Slurry composition

Abstract

To provide a slurry composition containing spherical alumina particles that exhibit excellent fluidity in confined spaces. [Solution] Among the particles between 1 μm and 30 μm detected by a Coulter counter, the number frequency of particles 5 μm or larger is between 300 ppm and 20,000 ppm, the number frequency of particles 10 μm or larger is 50 ppm or less, and the specific surface area measured by the BET method is 2.0 m². 2 / g or more 10.0m 2 A slurry composition containing spherical alumina particles in a quantity of less than / g.

Description

[Technical Field]

[0001] The present invention relates to a slurry composition obtained by dispersing spherical alumina particles in a dispersion medium, particularly a slurry composition in which, among particles between 1 μm and 30 μm detected by a Coulter counter, the number frequency of particles 5 μm or larger is between 300 ppm and 20,000 ppm, the number frequency of particles 10 μm or larger is 50 ppm or less, and the specific surface area measured by the BET method is 2.0 m². 2 / g or more 10.0m 2 This invention relates to a slurry composition comprising spherical alumina particles, which have excellent fluidity due to being less than or equal to / g, dispersed in a dispersion medium. [Background technology]

[0002] In recent years, semiconductor packages used in electronic components and communication equipment have become smaller and thinner, and consequently, there is a growing need for miniaturization of substrate materials such as semiconductor encapsulants and insulating layers of package substrates. For these semiconductor components, it is common to use resin compositions in which fillers are filled into resin materials to control the coefficient of thermal expansion in order to provide mechanical strength and suppress warping. Methods for manufacturing such resin compositions include kneading dried fillers with matrix resin using a kneader or a three-roll kneader, as well as dispersing the fillers in a dispersion medium, mixing the resulting slurry with the matrix resin, and removing the dispersion medium by heat treatment to obtain a resin composition in which the fillers are dispersed in the resin material. This method has advantages over methods in which fillers and resins are directly kneaded, such as being able to uniformly disperse the fillers in the resin material.

[0003] Thus, slurry compositions or their fillers used in semiconductor peripheral components are being studied from various perspectives, such as fluidity, packing properties, and dispersibility.

[0004] For example, Patent Document 1 proposes that, in order to obtain high fluidity in the resin composite composition as described above, the filler is first dispersed in a solvent and then mixed with the resin in a slurry state, thereby enabling good dispersion of the filler into the resin. Specifically, it proposes appropriately adjusting the particle size distribution and specific surface area of ​​the oxide powder (filler) contained in the resin composite composition. More specifically, it discloses a slurry in which alumina with an average particle size of 0.7 μm is well dispersed at 70 wt%.

[0005] Furthermore, Patent Document 2 discloses an alumina slurry in which spherical alumina particles are coated with a phenolic resin and then formed into a slurry, thereby improving dispersibility in a polyamide-imide resin.

[0006] Furthermore, Patent Document 3 discloses that when dispersing spherical alumina in a solvent, the aggregation of amorphous particles can be suppressed by using beads of a specific size during the dispersion process, and that coating the film with this slurry improves the properties of the optical film as a viewing angle improving film.

[0007] However, there is a need for further improvement in the properties of resin composite compositions or inorganic particle-containing slurry compositions used in semiconductor peripheral materials. In particular, with the recent miniaturization of semiconductor packages, there is a demand for smaller particle sizes of fillers used in semiconductor encapsulants and substrate materials. On the other hand, the reduced particle size leads to problems such as decreased fluidity of the slurry composition, resulting in poor workability and a decline in the performance of the resin composition. Specifically, this has caused problems such as reduced penetration in narrow spaces such as glass cloth and poor dispersion of fillers within the resin composition. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2002-285003 [Patent Document 2] Japanese Patent Publication No. 2004-99829 [Patent Document 3] Japanese Patent Publication No. 2021-175702 [Overview of the project] [Problems that the invention aims to solve]

[0009] The present invention has been made in view of the above circumstances, and its object is to provide a slurry composition containing spherical alumina particles that exhibits excellent fluidity in confined spaces. [Means for solving the problem]

[0010] The inventors have found that the above problem can be solved by precisely cutting coarse particles in the particle size distribution of spherical alumina particles contained in the slurry, and more specifically by limiting the number of coarse particles having a particle size above a certain size.

