JP2009108285A - Film-forming composition and silica-based film - Google Patents

Abstract

・・・・・（１）Ｒ¹Ｏ（ＣＨＣＨ_３ＣＨ_２Ｏ）_aＲ^２ ・・・・・（５）
【選択図】なしDisclosed are a film-forming composition that is difficult to denature during storage, and a silica-based film obtained from the composition.
A film-forming composition has a main chain in which silicon atoms and carbon atoms are alternately continuous, and is a structural unit represented by the following general formula (1): Selected from the group of compounds represented by the following general formula (5) and polycarbosilane each containing a structural unit in which H is substituted with CH ₃ and OH and OR (R represents a monovalent hydrocarbon group) And at least one organic solvent.

(1) R ¹ O (CHCH ₃ CH ₂ O) _a R ² (5)
[Selection figure] None

Description

  The present invention relates to a silica-based film-forming composition for coating containing polycarbosilane, and a silica-based film obtained from the composition.

  Polycarbosilane has attracted attention as a precursor for silicon carbide fibers and ceramic materials, and is used industrially. In particular, polycarbosilane whose main chain is a repeating structure of silicon atoms and carbon atoms is excellent in heat resistance and is widely used. Polycarbosilane is expected to be applied to optical functional materials and conductive materials.

Examples of a method for producing polycarbosilane having a main chain composed of a repeating structure of silicon atoms and carbon atoms include a method based on thermal rearrangement of poly (dimethylsilane) (Non-patent Document 1). In this method, a part of the methyl group bonded to the silicon atom in poly (dimethylsilane) is inserted into the Si—Si bond of the main chain to form a Si—C bond, and a rearranged Si—CH ₃ moiety. Replaces the Si-H bond.

While such a polycarbosilane has a hydrophobic basic skeleton, it may be required to have a hydroxyl group or an alkoxy group for improving curability. At this time, stability as a polymer in a solution is required. In some cases, the solubility was insufficient.
Journal of Materials Science, 1978, Vol. 13, p. 2569-2576 (Journal of Materials Science, 2569-2576, Vol.13, 1978)

  An object of the present invention is to provide a film-forming composition that is not easily modified during the storage period, and a silica-based film obtained from the composition.

The film forming composition according to the first aspect of the present invention comprises:
Having a main chain of alternating silicon atoms and carbon atoms, and
The structural unit represented by the following general formula (1), the structural unit represented by the following general formula (2), the structural unit represented by the following general formula (3), and the following general formula (4) Polycarbosilane containing structural units;
And at least one organic solvent selected from the group of compounds represented by the following general formula (5).

・・・・・（１）

(1)

・・・・・（２）

(2)

・・・・・（３）

(3)

・・・・・（４）

(4)

[Wherein R represents a monovalent hydrocarbon group. ]
R ¹ O (CHCH ₃ CH ₂ O) _a R ² (5)
[R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a monovalent organic group selected from CH ₃ CO—, and a represents an integer of 1 to 2. ]
In the film forming composition according to the first aspect of the present invention, the polycarbosilane may further include at least one of structural units represented by the following general formulas (6) to (10).

・・・・・（６）

(6)

・・・・・（７）

(7)

・・・・・（８）

(8)

・・・・・（９）

(9)

・・・・（１０）

(10)

In the film forming composition of the first aspect of the present invention,
In General Formula (5), one of R ¹ and R ² can be an alkyl group having 1 to 8 carbon atoms, and the other can be a hydrogen atom or CH ₃ CO—.

In the film forming composition of the first aspect of the present invention,
The weight average molecular weight of polycarbosilane is 300-300,000,
The polycarbosilane can be soluble in an organic solvent.

In the film forming composition of the first aspect of the present invention,
The organic solvent selected from the compound group represented by the general formula (5) can be contained in an amount of 50 parts by weight or more based on 100 parts by weight of the polycarbosilane.

  The silica-based film of the second aspect of the present invention is obtained by curing a coating film formed using the film forming composition of the first aspect of the present invention.

  By including the organic solvent, the film forming composition of the first aspect of the present invention can sufficiently dissolve the polycarbosilane and suppress denaturation during storage of the polycarbosilane. .

  Moreover, according to the film forming composition of the first aspect of the present invention, the structural unit represented by the general formula (1), the structural unit represented by the following general formula (2), and the general formula (3) ) And the structural unit represented by the following general formula (4), the coarse particles are few and the curability is good.

  Moreover, according to the film forming composition of the first aspect of the present invention, by including both the Si—H bond and the Si—O bond, the film can be used in an environment that is not an oxidizing atmosphere such as an inert gas atmosphere or a reduced pressure. Even when baked, the polymer can be crosslinked and cured. Moreover, since Si-Me site | part is contained, etching resistance and ashing property are favorable.

