JP2019182715A - Amorphous silica powder, resin composition, and semiconductor encapsulation material - Google Patents

Abstract

To provide an amorphous silica powder in which ground products hardly aggregate each other, which is suitable for a resin composition for semiconductor encapsulation material.SOLUTION: There is provided an amorphous silica powder having average particle diameter of 2 to 50 μm, Al content in terms of oxide of 500 to 3000 ppm, and Si content in terms of oxide of 99.0 mass% or more, average particle diameter of the amorphous silica powder in a particle size range of 3 to 60 μm which is a particle size range A of 5 to 50 μm, and Al content in terms of oxide of 500 ppm or less, and average particle diameter of the amorphous silica powder in a particle size range of 0.01 to 2 μm which is a particle size range B of 0.025 to 1.000 μm, and Al content in terms of oxide of 10000 to 50000 ppm.SELECTED DRAWING: None

Description

  The present invention relates to amorphous silica powder, a resin composition, and a semiconductor encapsulant.

  In recent years, in response to demands for smaller and lighter electronic devices and higher performance, the internal structure of semiconductors has been rapidly reduced in terms of device thickness, gold wire diameter, long span, wiring pitch density, etc. It is progressing. When such a semiconductor is sealed using a semiconductor sealing material having a high viscosity, defects such as gold wire deformation, gold wire cutting, inclination of a semiconductor element, narrow gap unfilling, and the like are increased.

  Therefore, a method for controlling the filler composition, particle size, particle size distribution, etc. in the resin composition constituting the semiconductor sealing material is widely known in order to reduce the viscosity of the semiconductor sealing material and increase the fluidity. . For example, Patent Document 1 discloses a resin composition produced by mixing spherical silica particles having a particle size of 30 to 500 nm with a content of 0.5 to 10% by mass into a resin.

Japanese Patent Laid-Open No. 2015-78080

  As a semiconductor sealing material, a method is known in which a pulverized product obtained by pulverizing a kneaded product of a resin composition is used in a tablet form or in powder form. Among the above, when used in powder form, conventional resin compositions for semiconductor encapsulating materials such as those described in Patent Document 1 have a handleability due to aggregation of the pulverized products when stored at room temperature. There was a decline.

  In view of the above, an object of the present invention is to provide an amorphous silica powder suitable for a resin composition for a semiconductor encapsulant, in which pulverized products are less likely to aggregate.

  The resin composition used for the semiconductor encapsulant mainly contains an epoxy resin, a phenol resin curing agent, a curing accelerator, and the like. When such a resin composition is heated to about 150 ° C. to 200 ° C., which is a general thermosetting temperature (molding temperature), the proton of the phenol resin curing agent is extracted by the curing accelerator, and the epoxy resin and the phenol resin curing agent are extracted. The anionic polymerization chain reaction proceeds with thermosetting.

  On the other hand, the inventors of the present invention have previously described, for example, “—O—Si—O—Al” in the structure of “—O—Si—O—Si—O—Si—O—” of the amorphous silica powder. When a part of Al is substituted at the Si position as in “—O—Si—O—”, the substitution site becomes a strong solid acid point due to the difference between the coordination number of Si and the coordination number of Al. I have found that.

  When the Al-substituted amorphous silica powder is contained in the resin composition and heated, protons coordinated at the solid acid sites are released. This proton is bound to the anionic polymerization terminal, and as a result of the polymerization chain reaction being temporarily stopped, it is considered that the phenomenon that the thermosetting reaction in the resin composition is delayed occurs. That is, the Al-substituted amorphous silica powder can delay the thermosetting reaction of the resin in the encapsulant, and can prepare an encapsulant excellent in fluidity and viscosity characteristics during molding. It is considered possible.

