Composite oxide particle materials and their manufacturing methods, fillers, filler-containing slurry compositions, and filler-containing resin compositions.

Abstract

The problem to be solved is to provide a composite oxide particle material made of zinc molybdate with high purity and high sphericity. It is made of a composite oxide of molybdenum and zinc, wherein the average particle size of the molybdenum-zinc composite oxide is 0.1 μm or more and 5.0 μm or less, and the BET specific surface area is 1 m². 2 / g or more and 20 m The XRD intensity is 2 g or less, (26.6° peak intensity in XRD) / (24.2° peak intensity) is 1.20 or more, the impurity concentration is 1% by mass or less, and the roundness is 0.90 or more. XRD is measured by CuKα rays.

Description

Technical Field

[0001] This invention relates to composite oxide particle materials containing molybdenum and zinc, their manufacturing methods, fillers, filler-containing slurry compositions, and filler-containing resin compositions. Prior Technology

[0002] With the advancement of high-frequency and high-speed semiconductor devices, it is necessary to reduce the dielectric constant / dielectric loss tangent of the materials constituting semiconductor devices.

[0003] For example, silicon oxide or aluminum oxide are mainly used as fillers in semiconductor devices, but zinc molybdate can be used in conjunction for flame retardant purposes or to improve processability. However, due to the high dielectric constant / dielectric loss tangent of zinc molybdate, it must be suppressed to an even lower level.

[0004] As methods for producing zinc molybdate, there are known methods that synthesize it by reacting a mixture of sodium molybdate aqueous solution and zinc chloride, or by reacting molybdenum oxide and zinc oxide in water by heating.

[0005] Therefore, spherical particles are suitable if filling properties are considered, but zinc molybdate produced by wet synthesis has low sphericity. The method of oxidizing metal particles in a high-temperature oxidizing gas environment (VMC method) is suitable for manufacturing spherical particle materials, and a method for manufacturing zinc molybdate has also been disclosed (Patent Document 1).

[0006] Patent Documents Patent Document 1: Japanese Patent Publication No. 2005-082668 Summary of the Invention

[0007] However, the method in Patent Document 1 contains a large amount of unreacted raw materials or byproducts (molybdenum oxide, zinc oxide), which is not applicable in practical use.

[0008] The present invention was made in view of the above-mentioned facts, aiming to solve the problem of providing a composite oxide particle material made of zinc molybdate with high purity and high sphericity, and a method for manufacturing the same. Further, it aims to solve the problem of providing fillers containing such composite oxide particle materials, filler-containing slurry compositions, and filler-containing resin compositions.

[0009] The inventors, through dedicated research aimed at solving the aforementioned problems, discovered that for zinc molybdate, a crystalline structure exhibiting an XRD peak intensity ratio of 26.6° / 24.2° of 1.20 or higher can reduce the dielectric constant or dielectric loss tangent. They found that using the VMC method to achieve this crystalline structure and increasing the amount of oxygen supplied to the reaction is indeed effective. Furthermore, they discovered that by improving the VMC method, not only can the XRD peak intensity ratio of 26.6° / 24.2° be made 1.20 or higher, but the amount of unreacted substances or byproducts can also be reduced, thus completing this invention.

[0010] That is, the composite oxide particle material of the present invention, which solves the above problems, is made of a composite oxide of molybdenum and zinc with an average particle size of 0.1 μm or more and 5.0 μm or less, a BET specific surface area of ​​1 m² / g or more and 20 m² / g or less, a ratio of (26.6° peak intensity in XRD) / (24.2° peak intensity) of 1.20 or more, an impurity concentration of 1% by mass or less, and a roundness of 0.90 or more. XRD is measured by CuKα rays.

[0011] Furthermore, a relative permittivity of 16 or less is preferred. Also, the ratio of (dielectric loss tangent) to (BET specific surface area (m²)) is preferably 0.0030 or less. Further surface treatment with an organosilicone compound is also preferred.

[0012] The method for manufacturing composite oxide particle material of the present invention, which solves the above problems, is a method for manufacturing composite oxide particle material of the present invention, comprising: a raw material particle material preparation step for preparing raw material particle material comprising one or more kinds of metallic molybdenum and metallic zinc, and a composite oxide particle material manufacturing step for continuously placing the aforementioned raw material particle material dispersed in a carrier into a flame in an oxidizing gas environment for combustion to manufacture composite oxide particle material.

