JP2008280413A - Thin film-forming composition and thin film-forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin film-forming composition which hardly causes the rise in viscosity with time and hardly causes the variability of thickness of a coating in forming a thin film, and accordingly enables surely and stably obtaining a thin film having a uniform thickness. <P>SOLUTION: The thin film-forming composition comprises an alkoxysilane condensate (A) having a weight average molecular weight of 500-5,000, a viscosity modifier (B) and composed of a straight-chain polysiloxane having a weight average molecular weight in the range of 10,000-500,000 and a skeleton represented by formula (1) (wherein R<SB>x</SB>and R<SB>y</SB>are each hydrogen or a 1-30C nonhydrolyzable organic group and R<SB>x</SB>and R<SB>y</SB>may be the same or different and n is an integer). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a composition for forming a thin film and a thin film forming method for forming a thin film used for an insulating film or the like in an electronic device such as a semiconductor device, using an alkoxysilane condensate. The present invention relates to a thin film forming composition and a thin film forming method capable of achieving uniformity.

  In an electronic device such as a semiconductor device, it is necessary to form a thin film having excellent insulating properties in order to reduce the size and thickness. In addition, it is necessary to form an insulating film having a fine pattern shape in a passivation film, a gate insulating film, or the like of a semiconductor device. Therefore, various thin film forming compositions using alkoxysilane condensates have been proposed as photosensitive resin compositions for forming thin films that can be patterned.

  For example, Patent Document 1 listed below discloses a photosensitive composition for forming a thin film mainly comprising 1) an alkali-soluble siloxane polymer, 2) a compound that generates a reaction accelerator by light, and 3) a solvent. This 1) alkali-soluble siloxane polymer is an alkoxysilane condensate obtained by removing water and catalyst from a reaction solution obtained by hydrolyzing and condensing water and a catalyst with alkoxysilane.

In forming a thin film using the thin film forming composition containing the alkoxysilane condensate and the solvent as described above, the thin film forming composition is first applied to a substrate to a predetermined thickness. Next, it is dried and further fired to form a hard and dense thin film. In the case of a thin film forming composition that requires patterning as described in Patent Document 1, the thin film forming photosensitive composition is applied onto a substrate, dried, and selectively exposed through a mask. To do. Thereafter, the exposed composition layer is developed with an alkaline solution. Next, after development, the remaining composition layer is heated to obtain a hard and dense thin film with a fine pattern.
Japanese Patent Laid-Open No. 6-148895

  However, in any of the formation of a fine patterned thin film using the photosensitive composition for forming a thin film described in Patent Document 1 and the thin film forming method using the alkoxysilane condensate described above that does not require patterning, the thin film is formed. At this time, a relatively large amount of silanol groups (SiOH groups) tended to remain in the alkoxysilane condensate in the thin film forming composition applied. Therefore, prior to coating, during storage and the like, condensation further progressed due to moisture in the air and environmental temperature, the molecular weight of the alkoxysilane condensate increased, and the viscosity of the thin film forming composition tended to increase. . As a result, even when an attempt is made to apply the thin film-forming composition to a predetermined thickness on the substrate during thin film formation, the coating thickness varies, and the final thin film and the fine patterned thin film vary in film thickness. There was a problem.

  The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to form a thin film composition using an alkoxysilane condensate, which is unlikely to increase in viscosity over time. It is an object of the present invention to provide a thin film forming composition and a thin film forming method capable of forming a thin film having a uniform thickness with high accuracy, which hardly causes variations.

  The composition for forming a thin film according to the present invention has an alkoxysilane condensate having a weight average molecular weight of 500 to 5,000 and a weight average molecular weight in the range of 10,000 to 500,000 and has a skeleton represented by the following formula (1). It contains a viscosity modifier (B) comprising a chain polysiloxane, and a solvent for dissolving the alkoxysilane condensate (A) and the viscosity modifier (B).

In formula (1), R _x and R _y represent hydrogen or a non-hydrolyzable organic group having 1 to 30 carbon atoms, R _x and R _y may be the same or different, and n is an integer It is.

  In the composition for forming a thin film according to the present invention, various alkoxysilane condensates can be used as the alkoxysilane condensate. Preferably, the alkoxysilane condensate (A) is represented by the following formula (2). Is a condensate of alkoxysilane represented by

Si (R ₁ ) _p (R ₂ ) _q (R ₃ ) _4-pq Formula (2)
In the above formula (2), R ₁ represents hydrogen or a non-hydrolyzable organic group having 1 to 30 carbon atoms, R ₂ represents an alkoxy group, and R ₃ represents a hydrolyzable group other than the alkoxy group. , P represents an integer of 0 to 3, q represents an integer of 1 to 4, and p + q ≦ 4. When p is 2 or 3, the plurality of R ₁ may be the same or different. When q is 2 to 4, a plurality of R ₂ may be the same or different. When p + q ≦ 2, the plurality of R ₃ may be the same or different.

