JP4962714B2 - Method for forming silicon dioxide film and trench isolation and composition therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition for forming a silicon dioxide film high in purity and density. <P>SOLUTION: A composition for forming an oxidized silicon contains a silicide shown by a formula (1) (R<SP>1</SP><SB>3</SB>SiO<SB>0.5</SB>)<SB>k</SB>(R<SP>2</SP><SB>2</SB>SiO)<SB>m</SB>(R<SP>3</SP>SiO<SB>1.5</SB>)<SB>n</SB>and a carbonate composition shown by a formula (2), where in the formula (2): R<SP>4</SP>and R<SP>5</SP>are independent from each other, and show an straight-chained or branched alkyl group having a hydrogen atom and 1 to 20 carbon atoms, a monovalent aromatic hydro carbon group having 6 to 20 carbon atoms, or a monovalent halogenated aromatic hydro carbon group having 6 to 20 carbon atoms; and R<SP>6</SP>shows a substituted or unsubstituted organic group having 1 to 20 carbon atoms. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a high-purity silicon dioxide film and a method for forming trench isolation used for device isolation of a semiconductor device, and a composition therefor.

Trench isolation is a technique for separating elements of a semiconductor device formed by integrating a large number of elements at a high density. The trench isolation structure is mainly formed by digging a groove in a silicon substrate by dry etching, filling SiO ₂ therein, and finally flattening by chemical mechanical polishing (CMP). This trench isolation does not increase the isolation size due to a process such as a bird's beak compared to the isolation formed by the LOCOS method. Therefore, it is suitable for high integration of elements. The trench isolation having the above structure is usually formed by the method described in “First Semiconductor Process” (by Kazuo Maeda, Industrial Research Co., Ltd.). As a general method for forming trench isolation, first, for example, by chemical vapor deposition, a silicon dioxide (SiO ₂ ) film and a silicon nitride (Si ₃ N ₄ ) film as an oxidation mask are formed on the upper surface of a silicon substrate. Are laminated. Next, an etching mask having a trench pattern with a resist is formed on the upper surface of the silicon nitride film by ordinary photolithography, and the silicon nitride film and the silicon oxide film are formed by anisotropic etching such as reactive ion etching. A trench is formed in the silicon substrate in a penetrating state. Thereafter, a silicon oxide film is formed on the inner wall of the trench by, for example, thermal oxidation or chemical vapor deposition, and then silicon oxide is deposited on the inside of the trench and the upper surface of the silicon nitride film by, for example, chemical vapor deposition. Form a layer. Then, the buried portion is planarized by chemical mechanical polishing (CMP) to form trench isolation. However, in the trench isolation formed by the above-described forming method, even if an insulator made of silicon dioxide is formed inside the trench by a chemical vapor deposition method with relatively good coverage, the aspect ratio of the trench (trench depth) When the (/ trench width) is 1 or more, local voids are formed inside the formed silicon dioxide. For this reason, when the heat treatment process is performed thereafter, the generated voids expand and destroy the trench isolation. Therefore, a chemical vapor deposition method using a mixed gas of ozone and tetraethoxysilane (TEOS) as a reaction gas is employed as a method for forming a silicon dioxide deposition layer with less local void generation. However, even in this method, local voids are generated in the silicon oxide deposition layer formed in the trench having the aspect ratio of 2 or more. In addition, since the silicon dioxide deposited layer formed by this chemical vapor deposition method has a lower density than the silicon dioxide deposited layer formed by other chemical vapor deposition methods, the insulating layer made of high resistance silicon dioxide is used. The body is difficult to form. In addition, each of the above methods has a problem in terms of cost because an expensive vacuum system is required. Also, since the raw material is in a gaseous state, the production yield due to contamination of the device and generation of foreign matter is low. There is a problem to be done.

  In view of the above circumstances, an object of the present invention is to provide a method for forming a high-purity and high-density silicon dioxide film or trench isolation that does not contain an organic component, and a composition therefor.

  Another object of the present invention is to form a silicon dioxide film or trench isolation with a high yield and a high formation rate by a simple operation and apparatus, unlike a method using a vacuum system such as a CVD method or a sputtering method. It is an object of the present invention to provide a composition having excellent formation stability and storage stability therefor.

  Still other objects and advantages of the present invention will become apparent from the following description.

According to the present invention, the above objects and advantages of the present invention are as follows.
A silicon oxide-forming composition comprising a silicon compound represented by the following formula (1) and a carbamate compound represented by the following formula (2).
(R ¹ ₃ SiO _0.5 ) _k (R ² ₂ SiO) _m (R ³ SiO _1.5 ) _n (1)
(In formula (1), R ¹ , R ² and R ³ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, or a linear or branched alkyl group having 1 to 20 carbon atoms. A linear or branched alkyl halide group having 1 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, or a monovalent halogenated aromatic hydrocarbon group having 6 to 20 carbon atoms And the sum of k, m and n is 1.)