[0011] Based on the above findings, the gist of the present invention is as follows.

[0012] [1] A slurry composition comprising spherical alumina particles and a dispersion medium, wherein the spherical alumina particles, among those detected by a Coulter counter between 1 μm and 30 μm in size, have a number frequency of particles 5 μm or larger between 300 ppm and 20,000 ppm, a number frequency of particles 10 μm or larger between 50 ppm and 30 μm, and a specific surface area of ​​5.0 m² as measured by the BET method. 2 / g or more 10.0m 2 A slurry composition characterized by having a concentration of less than or equal to / g. [2] The slurry composition according to [1], wherein the spherical alumina particles are surface-treated with a silane coupling agent. [3] The slurry composition according to [1] or [2], wherein the spherical alumina particles have a D50 of 0.4 μm or more and 3.0 μm or less as determined by laser diffraction scattering. [4] The slurry composition according to any one of [1] to [3], wherein the circularity of the spherical alumina particles is 0.85 or greater. [5] The slurry composition according to any one of [1] to [4], wherein among the particles of 1 μm or more and 30 μm or less detected by a Coulter counter, the particles of 20 μm or more are less than 10 ppm. [6] The slurry composition according to any one of [1] to [5], wherein when a glass cloth having a thickness of 0.09 mm and a size of 8 cm square is impregnated with 5 mL of the slurry composition for 30 seconds and then pulled up and dried at 180 ° C for 1 h, the weight increase of the glass cloth is 0.2 g or more. [7] The slurry composition according to any one of [1] to [6], further containing at least one type of inorganic filler selected from 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. [8] The slurry composition according to any one of [1] to [7], wherein the relative permittivity of the dispersion medium is 5 to 30. [Effect of the Invention]

[0013] The spherical alumina particle-containing slurry composition according to the present invention and the resin composite composition produced using the same have the particle size distribution of the spherical alumina particles, particularly the number frequency of particles of 5 μm or more and the number frequency of particles of 10 μm or more, controlled in a specific region. Therefore, the slurry composition does not contain coarse particles and has excellent fluidity and permeability in a narrow space. As a result, the defective rate in recent small or thin semiconductor products or circuit board insulating layers can be reduced. [Brief Description of the Drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram of a mold for measuring fluidity. [Modes for Carrying Out the Invention]

[0015] The spherical alumina particles constituting the slurry composition of the present invention are Among the particles between 1 μm and 30 μm detected by the Coulter counter, the number frequency of particles 5 μm or larger is between 300 ppm and 20,000 ppm, the number frequency of particles 10 μm or larger is 50 ppm or less, and the specific surface area measured by the BET method is 2.0 m². 2 / g or more 10.0m 2 It is less than / g.

[0016] The Coulter counter measures particles using an electrical resistance method called the Coulter principle. Unlike optical measurement methods, it avoids errors related to particle surface morphology, internal structure, refractive index, and color, resulting in high measurement accuracy. In particular, the particle size obtained by this method can be expressed as a number distribution, enabling precise control of particle size distribution.

[0017] Spherical alumina particles and 150 mL of electrolyte were placed in a 200 mL glass beaker and dispersed for 30 seconds using an ultrasonic homogenizer (SMT, ULTRA SONIC HOMOGENIZER UH-300). This dispersion was then added to electrolyte prepared in another beaker to adjust the concentration. The individual particle sizes of the spherical alumina particles were measured using a Coulter counter (Beckman Coulter, Multisizer 4) with an aperture diameter of 50 μm. Approximately 100,000 particles were measured per measurement, and the same sample was measured three times. Of the particles between 1 μm and 30 μm detected by the Coulter counter, the number of particles with particle sizes of 5, 10, and 20 μm or larger was calculated and expressed as the respective coarse particle frequencies (ppm) relative to the total number of particles measured.

[0018] Measurements using this Coulter counter show that the frequency of particles 3 μm or larger relative to the total number of spherical alumina particles between 1 μm and 30 μm is between 300 ppm and 20,000 ppm, and the frequency (proportion) of coarse particles 10 μm or larger is 50 ppm or less. 50 ppm or less means, for example, that when there are 100,000 particles between 1 μm and 30 μm, there are 5 or fewer particles 10 μm or larger. The inventors have found that when the frequency of coarse particles 10 μm or larger exceeds 50 ppm, such coarse particles can clog in the narrow space between the mounting substrate and the chip, reducing fluidity, and as a result, the defect rate in semiconductor products filled with these particles can be reduced.

