KR20090031292A - Coating liquid for forming silica-based coating film, method of preparing the same and silica-based insulation film obtained from the coating liquid - Google Patents

Abstract

A coating liquid for forming a silica-based coating film is provided to ensure high film strength, excellent surface flatness, resistance to cracking, and a relatively low non-dielectric rate. A coating liquid for forming a silica-based coating film comprises silicides. The silicides are obtained by heating a dispersion having one or more organic silicon compounds and basic catalytic component-containing silica based minute particles and partly hydrolyzing the organic silicon compounds. The organic silicon compound is selected from the group consisting of alkoxy silane(RnSi(OR')4-n) and silane halide(RnSiX4-n).

Description

Coating liquid for forming a silica-based film, a method for preparing the same, and a silica-based insulating film obtained from the coating liquid TECHNICAL TECHNICAL FIELD

The present invention relates to a coating liquid for forming a silica-based coating film having high film strength, relatively low relative dielectric constant, and excellent in surface flatness, crack resistance, and the like, a preparation method thereof, and a silica coating film obtained from the coating liquid. .

In recent years, in manufacturing industries such as semiconductor devices, liquid crystal devices, sensor devices, and display devices, insulating films are formed on semiconductor substrates, on wiring layers of a multilayer wiring structure, on the surface formed of device surfaces and / or PN junction portions, on liquid crystal substrates, or the like. In many cases, a silica-based coating film is formed and used.

As the coating liquid for forming the silica-based coating film, for example, a) the general formula R _n Si (OR 'of) _4-n (formula, R, R' is an alkyl group having 1 to 8 carbon atoms, an aryl group, or Coating liquid for film formation containing the reaction product of the silica sol obtained by hydrolyzing and polycondensation of the alkoxysilane represented by a vinyl group, n is an integer of 0-3, and the partial hydrolyzate of the said alkoxysilane ( Patent Document 1) and b) silica fine particles and general formula X _n Si (OR) _4-n ( _wherein X represents H, F or an alkyl group having 1 to 8 carbon atoms, an aryl group or a vinyl group). R represents an H, or an alkyl group having 1 to 8 carbon atoms, an aryl group or a vinyl group, and n is an integer of 0 to 3.) and an alkoxysilane and / or general formula X _n SiX ' _{4 -n} ( In the formula, X represents H, F or an alkyl group having 1 to 8 carbon atoms, an aryl group or a vinyl group, X 'represents a halogen atom, and n is an integer of 0 to 3). And a coating liquid for low dielectric constant silica-based film formation (described in Patent Document 2), which contains a halogenated silane or a reactant with such a hydrolyzate.

However, the present inventors use these coating liquids and the conventionally well-known film-forming method (spin coat method or other coating method), and the test which forms a silica type film in the board | substrate or other bonding surface which comprises various apparatuses. Repeatedly, the coating having the above characteristics can be obtained, but the silica fine particles partially exist in the coating or the partial hydrolyzate and / or hydrolyzate of the silica fine particles and the alkoxysilane is present. When this is insufficient, a film having uniform and stable strength (compressive strength and tensile strength) is not necessarily obtained throughout the film, and in some cases, pinholes or cracks may occur in the film.

Accordingly, the inventors of the present invention have intensively studied for the purpose of solving such a problem. However, the present inventors have found that a coating liquid for forming a silica-based coating film described below may be used, and have completed the present invention.

[Patent Document 1] Japanese Patent Publication No. 3163579

[Patent Document 2] Japanese Patent Publication No. 3813268

The present invention is to solve the above problems, silica having a Young's modulus of 3.0GPa or more, more specifically 5.0GPa or more high film strength and relatively low relative dielectric constant, and excellent surface flatness, crack resistance, etc. An object of the present invention is to provide a coating liquid for forming a system coating film, a preparation method thereof, and a silica coating film, in particular, a silica insulating film obtained from the coating solution.

The coating liquid for forming a silica-based film according to the present invention,

At least one organosilicon compound selected from the alkoxysilane represented by the following general formula (I), the halogenated silane represented by the following general formula (II), and partial hydrolyzate thereof, and the silica-based fine particles containing a basic catalyst component And a silicon compound obtained by heating the dispersion liquid included and partially hydrolyzing and / or hydrolyzing the organosilicon compound with at least the basic catalyst component released from the silica-based fine particles.

R _n Si (OR ′) _4-n ... (Ⅰ)

R _n SiX _{4- n} . (Ⅱ)

Wherein R represents a hydrogen atom, a fluorine atom or an alkyl group having 1 to 8 carbon atoms, a fluorine-substituted alkyl group, an aryl group, a vinyl group or a phenyl group, and R 'represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms or aryl Group, a vinyl group, or a phenyl group, X represents a halogen atom, and n is an integer of 0 to 3.)

In the coating liquid for forming a silica-based film, the dispersion is preferably a water-alcohol-based dispersion containing water and an alcohol.

Moreover, it is preferable that the said dispersion liquid further contains a basic catalyst component and / or an acidic catalyst component.

Moreover, it is preferable that the said basic catalyst component is at least 1 sort (s) chosen from ammonia, ammonium hydroxide, a quaternary ammonium compound, an organic amine, and an amine coupling agent.

In addition, the acid catalyst component is preferably at least one selected from nitric acid, hydrochloric acid, acetic acid and sulfuric acid.

The silica fine particles are silica fine particles obtained by hydrolysis and polycondensation reaction of the alkoxysilane represented by the following general formula (I) in the presence of the basic catalyst component, and the basic catalyst component contained in the silica fine particles. It is preferable that the amount of is adjusted.

R _n Si (OR ′) _4-n ... (Ⅰ)

(Wherein R represents a hydrogen atom, a fluorine atom or an alkyl group having 1 to 8 carbon atoms, a fluorine-substituted alkyl group, an aryl group, a vinyl group or a phenyl group, and R 'represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms or aryl) Group, vinyl group or phenyl group, and n is an integer of 0-3.)

Moreover, it is preferable that the said silica type microparticles | fine-particles contain the said basic catalyst component in the range of 200-1100 weight ppm.

The silicon compound includes at least a portion of the reactant in which the organosilicon compound is partially hydrolyzed and / or hydrolyzed by the basic catalyst component released from the silica-based fine particles and the silica-based fine particles, and at least a part of the reactant It is preferable to couple | bond with the outer surface of the said silica type microparticles | fine-particles, and the surface in the pore.

In addition, the silicon compound is obtained by partial hydrolysis and / or hydrolysis of the organosilicon compound by the basic catalyst component and / or the acidic catalyst component contained in the dispersion and the basic catalyst component released from the silica-based fine particles. It is preferable that a reactant and the said silica-based microparticles | fine-particles are included, and at least one part of the said reactant is couple | bonded with the outer surface of the said silica-based microparticles | fine-particles, and the surface in the pore.

Moreover, it is preferable that the said silicon compound has the number average molecular weight of 500-5000 on a polystyrene conversion basis.

In addition, it is preferable that the ion concentration contained in the said coating liquid is 1.0 millimolar / liter or less.

The preparation method of the coating liquid for silica type film formation which concerns on this invention is a method of manufacturing the coating liquid for silica type film formation containing the silicon compound obtained by processing by the following process,

(a) A water-alcohol-based dispersion liquid of silica fine particles obtained by hydrolysis and polycondensation reaction of an alkoxysilane represented by the following general formula (I) in the presence of a basic catalyst component is filtered through an ultrafiltration device, A step of preparing a water-alcoholic dispersion of silica-based fine particles in which content is adjusted;

(b) at least one selected from alkoxysilanes represented by the following general formula (I), halogenated silanes represented by the following general formula (II), and partial hydrolyzates thereof in the water-alcohol dispersion liquid containing the silica-based fine particles Mixing a water dispersion containing an organosilicon compound, and

(c) heating the mixture to a temperature of 30 to 80 ° C. and partially hydrolyzing and / or hydrolyzing the organosilicon compound with at least the basic catalyst component released from the silica-based fine particles. I am doing it.

R _n Si (OR ′) _4-n ... (Ⅰ)

R _n SiX _{4- n} . (Ⅱ)

(Wherein R represents a hydrogen atom, a fluorine atom or an alkyl group having 1 to 8 carbon atoms, a fluorine-substituted alkyl group, an aryl group, a vinyl group or a phenyl group, and R 'represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms or aryl) Group, a vinyl group or a phenyl group, X represents a halogen atom, and n is an integer of 0-3.)

It is preferable that content of the basic catalyst component contained in the said silica type microparticles | fine-particles obtained at the said process (a) exists in the range of 200-1100 weight ppm.

Moreover, it is preferable to contain a basic catalyst component and / or an acidic catalyst component further in the said dispersion liquid prepared at the said process (b).

Moreover, it is preferable that the said basic catalyst component is at least 1 sort (s) chosen from ammonia, ammonium hydroxide, a quaternary ammonium compound, an organic amine, and an amine coupling agent.

The acidic catalyst component is preferably at least one selected from nitric acid, hydrochloric acid, acetic acid and sulfuric acid.

The silica-based coating according to the present invention has a high film strength and a relatively low relative dielectric constant obtained by coating and drying and firing the coating liquid for film formation on a substrate, and is excellent in surface flatness and crack resistance. It is a silica type film, It is characterized by the above-mentioned.

The silica-based coating film includes a polycondensate of a silicon compound formed by at least a part of a reactant obtained by partial hydrolysis and / or hydrolysis of the organosilicon compound bonded to the outer surface of the silica-based fine particles and the surface in the pores thereof. It is preferable.

Moreover, it is preferable that the said silica type film has the film strength of the Young's modulus of 3.0 GPa or more. Moreover, it is preferable that the said silica type film is a silica type film which has the smooth surface whose surface roughness Rms is 5.0 nm or less.