(In formula (2), R ⁴ and R ⁵ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms, or a monovalent aromatic having 6 to 20 carbon atoms. A hydrocarbon group or a monovalent halogenated aromatic hydrocarbon group having ⁶ to 20 carbon atoms, and R ⁶ represents a substituted or unsubstituted organic group having 1 to 20 carbon atoms.)
Achieved by:

According to the present invention, the above objects and advantages of the present invention are secondly,
This is achieved by a method for forming a silicon dioxide film, which comprises applying the composition for forming silicon oxide of the present invention to a substrate and heating and / or irradiating with light.

According to the present invention, the above objects and advantages of the present invention are thirdly,
A method for forming a trench isolation for electrically isolating a plurality of semiconductor elements formed on a silicon substrate, wherein the silicon oxide forming composition of the present invention is applied onto the substrate so as to fill the trench in the substrate. This is achieved by a method for forming trench isolation, which is characterized by forming a film and then heating and / or light irradiation.

  According to the composition for forming silicon oxide of the present invention, a trench for electrically separating a plurality of semiconductor elements on a silicon substrate can be filled with high-purity and high-density silicon dioxide.

  Hereinafter, the present invention will be described in detail.

The silicon compound used in the present invention is represented by the above formula (1). The structure can be a chain, ring, or cage structure.
In the above formula (1), R ¹ , R ² and R ³ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a linear or branched alkyl group having 1 to 20 carbon atoms, A linear or branched alkyl halide group having 1 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, or a monovalent halogenated aromatic hydrocarbon group having 6 to 20 carbon atoms. Show.
Examples of the linear or branched alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, a t-butyl group, and an adamantyl group.
Examples of the linear or branched alkyl halide group having 1 to 20 carbon atoms include halogenated products of the above alkyl groups having 1 to 20 carbon atoms. Halogen includes fluorine, chlorine or bromine.
Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include a phenyl group and a naphthyl group.
Examples of the monovalent halogenated aromatic hydrocarbon group having 6 to 20 carbon atoms include the halogen compounds of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms. Again, halogen includes fluorine, chlorine, and bromine.
The silicon compounds represented by the above formula (1) can be used alone or in combination of two or more.
The solvent-soluble silicon compound represented by the above formula (1) can be produced, for example, by condensing a silicon compound represented by the following formula (3) in an organic solvent under basic or neutral conditions. .

Here, x represents an integer of 4 to 100,
The condensation reaction can be performed in a temperature range of −50 ° C. to 200 ° C., and is preferably reacted at 0 ° C. to 100 ° C.
When this condensation reaction is carried out under basic conditions, a basic catalyst can be used. The base catalyst may be either an inorganic base or an organic base. Examples of the inorganic base include lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium carbonate, potassium carbonate and the like.

Examples of the organic base include linear, branched or cyclic monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine and cyclohexylamine;
Di-n-butylamine, di-n-pentylamine, di-n-hexylamine, di-n-heptylamine, di-n-octylamine, di-n-nonylamine, di-n-decylamine, cyclohexylmethylamine, Linear, branched or cyclic dialkylamines such as dicyclohexylamine; triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptyl Linear, branched or cyclic trialkylamines such as amine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, cyclohexyldimethylamine, dicyclohexylmethylamine, tricyclohexylamine;
Aromatic amines such as aniline, N-methylaniline, N, N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, 4-nitroaniline, diphenylamine, triphenylamine, naphthylamine;
Ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 4,4′-diaminobenzophenone, 4, 4'-diaminodiphenylamine, 2,2-bis (4-aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2- (4-aminophenyl) -2- ( 3-hydroxyphenyl) propane, 2- (4-aminophenyl) -2- (4-hydroxyphenyl) propane, 1,4-bis [1- (4-aminophenyl) -1-methylethyl] benzene, 1, Diamines such as 3-bis [1- (4-aminophenyl) -1-methylethyl] benzene;
Imidazole such as imidazole, benzimidazole, 4-methylimidazole, 4-methyl-2-phenylimidazole; pyridine, 2-methylpyridine, 4-methylpyridine, 2-ethylpyridine, 4-ethylpyridine, 2-phenylpyridine, 4 -Pyridine such as phenylpyridine, 2-methyl-4-phenylpyridine, nicotine, nicotinic acid, nicotinamide, quinoline, 4-hydroxyquinoline, 8-oxyquinoline, acridine; piperazine, 1- (2-hydroxyethyl) piperazine In addition to piperazines such as pyrazine, pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, morpholine, 4-methylmorpholine, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2.2] octane, etc. Other nitrogen It can be mentioned heterocyclic compounds.
These base catalysts can be used alone or in admixture of two or more.

  In the present invention, the organic solvent used at the time of condensation is not particularly limited as long as it does not react with the silicone resin component. For example, chlorinated solvents such as methylene chloride, chloroform, carbon tetrachloride; n-pentane, n-hexane, n-heptane, n-octane, decane, dicyclopentane, benzene, toluene, xylene, durene, indene, tetrahydronaphthalene , Hydrocarbon solvents such as decahydronaphthalene and squalane; diethyl ether, dipropyl ether, dibutyl ether, ethyl butyl ether, ethyl pentyl ether, ethyl hexyl ether, ethylene 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, bis (2-methoxyethyl) ether, - dioxane, ether solvents such as tetrahydrofuran; can be cited, and propylene carbonate, .gamma.-butyrolactone, N- methyl-2-pyrrolidone, dimethylformamide, polar solvents such as acetonitrile. Of these, chlorine-based solvents, ether-based solvents, and hydrocarbon-based solvents are preferable from the viewpoint of the stability of the solution.

