Surface-treated inorganic particles, resin composite composition containing same, and method for producing same

Abstract

The purpose of the present invention is to provide a novel surface-treated inorganic particle which are obtained by a surface treatment that is different from conventional surface treatments using a silane coupling agent or a silane agent.　A surface-treated inorganic particle according to the present disclosure is characterized in that: per specific surface area, the peak intensity ratio al / c of the peak intensity al of a peak attributed to Al2p to the peak intensity c of a peak attributed to C1s is 0.010-0.500, the peak intensity ratio si / c of the peak intensity si of a peak attributed to Si2p to the peak intensity c of the peak attributed to C1s is 0.010-0.300, or the peak intensity ratio n / c of the peak intensity n of a peak attributed to N1s to the peak intensity c of the peak attributed to C1s is 0.010-0.250 as measured by X-ray photoelectron spectroscopy (XPS); the average particle diameter is 0.1-180.0 µm; and the specific surface area is 0.10-5.00 m2 / g.

Description

Surface-treated inorganic particles, resin composite composition containing the same, and method for producing the same

[0001] The present invention relates to surface-treated inorganic particles, a resin composite composition containing the same, and a method for producing the surface-treated inorganic particles.

[0002] In semiconductor devices and electronic components that consist of IC chips, encapsulants are used to protect and insulate the IC chips. There are various types of encapsulants, including solid and liquid encapsulants. Solid encapsulants are used in the transfer molding method, where the encapsulant is melted, poured into a mold, shaped, and then cooled and solidified. Liquid encapsulants are mainly used in the compression method, where the IC chip is immersed in a fluid resin and then the fluid resin is hardened.

[0003] In recent years, as semiconductor devices and electronic components have become more powerful, more functional, and smaller and lighter, the IC chips they incorporate have also become more highly integrated, smaller, and thinner. The gaps between stacked IC chips are extremely narrow, making sealing difficult with conventional solid encapsulants, so liquid encapsulants are used.

[0004] Sealing materials are made by blending inorganic particles that serve as fillers with a resin that serves as a matrix. Silica, alumina, etc. are often used as these inorganic particles. The surfaces of inorganic particles such as silica and alumina fillers have OH groups and are hydrophilic. On the other hand, the matrix resins, such as epoxy resins and silicone resins, are hydrophobic, so the adhesion between the inorganic particles and the resin is poor. For this reason, the adhesion between the resin and the filler is one of the important management items for sealing materials.

[0005] Patent Document 1 is a document relating to a silica particle dispersion (a dispersion of silica particles in a solvent for obtaining a sealant) and surface-treated silica particles. Specifically, it proposes that the surface of the silica particles is treated with a phenylalkoxysilane to increase the hydrophobicity and stabilize the dispersion state of the surface-treated silica particles in a dispersion medium for a long period of time.

[0006] Patent Document 2 is a document relating to an alumina powder and a resin composition containing the same. Specifically, it proposes that the affinity between the alumina powder and the resin is increased by surface-treating the alumina powder with a silane compound.

[0007] Patent No. 6805538 Patent No. 6585594

[0008] As shown in Patent Documents 1 and 2, conventional techniques involve using a silane coupling agent or a silane agent to improve the compatibility or adhesion between a filler and a resin.

[0009] However, when applying such silane coupling agents or silane agents to fillers, they require the preparation of a hydrolysis solution. The tendency for hydrolysis to occur is due to the structure of the agent, and the hydrolysis process can be very slow and take a long time. Furthermore, the agents after hydrolysis are unstable, and before bonding with the filler to be surface treated, they may polymerize with each other, preventing the desired surface treatment.

[0010] An object of the present invention is to provide novel surface-treated inorganic particles that are different from conventional surface treatments using silane coupling agents or silane agents.

[0011] The present inventors have discovered that by subjecting inorganic particles to a specific surface treatment, generally speaking, surface treatment so that the carbon to aluminum peak ratio falls within a predetermined range, it is possible to provide novel surface-treated inorganic particles that differ from conventional surface treatments using silane coupling agents or silane agents.

[0012] Based on the above findings, the gist of the present invention is as follows.

[0013] [1] As measured by X-ray photoelectron spectroscopy (XPS), the peak intensity ratio al / c of ​​the peak intensity c of the peak attributed to C1s to the peak intensity al of the peak attributed to Al2p is 0.010 to 0.500, the peak intensity ratio si / c of ​​the peak intensity c of the peak attributed to C1s to the peak intensity si of the peak attributed to Si2p is 0.010 to 0.300, or the peak intensity ratio n / c of ​​the peak intensity c of the peak attributed to C1s to the peak intensity n of the peak attributed to N1s is 0.010 to 0.250, the average particle size is 0.1 to 180.0 μm, and the specific surface area is 0.10 to 5.00 m ２ / g.

[0014] [2] The surface-treated inorganic particles according to [1], having a circularity of 0.85 or more.

[0015] [3] The surface-treated inorganic particles according to [1] or [2], which have a degree of aggregation of 1.0% or less.

[0016] [4] The surface-treated inorganic particles according to any one of [1] to [3], which have a weight loss rate of 5.0% or less when heated from room temperature to 200°C as measured by a gravimetric method.

[0017] [5] The surface-treated inorganic particles according to any one of [1] to [4], which are at least one selected from amorphous silica, crystalline silica, alumina, titanium oxide, aluminum nitride, aluminum oxynitride, barium titanate, and magnesium oxide.

[0018] [6] 3000 to 2800 cm by Fourier transform infrared spectrophotometer (FT-IR) measurement －１ and 1665-1570 cm －１ [6] The surface-treated inorganic particles according to any one of [1] to [5], wherein an absorption spectrum is detected at

[0019] [7] A resin composite composition containing the surface-treated inorganic particles according to any one of [1] to [6].