  In the composition for forming a thin film according to the present invention, the viscosity modifier (B) is preferably blended at a ratio of 5 to 100 parts by weight with respect to 100 parts by weight of the alkoxysilane condensate (A). If it is less than 5 parts by weight, the effect of suppressing the increase in viscosity may not be sufficient, and if it exceeds 100 parts by weight, the increase in viscosity can be suppressed, but the resulting thin film contains a large amount of viscosity modifier, There is a risk that the properties and electrical properties of the thin film will deteriorate.

  The thin film forming method according to the present invention comprises a step of coating the thin film forming composition of the present invention on a substrate to form a thin film forming composition layer and a step of drying the thin film forming composition layer. It is characterized by providing.

  In the thin film forming method according to the present invention, the thin film forming composition layer is preferably heated during or after the drying, whereby a more dense thin film can be obtained.

  Details of the present invention will be described below.

(Alkoxysilane condensate (A))
The alkoxysilane condensate (A) used in the present invention is a relatively low molecular weight alkoxysilane condensate having a weight average molecular weight in the range of 500 to 5,000. A hard thin film can be formed by applying an alkoxysilane condensate solution obtained by diluting the alkoxysilane condensate (A) with a solvent onto a substrate and baking it by a method such as heating. Although it does not specifically limit about the said alkoxysilane condensate (A), A weight average molecular weight needs to be the range of 500-5000. If the weight average molecular weight is less than 500, it is difficult to form a hard and dense thin film, and if it exceeds 5000, gelation tends to occur.

  In addition, in this specification, all the weight average molecular weights of an alkoxysilane condensate and a viscosity modifier (B) are the weight average molecular weights by polystyrene conversion.

  Although it does not specifically limit as said alkoxysilane condensate (A), Preferably, the condensate of the alkoxysilane represented by following formula (2) is used.

Si (R ₁ ) _p (R ₂ ) _q (R ₃ ) _4-pq Formula (2)
In the above formula (2), R ₁ represents hydrogen or a non-hydrolyzable organic group having 1 to 30 carbon atoms, R ₂ represents an alkoxy group, and R ₃ represents a hydrolyzable group other than the alkoxy group. , P represents an integer of 0 to 3, q represents an integer of 1 to 4, and p + q ≦ 4. When p is 2 or 3, the plurality of R ₁ may be the same or different. When q is 2 to 4, a plurality of R ₂ may be the same or different. When p + q ≦ 2, the plurality of R ₃ may be the same or different.

The alkoxy group R ₂ and the hydrolyzable group R ₃ other than the alkoxy group are usually hydrolyzed by heating in the temperature range of room temperature (25 ° C.) to 100 ° C. in the presence of excess water without catalyst. It is a group that can be decomposed to form a silanol group, or a group that can be further condensed to form a siloxane bond.

Examples of the alkoxy group R _2, is not particularly limited, specifically, methoxy group, an ethoxy group, an alkoxy group having 1 to 6 carbon atoms such as a propoxy group.

The hydrolyzable group R ₃ other than the alkoxy group is not particularly limited, specifically, chlorine, halogeno group such as bromine, an amino group, and a hydroxyl group or a carboxyl group.

The non-hydrolyzable organic group R ₁ is not particularly limited, and examples thereof include an organic group having 1 to 30 carbon atoms that hardly causes hydrolysis and is a stable hydrophobic group. As the organic group having 1 to 30 carbon atoms which is a stable hydrophobic group, methyl group, ethyl group, propyl group, butyl group, hexyl group, cyclohexyl group, octyl group, pentyl group, decyl group, dodecyl group, tetradecyl group, Alkyl groups having 1 to 30 carbon atoms such as hexadecyl group, octadecyl group and eicosyl group, and alkyl halide groups such as fluorinated, chlorinated and brominated alkyl groups (for example, 3-chloropropyl group, 6-chloropropyl group) , 6-chlorohexyl group, 6,6,6-trifluorohexyl group, etc.), aromatic substituted alkyl groups such as halogen-substituted benzyl groups (for example, benzyl group, 4-chlorobenzyl group, 4-bromobenzyl group, etc.) ), Aryl groups (eg phenyl group, tolyl group, mesityl group, naphthyl group, etc.), vinyl groups and epoxy groups Group, an organic group containing an amino group, and the like organic group containing a thiol group.