In the above formula (1), the silicon compounds in which R ¹ , R ² and R ³ are other than hydrogen atoms are represented by R ¹ ₃ SiX, R ² SiX ₂ and R ³ SiX ₃ according to a method known per se. It can be produced by appropriately mixing and hydrolyzing and polycondensing the compounds.
In these formulas, X is a hydrolyzable group of a halogen atom or an alkoxy group.
By the condensation reaction, a silicone resin that is a silicon compound represented by the formula (1) can be produced.

The silicon compound represented by the above formula (1) is k + m + n = 1, preferably k is 0 to 0.2, m is 0.2 to 0.8, and n is 0.2 to 0.8. is there. When k is larger than 0.2, coating abnormality such as insufficient film thickness is likely to occur. When m is smaller than 0.2, the solubility of the silicon compound in the solvent is lowered and the storage stability of the composition is deteriorated. When m is larger than 0.8, the film formability is deteriorated. When n is less than 0.2, abnormal film formation tends to occur, and when n is greater than 0.8, the storage stability of the silicon compound solution is deteriorated. The molecular weight of the silicon compound is preferably 200 to 500,000, more preferably 1,000 to 100,000, and still more preferably 2,000 to 50,000. Such silicon compounds can be used alone or in admixture of two or more having different molecular weights and compositions.
The silicon compound represented by the above formula (3) can be synthesized by hydrolyzing dichlorosilane in an organic solvent. In the hydrolysis, a third component such as a catalyst may be added in addition to the organic solvent and water.

  The solvent used here is not particularly limited as long as it does not react with the silicone resin component. For example, chlorinated solvents such as methylene chloride, chloroform, carbon tetrachloride; n-pentane, n-hexane, n-heptane, n-octane, decane, dicyclopentane, benzene, toluene, xylene, durene, indene, tetrahydronaphthalene , Hydrocarbon solvents such as decahydronaphthalene and squalane; diethyl ether, dipropyl ether, dibutyl ether, ethyl butyl ether, ethyl pentyl ether, ethyl hexyl ether, ethylene 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, bis (2-methoxyethyl) ether, - dioxane, ether solvents such as tetrahydrofuran; can be cited, and propylene carbonate, .gamma.-butyrolactone, N- methyl-2-pyrrolidone, dimethylformamide, polar solvents such as acetonitrile. Of these, chlorine-based solvents, ether-based solvents, and hydrocarbon-based solvents are preferable from the viewpoint of the stability of the solution.

The amount of water for hydrolysis is preferably 0.5 mol% or more, more preferably 10 mol% or less, still more preferably 0.9 mol% or more, particularly preferably 1.5 mol%, based on dichlorosilane. It is less than mol%. If the amount of water added is 0.5 mol% or less, the unreacted chloro compound remains in the hydrolysis reaction. On the other hand, if the amount of water added is 10 mol% or more, the reaction rapidly proceeds and gelation may occur. The amount of water used in this reaction indicates all water that may be present in the reaction system, such as dichlorosilane, solvent, other additives, atmosphere, and apparatus, in addition to the water to be added.
This hydrolysis reaction is desirably performed at a temperature of −78 ° C. to 100 ° C., and particularly desirably within a range of −20 ° C. to 50 ° C.

The silicon compound represented by the above formula (3) is a stable compound at room temperature, but when handled at room temperature, it is preferably handled and stored in the solution state of the solvent shown above, and is handled in a solvent-free state. When storing, it is desirable to carry out at 0 ° C or less.
Further, the silicon compound represented by the above formula (3) can be purified by distillation, the degree of vacuum during distillation is desirably normal pressure (760 mmHg) or less, and the heating temperature during distillation is desirably 200 ° C. or less. It is also desirable to store the silicon compound represented by the above formula (3) obtained by the above in a solution state. By distillation, demetalization, dehalogenation and the like are possible. When this condition is not maintained, gelation proceeds and the target product may not be obtained.

The carbamate compound used in the present invention is represented by the above formula (2). In formula (2), R ⁴ and R ⁵ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon having 6 to 20 carbon atoms. Or a monovalent halogen aromatic hydrocarbon group having 6 to 20 carbon atoms.
Specific examples of these alkyl groups, aromatic hydrocarbon groups and halogenated aromatic hydrocarbon groups are the same as those described above for R ¹ , R ² and R ³ .
In formula (2), R ⁶ represents a substituted or unsubstituted organic group having 1 to 20 carbon atoms. Specific examples of R ⁶ include the alkyl groups, aromatic hydrocarbon groups, and halogenated aromatic hydrocarbon groups described above for R ¹ , R ^2, and R ^3. Among these, t-butyl group, t- Carbon bonded to carbonyloxy group such as amyl group, 1-methylcyclohexyl group, 1-adamantyl group, 1-methyl-1-phenylethyl group, 1,1-diphenylethyl group, triphenylmethyl group is tertiary. Carbon is preferred.

