JP2012251119A - Porous silica precursor composition and method for preparing the same, porous silica film and method for preparing the same, and semiconductor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a porous silica precursor composition for obtaining a porous silica film increased in film strength and improved in chemical liquid resistance and preparation method thereof; a porous silica film prepared by using the precursor composition and preparation method thereof; and a semiconductor element obtained by using the porous silica film.SOLUTION: This preparation method of the porous silica precursor composition using a surfactant as a template comprises: conducting polycondensation reaction of trialkoxysilane in the presence of an organic alkali catalyst; then adding a skeleton-forming material of the porous silica precursor and further conducting polycondensation reaction in the presence of an acid catalyst; or adding a skeleton-forming material of the porous silica precursor and further trialkoxysilane, and further conducting polycondensation reaction in the presence of an acid catalyst. The porous silica film prepared by using the obtained precursor composition and a semiconductor element obtained by using the porous silica film are also disclosed.

Description

  TECHNICAL FIELD The present invention relates to a porous silica precursor composition and a method for producing the same, a porous silica film and a method for producing the same, and a semiconductor device, and in particular, a porous silica precursor for obtaining a porous silica film having a large component ratio of a cage structure. The present invention relates to a composition and a method for producing the same, a porous silica film obtained using the porous silica precursor composition, a method for producing the porous silica film, and a semiconductor device using the porous silica film.

  A porous silica film is used as an interlayer insulating film or the like of a semiconductor element, and a method for producing the porous silica film is roughly divided into a CVD method and a coating method. The CVD method is a method of forming a porous silica film by adding a porogen which is an organic substance when forming a silica film by CVD and removing the porogen by heat, electron beam, UV or the like. On the other hand, in the coating method, a precursor composition (coating solution) to which a template which is an organic substance such as a surfactant is added is spin-coated to form a film, baked, and the template is removed by electron beam, UV, or the like. This is a method for obtaining a porous silica film (see, for example, Patent Document 1). In these cases, the resulting porous silica film has a problem that the film strength decreases as the amount of pores increases, and since the specific surface increases, there is an increased probability that defects in the film will appear, and chemical resistance There is also a problem of lowering. Therefore, a porous silica film having high film strength and excellent chemical solution resistance is required.

Japanese Patent Application Laid-Open No. 07-133350

  An object of the present invention is to solve the above-mentioned problems of the prior art, and by increasing the component ratio of the Si-O cage structure in the porous silica film, the film strength is increased, and chemical resistance is increased. Porous silica precursor composition and method for producing the same for obtaining an improved porous silica film, porous silica film produced using the precursor composition and method for producing the same, and obtained using the porous silica film Another object is to provide a semiconductor device.

  As a result of diligent studies to solve the above problems, the present inventors added a porous silica precursor skeleton-forming material after a hydrolysis / polycondensation reaction of a trialkoxysilane-based material using a catalyst. By using a porous silica precursor composition produced using a technique, the proportion of components of the cage structure in the porous silica film is increased, the film strength can be increased, and chemical resistance can be improved. It came to complete.

  The porous silica precursor composition of the present invention is a porous silica precursor composition containing a surfactant as a template, and a polycondensation product of trialkoxysilane and porous silica precursor obtained in the presence of an organic alkali catalyst. A polycondensation product with an acid catalyst in the presence of an acid catalyst, or a polycondensation product of a trialkoxysilane obtained in the presence of the organic alkali catalyst and a porous silica precursor skeleton formation material and It is characterized by containing a polycondensation product in the presence of an acid catalyst with alkoxysilane.

  In the porous silica precursor composition, the organic alkali catalyst is at least one selected from ammonia, choline, tetramethylammonium hydroxide, and monoethanolamine.

  In the porous silica precursor composition, the acid catalyst is an inorganic acid selected from nitric acid, hydrochloric acid, sulfuric acid, and hydrofluoric acid.

  In the porous silica precursor composition, the skeleton-forming material is at least one selected from alkoxysilanes.