  Specific examples of the alkoxysilane include, for example, triphenylethoxysilane, trimethylethoxysilane, triethylethoxysilane, triphenylmethoxysilane, triethylmethoxysilane, ethyldimethylmethoxysilane, methyldiethylmethoxysilane, ethyldimethylethoxysilane, methyldiethyl. Ethoxysilane, phenyldimethylmethoxysilane, phenyldiethylmethoxysilane, phenyldimethylethoxysilane, phenyldiethylethoxysilane, methyldiphenylmethoxysilane, ethyldiphenylmethoxysilane, methyldiphenylethoxysilane, ethyldiphenylethoxysilane, tert-butoxytrimethylsilane, butoxy Trimethylsilane, dimethylethoxysilane, methoxydimethylvinylsilane , Ethoxydimethylvinylsilane, diphenyldiethoxysilane, phenyldiethoxysilane, dimethyldimethoxysilane, diacetoxymethylsilane, diethoxymethylsilane, 3-chloropropyldimethoxymethylsilane, chloromethyldiethoxymethylsilane, diethoxydimethylsilane Diacetoxymethylvinylsilane, diethoxymethylvinylsilane, diethoxydiethylsilane, dimethyldipropoxysilane, dimethoxymethylphenylsilane, methyltrimethoxysilane, methyltriethoxysilane, methyl-tri-n-propoxysilane, ethyltrimethoxysilane, Ethyltriethoxysilane, ethyl-tri-n-propoxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyl-tri-n Propoxysilane, butyltrimethoxysilane, butyltriethoxysilane, butyltripropoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, isobutyltripropoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-hexyl Tripropoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, cyclohexyltripropoxysilane, octyltrimethoxysilane, octyltriethoxysilane, octyltripropoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, dodecyltripropoxysilane, tetra Decyltrimethoxysilane, tetradecyltriethoxysilane, tetradecyltripropoxysilane, hex Sadecyltrimethoxysilane, hexadecyltriethoxysilane, hexadecyltripropoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, octadecyltripropoxysilane, eicosyldecyltrimethoxysilane, eicosyltriethoxysilane, eicosyltripropoxy Silane, 6-chlorohexyltrimethoxysilane, 6,6,6-trifluorohexyltrimethoxysilane, benzyltrimethoxysilane, 4-chlorobenzyltrimethoxysilane, 4-bromobenzyltri-n-propoxysilane, phenyltrimethoxy Silane, phenyltriethoxysilane; vinyltrimethoxysilane, vinyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ- Glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, γ-amino Propyltrimethoxysilane, γ-aminopropyltriethoxysilane, methyltriacetoxysilane, ethyltriacetoxysilane, N-β-phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltri Methoxysilane, triethoxysilane, trimethoxysilane, triisopropoxysilane, tri-n-propoxysilane, triacetoxysilane, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraiso Examples include propoxysilane and tetraacetoxysilane. An alkoxysilane condensate obtained by condensing these alkoxysilanes is more preferably used. In constituting the alkoxysilane condensate (A), it is sufficient that at least one alkoxysilane is used, and therefore two or more alkoxysilanes may be used.

(Viscosity modifier (B))
The viscosity modifier (B) used in the present invention is a linear polysiloxane having a weight average molecular weight in the range of 10,000 to 500,000 and having a skeleton represented by the following formula (1).

In formula (1), R _x and R _y represent hydrogen or a non-hydrolyzable organic group having 1 to 30 carbon atoms, R _x and R _y may be the same or different, and n is an integer It is.

As the non-hydrolyzable organic group having 1 to 30 carbon atoms, the non-hydrolyzable organic group exemplified as R ₁ shown in the above-described formula (2) can be similarly used. That is, the non-hydrolyzable organic groups R _x and R _y are not particularly limited, but the organic groups exemplified as the organic groups having 1 to 30 carbon atoms that are difficult to cause hydrolysis and are stable composition groups are mentioned. It can be used similarly.

  When the weight average molecular weight is less than 10,000, the effect of suppressing the change in the viscosity of the thin film forming composition is reduced. When the weight average molecular weight exceeds 500,000, the viscosity adjusting agent (B) is added to the solvent in the thin film forming composition. It becomes difficult to dissolve, and processability is greatly reduced. The weight average molecular weight is more preferably in the range of 20000 to 100,000 in order to enhance the viscosity increase suppressing effect and further suppress the decrease in workability.

  As described above, the linear polysiloxane represented by the formula (1) is used when, for example, a polysiloxane that is a condensate of trialkoxysilane or tetraalkoxysilane is used as a viscosity modifier. In itself, a crosslinked structure is easily formed. Therefore, the solubility in the composition for forming a thin film is lowered, and it is difficult to obtain the effect of suppressing the increase in viscosity. Further, when a trialkoxysilane or tetraalkoxysilane polysiloxane is used, the amount of residual silanol groups also increases, which also increases the molecular weight over time.

  Therefore, in the present invention, as described above, a linear polysiloxane having a skeleton represented by the formula (1), which is a condensate of dialkoxysilane, is used as the viscosity modifier (B). The increase in viscosity over time is effectively suppressed.

