JP2002339076A - Method for forming metallic copper thin film and composition for forming copper thin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method by which wiring and electrodes usable for many electronic devices can easily and inexpensively be formed and a composition obtained by the method. SOLUTION: A solution of the composition for forming a metallic copper thin film containing at least one kind selected from a compound expressed by the following formula (1) of [R<1> COO]2 Cu (1) (wherein, R<1> denotes a 4 to 12C alkyl group) and a compound expressed by the following formula (2) of [R<2> -COCH=C(O)-R<3> ]2 Cu (2) (wherein, R<2> and R<3> are the same or different, and are a 1 to 12C alkyl group) and a solvent are applied, and a heat and/or light treatment is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a composition for forming a metal copper thin film, a metal copper thin film, and a method for forming the same. More specifically, a composition for forming a metal copper thin film which can be suitably used for forming wiring of an electronic device, a method of forming a copper thin film using the composition, and a copper thin film, a copper wiring and / or a copper thin film formed thereby Electrodes.

[0002]

2. Description of the Related Art Copper and aluminum are used as wiring materials used in many electronic devices such as solar cells, semiconductor devices, and electronic display devices.
The aluminum film is formed by sputtering, vacuum evaporation,
In general, the aluminum film is formed by a vacuum process such as a CVD method, and the aluminum film is formed into an aluminum pattern by a photo etching method using a resist. When copper is used for wiring, a copper pattern is generally formed by a method such as plating after forming a resist pattern on a substrate. Since these methods require a large-scale vacuum deposition apparatus and a resist pattern forming apparatus, they are disadvantageous not only in energy consumption but also difficult to form aluminum and copper wiring uniformly on a large-area substrate. As a result, the yield was low and this contributed to high costs.

On the other hand, in recent years, a paste in which copper or aluminum fine particles are dispersed in a binder has been developed, and the paste is subjected to pattern printing by a screen printing method or the like.
A method of forming an aluminum or copper pattern by firing is reported. This method is a method of directly patterning by printing from an aluminum paste or a copper paste, so it is inexpensive, but the obtained aluminum or copper contains impurities, so that it is difficult to obtain a low-resistance one. In addition, the formation of a fine pattern was technically difficult.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for easily and inexpensively forming wirings and electrodes which can be suitably used for many electronic devices, and a method for forming the same. It is an object of the present invention to provide a composition for forming a thin film, a method for forming a copper thin film using the composition, a copper thin film formed by the method, and a copper wiring and / or electrode made of the film.

[0005]

According to the present invention, the object is firstly achieved by the following formula (1) [R ¹ COO] ₂ Cu. . . (1) (where R ¹ represents an alkyl group having 4 to 12 carbon atoms) and a compound represented by the following formula (2) [R ² —COCH ＝ C (O) —R ³ ] ₂ Cu. . . (2) wherein R ² and R ³ are the same or different and are an alkyl group having 1 to 12 carbon atoms, and contain a solvent and at least one compound selected from the group consisting of compounds represented by the formula: The present invention is achieved by a composition for forming a metal copper thin film.

According to the present invention, the above object is secondly achieved by a film containing the above compound. According to the present invention, thirdly, the object is to provide, on a substrate surface, the following formula (1) [R ¹ COO] ₂ Cu. . . (1) (where R ¹ represents an alkyl group having 4 to 12 carbon atoms) and a compound represented by the following formula (2) [R ² —COCH ＝ C (O) —R ³ ] ₂ Cu. . . (2) (where R ² and R ³ are the same or different and are an alkyl group having 1 to 12 carbon atoms) A solution containing at least one compound selected from the group consisting of compounds represented by the following formula: And then subjecting the coated film to heat and / or light treatment.

According to the present invention, fourthly, the above object is attained by a copper thin film formed by the method for forming a metal copper thin film of the present invention. According to the present invention, fifthly, the above objects are attained by a copper wiring or a copper electrode formed by the above method of the present invention. Hereinafter, the present invention will be described in more detail.

