Spherical silica particles, resin composite composition containing same, and method for manufacturing same

Abstract

Provided are spherical silica particles having excellent fluidity, a resin composite composition containing the spherical silica particles, and a method for producing the same. Among particles of 1 [mu] m to 30 [mu] m detected by a Coulter counter, the number frequency of particles of 3 [mu] m or more is 300 ppm to 50000 ppm, and the number frequency of particles of 5 [mu] m or more is 100 ppm or less. Spherical silica particles having a specific surface area of 5.0 m2 / g or more and 20 m2 / g or less as measured by a BET method; a resin composite composition containing the spherical silica particles; and a method for producing the spherical silica particles.

Description

Technical Field

[0001] The present invention relates to spherical silica particles, and more particularly to spherical silica particles, wherein among particles of 1 μm or more and 30 μm or less detected by a Coulter counter, the number frequency of particles of 3 μm or more is 300 ppm or more and 50,000 ppm or less, and the number frequency of particles of 5 μm or more is 100 ppm or less, and the specific surface area measured by the BET method is 5.0 m 2 / g above 20m 2 / g or less and thus having excellent fluidity, a resin composite composition containing the spherical silica particles, and a method for producing the spherical silica particles. Background Art

[0002] The miniaturization and thinning of semiconductor packages such as ICs and CPUs are constantly developing, and with this, the demand for thinner diameters and narrower pitches of bonding wires is increasing. On the other hand, as the heat generation increases with the high performance of semiconductor elements, it becomes more important to improve the heat dissipation of semiconductor packages. The demand for sealing materials used in semiconductor packages also requires sealing materials with higher flowability due to improved filling properties in narrow areas, and high thermal conductivity is also required. As a sealing material for semiconductor packages, a resin composite composition in which silica particles are filled in epoxy resin as a filler is used, but due to the increased demand for high flowability in recent years, spherical particles are mostly used for silica particles used as fillers. By using the spherical silica particles, the fluidity of the sealing material can be significantly improved compared to the previous crushed silica particles.

[0003] However, as the demand for high thermal conductivity of the sealing material increases, it is necessary to increase the filling rate of fillers with higher thermal conductivity than resins, and improve the thermal conductivity of the sealing material. In addition, in the case of reducing the thermal expansion rate while improving the strength of the sealing material, it is also necessary to increase the filling rate of the filler. However, if the filling rate of the filler is increased, the fluidity will decrease, and thus attempts such as optimizing the particle size distribution are carried out. In addition, in order to improve the space filling rate of the filler particles, a method of matching particles with several particle size distributions is usually adopted.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2022-037681

[0007] Patent Document 2: Japanese Patent Application Publication No. 2007-015884

[0008] Patent Document 3: Japanese Patent Application Publication No. 2022-90679 Summary of the invention

[0009] Technical problem to be solved by the invention

[0010] As described above, the resin composite composition or the filler thereof as a sealing material has been studied from various viewpoints such as fluidity or filling property, heat dissipation (thermal conductivity), and strength.

[0011] For example, Patent Document 1 proposes a method of appropriately adjusting the particle size distribution and specific surface area of ​​the amorphous silica powder contained in the resin composite composition in order to obtain high fluidity of the resin composite composition. More specifically, the invention discloses an amorphous silica powder characterized in that the particle size frequency distribution has a maximum frequency of 1 to 10 μm, the frequency of particles smaller than 0.50 μm is 1.0% or more, and the particle size frequency distribution has a range of 1 to 12 μm. 2 / g specific surface area.

[0012] In addition, patent document 2 relates to a method for manufacturing spherical inorganic fine powders by spraying raw material powders into flames for spheroidization, and proposes a method for suppressing the coarsening of the obtained powder (particles) to form a desired particle size range. More specifically, it is disclosed that on the basis of mixing a dispersed surface treatment agent in an inorganic raw material powder of a specific average particle size, by spraying, the particle enlargement during spraying caused by the agglomeration of the raw material powder can be prevented.

[0013] Furthermore, Patent Document 3 discloses a spherical silica powder comprising the steps of forming spherical silica particles by a sol-gel method, firing the spherical silica particles, and further pulverizing the fired product.