  The viscosity modifier (B) composed of a linear polysiloxane having a skeleton represented by the above formula (1) is a hydrolysis-condensation product of dialkoxysilane. Examples of such dialkoxysilane include, but are not limited to, diphenyldiethoxylane, phenyldiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diacetoxymethylsilane, diethoxymethylsilane, and 3-chloropropyldimethoxymethyl. Examples thereof include silane, chloromethyldiethoxymethylsilane, diethoxydimethylsilane, diacetoxymethylvinylsilane, diethoxymethylvinylsilane, diethoxydiethylsilane, dimethyldipropoxysilane, and dimethoxymethylphenylsilane. In obtaining the viscosity modifier (B), at least one of these alkoxysilanes is used, but two or more dialkoxysilanes may be used.

  In obtaining the viscosity modifier (B), as in the case of obtaining the alkoxysilane condensate (A), at least one dialkoxysilane, a catalyst for hydrolysis condensation reaction, water, an appropriate solvent, Are mixed and reacted under heating, and then the alcohol produced by the condensation reaction with water and residual water may be removed. Examples of the catalyst include oxalic acid, formic acid, maleic acid, fumaric acid, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, adipic acid, sebacic acid, butyric acid, Organic acids such as oleic acid, stearic acid, linoleic acid, linolenic acid, salicylic acid, benzoic acid, p-aminobenzoic acid, p-toluenesulfonic acid, phthalic acid, sulfonic acid, tartaric acid, trifluoromethanesulfonic acid, hydrochloric acid, phosphoric acid, An appropriate acid such as an inorganic acid such as nitric acid, boric acid, sulfuric acid, or hydrofluoric acid can be used. Moreover, the said solvent can also use the appropriate solvent mentioned as a below-mentioned solvent (C).

  The blending ratio of the viscosity modifier (B) is desirably 5 to 100 parts by weight with respect to 100 parts by weight of the alkoxysilane condensate (A). If it is less than 5 parts by weight, the effect of suppressing the increase in viscosity may not be obtained. If it exceeds 100 parts by weight, the viscosity becomes too high, and the content of the viscosity modifier (B) becomes too high. The quality of the thin film may deteriorate.

(Solvent (C))
In the present invention, as the solvent (C) used in the thin film forming composition, an appropriate solvent capable of dissolving the components blended in the thin film forming composition can be used. That is, an appropriate solvent capable of dissolving the alkoxysilane condensate (A) and the viscosity modifier (B) and further dissolving other components to be added can be used as necessary.

  Examples of such a solvent include, but are not limited to, aromatic hydrocarbon compounds such as benzene, xylene, toluene, ethylbenzene, styrene, trimethylbenzene, and diethylbenzene; cyclohexane, cyclohexene, dipentene, n-pentane, isopentane, n- Saturated or unsaturated hydrocarbon compounds such as hexane, isohexane, n-heptane, isoheptane, n-octane, isooctane, n-nonane, isononane, n-decane, isodecane, tetrahydronaphthalene, squalane; diethyl ether, di-n-propyl Ether, di-isopropyl ether, dibutyl ether, ethyl propyl ether, diphenyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene Recall dibutyl ether, diethylene glycol methyl ethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol dibutyl ether, dipropylene glycol methyl ethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol Methyl ethyl ether, tetrahydrofuran, 1,4-dioxane, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, dipropylene glycol methyl ether acetate, diethylene glycol monoethyl ether acetate, ethylcyclohexane, methylcyclohexane, p Menthane, o-menthane, m-menthane; ethers such as dipropyl ether, dibutyl ether; acetone, methyl ethyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, methyl amyl ketone, cyclopentanone, cyclohexanone, cycloheptanone, etc. Ketones: Esters such as ethyl acetate, methyl acetate, butyl acetate, propyl acetate, cyclohexyl acetate, methyl cellosolve, ethyl cellosolve, butyl cellosolve, ethyl lactate, propyl lactate, butyl lactate, isoamyl lactate, butyl stearate, etc. Is mentioned. These solvents may be used independently and 2 or more types may be used together.

  The blending ratio of the solvent (C) can be set to an appropriate ratio as long as it can be applied on a substrate and the like to form a thin film-forming composition layer having a predetermined thickness. It is desirable to blend the solvent so that the solid content concentration is 0.5 to 60% by weight, more preferably about 2 to 40% by weight.

(Preferred compound to be added)
In the composition for forming a thin film according to the present invention, it is preferable to add a compound (D) that can react with the alkoxysilane condensate (A) and reduce residual SiOH groups. Such a compound (D) is at least one selected from the group consisting of monofunctional alkoxysilane compounds, monofunctional silanol compounds, monofunctional epoxy compounds, monofunctional epoxy compounds and monofunctional isocyanate compounds. Can be mentioned.