The silica coating film can be suitably used as a silica insulating film.

According to the coating liquid for forming a silica-based film according to the present invention, silica having a high Young's modulus of 3.0 GPa or more, more specifically 5.0 GPa or more, high film strength and relatively low relative dielectric constant, and excellent surface flatness, crack resistance, and the like. A cinnamon film, especially a silica type insulating film, can be formed.

Further, according to the coating liquid according to the present invention, a silica-based coating film having a smooth surface having a surface roughness (Rms) of 5.0 nm or less, in particular a silica insulating film, can be formed on a substrate even without performing a polishing treatment or the like on the surface of the coating film. Can be formed on. In addition, pinholes or the like do not appear on the surface of the obtained silica-based coating film.

In addition to the above properties, the silica-based coating film obtained by using the coating solution according to the present invention is excellent in chemical resistance such as adhesion to film-forming surfaces such as semiconductor substrates and alkali resistance, and also in terms of oxygen plasma resistance and It is equipped with the outstanding characteristic also in process suitability, such as etching workability.

Hereinafter, the coating liquid for forming a silica-based film according to the present invention, a preparation method thereof, and a silica-based film obtained by applying the coating liquid on a substrate will be specifically described.

[Coating solution for film formation]

The coating liquid for forming a silica-based film according to the present invention,

Silica microparticles | fine-particles containing the alkoxysilane represented by the following general formula (I), the halogenated silane represented by the following general formula (II), and at least 1 organosilicon compound selected from its partial hydrolyzate, and a basic catalyst component And a silicon compound obtained by heating a dispersion liquid containing and partially hydrolyzing and / or hydrolyzing the organosilicon compound with at least the basic catalyst component released from the silica-based fine particles.

R _n Si (OR ′) _4-n ... (Ⅰ)

R _n SiX _{4- n} . (Ⅱ)

(Wherein R represents a hydrogen atom, a fluorine atom or an alkyl group having 1 to 8 carbon atoms, a fluorine-substituted alkyl group, an aryl group, a vinyl group or a phenyl group, and R 'represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms or aryl) Group, a vinyl group or a phenyl group, X represents a halogen atom, and n is an integer of 0-3.)

Here, as the alkoxysilane, for example, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane, octyl Limethoxysilane, Octyltriethoxysilane, Vinyltrimethoxysilane, Vinyltriethoxysilane, Phenyltrimethoxysilane, Phenyltriethoxysilane, Trimethoxysilane, Triethoxysilane, Triisopropoxysilane, Fluorotrimethoxysilane, fluorotriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, dimethoxysilane, diethoxysilane, difluorodimethoxysilane, di Fluoro diethoxysilane, trifluoromethyltrimethoxysilane, trifluoromethyltriethoxysilane, etc. are mentioned. Among these, it is preferable to use methyl trimethoxysilane, methyl triethoxysilane, or a mixture thereof.

Examples of the halogenated silane include tetrachlorosilane, trichlorosilane, methyltrichlorosilane, methyldichlorosilane, vinyltrichlorosilane, ethyltrichlorosilane, dimethyldichlorosilane, dimethylchlorosilane, 3,3,3- Trifluoropropyltrichlorosilane, methylvinyldichlorosilane, n-propyltrichlorosilane, trimethylchlorosilane, methyl-3,3,3-trifluoropropyldichlorosilane, dimethylvinylchlorosilane, methylpropyldichlorosilane, phenyl Trichlorosilane, t-butyldimethylchlorosilane, methylphenyldichlorosilane, heptadecafluorodecyltrichlorosilane, diphenyldichlorosilane, and the like. Among these, it is preferable to use trichlorosilane, methyl trichlorosilane, or a mixture thereof.

It is preferable that the said dispersion liquid is a water-alcohol-type dispersion liquid containing water and alcohol. As alcohol used here, methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, n-butyl alcohol, etc. are mentioned, for example. Among these, it is preferable to use methyl alcohol, ethyl alcohol, or a mixture thereof.

Moreover, it is preferable that the said dispersion liquid further contains a basic catalyst component and / or an acidic catalyst component. Among these, it is preferable to use what contains the said acidic catalyst component. This is, in the initial stage, after partial hydrolysis and / or hydrolysis of the organosilicon compound in the presence of an acidic catalyst component, and then again by the effect of the action of a basic catalyst component (such as a basic catalyst component released from the silica-based fine particles). This is because a dense silica-based coating can be obtained by forming a coating using a coating solution containing a silicon compound obtained by hydrolysis and / or hydrolysis.

As said basic catalyst component, ammonia, ammonium hydroxide, a quaternary ammonium compound, an organic amine, an amine coupling agent, etc. are mentioned. Among these, it is preferable to use ammonia, ammonium hydroxide or a quaternary ammonium compound.

Moreover, nitric acid, hydrochloric acid, acetic acid, sulfuric acid, etc. are mentioned as said acidic catalyst component. Among these, it is preferable to use nitric acid or hydrochloric acid.

Moreover, as said basic catalyst component contained in the said silica type microparticles | fine-particles, ammonia, ammonium hydroxide, a quaternary ammonium compound, an organic amine, an amine coupling agent, etc. are mentioned like the above case. Among these, it is preferable that ammonia or ammonium hydroxide is contained in the said silica type microparticles | fine-particles. This is because when the dispersion liquid containing the alkoxysilane and the silica fine particles is heated, these basic catalyst components are easily released from the silica fine particles.

In addition, although the basic catalyst component contained in the said silica type microparticles | fine-particles and the basic catalyst component contained in the said dispersion liquid may be same or different, it is preferable to use the same thing as possible.

The silica fine particles are silica fine particles obtained by hydrolysis and polycondensation reaction of the alkoxysilane represented by the following general formula (I) in the presence of the basic catalyst component, and the basic catalyst component contained in the silica fine particles. It is preferable to adjust the amount of.

R _n Si (OR ′) _4-n ... (Ⅰ)

(Wherein R represents a hydrogen atom, a fluorine atom or an alkyl group having 1 to 8 carbon atoms, a fluorine-substituted alkyl group, an aryl group, a vinyl group or a phenyl group, and R 'represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms or aryl) Group, vinyl group or phenyl group, and n is an integer of 0-3.)

In this case, it is preferable to adjust content of the said basic catalyst component contained in the said silica type microparticles | fine-particles in 200-1100 weight ppm, Preferably it is 400-800 weight ppm. Here, when the content is less than 200 ppm by weight, the partial hydrolysis reaction or hydrolysis reaction of the organosilicon compound does not proceed very much in the vicinity of the outer surface of the silica-based fine particles or the surface of the pores (that is, the amount of reaction is small). Therefore, in the case where a silica-based coating film is formed using the coating liquid obtained in this way, if sufficient coating strength is not obtained and the content exceeds 1100 ppm by weight, the partial hydrolysis reaction or the hydrolysis reaction may proceed too much. Therefore, since the storage stability of the coating liquid obtained worsens, it is not preferable.

In addition, it is preferable to perform the above-mentioned adjustment by the method detailed below by filtering the water-alcohol-type dispersion liquid containing the silica type microparticles | fine-particles which consist of hydrolysis and polycondensation products of the said alkoxysilane by an ultrafiltration apparatus.

Moreover, it is preferable that the said silica type microparticles | fine-particles exist in the range of 5-500 nm. Here, if the average particle diameter is less than 5 nm, the effect as a filler cannot be sufficiently exhibited. Therefore, there is a problem in terms of improving the strength of the film, and if the average particle diameter exceeds 500 nm, a uniform dispersion state is obtained. As it becomes difficult to save, it is not preferable.

In addition, the organosilicon compound may be partially hydrolyzed in advance of the alkoxysilane and / or the halogenated silane, and then mixed with the water-alcohol dispersion of the silica-based fine particles containing the basic catalyst component and further hydrolyzed.

In this case, partial hydrolysis of the alkoxysilane and / or halogenated silane is preferably carried out in the presence of the acidic catalyst component. This is partially hydrolyzed beforehand in the presence of an acidic catalyst component in the presence of an acidic catalyst component, and then further hydrolyzed by the effect of the action of a basic catalyst component (basic catalyst component released from the silica-based fine particles) as in the above case. This is because a dense silica-based coating film can be obtained by forming a coating film using a coating liquid containing a silicon compound obtained by the above-described method.

The content ratio of the above silica-based fine particles and the organosilicon compound is, when the display on the weight of the silica-based fine particles A, and also shows the weight of (SiO ₂ equivalent basis) of the silicon compound with B, the weight ratio (A / B) is preferably in the range of 1/9 to 9/1, preferably 4/6 to 6/4. Here, when the said weight ratio is less than 1/9, the crack resistance of the finally obtained film will worsen, and when the said weight ratio exceeds 9/1, since the dielectric constant of the said film will rise, it is unpreferable.

The silicon compound obtained in this way includes the silica-based fine particles and a reactant in which the organosilicon compound is partially hydrolyzed and / or hydrolyzed by at least the basic catalyst component released from the silica-based fine particles. At least a portion of the reactant is bound to the outer surface of the silica-based fine particles and the surface in the pores thereof. This is because the basic catalyst component released from the silica-based fine particles may partially hydrolyze and / or hydrolyze the organosilicon compound in the vicinity of the outer surface of the silica-based fine particles or the surface in the pores thereof. It is considered that the bonding with the silica fine particles is performed sufficiently.

When using the thing containing a basic catalyst component and / or an acidic catalyst component in the said dispersion liquid, by the said basic catalyst component contained in the said dispersion liquid, and / or the said basic catalyst component discharge | released from the said silica type microparticles | fine-particles, A silicon compound in which the organosilicon compound comprises a partially hydrolyzed and / or hydrolyzed reactant and the silica-based fine particles, and at least a portion of the reactant is bonded to the outer surface of the silica-based fine particles and the surface in the pores thereof. You can get it.