[0014] However, the resin composite composition or its filler used as a sealing material is required to have further improved properties. In particular, with the recent miniaturization of semiconductor packages, the filler used in the sealing material is required to have a smaller particle size, but on the other hand, the reduced fluidity caused by the smaller particle size of the filler has become a problem.

[0015] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide spherical silica particles having excellent fluidity, a resin composite composition containing the spherical silica particles, and a method for producing the same.

[0016] Technical means for solving technical problems

[0017] The inventors of the present invention have found that the above-mentioned technical problems can be solved by precisely separating coarse particles in the particle size distribution of spherical silica particles, more specifically, by limiting the number of coarse particles having a particle size of or larger than a specific particle size.

[0018] Based on the above understanding, the purpose of the present invention is as follows.

[0019] [1] A spherical silica particle, characterized in that:

[0020] Among the particles with a size of 1 μm or more and 30 μm or less detected by the Coulter counter, the number frequency of particles with a size of 3 μm or more is 300 ppm or more and 50,000 ppm or less, and the number frequency of particles with a size of 5 μm or more is 100 ppm or less. The specific surface area measured by the BET method is 5.0 m 2 / g above 20m 2 / g or less.

[0021] [2] The spherical silica particles according to [1],

[0022] The D50 obtained by the laser diffraction scattering method is 0.4 or more and 3.0 or less.

[0023] [3] The spherical silica particles according to [1] or [2],

[0024] The roundness is 0.85 or more.

[0025] [4] The spherical silica particles according to any one of [1] to [3],

[0026] Among the number of particles of 1 μm to 30 μm detected by the Coulter counter, when the frequency of particles of 1 to 2 μm is A and the frequency of particles of 2 to 30 μm is B, B / A is 0.002 to 0.20.

[0027] [5] The spherical silica particles according to any one of [1] to [4],

[0028] Among the particles with a size of 1 μm or more and 30 μm or less detected by the Coulter counter, the number of particles with a size of 10 μm or more was less than 10 ppm.

[0029] [6] A resin composite composition, characterized in that:

[0030] Contains the spherical silica particles according to any one of [1] to [5].

[0031] [7] The resin composite composition according to [6],

[0032] It also contains at least one inorganic filler selected from amorphous spherical alumina particles, crystalline spherical silica particles, alumina particles, titanium dioxide particles, magnesium oxide particles, aluminum nitride particles, boron nitride particles, barium titanate particles, calcium titanate particles, and carbon fibers.

[0033] [8] A method for producing spherical silica particles according to any one of [1] to [5], wherein the spherical silica particles have a number frequency of 3 μm or more among particles of 1 μm or more and 30 μm or less detected by a Coulter counter of 300 ppm or more and 50,000 ppm or less, and a number frequency of 5 μm or more and 100 ppm or less, and a specific surface area measured by a BET method of 5.0 m 2 / g above 20m 2 / g or less, the production method is characterized in that

[0034] The method comprises the steps of melting natural silica in flame and then spheroidizing the natural silica by cooling the natural silica; and classifying the natural silica by using a classifier and / or a sieve after the spheroidizing step.

[0035] Effects of the Invention

[0036] In the spherical silica particles of the present invention and the resin composite composition containing the spherical silica particles, the particle size distribution of the spherical silica particles, especially the number frequency of particles larger than 3 μm and the number frequency of particles larger than 5 μm, is controlled in a specific area. Therefore, the fluidity is excellent, that is, the narrow part filling property is also excellent. As a result, the defective rate in semiconductor products, especially wafer-level packaging (WLP), and the recent small or thin semiconductor products can be reduced. In addition, according to the method for producing spherical silica particles of the present invention, the spherical silica particles can be obtained. DETAILED DESCRIPTION

[0037] The spherical silica particles of the present invention are characterized in that

[0038] Among the particles with a size of 1 μm or more and 30 μm or less detected by the Coulter counter, the number frequency of particles with a size of 3 μm or more is 300 ppm or more and 50,000 ppm or less, and the number frequency of particles with a size of 5 μm or more is 100 ppm or less. The specific surface area measured by the BET method is 5.0 m 2 / g above 20m 2 / g or less.

[0039] The Coulter counter measures particles using a resistance method called the Coulter principle, which eliminates errors in the surface morphology, internal structure, refractive index, color, etc. of particles seen in optical measurement methods, and achieves high measurement accuracy. In particular, the particle size obtained by this method can be expressed as a number distribution, enabling precise particle size distribution management.