  By adding the compound (D), it is possible to reduce the remaining SiOH groups, and thereby it is possible to more effectively suppress an increase in viscosity during storage.

  The monofunctional alkoxysilane compound is not particularly limited, but trimethylmethoxysilane, trimethylethoxysilane, trimethylpropoxysilane, triethylmethoxysilane, triethylethoxysilane, triethylpropoxysilane, dimethylethoxysilane, diethylethoxysilane, dimethylmethoxysilane. , Dimethylethoxysilane, methylmethoxysilane, methylethoxysilane, ethylmethoxysilane, ethylethoxysilane, diisopropylethoxysilane, dimethylaminomethylethoxysilane, diphenylmethylethoxysilane, diphenylmethylmethoxysilane, diphenylethylmethoxysilane, diphenylethylethoxysilane , Triphenylmethoxysilane, triphenylethoxysilane, n-oct Decyl dimethyl silane, octyl dimethyl silane, phenyl dimethyl methoxysilane, phenyl dimethyl ethoxy silane, trimethyl acetoxy silane, and tri propyl methoxy silane. Among them, since the proportion of SiOH groups in the component (X) can be further reduced, trimethylmethoxysilane, trimethylethoxysilane, triethylmethoxysilane, triethylethoxysilane, dimethylethoxysilane, diethylethoxysilane, dimethylmethoxysilane Dimethylethoxysilane, methylmethoxysilane, methylethoxysilane, ethylmethoxysilane, and ethylethoxysilane are preferably used.

  The monofunctional silanol compound is not particularly limited, and examples thereof include trimethylsilanol, triethylsilanol, triphenylsilanol, and t-butyldimethylsilanol. Of these, trimethylsilanol and triethylsilanol are preferably used because the proportion of SiOH groups present in component (X) can be further reduced.

  The monofunctional epoxy compound is not particularly limited, but is methyl glycidyl ether, ethyl glycidyl ether, 2-ethylhexyl glycidyl ether, butyl glycidyl ether, decyl glycidyl ether, phenyl-2-methyl glycidyl ether, cetyl glycidyl ether, stearyl glycidyl ether. Ether, p-sec-butylphenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, phenyl glycidyl ether, orthocresyl glycidyl ether, metapatacridyl glycidyl ether, glycidyl methacrylate, isopropyl glycidyl ether, allyl glycidyl ether be able to. As a commercial item of the said monofunctional epoxy compound, the brand name "Epiol M" (methyl glycidyl ether) by Nippon Oil & Fats Co., Ltd., brand name "Epiol EH" (2-ethylhexyl glycidyl ether), etc. are mentioned. Of these, methyl glycidyl ether and ethyl glycidyl ether are preferably used because the proportion of SiOH groups present in component (X) can be further reduced.

  Although it does not specifically limit as said monofunctional isocyanate compound, Trimethylsilyl isocyanate, a triethylsilyl isocyanate, etc. can be mentioned. Of these, trimethylsilyl isocyanate is preferably used because the proportion of SiOH groups present in component (X) can be further reduced.

  When the above compound (D) is used, the blending ratio thereof may be appropriately set depending on the existing ratio of SiOH groups remaining in the alkoxysilane condensate (A). Preferably, the compound (D) is blended at a ratio of about 1.0 to 150 parts by weight with respect to 100 parts by weight of the alkoxysilane condensate (A). If the amount is less than 1.0 part by weight, the existing ratio of SiOH groups may not be sufficiently lowered. If the amount exceeds 150 parts by weight, the compound (D) becomes excessive and the insulating performance of the thin film may be deteriorated.

(Other ingredients that can be added)
If necessary, other additives may be further added to the thin film forming composition according to the present invention.

  Such additives include fillers, pigments, dyes, leveling agents, antifoaming agents, antistatic agents, UV absorbers, pH adjusters, dispersants, dispersion aids, surface modifiers, plasticizers, plasticizers. Examples include accelerators and sagging inhibitors.

(Compound (E) that generates an acid or a base upon irradiation with light)
Preferably, the thin film forming composition according to the present invention may be used for forming a thin film pattern. In that case, it is desirable to add a compound (E) that generates an acid or a base by irradiation with light to the thin film forming composition. As such a compound (E), a suitable photoacid generator and photobase generator can be used.

  Examples of the photoacid generator include diarylsulfonium salts, triarylsulfonium salts, dialkylphenacylsulfonium salts, diaryliodonium salts, aryldiazonium salts, aromatic tetracarboxylic acid esters, aromatic sulfonic acid esters, nitrobenzyl esters, Examples include oxime sulfonic acid esters, aromatic N-oxyimide sulfonates, aromatic sulfamides, haloalkyl group-containing hydrocarbon compounds, haloalkyl group-containing heterocyclic compounds, and naphthoquinone diazide-4-sulfonic acid esters. These photoacid generators may be used alone or in combination of two or more.