  The film-forming composition of the first aspect of the present invention can be used for ceramics, heat-resistant plastics, electronic materials, and the like. In particular, because there are few coarse particles and good curability, for example, for electronic materials (interlayer insulation films for semiconductor elements, etching stopper films, protective films such as semiconductor element surface coat films, and multilayer resists are used. It is useful as a film forming composition in an intermediate layer of a semiconductor manufacturing process, an interlayer insulating film of a multilayer wiring substrate, a protective film or insulating film for a liquid crystal display element, an optical functional material, a conductive material, and the like.

  The silica-based film of the second aspect of the present invention is homogeneous because it is obtained by curing a coating film formed using the film-forming composition of the first aspect of the present invention.

  Hereinafter, a film-forming composition according to the present invention, a method for producing the same, and a coating silica-based film containing the film-forming composition will be described.

1. Film-forming composition The film-forming composition according to the present invention contains the following polycarbosilane and an organic solvent. Polycarbosilane can be dissolved or dispersed in an organic solvent. Further, the film forming composition according to the present invention may further contain an additive as necessary.

  Details of the polycarbosilane and the organic solvent will be described below.

1.1. Polycarbosilane The polycarbosilane according to the present embodiment has a main chain in which silicon atoms and carbon atoms are alternately continuous, and is a structural unit represented by the following general formula (1): The structural unit represented by 2), the structural unit represented by the following general formula (3), and the structural unit represented by the following general formula (4) are included. That is, the polycarbosilane of the present invention comprises a main chain in which silicon atoms and carbon atoms are alternately continued, and a hydrogen atom, an oxygen atom, and a side chain containing carbon atoms bonded to the silicon atom of the main chain. Including.

  In the polycarbosilane of the present invention, the same structural unit among the structural units represented by the following general formulas (1) to (4) may be continuous, or different structural units may be present adjacent to each other. Alternatively, it may include both a portion in which the same structural unit is continuous and a portion in which different structural units are adjacent to each other.

・・・・・（１）

(1)

・・・・・（２）

(2)

・・・・・（３）

(3)

・・・・・（４）

(4)

[Wherein R represents a monovalent hydrocarbon group. ]
That is, the polycarbosilane according to the present embodiment has at least one structural unit represented by the general formulas (1) to (4). More specifically, the polycarbosilane of the present invention includes —H, —CH ₃ , —OH, and —OR in the side chain as represented by the following general formulas (1) to (4), All of these side chains are bonded to the main chain Si.

  In the general formula (4), the monovalent hydrocarbon group represented by R is not particularly limited, and examples thereof include an alkyl group, an aryl group, an alkenyl group, and an alkynyl group. When it is a group, it is preferably an alkyl group having 1 to 6 carbon atoms.

  In the present invention, the “main chain in which silicon atoms and carbon atoms are alternately continuous” has, for example, a structure represented by the following general formula (11). In the following general formula (11), the description of the side chain bonded to the main chain is omitted. Further, the numbers of silicon atoms and carbon atoms contained in the main chain are not limited thereto. In the main chain, the type of the side chain is not particularly limited, but examples of the side chain include -H, -OH, -O-Si, -OR '(where R' represents a monovalent hydrocarbon group). For example, it may be a group exemplified as R in the general formula (4), and more specifically, may be derived from an alcohol used in producing the polycarbosilane of the present invention. May be.

・・・・・（１１）
本発明のポリカルボシランにおいて、上記一般式（１）〜（４）で表される構造単位の数はそれぞれ、(１)５〜７０％、(２)３０〜８０％、(３)５〜５０％、(４)５〜３０％であることが好ましい。

(11)
In the polycarbosilane of the present invention, the number of structural units represented by the general formulas (1) to (4) is (1) 5 to 70%, (2) 30 to 80%, and (3) 5 to 5, respectively. 50% and (4) 5-30% are preferred.

  The polycarbosilane of the present invention may further include at least one of structural units represented by the following general formulas (6) to (10). In this case, in the polycarbosilane of the present invention, among the structural units represented by the following general formulas (6) to (10), the same structural unit may be continuous, or different structural units exist adjacent to each other. Or may include both a portion in which the same structural unit is continuous and a portion in which different structural units are adjacent to each other.

・・・・・（６）

(6)

・・・・・（７）

(7)

・・・・・（８）

(8)

・・・・・（９）

(9)

・・・・・（１０）

(10)

In the general formulas (7) and (8), the oxygen atom can be bonded to any one of a hydrogen atom, a silicon atom, and a carbon atom. In the general formulas (9) and (10), the carbon atom of methylene (—CH ₂ —) can be bonded to any of an oxygen atom, a silicon atom, and a carbon atom.

  The polycarbosilane of the present invention is soluble in an organic solvent, and its weight average molecular weight is preferably 300 to 300,000, and more preferably 500 to 100,000. If the weight average molecular weight is less than 300, the polymer may volatilize during firing, while if the weight average molecular weight exceeds 300,000, the polymer becomes insoluble in the solution and a coating composition cannot be obtained.