  The method for producing a porous silica precursor composition of the present invention is a method for producing a porous silica precursor composition using a surfactant as a template, and after performing a polycondensation reaction of trialkoxysilane in the presence of an organic alkali catalyst, In the presence of an acid catalyst, a porous silica precursor skeleton-forming material is added to perform a polycondensation reaction, or in the presence of the acid catalyst, a porous silica precursor skeleton-forming material and further a trialkoxysilane are added. And further performing a polycondensation reaction.

  In the method for producing the porous silica precursor composition, the organic alkali catalyst is at least one selected from ammonia, choline, tetramethylammonium hydroxide, and monoethanolamine.

  In the method for producing the porous silica precursor composition, the acid catalyst is an inorganic acid selected from nitric acid, hydrochloric acid, sulfuric acid, and hydrofluoric acid.

  In the method for producing the porous silica precursor composition, the skeleton-forming material is at least one selected from alkoxysilanes.

  The porous silica film of the present invention is produced using the porous silica precursor composition or a precursor composition produced according to the production method of the porous silica precursor composition.

In the porous silica film of the present invention, the ratio of the peak height between the vicinity of 1150 cm ⁻¹ which is the peak of the Si—O cage structure and the vicinity of 1050 cm ⁻¹ which is the peak of the Si—O ladder structure in the FT-IR spectrum of the film. Is 1.0 or more.

When the ratio of the peak height between the vicinity of 1150 cm ⁻¹ that is the peak of the Si—O cage structure and the vicinity of 1050 cm ⁻¹ that is the peak of the Si—O ladder structure is less than 1.0, the desired film strength , Tend to be unable to achieve improved chemical resistance.

  The method for producing a porous silica film of the present invention is obtained by applying the porous silica precursor composition or the porous silica precursor composition produced according to the method for producing the porous silica precursor composition onto a substrate surface and firing in a vacuum atmosphere. It is characterized in that a porous silica film is produced by treating and removing the surfactant.

  The semiconductor element of the present invention is obtained by using the porous silica film produced according to the porous silica film or the method for producing the porous silica film.

  According to the present invention, a porous silica precursor composition prepared by using a technique of adding a skeleton-forming material of a porous silica precursor after proceeding polycondensation of a trialkoxysilane-based raw material using an organic alkali catalyst. By using it, the component ratio of the cage structure in the porous silica film becomes equal to or greater than the component ratio of the ladder structure, and the film strength can be increased and the chemical resistance can be improved.

2 is a spectrum diagram showing an FT-IR spectrum of the porous silica film obtained in Example 1. FIG. The spectrum figure which shows the FT-IR spectrum of the porous silica film | membrane obtained in the comparative example 1. FIG.

  According to the embodiment of the porous silica precursor composition (coating liquid) according to the present invention, the precursor composition is a precursor composition containing a surfactant as a template, and an organic alkali catalyst (for example, Trialkoxysilane (at least selected from methyltrimethoxysilane (MTMS) listed below) obtained in the presence of ammonia, choline, tetramethylammonium hydroxide, and monoethanolamine. 1 type polycondensation product and an acid catalyst (for example, at least one inorganic acid selected from nitric acid, hydrochloric acid, sulfuric acid, hydrofluoric acid, etc.), a skeleton-forming material for porous silica precursor A polycondensation product with at least one selected from the alkoxysilanes listed) or obtained in the presence of the organic alkali catalyst. It consists further contain polycondensation product in the presence of an acid catalyst with the trialkoxysilane a skeleton forming material of the polycondensation products and the porous silica precursor trialkoxysilane.

  According to the embodiment of the method for producing a porous silica precursor composition according to the present invention, this production method includes an organic alkali catalyst (for example, in a method for producing a porous silica precursor composition using a surfactant as a template). Of trialkoxysilane (at least one selected from methyltrimethoxysilane (MTMS) listed below) in the presence of ammonia, choline, tetramethylammonium hydroxide, and monoethanolamine) After performing the polycondensation reaction, the polycondensation product is subjected to the porous silica precursor in the presence of an acid catalyst (for example, at least one inorganic acid selected from nitric acid, hydrochloric acid, sulfuric acid, hydrofluoric acid, etc.). Addition of skeleton forming material (at least one selected from alkoxysilanes listed below) and further polycondensation Whether to respond, or the presence of the acid catalyst consists of performing polycondensation reaction was further added scaffolding material and further the trialkoxysilane of the porous silica precursor.