[0019] A lower frequency of coarse particles larger than 10 μm is preferable because it improves fluidity. Therefore, the frequency may be 40 ppm or less, 30 ppm or less, 20 ppm or less, or 10 ppm or less. The frequency of coarse particles larger than 10 μm may be 0 ppm, but completely eliminating such coarse particles, i.e., making it 0 ppm, can be difficult and burdensome for manufacturing control, so it may be a few ppm, specifically 1 ppm or more, or 5 ppm or more. The lower limit of the frequency may be adjusted according to the actual application and the acceptable range of the target yield, for example, 3 ppm or more, or 5 ppm or more.

[0020] On the other hand, the number frequency of coarse particles larger than 5 μm needs to be controlled to adequately ensure the fluidity of the resin composite composition. If the number frequency is less than 300 ppm, there will be many particles with a large specific surface area of ​​less than 5 μm, increasing viscosity and thus reducing fluidity. Conversely, if the number frequency exceeds 20,000 ppm, it will be difficult to prevent the inclusion of particles larger than 5 μm, causing clogging in the narrow space between the mounting substrate and the chip, and reducing fluidity. The preferred upper limit for this number frequency is 15,000 ppm, more preferably 10,000 ppm. The preferred lower limit for this number frequency is 5,000 ppm, more preferably 1,000 ppm, and even more preferably 500 ppm.

[0021] Furthermore, among the particles between 1 μm and 30 μm detected by the Coulter counter, it is preferable that the number frequency of particles 20 μm or larger is less than 10 ppm. A lower number frequency of coarse particles 20 μm or larger is preferable because it improves fluidity. If the number frequency of coarse particles 20 μm or larger is 10 ppm or higher, such coarse particles will clog in the narrow space between the mounting substrate and the chip, reducing fluidity. More preferably, it is less than 8 ppm, even more preferably less than 5 ppm, even more preferably less than 3 ppm, and most preferably zero.

[0022] The spherical alumina particles used in the slurry composition of the present invention can be produced by methods such as thermal spraying. In thermal spraying, calcined alumina or aluminum hydroxide powder, which has been crushed and adjusted to a desired particle size, is passed through a flame, causing the particles to melt and become spherical due to surface tension. By such thermal spraying, spherical alumina particles with a circularity of 0.80 or higher, preferably 0.85 or higher, can be produced. They can also be obtained by burning metal. For example, metallic aluminum powder can be used with a carrier gas to form a chemical flame in an oxygen-containing atmosphere, and fine particles of the desired alumina (Al2O3) can be obtained in this chemical flame. The degree of crystallinity can be controlled by the heat treatment conditions (melting of particles, cooling, etc.) in the manufacturing process of the spherical alumina particles.

[0023] Classification may be performed to obtain spherical alumina particles with a desired particle size distribution. Conventional known methods can be used for classification, and either wet classification or dry classification may be employed. Furthermore, gravity field classification, inertial force field classification, or centrifugal force field classification may be used. In the case of centrifugal force field classification, either free vortex type or forced vortex type classification may be used. Preferably, for example, a method can be exemplified by using a precision air classifier (also called an "air classifier") to cut off the coarse powder side and the fine powder side. However, in the present invention, the number frequency is measured using a Coulter counter in the classification control, and by precisely controlling the particle size distribution, it is possible to contribute to the excellent properties of the slurry composition of the present invention, such as fluidity in a narrow space.

[0024] Furthermore, spherical alumina particles may be used in mixture with other inorganic fillers to the extent that the desired properties can be obtained. These other inorganic fillers include not only those of different types, such as silica powder, magnesia powder, and titania powder, but also those with different particle size distributions. The types of other inorganic fillers will be described later.

[0025] In one embodiment of the present invention, the spherical alumina particles may have a D50 of 0.4 μm or more and 3.0 μm or less as determined by laser diffraction scattering.

[0026] The particle size distribution of spherical alumina particles can also be measured using laser diffraction scattering, and a particle size distribution analyzer such as the "Mastersizer3000" (manufactured by Malvern) can be used for this purpose. For measurement, a refractive index of 1.33 is used for the solvent (water), and the refractive index of the powder material is considered. For example, for alumina, a refractive index of 1.78 is used for measurement.

