Spherical silica composition, resin composition, slurry composition, filler for semiconductor package sealant, and method for analyzing pores of spherical silica composition

Abstract

By accurately identifying the characteristics of the pores present in the particles of the spherical silica composition, the quality of the particles of the spherical silica composition is improved, and a spherical silica composition suitable for use as a filler for semiconductor packaging sealants is provided. The spherical silica composition, which has silica as its main component, is a spherical silica composition when filled into a resin material having a solid content concentration of 70 mass% of the spherical silica composition, wherein the number of particles of the spherical silica composition containing pores of 150 μm³ or larger detected by cross-sectional analysis of the resin composition is 14 particles / mm³ or less, and the number of particles of the spherical silica composition containing pores of 35 μm³ or larger detected by cross-sectional analysis of the resin composition is 60 particles / mm³ or less.

Description

Technology Field

[0001] The present invention relates to a spherical silica composition, a resin composition, a slurry composition, a filler for a semiconductor package sealant, and a method for analyzing pores of a spherical silica composition, and in particular, to a spherical silica composition having pores inside and a composition containing the same. Background Technology

[0002] Sealants are used to protect semiconductor IC chips from dust, dirt, and moisture in the air, and the IC chips are sealed to manufacture semiconductor packages. The sealants primarily utilize resin compositions consisting of resins with high heat and chemical resistance, and silica with a low coefficient of thermal expansion. Multiple manufacturing methods exist for semiconductor packages depending on various applications and required performance. For packages requiring high functionality and micro-size for mobile devices, FOWLP (Fan-Out Wafer Level Package) and FOPLP (Fan-Out Panel Level Package) are used.

[0003] Various FOWLP processes include a polishing process to smooth the surface of a semiconductor package containing a sealant after sealing an IC chip. If hollow particles are present in the sealant, or if voids are formed due to the incorporation of air bubbles, concave areas are formed on the package surface after polishing. This presents a problem where yield is reduced due to decreased surface smoothness and deterioration of the appearance. In particular, in the case of a manufacturing method where a redistribution layer is formed on the surface of a semiconductor package after polishing, if hollow particles are present in the sealant, copper wiring may be formed on the concave areas of the package surface. In this state, if the package undergoes expansion or contraction deformation due to changes in the temperature environment, the copper wiring may bend and break due to the presence of voids in the concave areas. If there are no voids, the copper wiring is surrounded by the sealant, so the wiring does not bend even if it undergoes expansion or contraction deformation. In addition, conventionally, the wire width of copper wiring was large, exceeding 10㎛, so the copper wire had high rigidity and was difficult to bend; however, as the package became more high-functional and miniaturized, the wire width became 10㎛ or less, and the rigidity of the copper wiring decreased. For this reason, attention is focused on reducing the content of hollow particles in the sealant (see References 1, 2, etc.).

[0004] Regarding server packages, the structure and manufacturing method differ from those described above. The package is loaded onto an interposer or similar device in a flip-chip structure, after which the entire package is sealed. Additionally, there are manufacturing methods that involve two processes: underfilling the narrow gap beneath the chip and overmolding to protect the entire chip, as well as methods that seal the bottom and top of the chip simultaneously. In particular, high fluidity is required for simultaneous sealing. For these package types, a surface polishing process is performed to smooth the surface of the package, and a low hollow particle content in the sealant filler is strongly required, just as it is for the above. Prior art literature

[0005] Japanese Patent Publication No. 2022-117398 and Japanese Patent Publication No. 2021-161008 The problem to be solved

[0006] In accordance with the aforementioned requirements, the miniaturization and fine wiring of semiconductor packages necessitate the precise removal of substantial coarse particles used in fillers, and the size of these coarse particles requiring removal is also decreasing. Furthermore, it is required to minimize voids within the aforementioned filler particles, and thus, from a quality control perspective, measuring these internal voids is critical.

[0007] However, in conventional particle pore measurement, the cross-section of the particle is exposed by embedding it in resin or similar material and grinding it. Consequently, the actual part of the particle and the void within it were measured. However, depending on the grinding position, the center of the void varies and does not necessarily correspond to the center of the filler, leading to positional misalignment. Consequently, even if the filler particle is cut to expose its cross-section, the exact diameter of the void sphere is not revealed; instead, the size and volume of the void are calculated based on the cross-sectional diameter at a location away from the center, resulting in significant errors. Furthermore, error factors such as deformation or clogging of the void due to loads during grinding were introduced. In particular, regarding wire breakage caused by concave areas during the formation of the redistribution layer, the likelihood of defects increases as the volume of the concave area increases. This is because the resin components of the redistribution layer flow into the concave area, causing a localized loss of flatness.

[0008] The present invention is made in light of the above points, and accurately identifies the characteristics of the pores present in the particles of the spherical silica composition to improve the quality of the particles of the spherical silica composition, provides a spherical silica composition suitable for resin compositions, slurry compositions, and fillers for semiconductor package sealants, and also provides a method for analyzing the pores of the spherical silica composition. means of solving the problem

[0009] That is, the spherical silica composition of the embodiment is a spherical silica composition having silica as the main component, and is a spherical silica composition when filled into a resin material having a solid content concentration of 70 mass% of the spherical silica composition, and is a 150 μm detected by cross-sectional analysis of the resin composition. 3 14 particles / mm of the spherical silica composition containing the above pores 3 It is less than or equal to 35㎛ detected by tomographic cross-section analysis. 3 60 particles / mm² of the spherical silica composition containing the above pores 3 It is characterized by the following.

