Method for producing silane compound polymer and method for producing semiconductor insulating film forming agent

Abstract

Disclosed are: a method for producing a silane compound polymer, the method including a step in which a trifunctional alkoxysilane compound represented by formula (a-1) R1Si(OR)3 (wherein R1 represents a hydrogen atom, an unsubstituted hydrocarbon group, or a hydrocarbon group having a substituent, each OR represents an alkoxy group, and OR may be the same as or different from each other) is hydrolyzed and polycondensed in the presence of a solvent that satisfies the requirements 1 and 2 described below; and a method for producing a semiconductor insulating film forming agent. Requirement 1: The solvent is azeotropic with water. Requirement 2: The solvent is a polyether-based solvent.

Description

Method for producing silane compound polymer and method for producing semiconductor insulating film forming agent

[0001] The present invention relates to a method for producing a silane compound polymer and a method for producing a semiconductor insulating film forming agent.

[0002] Conventionally, SiO2 has been deposited as an insulating film for semiconductor devices and the like by a vacuum process such as thermal CVD. ２ However, since vacuum processes are not suitable for forming insulating films that fill deep recesses, the SOG (Spin on Glass) method has been attracting attention in recent years.

[0003] In the SOG method, an insulating film is usually formed by applying an insulating film-forming liquid by spin coating and curing the resulting coating. For example, Patent Document 1 describes a silicon oxide film-forming composition containing a solvent, a silicon oxide-forming compound dissolved and / or dispersed in the solvent, and silicon particles dispersed in the solvent, and a method for forming a silicon oxide film using this composition.

[0004] JP 2015-18952 A

[0005] Patent Document 1 describes that the SOG method can form a relatively thick silicon oxide film in a short time, and that the use of the composition described in Patent Document 1 can form a silicon oxide film that is less susceptible to cracking. According to the examples in Patent Document 1, silicon particles are considered to be an important component for forming a thick film and preventing cracking. However, when using a composition containing silicon particles, the silicon particles must be converted into silicon oxide, which requires heat treatment under harsh conditions (in the example, 900°C for 30 minutes). Therefore, a method for forming an insulating film more efficiently has been sought.

[0006] The present invention has been made under these circumstances, and an object of the present invention is to provide a method for producing a silane compound polymer suitable as a raw material for an insulating film, and a method for producing a semiconductor insulating film forming agent.

[0007] In order to solve the above problems, the present inventors have conducted extensive research into silicon atom-containing compounds. As a result, they have found that: by using a polymer of a trifunctional silane compound such as methyltrimethoxysilane as a curable component, a cured film can be formed without excessive heating; that, while cracks may occur in cured films of silane compound polymers, silane compound polymers with few residual methoxy groups or hydroxy groups do not produce large amounts of volatile low-molecular-weight compounds as by-products upon curing, and therefore cracks are less likely to occur; and that, by carrying out the polymerization reaction of a trifunctional silane compound using a polyether solvent that forms an azeotrope with water, it is possible to produce a silane compound polymer with few residual methoxy groups or hydroxy groups while suppressing gelation, thereby completing the present invention.

[0008] Thus, according to the present invention, there are provided the following methods for producing a silane compound polymer (1) to (5) and a method for producing a semiconductor insulating film forming agent (6).

[0009] [1] A method for producing a silane compound polymer, comprising:

[0010]

[0011] [R １represents a hydrogen atom, an unsubstituted hydrocarbon group, or a hydrocarbon group having a substituent. OR represents an alkoxy group. OR may be the same or different. A method for producing a silane compound polymer, comprising a step of hydrolyzing and polycondensing a trifunctional alkoxysilane compound represented by the following formula (I) in the presence of a solvent satisfying the following requirements 1 and 2. Requirement 1: The solvent is azeotropic with water. Requirement 2: The solvent is a polyether solvent. [2] The method for producing a silane compound polymer according to [1], wherein the solvent further satisfies the following requirement 3. Requirement 3: The solvent has a boiling point of 150°C or higher. [3] The method for producing a silane compound polymer according to [1] or [2], wherein the solvent further satisfies the following requirement 4. Requirement 4: The solvent does not have a hydroxy group. [4] The method for producing a silane compound polymer according to any of [1] to [3], wherein the solvent further satisfies the following requirement 5. Requirement 5: The solvent does not have an ester bond. [5] The method for producing a silane compound polymer according to any one of [1] to [4], wherein the method is carried out with or without adding toluene to the reaction system, and the amount of toluene added is 10 mass % or less relative to the solvent. [6] A method for producing a semiconductor insulating film forming agent, comprising:

[0012]

[0013] [R １ represents a hydrogen atom, an unsubstituted hydrocarbon group, or a hydrocarbon group having a substituent. OR represents an alkoxy group. OR may be the same or different. A method for producing a semiconductor insulating film forming agent, comprising the step of hydrolyzing and polycondensing a trifunctional alkoxysilane compound represented by the following formula: in the presence of a solvent that satisfies the following requirements 1 and 2. Requirement 1: The solvent is azeotropic with water. Requirement 2: The solvent is a polyether-based solvent.

[0014] According to the present invention, there are provided a method for producing a silane compound polymer suitable as a raw material for an insulating film, and a method for producing a semiconductor insulating film forming agent.

[0015] In this specification, for preferred numerical ranges (e.g., ranges of content, etc.), the lower limit and upper limit values ​​described in stages can be independently combined. For example, the description "preferably 10 to 90, more preferably 30 to 60" can be combined with the "preferable lower limit (10)" and the "more preferable upper limit (60)" to form "10 to 60."

[0016] [Method for Producing Silane Compound Polymer] The method for producing a silane compound polymer of the present invention includes a step of hydrolyzing and polycondensing a trifunctional alkoxysilane compound represented by the above formula (a-1) in the presence of a solvent that satisfies the above requirements 1 and 2.

[0017] In the method for producing a silane compound polymer of the present invention, a trifunctional alkoxysilane compound represented by the following formula (a-1) is used as a monomer.

[0018]

[0019] In formula (a-1), R １ represents a hydrogen atom, an unsubstituted hydrocarbon group, or a substituted hydrocarbon group.

[0020] The unsubstituted hydrocarbon group preferably has 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and even more preferably 1 to 6 carbon atoms.

[0021] Examples of the unsubstituted hydrocarbon group include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, and n-decyl; alkenyl groups such as vinyl, allyl, isopropenyl, 1-butenyl, 2-butenyl, and 3-butenyl; alkynyl groups such as ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, and 3-butynyl; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl; aryl groups such as phenyl, 1-naphthyl, 2-naphthyl, tolyl, and xylyl; and groups combining these, such as benzyl and cyclohexylmethyl.

[0022] The substituted hydrocarbon group may be the unsubstituted hydrocarbon group in which one or more hydrogen atoms have been substituted with a substituent, such as an amino group, an epoxy group, an acryloyloxy group, a methacryloyloxy group, a fluorine atom, a chlorine atom, or a bromine atom.

[0023] In formula (a-1), OR represents an alkoxy group, and OR may be the same or different.

[0024] The number of carbon atoms in the alkoxy group represented by OR is preferably 1 to 6, and more preferably 1 to 3. Examples of the alkoxy group represented by OR include a methoxy group, an ethoxy group, and a propoxy group.

[0025] Specific examples of the trifunctional alkoxysilane compound represented by formula (a-1) include trimethoxysilane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, trifluoromethyltrimethoxysilane, trifluoromethyltriethoxysilane, pentafluoroethyltrimethoxysilane, pentafluoroethyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, etc. These trifunctional alkoxysilane compounds can be used alone or in combination of two or more.

[0026] In the method for producing a silane compound polymer of the present invention, in addition to the above-mentioned trifunctional alkoxysilane compound, monofunctional alkoxysilane compounds such as trimethylmethoxysilane, bifunctional alkoxysilane compounds such as dimethyldimethoxysilane, trifunctional alkoxysilane compounds other than the compound represented by formula (a-1), and tetrafunctional alkoxysilane compounds such as tetramethoxysilane may be used as monomers.

[0027] In the method for producing a silane compound polymer of the present invention, the amount of the compound represented by formula (a-1) is preferably 70 to 100 mol %, more preferably 80 to 100 mol %, and even more preferably 90 to 100 mol %, based on the total amount of monomers.