[0027] D50 (median diameter) refers to the particle size at which the cumulative volume in the cumulative particle size distribution of spherical alumina particles reaches 50%. D100 (maximum particle size) refers to the particle size at which the cumulative volume in the cumulative particle size distribution of spherical alumina particles reaches 100%.

[0028] If D50 is less than 0.4 μm, the particle size is small, and the viscosity of the slurry composition containing these particles, and the encapsulant which is a form of resin composite composition using the same, may become too high. On the other hand, if D50 is greater than 3.0 μm, problems may arise such as particles settling during storage, filling, or curing of the slurry or encapsulant, or the inclusion of many particles larger than 3 μm may cause the particles to get stuck in the narrow space between the mounting substrate and the chip, resulting in poor fluidity of the encapsulant and reduced moldability. A more preferable lower limit is 1.0 μm. On the other hand, a more preferable upper limit is 2.0 μm.

[0029] The spherical alumina particles used in the slurry composition of the present invention have a specific surface area of ​​2.0 m² as measured by the BET method. 2 / g or more 10.0m2 is less than / g.

[0030] The specific surface area of the spherical alumina particles can also be measured by the BET method. As a specific surface area measuring instrument, the product name "Macsorb Model HM-1208" manufactured by Mounttech is used for measurement.

[0031] When the specific surface area of the spherical alumina particles is less than 2.0 m 2 / g, it becomes difficult for the particles to form a close-packed structure, and thus the fluidity of the slurry composition of the present invention or the sealing material containing the slurry composition may decrease. Preferably, the specific surface area may be 2.3 m 2 / g or more, and may be 2.5 m 2 / g or more. On the other hand, when the specific surface area of the spherical alumina particles exceeds 10.0 m 2 / g, the tendency of aggregation between particles increases, and similarly, the fluidity of the slurry composition or the sealing material may decrease. Preferably, the specific surface area may be 8.0 m 2 / g or less, and may be 6.0 m 2 / g or less.

[0032] In one embodiment of the present invention, the spherical alumina particles may have a circularity of 0.85 or more. The higher the circularity of the spherical alumina particles, the lower the viscosity of the resin composite composition containing the particles, and the better the moldability can be improved. The circularity may be 0.90 or more, and may be 0.93 or more. The upper limit of the circularity is theoretically 1.0, but from the perspective of production management, it may be 0.98 or less, or 0.95 or less.

[0033] The circularity can be measured using an electron microscope, an optical microscope, and an image analysis device. For example, FPIA manufactured by Sysmex. Using these devices, the circularity (circumference of the equivalent circle / circumference of the projection image of the particle) of the particles is measured. Measure the circularity of 100 or more particles, and take the average value as the circularity of the powder.

[0034] 〈Dispersion medium〉 The dispersion medium used in the slurry composition of the present invention preferably has a dielectric constant in the range of 5 to 30, with more preferable lower limits of 8, 10, and 12, and more preferable upper limits of 25 and 20. By using a dispersion medium with a dielectric constant in the above range, a slurry composition can be obtained that has high affinity between spherical alumina particles and the dispersion medium, excellent fluidity in a narrow space, and excellent dispersion stability. Examples include cyclohexanone (relative permittivity: 18.3 (20°C)), methyl ethyl ketone (relative permittivity: 18.5 (20°C)), acetone (relative permittivity: 20.7), methyl isobutyl ketone (relative permittivity: 13.1 (20°C)), tetrahydrofuran (relative permittivity: 7.6 (25°C)), ethanol (relative permittivity: 24.6 (25°C)), cyclohexane (relative permittivity: 20.1 (20°C)), and 2-propanol (relative permittivity: 19.9 (25°C)).

[0035] <Method for preparing slurry> The slurry composition of the present invention can be prepared by dispersing the above-mentioned spherical alumina particle powder using a known dispersion method. Specifically, this can be done using equipment such as a three-roll mill, bead mill, ball mill, ultrasonic disperser, various mixers, kneader, and high-pressure wet atomizer.

[0036] The spherical alumina particle content in the slurry composition should preferably be between 30 and 95 wt%. If the filler content is less than 30 wt%, the viscosity of the slurry composition will decrease, and the settling stability of the filler within the slurry composition will be reduced, which is undesirable. If the spherical alumina particle content exceeds 95 wt%, the viscosity will increase, and the fluidity will be impaired.