According to the embodiment of the porous silica film of the present invention, the porous silica film is obtained by using the porous silica precursor composition or the precursor composition prepared according to the method for producing the porous silica precursor composition. The peak height between the vicinity of 1150 cm ⁻¹ that is the peak of the Si—O cage structure of the FT-IR spectrum of the porous silica film and the vicinity of 1050 cm ⁻¹ that is the peak of the Si—O ladder structure. The ratio is 1.0 or more. This peak height ratio is synonymous with satisfying 50% ≦ A / (A + B) ≦ 100%, where A is the component ratio of the cage structure in the porous silica film and B is the component ratio of the ladder structure. It is. According to the examples and comparative examples described below, when the ratio between the peak height of the cage structure and the peak height of the ladder structure is 1.0 or more, that is, as the component ratio of the cage structure increases, the film strength and It can be seen that chemical resistance is improved.

  In the present invention, after proceeding hydrolysis / polycondensation reaction of trialkoxysilane-based raw material using an organic alkali catalyst, a skeleton-forming material of porous silica precursor is added to this polycondensation product, or this polycondensation By using a porous silica precursor composition prepared by adding a porous silica precursor skeleton-forming material and trialkoxysilane-based raw material to the product, the component ratio of the cage structure in the porous silica film is large. Thus, the film strength can be increased and the chemical resistance can be improved.

  The trialkoxysilane that can be used in the present invention is not particularly limited. For example, methyltrimethoxysilane (MTMS), methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane (ETES), allyltrimethoxysilane, Allyltriethoxysilane, benzyltrimethoxysilane, benzyltriethoxysilane, 1,2-bis (trimethoxysilyl) ethane, cyclohexyltrimethoxysilane, dodecyltrimethoxysilane, hexyltriethoxysilane, hexyltrimethoxysilane, octadecyltriethoxy Silane, octadecyltrimethoxysilane, n-octyltriethoxysilane, pentatriethoxysilane, triethoxyethylsilane, triethoxymethylsilane, triethoxyphenylsila , Triethoxysilane, 3- (triethoxysilyl) propyl methacrylate, triethoxyvinylsilane, trimethoxy (methyl) silane, trimethoxyphenylsilane, trimethoxy (propyl) silane, trimethoxy (p-tolyl) silane, trimethoxysilane, vinyltri And methoxysilane. Two or more of these may be used.

  The organic alkali catalyst that can be used in the present invention is not particularly limited as long as it is a catalyst capable of polycondensation (hydrolysis and polycondensation) of trialkoxysilane. For example, as described above, ammonia, choline, tetra At least one selected from methylammonium hydroxide and monoethanolamine can be used.

  The alkoxysilane that is a skeleton forming material of the porous silica precursor that can be used in the present invention is not particularly limited, and examples thereof include tetraethoxysilane (TEOS), tetramethoxysilane (TMOS), tetraisopropoxysilane, tetrabutoxysilane, and the like. Quaternary alkoxysilanes; tertiary alkoxyfluorosilanes such as trimethoxyfluorosilane, triethoxyfluorosilane, triisopropoxyfluorosilane, tributoxyfluorosilane; trimethoxymethylsilane, triethoxymethylsilane, trimethoxyethylsilane, tri Tertiary alkoxyalkylsilanes such as ethoxyethylsilane, trimethoxypropylsilane, triethoxypropylsilane; trimethoxyphenylsilane, triethoxyphenylsilane, trimethoxychlorosilane Tertiary alkoxy aryl silanes such as phenyl silane and triethoxy chlorophenyl silane; Tertiary alkoxy phenethyl silanes such as trimethoxy phenethyl silane and triethoxy phenethyl silane; Secondary alkoxy alkyl silanes such as dimethoxy dimethyl silane and diethoxy dimethyl silane; Examples include oligomers such as dimers. Two or more types may be used.