[0010] In addition, regarding the spherical silica composition, the single-layer cross-sectional analysis may be performed using X-ray CT or FIB-SEM.

[0011] In addition, regarding the spherical silica composition, the average particle size determined by measuring the laser diffraction particle size distribution of the spherical silica composition may be 1.5 to 15 μm. In addition, the mode diameter determined by measuring the laser diffraction particle size distribution of the spherical silica composition may be 1.9 μm or more.

[0012] In addition, in the spherical silica composition, particles of the spherical silica composition containing pores with a diameter of 5 μm or more are 50 / mm 3 5 particles / mm² of a spherical silica composition containing pores with a diameter of 10㎛ or more, less than or equal to 3 It may be considered as less than

[0013] In addition, regarding the spherical silica composition, the spherical silica composition may contain 100 ppm or more of crystalline silica.

[0014] In addition, in the spherical silica composition, the content of uranium element in the spherical silica composition may be 5 ppb or less, and the content of sodium element in the spherical silica composition may be 100 ppb or less.

[0015] In addition, regarding the spherical silica composition, the spherical silica composition may include a surface treatment of a silane compound.

[0016] In addition, the composition may be a resin composition having a spherical silica composition and a resin material that disperses the spherical silica composition, or a composition having a dispersion medium that disperses the spherical silica composition, or a filler for a sealing material for a semiconductor package containing a spherical silica composition.

[0017] Furthermore, the method for analyzing pores of a spherical silica composition of an embodiment is characterized by comprising a dispersion process for dispersing the spherical silica composition in a resin composition, a cross-sectional analysis process for analyzing a cross-section of the spherical silica composition together with the resin composition using X-ray CT or FIB-SEM, and a pore calculation process for preparing a three-dimensional image from the cross-sectional analysis and calculating the diameter and volume of pores present in the spherical silica composition. Additionally, a curing process for curing the resin composition may be provided after the dispersion process. Effects of the invention

[0018] According to the spherical silica composition of the present invention, it is a spherical silica composition having silica as the main component, and is a spherical silica composition when filled into a resin material having a solid content concentration of 70 mass% of the spherical silica composition, wherein 150 μm detected by cross-sectional analysis of the resin composition 314 particles / mm of the spherical silica composition containing the above pores 3 It is less than or equal to 35㎛ detected by tomographic cross-section analysis. 3 60 particles / mm² of the spherical silica composition containing the above-mentioned pores 3 Since the following applies, the characteristics of the pores present in the spherical silica particles are accurately identified, thereby improving the quality of the spherical silica particles. Furthermore, by applying a method for analyzing the pores of the spherical silica composition, the precision of measuring the pores present in the spherical silica composition is enhanced. Specific details for implementing the invention

[0019] The spherical silica composition, resin composition, slurry composition, filler for sealing materials for semiconductor packages, and method for analyzing the pores of the spherical silica composition of the embodiments are described as follows. The spherical silica particles of the embodiments 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 sealing materials for semiconductor packages.

[0020] (Spherical silica composition and filler for sealant for semiconductor packages)

[0021] The spherical silica composition of the embodiment is in a particulate state and is suitablely adopted as is as a filler for sealing materials for semiconductor packages. As for semiconductors, it is preferable to apply it to those produced using FOWLP or FOPLP technology.

[0022] The spherical silica composition of the embodiment has silicon oxide (SiO₂) as the main component, and is composed of at least 50% silicon oxide based on the mass of the spherical silica composition, preferably with a content of at least 60%, at least 70%, at least 80%, at least 90%, and at least 95%. The spherical silica composition is a mixture of amorphous and crystalline materials, and the crystalline material contains at least 100 ppm of crystalline silica. This is because the spherical silica composition is derived from natural quartz.

[0023] Regarding the size of the spherical silica composition, D by laser diffraction particle size distribution measurement 50 (Median diameter) is 1.5㎛ or more and 15㎛ or less. D 50 As lower limits, 1.6㎛, 1.8㎛, 2.0㎛, and 2.2㎛ can be exemplified, and as upper limits, 14.0㎛, 11.0㎛, 9.0㎛, 8.0㎛, 7.0㎛, and 6.0㎛ are exemplified. These upper and lower limits can be combined arbitrarily. In addition, the mode diameter (most frequent diameter) is 1.9㎛ or more, preferably 2.3㎛ or more.

[0024] D 50 Silver is a value measured by laser diffraction particle size distribution, and is the particle size that is 50% by volume from the smallest particle size. For reference, D 100 The particle size from the smallest end represents the 100% particle size. Also, D 50 , D 100 The value of is calculated as a numerical value within the range of the measurement limit by laser diffraction particle size distribution measurement; however, in reality, there exist coarse and minute particles that cannot be detected by laser diffraction particle size distribution measurement. Therefore, D 100 There is no contradiction in the existence of particles with a particle size larger than the value of .