[0028] The method for producing a silane compound polymer of the present invention includes a step of hydrolyzing and polycondensing a compound represented by formula (a-1) in the presence of a solvent that satisfies the following requirements 1 and 2. Requirement 1: The solvent is azeotropic with water. Requirement 2: The solvent is a polyether-based solvent.

[0029] By using a solvent that satisfies Requirement 1, it becomes easier to obtain a silane compound polymer containing many T3 sites, as described below. A silane compound polymer containing many T3 sites does not produce large amounts of volatile low-molecular-weight compounds such as water or alcohol as by-products upon curing. Therefore, cracks are less likely to occur in the cured product of such a silane compound polymer.

[0030] In the present invention, the solvent that forms an azeotrope with water refers to a solvent that, when a mixed solvent obtained by mixing equal parts by mass of a solvent and water is placed in a distillation apparatus and the mixed solvent is heated from 23°C to (the boiling point of the solvent - 10)°C at a heating rate of 1°C / min, the proportion of water in the distillate is 10 to 90% by mass.

[0031] A solvent that satisfies requirement 2 tends to be chemically stable, and therefore, by using a solvent that satisfies requirement 2, the hydrolysis polycondensation reaction can be carried out at high temperatures.

[0032] The solvent preferably further satisfies the following requirement 3. Requirement 3: The boiling point is 150°C or higher. By using a solvent that satisfies requirement 3, the hydrolysis polycondensation reaction can be carried out at a high temperature. That is, by using a solvent that satisfies requirement 3, the temperature of the reaction system can be increased to nearly 150°C.

[0033] The solvent preferably further satisfies the following requirement 4: Requirement 4: No hydroxy group. Solvents that do not have a hydroxy group tend to be chemically stable, so by using a solvent that satisfies requirement 4, the progression of side reactions can be suppressed.

[0034] The solvent preferably further satisfies the following requirement 5: Requirement 5: No ester bond. Solvents that do not have an ester bond tend to be chemically stable, so by using a solvent that satisfies requirement 5, the progression of side reactions can be suppressed.

[0035] The solvent may be a compound represented by the following formula (b-1):

[0036] In formula (b-1), R ａ , R ｃ each independently represents a monovalent hydrocarbon group having 1 to 3 carbon atoms; R ｂ represents a divalent hydrocarbon group having 2 or 3 carbon atoms, and n is an integer of 2 to 4. ｂ may be the same or different.

[0037] Among these, dipropylene glycol dimethyl ether (boiling point 171°C) and diethylene glycol dimethyl ether (boiling point 162°C) are preferred as the solvent.

[0038] The amount of the solvent used is, for example, preferably 0.05 to 3 times, more preferably 0.1 to 1.5 times, by mass, the amount of the trifunctional alkoxysilane compound. When the reaction solution obtained by the method for producing a silane compound polymer of the present invention is used as a curable composition or a semiconductor insulating film forming agent, it is preferable to adjust the amount of the reaction solvent in consideration of the concentration of the silane compound polymer.

[0039] Furthermore, it is preferable that the solvent does not contain a low-boiling point solvent. If a low-boiling point solvent is not contained, the insulating film is less likely to volatilize when formed, and therefore a uniform, homogeneous film can be formed. A low-boiling point solvent is, for example, a solvent with a boiling point of 120°C or less. Furthermore, it is preferable that only a single solvent is used. By using only a single solvent, the effort of recovering the solvent and regenerating it by fractional distillation can be significantly reduced.

[0040] In the method for producing a silane compound polymer of the present invention, it is preferable to add water to the reaction system when carrying out the hydrolysis polycondensation reaction. The amount of water added is preferably an amount that can sufficiently hydrolyze the hydrolyzable groups contained in the monomers (e.g., "OR" in formula (a-1)). The amount of water added is preferably an amount that makes the molar ratio M of water to alkoxy groups calculated by the following formula (F1) 1.0 or more, more preferably an amount that makes 1.0 to 5.0, and even more preferably an amount that makes 1.0 to 3.0.

[0041]

[0042] In formula (F1), M Ｈ２Ｏ is the amount of water (mol number) added to the reaction system, and M ＯＲ is the total number of alkoxy groups in the monomer (total number of moles). For example, when 6.0 mol of water is added to 1.0 mol of a trifunctional alkoxysilane compound, the molar ratio M is 6.0 / 3.0 (=2.0).