Among the carbamate compounds represented by the above formula (2), examples of the compound in which R ⁶ is a t-butyl group include Nt-butoxycarbonyldi-n-octylamine and Nt-butoxycarbonyldi-n-. Nonylamine, Nt-butoxycarbonyldi-n-decylamine, Nt-butoxycarbonyldicyclohexylamine, Nt-butoxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl-N-methyl-1-adamantylamine N, N-di-t-butoxycarbonyl-1-adamantylamine, N, N-di-t-butoxycarbonyl-N-methyl-1-adamantylamine, Nt-butoxycarbonyl-4,4′-diamino Diphenylmethane, N, N′-di-t-butoxycarbonylhexamethylenediamine, N, N N′N′-tetra-t-butoxycarbonylhexamethylenediamine, N, N′-di-t-butoxycarbonyl-1,7-diaminoheptane, N, N′-di-t-butoxycarbonyl-1,8- Diaminooctane, N, N′-di-t-butoxycarbonyl-1,9-diaminononane, N, N′-di-t-butoxycarbonyl-1,10-diaminodecane, N, N′-di-t-butoxy Carbonyl-1,12-diaminododecane,
N, N′-di-t-butoxycarbonyl-4,4′-diaminodiphenylmethane, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-methylbenzimidazole, Nt-butoxycarbonyl-2 -Nt-butoxycarbonyl group-containing amino compounds such as phenylbenzimidazole, formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, Examples thereof include benzamide, pyrrolidone, N-methylpyrrolidone and the like.
The carbamate compounds can be used alone or in combination of two or more.

In the composition of the present invention, the silicon compound represented by the above formula (1) and the carbamate compound represented by the above formula (2) are preferably 70 to 99.9% by weight, respectively, based on the total of both. Preferably it contains 75 to 99 wt% and preferably 0.1 to 30 wt%, more preferably 1 to 25 wt%.
When the carbamate compound represented by the above formula (2) is used in combination with the silicon compound represented by the above formula (1), it is stable in a solution and heated after film formation, so that Si— It is possible to increase the density of the silicon dioxide film by constructing O-Si bonds and increasing the degree of crosslinking.
In the composition of this invention, other components, such as a solvent, may exist as needed.
The above composition is used in the method for forming a silicon dioxide film and the method for forming a trench isolation of the present invention.

  The composition is formed by dissolving the silicon compound of the above formula (1) and the carbamate compound of the above formula (2) in a solvent. The solvent used here is not particularly limited as long as it does not react with these components. For example, hydrocarbon solvents such as n-pentane, n-hexane, n-heptane, n-octane, decane, dicyclopentane, benzene, toluene, xylene, durene, indene, tetrahydronaphthalene, decahydronaphthalene, squalane; diethyl Ether, dipropyl ether, dibutyl ether, ethyl butyl ether, ethyl pentyl ether, ethyl hexyl ether, ethylene 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, bis (2- Ether solvents such as methoxyethyl) ether, p-dioxane, tetrahydrofuran; And propylene carbonate, .gamma.-butyrolactone, N- methyl-2-pyrrolidone, dimethyl formamide, may be mentioned polar solvents such as acetonitrile. Of these, ether solvents and hydrocarbon solvents are preferred in view of the stability of the solution. These solvents can be used alone or as a mixture of two or more. When the above solvent is used, the amount used can be appropriately adjusted according to the desired film thickness of the silicon oxide film. The amount is preferably 1,000 parts by weight or less, particularly preferably 500 parts by weight or less, based on 1 part by weight of the total of the silicon compound and carbamate compound. If the amount exceeds 1,000 parts by weight, it may be difficult to form a coating solution, which is not preferable.

  A surfactant can be added to the above composition as necessary within a range not impairing the object and function of the present invention. Such surfactants can be cationic, anionic, amphoteric, or nonionic. Among these, nonionic surfactants improve the wettability of the composition to the object to be coated, improve the leveling of the applied film, and prevent the occurrence of coating crushing and distortion skin. It can be preferably used in terms of usefulness. Examples of the nonionic surfactant include a fluorine-based surfactant having a fluorinated alkyl group or a perfluoroalkyl group, or a polyether alkyl-based surfactant having an oxyalkyl group.