[0025] D 50 The value is controlled through the manufacturing conditions of the spherical silica composition. In addition, it is controlled by classification operations and the addition of particulate materials having different particle size distributions. For classification operations, centrifugal separation such as a cyclone is suitably used. Classification operations are also added for the particulate materials.

[0026] With respect to the spherical silica composition, when the resin material is filled with a solid content concentration of 75 mass%, the viscosity of the resin composition is 1500 Pa·s or less (shear rate of 1 s -1) is preferably 500 Pa·s or less, more preferably 400 Pa·s or less. As a resin material, an epoxy resin is used in which a bisphenol A type epoxy resin and a bisphenol F type epoxy resin are mixed in a 1:1 ratio (e.g., ZX-1059 manufactured by Nittetsu Chemical, Material Co., Ltd. is an example).

[0027] The specific surface area of ​​the spherical silica composition is 1.0 m² / g or more and 10 m² / g or less. Examples of lower specific surface area values ​​include approximately 0.2 m² / g, 0.5 m² / g, and 0.8 m² / g, and examples of upper specific surface area values ​​include approximately 6 m² / g, 5 m² / g, and 4 m² / g. The specific surface area is a value measured by the BET method using nitrogen. A smaller specific surface area value is desirable because it can reduce viscosity when used in slurry compositions, etc. The method for controlling the specific surface area is not particularly limited, and the specific surface area is adjusted by a method in which the amount of fine powder is reduced when synthesizing the spherical silica composition, or by reducing the amount of fine powder by controlling the residence time in the classifier to be long when classifying.

[0028] The voids contained in the spherical silica composition refer to hollow particles, which are bubbles generated during the manufacturing process of the spherical silica composition. It is self-evident that the fewer the voids (hollow particles), the better. However, they inevitably occur during the manufacturing of the spherical silica composition.

[0029] Regarding the pores (hollow particles), based on the case where the resin material is filled to achieve a solid content concentration of 70 mass% after the addition of a spherical silica composition, 150 μm 3 The particles of the spherical silica composition having the above pores are 14 / mm 3 Less than, 10 pieces / mm 3 Less than, 5 pieces / mm 3 It is less than or equal to, and most preferably, 0 pieces / mm 3 It is as follows. In addition, 35㎛ 3The particles of the spherical silica composition having the above pore size are 60 / mm 3 No more than 30 pieces / mm 3 No more than 15 pieces / mm 3 It is less than or equal to, most preferably, 10 pieces / mm 3 It is as follows.

[0030] In addition, based on the case where the resin material is filled so that the solid content concentration after adding the spherical silica composition is 70 mass%, the number of particles of the spherical silica composition having pores of 5 μm or more in diameter is 50 / mm 3 No more than 30 pieces / mm 3 Less than, 10 pieces / mm 3 It is less than or equal to, most preferably, 10 pieces / mm 3 The following applies. In addition, the particles of the spherical silica composition having pores with a diameter of 10 μm or more are 10 particles / mm 3 Less than, 5 pieces / mm 3 It is less than or equal to, most preferably, 3 pieces / mm 3 It is as follows.

[0031] The size of the pores (hollow particles) contained in each individual spherical silica composition was evaluated based on their diameter. In measuring the diameter of these pores (hollow particles), the spherical silica composition is embedded in a resin or the like, and then the resin block is cut to measure the diameter of the pores (hollow particles) from the cut surface of the spherical silica composition exposed in the cross-section. However, when cutting the resin block, the spherical silica composition is dispersed within the resin, so the location of the spherical silica composition that becomes the cut surface is completely random. For example, if the cut surface is located at a point away from the center of the sphere of the spherical silica composition, the pores exposed on the cut surface of the spherical silica composition are measured as having an apparently small diameter. It is impossible for the entire spherical silica composition to be cut precisely at the center of the sphere. Therefore, the measurement of the size of the pores (hollow particles) based on the cutting location lacked precision.

[0032] Therefore, in order to precisely measure the size of the pores (hollow particles), it is necessary to determine the diameter of the pores in multiple cross-sectional portions of the spherical silica composition. Taking this into account, cross-sectional analysis is performed in the embodiments. Specifically, X-ray CT or FIB-SEM is used for the analysis. When using X-ray CT, cross-sectional images of a resin mass in which the spherical silica composition is dispersed are captured. It is preferable to set the imaging interval (pitch) between tomographs to a fine range, such as 1 μm or less. From each tomograph, the diameter of the pores (hollow particles) present within each individual spherical silica composition is measured more sensitively. Thus, the volume of the pores (hollow particles) is calculated. Furthermore, even if the shape of the pores is distorted rather than spherical, the volume of the distorted pores can also be calculated from image analysis of the aggregated cross-sectional images.

[0033] In the use of FIB-SEM, a concentrated ion beam is irradiated and scanned onto a mass of resin in which a spherical silica composition is dispersed, and the surface is gradually ground down in a fine range such as 1 μm or less. Thus, the pores (hollow particles) present within the individual spherical silica composition are gradually exposed. Thus, the diameter of the pores present within the individual spherical silica composition is measured according to the amount (depth) of grinding caused by the ion beam irradiation. Even with the use of FIB-SEM, the volume of the pores (hollow particles) is calculated, and it is also possible to measure pores with distorted shapes.

