JPH11269656A - Production of thin film forming composition and thin film using the composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high purity compsn. by adding a metal salt, metal chelate or metal alkoxide to a soln. prepared by diluting an alkyl amine with an org. solvent such as a hydrocarbon. SOLUTION: A soln. prepared by diluting an alkylamine with an org. solvent such as an aromatic hydrocarbon or other hydrocarbons is brought into contact with an aq. soln. of salts of metals in groups III to V, group VIII, group VIa, group VIIa, group Ib or group IIb, the pH of which is previously controlled, so as to extract the metal salts in the org. solvent phase while the water phase is separated and removed to obtain a soln. containing a metal alkylamine complex. Or, further the org. solvent used for extraction is removed by vaporization and distillation, and an org. solvent for substitution such as hydrocarbons, alcohols, esters, β-diketoesters, ethers, β-diketones, glycols or mixtures of these is added to the obtd. soln. By using the thin film forming compsn. thus prepared, a metal or metal oxide thin film is formed on a substrate by a coating and pyrolyzing method or a CVD method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a composition for forming a thin film of a metal salt to which an alkylamine is coordinated for application to a high-purity metal or a metal oxide thin film for an electronic material, and using the same. Related to thin films.

[0002]

2. Description of the Related Art Generally, oxide thin film materials used as electronic materials are required to have high purity. Almost all metals used for electronic materials contain alkali metals and impurities specific to each metal. For this reason, expensive and high-purity raw materials must be selected, and time-consuming distillation purification, acid, alkali, etc. Purity is raised by making full use of complex metal separation and purification technology using such methods.

[0003] In order to obtain a thin film of a metal oxide by a coating thermal decomposition method, a metal carboxylate, a metal acetylacetonate,
Compounds soluble in organic solvents such as metal alkoxides have been synthesized or commercial products have been dissolved in various solvents before use.

[0004] Carboxylic acids, β-diketones, alcohols, etc., which react with metals, do not form compounds with any metals. Among them, compounds such as transition metals and platinum group metals are difficult to form. No thin film forming composition soluble in an organic solvent has been found, and there are very few examples of obtaining these transition metal and platinum group thin films by a coating pyrolysis method.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to overcome the above-mentioned various drawbacks, and has as its object to provide a novel method for producing a high-purity thin film forming composition and a thin film using the same. Aim.

[0006]

SUMMARY OF THE INVENTION The present invention is directed to a method of preparing a solution prepared by diluting an alkylamine with an organic solvent such as an aromatic hydrocarbon or another hydrocarbon and adjusting the pH of the solution to a pH value of III-V.
Group, VIII, VIa, VIIa, Ib, II
The metal salt is extracted into an organic solvent layer by contacting with an aqueous solution of a metal salt of group b or the like, and the aqueous layer is separated and removed to obtain an organic solvent solution containing a metal alkylamine complex, or further used during extraction. The organic solvent is distilled off and the solution contains hydrocarbons, alcohols, esters, β-
This is a process for producing a composition for forming a thin film, comprising adding an organic solvent for substitution, such as diketoesters, ethers, β-diketones, and glycols, or a mixture thereof.

Further, the present invention provides a method for forming a thin film, comprising adding a metal salt, a metal chelate or a metal alkoxide to a solution obtained by diluting an alkylamine with an organic solvent such as an aromatic hydrocarbon or another hydrocarbon. A method for producing a composition.

Further, the present invention is a thin film formed by applying a metal or a metal oxide using the composition for forming a thin film on a substrate by a coating thermal decomposition method or a CVD method.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The alkylamine described in the claims means a monoalkylamine such as mono-n-octylamine and mono-2ethylhexylamine, and a dialkyl such as di-n-octylamine and di-2ethylhexylamine. Amines, tri-n-octylamine, and trialkylamines such as tri-2ethylhexylamine.

