JP2003137528A - Production method for spherical silica powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method for a spherical silica powder which is improved in the adhesiveness to a resin by increasing the silanol group amount on a powder surface while maintaining high fillability and high fluidity, both of which are advantages of the spherical silica powder, and can enhance the bending strength and a soldering heat resistance of a semiconductor sealing material. SOLUTION: This production method is characterized by reacting the raw material of a spherical silica powder having 0.75 or higher of average sphericity with a hydrolyzate which is obtained by hydrolyzing an alkoxysilane in an acidic region of pH 2 to 5 and is represented by the general formula: Si(OR)4 or RSi(OR)3 (R is an alkyl) in an alkali region of pH 10 or higher to increase the silanol group amount on the surface of the silica powder by 20% or more, and then treating with a silane coupling agent.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing spherical silica powder, and more particularly, to excellent dispersibility and filling property when preparing a resin composition suitable as a sealing material for electronic parts or a resin substrate material. The present invention relates to a method for producing spherical silica powder.

[0002]

2. Description of the Related Art In recent years, semiconductor devices have been becoming lighter, thinner, shorter, smaller and more multifunctional, and high integration has been rapidly progressing. Along with this, resin compositions (semiconductor encapsulating materials) for encapsulating semiconductor elements are also strongly required to have characteristics such as low thermal expansion, high thermal conductivity, low hygroscopicity, and high strength. Also in the field of resin substrates, thinning and multi-layering of resin portions and finer circuit patterns are being advanced, and characteristics such as low thermal expansion and high strength are desired.

At present, the fillers used for semiconductor encapsulation materials are mainly amorphous fused silica powders from the viewpoint of low thermal expansion and high insulation properties, and their particle shapes are also required by semiconductor encapsulation materials. Depending on the characteristics, crushed silica powder, spherical silica powder, or both are used in combination. Then, from the viewpoint of filling the filler as high as possible, many proposals regarding the particle size constitution have been made. For example, Japanese Patent Laid-Open No. 2-173
Japanese Patent No. 155 discloses that spherical silica powder having an average particle diameter of 40 μm or less and crushed silica powder having an average particle diameter of 12 μm or less are used in combination. In addition, JP-A-7-2560
No. 7, globular silica powder is used alone.

The crushed silica powder is obtained by crushing a fused silica ingot to a predetermined particle size, and is excellent in fracture toughness, bending strength, and solder reflow resistance of a semiconductor encapsulating material, but has a square shape, so that it is fluid. It has been pointed out that the property is low, the wire on the surface of the semiconductor element is easily damaged, and the die wear is caused. On the other hand, the spherical silica powder is obtained by injecting silica powder into a high-temperature flame to make it spherical, and is superior in filling property and fluidity to the crushed silica powder and has less problems than the crushed silica powder. However, since the particle surface is smooth and there are relatively few silanol groups, which are reaction points with the resin, the mechanical properties such as fracture toughness and bending strength of the semiconductor encapsulant are smaller than when using crushed silica powder. Become.

[0005]

As a method for improving the mechanical properties of a semiconductor encapsulant filled with spherical silica powder,
For the purpose of enhancing the adhesion between the spherical silica powder and the resin, a method of modifying the surface of the spherical silica powder with various silane coupling agents is used. So far, many findings and proposals regarding this have been made, but since the silane coupling agent reacts with the silanol groups on the surface of the silica powder to perform surface modification, an attempt is made to obtain a more improved effect. Then, after increasing the amount of silanol groups on the surface of silica powder,
Surface treatment is preferable, and the emergence of a new surface treatment method from this viewpoint is earnestly desired.

The present invention has been made in view of the above, and an object thereof is to increase the amount of silanol groups on the surface of a resin while maintaining the high filling property and high fluidity which are advantages of the spherical silica powder. It is an object of the present invention to provide a method for producing spherical silica powder capable of improving adhesion strength with and improving the bending strength and solder heat resistance of a semiconductor encapsulant.