[0020] [8] A method for producing surface-treated inorganic particles according to any one of [1] to [6], comprising: a surface treatment step of contacting surfaces of inorganic particles with a diluent solution in which a graft polymer having an anionic functional group is dissolved in a diluent; and a drying step of drying the inorganic particles that have been contacted with the diluent solution.

[0021] According to the present invention, novel surface-treated oxide particles are provided that do not require conventional surface treatment with a silane coupling agent or silane agent, thereby eliminating the inconveniences associated with surface treatment with a silane coupling agent or silane agent.

[0022] Typically, when using a silane coupling agent or a silane agent, it is necessary to adjust the hydrolysis solution, but this is not necessary in the present invention.

[0023] The susceptibility to hydrolysis is due to the structure of the drug, and although the hydrolysis may proceed very slowly and take a long time, the present invention enables surface treatment in a short time.

[0024] Furthermore, the hydrolyzed chemicals are unstable and may polymerize with each other before bonding with the filler to be surface-treated, making it impossible to achieve the desired surface treatment. However, the present invention makes it possible to achieve the intended surface treatment.

[0025] Furthermore, the composite resin composition containing the surface-treated oxide particles of the present invention can increase the flowability or reduce the thixotropy, and is therefore suitable for use as a liquid encapsulant.

[0026] Low thixotropy means that the viscosity does not change significantly whether the shear rate is high or low. Low thixotropy means that the viscosity does not change even at low shear rates, and the material flows without the application of pressure. Generally, liquid encapsulants cannot be subjected to pressure, as in transfer molding. Furthermore, adding conventional fillers to resins increases the thixotropy, making it impractical to use the composite resin composition as a liquid encapsulant. When the composite resin composition containing the surface-treated oxide particles of the present invention is used as a liquid encapsulant, the composite resin composition exhibits low thixotropy and can fill narrow gaps by itself.

[0027] [Surface-treated inorganic particles] One embodiment of the surface-treated inorganic particles of the present invention has, per specific surface area, as measured by X-ray photoelectron spectroscopy (XPS), a peak intensity ratio al / c of ​​a peak intensity c of a peak assigned to C1s to a peak intensity al of a peak assigned to Al2p of 0.010 to 0.500, a peak intensity ratio si / c of ​​a peak intensity c of a peak assigned to C1s to a peak intensity si of a peak assigned to Si2p of 0.010 to 0.300, or a peak intensity ratio n / c of ​​a peak intensity c of a peak assigned to C1s to a peak intensity n of a peak assigned to N1s of 0.010 to 0.250, an average particle size of 0.1 to 180.0 μm, and the specific surface area of ​​0.10 to 5.00 m. ２ / g.

[0028] X-ray photoelectron spectroscopy (XPS) is an analytical method that obtains elemental information and information on the chemical bonding state of a sample surface (a region several nanometers deep from the surface) by irradiating a powder sample with X-rays and then dispersing the kinetic energy of photoelectrons excited by the photoelectric effect. XPS produces a chemical shift (peak shift) depending on the chemical state of the target (powder sample). For example, the 2p orbital spectrum of aluminum (single element) has a peak in a specific energy range, whereas an oxide of aluminum exhibits a peak in a different energy range. This makes it possible to identify the state of aluminum. The atomic composition ratio can be quantified from the area intensity ratio of each spectrum. In the investigations leading to the present invention, attention was focused on five types of spectra: C1s (carbon 1s orbital spectrum), N1s (nitrogen 1s orbital spectrum), O1s (oxygen 1s orbital spectrum), Al2p (aluminum 2p orbital spectrum), and Si2p (silicon 2p orbital spectrum). In the present invention, a wide spectrum from 0 to 1100 eV was measured using a "PHI5000 VersaProbe II" (manufactured by ULVAC-PHI, Inc.). Note that, since the number of particles hit by the XPS X-ray beam can affect the appearance of peaks measured by XPS, it was decided to use peak intensity per specific surface area.

[0029] According to this embodiment, the surface state of the surface-treated inorganic particles is such that, in the spectrum obtained by wide spectrum measurement using X-ray photoelectron spectroscopy (XPS), the peak intensity ratio "al / c" between the peak intensity "c" of the peak attributable to C1s and the peak intensity "al" of the peak attributable to Al2p per specific surface area is 0.010 or more and 0.500 or less. When the peak intensity ratio "al / c" is 0.010 or more and 0.500 or less, the balance between the hydrophilicity and hydrophobicity of the surface of the inorganic particles is in a suitable range, and the mutual adhesion when the particles are mixed with a resin can be made suitable. When the peak intensity ratio "al / c" is more than 0.500, the surface treatment is insufficient, and the hydrophilicity of the surface of the inorganic particles may not be improved (maintained). In other words, the adhesion between the particles and the resin may be insufficient. If the peak intensity ratio "al / c" is less than 0.010, the surface treatment will be excessive, and the effect of the surface treatment will saturate, so the lower limit of the peak intensity ratio "al / c" is set to 0.010.

[0030] Alternatively, the surface state of the surface-treated inorganic particles according to this embodiment is such that, in the spectrum obtained by wide spectrum measurement using X-ray photoelectron spectroscopy (XPS), the peak intensity ratio "si / c" of the peak intensity "c" of the peak assigned to C1s and the peak intensity "si" of the peak assigned to Si2p per specific surface area is 0.010 or more and 0.300 or less. When the peak intensity ratio "si / c" is 0.010 or more and 0.300 or less, the balance between the hydrophilicity and hydrophobicity of the surface of the inorganic particles is in a suitable range, and the mutual adhesion when the particles are mixed with a resin can be made suitable. When the peak intensity ratio "si / c" is more than 0.300, the surface treatment is insufficient, and the hydrophilicity of the surface of the inorganic particles may not be improved (maintained). In other words, the adhesion between the particles and the resin may be insufficient. If the peak intensity ratio "si / c" is less than 0.010, the surface treatment will be excessive, and the effect of the surface treatment will be saturated, so the lower limit of the peak intensity ratio "si / c" is set to 0.010.