[0013] In particular, the ratio (R / T) of the amount of oxygen T required to completely oxidize the aforementioned raw material particles and combustible gas per unit time to the amount of oxygen R introduced into the aforementioned oxidizing gas environment per unit time is preferably 1.2 or higher.

[0014] The filler of the present invention, which solves the above problems, is used in resin compositions for electronic materials containing the composite oxide particle material of the present invention. In particular, it may also contain other inorganic particle materials.

[0015] The filler-containing slurry composition of the present invention, which solves the above problems, has the filler of the present invention and a dispersion medium for dispersing the aforementioned filler.

[0016] The filler-containing resin composition of the present invention, which solves the above problems, has the filler of the present invention and a resin material for dispersing the aforementioned filler.

[0017] The composite oxide particle material of the present invention, by having the above-mentioned constituent elements, makes it possible to provide a composite oxide particle material made of zinc molybdate with low dielectric constant / dielectric loss tangent, good electrical properties and few impurities. Simple Explanation of the Diagram

[0018] Figure 1 shows the XRD patterns of the test specimens of each embodiment and comparative example.

[0019] Figure 2 shows the IR spectrum of Example 8. Implementation

[0020] The composite oxide particle material and its manufacturing method of the present invention will be described in detail according to the following embodiments. The composite oxide particle material of this embodiment is a particle material made of zinc molybdate, a composite oxide of molybdenum and zinc, and can be used as part to all of the filler contained in resin compositions used as sealants, primers, substrate materials, etc., in semiconductors. When used in combination with other materials, it can be used with silicon oxide particle materials, alumina particle materials, etc.

[0021] (Composite oxide particle materials)

[0022] The composite particle material of this embodiment is made of zinc molybdate, and the impurity content is less than 1% by mass. The so-called impurities refer to unreacted metallic molybdenum and metallic zinc, as well as molybdenum oxide and zinc oxide generated by the oxidation of molybdenum and zinc alone. The amount of impurities is calculated based on a standard curve obtained by XRD measurement of powders with varying mixing ratios of zinc molybdate, molybdenum oxide, zinc oxide, molybdenum, and zinc.

[0023] The composite oxide particle material of this embodiment has a crystalline structure with a peak intensity of (26.6° XRD) / (24.2°) of 1.20 or higher. Examples of its lower limit values ​​are: 1.22, 1.24, 1.26, 1.28, and 1.30.

[0024] As a method for calculating peak intensity from XRD patterns, the baseline is set as a straight line connecting the intensity at a diffraction angle of 18° and the intensity at a diffraction angle of 45°, and the heights at positions of 26.6° and 24.2° are defined as their respective peak intensities.

[0025] The composite oxide particle material of this embodiment has an average particle size of 0.1 μm or more and 5.0 μm or less. Examples of lower limits include 0.15 μm, 0.20 μm, 0.25 μm, and 0.30 μm, while examples of upper limits include 4.5 μm, 4.0 μm, 3.5 μm, and 3.0 μm. These lower and upper limits can be combined arbitrarily. The average particle size in this specification is the equivalent circle diameter. Specifically, it is the average value measured using image processing software (Asahi Kasei Engineering Co., Ltd.: A-Image).

[0026] The roundness of the composite oxide particle material in this embodiment is 0.90 or higher, with examples of lower limits: 0.95, 0.98, 0.99, and 1.00. Roundness is calculated using SEM photographs, where the area and perimeter of the observed particles are measured as a value calculated from (roundness) = [4π × (area) ÷ (perimeter) 2]. The closer to 1, the closer to a perfect sphere. Specifically, the average value is obtained by measuring more than 100 particles using image processing software (Asahi Kasei Engineering Co., Ltd.: A-Image).

[0027] The composite oxide particle material of this embodiment has a BET specific surface area, measured using nitrogen, that is 1 m² / g or more and 20 m² / g or less. Examples of lower limits are: 1.5 m² / g, 2.0 m² / g, and 2.5 m² / g, and examples of upper limits are: 18 m² / g, 16 m² / g, and 14 m² / g. These lower and upper limits can be combined arbitrarily.

[0028] The relative permittivity of the composite oxide particle material of this embodiment is preferably below 16, with upper limits such as 15.8, 15.5, 15.3, and 15.0. Commercially available zinc molybdate or zinc molybdate synthesized by wet synthesis exhibits a relative permittivity exceeding 16 but below approximately 18.

[0029] The lower the value of dielectric loss tangent (Df), the better. For example, Df / (BET specific surface area) is preferably below 0.0030. The upper limit values ​​can be 0.0028, 0.0026, 0.0024, 0.0022, and 0.0020.

