JP2007031696A - Resin composition, silica-based coating film, method for producing the same, layered product and electronic part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition capable of forming a silica-based coating film having excellent resistance to alkali treatment and keeping sufficient adhesiveness to the adjacent layer. <P>SOLUTION: The resin composition for forming a silica-based coating film contains (a) a siloxane resin produced by the hydrolytic condensation of a raw material component containing a silicon compound of general formula (1) and (b) a solvent dissolving the component (a). The ratio M of all atoms derived from the group R<SP>1</SP>bonded to the Si atom is 0.50-1.00 mol. In the formula, R<SP>1</SP>is an atom of H or F or a group containing B, N, Al, P, Si, Ge or Ti or is a 1-20C organic group; X is a hydrolyzable group; and n is an integer of 0-2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a resin composition, a silica-based coating and a method for producing the same, a laminate, and an electronic component.

  The silica-based film formed by the sol-gel reaction generally has low alkali treatment resistance as described in Patent Document 1 below. For this reason, it is difficult to perform an alkali treatment on a substrate or the like in which the silica-based film is exposed or the silica-based film is exposed by the alkali treatment even if it is not exposed before the alkali treatment. There was a trend.

  For example, a silica-based film is used as an antireflection film. In this case, however, there is a problem that the silica-based film is deteriorated in an alkali treatment performed when the antireflection film is attached to the deflection plate. In addition, when a metal layer is formed on a substrate made of a silica-based film and the metal layer is patterned with an alkali using a resist, there is a problem that the substrate is deteriorated.

On the other hand, Patent Document 1 below describes that alkali treatment resistance can be improved by combining a silica matrix with a fluorine-containing organic polymer, but these must be combined in consideration of mutual interaction. Has been. And in patent document 1, the coating (antireflection film) which is excellent in alkali processing tolerance by using the silica monomer which has the alkoxy group by which the substituent containing a polymerizable ethylenically unsaturated group was introduce | transduced as a raw material of a silica matrix. ) Is obtained. Patent Document 2 below discloses an antireflection film having a siloxane resin composition in which a polysiloxane resin having a substituent containing fluorine and colloidal silica are combined.
Japanese Patent Laid-Open No. 2002-243907 JP 2000-121803 A

  However, when a fluorine-containing organic polymer is combined or a fluorine-containing silica monomer is used as in the above prior art, the adhesion to an adjacent layer of the resulting silica-based coating tends to be insufficient. .

  Then, this invention is made | formed in view of such a situation, and while providing the outstanding alkali treatment tolerance, the resin composition which can form the silica-type film which has the outstanding adhesiveness with respect to an adjacent layer is provided. For the purpose. Another object of the present invention is to provide a silica-based film using such a resin composition, a method for producing the same, a laminate, and an electronic component.

  It is estimated that the improvement effect of alkali treatment resistance by the combination of the fluorine-containing organic polymer as in the above prior art and the use of the fluorine-containing silica monomer is caused by the water repellency effect by fluorine atoms, fluorine-containing substituents or resins. Is done.

  On the other hand, the present inventors have examined a method for improving the alkali treatment resistance of the silica-based coating other than the conventional method using fluorine, and as a result, identified as a raw material for forming the silica-based coating. The present inventors have found a new finding that by using a resin composition containing a siloxane resin, the mechanical strength and density of a silica-based film can be increased to improve alkali treatment resistance. That is, it has been conceived that the alkali treatment resistance is improved by increasing the density of the silica-based film and suppressing the intrusion of the chemical solution.

［式中、Ｒ^１は、Ｈ及びＦのうちのいずれか一方の原子、Ｂ、Ｎ、Ａｌ、Ｐ、Ｓｉ、Ｇｅ若しくはＴｉを含む基、又は、炭素数１〜２０の有機基を示し、Ｘは加水分解性基を示し、ｎは０〜２の整数である。ただし、Ｒ^１又はＸが複数存在する場合、これらはそれぞれ同一でも異なっていてもよい。］ The present invention has been made on the basis of the above findings, and is a resin composition for forming a silica-based film, comprising (a) a raw material component containing a silicon compound represented by the following general formula (1): A siloxane resin obtained by hydrolysis and condensation, and a solvent capable of dissolving the components (b) and (a), bonded to silicon atoms per mole of silicon atoms constituting the siloxane bond in the siloxane resin. The total content ratio M of H atom, F atom, B atom, N atom, Al atom, P atom, Si atom, Ge atom, Ti atom or C atom is 0.50 to 1.00 mol. Features.

[Wherein, R ¹ represents any one atom of H and F, a group containing B, N, Al, P, Si, Ge, or Ti, or an organic group having 1 to 20 carbon atoms, X represents a hydrolyzable group, and n is an integer of 0-2. However, when two or more R < ¹ > or X exists, these may be same or different, respectively. ]

The resin composition of the present invention can form a silica-based film mainly composed of a siloxane resin contained therein. Since this siloxane resin has the functional group represented by R ¹ derived from the silicon compound of the general formula (1) in the above-mentioned specific content range, it has a dense structure, and the penetration of the chemical solution Is extremely unlikely to occur. For this reason, the silica-type film obtained from the resin composition of this invention has the outstanding alkali treatment tolerance. In addition, such a silica-based film can exhibit excellent alkali treatment resistance by taking such a dense structure, and it is not necessary to introduce excess fluorine as in the above-described prior art. Have good adhesion.

  In the resin composition of the present invention, the M is preferably 0.55 to 0.90, more preferably 0.60 to 0.80, and still more preferably 0.62 to 0.75. By satisfying these conditions, it becomes easy to achieve both excellent alkali treatment resistance and adhesion.

Moreover, the silicon compound which is a raw material of the siloxane resin is a group containing H atom, B, N, Al, P, Si, Ge or Ti as a group represented by R ¹ , or a group having 1 to 20 carbon atoms. It is more preferable when it has an organic group, and it is still more preferable when it has a methyl group. More preferably, R ¹ does not contain F. Thereby, the adhesiveness with respect to the adjacent layer of the silica-type film obtained comes to be obtained more favorably.

  The resin composition of the present invention more preferably contains an organic solvent containing an aprotic solvent as the component (b). By doing so, a resin composition in which the siloxane resin as the component (a) is sufficiently dissolved or dispersed in the solvent can be obtained. According to such a resin composition, a silica-based film having a uniform and high density and further excellent alkali treatment resistance can be obtained.

  More specifically, the aprotic solvent is preferably at least one solvent selected from the group consisting of ether solvents, ether acetate solvents, ester solvents, and ketone solvents. Further, this aprotic solvent is more preferably one having a boiling point of 80 to 180 ° C. By using these solvents, a silica-based film having a uniform thickness can be easily obtained.

  Furthermore, it is preferable that the resin composition of the present invention further contains a curing accelerating catalyst. By including the curing accelerating catalyst in this manner, the curing of the resin composition proceeds quickly and uniformly, and a denser film can be obtained. As such a curing accelerating catalyst, an onium salt is preferable, and an ammonium salt is more preferable.

  In the resin composition of the present invention, the siloxane resin is more preferably one that can be cured by heat or radiation. In this case, the adhesiveness to the substrate tends to be further improved by forming a chemical bond with the substrate or the like in curing during the formation of the silica-based film.

  Moreover, the manufacturing method of the silica-type film of this invention is characterized by including the process of baking the film | membrane which consists of the said resin composition of this invention. Thus, a silica-type film can be easily obtained by baking the resin composition of the said this invention shape | molded by the film form.

  More specifically, the method for producing a silica-based film of the present invention comprises a step of coating the resin composition of the present invention on a substrate to form a film comprising the resin composition, and at least a solvent from the film. It is more preferable to include a step of removing a part and a step of baking this film at a temperature of 200 to 500 ° C. By these steps, a silica-based film that is denser and has excellent alkali treatment resistance can be obtained.

  Furthermore, this invention provides the silica-type film obtained by the manufacturing method of the said invention. Such a silica-based film is formed from the resin composition of the present invention, so that it is excellent in both resistance to alkali treatment and adhesion to an adjacent layer.

  The silica-based coating of the present invention preferably has a refractive index of 1.42 or less determined at an ellipsometric wavelength of 633 nm. The relative dielectric constant is more preferably 4.0 or less. Furthermore, the Young's modulus measured by the nanoindentation method is particularly preferably 5 GPa or more. Furthermore, it is more preferable that the transmittance of light of 300 to 800 nm is 90% or more. A silica-based film having these characteristics has extremely excellent alkali treatment resistance while maintaining sufficient adhesion to adjacent layers.

  The present invention also provides a laminate comprising a substrate and the silica-based coating of the present invention provided on the substrate. Such a laminated plate can be used for various purposes by changing the configuration of the substrate, and can be applied as a transparent substrate by using a substrate made of a transparent material, for example. It can also be applied as an antireflection film for displays and the like. Furthermore, this invention provides an electronic component provided with the silica-type film of the said invention.

  ADVANTAGE OF THE INVENTION According to this invention, while having the outstanding alkali treatment tolerance, the resin composition which can form the silica-type film which has the outstanding adhesiveness with respect to an adjacent layer can be provided. Moreover, according to this invention, the silica type coating using this resin composition, its manufacturing method, an antireflection film, a transparent substrate, and an electronic component can be provided.

Hereinafter, preferred embodiments of the present invention will be described.
[Silica-based coating]

  First, a silica-based film obtained from the resin composition according to the embodiment of the present invention will be described.

  The silica-based film according to a preferred embodiment has excellent alkali treatment resistance. Here, the resistance to alkali treatment refers to resistance to treatment with an alkali metal hydroxide aqueous solution, and indicates a characteristic that hardly causes deterioration when the aqueous solution comes into contact. Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, and francium hydroxide. The concentration of the alkali metal hydroxide aqueous solution in the evaluation of alkali treatment resistance is generally about 0.1 to 20% by weight, preferably about 1 to 20% by weight, and more preferably about 5 to 10% by weight. Further, the aqueous solution can be heated and used as necessary.

The alkali treatment resistance of the silica-based coating can be confirmed, for example, as follows.
(1) First, a silica-based film is formed, and its film thickness and refractive index are confirmed. Specifically, a silica-based film forming resin composition is placed in a 2 mL plastic syringe, a PTFE (polytetrafluoroethylene) pore diameter 0.20 μm filter is attached to the tip, and 1.5 mL of the resin composition is 5 inches. It is dropped on a silicon wafer and a coating film is formed by spin coating. In the formation of the coating film, the rotation speed is adjusted so that the film thickness of the coating film after curing is 225 ± 25 nm.

Next, using a hot plate, the organic solvent in the coating film was removed at 250 ° C. over 3 minutes, and then the organic solvent was used in a quartz tube furnace in which the oxygen concentration was controlled at around 100 ppm at 350 ° C. over 30 minutes. The coating film after removal is cured to obtain a silica-based film. Then, the obtained silica-based film is irradiated with a He—Ne laser having a wavelength of 633 nm with an ellipsometer L116B manufactured by Gardner, and the film thickness and refractive index of the silica-based film are determined from the phase difference caused by the irradiation.
(2) Next, the silicon wafer on which the silica-based film is formed is immersed in a 10 wt% potassium hydroxide (KOH) aqueous solution heated to 50 ° C. for 10 minutes, and then the silicon wafer is washed with pure water. Spin dry.
(3) Thereafter, the film thickness and refractive index of the silica-based film after immersion in the KOH aqueous solution are determined in the same manner as in the above method (1). And the silica-type film whose film thickness difference before and behind immersion in KOH aqueous solution is 50 nm or less and whose change in refractive index is 0.06 or less is determined to have good alkali treatment resistance.

  As the silica-based film, those having a film thickness difference of preferably 30 nm or less, more preferably 20 nm or less, and particularly preferably 10 μm or less in the above-described determination method are preferable because the alkali treatment resistance is further improved. A silica-based film having a film thickness difference exceeding 50 nm is not preferable from the viewpoint of difficulty in controlling the film thickness. Further, the refractive index difference of the silica-based coating is preferably 0.03 or less, more preferably 0.01 or less, and further preferably 0.006 or less. It is considered that the silica-based film having the refractive index difference exceeding 0.06 is extremely deteriorated in film quality due to alkali treatment.

  When used as an antireflection film, the silica-based film preferably has a refractive index of 1.42 or less, more preferably 1.41 or less, and even more preferably 1.40 or less. When the refractive index exceeds 1.42, the function as an antireflection film tends to be insufficient. The refractive index can be measured by the same method as described above. In addition, when using a silica-type film for uses other than an antireflection film, it does not need to have such a refractive index.

Further, when used as an insulating film, the silica-based film has a relative dielectric constant of preferably 4.0 or less, more preferably 3.6 or less, and further preferably 3.5 or less, 3.4. The following is particularly preferable, and 3.3 or less is more preferable, and 3.0 or less is extremely preferable. If the relative dielectric constant of the silica-based film exceeds 4.0, it has a dielectric constant equivalent to that of a normal SiO ₂ film, and the inter-wiring capacity cannot be reduced, making it difficult to use as an insulating film. In addition, when using a silica-type film for uses other than an insulating film, it does not need to have such a refractive index.

  The relative dielectric constant of the silica-based film can be measured, for example, as follows. First, an interlayer insulating film made of a silica-based film is formed. That is, first, a resin composition for forming a silica-based film is placed in a 2 mL plastic syringe, a PTFE pore size 0.20 μm filter is attached to the tip, 1.5 mL of the resin composition is added, and the resistance is 0.02 Ω · cm. It is dropped on a 5-inch silicon wafer as described below, and a coating film is formed by spin coating. In the formation of the coating film, the rotation speed is adjusted so that the film thickness of the coating film after curing is 225 ± 25 nm.

  Next, using a hot plate, the organic solvent in the coating film was removed at 250 ° C. over 3 minutes, and then the organic solvent was used in a quartz tube furnace in which the oxygen concentration was controlled at around 100 ppm at 350 ° C. over 30 minutes. The coating film after the removal is cured to produce a silica-based film as an interlayer insulating film.

  Thereafter, using a vacuum deposition apparatus, Al metal is vacuum deposited on the silica-based coating so as to have a circular shape with a diameter of 2 mm and a thickness of about 0.1 μm. Thus, an interlayer insulating film having a structure in which a silica-based film is disposed between the Al metal and the silicon wafer (low resistivity substrate) is formed.