[0031] Alternatively, the surface state of the surface-treated inorganic particles according to this embodiment is such that, in the spectrum obtained by wide spectrum measurement using X-ray photoelectron spectroscopy (XPS), the peak intensity ratio "n / c" of the peak intensity "c" of the peak assigned to C1s and the peak intensity "n" of the peak assigned to N1s per specific surface area is 0.010 or more and 0.250 or less. When the peak intensity ratio "n / c" is 0.010 or more and 0.250 or less, the balance between the hydrophilicity and hydrophobicity of the surface of the inorganic particles is in a suitable range, and the mutual adhesion when the particles are mixed with a resin can be made suitable. When the peak intensity ratio "n / c" is more than 0.250, the surface treatment is insufficient, and the hydrophilicity of the surface of the inorganic particles may not be improved (maintained). In other words, the adhesion between the particles and the resin may be insufficient. If the peak intensity ratio "n / c" is less than 0.010, the surface treatment will be excessive, and the effect of the surface treatment will saturate, so the lower limit of the peak intensity ratio "n / c" is set to 0.010.

[0032] (Average particle size) The surface-treated inorganic particles according to one embodiment of the present invention have an average particle size of 0.1 μm or more and 180.0 μm or less. If the average particle size is less than 0.1 μm, the particles tend to aggregate more, which is undesirable because the fluidity of the resin composition when used as a filler is significantly reduced. If the average particle size exceeds 180.0 μm, the particles may get caught in the narrow space between the mounting substrate and the chip in semiconductor packages that are becoming smaller and thinner, which may reduce the fluidity of the liquid encapsulant and reduce moldability.

[0033] Here, the average particle size refers to the average particle size (D50), and means the median diameter D50 at 50% cumulative volume in a volume-based particle size distribution measured by a laser diffraction / scattering particle size distribution measurement method. The laser diffraction / scattering particle size distribution measurement method involves irradiating a dispersion in which surface-treated inorganic particles are dispersed with laser light, and determining the particle size distribution from the intensity distribution pattern of the diffracted / scattered light emitted from the dispersion. In the present invention, a laser diffraction / scattering particle size distribution measurement device "Mastersizer 3000" (manufactured by Malvern) is used. The average particle size of the raw material of the surface-treated inorganic particles can also be determined in a similar manner.

[0034] (Specific Surface Area) In one embodiment of the present invention, the surface-treated inorganic particles have a specific surface area of ​​0.1 m ２ / g or more 5.00m ２ / g or less.

[0035] The specific surface area of ​​the surface-treated inorganic particles is 0.1 m ２ If the specific surface area of ​​the spherical particles is less than 5.00 m / g, the particles are unlikely to form a close-packed structure, and the fluidity of the liquid encapsulant containing the particles may decrease. ２ If the particle size exceeds 1 / g, the tendency for aggregation between particles increases, which may also reduce the fluidity of the liquid encapsulant.

[0036] The specific surface area of ​​the surface-treated inorganic particles was measured by the BET method, which applies the BET theory to an adsorption isotherm measured by a gas adsorption method. A specific surface area measuring device, "Maxsorb Model HM-1208" manufactured by Mountech Co., Ltd., was used for the measurement. Typically, the specific surface area is measured using the following procedure. Approximately 5 g of sample was weighed out and vacuum dried at 250°C for 5 minutes. Next, the sample was placed in a specific surface area measuring device ("Maxsorb Model HM-1208" manufactured by Mountech Co., Ltd.), and the nitrogen gas adsorption amount was measured at a measurement temperature of 77 K using pure nitrogen and a nitrogen-helium mixed gas (mixture ratio: 30% nitrogen, 70% He) at a relative pressure P / P of 0.291, and the BET specific surface area was calculated using the single-point method.

[0037] (Circularity) In one embodiment of the present invention, the surface-treated inorganic particles may have a circularity of 0.85 or more. The higher the circularity of the surface-treated inorganic particles, the lower the viscosity of the resin composite composition containing the particles and the more improved the moldability. The circularity may be 0.90 or more, 0.91 or more, 0.92 or more, or 0.93 or more. Theoretically, the upper limit of the circularity is 1.0, but from the viewpoint of production control, it may be 0.98 or less, or 0.95 or less.

[0038] The circularity can be measured using an electron microscope, an optical microscope, and an image analyzer. For example, Sysmex FPIA. These devices are used to measure the circularity of particles (perimeter of the equivalent circle / perimeter of the projected image of the particle). The circularity of 100 or more particles is measured, and the average value is taken as the circularity of the powder.

[0039] (Aggregation Degree) In one embodiment of the present invention, the surface-treated inorganic particles may have an aggregation degree of 1.0% or less. The aggregation degree here is an index indicating whether particles are aggregated, and is measured by a sieving measurement method. When an aqueous slurry (solvent: water) of the surface-treated inorganic particles is heated and dried, the particles aggregate to form large clumps. The aggregation requires disintegration to separate the particles. Disintegration results in equipment wear and costs due to contact with the disintegration device. Furthermore, aggregation of particles may result in insufficient dispersion in the resin, which may deteriorate the fluidity and viscosity of the resin composition. An aggregation degree of 1.0% or less means that there are few clumps, meaning that a disintegration process is unnecessary. From the above perspective, a lower aggregation degree is desirable, but since it is difficult to completely prevent aggregation, the lower limit may be 0.0001% or more.

[0040] The degree of agglomeration was measured as follows. Two standard sieves with mesh sizes of 4.75 mm and 212 μm were stacked in order. The 212 μm mesh sieve was placed at the bottom, and the sieves with increasingly larger mesh sizes were stacked on top of it. 50 g of sample (a heated and dried aqueous slurry of surface-treated inorganic particles) was placed on the top 4.75 mm mesh sieve and set in a sieve shaker. The sieve shaker used was an OCTAGON 200 manufactured by Endecotts. After the sieves were set, the vibration amplitude was set to 5 and the shaking time was set to 3 minutes. After shaking was completed, the weight of the particles remaining on each sieve mesh and the particles that passed through the 212 μm mesh were measured. If the amount of particles on the 4.75 mm mesh is Ag, the amount of particles on the 212 μm mesh is Bg, and the amount of particles that passed through the 212 μm mesh is Cg, then the degree of aggregation is calculated as A / (B+C)×100(%).