Moreover, it is preferable that the said silicon compound obtained in this way has a number average molecular weight of 500-5000, Preferably 800-3000 on a polystyrene conversion basis. When this number average molecular weight exists in the said range, the coating liquid for silica type film formation which shows the outstanding time-lapse stability and favorable coatability can be provided.

In addition, although the water-alcohol dispersion liquid containing the said silicon compound obtained in this way may be used as a coating liquid for silica type film formation in the state as it is, the water and alcohol component contained in the said dispersion liquid are a conventionally well-known method, an example For example, it is preferable to use by substituting a solvent with at least one organic solvent selected from propylene glycol monopropyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether acetate, etc. using a distillation method by a rotary evaporator. .

By performing this solvent substitution, water and alcohol contained in the water-alcohol dispersion liquid, and alcohols produced by hydrolysis of the alkoxysilane and the like are separated and removed. On the other hand, if said operation is performed using a rotary evaporator, although said solvent substitution can be performed almost completely, in this invention, it does not necessarily need to perform this completely.

The amount of the silicon compound contained in the coating liquid obtained in this manner varies according to its intended use, when the display is a silicon compound as a SiO _2, 2~50% by weight based on the weight of the coating solution, preferably from 10 to It is preferable to adjust so that it may become 40 weight% of a range. Here, when this content exceeds 50 weight%, the time-lapse stability of the said coating liquid will worsen, and if it is less than 2 weight%, it will become difficult to form a uniform film on a board | substrate.

Moreover, in this invention, surfactant, a polysilicon resin, etc. as a leveling agent may be added to the said liquid composition. Examples of the surfactants include silicone-based surfactants such as polyoxyalkylene dimethylpolysiloxane, fluorine-based surfactants such as perfluoro alkyl carbonate and perfluoro alkyl ethylene oxide adducts, and the like. And polyether modified silicone resins, amino modified silicone resins, epoxy modified silicone resins, alkoxy modified resins, and the like. Among these, it is preferable to use polysilicon resin.

In addition, the ion concentration contained in the coating liquid for forming a silica-based coating film is preferably 1.0 millimoles / liter or less, preferably 0.6 millimoles / liter or less. Here, when an ion concentration exceeds 1.0 millimoles / liter, when a film is formed using the said coating liquid, voids, pinholes, etc. may arise in a coating due to the ion contained in the said coating liquid, Not desirable

[Preparation method of coating liquid for film formation]

Next, the preparation method of the coating liquid for silica type film formation which concerns on this invention is described as follows.

The preparation method of the coating liquid which concerns on this invention is a method of manufacturing the coating liquid for silica type film formation containing the silicon compound obtained by the following processes,

(a) A water-alcohol-based dispersion liquid of silica fine particles obtained by hydrolysis and polycondensation reaction of an alkoxysilane represented by the following general formula (I) in the presence of a basic catalyst component is filtered through an ultrafiltration device, A step of preparing a water-alcoholic dispersion of silica-based fine particles in which content is adjusted;

(b) at least one selected from alkoxysilanes represented by the following general formula (I), halogenated silanes represented by the following general formula (II), and partial hydrolyzates thereof in the water-alcohol-based dispersion liquid containing the silica-based fine particles Mixing a water dispersion liquid containing an organosilicon compound of

(c) heating the mixed solution to a temperature of 30 to 80 ° C., and partially hydrolyzing and / or hydrolyzing the organosilicon compound with at least the basic catalyst component released from the silica-based fine particles.

R _n Si (OR ′) _4-n ... (Ⅰ)

R _n SiX _{4- n} . (Ⅱ)

(Wherein R represents a hydrogen atom, a fluorine atom or an alkyl group having 1 to 8 carbon atoms, a fluorine-substituted alkyl group, an aryl group, a vinyl group or a phenyl group, and R 'represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms or aryl) Group, a vinyl group or a phenyl group, X represents a halogen atom, and n is an integer of 0-3.)

When it demonstrates concretely about said each process, it is as follows.

Process (a)

In this step, the alkoxysilane is hydrolyzed and polycondensed in the presence of the basic catalyst component to prepare a water-alcoholic dispersion of the silica fine particles. However, a conventionally known method can be employed for the preparation method. have. That is, 1) adding an aqueous solution of a basic catalyst component (e.g., ammonia) to the water-alcohol dispersion containing the alkoxysilane, and then ripening the obtained hydrolysis and condensate; 2) obtained in 1). Silica-based fine particles are hydrothermally treated in a pressure vessel such as an autoclave to further mature. However, it is preferable that the average particle diameter of the said silica type microparticles | fine-particles exists in the range of 5-500 nm.

However, in the method of the present invention, it is necessary to adjust the content of the basic catalyst component contained in the silica-based fine particles. The method is specifically described as follows. However, the method of the present invention is not limited to the method described herein.

(1) First, the water-alcohol-based dispersion liquid containing the silica-based fine particles obtained by the above method was filtered through an ultrafiltration apparatus and concentrated until its capacity was about one half to about one fifth. The unreacted substance, intermediate reactant, etc. of the said alkoxysilane contained in a dispersion liquid are removed. In this case, a part of water, alcohol, and basic catalyst component (for example, ammonia) contained in the dispersion is removed.

(2) Then, water (alcohol) dispersion liquid obtained in the above (1) was added with about 1 to 3 times the capacity of pure water (using a temperature of 5 to 25 ° C and the same as follows), followed by stirring. In addition, the ultrafiltration device is concentrated until its capacity is about one half, and a part of the basic catalyst component contained in the dispersion is removed. If necessary, pure water having the same capacity as that of the obtained water-alcoholic dispersion is added and stirred, and then the same operation is repeated through an ultrafiltration device. By repeating this operation, since the basic catalyst component is gradually released into the dispersion liquid in the silica-based fine particles, the content of the basic catalyst component contained in the silica-based fine particles can be adjusted. The recovery of the operation carried out here depends on the basic catalyst component contained in the silica fine particles, the content thereof, the properties of the silica fine particles and the like, but is preferably performed 2 to 5 times.

(3) Next, to the water-alcohol-based dispersion liquid (alcohol concentration is low) obtained in the above (1) or (2), the same capacity of alcohol (using a temperature of 5 to 25 ° C, is the same below). After addition and stirring, the solution was concentrated by ultrafiltration to a capacity of about 1/2, and solvent and water and alcohol contained in the dispersion were substituted. Further, if necessary, the obtained water-alcohol-based dispersion liquid and the same amount of alcohol are added and stirred, and then the same operation is repeated by an ultrafiltration device. By repeating this operation about 2-4 times, the alcohol concentration contained in the said water-alcohol dispersion liquid is adjusted to about 60 to 90 weight%. Thereby, the water-alcohol dispersion liquid suitable for mixing with the water dispersion liquid of the said organosilicon compound can be obtained. Moreover, it is preferable to adjust the density | concentration of the said silica type microparticles | fine-particles contained in this water- alcohol dispersion liquid to about 5-20 weight%.

Thereby, the water-alcohol-type dispersion liquid containing silica type microparticles | fine-particles adjusted in the range of 200-1100 weight ppm of said basic catalyst component can be obtained.

However, since the required amount of the basic catalyst component is different depending on the kind and amount of the organosilicon compound used in the step (b) at a later stage or the kind and content of the catalyst component contained in the dispersion obtained by mixing these, these It is preferable to adjust content of the basic catalyst component contained in the said silica type microparticles | fine-particles in the said range in consideration of conditions.

On the other hand, this water-alcohol-based dispersion contains the basic catalyst component used in the hydrolysis and polycondensation reaction. That is, the dispersion contains a basic catalyst component which is not removed in the ultrafiltration operation or a basic catalyst component partially released from the silica-based fine particles after the end of the operation, but is carried out in the subsequent step (b). Since it can use for a partial hydrolysis and / or a hydrolysis reaction, you may include as it is.

The alkoxysilane used in this step can be used without particular limitation as long as the silica fine particles can be obtained, but ethyl silicate, methyl silicate or the like is preferably used.

As the basic catalyst component, at least one selected from ammonia, ammonium hydroxide, quaternary ammonium compound, organic amine and amine coupling agent can be used, but ammonia or ammonium hydroxide is preferred among these. .

Moreover, as said alcohol, at least 1 sort (s) chosen from methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, n-butyl alcohol can be used, Among these, it is preferable to use methyl alcohol or ethyl alcohol.

Process (b)

In this step, the water-alcohol dispersion liquid containing the silica-based fine particles obtained in the step (a), the alkoxysilane represented by the following general formula (I), the halogenated silane represented by the following general formula (II) and its partial valence A water dispersion liquid containing at least one organosilicon compound selected from the decomposed products is mixed. Thereby, the water-alcohol dispersion liquid containing the said silica type microparticles | fine-particles, the said organosilicon compound, etc. can be obtained.

Here, as mentioned above, the alkoxysilane and / or halogenated silane may be mixed after partial hydrolysis in the presence of an acidic catalyst component, for example.

The mixing ratio of the silica-based fine particles and the organosilicon compound is the weight ratio (A /) when the weight of the silica-based fine particles is expressed by A, and the weight (based on SiO ₂ conversion) of the silicon compound is expressed by B. It is preferable that B) is 1 / 9-9 / 1, Preferably it exists in the range of 4 / 6-66 / 4. The reason is as described above.

In this step, the dispersion can further contain a basic catalyst component and / or an acidic catalyst component.