  The acid catalyst that can be used in the present invention is not particularly limited as long as it is a catalyst capable of performing a polycondensation reaction between a polycondensation product of trialkoxysilane and alkoxysilane. For example, inorganic catalysts such as hydrochloric acid, nitric acid, sulfuric acid, etc. The acid catalyst which consists of acids and organic acids, such as an acetic acid, can be mentioned, You may use it in combination of 2 or more types. However, when an organic acid is used, the effect that the residue of the organic acid remains in the obtained silica film and a silica film excellent in oxygen plasma resistance as compared with the inorganic acid can be formed is low. Therefore, it is preferable to use an inorganic acid.

  The solvent that can be used in the reaction system is not particularly limited as long as it can dissolve or disperse trialkoxysilane and alkoxysilane. For example, primary alcohol such as methanol, ethanol, 1-propanol; 2-propanol Secondary alcohols such as 2-butanol; tertiary alcohols such as tertiary butyl alcohol; acetone, acetonitrile and the like. Two or more types may be used in combination.

  As the surfactant that can be used in the present invention, a nonionic surfactant having a polyalkylene oxide structure is preferably used. Examples of the polyalkylene oxide structure include a polyethylene oxide structure, a polypropylene oxide structure, a polymethylene oxide structure, and a polybutylene oxide structure. Examples of the compound having such a polyalkylene oxide structure include polyoxyethylene polyoxypropylene block copolymer, polyoxyethylene polyoxypropylene alkyl ether, polyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyethylene alkyl ether, polyoxy Ether type compounds such as ethylene alkylphenyl ether, ether ester type compounds such as polyoxyethylene glycerin fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyethylene sorbitol fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, sucrose fatty acid ester, etc. Can be mentioned. Two or more types may be used in combination. The state of the surfactant is not limited, and it may be solid or dissolved in a solvent.

  The surfactant forms micelles in the solution and is regularly arranged. By forming a composite using these micelles as a template and removing the template in a subsequent step, a porous silica film having uniform and regular pores can be produced. By forming a porous film, for example, a film having a low dielectric constant (k) and a low refractive index is obtained.

  As described above, trialkoxysilane and organic alkali catalyst, alkoxysilane and acid catalyst, and alkoxysilane and trialkoxysilane and acid catalyst, and additives such as surfactant to be contained as necessary are dissolved or dispersed in a solvent. Then, the hydrolysis reaction and polycondensation reaction of trialkoxysilane are caused, and then the hydrolysis reaction and polycondensation reaction of the obtained polycondensation product and alkoxysilane, or the polycondensation product obtained above and alkoxysilane A porous silica precursor composition is formed by causing a hydrolysis reaction and a polycondensation reaction between silane and trialkoxysilane. These hydrolysis reactions and polycondensation reactions occur by adding water, but may be heated or stirred as necessary.

  According to the present invention, as described above, polycondensation of trialkoxysilane is carried out, and then polycondensation of this polycondensation product and alkoxysilane is carried out, or this polycondensation product, alkoxysilane and trialkoxysilane are carried out. The target porous silica precursor composition is produced by performing polycondensation with. Thus, even if polycondensation of trialkoxysilane is first carried out and polycondensation is carried out in the presence of an acid catalyst using alkoxysilane and trialkoxysilane in the next polycondensation, the target porous silica can be obtained. A precursor composition can be made. However, even if trialkoxysilane and alkoxysilane are used at the same time and a polycondensation reaction is carried out in the presence of an organic alkali catalyst or an acid catalyst, the desired desired porous silica precursor composition cannot be produced. .

  Examples of the present invention and comparative examples will be described below. The present invention is not limited to these examples. In the present invention, since the known hydrolysis reaction / polycondensation reaction is used, the trialkoxysilane, the organic alkali catalyst, the alkoxysilane, the acid catalyst, and the like to be used are those described above in addition to those used in the following examples. Those skilled in the art will understand that the present invention can be used as appropriate.