[0034] The measurement numbers described above are derived from analysis using X-ray CT or FIB-SEM. Under the measurement conditions of X-ray CT or FIB-SEM, the pore diameter at which maximum diameter is observed is observed by cutting at a pitch of 1 µm or less, or 3D data is constructed, and the pore diameter and volume within the particle are calculated based on the contrast difference between the surrounding resin, the spherical silica composition, and the pores. Alternatively, X-ray CT data is acquired under conditions where the voxel size is 2 µm or less, and the pore diameter and volume within the particle are calculated based on the contrast difference. In the analysis using X-ray CT or FIB-SEM, the analysis range is 0.5 mm 3 That is all.

[0035] Essentially, a critical aspect is accurately measuring the number of hollow particles with large pore volumes. In practice, the pore volume (volume) measured using methods such as X-ray CT, as in the embodiment, deviates from the theoretical value calculated from the pore diameter. This is because the shape of the pores within the particles is often not perfectly spherical. By performing a cross-sectional analysis of the embodiment, the diameter and volume of the pores (hollow particles) for each individual spherical silica composition can be accurately detected and calculated. Consequently, the precision of quality control for the finished spherical silica composition is improved. In particular, this contributes significantly to improving the yield when processing wiring with finer line widths.

[0036] (Method for analyzing pores in spherical silica compositions)

[0037] The method for analyzing the pores of a spherical silica composition is summarized as follows. First, the spherical silica composition is dispersed in a resin composition. The resin composition described above is used. The solid content concentration of the spherical silica composition in the resin composition is prepared to be 60 to 80 mass%, preferably 70 mass% (dispersion process). The dispersion process into the resin is intended to fix the position of individual particles of the spherical silica composition for the analysis of subsequent measurements. Additionally, after the dispersion process, a curing process is added to cure the resin composition. In this curing process, heating of the resin composition and ultraviolet irradiation of the resin composition are performed, and the resin composition is prepared as a cured resin product. As is obvious, a thermosetting resin or an ultraviolet curable resin is selected for the resin composition.

[0038] The spherical silica composition, along with the resin composition, is analyzed in a cross-section using X-ray CT or FIB-SEM (cross-section analysis process). The method of cross-section analysis is as described above. A three-dimensional image is prepared from the cross-section analysis, and the diameter and volume of the pores present in the spherical silica composition are calculated (pore calculation process). The cross-section analysis process and the pore calculation process can be processed consistently, and appropriate adjustments such as the analysis range and voxel size are made to calculate the maximum diameter and volume of the pores (hollow particles) present in each spherical silica composition.

[0039] It is preferable that the total amount of alkali metals and alkaline earth metals in the spherical silica composition of the embodiment be 100 ppm, 80 ppm or less, 50 ppm or less, or 30 ppm or less. The reduction of alkali metals and alkaline earth metals can be achieved by purifying the material when manufacturing the spherical silica composition. In particular, the content of the sodium element in the spherical silica composition is 100 ppb or less, preferably 50 ppb or less, and more preferably 30 ppb or less.

[0040] Since alkali metals and alkaline earth metals are oxidized and elute or precipitate as ions, applying them to sealing materials for semiconductor devices may result in unexpected effects on the semiconductor device. For example, when considering the conductivity (EC) of a water extract, it is desirable that it be 10 μS / cm or less. Since it is desirable to reduce the content of alkali metals and alkaline earth metals to achieve a lower value, the aforementioned content range is established. The conductivity (EC) is measured as follows. A spherical silica composition is suspended in ion-exchanged water (conductivity 1 μS / cm or less) to form a 10% slurry, which is then introduced into a pressure vessel and shaken at room temperature for 30 minutes. Afterward, the supernatant liquid obtained by centrifugal settling is measured using a conductivity meter (EC system) ES-51 manufactured by Horiba Seisakusho Co., Ltd.

[0041] The spherical silica 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 and the silazane compound are not particularly limited, and surface treatment can be performed by selecting a silane compound or a silazane compound having an appropriate functional group as needed. It is also possible to perform surface treatment by a combination of two or more types selected from silane compounds and silazane compounds.

[0042] For the spherical silica composition of the embodiment, the α-ray generation amount is 0.001 c / cm 2 It is desirable that it be less than or equal to ·h. In particular, it is desirable that uranium and thorium as α-sources each be less than or equal to 5 ppb, preferably less than or equal to 3 ppb, and more preferably less than or equal to 1 ppb.

[0043] (Method for manufacturing metal oxide particle materials)

[0044] The method for manufacturing a spherical silica composition of the embodiment comprises a manufacturing process, a classification process, and other processes employed as necessary.

[0045] · Manufacturing process

[0046] The manufacturing process is a process of manufacturing a spherical silica composition by burning raw particle materials. The raw particle materials being manufactured have a volume average particle size of 1 μm or more and 15 μm or less. This range of volume average particle sizes is the same range as the volume average particle size of the spherical silica composition being manufactured. Here, a classification process to remove coarse particles is performed later, but it is preferable to remove as few coarse particles as possible and to have a volume average particle size equivalent to that of the spherical silica composition being manufactured.