[0037] <Surface treatment of spherical alumina particles> The spherical alumina particles contained in the slurry composition of the present invention are preferably treated with a silane compound. Examples include compounds having at least one functional group selected from alkyl groups such as methyl, ethyl, propyl, and butyl groups, alkenyl groups such as vinyl, ethenyl, and propenyl groups, phenyl, amino, phenylamino, acrylic, methacrylic, epoxy, and styryl groups, silane coupling agents, and silazanes. Examples of silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane. Examples of alkoxysilane compounds include hexyltrimethoxysilane, octyltriethoxysilane, and phenyltriethoxysilane. Examples of silazane compounds include hexamethyldisilazane and trimethylsilane. Treatment with silane compounds improves the affinity between the filler and the dispersion medium, resulting in good fluidity. In addition, resin compositions produced using slurry compositions also show improved high-filling properties due to improved adhesion with the matrix resin. As a surface treatment method, the filler-containing slurry composition of the present invention may be prepared using a filler that has undergone the above treatment in advance, or, depending on the surface treatment agent, it may be performed simultaneously with the preparation of the slurry composition. On the other hand, when spherical alumina particles are not surface-treated, the resin composition has superior strength, and the manufacturing flow is simpler, making it preferable from a cost and production management perspective.

[0038] <Dispersant> In addition to the silane compound mentioned above, a dispersant may be added to the slurry composition to provide dispersion stability. One type of dispersant may be used, or multiple dispersants may be used in combination.

[0039] Examples of dispersants include those comprising at least one selected from nonionic dispersants and cationic dispersants. There are no particular limitations on the nonionic dispersant, and known dispersants can be used. Examples include polymer compounds having polyoxyethylene chains. Examples of polymer compounds having polyoxyethylene chains include alkyl polyoxyethylene ethers, alkyl polyoxyethylene-polyoxypropylene ethers, alkyl polyoxypropylene-polyoxyethylene ethers, polyoxyethylene-polyoxypropylene ethers (polyoxyethylene oxypropylene block copolymers), fatty acid polyoxyethylene esters, fatty acid polyoxyethylene sorbitan esters, fatty acid polyoxyethylene sorbitol esters, polyoxyethylene sorbitan monoalkyl ethers, polyoxyethylene alkyl ether sulfate esters, polyoxyethylene castor oil (hydrogenated castor oil), acetylene glycol ethylene oxide adducts, etc. Examples of alkyl polyoxyethylene ethers include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octyl ether, polyoxyethylene cetyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether, etc. Examples of fatty acid polyoxyethylene sorbitan esters include polyoxyethylene sorbitan monolaurate.

[0040] There are no particular limitations on the cationic dispersant, and known ones can be used. Examples include alkylamine salts, acylamine salts, quaternary ammonium salts, ammonium salts having amide, ester, or ether bonds, imidazoline, imidazolium salts, and amine derivatives. The cationic dispersant may be a low molecular weight compound or a high molecular weight compound, but from the viewpoint of dispersibility of alumina particles, a high molecular weight compound is preferred. Examples of such high molecular weight dispersants include polyethyleneimine, aminoalkyl (meth)acrylate copolymers, polyvinylimidazoline, polyvinylpyridine derivatives, polyoxyethylene alkylamines, and polyoxyethylene alkylamides. Examples of polyvinylpyridine derivatives include copolymers of vinylpyridine and (meth)acrylic acid, and copolymers of vinylpyridine, (meth)acrylic acid, and oxyethylene group-containing high molecular weight compounds. Examples of copolymers of vinylpyridine, (meth)acrylic acid, and oxyethylene group-containing high molecular weight compounds include copolymers of vinylpyridine and (meth)acrylic acid and polyoxyethylene. Of these, amine-type high molecular weight dispersants are preferred from the viewpoint of dispersibility of alumina particles.