[0041] (Residual Solvent Amount) In one embodiment of the present invention, the surface-treated inorganic particles may have a weight loss rate of 5.0% or less when heated from room temperature to 200°C, as measured by gravimetry. If the solvent used during surface treatment remains on the particle surface, it may react with the resin when mixed with the resin, causing curing inhibition. Furthermore, when used as a filler for a liquid encapsulant, the solvent remaining on the particle surface may volatilize due to the heat generated when the encapsulant is cured, potentially causing voids to form within the encapsulant. From the above perspective, the smaller the residual solvent amount, the better, and it may be 3.0% or less, or even 2.0% or less. However, if the surface-treated inorganic particles are dried at high temperatures to reduce the residual amount, the treatment agent may oxidize, potentially preventing the desired effect from being achieved. Therefore, the lower limit may be 0.1% or more, preferably 0.01% or more.

[0042] The amount of solvent remaining on the surface is measured as follows: Approximately 10 g of surface-treated inorganic particles are placed in a crucible and heated for 2 hours in a heating furnace heated to 200°C. After heating, the particles are allowed to cool in a desiccator containing a desiccant, and then their weight is measured. The amount of weight loss of the sample at this time is divided by the weight of the sample before heating to determine the amount of residual solvent (%).

[0043] (Inorganic Particles) The surface-treated inorganic particles, which are one embodiment of the present invention, are obtained by subjecting the surface of raw inorganic particles to a surface treatment. The material of the inorganic particles is not particularly limited as long as it is capable of being surface-treated, and may be at least one selected from amorphous silica, crystalline silica, alumina, titanium oxide, aluminum nitride, aluminum oxynitride, barium titanate, and magnesium oxide. Inorganic particles made of these listed materials can be suitably used as inorganic fillers. Furthermore, the surface-treated inorganic particles, which are one embodiment of the present invention, can achieve suitable adhesion when mixed with a resin. Note that it is possible to distinguish between inorganic particles that have not been surface-treated and surface-treated inorganic particles by, for example, surface analysis using XPS, followed by internal analysis in the depth direction while scraping the surface by irradiating with an argon ion beam or the like.

[0044] (Absorption spectrum by Fourier transform infrared spectrophotometer (FT-IR)) The surface-treated inorganic particles according to one embodiment of the present invention have an absorption spectrum of 3000 to 2800 cm by Fourier transform infrared spectrophotometer (FT-IR). －１ and 1665-1570 cm －１ The absorption spectrum may be detected by Fourier transform infrared spectroscopy (FT-IR). Information about the molecules and structure present on the surface of the surface-treated inorganic particles can be obtained by measurement with a Fourier transform infrared spectrophotometer (FT-IR). In other words, the amount and type of functional groups present that correspond to the desired properties can be estimated from the absorption spectrum, which is useful.

[0045] In one embodiment, the surface-treated inorganic particles have a viscosity of 2973 to 2872 cm －１ In one embodiment, the surface-treated inorganic particles have an absorption spectrum of 1660 to 1575 cm. －１ An absorption spectrum may be detected at 1000 nm, and it is inferred that amino groups are present on the surface of the surface-treated inorganic particles.

[0046] In one embodiment, the surface-treated alumina particles are surface-treated, and the surface-treated alumina particles have a viscosity of 1738 to 1728 cm －１ An absorption spectrum may be detected at 1115 to 1107 cm, which suggests that a carboxyl group is present on the surface of the surface-treated inorganic particles. －１ An absorption spectrum may be detected at 1000 nm, and it is inferred that ether groups are present on the surface of the surface-treated inorganic particles.

[0047] In one embodiment, the surface-treated silica particles are surface-treated silica particles. －１ An absorption spectrum may be detected at 1870-1860 cm －１ The absorption spectrum may be detected.

[0048] The method of Fourier transform infrared spectrophotometer (FT-IR) measurement is as follows. The surface-treated inorganic particles to be measured were diluted with KBr and tableted to prepare a measurement sample. The measurement was performed using a measuring device, Frontier manufactured by Perkin Elmer, and analysis software, Perkin Elmer Spectrum, with a resolution of 4 cm. ‐１ Measurement was carried out by the diffuse reflectance method under the condition of 16 scans.

[0049] [Resin composite composition] According to one embodiment of the present invention, a composite composition containing the above-described surface-treated inorganic particles and a resin can be produced. The composition of the resin composite composition will be described in more detail below.

[0050] Using a slurry composition containing surface-treated inorganic particles and a resin, it is possible to obtain a resin composite composition such as a semiconductor encapsulant (particularly a liquid encapsulant), an interlayer insulating film, etc. Furthermore, by curing these resin composite compositions, it is possible to obtain a resin composite such as an encapsulant (cured product), a substrate for semiconductor packaging, etc.

[0051] When producing the resin composite composition, for example, in addition to the surface-treated inorganic particles and resin, a curing agent, a curing accelerator, a flame retardant, an additive, etc. are blended as needed, and the resulting composite is formed by a known method such as kneading. The resulting composite is then molded into pellets, a film, or other shapes depending on the intended use. In this embodiment, there is no need to use agents such as silane coupling agents or silane agents, and the inconveniences associated with these agents can be avoided. Typically, agents such as silane coupling agents and silane agents can be used to avoid the time required for hydrolysis and undesirable polymerization of the agents after hydrolysis.