[0047] The manufacturing process is a method for producing spherical oxide fine particles using the deflagration phenomenon of metal powder, known as the so-called VMC method (Vaporized Metal Combustion Method). The spherical silica composition produced by the VMC method exhibits high sphericity, density, and excellent electrical properties. Metallic silicon is used as the raw particle material. The VMC method involves burning a combustible agent (such as hydrocarbon gas) with a burner in an oxygen-containing atmosphere to form a chemical salt as a high-temperature atmosphere, introducing an amount of raw particle material into this chemical salt sufficient to form a dust cloud, and inducing deflagration to obtain a spherical silica composition. An atmosphere of 2000°C or higher is preferred as the high-temperature atmosphere.

[0048] The operation of the VMC method is explained as follows. First, a container is filled with a gas containing oxygen, which is the reaction gas, and a chemical flame is formed within this reaction gas. Subsequently, raw particle material is introduced into this chemical flame to form a dust cloud. Then, thermal energy is imparted to the surface of the raw particle material by the chemical flame, causing the surface temperature of the metal constituting the raw particle material to rise, and the vapor of the metal contained therein spreads from the surface of the raw particle material to the surroundings. This vapor reacts with the oxygen gas to ignite and generate a flame. The heat generated by this flame further promotes the vaporization of the raw particle material, and the generated vapor mixes with the oxygen gas, causing a chain reaction of ignition propagation. Therefore, the smaller the particle size of the raw particle material, the larger the specific surface area and the better the reactivity, allowing for a reduction in the energy required.

[0049] In addition to the preparation of a spherical silica composition by the VMC method described above, a spherical silica composition is also prepared by the flame melting method. In the preparation of a spherical silica composition by the flame melting method, the crystalline silica used as a raw material is crushed to, for example, 5 μm or less, and granulation is performed according to the desired particle size. Alternatively, heating exceeding, for example, 1000°C is performed to gasify the moisture within the pores contained in the crystalline silica, thereby reducing the pores.

[0050] As a chain reaction of ignition proceeds in this manner, the raw particle material itself is destroyed and scattered, promoting flame propagation. As the generated gases naturally cool after combustion, a cloud of metal contained in the raw particle material is formed. The obtained spherical silica composition is collected by bag filters, electrostatic precipitators, etc.

[0051] The VMC method utilizes the principle of dust explosion, and according to the VMC method, a large amount of spherical silica composition is obtained instantaneously. The obtained spherical silica composition forms a roughly spherical shape. It is possible to control the particle diameter distribution of the obtained spherical silica composition by adjusting the particle diameter, input amount, flame temperature, etc., of the input raw particle material. In addition, even if metallic silicon is used alone as the raw particle material, it is possible to add silica (quartz). The raw particle material may also undergo surface treatment using silane compounds, silazane compounds, etc. The types of silane compounds that can be used are not particularly limited, and those used in the surface treatment process described later may be adopted.

[0052] The raw particle material is burned by introducing it into a flame while dispersed in a carrier. The rate at which the raw particle material is introduced into the flame is not particularly limited. As the carrier, gases such as nitrogen, argon, and air, or liquids such as water and alcohol may be selected. There are no particular limitations on how it is dispersed, and when dispersed in a liquid, it is preferable to introduce it into the flame by spraying it in the form of a mist. For example, it is preferable to include an amount of raw particle material of about 10% to 80% based on the total volume.

[0053] An oxidizing atmosphere flame is employed as the flame. For example, a flame obtained by burning combustible gases such as LPG, ammonia, or hydrogen in an atmosphere containing an excess of oxygen can be cited. Additionally, thermal plasma is also included in the definition of a flame. Raw material particles introduced into the flame vaporize through combustion and, upon rapid cooling, become raw silica particles composed of silica. The obtained raw silica particles are recovered using a bag filter or the like.

[0054] · Classification process

[0055] The classification process is a process of classifying the raw metal oxide particle material until the particle size distribution is such that the content of coarse particles is below the upper limit specified above, and the content of hollow particles with a particle size of 5 μm or more is below the upper limit specified above. The coarse particles consist of solid particles and hollow particles. Classification operations include centrifugal separation in a gas or solvent, separation by specific gravity in a liquid, or sieving in a dry or wet manner. The process is repeated until the desired particle size distribution is achieved in a single classification operation.

[0056] Centrifugation is a suitable method for removing solid particles from coarse particles. It is preferable 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 dispersed in MEK at a concentration of about 10 mass% to 30 mass% (particularly 15 mass% to 25 mass%). In wet centrifugation, coarse particles can be separated by applying centrifugal force to the slurry to cause the coarse particles to settle and be removed.

[0057] To separate coarse particles consisting of hollow particles, it is preferable to separate the hollow particles with a lighter specific gravity after dispersing them in a liquid. Separation in the liquid is preferably performed by removing the hollow particles present in the supernatant after settling or applying centrifugal force following dispersion (hollow particle separation process). The liquid used may be the same as the liquid used in centrifugal separation. Furthermore, since solid particles among the coarse particles settle rapidly while hollow particles settle slowly or do not settle at all, the coarse particles consisting of solid particles and the coarse particles consisting of hollow particles can be removed simultaneously by removing the supernatant in parallel with the operation for removing the coarse particles described above. Additionally, if classification by filter is employed, it is performed in the state of a dispersed slurry dispersed in a solvent. It is preferable to perform the classification operation by filter multiple times. When performing multiple times, it is preferable to perform the classification operation by filtering while changing from a filter with a large pore diameter to a filter with a small pore diameter.