  On the other hand, even if it is the sealing material excellent in the fluidity | liquidity at the time of shaping | molding as mentioned above, and a viscosity characteristic, when it preserve | saved at normal temperature, the pulverized material might aggregate. The present inventors conducted various studies on this cause, and found that the silane coupling agent added in order to increase the affinity between the resin and the filler (amorphous silica powder) does not cause any aggregation between the pulverized products. I guessed it had an impact.

Based on the above knowledge, the present inventors have earnestly developed an amorphous silica powder that can make the pulverized resin compositions less likely to aggregate while having excellent fluidity and viscosity characteristics during molding. As a result of examination, especially in the amorphous silica powder divided into the micron-sized region A and the submicron-sized region B, the Al content in the region B is larger than that in the region A, thereby improving the aggregation between the pulverized products. Has been found to have a significant effect.
That is, the present invention is as follows.

[1] An amorphous silica powder having an average particle diameter of 2 to 50 μm, an Al content of 500 to 3000 ppm in terms of oxide, and an Si content of 99.0% by mass or more in terms of oxide. And
The average particle size of the amorphous silica powder in the particle size range of 3 to 60 μm which is the particle size range A is 5 to 50 μm and the Al content is 500 ppm or less in terms of oxide,
Amorphous silica powder having an average particle size of 0.025 to 1.000 μm and an Al content of 10,000 to 50,000 ppm in terms of oxides in a particle size range of 0.01 to 2 μm in the particle size range B .
[2] The amorphous silica powder according to [1], having an average sphericity of 0.85 or more.
[3] The amorphous silica powder according to [1] or [2], wherein the total content of U and Th is 20 ppb or less.
[4] A resin composition comprising the amorphous silica powder according to any one of [1] to [3] and a resin.
[5] A semiconductor encapsulant using the resin composition according to [4].

  ADVANTAGE OF THE INVENTION According to this invention, the pulverized material cannot aggregate easily and can provide the amorphous silica powder suitable for the resin composition for semiconductor sealing materials. Moreover, the semiconductor sealing material using the resin composition containing the amorphous silica powder has excellent fluidity and viscosity characteristics at the time of molding that are equal to or higher than those of the conventional one.

[1. Amorphous silica powder]
The amorphous silica powder according to the embodiment of the present invention (this embodiment) has an average particle diameter of 2 to 50 μm, an Al content of 500 to 3000 ppm in terms of oxide, and an Si content of oxide. And 99.0% by mass or more.
Hereinafter, the oxide-equivalent Al content may be referred to as “oxide-equivalent Al amount”, and the oxide-equivalent Si content may be referred to as “oxide-equivalent Si amount”.

  When the average particle size is less than 2 μm and exceeds 50 μm, the resin composition thickens when mixed with a resin and deteriorates moldability. The average particle size is preferably 10 to 40 μm, and more preferably 15 to 30 μm.

  If the Al content is less than 500 ppm in terms of oxide, a sufficient ion adsorption effect cannot be obtained. That is, the effect of suppressing the coupling between the coupling agents by intentionally adsorbing the ionic liquid crosslinking to the filler at the solid acid point cannot be obtained. If it exceeds 3000 ppm, the aluminum layer on the amorphous silica powder becomes thick and the effect as a solid acid cannot be obtained. The Al content is preferably 600 to 2000 ppm, and more preferably 700 to 1900 ppm.

  If the Si content is less than 99.0% in terms of oxide, the target thermal expansion coefficient and elasticity may not be obtained, which is incompatible.

  About the amorphous silica powder of this embodiment, it divides into two area | regions of the particle size range A of 3-60 micrometers, and the particle size range B of 0.01-2 micrometers, and prescribes | regulates the oxide conversion Al amount in each. Among these, especially, the region B is a region focused on achieving both the curability and the aggregation prevention, and the effect of the present invention is exhibited by defining the ratio of oxide equivalent Al in this region. There is a meaning.