Methyltrimethoxysilane (MTMS) 0.1 mol and 10 wt% aqueous ammonia solution 0.01 mol (as ammonia) were stirred in ethanol at 25 ° C. for 3 hours to obtain a transparent and uniform solution. In this solution, tetraethoxysilane (TEOS) 0.05 mol, H ₂ O 4.25 mol, nonionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., trade name: P450, average molecular weight: 2300, OH ( CH ₂ CH ₂ O) ₁₃ (CH (CH ₃ ) CH ₂ O) ₂₀ (CH ₂ CH ₂ O) ₁₃ H) 0.01 mol, nitric acid 0.01 mol, and ethanol were added and stirred again for 3 hours, The intended porous silica precursor composition (coating solution) was obtained.

  Using this coating solution, a semiconductor Si substrate was spin-coated at 1200 rpm, and then the substrate was baked at 350 ° C. for 1 hour in a vacuum atmosphere. The temperature raising time up to 350 ° C. was 15 minutes.

  The film thickness of the porous silica film obtained as described above was 193 nm, the relative dielectric constant k was 2.1, the refractive index was 1.23, and the elastic modulus was 5.0 GPa.

FT-IR of the obtained porous silica film was measured, and this spectrum is shown in FIG. As apparent from FIG. 1, the ratio of the peak heights of the 1060 cm ^-1 is a peak of 1165 cm ^-1 and Si-O ladder structure which is the peak of the Si-O cage structures, Si-O cage structure / Si- The O ladder structure = 1.21, and the peak of the Si—O cage structure was larger. From this peak height ratio, the component ratio of the cage structure is 1.21 / (1.21 + 1.00) = 54.8%.

  The obtained porous silica film was cut into 30 mm square, and immersed in a 1 wt% KOH aqueous solution heated at 50 ° C. for 3 minutes. The film thickness variation before and after the treatment is 8 nm, which indicates that the chemical solution resistance is excellent.

MTMS 0.05 mol and 10 wt% aqueous ammonia solution 0.005 mol (as ammonia) were stirred in ethanol at 25 ° C. for 3 hours to obtain a transparent and uniform solution. To this solution, TEOS 0.05 mol, MTMS 0.05 mol, H ₂ O 4.25 mol, nonionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., trade name: P450, average molecular weight: 2300, OH ( CH ₂ CH ₂ O) ₁₃ (CH (CH ₃ ) CH ₂ O) ₂₀ (CH ₂ CH ₂ O) ₁₃ H) 0.01 mol, nitric acid 0.01 mol, and ethanol were added and stirred again for 3 hours, The intended porous silica precursor composition (coating solution) was obtained.

  Using this coating solution, a semiconductor Si substrate was spin-coated at 1200 rpm, and then the substrate was baked at 350 ° C. for 1 hour in a vacuum atmosphere. The temperature raising time up to 350 ° C. was 15 minutes.

  The film thickness of the porous silica film obtained as described above was 201 nm, the relative dielectric constant k was 2.1, the refractive index was 1.22, and the elastic modulus was 4.8 GPa.

  FT-IR of the obtained porous silica film was measured. From this spectrum, the ratio of the peak height between the peak of the Si—O cage structure and the peak of the Si—O ladder structure is Si—O cage structure / Si—O ladder structure = 1.17. The structure peak was larger. From this peak height ratio, the component ratio of the cage structure is 1.17 / (1.17 + 1.00) = 53.9%.

  The obtained porous silica film was cut into 30 mm square, and immersed in a 1 wt% KOH aqueous solution heated at 50 ° C. for 3 minutes. The film thickness variation before and after the treatment is 9 nm, which shows that the chemical solution resistance is excellent.

Ethyltriethoxysilane (ETES) 0.1 mol and 15 wt% choline aqueous solution 0.01 mol (choline conversion) were stirred in ethanol at 25 ° C. for 3 hours to obtain a transparent and uniform solution. To this solution, TEOS 0.05 mol, H ₂ O 4.25 mol, nonionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., trade name: P450, average molecular weight: 2300, OH (CH ₂ CH ₂ O) ₁₃ (CH (CH ₃ ) CH ₂ O) ₂₀ (CH ₂ CH ₂ O) ₁₃ H) 0.01 mol, nitric acid 0.01 mol, and ethanol were added, and the mixture was stirred again for 3 hours to obtain the desired porous silica precursor. A body composition (coating solution) was obtained.