Examples of the fluorosurfactant include F-top EF301, EF303, EF352 (manufactured by Shin-Akita Kasei Co., Ltd.), MegaFuck F171, F173 (manufactured by Dainippon Ink Co., Ltd.), Asahi Guard AG710 (Asahi Glass) ), FLORARD FC-170C, FC430, FC431 (Sumitomo 3M), Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC105, Asahi Glass ( Ltd.)), BM-1000, the 1100 (B.M-Chemie Co.), Schsego-Fluor (Schwegmann Co., _{Ltd.), C 9 F 19 CONHC 12} H 25, 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 can be mentioned. (Here, Pluronic L-35: manufactured by Asahi Denka Kogyo Co., Ltd., polyoxypropylene-polyoxyethylene block copolymer, average molecular weight 1,900; Pluronic P-84: manufactured by Asahi Denka Kogyo Co., Ltd., polyoxy Propylene-polyoxyethylene block copolymer, average molecular weight 4,200; Tetronic-704: manufactured by Asahi Denka Kogyo Co., Ltd., N, N, N ′, N′-tetrakis (polyoxypropylene-polyoxyethylene block copolymer) Polymer), average molecular weight 5,000.)
Examples of the polyether alkyl surfactant include polyoxyethylene alkyl ether, polyoxyethylene allyl ether, polyoxyethylene alkylphenol ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, oxyethyleneoxy A propylene block polymer etc. can be mentioned. Specific examples of these polyether alkyl surfactants include Emulgen 105, 430, 810, 920, Rhedol SP-40S, TW-L120, Emanol 3199, 4110, Excel P-40S, Bridge 30. 52, 72, 92, Alassell 20, Emazole 320, Tween 20, 60, Merge 45 (all manufactured by Kao Corporation), Noniball 55 (manufactured by Sanyo Chemical Co., Ltd.), and the like. .

  Nonionic surfactants other than the above include, for example, polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyalkylene oxide block copolymers, and the like. Specifically, Chemistat 2500 (Sanyo Chemical Industries, Ltd.) Manufactured), SN-EX9228 (manufactured by San Nopco), Nonal 530 (manufactured by Toho Chemical Co., Ltd.), and the like. The amount of the surfactant used is preferably 10 parts by weight or less, particularly preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the total of the silicon compound and the carbamate compound. Here, when the amount exceeds 10 parts by weight, the resulting composition tends to foam, and thermal discoloration may occur, which is not preferable.

  Moreover, the colloidal silica disperse | distributed to the appropriate dispersion medium can also be added to the composition of this invention. This colloidal silica is used to change the dynamic viscoelastic properties of the composition of the present invention, and can be varied depending on the coating method and the desired film thickness obtained. When colloidal silica is used, the amount used is preferably selected and used appropriately in consideration of dispersibility with the silicon compound used in the present invention and optional components. In addition, the composition of the present invention has the purpose of preventing gelation and thickening of the composition, improving the heat resistance, chemical resistance, hardness, and adhesion of the resulting silicon oxide film, and further preventing static electricity. Fine powders of metal oxides such as aluminum oxide, zirconium oxide, and titanium oxide can be appropriately blended.

  After the composition of the present invention is applied to a substrate, it is converted into a silicon dioxide film by light irradiation and / or heating. The application method is not particularly limited, but usually, in addition to spin coating, spray coating, curtain coating, and bar coating, methods such as printing and ink jet coating can be applied. For semiconductor applications, spin coating is usually preferred. The coating environment is not particularly limited, but may be performed in an inert atmosphere such as nitrogen, argon or helium, a reducing gas atmosphere containing hydrogen, or a general air atmosphere.

  The applied silicon compound is converted into a silicon dioxide film by heating and / or light irradiation. As processing conditions, in the case of heating, heat treatment is usually performed in air or in an inert atmosphere such as nitrogen. The heating is performed using a general heating means such as a hot plate or an oven. The heating temperature is preferably 100 to 1,000 ° C, more preferably 200 to 900 ° C, and still more preferably 300 to 800 ° C. The heat treatment time is preferably 1 to 300 minutes, more preferably 5 to 120 minutes, and further preferably 10 to 60 minutes. When the heating temperature is lower than 100 ° C., the film density is low and the silicon compound film may not be sufficiently formed into a silicon dioxide film. On the other hand, when the heating temperature is higher than 1,000 ° C., the resulting silicon dioxide film is cracked. Is not preferable. If the heating time is shorter than 1 minute, the oxidation reaction may be insufficient, while it is not necessary to heat for more than 300 minutes.

  The treatment may be a combination of heating at a constant temperature in nitrogen and heating at a constant temperature in air. When irradiating light, in addition to visible light, ultraviolet light, far ultraviolet light, low pressure or high pressure mercury lamp, deuterium lamp or rare gas discharge light such as argon, krypton, xenon, YAG laser, argon laser, An excimer laser such as a carbon dioxide laser, XeF, XeCl, XeBr, KrF, KrCl, ArF, or ArCl can be used as a light source. As these light sources, those having an output of 10 to 5,000 W are preferably used. Usually 100 to 1,000 W is sufficient. Although the wavelength of these light sources will not be specifically limited if the silicon compound in a composition or a coating film absorbs to some extent, 170 nm-600 nm are preferable. Furthermore, when using both light and heat, the temperature when performing the light irradiation treatment is preferably room temperature to 500 ° C. or less. The processing time is about 0.1 to 60 minutes. The light irradiation treatment varies depending on the wavelength of the irradiation light, and is preferably performed in nitrogen when the wavelength is 220 nm or less, and is preferably performed in air when the wavelength is 220 nm or more.

