Spherical inorganic composition, resin composition, slurry composition, filler for encapsulant for semiconductor package, and method for analyzing void in spherical inorganic composition

Abstract

To provide a spherical inorganic composition suitable for use as a filler for encapsulants for semiconductor packages by accurately grasping the properties of voids present in particles of a spherical inorganic composition and improving the quality of the particles of the spherical inorganic composition.SOLUTION: In a spherical inorganic composition excluding silica alone, the average particle diameter by laser diffraction particle size distribution measurement of the spherical inorganic composition is 0.1 to 15 μm, particles of the spherical inorganic composition containing voids having a diameter of 5 μm or more are 50 particles / mm3 or less, and particles of the spherical inorganic composition containing voids having a diameter of 10 μm or more are 5 particles / mm3 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a spherical inorganic composition, a resin composition, a slurry composition, a filler for sealing materials for semiconductor packages, and a method for analyzing voids in spherical inorganic compositions, and in particular to a spherical inorganic composition having voids inside, other than simple silica, and a composition containing the same. [Background technology]

[0002] Encapsulant is used to protect semiconductor IC chips from dust, dirt, and moisture in the air, and the IC chip is then encapsulated to create a semiconductor package. The encapsulant is primarily a resin composition made up of a resin with high heat and chemical resistance and silica with a low thermal expansion coefficient. There are several methods for manufacturing semiconductor packages depending on the application and performance requirements. FOWLP (Fan-Out Wafer Level Package) and FOPLP (Fan-Out Panel Level Package) are used for packages that require high functionality and small size and are installed in mobile devices.

[0003] Various FOWLP processes include a polishing process to smooth the surface of the semiconductor package, including the encapsulant, after encapsulating the IC chip. If hollow particles are present in the encapsulant, or if air bubbles or other contaminants create cavities in the encapsulant, dents form on the polished package surface, reducing surface smoothness and appearance, resulting in lower yields. Particularly in processes where a redistribution layer is formed on the polished surface of a semiconductor package, the presence of hollow particles in the encapsulant can result in copper wiring forming on the dents on the package surface. When the package expands and contracts due to temperature changes, the voids in the dents can cause the copper wiring to break and disconnect. Without voids, the copper wiring is surrounded by the encapsulant, preventing breakage even when it expands and contracts. Conventional copper wiring has a large line width of over 10 μm, making it highly rigid and resistant to breakage. However, as package functionality and miniaturization advance, the line width becomes less than 10 μm, resulting in a decrease in the rigidity of the copper wiring. For this reason, attention has been focused on reducing the hollow particle content in the encapsulant (see, for example, references 1 and 2).

[0004] Server packages differ in structure and manufacturing process from those described above. The package is mounted on an interposer or similar device using a flip-chip structure, and then the entire package is sealed. There are also manufacturing methods that involve two processes: underfilling the narrow gap under the chip and overmolding to protect the entire chip. There are also manufacturing methods that seal both the chip and the top of the chip at the same time. High fluidity is particularly important for bulk sealing. These types of packages also require a surface polishing process to smooth the surface of the package, and, as with the above, a low hollow particle content in the filler used for sealing is also highly required. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2022-117398 [Patent Document 2] Patent Publication No. 2021-161008 Summary of the Invention [Problem to be solved by the invention]

[0006] As semiconductor packages become smaller and wiring becomes finer to meet the above-mentioned required characteristics, it is necessary to precisely remove the solid coarse particles used in fillers, and the size of the coarse particles that need to be removed is also becoming smaller.In addition, it is required to reduce the voids present inside the filler particles as much as possible, and therefore measuring the voids present inside filler particles is important from the perspective of quality control.

[0007] However, in conventional particle void measurement, the cross section of the particle is exposed by embedding it in resin or the like and grinding it. Therefore, the solid part of the particle and the void within it are measured. However, depending on the grinding position, the center of the void varies, and it is not necessarily the center of the filler, resulting in misalignment between the two. Even if the filler particle is cut to expose its cross section, the exact diameter of the void sphere is not exposed. The size and volume of the void are calculated from the cross-sectional diameter at a position away from the center, resulting in large errors. Furthermore, factors such as deformation or clogging of the void due to loads during grinding can cause errors. In particular, the larger the volume of the void, the more likely it is that a defect will occur due to a recess during the formation of the redistribution layer. This is because the resin components of the redistribution layer flow into the recess, causing localized loss of flatness.

[0008] The present invention has been made in consideration of the above points, and aims to accurately grasp the properties of the voids present in particles of spherical inorganic compositions other than silica alone, thereby improving the quality of the particles of the spherical inorganic compositions, and to provide spherical inorganic compositions suitable for resin compositions, slurry compositions, and fillers for sealing materials for semiconductor packages, and also to provide a method for analyzing the voids in spherical inorganic compositions other than silica alone. [Means for solving the problem]

[0009] That is, the spherical inorganic composition other than silica alone in the embodiment has an average particle size of 0.1 to 15 μm as measured by laser diffraction particle size distribution, and the particles of the spherical inorganic composition containing voids with a diameter of 5 μm or more are present at a density of 50 particles / mm 3 and the spherical particles of the inorganic composition containing voids of 10 μm or more in diameter are 5 particles / mm 3 The present invention is characterized by the following:

[0010] Furthermore, in the spherical inorganic composition, when the spherical inorganic composition is filled into a resin material having a solid content concentration of 70 mass %, a 150 μm particle size detected by a cross-sectional analysis of the resin composition is 3 The spherical inorganic composition particles containing the above voids are 14 particles / mm 3 35 μm or less, which is detected by tomographic cross-section analysis 3 The particles of the spherical inorganic composition containing voids are 50 particles / mm 3 It may be the following.

[0011] Furthermore, in the spherical inorganic composition, the cross-sectional analysis may be performed by X-ray CT or FIB-SEM.

[0012] Furthermore, the spherical inorganic composition may be made of alumina, calcium titanate, or a silica-alumina composite oxide.

[0013] Furthermore, the content of uranium element in the spherical inorganic composition may be 100 ppb or less.

[0014] Furthermore, the spherical inorganic composition may be surface-treated with a silane compound.

[0015] Furthermore, the resin composition of the embodiment may include a spherical inorganic composition other than simple silica, and a resin material that disperses the spherical inorganic composition.

[0016] Furthermore, the slurry composition of the embodiment may contain a spherical inorganic composition other than simple silica, and a dispersion medium for dispersing the spherical inorganic composition.

[0017] Furthermore, the filler for a semiconductor package sealant according to the embodiment may contain a spherical inorganic composition other than simple silica.