1.2. Method for Producing Polycarbosilane The method for producing polycarbosilane of the present invention has a main chain in which silicon atoms and carbon atoms are alternately continuous, and is represented by the structural unit represented by the following general formula (1) and The process includes a step of reacting a raw material polymer having the structural unit represented by the general formula (2) with an alcohol in the presence of a basic catalyst in an organic solvent and then reacting with water.

・・・・・（１）

(1)

・・・・・（２）

(2)

  Here, when it reacts with alcohol and water in presence of a basic catalyst, a coarse particle may produce | generate and gelatinize in a condensation reaction. On the other hand, according to the method for producing polycarbosilane according to the present embodiment, since it does not gel, polycarbosilane with few coarse particles can be produced.

1.2.1. Raw Material Polymer The raw material polymer used in the method for producing polycarbosilane according to the present embodiment has at least one structural unit represented by the general formulas (1) and (2). In this case, in the raw material polymer, the same structural unit among the structural units represented by the general formulas (1) and (2) may be continuous, or different structural units may be present adjacent to each other. Alternatively, it may include both a portion in which the same structural unit is continuous and a portion in which different structural units are adjacent to each other.

  The raw material polymer is at least one of a structural unit represented by the following general formula (6), a structural unit represented by the following general formula (9), and a structural unit represented by the following general formula (10). You can have one. Also in this case, the same structural unit may be continuous, or different structural units may be present adjacent to each other, or a portion where the same structural unit is continuous and a different structural unit are adjacent. It may include both existing and existing parts.

・・・・・（６）

(6)

・・・・・（９）

(9)

・・・・・（１０）

(10)

  In the production of the polycarbosilane of the present invention, the raw material polymer is not particularly limited, and examples thereof include those represented by the following general formula (12), general formula (13), and general formula (14). In the following general formulas (12) to (14), the same structural unit may be continuous, or different structural units may be present adjacent to each other, or the same structural unit may be continuous. And a portion where different structural units are present adjacent to each other may be included. This applies similarly to the general formulas (15) to (17) described later.

・・・・・（１２）
〔一般式（１２）において、ｘ，ｙはそれぞれ１以上の整数を示す。〕

(12)
[In General Formula (12), x and y each represent an integer of 1 or more. ]

・・・・・（１３）
〔一般式（１３）において、ａ，ｂはそれぞれ１以上の整数を示し、c，ｄはいずれも整数を示し、少なくとも一方が１以上である。〕

(13)
[In General Formula (13), a and b each represent an integer of 1 or more, c and d both represent an integer, and at least one is 1 or more. ]

・・・・・（１４）
〔上記一般式（１４）において、ａ，ｂはそれぞれ１以上の整数を示し、c，ｄはいずれも整数を示し、少なくとも一方が１以上である。〕

(14)
[In the general formula (14), a and b each represent an integer of 1 or more, c and d both represent an integer, and at least one is 1 or more. ]

1.2.2. Basic catalyst Examples of the basic catalyst that can be used in the production of the polycarbosilane of the present embodiment include sodium hydroxide, potassium hydroxide, lithium hydroxide, cerium hydroxide, barium hydroxide, calcium hydroxide, and pyridine. , Pyrrole, piperazine, pyrrolidine, piperidine, picoline, ammonia, methylamine, ethylamine, propylamine, butylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, monoethanolamine, Diethanolamine, dimethylmonoethanolamine, monomethyldiethanolamine, triethanolamine, diazabicycloocrane, diazabicyclononane, diazabicycloundecene, urine Examples include silicon, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, and choline. Among these, ammonia, organic amines, and ammonium hydroxides can be mentioned as preferred examples, and tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetrapropylammonium hydroxide are particularly preferable. These basic catalysts may be used alone or in combination of two or more.

  The amount of the basic catalyst used is determined by the number of silicon-hydrogen bonds contained in the raw material polycarbosilane.

1.2.3. Alcohol The alcohol that can be used in the production of the polycarbosilane of the present embodiment may be any of aliphatic (linear, cyclic) alcohols and aromatic alcohols. More specifically, methanol, ethanol, n-propanol, iso-propanol, n-butanol, tert-butanol, sec-butanol, n-propanol, ethylene glycol, propylene glycol, glycerin and the like can be mentioned.

1.2.4. Organic Solvent In the production of polycarbosilane according to the present embodiment, the following organic solvent can be used. The organic solvent used in the present invention is preferably one that can dissolve both the alcohol and water used, and the starting polymer. Or you may use an organic solvent and alcohol together by using alcohol as an organic solvent.

