Metal oxide particle material, method for producing same, slurry composition, resin composition, and filler for sealing material for semiconductor package

Abstract

The problem to be solved is to provide a metal oxide particle material which has high fillability into a resin material and has a small content of hollow particles and coarse particles. As a result of intensive studies, the present inventors have found that when a metal oxide particle material in which the range of D50 and the upper limit value of the content of coarse particles and hollow particles are set to fall within appropriate ranges is prepared and actually examined as a filler for a sealing material for a semiconductor package, the metal oxide particle material exhibits high performance, and the following invention was completed. That is, the metal oxide particle material of the present invention solving the above problem comprises a metal oxide as a main component, the metal oxide particle material having a D50 as obtained from laser diffraction particle size distribution measurement of 1.0-5.0 μm, a specific surface area of 1.0 m2 / g or more and 30 m2 / g or less, a content of coarse particles with a particle diameter of 5 μm or more of 300 ppm or less, and a content of hollow particles with a particle diameter of 5 μm or more of 4000 particles or less per 10 mg, wherein the viscosity of a resin composition obtained by filling a resin material with the metal oxide particle material at a solid concentration of 60% by mass is 170 Pa·s or less (shear rate is 1s-1hour).

Description

Metal oxide particle material, its manufacturing method, slurry composition, resin composition, and filler for sealing material for semiconductor package

[0001] The present invention relates to a metal oxide particulate material, a method for producing the same, a slurry composition, a resin composition, and a filler for a sealing material for a semiconductor package.

[0002] To protect semiconductor IC chips from dust, dirt, and moisture in the air, semiconductor packages are made by sealing the IC chips with a sealing material. The sealing material is a resin composition mainly composed of a resin with high heat and chemical resistance and metal oxide particles such as silica with a low thermal expansion coefficient and alumina, magnesia, and zinc oxide with high thermal conductivity.

[0003] There are several manufacturing methods for semiconductor packages depending on the application and required performance. Packages that require high functionality and small size, such as those used in mobile devices, are often produced using FOWLP or FOPLP technology.

[0004] Patent Publication No. 2021-161008

[0005] Although the structure of the finished package produced by FOWLP technology is very similar, the manufacturing process varies greatly depending on the package development company, and differences in the manufacturing process have a major impact on the performance of the finished package.

[0006] Starting from a wafer-level carrier, there are two main methods: the chip-first method, in which the silicon die is placed first, and the chip-last method, in which the rewiring structure is formed first. The chip-first method is further subdivided into face-up, in which the circuit side is placed on the carrier, and face-down, in which the circuit side is placed on the carrier.

[0007] These various FOWLP methods include a polishing process to smooth the surface of the semiconductor package containing the encapsulant after the IC chip is encapsulated. If hollow particles are present in the encapsulant or if cavities are formed in the encapsulant due to the inclusion of air bubbles or the like, depressions will form on the package surface after polishing, resulting in a decrease in surface smoothness and a deterioration in appearance, which can lead to a decrease in yield.

[0008] In particular, in manufacturing processes such as face-up processes, in which a rewiring layer is formed on a semiconductor package surface after polishing it, the presence of hollow particles in the encapsulant can result in copper wiring forming on depressions in the package surface. When the package expands and contracts due to changes in the temperature environment, the hollow spaces in the depressions can cause the copper wiring to break and disconnect. Without these cavities, the copper wiring is surrounded by the encapsulant, preventing it from breaking even when it expands and contracts. Furthermore, conventional copper wiring has a large line width exceeding 10 μm, making it highly rigid and less likely to break. However, as package functionality becomes more sophisticated and the line width becomes 10 μm or less, the rigidity of the copper wiring also decreases. Therefore, reducing the hollow particle content in the encapsulant is attracting attention.

[0009] Server packages differ in structure and manufacturing process from those described above. The package may be mounted on an interposer or similar device using a flip-chip configuration, and then the entire package is encapsulated. High-end packages may also be manufactured using two processes: underfilling the narrow gap under the chip and overmolding to protect the entire chip. However, there are also manufacturing methods that encapsulate both the chip and the surface at the same time. High fluidity is particularly important for bulk encapsulation. 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 encapsulant filler is highly desirable.

[0010] In order to meet the above-mentioned required characteristics, as semiconductor packages become smaller and wiring becomes finer, there is a need to precisely remove solid coarse particles, and the size of the coarse particles that need to be removed is also becoming smaller.However, from the perspective of the fluidity of the resin composition in which the filler and resin are mixed, spherical particles with a large mode diameter are desirable.

[0011] Therefore, fillers for the above-mentioned package encapsulants are required to have all the following properties: a large mode diameter, precise removal of coarse particles, high filling ability in resin, and a low hollow particle content.