[0018] The embodiment of the method for analyzing voids in a spherical inorganic composition is characterized by comprising a dispersion step in which the spherical inorganic composition excluding simple silica is dispersed in a resin composition, a cross-sectional analysis step in which the spherical inorganic composition together with the resin composition is subjected to cross-sectional analysis using X-ray CT or FIB-SEM, and a void calculation step in which a three-dimensional image is prepared from the cross-sectional analysis and the diameter and volume of voids present within the spherical inorganic composition are calculated.

[0019] Furthermore, the method for analyzing voids in a spherical inorganic composition may include a curing step of curing the resin composition after the dispersion step. [Effects of the Invention]

[0020] The present invention provides a spherical inorganic composition containing inorganic raw materials other than simple silica as a main component, the spherical inorganic composition having an average particle size of 0.1 to 15 μm as measured by laser diffraction particle size distribution measurement, and containing voids with a diameter of 5 μm or more at a rate of 50 particles / mm 3 and the spherical particles of the inorganic composition containing voids of 10 μm or more in diameter are 5 particles / mm 3 The characteristics of the voids present in spherical inorganic particles other than simple silica can be accurately grasped, thereby improving the quality of the spherical inorganic particles. Furthermore, by applying the method for analyzing the voids in spherical inorganic compositions, the accuracy of measuring the voids present in the spherical inorganic compositions can be improved. DETAILED DESCRIPTION OF THE INVENTION

[0021] The spherical inorganic composition, resin composition, slurry composition, filler for semiconductor package encapsulant, and method for analyzing voids in the spherical inorganic composition according to the embodiment are described below. The spherical inorganic particles according to the embodiment (excluding silica alone) can be dispersed in a resin material to form a resin composition, or dispersed in a liquid dispersion medium to form a slurry composition. They are particularly suitable for use as fillers for semiconductor package encapsulants, antenna-in-packages, etc.

[0022] (Spherical inorganic composition and filler for semiconductor package encapsulant) The spherical inorganic composition of the embodiment (excluding silica alone) is in the form of particles, and the particles are suitably used as a filler for semiconductor package encapsulants. As semiconductors, it is preferable to apply it to those produced using FOWLP and FOPLP techniques.

[0023] The spherical inorganic composition of the embodiment is formed from inorganic components other than particles of simple silica, specifically alumina, calcium titanate, silica-alumina composite oxide, etc., and further contains metal oxides such as magnesia, zirconia, titania, etc. The properties required for the spherical inorganic composition of alumina, calcium titanate, and silica-alumina composite oxide are as follows. ·alumina In the case of alumina, when the encapsulant is polished during WLP and a redistribution layer is formed on top of it, the internal voids of the particles filled in the encapsulant are exposed by the polishing, and the resin of the redistribution layer flows into the voids. This reduces the flatness of the redistribution layer and makes it more likely for poor conductivity to occur. The content of particles that increase the internal void volume is important for encapsulants for WLP. However, it is difficult to accurately grasp the internal voids of particles using cross-sectional observation in conventional technology. In contrast, the embodiment makes it possible to accurately grasp the voids within alumina particles, thereby improving particle precision. Calcium titanate When calcium titanate is added as a filler to increase the dielectric constant, the inclusion of calcium titanate particles with a high hollowness causes a decrease in the dielectric constant. In particular, when calcium titanate particles are filled into a substrate for high-frequency communications, the inclusion of calcium titanate particles with a high hollowness causes a local decrease in the dielectric constant, leading to an increase in transmission loss. In this regard, the embodiment makes it possible to accurately grasp the voids in the calcium titanate particles, which can contribute to improving quality. Silica-alumina composite oxide In the case of silica-alumina composite oxides, the refractive index of the filler itself can be matched to that of the matrix resin material, such as in photosensitive films, lenses, and adhesives used in photoelectric integration, with the aim of improving the strength of the resin material while still transmitting light. When adding fillers in this way, the inclusion of highly hollow silica-alumina composite oxide particles can cause haze. In this regard, the present embodiment makes it possible to accurately determine the voids in the silica-alumina composite oxide, thereby mitigating the refractive index problem.

[0024] For spherical inorganic compositions, the inorganic composition components account for 50% or more of the mass of the composition, preferably 60% or more, 70% or more, 80% or more, 90% or more, or 95% or more. In the spherical inorganic composition of the embodiment, silica may be present in the components due to unavoidable contamination during manufacturing. In other words, silica is actively excluded from the raw materials, and unavoidable contamination with silica components is eliminated. However, silica-alumina composite oxides are distinguished from silica (SiO2) because they have a crystalline structure composed of silicon, aluminum, and oxygen.

[0025] Compounds that may be contained in calcium titanate include titanium oxide, iron oxide, molybdenum oxide, silicon dioxide, etc. Impurities may be contained in the calcium titanate crystals or as independent particles.

[0026] Among spherical inorganic compositions, alumina is known to have α, γ, or θ crystal structures, while calcium titanate is known to have a perovskite structure. The proportion of crystalline components in spherical inorganic compositions varies depending on the type.

[0027] The material for the spherical inorganic composition of silica-alumina composite oxide is composed of an oxide (including composite oxide) containing silicon and aluminum, and has a crystallinity of 0.5% or less. The silicon and aluminum composition ratio is preferably less than 50% by mass of aluminum based on the mass of silicon and aluminum, with upper limits of 35%, 30%, 27.5%, 25%, or 20% being more preferred. Furthermore, based on the number of moles of silicon, the number of moles of aluminum is preferably 10% or more, more preferably 15% or more, and even more preferably 20% or more.

[0028] For each type of spherical inorganic composition, the D measured by laser diffraction particle size distribution measurement 50 (Median diameter) is 0.1 μm or more and 15 μm or less. D 50 Examples of the lower limit are 0.2 μm, 0.5 μm, 1.0 μm, and 1.3 μm, and examples of the upper limit are 14.0 μm, 11.0 μm, 9.0 μm, 8.0 μm, 7.0 μm, and 6.0 μm. These upper and lower limit values ​​can be combined in any way.

[0029] D 50 is a value measured by laser diffraction particle size distribution measurement, and is the particle size that makes up 50% of the smallest particle size on a volume basis. 100 is the particle size of 100% from the smallest particle size. 50 , D 100 The value of D is calculated as a numerical value within the range of the measurement limit of laser diffraction particle size distribution measurement, and in reality, there are coarse particles and fine particles that cannot be detected by laser diffraction particle size distribution measurement. 100 There is no contradiction in the existence of particles with a particle size larger than the value of

[0030] D50 The value of is controlled by the manufacturing conditions of the spherical inorganic composition. In addition, it is adjusted by a classification operation and the addition of particulate materials with other particle size distributions. For the classification operation, centrifugal separation such as a cyclone is preferably used. The added particulate materials are also subjected to a classification operation.