[0040] Put spherical silica particles and 150 mL of electrolyte in a 200 mL glass beaker, and use an ultrasonic homogenizer (manufactured by SMT, ULTRA SONIC HOMO GENIZER UH-300) to disperse it for 30 seconds. Further, add the dispersion to the electrolyte prepared in another beaker to adjust the concentration. The dispersion after concentration adjustment is passed through a Coulter counter (manufactured by Beckman Coulter, Multisizer3), using a lens diameter of 50 μm, to measure the particle size of each spherical silica particle. At this time, the number of measured particles for each measurement is set to about 100,000, and the measurement is repeated three times for the same sample. Among the particles with a particle size of 1 μm or more and 30 μm or less detected by the Coulter counter, calculate the number of particles with a particle size of 3 and 5 μm or more as the frequency (ppm) of each coarse particle relative to the total number of measurements.

[0041] Through the measurement based on the Coulter counter, among the spherical silica particles, relative to the total measured number of particles of 1 μm to 30 μm, the number frequency of particles of 3 μm or more is 300 ppm to 50,000 ppm, and the number frequency (ratio) of coarse particles of 5 μm or more is 100 ppm or less. The so-called less than 100 ppm means, for example, when there are 100,000 particles of 1 μm to 30 μm, there are less than 10 particles of 5 μm or more. The inventors of the present invention have found that when the number frequency of coarse particles of 5 μm or more exceeds 100 ppm, such coarse particles will clog in the narrow part of the mounting substrate and the chip, and the fluidity will be reduced. As a result, the defect rate in the semiconductor product filled with the particles can be reduced.

[0042] The fewer the number frequency of coarse particles above 5 μm, the higher the fluidity, and thus it is preferred. Therefore, the number frequency can be below 90 ppm, below 80 ppm, below 70 ppm, below 60 ppm, or below 50 ppm. The number frequency of coarse particles above 5 μm can also be 0 ppm, but when the coarse particles are completely removed, that is, set to 0 ppm, there is a difficulty in increasing the burden of manufacturing management, so it can be set to a few ppm, specifically, it can be set to more than 1 ppm, or it can be set to more than 5 ppm. The lower limit of the number frequency can be adjusted according to the actual use or the allowable range of the target yield, for example, it can be set to more than 10 ppm, more than 20 ppm, or more than 30 ppm.

[0043] On the other hand, in order to properly ensure the fluidity of the resin composite composition, it is necessary to control the number frequency of coarse particles larger than 3 μm. When the number frequency is less than 300 ppm, the number of particles with a large specific surface area smaller than 3 μm increases, the viscosity increases, and the fluidity decreases. On the other hand, when the number frequency is higher than 50,000 ppm, it is difficult to prevent particles larger than 5 μm from mixing in, and clogging occurs in the narrow part of the mounting substrate and the chip, and the fluidity decreases. The preferred upper limit of the number frequency is 30,000 ppm, and 20,000 ppm is more preferred. In addition, the preferred lower limit of the number frequency is 500 ppm, 1000 ppm is more preferred, and 2000 ppm is more preferred.

[0044] In addition, among the particles of 1 μm or more and 30 μm or less detected by the Coulter counter, the number frequency of particles of 10 μm or more is preferably less than 10 ppm. The fewer the number frequency of coarse particles of 10 μm or more, the higher the fluidity, so it is preferred. When the number frequency of coarse particles of 10 μm or more is more than 10 ppm, such coarse particles clog the narrow part of the mounting substrate and the chip, and the fluidity is reduced. It is more preferably less than 5 ppm, more preferably less than 1 ppm, further preferably less than 0.1 ppm, and most preferably zero.

[0045] In addition, among the number of particles above 1 μm and below 30 μm detected by the Coulter counter, when the frequency of the number of particles of 1 to 2 μm is set to A and the frequency of the number of particles of 2 to 30 μm is set to B, B / A is preferably above 0.002 and below 0.20. Although this indicates that it is preferred to contain 1 to 2 μm particles in excess relative to 2 to 30 μm particles, if there are too many 1 to 2 μm particles with a large surface area, the fluidity deteriorates. By setting this range, the fluidity of the resin composite composition is appropriately ensured, and the filling (combination) effect of the filler is fully demonstrated. The preferred lower limit of B / A is 0.01, more preferably 0.03, more preferably 0.05, and further preferably 0.10. On the other hand, the preferred upper limit of B / A is 0.19.