[0012] Conventionally, metal oxide particles with a D50 of 2 μm or more and 5 μm or more in size have been used as a filler in the encapsulating material for such packages. However, hollow particles have not been removed, and therefore when the line width of the copper wiring is 5 μm or less, the risk of wire breakage and deterioration of the appearance result in a significant drop in the yield during package production.

[0013] Metal oxide particles with a D50 of 5-9 μm, from which solid particles (coarse particles) of 10 μm or larger have been removed, are also widely used. While their large D50 allows for high filling in resin, the presence of coarse particles of 5-10 μm size makes them unable to fill narrow gaps. The presence of hollow particles of 5-10 μm size also increases the risk of wire breakage and worsens the appearance, further lowering the yield during package production.

[0014] As a technique for removing hollow particles, Patent Document 1 describes a method for removing hollow particles having a D50 of 100 nm or more and 200 nm or less and a specific surface area of ​​30 m ２ / g or less and the number of hollow particles with a diameter of 2 μm or more is 1000 / 0.1 g or less, and a method for producing the same are disclosed. However, because the D50 is small, the viscosity when mixed with a resin is high, making it difficult to highly fill the resin with the filler, and it is not possible to achieve the low thermal expansion coefficient and high rigidity required for the package.

[0015] Furthermore, while synthetic silica produced by wet synthesis contains almost no hollow particles due to the manufacturing process, the particle size distribution is very sharp, making it difficult to improve its fillability in resin. One approach to adjusting the particle size distribution is to mix wet-synthesized silica of different particle sizes, but with wet synthesis, the amount of hydroxyl groups on the particle surface is high, making it difficult to improve its fillability in resin. A calcination process can be applied to reduce the amount of surface hydroxyl groups, but this causes the particles to fuse together. While particle fusion can be somewhat reduced by applying a crushing process, this process is lengthy and extremely expensive.

[0016] The present invention was completed in consideration of the above-mentioned circumstances, and aims to solve the problem of providing a metal oxide particle material that has high fillability in resin materials and a low content of hollow particles and coarse particles, a method for producing the same, a slurry composition, a resin composition, and a filler for an encapsulant for semiconductor packages.

[0017] As a result of extensive research, the inventors prepared a metal oxide particle material with an appropriate range for the D50 and the upper limit of the content of coarse particles and hollow particles, and actually examined it as a filler for an encapsulant for semiconductor packages. They found that it had high performance, and completed the following invention.

[0018] That is, the metal oxide particulate material of the present invention, which solves the above-mentioned problems, comprises a metal oxide as a main component, has a D50 measured by laser diffraction particle size distribution measurement of 1.0 μm or more and 5.0 μm or less, and has a specific surface area of ​​1.0 m ２ / g or more 30m ２ / g or less, the content of coarse particles having a particle size of 5 μm or more is 300 ppm or less, the content of hollow particles having a particle size of 5 μm or more is 4000 particles / 10 mg or less, the viscosity of the resin composition when filled into a resin material at a solid content concentration of 60 mass % is 170 Pa s or less (shear rate 1 s －１ (time).

[0019] Furthermore, the method for producing a metal oxide particulate material of the present invention, which solves the above-mentioned problems, is a method for producing a metal oxide particulate material of the present invention, comprising: a production step of passing a raw particle material containing a metal constituting the metal oxide particulate material as a main component through a high-temperature oxidizing atmosphere to cause deflagration, and then cooling the raw particle material to produce a raw metal oxide particulate material having a D50 of 1.0 μm or more and 5.0 μm or less; and a classification step of classifying the raw metal oxide particulate material until the content of coarse particles having a particle size of 5 μm or more is 300 ppm or less and the content of hollow particles having a particle size of 5 μm or more is 4,000 particles / 10 mg or less.

[0020] The metal oxide particulate material of the present invention, when dispersed in a resin material to form a resin composition, has excellent flow properties such as the ability to penetrate narrow gaps, and is particularly useful as a filler for semiconductor encapsulation materials because it can eliminate the risk of wire breakage and deterioration of appearance even in packages and server packages with copper wiring widths of 10 μm or less.

[0021] The metal oxide particle material, its manufacturing method, slurry composition, resin composition, and filler for semiconductor package encapsulant of the present invention will be described in detail below based on embodiments. The metal oxide particle material of this embodiment can be dispersed in a resin material to form a resin composition, or dispersed in a liquid dispersion medium to form a slurry composition. It can be particularly suitably used as a filler for semiconductor package encapsulant. (Metal oxide particle material and filler for semiconductor package encapsulant) The metal oxide particle material of this embodiment can be suitably used as is as a filler for semiconductor package encapsulant. It is preferably applied to semiconductors produced using FOWLP or FOPLP technology.