[0031] For spherical inorganic compounds, when the solid content is 80% by mass and the compound is filled into a resin material, the viscosity of the compound is 1500 Pa·s or less (at a shear rate of 1 s -1 ), preferably 100 Pa·s or less, and more preferably 500 Pa·s or less. As the resin material, an epoxy resin obtained by mixing bisphenol A type epoxy resin and bisphenol F type epoxy resin in a 1:1 ratio is used (for example, ZX-1059 manufactured by Nippon Steel Chemical Materials Co., Ltd.).

[0032] The specific surface area of ​​the spherical inorganic composition is 0.1 m 2 / g or more, 15m 2 / g or less. The lower limit of the specific surface area is 0.2 m 2 / g, 0.5m 2 / g, 0.8m 2 / g is exemplified, with an upper limit of 10m 2 / g, 7m 2 / g, 5m 2 / g is an example of the specific surface area. The specific surface area is a value measured by the BET method using nitrogen. A smaller specific surface area is preferable because it reduces the viscosity when used in a slurry composition or the like. The method for controlling the specific surface area is not particularly limited, and the specific surface area can be adjusted by performing the synthesis of the spherical inorganic composition under conditions that reduce the amount of fine powder, or by controlling the residence time in a classifier to be longer during classification, thereby reducing the amount of fine powder.

[0033] The voids contained in the spherical inorganic composition refer to hollow particles, which are bubbles that occur during the manufacturing process of the spherical inorganic composition. Obviously, the fewer voids (hollow particles) there are, the better. However, voids inevitably occur during the manufacturing process of spherical inorganic compositions such as the aforementioned alumina, calcium titanate, or silica-alumina composite oxides.

[0034] Regarding voids (hollow particles), the spherical inorganic composition is added to a resin material so that the solid content is 70% by mass, and the standard is 150 μm. 3 The spherical inorganic composition particles having the above voids are 14 particles / mm 3 Below, 10 pieces / mm 3 Below, 5 pieces / mm 3 or less, and most preferably 0 pieces / mm 3 In total, 35 μm 3 The spherical inorganic composition particles having the above voids are 50 particles / mm 3 Below, 30 pieces / mm 3 Below, 15 pieces / mm 3 or less, and most preferably 10 pieces / mm 3 The following is the result.

[0035] Furthermore, based on the case where the spherical inorganic composition is filled into a resin material so that the solid content concentration after addition is 70 mass %, the number of particles of the spherical inorganic composition having voids with a diameter of 5 μm or more is 50 / mm 3 Below, 30 pieces / mm 3 Below, 10 pieces / mm 3 or less, and most preferably 10 pieces / mm 3 In addition, the number of spherical inorganic composition particles having voids of 10 μm or more in diameter is 10 particles / mm 3 Below, 5 pieces / mm 3 or less, and most preferably 3 particles / mm 3 The following is the result.

[0036] The size of the voids (hollow particles) contained in each spherical inorganic composition has been evaluated by their diameter. To measure the diameter of the voids (hollow particles), the spherical inorganic composition is embedded in a resin or the like, and then the resin block is cut to measure the diameter of the voids (hollow particles) from the cut surface of the spherical inorganic composition exposed on the cross section. However, when cutting the resin block, the spherical inorganic composition is dispersed in the resin, so the position of the spherical inorganic composition that becomes the cut surface is completely random. For example, if the cut surface is located away from the center of the spherical inorganic composition, the voids exposed on the cut surface of the spherical inorganic composition are measured as having an apparently small diameter. It is impossible for all of the spherical inorganic composition to be cut exactly at the center of the sphere. Therefore, measuring the size of the voids (hollow particles) based on the cutting position lacks precision.

[0037] Therefore, if the size of the voids (hollow particles) is to be precisely measured, it is necessary to grasp the void diameters in multiple cross-sectional portions of the spherical inorganic composition. In light of this, in this embodiment, cross-sectional analysis is performed. Specifically, X-ray CT or FIB-SEM is used for the analysis. When using X-ray CT, cross-sectional images of the resin mass in which the spherical inorganic composition is dispersed (embedded) are captured. It is desirable that the capture interval (pitch) between the cross-sectional images be a fine range, such as 1 μm or less. From each cross-sectional image, the diameter of the voids (hollow particles) present within each individual spherical inorganic composition can be measured more precisely. The volume of the voids (hollow particles) is then calculated. Even if the shape of the voids is not spherical but distorted, the volume of distorted voids can also be calculated from image analysis of the combined cross-sectional images.

[0038] When using FIB-SEM, a focused ion beam is irradiated and scanned onto a resin mass in which spherical inorganic compositions are dispersed (embedded), gradually grinding the surface down to a fine area of ​​1 μm or less. This gradually exposes the voids (hollow particles) present within each spherical inorganic composition. The diameter of each void within each spherical inorganic composition is then measured according to the amount (depth) of grinding caused by ion beam irradiation. Using FIB-SEM, the volume of the voids (hollow particles) can also be calculated, and measurements of irregularly shaped voids are also possible.

[0039] The aforementioned number of measurements is calculated from analysis using X-ray CT or FIB-SEM. The measurement conditions for X-ray CT or FIB-SEM are to cut in at a pitch of 1 μm or less and observe the void diameter with the largest diameter, or to construct three-dimensional data, and calculate the void diameter and void volume within the particle from the difference in contrast (brightness and darkness) between the surrounding resin, the spherical inorganic composition, and the voids. Alternatively, X-ray CT data is obtained under conditions of a voxel size of 2 μm or less, and the void diameter and void volume within the particle are calculated from the contrast difference. When analyzing using X-ray CT or FIB-SEM, the analysis range is 0.5 mm 3 That's all.

[0040] An essential point of view is to accurately measure the number of hollow particles with large void volumes. In fact, the void volume (volume) measured using X-ray CT or the like as in the embodiment deviates from the theoretical sphere volume calculated from the void diameter. This is because the void shape within the particle is often not a perfect sphere. By performing the cross-sectional analysis of the embodiment, the diameter and volume of the voids (hollow particles) for each spherical inorganic composition can be accurately detected and calculated. This improves the accuracy of quality control of the finished spherical inorganic composition. In particular, this contributes greatly to improving the yield when processing wiring with narrower line widths.