The average particle diameter of the amorphous silica powder in the particle size range A of 3 to 60 μm is 5 to 50 μm, preferably 10 to 40 μm. When the average particle diameter is less than 5 μm, the fluidity is lowered, and when it exceeds 50 μm, the mixing of coarse particles increases.
Further, the amount of Al in terms of oxide in the amorphous silica powder is 500 ppm or less, and preferably 10 to 400 ppm. When it exceeds 500 ppm, curability will fall.

The average particle diameter of the amorphous silica powder in the particle size range B of 0.01 to 2 μm is 0.025 to 1.000 μm, and preferably 0.030 to 0.450 μm. If the average particle size is less than 0.025 μm, the viscosity increases, and if it exceeds 1.000 μm, the fluidity is lowered.
Moreover, the oxide conversion Al amount in the said amorphous silica powder is 10,000-50000 ppm, and it is preferable that it is 20000-35000 ppm. If the amount of Al in terms of oxide is less than 10,000, sufficient adsorptivity with an ionic substance cannot be obtained, the affinity between silica and resin is lowered, and long-term storage stability is lowered. When the amount of Al in terms of oxide exceeds 50000 ppm, the aluminum layer on the amorphous silica powder becomes thick and the effect as a solid acid cannot be obtained.

Here, of the particle diameters, the average particle diameter of the whole and the average particle diameter of the particle size range A are, for example, a particle diameter (median diameter) in which the cumulative weight in the particle size distribution is 50% by a laser type particle size distribution measuring device. ). Moreover, the average particle diameter of the particle size range B can be calculated | required from a BET specific surface area, for example.
The content of Al in terms of oxide can be measured by, for example, an atomic absorption photometer or ICP, but is preferably measured by an atomic absorption photometer.

  The average sphericity of the amorphous silica powder of this embodiment is preferably 0.85 or more, and more preferably 0.87 or more. When the average sphericity is 0.85 or more, no thickening occurs even when mixed with a resin, and good moldability is obtained. The average sphericity can be measured by an image analysis apparatus such as FPIA-3000.

  Here, the adjustment of the oxide-equivalent Al amount in the amorphous silica powder in the particle size range A and the particle size range B, the oxide-equivalent Al amount and the oxide-equivalent Si amount in the entire particle size range is performed in the raw material powder of each particle size range. The oxide-converted Al amount and the oxide-converted Si amount can be adjusted, or the supply amount of the raw material powder having various average particle diameters to the flame can be adjusted. The average particle diameter, particle size distribution and average sphericity of the amorphous silica powder can be adjusted by adjusting the average particle diameter of the raw material powder and the supply amount to the flame.

  The total content of U (uranium) and Th (thorium) in the amorphous silica powder of the present embodiment is preferably 20 ppb or less, and more preferably 5 ppb or less. When the total of these contents is 20 ppb or less, the generation amount of α-rays derived from radioactive substances is reduced, and rewriting of the storage memory can be suppressed. These contents can be measured by ICP-mass. In order to set the total content of these components to 20 ppb or less, when preparing the raw material powder, the content rate is measured in advance and a material having a content of 20 ppb or less is used.

The specific surface area of the amorphous silica powder (BET specific surface area) is preferably 1 to 10 m ² / g, more preferably 2~7m ² / g.

  The amorphous siliceous powder according to this embodiment preferably has an amorphous ratio measured by the following method of 95% or more. The amorphous ratio is determined by X-ray diffraction analysis using a powder X-ray diffractometer (for example, trade name “D2 PHASER” manufactured by BRUKER) in the range of 26 ° to 27.5 ° of CuKα ray 2θ. Measured from the peak intensity ratio. In the case of silica powder, crystalline silica has a main peak at 26.7 °, but amorphous silica has no peak. When amorphous silica and crystalline silica are mixed, a peak height of 26.7 ° corresponding to the ratio of crystalline silica can be obtained, so the X-ray of the sample relative to the X-ray intensity of the crystalline silica standard sample From the intensity ratio, the crystalline silica mixture ratio (X-ray diffraction intensity of the sample / X-ray diffraction intensity of the crystalline silica) is calculated, and the formula, amorphous ratio (%) = (1-crystalline silica mixture ratio) Obtain the amorphous ratio from x100.