[0022] The metal oxide particle material of this embodiment is primarily composed of a metal oxide. "To be primarily composed of a metal oxide" means that the metal oxide particle material is composed of 50% or more of the mass of the metal oxide particle material, preferably 60% or more, 70% or more, 80% or more, 90% or more, 95% or more, etc. Whether or not a metal oxide is primarily composed of a metal oxide is determined for each individual metal oxide particle material. Therefore, when a particle material primarily composed of a metal oxide and a particle material not primarily composed of a metal oxide exist, the resulting mixture is a mixture of the metal oxide particle material of this embodiment and the other particle material. Examples of metal oxides include oxides containing Si, Al, Zr, Ti, etc., alone or in combination. The metal oxide may be amorphous, crystalline, or a mixture of both.

[0023] The metal oxide particle material has a D50 of 1.0 μm or more and 5.0 μm or less as measured by laser diffraction particle size distribution. Examples of D50 lower limits include 1.2 μm, μm, 1.4 μm, 1.6 μm, 1.8 μm, 2.0 μm, and 2.2 μm, and examples of D50 upper limits include 4.8 μm, 4.6 μm, 4.4 μm, 4.2 μm, 4.0 μm, 3.8 μm, 3.6 μm, and 3.4 μm. These upper and lower limits can be arbitrarily combined. D50 is a value measured by laser diffraction particle size distribution measurement, and is the particle size that accounts for 50% of the smallest particle size on a volume basis. Incidentally, D100 is the particle size that accounts for 100% of the smallest particle size. The D50 and D100 values ​​are calculated as values ​​within the measurement limit of laser diffraction particle size distribution measurement, and in reality, coarse particles and fine particles that cannot be detected by laser diffraction particle size distribution measurement exist. Therefore, there is no contradiction in the existence of particles with particle sizes larger than the D100 value.

[0024] The viscosity of the resin composition when filled into a resin material with a solid content concentration of 60% by mass is 170 Pa·s or less (shear rate 1 s －１ The resin material used is an epoxy resin obtained by mixing bisphenol A type epoxy resin and bisphenol F type epoxy resin in a 1:1 ratio (for example, ZX-1059 manufactured by Nippon Steel Chemical & Material Co., Ltd.).

[0025] The D50 value can be adjusted by controlling the particle size distribution by controlling the production conditions of the metal oxide particulate material, or by a classification operation or the addition of particulate materials with other particle size distributions. A suitable example of a classification operation is centrifugal separation using a cyclone or the like. The added particulate material can also be classified.

[0026] The metal oxide particulate material preferably has a linseed oil absorption of 2.7 g / 15 g or less, more preferably 2.5 g / 15 g or less, and even more preferably 2.3 g / 15 g or less. The linseed oil absorption was measured by adding linseed oil drop by drop to 15 g of the metal oxide particulate material, measuring the amount of linseed oil (g) added when fluidization was confirmed visually, and calculating the amount of linseed oil added (g) divided by the mass of the particulate material (15 g).

[0027] The metal oxide particulate material has a content of coarse particles having a particle size of 5 μm or more of 300 ppm or less, and can also be 200 ppm or less, 100 ppm or less, 50 ppm or less, 30 ppm or less, etc. The particle size of the coarse particles can also be 4.5 μm, 4 μm, etc. Coarse particles can be removed by classification as described below, for example, using a cyclone.

[0028] The specific surface area is 1.0 m ２ / g or more 30m ２ The lower limit of the specific surface area is 1.1 m ２ / g, 1.2m ２ / g, 1.4m ２ / g, 1.6m ２ / g, 1.8m ２ / g, 2.0 m ２ / g, 2.5m ２ / g, 3.0 m ２ / g, and the upper limit is 27.5 m ２ / g, 25m ２ / g, 22.5m ２ / g, 20m ２ / g, 17.5m ２ / g, 15m ２ / g, 12.5m ２ / g, 10m ２ / g, 7.5m ２ / g, 5.0 m ２ / g, 4.5m 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 the viscosity can be reduced when the material is used in a slurry composition or the like. The method for controlling the specific surface area is not particularly limited, but the specific surface area can be reduced by performing synthesis of the metal oxide particle material 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.

[0029] The number of hollow particles of 5 μm or larger is 4,000 particles / 10 mg or less, and the upper limit can be 3,500 particles / 10 mg, 3,000 particles / 10 mg, 2,500 particles / 10 mg, 2,000 particles / 10 mg, 1,500 particles / 10 mg, 1,000 particles / 10 mg, 750 particles / 10 mg, 500 particles / 10 mg, 250 particles / 10 mg, 200 particles / 10 mg, 150 particles / 10 mg, 100 particles / 10 mg, 50 particles / 10 mg, 40 particles / 10 mg, or 30 particles / 10 mg. The number of hollow particles can also be determined using the above-mentioned values ​​for the number of particles of 2 μm or larger. As described below, the particle size ranges for solid particles and hollow particles to be removed can be set using different principles, so the lower particle size limit can be set to different values.