[0058] · Other processes

[0059] The surface treatment process can take place at any point before, during, or after the classification process for the spherical silica composition produced by the manufacturing process. The surface treatment process is a process of surface treating the spherical silica composition with a surface treatment agent, such as a silane compound or a silazane compound. Functional groups derived from the surface treatment agent are introduced or the surface treatment agent is attached to the surface of the finally produced spherical silica composition.

[0060] Surface treatment is performed by directly contacting the surface treatment agent with the surface of the particles (either in a liquid or gaseous state) or by contacting it while dissolved in a solvent. Surface treatment is heating after contacting the surface treatment agent with the particles. When a classification operation in a liquid is employed in the aforementioned classification process, the surface treatment process is also carried out in that liquid.

[0061] 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., is selected based on the amount of OH groups present on the surface of the particles to be treated. In addition, it is also possible to select an excess amount exceeding 100% (120%, 150%, etc.). In that case, a surface treatment agent that does not react with the surface of the particles remains. As for the silane compound, it is not particularly limited, and examples include compounds having phenyl groups, alkyl groups, vinyl groups, methacrylic groups, epoxy groups, phenylamino groups, amino groups, styryl groups, etc.

[0062] (Resin composition)

[0063] The slurry composition of the embodiment is a composition prepared by dispersing the spherical silica composition described above in a resin material (including a resin material precursor). The mixing ratio of the spherical silica composition and the resin material is not particularly limited. Suitable resin materials include epoxy resin, acrylic resin, silicone resin, etc. Additionally, it may be a resin material precursor before curing.

[0064] (Slurry composition)

[0065] The slurry composition of the embodiment is a composition prepared by mixing the spherical silica composition described above with a liquid dispersion medium (solvent, resin material precursor, etc.). The mixing ratio of the spherical silica composition and the dispersion medium is not particularly limited. In addition to the resin material precursor described above, the dispersion medium may include alcohols such as MEK, MIBK, hexane, and isopropanol.

[0066] Examples

[0067] A spherical silica composition of an embodiment, its manufacturing method, and its analysis method were prepared and carried out based on the following.

[0068] (Test Example 1)

[0069] Raw crystalline silica (manufactured by Admatex, Inc., silicon oxide: average particle size: 10 μm, hereinafter the same) was ground to an average particle size of 4 μm or less, and 3% by weight of silicon binder KR-500 (manufactured by Shin-Etsu Chemical Co., Ltd.) was added in methyl ethyl ketone as an organic solvent. After drying, particle size adjustment was performed using a ball mill to form granules of 10 μm. The said granules were introduced into a melting furnace and spheroidized. In addition, silica synthesized by the VMC method with an average particle size of 0.3 to 2.0 μm was added to achieve a close-packing design. Furthermore, surface treatment was performed using an epoxysilane coupling agent.

[0070] (Test Example 2)

[0071] The raw crystalline silica was ground to an average particle size of 8 μm and fed into a melting furnace to be spherical. The obtained spherical silica was classified (sieved) through a mesh of 20 μm. Subsequent treatment was performed in the same manner as in Test Example 1.

[0072] (Test Example 3)

[0073] Raw crystalline silica was ground to an average particle size of 4 μm and fed into a melting furnace to be spherical. The obtained spherical silica was classified into a mesh of 10 μm. Subsequent treatment was performed in the same manner as in Test Example 1.

[0074] (Test Example 4)

[0075] The raw crystalline silica was ground to an average particle size of 4 μm and fed into a melting furnace to be spherical. The obtained spherical silica was classified by airflow (using a cyclone) to a size of 20 μm. Subsequent treatment was performed in the same manner as in Test Example 1.

[0076] (Test Example 5)

[0077] Raw crystalline silica was ground to an average particle size of 4 μm and fed into a melting furnace to be spherical. The obtained spherical silica was classified into a mesh of 20 μm. Subsequent treatment was performed in the same manner as in Test Example 1.

[0078] (Test Example 6)

[0079] Raw crystalline silica was ground to an average particle size of 3 μm and fed into a melting furnace to be spherical. The obtained spherical silica was classified by a 10 μm air stream. Subsequent treatment was performed in the same manner as in Test Example 1.

[0080] (Test Example 7)

[0081] Spherical silica of 2 μm obtained by the VMC method was classified to 5 μm by air stream classification. Then, silica synthesized by the VMC method with an average particle size of 0.2 μm was blended to achieve a close-packed design. In addition, surface treatment with an aminophenylsilane coupling agent was performed.

[0082] (Test Example 8)

[0083] Spherical silica of 2 μm obtained by the VMC method was classified to 5 μm by wet classification in an aqueous medium and dried. Then, silica synthesized by the VMC method with an average particle size of 0.2 μm was blended to achieve a close-packed design. In addition, surface treatment with an aminophenylsilane coupling agent was performed.