A dielectric test fixture (Yokogawa Electric Corporation: HP16451B) is connected to the LF impedance analyzer (Yokogawa Electric Corporation: HP4192A) for the charge capacity of the interlayer insulating film made of the silica-based coating thus obtained. Measured under the conditions of a temperature of 23 ° C. ± 2 ° C., a humidity of 40% ± 10%, and a use frequency of 1 MHz. And the measured value of the obtained charge capacity is expressed by the following formula:
Dielectric constant of interlayer insulating film = 3.597 × 10 ⁻² × charge capacity (pF) × film thickness of interlayer insulating film (μm)
By substituting into, the relative dielectric constant of the interlayer insulating film can be calculated. In addition, as a value of the film thickness of the interlayer insulating film, a value obtained by measuring the film thickness of the silica-based film can be employed.

  Further, the transmittance of light having a wavelength of 300 to 800 nm of the silica-based coating is preferably 90% or more, more preferably 93% or more, still more preferably 95% or more, and 97% or more. And particularly preferred. When the transmittance of light in the above-mentioned wavelength region of the silica-based coating is less than 90%, the visibility tends to deteriorate when this silica-based coating is used as an antireflection film or an interlayer insulating film of an FPD (flat panel display). It is in.

  The light transmittance of such a silica-based film can be measured, for example, as follows. That is, first, a silica-based film is formed in the same manner as described above, except that a substrate that is transparent in the wavelength region of 300 to 800 nm is used instead of a silicon wafer. Next, the substrate on which the silica-based film is formed is used with a UV-visible spectrophotometer (U-3310) manufactured by Hitachi, Ltd., and the substrate on which the silica-based film is not formed is used as a reference for a wavelength of 300 to 800 nm. By measuring the region in the transmittance mode, the transmittance of light in the above-mentioned wavelength region of the silica-based coating can be measured.

Furthermore, the Young's modulus of the silica-based film measured by the nanoindentation method is preferably 5 GPa or more, more preferably 7 GPa or more, further preferably 10 GPa or more, and particularly preferably 15 GPa or more. If the Young's modulus of the silica-based film is less than 5 GPa, for example, the silica-based film may be easily peeled off in a process where stress such as packaging is applied. The Young's modulus of the silica-based film is, for example, after forming an interlayer insulating film in the same manner as described above, and then using nanoindenter SA2 (DCM, manufactured by MTS) at a temperature of 23 ° C. ± 2 ° C. and a frequency of 75 Hz. The Young's modulus can be determined by measuring under a condition that the measurement range is 1/10 or less of the film thickness and does not vary with the indentation depth.
[Resin composition]

  Next, a preferred embodiment of a resin composition for forming a silica-based film will be described. The resin composition for forming a silica-based film contains (a) a siloxane resin and (b) a solvent. Hereinafter, first, each component contained in the resin composition will be described.

［式中、Ｒ^１は、水素及びフッ素のうちのいずれか一方の原子、ホウ素、窒素、アルミニウム、リン、ケイ素、ゲルマニウム若しくはチタンを含む基、又は、炭素数１〜２０の有機基を示し、Ｘは加水分解性基を示し、ｎは０〜２の整数である。ただし、Ｒ^１又はＸが複数存在する場合、これらはそれぞれ同一でも異なっていてもよい。］ (A) Siloxane resin The siloxane resin as the component (a) is obtained by hydrolytic condensation of a raw material component containing a silicon compound represented by the following general formula (1).

[Wherein, R ¹ represents an atom of any one of hydrogen and fluorine, a group containing boron, nitrogen, aluminum, phosphorus, silicon, germanium, or titanium, or an organic group having 1 to 20 carbon atoms, X represents a hydrolyzable group, and n is an integer of 0-2. However, when two or more R < ¹ > or X exists, these may be same or different, respectively. ]

Here, the hydrolysis condensation refers to a reaction in which, after the hydrolyzable group in the silicon compound represented by the above formula (1) is converted into a hydroxy group by hydrolysis, the hydroxy groups cause dehydration condensation. . In the siloxane resin formed by such hydrolysis condensation, a silicon atom is bonded in a linear or three-dimensional network via an oxygen atom, and at least a part of the silicon atom is represented by the above R ^1. It has a structure in which groups are bonded. In addition, as a raw material component, as long as the silicon compound represented by the general formula (1) is included as an essential component, it may further include other components, but from the viewpoint of obtaining a silica-based film having excellent characteristics. Is preferably the majority (90% or more) of the raw material component is a silicon compound of the general formula (1), more preferably the raw material component is composed only of the silicon compound of the general formula (1).

  As the siloxane resin, those having an OH group at the terminal or side chain are preferable. Thereby, in the curing reaction at the time of forming the silica-based film, hydrolysis condensation for curing proceeds better.

  Such a siloxane resin preferably has a weight average molecular weight (Mw) of 500 to 1,000,000 from the viewpoint of solubility in a solvent, mechanical properties, moldability, etc., and is 500 to 500,000. More preferably, it is more preferably 500 to 100,000, particularly preferably 500 to 10,000, and still more preferably 500 to 5,000. If the Mw of the siloxane resin is less than 500, the film formability when forming a silica-based film tends to be inferior. On the other hand, when Mw exceeds 1,000,000, the compatibility with the solvent of the siloxane resin is lowered, and it tends to be difficult to obtain a dense film. In the present specification, Mw means a value measured by gel permeation chromatography (hereinafter referred to as “GPC”) and converted using a standard polystyrene calibration curve.

Such Mw can be measured, for example, by performing GPC under the following conditions.
Sample: Silica-based film forming resin composition Standard polystyrene: Tosoh Corporation standard polystyrene (Molecular weight 190,000, 17,900, 9,100, 2,980, 578, 474, 370, 266)
Detector: RI-monitor manufactured by Hitachi, Ltd., trade name “L-3000”
Integrator: GPC integrator manufactured by Hitachi, Ltd., trade name “D-2200”
Pump: Hitachi, Ltd., trade name “L-6000”
Degassing device: Showa Denko Co., Ltd., trade name "Shodex DEGAS"
Column: Hitachi Chemical Co., Ltd., trade names “GL-R440”, “GL-R430”, “GL-R420” connected in this order and used eluent: tetrahydrofuran (THF)
Measurement temperature: 23 ° C
Flow rate: 1.75 mL / min Measurement time: 45 minutes

  In the silicon compound represented by the above formula (1) which is a raw material component of the siloxane resin, examples of the hydrolyzable group represented by X include an alkoxy group, a halogen atom, an acetoxy group, an isocyanate group, and a hydroxyl group. . In these, an alkoxy group is preferable from a viewpoint of improving the stability and application | coating characteristic of a resin composition.

  Examples of the silicon compound (alkoxysilane) in which the hydrolyzable group represented by X is an alkoxy group include tetraalkoxysilane, trialkoxysilane, and dialkoxysilane. Tetraalkoxysilanes include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetra-iso-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, tetra Examples thereof include phenoxysilane.

  Trialkoxysilanes include trimethoxysilane, triethoxysilane, tri-n-propoxysilane, fluorotrimethoxysilane, fluorotriethoxysilane, fluorotri-n-propoxysilane, methyltrimethoxysilane, methyltriethoxysilane. Methyltri-n-propoxysilane, methyltri-iso-propoxysilane, methyltri-n-butoxysilane, methyltri-iso-butoxysilane, methyltri-tert-butoxysilane, methyltriphenoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane Ethyltri-n-propoxysilane, ethyltri-iso-propoxysilane, ethyltri-n-butoxysilane, ethyltri-iso-butoxysilane, ethyltri-tert- Toxisilane, ethyltriphenoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltri-n-propoxysilane, n-propyltri-iso-propoxysilane, n-propyltri-n-butoxysilane N-propyltri-iso-butoxysilane, n-propyltri-tert-butoxysilane, n-propyltriphenoxysilane, iso-propyltrimethoxysilane, iso-propyltriethoxysilane, iso-propyltri-n-propoxy Silane, iso-propyltri-iso-propoxysilane, iso-propyltri-n-butoxysilane, iso-propyltri-iso-butoxysilane, iso-propyltri-tert-butoxysilane, iso-propyl Liphenoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, n-butyltri-n-propoxysilane, n-butyltri-iso-propoxysilane, n-butyltri-n-butoxysilane, n-butyltri-iso -Butoxysilane, n-butyltri-tert-butoxysilane, n-butyltriphenoxysilane, sec-butyltrimethoxysilane, sec-butyltriethoxysilane, sec-butyltri-n-propoxysilane, sec-butyltri-iso-propoxy Silane, sec-butyltri-n-butoxysilane, sec-butyltri-iso-butoxysilane, sec-butyltri-tert-butoxysilane, sec-butyltriphenoxysilane, t-butyltrimethoxysilane, t- Butyltriethoxysilane, t-butyltri-n-propoxysilane, t-butyltri-iso-propoxysilane, t-butyltri-n-butoxysilane, t-butyltri-iso-butoxysilane, t-butyltri-tert-butoxysilane, t-butyltriphenoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltri-n-propoxysilane, phenyltri-iso-propoxysilane, phenyltri-n-butoxysilane, phenyltri-iso-butoxysilane, phenyl Tri-tert-butoxysilane, phenyltriphenoxysilane, trifluoromethyltrimethoxysilane, pentafluoroethyltrimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 3,3 3- trifluoropropyl triethoxysilane, and the like.

  Further, as dialkoxysilane, methyldimethoxysilane, methyldiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldi-n-propoxysilane, dimethyldi-iso-propoxysilane, dimethyldi-n-butoxysilane, dimethyldi-sec -Butoxysilane, dimethyldi-tert-butoxysilane, dimethyldiphenoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldi-n-propoxysilane, diethyldi-iso-propoxysilane, diethyldi-n-butoxysilane, diethyldi-sec- Butoxysilane, diethyldi-tert-butoxysilane, diethyldiphenoxysilane, di-n-propyldimethoxysilane, di-n-propyldiethoxysilane Di-n-propyldi-n-propoxysilane, di-n-propyldi-iso-propoxysilane, di-n-propyldi-n-butoxysilane, di-n-propyldi-sec-butoxysilane, di-n-propyldi- tert-butoxysilane, di-n-propyldiphenoxysilane, di-iso-propyldimethoxysilane, di-iso-propyldiethoxysilane, di-iso-propyldi-n-propoxysilane, di-iso-propyldi-iso- Propoxysilane, di-iso-propyldi-n-butoxysilane, di-iso-propyldi-sec-butoxysilane, di-iso-propyldi-tert-butoxysilane, di-iso-propyldiphenoxysilane, di-n-butyl Dimethoxysilane, di-n-butyldiethoxy Orchid, di-n-butyldi-n-propoxysilane, di-n-butyldi-iso-propoxysilane, di-n-butyldi-n-butoxysilane, di-n-butyldi-sec-butoxysilane, di-n- Butyldi-tert-butoxysilane, di-n-butyldiphenoxysilane, di-sec-butyldimethoxysilane, di-sec-butyldiethoxysilane, di-sec-butyldi-n-propoxysilane, di-sec-butyldi- iso-propoxysilane, di-sec-butyldi-n-butoxysilane, di-sec-butyldi-sec-butoxysilane, di-sec-butyldi-tert-butoxysilane, di-sec-butyldiphenoxysilane, di-tert -Butyldimethoxysilane, di-tert-butyldiethoxysilane, di- tert-butyldi-n-propoxysilane, di-tert-butyldi-iso-propoxysilane, di-tert-butyldi-n-butoxysilane, di-tert-butyldi-sec-butoxysilane, di-tert-butyldi-tert- Butoxysilane, di-tert-butyldiphenoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, diphenyldi-n-propoxysilane, diphenyldi-iso-propoxysilane, diphenyldi-n-butoxysilane, diphenyldi-sec- Butoxysilane, diphenyldi-tert-butoxysilane, diphenyldiphenoxysilane, bis (3,3,3-trifluoropropyl) dimethoxysilane, methyl (3,3,3-trifluoropropyl) dimethoxysilane, etc. And the like.

  In addition, as the silicon compound (halogenated silane) of the above general formula (1) in which the hydrolyzable group represented by X is a halogen atom (halogen group), the alkoxy group in the alkoxysilane described above is substituted with a halogen atom. The compound which can be illustrated can be illustrated. Moreover, as a silicon compound (acetoxysilane) of the said General formula (1) whose X is an acetoxy group, the compound by which the alkoxy group in the alkoxysilane mentioned above was substituted by the acetoxy group is mentioned. Furthermore, examples of the compound of general formula (1) (isocyanate silane) in which X is an isocyanate group include compounds in which the alkoxy group in the alkoxysilane described above is substituted with an isocyanate group. Furthermore, examples of the compound of the general formula (1) (hydroxysilane) in which X is a hydroxy group include compounds in which the alkoxy group in the alkoxysilane described above is substituted with a hydroxy group. In addition, the compound represented by the said General formula (1) can be used individually or in combination of 2 or more types.

N in the said General formula (1) shows the integer of 0-2. However, when n is 2, each R ¹ may be the same or different. Moreover, when n is 0-2, said X may be same or different, respectively. In addition, it is preferable that n is 0-1, and the compound represented by the general formula (1) in which n is 0 and the compound represented by the general formula (1) in which n is 1 are combined. More preferably it is used. When a compound in which n is 0 and a compound in which n is 1 are combined, the siloxane resin includes a unit represented by SiO ₂ and a unit represented by R ¹ SiO _3/2 . However, ^{R 1} is as defined above. Such a siloxane resin is obtained by cohydrolyzing and condensing the above-mentioned tetraalkoxysilane and trialkoxysilane having polyfunctionality. The unit represented by SiO ₂ is a unit derived from tetraalkoxysilane, and the unit represented by R ¹ SiO _3/2 is a unit derived from trialkoxysilane. Since the siloxane resin contains these structural units, the crosslink density is improved, so that the film characteristics can be improved.