The compound used in the present invention has the following formula (1) [R ¹ COO] ₂ Cu. . . (1) (where R ¹ represents an alkyl group having 4 to 12 carbon atoms) and a compound represented by the following formula (2) [R ² —COCH ＝ C (O) —R ³ ] ₂ Cu. . . (2) wherein R ² and R ³ are the same or different and are an alkyl group having 1 to 12 carbon atoms, and are at least one compound selected from the group consisting of compounds represented by the formula:

The production method of the compound represented by the formula (1) or (2) used in the present invention is not particularly limited. For example, the compound represented by the formula (1) It is easily prepared by dissolving copper in the corresponding dilute acid [R ¹ COOH] and concentrating it. The production of the compound of the formula (2) used in the present invention can be carried out, for example, by using MM Jones
[J. Amer. Chem. Soc., 81, p3188 (1959)
And diketone compounds [R ² —COCH ₂ CO— corresponding to copper (II) nitrate hydrate and concentrated aqueous ammonia
R ³ ].

In the formula (1), specific examples of the alkyl group having 4 to 12 carbon atoms for R ¹ include butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, And a saturated alkyl group such as a dodecyl group. These alkyl groups may be linear, cyclic, or branched. Specific examples of the compound represented by the above formula (1) include copper (II) n-butanoate, copper (II)
Isobutanoate, copper (II) n-pentanoate, copper (II) n-hexanoate, (II) n-2,2-dimethyl-propanoate, copper (II) 2-ethylhexanoate, copper (II) n-heptanoate, Copper (II) n-octanoate, copper (II) n-nonanoate, copper (II) n-decanoate, copper (II) n-undecanoate, copper (II)
n-Dodecanoate and the like can be mentioned. These copper compounds can be used alone or in combination of two or more.

In the above formula (2), R ² and R ^{3 each} have 1 carbon atom.
Specific examples of the alkyl group of to 12 include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group and the like. Groups. These alkyl groups may be linear, cyclic, or branched. Further, these alkyl groups may have a substituent such as a halogen group such as fluorine and chlorine. R ² and R ³ may be the same or different. Specific examples of the compound represented by the above formula (2) include copper (I
I) acetylacetonate, copper (II) ethanoylacetonate, copper (II) propionoylacetonate, copper (I
I) butanoylacetonate, copper (II) bis (2,2,6,
6-tetramethyl-3,5-hexanedionate, copper (II)
Hexafluoroacetylacetonate and the like can be mentioned. These copper compounds can be used alone or in combination of two or more.

In the present invention, the compounds represented by the above formulas (1) and (2) are dissolved in a solvent and used as a coating solution. The solvent is not particularly limited as long as it dissolves the compound represented by the formula (1) and / or the compound represented by (2) and does not react with the solvent.
Methanol, ethanol, propanol, butanol,
Pentanol, hexanol, octanol, decanol, undecanol, dodecanol, hexadecanol, octadecanol, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl Ether, propylene glycol monoethyl ether,
Alcohols such as glycerol, glycerol monomethyl ether, glycerol dimethyl ether, glycerol monoethyl ether and glycerol diethyl ether; ketones such as acetone, methyl ethyl ketone, diethyl ketone, methyl propyl ketone, dibutyl ketone, diisobutyl ketone, cyclopentanone and cyclohexanone; -Pentane, cyclopentane, n-hexane, cyclohexane, n-heptane, cycloheptane, n-octane, cyclooctane, decane, cyclodecane, dicyclopentadiene hydride, benzene, toluene, xylene, durene, indene, tetrahydronaphthalene, deca Hydrocarbon solvents such as hydronaphthalene and squalane; diethyl ether, dipropyl ether, dibutyl ether, Ether solvents such as tylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol methyl ethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, tetrahydrofuran, tetrahydropyran, bis (2-methoxyethyl) ether, p-dioxane; And a halogen-based solvent such as methylene chloride and chloroform. These solvents can be used alone or in combination of two or more. Among these, it is preferable to use an alcohol-based solvent, a ketone-based solvent, or a mixed solvent thereof for the compound represented by the formula (1) in view of its solubility and stability of the solution. As the compound represented by the formula (2), it is preferable to use a hydrocarbon-based solvent or a mixed solvent of a hydrocarbon-based solvent and the above-mentioned halogen-based solvent in terms of its solubility and stability of the solution.

The concentration of the compound represented by the above formula (1) and / or (2) in the solution is preferably 1 to 50% by weight. It can be appropriately adjusted according to the desired thickness of the metal copper thin film.