  The amorphous silica powder of the present embodiment is subjected to flame treatment by injecting raw material powder into a high-temperature flame of 2000 ° C. or higher formed by combustible gas and auxiliary combustion gas, for example, classification treatment as required Manufactured to go.

Examples of the raw material powder include a combination of a silica source powder and an aluminum source powder. Here, as the raw material powder, for example, a mixed powder A in which a silica raw powder and an aluminum raw powder are mixed so as to have an oxide equivalent Al amount of 500 ppm or less at a particle size corresponding to the particle size region A, or a particle size region B There is a mixed powder B in which the silica raw powder and the aluminum raw powder are mixed so that the oxide equivalent Al amount becomes 10,000 to 50,000 ppm at a particle size corresponding to the above. The mixed powder A is subjected to a flame treatment, and separately from this, the mixed powder B is subjected to a flame treatment, and then a predetermined amount thereof is mixed to obtain a desired amorphous silica powder.
The powders A and B may be mixed in advance and supplied to the high temperature flame, or may be separately supplied to the high temperature flame.
In addition, according to the above method, the average particle diameter, the oxide-equivalent Al amount and the oxide-equivalent Si amount of the amorphous siliceous powder obtained are the average particle diameter of the raw material powder, and the oxide-equivalent Al amount derived from the raw material. In addition, it is almost the same as the oxide-converted Si amount.

  As the silica source powder, high-purity silica stone, high-purity silica sand, quartz, quartz and other silica-containing mineral powders produced naturally; high-purity silica powder produced by a synthetic method such as precipitated silica and silica gel; it can. In consideration of cost and availability, silica powder is preferable. Silica powder having various particle sizes pulverized by a pulverizer such as a vibration mill or a ball mill is commercially available, and a silica powder having a desired average particle size may be appropriately selected.

  Examples of the aluminum source powder include aluminum oxide, aluminum hydroxide, aluminum sulfate, aluminum chloride, and an aluminum organic compound, but since the aluminum oxide is close to the melting point of the silica source powder, the raw material siliceous powder when sprayed from the burner It is preferable because it is easily fused to the surface of the metal and has a small impurity content.

  As a method of performing flame treatment and classifying as necessary, for example, a furnace body provided with a burner and having a collection device connected thereto is used. The furnace body may be an open type or a closed type, or a vertical type or a horizontal type. The collection device is provided with one or more of a gravity settling chamber, a cyclone, a bag filter, an electric dust collector, etc., and collects amorphous silica powder classified to a desired particle size by changing the collection conditions. be able to. An example of this is the apparatus described in JP-A-11-57451, JP-A-11-71107, etc. When mixing raw material powder during the flame treatment, two or more burners are provided. It is preferable to make a simple design change.

  As the combustible gas for generating a high temperature flame, hydrocarbon gases such as acetylene, ethylene, propane and butane; gaseous fuels such as LPG and LNG; liquid fuels such as kerosene and heavy oil can be used. As the auxiliary combustion gas, oxygen, oxygen-rich cooling gas, and air can be used.

  The particle size range A and the particle size range B can be separated by dispersing the obtained amorphous siliceous powder in pure water and performing sedimentation separation. Measurement can be performed with the separated supernatant side as the particle size range B and the sedimentation portion as the particle size range A.

[2. Resin composition]
The resin composition according to the present embodiment includes the amorphous silica powder of the present invention and a resin. The content of the amorphous silica powder in the resin composition is preferably 10 to 95% by mass, and more preferably 30 to 90% by mass.