  Although it does not specifically limit as said photobase generator, For example, a cobalt amine complex, o-acyl oxime, a carbamic acid derivative, a formamide derivative, a quaternary ammonium salt, a tosyl amine, a carbamate, an amine imide compound etc. can be mentioned. Specific examples include 2-nitrobenzyl carbamate, 2,5-dinitrobenzyl cyclohexyl carbamate, N-cyclohexyl-4-methylphenylsulfonamide, 1,1-dimethyl-2-phenylethyl-N-isopropylcarbamate, and the like. . These photobase generators may be used alone or in combination of two or more.

  In addition to the photoacid generator and the photobase generator, a sensitizer may be further added in order to increase sensitivity. Specific examples of suitable sensitizers include benzophenone, p, p′-tetramethyldiaminobenzophenone, p, p′-tetraethylaminobenzophenone, 2-chlorothioxanthone, anthrone, 9-ethoxyanthracene, anthracene, pyrene, Perylene, phenothiazine, benzyl, acridine orange, benzoflavin, cetoflavin-T, 9,10-diphenylanthracene, 9-fluorenone, acetophenone, phenanthrene, 2-nitrofluorene, 5-nitroacenaphthene, benzoquinone, 2-chloro-4- Nitroaniline, N-acetyl-p-nitroaniline, p-nitroaniline, N-acetyl-4-nitro-1-naphthylamine, picramide, anthraquinone, 2-ethylanthraquinone, 2-tert-butylant Laquinone, 1,2-benzanthraquinone, 3-methyl-1,3-diaza-1,9-benzanthrone, dibenzalacetone, 1,2-naphthoquinone, 3,3′-carbonyl-bis (5,7 -Dimethoxycarbonylcoumarin) and coronene, but are not limited thereto.

(Thin film formation method)
In forming a thin film using the composition for forming a thin film according to the present invention, first, the composition for forming a thin film of the present invention is applied on a substrate to a predetermined thickness. This coating method is not particularly limited, and an appropriate method such as spin coating, slit coating, die coating, or screen printing can be used. In any case, in the thin film forming composition of the present invention, since the increase in viscosity is suppressed by the action of the viscosity modifier (B) during storage, the thin film forming composition can be stably and uniformly formed. The layer can be easily applied.

  Next, the composition layer for forming a thin film is dried and, if necessary, heated during drying or after drying. Thereby, a dense and hard thin film can be obtained. Although it does not specifically limit in the case of the said heating, For example, what is necessary is just to maintain at the temperature of 200-500 for about 30 minutes-2 hours.

  Further, when patterning is performed using the above-described photoacid generator and photobase generator, exposure and development using an alkaline solution may be performed prior to heating, thereby forming a fine pattern. The thin film can be formed. Even in that case, since the increase in viscosity during storage of the thin film forming composition is suppressed, variation in the coating thickness of the thin film forming composition can be reduced, and a fine pattern with little thickness variation can be formed. it can.

  In the composition for forming a thin film according to the present invention, even if silanol groups remain in the relatively low molecular weight alkoxysilane condensate having a weight average molecular weight of 500 to 5,000, the weight average molecular weight is 10,000 to 10000 as described above. Since the viscosity modifier (B) made of the specific linear polysiloxane having a skeleton similar to that of the alkoxysilane condensate is blended to 500,000, the viscosity of the entire thin film forming composition is blended. The ratio that the alkoxysilane condensate (A) contributes to is relatively low. Therefore, the viscosity change during storage of the composition for forming a thin film is suppressed. Accordingly, when the thin film forming composition is applied to form a thin film, the coating thickness hardly varies, and a thin film having a uniform thickness can be formed with high accuracy.

  Therefore, since the increase in viscosity over time is small, even when stored for a long period of time, it is required that the film thickness be controlled with high accuracy, such as an interlayer insulating film of a semiconductor device. It is possible to provide an optimum thin film forming composition and thin film forming method for forming an insulating film or the like.

  Next, the present invention will be further clarified by giving specific examples and comparative examples of the present invention.

(1) Alkoxysilane condensate As the alkoxysilane condensate (A), the following alkoxysilane condensates A1 to A3 were prepared.

Alkoxysilane condensate A1
To a 100 ml flask equipped with a condenser, 15 g of phenyltriethoxysilane, 10 g of triethoxysilane, 0.5 g of oxalic acid, 7 ml of water and 17 ml of diethylene glycol diethyl ether were added. The solution was stirred using a semicircular mechanical stirrer and reacted at 70 ° C. for 3 hours with a mantle heater. Thereafter, ethanol and residual water generated by a condensation reaction with water were removed using an evaporator. After completion of the reaction, the flask was left to reach room temperature to prepare a component (A1) which is a silicon-containing polymer mixture. The weight average molecular weight of A1 in terms of polystyrene was 1500, and the solid content concentration was 40% by weight.