[0030] The number of hollow particles can be reduced by classification using a filter or classification using a liquid that utilizes differences in specific gravity. Details will be explained in the manufacturing method section below. The upper limit of the number of hollow particles, 4,000 particles / 10 mg, is much lower than the upper limit of the coarse particle content, 300 ppm.

[0031] The number of hollow particles is measured by dispersing metal oxide particle material in a liquid and counting the number of hollow particles using an image analysis particle size distribution analyzer. The ratio of the refractive index of the liquid, ns, to the refractive index of the metal oxide particle material, nf, (ns / nf), is specified to be 0.98 to 1.02.

[0032] When an insoluble solid is dispersed in a liquid, if the refractive index of the solid is similar to that of the liquid, the solid is difficult to see in the liquid, and therefore the liquid is perceived as transparent even though the solid is dispersed in it.

[0033] In contrast, hollow particles in metal oxide particle materials have internal voids, and because of the difference in refractive index between them and the liquid, they can be optically observed. Therefore, solid particles become transparent and difficult to see, while hollow particles become specifically visible, allowing for counting of hollow particles.

[0034] The total amount of alkali metals and alkaline earth metals is preferably 100 ppm, 80 ppm or less, 50 ppm or less, or 30 ppm or less. This can be achieved by purifying the materials used in producing the metal oxide particle material. Since alkali metals and alkaline earth metals are oxidized and eluted or precipitated as ions, their use in encapsulation of semiconductor devices and the like can potentially have unexpected effects on the semiconductor device. For example, assuming the electrical conductivity (EC) of the water extract, it is desirable for it to be 10 μS / cm or less. Since a low content of alkali metals and alkaline earth metals is desirable to achieve this value, the above-mentioned content ranges are set. EC is measured as follows: Metal oxide particles are suspended in ion-exchanged water (conductivity 1 μS / cm or less) to form a 10% slurry, which is then placed in a pressure-resistant container and shaken at room temperature for 30 minutes. The supernatant liquid, which is then centrifuged, is measured for conductivity using a Horiba, Ltd. ES-51 electrical conductivity meter (EC meter).

[0035] The metal oxide particulate material of this 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 can be selected as needed for the surface treatment. Surface treatment can also be performed using a combination of two or more types selected from silane compounds and silazane compounds.

[0036] The metal oxide particulate material of this embodiment has an alpha ray generation rate of 0.001 c / cm ２-h or less. In particular, it is desirable that the uranium and thorium as alpha ray sources are 3 ppb or less (even more desirably 1 ppb or less). (Method for producing metal oxide particulate material) The method for producing a metal oxide particulate material of this embodiment comprises a production process, a classification process, and other processes adopted as necessary. The method for producing a metal oxide particulate material of this embodiment is a method that can suitably produce the metal oxide particulate material of this embodiment described above. -Production process The production process is a process in which a raw material particulate material is burned to produce a raw material metal oxide particulate material. The raw material particulate material produced has a volume average particle size of 1 μm or more and 5 μm or less. This volume average particle size range is the same as the volume average particle size of the metal oxide particulate material to be produced. Here, a classification process to remove coarse particles is performed later, but it is preferable to remove as few coarse particles as possible, so the volume average particle size is the same as that of the metal oxide particulate material to be produced.

[0037] This process is known as the VMC method, and the resulting raw metal oxide particle material is likely to have high sphericity, be dense, and have excellent electrical properties. The raw particle material is selected depending on the type of metal oxide contained in the metal oxide particle material to be produced. For example, if the metal oxide is silica, metallic silicon is used as the raw particle material; if the metal oxide is alumina, metallic aluminum is used; and if the metal oxide is zirconia, metallic zirconium is used. If the metal oxide contains multiple metal elements, metals corresponding to those elements are contained in the raw particle material. If multiple metals are contained, the raw particle material may be a mixture of particle materials made of the respective metals, or one particle may contain two or more metal elements.

[0038] The VMC method is a method for obtaining a raw metal oxide particle material by burning a combustible (such as hydrocarbon gas) with a burner in an oxygen-containing atmosphere to form a high-temperature chemical flame, and then adding raw material particles into the chemical flame in an amount sufficient to form a dust cloud, causing a deflagration. The high-temperature atmosphere is preferably an atmosphere of 2000°C or higher.

[0039] The VMC method works as follows: First, a container is filled with a gas containing oxygen, which is a reactive gas, and a chemical flame is formed in this reactive gas. Next, raw material particles are introduced into this chemical flame to form 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, causing the vapor of the contained metals to spread from the surface of the raw material particles 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 and oxygen gas mix, 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 improved reactivity, allowing for less energy input.

[0040] As this chain reaction of ignition progresses, the raw material particles themselves are destroyed and scattered, promoting flame propagation. After combustion, the generated gases are naturally cooled, forming a cloud of metal contained in the raw material particles. The resulting raw metal oxide particles are collected using a bag filter, an electrostatic precipitator, or the like.