  Examples of the resin include epoxy resins, silicone resins, phenol resins, melamine resins, urea resins, unsaturated polyesters, fluororesins, polyimides such as polyimide, polyamideimide, and polyetherimide; polyesters such as polybutylene terephthalate and polyethylene terephthalate; polyphenylene sulfide , Aromatic polyester, polysulfone, liquid crystal polymer, polyethersulfone, polycarbonate, maleimide modified resin, ABS resin, AAS (acrylonitrile-acrylic rubber / styrene) resin, AES (acrylonitrile / ethylene / propylene / diene rubber / styrene) resin are used. can do.

  Among these, in order to prepare a semiconductor sealing material, an epoxy resin having two or more epoxy groups in one molecule is preferable. As epoxy resins, biphenyl type epoxy resins, phenol novolac type epoxy resins, orthocresol novolac type epoxy resins, epoxidized phenol and aldehyde novolak resins, glycidyl ethers such as bisphenol A, bisphenol F and bisphenol S, Glycidyl ester acid epoxy resin, linear aliphatic epoxy resin, cycloaliphatic epoxy resin, heterocyclic epoxy resin, alkyl-modified polyfunctional obtained by reaction of polybasic acid such as phthalic acid and dimer acid with epochlorohydrin Epoxy resin, β-naphthol novolak type epoxy resin, 1,6-dihydroxynaphthalene type epoxy resin, 2,7-dihydroxynaphthalene type epoxy resin, bishydroxybiphenyl type epoxy resin, and further imparts flame retardancy Epoxy resins obtained by introducing a halogen such as bromine for. Among these, from the viewpoint of moisture resistance and solder reflow resistance, biphenyl type epoxy resins, orthocresol novolac type epoxy resins, bishydroxybiphenyl type epoxy resins, naphthalene skeleton epoxy resins and the like are preferable.

When the resin is an epoxy resin, the resin composition of the present embodiment preferably includes an epoxy resin curing agent, or an epoxy resin curing agent and an epoxy resin curing accelerator.
Examples of the epoxy resin curing agent include, for example, various phenolic resins; one or more selected from the group of phenol, cresol, xylenol, resorcinol, chlorophenol, t-butylphenol, nonylphenol, isopropylphenol, octylphenol, and the like. A novolak resin obtained by reacting a mixture with formaldehyde, paraformaldehyde or paraxylene under an oxidation catalyst; polyparahydroxystyrene resin; bisphenol compounds such as bisphenol A and bisphenol S; trifunctional phenols such as pyrogallol and phloroglucinol ; Acid anhydrides such as maleic anhydride, phthalic anhydride and pyromellitic anhydride; aromatic amines such as metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone Down; and the like can be given.
In order to accelerate the reaction between the epoxy resin and the curing agent, the above-described curing accelerator can be used. Examples of the curing accelerator include triphenylphosphine, benzyldimethylamine, 2-methylimidazole and the like.

The resin composition of the present embodiment may further contain the following components as necessary.
That is, as a low stress agent, silicone rubber, polysulfide rubber, acrylic rubber, butadiene rubber, rubbery substances such as styrene block copolymers and saturated elastomers, various thermoplastic resins, resinous substances such as silicone resins, Is a resin in which a part or all of an epoxy resin or a phenol resin is modified with amino silicone, epoxy silicone, alkoxy silicone, or the like; as a silane coupling agent, γ-glycidoxypropyltrimethoxysilane, β- (3,4- Epoxy cyclohexyl) Epoxy silanes such as ethyltrimethoxysilane, aminopropyltriethoxysilane, ureidopropyltriethoxysilane, aminosilanes such as N-phenylaminopropyltrimethoxysilane, phenyltrimethoxysilane, methyltrimeth Hydrophobic silane compounds such as xylsilane and octadecyltrimethoxysilane, mercaptosilanes, etc .; Zr chelates, titanate coupling agents, aluminum coupling agents, etc. as surface treatment agents, flame retardants, halogenated epoxy resins, phosphorus compounds, etc .; As flame retardant aids, Al (OH) ₃ , Mg (OH) ₂ etc .; as colorants, carbon black, iron oxide, dyes, pigments, etc .; and as mold release agents, natural waxes, synthetic waxes, direct Metal salts of chain fatty acids, acid amides, esters, paraffins and the like.