[0007]

[Means for Solving the Problems] That is, the present invention provides a spherical silica powder raw material having an average sphericity of 0.75 or more and a pH of 2
General formula Si obtained by hydrolysis in the acidic region of
(OR) ₄ or RSi (OR) ₃ (where R is an alkyl group) is a hydrolyzate of an alkoxysilane,
A method for producing spherical silica powder, which comprises a step of treating with a silane coupling agent after reacting in an alkaline region of H10 or higher.

In the production method of the present invention, it is preferable to increase the amount of surface silanol groups by 20% or more by the reaction between the spherical silica powder raw material and the hydrolyzate of alkoxysilane.

In addition, the treatment with the silane coupling agent includes a spherical silica powder raw material treated with a hydrolyzate of an alkoxysilane and a silane coupling agent obtained by hydrolyzing in a acidic region of pH 2-5. Hydrolyzate, p
It is preferable that the treatment is carried out in an alkaline region of H10 or higher.

[0010]

The present invention will be described in more detail below.

The average sphericity of the spherical silica powder produced by the present invention is 0.75 or more, preferably 0.85 or more, so that the average sphericity of the surface-treated spherical silica powder raw material is equivalent to that. To use. Here, the average sphericity can be measured using a flow-type particle image analyzer (for example, "FPIA-1000" manufactured by Sysmex Corporation).

That is, when the projected area (A) and the perimeter (PM) of the particle are measured from the particle image and the area of a perfect circle corresponding to the perimeter (PM) is (B), the sphericity of the particle is It can be displayed as A / B. Therefore, assuming a perfect circle with the same perimeter as the perimeter (PM) of the sample particles, PM
= 2πr and B = πr ² , B = π × (PM / 2π) ^{2 and} the sphericity of each particle is sphericity = A / B = A × 4π /
It can be calculated as (PM) ² .

The spherical silica powder produced according to the present invention has a melting rate of 90% or more, particularly 95% in order to reduce the thermal expansion coefficient, the dielectric constant and the dielectric loss of the semiconductor encapsulating material.
%, It is preferable to use a spherical silica powder raw material having a melting rate equivalent to that of the spherical silica powder raw material.

The melting rate is measured by a powder X-ray diffractometer (for example, R
"Mini Flex" manufactured by IGAKU Co., Ltd.
Subjected to X-ray diffraction analysis of a sample in the range 2θ of 26 ° to 27.5 ° of K _alpha line, it can be determined from the intensity ratio of specific diffraction peaks. That is, the crystalline silica is 26.
The main peak exists at 7 °, but it does not exist at this position in fused silica. If fused silica and crystalline silica are mixed, a peak height of 26.7 ° can be obtained according to the ratio of crystalline silica. Therefore, use a calibration curve prepared from samples mixed with crystalline silica adjusted at several ratios. , The mixing ratio of crystalline silica is determined from the X-ray intensity of the sample. Using the obtained mixing ratio,
It is calculated from the equation, melting rate (%) = 100-crystalline silica mixed rate.

The average sphericity or melting rate in the present invention is
The sphericity or melting rate of 100 or more particles arbitrarily selected from the spherical silica powder was measured, and the average value was represented.

The spherical silica powder raw material used in the present invention is obtained by pulverizing powder of silica stone, silica sand, quartz, etc., into a flame or high temperature plasma to be spheroidized, and by gas phase hydrolysis of silicon tetrachloride. Synthesized and spheroidized, spheroidized by using this as a raw material and subjected to firing or flame spraying treatment, spheroidized by synthesizing metal silicon or alkoxysilane as a starting material in the gas phase or liquid phase, and further calcination Or those obtained by subjecting to a flame spraying treatment to make them spherical, etc., and particularly those having an average sphericity of 0.75 or more can be used without restriction.