[0041] Furthermore, known surface treatment agents can be used as dispersants. Including a surface treatment agent improves the dispersibility between spherical alumina particles and the dispersion medium in slurry compositions, the dispersibility or affinity between the particles and the resin in resin composite compositions, and the dispersibility of spherical alumina particles in cosmetic compositions. Examples include compounds having at least one functional group selected from alkyl groups such as methyl, ethyl, propyl, and butyl groups, alkenyl groups such as vinyl, ethenyl, and propenyl groups, phenyl, amino, phenylamino, acrylic, methacrylic, epoxy, and styryl groups, silane coupling agents, and silazanes. More preferably, silane coupling agents having SiH, SiOH, or SiOR (where R is a hydrocarbon group) and silazanes of hexamethylenedisilazanes. Examples of silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane. Examples of alkoxysilane compounds include hexyltrimethoxysilane, octyltriethoxysilane, and phenyltriethoxysilane. Examples of silazane compounds include hexamethyldisilazane and trimethylsilane. From the viewpoint of superior reactivity, silazane compounds are more preferred. More preferably, they are hexamethyldisilazane and trimethylsilane.

[0042] The content of spherical alumina in the slurry composition (or the combined content of "inorganic fillers" or "other fillers" described later) can be appropriately adjusted depending on the application of the slurry composition. Typically, from the viewpoint of exhibiting the effect of spherical alumina particles, it is 50 to 95 wt%. A more preferred lower limit is 55 wt%, more preferably 60 wt%, more preferably 65 wt%, and more preferably 70 wt%. A more preferred upper limit is 93 wt%, more preferably 90 wt%, and more preferably 85 wt%.

[0043] <Dispersion in matrix resin and molding of molded products> The slurry composition of the present invention is used for dispersing fillers in a matrix resin during the molding of resin composite compositions. Specifically, the matrix resin is added to the slurry composition and mixed uniformly. Subsequently, by removing the dispersion medium through a treatment such as heating, a resin composite composition in which the fillers are uniformly dispersed in the resin can be prepared.

[0044] When manufacturing the aforementioned resin composite composition, for example, in addition to spherical alumina particles and matrix resin, curing agents, curing accelerators, flame retardants, silane coupling agents, etc., may be added as needed and compounded by known methods such as kneading. The composite can then be molded into pellets, films, or other forms depending on the application.

[0045] Furthermore, when manufacturing the resin composite composition, other inorganic fillers may be added in addition to spherical alumina particles and resin. Examples of such 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 fiber. The blending ratio of the inorganic fillers can be appropriately adjusted depending on the application of the resin composite composition, but from the viewpoint of exhibiting the effects of the spherical alumina particles of the present invention, it is preferable that (weight of spherical alumina particles):(weight of other inorganic fillers) = 95:5 to 60:40.

[0046] Furthermore, when curing the resin composite composition to produce a resin composite, for example, the resin composite composition can be heated and melted, processed into a shape suitable for the application, and then completely cured by applying a higher heat than that used during melting. In this case, known methods such as the transfer molding method or the compression molding method can be used.

[0047] For example, when manufacturing semiconductor-related materials such as packaging substrates and interlayer insulating films, known resins can be used as the resin in the resin composite composition, but epoxy resins are preferred. The epoxy resin is not particularly limited, but for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, naphthalene type epoxy resin, phenoxy type epoxy resin, etc., can be used. One of these can be used alone, or two or more with different molecular weights can be used in combination. Among these, epoxy resins having two or more epoxy groups in one molecule are preferred from the viewpoint of curability, heat resistance, etc. Specifically, 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 such as bisphenol A, bisphenol F, and bisphenol S, glycidyl ester epoxy resins obtained by the reaction of polybasic acids such as phthalic acid and 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 in one molecule, bisphenol A-type epoxy resins are particularly preferred.

[0048] Furthermore, resins other than epoxy resins can be used in applications other than composite materials for semiconductor encapsulants, such as prepregs for printed circuit boards and various engineering plastics. Specifically, in addition to epoxy resins, other resins include silicone resins, phenolic resins, melamine resins, urea resins, unsaturated polyesters, fluororesins, polyimides, polyamide-imides, polyetherimides and other polyamides; 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.

[0049] As a curing agent used in a resin composite composition, any known curing agent may be used to cure the resin, but for example, a phenolic curing agent can be used. As a phenolic curing agent, phenol novolac resins, alkylphenol novolac resins, polyvinylphenols, etc., can be used individually or in combination of two or more.