  As described above, the siloxane resin is obtained by hydrolytic condensation of a raw material component containing the silicon compound represented by the general formula (1) as an essential component, and is mainly composed of a polymer of this silicon compound. The This hydrolysis-condensation reaction can be caused, for example, by adding water to a silicon compound or other raw material components and stirring in a solvent. In this hydrolysis condensation reaction, a catalyst for promoting the reaction may be further added. Examples of such a catalyst include an acid catalyst, an alkali catalyst, and a metal chelate compound.

  Examples of the acid catalyst include formic acid, maleic acid, fumaric acid, phthalic acid, malonic acid, succinic acid, tartaric acid, malic acid, lactic acid, citric acid, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid and heptanoic acid. , Octanoic acid, nonanoic acid, decanoic acid, oxalic acid, adipic acid, sebacic acid, butyric acid, oleic acid, stearic acid, linoleic acid, linolenic acid, salicylic acid, benzenesulfonic acid, benzoic acid, p-aminobenzoic acid, p- Examples thereof include organic acids such as toluenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid and trifluoroethanesulfonic acid, and inorganic acids such as hydrochloric acid, phosphoric acid, nitric acid, boric acid, sulfuric acid and hydrofluoric acid. These may be used alone or in combination of two or more.

  Examples of the alkali catalyst include sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, pyridine, monoethanolamine, diethanolamine, triethanolamine, dimethylmonoethanolamine, monomethyldiethanolamine, ammonia, tetramethylammonium. Hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecacilamine, dodecacylamine, cyclopentylamine , Cyclohexylamine, N, N-dimethylamine, N, N-diethylamine, N N-dipropylamine, N, N-dibutylamine, N, N-dipentylamine, N, N-dihexylamine, N, N-dicyclopentylamine, N, N-dicyclohexylamine, trimethylamine, triethylamine, tripropylamine, Examples include tributylamine, tripentylamine, trihexylamine, tricyclopentylamine, and tricyclohexylamine. These may be used alone or in combination of two or more.

  Furthermore, examples of the metal chelate compound include trimethoxy mono (acetyl acetonate) titanium, triethoxy mono (acetyl acetonate) titanium, tri-n-propoxy mono (acetyl acetonate) titanium, tri-iso-propoxy. Mono (acetylacetonate) titanium, tri-n-butoxy mono (acetylacetonate) titanium, tri-sec-butoxy mono (acetylacetonate) titanium, tri-tert-butoxy mono (acetylacetonate) titanium, Dimethoxy mono (acetyl acetonate) titanium, diethoxy di (acetyl acetonate) titanium, di n-propoxy di (acetyl acetonate) titanium, diiso-propoxy di (acetyl acetonate) titanium, di n-butoxy・ Di (acetylacetonate) Chita , Disec-butoxy-di (acetylacetonate) titanium, ditert-butoxy-di (acetylacetonate) titanium, monomethoxytris (acetylacetonate) titanium, monoethoxytris (acetylacetonate) titanium, mono n-propoxy-tris (acetylacetonate) titanium, monoiso-propoxy-tris (acetylacetonate) titanium, mono-n-butoxy-tris (acetylacetonate) titanium, mono-sec-butoxy-tris (acetylacetonate) titanium , Mono tert-butoxy tris (acetylacetonate) titanium, tetrakis (acetylacetonate) titanium, trimethoxy mono (ethyl acetoacetate) titanium, triethoxy mono (ethyl acetoacetate) titanium, tri-n-propoxy (Ethyl acetoacetate) titanium, tri-iso-propoxy mono (ethyl acetoacetate) titanium, tri-n-butoxy mono (ethyl acetoacetate) titanium, tri-sec-butoxy mono (ethyl acetoacetate) titanium, tri -Tert-butoxy mono (ethyl acetoacetate) titanium, dimethoxy mono (ethyl acetoacetate) titanium, diethoxy di (ethyl acetoacetate) titanium, di-n-propoxy di (ethyl acetoacetate) titanium, diiso-propoxy Di (ethyl acetoacetate) titanium, di-n-butoxy di (ethyl acetoacetate) titanium, disec-butoxy di (ethyl acetoacetate) titanium, di tert-butoxy di (ethyl acetoacetate) titanium, monometh Xy-tris (ethyl acetoacetate) titanium, monoethoxy tris (ethyl acetoacetate) titanium, mono n-propoxy tris (ethyl acetoacetate) titanium, monoiso-propoxy tris (ethyl acetoacetate) titanium, mono n- Metal chelates with titanium such as butoxy tris (ethyl acetoacetate) titanium, mono sec-butoxy tris (ethyl acetoacetate) titanium, mono tert-butoxy tris (ethyl acetoacetate) titanium, tetrakis (ethyl acetoacetate) titanium Examples thereof include compounds and compounds in which titanium of the metal chelate compound having titanium is substituted with zirconium, aluminum, or the like. These may be used alone or in combination of two or more.

  The hydrolytic condensation of the silicon compound is preferably performed using the above catalyst. However, when the stability of the composition deteriorates, or when there is a concern about the influence of corrosion on other materials by including the catalyst, for example, The catalyst may be removed from the composition after hydrolysis, or may be reacted to deactivate the function as a catalyst. Although there is no restriction | limiting in particular as these methods, For example, distillation, an ion chromatography column, etc. are mentioned as a method of removing a catalyst. Moreover, you may take out the hydrolyzate of the said silicon compound of General formula (1) from the reaction material after a hydrolysis by reprecipitation etc. On the other hand, as a method of deactivating the function as a catalyst by the reaction, for example, when the catalyst is an alkali catalyst, there are a method of neutralizing by adding an acid catalyst or making the pH acidic.

  The amount of the catalyst used in the hydrolysis condensation is preferably in the range of 0.0001 to 1 mol with respect to 1 mol of the compound represented by the general formula (1). If the amount used is less than 0.0001 mol, the effect of promoting hydrolysis condensation tends to be hardly obtained. On the other hand, when it exceeds 1 mol, undesired gelation tends to be promoted during hydrolysis condensation. In the hydrolysis-condensation reaction, alcohol or the like is generated as a hydrolysis by-product. However, these are protic solvents and are not preferable if they are contained in the resin composition. Therefore, they are removed using an evaporator or the like. It is desirable.

As described above, the siloxane resin in the present embodiment mainly has a structure in which the silicon compound represented by the general formula (1) is bonded in a linear or three-dimensional network via an oxygen atom. . Further, at least part of the silicon atoms in the structure is a group derived from R ¹ in the silicon compound, that is, any one atom of H and F, B, N, Al, P, Si, Ge or It has a group containing Ti or an organic group having 1 to 20 carbon atoms. However, when the amount of F atoms bonded to silicon atoms increases, the adhesion of the silica-based coating tends to decrease. Therefore, in order to obtain strong adhesion, the structure does not include F atoms. It is desirable. Among the above, the silicon atom in the siloxane resin preferably has a group containing H atom, F atom, Si, or an organic group. Thereby, the dielectric properties and mechanical properties of the resulting silica-based coating are improved. In particular, the silicon atom in the siloxane resin preferably has an organic group, and particularly preferably has a methyl group. The type of group bonded to the silicon atom in the siloxane resin can be arbitrarily changed by appropriately selecting the raw silicon compound, and a plurality of types can be combined.

Further, in the siloxane resin, the atom directly bonded to the silicon atom in the group represented by R ¹ per 1 mol of silicon (Si) atom constituting the siloxane bond in the resin, that is, H atom, Total content M of F atom, B atom, N atom, Al atom, P atom, Si atom, Ge atom, Ti atom and C atom (this is a specific bonding atom (R ¹ in the general formula (1)) Is 0.50 to 1.00 mol). That is, in the siloxane resin, a value obtained by dividing the total number of moles of the specific bond atom bonded to the silicon atom constituting the siloxane bond by the total number of moles of silicon atom constituting the siloxane bond, 0.50 to 1.00. In other words, in a siloxane resin, it can also be said that 0.50 to 1.00 of the above atoms are bonded on an average per one silicon atom in the resin.

  When the value of M in the siloxane resin is within the above range, the resulting silica-based thin film has a dense structure and has excellent alkali treatment resistance, as well as sufficient adhesion to adjacent layers. Moreover, excellent mechanical strength can be obtained. On the other hand, when the M is less than 0.50, the resulting silica-based coating has insufficient alkali treatment resistance. On the other hand, when M exceeds 1.00, the adhesiveness with respect to the adjacent layer of a silica-type film will fall. And from the viewpoint of obtaining the above-described effects better, the value of M is preferably 0.55 to 0.90 mol, more preferably 0.60 to 0.80 mol, and 0.62 More preferably, it is -0.75 mol.

Specifically, the value of M described above can be calculated from the charged amount of the compound of the general formula (1), which is a raw material for the siloxane resin. For example:
M = [M1 + (M2 / 2) + (M3 / 3)] / MSi
Can be calculated. In the formula, M1 represents the total number of atoms bonded to a single (only one) Si atom among the specific bonded atoms, and M2 is an atom shared by two silicon atoms among the specific bonded atoms M3 represents the total number of atoms shared by three silicon atoms among the specific bonding atoms, and MSi represents the total number of Si atoms.

  Moreover, as a siloxane resin, one type can be used alone, or two or more types can be used in combination. As such two or more types of combinations, for example, a combination of two or more types of siloxane resins having different weight average molecular weights, or two types obtained by hydrolytic condensation of raw material components having different silicon compounds as essential components The combination of the above siloxane resin is mentioned.

(B) Solvent The component (b) is a solvent that can dissolve the component (a). Examples of the solvent capable of dissolving the component (a) include aprotic solvents and protic solvents. You may contain these individually or in combination of 2 or more types.

  Examples of aprotic solvents include ketone solvents such as acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-iso-propyl ketone, methyl-n-butyl ketone, methyl-iso-butyl ketone, and methyl-n-pentyl. Ketone, methyl-n-hexyl ketone, diethyl ketone, dipropyl ketone, di-iso-butyl ketone, trimethylnonanone, cyclohexanone, cyclopentanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, γ-butyrolactone, Examples thereof include γ-valerolactone. Also, ether solvents such as diethyl ether, methyl ethyl ether, methyl-n-di-n-propyl ether, di-iso-propyl ether, tetrahydrofuran, methyltetrahydrofuran, dioxane, dimethyldioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl Ether, ethylene glycol di-n-propyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl mono-n-propyl ether, diethylene glycol methyl mono-n-butyl ether, diethylene glycol di-n- Propyl ether, diethylene glycol di-n- Chill ether, diethylene glycol methyl mono-n-hexyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol methyl ethyl ether, triethylene glycol methyl mono-n-butyl ether, triethylene glycol di-n-butyl ether, triethylene Glycol methyl mono-n-hexyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetradiethylene glycol methyl ethyl ether, tetraethylene glycol methyl mono-n-butyl ether, diethylene glycol di-n-butyl ether, tetraethylene glycol methyl mono-n -Hexyl ether, tetraethylene glycol di n-butyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol di-n-propyl ether, propylene glycol dibutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol methyl ethyl ether, dipropylene glycol methyl mono -N-butyl ether, dipropylene glycol di-n-propyl ether, dipropylene glycol di-n-butyl ether, dipropylene glycol methyl mono-n-hexyl ether, tripropylene glycol dimethyl ether, tripropylene glycol diethyl ether, tripropylene glycol methyl Ethyl ether, tripropylene glycol methyl Mono-n-butyl ether, tripropylene glycol di-n-butyl ether, tripropylene glycol methyl mono-n-hexyl ether, tetrapropylene glycol dimethyl ether, tetrapropylene glycol diethyl ether, tetradipropylene glycol methyl ethyl ether, tetrapropylene glycol methyl mono -N-butyl ether, dipropylene glycol di-n-butyl ether, tetrapropylene glycol methyl mono-n-hexyl ether, tetrapropylene glycol di-n-butyl ether and the like.

  Furthermore, ester solvents such as methyl acetate, ethyl acetate, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, acetic acid 3-methoxybutyl, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, nonyl acetate, methyl acetoacetate, ethyl acetoacetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl acetate , Diethylene glycol mono-n-butyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, glycol diacetate, methoxytriglycol acetate, propio Acid ethyl, propionic acid n- butyl, propionate i- amyl, diethyl oxalate, an oxalic di -n- butyl and the like.

  Furthermore, ether acetate solvents such as ethylene glycol methyl ether propionate, ethylene glycol ethyl ether propionate, ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, diethylene glycol methyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol- Examples thereof include n-butyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, dipropylene glycol methyl ether acetate, dipropylene glycol ethyl ether acetate and the like.

  Furthermore, acetonitrile, N-methylpyrrolidinone, N-ethylpyrrolidinone, N-propylpyrrolidinone, N-butylpyrrolidinone, N-hexylpyrrolidinone, N-cyclohexylpyrrolidinone, N, N-dimethylformamide, N, N-dimethylacetamide, Examples thereof include N, N-dimethyl sulfoxide.

Among these, an ether solvent, an ether acetate solvent, or a ketone solvent is preferable from the viewpoint of thickening the silica-based film. In particular, from the viewpoint of suppressing coating unevenness and repelling during the formation of a silica-based film, an ether acetate solvent is most preferable, followed by an ether solvent, and then a ketone solvent. Among the ether solvents, dialkyl dihydric alcohol, diester dihydric alcohol, and alkyl ester dihydric alcohol are preferable. Among ester solvents, alkyl acetates are preferred in addition to diesters of dihydric alcohols listed in ether solvents and alkyl esters of dihydric alcohols. More specifically, the solvent is preferably diethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate or cyclohexanone. These are particularly excellent in compatibility with the siloxane resin and tend to particularly improve the mechanical strength of the resulting silica-based coating. These may be used alone or in combination of two or more.

  On the other hand, examples of protic solvents include alcohol solvents such as methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, sec-butanol, t-butanol, n-pentanol, i -Pentanol, 2-methylbutanol, sec-pentanol, t-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, n-octanol 2-ethylhexanol, sec-octanol, n-nonyl alcohol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec-heptadecyl alcohol, phenol, cyclohexane SANOL, methylcyclohexanol, benzyl alcohol, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, and the like.

  Also, ether solvents such as ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol monophenyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-n-hexyl ether, ethoxytri Examples include glycol, tetraethylene glycol mono-n-butyl ether, propylene glycol monomethyl ether, propylene glycol propyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, and tripropylene glycol monomethyl ether.