The spherical silica powder produced by the present invention has an average particle size of 60 μm or less and a specific surface area of 40 m ² /
It is preferably g or less. If the average particle size exceeds 60 μm, the semiconductor chip may be damaged during encapsulation, or a problem of unfilling due to wire flow or clogging may occur. Further, if the specific surface area exceeds 40 m ² / g, it becomes difficult to disperse it uniformly in the semiconductor encapsulating material, which becomes a factor of lowering the resin strength. In particular, when used as a resin substrate material, it is desirable that the maximum particle diameter be 10 μm or less. If the maximum particle size exceeds 10 μm, the appearance of the resin surface may be impaired and the wiring circuit may be damaged.
From this point of view, in the present invention, it is preferable to use a spherical silica powder raw material in which the particle size of the spherical silica powder produced above is adjusted by classification or the like.

The average particle size and the specific surface area in the present invention are the particle size measurement method by the laser scattered light method and B, respectively.
It is a value based on the ET method, and examples of the measuring device include "Cirrus Model 920 type particle sizer" and "Yuasa Ionics Model 4-SORB".

In the method for producing the spherical silica powder of the present invention, a spherical silica powder raw material having an average sphericity of 0.75 or more, preferably 0.85 or more is used, for example, alkoxysilane, water,
After reacting with the hydrolyzate of alkoxysilane, for example, by stirring and mixing in a mixed solution containing an organic solvent and an acid catalyst to coat the surface thereof, preferably after drying, a step of further treating with a silane coupling agent is performed. Go through.

A major feature of the present invention is that a spherical silica powder raw material is reacted with a hydrolyzate of an alkoxysilane to increase the amount of surface silanol groups by 20% or more, preferably 50% or more and then treated with a silane coupling agent. That is. As a result, the dehydration reaction between the silanol groups on the surface of the spherical silica powder and the silane coupling agent is further promoted, so that the mechanical strength of the semiconductor encapsulant can be increased.

The amount of silanol groups on the surface is determined by a Karl Fischer trace moisture measuring device (for example, "CA-0" manufactured by Mitsubishi Chemical Corporation).
5 type "). That is, the sample was heated in an inert gas atmosphere at 250 ° C. to remove the physically adsorbed water, then heated from 250 ° C. to 900 ° C., and the generated water content was measured by an electrotitration method. (Ppm) = {measured water content (μg) / sampled amount (g)}. The rate of increase in the amount of surface silanol groups is determined by the formula: rate of increase in the amount of surface silanol groups (%) = {(amount of surface silanol groups after treatment / amount of surface silanol groups before treatment) -1} × 100 To be

First, the reaction of the alkoxysilane with the hydrolyzate will be described.

Alkoxysilanes have the general formula Si
A compound represented by (OR) ₄ or RSi (OR) ₃ (wherein R is an alkyl group) is used. Above all, it is particularly preferable to use a trifunctional or tetrafunctional alkoxysilane having a hydrolyzable alkoxy group having about 1 to 5 carbon atoms. Considering reactivity, economy, and mass productivity, lower methoxysilane and ethoxysilane are particularly preferable, and tetraethoxysilane is most preferable.

The amount of alkoxysilane used is not particularly limited, but the molar ratio of alkoxysilane: spherical silica powder raw material is preferably 1: 100 or less, more preferably 1:30 or less, and further preferably 1:10. That is, the amount is sufficient to increase the surface silanol group amount of the spherical silica powder raw material by 20% or more before and after the treatment with the alkoxysilane. Although a large amount of alkoxysilane may be added, care should be taken in that case because it may impair economical efficiency and cause aggregation during drying.