[0052] In addition to the surface-treated inorganic particles and the resin, other inorganic fillers may be blended when producing the resin composite composition. Examples of the inorganic fillers include amorphous spherical silica particles, crystalline spherical silica particles, titania particles, magnesia particles, aluminum nitride particles, boron nitride particles, barium titanate particles, calcium titanate particles, and carbon fibers. The blending ratio of the inorganic fillers can be adjusted appropriately depending on the application of the resin composite composition.

[0053] Furthermore, when the resin composite composition is cured to produce a resin composite, for example, the resin composite composition is heated to melt, processed into a shape appropriate for the intended use, and then heated to a temperature higher than that used for melting to completely cure it. In this case, a known method such as transfer molding can be used. Furthermore, the resin composite composition can have a suitably low thixotropy, which can increase the fluidity of the resin composite composition, making it suitable for use as a liquid encapsulant.

[0054] For example, when manufacturing semiconductor-related materials such as package substrates and interlayer insulating films, known resins can be used as the resin for the resin composite composition, but epoxy resins are preferred. The epoxy resin is not particularly limited, but examples include bisphenol A epoxy resins, bisphenol F epoxy resins, biphenyl epoxy resins, phenol novolac epoxy resins, cresol novolac epoxy resins, naphthalene epoxy resins, and phenoxy epoxy resins. One of these resins can be used alone, or two or more resins with different molecular weights can be used in combination. Among these, epoxy resins having two or more epoxy groups per molecule are preferred from the viewpoints of curability, heat resistance, and the like. Specific examples include biphenyl-type epoxy resins, phenol novolac-type epoxy resins, orthocresol novolac-type epoxy resins, epoxidized novolac resins of phenols and aldehydes, glycidyl ethers of bisphenol A, bisphenol F, bisphenol S, etc., glycidyl ester acid epoxy resins obtained by reacting polybasic acids such as phthalic acid or dimer acid with epochlorohydrin, linear aliphatic epoxy resins, alicyclic epoxy resins, heterocyclic epoxy resins, alkyl-modified polyfunctional epoxy resins, β-naphthol novolac-type epoxy resins, 1,6-dihydroxynaphthalene-type epoxy resins, 2,7-dihydroxynaphthalene-type epoxy resins, bishydroxybiphenyl-type epoxy resins, and epoxy resins into which halogens such as bromine have been introduced to impart flame retardancy. Among these epoxy resins having two or more epoxy groups per molecule, bisphenol A-type epoxy resins are particularly preferred.

[0055] Furthermore, resins other than epoxy resins can also be used as resin composite compositions for applications other than semiconductor encapsulation composite materials, such as prepregs for printed circuit boards and various engineering plastics. Specific examples of resins that can be used in addition to epoxy resins include silicone resins, phenolic resins, melamine resins, urea resins, unsaturated polyesters, fluororesins, polyamides such as polyimides, polyamideimides, and polyetherimides; polyesters such as polybutylene terephthalate and polyethylene terephthalate; polyphenylene sulfide, aromatic polyesters, polysulfones, liquid crystal polymers, polyethersulfones, polycarbonates, maleimide-modified resins, ABS resins, AAS (acrylonitrile-acrylic rubber-styrene) resins, and AES (acrylonitrile-ethylene-propylene-diene rubber-styrene) resins.

[0056] The curing agent used in the resin composite composition may be any known curing agent for curing the resin, such as a phenol-based curing agent, such as a phenol novolac resin, an alkylphenol novolac resin, or a polyvinylphenol, which may be used alone or in combination.

[0057] The amount of the phenolic curing agent blended is preferably such that the equivalent ratio to the epoxy resin (phenolic hydroxyl group equivalent / epoxy group equivalent) is 0.1 or more and less than 1.0, thereby eliminating any unreacted phenolic curing agent from remaining and improving moisture absorption and heat resistance.

[0058] The amount of the surface-treated inorganic particles added to the resin composite composition is preferably large from the viewpoints of heat resistance and thermal expansion coefficient, but is usually 70% by mass to 95% by mass, preferably 80% by mass to 95% by mass, and more preferably 85% by mass to 95% by mass. This is because if the amount of the surface-treated inorganic particles is too small, it is difficult to obtain effects such as improving the strength of the sealing material and suppressing thermal expansion, and conversely, if the amount is too large, segregation due to aggregation of the surface-treated inorganic particles is likely to occur in the composite material regardless of the surface treatment of the surface-treated inorganic particles, and the viscosity of the composite material will also become too high, making it difficult to use as a sealing material.

[0059] In addition to the resin, known additives such as a curing agent, a coloring agent, and a hardening retarder can be used.

[0060] A heat-dissipating sheet, heat-dissipating grease, etc. can be obtained using a slurry composition containing surface-treated inorganic particles and a resin.

[0061] When obtaining the heat dissipation sheet, the surface-treated inorganic particles, the resin, and additives are appropriately blended and compounded by a known method such as kneading, etc. The obtained composite is molded into a sheet by a known method.

[0062] For example, when producing a heat dissipation sheet, known resins can be used in the resin composite composition, including silicone resins, phenolic resins, melamine resins, urea resins, unsaturated polyesters, fluororesins, polyamides such as polyimides, polyamideimides, and polyetherimides; polyesters such as polybutylene terephthalate and polyethylene terephthalate; polyphenylene sulfide, aromatic polyesters, polysulfones, liquid crystal polymers, polyethersulfones, polycarbonates, maleimide-modified resins, ABS resins, AAS (acrylonitrile-acrylic rubber-styrene) resins, and AES (acrylonitrile-ethylene-propylene-diene rubber-styrene) resins. Among these, silicone resins are preferred. The silicone resin is not particularly limited, but examples include peroxide-curable, addition-curable, condensation-curable, and ultraviolet-curable resins.

[0063] In addition to the resin, known additives such as a curing agent, a coloring agent, and a hardening retarder can be used.

[0064] When preparing the thermally conductive grease, additives are appropriately blended in addition to the surface-treated inorganic particles and resin, and the resulting mixture is compounded by a known method such as kneading. The resin used in the thermally conductive grease is also called a base oil.