As mentioned above, the water-alcohol-type dispersion liquid obtained at the said process (a) contains the basic catalyst component in many cases. However, when the amount of the basic catalyst component contained in the silica fine particles obtained in the step (a) is smaller than the desired value, the basic catalyst component may be added to the dispersion from the outside. In such a case, there are the following cases.

(1) This is a case where a water-alcoholic dispersion containing silica-based fine particles further hydrolyzed by hydrothermal treatment and polycondensation reaction of the alkoxysilane in a pressure vessel such as an autoclave is used. Since the obtained silica-based microparticles | fine-particles become a comparatively dense structure, the basic catalyst component contained in the said silica-based microparticles may be slightly small.

(2) When ultrafiltration of a water-alcohol-based dispersion liquid containing silica-based fine particles obtained by hydrolysis and polycondensation of the alkoxysilane, or hydrothermally treating them in a pressure vessel such as an autoclave and further aged silica-based fine particles, It is a case where the content of the basic catalyst component contained in the silica type microparticles | fine-particles or water-alcohol dispersion liquid obtained by performing wrong operation (for example, excessive operation frequency | count etc.) falls below a desired value. In such a case, the said Sometimes it is necessary to supplement the basic catalyst components from the outside.

In addition, in order to form a silica-based film having a high film strength, as described above, it is preferable to add an acidic catalyst component to the water-alcohol-based dispersion. This is further caused by the effect of the action of a basic catalyst component (such as a basic catalyst component released from the silica-based fine particles) after partial hydrolysis and / or hydrolysis of the organosilicon compound in the presence of an acidic catalyst component in an initial stage. This is because a dense silica-based coating can be obtained by forming a coating using a coating liquid containing a silicon compound obtained by partial hydrolysis and / or hydrolysis.

In addition, as said basic catalyst component and the said acidic catalyst component, it can select and use from said thing.

Process (c)

In this step, the organosilicon compound is partially hydrolyzed by the basic catalyst component which is heated at a temperature of 30 to 80 ° C., that is, the water-alcohol dispersion liquid obtained in the step (b), and at least released from the silica-based fine particles. Degradation and / or hydrolysis.

Although the mixed liquid which consists of the said water-alcohol dispersion liquid changes with the basic catalyst component contained in the said silica type microparticles | fine-particles, it is preferable to heat at 30-80 degreeC, Preferably it is 40-70 degreeC. Here, when the said temperature is less than 30 degreeC, since the release rate of the basic catalyst component contained in the said silica type microparticles | fine-particles is slow, the time for partial hydrolysis and / or hydrolysis of the said organosilicon compound becomes long, and also the said temperature When the temperature exceeds 80 ° C, since the diffusion of the basic catalyst component contained in the silica-based fine particles occurs rapidly or rapidly, the stability of the dispersion becomes poor, which is not preferable.

Thus, although the said basic catalyst component contained in the said silica type microparticles | fine-particles is gradually discharged | released from the said silica type microparticles | fine-particles by heating the said mixed liquid, you may perform said heating operation step by step as needed.

As a result, the organosilicon compound is partially hydrolyzed and / or hydrolyzed in the vicinity of the outer surface of the silica-based fine particles and the surface within the pores by the basic catalyst component released from the silica-based fine particles. A silicon compound sufficiently bonded to the silica fine particles can be obtained. In this case, the organosilicon compound is partially hydrolyzed and / or hydrolyzed by the basic catalyst component contained in the mixed solution, but in the method of the present invention, at least by the basic catalyst component released from the silica-based fine particles. Partial hydrolysis and / or hydrolysis is important.

The water-alcohol dispersion obtained in this way is a propylene glycol monopropyl ether or propylene glycol mono containing water and an alcohol component contained in the dispersion using a conventionally known method, for example, a distillation method using a rotary evaporator. At least one organic solvent selected from methyl ether, propylene glycol monomethyl ether acetate and the like may be substituted with a solvent.

When the specific example (example using propylene glycol monopropyl ether (PGP) as an organic solvent for solvent substitution) is shown, it is as follows. However, the present invention is not limited to the method described here.

(Iii) The water-alcohol dispersion obtained above is placed in a flask of a rotary evaporator, and propylene glycol monopropyl ether is placed in the flask.

(Ii) Next, the rotary evaporator is driven and under reduced pressure conditions of -0.05 to -0.1 MPa, preferably -0.08 to -0.1 MPa under a temperature condition of 50 to 90 ° C, preferably 60 to 80 ° C. The flask is rotated at a speed of 30 to 120 rpm, preferably 60 to 90 rpm. Then, since water and alcohol contained in the water-alcohol dispersion are evaporated, it is cooled and discharged out of the system.

(Iii) By carrying out the above operation (ii) for a necessary time, the coating liquid for forming a silica-based film in which the water and the alcohol and the propylene glycol monopropyl ether are solvent-substituted can be obtained.

In addition, by this, the quantity of the silicon compound contained in the said coating liquid for silica type film formation can be adjusted to said desired range. Here, the silicon compound content of water varies according to its intended use, when this display the silicon compound to SiO _2, 2~50% by weight, relative to the weight of the coating solution, preferably in the range of 10 to 40% by weight It is desirable to adjust so that

[Method of Forming Silica-based Coating]

In the present invention, in order to form a silica-based coating film by using the coating liquid for forming a silica-based film, a conventionally known method can be adopted. Moreover, as this conventionally well-known method, there exist the following.

(1) The method of apply | coating the said coating liquid for silica type film formation on a board | substrate, and heat-processing the said board | substrate at the temperature of 80-350 degreeC, and baking further at the temperature of 340-450 degreeC higher than the said heating temperature.

(2) A method in which the coating solution for forming a silica-based coating film is applied onto a substrate, followed by heating the substrate at a temperature of 80 to 350 ° C., followed by further irradiation with an electron beam, ultraviolet light or microwave.

That is, in this invention, it is preferable to select a suitable method from such a conventionally well-known method according to the property of the said coating liquid for silica type film formation, and its use.

Although the said film formation method is demonstrated concretely below using the said (1) method as an example, this invention is not limited to this.

Coating process

Generally, in order to apply | coat the coating liquid for film formation on a board | substrate, the coating methods, such as a spin coat method, the dip coat method, the roll coat method, the slit coater method, the transfer method, are employ | adopted. The coating liquid for forming a silica-based film can be applied using a known method. Among these, in the case of coating the coating liquid for forming a film on a semiconductor substrate or the like, the spin coating method is suitable, and is excellent in the uniformity of the coating film thickness, low oscillation property, and the like. Therefore, in this invention, although it is preferable to employ | adopt the coating method by this spin coating method, when apply | coating on a semiconductor substrate with a large diameter, etc., you may employ | adopt a transfer method.

On the other hand, in the present invention, the term "coating a coating liquid on a substrate" means that the coating liquid is not only directly applied onto a substrate such as a silicon wafer, but also a protective film for semiconductor processing or the like formed on the substrate. It also includes applying to the top of the film.

Heating process

The film coated on the substrate in this manner is heat treated at a temperature of 80 to 350 ° C. Here, when this heat treatment is performed at a temperature exceeding 350 ° C., the organic solvent contained in the coating film may evaporate rapidly, thereby forming pores and voids having a relatively large diameter in the coating film. Strength may fall. Therefore, it is preferable to perform this heat processing stepping up the temperature in the range of 80-350 degreeC as needed. For example, the method of heat-processing at step temperature, such as 1 minute at the temperature of 150 degreeC, 1 minute at the temperature of 250 degreeC, and 1 minute at the temperature of 350 degreeC, etc. is mentioned. Moreover, when this heat processing is performed at a temperature below 80 degreeC, most of the organic solvent contained in the said coating film may remain in the film as it is, without evaporating, As a result, the objective of this heat processing can be achieved. In addition, the film thickness of the formed film may be uneven.

Moreover, although this heat processing changes with film thickness etc. of a film, it is preferable to carry out over 1 to 10 minutes, Preferably it is 2 to 5 minutes.

In addition, this heat treatment can be performed in a nitrogen gas atmosphere or an air atmosphere as an inert gas. Since this treatment is performed for a short time under relatively low temperature conditions of 350 ° C. or less, even if the heat treatment is performed in an air atmosphere containing a relatively large amount of oxygen, damage caused by metal oxidation or the like on the metal wiring or the like disposed on the semiconductor substrate is caused. Because it does not give. In addition, since a small amount of oxygen is more likely to enter the film, a silica-based film formed by cross-linking of Si-O-Si bonds is formed in the process of subsequent firing, thereby improving hygroscopicity (hydrophobicity) and high film strength. It becomes easy to form the silica type coating film which has.

In this way, when the heat treatment is applied, the organic solvent or the like contained in the coating film evaporates and escapes, and on the other hand, the polymerization of the silica-based coating-forming component as a solid component proceeds to cure and aggregates in the heating process. Melt viscosity decreases, the reflow property of a film increases, and the flatness of the film obtained improves. On the other hand, it is preferable to perform this heat processing on the board | substrate obtained by the said application | coating process on the single-plate hotplate.

Firing process

Subsequently, the film to which the said heat processing was given is baked at the temperature of 340-450 degreeC higher than the said heating temperature in the atmosphere of inert gas.

As the inert gas, it is preferable to use nitrogen gas, and if necessary, oxygen gas or air is added thereto, and an inert gas containing a small amount of oxygen (for example, oxygen of about 500 to 10,000 ppm by volume) is used. (It may be described in International Publication WO 01/48806 A1.)

Although the said baking temperature changes with the property of the silicon compound (namely, silica type film forming component) contained in the said coating liquid, etc., in order to obtain the silica type film which has hygroscopic resistance (hydrophobicity) and high film strength, it is 340-450 It is preferable to select from the temperature range of ° C.