  Here, examples of the organic solvent include n-pentane, i-pentane, n-hexane, i-hexane, n-heptane, i-heptane, 2,2,4-trimethylpentane, n-octane, and i-octane. Aliphatic hydrocarbon solvents such as cyclohexane and methylcyclohexane; benzene, toluene, xylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, i-propylbenzene, diethylbenzene, i-butylbenzene, triethylbenzene, di- Aromatic hydrocarbon solvents such as i-propyl benzene, n-amyl naphthalene, and trimethyl benzene (when using a hydrocarbon solvent, when using water, combining a hydrocarbon solvent with another solvent) Can be used); acetone, methyl ethyl ketone Methyl-n-propylketone, methyl-n-butylketone, diethylketone, methyl-i-butylketone, methyl-n-pentylketone, ethyl-n-butylketone, methyl-n-hexylketone, di-i-butylketone, trimethylno Ketone solvents such as nanone, cyclohexanone, 2-hexanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, diacetone alcohol, acetophenone, fenchon; ethyl ether, i-propyl ether, n-butyl ether, n- Hexyl ether, 2-ethylhexyl ether, ethylene oxide, 1,2-propylene oxide, dioxolane, 4-methyldioxolane, dioxane, dimethyldioxane, ethylene glycol monomethyl ether, ethylene group Coal monoethyl ether, ethylene glycol diethyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-n-hexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, ethylene glycol dibutyl ether, diethylene glycol monomethyl ether , Diethylene glycol dimethyl ether (diglyme), diethylene glycol monoethyl ether, diethylene glycol diethyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol di-n-butyl ether, diethylene glycol mono-n-hexyl ether, ethoxytriglycol, tetraethylene glycol di-n-butyl ether , Tripro Ether solvents such as pyrene glycol monomethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran; N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, Nitrogen-containing solvents such as N-methylpropionamide and N-methylpyrrolidone; sulfur-containing solvents such as dimethyl sulfide, diethyl sulfide, thiophene, tetrahydrothiophene, dimethyl sulfoxide, sulfolane and 1,3-propane sultone; methanol, ethanol, Alcohol solvents such as n-propanol, iso-propanol, n-butanol, tert-butanol, sec-butanol, n-propanol (in this case, alcohol solvent is used as a reactant) It also has all the actions. ) And the like. These can be used alone or in combination of two or more. When used in the mixture with the above solvent, n-pentane, i-pentane, n-hexane, i-hexane, n-heptane, i-heptane, 2,2,4-trimethylpentane, n-octane, i- Aliphatic hydrocarbon solvents such as octane, cyclohexane, methylcyclohexane; benzene, toluene, xylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propyl benzene, i-propyl benzene, diethylbenzene, i-butylbenzene, triethylbenzene, di Aromatic hydrocarbon solvents such as -i-propyl benzene, n-amyl naphthalene, and trimethyl benzene can also be used.

1.2.5. Reaction with Water Specifically, in the production of polycarbosilane according to the present embodiment, a raw material polymer is reacted with an alcohol (ROH; R is an alkyl group) in an organic solvent in the presence of a basic catalyst. By converting a part of the Si—H bond into an alkoxysilane part (Si—OR) and then reacting with water, a part of the Si—OR part (in some cases, an Si—H bond may be further added). Can be converted into either a silanol moiety (Si—OH) or a Si—O—Si bond. That is, due to the reaction with water described above, a dehydration condensation reaction between the silanol sites may occur after the silanol sites are formed, whereby Si—O—Si bonds may be formed.

  Here, as a reaction with the above-mentioned water, the method of adding acidic aqueous solution in a reaction system is mentioned, for example. According to this method, it is possible to suppress further dehydration condensation of silanol sites that are expected to be generated. Although it does not specifically limit as acidic aqueous solution, For example, an organic acid or an inorganic acid can be illustrated. Examples of organic acids include acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, oxalic acid, maleic acid, methylmalonic acid, adipic acid, sebacic acid, gallic acid Acid, butyric acid, meritic acid, arachidonic acid, shikimic acid, 2-ethylhexanoic acid, oleic acid, stearic acid, linoleic acid, linolenic acid, salicylic acid, benzoic acid, p-aminobenzoic acid, p-toluenesulfonic acid, benzenesulfone Acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, formic acid, malonic acid, sulfonic acid, phthalic acid, fumaric acid, citric acid, tartaric acid, maleic anhydride, fumaric acid, itaconic acid, succinic acid, mesaconic acid, Citraconic acid, malic acid, malonic acid, hydrolyzed glutaric acid, hydrolyzed maleic anhydride Objects, and the like hydrolyzate of phthalic anhydride. Examples of inorganic acids include hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, and phosphoric acid. Of these, organic acids are preferred because they are less likely to cause polymer precipitation and gelation. Among these, compounds having a carboxyl group are more preferred, and among them, acetic acid, oxalic acid, maleic acid, formic acid, malonic acid, and phthalic acid. Particularly preferred are hydrolysates of fumaric acid, itaconic acid, succinic acid, mesaconic acid, citraconic acid, malic acid, malonic acid, glutaric acid and maleic anhydride. These may be used alone or in combination of two or more.

1.2.6. Synthesis Examples The first to third synthesis examples of the polycarbosilane according to the present embodiment are shown in the following general formula, but are not limited thereto.

  A first synthesis example of the polycarbosilane of the present invention is shown in the following general formula (A). In the first synthesis example, the case where the raw material polymer is represented by the general formula (12) will be described as an example.