[0041] The VMC method utilizes the principle of dust explosion. According to the VMC method, a large amount of raw metal oxide particle material can be obtained instantaneously. The obtained raw metal oxide particle material has an approximately spherical shape. By adjusting the particle size, input amount, flame temperature, etc. of the raw particle material to be added, it is possible to adjust the particle size distribution of the obtained raw metal oxide particle material. Furthermore, the raw particle material may be a metal alone, or particles made of a metal oxide (e.g., silica) can be added. By using metal oxide particles obtained by this method as the metal oxide particles to be added at the same time, the purity of the obtained raw metal oxide particle material can be maintained.

[0042] The raw particle material can also be surface-treated with a silane compound, a silazane compound, etc. The type of silane compound that can be used is not particularly limited, and those used in the surface treatment step described below can be used.

[0043] 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, but when dispersed in a liquid, it is preferable to spray the particles into the flame in a mist form. For example, it is preferable that the raw material particles are contained in an amount of about 10% to 80% by volume of the total.

[0044] The flame used is a flame in an oxidizing atmosphere. For example, a flame obtained by burning a flammable gas such as LPG, ammonia, or hydrogen in an atmosphere containing excess oxygen. Thermal plasma is also included in the flame.

[0045] The raw particle material made of metal introduced into the flame is vaporized by combustion and rapidly cooled to become raw silica particles made of silica. The obtained raw silica particles are recovered using a bag filter or the like. - Classification process The classification process is a process of classifying the raw metal oxide particle material until the content of coarse particles is below the above-mentioned upper limit and the content of hollow particles with a particle size of 5 μm or more is below the above-mentioned upper limit. The coarse particles consist of solid particles and hollow particles.

[0046] Classification procedures include centrifugation in a gas or solvent, separation by specific gravity in a liquid, and dry or wet sieving. Classification procedures are repeated until the desired particle size distribution is achieved in one run.

[0047] Centrifugation is a method suitable for removing solid particles from among coarse particles. It is desirable that the solvent used for centrifugation has a 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 approximately 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 to cause the coarse particles to settle and be removed.

[0048] To separate coarse particles consisting of hollow particles, it is preferable to separate hollow particles with a low specific gravity after dispersing them in a liquid. Separation in a liquid is preferably carried out 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 can be the same as the liquid used in centrifugation. Furthermore, since solid particles among the coarse particles settle quickly, while hollow particles settle slowly or not at all, removing the supernatant in conjunction with the operation for removing the coarse particles described above allows for the simultaneous removal of coarse particles consisting of solid particles and coarse particles consisting of hollow particles.

[0049] Furthermore, when classification using a filter is employed, it is carried out in the form of a dispersed slurry dispersed in a solvent. It is desirable to carry out the classification operation using a filter multiple times. When carrying out the classification operation multiple times, it is preferable to carry out the classification operation using a filter while changing from a filter with a large pore size to a filter with a small pore size. Other Processes A surface treatment process can be employed. The surface treatment process can be carried out at any time before, after, or during the classification process of the raw metal oxide particle material produced by the production process.

[0050] The surface treatment step is a step in which a raw metal oxide particulate material is surface-treated with a surface treatment agent such as a silane compound or a silazane compound, so that functional groups derived from the surface treatment agent are introduced onto the surface of the final metal oxide particulate material, or the surface treatment agent is attached to the surface of the final metal oxide particulate material.

[0051] The surface treatment is carried out by directly contacting the surface treatment agent (either liquid or gaseous) with the surface of the particles or by contacting the surface treatment agent dissolved in a solvent. In the surface treatment, the surface treatment agent can be heated after contacting the particles. When a classification operation in a liquid is employed in the classification step, the surface treatment step can also be carried out in the liquid.

[0052] The amount of the surface treatment agent used for the 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%, or the like, based on the amount of OH groups present on the surface of the particles to be treated, can be selected. An excessive amount exceeding 100% (120%, 150%, etc.) can also be selected. In this case, unreacted surface treatment agent remains on the surface of the particles.

[0053] The silane compound is not particularly limited, and examples thereof include those having a phenyl group, an alkyl group, a vinyl group, a methacrylic group, an epoxy group, a phenylamino group, an amino group, and a styryl group. (Resin Composition) The slurry composition of this embodiment is obtained by dispersing the above-mentioned metal oxide particle material in a resin material (including a resin material precursor). The mixing ratio of the metal oxide particle material to the resin material is not particularly limited. The resin material is not particularly limited, but examples include epoxy resin, acrylic resin, and silicone resin. It may also be a resin material precursor before curing. (Slurry Composition) The slurry composition of this embodiment is obtained by mixing the above-mentioned metal oxide particle material with a liquid dispersion medium (solvent, resin material precursor, etc.). The mixing ratio of the metal oxide particle material to the dispersion medium is not particularly limited. In addition to the above-mentioned resin material precursor, examples of the dispersion medium include MEK, MIBK, hexane, isopropanol, and other alcohols.