[0041] (Method for analyzing voids in spherical inorganic compositions) The method for analyzing the voids in spherical inorganic compositions can be summarized as follows: First, the spherical inorganic composition is dispersed (embedded) in a resin composition. The resin is of the composition described above. The solids concentration of the spherical inorganic composition in the resin composition is adjusted to 60 to 80% by mass, preferably 70% by mass (dispersion process). The purpose of the dispersion process in the resin is to fix the position of each particle of the spherical inorganic composition for subsequent measurement analysis. Furthermore, after the dispersion process, a curing process is added to harden the resin composition. In this curing process, the resin composition is heated and irradiated with ultraviolet light, and the resin composition is prepared into a cured resin. Obviously, a thermosetting resin or an ultraviolet-curable resin is selected for the resin composition.

[0042] The spherical inorganic composition together with the resin composition is subjected to cross-sectional analysis using X-ray CT or FIB-SEM (cross-sectional analysis process). The method of cross-sectional analysis is as described above. A three-dimensional image is prepared from the cross-sectional analysis, and the diameter and volume of voids present within the spherical inorganic composition are calculated (void calculation process). The cross-sectional analysis process and void calculation process can be performed in a consistent manner, and the analysis range, voxel size, etc. are appropriately adjusted to calculate the maximum diameter and volume of voids (hollow particles) present within each spherical inorganic composition.

[0043] The spherical inorganic composition of the embodiment is preferably surface-treated with a surface treatment agent such as a silane compound or a silazane compound. The silane compound or silazane compound is not particularly limited, and a silane compound or silazane compound having an appropriate functional group is selected as needed for the surface treatment. The surface treatment is performed using a combination of two or more silane compounds and silazane compounds.

[0044] For the surface treatment, it is preferable to use a surface treatment agent capable of introducing functional groups such as trimethylsilyl, isocyanate, amino, phenyl, phenylamino, vinyl, methacryl, and epoxy groups. For example, a titanate coupling agent, an aluminate coupling agent, or a silane compound having the functional group to be introduced can be reacted.

[0045] Examples of aluminate coupling agents include acetoalkoxyaluminum diisopropylate, aluminum alkylacetoacetate diisopropylate, aluminum ethylacetoacetate diisopropylate, aluminum trisethylacetoacetate, aluminum isopropylate, aluminum diisopropylate mono-secondary butylate, aluminum secondary butylate, aluminum ethylate, aluminum bisethylacetoacetate monoacetylacetonate, aluminum trisacetylacetonate, and aluminum monoisopropoxymonoroxyethylacetoacetate.

[0046] The surface treatment agent may be a single compound or a mixture of multiple compounds. The organic functional group is determined depending on the type of resin material and dispersion medium to be combined. The amount of the surface treatment agent is not particularly limited, and the surface treatment amount is 0.1 to 5.0 parts by mass per 100 parts by mass of the spherical inorganic composition.

[0047] For the spherical inorganic composition of the embodiment, the amount of alpha rays produced is 0.001 c / cm 2 In particular, it is desirable that the amount of uranium as an α-ray source is 100 ppb or less, further 5 ppb or less, preferably 3 ppb or less, and more preferably 1 ppb or less.

[0048] (Metal Oxide Particle Material Manufacturing Method) In producing the spherical inorganic composition of the embodiment, a typical method for producing each component will be presented, and the method includes a production step, a classification step, and other steps that may be adopted as necessary.

[0049] Manufacturing process (spherical inorganic alumina composition) Various crystalline aluminas (aluminum oxides) are used as raw particle materials, and particle materials with an average particle size larger than the average particle size (volume average particle size) of the spherical inorganic composition to be finally prepared are used as the raw particle material. Then, a raw particle material with the required volume average particle size can be obtained by a pulverization operation. For example, the particle size distribution is adjusted after pulverizing the raw particle material. Alternatively, or in addition to adjusting the particle size distribution after pulverization, the particle size distribution can be adjusted before pulverization. To control the particle size distribution, it is preferable to remove particles with small particle sizes.

[0050] The raw material particles are preferably produced by the VMC method (deflagration process). The VMC method, also known as the "Vaporized Metal Combustion Method," is a method for producing spherical oxide microparticles by utilizing the deflagration phenomenon of metal powder. The spherical inorganic alumina composition produced by the VMC method has high sphericity, is dense, and has excellent electrical properties. Metallic aluminum is used as the raw material particle material. The VMC method involves burning a combustible (such as hydrocarbon gas) with a burner in an oxygen-containing atmosphere to form a high-temperature chemical flame, and then introducing an amount of raw material particles into this chemical flame that is sufficient to form a dust cloud, causing deflagration to occur, thereby obtaining particulate oxides. The high-temperature atmosphere is preferably an atmosphere of 2000°C or higher.

[0051] The VMC process works as follows: First, a vessel is filled with a gas containing oxygen, a reactive gas, and a chemical flame is formed within this reactive gas. Next, the raw material particles are introduced into this chemical flame, forming a dust cloud. The chemical flame then imparts thermal energy to the surface of the raw material particles, raising the surface temperature of the metals that make up the raw material particles. This vaporizes the metals from the surface of the raw material particles and spreads to the surrounding area. This vapor reacts with oxygen gas, igniting and generating a flame. The heat generated by this flame further promotes the vaporization of the raw material particles, and the resulting vapor mixes with oxygen gas, causing a chain reaction of ignition and propagation. Therefore, the smaller the particle size of the raw material particles, the larger the specific surface area and the greater the reactivity, thereby reducing the amount of energy input.

[0052] When alumina is produced by the VMC process, a mixture of large and small particle size material is obtained, and the large particle size fraction is therefore classified and used as the raw material particle size.

[0053] The grinding method is not particularly limited, and common grinding methods such as jet mills, ball mills, and vibrating ball mills can be used. Jet mills are particularly preferred because they minimize the inclusion of impurities from the grinding media and also provide high grinding efficiency on the micrometer order. Particle materials produced by the VMC method have a high degree of circularity and may contain a certain amount of fine particles with a particle size distribution of less than 1 μm.

[0054] The particulate material made of metal oxide produced by the VMC method is used as it is or after classification as a crude raw material particulate material. Because the metals that make up the metallic particulate material used as the raw material for the VMC method are easier to purify than the metal oxides, it is easy to increase the purity of the raw material particulate material obtained through the VMC method.