[0046] In order to obtain the desired particle size distribution, classification can also be performed. For classification, a conventionally known method can be used, which can be either wet classification or dry classification. In addition, it can also be any of gravity field classification, inertial force field classification, and centrifugal force field classification. In the case of centrifugal field classification, it can be a free vortex type or a forced vortex type. Preferably, for example, a method of using a precision wind classifier (also called an "air classifier") to separate the coarse powder side and the fine powder side can be exemplified. Among them, in the present invention, in the classification management, by measuring the number frequency based on the Coulter counter, the precise management of the particle size distribution is performed, which can contribute to the excellent properties of the spherical silica particles, such as fluidity.

[0047] The spherical silica particles of the present invention exhibit the effects of the invention independently of the crystallinity. Among them, since amorphous silica has a lower thermal expansion coefficient than crystalline silica, in order to further effectively reduce the thermal expansion coefficient of the resin composition, the crystallinity is preferably 20% or less. More preferably, it is 10% or less, and even more preferably, it is 5% or less. It is further preferably 1% or less. It is further preferably 0.1% or less.

[0048] Here, the so-called "crystallinity" refers to the ratio of amorphous and crystalline silica in spherical silica particles. The crystallinity can be obtained by XRD. In the measurement by XRD, the ratio of the crystalline phase can be calculated according to the following formula based on the sum of the integrated intensity of the crystalline peak (Ic) and the integrated intensity of the amorphous halo part (Ia):

[0049] X (crystal phase ratio) = Ic / (Ic+Ia)×100(%).

[0050] In the present invention, real-time XRD measurement was performed in the range of 2θ = 10° to 90°. The crystal phase ratio was determined from the sum of the crystalline peak intensities in the 2θ measurement range and the integrated intensity of the broad amorphous halo portion appearing around 2θ = 22°.

[0051] In the present invention, an X-ray diffraction apparatus "D2 PHASER" (manufactured by Bruker) was used.

[0052] The spherical silica particles of the present invention can be made by methods such as spraying. In the spraying method, natural silica powder that is crushed and adjusted to a desired particle size is passed through a flame, so that the particles melt and the shape of the particles becomes spherical due to surface tension. By such a spraying method, spherical silica particles with a roundness of more than 0.80, preferably more than 0.85, can be made. In addition, it can also be obtained by burning metals. For example, a metal powder mixture of silicon powder, silicone powder, etc. can be formed into a chemical flame together with a carrier gas in an atmosphere containing oxygen, and microparticles of the target silicon dioxide "SiO2" are obtained in the chemical flame. In addition, the above-mentioned crystallinity can be controlled by the heat treatment (melting, cooling, etc. of the particles) conditions in the manufacturing process of the spherical silica particles.

[0053] In addition, the spherical silica particles can be mixed with other inorganic fillers within the range of obtaining the desired shape. Here, the so-called other inorganic fillers include fillers with different particle size distributions in addition to fillers of different types such as aluminum oxide powder, magnesium oxide powder, and titanium dioxide powder. The types of other inorganic fillers will be described later.

[0054] In one embodiment of the present invention, the spherical silica particles may have a D50 of 0.4 to 3.0 μm as measured by a laser diffraction scattering method.

[0055] The particle size distribution of spherical silica particles can also be measured by laser diffraction scattering method. As a particle size distribution measuring machine, for example, "Mastersizer 3000" (manufactured by Malvern) can be used for measurement. In this measurement, the refractive index of water as a solvent is 1.33, and the refractive index of the powder is considered. For example, for amorphous silica, the refractive index is set to 1.54 for measurement.

[0056] D50 (median particle size) is the particle size at which the cumulative volume accounts for 50% in the cumulative particle size distribution of spherical silica particles, and D100 (maximum particle size) is the particle size at which the cumulative volume accounts for 100% in the cumulative particle size distribution of spherical silica particles.