・・・・・（Ａ）

(A)

  In the general formula (A), z and w are integers of 1 or more (where x> z + w is satisfied), R is as defined in the general formula (4), and x and y are As defined in general formula (12). That is, in the raw material polymer represented by the general formula (12), after a part of Si—H bond is converted into a Si—OR site by reaction with alcohol (ROH), Si—OR is reacted by reaction with water. Polycarbosilane represented by the above general formula (A) is obtained by converting a part of the site (in some cases, a part of the Si—H bond) into a Si—OH site.

  A second synthesis example of the polycarbosilane of the present invention is shown in the following general formula (B). In the second synthesis example, the case where the raw material polymer is represented by the general formula (13) will be described as an example.

・・・・・（Ｂ）

(B)

  In the general formula (B), e and f are integers of 1 or more (here, a> e + f is satisfied), g and h are integers satisfying c ≧ g + h, and R is the general formula (4 A, b, c, d are as defined in the general formula (13), and the oxygen atom can be bonded to any one of a hydrogen atom, a silicon atom, and a carbon atom. . That is, in the raw material polymer represented by the general formula (13), after a part of Si—H bond is converted into a Si—OR site by reaction with alcohol (ROH), Si—OR is reacted by reaction with water. Polycarbosilane represented by the above general formula (B) is obtained by converting a part of the site (in some cases, a part of the Si—H bond) into a Si—OH site or a Si—O—Si bond. Is obtained.

  A third synthesis example of the polycarbosilane of the present invention is shown in the following general formula (C). In the third synthesis example, the case where the raw material polymer is represented by the general formula (14) will be described as an example.

・・・・・（Ｃ）

(C)

  In the general formula (C), e and f are integers of 1 or more (where a> e + f is satisfied), g and h are integers satisfying c ≧ g + h, and R is the general formula (4 A, b, c, d are as defined in the general formula (14), and the oxygen atom can be bonded to any one of a hydrogen atom, a silicon atom, and a carbon atom. . That is, in the raw material polymer represented by the general formula (14), after a part of Si—H bond is converted to Si—OR bond by reaction with alcohol (ROH), Si—OR bond is obtained by reaction with water. Polycarbosilane represented by the above general formula (C) is obtained by converting a part of the bond (in some cases, a part of the Si-H bond) into a Si-OH site or a Si-O-Si bond. Is obtained.

2. Organic Solvent The film forming composition according to the present embodiment contains at least one organic solvent selected from the group of compounds represented by the following general formula (5).
R ¹ O (CHCH ₃ CH ₂ O) _a R ² (5)
[R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a monovalent organic group selected from CH ₃ CO—, and a represents an integer of 1 to 2. ]
By adding at least one organic solvent selected from the group of compounds represented by the following general formula (5) to the polycarbosilane produced by the production method described above, the film forming composition according to the present embodiment Is obtained.

In General Formula (5), it is preferable that ^one of R ¹ and R ² is an alkyl group having 1 to 8 carbon atoms, and the other is a hydrogen atom or CH ₃ CO—. By making R ¹ and R ² in this manner, an organic solvent having a balance between hydrophilicity and hydrophobicity with respect to polycarbosilane can be obtained.

  In the general formula (5), examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and an octyl group. , Preferably, it has 3 to 6 carbon atoms, and these alkyl groups may be chain-like or branched, and a hydrogen atom may be substituted with a fluorine atom or the like.

  Specific examples of the organic solvent represented by the general formula (5) include propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol monobutyl ether, propylene glycol mono Pentyl ether, propylene glycol monohexyl ether, propylene glycol monoheptyl ether, propylene glycol monooctyl ether, propylene glycol monoisopropyl ether, propylene glycol mono-sec-butyl ether, propylene glycol mono-tert-butyl ether, propylene glycol dimethyl ether, propylene glycol diethyl Ether, propylene glycol dipropyl Ether, propylene glycol dibutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol dipropyl ether , Dipropylene glycol dibutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether -Teracetate, dipropylene glycol monopropyl ether acetate, dipropylene glycol monobutyl ether acetate, propylene glycol diacetate, dipropylene glycol diacetate, etc., especially propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol monopentyl ether, Propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and propylene glycol monopropyl ether acetate are preferred. These can use 1 type (s) or 2 or more types simultaneously.

  The organic solvent described above has a good balance between hydrophobicity and hydrophilicity with respect to the above-described polycarbosilane, so that the silanol group possessed by the polycarbosilane can be stabilized and the polycarbosilane can be sufficiently dissolved. .

  The film-forming composition preferably contains 50 parts by weight or more of the organic solvent with respect to 100 parts by weight of the above-described polycarbosilane. By including 50 parts by weight or more, the silanol group of polycarbosilane can be sufficiently stabilized.