[0055] In addition to the preparation of spherical inorganic compositions of alumina by the VMC method described above, spherical inorganic compositions of alumina can also be prepared by a flame fusion method or the like. In the preparation of spherical inorganic compositions of alumina by the flame fusion method, the raw material alumina is pulverized to, for example, 5 μm or less, and granulation or the like is carried out according to the target particle size. Alternatively, heating is carried out, for example, at a temperature exceeding 1000°C, which promotes the dissociation of moisture contained in the crystals and gasification of the moisture, making it easier to reduce voids.

[0056] By utilizing the principle of dust explosion in the VMC method, a large amount of spherical inorganic alumina composition can be obtained instantaneously. The resulting spherical inorganic alumina composition has a nearly perfect spherical shape. By adjusting the particle size, amount, and flame temperature of the raw material particles added, it is possible to adjust the particle size distribution of the resulting spherical inorganic alumina composition. Furthermore, the raw material particles can be surface-treated with a silane compound, a silazane compound, or the like. There are no particular limitations on the type of silane compound that can be used, and the types of surface treatment compounds described above can be used.

[0057] The raw material particles are dispersed in a carrier and then fed into the flame to be combusted. The speed at which the raw material particles are fed into the flame is not particularly limited. The carrier may be a gas such as nitrogen, argon, or air, or a liquid such as water or alcohol. There are no particular limitations on how the particles are dispersed; when dispersed in a liquid, it is preferable to spray the particles into the flame in a mist form. For example, it is preferable to have the raw material particles contained in an amount of about 10% to 80% by volume of the total.

[0058] The flame used is a flame in an oxidizing atmosphere. For example, a flame in which flammable gases such as LPG, ammonia, and hydrogen are burned in an atmosphere containing excess oxygen is used. Thermal plasma is also included in the flame. The raw material particles introduced into the flame are vaporized by combustion and rapidly cooled to become raw alumina particles made of alumina. The resulting raw alumina particles are collected using a bag filter or the like.

[0059] Manufacturing process (spherical inorganic composition of calcium titanate) In the production of the spherical inorganic composition of calcium titanate according to the embodiment, calcium titanate is used as the raw material particle material, and a particle material having a larger average particle size (volume average particle size) than the average particle size (volume average particle size) of the spherical inorganic composition to be finally prepared is used as the raw material particle material. Then, a raw material particle material having the required volume average particle size is produced by a grinding operation. For example, the particle size distribution is adjusted after grinding the raw material particle material. Alternatively, or in addition to adjusting the particle size distribution after grinding, the particle size distribution can be adjusted before grinding. To control the particle size distribution, it is preferable to remove particles with small particle sizes.

[0060] In the production of spherical inorganic compositions of calcium titanate, raw material particles are heated and melted in a high-temperature atmosphere to form spheroids, followed by rapid cooling to obtain highly circular particles. The high-temperature atmosphere is at a temperature above the temperature at which calcium titanate can be softened or melted. The high-temperature atmosphere may be a flame or plasma formed by burning a combustible gas mixed with a combustion-assistant gas. Examples of combustible gases include propane gas, acetylene gas, and hydrogen gas. Furthermore, the raw material particles are introduced into the high-temperature atmosphere in the form of a dispersion dispersed in a carrier. Examples of carriers include inert gases such as nitrogen, combustion-assistant gases such as oxygen, combustible gases such as propane, water, alcohols such as methanol and isopropanol, and ketones such as acetone.

[0061] In the production of the spherical inorganic composition of calcium titanate, the surface may be treated with a silane compound or a silazane compound to introduce an alkyl group such as a phenyl group or a methyl group.

[0062] Manufacturing process (spherical inorganic composition of silica-alumina composite oxide) When producing a spherical inorganic composition of silica-alumina composite oxide, the raw particle material is a particle material containing metallic silicon and metallic aluminum. The metallic silicon and metallic aluminum may be a mixture of separate particle materials, or a particle material consisting of an alloy of metallic silicon and metallic aluminum. Since the purity of the raw particle material directly affects the purity of the spherical inorganic composition, the purity of the raw particle material is adjusted to the required purity.

[0063] Metallic silicon and metallic aluminum are made into a particulate material by dissolving them in a chemical solution and pulverizing them using an atomizer or the like. The abundance ratio of metallic silicon and metallic aluminum contained in the raw particle material is roughly the same as the abundance ratio of silicon and aluminum contained in the spherical composite oxide particle material to be produced. The average particle size of the raw particle material is not particularly limited and is about 0.1 μm to 40 μm.

[0064] Furthermore, the raw material particles are subjected to a surface treatment. By performing the surface treatment, aggregation of the raw material particles is suppressed when the particles are introduced into a high-temperature oxidizing atmosphere (described later). Examples of the surface treatment include organic silicon compounds such as silane compounds, organic aluminum compounds such as aluminate coupling agents, and organic titanium compounds such as titanate coupling agents.

[0065] The VMC method is also used to produce spherical inorganic silica-alumina composite oxides, just like the alumina mentioned above. As a result, the raw material particles are converted into oxides through a deflagration reaction, and the resulting oxides fall due to gravity and other factors. Once removed from the high-temperature oxidizing atmosphere, they are rapidly cooled and become spherical, producing spherical inorganic silica-alumina composite oxides. The resulting composition is then recovered using a bag filter or cyclone.

[0066] Spherical inorganic compositions of silica-alumina composite oxides are surface-treated with surface treatment agents such as organosilicon compounds (silane compounds), organoaluminum compounds, or organotitanium compounds. In surface treatment, the surface treatment agent is either directly contacted with the surface of the composition (either in liquid or gaseous form), or is dissolved in a solvent and then contacted with the surface of the composition. Heating after surface treatment can sometimes promote a reaction between the surface treatment agent and the surface of the spherical inorganic compositions of silica-alumina composite oxides.

[0067] ·Classification process The classification step is a step of classifying the spherical inorganic composition prepared from each raw material until the content of coarse particles is below the upper limit mentioned above and the content of hollow particles with a particle size of 5 μm or more is below the upper limit mentioned above. The coarse particles consist of solid particles and hollow particles. Classification procedures include centrifugation in a gas or solvent, separation by specific gravity in a liquid, and dry or wet sieving. Classification is repeated until the desired particle size distribution is achieved.

[0068] Centrifugation is a method suitable for removing solid particles from among coarse particles. It is desirable that the solvent used for centrifugation has low viscosity. Examples include methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and toluene. Solid coarse particles can be separated with high precision by performing centrifugation while the particles are dispersed in MEK at a concentration of about 10% by mass to 30% by mass (particularly 15% by mass to 25% by mass). Wet centrifugation can separate coarse particles by applying centrifugal force to the slurry, causing the coarse particles to settle and be removed.