[0030] The composite oxide particle material of this embodiment is preferably surface-treated with an organosilicone compound. The organosilicone compound is preferably a silane compound or a silazane compound; examples of silane compounds include those with phenyl, alkyl, vinyl, methacrylic, epoxy, phenylamino, amino, and styryl groups. Since the OH groups present on the surface frequently react, the residual amount of OH groups is preferably 2 or less per nm², and more preferably 1 or less per nm².

[0031] (Manufacturing method of composite oxide particle materials)

[0032] The method for manufacturing composite oxide particle materials of this embodiment is a suitable method for manufacturing composite oxide particle materials of this embodiment. Specifically, it includes a raw material particle material preparation step, a composite oxide particle material manufacturing step, and other steps selected according to requirements.

[0033] The raw material particle material preparation process is a process for preparing raw material particle materials that contain one or more types of metallic molybdenum and metallic zinc.

[0034] The prepared raw material particles can be composed of a single material or two or more particle materials with different compositions. The term "raw material particles containing molybdenum and zinc" means that if the raw material particles composed of one or more particle materials are analyzed, they contain both molybdenum and zinc. For example, it can be a mixture of particle materials composed of molybdenum and zinc, or an alloy of molybdenum and zinc. In particular, the raw material particles are preferably those containing molybdenum and zinc with high purity. The raw material particles can also be surface-treated using the previously described organosilicon compounds. Surface treatment can improve the dispersion state in the carrier described later or prevent aggregation.

[0035] The particle size of the raw material particles varies depending on the particle size of the composite oxide particles being manufactured, but it can be made to be around 1 μm to 30 μm. It is preferable to reduce the particle size of the raw material particles to make them easier to carry out oxidation reactions, but if the particle size is too small, there is a tendency for the supply to deteriorate.

[0036] The preparation method of the raw material particles is not particularly limited. For example, metallic molybdenum or metallic zinc can be particled by atomization, pulverization, etc. In particular, the method using a disc sprayer is preferred.

[0037] The composite oxide particle material preparation process involves placing raw material particles in a flame under an oxidizing gas environment to produce composite oxide particles. By setting the placement conditions of the raw material particles or the generation conditions of the flame to have the same average particle size, BET specific surface area, or XRD pattern as the composite oxide particles of this embodiment described above, not only can the residue of unreacted substances be suppressed, but the amount of by-products can also be reduced, thereby reducing the relative permittivity / dielectric loss tangent of the obtained composite oxide particle material.

[0038] Regarding the obtained composite oxide particle material, to increase the average particle size, this can be achieved by increasing the concentration of raw materials in the oxidizing gas environment. Conversely, to decrease the average particle size, this can be achieved by decreasing the concentration of raw materials in the oxidizing gas environment. In particular, by increasing the amount of oxygen introduced into the oxidizing gas environment described below beyond the theoretically required amount, excellent composite oxide particle materials can be manufactured.

[0039] The raw material particles are placed in a flame while dispersed in a carrier. Examples of carriers include gases and liquids. Examples of gases include air, nitrogen, oxygen, and argon. Examples of liquids include water and alcohols such as isopropanol.

[0040] When the raw material particles are placed into the flame, oxygen is simultaneously introduced into the oxidizing gas environment. The introduction of oxygen into the oxidizing gas environment can be done by partially or entirely filling the carrier with oxygen, or by introducing oxygen through a separate gas flow from the carrier. In addition to introducing oxygen alone, oxygen can be introduced together with nitrogen (including in the case of introducing air) or other inert gases. It is preferable to create the oxidizing gas environment within a partially enclosed furnace, as this allows for precise control of the amount of oxygen introduced and the flame temperature.

[0041] The ratio (R / T) of the theoretically required amount of oxygen (T) for the complete oxidation of raw material particles and combustible gases introduced into the flame per unit time to the actual amount of oxygen introduced into the oxidizing gas environment per unit time is preferably 1.2 or higher. By setting an amount that is sufficiently excessive than the theoretically required amount of oxygen, a crystalline structure with a peak intensity of 26.6° XRD and a peak intensity of 24.2° of 1.20 or higher can be formed. This can further suppress the residue of unreacted substances and even reduce the amount of by-products.