[0084] (Test Example 9)

[0085] Spherical silica of 2 μm obtained by the VMC method was classified into 5 μm by wet classification in an aqueous medium and dried. Then, wet-synthesized nano-silica with an average particle size of 50 nm was blended to achieve a close-packed design. In addition, surface treatment with an aminophenylsilane coupling agent was performed.

[0086] (Test Example 10)

[0087] Raw crystalline silica was ground to an average particle size of 10 μm and fed into a melting furnace to be spherical. The obtained spherical silica was classified into a mesh of 24 μm. Subsequent treatment was performed in the same manner as in Test Example 1.

[0088] (Test Example 11)

[0089] Spherical silica of 2 μm obtained by the VMC method was classified to 5 μm by wet classification in an aqueous medium and dried. Then, VMC-synthesized silica with an average particle size of 0.3 μm was blended to achieve a close-packed design. In addition, surface treatment with an aminophenylsilane coupling agent was performed.

[0090] (Test Example 12)

[0091] Spherical silica of 1.5 μm obtained by the VMC method was classified to 5 μm by air stream classification. Then, VMC-synthesized silica with an average particle size of 0.3 μm was blended to achieve a close-packed design. In addition, surface treatment with an aminophenylsilane coupling agent was performed.

[0092] (Test Example 13)

[0093] Spherical silica of 1.5 μm obtained by the VMC method was classified to 3 μm by wet classification in an aqueous medium and dried. Then, VMC-synthesized silica with an average particle size of 0.2 μm was blended to achieve a close-packed design. In addition, surface treatment with an aminophenylsilane coupling agent was performed.

[0094] (Particle size distribution measurement)

[0095] For each test example, the particle diameter after grinding, melting, and mixing was measured in an aqueous medium using a laser diffraction particle size distribution measuring device SALD-7500nano manufactured by Shimadzu Corporation. In addition, D 10 , D 50 (Median diameter), D 50 The particle size distribution of was calculated.

[0096] (Specific surface area measurement / BET method)

[0097] 1.0 g of each test sample was weighed, placed into a measuring cell, and after pretreatment, the BET specific surface area value was measured by the nitrogen adsorption method. For the measurement, the TriStar (registered trademark)-II 3020 automatic specific surface area and pore distribution measuring device manufactured by Shimadzu Seisakusho Co., Ltd. was used. Pretreatment was performed under the following conditions.

[0098] Degassing temperature: 200℃

[0099] Degassing time: 30 minutes

[0100] Cooling time: 4 minutes

[0101] (Component Analysis)

[0102] When analyzing the atomic composition contained in each test example, an ICP (Inductively Coupled Plasma Emission Spectrometry) device manufactured by Shimadzu Corporation, ICP-MS (measurement of U), and ICP-OES (measurement of silica and other impurities) were used. For the measurement, each test example was completely dissolved in a mixture of nitric acid and hydrofluoric acid to form a solution, and then supplied to the device.

[0103] (Crystalline silica content)

[0104] Using an X-ray diffraction apparatus manufactured by Rigaku Co., Ltd., the crystal content was calculated by dividing the value of the peak intensity (cps) at 2θ=26.6° of each test sample by the intensity of 100% crystalline silica.

[0105] (Content of hollow particles larger than 5㎛ based on cross-sectional observation)

[0106] After mixing the liquid epoxy resin ZX1059 (manufactured by Nittetsu Chemical & Material Co., Ltd.) and the spherical silica composition (filler) prepared in the test example, the curing agent Etacure 100 (manufactured by Mitsui Chemical & Fine Co., Ltd.) was added and mixed. At this time, the spherical silica composition (filler) was prepared at 70 mass%. The mixture of the resin and the spherical silica composition was heated to 170°C to cure the resin. After curing, the cured resin product was cut and the cross-section was polished.

[0107] For ion milling, an ArBlade (registered trademark) 5000 (manufactured by Hitachi High-Tech Co., Ltd.) was used to coat the cross-section with osmium tetroxide gas, and the results were observed by SEM. The observation range was 9 mm. 2 The number of particles containing pores within a spherical silica composition with an internal diameter (long diameter) of 5㎛ or more was measured.

[0108] (Content of hollow particles larger than 5㎛ based on X-ray CT observation)

[0109] After mixing the liquid epoxy resin ZX1059 (manufactured by Nittetsu Chemical & Material Co., Ltd.) with the spherical silica composition (filler) prepared in the test example, the curing agent Etacure 100 (manufactured by Mitsui Chemical & Fine Co., Ltd.) was added and mixed. At this time, the spherical silica composition (filler) was prepared at 70 mass%. The mixture of the resin and the spherical silica composition was heated to 170°C to cure the resin. After curing, the cured resin product was cut, and the cross-section was polished.

[0110] The resin cured product was scanned by a microfocus X-ray CT (Rigaku Manufacturing Co., Ltd., nano-3DX). The setting conditions were 0.64 µm / voxel, and the measurement range was 0.58 mm. 3 ...was done. For image processing after scanning, the pore volume inside the spherical silica composition was calculated using the analysis software VG Studio MAX. And, 35㎛ 3 , 150㎛ 3 The above number of pores was counted.