The alkoxysilane hydrolyzate is prepared by
Both are mixed in an amount of 4 to 40 mol, preferably 10 mol of water with respect to 1 mol of the alkoxysilane, and an organic solvent is further added. In consideration of drying, it is better that the amount of water is small, but if it is less than 4 mol, hydrolysis may not proceed sufficiently and the silanol groups on the surface of the spherical silica powder may not be sufficiently dehydrated. Moreover, when it exceeds 40 mol, it causes aggregation when removing. Methanol and ethanol are preferable as the organic solvent in consideration of removal after the treatment.
The amount of the organic solvent to be blended may be such that the viscosity of the mixed solution can be lowered, the mixture can be easily stirred, and a uniform treatment can be carried out. It is preferably 40 mol or less.

The hydrolysis reaction of the alkoxysilane in the present invention is carried out at a pH of 2 to 5 by adding an acid catalyst. As the acid catalyst, a volatile inorganic acid or an organic acid having a small number of carbon atoms which is easily removed by decomposition, volatilization, washing or the like after the treatment is preferable, and hydrochloric acid or acetic acid is particularly preferable.

In the production method of the present invention, the reaction of the spherical silica powder raw material with the hydrolyzate of the alkoxysilane is carried out under alkaline conditions of pH 10 or higher in order to accelerate the polycondensation reaction of the hydrolyzate. Its pH
As the adjusting agent, a general water-soluble basic reagent such as aqueous ammonia is used.

The procedure of the above operation is as follows. That is, an acid catalyst is added to water and an organic solvent, the pH value is adjusted to be acidic while being sufficiently mixed at room temperature, and then alkoxysilane is added to cause a hydrolysis reaction. After that, a spherical silica powder raw material is added and dispersed, and in order to adjust the solution to be alkaline, a pH adjusting agent is added and a hydrolyzate of alkoxysilane is reacted with the surface of the spherical silica powder.

The treatment time required for hydrolyzing the alkoxysilane is 0.5 to 1 hour, and the treatment temperature is 10 to 60 ° C.
Is. Further, the treatment temperature for reacting the hydrolyzate of the alkoxysilane on the surface of the spherical silica powder raw material is 10 to 10.
60 ° C, preferably 20-50 ° C, treatment time 0.5-
It is 50 hours, preferably 1 to 24 hours. If the treatment temperature is higher than 60 ° C., the evaporation will be remarkable and uniform treatment will be difficult. Further, if the treatment temperature is lower than 10 ° C., the hydrolysis reaction or the dehydration reaction between the alkoxysilane hydrolyzate and the surface of the spherical silica powder is significantly delayed. If the treatment time is less than 0.5 hours, the spherical silica powder cannot be sufficiently surface-treated.

The spherical silica powder raw material reacted with the hydrolyzate of alkoxysilane is preferably dried after each step of filtration and washing. As a filtration method, a general method such as decantation, suction filtration, and centrifugal separation can be used. The washing is performed using a solvent such as water or alcohol, which can be easily removed by volatilization. Further, the drying is performed by a general method for drying a slurry containing powder, for example, rotary drying, fluidized bed drying, spray drying and the like. As the drying temperature, in consideration of the required time, efficiency, etc., 80 ° C to
200 ° C is practical.

Next, the surface treatment with the silane coupling agent will be described.

The silane coupling agent used in the present invention is selected depending on the kind of resin and desired physical properties. For example, vinyltrichlorosilane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, β (3,4epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ -Glycidoxypropylmethyldiethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β
(Aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-
Phenyl-γ-aminopropyltrimethoxysilane, γ
-Mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane and the like are used.

The amount of silane coupling agent used is
On a mass basis, it is 0.
It is 3 to 5.0 parts, preferably 0.5 to 2.0 parts.
If it is less than 0.3 part, the desired effect cannot be obtained, and if it exceeds 5.0 parts, agglomeration increases, which is not desirable.