  The resin composition of the present embodiment is obtained by blending a predetermined amount of each of the above materials with a blender, a Henschel mixer, etc., then cooling and pulverizing what is kneaded with a heating roll, kneader, uniaxial or biaxial extruder, etc. Can be manufactured.

[3. Semiconductor encapsulant]
The semiconductor sealing material according to the present embodiment uses the resin composition of the present invention.
Specifically, first, the resin composition is kneaded while being heated with a roll or an extruder, and the kneaded product is stretched into a sheet and cooled. Thereafter, the semiconductor encapsulant is obtained as a pulverized product by pulverizing or extruding the kneaded product in a linear shape and cutting it while cooling. About this pulverized material, it is good also as a fine granular semiconductor sealing material which arranged the tablet shape shape | molded in the column shape, and particle size and shape.

In order to seal the semiconductor using the semiconductor sealing material of the present embodiment, a conventional molding means such as a transfer molding method or a compression molding method is employed.
For example, in order to seal by transfer molding using the semiconductor sealing material according to the present embodiment, a tablet-shaped semiconductor sealing material is loaded into a pot provided in a mold attached to a transfer molding machine and heated. After being melted, it is hardened and sealed by applying pressure and further heating with a plunger.
In the compression mold, the resin composition particles are placed directly on a mold, and the molten molding material is molded by slowly applying pressure to the substrate.

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

[Physical properties of various powders]
Various physical properties of the amorphous silica powder, the amorphous silica powder A, and the amorphous silica powder B were measured and determined as follows.

(Average particle diameter of amorphous silica powder and amorphous silica powder A)
Measurement was performed using a laser particle size distribution analyzer: Cilas 920.

(BET specific surface area of amorphous silica powder and amorphous silica powder B)
Measurement was performed using “Macsorb HM model-1208” (manufactured by MACSORB).

(Average particle diameter of amorphous silica powder B)
The average particle diameter of the powder B was determined from the BET specific surface area of the amorphous silica powder B.

(Al content in terms of oxide in amorphous silica powder, amorphous silica powder A and amorphous silica powder B)
A sample solution obtained by decomposition and concentration using hydrofluoric acid and perchloric acid was quantified with an atomic absorption photometer to calculate the Al content in terms of oxide.

(Si content in terms of oxide in amorphous silica powder, amorphous silica powder A and amorphous silica powder B)
Decomposition and drying were performed using hydrofluoric acid and sulfuric acid, and the Si content in terms of oxide was calculated from the weight of the residue.

(Average sphericity)
Measurement was performed using a powder image analyzer (FPIA-3000). After the sample is dispersed in pure water, the liquid is allowed to flow in a plane extension flow cell, and 100 or more amorphous silica powders moving in the cell are recorded as an image with an objective lens. The average circularity was calculated from equation (1). In the formula (1), HD represents the equivalent diameter of the circular phase, and is obtained from the ratio of the projected area of the target particle to the area of the perfect circle. PM represents the projected perimeter of the target particle. The average value of 200 amorphous silica powders calculated in this way was defined as the average circularity.
Formula (1): Average circularity = π · HD / PM
From this average circularity, the average sphericity was determined by the formula: average sphericity = (average circularity) ² .

(Total content of U and Th)
The content rate of U and Th was measured by quantifying the sample solution thermally decomposed using hydrofluoric acid and nitric acid with an inductively coupled plasma mass spectrometer.

[Example 1]
(1) Preparation of amorphous silica powder Silica stone powder having an average particle diameter of 50 μm was prepared as a silica source powder, and aluminum oxide powder having an average particle diameter of 5 μm was prepared as an aluminum source powder.