  In the method for forming trench isolation according to the present invention, the composition is applied onto a substrate having a trench structure, for example, a spray method, a roll coating method, a curtain coating method, a spin coating method, a screen printing method, an offset printing method, an inkjet method. Coating is performed by an appropriate method such as a method, and the film thickness after being subjected to the above heating and / or light irradiation is preferably 5 to 1,000 nm, more preferably about 25 to 500 nm. To do. In addition, when a composition contains a solvent, the said film thickness should be understood as a film thickness after solvent removal.

  Examples of a method for forming a trench on a substrate include a method known per se, for example, a method including depositing an insulating film made of the mask nitride film / pad oxide film described above. The trench can preferably have a line width of 30 to 100,000 nm, more preferably 50 to 50,000 nm. The aspect ratio of the trench is preferably 50 or less, more preferably 10 or less. Moreover, in order to form a coating film of the composition of the present invention on the substrate with good adhesion and denseness, it is preferable to perform a light irradiation treatment at least once before and after coating. In such light irradiation treatment, in addition to visible light, ultraviolet light, far ultraviolet light, low pressure or high pressure mercury lamp, deuterium lamp, or discharge light of rare gas such as argon, krypton, xenon, YAG laser, argon laser An excimer laser such as carbon dioxide laser, XeF, XeCl, XeBr, KrF, KrCl, ArF, ArCl, or the like can be used as a light source. As these light sources, those having an output of 10 to 5,000 W are preferably used. Usually 100 to 1,000 W is sufficient. Although the wavelength of these light sources will not be specifically limited if the polysilane compound in a composition or a coating film absorbs to some extent, 170 nm-600 nm are preferable. The temperature when performing the light irradiation treatment is preferably room temperature to 300 ° C. The processing time is about 0.1 to 30 minutes. These light irradiation treatments are preferably performed in the same atmosphere as in the film formation step of the silicone resin.

  The trench substrate used for forming the trench isolation of the present invention is not particularly limited. Examples of substrates include ordinary quartz, borosilicate glass, soda glass, transparent electrodes such as ITO, metal substrates such as gold, silver, copper, nickel, titanium, aluminum, and tungsten, and these metals or these metals. It is possible to use glass having a surface of the above oxide or a plastic substrate.

  The surface on which the coating film is formed may be a flat surface or a non-planar surface having a step, and the form is not particularly limited. In the present invention, as described above, the silicon dioxide film is buried without generating local vacancies inside the trench. In addition, when the silicone resin coating film is irradiated with light, if a part of the coating film is selectively irradiated with light by using a photomask having a desired pattern, trench isolation is applied only to an arbitrary portion. It is also possible to form

  According to the present invention, a silicon dioxide film free from local voids can be formed regardless of the area and shape of the substrate, and can be suitably used for manufacturing a device that requires high reliability. Further, the method of the present invention is low in cost because an expensive apparatus such as a vacuum apparatus is not necessary. According to the present invention, trenches having an aspect ratio of 2 or more that could not be realized by the conventional method can be easily filled.

  Hereinafter, the present invention will be described in detail by way of examples. The present invention is not limited in any way by these examples.

Synthesis example 1
A 500 mL four-necked flask was equipped with a dual condenser, an air inlet tube, a thermometer, and a septum, and 200 ml of toluene was charged in a nitrogen atmosphere. After this reaction system was cooled to −60 ° C. with a dry ice-acetone bath, liquefied H ₂ SiCl ₂ (24.3 g, 240 mmol) was injected with a syringe. At the same temperature of −60 ° C., distilled water (4.10 ml, 228 mmol) was added dropwise over 3 minutes, and then the temperature was raised to room temperature over 2 hours. Furthermore, it stirred at room temperature for 1 hour as it was. Thereafter, the reaction solution was transferred to a separatory funnel, the toluene layer was washed 5 times with 100 ml of distilled water, the toluene layer was dried over magnesium sulfate, and then filtered to obtain a silicon resin solution.
The obtained silicone resin solution was distilled under reduced pressure at 150 mmHg, 80 ° C. and 0.5 mmHg to 80 ° C. to obtain 198 g of a distillate (I). ¹ H-NMR, ²⁹ Si-NMR, and measurement were performed on the distillate (I). ^{In 1} H-NMR measurement, a peak derived from Si—H ₂ was observed in the region of 4.8 to 4.7 ppm. Moreover, from the integration ratio of the peak derived from Si—H ₂ appearing in the region of 4.8 ppm to 4.7 ppm and the peak derived from toluene, 3.0% by weight of silicon resin was dissolved in the distillate (A). Turned out to be.

Synthesis example 2
In the atmosphere, 50 g of the above distillate (ii) (containing 3.0% (w / w) of silicon resin with respect to toluene) is taken in a 50 ml cocoon flask, stirred at room temperature, and triethylamine is added to toluene. Then, 0.33 ml of a 1% (w / w) solution was added dropwise over 3 minutes, and then stirred at room temperature for 16 hours.
Then, 1% oxalic acid water is added to the reaction solution to stop the reaction, and then transferred to a separatory funnel, 30 ml of n-butyl ether is further added, the water tank is separated, 1% oxalic acid water is added again, and liquid separation is performed. Then, it was washed with distilled water three times. Thereafter, the solvent was distilled off, and further, the solvent was replaced with n-butyl ether three times under reduced pressure to obtain 14.3 g of a uniform and transparent silicon resin-n-butyl ether solution (b).