  Further, ester solvents such as methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate and the like can be mentioned. Of these, alcohol solvents are preferred from the viewpoint of storage stability of the resin composition. In particular, ethanol, isopropyl alcohol, propylene glycol propyl ether, and the like are preferable from the viewpoint of suppressing coating unevenness and repellency. These can be used alone or in combination of two or more.

  Note that a protic solvent typified by alcohol has hydrogen bonded to oxygen having a high electronegativity. For this reason, protic solvent molecules tend to solvate by forming hydrogen bonds with nucleophiles and the like. That is, since the protic solvent easily solvates with the siloxane resin obtained by hydrolyzing the silicon compound of the general formula (1), the solvent molecule becomes an obstacle in the condensation of the siloxane resin and inhibits curing at a low temperature. There is a case. Therefore, when a protic solvent is used, a large amount of solvent may remain in the film immediately after coating, which may increase the film shrinkage rate during curing. On the other hand, an aprotic solvent does not have a hydrogen atom on an element having a high electronegativity, and is considered to have a smaller factor of reaction inhibition than a protic solvent. Therefore, as a solvent, using an aprotic solvent as compared with a protic solvent has a tendency to obtain a silica-based film having a higher density and higher mechanical strength and excellent alkali treatment resistance. .

  For the above reasons, the resin composition according to the present embodiment has an aprotic solvent of 30% by weight or more, preferably 50% by weight or more, more preferably 70% by weight or more based on the weight of the solvent as component (b). More preferably, it is 80% by weight or more, and particularly preferably 90% by weight or more. When the content of the aprotic solvent in the component (b) is small, the film shrinkage rate at the time of curing of the resin composition is increased, and it is difficult to lower the temperature and shorten the time of curing. It is in. Moreover, there exists a possibility that the raise of the dielectric constant of the silica film obtained and the fall of mechanical strength may arise.

  Moreover, it is preferable that the boiling point of the solvent which is (b) component is 80-180 degreeC, It is more preferable that it is 100 degreeC-180 degreeC, It is further more preferable that it is 100-160 degreeC, 120 degreeC-160 It is particularly preferable that the temperature is C. Although the detailed mechanism is not clear, when the boiling point of the solvent is less than 80 ° C. or exceeds 180 ° C., film unevenness such as striation is likely to occur during the formation of the silica-based film, and in the plane immediately after curing. The film thickness tends to be inferior.

  The method for adding the solvent as the component (b) to the resin composition is not particularly limited. For example, the method for adding the solvent as the component (a) when preparing the siloxane resin as the component, Examples include a method of adding after the preparation or exchanging the solvent, a method of taking out only the component (a) after the preparation of the component (a) and mixing this with the component (b). The solvent may contain water in addition to the organic solvent as in the above-described example, but the content of such water is preferably set to such an extent that the properties of the resin composition and the silica-based coating do not deteriorate. .

  The content of the solvent in the resin composition is preferably such that the concentration of the siloxane resin as the component (a) in the resin composition is 3 to 35% by weight, and is an amount that is 5 to 30% by weight. More preferably, the amount is 5 to 25% by weight, even more preferably 5 to 20% by weight, and even more preferably 5 to 15% by weight. When the amount of the solvent is too large and the concentration of the component (a) is less than 3% by weight, it tends to be difficult to form a silica-based film having a desired film thickness. On the other hand, when the amount of the solvent is too small and the concentration of the component (a) exceeds 35% by weight, the film formability of the silica-based film is deteriorated and the stability of the resin composition itself tends to be lowered.

  In view of the stability of the resin composition, the component (b) preferably has water solubility or water solubility properties (water solubility), and is soluble in water and dissolved in water. Although it has both sex, it is preferable. Moreover, it is preferable that (b) component has polarity. When the component (b) does not have polarity, the compatibility with the component (a) tends to be inferior, and the stability of the resin composition may be insufficient. From these viewpoints, when the aprotic solvent does not have solubility in water or water, it is preferable to add a protic solvent in addition to the aprotic solvent.

(C) Curing Accelerating Catalyst The resin composition according to a preferred embodiment includes the above-described (a) siloxane resin and (b) solvent, but the resin composition may be a curing accelerating catalyst (hereinafter referred to as “ It is preferable that (c) component ") is further contained. If it carries out like this, the hardening reaction at the time of forming a silica-type film from a resin composition will arise favorably, and it will become easy to obtain the silica-type film which is more excellent in alkali processing tolerance and adhesiveness.

  The curing accelerating catalyst is different from ordinary photoacid generators and photobase generators, and is preferably different from ordinary onium salts used in these applications. However, those having a curing acceleration catalyst ability in addition to the photoacid generation ability and photobase generation ability can be applied as the curing acceleration catalyst.

Such a curing accelerating catalyst has a unique characteristic that it exhibits activity mainly in the coating film after coating, not in the solution of the resin composition. The curing acceleration catalytic ability of the compound can be confirmed, for example, by the methods shown in the following 1-4.
1. First, a composition comprising the component (a) and the component (b) is prepared.
2. Then: Was applied on a silicon wafer so that the film thickness after baking would be 1.0 ± 0.1 μm, and this was baked at a predetermined temperature for 30 seconds, and then the film thickness of the obtained film was measured. To do.
3. Thereafter, the silicon wafer on which the film was formed was immersed in a 2.38 wt% tetramethylammonium hydroxide (TMAH) aqueous solution at 23 ± 2 ° C. for 30 seconds, washed with water, and dried to reduce the film thickness (thickness of the film). Observe the degree of decrease. Then, the same temperature is observed for a plurality of samples made of the same composition while changing the baking temperature, and the minimum baking temperature at which the change in film thickness before and after immersion in TMAH can be within 20% is defined as the insoluble temperature. To do.
4). After adding the compound whose curing acceleration catalytic ability is to be confirmed to the same composition as 1 in an amount of 0.01% by weight of the component (a), operations 2 and 3 are performed using the obtained composition. The insoluble temperature when the composition is used is determined. And when the insoluble temperature falls by adding the compound which wants to confirm hardening acceleration | stimulation catalytic ability compared with the case where a compound is not added, it determines with the compound having hardening acceleration | stimulation catalytic ability.

  Examples of such a compound (curing promoting catalyst) having a curing promoting catalytic ability include alkali metals such as sodium hydroxide, sodium chloride, potassium hydroxide and potassium chloride, onium salts and the like. These can be added singly or in combination of two or more. Among these, onium salts are preferred from the viewpoint that the resulting silica-based coating film can be reduced in refractive index and mechanical strength, and can further improve the stability of the resin composition. A salt is more preferred.

  Examples of the onium salt having curing acceleration catalytic ability include a salt formed from (c-1) a nitrogen-containing compound and (c-2) at least one of an anionic group-containing compound and a halogen atom. It is done. In the above (c-1) nitrogen-containing compound, the atoms bonded to nitrogen include H atoms, F atoms, B atoms, N atoms, Al atoms, P atoms, Si atoms, Ge atoms, Ti atoms, and C atoms. At least one selected from the group is preferred. Examples of the anionic group of the anionic group-containing compound include a hydroxyl group, a nitrate group, a sulfate group, a carbonyl group, a carboxyl group, a carbonate group, and a phenoxy group.

  Examples of such onium salt compounds include ammonium hydroxide, ammonium fluoride, ammonium chloride, ammonium bromide, ammonium iodide, ammonium phosphate, ammonium nitrate, ammonium borate, ammonium sulfate, ammonium formate, and maleic acid. Ammonium salt, ammonium fumarate, ammonium phthalate, ammonium malonate, ammonium succinate, ammonium tartrate, ammonium malate, ammonium lactate, ammonium citrate, ammonium acetate, ammonium propionate, Ammonium butanoate, ammonium pentanoate, ammonium hexanoate, ammonium heptanoate, ammonium octanoate, nonanoic acid Ammonium salt, ammonium decanoate, ammonium oxalate, ammonium adipate, ammonium sebacate, ammonium butyrate, ammonium oleate, ammonium stearate, ammonium linoleate, ammonium linoleate, ammonium salicylate Benzene sulfonic acid ammonium salt, benzoic acid ammonium salt, p-aminobenzoic acid ammonium salt, p-toluenesulfonic acid ammonium salt, methanesulfonic acid ammonium salt, trifluoromethanesulfonic acid ammonium salt, trifluoroethanesulfonic acid ammonium salt, etc. And ammonium salt compounds.

  As the onium salt, the ammonium moiety of the ammonium salt compound is methylammonium, dimethylammonium, trimethylammonium, tetramethylammonium, ethylammonium, diethylammonium, triethylammonium, tetraethylammonium, propylammonium, dipropylammonium, tripropyl. Examples thereof include ammonium salt compounds substituted with ammonium, tetrapropylammonium, butylammonium, dibutylammonium, tributylammonium, tetrabutylammonium, ethanolammonium, diethanolammonium, triethanolammonium, and the like.

  Among these onium salt compounds, tetramethylammonium nitrate, tetramethylammonium acetate, tetramethylammonium propionate, and tetramethylammonium maleate are particularly effective in promoting curing when forming a silica-based film. Ammonium salts such as tetramethylammonium sulfate are preferred. These can be used singly or in combination of two or more.

  The blending ratio of the curing accelerating catalyst as component (c) is preferably 0.001 to 1.0% by weight and more preferably 0.006 to 1.0% by weight with respect to the total amount of component (a). Preferably, it is 0.06 to 0.5% by weight. When the blending ratio of the curing accelerating catalyst is less than 0.001% by weight, it is difficult to sufficiently obtain the effect of promoting curing at the time of forming the silica film. Storage stability tends to decrease.

  A curing accelerating catalyst such as an onium salt can be added to a desired concentration after being dissolved in water or diluted with water as necessary. Moreover, a hardening acceleration | stimulation catalyst can be added at arbitrary time points, for example, at the time of the start of hydrolysis condensation of the component (a), during hydrolysis condensation, at the end of hydrolysis condensation, or before and after solvent removal after the reaction.

  Although the cause of the effect of adding a curing acceleration catalyst such as an onium salt is not always clear, the curing acceleration catalyst promotes dehydration condensation of the siloxane resin immediately after being applied to a predetermined substrate. It is thought to be caused. This is thought to increase the density of siloxane bonds in the siloxane resin and reduce the residual silanol groups, thereby reducing the film shrinkage and improving the mechanical strength and dielectric properties of the film. However, the action is not limited to this.

(Other ingredients)
In addition to the components (a), (b) and (c), the resin composition of the present embodiment may further contain other components as long as the object and effect of the present invention are not impaired. Examples of other components include dyes, surfactants, silane coupling agents, thickeners, inorganic fillers, thermally decomposable compounds such as polypropylene glycol, and volatile compounds. The thermally decomposable compound and the volatile compound are preferably void-forming compounds that can be decomposed or volatilized by heat (preferably 200 to 500 ° C.) to form voids (hereinafter referred to as “component (d)”), and silica. From the viewpoint of satisfactorily forming voids in the system coating, it is preferable to contain this component (d) in the resin composition. In addition, you may provide void formation ability to the siloxane resin which is (a) component. The resin composition may be a radiation curable composition by containing a photoacid generator or a photobase generator (hereinafter referred to as “component (e)”). These other components are desirably added so as not to impair the effect of suppressing the film shrinkage during the formation of the silica-based film.

  First, the thermally decomposable compound as component (d) will be described.

  The thermally decomposable compound or volatile compound as the component (d) is a compound that thermally decomposes or volatilizes at a heating temperature of 200 to 500 ° C. The component (d) can gradually form micropores (voids and vacancies) in the silica-based film. By the addition of the component (d), the pores can be further refined and the shape can be made uniform during the final curing. In order to satisfactorily exhibit such a function, the component (d) preferably has a reduction rate in a nitrogen gas atmosphere at a temperature of 200 to 500 ° C. of 95% by weight or more, more preferably 97% by weight or more. Preferably, it is 99 weight% or more. When the reduction rate is less than 95% by weight, when the resin composition of this embodiment is heated, decomposition or volatilization of the compound (d) component tends to be insufficient. That is, the component (d) itself, a part of the component (d) or the reaction product derived from the component (d) may remain in the finally obtained silica-based film. In this case, the electrical characteristics of the silica-based film may be easily deteriorated, such as an increase in relative dielectric constant.

Note that the “decrease rate” of the component (d) described above can be obtained, for example, by the following apparatus and conditions. That is, the “decrease rate” is a condition in which 10 mg of the void forming compound as component (d) is set to a temperature rising start temperature of 50 ° C., a temperature rising rate of 10 ° C./min, and a nitrogen (N ₂ ) gas flow rate of 200 ml / min Below, it can measure using a differential scanning calorimeter (Seiko Instruments Inc. make, TG / DTA6300). In this measurement, α-alumina (manufactured by Seiko Instruments Inc.) is used as a reference, and an aluminum open sample pan (manufactured by Seiko Instruments Inc.) having a diameter of 5 mm is used as a sample container.

  In this measurement, the reference mass before the start of decomposition of the component (d) is the mass at 150 ° C. during the temperature increase. This is because the decrease in mass at 150 ° C. or less is due to the removal of adsorbed moisture and the like, and it is estimated that the decomposition of the component (d) itself has not substantially occurred. In addition, in the measurement of the “decrease rate”, when the component (d) is dissolved in a solvent and only the component (d) cannot be directly measured, the solution containing the component (d) is reduced to, for example, a metal petri dish. A residue obtained by taking about 2 g and drying in air at normal pressure at 150 ° C. for 3 hours may be used as a sample.

  The void-forming compound as the component (d) is not particularly limited as long as it has thermal decomposability or volatility. For example, a polymer having a polyalkylene oxide structure, a (meth) acrylate polymer, Examples thereof include polyester polymers, polycarbonate polymers, polyanhydride polymers, and tetrakissilanes. From the viewpoint of suppressing the film shrinkage when forming a silica-based film, it is preferable that the amount of hydroxyl groups (—OH) having a strong interaction with the siloxane resin is small. The thermally decomposable compound and volatile compound containing a hydroxy group (—OH) are solvated with the siloxane resin obtained by hydrolyzing the general formula (1). There is a tendency to inhibit the hardening of. For this reason, the film shrinkage rate during curing tends to increase. However, when there is no polar substituent such as a hydroxy group (—OH), the compatibility with the siloxane resin is lowered, resulting in poor film formation and excessive void size. There is. Therefore, as the void forming compound, those having a certain amount of hydroxy groups are preferable.