[0050] The amount of phenol curing agent blended is preferably such that its equivalent ratio to the epoxy resin (phenolic hydroxyl group equivalent / epoxy group equivalent) is 0.1 or more and less than 1.0. This eliminates the residue of unreacted phenol curing agent and improves moisture absorption and heat resistance.

[0051] The amount of spherical alumina particles added to the resin composite composition is preferably high from the viewpoint of heat resistance and thermal expansion coefficient, but is usually appropriate to be 70% to 95% by mass, preferably 80% to 95% by mass, and more preferably 85% to 95% by mass. This is because if the amount of spherical alumina particles is too low, it is difficult to obtain effects such as improved strength of the sealing material and suppression of thermal expansion, and conversely, if it is too high, segregation due to aggregation of spherical alumina particles is likely to occur in the composite material regardless of the surface treatment of the spherical alumina particles, and the viscosity of the composite material becomes too high, making it difficult to use as a sealing material. When the aforementioned "other fillers" are used in combination, the preferred amount added to the resin composite composition is the total amount of spherical alumina particles and "other fillers".

[0052] A method for producing spherical alumina particles contained in a slurry composition, which is one embodiment of the present invention, may include a step of melting calcined or electrofused alumina by introducing it into a flame, then cooling it to form spherical particles, and a step of classifying the particles after the spheroidizing step using a classifier (e.g., a precision wind classifier) ​​and / or a sieve. By this production method, among the particles of 1 μm to 30 μm detected by a Coulter counter, the number frequency of particles of 5 μm or more is 300 ppm to 20,000 ppm, the number frequency of particles of 10 μm or more is 50 ppm or less, and the specific surface area measured by the BET method is 2.0 m². 2 / g or more 10.0m 2 Spherical alumina particles with a weight of less than / g can be produced. [Examples]

[0053] The present invention will be described through the following examples and comparative examples. However, the present invention is not limited to the following examples.

[0054] <Method for manufacturing fillers> Calcined alumina was crushed, and the crushed material was fed into a high-temperature flame formed by the combustion of LPG and oxygen to perform a melting and spheroidizing treatment to obtain spherical alumina particles. Spherical alumina particles A to B shown in Table 1 were produced by adjusting the flame formation conditions, raw material particle size, raw material supply amount, classification conditions, and mixing conditions. Specifically, the particle size distribution was adjusted by adjusting the raw material particle size and by multi-stage sieving and classification operations of the powder after the spheroidizing treatment, and as a final step, classification was performed using a precision wind classifier. The number frequency of particles 5 and 10 μm or larger among the particles between 1 μm and 30 μm detected by a Coulter counter, D50 (or mode diameter) by laser diffraction scattering method, specific surface area and circularity measured by the BET method, etc., were adjusted by adjusting the mixing amounts of several types of powder obtained in the above operations. For example, the number frequency and its ratio were adjusted by mixing particles with known number frequencies in appropriate proportions, the specific surface area was adjusted by adding ultrafine powders with various particle sizes and specific surface areas, and the circularity was controlled by adjusting the flame formation conditions and the raw material supply amount.

[0055] Table 1 shows the physical properties of the spherical alumina particles used.

[0056] [Table 1]

[0057] Method for manufacturing slurry composition (Example 1) A slurry was prepared by dispersing 70 parts by mass of spherical alumina particles A obtained in the above process, 0.7 parts by mass of hexamethyldisilazane (HMDS) as a surface treatment agent, and 30 parts by mass of methyl ethyl ketone (MEK) as a dispersion medium in a disperser. (Example 2) The slurry was prepared using the same method as in Example 2, except that a surface treatment agent was not added. (Example 3) A slurry was prepared using the same method as in Example 2, except that ethanol was used as the dispersion medium. (Comparative Example 1) A slurry was prepared using the same method as in Example 1, except that spherical alumina particles B were used as the filler. (Comparative Example 2) The slurry was prepared using the same method as in Comparative Example 1, except that a surface treatment agent was not added. (Comparative Example 3) The slurry was prepared using the same method as in Comparative Example 2, except that ethanol was used as the dispersion medium.

[0058] [Table 2]

[0059] The measurement methods for each physical property are described below.