As a surface treatment method with a silane coupling agent, a dry method and a wet method can be adopted. The dry method is a method in which a silane coupling agent or a solution obtained by mixing water, an organic solvent, or the like with a silane coupling agent is dropped or sprayed while stirring at high speed using a stirrer such as a Henschel mixer, and then uniformly stirred and mixed and heated and dried. is there. On the other hand, in the wet method, the powder is dispersed in water or an organic solvent to form a slurry, and then a silane coupling agent is added and mixed with stirring.
Alternatively, it is a method in which the powder is dispersed with stirring in a solution prepared by dissolving a silane coupling agent in water or an organic solvent in advance. In the case of the wet method, the surface-treated powder is obtained by removing the solvent by decantation, filtration, centrifugation, etc. and then drying.

The determination as to whether or not the silane coupling agent has been treated with a predetermined amount can be made by measuring the carbon content of the treated spherical silica powder. Specifically, a solvent capable of dissolving the silane coupling agent, for example, acetone is washed several times to remove unreacted silane coupling agent and then dried, and a carbon / sulfur simultaneous analyzer (for example, "CS manufactured by LECO" -444LS type ") to measure the carbon content and calculate the amount of silane coupling agent bonded to the surface of the spherical silica.

Also in the treatment with the silane coupling agent, after the silane coupling agent is hydrolyzed in the acidic region of pH 2 to 5, as in the treatment with the hydrolyzate of the alkoxysilane, the alkaline region of pH 10 or more is used. It is preferable to react under. As the acid catalyst and the pH adjusting agent, the same ones as those used for the treatment with the above-mentioned hydrolyzate of alkoxysilane can be used.

The procedure of the above operation is as follows. That is, an acid catalyst is added to water and an organic solvent, the pH value is adjusted to be acidic while being sufficiently mixed at room temperature, and then a silane coupling agent is added to cause a hydrolysis reaction. After that, a spherical silica powder raw material is added and dispersed, and in order to adjust the solution to be alkaline, a pH adjusting agent is added and a hydrolyzate of the silane coupling agent is reacted with the spherical silica powder surface.

The treatment time required for hydrolyzing the silane coupling agent is 0.5 to 1 hour, and the treatment temperature is 10 to 6
It is 0 ° C. The treatment temperature for reacting the hydrolyzate of the silane coupling agent on the surface of the spherical silica powder raw material is 10 to 60 ° C., preferably 20 to 50 ° C., and the treatment time is 0.5 to 50 hours, preferably 1 ~ 24 hours. If the treatment temperature is higher than 60 ° C., the evaporation will be remarkable and uniform treatment will be difficult. If the treatment temperature is lower than 10 ° C., the hydrolysis reaction or the dehydration reaction between the hydrolyzate of the silane coupling agent and the surface of the spherical silica powder will be significantly delayed.
If the treatment time is less than 0.5 hours, the spherical silica powder cannot be sufficiently surface-treated.

The spherical silica powder produced by the present invention is used as a filler for resins. When mixing the spherical silica powder and the resin, the spherical silica powder produced by the present invention can be used alone or in combination with a normal spherical silica powder or a crushed fused silica powder. It is preferable to use the spherical silica powder of the present invention alone, but for economical reasons, when the crushed fused silica powder is mixed with the spherical silica powder of the present invention, up to about 50% by mass of the silica powder in the filler. It is preferable to stop at. Further, the filling amount of the spherical silica powder produced by the present invention into the resin is preferably 40 to 95% by mass. When the filling amount is less than 40% by mass, the required resin reinforcing effect cannot be obtained.
On the other hand, if it is more than 95% by mass, the moldability and mechanical strength will decrease due to an increase in resin viscosity and generation of voids. Such a resin composition is suitable for a semiconductor sealing material and a resin substrate.

Examples of the resin include epoxy resin, silicone resin, phenol resin, melamine resin, urea resin, unsaturated polyester, fluororesin, polyimide, polyamideimide, polyetherimide and other polyamides, polybutylene terephthalate, polyethylene terephthalate and other polyesters. , Polyphenylene ether, polyphenylene sulfide, wholly aromatic polyester, polysulfone, liquid crystal polymer, polyether sulfone, polycarbonate, maleimide modified resin, ABS resin, AAS (acrylonitrile-acrylic rubber / styrene) resin, AE
S (acrylonitrile / ethylene / propylene / diene rubber-styrene) resin or the like is used.