3. Silica film The silica film of the present invention is obtained by curing a coating film formed using the film forming composition of the present invention. More specifically, the silica-based film of the present invention can be obtained by applying the film-forming composition onto a substrate to form a coating film and curing the coating film. Here, when the silica-based composition for coating of the present invention is applied to a substrate (for example, a silicon wafer, a SiO ₂ wafer, a SiN wafer, etc.), a spin coating method, a dipping method, a roll coating method, a spray method. A coating means such as can be used. Here, the “base material” refers to a member on which the silica-based film of the present invention is formed, and its use and material are not particularly limited.

  Here, examples of the method for curing the coating film include methods such as heating and high energy ray irradiation. In the case of heating, for example, a hot plate, an oven, a furnace, or the like can be used as the heating means, and the heating atmosphere can be, for example, the air, a nitrogen atmosphere, an argon atmosphere, a vacuum, or a reduced pressure with a controlled oxygen concentration. Etc. Moreover, in order to control the curing rate of the coating film, it can be heated stepwise or an atmosphere such as nitrogen, air, oxygen, or reduced pressure can be selected as necessary.

  Moreover, you may use both a heating and high energy ray irradiation as a method of hardening the said coating film. For example, the silica-based composition for coating of the present invention is applied to a substrate to form a coating film, and the coating film is cured by heating the coating film to 30 to 450 ° C. under high energy ray irradiation. be able to.

  Since the silica-based film of the present invention is homogeneous, for example, ceramics, heat-resistant plastics, electronic materials (LSI, system LSI, DRAM, SDRAM, RDRAM, D-RDRAM and other semiconductor device interlayer insulating films and etching stoppers) Protective film such as film, surface coating film of semiconductor element, intermediate layer of semiconductor manufacturing process using multilayer resist, interlayer insulating film of multilayer wiring board, protective film and insulating film for liquid crystal display element, optical functional material, conductivity Material). In addition, the use of the silica-type film | membrane of this invention is not limited to these.

4). Examples and Comparative Examples Hereinafter, examples of the present invention will be described, but the present invention is not limited to these examples. Each evaluation in the experimental examples and the comparative examples was performed by the following methods.

4.1. Molecular Weight The weight average molecular weight (Mw) and number average molecular weight (Mn) of polycarbosilane were measured by a gel permeation chromatography (GPC) method under the following conditions.
Sample: Tetrahydrofuran was used as a solvent, and polymer 1 [g] was prepared by dissolving in 100 [cc] tetrahydrofuran.
Standard polystyrene: Standard polystyrene manufactured by US Pressure Chemical Company was used.
Apparatus: High-temperature high-speed gel permeation chromatogram (Model 150-CALC / GPC) manufactured by Waters, USA
Column: SHODEX A-80M (length: 50 cm) manufactured by Showa Denko K.K.
Measurement temperature: 40 ° C. Flow rate: 1 cc / min 4.2. NMR spectrum ¹ H NMR spectrum (500 MHz) and ²⁹ Si NMR spectrum (100 MHz) were measured using the following apparatus.
Equipment: BRUKER AVANCE 500 (Bruker)
4.3. Gas chromatography device main body: 6890N manufactured by Agilent technologies
Column: Supelco SPB-35)
Thus, the solvent composition in the solution was examined.

4.4. Example 1
20 g of a raw material polymer (trade name “Nypsi Type-S” manufactured by Nippon Carbon Co., Ltd.) was dissolved in tetrahydrofuran to 400 g, and TMAH (tetramethyl ammonium hydroxide) having a concentration of 1.0 mol / l After adding 5.0 ml of methanol solution, the reaction was heated at 50 ° C. for 3 hours. Next, after cooling this reaction liquid to room temperature, 10 ml of 2.0 mol / l oxalic acid aqueous solution was added, and reaction was stopped. Next, 200 g of diisopropyl ether and 400 g of 0.02 mol / l oxalic acid aqueous solution were added to the reaction solution, shaken and mixed, and then allowed to stand to separate into an organic phase and an aqueous phase.

  To this organic phase was added 400 g of propylene glycol monomethyl ether acetate and then concentrated to obtain 195.7 g of a polycarbosilane solution having a weight solid content of 10%.

  The physicochemical data of the polycarbosilane solution according to Example 1 are shown below.

²⁹ Si NMR (in heavy benzene) spectral data: −40 to −30 ppm (broad), −20 to 10 ppm (broad), 10 to 30 ppm (broad); the latter two peaks overlap. The integration ratio of the three peaks was approximately 2: 6: 2.

Molecular weight (GPC): Mw = 3,200, Mn = 600
IR spectral data (Ekimakuho): (corresponding to ^{Si-OH) 3670cm -1, 2950cm} -1, 2900cm -1, ( corresponding to ^{Si-OMe) 2830cm -1, 2096cm} -1, 1360cm -1, 1250cm -1 , 1030cm ^-1 , 820cm ^-1
Gas chromatography: The peak derived from propylene glycol monomethyl ether acetate was 99% or more in area ratio.