The solution of the compound represented by the above formula (1) and / or (2) may contain, if necessary, aluminum oxide,
It can be used by being appropriately mixed with fine particles of a metal oxide such as zirconium oxide, titanium oxide and silicon oxide. In addition, to improve the wettability of the solution to the application target, improve the leveling of the applied film, and prevent the occurrence of bumping of the coating film and the occurrence of citron skin, etc., so that the desired function is not impaired. If necessary, a small amount of a surface tension modifier such as a fluorine-based, silicone-based or nonionic surfactant can be added. Examples of the nonionic surfactant that can be added include a fluorine-based surfactant having an alkyl fluoride group or a perfluoroalkyl group, and a polyetheralkyl-based surfactant having an oxyalkyl group. . Examples of the fluorine-based surfactant include C ₉ F ₁₉ CONHC ₁₂ H ₂₅ and C ₈ F
₁₇ SO ₂ NH— (C ₂ H ₄ O) ₆ H, C ₉ F ₁₇ O (Pluronic L-35) C ₉ F ₁₇ , C ₉ F ₁₇ O (Pluronic P-
84) C ₉ F ₁₇ , C ₉ F ₁₇ O (Tetronic-704)
(C ₉ F ₁₇ ) _{2 and the} like. (Here, Pluronic L-35: manufactured by Asahi Denka Kogyo KK, polyoxypropylene-polyoxyethylene block copolymer, average molecular weight 1,900; Pluronic P-84: manufactured by Asahi Denka Kogyo KK, polyoxy Propylene-polyoxyethylene block copolymer, average molecular weight 4,200; Tetronic-704: N, N, N ', N', manufactured by Asahi Denka Kogyo KK
-Tetrakis (polyoxypropylene-polyoxyethylene block copolymer), having an average molecular weight of 5,000). Specific examples of these fluorine-based surfactants include:
F-top EF301, EF303, EF352
(Manufactured by Shin-Akita Chemical Co., Ltd.), Mega Fac F171, F
173 (Dainippon Ink Co., Ltd.), Asahi Guard AG7
10 (manufactured by Asahi Glass Co., Ltd.), Florard FC-170C,
FC430 and FC431 (Sumitomo 3M Limited)
Manufactured), Surflon S-382, SC101, SC1
02, SC103, SC104, SC105, SC106 (manufactured by Asahi Glass Co., Ltd.), BM-1000, 1
100 (manufactured by B-M-Chemie), Schsego
-Fluor (manufactured by Schwegmann) and the like. Examples of the polyether alkyl-based surfactant include, for example, polyoxyethylene alkyl ether, polyoxyethylene allyl ether, polyoxyethylene alkyl phenol ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, oxyethylene oxy Propylene block polymers and the like can be mentioned. Specific examples of these polyether alkyl surfactants include Emulgen 105, 430, and 8
10, 920, Rheodol SP-40S, TW-L
120, Emanol 3199, 4110, Exel P
-40S, Bridge 30, 52, 72, 92, Alassell 20, Emazor 320, Tween 20, 6
0, Merge 45 (all manufactured by Kao Corporation), Noni Ball 55 (manufactured by Sanyo Chemical Industries, Ltd.) and the like.
Examples of nonionic surfactants other than those described above include polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and polyalkylene oxide block copolymers.
500 (manufactured by Sanyo Chemical Industries, Ltd.), SN-EX9228
(Manufactured by San Nopco Co., Ltd.) and Nonal 530 (manufactured by Toho Chemical Industry Co., Ltd.).

The thus obtained solution composition is applied on a support to form a coating film comprising the copper compound represented by the formula (1). The material, shape, etc. of the support are not particularly limited, but the material is preferably one that can withstand the heat treatment in the next step, and the support forming the coating film may be flat or non-planar with a step. There is no particular limitation. Specific examples of the material of these supports include glass, metal, plastic, and ceramics.
As the glass, for example, quartz glass, borosilicate glass, soda glass, and lead glass can be used. Examples of the metal include gold, silver, copper, nickel, silicon, aluminum, iron, and stainless steel, and examples of the plastic include polyimide and polyether sulfone. Further, the shape of these materials is not particularly limited, such as lump, pipe, plate, and film. In applying the above solution, the application method is not particularly limited. For example, it can be carried out by spin coating, dip coating, curtain coating, roll coating, spray coating, ink jet, printing, or the like. The application can be repeated once or multiple times. The preferred thickness of the coating film varies as appropriate depending on the coating method and the solid content concentration, but is preferably from 0.01 to 10 as the film thickness.
The thickness is preferably 0 μm, more preferably 0.05 to 10 μm.