[0069] To separate coarse particles consisting of hollow particles, it is preferable to separate hollow particles with a low specific gravity after dispersion in a liquid. Separation in a liquid is preferably performed by removing the hollow particles present in the supernatant after leaving the dispersion to stand or applying centrifugal force (hollow particle separation process). The liquid used is the same type as the liquid used in centrifugation. Furthermore, among the coarse particles, solid particles settle quickly, while hollow particles settle slowly or not at all. Therefore, by removing the supernatant in addition to the operation for removing the coarse particles described above, it is possible to simultaneously remove coarse particles consisting of solid particles and coarse particles consisting of hollow particles. Furthermore, when classification using a filter is performed, it is performed in the form of a dispersion slurry dispersed in a solvent. It is desirable to perform the classification operation using a filter multiple times. If performing the classification operation multiple times, it is preferable to perform the classification operation using a filter while switching from a filter with a large pore size to a filter with a small pore size.

[0070] Other processes The above-mentioned surface treatments correspond to the other steps. Surface treatments can be selectively combined. The surface treatment can be performed before, after, or during the classification step on the spherical inorganic composition prepared from the raw materials produced in the manufacturing process.

[0071] The amount of surface treatment agent used for surface treatment is not particularly limited. For example, when a substance that reacts with the surface of particles, such as a silane compound or a silazane compound, is used as the surface treatment agent, an amount that reacts with 100%, 75%, 50%, 25%, etc., based on the amount of OH groups present on the surface of the particles to be treated is selected. Furthermore, an excess amount exceeding 100% (120%, 150%, etc.) can also be selected. In this case, unreacted surface treatment agent remains on the surface of the particles. The silane compound is not particularly limited, and examples include compounds having a phenyl group, an alkyl group, a vinyl group, a methacryl group, an epoxy group, a phenylamino group, an amino group, a styryl group, etc.

[0072] (Resin composition) The resin composition of the embodiment is a composition obtained by dispersing a spherical inorganic composition prepared from the aforementioned raw materials (alumina, calcium titanate, silica-alumina composite oxide) in a resin material (including a resin material precursor). The mixing ratio of the spherical inorganic composition and the resin material is not particularly limited. The resin material may be any appropriate material, such as an epoxy resin, an acrylic resin, or a silicone resin. It may also be a resin material precursor before curing.

[0073] (Slurry Composition) The slurry composition of the embodiment is a composition obtained by mixing a spherical inorganic composition prepared from the aforementioned raw materials (alumina, calcium titanate, silica-alumina composite oxide) with a liquid dispersion medium (solvent, resin material precursor, etc.). The mixing ratio of the spherical inorganic composition to the dispersion medium is not particularly limited. In addition to the aforementioned resin material precursor, examples of the dispersion medium include MEK, MIBK, alcohols such as hexane and 2-propanol. [Example]

[0074] The spherical inorganic compositions of the embodiments, and the manufacturing method and analytical method thereof were prepared and carried out as follows: Test Examples 1 to 15 show the preparation of each test example.

[0075] (Test Example 1: Alumina) Using metallic aluminum with a uranium content of 5 ppb or less as the raw material, spherical alumina was produced using the VMC method described above. This was then pulverized in a jet mill to an average particle size of 3 μm, and placed in a melting furnace in a high-temperature atmosphere (approximately 2000°C) where it was rapidly cooled and spheroidized. The resulting spherical alumina was then wet classified to 5 μm in an aqueous solvent and dried. Alumina synthesized by the VMC method with an average particle size of 0.2 μm was blended to achieve a closest-packed design.

[0076] (Test Example 2: Alumina) Low-sodium crushed alumina with an average particle size of 3 μm was placed in a melting furnace and spheroidized. The resulting spherical alumina was then wet classified to 10 μm in an aqueous solvent and dried. Alumina synthesized by the VMC method with an average particle size of 0.2 μm was blended to achieve a closest-packed design.

[0077] (Test Example 3: Alumina) Using metallic aluminum with a uranium content of 5 ppb or less as the raw material, spherical alumina was produced using the VMC method described above. This was then pulverized in a jet mill to an average particle size of 4 μm, and placed in a melting furnace under a high-temperature atmosphere (approximately 2000°C) where it was rapidly cooled and spheroidized. The resulting spherical alumina was then wet classified in an aqueous solvent to a size of 10 μm and dried. Alumina synthesized by the VMC method with an average particle size of 0.2 μm was blended to achieve a closest-packed design.

[0078] (Test Example 4: Alumina) Using metallic aluminum with a uranium content of 20 ppb or less as the raw material, spherical alumina with an average particle size of 9.8 μm was produced using the VMC method described above, and then classified to 10 μm by wet classification in an aqueous solvent and dried.

[0079] (Test Example 5: Alumina) Using metallic aluminum with a uranium content of 5 ppb or less as the raw material, spherical alumina with an average particle size of 0.2 μm was produced using the VMC method described above, and then classified into 5 μm particles by wet classification in a water solvent and dried.

[0080] (Test Example 6: Alumina) Using metallic aluminum with a uranium content of 5 ppb or less as the raw material, spherical alumina was produced using the VMC method described above. This was then pulverized in a jet mill to an average particle size of 1.8 μm, and placed in a melting furnace under a high-temperature atmosphere (approximately 2000°C) where it was rapidly cooled and spheroidized. The resulting spherical alumina was then wet classified to 3 μm in an aqueous solvent and dried. Alumina synthesized by the VMC method with an average particle size of 0.2 μm was blended to achieve a closest-packed design.

[0081] (Test Example 7: Alumina) Using metallic aluminum with a uranium content of 5 ppb or less as the raw material, spherical alumina with an average particle size of 0.2 μm was produced using the VMC method described above, and then classified into 3 μm particles by wet classification in a water solvent and dried.

[0082] (Test Example 8: Calcium titanate) Crushed calcium titanate particles with an average particle size of 1.5 μm were introduced into a melting furnace with a flame of propane gas as the flammable gas and oxygen as the combustion support gas, along with a carrier gas consisting of air. The particles were sphericalized by surface tension during melting, then dropped away from the flame, cooled, and solidified. The resulting spherical calcium titanate was collected and then classified to 5 μm using air classification.

[0083] (Test Example 9: Calcium titanate) The spherical calcium titanate obtained from the melting furnace in Test Example 8 was classified to 5 μm by wet classification in a 2-propanol solvent.

