising at least one patterned dielectric layer and at least one patterned conductive metal layer;
performing pre-treatment to remove contaminants from the surface of the substrate, including at least the surface of at least one patterned conductive metal layer;
providing a Co precursor to the reactor;
contacting the substrate with a Co precursor; and
Forming a Co-containing film on the substrate,
Co precursors include (2,2,6-trimethyl-3-heptyne) dicobalt hexacarbonyl (CCTIBA); (2,2-dimethyl-3-octyne) dicobalt hexacarbonyl (CCTNBA); (2,2-dimethyl-3-decyne) dicobalt hexacarbonyl (CCTHA); and (2,2-dimethyl-3-heptyne) dicobalt hexacarbonyl (CCTPA);
The Co-containing film has at least one patterned conductive layer, with a ratio of the thickness of the cobalt-containing film formed on the at least one patterned conductive metal layer to the thickness of the cobalt-containing film formed on the at least one patterned dielectric layer greater than 1. A method of selectively forming on a metal layer. delete delete 2. The method of claim 1, wherein the disubstituted alkyne dicobalt carbonyl hexacarbonyl compound is a liquid compound at temperatures below 30°C. 5. The method of claim 4, wherein the disubstituted alkyne dicobalt carbonyl hexacarbonyl compound is (2,2-dimethyl-3-octyne) dicobalt hexacarbonyl (CCTNBA). The method of claim 1, wherein the Co-containing film is selected from the group consisting of a cobalt film, a cobalt oxide film, a cobalt silicide film, a cobalt nitride film, and combinations thereof, and the Co-containing film is selected from the group consisting of thermal CVD, thermal ALD, and plasma-enhanced ALD ( By a method selected from the group consisting of plasma enhanced atomic layer deposition (PEALD), plasma enhanced chemical vapor deposition (PECVD), and plasma enhanced cyclic chemical vapor deposition (PECCVD). Deposited method. The method of claim 1 further comprising annealing the Co-containing film on the substrate. 2. The method of claim 1, wherein at least one patterned conductive metal layer comprises copper; At least one patterned dielectric layer is made of silicon dioxide, fluorosilicate glass (FSG), organosilicate glass (OSG), carbon doped oxide (CDO), and porous low-K. A method comprising at least one selected from substances. 2. The method of claim 1, wherein the cobalt-containing film contains less than 2.5 atomic percent carbon. 9. The method of claim 8, wherein the cobalt-containing film contains less than 0.5 atomic percent carbon. The method of claim 1, wherein pre-treating includes exposing the substrate to a hydrogen plasma. The method of claim 1, wherein the ratio of the thickness of the cobalt-containing film is at least 5. 2. The method of claim 1, wherein the ratio of the thickness of the cobalt-containing film is at least 10. (1) at least one patterned dielectric layer formed with a Co-containing film on the surface of the substrate; and
(2) a substrate containing at least one patterned conductive metal layer with a Co-containing film formed on the surface of the substrate,
A semiconductor device, wherein the Co-containing film on the substrate is deposited according to claim 1. 15. The semiconductor device of claim 14, wherein the ratio of the thickness of the cobalt-containing film is 5 or more. 15. The semiconductor device of claim 14, wherein the ratio of the thickness of the cobalt-containing film is 10 or more. A method of depositing cobalt on a substrate in a reactor, comprising:
providing a substrate to the reactor;
providing a Co precursor to the reactor;
contacting the substrate with a Co precursor;
forming a Co-containing film on a substrate;
Annealing the Co-containing film; and
arbitrarily,
performing pre-treatment to remove contaminants from the surface of the substrate prior to providing a Co precursor to the reactor,
Co precursors include (2,2,6-trimethyl-3-heptyne) dicobalt hexacarbonyl (CCTIBA); (2,2-dimethyl-3-octyne) dicobalt hexacarbonyl (CCTNBA); (2,2-dimethyl-3-decyne) dicobalt hexacarbonyl (CCTHA); and (2,2-dimethyl-3-heptyne) dicobalt hexacarbonyl (CCTPA);
The substrate is selected from the group consisting of metal, metal oxide, metal nitride, silicon, silicon oxide, silicon nitride, TaN, and combinations thereof;
The Co-containing film is selected from the group consisting of a cobalt film, a cobalt oxide film, a cobalt silicide film, a cobalt nitride film, and combinations thereof. 18. The method of claim 17, wherein annealing reduces the resistivity of the cobalt-containing film. 18. The method of claim 17, wherein the disubstituted alkyne dicobalt carbonyl hexacarbonyl compound is a liquid compound at temperatures below 30°C. 18. The method of claim 17, wherein the disubstituted alkyne dicobalt carbonyl hexacarbonyl compound is (2,2-dimethyl-3-octyne) dicobalt hexacarbonyl (CCTNBA).

Images