[0054] The metal oxide particulate material and the method for producing the same of the present invention will be described in detail below with reference to the following examples. (Test Example 1) A raw material particulate material made of metal silicon was charged into a high-temperature atmosphere, deflagrated, and then cooled to a D50 of 2.0 μm and a specific surface area of ​​2.0 m as measured by laser diffraction particle size distribution. ２ Thus, a raw metal oxide particle material consisting of silica of 0.1g / g was obtained (production step).

[0055] A cyclone was used to remove coarse particles with a particle size of 5 μm or more from the raw metal oxide particle material until the content was 300 ppm or less (classification process). After removing the coarse particles, 100 g of the resulting particle material was placed in a 500 mL plastic container, and 50 g of isopropyl alcohol was added as a solvent. The particles were dispersed for 5 minutes using a commercially available homogenizer to uniformly disperse the particles, producing a slurry. The slurry was then allowed to stand for 1.2 hours, and the supernatant layer (1 cm from the liquid surface, 95% of the depth) was removed using a dropper. The supernatant layer contained hollow particles that had accumulated in the supernatant layer due to the difference in specific gravity between hollow particles and solid particles, allowing the hollow particles to be effectively removed (hollow particle separation process within the classification process).

[0056] The remainder after removing the supernatant layer was transferred to a metal tray and dried in a semi-explosion-proof dryer at 130°C for 8 hours, yielding 41 g of metal oxide particulate material. Thereafter, in order to reduce the viscosity when mixed with the resin material, the material was surface-treated with 3-methacryloxypropyltrimethoxysilane as a surface treatment agent (surface treatment step), and the material was used as the test sample for this test example. (Test Example 2) A metal oxide particulate material was prepared using the same procedure as in Test Example 1, except that the hollow particle separation step was not performed, and the material was used as the test sample for this test example. (Test Example 3) A metal oxide particulate material was prepared using the same procedure as in Test Example 1, except that the hollow particle separation step and the surface treatment step were not performed, and the material was used as the test sample for this test example. (Test Example 4) Crushed silica was used as the raw material, and the material was introduced into a molten flame to form spheroids with a D50 of 3.5 μm and a specific surface area of ​​1.5 m. ２ The metal oxide particulate material was prepared by removing coarse particles of 10 μm or more in accordance with the method of Test Example 1, and used as the test sample in this Test Example. (Test Example 5) Crushed silica was used as the raw material, and the material was introduced into a molten flame to form a spheroidized product with a D50 of 5.0 μm and a specific surface area of ​​5.0 m. ２ The metal oxide particulate material was prepared by removing coarse particles of 10 μm or more in accordance with the method of Test Example 1, and used as the test sample in this Test Example. (Test Example 6) Crushed silica was used as the raw material, and the material was introduced into a molten flame to form a spheroidized product with a D50 of 10 μm and a specific surface area of ​​3.5 m. ２ / g, and a metal oxide particulate material prepared by removing coarse particles of 25 μm or more in accordance with the method of Test Example 1 was used as the test sample of this Test Example. (Test Example 7) A metal oxide particulate material (D50: 150 nm, D100: 270 nm, specific surface area: 21.3 m) was prepared based on Test Example 1 of JP 2021-161008 A. ２ / g, 104 particles / 0.1 g (=10 particles / 10 mg) of hollow particles of 2 μm or more were surface treated with 3-methacryloxypropyltrimethoxysilane to prepare a test sample for this test example.

[0057] Test Example 1 of JP 2021-161008 A is as follows: The raw particle material was silica produced by the VMC method, with a volume average particle size of 300 nm and a specific surface area of ​​17.8 m ２ / g was used.

[0058] The raw particle material was surface-treated with a silane compound, N-phenyl-3-aminopropyltrimethoxysilane, in an amount of 2% based on the mass of the raw particle material.