Here, when the temperature of the baking treatment is less than 340 ° C., the crosslinking of the precursor of the silica-based coating-forming component is unlikely to proceed, so that a film having sufficient film strength cannot be obtained, and when the temperature of the baking treatment exceeds 450 ° C., For example, aluminum wirings, copper wirings, etc. constituting the semiconductor substrate may be oxidized or melted, which may cause fatal damage to the wiring layers.

In addition, although this baking process changes with the kind of coating liquid for film formation, the film thickness of a film, etc., it is preferable to carry out for 5 to 90 minutes, Preferably it is 10 to 60 minutes.

In addition, it is preferable to carry out this baking treatment by placing a substrate on a sheet type hot plate as in the case of the heating step.

The film thickness of the silica-based film thus obtained varies depending on the substrate for forming the film, its use, and the like. For example, the film thickness is usually 100 to 600 nm on a silicon substrate (silicon wafer) in a semiconductor device. It is 100-1000 nm normally between the wiring layers of a multilayer wiring.

[Silica-based film]

The silica-based coating according to the present invention can be easily formed using the above-described coating liquid for forming a silica-based coating, and has a Young's modulus of 3.0 GPa or more, more specifically 5.0 GPa or more, high film strength and relatively low relative dielectric constant. It is excellent in surface flatness, crack resistance, etc.

In the present invention, when the silica-based fine particles used in the preparation of the coating liquid for forming a film are used as the silica-based fine particles aged by hydrothermal treatment in a pressure vessel such as an autoclave, the Young's modulus is 6.0 GPa or more, More specifically, it is possible to form a silica-based film having a high film strength of 7.0 GPa or more.

In addition, since the silica-based coating according to the present invention is also strong in tensile strength, cracks and the like do not occur in the coating even if the thickness of the coating is increased. This is because the reaction product of the organosilicon compound partially hydrolyzed and / or hydrolyzed by the basic catalyst component released from the silica-based fine particles in the step of preparing the coating liquid for forming a film is the outer surface of the silica-based fine particles and its It is considered that this is because it is strongly bonded to the surface in the pores. Thereby, when forming the said film, even if the film shrink | contracts, since only the said silica type microparticles | fine-particles do not isolate | separate, a silica type film | membrane with strong crack resistance can be formed.

Moreover, according to the said coating liquid which concerns on this invention, the silica type film which has the smooth surface whose surface roughness (Rms) is 5.0 nm or less can be easily formed. (This surface roughness is atomic force microscope AFM. This is the square average roughness of the value measured by.) This eliminates the need for a complicated polishing process or the like for flattening the surface of the film formed on the substrate. In addition, pinholes or the like do not occur on the coating surface.

In addition, since the silica-based coating is a film having excellent hydrophobicity (hygroscopicity), even if it is left in an air atmosphere containing saturated water vapor, it may cause deterioration of the dielectric constant (that is, increase in the dielectric constant). none.

In addition, the silica-based coating is excellent in chemical resistance such as adhesion to film-forming surfaces such as a semiconductor substrate and alkali resistance, and further has excellent properties in process suitability such as oxygen plasma resistance and etching processability. .

The coating liquid according to the present invention capable of forming such a silica-based coating film is formed on a semiconductor substrate, a wiring layer having a multilayer wiring structure, a device surface and / or a PN junction portion, or a multilayer provided on the substrate. Is used to form a silica-based film, in particular, a silica-based insulating film between wiring layers. Among these, the coating liquid according to the present invention is suitable for use in forming an insulating film having a film thickness of about 1 to 5 μm.

[How to measure]

Next, the measuring method employ | adopted in the Example of this invention and others is concretely described as follows.

(1) Average particle diameter of silica-based fine particles

A TEM photograph taken of a 100,000-times magnified image of silica-based fine particles contained in a water-alcohol dispersion (sample) by a transmission electron microscope (TEM) (H-800, manufactured by Hitachi Hi-Tech Co., Ltd.). -AP), and the average particle diameter of the said silica fine particle is computed using attached analysis software.

(2) Content of basic catalyst component contained in silica-based fine particles

(a) In order to measure the total amount (for example, ammonia amount) of the basic catalyst component contained in the water-alcohol dispersion (sample) in which silica-based fine particles containing the basic catalyst component are dispersed, an aqueous sodium hydroxide solution is added to the After dissolving the silica fine particles, the alkaline gas generated by heating is absorbed into an aqueous solution containing lean acid (H ₂ SO ₄ : 0.05 mol / L). Subsequently, 2 to 3 drops of a methyl red solution are dropped thereon, titrated with an aqueous sodium hydroxide solution (NaOH: 0.1 moI / L), and the total amount (Q1) of the basic catalyst component contained in the dispersion is measured. .

(b) Next, the water-alcohol dispersion (sample) was centrifuged at a rotational speed of 3000 rpm (centrifugal concentrator: VS2001 manufactured by As One, centrifuge: KUBOTA 6930 manufactured by KUBOTA) to obtain silica-based fine particles contained in the dispersion. Separate. Subsequently, the total amount (Q2) of the basic catalyst component contained in the said dispersion medium is measured by the method similar to said (a) with the quantity (for example, ammonia amount) of the basic catalyst component contained in the obtained dispersion medium.

(c) Subtract the amount of basic catalyst component (Q2) measured in (b) from the amount of basic catalyst component (Q1) measured in (a) above to determine the amount (Q) of the basic catalyst component contained in the silica-based fine particles. Calculate.

(3) Viscosity measurement of coating liquid for film formation

1 mL of the coating liquid as a sample is transferred to a clay dish (VISCONIC ED type manufactured by Toki Sangyo Co., Ltd.), the rotor is brought into contact with the sample, and the torque value when the rotor is rotated at an existing rotational speed is measured. Next, a viscosity is computed from the torque value measured by the said rotation speed.

(4) Measurement of the number average molecular weight of the silicon compound

It measures by GPC (Gel Phase Chromatography) method using the molecular weight measuring apparatus (GPC8020 made by Tosoh Corporation). That is, 1 mL of the coating solution as a sample is placed in a solution separation solution, and the molecular component in the sample is separated according to the size of the hydrodynamic volume by passing through a gel column (linking TSKgel manufactured by Tosoh Corporation, G5000Hxl manufactured by Tosoh Corporation, and TSKgel G3000Hxl). The molecular weight distribution is then measured by the difference in refractive index with the reference for each time. Next, the number average molecular weight of polystyrene conversion is computed by converting the measured molecular weight distribution in comparison with the distribution of the polystyrene which has the existing molecular weight measured beforehand.

(5) Ion concentration measurement of coating liquid for film formation

10 mL of the coating liquid as a sample is mixed with 90 mL of purified pure water, stirred at room temperature for 1 hour, and then the mixed liquid is filtered, and 100 mL of purified pure water is further passed through the filtered medium to recover the filtrate. Subsequently, cation concentrations of metal ions and the like contained in the recovered filtrate are measured by atomic absorption method, and anion concentrations of basic catalyst components and the like are measured by ion chromatography.

(6) relative dielectric constant of silica based coating

The coating liquid as a sample was applied on a silicon wafer by a spin coating method at a rotational speed of 4000 rpm, dried at a temperature of 120 ° C. for 5 minutes, and then baked at a temperature of 350 ° C. under a nitrogen atmosphere for 30 minutes to form a coating film (silica film). ). Next, it measures by the mercury probe method (SSM495 by Solid State Measurements, frequency 1MHz). In other words, the mercury electrode is brought into contact with the coating film, the voltage is changed to measure the capacitance of the coating film, and the relative dielectric constant of the coating film is calculated from the obtained capacitance and film thickness.

(7) Film strength of silica based film

The coating liquid as a sample was applied on a silicon wafer by a spin coating method at a rotational speed of 4000 rpm, dried at a temperature of 120 ° C. for 5 minutes, and then baked at a temperature of 350 ° C. under a nitrogen atmosphere for 30 minutes to form a coating film (silica film). ). Next, Young's Modulus is measured by the nanoindentation method (nanoindenter Xp manufactured by MTS Systems Corp.). That is, a diamond indenter is pushed into the coating film, the contact area and the push strength of the indenter and the coating film are measured, and the Young's modulus is calculated.

(8) Crack resistance limit film thickness of silica-based film

The coating liquid as a sample was applied on a silicon wafer by a spin coating method at a rotational speed of 300 to 700 rpm, dried at a temperature of 120 ° C. for 5 minutes, and then baked at a temperature of 350 ° C. under a nitrogen atmosphere for 30 minutes to form a coating film (silica). Cinnamon film). Next, the obtained coating film is observed under a microscope (magnification: 50 times) to confirm the presence of cracks. In addition, the limit film thickness at which cracking does not occur is measured by a contact stepped film thickness measuring method (SURFCOM1400D manufactured by ACCRETECH).

(9) Surface roughness of silica based coating

The coating liquid as a sample was applied on a silicon wafer by a spin coating method at a rotational speed of 4000 rpm, dried at a temperature of 120 ° C. for 5 minutes, and then baked at a temperature of 350 ° C. under a nitrogen atmosphere for 30 minutes to form a coating film (silica film). ). Subsequently, a cantilever with a probe (NCH-10V manufactured by Nihon Biko Co., Ltd.) having conductivity applied to the coating film is scanned, and the surface shape is observed from the intermolecular force of the probe and the coating film, and the surface roughness (Rms) is calculated.

EXAMPLE

Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to this Example.

Preparation of Silica-based Fine Particles

Preparation Example 1

1268 g of a base material consisting of 508 g of methanol (manufactured by Kantogagaku Co., Ltd.) and 760 g of pure water at a concentration of 99.9% by weight was prepared. 16048 g of methanol at a concentration of 99.9 wt% and 8452 g of ethyl silicate (manufactured by Tamagagaku Kogyo Co., Ltd.) were added to prepare 24500 g of the stirred ethyl silicate solution.