(1-1) Preparation of Amorphous Silica Powder A Silica powder and aluminum oxide powder are mixed to obtain an oxide-equivalent Al amount shown in Table 1 below in a particle size range of 3 to 60 μm (particle size range A). After that, the mixed powder is sprayed onto the burner of the apparatus described in JP-A-11-57451, melted in a flame of 2000 ° C. or higher, subjected to a flame treatment for amorphization and spheroidization, and amorphous Silica powder A was produced. When the average particle diameter of the amorphous silica powder A was measured, it was 50 μm.

(1-2) Preparation of Amorphous Silica Powder B Silica stone powder and aluminum oxide powder were mixed to obtain an oxide equivalent Al amount shown in Table 1 below in a particle size range of 0.01 to 2 μm (particle size range B). After making the mixed powder, the mixed powder is sprayed onto the burner of the apparatus described in JP-A-11-57451, melted in a flame of 2000 ° C. or higher, and subjected to a flame treatment for amorphization and spheroidization, Amorphous silica powder B was produced. When the average particle diameter of the amorphous silica powder B was measured, it was 0.45 μm.

  In addition, LPG and oxygen gas were used for formation of said flame, and oxygen gas was also used for the carrier gas which conveys raw material powder to a burner.

  The obtained amorphous silica powder A and amorphous silica powder B were mixed at a mass ratio of 95: 5 to obtain amorphous silica powder. The average particle size of the amorphous silica powder was measured and found to be 47.5 μm. Moreover, the total of the specific surface area, the oxide conversion Al amount, the oxide conversion Si amount, the average circularity, and the contents of U and Th was measured. The results are shown in Table 1 below.

(2) Production of Resin Composition and Semiconductor Encapsulant 89 parts by mass of the produced amorphous silica powder, 5.5 parts by mass of a biphenyl type epoxy resin (YX-4000HK manufactured by Japan Epoxy Resin Co., Ltd.), and a phenol resin (MEHC-7800S manufactured by Meiwa Kasei Co., Ltd.) 4.8 parts by mass, 0.15 parts by mass of triphenylphosphine (manufactured by Hokuko Chemical Co., Ltd .: TPP), and epoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-403) 35 parts by mass of the mixture was dry blended with a Henschel mixer, and the same direction meshing twin screw extruder kneader (screw diameter D = 25 mm, L / D = 10.2, paddle rotation speed 50 to 120 rpm, discharge amount 3.0 kg / (Hr, kneaded material temperature 98-100 ° C.) and kneaded to obtain a resin composition. The resin composition (discharged material) was pressed with a press machine, cooled, and then pulverized to produce a semiconductor encapsulant. About the produced resin composition and semiconductor sealing material, the fixation rate, spiral flow (fluidity), gel time, and cohesiveness were evaluated as follows. The results are shown in Table 1 below.

[Examples 2 to 6]
An amorphous silica powder was produced in the same manner as in Example 1 except that the average particle diameters of the amorphous silica powders A and B and the oxide-converted Al amount were changed as shown in Table 1 below. The results of measuring the physical properties of each powder are shown in Table 1 below.

  Using the produced amorphous silica powder, a resin composition and a semiconductor encapsulating material were produced in the same manner as in Example 1. About the produced resin composition and the semiconductor encapsulating material, the adhesion rate, spiral flow (fluidity) , Gel time, and aggregation were evaluated. The results are shown in Table 1 below.

[Comparative Examples 1-5]
An amorphous silica powder was produced in the same manner as in Example 1 except that the average particle diameters of the amorphous silica powders A and B and the amount of Al in terms of oxide were changed as shown in Table 2 below. The results of measuring the physical properties of each powder are shown in Table 2 below.

  Using the produced amorphous silica powder, a resin composition and a semiconductor encapsulating material were produced in the same manner as in Example 1. About the produced resin composition and the semiconductor encapsulating material, the adhesion rate, spiral flow (fluidity) , Gel time, and aggregation were evaluated. The results are shown in Table 2 below.