[0059] The obtained particulate material was dispersed in MEK to obtain a dispersion with a solids concentration of 20% by mass. This dispersion was subjected to sedimentation and removal of coarse particles by decantation in a centrifugal field under conditions of a centrifugal acceleration of 1700 G and a residence time of 2.8 minutes. The (centrifugal field residence time: minutes) / (classified slurry viscosity: mPa s) ratio was 1.4, and the (centrifugal acceleration: G) / (classified slurry viscosity: mPa s) ratio was 850. The dispersion was then classified once each using filters with pore sizes of 5 μm, 3 μm, and 1 μm to remove hollow particles. The classified dispersion was left to dry in a dryer at 160°C for 30 minutes, and the dried metal oxide particulate material was used as the test sample for this test example. Test Example 8: A 500 mL reaction vessel equipped with a stirrer was placed in a thermostatic bath, and 43 g of ethanol, 46 g of water, and 51 g of 25% by mass ammonia water were added. The mixture was heated to 50°C while being mixed with the stirrer. Next, 105 g of tetraethoxysilane was continuously added over 11 minutes while stirring the mixture. After the addition, the solution was filtered to obtain silica particles. The mixture was then dried at 130°C for 8 hours in a semi-explosion-proof dryer, and then calcined at 1000°C for 12 hours in a calcination furnace. The temperature rise time during calcination was 2 hours, and the temperature was allowed to naturally decrease after a 12-hour holding time. The obtained metal oxide particulate material was spherical and had a D50 of 0.7 μm. This metal oxide particulate material was used as the test sample for this test example. Test Example 9: A metal oxide particulate material was prepared using the same method as in Test Example 8, except that the amount of ethanol was changed to 75 g, and used as the test sample for this test example. The obtained metal oxide particulate material was spherical and had a D50 of 1.0 μm. (Test Example 10) A metal oxide particulate material was prepared by the same method as in Test Example 8, except that the amount of ethanol was changed to 100 g, and used as the test sample for this test example. The obtained metal oxide particulate material was spherical and had a D50 of 2.0 μm. (Test Example 11) A raw particle material (silica, volume average particle size 2.0 μm) obtained by the VMC method was dispersed in isopropyl alcohol using a high-pressure disperser to obtain a dispersion liquid (dispersed slurry) with a solid content concentration of 30 mass%.

[0060] Taking advantage of the difference in sedimentation rate depending on the particle size in the dispersion, solid coarse particles of 3 μm or more were removed using a centrifuge.

[0061] Next, classification was performed once using filters with pore sizes of 7 μm, 5 μm, and 3 μm, respectively, to remove coarse particles 3 μm or larger, including hollow particles, to obtain a classified slurry composition. The classified slurry was dried using a dryer to obtain a silica particle material, which was used as the test sample of this example. (Test Example 12) The same metal oxide particle material as in Test Example 1 was used as the test sample of this Test Example, except that only the hollow particle removal step was performed as the classification step and no surface treatment step was performed. (Test Example 13) 100 g of the raw metal oxide particle material obtained in the manufacturing process of Test Example 1 was subjected to the hollow particle separation step of Test Example 1 and then dried. 10 g of the sample was mixed with 10 g of the sample that had only been dried after the hollow particle separation step of Test Example 1 to obtain the test sample of this Test Example. (Test Example 14) The test sample of this Test Example was obtained in the same manner as in Test Example 1, except that the hollow particle separation step was replaced by a step of passing the material through a 5 μm pore filter three times. The sample that was passed through the filter only once had a hollow particle content of 4,200 particles / 10 mg. (Test Example 15) The test sample of this test example was a metal oxide particulate material obtained in the same manner as Test Example 1, except that the hollow particle separation step was replaced by a step of passing the material through a filter with a pore size of 5 μm twice. The test sample of this test example was a metal oxide particulate material obtained in the same manner as Test Example 1, except that the hollow particle separation step was replaced by a step of passing the material through a filter with a pore size of 5 μm twice. The hollow particle content of the sample that was passed through the filter only once was 980 particles / 10 mg. (Evaluation) For the test samples of each test example, Table 1 shows the D50, specific surface area (SSA), lower limit of the particle size of the removed coarse particles (top cut point), whether or not the surface was treated with methacrylsilane, viscosity when filled into epoxy resin, content of coarse particles with a particle size of 5 μm or more, content of hollow particles with a particle size of 5 μm or more, and defect rate when semiconductor packages were manufactured.

[0062] D50 is a value measured by laser diffraction particle size distribution measurement. SSA is a value measured by the BET method using nitrogen gas. The viscosity when filled into epoxy resin is the viscosity at 25°C when the test sample is uniformly dispersed in epoxy resin (ZX-1059, manufactured by Nippon Steel Chemical & Material Co., Ltd.) at a solid content concentration of 60 mass% (shear rate 1 s －１ ).

[0063] The contents of coarse particles and hollow particles were calculated from the values ​​counted by image analysis when the test sample was dispersed in a liquid. The number of coarse particles was calculated by counting the number of coarse particles contained in a dispersion liquid in which the test sample was dispersed at a concentration of 3% by mass in MEK as a dispersion medium using an image processing device (Sysmex Corporation: FPIA-3000). The amount of dispersion liquid counted was the amount in which 10 g of the test sample was dispersed.