Organic solvents such as aromatic hydrocarbons and other hydrocarbons include benzene, toluene, xylene, heptane, hexane, octane, cyclohexane,
Hydrocarbons such as mineral terpenes and kerosene.

By appropriately combining these alkylamines and the above-mentioned organic solvents, it is possible to prepare an extraction solution having high extraction efficiency. If the solvent is not properly selected depending on the metal, the aqueous layer, extraction layer,
It is difficult to separate the solvent layer into the three components and extract the required extraction layer.

The metal salts described in the claims are sulfates, nitrates, halides, carboxylates, sulfamates and the like, and the metal chelates are metal acetylacetonate, metal pivaloyl methanate. , Metal phthalocyanine, etc., and the metals therein are Y, Ti, Zr,
V, Nb, Ta, Mn, Re, Fe, Co, Ni. R
u, Os, Rh, Ir, Pd, Pt, Zn, Cd, A
1, Ga, In, Ag, Bi, Sn, Sb, Ce, P
r, Nd, Pm, Sm, Eu, etc., but any metal that forms a complex with the alkylamine may be used.

The substitution organic solvent includes hydrocarbons such as benzene, toluene, xylene, heptane, hexane, cyclohexane, octane, mineral terpene and kerosene, methanol, ethanol, isopropyl alcohol, n-propyl alcohol, isobutanol, n-
Alcohols such as butanol, hexanol, n-octanol, isooctanol and benzyl alcohol; esters such as ethyl acetate, butyl acetate and isoamyl acetate; keto esters such as methyl acetoacetate and ethyl acetoacetate; ethylene glycol monomethyl ether; ethylene glycol Glycol ethers such as monoethyl ether and ethylene glycol monobutyl ether; glycols such as ethylene glycol, propylene glycol and glycerin; and acetylacetone.

Next, the manufacturing method of claim 1 will be described. Mix the alkylamine solution diluted with the organic solvent with the water-soluble metal salt, and use a mineral acid such as hydrochloric acid, sulfuric acid, or nitric acid to extract the metal salt into the alkylamine solvent layer. Adjust the pH in the layer. The aqueous layer and the organic solvent layer are mixed and stirred while being well heated. It is preferable to heat to 30 to 60 ° C. in order to clarify the separation between the aqueous layer and the organic solvent layer.

The metal salts extracted in the solvent layer are separated into an aqueous layer and a solvent layer using a separation tank. At this time, the alkali metal remains in the aqueous layer because it is not extracted by the alkylamine, but is slightly dissolved in the solvent layer. It is desirable to add a water washing step in order to remove the alkali metal, and the water washing can be efficiently reduced by repeating the water washing two to three times by adding an equal amount of water to the solvent.

The metal alkylamine complex extracted in the solvent layer may be used as a thin film forming solution as it is in the extracted solvent solution. However, depending on the type of the metal, the coating film may be repelled, clouded, or cracked during the formation of the thin film. Sometimes. In such a case, it is necessary to select a solvent.
The organic solvent used at the time of extraction is distilled off by evaporation and replaced with an organic solvent suitable for the metal.

Next, the manufacturing method of claim 2 will be described. Metal salts, metal chelates, metal alkoxides, and the like, which are soluble in an organic solvent, can be dissolved in an organic solvent and added directly to an alkylamine to be used as a thin film forming solution. Compounds soluble in organic solvents include metal salts of 2-ethylhexylic acid, metal acetylacetonate complexes, metal phthalocyanine complexes, metal alkoxides, and the like. A polynuclear complex in which a carboxylate ion, acetylacetone, phthalocyanine, halogen, hydroxyl group, etc., expected to be formed by directly adding a metal compound soluble in an organic solvent to an alkylamine, is coordinated with the metal ion in solution together with the alkylamine. It may be.