[0043] When the molar ratio M is 1.0 or more, the hydrolysis reaction of the monomer can be sufficiently progressed, and a silane compound polymer having excellent curability can be easily obtained.

[0044] In the method for producing a silane compound polymer of the present invention, it is preferable to add an acid catalyst to the reaction system when carrying out the hydrolysis polycondensation reaction. Examples of the acid catalyst include inorganic acids such as phosphoric acid, hydrochloric acid, boric acid, sulfuric acid, and nitric acid; and organic acids such as formic acid, citric acid, acetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, and p-toluenesulfonic acid. Among these, at least one selected from phosphoric acid, hydrochloric acid, boric acid, sulfuric acid, formic acid, citric acid, acetic acid, and methanesulfonic acid is preferred.

[0045] The amount of the acid catalyst added is usually 0.05 to 10 mol %, preferably 0.1 to 5 mol %, based on the total amount of monomers. By adjusting the amount of the acid catalyst added, the polycondensation reaction can be allowed to proceed appropriately, and a silane compound polymer having the desired molecular weight can be obtained.

[0046] In the method for producing a silane compound polymer of the present invention, toluene may or may not be added to the reaction system during the polycondensation reaction. Toluene has traditionally been added to the reaction system as an azeotropic agent to efficiently promote the dehydration reaction, but adding toluene is undesirable from health and environmental perspectives. In the method for producing a silane compound polymer of the present invention, a solvent satisfying the above requirements 1 and 2 is used, allowing the hydrolysis polycondensation reaction to proceed sufficiently without the use of large amounts of toluene. As a result, a silane compound polymer containing many T3 sites free of hydroxyl groups or alkoxy groups is easily obtained. Furthermore, when a silane compound polymer is used as a raw material for an insulating film, the inclusion of a low-boiling point solvent such as toluene in the coating solution may volatilize the low-boiling point solvent during coating, potentially preventing the formation of a uniform, homogeneous coating film. Reducing the amount of toluene added during the production of a silane compound polymer can prevent large amounts of toluene from being mixed into the coating solution. In the method for producing a silane compound polymer of the present invention, the amount of toluene added is preferably 10% by mass or less, more preferably 5% by mass or less, relative to the solvent.

[0047] The reaction conditions for the hydrolysis polycondensation reaction are not particularly limited. The reaction temperature is usually 0 to 180° C., preferably 10 to 170° C. The reaction time is usually 30 minutes to 50 hours, preferably 1 to 24 hours.

[0048] The hydrolysis polycondensation reaction may be carried out under constant conditions from start to finish (i.e., it may have one step), or it may have multiple steps with different reaction conditions.

[0049] After the hydrolysis polycondensation reaction, the reaction solution may be used as an insulating film forming agent as it is, or a step of purifying the silane compound polymer produced by the hydrolysis polycondensation reaction may be carried out. By carrying out the purification step, a high-purity silane compound polymer can be obtained.

[0050] Examples of the silane compound polymer obtainable by the method for producing a silane compound polymer of the present invention include a silane compound polymer having a repeating unit (1) represented by the following formula (a-2) (hereinafter, sometimes referred to as "silane compound polymer (A)"):

[0051]

[0052] In formula (a-2), R １ represents the same meaning as above.

[0053] The amount of the repeating unit (1) contained in the silane compound polymer (A) is preferably 70 to 100 mol %, more preferably 80 to 100 mol %, and even more preferably 90 to 100 mol %, based on the total amount of repeating units in the silane compound polymer (A). A silane compound polymer (A) in which the amount of the repeating unit (1) is 70 mol % or more based on the total amount of repeating units in the silane compound polymer (A) tends to have an excellent balance between curability and suppression of crack generation in the cured product.

[0054] When the silane compound polymer (A) has a repeating unit other than the repeating unit (1) [repeating unit (2)], examples of the repeating unit (2) include repeating units derived from monofunctional silane compounds such as trimethylmethoxysilane, repeating units derived from bifunctional silane compounds such as dimethyldimethoxysilane, repeating units derived from trifunctional silane compounds (excluding the repeating unit (1)), and repeating units derived from tetrafunctional silane compounds such as tetramethoxysilane.