[0084] (Test Example 10: Calcium titanate) In Test Example 8, the spherical calcium titanate obtained from the melting furnace was used as it was.

[0085] (Test Example 11: Silica-alumina composite oxide) Metallic silicon powder with an average particle size of 20 μm and a purity of 99% or higher was blended with metallic aluminum powder with an average particle size of 25 μm and a purity of 99% or higher in a mass ratio of Si:Al = 60:40 (raw material). Following the previously described VMC method, the raw material was introduced into a high-temperature, oxidizing flame in a melting furnace using propane gas as the flammable gas and air as the combustion support gas. Using the VMC method, the metallic material exploded and vaporized, forming droplets below its boiling point. It then solidified below its melting point to form spherical particles. The silica-alumina composite oxide resulting from solidification was recovered, subjected to wet gravity classification in an aqueous solvent to remove hollow particles, and then dried. Finally, a silica-alumina composite oxide with an average particle size of 0.2 μm was prepared.

[0086] (Test Example 12: Silica-alumina composite oxide) In Test Example 11, the spherical silica-alumina composite oxide obtained from the melting furnace was used as it was.

[0087] (Test Example 13: Silica-alumina composite oxide) Metallic silicon powder with an average particle size of 20 μm and a purity of 99% or higher was blended with metallic aluminum powder with an average particle size of 25 μm and a purity of 99% or higher in a mass ratio of Si:Al = 60:40 (raw material). Following the previously described VMC method, the raw material was introduced into a high-temperature, oxidizing flame in a melting furnace using propane gas as the flammable gas and air as the combustion support gas. Using the VMC method, the metallic material exploded and vaporized, forming droplets below its boiling point. It then solidified below its melting point to form spherical particles. The silica-alumina composite oxide resulting from solidification was recovered, subjected to wet gravity classification in an aqueous solvent to remove hollow particles, and then dried. Finally, a silica-alumina composite oxide with an average particle size of 0.5 μm was prepared.

[0088] (Test Example 14: Silica-alumina composite oxide) To 100 parts by mass of Aluminosol 10A (manufactured by Kawaken Fine Chemicals Co., Ltd.), 40 parts by mass of 2-propanol was added, and 10 parts by mass of tetraethyl orthosilicate was added. After reacting for 24 hours at room temperature, the mixture was neutralized with aqueous ammonia to obtain a gel-like precipitate. The precipitate was calcined at 1100°C, slowly cooled, washed with pure water, and dried at 160°C for 2 hours. After drying, the precipitate was pulverized using a jet mill to an average particle size of 2 μm or less. The pulverized material was then placed in a melting furnace and spheroidized.

[0089] (Test Example 15: Silica-alumina composite oxide) To 100 parts by mass of Aluminosol 10A (manufactured by Kawaken Fine Chemicals Co., Ltd.), 40 parts by mass of 2-propanol was added, and 10 parts by mass of tetraethyl orthosilicate was added. After reacting at room temperature for 24 hours, the mixture was neutralized with aqueous ammonia to obtain a gel-like precipitate. The precipitate was washed with pure water and dried at 160°C for 2 hours. After drying, the precipitate was pulverized using a jet mill to an average particle size of 2 μm or less. The pulverized material was then placed in a melting furnace and spheroidized.

[0090] (Test Example 16: Glass) Glass frit with an average particle size of 21 μm was crushed to an average particle size of 2.3 μm, and then charged into a melting furnace to be spheroidized.

[0091] (Particle size distribution measurement) For each test example, the particle size after pulverization, melting, etc. was measured in an aqueous solvent using a laser diffraction particle size distribution analyzer SALD-7500 nano manufactured by Shimadzu Corporation. 10 , D 50 (median diameter), D 90 The particle size distribution was calculated.

[0092] (Specific surface area measurement / BET method) 1.0 g of each test example was weighed out and placed in a measurement cell. After pretreatment, the BET specific surface area was measured by nitrogen adsorption. For the measurement, an automatic specific surface area and pore distribution analyzer TriStar (registered trademark)-II 3020 manufactured by Shimadzu Corporation was used. The pretreatment was carried out under the following conditions: Degassing temperature: 300℃ Degassing time: 30 minutes Cooling time: 4 minutes

[0093] (Component analysis) The atomic composition of each test example was analyzed using an ICP (inductively coupled plasma atomic emission spectroscopy) analyzer ICP-MS (measurement of U) manufactured by Shimadzu Corporation. For the measurement, each test example was completely dissolved in a mixture of nitric acid and hydrofluoric acid to form a solution, which was then fed into the analyzer.

[0094] (Content of hollow particles of 5 μm or more by cross-sectional observation) Liquid epoxy resin ZX1059 (manufactured by Nippon Steel Chemical & Material Co., Ltd.) and the spherical inorganic composition (filler) prepared in the test examples were mixed, and then the curing agent Ethacure 100 (manufactured by Mitsui Fine Chemicals, Inc.) was added and mixed. At this time, the spherical inorganic composition (filler) was adjusted to 70 mass %. The mixture of resin and spherical inorganic composition was heated to 170°C to cure the resin. After curing, the cured resin was cut and the cross section was polished.

[0095] An ArBlade (registered trademark) 5000 (Hitachi High-Tech Corporation) was used for ion milling, and the cross section was osmium coated with osmium tetroxide gas and observed by SEM. Observation range: 9 mm 2 The number of particles containing voids within the spherical inorganic composition having an inner diameter (major axis) of 5 μm or more was counted.

[0096] (Content of hollow particles of 5 μm or more by X-ray CT observation) Liquid epoxy resin ZX1059 (manufactured by Nippon Steel Chemical & Material Co., Ltd.) and the spherical inorganic composition (filler) prepared in the test examples were mixed, and then the curing agent Ethacure 100 (manufactured by Mitsui Fine Chemicals, Inc.) was added and mixed. At this time, the spherical inorganic composition (filler) was adjusted to 70 mass %. The mixture of resin and spherical inorganic composition was heated to 170°C to cure the resin. After curing, the cured resin was cut and the cross section was polished.

[0097] The cured resin was scanned using a microfocus X-ray CT (Rigaku Corporation, nano-3DX). The setting conditions were 0.64 μm / voxel and the measurement range was 0.58 mm.3 After scanning, the analysis software VG Studio MAX was used to process the images and calculate the void volume inside the spherical inorganic composition. 3 , 150 μm 3 The number of voids was counted.