The composition for forming a thin film produced in this manner is applied on a glass or silicon substrate to a thickness of 1500 to 200.
The coating film spin-coated at 0 revolution is dried at 120 ° C. for several minutes or directly in an electric furnace at 550-650 ° C. for 10-2.
By baking for 0 minutes, a high-purity metal oxide thin film can be obtained. By firing in a hydrogen stream, a high-purity metal thin film can be obtained. Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

[0019]

Example 1 3.8 g of cobalt chloride was dissolved in 50 g of water, and 24.6 g of 35% hydrochloric acid was added thereto. A solution in which 15.8 g of trioctylamine was mixed with 40 g of xylene was added to the above solution, and the mixture was heated to 60 ° C. with stirring.
The aqueous layer and the solvent layer were separated, only the solvent layer was taken out, and the solvent xylene was distilled off to obtain a thin film forming composition. As a result of the analysis, this blue trioctylamine cobalt complex
Was 0.1 ppm or less. In addition, 1200p
The pm nickel remained in the aqueous layer and did not enter the solution of the trioctylamine cobalt complex. This solution is applied onto a silicon substrate by spin coating at 500 rpm.
m for 5 seconds, 2000 rpm for 30 seconds, 650
It baked for 20 minutes in the electric furnace of ° C. A transparent thin film of high-purity cobalt oxide was obtained on a silicon substrate. Further, firing was performed at 550 ° C. for 2 hours in a hydrogen gas atmosphere to obtain a high-purity metal cobalt thin film.

[0020]

Example 2 4 g of copper chloride was dissolved in 50 g of water, and 24.6 g of 35% hydrochloric acid was added thereto. A solution obtained by adding 15.8 g of trioctylamine to a mixed solution of 20 g of kerosene and 20 g of xylene is added to the above solution, and the solution is stirred for 60 hours.
%. The aqueous layer and the solvent layer were separated, only the solvent layer was taken out, and the solvent kerosene and xylene were distilled off to obtain a trioctylamine copper complex thin film-forming composition. As a result of analysis, Na in the yellow trioctylamine copper complex solution was analyzed,
It was 0.1 ppm or less. This solution is spin-coated on a silicon substrate at 500 rpm for 5 seconds and 2,000 rpm.
m for 30 seconds and baked in an electric furnace at 650 ° C. for 20 minutes. A thin film of copper oxide was obtained on a silicon substrate.

[0021]

Example 3 7.7 g of iridic acid chloride was dissolved in 100 g of water, and 10.6 g of trioctylamine and 150 g of xylene were added thereto, and the mixture was heated to 60 ° C. with stirring.
The aqueous and solvent layers were separated. The solvent layer was taken out and xylene was distilled off to obtain a brown trioctylamine iridium complex thin film-forming composition. The result of analysis of this solution by ICP emission analysis was 99.999% purity. This solution is spin-coated on a silicon substrate at 500 rpm.
For 5 seconds and 2000 rpm for 30 seconds, 550 ° C
For 20 minutes in an electric furnace. A golden shiny iridium oxide thin film was obtained on a silicon substrate. The resistivity of this thin film is 2.7 × 10 ⁻⁴ Ω · cm, suggesting that it can be used as an electrode material.

[0022]

Example 4 5.1 g of chloroplatinic acid was dissolved in 100 g of water, and 7 g of trioctylamine and 100 g of xylene were dissolved therein.
g of the mixed solution, and the mixture was heated to 60 ° C. with stirring, the aqueous layer and the solvent layer were separated, the solvent layer was taken out, xylene was distilled off, and a brown trioctylamine platinum complex thin film-forming composition was formed. I got This solution was coated on a silicon substrate by spin coating at 500 rpm for 5 seconds and 2000 rpm for 30 seconds, and baked in an electric furnace at 550 ° C. for 20 minutes to obtain a platinum oxide thin film having a metallic luster.