[0057] When D50 is less than 0.4, the particle size is small, and the viscosity of the sealing material containing the particles may become too high. On the other hand, when D50 is higher than 3.0 μm, there may be a problem of particle sedimentation during storage, filling, or curing, or an increase in the mixing of particles larger than 5 μm, and the particles may get stuck in the narrow part between the mounting substrate and the chip, which may cause the fluidity of the sealing material to deteriorate and the moldability to decrease. The more preferred lower limit is 1.0 μm. On the other hand, the more preferred upper limit is 2.0 μm.

[0058] The spherical silica particles of the present invention have a specific surface area of ​​5 m 2 / g above 20m 2 / g or less.

[0059] The specific surface area of ​​the spherical silica particles can be measured by the BET method. The specific surface area is measured using a specific surface area measuring device "Macsorb Model HM-1208" manufactured by Mountech Corporation.

[0060] The specific surface area of ​​spherical silica particles is less than 5m 2 / g, since it is difficult for the particles to form the densest filling structure, the fluidity of the sealing material containing the particles may sometimes decrease. Preferably, the specific surface area can be 6m 2 / g or more, can also be 7m 2 On the other hand, the specific surface area of ​​spherical silica particles is higher than 20 m 2 / g, the tendency of particles to aggregate increases, and the fluidity of the sealing material sometimes decreases. Preferably, the specific surface area can be 15m 2 / g or less, can also be 12m 2 / g or less.

[0061] In one embodiment of the present invention, the spherical silica particles may have a roundness of 0.85 or more.

[0062] The higher the roundness of the spherical silica particles, the lower the viscosity of the resin composite composition containing the particles, and the better the moldability. The roundness can be 0.90 or more, or 0.93 or more. The upper limit of the roundness is theoretically 1.0, but from the perspective of manufacturing management, it can also be 0.98 or less, or 0.95 or less.

[0063] The roundness can be measured using an electron microscope or an optical microscope and an image analysis device. For example, FPIA manufactured by SYSMEX Co., Ltd. Use these devices to measure the roundness of the particles (the circumference of the equivalent circle / the circumference of the particle projection image). The roundness is measured for more than 100 particles, and the average value is used as the roundness of the powder.

[0064] In one embodiment of the present invention, a resin composite composition containing spherical silica particles is provided, and a resin composite body obtained by curing the resin composite composition can be produced. The components of the resin composite composition are described below.

[0065] The slurry composition containing spherical silica particles and resin can be used to obtain a resin composite composition such as a semiconductor sealing material (especially a solid sealing material) and an interlayer insulating film. In addition, by curing these resin composite compositions, a resin composite such as a sealing material (cured body) and a semiconductor packaging substrate can be obtained.

[0066] When manufacturing the resin composite composition, for example, in addition to the spherical silica particles and the resin, a curing agent, a curing accelerator, a flame retardant, a silane coupling agent, etc. may be added as needed, and the composite may be formed by a known method such as kneading. Furthermore, the composite composition may be formed into a pellet or a film according to the intended use.

[0067] In addition, when manufacturing the resin composite composition, in addition to the spherical silica particles and the resin, other inorganic fillers may be added. Examples of the inorganic fillers include amorphous spherical silica particles, amorphous spherical alumina particles, crystalline spherical silica particles, alumina particles, titanium dioxide particles, magnesium oxide particles, aluminum nitride particles, boron nitride particles, barium titanate particles, calcium titanate particles, and carbon fibers. The mixing ratio of the inorganic filler can be appropriately adjusted according to the use of the resin composite composition, but from the perspective of exerting the effect of the spherical silica particles of the present invention, it is preferred that (mixing weight of spherical silica particles): (mixing weight of other inorganic fillers) = 95:5 to 60:40.

[0068] Furthermore, when the resin composite composition is cured to produce a resin composite, for example, the resin composite composition may be heated and melted, processed into a shape corresponding to the application, and then completely cured by applying a higher heat than when it was melted. In this case, a known method such as transfer molding or compression molding may be used.