  Using this coating solution, a semiconductor Si substrate was spin-coated at 1200 rpm, and then the substrate was baked at 350 ° C. for 1 hour in a vacuum atmosphere. The temperature raising time up to 350 ° C. was 15 minutes.

  The thickness of the porous silica film obtained as described above was 197 nm, the relative dielectric constant k was 2.1, the refractive index was 1.23, and the elastic modulus was 5.0 GPa.

  FT-IR of the obtained porous silica film was measured. From this spectrum, the height ratio between the peak of the Si—O cage structure and the peak of the Si—O ladder structure is Si—O cage structure / Si—O ladder structure = 1.20. The peak of was larger. From this peak height ratio, the component ratio of the cage structure is 1.20 / (1.20 + 1.00) = 54.5%.

  The obtained porous silica film was cut into 30 mm square, and immersed in a 1 wt% KOH aqueous solution heated at 50 ° C. for 3 minutes. The film thickness variation before and after the treatment is 9 nm, which shows that the chemical solution resistance is excellent.

(Comparative Example 1)
TEOS 0.05 mol, MTMS 0.1 mol, H ₂ O 4.25 mol, nonionic surfactant (trade name: P450, average molecular weight: 2300, OH (CH ₂ CH ₂ O) ₁₃ (CH (CH ₃ ) CH ₂ O) ₂₀ (CH ₂ CH ₂ O) ₁₃ H) 0.01 mol and nitric acid 0.01 mol were stirred in ethanol at 25 ° C. for 3 hours to obtain a transparent and uniform porous silica precursor composition (coating solution). Obtained.

  Using this coating solution, a semiconductor Si substrate was spin-coated at 1200 rpm, and then the substrate was baked at 350 ° C. for 1 hour in a vacuum atmosphere. The temperature raising time up to 350 ° C. was 15 minutes.

  The thickness of the porous silica film obtained as described above was 190 nm, the relative dielectric constant k was 2.1, the refractive index was 1.21, and the elastic modulus was 3.6 GPa.

  FT-IR of the obtained porous silica film was measured, and this spectrum is shown in FIG. As apparent from FIG. 2, the height ratio between the peak of the Si—O cage structure and the peak of the Si—O ladder structure is Si—O cage structure / Si—O ladder structure = 0.90. The peak of the -O ladder structure was larger. From this peak height ratio, the component ratio of the cage structure is 0.90 / (0.90 + 1.00) = 47.4%.

  When the obtained porous silica film was cut into 30 mm square and immersed in a 1 wt% KOH aqueous solution heated at 50 ° C. for 3 minutes, the film disappeared. Therefore, when the treatment time was 1 minute, the film thickness fluctuation before and after the treatment was 130 nm.

  From the above results, when MTMS and TEOS were used at the same time and an acid catalyst was used as a catalyst, a porous silica film having a cage structure component ratio less than a ladder structure component ratio was obtained. Is low and it can be seen that the chemical resistance was poor.

(Comparative Example 2)
TEOS 0.05 mol, MTMS 0.1 mol, H ₂ O 4.25 mol, nonionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., trade name: P450, average molecular weight: 2300, OH (CH ₂ CH ₂ O ) ₁₃ (CH (CH ₃ ) CH ₂ O) ₂₀ (CH ₂ CH ₂ O) ₁₃ H) 0.01 mol and 15 wt% choline aqueous solution 0.01 mol (choline conversion) were stirred in ethanol at 25 ° C. for 3 hours. Thus, a transparent and uniform porous silica precursor composition (coating solution) was obtained.

  Using this coating solution, a semiconductor Si substrate was spin-coated at 1200 rpm, and then the substrate was baked at 350 ° C. for 1 hour in a vacuum atmosphere. The temperature raising time up to 350 ° C. was 15 minutes.

  The film thickness of the porous silica film obtained as described above was 182 nm, the relative dielectric constant k was 2.1, the refractive index was 1.21, and the elastic modulus was 3.5 GPa.