In the present invention, a metal copper thin film is obtained by subjecting a coating film of a solution containing the compound represented by the above formula (1) and / or the compound represented by the formula (2) to heat and / or light treatment. Can be converted to For the heat treatment, the temperature is preferably set to 150 ° C. or higher,
More preferably, the temperature is set to 0 to 500 ° C. A heating time of about 30 seconds to 30 minutes is sufficient.

The heat treatment conditions are as follows: a coating film formed from a solution containing the compound represented by the above formula (1) and / or the compound represented by the formula (2) is heated to a temperature of 100 ° C. or more under oxygen or an oxygen atmosphere. Then, it is preferable to fire at a temperature of 150 ° C. or more in a reducing atmosphere such as hydrogen. When firing in a reducing atmosphere such as hydrogen without oxygen, hydrogen may be used as a mixed gas with, for example, nitrogen, helium, argon, or the like. Further, a coating film of a solution using the compound represented by the formula (1) and / or the compound represented by the formula (2) may be subjected to light treatment to form a copper thin film. Light sources used for light treatment include low or high pressure mercury lamps, deuterium lamps or argon,
In addition to discharge light of rare gases such as krypton and xenon, YAG
Laser, argon laser, carbon dioxide laser, Xe
F, XeCl, XeBr, KrF, KrCl, ArF,
An excimer laser such as ArCl can be used as a light source. These light sources are generally
A power output of 10 to 5000 W is used.
00 to 1000 W is sufficient. The wavelength of these light sources is not particularly limited, but is usually 170 nm to 600 nm. The use of laser light is particularly preferable in terms of the effect of modifying the aluminum film. The temperature during these light treatments is usually around room temperature. When irradiating light, irradiation may be performed through a mask in order to irradiate only a specific portion.

[0018]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples.

EXAMPLE 1 Copper (II) 2-ethylhexanoate 10 in a nitrogen atmosphere
g of isopropyl alcohol 45 g and cyclohexa
A solution dissolved in 90 g of a mixed solvent of 45 g of non-glass
Spin coating on the board at 1000 rpm, then
Immediately heat-treat in air at 100 ° C for 30 minutes to remove solvent
Was removed to form a dark brown film. This dark brown film
30 minutes at 200 ° C in a nitrogen atmosphere containing 3% hydrogen
For a period of time, the red copper-colored metallic light
A copper thin film having a swamp was formed. Copper film on this substrate
The thickness was measured by αstep (Tencor)
It was 80 nm. Also, the ESCA of this copper film was measured.
The results are shown in FIG. Cu _{2p3 / 2}Is detected at 933 eV
It was found to be metallic copper. The specific resistance of this copper film is
When measured by the daughter method, it was 5 μΩ · cm.

Example 2 Copper (II) 2-ethylhexanoate 10 in a nitrogen atmosphere
g of isopropanol 45 g and t-butanol 45
g of a mixed solvent dissolved in 90 g of a mixed solvent was placed on a glass substrate.
Spin coating was performed at 000 rpm, and immediately thereafter, heat treatment was performed in air at 100 ° C. for 30 minutes to remove the solvent, thereby forming a dark brown film. The dark brown film was further heated at 250 ° C. for 30 minutes in a nitrogen atmosphere containing 3% hydrogen to form a copper thin film having a copper-red metallic luster on a glass substrate. The thickness of the copper film on this substrate is αs
90n as measured by Tep (Tencor)
m. When the ESCA of this copper film was measured, a spectrum equivalent to the spectrum obtained in Example 1 was observed, and it was found that the copper film was a metal copper thin film. When the specific resistance of this copper thin film was measured by a four-terminal method, it was 8 μΩ · cm.
Met.

Example 3 A solution prepared by dissolving 10 g of copper (II) bis (2,2,6,6-tetramethyl-3,5-heptanedionate) in a mixed solvent of 45 g of benzene and 45 g of xylene in a nitrogen atmosphere in a nitrogen atmosphere. Was spin-coated on a glass substrate at 1000 rpm, and immediately thereafter, heat-treated in air at 100 ° C. to remove the solvent, thereby forming a dark brown film. This dark brown film was further treated at 400 ° C. in a nitrogen atmosphere containing 3% hydrogen for 3 hours.
By heating for 0 minute, a copper film having a copper-red metallic luster was formed on the glass substrate. When the film thickness of the copper film on this substrate was measured by αstep, it was 75 nm. It was confirmed by ESCA measurement that the copper film was metallic copper.
When the specific resistance of this copper film was measured by the four-terminal method,
Cm.