(Alkoxysilane condensate A2)
An alkoxysilane condensate A2 having a weight average molecular weight of 1200 was obtained in the same manner as the preparation of the alkoxysilane condensate A1 except that triethoxysilane was changed to methyltriethoxysilane. The solid concentration was 40% by weight.

(Alkoxysilane condensate A3)
An alkoxysilane condensate A3 having a weight average molecular weight of 1500 was obtained in the same manner as in the preparation of the alkoxysilane condensate A1 except that phenyltriethoxysilane was changed to methyltriethoxysilane. The solid concentration was 40% by weight.

(2) Viscosity modifier (B)
The following viscosity modifiers B1a to B1d, B2a to B2d, and B3a to B3d were prepared as the viscosity modifier (B).

(Viscosity modifier B1a)
To a 100 ml flask equipped with a condenser, 25 g of dimethyldiethoxysilane, 1.5 g of oxalic acid, 10 ml of water and 20 ml of diethylene glycol diethyl ether (DEDG) were added. The solution was stirred using a semicircular type mechanical stirrer and reacted at 120 ° C. for 6 hours with a mantle heater. Thereafter, ethanol and residual water generated by a condensation reaction with water were removed using an evaporator. After completion of the reaction, the flask was left to reach room temperature to prepare a component (B1) which is a silicon-containing polymer mixture. The weight average molecular weight of B1 in terms of polystyrene was 55000, and the solid content concentration was 30% by weight.

(Viscosity modifiers B1b to B2d)
In the same manner as in the preparation of the viscosity modifier B1a, except that the reaction temperature was changed to 60 ° C., 80 ° C., and 100 ° C., respectively, to obtain viscosity modifiers B1b to B1d. The weight average molecular weights and solid content concentrations of the viscosity modifiers B1b to B1d are as follows.

Viscosity modifier B1b: weight average molecular weight = 6000, solid content concentration = 30% by weight
Viscosity modifier B1c: weight average molecular weight = 18000, solid content concentration = 30% by weight
Viscosity modifier B1d: weight average molecular weight = 30000, solid content concentration = 30% by weight

(Viscosity modifier B2a)
A viscosity modifier B2a was prepared in the same manner as the viscosity modifier B1a except that dimethyldiethoxysilane was changed to diethyldiethoxysilane. Viscosity modifier B2a had a weight average molecular weight of 33,000 and a solid content concentration of 30% by weight.

(Viscosity modifiers B2b to B2d)
In the same manner as in the preparation of the viscosity modifier B2a, except that the reaction temperature was changed to 60 ° C., 80 ° C., and 100 ° C. to obtain viscosity modifiers B2b to B2d. The weight average molecular weights and solid content concentrations of the viscosity modifiers B2b to B2d are as follows.

Viscosity modifier B2b: weight average molecular weight = 5500, solid content concentration = 30% by weight
Viscosity modifier B2c: weight average molecular weight = 15000, solid content concentration = 30% by weight
Viscosity modifier B2d: weight average molecular weight = 24000, solid content concentration = 30% by weight

(Viscosity modifier B3a)
A viscosity modifier B3a was prepared in the same manner as the viscosity modifier B1a except that dimethyldiethoxysilane was changed to dimethyldimethoxysilane. Viscosity modifier B3a had a weight average molecular weight of 80,000 and a solid content concentration of 30% by weight.

(Viscosity modifiers B3b to B3d)
In the same manner as in the preparation of the viscosity modifier B3a, except that the reaction temperatures were changed to 60 ° C., 80 ° C., and 100 ° C., respectively, to obtain viscosity modifiers B3b to B3d. The weight average molecular weights and solid content concentrations of the viscosity modifiers B3b to B3d are as follows.

Viscosity modifier B3b: weight average molecular weight = 12000, solid content concentration = 30% by weight
Viscosity modifier B3c: weight average molecular weight = 25000, solid content concentration = 30% by weight
Viscosity modifier B3d: weight average molecular weight = 55000, solid content concentration = 30% by weight

(Viscosity modifier B4)
Toagosei Co., Ltd., polyacrylic acid thickener powder, trade name Aron A-20P (weight average molecular weight = 5 million) was prepared as a viscosity modifier B4 for comparison.

(Viscosity modifier B5)
To a 100 ml flask equipped with a condenser, 25 g of trimethylethoxysilane, 1.5 g of oxalic acid, 10 ml of water and 20 ml of diethylene glycol diethyl ether (DEDG) were added. The solution was stirred using a semicircular mechanical stirrer, and the reaction was started at 120 ° C. with a mantle heater, but gelation occurred immediately. In other words, since trimethylethoxysilane having three alkoxy groups is used, it does not become linear, and as the molecular weight increases due to the condensation reaction, it forms a large and dense three-dimensional network structure that becomes insoluble in the solvent and causes gelation. It was. The molecular weight of the gelled product could not be measured because the gelled product did not dissolve in the solvent.