Among these, the resin for semiconductor encapsulating material is an epoxy resin having two or more epoxy groups in one molecule, and specifically, phenol novolac type epoxy resin, orthocresol novolac type epoxy resin. ,
Epoxidized novolak resin of phenols and aldehydes, bisphenol A type, bisphenol F
Type and bisphenol S type glycidyl ether,
Glycidyl ester acid epoxy resin, linear aliphatic epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin, alkyl-modified polycycle obtained by reacting polybasic acid such as phthalic acid or dimer acid with epochlorohydrin Noh epoxy resin, β-naphthol novolac type epoxy resin,
1,6-dihydroxynaphthalene type epoxy resin, 2,
Examples thereof include 7-hydroxynaphthalene type epoxy resin and bishydroxybiphenyl type epoxy resin. Among them, from the viewpoint of moisture resistance and solder reflow resistance, orthocresol novolac type epoxy resin, bishydroxybiphenyl type epoxy resin, naphthalene skeleton epoxy resin and the like are preferable. Further, for resin substrates, among the above epoxy resins, bisphenol A which is liquid and has low viscosity
Type, bisphenol F type glycidyl ether, etc. are used.

The curing agent for the epoxy resin is not particularly limited as long as it cures by reacting with the epoxy resin, and examples thereof include phenol, cresol, xylenol, resorcinol, chlorophenol, t-butylphenol, nonylphenol, isopropylphenol, octylphenol. Novolak type resins, polyparahydroxystyrene resins, and bisphenol compounds such as bisphenol A and bisphenol S, which are obtained by reacting one or a mixture of two or more selected from, etc. with formaldehyde, paraformaldehyde or paraxylene under an oxidation catalyst. , Trifunctional phenols such as pyrogallol and phloroglucinol, maleic anhydride, acid anhydrides such as phthalic anhydride and pyromellitic anhydride, metaphenylenediamine, diaminodiphenyl Tan, aromatic amines such as diaminodiphenyl sulfone, and the like are used. Furthermore, a curing accelerator can be added to accelerate the reaction between the epoxy resin and the curing agent. As the curing accelerator, 1,
8-diazabicyclo (5,4,0) undecene-7, triphenylphosphine, benzyldimethylamine, 2-
Methyl imidazole and the like.

The following components can be added to the resin composition as required. That is, as a stress reducing agent,
Examples thereof include silicone rubber, polysulfide rubber, acrylic rubber, butadiene rubber, styrene block copolymers, rubber-like substances such as saturated elastomers, and various thermoplastic resins. In addition to the silane coupling agent used for the surface treatment of the spherical silica powder raw material, epoxysilane such as γ-glycidoxypropyltriethoxysilane and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, Aminosilane such as aminopropyltriethoxysilane and N-phenylaminopropylpyrimethoxysilane, hydrophobic silane compounds such as methyltrimethoxysilane and octadecyltrimethoxysilane, titanate coupling agents and aluminum couplings as surface treatment agents. Is. Further, as a flame retardant aid, Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O _{5 and the} like, as a flame retardant, halogenated epoxy resin and phosphorus compound, and as a colorant, carbon black, iron oxide, dye, pigment And so on. It is also possible to add a release agent such as wax.

[0044]

EXAMPLES The present invention will be described more specifically below with reference to examples and comparative examples.