Example 4 (Tridecafluoro-1,1,2,2) was applied to the entire surface of a glass substrate.
-Tetrahydrooctyl) triethoxysilane surface-treated was irradiated with ultraviolet light of 172 nm through a mask for 15 minutes. The copper (II) 2-ethylhexanoate 10 used in Example 1 was placed on this substrate in a nitrogen atmosphere.
g in a mixed solvent of 90 g of a mixed solvent of 45 g of isopropyl alcohol and 45 g of cyclohexanone.
When spin coating was performed at m, a film was formed only on the UV-irradiated portion, and no film was formed on the UV-irradiated portion. The substrate on which this pattern was applied was subjected to a heat treatment at 100 ° C. for 30 minutes in air in the same manner as in Example 1 to remove the solvent.
A dark brown pattern film was formed. This was further heated at 200 ° C. for 30 minutes in a nitrogen atmosphere containing 3% hydrogen, whereby a copper film patterned on a glass substrate,
That is, a copper wiring was formed. The film thickness of the copper film part is αst
It was 80 nm when measured by ep.

Example 5 Copper (II) bis (2,2,6,6-tetramethyl-3,5-heptanedio) of Example 3 was used in place of the copper (II) 2-ethylhexanoate of Example 4. A patterned copper film, that is, a copper wiring, was formed on a glass substrate in the same manner as in Example 4 except for using a copper salt. The thickness of the copper film portion measured by α step was 70 nm.

COMPARATIVE EXAMPLE 1 Instead of the copper (II) 2-ethylhexanoate used in Example 1, copper (II) acetate 5% ethanol / water (50 /
50) The same treatment as in Example 1 was performed using the mixed solution, but a copper thin film could not be formed.

[0025]

As described in detail above, according to the present invention,
Unlike conventional methods of forming copper films by vacuum processes such as sputtering, vacuum evaporation, and CVD, and plating methods, a specific compound is formed by a solution coating method using a method such as a spin coating method or an inkjet method. Then, an industrial method for easily forming a copper thin film by heat and / or light treatment is provided. A low-cost, uniform and dense copper thin film is formed by heat-treating and / or irradiating a precursor film formed by a coating method instead of deposition from a gas phase as in the conventional CVD method. Can be.

[Brief description of the drawings]

FIG. 1 is an ESCA spectrum of a copper film obtained in Example 1.

Continued on front page F term (reference) 4K022 AA02 AA03 AA04 AA43 BA08 DA06 DA08 DB01 4M104 BB04 CC01 DD51 DD62 DD77 DD78 DD81 HH20 5F033 GG04 HH11 PP26 QQ01 QQ71 QQ73 QQ82 QQ83 WW03 XX34

Claims (7)

[Claims] 1. The following formula (1): [R ¹ COO] ₂ Cu. . . (1) (where R ¹ represents an alkyl group having 4 to 12 carbon atoms) and a compound represented by the following formula (2) [R ² —COCH ＝ C (O) —R ³ ] ₂ Cu. . . (2) wherein R ² and R ³ are the same or different and are an alkyl group having 1 to 12 carbon atoms, and contain a solvent and at least one compound selected from the group consisting of compounds represented by the formula: A composition for forming a metal copper thin film, comprising: 2. A film comprising the compound according to claim 1. 3. The method according to claim 1, wherein the following formula (1) [R ¹ COO] ₂ Cu. . . (1) (where R ¹ represents an alkyl group having 4 to 12 carbon atoms) and a compound represented by the following formula (2) [R ² —COCH ＝ C (O) —R ³ ] ₂ Cu. . . (2) (where R ² and R ³ are the same or different and are an alkyl group having 1 to 12 carbon atoms) A solution containing at least one compound selected from the group consisting of compounds represented by the following formula: A method for forming a metallic copper thin film, comprising forming a coating film of the above, and then subjecting the coating film to heat and / or light treatment. 4. The heat treatment is performed in an oxygen or air atmosphere.
The method according to claim 2, comprising firing at a temperature of 150C or higher after firing at a temperature of 150C or higher. 5. A copper thin film formed by the method according to claim 4. 6. The method according to claim 1, wherein the formed metal copper thin film is a copper wiring and / or
5. The method according to claim 3, wherein the method is a copper electrode. 7. A copper wiring or a copper electrode formed by the method according to claim 6.