Example 1
As shown in Table 1 below, 100 parts by weight of alkoxysilane condensate A1, 30 parts by weight of viscosity modifier B1a, and 33 parts by weight of diethylene glycol (DEDG) as a solvent are kneaded to form a thin film forming composition. I got a thing.

(Examples 2 to 30 and Comparative Examples 1 to 9)
Similarly to Example 1, each alkoxysilane condensate A1, A2 or A3 and any one of viscosity modifiers B1a to B3d or B4 as shown in Table 1, Table 2, Table 3 or Table 4 below Were blended in the proportions shown in Table 1, Table 2, Table 3 or Table 4 below, and kneaded to obtain thin film forming compositions. In Comparative Example 9, an attempt was made to use the viscosity modifier B5. However, as described above, gelation occurred during the production of the viscosity modifier B5, and a thin film forming composition could not be prepared.

Evaluation The initial viscosity, which is the viscosity immediately after forming each of the thin film forming compositions, was measured at a temperature of 23 ° C. with a rotary viscometer (TVE20L manufactured by Tokimec). Further, after the composition for forming a thin film was allowed to stand at a temperature of 23 ° C. for 1 week, the viscosity at a temperature of 23 ° C. was similarly measured. The results are shown in Tables 1 to 4 below.
Moreover, the volume resistance was measured in the following ways using the composition for forming a thin film as described above.

  Measurement of volume resistance: The thin film-forming composition was coated on a substrate made of a silicon wafer by a spin coater method so as to have a thickness of 2 microns. The thin film-forming composition thus coated was dried by maintaining at a temperature of 100 for 5 minutes, and further heated at a temperature of 300 ° C. for 1 hour to form a thin film having a thickness of 2 μm. . The volume resistance of the thin film thus obtained was determined according to the method of JIS K 6911 using R8252 (electrometer) and R12704 (module) (manufactured by Advantest). The results are shown in Tables 1 to 4 below.

  As is apparent from Table 4, in Comparative Example 1, since the viscosity modifier was not added, the initial viscosity immediately after generation was as low as 12 mPa · s, but after leaving for 1 week, the viscosity was greatly increased to 150 mPa · s. Rose to.

On the other hand, in Comparative Example 2, because the polyacrylic acid-based viscosity modifier B4 was used, the viscosity after standing for one week did not increase so much, but because of the carboxylic acid-based polymer, the volume resistance of the obtained thin film was It was as low as 2.5 × 10 ⁻⁹ Ω · cm, and the insulation was not sufficient.

  On the other hand, in Examples 1 to 30, not only the initial viscosity immediately after the generation was low, but also the viscosity increase after being left at 23 ° C. for 1 week was sufficiently suppressed, and the volume resistance of the obtained thin film Therefore, it can be seen that a thin film having a uniform thickness and excellent insulating properties can be stably provided.

Claims (5)

An alkoxysilane condensate having a weight average molecular weight of 500 to 5,000,
A viscosity modifier (B) comprising a linear polysiloxane having a weight average molecular weight in the range of 10,000 to 500,000 and having a skeleton represented by the following formula (1);
A composition for forming a thin film comprising the alkoxysilane condensate (A) and a solvent for dissolving the viscosity modifier (B).

In formula (1), R _x and R _y represent hydrogen or a non-hydrolyzable organic group having 1 to 30 carbon atoms, R _x and R _y may be the same or different, and n is an integer It is. The composition for forming a thin film according to claim 1, wherein the alkoxysilane condensate (A) is an alkoxysilane condensate represented by the following formula (2).
Si (R ₁ ) _p (R ₂ ) _q (R ₃ ) _4-pq Formula (2)
In formula (2), R ₁ represents hydrogen or a non-hydrolyzable organic group having 1 to 30 carbon atoms, R ₂ represents an alkoxy group, and R ₃ represents a hydrolyzable group other than the alkoxy group. , P represents an integer of 0 to 3, q represents an integer of 1 to 4, and p + q ≦ 4. When p is 2 or 3, the plurality of R ₁ may be the same or different. When q is 2 to 4, a plurality of R ₂ may be the same or different. When p + q ≦ 2, the plurality of R ₃ may be the same or different.   The composition for thin film formation of Claim 1 or 2 mix | blended in the ratio of the said viscosity modifier (B) 5-100 weight part with respect to 100 weight part of said alkoxysilane condensates (A). Coating the thin film forming composition according to any one of claims 1 to 3 on a substrate to form a thin film forming composition layer;
And a step of drying the composition layer for forming a thin film.   The thin film formation method of Claim 4 provided with the process of heating the said composition for thin film formation in the case of the said drying or after drying.