[0055] The repeating unit (1) represented by formula (a-2) is represented by the following formula (a-3):

[0056]

[0057] In formula (a-3), R １ represents the same meaning as above. １／２ indicates that the oxygen atom is shared with the adjacent repeat unit.

[0058] As shown in formula (a-3), the silane compound polymer (A) has a silicon atom to which three oxygen atoms are bonded, which is generally collectively called a T site, and other groups (R １ Examples of the T site contained in the silane compound polymer (A) include a T1 site represented by the following formula (a-4), a T2 site represented by the following formula (a-5), and a T3 site represented by the following formula (a-6):

[0059]

[0060] [R １ represents the same meaning as above. １ ~X ３ each independently represents a hydrogen atom or an alkyl group. * represents a bond to another repeating unit and is directly bonded to the silicon atom of another repeating unit.

[0061] The silane compound polymer (A) has a T3 site, and the amount of the T3 site is preferably 30 mol % or more, more preferably 30 to 91 mol %, even more preferably 32 to 65 mol %, and even more preferably 35 to 55 mol % of the total amount of the T1 site, the T2 site, and the T3 site. The T3 site is a group (-OX １ ~-OX ３ (groups represented by the formula (I))). Therefore, the amount of T3 sites is 30 mol % or more of the total amount of T sites, and even when a silane compound polymer (A) containing many T3 sites is cured, large amounts of volatile low-molecular-weight compounds such as water or alcohol are not produced as by-products. Cracks are unlikely to occur in a cured product of such a silane compound polymer (A). As described above, in the method for producing a silane compound polymer of the present invention, a solvent satisfying requirements 1 and 2 is used, so that the polycondensation reaction can proceed sufficiently while suppressing gelation, even without using a large amount of toluene as an azeotropic agent. Therefore, the method for producing a silane compound polymer of the present invention can efficiently produce a silane compound polymer containing many T3 sites.

[0062] The content ratios of the T1 site, the T2 site, and the T3 site can be determined by a conventional method by measuring the ratio of the T1 site, the T2 site, and the T3 site in the solution state of the silane compound polymer (A). ２９ The silane compound polymer (A) can be determined by measuring Si-NMR. Since the silane compound polymer (A) is soluble in various organic solvents such as ketone solvents such as acetone, aromatic hydrocarbon solvents such as benzene, sulfur-containing solvents such as dimethyl sulfoxide, ether solvents such as tetrahydrofuran, ester solvents such as ethyl acetate, halogen-containing solvents such as chloroform, and mixed solvents consisting of two or more of these, NMR of the silane compound polymer (A) in a solution state can be measured using these solvents.

[0063] The mass average molecular weight (Mw) of the silane compound polymer (A) is preferably 500 to 100,000, more preferably 1,000 to 50,000, even more preferably 1,200 to 15,000, and even more preferably 1,500 to 3,000. The molecular weight distribution (Mw / Mn) of the silane compound polymer (A) is not particularly limited, but is usually 1.0 to 10.0, preferably 1.1 to 6.0. Silane compound polymers (A) having a mass average molecular weight or molecular weight distribution (Mw / Mn) within the above ranges are suitable for use as curable components in curable compositions. The mass average molecular weight (Mw) and number average molecular weight (Mn) can be determined, for example, as standard polystyrene equivalent values ​​by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent.

[0064] The structure of the silane compound polymer (A) may be any of a ladder structure, a double-decker structure, a cage structure, a partially cleaved cage structure, a cyclic structure, and a random structure. When the silane compound polymer (A) is a copolymer, it may be any of a random copolymer, a block copolymer, a graft copolymer, an alternating copolymer, etc., but from the viewpoint of ease of production, etc., a random copolymer is preferred.

[0065] [Method for producing a semiconductor insulating film-forming agent] The method for producing a semiconductor insulating film-forming agent of the present invention comprises a step of hydrolyzing and polycondensing a trifunctional alkoxysilane compound represented by the above formula (a-1) in the presence of a solvent that satisfies the above requirements 1 and 2. That is, the method for producing a semiconductor insulating film-forming agent of the present invention involves the same operations as in the method for producing the silane compound polymer (A) described above. Therefore, the reaction solution obtained by this method, or a product obtained by concentrating or diluting this reaction solution, is the semiconductor insulating film-forming agent obtained by the method of the present invention.