[0065] For example, when producing a thermally conductive grease, known resins can be used in the resin composite composition, and specific examples include silicone resins, phenolic resins, melamine resins, urea resins, unsaturated polyesters, fluororesins, polyamides such as polyimide, polyamideimide, and polyetherimide; polyesters such as polybutylene terephthalate and polyethylene terephthalate; polyphenylene sulfide, aromatic polyesters, polysulfones, liquid crystal polymers, polyethersulfones, polycarbonates, maleimide-modified resins, ABS resins, AAS (acrylonitrile-acrylic rubber-styrene) resins, AES (acrylonitrile-ethylene-propylene-diene rubber-styrene) resins, mineral oils, synthetic hydrocarbon oils, ester oils, polyglycol oils, silicone oils, and fluorine oils.

[0066] In addition to the resin, known additives such as colorants and thickeners can be used. Known thickeners that can be used include calcium soap, lithium soap, aluminum soap, calcium complex, aluminum complex, lithium complex, barium complex, bentonite, urea, PTFE, sodium terephthalamate, silica gel, and organic bentonite.

[0067] [Method for producing surface-treated inorganic particles] One embodiment of the present invention provides a method for producing surface-treated inorganic particles. This method is a method that can suitably produce the above-mentioned surface-treated inorganic particles and includes the following steps: (1) a surface treatment step of contacting the surfaces of inorganic particles with a diluent solution in which a graft polymer having an anionic functional group is dissolved in a diluent; and (2) a drying step of drying the inorganic particles that have been contacted with the diluent solution.

[0068] (Inorganic particles) As mentioned above, the inorganic particles that are the raw material for the surface-treated inorganic particles are not particularly limited as long as they can be surface-treated.The material of the inorganic particles is not particularly limited as long as they can be surface-treated, and may be at least one selected from amorphous silica, crystalline silica, alumina, titanium oxide, aluminum nitride, aluminum oxynitride, barium titanate, and magnesium oxide.These inorganic particles may be produced by known production methods, or may be commercially available products.

[0069] (Graft polymer having anionic functional groups) In this embodiment, the graft polymer has anionic functional groups, which can function as adsorption groups to the surface of inorganic particles. The graft polymer has a structure in which one polymer is bonded to another polymer as a side chain (graft), and the graft portion of the graft polymer adsorbed to the surface of the inorganic particles can provide a desired surface treatment effect. Typically, the balance between hydrophilicity and hydrophobicity of the surface of the inorganic particles can be set within a suitable range, thereby achieving favorable mutual adhesion when the particles are mixed with a resin. Furthermore, the addition of the three-dimensional structure of the graft portion to the surface of the inorganic particles makes it easier for inorganic particles to repel each other, thereby suppressing aggregation between the inorganic particles and improving the dispersibility of the inorganic particles when mixed with a resin.

[0070] (Diluent) The diluent is not particularly limited as long as it can dissolve the graft polymer having an anionic functional group to obtain a diluent solution (hereinafter also referred to as "diluent"). Examples of the diluent that can be used include water, organic solvents, ethanol, butyl cellosolve, terpineol, PGMEA (propylene glycol monomethyl ether acetate), toluene, benzene, acetone, and chloroform.

[0071] (Contact) A diluent in which a graft polymer having an anionic functional group is dissolved is brought into contact with the surface of the inorganic particles. This causes the graft polymer to adhere to the surface of the inorganic particles. The contact method is not particularly limited. The diluent may be sprayed onto the inorganic particles. Alternatively, the inorganic particles may be immersed in the diluent. Furthermore, the inorganic particles that have been contacted with the diluent may be mixed or stirred to allow the diluent to contact the surface of each inorganic particle more evenly. Various conditions, such as the amount and particle size of the inorganic particles, the concentration and amount of the diluent, and the mixing operation of the inorganic particles, may be appropriately adjusted, thereby adjusting the degree of surface treatment.

[0072] (Drying) The inorganic particles that have been brought into contact with the diluent solution are dried. This causes the solvent of the diluent to volatilize, and the surfaces of the inorganic particles are surface-treated with the graft polymer having an anionic functional group. In other words, surface-treated inorganic particles can be produced.

[0073] The process of spraying the diluent onto inorganic particles is sometimes called a dry process. In this dry process, the amount of the diluent sprayed can generally be small, and the time required for drying can be short, which is preferable from the viewpoint of production control. As a typical drying condition, the inorganic particles sprayed with the diluent may be heated at a temperature of several tens to several hundred degrees for several minutes to several tens of hours.

[0074] The process of immersing inorganic particles in a diluent is sometimes called a wet process. In this wet process, the amount of diluent attached to the inorganic particles (immersion amount) is generally greater than in a dry process, and the time required for drying may be longer. The drying conditions may be adjusted within the range of the typical conditions described above, such as by increasing the drying temperature or lengthening the drying time.

[0075] The present invention will be described below through examples and comparative examples, but the present invention should not be construed as being limited to the following examples.

[0076] As shown in Table 1, inorganic particles (alumina powder 1 to alumina powder 6, silica powder 1 to silica powder 2, aluminum nitride powder 1) were prepared as raw materials for the surface-treated inorganic particles.

[0077] Inorganic particles were produced as follows. The raw material for the inorganic particles was introduced into a high-temperature flame formed by LPG and oxygen, and a spheroidizing treatment was carried out. The flame formation conditions, raw material particle size, raw material supply amount, classification conditions, etc. were adjusted to produce inorganic particles having the physical properties of the inorganic particles (average particle size, specific surface area, circularity) shown in Table 1. Specifically, the particle size distribution was adjusted by adjusting the raw material particle size and by subjecting the powder after the spheroidizing treatment to multistage sieving and classification. Alternatively, suitable inorganic particles were procured from commercially available products.

[0078]

[0079] The physical properties of the obtained inorganic particles were measured by the following methods.