  In addition, if the thermally decomposable compound or volatile compound has thermal decomposability or volatility at a temperature lower than 200 ° C., thermal decomposition or volatilization occurs before the siloxane skeleton is formed. The dielectric properties may not be obtained. On the other hand, when the silica-based film is formed on a substrate having a wiring metal or the like if it has thermal decomposability or volatility at a temperature exceeding 500 ° C., the wiring metal may be deteriorated due to the high temperature. is there. Therefore, if it is thermally decomposed or volatilized in these temperature ranges (200 to 500 ° C.), it is possible to obtain an effect that the dielectric characteristics of the insulating film can be easily adjusted while suppressing the deterioration of the wiring metal.

  Examples of the polyalkylene oxide structure include a polyethylene oxide structure, a polypropylene oxide structure, a polytetramethylene oxide structure, a polybutylene oxide structure, and the like. Specific examples of the polymer having such a structure include polyoxyethylene alkyl ether, polyoxyethylene sterol ether, polyoxyethylene lanolin derivative, ethylene oxide derivative of alkylphenol formalin condensate, polyoxyethylene polyoxypropylene block Copolymer, ether type compound such as polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene glycerin fatty acid ester, polyoxyethylene sorbitol fatty acid ester, ether ester type compound such as polyoxyethylene fatty acid alkanolamide sulfate, polyethylene glycol fatty acid ester, Ethylene glycol fatty acid ester, fatty acid monoglyceride, polyglycerin fatty acid ester, sorbitan fatty acid ester, B propylene glycol fatty acid ester ether ester type compounds such like.

  The (meth) acrylate polymer has acrylic acid, methacrylic acid or an ester thereof as a monomer unit. Examples of the acrylic acid ester or methacrylic acid ester include acrylic acid alkyl ester, methacrylic acid alkyl ester, acrylic acid alkoxyalkyl ester, methacrylic acid alkyl ester, and methacrylic acid alkoxyalkyl ester.

  More specifically, examples of the alkyl acrylate ester include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, pentyl acrylate, and acrylic acid. C1-C6 alkylesters, such as hexyl, are mentioned. Moreover, as alkyl methacrylate, it is C1-C1 such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, pentyl methacrylate, hexyl methacrylate. 6 alkyl esters. Further, examples of the alkoxyalkyl acrylate include methoxymethyl acrylate and ethoxyethyl acrylate. Furthermore, examples of the alkoxyalkyl methacrylate include methoxymethyl methacrylate and ethoxyethyl methacrylate.

  Acrylic acid ester or methacrylic acid ester having a hydroxyl group is also suitable, for example, 2-hydroxylethyl acrylate, 2-hydroxylpropyl acrylate, 2-hydroxylethyl methacrylate, 2-hydroxylpropyl methacrylate, and the like. It is done.

  Furthermore, examples of the polyester polymer that is a void forming compound include polycondensates of hydroxycarboxylic acids, ring-opening polymers of lactones, polycondensates of aliphatic polyols and aliphatic polycarboxylic acids, and the like.

  Furthermore, examples of the polycarbonate polymer include polycondensates of carbonic acid and alkylene glycol such as polyethylene carbonate, polypropylene carbonate, polytrimethylene carbonate, polytetramethylene carbonate, polypentamethylene carbonate, and polyhexamethylene carbonate. .

  Examples of the polyanhydride include polycondensates of dicarboxylic acids such as polymalonyl oxide, polyadipoyl oxide, polypimeyl oxide, polysuberoyl oxide, polyazelayl oxide, and polysebacoyl oxide. .

  Further, examples of the tetrakissilanes include tetrakis (trimethylsiloxy) silane, tetrakis (trimethylsilyl) silane, tetrakis (methoxyethoxy) silane, tetrakis (methoxyethoxyethoxy) silane, tetrakis (methoxypropoxy) silane, and the like. As the void-forming compound as the component (d), these can be contained alone or in combination.

  In addition, it is preferable that Mw of (d) component is 200-10,000 from viewpoints, such as solubility to a solvent, compatibility with a siloxane resin, the mechanical property of a film | membrane, and the moldability of a film | membrane, 300- It is more preferably 5,000, and further preferably 400 to 2,000. When this Mw exceeds 10,000, the compatibility with the siloxane resin tends to decrease. On the other hand, if it is less than 200, void formation tends to be insufficient.

  Next, the photoacid generator or photobase generator as component (e) will be described.

  In addition, the photoacid generator or photobase generator as the component (e) is not particularly limited, and examples thereof include the following. Specifically, as the photoacid generator, specifically, a diarylsulfonium salt, a triarylsulfonium salt, a dialkylphenacylsulfonium salt, a diaryliodonium salt, an aryldiazonium salt, an aromatic tetracarboxylic acid ester, an aromatic sulfonic acid ester, Nitrobenzyl ester, oxime sulfonic acid ester, aromatic N-oxyimide sulfonate, aromatic sulfamide, haloalkyl group-containing hydrocarbon compound, haloalkyl group-containing heterocyclic compound, naphthoquinone diazide-4-sulfonic acid ester and the like can be exemplified . These compounds can be used in combination of two or more as required, or in combination with other sensitizers.

［式（２）中、Ｒ^２は炭素数１〜３０の１価の有機基であり、メトキシ基又はニトロ基が置換した芳香族環を含んでいてもよい、Ｒ^３は炭素数１〜２０の１〜４価の有機基、ｍは１〜４の整数である］

［式（３）中、Ｒ^３は一般式（２）と同じであり、Ｒ^４、Ｒ^５は各々独立に炭素数１〜３０の１価の有機基である。Ｒ^４及びＲ^５は互いが結合することにより環状構造を形成していても良い。また、ｍは１〜４の整数である］

［式（４）中、Ｒ^２は一般式（２）と同じであり、Ｒ^６、Ｒ^７は各々独立に炭素数１〜３０の１価の有機基である。Ｒ^６及びＲ^７は、互いが結合することで環状構造を形成していても良い。またどちらか一方は水素原子であってもよい］

［式（５）中、Ｒ^６及びＲ^７は一般式（４）と同じであり、Ｒ^８は炭素数１〜３０の１価の有機基であり、アルコキシ基、ニトロ基、アミノ基、アルキル置換アミノ基、アルキルチオ基が置換した芳香族環を含んでいてもよい。Ｒ^９は、炭素数１〜３０の２価の有機基を示す。］

［式（６）中、Ｒ^１０は炭素数１〜３０の１価の有機基、Ｒ^１１及びＲ^１２は各々独立に水素原子又は炭素数１〜３０の１価の有機基。Ｒ^１３、Ｒ^１４、Ｒ^１５及びＲ^１６は各々独立に炭素数１〜３０の１価の有機基、Ｒ^１７、Ｒ^１８及びＲ^１９は各々独立に単結合又は炭素数１〜３０の２価の有機基、Ｒ^２０及びＲ^２１は各々独立に炭素数１〜３０の３価の有機基、Ｙはアンモニウム塩の対イオンをあらわす。ｍは１〜３であり、ｑ及びｐは各々独立に０、１又は２であり、且つｍ＋ｑ＋ｐ＝３である。］

［式（７）中、Ｒ^１０〜Ｒ^２１、Ｙ、ｍ、ｑ及びｐは一般式（６）と同じである。］ Further, the photobase generator is specifically a nonionic compound group represented by the following general formulas (2) to (5), or nifedipines, etc. Quaternary ammonium salts represented by the formulas (6) and (7) are exemplified.

[In formula (2), R ² is a monovalent organic group having 1 to 30 carbon atoms, a methoxy group or a nitro group may contain an aromatic ring substituted, R ³ is 1 to 20 carbon atoms 1 to 4 valent organic groups, m is an integer of 1 to 4]

[In the formula (3), R ³ is the same as in the general formula (2), and R ⁴ and R ⁵ are each independently a monovalent organic group having 1 to 30 carbon atoms. R ⁴ and R ⁵ may be bonded to each other to form a cyclic structure. M is an integer of 1 to 4]

[In the formula (4), R ² is the same as in the general formula (2), and R ⁶ and R ⁷ are each independently a monovalent organic group having 1 to 30 carbon atoms. R ⁶ and R ⁷ may form a cyclic structure by bonding to each other. Either one may be a hydrogen atom]

[In the formula (5), R ⁶ and R ⁷ are the same as those in the general formula (4), R ⁸ is a monovalent organic group having 1 to 30 carbon atoms, alkoxy group, nitro group, amino group, alkyl group An aromatic ring substituted with a substituted amino group or an alkylthio group may be contained. R ⁹ represents a divalent organic group having 1 to 30 carbon atoms. ]

Wherein ^{(6), R 10} is a monovalent organic ^group, a monovalent organic group of ^{R 11} and ^{R 12} each independently represent a hydrogen atom or a C1-30 C1-30. R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ are each independently a monovalent organic group having 1 to 30 carbon atoms, and R ¹⁷ , R ¹⁸ and R ¹⁹ are each independently a single bond or a divalent group having 1 to 30 carbon atoms. R ²⁰ and R ²¹ each independently represents a trivalent organic group having 1 to 30 carbon atoms, and Y represents a counter ion of an ammonium salt. m is 1 to 3, q and p are each independently 0, 1 or 2, and m + q + p = 3. ]

[In the formula (7), R ^{10 to} R ²¹ , Y, m, q and p are the same as those in the general formula (6). ]

  The amount of the photoacid generator or photobase generator as the component (e) depends on the sensitivity and efficiency, the light source used, the thickness of the desired cured product, and the like. It is preferable to determine appropriately. Specifically, it is preferably 0.0001 to 50% by weight, more preferably 0.001 to 20% by weight, and 0.01 to 10% by weight with respect to the resin component weight of the resin composition. And more preferred. When this addition amount is less than 0.0001% by weight, the photocurability is lowered and the exposure amount required for curing tends to be large. On the other hand, when the amount used exceeds 50% by weight, the stability and film formability of the resin composition tend to be lowered, and the electrical properties and process suitability of the cured product may be lowered.

  Moreover, you may add a photosensitizer to the resin composition which is a radiation curable composition in addition to the said (d) component and (e) component. By using a photosensitizer, the energy of radiation can be efficiently absorbed, and for example, the sensitivity of the photobase generator can be improved. Examples of the photosensitizer include anthracene derivatives, perylene derivatives, anthraquinone derivatives, thioxanthone derivatives, and coumarins.

  Furthermore, you may add a pigment | dye to a resin composition (radiation curable composition). By adding the dye, the sensitivity can be adjusted, and an effect of suppressing the standing wave effect can be obtained. Furthermore, a surfactant, a silane coupling agent, a thickener, an inorganic filler, and the like may be added to the resin composition as long as the object and effects of the present invention are not impaired.

(Content of each component)
Next, the preferable content of each component in the resin composition for forming a silica-based film will be described. The content of the siloxane resin as the component (a) in the resin composition is preferably 3 to 25% by weight. When the concentration of the component (a) exceeds 25% by weight, the amount of the organic solvent becomes relatively small, the film formability at the time of forming the silica-based film is deteriorated, and the stability of the composition itself is also lowered. Tend to. On the other hand, when the concentration of the component (a) is less than 3% by weight, the amount of the solvent is excessive, and it is difficult to form a silica-based film having a desired film thickness. Moreover, the suitable content of (b) component is the total content of (a) component and other components ((c) component, (d) component, (e) component, etc.) in the total amount of the resin composition. The remaining part is removed.

The resin composition for forming a silica-based film according to a preferred embodiment includes the above-described component (a) and component (b) as essential components, and (c) component, (d) component, (e It contains other components such as component). When a silica-based film made of such a resin composition is applied as an interlayer insulating film, it is preferable that the resin composition does not contain an alkali metal or an alkaline earth metal. Even in the case where these are contained, the metal ion concentration in the composition is preferably 100 ppb or less, more preferably 20 ppb or less. When this metal ion concentration exceeds 100 ppb, metal ions easily flow into a semiconductor element having a silica-based film obtained from the resin composition, which may adversely affect device performance. Therefore, when an alkali metal or alkaline earth metal is contained in the resin composition, it is effective to remove the metal from the resin composition by using an ion exchange filter or the like as necessary.
[Method for producing silica-based film]

  Next, a method for producing a silica-based coating using the resin composition for forming a silica-based coating according to the above-described embodiment will be described.

  First, a resin composition is uniformly applied on a predetermined substrate to form a coating film. As the substrate, both a substrate having a flat surface such as a silicon wafer and a substrate having electrodes (wiring metal) or the like and having irregularities (for example, a wiring substrate) can be applied. Examples of the substrate include those made of organic polymers such as polyethylene terephthalate, polyethylene naphthalate, polyamide, polycarbonate, polyacryl, nylon, polyethersulfone, polyvinyl chloride, polypropylene, and triacetyl cellulose. it can. Also, plastic films such as these organic polymers can be used.

  As a method for applying the resin composition on the substrate, a spin coating method is preferable. The coating method is not necessarily limited to the spin coating method, but the spin coating method is preferable because excellent film formability and film uniformity can be obtained.

  In the spin coating method, the resin composition is preferably spin-coated on a substrate such as a silicon wafer at 500 to 5000 revolutions / minute, more preferably 700 to 3000 revolutions / minute to form a coating film. At this time, if the rotational speed is less than 500 revolutions / minute, the uniformity of the film tends to deteriorate. On the other hand, when it exceeds 5000 rpm, the film formability may be deteriorated.

  Under the present circumstances, adjustment of a film thickness can be performed by adjusting the compounding ratio of (a) component in a resin composition, for example. The film thickness can also be adjusted by adjusting the number of rotations and the number of coatings in the spin coating method. When the film thickness is controlled by adjusting the blending ratio of the component (a) as in the former, for example, when the film thickness is increased, the concentration of the component (a) is increased and the film thickness is decreased. Reduces the concentration of component (a). Also, when adjusting the number of rotations and the number of coatings, for example, when increasing the film thickness, the number of rotations is decreased or the number of coatings is increased, while when the film thickness is decreased, the number of rotations is increased. Or reduce the number of applications.