4.5. Example 2
20 g of a raw material polymer (trade name “Nypsi Type-S” manufactured by Nippon Carbon Co., Ltd.) was dissolved in tetrahydrofuran to 400 g, and TMAH (tetramethylammonium hydroxide) having a concentration of 1.0 mol / l was added thereto. After adding 5.0 ml of methanol solution, the reaction was heated at 50 ° C. for 3 hours. Next, after cooling this reaction liquid to room temperature, 10 ml of 2.0 mol / l oxalic acid aqueous solution was added, and reaction was stopped. Next, 200 g of butyl acetate and 400 g of 0.02 mol / l oxalic acid aqueous solution were added to this reaction solution, shaken and mixed, and then allowed to stand to separate into an organic phase and an aqueous phase.

  200 g of butyl acetate is added to the organic phase, and then concentrated to obtain a polycarbosilane solution having a weight solid content of 11%, and then 17.3 g of propylene glycol monopropyl ether is added to obtain a polycarbosilane having a weight solid content of 10%. A silane solution of 199.1 g was obtained.

  The physicochemical data of the polycarbosilane solution according to Example 2 are shown below.

²⁹ Si NMR (in heavy benzene) spectral data: −40 to −30 ppm (broad), −20 to 10 ppm (broad), 10 to 30 ppm (broad); the latter two peaks overlap. The integration ratio of the three peaks was approximately 2: 6: 2.

Molecular weight (GPC): Mw = 3,100, Mn = 610
IR spectral data (Ekimakuho): (corresponding to ^{Si-OH) 3670cm -1, 2950cm} -1, 2900cm -1, ( corresponding to ^{Si-OMe) 2830cm -1, 2096cm} -1, 1360cm -1, 1250cm -1 , 1030cm ^-1 , 820cm ^-1
Gas chromatography: The area ratio of butyl acetate / propylene glycol monopropyl ether was 87/13, and the peak derived from other compounds was less than 1%.

4.6. Example 3
20 g of a raw material polymer (trade name “Nypsi Type-S”, manufactured by Nippon Carbon Co., Ltd.) was dissolved in tetrahydrofuran to 400 g, and the concentration of 1.0 mol / l of TPAH (tetrapropylammonium hydroxide) After adding 5.0 ml of aqueous solution, the reaction was heated at 50 ° C. for 3 hours. Next, after cooling this reaction liquid to room temperature, 10 ml of 2.0 mol / l maleic acid aqueous solution was added, and reaction was stopped. Next, 200 g of butyl acetate and 400 g of a 0.02 mol / l maleic acid aqueous solution were added to this reaction solution, shaken and mixed, and then allowed to stand to separate into an organic phase and an aqueous phase.

  To this organic phase, 400 g of propylene glycol monobutyl ether was added and then concentrated to obtain 193.8 g of a polycarbosilane solution having a weight solid content of 10%.

  The physicochemical data of the polycarbosilane solution according to Example 3 are shown below.

²⁹ Si NMR (in heavy benzene) spectral data: −40 to −30 ppm (broad), −20 to 10 ppm (broad), 10 to 30 ppm (broad); the latter two peaks overlap. The integration ratio of the three peaks was approximately 2: 6: 2.

Molecular weight (GPC): Mw = 6,500, Mn = 1,200
IR spectral data (Ekimakuho): 3670cm ^-1 (corresponding to ^{Si-OH), 2950cm -1,} 2900cm -1, 2096cm -1, 1360cm -1, 1250cm -1, 1030cm -1, 820cm -1
Gas chromatography: The peak derived from propylene glycol monobutyl ether was 99% or more by area ratio.

4.7. Comparative Example 1
20 g of a raw material polymer (trade name “Nypsi Type-S”, manufactured by Nippon Carbon Co., Ltd.) was dissolved in tetrahydrofuran to 400 g, and TMAH (tetramethylammonium hydroxide) having a concentration of 1.0 mol / l was added thereto. After adding 5.0 ml of methanol solution, the reaction was heated at 50 ° C. for 3 hours. Next, after cooling this reaction liquid to room temperature, 10 ml of 2.0 mol / l oxalic acid aqueous solution was added, and reaction was stopped. Next, 200 g of butyl acetate and 400 g of 0.02 mol / l oxalic acid aqueous solution were added to this reaction solution, shaken and mixed, and then allowed to stand to separate into an organic phase and an aqueous phase.

  By further adding 200 g of butyl acetate to the organic phase and then concentrating, 196.2 g of a polycarbosilane solution having a weight solid content of 10% was obtained.

  The physicochemical data of the polycarbosilane solution according to Comparative Example 1 is shown below.

²⁹ Si NMR (in heavy benzene) spectral data: −40 to −30 ppm (broad), −20 to 10 ppm (broad), 10 to 30 ppm (broad); the latter two peaks overlap. The integration ratio of the three peaks was approximately 2: 6: 2.