[0098] (Coarse grain content) The spherical inorganic composition prepared in each test example was sieved using a sieve with a mesh size of 10 μm or 5 μm. The mass before sieving and the mass of the particles remaining on the sieve were then measured, and test examples in which the amount of residue was 500 ppm or less were marked with "Good", and test examples in which the amount of residue was more than 500 ppm were marked with "Poor".

[0099] (Fillability) Liquid epoxy resin ZX1059 (manufactured by Nippon Steel Chemical & Material Co., Ltd.) was mixed with the spherical inorganic composition (filler) prepared in the test example. At this time, the spherical inorganic composition (filler) was adjusted to 80% by weight (mass %). The viscosity at 25°C was measured using a rheometer ARES-G2 (manufactured by TA Instruments) (shear rate 1 s -1 ) Then, the specimens were evaluated to see if they were 1500 Pa·s or less. Those below 1500 Pa·s were rated as "Good", and those above 1500 Pa·s were rated as "Poor".

[0100] (result) The results are shown in Tables 1, 2, 3, and 4 below. From the top to bottom, the types, average particle sizes (μm), specific surface areas (m 2 / g), cross-section observation of "5 μm or more hollow amount (pieces / cm 2 ), hollow volume of 10 μm or more (pcs / cm 2 ), void volume 35μm 3 or more particles (pcs / cm 2 ), void volume 150μm 3 or more particles (pcs / cm 2 ) and X-ray CT observation of "5 μm or more hollow amount (pieces / mm 3 ), hollow volume of 10 μm or more (pcs / mm 3 ), void volume 35μm 3 or more particles (pcs / mm 3 ), void volume 150μm 3or more particles (pcs / mm 3 )," fillability (good or bad), and U (uranium) content (ppb).

[0101] [Table 1]

[0102] [Table 2]

[0103] [Table 3]

[0104] [Table 4]

[0105] (Consideration) The smaller the average particle diameter of a spherical inorganic composition (the finer the particle size), the lower the proportion of hollow particles with large internal void volumes. However, fine particles have poor filling properties in resin. Therefore, they are not suitable for filler applications. Furthermore, in applications such as semiconductor encapsulation materials (fillers for encapsulation materials for semiconductor packages), filling properties are important for controlling the thermal expansion coefficient. To achieve both of these, by setting the average particle diameter to 0.5 μm or more, the spherical inorganic composition can also have sufficient filling properties.

[0106] In wafer-level packaging (WLP), when the encapsulant is polished and a redistribution layer is formed on top of it, the polishing exposes the internal voids of the particles filled in the encapsulant, allowing the resin of the redistribution layer to flow into the voids, reducing the flatness of the redistribution layer and making electrical conduction defects more likely. Therefore, understanding the content of particles with large internal void volumes is particularly important for encapsulants for WLP. Conventional cross-sectional observation techniques have made it difficult to accurately determine the internal voids of particles. In contrast, as disclosed in the examples, cross-sectional tomographic analysis allows for measurement of the internal voids of spherical inorganic compositions, improving the accuracy of evaluation. In particular, alumina spherical inorganic compositions can effectively address the above-mentioned problems of wafer-level packaging.

[0107] Spherical inorganic compositions of calcium titanate are advantageous for applications involving increasing the dielectric constant. When a filler is added to increase the dielectric constant, the inclusion of particles with a high hollowness can cause a decrease in the dielectric constant. In particular, when filling a substrate for high-frequency communications, the inclusion of particles with a high hollowness can cause a local decrease in the dielectric constant, leading to increased transmission loss, which is a problem. Therefore, the spherical inorganic composition of calcium titanate according to the embodiment has a reduced hollowness, making it possible to address the issue of dielectric constant modulation.

[0108] Spherical inorganic compositions of silica-alumina composite oxides are an excellent example of fillers for optical materials. For example, the refractive index of the filler itself can be matched to the matrix resin material used in photosensitive films, lenses, and adhesives used in photoelectric integration. When adding fillers to improve the strength of resin materials while allowing light to pass through, the inclusion of particles with a high hollow ratio can cause haze, reducing light transmittance and sensitivity. In this regard, the spherical inorganic compositions of silica-alumina composite oxides of the present embodiment have a reduced hollow ratio, which reduces diffuse reflection and addresses the haze issue.

Claims

1. A spherical inorganic composition containing inorganic raw materials other than simple silica as a main component, The spherical inorganic composition has an average particle size of 0.1 to 15 μm as measured by laser diffraction particle size distribution measurement, The spherical inorganic composition particles containing voids of 5 μm or more in diameter are 50 particles / mm ３ is as follows: The spherical particles of the inorganic composition containing voids of 10 μm or more in diameter are 5 particles / mm ３ is A spherical inorganic composition characterized by:

2. The spherical inorganic composition is filled into a resin material having a solid content of 70% by mass, and the resin composition is subjected to a cross-sectional analysis to obtain a particle size of 150 μm. ３ The spherical inorganic composition particles containing the above voids are 14 particles / mm ３ is as follows: 35 μm detected by the tomographic cross-section analysis ３ The spherical particles of the inorganic composition containing voids are 50 particles / mm ３ Below is the A spherical inorganic composition characterized by:

3. The spherical inorganic composition according to claim 2, wherein the cross-sectional analysis is performed by X-ray CT or FIB-SEM.

4. 2. The spherical inorganic composition according to claim 1, wherein the spherical inorganic composition comprises alumina, calcium titanate, or a silica-alumina composite oxide.

5. 2. The spherical inorganic composition according to claim 1, wherein the content of uranium element in the spherical inorganic composition is 100 ppb or less.

6. The spherical inorganic composition according to claim 4 , wherein the spherical inorganic composition is surface-treated with a silane compound.

7. A resin composition comprising the spherical inorganic composition according to claim 1 and a resin material for dispersing the spherical inorganic composition.

8. A slurry composition comprising the spherical inorganic composition according to claim 1 and a dispersion medium for dispersing the spherical inorganic composition.

9. A filler for a sealing material for semiconductor packages, comprising the spherical inorganic composition according to claim 1.

10. a dispersing step of dispersing a spherical inorganic composition excluding simple silica in a resin composition; a cross-sectional analysis step of performing a cross-sectional analysis of the spherical inorganic composition together with a resin composition using an X-ray CT or FIB-SEM; and a void calculation step of preparing a three-dimensional image from the tomographic cross-section analysis and calculating the diameter and volume of voids present in the spherical inorganic composition. A method for analyzing voids in a spherical inorganic composition, comprising:

11. The method for analyzing voids in a spherical inorganic composition according to claim 10, further comprising a curing step of curing the resin composition after the dispersing step.

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