Subsequently, 1268 g of the substrate was heated to maintain a temperature of 65 ° C., to which 24500 g of the above ethyl silicate solution and 9490 g of ammonia water at a concentration of 1.9 wt% were simultaneously added over 5 hours under stirring. After completion of the addition, further aging was performed at the temperature for 3 hours to give 35258 g of a water-methanol dispersion (hereinafter, referred to as a 'water-methanol dispersion') containing 7.4% by weight of silica fine particles.

Subsequently, the obtained water-methanol dispersion was cooled to room temperature, 20340 g of pure water was added to 31860 g of the water-methanol dispersion, and stirred, followed by an ultrafiltration filter (Asahi Kasei Co., Ltd. product, ACP-) under a temperature condition of 25 ° C. 2013), and the weight was concentrated to 18711 g. This obtained 18711 g of water-methanol dispersions (hereinafter, referred to as 'water-methanol purified liquid') from which unreacted or intermediate reactants of the ethyl silicate contained in the water-methanol dispersion were removed.

Subsequently, 13860 g of 99.5% by weight of ethanol (manufactured by Wako Pure Chemical Industries, Ltd.) was added to 10395 g of the water-methanol purified liquid obtained above, followed by stirring, using the ultrafiltration filter under a temperature condition of 25 ° C. The weight was concentrated to 10395 g. In addition, 13860 g of ethanol was added to the obtained dispersion, followed by stirring. Then, the resultant was concentrated using the ultrafiltration filter until the weight became 10395 g. As a result, 10395 g of a water-ethanol dispersion liquid (hereinafter, referred to as a "water-ethanol dispersion liquid") containing silica fine particles obtained by solvent-substituting water and methanol contained in the water-methanol purified liquid was obtained.

2703 g of ethanol was added to this water-ethanol dispersion to adjust the concentration of the silica-based fine particles contained in the dispersion to 10% by weight, and concentrated using a rotary evaporator (RE20EU manufactured by Shibatagagaku Co., Ltd.) to obtain silica fine particles. 6752 g of sample 1A of a water-ethanol dispersion containing 19.4 wt% was obtained.

Thus, when the average particle diameter of the silica type microparticles | fine-particles contained in the obtained sample 1A was measured, it was about 20 nm.

In addition, as shown in Table 1, the total content of ammonia contained in Sample 1A and the content of ammonia contained in the silica-based fine particles were measured by the above method.

Preparation Example 2

In the same manner as in Preparation Example 1, 18711 g of a water-methanol purified liquid was prepared.

Next, 10150 g of the prepared water-methanol purified liquid was taken out, and 47 g of ammonia water at a concentration of 29% by weight was added to the mixture, followed by stirring. The mixture was treated at a temperature of 15 hours for 15 hours to mature the silica fine particles contained in the water-methanol purified liquid.

Next, 10045 g of the water-methanol purified liquid (maturated liquid) obtained by cooling this to room temperature was taken out, and 13020 g of pure water was added and stirred, and the weight was 9998 g using an ultrafiltration filter under a temperature condition of 25 ° C. Concentrate until. After further adding and stirring 13020 g of pure water, using the ultrafiltration filter, the process of concentrating until the weight became 9998 g was repeated twice. As a result, 9998 g of a water-methanol purified liquid obtained by partially removing ammonia contained in the silica-based fine particles was obtained.

Subsequently, 13331 g of ethanol (manufactured by Wako Pure Chemical Industries, Ltd.) was added to 9998 g of the water-methanol purified liquid obtained above, followed by stirring using an ultrafiltration filter under a temperature condition of 25 ° C. The weight was 9998 g. Concentrate until In addition, 13331 g of ethanol was added thereto, stirred, and then concentrated using the ultrafiltration filter until the weight was 9998 g. This obtained 9998 g of water-ethanol dispersions which carried out solvent substitution of the water and methanol contained in the said water-methanol dispersion liquid.

2600 g of ethanol was added to this water-ethanol dispersion to adjust the concentration of the silica-based fine particles contained in the dispersion to 10% by weight, and concentrated using a rotary evaporator (RE20EU manufactured by Shibatagagaku Co., Ltd.) to obtain silica fine particles. 6494 g of sample 2A of a water-ethanol dispersion containing 19.4 wt% was obtained.

Thus, when the average particle diameter of the silica type microparticles | fine-particles contained in the said sample 2A obtained was measured, it was 25 nm in general.

In addition, as in the case of Preparation Example 1, the total content of ammonia contained in Sample 2A and the content of ammonia contained in the silica-based fine particles were measured by the above method, and it was as shown in Table 1.

Example 1

6050 g of each of Sample 1A prepared in Preparation Example 1 and Sample 2A (both water-ethanol dispersion containing 19.4% by weight of silica fine particles) prepared in Preparation Example 2 were taken out, and methyltrimethoxysilane (MTMS) was added thereto. 1778 g of Shin-Etsu Chemical Co., Ltd. and 1409 g of nitric acid (Kanto-Togaku Co., Ltd.) aqueous solution of 0.44 weight% concentration were mixed, and it heated gradually to room temperature of 50 degreeC. Furthermore, the said methyl trimethoxysilane was partially hydrolyzed and / or hydrolyzed while keeping at this temperature (50 degreeC), stirring for 15 hours at a speed | rate of 200 rpm.

At this time, the pH of the mixed solution was measured. The sample 1A was initially used (before heating) at pH 2.1 due to the effect of nitric acid added as an acidic catalyst component, but became pH 7.8 with an increase in temperature and stabilized in that state. . In addition, although the said sample 2A was used initially (before heating), it was pH 2.4 under the influence of nitric acid added as an acidic catalyst component, but it became pH 8.0 with temperature rise, and was stabilized in that state. That is, it was found that ammonia as the basic catalyst component was released from the silica-based fine particles contained in the sample, contributing to the partial hydrolysis reaction and / or the hydrolysis reaction of the methyltrimethoxysilane.

Subsequently, the obtained water-ethanol dispersion liquid is provided to a rotary evaporator (RE20EU manufactured by Shibataga Chemical Co., Ltd.), and water, ethanol, and the like contained in the dispersion liquid are produced by propylene glycol monopropyl ether (PGP, Japan Emulsifier Co., Ltd. product). ) And solvent. In addition, the content of the silicon compound contained in this solvent-substituted PGP solution was adjusted to 25% by weight based on SiO ₂ , and the coating liquid 3A for forming a silica-based coating film (prepared using the above sample 1A, Sample 3A) and 4A (prepared using Sample 2A above, hereinafter referred to as Sample 4A) were obtained.

Thus, the obtained sample was left to stand at room temperature for 150 days, and the storage stability of the coating liquid was confirmed by the viscosity change, and it turned out that there is no change.

Table 2 shows the properties of the obtained coating liquid for forming a silica-based film.

Example 2

6050 g of each of Sample 1A prepared in Preparation Example 1 and Sample 2A (both water and ethanol dispersions) prepared in Preparation Example 2 were taken out, and methyltrimethoxysilane (MTMS, Shin-Etsu Chemical Co., Ltd. ) 2668 g and 1691 g of nitric acid (manufactured by Kanto Chemical Co., Ltd.) at a concentration of 0.44% by weight were mixed and gradually heated from room temperature to a temperature of 50 ° C. Moreover, the said partial hydrolysis and / or hydrolysis of the said methyl trimethoxysilane was performed, maintaining this temperature (50 degreeC) and stirring for 15 hours at a speed | rate of 200 rpm.

When the pH of the mixed liquid at this time was measured, initially (before heating) was pH 2.3 under the influence of nitric acid added as an acidic catalyst component, but it became pH 7.5 with the temperature rise, and it stabilized in that state. In other words, it was found that ammonia as the basic catalyst component was released from the silica-based fine particles contained in the sample, contributing to the partial hydrolysis reaction and / or hydrolysis reaction of the methyltrimethoxysilane.

Subsequently, the obtained water-ethanol dispersion was supplied to a rotary evaporator (RE20EU manufactured by Shibatagagaku Co., Ltd.), and water, ethanol, and the like contained in the dispersion were mixed with propylene glycol monopropyl ether (PGP, manufactured by Japan Emulsifier Co., Ltd.). ) And solvent. Further, the solvent replacement with PGP the content of the silicon compound contained in the solution, a SiO ₂ basis, adjusted to 25% by weight, and a silica-containing coating liquid for forming a coating film 5A (to be prepared by using the samples 1A, below, Sample 5A) and 6A (prepared using Sample 2A above, hereinafter referred to as Sample 6A) were obtained.

Thus, the obtained sample was left to stand at room temperature for 150 days, and the storage stability of the coating liquid was confirmed by the viscosity change, and it turned out that there is no change.

Table 2 shows the properties of the obtained coating liquid for forming a silica-based film.

Example 3

Sample 2A prepared in Preparation Example 2, phenyltrimethoxysilane (PhTMS, manufactured by Shin-Etsu Chemical Co., Ltd.) and phenyltrichlorosilane (PhTCS, Shin-Etsu Chemical Co., Ltd.) instead of methyltrimethoxysilane. Except for each of the above), 7A of the coating liquid for forming a silica-based coating film containing 25% by weight of a silicon compound as a reactant, based on SiO ₂ , in the same manner as in Example 1 (Sample 2A and Phenyltrimethoxysilane It was prepared using the following, hereinafter referred to as sample 7A) and 8A (was prepared using the sample 2A and phenyltrichlorosilane, hereinafter referred to as sample 8A).

Thus, the obtained sample was left to stand at room temperature for 150 days, and the storage stability of the coating liquid was confirmed by the viscosity change, and it turned out that there is no change.