  FT-IR of the obtained porous silica film was measured. From this spectrum, the height ratio between the peak of the Si—O cage structure and the peak of the Si—O ladder structure is Si—O cage / Si—O ladder = 0.85, and the peak of the Si—O ladder structure Was bigger. From this peak height ratio, the component ratio of the cage structure is 0.85 / (0.85 + 1.00) = 45.9%.

  When the obtained porous silica film was cut into 30 mm square and immersed in a 1 wt% KOH aqueous solution heated at 50 ° C. for 3 minutes, the film disappeared. Therefore, when the treatment time was 1 minute, the film thickness fluctuation before and after the treatment was 145 nm.

  From the above results, when MTMS and TEOS were used at the same time and an organic alkali catalyst was used as a catalyst, a porous silica film having a cage component ratio smaller than a ladder structure component ratio was obtained. It can be seen that the rate was low and the chemical resistance was poor.

  According to the present invention, the porous silica film can have a higher proportion of the cage structure in the film than the ladder structure, so that the film strength of the porous silica film can be increased and the chemical resistance can be improved. The present invention can be used in the industrial field of semiconductor devices.

Claims (12)

Porous silica precursor composition containing a surfactant as a template, the presence of an acid catalyst of a polyalkoxysilane polycondensation product obtained in the presence of an organic alkali catalyst and a skeleton-forming material of the porous silica precursor In the presence of an acid catalyst of a backbone formation material of a trialkoxysilane, a porous silica precursor, and a trialkoxysilane. A porous silica precursor composition comprising a polycondensation product. 2. The porous silica precursor composition according to claim 1, wherein the organic alkali catalyst is at least one selected from ammonia, choline, tetramethylammonium hydroxide, and monoethanolamine. The porous silica precursor composition according to claim 1 or 2, wherein the acid catalyst is an inorganic acid selected from nitric acid, hydrochloric acid, sulfuric acid, and hydrofluoric acid. The porous silica precursor composition according to any one of claims 1 to 3, wherein the skeleton forming material is at least one selected from alkoxysilanes. In a method for producing a porous silica precursor composition using a surfactant as a template, a polycondensation reaction of trialkoxysilane in the presence of an organic alkali catalyst and then a skeleton forming material of the porous silica precursor in the presence of an acid catalyst Or a polycondensation reaction in the presence of the acid catalyst, or a porous silica precursor skeleton-forming material and a trialkoxysilane, and a polycondensation reaction. A method for producing a precursor composition. 6. The method for producing a porous silica precursor composition according to claim 5, wherein the organic alkali catalyst is at least one selected from ammonia, choline, tetramethylammonium hydroxide, and monoethanolamine. The method for producing a porous silica precursor composition according to claim 5 or 6, wherein the acid catalyst is an inorganic acid selected from nitric acid, hydrochloric acid, sulfuric acid, and hydrofluoric acid. The method for producing a porous silica precursor composition according to any one of claims 5 to 7, wherein the skeleton-forming material is at least one selected from alkoxysilanes. The porous silica precursor produced according to the method for producing the porous silica precursor composition according to any one of claims 1 to 4 or the porous silica precursor composition according to any one of claims 5 to 8. A porous silica film produced by using a composition. The ratio of the peak height between the vicinity of 1150 cm ⁻¹ which is the peak of the Si—O cage structure and the vicinity of 1050 cm ⁻¹ which is the peak of the Si—O ladder structure in the FT-IR spectrum of the porous silica film is 1.0 or more. The porous silica film according to claim 9, wherein: The porous silica precursor produced according to the method for producing the porous silica precursor composition according to any one of claims 1 to 4 or the porous silica precursor composition according to any one of claims 5 to 8. A method for producing a porous silica film, which comprises applying the composition to a substrate surface, firing the composition in a vacuum atmosphere, and removing the surfactant to produce a porous silica film. A semiconductor element obtained by using the porous silica film according to claim 9 or 10 or the porous silica film produced according to the method for producing a porous silica film according to claim 11.

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