[0069] For example, in the case of manufacturing semiconductor-related materials such as a substrate for packaging or an interlayer insulating film, the resin used as the resin composite composition can be a known resin, but preferably an epoxy resin. The epoxy resin is not particularly limited, but for example, bisphenol A epoxy resin, bisphenol F epoxy resin, biphenyl epoxy resin, phenol novolac epoxy resin, cresol novolac epoxy resin, naphthalene epoxy resin, phenoxy epoxy resin, etc. can be used. One of them can be used alone, or two or more with different molecular weights can be used in combination. Among them, from the viewpoints of curability, heat resistance, etc., an epoxy resin having two or more epoxy groups in one molecule is preferred. Specifically, biphenyl epoxy resins, phenol novolac epoxy resins, o-cresol novolac epoxy resins, epoxidized products of phenolic and aldehyde thermoplastic novolac resins, glycidyl ethers such as bisphenol A, bisphenol F, and bisphenol S, glycidyl ester acid epoxy resins obtained by reaction of polyacids such as phthalic acid or dimer acid with epichlorohydrin, linear aliphatic epoxy resins, alicyclic epoxy resins, heterocyclic epoxy resins, alkyl-modified multifunctional epoxy resins, β-naphthol novolac epoxy resins, 1,6-dihydroxynaphthalene epoxy resins, 2,7-dihydroxynaphthalene epoxy resins, bishydroxybiphenyl epoxy resins, and epoxy resins into which halogens such as bromine are introduced for flame retardancy, etc. Among these epoxy resins having two or more epoxy groups in one molecule, bisphenol A epoxy resins are particularly preferred.

[0070] In addition, resins other than epoxy resins can also be used as resins used in resin composite compositions such as polyester films for printed circuit boards and various engineering plastics for uses other than composite materials for semiconductor sealing materials. Specifically, in addition to epoxy resins, there are polyamides such as silicone resins, phenolic resins, melamine resins, urea resins, unsaturated polyesters, fluororesins, polyimides, polyamide-imides, and polyetherimides; polyesters such as polybutylene terephthalate and polyethylene terephthalate; polyphenylene sulfide, aromatic polyester, polysulfone, liquid crystal polymer, polyether sulfone, polycarbonate, maleimide-modified resins, ABS resins, AAS (acrylonitrile butyl acrylate·styrene) resins, and AES (acrylonitrile·butadiene·propylene·diene rubber-styrene) resins.

[0071] As the curing agent used in the resin composite composition, any known curing agent may be used to cure the resin, and for example, a phenolic curing agent may be used. As the phenolic curing agent, phenolic novolac resins, alkylphenol novolac resins, polyvinylphenols, etc. may be used alone or in combination of two or more.

[0072] The phenol curing agent is preferably blended in an equivalent ratio (phenolic hydroxyl equivalent / epoxy equivalent) of 0.1 or more and less than 1.0 to the epoxy resin. This prevents unreacted phenol curing agent from remaining and improves moisture absorption and heat resistance.

[0073] From the viewpoint of heat resistance and thermal expansion coefficient, the amount of spherical silica particles added to the resin composite composition is preferably large, but it is usually 70% to 95% by mass, preferably 80% to 95% by mass, and more preferably 85% to 95% by mass. This is because when the amount of spherical silica particles is too small, it is difficult to obtain the effects of improving the strength of the sealing material or inhibiting thermal expansion, and on the contrary, if it is too much, regardless of the surface treatment of the spherical silica particles, it is easy to cause segregation caused by the agglomeration of spherical silica particles in the composite material, and the viscosity of the composite material becomes too large, so it is difficult to use as a sealing material. In addition, when used simultaneously with the aforementioned "other fillers", the preferred amount added in the resin composite composition is the sum of the spherical alumina particles and the "other fillers".

[0074] Moreover, as for the silane coupling agent, a known coupling agent may be used, but it is preferable that the silane coupling agent has an epoxy functional group.

[0075] As an example of the fluidity (narrowed portion fluidity) of the resin composite composition containing spherical silica particles, it is measured in the following procedure.

[0076] The length of each resin composite composition containing spherical silica particles flowing into the slit was measured using a transfer molding machine equipped with a measuring mold having a slit with a groove depth of 10 μm or less. In addition, the transfer molding conditions were set to a mold temperature of 175°C, a molding pressure of 7 MPa, and a holding time of 180 seconds. The larger the length, the better the fluidity.

[0077] In addition, regarding the resin composite composition for fluidity measurement, spherical silica particles and a resin under prescribed conditions are prepared at a mixing ratio. As an example, a biphenyl epoxy resin (YX4000H (manufactured by Mitsubishi Chemical Co., Ltd.) and spherical silica particles are mixed at a ratio of 25:75 (wt%), and further prepared by adding a curing agent, a curing accelerator, a release agent, and an epoxy silane coupling agent.