  Next, the organic solvent in the coating film is dried using a hot plate or the like at 50 to 350 ° C., more preferably 100 to 300 ° C., with respect to the obtained coating film. If the drying temperature is less than 50 ° C., the organic solvent tends to be insufficiently dried. On the other hand, when the drying temperature exceeds 350 ° C., for example, when the component (d) is included, the porous component (d) component is thermally decomposed and its volatilization amount before the siloxane skeleton of the siloxane resin is sufficiently formed. Increases undesirably, and it may be difficult to obtain a silica-based film having desired mechanical strength and low dielectric properties.

  Thereafter, the coating film from which the organic solvent has been removed is baked at a heating temperature of 200 to 500 ° C. to perform final curing. This heating temperature is preferably 250 to 500 ° C. In this way, a silica-based film having alkali treatment resistance is formed. The final curing is preferably performed in an inert atmosphere such as nitrogen, argon, or helium. In this case, the oxygen concentration is preferably 1000 ppm or less. When the heating temperature is less than 200 ° C., sufficient curing tends not to be achieved, and decomposition and volatilization of the component (d) tend not to be promoted sufficiently. On the other hand, when the heating temperature exceeds 500 ° C., when there is a metal wiring layer on the substrate, the amount of heat input may increase and the wiring metal may be deteriorated.

  The heating time for this curing is preferably 2 to 60 minutes, more preferably 2 to 30 minutes. If this heating time exceeds 60 minutes, the amount of heat input may increase excessively and the wiring metal may deteriorate. Moreover, as a heating apparatus, a heat treatment apparatus such as a quartz tube furnace, other furnaces, a hot plate, or rapid thermal annealing (RTA) can be used.

  The film thickness of the silica-based film thus formed is preferably 0.01 to 10 μm, for example, for use in an antireflection film, and the film thickness when used for an interlayer insulating film such as an LSI is preferably 0.01 to 2 μm. The film thickness when used in the passivation layer is preferably 2 to 40 μm. The film thickness when used for liquid crystal is preferably 0.1 to 20 μm, the film thickness when used for a photoresist is preferably 0.1 to 2 μm, and the film thickness when used for an optical waveguide is 1 ˜50 μm is preferred. Further, in particular, when an antireflection film is used, a laminated structure may be obtained by combining with a highly refractive material.

  From the viewpoint described above, the thickness of the silica-based coating is preferably from 0.010 to 10 μm, more preferably from 0.01 to 5.0 μm, and further preferably from 0.010 to 3.0 μm. Preferably, it is 0.010-2.0 micrometers, and it is especially preferable that it is 0.10-2.0 micrometers. The film thickness can be adjusted by controlling the film thickness at the application stage of the resin composition described above onto the substrate.

  In addition, in the case of a resin composition that contains a photoacid generator or photobase generator as the component (e) and functions as a radiation curable composition, it was patterned as desired as follows. A silica-based film can also be formed. That is, first, after forming a coating film by applying a resin composition (radiation curable composition) on a predetermined substrate in the same manner as the method for producing a silica-based coating, it is preferably 50 to 200 ° C., more preferably Evaporate the organic solvent and water in the coating film on a hot plate or the like at 70 to 150 ° C. to dry the coating film. When the drying temperature is less than 50 ° C., the organic solvent tends to be not sufficiently volatilized. On the other hand, when the drying temperature exceeds 200 ° C., the coating film is difficult to dissolve in the developer during the subsequent development processing, and the pattern accuracy tends to be lowered.

Next, exposure is performed by irradiating the coating film with radiation through a mask having a desired pattern. Thereby, the exposed part of the coating film irradiated with radiation is cured to form a cured film. Exposure at this time is preferably 5.0~5,000mJ / cm ^2, more preferably 5.0~1,000mJ / cm ^2, is 5.0~500mJ / cm ² Is more preferable, and 5.0 to 100 mJ / cm ² is particularly preferable. If the exposure amount is less than 5.0 mJ / cm ^2, it may be difficult to control depending on the light source. On the other hand, when it exceeds 5,000 mJ / cm ² , the exposure time becomes long, and the productivity tends to deteriorate. In addition, the exposure amount of the conventional general siloxane radiation-curable composition is about 500 to 5,000 mJ / cm ² .

  The radiation used for exposure refers to electromagnetic waves or particle beams, and examples thereof include visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays, and γ-rays. Among these, ultraviolet rays are particularly preferable. Examples of the ultraviolet ray generation source include an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, and an excimer lamp.

  In addition, you may implement a heating (post exposure bake: PEB) process as needed after the said exposure. In the heat treatment in this step, at least an exposed portion (cured film) cured by exposure is heated by a heating means such as a hot plate. In that case, it is preferable to heat in the temperature range in which the solubility with respect to the developing solution of the coating film of an unexposed part does not fall. The heating temperature is preferably 50 to 200 ° C, more preferably 70 to 150 ° C, still more preferably 70 to 110 ° C, and particularly preferably 70 to 100 ° C. In general, the higher the temperature, the more easily the generated acid diffuses, so the lower the heating temperature is better. In addition, the heating temperature in the PEB process of the conventional general siloxane type radiation curable composition is about 115-120 degreeC. However, when it is necessary to reliably avoid acid diffusion and to reduce production costs, it is preferable not to provide a heating step as described above after exposure and before development.

  After the exposure described above, removal of unexposed portions in the coating film of the resin composition (radiation curable composition), that is, development is performed. The unexposed area where the irradiation of radiation is inhibited by the mask in the exposure process has sufficient solubility in the developer used in this development. On the other hand, in the exposed portion irradiated with radiation, an acidic active substance or a basic active substance is generated by exposure, and thereby a hydrolytic condensation reaction occurs in this part, and as a result, the solubility in the developer is lowered. By this action, only the unexposed portion is removed in the development process, and only the exposed portion (cured film) remains selectively on the substrate to form a pattern.

  For development, for example, a developer such as an alkaline aqueous solution can be used. Examples of the alkaline aqueous solution include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and ammonia; primary amines such as ethylamine and n-propylamine; diethylamine and di-n. Secondary amines such as propylamine; tertiary amines such as triethylamine and methyldiethylamine; alcohol amines such as dimethylethanolamine and triethanolamine; fourth amines such as tetramethylammonium hydroxide (TMAH) and tetraethylammonium hydroxide An aqueous solution such as quaternary ammonium can be mentioned. In addition, an aqueous solution obtained by adding an appropriate amount of a water-soluble organic solvent or a surfactant to these alkaline aqueous solutions can also be used. When the resin composition is used for the production of an electronic component, the electronic component tends to hate contamination with alkali metals, and therefore, a tetramethylammonium hydroxide aqueous solution is preferable as the developer.

  The suitable development time depends on the thickness of the coating film and the cured film and the solvent, but is preferably 5 seconds to 5 minutes, more preferably 30 seconds to 3 minutes, and 30 seconds to 1 minute. More preferably it is. If the development time is less than 5 seconds, accurate time control for the entire surface of the wafer or substrate may be difficult, and if it exceeds 5 minutes, the productivity tends to deteriorate. Although the processing temperature at the time of image development is not specifically limited, Generally it is 20-30 degreeC. As the developing method, for example, methods such as spraying, paddle, dipping, and ultrasonic can be applied.

  The pattern thus formed may be rinsed with distilled water or the like as necessary. The pattern in this state (cured film of the resin composition) can be used as it is as a resist mask.

When the cured film patterned by exposure / development described above is left on the substrate or in the electronic component as an interlayer insulating film or a cladding layer, for example, the cured film is baked at a heating temperature of 100 to 500 ° C. It is preferable to perform final curing. This final curing is preferably performed under an inert atmosphere such as N ₂ , Ar, or He, in the air, under reduced pressure conditions, or the like. However, as long as the characteristics required for the application are satisfied, the ambient atmosphere and pressure are increased. There are no particular restrictions on the conditions. By setting the heating temperature in this final curing to 100 ° C. to 500 ° C., the curability of the exposed portion can be further improved and the electrical insulation can be improved. In addition, the lower heating temperature is preferable because deterioration of materials used for the lower layer of the coating film such as a substrate or a wafer tends to be suppressed.

  The heating time in this final curing is preferably 2 to 240 minutes, and more preferably 2 to 120 minutes. If the heating time exceeds 240 minutes, it tends to be undesirable from the viewpoint of mass productivity. Examples of the heating device include a furnace such as a quartz tube furnace, a hot plate, and rapid thermal annealing (RTA).

The silica-based coating as described above is applied to various uses as a single layer or in the form of a laminate provided on a predetermined substrate. For example, it can be applied as an antireflection film by combining with a substrate made of a highly refractive material as described above. In addition, the laminate can be applied as various electronic components and components thereof as described below by changing the type of the substrate.
[Electronic parts]

  Next, an electronic component including the silica-based film according to the above-described embodiment will be described.

  Examples of the electronic component having a silica-based coating include electronic devices such as semiconductor elements and multilayer wiring boards, and flat panel displays (FPD) having a silica-based coating. Silica-based coatings can be used as surface protective films (passivation films), buffer coat films, interlayer insulating films, and the like in semiconductor elements. Moreover, in a multilayer wiring board, it can be suitably used as an interlayer insulating film. Further, in a flat panel display (FPD), it can be used as an insulating film, an interlayer insulating film, a low refractive index film, and a protective film of a transistor. Furthermore, the silica-based film can be used as an antireflection film such as FPD or glass.

  Specifically, as semiconductor elements, individual semiconductor elements such as diodes, transistors, compound semiconductors, thermistors, varistors, thyristors, DRAM (dynamic random access memory), SRAM (static random access memory), EPROM (Erasable Programmable Read Only Memory), Mask ROM (Mask Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), Flash Memory and other Memory Elements, Microprocessor, Theoretical circuit elements such as DSP and ASIC, integrated circuit elements such as compound semiconductors represented by MMIC (monolithic microwave integrated circuit), hybrid integrated circuits (hybrid IC), Diodes, etc. The photoelectric conversion element such as a charge coupled device and the like. Examples of the multilayer wiring board include a high-density wiring board such as MCM. Further, examples of the flat panel display (FPD) include transistors such as liquid crystal, organic EL, and plasma display. Furthermore, other electronic components include optical waveguides, resists, solar battery panels, and the like, and silica-based coatings can be used for these coatings.

  Here, a TFT (thin film transistor) will be described with reference to FIG. 1 as an example of an electronic component having a silica-based film.

  FIG. 1 is a diagram schematically showing a cross-sectional configuration of a main part of a TFT according to a preferred embodiment. The TFT 100 is an electronic component used for a TFT liquid crystal display. In the TFT 100, an undercoat film 2 is formed on a glass substrate 1, and a transistor portion 20 including a source 4, a drain 5, a conductive layer 3, a gate oxide film 6, and a gate electrode 7 is provided on the undercoat film 2. It has the structure which was made. A metal wiring 9 is provided on the transistor portion 20 with the first interlayer insulating film 8 interposed therebetween. A second interlayer insulating film is formed on the metal wiring 9 so as to cover the transistor portion 20 and the metal wiring 9. 10 and the transparent electrode 11 are provided in this order.

The source 4 and the drain 5 in the transistor unit 20 are provided on the undercoat film 2 at a predetermined interval. Further, a conductive layer 3 made of polysilicon is disposed between these source 4 and drain 5 so as to be in contact with both. That is, the source 4 and the drain 5 are disposed so as to sandwich the conductive layer 3 in the in-plane direction. On the conductive layer 3, a gate oxide film 6 made of SiO ₂ is formed so as to cover it, and a gate electrode 7 is further formed on the gate oxide film 6. The gate oxide film 6 prevents the conductive layer 3 and the gate electrode 7 from being in direct contact with each other, and insulation between them is achieved.

  The first interlayer insulating film 8 is formed on the undercoat film 2 so as to cover the transistor portion 20 and has a function of preventing a short circuit. The first interlayer insulating film 8 has an opening so that part of the source 4 and the drain 5 is exposed. The metal wiring 9 is provided on the opening of the first interlayer insulating film 8. The metal wiring 9 has a lead-out portion 9a drawn into the opening, and is connected to the source 4 or the drain 5 by this.

  Further, the second interlayer insulating film 10 is provided so as to cover the lower structure including the metal wiring 9 and has a function of preventing a short circuit. The second interlayer insulating film 10 has an opening in the upper region of the metal wiring 9 connected to the drain 5. A transparent electrode 11 is formed on the second interlayer insulating film 10. The transparent electrode 11 has a lead portion 11 a formed inside the opening of the second interlayer insulating film 10, and is thereby connected to the metal wiring 9 connected to the drain 5.

  In the TFT 100 having the above structure, both the first interlayer insulating film 8 and the second interlayer insulating film 10 are formed by the silica-based film according to the preferred embodiment described above. These first and second interlayer insulating films 8 and 10 can be formed in the same manner as the silica-based film forming method described above. That is, first, a resin composition (radiation curable composition) according to a preferred embodiment of the present invention is applied on a substrate serving as a base by spin coating or the like, and then dried to obtain a coating film. In the case of the first interlayer insulating film 8, the base substrate in this case corresponds to a structure including the substrate 1, the undercoat film 2, and the transistor unit 20, and in the case of the second interlayer insulating film 10, the structure described above. Further, a structure including the first interlayer insulating film 8 and the metal wiring 9 is applicable.

  Next, the coating film is exposed through a mask having a predetermined pattern (a shape covering an area where an opening is to be formed), the portions other than the unexposed portions are cured, and heat treatment is performed as necessary. Then, the unexposed portion is removed by development to form first or second interlayer insulating films 8 and 10 made of a silica-based coating. Thereafter, the silica-based film may be completely cured by further heat treatment as necessary. The first and second interlayer insulating films 8 and 10 may be formed from resin compositions having the same composition, or may be formed from resin compositions having different compositions. Good.