Table 2 shows the properties of the obtained coating liquid for forming a silica-based film.

Comparative Example 1

Until the water-methanol purified liquid was obtained, 9998 g of water-methanol purified liquid was obtained by the method similar to the preparation example 1.

Subsequently, in order to reduce the ammonia concentration, 13331 g of pure water was added to 9998 g of water-methanol purified liquid, and then stirred, and then concentrated using an ultrafiltration filter under a temperature condition of 25 ° C. until the weight became 9998 g. Subsequently, 13331 g of ethanol (manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred, and then concentrated using an ultrafiltration filter under a temperature condition of 25 ° C until the weight became 9998 g. Furthermore, 13331 g of ethanol was added thereto, stirred, and then concentrated using the ultrafiltration filter until the weight was 9998 g. This obtained 9998 g of the water-ethanol dispersion liquid which carried out the solvent substitution of water and methanol contained in the said water-methanol purification liquid.

2560 g of ethanol was added to this water-ethanol dispersion, the concentration of the silica-based fine particles contained in the dispersion was prepared at 10% by weight, and further concentrated using a rotary evaporator (RE20EU manufactured by Shibatagagaku Co., Ltd.), 6494 g of the sample 9A of the water-ethanol dispersion containing 19.4 weight% of silica fine particles was obtained.

Thus, the average particle diameter of the silica fine particles contained in Sample 9A thus obtained was found to be approximately 25 nm.

In addition, as in the case of Preparation Example 1, the total content of ammonia contained in the sample 9A and the content of ammonia contained in the silica-based fine particles were measured by the above method, and it was as shown in Table 1 below.

A partial hydrolysis and / or hydrolysis of the methyltrimethoxysilane was carried out in the same manner as in Example 1 except that Sample 9A was used.

When the pH of the mixed solution in the case of using the sample 9A was measured, initially (before heating) was pH 2.2 under the influence of nitric acid added as an acidic catalyst component, but gradually increased with the temperature increase to pH 4.1. In other words, it was found that the amount of ammonia released from the silica-based fine particles as the basic catalyst component is insufficient, and there are few alkaline catalysts that contribute to the partial hydrolysis reaction and / or hydrolysis reaction of the methyltrimethoxysilane.

Subsequently, the obtained water-ethanol dispersion was supplied to a rotary evaporator (RE20EU manufactured by Shibatagagaku Co., Ltd.), and water, ethanol, and the like contained in the dispersion were propylene glycol monopropyl ether (manufactured by PGP Japan Emulsifier Co., Ltd.). And solvent substitution. Further, the solvent replacement with PGP the content of the silicon compound contained in the solution, a SiO ₂ basis, adjusted to 25% by weight, and a silica-containing coating liquid for forming a coating film 10A (to be prepared using the sample 9A, or less, Sample 10A).

Thus, the obtained sample was left to stand at room temperature for 150 days, and the storage stability of the coating liquid was confirmed by the viscosity change, and it turned out that there is no change.

Table 2 shows the properties of the obtained coating liquid for forming a silica-based film.

Comparative Example 2

Until the water-methanol purified liquid was obtained, 18711 g of samples of the water-methanol purified liquid were prepared by the method similar to the preparation example 1.

Next, 10150 g of the water-methanol purified liquid was taken and in order to increase the ammonia concentration in the sample, 190 g of 29% by weight of ammonia water was added to the water-methanol purified liquid, followed by stirring, followed by autoclave (pressure-resistant glass). It was put into the high school Co., Ltd. product, TAS-13 type | mold, and it processed at the temperature of 150 degreeC for 15 hours, and the silica fine particle contained in the said water-methanol purification liquid was aged.

Next, 10045 g of 10340 g of water-methanol purified liquid (aging liquid) obtained by cooling this to room temperature was taken out, 13020g of pure waters were added, and it stirred, and the weight was obtained using the ultrafiltration filter on 25 degreeC temperature conditions. Concentrated until this amount was 9861 g. After adding 13020 g of pure water and further stirring, using the ultrafiltration filter, the operation of concentrating until the weight became 9861 g was repeated twice. As a result, 9861 g of a water-methanol purified liquid obtained by partially removing ammonia contained in the silica-based fine particles was obtained.

Subsequently, 13147 g of ethanol (manufactured by Wako Pure Chemical Industries, Ltd.) was added to 9861 g of the water-methanol purified liquid obtained as described above and stirred, and the weight thereof was 9861 g using an ultrafiltration filter under a temperature condition of 25 ° C. Concentrate until. In addition, 13147 g of ethanol was added to the mixture, followed by stirring. Then, the resultant was concentrated using the ultrafiltration filter until the weight was 9861 g. This obtained 9861 g of water-ethanol dispersion liquid which solvent-substituted water and methanol contained in the said water-methanol purification liquid, respectively.

2564 g of ethanol was added to this water-ethanol dispersion, the concentration of the silica fine particles contained in the dispersion was prepared at 10% by weight, and further concentrated using a rotary evaporator (RE20EU manufactured by Shibatagagaku Co., Ltd.), 6404 g of sample 11A of a water-ethanol dispersion containing 19.4 wt% of silica fine particles was obtained.

Thus, when the average particle diameter of the silica type microparticles | fine-particles contained in obtained sample 11A was measured, it was 25 nm in general.

In addition, as in the case of Preparation Example 1, the total content of the ammonia contained in the sample 11A and the content of the ammonia contained in the silica-based fine particles were measured by the above method, and it was as shown in Table 1 below.

A partial hydrolysis and / or hydrolysis of the methyltrimethoxysilane was carried out in the same manner as in Example 1 except that Sample 11A was used.

When pH of the mixed liquid at the time of using the said sample 11A was measured, initially (before heating) was pH 8.3, and it increased slightly with the temperature rise, and became pH 8.5. Thus, despite the same amount and mixing of nitric acid as the acidic catalyst, the pH value was high from the beginning, and the reason that the value did not change mostly was not only large amount of ammonia contained in the water-ethanol dispersion of Sample 11A, but also silica. This is because ammonia as the basic catalyst component is present in a large amount in the system fine particles. Thereby, it is anticipated that the hydrolysis reaction of the said methyl trimethoxysilane is advanced too much by the excess ammonia (basic catalyst component).

Subsequently, the obtained water-ethanol dispersion was supplied to a rotary evaporator (RE20EU manufactured by Shibatagagaku Co., Ltd.), and water, ethanol, and the like contained in the dispersion were propylene glycol monopropyl ether (manufactured by PGP Japan Emulsifier Co., Ltd.). Was substituted with solvent. In addition, the content of the silicon compound contained in the PGP solution replaced the solvent, the SiO ₂ basis, adjusted to 25% by weight, the silica-based coating liquid for forming a coating film sample 12A (to be prepared by use of the sample 11A, Hereinafter, sample 12A) was obtained.

Thus, the obtained sample was left to stand at room temperature for 150 days, and when the storage stability of the coating liquid was observed, it turned out that it was changing into the gel state. Thus, it was found that the coating liquid prepared by partially hydrolyzing and / or hydrolyzing alkoxysilane or the like using a water-ethanol dispersion containing silica-based fine particles having ammonia content exceeding 1100 ppm had problems in its storage stability. Could.

Table 2 shows the properties of the obtained coating liquid for forming a silica-based film.

Comparative Example 3

Using the sample 2A prepared in Preparation Example 2 and methyltrimethoxysilane (MTMS, manufactured by Shin-Etsu Chemical Co., Ltd.), the heating temperatures were 20 ° C (room temperature) and 90 ° C (90 ° C from room temperature, respectively). Except for heating to), 13A of a coating liquid for forming a silica-based coating film containing 25% by weight of a silicon compound as a reactant based on SiO _{2 in the} same manner as in Example 1 (prepared at a heating temperature of 20 ° C.) , Sample 13A), and 14A (prepared at heating temperature of 90 ° C., hereinafter referred to as sample 14A) were obtained.

Thus, the obtained sample was left to stand at room temperature for 150 days, and when the storage stability of the coating liquid was confirmed by the viscosity change, it turned out that there is no change about coating liquid 13A. However, it was found that the coating liquid 14A was changed into a gel state. Thus, when 90 degreeC is employ | adopted as a heating temperature, since ammonia (basic catalyst component) contained in silica type microparticles | fine-particles is discharged out of a particle | grain in a short time, it causes a hydrolysis reaction, such as an alkoxysilane, to apply rapidly, and a coating liquid It was found that the preservation stability of the was impaired.

Table 2 shows the properties of the obtained coating liquid for forming a silica-based film.

Example 4 and Comparative Example 4

5 ml of each of the samples 3A, 4A, 5A, 6A, 7A, 8A, 10A, and 13A adjusted in Examples 1 to 3 and Comparative Examples 1 and 3, respectively, using a conventionally known spin coating method (manufactured by MIKASA: 1H-3608) It was dripped on the 6-inch-size silicon wafer board | substrate, and the coating process was performed for 20 second at the speed of 4000 rpm. These operations were repeated to obtain substrates 3B, 4B, 5B, 6B, 7B, 8B, 10B and 13B subjected to the coating treatment. Subsequently, these board | substrates were mounted on the hotplate (EC-1200 by IUCHI), and it heat-processed at 120 degreeC for 5 minutes in air | atmosphere atmosphere. In this heat treatment step, the organic solvent (PGP) or the like contained in the coating evaporates, and these were discharged out of the system.

Furthermore, while these board | substrates were mounted on the hotplate, the processing environment was changed from atmospheric atmosphere to nitrogen gas atmosphere, and baking process was performed at 350 degreeC for 30 minutes. Next, after cooling these board | substrates to the temperature near room temperature, it took out out of the system.

The film thickness of the silica-based coating film formed on the substrate thus obtained was about 500 nm.