[0080] (Average particle size by laser diffraction scattering method) The laser diffraction / scattering particle size distribution measurement method is a method in which a dispersion liquid containing surface-treated inorganic particles is irradiated with laser light, and the particle size distribution is determined from the intensity distribution pattern of the diffracted / scattered light emitted from the dispersion liquid. In the present invention, a laser diffraction / scattering particle size distribution measurement device "Mastersizer 3000" (manufactured by Malvern) was used.

[0081] (Specific Surface Area) 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 device, "Macsorb Model HM-1208" manufactured by Mountech Co., Ltd.

[0082] (Circularity) Measurement of circularity was carried out using an automatic flow particle image imaging analyzer (FPIA) manufactured by Sysmex Corporation. Using this device, the circularity of the particles (perimeter of the equivalent circle / perimeter of the projected image of the particle) was measured. The circularity of 100 or more particles was measured, and the average value was taken as the circularity of the powder.

[0083] The inorganic particles shown in Table 1 were subjected to dry treatment or wet treatment as shown in Table 2 to prepare surface-treated inorganic particles.

[0084] The dry treatment procedure was as follows. (Preparation of Treatment Solution) The surface treatment agent for inorganic particles (hereinafter simply referred to as "treatment agent") used was the dispersant Marialim (registered trademark) and dispersant Sleem (registered trademark) manufactured by NOF Corporation, which are graft polymers having anionic functional groups. The product numbers are SC-0505K, AKM-0531, SC-0708A, SC-1015F, AFB-1521, AD-3172M, AD-374M, and AD-508E. Ethanol was used as the diluent. The amounts of the treatment agent and diluent listed in Table 2 were placed in a spray bottle, and the solution was shaken and stirred until the color of the solution became uniform, creating a treatment solution. (Method for Treating Inorganic Particles) The inorganic particles (alumina powder, silica powder, and aluminum nitride powder) listed as raw powder in Table 2 were placed in a zippered plastic bag (Unipack) in the amount of powder listed in Table 2. The inorganic particles placed in a plastic bag were sprayed with the treatment liquid prepared above in the amount shown in Table 2. After spraying, the inorganic particles were stirred in the plastic bag for 5 to 10 minutes, and then the inorganic particles were spread on a tray and dried in a dryer at 100°C for 5 hours to obtain surface-treated inorganic particles.

[0085] The wet treatment procedure was as follows: 1.2 kg of water was placed in a kitchen pot or a 2 L beaker, and inorganic particles (alumina powder) were added while stirring the water with a stirrer to prepare a slurry. A treatment agent (SC-0505K) was further added to this slurry, and after stirring, the slurry was placed in a tray and heated and dried at 120°C for 30 hours to obtain surface-treated inorganic particles.

[0086]

[0087] The obtained surface-treated inorganic particles were subjected to the following XPS analysis. The results are shown in Table 2. The average particle size, specific surface area, and circularity of the obtained surface-treated inorganic particles were measured using the same methods as those for the raw inorganic particles. The average particle size, specific surface area, and circularity after the surface treatment were almost the same as those before the surface treatment. The surface-treated inorganic particles had an average particle size in the range of 0.1 to 180.0 μm and a specific surface area of ​​0.10 to 5.00 m. ２ / g and the circularity was in the range of 0.85 or more.

[0088] (Measurement of atomic composition ratio by XPS) XPS is a measurement method for qualitatively and quantitatively analyzing the chemical bonding state of a sample by irradiating a powder sample with X-rays and then analyzing the kinetic energy of photoelectrons excited by the photoelectric effect. In the present invention, a "PHI5000 VersaProbe II" (manufactured by ULVAC-PHI, Inc.) was used to measure a wide spectrum from 0 to 1100 eV. The atomic composition ratio was quantified from the area intensity ratio of each spectrum. Five types of spectra were used in the present invention: C1s, N1s, O1s, Al2p, and Si2p.

[0089] (Measurement of Peak Intensity Ratio by XPS) Of the spectra obtained by wide spectrum measurement, the peak intensity ratio a / c was calculated by (Al2p peak intensity per specific surface area) / (C1s peak intensity per specific surface area). Similarly, the peak intensity ratio s / c was calculated by (Si2p peak intensity per specific surface area) / (C1s peak intensity per specific surface area), and the peak intensity ratio n / c was calculated by (N1 peak intensity per specific surface area) / (C1s peak intensity per specific surface area). Table 2 shows the peak intensity ratios of surface-treated inorganic particles and non-surface-treated inorganic particles.

[0090] Using the obtained surface-treated inorganic particles, the flow rate was measured in the following manner.

[0091] (Method for Measuring Flow Rate) The flow rate was measured according to the following procedure. In the case of surface-treated alumina particles or a mixture thereof, 87 parts by mass of the particles and 13 parts by mass of an epoxy resin (Epicoat 801N) were mixed in a kneader. The resulting resin composition was cooled in a water bath for 60 minutes and then measured using a Shimadzu CFT-500D flow tester. Furthermore, when measuring surface-treated inorganic particles (silica powder series), 80 parts by mass of the surface-treated inorganic particles (silica powder) or a mixture thereof were mixed with 20 parts by mass of an epoxy resin (Epicoat 801N, manufactured by Mitsubishi Chemical Corporation) in a vacuum kneader. The resulting resin composition was cooled in a water bath for 30 minutes, and then measured using a Shimadzu CFT-500D flow tester. Approximately 10 ml of the kneaded sample was extruded at a temperature of 28.5°C through a die with a diameter of 2.0 mm and a length of 75.0 mm. The extrusion load was 50.0 kgf, and the discharge rate (ml / sec) was measured from the time when approximately 50% of the sample was extruded to the time when 75% was extruded. As a comparative example, the flow rate was also measured in the same manner for inorganic particles or mixtures thereof that had not been surface-treated.