[0111] (Filling)

[0112] Liquid epoxy resin ZX1059 (manufactured by Nittetsu Chemical & Material Co., Ltd.) and the spherical silica composition (filler) prepared in the test example were mixed. At this time, the spherical silica composition (filler) was prepared at 75 wt% (mass%). The viscosity at 25°C was measured using a rheometer ARES-G2 (manufactured by TA Instruments) (shear rate at 1 s -1). And, whether it was 1500 Pa·s or less was evaluated. 1500 Pa·s or less was marked as “○”, and 1500 Pa·s or more was marked as “×”.

[0113] (result)

[0114] The series of results is shown in Tables 1, 2, and 3 below. In order from the top column, the values ​​are average particle size (㎛), mode diameter (㎛), specific surface area (m² / g), viscosity at 75 mass% packing (Pa·s), packing capacity (○ or ×), crystalline silica content (present or absent), and hollows of 5㎛ or larger (pieces / ㎝). 2 ), hollow volume of 10㎛ or more (pieces / cm) 2 ), maximum diameter 5㎛ or more, hollow volume (pieces / mm) 3 ), maximum diameter 10㎛ or more, hollow volume (pieces / mm) 3 ), pore volume 35㎛ 3 Abnormal particles (pieces / mm) 3 ), pore volume 150㎛ 3 Abnormal particles (pieces / mm) 3 It is an item for U (uranium) content (ppb) and Na (sodium) content (ppb).

[0115] [Table 1]

[0116]

[0117] [Table 2]

[0118]

[0119] [Table 3]

[0120]

[0121] (Consideration)

[0122] For spherical silica compositions, as the average particle diameter decreases (becomes finer), the content ratio of hollow particles with a large internal pore volume decreases. However, in fine particles, the packing ability into the resin decreases. Therefore, it is not suitable for filler applications. In addition, for semiconductor sealing materials (fillers for semiconductor package sealing materials), packing ability becomes important for controlling the thermal expansion rate. To achieve this compatibility, by making the average particle diameter 1.5 μm or more and the mode diameter 1.9 μm or more, the spherical silica composition can possess sufficient packing ability.

[0123] In Wafer Level Packages (WLP), when a sealant is polished and a redistribution layer is formed thereon, the internal voids of the particles filled in the sealant are exposed by the polishing. As the resin of the redistribution layer flows into these voids, the flatness of the redistribution layer deteriorates, making it prone to conductivity failures. For this reason, determining the content of particles with large internal void volumes is more important for sealants used in Wafer Level Packages (WLP). In conventional cross-sectional observation methods, it was difficult to accurately determine the internal voids of the particles. In contrast, as disclosed in the examples, the internal voids of the spherical silica composition can be measured by cross-sectional cross-sectional analysis, thereby improving the precision of the evaluation.

Claims

Claim 1 A spherical silica composition having silica as the main component, a spherical silica composition when filled into a resin material having a solid content concentration of 70 mass% of the spherical silica composition, and a 150 μm detected by single-layer cross-sectional analysis of the resin composition 3 14 particles / mm of the spherical silica composition containing the above pores 3 Below, and 35㎛ detected by the above single-layer cross-sectional analysis. 3 60 particles / mm² of the spherical silica composition containing the above-mentioned pores 3 A spherical silica composition characterized by the following: Claim 2 A spherical silica composition according to claim 1, wherein the cross-sectional analysis of the above-mentioned layer is performed by X-ray CT or FIB-SEM. Claim 3 In claim 1, the spherical silica composition having an average particle size of 1.5 to 15 μm as determined by laser diffraction particle size distribution measurement. Claim 4 A spherical silica composition according to claim 1, wherein the mode diameter determined by laser diffraction particle size distribution measurement of the spherical silica composition is 1.9 μm or more. Claim 5 In claim 1, the particles of the spherical silica composition containing pores with a diameter of 5 μm or more are 50 / mm 3 The number of particles of the spherical silica composition containing pores with a diameter of 10㎛ or more is 5 / mm or less. 3 Spherical silica composition of the following type. Claim 6 In claim 1, the spherical silica composition contains 100 ppm or more of crystalline silica. Claim 7 A spherical silica composition according to claim 1, wherein the uranium element content in the spherical silica composition is 5 ppb or less, and furthermore, the sodium element content in the spherical silica composition is 100 ppb or less. Claim 8 In claim 1, the spherical silica composition comprises a surface treatment of a silane compound. Claim 9 A resin composition characterized by having a spherical silica composition described in claim 1 and a resin material that disperses the spherical silica composition. Claim 10 A slurry composition characterized by having a spherical silica composition described in claim 1 and a dispersion medium for dispersing the spherical silica composition. Claim 11 A filler for a semiconductor package sealant characterized by containing the spherical silica composition described in claim 1. Claim 12 A method for analyzing pores in a spherical silica composition, characterized by comprising: a dispersion process for dispersing a spherical silica composition in a resin composition; a cross-sectional analysis process for analyzing a cross-section of the spherical silica composition together with the resin composition using X-ray CT or FIB-SEM; and a pore calculation process for preparing a three-dimensional image from the cross-sectional analysis and calculating the diameter and volume of pores present in the spherical silica composition. Claim 13 A method for analyzing the pores of a spherical silica composition according to claim 12, wherein a curing process for curing the resin composition is provided after the dispersion process.

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