[0066] The semiconductor insulating film forming agent obtained by the method of the present invention may contain additives such as curing catalysts and surfactants.

[0067] In the semiconductor insulating film forming agent obtained by the method of the present invention, the total amount of the silane compound polymer (A) and the solvent is preferably 98% by mass or more, more preferably 98 to 100% by mass, and even more preferably 99 to 100% by mass, based on the total amount of the semiconductor insulating film forming agent. A semiconductor insulating film forming agent in which the total amount of the silane compound polymer (A) and the solvent is 98% by mass or more based on the total amount of the semiconductor insulating film forming agent contains almost no reactive compounds that generate volatile low-molecular-weight compounds during the curing reaction, and therefore cracks are less likely to occur in the semiconductor insulating film.

[0068] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0069] [Azeotropy with Water] 150 g of water and 150 g of a solvent were mixed, and the resulting mixed solvent was placed in a distillation apparatus. The mixed solvent was heated from 23°C to (the boiling point of the solvent - 10)°C at a heating rate of 1°C / min. The water contents in the resulting distillate are as follows: Dipropylene glycol dimethyl ether (boiling point 171°C), the water content in the distillate was 80% by mass Diethylene glycol dimethyl ether (boiling point 162°C), the water content in the distillate was 66% by mass Propylene glycol monomethyl ether acetate (boiling point 146.4°C), the water content in the distillate was 75% by mass Ethylene glycol (boiling point 197.3°C), the water content in the distillate was 99% by mass or more

[0070] Example 1 A flask was charged with 4,000 mmol (793.16 g) of phenyltrimethoxysilane and 198.29 g of dipropylene glycol dimethyl ether (an amount sufficient to give a monomer concentration of 80% by mass). While stirring, an aqueous formic acid solution (25 mmol (1.15 g, 2.5 mol% based on the total amount of monomers) of 24,000 mmol (432.44 g) of distilled water was added dropwise to the solution over 30 minutes at 30° C. After the dropwise addition, the contents of the flask were stirred at 50° C. for 1 hour, then at 120° C. for 2 hours and at 160° C. for 2 hours. The mixture was then concentrated using an evaporator to give a silane compound polymer solution (curable composition) with a concentration of 39% by mass.

[0071] [Examples 2 to 10, Comparative Examples 1 and 2] Using the monomers and solvents shown in Table 1, a hydrolysis polycondensation reaction was carried out under the conditions of the total amount of monomers, monomer concentration, and amount of formic acid relative to the total amount of monomers shown in Table 1, to obtain solutions of silane compound polymers.

[0072] [Measurement of average molecular weight] The mass average molecular weight (Mw) of the silane compound polymer was measured using the following apparatus and conditions: Apparatus name: HLC-8220GPC manufactured by Tosoh Corporation Column: "TSK guard column SuperH-H", "TSK gel SuperHM-H", "TSK gel SuperHM-H", and "TSK gel SuperH2000" connected in sequence Solvent: tetrahydrofuran Standard substance: polystyrene Injection amount: 20 μl Measurement temperature: 40° C. Flow rate: 0.6 ml / min Detector: differential refractometer

[0073] [ ２９ Si-NMR Measurement] Apparatus: AV-500 manufactured by Bruker Biospin ２９ Si-NMR resonance frequency: 99.352 MHz Probe: 5 mmφ solution probe Measurement temperature: room temperature (25°C) Sample rotation speed: 20 kHz Measurement method: inverse gate decoupling method ２９ Si flip angle: 90° ２９ Si 90° pulse width: 8.0 μs Repetition time: 5 s Number of integrations: 9200 Observation width: 30 kHz

[0074] < ２９ Si-NMR sample preparation method> In order to shorten the relaxation time, Fe(acac) was used as a relaxation reagent. ３ Polysilsesquioxane concentration: 15% Fe(acac) ３ Concentration: 0.6% Measurement solvent: acetone Internal standard: TMS