[0092] The measurement results of the flow rate are shown in Table 3. The flow rate can be regarded as an index of fluidity. The higher the flow rate, the higher the fluidity. When the surface-treated inorganic particles were used (Example), the flow rate was almost the same as or increased compared to when the non-surface-treated inorganic particles were used (Comparative Example). In other words, it was confirmed that the surface-treated inorganic particles or the resin composition containing them according to the present invention improve fluidity.

[0093]

[0094] Using the obtained surface-treated inorganic particles, thixotropy was measured in the following manner.

[0095] (Measurement of Thixotropy) 87 parts by mass of surface-treated inorganic particles (alumina powder series) or a mixture thereof and 13 parts by mass of epoxy resin (Epicoat 801N manufactured by Mitsubishi Chemical Corporation) were mixed in a vacuum kneader, and the resulting resin composition was cooled in a water bath for 30 minutes. Then, the rotational viscosity was measured using a rheometer (MCR-101 manufactured by Anton Paar) with 25 mm parallel plates, a gap of 0.5 mm, and a temperature of 25°C, while changing the shear rate. Furthermore, when measuring the surface-treated inorganic particles (silica powder series), 80 parts by mass of the surface-treated inorganic particles (silica powder) or a mixture thereof and 20 parts by mass of an epoxy resin (Epikote 801N manufactured by Mitsubishi Chemical Corporation) or a silicone resin (CY-52-276A manufactured by Toray Dow Corning Co., Ltd.) were mixed in a vacuum kneader, and the resulting resin composition was cooled in a water bath for 30 minutes. Thereafter, the rotational viscosity was measured using a rheometer (MCR-101 manufactured by Anton Paar) with 50 mm diameter parallel plates, a gap of 1.0 mm, and a temperature of 25°C, while varying the shear rate.

[0096] Table 4 lists two types of viscosities at shear rates of 1 [1 / s] and 10 [1 / s]. The thixotropic ratio is the ratio of the two types of viscosities (viscosity at high shear rate / viscosity at low shear rate), and the closer it is to 1.0, the less the viscosity changes at both low and high shear rates. When surface-treated inorganic particles were used (Examples), the thixotropy decreased compared to when non-surface-treated inorganic particles were used (Comparative Examples), reaching a value nearly 1.0. In other words, it was confirmed that the surface-treated inorganic particles or the resin composition containing them according to the present invention reduce thixotropy.

[0097]

[0098] The dispersibility of the obtained surface-treated inorganic particles was evaluated in the following manner.

[0099] (Evaluation of Dispersibility) The surface-treated inorganic particles were mixed as powders 1 and 2 according to the powder blending ratios listed in Table 5. The mixed powders were then mixed with silicone resin (CY-52-276A, manufactured by Toray Dow Corning Co., Ltd.). The powder to resin mixing ratio was 70% by mass powder and 30% by mass resin. Vacuum mixing was performed using a foam mixer "ARV-310P" (manufactured by Thinky Corporation). The mixing conditions were 15 seconds of premixing and 90 seconds of vacuum mixing. The mixed compound was placed in a glass container approximately 20 mm in diameter and 90 mm in height, and the container was capped and allowed to stand. The liquid level of the compound immediately after standing was marked on the container with a marker. After standing for one month at room temperature of 20 to 25°C, the liquid level of the compound was read. The compound separated into resin and filler after standing for one month. Upon separation, the supernatant was transparent, while the filler settled area was cloudy. The liquid level of the compound after standing for one month was read as the cloudy upper surface of the filler settled area, i.e., the boundary between the cloudy area and the transparent supernatant. The difference between the liquid level of the compound immediately after mixing and the liquid level of the compound after standing for one month was measured, and the evaluation was carried out as follows: ◯ if it was 5 mm or less, △ if it was 5 mm to 10 mm, and × if it was 10 mm or more.

[0100] The resin compositions containing the surface-treated inorganic particles according to the present invention were evaluated for dispersibility as ○ or △, whereas the resin compositions not containing the surface-treated inorganic particles were evaluated for dispersibility as ×. In other words, it was confirmed that the resin compositions containing the surface-treated inorganic particles according to the present invention have improved dispersibility.

[0101]

Claims

1. As measured by X-ray photoelectron spectroscopy (XPS), the peak intensity ratio al / c of ​​the peak intensity c of the peak attributed to C1s to the peak intensity al of the peak attributed to Al2p is 0.010 to 0.500, the peak intensity ratio si / c of ​​the peak intensity c of the peak attributed to C1s to the peak intensity si of the peak attributed to Si2p is 0.010 to 0.300, or the peak intensity ratio n / c of ​​the peak intensity c of the peak attributed to C1s to the peak intensity n of the peak attributed to N1s is 0.010 to 0.250, the average particle size is 0.1 to 180.0 μm, and the specific surface area is 0.10 to 5.00 m ２ / g.

2. The surface-treated inorganic particles according to claim 1, having a circularity of 0.85 or more.

3. The surface-treated inorganic particles according to claim 1, having a degree of aggregation of 1.0% or less.

4. The surface-treated inorganic particles according to claim 1, which exhibit a weight loss rate of 5.0% or less when heated from room temperature to 200°C as measured by gravimetry.

5. The surface-treated inorganic particles according to claim 1, which are at least one selected from the group consisting of amorphous silica, crystalline silica, alumina, titanium oxide, aluminum nitride, aluminum oxynitride, barium titanate, and magnesium oxide.

6. Fourier transform infrared spectrophotometer (FT-IR) measurement shows a peak at 3000-2800 cm －１ and 1665-1570 cm －１ The surface-treated inorganic particles according to claim 1 , wherein an absorption spectrum is detected at 7. A resin composite composition comprising the surface-treated inorganic particles according to claim 1.

8. A method for producing surface-treated inorganic particles according to claim 1, comprising: a surface treatment step of contacting the surfaces of inorganic particles with a diluent solution in which a graft polymer having an anionic functional group is dissolved in a diluent; and a drying step of drying the inorganic particles that have been contacted with the diluent solution.

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