(Fixing rate)
Amorphous silica powder was treated with 1% by mass of KBM-403 and allowed to stand at room temperature and normal humidity for 1 week. 3 g of sample A was weighed into a centrifuge tube and mixed with 40 g of acetone. This mixed slurry was separated with a centrifuge at 350 rpm for 10 minutes, and the supernatant was discarded. Sample B was obtained by drying the obtained sediment after performing the above mixing / separation operation twice. Samples A and B were measured for total organic carbon (TOC). The value calculated from the following calculation formula was defined as the sticking rate.
Adhesion rate (%) = (TOC value of sample A) / (TOC value of sample B) × 100
The fixing rate is effective for qualitative evaluation mainly on the ratio of the free silane coupling agent, and is preferably 40 to 90. When it is within this range, there is little free silane coupling agent, and aggregation tends to hardly occur.

(Spiral flow)
The spiral flow value of each semiconductor encapsulant was measured using a transfer molding machine equipped with a spiral flow measurement mold in accordance with EMMI-I-66 (Epoxy Molding Material Institute; Society of Plastic Industry).
The transfer molding conditions were a mold temperature of 175 ° C., a molding pressure of 7.4 MPa, and a pressure holding time of 120 seconds. It shows that fluidity | liquidity is so favorable that this value is large (preferably 60 cm or more).

(Geltime)
The gel time is one index representing the time until the resin composition is melt-cured. When the gel time is long, it is difficult to control the curability in the production process. The gel time was measured by measuring the time until the resin composition was melted and cured on a metal block heated to 175 ° C.
The gel time is preferably 15 to 21 seconds from the viewpoint of controlling the curing time during production.

(Cohesiveness)
50 g of the pulverized product obtained by pulverizing the prepared resin composition to a particle size of about 0.1 to 2 mm is allowed to stand at room temperature (about 25 ° C.) for 7 days, and then placed on a JIS sieve with a mesh opening of 2 mm and sieved for 1 minute using a low tap tester. It was. The mass remaining on the sieve was weighed, and the value obtained as mass% was defined as the amount of aggregation. The aggregation amount is preferably 1% by mass or less from the viewpoint of uniform diffusibility during compression molding.

As is apparent from Tables 1 and 2, by using the amorphous silica powder of the example, the pulverized product is less likely to aggregate with each other, and the spiral flow and gel time are good. It has been found suitable.
The amorphous ratio of the amorphous silica powders obtained in the examples and comparative examples was 95% or more.

  The amorphous silica powder of the present invention is used as a filler for semiconductor sealing materials used in automobiles, portable electronic devices, personal computers, home appliances, etc., and laminates on which semiconductors are mounted. Moreover, the resin composition of the present invention is used as a prepreg for printed circuit boards, various engineer plastics, etc. formed by impregnating and curing glass woven fabric, glass nonwoven fabric, and other organic base materials in addition to the semiconductor sealing material. it can.

Claims (5)

An amorphous silica powder having an average particle diameter of 2 to 50 μm, an Al content of 500 to 3000 ppm in terms of oxide, and an Si content of 99.0% by mass or more in terms of oxide,
The average particle size of the amorphous silica powder in the particle size range of 3 to 60 μm which is the particle size range A is 5 to 50 μm and the Al content is 500 ppm or less in terms of oxide,
Amorphous silica powder having an average particle size of 0.025 to 1.000 μm and an Al content of 10,000 to 50,000 ppm in terms of oxides in a particle size range of 0.01 to 2 μm in the particle size range B .   The amorphous silica powder according to claim 1, having an average sphericity of 0.85 or more.   The amorphous silica powder according to claim 1 or 2, wherein the total content of U and Th is 20 ppb or less.   A resin composition comprising the amorphous silica powder according to claim 1 and a resin. The semiconductor sealing material formed using the resin composition of Claim 4.