Example 1 To a solution of 920 g of ethanol in 180 g of distilled water was added an appropriate amount of a hydrochloric acid catalyst to adjust the pH to 4.
Adjusted to. To this solution, 208 g of tetraethoxysilane (manufactured by Kanto Chemical Co., Inc.) was dropped little by little, and the mixture was stirred for 30 minutes to carry out a hydrolysis reaction. After that, spherical silica powder (manufactured by Denki Kagaku Kogyo, average particle size 6.2 μm, specific surface area 6.6 m)
² / g, average sphericity 0.89) Add 600 g of raw material, disperse well in the solution, and add ammonia water to bring the solution to pH 1
After adjusting to 2, the mixture was stirred and mixed at room temperature for 24 hours. After the treatment, the solution slurry was suction filtered to remove the solution, and 300 g of ethanol was added to the treated spherical silica powder raw material.
It was washed twice with and dried at 80 ° C. for 24 hours.

Further, 300 g of the obtained tetraethoxysilane-treated spherical silica powder raw material was mixed with 90 g of distilled water,
Ethanol 460 g, N-phenyl-γ-aminopropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd. “KBM-5
73 ") using 4.5 g and adjusting the pH to 4 by the same procedure as above.
To 12 to change the surface treatment to produce spherical silica powder.

<Example 2> 1800 g of spherical silica powder
A spherical silica powder was produced in the same manner as in Example 1 except that the above was adopted.

Example 3 A spherical silica powder was produced in the same manner as in Example 1 except that the amount of N-phenyl-γ-aminopropyltrimethoxysilane added was 13.5 g.

Example 4 Spherical silica was prepared in the same manner as in Example 1 except that 4.5 g of γ-aminopropyltriethoxysilane (“KBE-903” manufactured by Shin-Etsu Chemical Co., Ltd.) was used as the silane coupling agent. A powder was produced.

Example 5 Example 5 was repeated except that 4.5 g of γ-glycidoxypropyltrimethoxysilane (“KBM-403” manufactured by Shin-Etsu Chemical Co., Ltd.) was used as the silane coupling agent. A spherical silica powder was produced.

Comparative Example 1 Spherical silica powder used as a raw material in Examples (manufactured by Denki Kagaku Kogyo Co., Ltd., average particle size 6.2 μm)
m, specific surface area 6.6 m ² / g, average sphericity 0.89).

<Comparative Example 2> Except that the treatment with the hydrolyzate of tetraethoxysilane was omitted and only N-phenyl-γ-aminopropyltrimethoxysilane was treated.
A spherical silica powder was produced in the same manner as in Example 1.

Comparative Example 3 A spherical silica powder was produced in the same manner as in Example 1 except that only the treatment with a hydrolyzate of tetraethoxysilane was carried out and the surface treatment with a silane coupling agent was omitted.

<Comparative Examples 4 and 5> Examples except that the tetraethoxysilane or the silane coupling agent was hydrolyzed with a solution of pH 4 and then the pH value of the solution was adjusted to 4 or 2 and the surface treatment was performed. A spherical silica powder was produced in the same manner as in 1.

With respect to the obtained spherical silica powder, the rate of increase in the amount of surface silanol groups after the tetraethoxysilane treatment,
(1) Carbon content after treatment with silane coupling agent,
(2) The average sphericity was measured. The results are shown in Table 1 (Examples) and Table 2 (Comparative Examples).

Further, in order to evaluate the characteristics of the obtained spherical silica powder as a filler for a semiconductor encapsulating material, 85 parts by weight of spherical silica powder, a biphenyl type epoxy resin (“Epicoat manufactured by Japan Epoxy Resin Co., Ltd.” YX-
4000 ") 6.5 parts, orthocresol novolac type epoxy resin (" EOCN-1020 "manufactured by Nippon Kayaku Co., Ltd.)
3.0 parts, phenol novolac resin ("PSM-4261" manufactured by Gunei Chemical Co., Ltd., 5.0 parts, triphenylphosphine 0.1 part, ester wax 0.3 part, carbon black 0.1 part, silane coupling agent After blending 0.3 parts by a mixer, roll kneading at 100 ° C., cooling and crushing to obtain a semiconductor encapsulating material, and (3)
The fluidity, (4) bending strength, and (5) solder heat resistance (number of cracks) were measured. The results are shown in Tables 1 and 2.