[0064] The number of hollow particles was measured using the method described in paragraph 0046 of JP 2022-117398 A. Specifically, an image analysis particle size distribution analyzer (IF-3200, manufactured by JUSCO International Co., Ltd.) was used as the hollow particle detection device. First, a test solution with a test sample concentration of 30 mg / mL was prepared using a mixture of toluene and acetone at a ratio of 3:1 (by mass) as the dispersion medium. The resulting test solution was then subjected to ultrasonic treatment for 2 minutes. Each test solution was image-detected using the above-mentioned detection device, and the number of hollow particles in the test sample was counted (the number of hollow particles per 10 mg was expressed as the number). The long axis of each hollow particle was also measured, and the average value was calculated. The lens magnification of the detection device used was 4x, and the spacer thickness of the measurement section was 300 μm. Images were taken using a CMOS camera installed in the device, repeatedly until an amount equivalent to 10 mg of silica was obtained, and the obtained images were analyzed. In order to extract only hollow particles from the obtained images, only results with a circularity of 95% or more were extracted and analyzed. Here, when the number of coarse particles was 500 ppm or more and the number of hollow particles was 10,000 or more, it was marked with "xx."

[0065] The defect rate when semiconductor packages were produced was calculated from the number of hollow particles of 5 μm or larger found when a 1 cm x 1 cm area of ​​a sample was observed under a microscope after polishing the cured material obtained by mixing various test samples with liquid resin and curing agent and heating and curing them. The cured material was prepared by blending 3.8 g of ZX-1059 and 1 g of curing agent Ethacure 300 (Mitsui Chemicals Fine Co., Ltd.) with 16 g of test sample, and heating and curing at 175°C for 2 hours.

[0066] If the number of confirmed hollows of 5 μm or more was less than 10, it was rated as "good," if it was 10 to 300, it was rated as "fair," and if it was 300 or more, it was rated as "poor." If the viscosity when kneaded with liquid resin and hardener was very high, at 170 Pa·s or more, it was deemed unsuitable for packaging.

[0067] As is clear from the table, it was found that Test Examples 1, 14, and 15 had low package defect rates and could exhibit excellent performance as fillers for semiconductor package encapsulants. These two Test Examples satisfied all of the following requirements (1) to (5), and it was inferred that by satisfying these requirements, they could exhibit high performance as fillers for semiconductor package encapsulants.

[0068] (1) Test Examples 1-5 and 9-15 in which D50 is 1.0 μm or more and 5.0 μm or less, (2) SSA is 1.0 μm or less ２ / g or more 30m ２ / g or less, (3) Test Examples 1-3 and 7-15 where the content of coarse particles having a particle size of 5 μm or more is 300 ppm or less, (4) Test Examples 1 and 7-15 where the content of hollow particles having a particle size of 5 μm or more is 4000 particles / 10 mg or less, (5) where the viscosity of the resin composition when filled into a resin material at a solid content concentration of 60 mass% is 170 Pa s or less (shear rate of 1 s －１ ) Test Examples 1, 2, 4-6, 14, and 15.

Claims

1. The main component is a metal oxide, the D50 measured by laser diffraction particle size distribution measurement is 1.0 μm or more and 5.0 μm or less, and the specific surface area is 1.0 m ２ / g or more 30m ２ / g or less, the content of coarse particles having a particle diameter of 5 μm or more is 300 ppm or less, the content of hollow particles having a particle diameter of 5 μm or more is 4000 particles / 10 mg or less, the viscosity of the resin composition when filled into a resin material with a solid content concentration of 60 mass% is 170 Pa s or less (shear rate of 1 s －１ (when) a metal oxide particle material.

2. The metal oxide particulate material according to claim 1, which has been surface-treated with a silane compound.

3. A metal oxide particle material according to claim 1 or 2, in which the content of hollow particles having a particle size of 2 μm or more is 4,000 particles / 10 mg or less.

4. A metal oxide particulate material according to any one of claims 1 to 3, which has a linseed oil absorption of 2.7 g / 15 g or less.

5. A resin composition comprising the metal oxide particulate material according to any one of claims 1 to 4 and the resin material in which the metal oxide particulate material is dispersed.

6. A slurry composition comprising the metal oxide particulate material according to any one of claims 1 to 4 and a dispersion medium for dispersing said metal oxide particulate material.

7. A method for producing a metal oxide particulate material according to any one of claims 1 to 4, comprising: a production step of producing a raw metal oxide particulate material having a D50 of 1.0 μm or more and 5.0 μm or less by passing a raw particle material containing a metal constituting the metal oxide particulate material as a main component through a high-temperature oxidizing atmosphere to cause deflagration, and then cooling the raw metal oxide particulate material; and a classification step of classifying the raw metal oxide particulate material until the content of coarse particles having a particle diameter of 5 μm or more is 300 ppm or less and the content of hollow particles having a particle diameter of 5 μm or more is 4,000 particles / 10 mg or less.

8. The method for producing a metal oxide particle material according to claim 7, wherein the classification step includes a hollow particle separation step of dispersing the raw metal oxide particle material in a liquid dispersion medium and separating the hollow particles having a low specific gravity.

9. The method for producing a metal oxide particulate material according to claim 7 or 8, wherein the temperature of the high-temperature oxidizing atmosphere is 2000° C. or higher.

10. A filler for a sealing material for semiconductor packages, comprising the metal oxide particulate material according to any one of claims 1 to 4.