[0075] <Pattern Processing Analysis> For each peak in the spectrum after Fourier transformation, the chemical shift was determined from the peak top position, and each peak was integrated within the following range. [Homopolymer (phenyl group)] T1: -65 to -58 ppm T2: -74 to -65 ppm T3: -83 to -74 ppm [Homopolymer (methyl group)] T1: -52 to -45 ppm T2: -60.7 to -52 ppm T3: -71.5 to -60.7 ppm [Copolymer (methyl group, 3,3,3-trifluoropropyl group)] T1: -52.5 to -45 ppm T2: -61.7 to -52.5 ppm T3: -74.5 to -61.7 ppm [Copolymer (phenyl group, methyl group)] T1: -51 to -45 ppm T2: -74 to -68.5 ppm, -60.5 to -51 ppm (sum) T3: -83 to -74 ppm, -68.5 to -60.5 ppm (sum) [Copolymer (methyl group, hydrogen atom)] The integral ratios of five peaks, namely -52 to -45 ppm (T1 of methyl unit), -60.7 to -52 ppm (T2 of methyl unit), -72 to -60.7 ppm (T3 of methyl unit and T1 of hydrogen unit), -82 to -72 ppm (T2 of hydrogen unit), and -90 to -82 ppm (T3 of hydrogen unit), were determined, and the structural ratios of T1, T2, and T3 were calculated in accordance with the composition ratio. [Copolymer (phenyl group, hydrogen atom)] The integral ratios of four peaks, namely, −63 to −59 ppm (T1 of phenyl unit), −73.5 to −63 ppm (T2 of phenyl unit and T1 of hydrogen unit), −82 to −73.5 ppm (T3 of phenyl unit and T2 of hydrogen unit), and −90 to −82 ppm, were determined, and the structural ratios of T1, T2, and T3 were calculated in accordance with the composition ratio.

[0076] [Viscosity Measurement] The viscosity of the silane compound polymer solution at 23° C. was measured using a vibration viscometer. Device name: VM-10A-L manufactured by Sekonic Corporation

[0077] [Coated Surface] When a solution of a silane compound polymer was spin-coated to form a film, the state in which a homogeneous film of uniform thickness could be formed on the silicon wafer substrate without repelling was evaluated as "A".

[0078] [Surface after drying] After forming a film by spin coating a solution of a silane compound polymer, when the film remained on the silicon wafer substrate without volatilizing when heated for 1 minute on a hot plate heated to 150°C, the state was evaluated as "A".

[0079]

[0080] The following can be seen from the Examples and Comparative Examples. In Examples 1 to 10, silane compound polymers containing many T3 sites were obtained. Solutions of these silane compound polymers have excellent coatability, so by using these solutions, it is possible to efficiently form a flat, dried coating film. On the other hand, in Comparative Examples 1 and 2, gelation occurred during the polycondensation reaction, making it impossible to examine the physical properties and coatability.

Claims

1. A method for producing a silane compound polymer, comprising: [R １ represents a hydrogen atom, an unsubstituted hydrocarbon group, or a hydrocarbon group having a substituent. OR represents an alkoxy group. OR may be the same or different. A method for producing a silane compound polymer, comprising the step of hydrolyzing and polycondensing a trifunctional alkoxysilane compound represented by the following formula: in the presence of a solvent that satisfies the following requirements 1 and 2. Requirement 1: The solvent is azeotropic with water. Requirement 2: The solvent is a polyether-based solvent.

2. The method for producing a silane compound polymer according to claim 1, wherein the solvent further satisfies the following requirement 3: the boiling point is 150°C or higher.

3. The method for producing a silane compound polymer according to claim 1, wherein the solvent further satisfies the following requirement 4: Requirement 4: The solvent does not have a hydroxy group.

4. The method for producing a silane compound polymer according to claim 1, wherein the solvent further satisfies the following requirement 5: Requirement 5: The solvent does not have an ester bond.

5. The method for producing a silane compound polymer according to claim 1, wherein the method is carried out with or without adding toluene to the reaction system, and the amount of toluene added is 10 mass % or less relative to the solvent.

6. A method for producing a semiconductor insulating film forming agent, comprising: [R １ represents a hydrogen atom, an unsubstituted hydrocarbon group, or a substituted hydrocarbon group. OR represents an alkoxy group. OR may be the same or different.] in the presence of a solvent that satisfies the following requirements 1 and 2. Requirement 1: The solvent is azeotropic with water. Requirement 2: The solvent is a polyether solvent.

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