[0078] The method for producing spherical silica particles according to one embodiment of the present invention comprises the steps of melting natural silica in a flame and then spheroidizing it by cooling; and, after the spheroidizing step, simultaneously performing classification using a classifier (e.g., a precision wind classifier) ​​and / or a sieve. According to the production method, spherical silica particles can be produced, wherein among particles of 1 μm or more and 30 μm or less detected by a Coulter counter, the number frequency of particles of 3 μm or more is 300 ppm or more and 50,000 ppm or less, and the number frequency of particles of 5 μm or more is 100 ppm or less, and the specific surface area measured by the BET method is 5.0 m 2 / g above 20m 2 / g or less.

[0079] [Example]

[0080] The present invention will be described below with reference to the following examples and comparative examples, but the present invention is not limited to the following examples.

[0081] (Examples 1 to 6, Comparative Examples 1 to 4)

[0082] Natural silica is crushed, and the crushed material is supplied to a high-temperature flame formed by the combustion of LPG and oxygen, and melted and spheroidized to obtain spherical silica particles. The flame formation conditions, raw material particle size, raw material supply amount, classification conditions, mixing conditions, etc. are adjusted to produce various powders shown in Table 1. Specifically, the adjustment of the particle size distribution is carried out by adjusting the raw material particle size and multi-stage screening and classification operations of the powder after spheroidization, and the final process is classified using a precision wind classifier. The number frequency of particles larger than 5 μm among particles larger than 1 μm and smaller than 30 μm detected by the Coulter counter, D50 (or mode diameter) based on the laser diffraction scattering method, specific surface area measured by the BET method, roundness, the ratio of the number frequency based on the Coulter counter B / A (the number frequency of particles of 1 to 2 μm is set as A, and the number frequency of particles of 2 to 30 μm is set as B), and the number frequency of particles larger than 10 μm based on the Coulter counter are adjusted by adjusting the mixing amount of the various powders obtained in the above operation. For example, the number frequency or its ratio is adjusted by mixing particles of known number frequency in an appropriate ratio, the specific surface area is adjusted by adding ultrafine powders with various particle sizes and specific surface areas, and the roundness is controlled by adjusting the flame formation conditions and the raw material supply amount.

[0083] Table 1 shows the physical property values ​​of the used spherical silica particles.

[0084] [Table 1]

[0085]

[0086] The measurement methods of various physical property values ​​are described below.

[0087] (Determination based on Coulter counting method)

[0088] Put spherical silica particles and 150 mL of electrolyte in a 200 mL glass beaker, and use an ultrasonic homogenizer (manufactured by SMT, ULTRASONIC HOMO GENIZER UH-300) to disperse it for 30 seconds. Further, add the dispersion to the electrolyte prepared in another beaker to adjust the concentration. The dispersion after concentration adjustment is passed through a Coulter counter (manufactured by Beckman Coulter, Multisizer 3) using a lens diameter of 50 μm to measure the particle size of each spherical silica particle. At this time, the number of measured particles for each measurement is set to about 100,000, and the measurement is repeated three times for the same sample. Among them, the number of particles with a particle size of 3 and 5 μm or more is calculated as the frequency (ppm) of each coarse particle relative to the total number of measurements. Similarly, the frequency A of the number of particles with a particle size of 1 to 2 μm, the frequency B of the number of particles with a particle size of 2 to 30 μm, and the frequency of the number of particles with a particle size of 10 μm or more are also measured.

[0089] (D50 obtained by laser diffraction scattering method)

[0090] As a particle size distribution measuring machine, "Mastersizer 3000" (manufactured by Malvern) was used for measurement. When measuring, the refractive index of water as a solvent was 1.33, and the refractive index of the powder was considered in consideration of the refractive index of the material of the powder. For example, for amorphous silicon dioxide, the refractive index was set to 1.54 for measurement.

[0091] (Specific surface area)

[0092] The specific surface area (BET value) was determined by applying the BET theory to the adsorption isotherm measured by the gas adsorption method (BET method). The specific surface area was measured using a specific surface area measuring instrument "Macsorb Model HM-1208" manufactured by Mountech Corporation.