(1) Carbon content 10 g of spherical silica powder was added to 100 g of acetone to obtain 30
Stir for minutes. After that, the slurry is separated into spherical silica powder and acetone by a centrifugal separator, and the supernatant solution of acetone is discarded. This washing operation with acetone is performed 3 times and dried at 70 ° C. for 1 hour. Next, the amount of carbon in 0.5 g of the washed fine spherical silica powder was measured by a carbon / sulfur simultaneous analyzer "CS-444LS type" (manufactured by LECO) and quantified by a calibration curve method.

(2) Average sphericity It was measured by the above method.

(3) Fluidity (spiral flow) Using a spiral flow mold, the spiral flow was measured according to EMMI-66. Molding temperature is 175 ℃,
The molding pressure was 7.4 MPa.

(4) Bending strength The semiconductor sealing material is 3 mm × 5 mm × at a mold temperature of 180 ° C.
It was molded into a size of 80 mm, post-cured at 180 ° C. for 6 hours, and then measured in accordance with the bending strength measurement method of JIS K6911.

(5) Solder heat resistance (number of cracks generated) After obtaining 16 44-pin QFP moldings (packages) encapsulating simulated elements under the condition of 175 ° C. × 2 minutes by low pressure transfer molding method, 175 ° C. × 5 hours post cure was performed. After leaving these for 96 hours under the conditions of temperature 85 ° C. and humidity 85 RH%, they were immersed in solder at 260 ° C. for 10 seconds, and the number of internal cracks observed in 16 molded bodies was confirmed by an ultrasonic probe imager. Examined.

[0062]

[Table 1]

[0063]

[Table 2]

[0064]

Industrial Applicability The spherical silica powder produced by the production method of the present invention has an average sphericity of 0.75 or more so that the average sphericity is not deteriorated before and after the surface treatment. The treatment effect of the silane coupling agent is enhanced because the amount of the silane coupling agent is treated. As a result, even if the spherical silica powder produced by the production method of the present invention alone or in combination with the crushed silica powder is highly filled in the resin, its high filling property and high fluidity are maintained, so that the semiconductor The heat resistance reliability of the sealing material and the like can be significantly improved.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Misaki Yamamoto             2-24-16 Nakamachi, Koganei City, Tokyo             Inside the university graduate school (72) Inventor Kazuyoshi Ikeda             1 Shinkaimachi, Omuta City, Fukuoka Prefecture             Ceremony company Omuta factory (72) Inventor Akira Kobayashi             1 Shinkaimachi, Omuta City, Fukuoka Prefecture             Ceremony company Omuta factory (72) Inventor Hideaki Nagasaka             1 Shinkaimachi, Omuta City, Fukuoka Prefecture             Ceremony company Omuta factory F term (reference) 4G072 AA25 BB05 BB07 GG01 GG03                       HH14 HH30 MM01 QQ06 UU01

Claims (3)

[Claims] 1. A spherical silica powder raw material having an average sphericity of 0.75 or more and a general formula Si (OR) ₄ or RSi (OR) ₃ (provided that R is obtained by hydrolyzing in the acidic region of pH 2 to 5). Is a hydrolyzate of an alkoxysilane represented by the formula (1) is an alkyl group) in the alkaline range of pH 10 or higher, and then the step of treating with a silane coupling agent is included. 2. The method for producing spherical silica powder according to claim 1, wherein the amount of surface silanol groups is increased by 20% or more by the reaction between the raw material of spherical silica powder and a hydrolyzate of alkoxysilane. 3. The treatment with the silane coupling agent,
A spherical silica powder raw material treated with a hydrolyzate of an alkoxysilane and a hydrolyzate of a silane coupling agent obtained by hydrolyzing in an acidic region of pH 2 to 5 were treated with a pH of 1
The process for producing a spherical silica powder according to claim 1 or 2, wherein the treatment is carried out in an alkaline region of 0 or more.