Molecular weight (GPC): Mw = 3,100, Mn = 610
IR spectral data (Ekimakuho): (corresponding to ^{Si-OH) 3670cm -1, 2950cm} -1, 2900cm -1, ( corresponding to ^{Si-OMe) 2830cm -1, 2096cm} -1, 1360cm -1, 1250cm -1 , 1030cm ^-1 , 820cm ^-1
Gas chromatography: The peak derived from butyl acetate was 99% or more by area ratio.

4.8. Comparative Example 2
20 g of a raw material polymer (trade name “Nypsi Type-S”, manufactured by Nippon Carbon Co., Ltd.) was dissolved in tetrahydrofuran to 400 g, and the concentration of 1.0 mol / l of TPAH (tetrapropylammonium hydroxide) After adding 5.0 ml of aqueous solution, the reaction was heated at 50 ° C. for 3 hours. Next, after cooling this reaction liquid to room temperature, 10 ml of 2.0 mol / l maleic acid aqueous solution was added, and reaction was stopped. Next, 200 g of cyclohexanone and 400 g of a 0.02 mol / l maleic acid aqueous solution were added to this reaction solution, shaken and mixed, and then allowed to stand to separate into an organic phase and an aqueous phase.

  By further adding 200 g of cyclohexanone to this organic phase and then concentrating, 194.4 g of a polycarbosilane solution having a weight solid content of 10% was obtained.

  The physicochemical data of the polycarbosilane solution according to Comparative Example 1 is shown below.

²⁹ Si NMR (in heavy benzene) spectral data: −40 to −30 ppm (broad), −20 to 10 ppm (broad), 10 to 30 ppm (broad); the latter two peaks overlap. The integration ratio of the three peaks was approximately 2: 6: 2.

Molecular weight (GPC): Mw = 6,300, Mn = 1,100
IR spectral data (Ekimakuho): 3670cm ^-1 (corresponding to ^{Si-OH), 2950cm -1,} 2900cm -1, 2096cm -1, 1360cm -1, 1250cm -1, 1030cm -1, 820cm -1
Gas chromatography: The peak derived from cyclohexanone was 99% or more by area ratio.

4.9. Reference example 1
The physicochemical data of polycarbosilane (trade name “Nippi Type-S”, manufactured by Nippon Carbon Co., Ltd.) which is a raw material polymer is shown below.

²⁹ Si NMR (in heavy benzene) spectral data: −40 to −30 ppm (broad), −20 to 10 ppm (broad); the integration ratio of the two peaks was approximately 4: 6.

IR spectral data ^{(Ekimakuho): 2950cm -1, 2900cm -1,} 2096cm -1, 1360cm -1, 1250cm -1, 1030cm -1, 820cm -1
Molecular weight (GPC): Mw = 3,000, Mn = 500
4.10. Measurement and results of molecular weight The polycarbosilane solutions having a weight solid content of 10% obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were stored in a thermo-hygrostat controlled at 25 ° C. and a humidity of 40%, respectively. The results of measuring the molecular weight after 14 days and after 30 days are shown below.

  As is clear from Table 1, in Examples 1 and 3 using a propylene glycol derivative as a solvent, the molecular weight hardly changed even after long-term storage at room temperature, whereas Comparative Example 1 using other types of solvents. No. 2 showed an increase in molecular weight, and in Comparative Example 1, the solution gelled after 30 days of storage.

  Moreover, even when the main solvent was not a propylene glycol derivative like Example 2, when the said compound was used as a part solvent, it turned out that the increase in molecular weight is suppressed.

  From this, it was shown that the storage of the polycarbosilane solution in which the Si—H bond is derived from Si—OMe or Si—OH should use a solvent containing a propylene glycol derivative.

Claims (6)

Having a main chain of alternating silicon and carbon atoms, and
The structural unit represented by the following general formula (1), the structural unit represented by the following general formula (2), the structural unit represented by the following general formula (3), and the following general formula (4) Polycarbosilane containing structural units;
At least one organic solvent selected from the group of compounds represented by the following general formula (5);
A film-forming composition comprising:

(1)

(2)

(3)

(4)
[Wherein R represents a monovalent hydrocarbon group. ]

R ¹ O (CHCH ₃ CH ₂ O) _a R ² (5)
[R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a monovalent organic group selected from CH ₃ CO—, and a represents an integer of 1 to 2. ]
2. The film forming composition according to claim 1, wherein the polycarbosilane further includes at least one of structural units represented by the following general formulas (6) to (10).

(6)

(7)

(8)

(9)

(10)
In claim 1 or 2,
In the general formula (5), of R ¹ and ^{R 2,} one is an alkyl group having 1 to 8 carbon atoms, the other is a CO- hydrogen atom or _CH 3, film-forming composition. In claim 1 or 3,
The weight average molecular weight of polycarbosilane is 300-300,000,
Polycarbosilane is a film-forming composition that is soluble in an organic solvent. In claims 1 to 4,
The composition for film formation containing the organic solvent chosen from the compound group represented by General formula (5) 50 weight part or more with respect to 100 weight part of polycarbosilane.   A silica-based film obtained by curing a coating film formed using the film-forming composition according to claim 1.