  In the TFT 100 having the above-described configuration, the first and second interlayer insulating films 8 and 10 are composed of the silica-based coating of the present invention having excellent alkali treatment resistance. For this reason, for example, in the manufacture of the TFT 100, even when the patterning of the metal wiring 9 and the transparent electrode 11 is performed by alkali treatment via a resist, the first and second interlayer insulating films 8 and 10 are extremely deteriorated. It is hard to occur. As a result, it is possible to greatly reduce the occurrence of defects such as short circuits in the manufacture of the TFT 100. In addition, since the silica-based coatings that are the first and second interlayer insulating films 8 and 10 are sufficiently excellent in adhesion to adjacent layers, the TFT 100 is extremely resistant to peeling between layers and has excellent durability. And reliability. In the TFT 100, both the first and second interlayer insulating films 8 and 10 are not necessarily formed by the silica-based film of the present invention, and any one of them may be formed, and at least the second interlayer is formed. It is preferable that the insulating film 10 is formed.

  As described above, according to the electronic parts and the like as exemplified above, the silica-based coating film is resistant to alkali treatment, so that it is possible to satisfactorily perform the treatment process with alkali. Furthermore, due to the excellent characteristics of the silica-based film comprising the resin composition for forming a silica-based film of the present invention, it is possible to provide an electronic component having high density, high quality and excellent reliability.

EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to these Examples.
[Example 1]

(Preparation of resin composition)
To a solution obtained by dissolving 5.34 g of tetraethoxysilane and 9.19 g of methyltriethoxysilane in 31.1 g of ethanol, 4.19 g of a 0.644% aqueous nitric acid solution was added dropwise over 1 minute with stirring. After completion of the dropwise addition, the reaction is allowed to proceed for 1.5 hours. Subsequently, 0.21 g of a 2.38% tetramethylammonium nitrate aqueous solution (pH 3.6) is added and dissolved by stirring for 30 minutes at room temperature. A resin composition was prepared.

(Formation of silica-based film (interlayer insulating film))
Using the obtained resin composition, a silica-based film (interlayer insulating film) was formed as shown below. That is, first, the resin composition is taken into a 2 mL plastic syringe, a PTFE pore size 0.20 μm filter is attached to the tip, and 1.5 mL of the resin composition is dropped on a 5-inch silicon wafer, A coating film was formed by spin coating. At this time, in the formation of the coating film, the rotation speed was adjusted so that the film thickness after curing was 225 ± 25 nm. Next, after removing the organic solvent in the coating film at 250 ° C. over 3 minutes, the organic solvent was removed at 350 ° C. for 30 minutes using a quartz tube furnace in which the oxygen concentration was controlled at around 100 ppm. The coating film was finally cured to produce an interlayer insulating film made of a silica-based film.
[Example 2]

(Preparation of resin composition)
To a solution obtained by dissolving 5.34 g of tetraethoxysilane and 9.19 g of methyltriethoxysilane in 31.1 g of isopropanol (IPA), 4.19 g of a 0.644% aqueous nitric acid solution was added dropwise over 1 minute with stirring. . After completion of the dropwise addition, the reaction is allowed to proceed for 1.5 hours. Subsequently, 0.21 g of a 2.38% tetramethylammonium nitrate aqueous solution (pH 3.6) is added and dissolved by stirring for 30 minutes at room temperature. A resin composition was prepared.

(Formation of silica-based film (interlayer insulating film))
Using the obtained resin composition, a silica-based film (interlayer insulating film) was formed in the same manner as in Example 1.
[Example 3]

(Preparation of resin composition)
In a solution prepared by dissolving 10.7 g of tetraethoxysilane and 18.4 g of methyltriethoxysilane in 58.4 g of cyclohexanone (Cy = O), 8.39 g of a 0.644% aqueous nitric acid solution was stirred over 2 minutes. It was dripped. After completion of the dropwise addition, the mixture was allowed to react for 1.5 hours. Subsequently, 4.20 g of a 2.38% tetramethylammonium nitrate aqueous solution (pH 3.6) was added, and the mixture was further stirred for 30 minutes. A part of cyclohexanone was distilled off to obtain 61.7 g of a polysiloxane solution. Next, 38.2 g of cyclohexanone was added, and the mixture was stirred and dissolved at room temperature for 30 minutes to prepare a resin composition for forming a silica-based film.

(Formation of silica-based film (interlayer insulating film))
Using the obtained resin composition, a silica-based film (interlayer insulating film) was formed in the same manner as in Example 1.
[Example 4]

(Preparation of resin composition)
To a solution obtained by dissolving 10.7 g of tetraethoxysilane and 18.4 g of methyltriethoxysilane in 58.4 g of diethylene glycol dimethyl ether (DGDME), 8.39 g of a 0.644% aqueous nitric acid solution was added dropwise over 1 minute with stirring. did. After completion of the dropwise addition, the mixture was allowed to react for 1.5 hours. Subsequently, 4.20 g of a 2.38% tetramethylammonium nitrate aqueous solution (pH 3.6) was added, and the mixture was further stirred for 30 minutes. A part of diethylene glycol dimethyl ether was distilled off to obtain 64.3 g of a polysiloxane solution. Next, 35.7 g of diethylene glycol dimethyl ether was added thereto, and the mixture was stirred and dissolved at room temperature for 30 minutes to prepare a resin composition for forming a silica-based film.

(Formation of silica-based film (interlayer insulating film))
Using the obtained resin composition, a silica-based film (interlayer insulating film) was formed in the same manner as in Example 1.
[Example 5]

(Preparation of resin composition)
In a solution prepared by dissolving 10.7 g of tetraethoxysilane and 18.4 g of methyltriethoxysilane in 62.1 g of propylene glycol monomethyl ether acetate (PGMEA), 8.39 g of a 0.644% nitric acid aqueous solution was stirred for 1 minute. It was dripped over. After completion of the dropwise addition, the mixture was allowed to react for 1.5 hours, followed by addition of 0.423 g of a 2.38% tetramethylammonium nitrate aqueous solution (pH 3.6), and the mixture was further stirred for 30 minutes. A part of propylene glycol monomethyl ether acetate was distilled off to obtain 67.8 g of a polysiloxane solution. Next, 32.2 g of propylene glycol monomethyl ether acetate was added, and the mixture was stirred and dissolved at room temperature for 30 minutes to prepare a resin composition for forming a silica-based film.

(Formation of silica-based film (interlayer insulating film))
Using the obtained resin composition, a silica-based film (interlayer insulating film) was formed in the same manner as in Example 1.
[Example 6]

(Preparation of resin composition)
To a solution obtained by dissolving 26.6 g of methyltriethoxysilane in 65.7 g of propylene glycol monomethyl ether acetate (PGMEA), 7.29 g of a 0.644% aqueous nitric acid solution was added dropwise over 1 minute with stirring. After completion of the dropwise addition, the mixture was allowed to react for 1.5 hours, followed by addition of 0.423 g of a 2.38% tetramethylammonium nitrate aqueous solution (pH 3.6), and the mixture was further stirred for 30 minutes. A part of propylene glycol monomethyl ether acetate was distilled off to obtain 50.8 g of a polysiloxane solution. Next, 49.2 g of propylene glycol monomethyl ether acetate was added, and the mixture was stirred and dissolved at room temperature for 30 minutes to prepare a resin composition for forming a silica-based film.

(Formation of silica-based film (interlayer insulating film))
Using the obtained resin composition, a silica-based film (interlayer insulating film) was formed in the same manner as in Example 1.
[Example 7]

(Preparation of resin composition)
In a solution prepared by dissolving 5.26 g of tetraethoxysilane and 22.5 g of methyltriethoxysilane in 64.0 g of propylene glycol monomethyl ether acetate (PGMEA), 7.83 g of a 0.644% nitric acid aqueous solution was stirred for 1 minute. It was dripped over. After completion of the dropwise addition, the reaction was allowed to proceed for 2 hours, followed by the addition of 0.420 g of a 2.38% tetramethylammonium nitrate aqueous solution (pH 3.6), and stirring for another 2 hours. A part of the monomethyl ether acetate was distilled off to obtain 64.1 g of a polysiloxane solution. Next, 35.9 g of propylene glycol monomethyl ether acetate was added, and the mixture was stirred and dissolved at room temperature for 30 minutes to prepare a resin composition for forming a silica-based film.

(Formation of silica-based film (interlayer insulating film))
Using the obtained resin composition, a silica-based film (interlayer insulating film) was formed in the same manner as in Example 1.
[Example 8]

(Preparation of resin composition)
In a solution obtained by dissolving 7.59 g of tetraethoxysilane and 20.8 g of methyltriethoxysilane in 63.2 g of propylene glycol monomethyl ether acetate (PGMEA), 8.07 g of a 0.644% nitric acid aqueous solution was stirred for 1 minute. It was dripped over. After completion of the dropwise addition, the mixture was allowed to react for 1.5 hours, followed by addition of 0.424 g of a 2.38% tetramethylammonium nitrate aqueous solution (pH 3.6), and after stirring for another 30 minutes, A part of propylene glycol monomethyl ether acetate was distilled off to obtain 60.5 g of a polysiloxane solution. Next, 39.5 g of propylene glycol monomethyl ether acetate was added, and the mixture was stirred and dissolved at room temperature for 30 minutes to prepare a resin composition for forming a silica-based film.

(Formation of silica-based film (interlayer insulating film))
Using the obtained resin composition, a silica-based film (interlayer insulating film) was formed in the same manner as in Example 1.
[Example 9]

(Preparation of resin composition)
In a solution obtained by dissolving 12.2 g of tetraethoxysilane and 17.2 g of methyltriethoxysilane in 61.6 g of propylene glycol monomethyl ether acetate (PGMEA), 8.54 g of a 0.644% nitric acid aqueous solution was stirred for 1 minute. It was dripped over. After completion of the dropwise addition, the mixture was allowed to react for 1.5 hours, followed by addition of 0.423 g of a 2.38% tetramethylammonium nitrate aqueous solution (pH 3.6), and the mixture was further stirred for 30 minutes. A part of propylene glycol monomethyl ether acetate was distilled off to obtain 58.8 g of a polysiloxane solution. Next, 41.2 g of propylene glycol monomethyl ether acetate was added, and the mixture was stirred and dissolved at room temperature for 30 minutes to prepare a resin composition for forming a silica-based film.

(Formation of silica-based film (interlayer insulating film))
Using the obtained resin composition, a silica-based film (interlayer insulating film) was formed in the same manner as in Example 1.
[Example 10]

(Preparation of resin composition)
In a solution prepared by dissolving 13.8 g of tetraethoxysilane and 16.0 g of methyltriethoxysilane in 61.1 g of propylene glycol monomethyl ether acetate (PGMEA), 8.71 g of a 0.644% by weight nitric acid aqueous solution was added while stirring. It was added dropwise over a period of minutes. After completion of the dropwise addition, the reaction was allowed to proceed for 2 hours, followed by addition of 0.420 g of a 2.38 wt% tetramethylammonium nitrate aqueous solution (pH 3.6). A part of glycol monomethyl ether acetate was distilled off to obtain 61.7 g of a polysiloxane solution. Next, 38.3 g of propylene glycol monomethyl ether acetate was added, and the mixture was stirred and dissolved at room temperature for 30 minutes to prepare a resin composition for forming a silica-based film.

(Formation of silica-based film (interlayer insulating film))
Using the obtained resin composition, a silica-based film (interlayer insulating film) was formed in the same manner as in Example 1.
[Comparative Example 1]

(Preparation of resin composition)
In a solution prepared by dissolving 16.9 g of tetraethoxysilane and 13.6 g of methyltriethoxysilane in 60.0 g of propylene glycol monomethyl ether acetate (PGMEA), 9.02 g of a 0.644% by weight nitric acid aqueous solution was added with stirring. It was added dropwise over a period of minutes. After completion of the dropwise addition, the reaction was allowed to proceed for 2 hours. Subsequently, 0.421 g of a 2.38 wt% tetramethylammonium nitrate aqueous solution (pH 3.6) was added, and the mixture was further stirred for 30 minutes. A part of glycol monomethyl ether acetate was distilled off to obtain 66.3 g of a polysiloxane solution. Next, 33.7 g of propylene glycol monomethyl ether acetate was added, and the mixture was stirred and dissolved at room temperature for 30 minutes to prepare a resin composition for forming a silica-based film.

(Formation of silica-based film (interlayer insulating film))
Using the obtained resin composition, a silica-based film (interlayer insulating film) was formed in the same manner as in Example 1.
[Comparative Example 2]

(Preparation of resin composition)
In a solution obtained by dissolving 20.0 g of tetraethoxysilane and 11.3 g of methyltriethoxysilane in 59.0 g of propylene glycol monomethyl ether acetate (PGMEA), 9.34 g of a 0.644% by weight aqueous nitric acid solution was added while stirring. It was added dropwise over a period of minutes. After completion of the dropwise addition, the reaction was allowed to proceed for 2 hours. Subsequently, 0.424 g of a 2.38 wt% tetramethylammonium nitrate aqueous solution (pH 3.6) was added, and the mixture was further stirred for 30 minutes. A part of the glycol monomethyl ether acetate was distilled off to obtain 58.6 g of a polysiloxane solution. Next, 41.4 g of propylene glycol monomethyl ether acetate was added and dissolved by stirring for 30 minutes at room temperature to prepare a resin composition for forming a silica-based film.

(Formation of silica-based film (interlayer insulating film))
Using the obtained resin composition, a silica-based film (interlayer insulating film) was formed in the same manner as in Example 1.
[Comparative Example 3]

(Preparation of resin composition)
In a solution prepared by dissolving 26.9 g of tetraethoxysilane and 5.93 g of methyltriethoxysilane in 56.7 g of propylene glycol monomethyl ether acetate (PGMEA), 10.1 g of a 0.644% by weight aqueous nitric acid solution was added with stirring. It was added dropwise over a period of minutes. After completion of the dropwise addition, the reaction was allowed to proceed for 2 hours. Subsequently, 0.425 g of a 2.38% by weight tetramethylammonium nitrate aqueous solution (pH 3.6) was added, and the mixture was further stirred for 30 minutes. A part of the glycol monomethyl ether acetate was distilled off to obtain 55.3 g of a polysiloxane solution. Next, 44.7 g of propylene glycol monomethyl ether acetate was added, and the mixture was stirred and dissolved at room temperature for 30 minutes to prepare a resin composition for forming a silica-based film.