Next, the dielectric constant, film strength (Young's modulus), and surface roughness of the silica-based coating film formed on the substrate were measured by the above method. These measurement results are shown in Table 3.

Example 5 and Comparative Example 5

5 ml of each of Samples 3A, 4A, 5A, 6A, 7A, 8A, 10A, and 13A adjusted in Examples 1 to 3 and Comparative Examples 1 and 3, respectively, using a conventionally known spin coating method (1H-360S manufactured by MIKASA) It was dripped on the 6-inch-size silicon wafer board | substrate, and the coating process was performed for 20 second at the speed of 300 rpm-700 rpm. These operations were repeated to obtain substrates 3C, 4C, 5C, 6C, 7C, 8C, 10C and 13C subjected to the coating treatment.

Subsequently, these board | substrates were mounted on the hotplate (EC-1200 by IUCHI company), and it heat-processed at 120 degreeC for 5 minutes in air atmosphere. In this heat treatment step, the organic solvent (PGP) or the like contained in the coating evaporates, and these were discharged out of the system.

Furthermore, while these board | substrates were mounted on the sheet | leaf hot plate, the processing environment was changed from air atmosphere to nitrogen gas atmosphere, and baking process was performed at 350 degreeC for 30 minutes. Next, after cooling these board | substrates to the temperature near room temperature, it took out out of the system.

The limit film thickness which a crack does not generate | occur | produce in the silica type film obtained by baking in this way was measured by said method. The measurement results are shown in Table 4.

As is also apparent from the above results (Tables 3 and 4), when the coating liquid samples 3A, 4A, 5A, 6A, 7A, and 8A prepared in Examples 1 to 3 were used, a film having a high Young's modulus of 6.0 GPa or more was used. A silica-based coating film having strength, relatively low relative dielectric constant, and excellent surface flatness, crack limit film thickness and the like was obtained.

On the other hand, when 10 A of the coating liquid sample prepared in the comparative example 1 was used, the crack limit film thickness fell remarkably and the film strength also fell. This is because the amount of the basic catalyst component contained in the silica-based fine particles in the water-ethanol dispersion sample 9A used for the preparation of the coating liquid sample 10A is small, so that the partial hydrolysis reaction and / or the hydrolysis of the methyltrimethoxysilane This is because the alkaline catalyst contributing to the decomposition reaction is less emitted from the silica-based fine particles, and the bonding with the silica-based fine particles by partial hydrolysis and / or hydrolysis of the organosilicon compound is insufficient.

Moreover, when the coating liquid sample 13A prepared in the comparative example 3 was used, it turned out that a crack limit film thickness falls remarkably and a film strength also falls. Since the heating temperature is low at 20 ° C., the release of the basic catalyst component from the silica-based fine particles contained in the silica-based fine particles in the water-ethanol dispersion sample 2A used for the preparation of the coating liquid sample 13A is not sufficient. This is because bonding with the silica-based fine particles by partial hydrolysis and / or hydrolysis of the organosilicon compound is insufficient.

Claims (21)

At least one organosilicon compound selected from the alkoxysilane represented by the following general formula (I), the halogenated silane represented by the following general formula (II), and partial hydrolyzate thereof, and the silica-based fine particles containing a basic catalyst component A coating liquid for forming a silica-based coating film comprising a silicon compound obtained by heating a dispersion liquid contained therein and at least partially hydrolyzing and / or hydrolyzing the organosilicon compound with the basic catalyst component released from the silica-based fine particles. R _n Si (OR ′) _4-n ... (Ⅰ) R _n SiX _{4- n} . (Ⅱ) (Wherein R represents a hydrogen atom, a fluorine atom or an alkyl group having 1 to 8 carbon atoms, a fluorine-substituted alkyl group, an aryl group, a vinyl group or a phenyl group, and R 'represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms or aryl) Group, a vinyl group, or a phenyl group, X represents a halogen atom, and n is an integer of 0 to 3.) The coating liquid for forming a silica-based film according to claim 1, wherein the dispersion is a water-alcoholic dispersion containing water and an alcohol. The coating liquid for forming a silica-based film according to any one of claims 1 to 2, further comprising a basic catalyst component and / or an acidic catalyst component in the dispersion. The silica according to any one of claims 1 to 3, wherein the basic catalyst component is at least one member selected from ammonia, ammonium hydroxide, quaternary ammonium compound, organic amine and amine coupling agent. Coating liquid for forming a cinnamon film. The coating liquid for forming a silica-based film according to claim 3, wherein the acidic catalyst component is at least one selected from nitric acid, hydrochloric acid, acetic acid, and sulfuric acid. The silica-based fine particles according to any one of claims 1 to 5, wherein the silica-based fine particles are obtained by hydrolyzing and polycondensing the alkoxysilane represented by the following general formula (I) in the presence of the basic catalyst component. And the amount of the basic catalyst component contained in the silica-based fine particles is adjusted. R _n Si (OR ′) _4-n ... (Ⅰ) (Wherein R represents a hydrogen atom, a fluorine atom or an alkyl group having 1 to 8 carbon atoms, a fluorine-substituted alkyl group, an aryl group, a vinyl group or a phenyl group, and R 'represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms or aryl) Group, vinyl group or phenyl group, and n is an integer of 0-3.) The coating liquid for forming a silica-based film according to any one of claims 1 to 6, wherein the silica-based fine particles contain the basic catalyst component in a range of 200 to 1100 ppm by weight. The reactant according to any one of claims 1 to 7, wherein the silicon compound is a reactant in which the organosilicon compound is partially hydrolyzed and / or hydrolyzed by at least the basic catalyst component released from the silica-based fine particles. A coating liquid for forming a silica-based coating film comprising silica-based fine particles, and at least a part of the reactant is bonded to an outer surface of the silica-based fine particles and an inner surface of the pores thereof. 8. The silicon compound according to any one of claims 3 to 7, wherein the silicon compound is contained in the dispersion by the basic catalyst component and / or the acidic catalyst component and the basic catalyst component released from the silica-based fine particles. Wherein the organosilicon compound comprises a partially hydrolyzed and / or hydrolyzed reactant and the silica-based fine particles, and at least a portion of the reactant is bonded to the outer surface of the silica-based fine particles and the surface in the pores thereof. Coating liquid for forming a silica-based film. The coating liquid for forming a silica-based film according to any one of claims 1 to 9, wherein the silicon compound has a number average molecular weight of 500 to 5000 on a polystyrene conversion basis. The coating liquid for forming a silica-based coating film according to any one of claims 1 to 10, wherein an ion concentration contained in the coating liquid is 1.0 millimoles / liter or less. (a) A water-alcohol-based dispersion liquid of silica fine particles obtained by hydrolysis and polycondensation reaction of an alkoxysilane represented by the following general formula (I) in the presence of a basic catalyst component is filtered through an ultrafiltration device, A step of preparing a water-alcoholic dispersion of silica-based fine particles in which content is adjusted; (b) at least one selected from alkoxysilanes represented by the following general formula (I), halogenated silanes represented by the following general formula (II), and partial hydrolyzates thereof in the water-alcohol dispersion liquid containing the silica-based fine particles Mixing a water dispersion containing an organosilicon compound, and (c) The silicon compound obtained by the process of heating the said mixture liquid at the temperature of 30-80 degreeC, and partially hydrolyzing and / or hydrolyzing the said organosilicon compound with the said basic catalyst component discharge | released from the said silica type microparticles | fine-particles at least. Method for preparing a coating liquid for forming a silica-based film comprising a. R _n Si (OR ′) _4-n ... (Ⅰ) R _n SiX _{4- n} . (Ⅱ) (Wherein R represents a hydrogen atom, a fluorine atom or an alkyl group having 1 to 8 carbon atoms, a fluorine-substituted alkyl group, an aryl group, a vinyl group or a phenyl group, and R 'represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms or aryl) Group, a vinyl group or a phenyl group, X represents a halogen atom, and n is an integer of 0-3.) The method for preparing a coating liquid for forming a silica-based coating film according to claim 12, wherein the content of the basic catalyst component contained in the silica-based fine particles obtained in the step (a) is in the range of 200 to 1100 ppm by weight. . The coating liquid for forming a silica-based coating film according to any one of claims 12 to 13, further comprising a basic catalyst component and / or an acidic catalyst component in the dispersion liquid prepared in the step (b). Method of preparation The silica according to any one of claims 12 to 14, wherein the basic catalyst component is at least one member selected from ammonia, ammonium hydroxide, quaternary ammonium compound, organic amine and amine coupling agent. A method for preparing a coating liquid for forming a cinnamon film. 15. The method for preparing a coating liquid for forming a silica-based coating film according to claim 14, wherein the acidic catalyst component is at least one selected from nitric acid, hydrochloric acid, acetic acid, and sulfuric acid. It has high film | membrane strength and comparatively low dielectric constant obtained by apply | coating the coating liquid for film formation in any one of Claims 1-11 on a board | substrate, and drying and baking, and also has surface flatness and crack resistance Silica based film with excellent properties. 18. The silicon compound according to claim 17, wherein at least a part of the reactant obtained by the silica-based coating partially hydrolyzes and / or hydrolyzes the organosilicon compound is bonded to the outer surface of the silica-based fine particles and the surface of the pores thereof. Silica-based film comprising a polycondensate. The silica-based coating according to any one of claims 17 to 18, wherein the silica-based coating has a film strength of at least 3.0 GPa. The silica-based coating according to any one of claims 17 to 19, wherein the silica-based coating is a silica-based coating having a smooth surface having a surface roughness (Rms) of 5.0 nm or less. The silica-based coating according to any one of claims 17 to 20, wherein the silica-based coating is a silica-based insulating film.