[0093] (Roundness)

[0094] The determination of roundness can be carried out using an electron microscope or an optical microscope and an image analysis device. For example, FPIA manufactured by SYSMEX, etc. Use these devices to measure the roundness of the particles (the circumference of the equivalent circle / the circumference of the projection image of the particle). The roundness is measured for more than 100 particles, and the average value is used as the roundness of the powder.

[0095] (Flowability (Narrow Section Flowability))

[0096] A transfer molding machine equipped with a measuring mold having a slit with a groove depth of less than 10 μm was used to measure the length of each resin composite composition containing spherical silica particles flowing toward the slit. In addition, the transfer molding conditions were set to a mold temperature of 175°C, a molding pressure of 7 MPa, and a holding time of 180 seconds. The longer the length, the better the fluidity. When the length is large (more than 2.5 cm), it is recorded as ○ (excellent), when it is more than 1.5 cm and less than 2.5 cm, it is recorded as △ (good), and when it is small (less than 1.5 cm), it is recorded as × (bad).

[0097] The resin composite composition used for the fluidity measurement was prepared by mixing a biphenyl epoxy resin (YX4000H (manufactured by Mitsubishi Chemical Corporation) and spherical silica particles at a ratio of 25:75 (wt%), and further adding a curing agent, a curing accelerator, a release agent, and an epoxy silane coupling agent.

[0098] (True specific gravity)

[0099] The true specific gravity of the silica particles was measured by a pycnometer method (liquid phase replacement method) using a continuous automatic powder true density measuring device (manufactured by Seishin Enterprise Co., Ltd., trade name: AUTO TRUEDENSER MAT-7000).

[0100] Resin composite compositions containing the silica particles of Examples 1 to 6 and Comparative Examples 1 to 4 were prepared, and the above-mentioned fluidity (narrow portion fluidity) was measured. The measurement results are shown in Table 1. For the spherical silica particles within the scope of the present invention, good fluidity of ○ (excellent) or △ (good) was confirmed.

[0101] Industrial Applicability

[0102] The spherical silica particles of the present invention and the resin composite composition containing the spherical silica particles show good fluidity and are not limited to materials in semiconductor sealing, but can also be used in other applications. Specifically, they can also be used as polyester films for printed circuit boards, or various engineering plastics. In addition, according to the method for producing spherical silica particles of the present invention, the spherical silica particles can be obtained.

Claims

1. A spherical silica particle, characterized in that: Among the particles with a size of 1 μm or more and 30 μm or less detected by the Coulter counter, the number frequency of particles with a size of 3 μm or more is 300 ppm or more and 50,000 ppm or less, and the number frequency of particles with a size of 5 μm or more is 100 ppm or less. The specific surface area measured by the BET method is 5.0 m 2 / g above 20m 2 / g or less.

2. The spherical silica particles according to claim 1, D50 obtained by a laser diffraction scattering method is 0.4 to 3.0 μm.

3. The spherical silica particles according to claim 1, The roundness is 0.85 or more.

4. The spherical silica particles according to claim 1, Among the number of particles of 1 μm to 30 μm detected by the Coulter counter, when the frequency of particles of 1 to 2 μm is A and the frequency of particles of 2 to 30 μm is B, B / A is 0.002 to 0.

20.

5. The spherical silica particles according to claim 1, Among the particles of 1 μm or more and 30 μm or less detected by the Coulter counter, the particles of 10 μm or more accounted for less than 10 ppm.

6. A resin composite composition, characterized in that: Containing the spherical silica particles according to any one of claims 1 to 5.

7. The resin composite composition according to claim 6, It also contains at least one inorganic filler selected from amorphous spherical alumina particles, crystalline spherical silica particles, alumina particles, titanium dioxide particles, magnesium oxide particles, aluminum nitride particles, boron nitride particles, barium titanate particles, calcium titanate particles, and carbon fibers.

8. A method for producing spherical silica particles, wherein among particles of 1 μm or more and 30 μm or less detected by a Coulter counter, the number frequency of particles of 3 μm or more is 300 ppm or more and 50,000 ppm or less, and the number frequency of particles of 5 μm or more is 100 ppm or less, and the specific surface area measured by the BET method is 5.0 m 2 / g above 20m 2 / g or less, the production method is characterized in that The method comprises: a step of melting natural silica in flame and then spheroidizing it by cooling; and a step of classifying it by using a classifier and / or a sieve simultaneously after the spheroidizing step.

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