¹ H-NMR, ²⁹ Si-NMR, and measurement were performed on the silicon resin-n-butyl ether solution (b). ^{In 1} H-NMR measurement, a broad peak derived from Si—H ₂ was observed in the region of 4.8 ppm to 4.6 ppm, and a broad peak derived from Si—H was observed in the region of 4.5 ppm to 4.3 ppm. The integration ratio of both was 51:49. On the other hand, in the ²⁹ Si-NMR measurement, a peak of H ₂ Si (—O) ₂ and a HSi (—O) ₃ peak in the region of −80 ppm to 87 ppm are observed in the region of −47 ppm to −51 ppm, and the integral ratio of both Was 51:49. Moreover, from the integral ratio of the peak derived from n-butyl ether by ¹ H-NMR measurement, it was found that 10.0% of the silicon resin was dissolved in the silicon resin-n-butyl ether solution (B).
Moreover, about the silicon resin n-butyl ether solution (b), when the chlorine concentration in a solution was measured by the ion chromatography analysis by a combustion gas absorption method, it turned out that it is 1 ppm or less of a measurement method detection limit.

Synthesis example 3
A 300 mL three-necked flask is equipped with an air introduction tube and a dropping funnel. In a nitrogen atmosphere, 100 ml of dichloromethane is added, 120 mg of N, N-dimethylaminopyridine is added, and the amount of amine shown in Table 1 is added and stirred. Next, 21.8 g (100 mmol) of di-t-butyl dicarbonate was dissolved in 20 ml of methylene chloride at room temperature and added dropwise over 15 minutes.
After completion of the dropwise addition, the mixture was stirred at room temperature for 1 hour, and then the reaction solution was transferred to a separatory funnel, 100 ml of distilled water was added, and the methylene chloride layer was washed 5 times in total. Subsequently, the organic layer was dried over magnesium sulfate, and then methylene chloride was distilled off. The reaction product carbamate compounds (2-a) to (2-1) represented by the formula (2) were obtained in the yields shown in Table 1.

  Next, the carbamate compounds (2-a) to (2-1) in the above table were added in the addition amounts shown in Table 1 to 10 g of the silicone resin-n-butyl ether solution (b) in Synthesis Example 2, respectively. The uniform liquids (Lo-a) to (Ro-1) were used. Although it was allowed to stand at room temperature for 1 day, no change in appearance was observed.

Evaluation Example 1
For the carbamate compound-added silicon resin-n-butyl ether solutions (b-a) to (b-l) obtained in Synthesis Example 3 and the carbamate compound-free silicon resin-n-butyl ether solution (b), 0.5 μm PTFE was used. After filtration through a filter, a silicon wafer was spin-coated at a rotation speed of 1,000 rpm to form a film, and then baked at 100 ° C. for 1 hour to obtain silicon dioxide films (ha) to (ha) and (ha). : No addition). When the silicon dioxide film obtained here was analyzed by FT-IR, in the case of the silicon dioxide film without addition of a carbamate compound (c), there was a peak derived from the Si—H group observed in the vicinity of 2,200 cm ^−1. In contrast to the observation, in the silicon dioxide films (ha) to (hal) formed by 12 kinds of liquids to which the carbamate compound was added, a peak derived from the Si—H group was present in the vicinity of 2,200 cm ^−1. Was hardly observed. In the case of no addition of a carbamate compound and a silicon film (c), a peak derived from Si—O—Si groups observed in the vicinity of 1,000 to 1,100 cm ⁻¹ is observed, whereas a carbamate compound is added. In the silicon dioxide films (ha) to (ha) formed by the 12 kinds of liquids, the peak range derived from the Si—O—Si group further expands, and ranges from 1,000 to 1,200 cm ⁻¹ . It was found that the Si—O—Si bond increased relatively.

Evaluation example 2
Regarding the silicon dioxide films (ha) to (ha) and (ha: unadded) obtained in the evaluation example 1, the thickness of each silicon dioxide film was measured. It turned out to be. Next, silicon dioxide films (ha) to (ha) and (ha: no addition) were infiltrated in a 1% hydrofluoric acid solution for 10 seconds and observed after washing with distilled water. The presence of the silicon dioxide film on the substrate could not be confirmed in the film (c: additive-free) and the silicon dioxide films (c-a), (c-b), and (c-c). In (d) to (ha), it was confirmed that the oxide film remained on the substrate without being etched.

Evaluation Example 3
When the ESCA analysis was performed on the silicon dioxide films (ha) to (ha) and (ha: no addition) obtained in Evaluation Example 1, elements other than silicon and oxygen atoms were observed from any film. Was not.