(Formation of silica-based film (interlayer insulating film))
Using the obtained resin composition, a silica-based film (interlayer insulating film) was formed in the same manner as in Example 1.
[Example 11]

(Preparation of resin composition)
Tetraethoxysilane 74.8g, methyltriethoxysilane 128.7g, photoacid generator (PAI-101, manufactured by Midori Chemical Co., Ltd.) 1.40g and 2.38 wt% tetramethylammonium nitrate aqueous solution (pH 3.6) An aqueous solution prepared by dissolving 0.378 g of 60 wt% nitric acid in 48.6 g of deionized water in a solution obtained by dissolving 0.296 g in 447.3 g of propylene glycol monomethyl ether acetate (PGMEA) was stirred for 3 minutes. And dripped. After the completion of the dropwise addition, the reaction was allowed to proceed for 4 hours, and then part of the produced ethanol and propylene glycol monomethyl ether acetate was distilled off in a 55 ° C. warm bath under reduced pressure to obtain 264.5 g of a polysiloxane solution. To this polysiloxane solution, 85.5 g of propylene glycol monomethyl ether acetate was added and dissolved by stirring at room temperature (25 ° C.) for 30 minutes to prepare a resin composition for forming a silica-based film (radiation curable composition).

(Evaluation of patterning)
Next, patterning (pattern formation) was performed using this resin composition to form a silica-based film having a predetermined pattern. First, 2 mL of the above composition was dropped on the center of a 6-inch silicon wafer, and a coating film was formed on the wafer by spin coating (rotating at 700 rpm for 30 seconds). Dry for 30 seconds above. Then, the i line | wire is 100 mJ / cm with an exposure machine (FPA-3000 iW, Canon Inc.) through the negative mask which has a linear pattern with the minimum line | wire width of 2 micrometers with respect to the dried coating film. ² irradiated. The wafer provided with the coating film after exposure was heated on a hot plate at 100 ° C. for 30 seconds, and then cooled on a cooling plate (23 ° C.) for 30 seconds.

  Then, the wafer was subjected to paddle development for 30 seconds using a 2.38 wt% tetramethylammonium hydroxide (TMAH) aqueous solution as a developer using a coater / developer (Mark 7, manufactured by Tokyo Electron Limited). Was dissolved. Thereafter, the wafer was washed with water and spin-dried. Then, using the furnace body, the spin-dried wafer was heated at 350 ° C. for 30 minutes in a nitrogen atmosphere to form a cured resin composition (silica-based film) having a desired pattern on the wafer. .

  About the pattern shape of the obtained hardened | cured material, when the observation from the upper part by an optical microscope and the cross-sectional shape observation by SEM were performed, the line was formed with sufficient precision. From this, it was confirmed that when the resin composition of Example 11 was used, a pattern accuracy of 2 μm or less was obtained.

(Formation of silica-based film (interlayer insulating film))
A silica-based film was prepared in the same manner as described above except that exposure was performed without using a negative mask and development was not performed (that is, patterning was not performed).
[Characteristic evaluation]

  The refractive index, relative dielectric constant, film thickness, and light transmittance (300 to 800 nm) of the silica-based coating films obtained in Examples 1 to 11 and Comparative Examples 1 to 3 were measured. The film thickness and refractive index were determined by observing the film thickness obtained from the phase difference produced by irradiating the obtained silica-based film with He—Ne laser light and irradiating light at a wavelength of 633 nm. Spectroscopic ellipsometer (manufactured by Gartner; Ellipsometer L116B) ).

  In addition, the silicon wafer having the silica-based film after the above measurement was immersed in a 10 wt% potassium hydroxide (KOH) aqueous solution heated to 50 ° C. for 10 minutes, and then the silicon wafer was washed with pure water. Further spin-dried. Then, the film thickness and refractive index of the silica-based film after such treatment were determined in the same manner as described above. Then, the film thickness change and refractive index change before and after the KOH treatment were calculated from the film thickness and refractive index values before and after immersion in the KOH aqueous solution.

  Refractive index, relative dielectric constant, film thickness, light transmittance (300 to 800 nm), and film thickness change and refractive index change before and after KOH treatment obtained by the silica-based coating of each Example or Comparative Example. The values of are collectively shown in Tables 1-3. In Tables 1 to 3, the value of M (total number of specific bonding atoms) of the siloxane resin contained in the resin composition, the type of solvent (protic or aprotic), the name of the solvent, and the boiling point of the main solvent In addition, the content of the curing accelerating catalyst in the resin composition is also shown.

From Tables 1 to 3, although any silica-based coating had a change in film thickness before and after KOH treatment of less than 50 nm, the silica-based coatings of Examples 1 to 11 were compared with the silica-based coatings of Comparative Examples 1 to 3. The film thickness change before and after the KOH treatment was small. Moreover, the silica-type film of Examples 1-11 had the refractive index change before and behind KOH process remarkably small compared with Comparative Examples 1-3. From this, the silica-type film using the resin composition containing the siloxane resin in which the value of M is between 0.50 and 1.00 has excellent alkali treatment resistance as compared with the other cases. It has been found.
[Example 12]

(Preparation of resin composition)
In a solution obtained by dissolving 3.79 g of tetraethoxysilane and 10.4 g of methyltriethoxysilane in 31.8 g of propylene glycol monomethyl ether acetate (PGMEA), 4.03 g of a 0.644% nitric acid aqueous solution was stirred for 1 minute. It was dripped over. After completion of the dropwise addition, the reaction was allowed for 3.5 hours, and a portion of the produced ethanol and propylene glycol monomethyl ether acetate was distilled off in a warm bath under reduced pressure to obtain 32.8 g of a polysiloxane solution. Next, 17.2 g of propylene glycol monomethyl ether acetate was added, and the mixture was stirred and dissolved at room temperature for 30 minutes to prepare a resin composition for forming a silica-based film.

(Formation of silica-based film (interlayer insulating film))
Using the obtained resin composition, a silica-based film (interlayer insulating film) was formed in the same manner as in Example 1.
[Example 13]

(Preparation of resin composition)
In a solution obtained by dissolving 6.12 g of tetraethoxysilane and 8.60 g of methyltriethoxysilane in 31.0 g of propylene glycol monomethyl ether acetate (PGMEA), 4.28 g of a 0.644% nitric acid aqueous solution was stirred for 1 minute. It was dripped over. After completion of the dropwise addition, the reaction was allowed to proceed for 4 hours, and a portion of the produced ethanol and propylene glycol monomethyl ether acetate was distilled off in a warm bath under reduced pressure to obtain 33.1 g of a polysiloxane solution. Next, 16.9 g of propylene glycol monomethyl ether acetate was added, and the mixture was stirred and dissolved at room temperature for 30 minutes to prepare a resin composition for forming a silica-based film.

(Formation of silica-based film (interlayer insulating film))
Using the obtained resin composition, a silica-based film (interlayer insulating film) was formed in the same manner as in Example 1.
[Example 14]

(Preparation of resin composition)
In a solution prepared by dissolving 6.89 g of tetraethoxysilane and 8.02 g of methyltriethoxysilane in 30.8 g of propylene glycol monomethyl ether acetate (PGMEA), 4.53 g of 0.644% nitric acid aqueous solution was stirred for 1 minute. It was dripped over. After completion of the dropwise addition, the reaction was allowed to proceed for 4 hours, and a portion of the produced ethanol and propylene glycol monomethyl ether acetate was distilled off in a warm bath under reduced pressure to obtain 32.9 g of a polysiloxane solution. Next, 17.1 g of propylene glycol monomethyl ether acetate was added, and the mixture was stirred and dissolved at room temperature for 30 minutes to prepare a resin composition for forming a silica-based film.

(Formation of silica-based film (interlayer insulating film))
Using the obtained resin composition, a silica-based film (interlayer insulating film) was formed in the same manner as in Example 1.
[Comparative Example 4]

(Preparation of resin composition)
In a solution of 8.45 g of tetraethoxysilane and 6.82 g of methyltriethoxysilane dissolved in 30.3 g of propylene glycol monomethyl ether acetate (PGMEA), 4.51 g of a 0.644% nitric acid aqueous solution was stirred for 1 minute. It was dripped over. After completion of the dropwise addition, the reaction was allowed to proceed for 4 hours, and a portion of the produced ethanol and propylene glycol monomethyl ether acetate was distilled off in a warm bath under reduced pressure to obtain 32.7 g of a polysiloxane solution. Next, 17.3 g of propylene glycol monomethyl ether acetate was added, and the mixture was stirred and dissolved at room temperature for 30 minutes to prepare a resin composition for forming a silica-based film.

(Formation of silica-based film (interlayer insulating film))
Using the obtained resin composition, a silica-based film (interlayer insulating film) was formed in the same manner as in Example 1.
[Comparative Example 5]

(Preparation of resin composition)
In a solution prepared by dissolving 9.99 g of tetraethoxysilane and 5.64 g of methyltriethoxysilane in 29.9 g of propylene glycol monomethyl ether acetate (PGMEA), 4.67 g of a 0.644% aqueous nitric acid solution was stirred for 1 minute. It was dripped over. After completion of the dropwise addition, the reaction was allowed to proceed for 4 hours, and a portion of the produced ethanol and propylene glycol monomethyl ether acetate was distilled off in a warm bath under reduced pressure to obtain 32.2 g of a polysiloxane solution. Next, 17.8 g of propylene glycol monomethyl ether acetate was added, and the mixture was stirred and dissolved at room temperature for 30 minutes to prepare a resin composition for forming a silica-based film.

(Formation of silica-based film (interlayer insulating film))
Using the obtained resin composition, a silica-based film (interlayer insulating film) was formed in the same manner as in Example 1.
[Characteristic evaluation]

The refractive index, relative dielectric constant, film thickness, and light transmittance (300 to 800 nm) of the silica coatings obtained in Examples 12 to 14 and Comparative Examples 4 to 5 were measured in the same manner as described above, and KOH The film thickness change and refractive index change before and after the treatment were calculated in the same manner as described above. The results obtained are summarized in Table 4.

  From Table 4, the silica-based coatings of Examples 12-14 all had a film thickness change of 50 nm or less before and after the KOH treatment, whereas the silica-based coatings of Comparative Examples 4-5 were subjected to KOH treatment. All were removed and no silica-based coating was present after the KOH treatment. Further, in the silica-based coatings of Examples 12 to 14, the refractive index change before and after the KOH treatment was substantially within the practical range. From this, the silica-type film using the resin composition containing the siloxane resin in which the value of M is between 0.50 and 1.00 has excellent alkali treatment resistance as compared with the other cases. It became clear.

It is a figure which shows typically the cross-sectional structure of TFT which concerns on embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 2 ... Undercoat film, 3 ... Conductive layer, 4 ... Source, 5 ... Drain, 6 ... Gate oxide film, 7 ... Gate electrode, 8 ... 1st interlayer insulation film, 9 ... Metal wiring, 9a ... Lead-out Part, 10 ... second interlayer insulating film, 11 ... transparent electrode, 11a ... lead-out part, 20 ... transistor part, 100 ... TFT.

Claims (22)

A resin composition for forming a silica-based film,
(A) a siloxane resin obtained by hydrolytic condensation of a raw material component containing a silicon compound represented by the following general formula (1), and (b) a solvent capable of dissolving the component (a).
H atom, F atom, B atom, N atom, Al atom, P atom, Si atom, Ge atom bonded to the silicon atom per mole of silicon atoms constituting the siloxane bond in the siloxane resin, The resin composition, wherein the total content ratio M of atoms selected from the group consisting of Ti atoms and C atoms is 0.50 to 1.00 mol.

[Wherein, R ¹ represents any one atom of H and F, a group containing B, N, Al, P, Si, Ge, or Ti, or an organic group having 1 to 20 carbon atoms, X represents a hydrolyzable group, and n is an integer of 0-2. However, when two or more R < ¹ > or X exists, these may be same or different, respectively. ]   The resin composition according to claim 1, wherein the M is 0.55 to 0.90 mol.   The resin composition according to claim 1, wherein the M is 0.60 to 0.80 mol.   The resin composition according to claim 1, wherein the M is 0.62 to 0.75 mol. The group represented by R ¹ is a group containing H atom, B, N, Al, P, Si, Ge, or Ti, or an organic group having 1 to 20 carbon atoms. The resin composition as described in any one of -4. The group represented by said R < ¹ > is a methyl group, The resin composition as described in any one of Claims 1-5 characterized by the above-mentioned.   The said (b) component is an organic solvent containing an aprotic solvent, The resin composition as described in any one of Claims 1-6 characterized by the above-mentioned.   8. The resin composition according to claim 7, comprising at least one solvent selected from the group consisting of ether solvents, ether acetate solvents, ester solvents and ketone solvents as the aprotic solvent.   The resin composition according to claim 7 or 8, wherein the aprotic solvent has a boiling point of 80 to 180 ° C.   The resin composition according to any one of claims 1 to 9, further comprising a curing accelerating catalyst.   The resin composition according to claim 10, wherein the curing accelerating catalyst is an onium salt.   The resin composition according to claim 10 or 11, wherein the curing accelerating catalyst is an ammonium salt.   The resin composition according to claim 1, wherein the siloxane resin is a resin curable by heat or radiation.   A method for producing a silica-based coating, comprising a step of firing a film comprising the resin composition according to any one of claims 1 to 13. Applying the resin composition according to any one of claims 1 to 13 on a substrate to form a film;
Removing at least a portion of the solvent from the membrane;
Baking the film at a temperature of 200 to 500 ° C .;
A method for producing a silica-based coating, comprising:   A silica-based film obtainable by the production method according to claim 14 or 15.   The silica-based film according to claim 16, wherein the refractive index obtained by ellipsometry at a wavelength of 633 nm is 1.42 or less.   The silica-based film according to claim 16 or 17, wherein a relative dielectric constant is 4.0 or less.   The silica-based film according to any one of claims 16 to 18, wherein Young's modulus measured by a nanoindentation method is 5 GPa or more.   The silica-based film according to any one of claims 16 to 19, wherein the transmittance of light at 300 to 800 nm is 90% or more.   A laminate comprising: a substrate; and the silica-based coating according to any one of claims 16 to 20 provided on the substrate.   An electronic component comprising the silica-based coating according to any one of claims 16 to 20.

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