[0023]

Example 5 1.5 g of ruthenium chloride was dissolved in 200 g of water, and 60 g of hydrochloric acid was added. A mixed solution of 200 g of xylene and 22.2 g of mono-2-ethylhexylamine was added to the solution, and the mixture was heated to 60 ° C. with stirring to separate an aqueous layer and a solvent layer. The solvent layer was taken out and xylene was distilled off to obtain a brown mono-2ethylhexylamine ruthenium complex thin film-forming composition. This solution is spin-coated on a silicon substrate at 500 rpm for 5 seconds and 2000 rpm.
pm for 30 seconds and baked at 650 ° C for 20 minutes to obtain a golden shiny ruthenium oxide thin film.

[0024]

Example 6 A thin film of brown di-2ethylhexylamine ruthenium complex was formed in the same manner as in Example 5, except that mono-2ethylhexylamine in Example 5 was replaced with 27.6 g of di-2ethylhexylamine. A composition for use was obtained. This solution was spin-coated and fired on a silicon substrate in the same manner as in Example 5 to obtain a golden shiny ruthenium oxide thin film.

[0025]

Example 7 3 g of ruthenium chloride was dissolved in 200 g of water, and 80 g of hydrochloric acid was added. 200 g of xylene in the solution
And a mixed solution of 12.1 g of tri-n-octylamine were added, and the mixture was heated to 60 ° C. while stirring, and repeatedly washed with 200 g of water three times while separating an aqueous layer and a solvent layer. Thereafter, the solvent layer was taken out, and xylene was distilled off.
0 g was added to obtain a brown tri-n-octylamine ruthenium complex thin film-forming composition. This solution was spin-coated on a silicon substrate at 500 rpm for 5 seconds for 2000 seconds.
It was coated at rpm for 30 seconds and baked at 650 ° C. for 20 minutes to obtain a golden glossy ruthenium oxide thin film. The resistivity of the thin film was measured to be 1.9 × 10 ⁻⁴ Ω · c.
m. This suggests that this thin film can be used as a thin film material for electrodes.

[0026]

Example 8 The same operation as in Example 7 was carried out except that ethanol in Example 7 was replaced with 100 g of 2-ethoxyethanol. The resistivity of the thin film is 2.4 × 10 ⁻³ Ω
Cm.

[0027]

Example 9 Instead of ethanol in Example 7, 50 g of isooctyl alcohol and 50 g of 2-ethoxyethanol were used.
The procedure was performed in the same manner as in Example 7 except that the mixed solution was replaced with The resistivity of the thin film was 1.8 × 10 ⁻⁴ Ωcm.

[0028]

According to the present invention, a platinum group compound which is difficult to produce a compound which is soluble in an organic solvent can be easily formed into a solution by the method of the present invention. Further, a high-purity metal salt extraction solution from which impurity metals, particularly alkali metals disliked by electronic materials, are removed can be easily obtained. Further, by using the composition for forming a thin film according to the present invention, a thin film having high purity and good physical properties can be obtained.

Claims (3)

[Claims] 1. A solution obtained by diluting an alkylamine with an organic solvent such as an aromatic hydrocarbon or another hydrocarbon, and a pH-adjusted group of III-V, VIII, or VIa.
Contacting with an aqueous solution of a metal salt of Group III, Group VIIa, Group Ib, Group IIb, etc. to extract the metal salt into an organic solvent layer, and separating and removing the aqueous layer to obtain an organic solvent solution containing a metal alkylamine complex Or, furthermore, the organic solvent used at the time of extraction is distilled off by evaporation, and the solution contains hydrocarbons,
A method for producing a composition for forming a thin film, comprising adding a replacement organic solvent such as alcohols, esters, β-diketoesters, ethers, β-diketones, and glycols, or a mixture thereof. 2. A composition for forming a thin film, comprising adding a metal salt, a metal chelate or a metal alkoxide to a solution obtained by diluting an alkylamine with an organic solvent such as an aromatic hydrocarbon or another hydrocarbon. Law. 3. A thin film formed by applying a metal or a metal oxide on a substrate by using the solution according to claim 1 or 2 by a coating thermal decomposition method or a CVD method.