[0060] (Measured using the Coulter counter method) Spherical alumina particles and 150 mL of electrolyte were placed in a 200 mL glass beaker and dispersed for 30 seconds using an ultrasonic homogenizer (SMT, ULTRA SONIC HOMOGENIZER UH-300). This dispersion was then added to electrolyte prepared in another beaker to adjust the concentration. The individual particle sizes of the spherical alumina particles between 1 μm and 30 μm were measured using a Coulter counter (Beckman Coulter, Multisizer 4) with a 50 μm aperture. Approximately 100,000 particles were measured per measurement, and the same sample was measured three times. The number of particles with particle sizes of 5 μm and 10 μm or larger was calculated and expressed as the coarse particle frequency (ppm) relative to the total number of particles measured.

[0061] (D50 by laser diffraction scattering method) The particle size distribution was measured using a "Mastersizer3000" (manufactured by Malvern). For the measurement, a refractive index of 1.33 was used for the solvent, water, while the refractive index of the powder material was considered. For example, alumina was measured with a refractive index of 1.78.

[0062] (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 the "Maxsorb Model HM-1208" manufactured by Mountec Co., Ltd.

[0063] (Circularity) Circularity can be measured using an electron microscope or optical microscope and an image analysis device, such as the FPIA manufactured by Sysmex Corporation. 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 is measured for 100 or more particles, and the average value is taken as the circularity of the powder.

[0064] (Fluidity (Narrow area fluidity)) Using a narrow-section fluidity measurement mold with a groove width of 1 cm and a groove depth of 5 μm, as shown in Figure 1, the length over which a slurry composition containing spherical alumina particles flowed into the slit was measured. A longer length indicates better fluidity into the narrow section. A large length (2.5 cm or more) was marked with ○ (Excellent), a length between 1.5 cm and 2.5 cm was marked with △ (Good), and a small length (less than 1.5 cm) was marked with × (Not Good).

[0065] (permeability) A 0.09 mm thick, 8 cm square glass cloth was impregnated in 5 mL of slurry for 30 seconds, then removed and dried at 180°C for 1 hour. A larger increase in the weight of the glass cloth after drying indicates that it contains a larger amount of filler and has better permeability. A weight change of 0.30 g or more was evaluated as ○, 0.20 g or more but less than 0.30 g as △, and less than 0.20 g as ×.

[0066] The fluidity (fluidity in confined spaces) and permeability of the spherical alumina particle slurry compositions of Examples 1-3 and Comparative Examples 1-3 were measured as described above. The measurement results are shown in Table 2. It was confirmed that good fluidity, rated ○ (Excellent) or △ (Good), can be obtained in slurry compositions within the scope of the present invention. [Industrial applicability]

[0067] The spherical alumina particle slurry composition and the resin composite composition containing the same of the present invention exhibit good fluidity and are not limited to semiconductor encapsulating materials, but can be used for other applications as well. Specifically, they can be used as prepregs for printed circuit boards, various engineering plastics, and the like.

Claims

1. A slurry composition comprising spherical alumina particles and a dispersion medium, wherein, among the spherical alumina particles detected by a Coulter counter, the number frequency of particles 5 μm or larger is 300 ppm to 20,000 ppm, the number frequency of particles 10 μm or larger is 50 ppm or less, and the specific surface area measured by the BET method is 2.0 m². ２ / g or more 10.0m ２ A slurry composition characterized by having a concentration of less than or equal to / g.

2. The slurry composition according to claim 1, wherein the spherical alumina particles are surface-treated with a silane coupling agent.

3. The slurry composition according to claim 1, wherein the spherical alumina particles have a D50 of 0.4 μm or more and 3.0 μm or less as determined by laser diffraction scattering.

4. The slurry composition according to claim 1, wherein the circularity of the spherical alumina particles is 0.85 or greater.

5. The slurry composition according to claim 1, wherein, of the spherical alumina particles, among the particles of 1 μm to 30 μm detected by a Coulter counter, the number of particles of 20 μm or larger is less than 10 ppm.

6. The slurry composition according to claim 1, wherein a glass cloth measuring 0.09 mm in thickness and 8 cm in square is impregnated in 5 mL of the slurry composition for 30 seconds, and then removed and dried at 180°C for 1 hour, the weight increase of the glass cloth is 0.2 g or more.

7. The slurry composition according to claim 1, further comprising at least one inorganic filler selected from 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 fiber.

8. The slurry composition according to claim 1, wherein the relative permittivity of the dispersion medium is 5 to 30.

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