Synthesis example 4
30.1 g of tetramethoxysilane and 20.1 g of methyltrimethoxysilane were dissolved in 154 g of propylene glycol monopropyl ether and stirred to stabilize the temperature of the solution at 60 ° C. To this solution, an aqueous solution in which 0.12 g of maleic acid was dissolved in 15.7 g of ion exchange water was added over 1 hour. Then, it was made to react at 60 degreeC for 4 hours, and the reaction liquid was cooled to room temperature. And 51 g of the solution containing methanol by-produced by the reaction was distilled off from the reaction solution under reduced pressure, and 51 g of propylene glycol monopropyl ether was added to obtain a reaction product solution (d).
To 10 g of this reaction product liquid (d), the carbamate compounds of Table 2 synthesized in Synthesis Example 3 were added in the amounts shown in Table 2, respectively, and uniform liquids (ni-d) to (ni-l) and did. Although it was allowed to stand at room temperature for 1 day, no change in appearance was observed.

Evaluation Example 4
For the carbamate compound-added silicon resin-n-butyl ether solutions (ni-d) to (ni-l) and the carbamate compound-free silicon resin-n-butyl ether solution (d) obtained in Synthesis Example 4, 0.5 μm PTFE was used. After filtration with a filter, a film was formed on a silicon wafer by spin coating at a rotation speed of 1,000 rpm, and then baked at 100 ° C. for 1 hour to obtain silicon dioxide films (ho-d) to (hol) and (e: Additive-free) was obtained. Regarding the silicon dioxide films (ho-d) to (hol) and (e: no addition) obtained here, the thicknesses of the silicon dioxide films were measured, respectively, and the film thickness was about 300 nm. There was found. Next, silicon dioxide films (ho-d) to (hol) and (e: non-added) were infiltrated with a 1% hydrofluoric acid solution for 10 seconds and observed after washing with distilled water. Silicon dioxide In the film (e: no addition), the presence of the silicon dioxide film could not be confirmed on the substrate, while in the silicon dioxide films (hod) to (hol), the oxide film was not etched and remained on the substrate. It was confirmed that
With respect to the silicon dioxide film (e: additive-free) and the silicon dioxide films (ho-d), (ho-g), (hol), the internal stress of the silicon dioxide film was measured with a Tencor stress meter. However, (e) showed a compressive stress of 80 MPa, (ho-d) 120 MPa, (ho-g) 130 MPa, and (hol) 150 MPa.

Evaluation Example 5
The carbamate compound-added silicon resin-n-butyl ether solution (ni-f) obtained in Synthesis Example 3 above was filtered through a 0.5 μm PTFE filter, then formed on a PET film by spin coating at a rotation speed of 1,000 rpm, and then Baked at 100 ° C. for 1 hour to obtain a silicon dioxide film. The silicon dioxide film obtained here was infiltrated with a 1% hydrofluoric acid solution for 10 seconds, and the film after washing with distilled water was observed. As a result, it was confirmed that the oxide film remained on the substrate without being etched. .
As described above, according to the present invention, a stable silicon resin composition solution can be obtained by adding the carbamate compounds of the above formula (2) to the silicon compound of the above formula (1). It has been found that a silicon dioxide film having a small amount of impurities and a high density can be obtained by forming a film using this and baking at a low temperature.

¹ H-NMR spectrum of the resulting silicone resin in Synthesis Example 1 (cyclic polysiloxane). ²⁹ Si-NMR spectrum of the same silicone resin as obtained above in Synthesis Example 1. ^{1 H-NMR} spectrum of the resulting silicone resin in Synthesis Example 2 (post-polymerization polysiloxanes). ²⁹ Si-NMR spectrum of the same silicone resin as described above obtained in Synthesis Example 2.

Claims (4)

A silicon oxide-forming composition comprising a silicon compound represented by the following formula (1) and a carbamate compound represented by the following formula (2).
(R ¹ ₃ SiO _0.5 ) _k (R ² ₂ SiO) _m (R ³ SiO _1.5 ) _n (1)
(In formula (1), R ¹ , R ² and R ³ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, or a linear or branched alkyl group having 1 to 20 carbon atoms. A linear or branched alkyl halide group having 1 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, or a monovalent halogenated aromatic hydrocarbon group having 6 to 20 carbon atoms And the sum of k, m and n is 1.)

(In formula (2), R ⁴ and R ⁵ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms, or a monovalent aromatic having 6 to 20 carbon atoms. A hydrocarbon group or a monovalent halogenated aromatic hydrocarbon group having ⁶ to 20 carbon atoms, and R ⁶ represents a substituted or unsubstituted organic group having 1 to 20 carbon atoms.) A method for forming a silicon dioxide film, comprising applying the composition for forming silicon oxide according to claim 1 to a substrate, and heating and / or irradiating with light. The method for forming a silicon dioxide film according to claim 2, wherein the silicon dioxide film has a compressive stress. A method for forming trench isolation for electrically separating a plurality of semiconductor elements formed on a silicon substrate, wherein the composition is coated on the substrate so that the trench in the substrate is filled. , Followed by heating and / or light irradiation.

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