[0042] The obtained composite oxide particle material can be subjected to the surface treatment described above for the composite oxide particle material of this embodiment. The surface treatment can be performed by: bringing a surface treatment agent into contact with the surface of the composite oxide particle material; or bringing the surface treatment agent into contact with the surface of the composite oxide particle material while the surface treatment agent is dissolved or dispersed in a suitable solvent (isopropanol, methyl ethyl ketone (MEK), or other solvent capable of dispersing the composite oxide particle material); or bringing the surface treatment agent into contact with the surface of the composite oxide particle material while the surface treatment agent is vaporized. Heating or other methods can also be applied after contact to promote the reaction of the surface treatment agent.

[0043] The surface treatment dosage is not particularly limited, but can be selected from any amount ranging from less than or exceeding the amount of OH groups on the surface of the composite oxide particle material immediately after the composite oxide particle material preparation process.

[0044] Examples of lower limits for the amount of organosilicone compound per unit surface area (m²) calculated using the BET specific surface area after surface treatment as a surface treatment agent include: 0.2 μmol / m², 0.3 μmol / m², and 0.4 μmol / m². Examples of upper limits include: 20 μmol / m², 18 μmol / m², and 16 μmol / m². These lower and upper limits can be combined arbitrarily.

[0045] (fillers, filler-containing slurries, filler-containing resin compositions)

[0046] The filler of this embodiment is used in resin compositions for electronic materials and has the composite oxide particle material of the aforementioned embodiment. Inorganic particle materials may also be further included as needed. Examples of inorganic particle materials include silicon oxide particle materials and alumina particle materials. The resin composition for electronic materials can be used in sealants, primers, and substrate materials for semiconductor devices.

[0047] The filler-containing slurry of this embodiment is a slurry in which the filler is dispersed in a dispersion medium. The dispersion medium is not particularly limited except that it is a liquid, and examples include: organic solvents such as MEK, resin precursors (monomers, prepolymers, etc.). The proportion of the filler is not particularly limited, but it is preferable to increase it within the range that can maintain the fluidity of the slurry.

[0048] The filler-containing resin composition of this embodiment is a composition in which the filler is dispersed in a resin material. The resin material is not particularly limited; it can be liquid or solid.

[0049] The types of resin materials that can be used are not particularly limited; common resin materials such as thermoplastic resins and thermosetting resins can be selected. Examples include: epoxy resin, polyimide, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polymethyl methacrylate, polyvinyl chloride, polypropylene, polyethylene, and polyphenylene ether.

[0050] The method for dispersing particulate material in resin material is not particularly limited. For example, when using a thermoplastic resin as the resin material, the resin material is mixed with the particulate material after heating and melting to form a compound, or a resin precursor is mixed with the particulate material and then subjected to a polymerization reaction to obtain a resin composition. When the resin material is a thermosetting resin, the resin precursor is mixed with the particulate material and then cured. Furthermore, using a liquid resin precursor as the composition of the resin material is also a filler-containing resin composition of this embodiment.

[0051] Example

[0052] The composite oxide particle material of the present invention will be described in detail based on the following embodiments.

[0053] <Preparation of Test Specimens>

[0054] • Examples 1-7 and Comparative Example 1 (manufactured via VMC method)

[0055] Molybdenum powder with an average particle size of 3 μm and a purity of 99.9% or higher is mixed with zinc powder with an average particle size of 30 μm and a purity of 99% or higher in a molar ratio of 1:1 to prepare raw material particle material (raw material particle material preparation process).

[0056] The raw material particles were placed in an oxidizing flame within an oxidizing gas environment formed in the reactor. The raw material particles were dispersed in the air, which served as a carrier, at a concentration of 4 kg / m³ and then placed in the furnace for combustion to obtain a composite oxide particle material (zinc molybdate) of molybdenum and zinc, which was used as the test sample in this embodiment (composite oxide particle material preparation process).

[0057] At this point, air is introduced into the reactor in such a way that the ratio (R / T) of the amount of oxygen required for the complete oxidation of the raw material particles and combustible gas (theoretical O2 amount T) to the actual amount of oxygen introduced (introduced O2 amount R) is as shown in Table 1.

[0058] Example 8

[0059] The test specimen obtained in Example 3 was surface-treated with phenylaminosilane (KBM-573) as a surface treatment agent to obtain the test specimen of this example. The surface treatment amount was 10 μmol per unit surface area (m²) as measured by BET surface area. The surface treatment was confirmed by IR spectroscopy. Specifically, the presence of a peak of CH stretching vibration of phenylaminosilane near 2940 cm⁻¹ was confirmed, thereby confirming that phenylaminosilane is bonded to the surface. An example of the IR spectrum is shown in Figure 2.

[0060] Example 9

[0061] Except for using the test specimen of Example 4 instead of the test specimen of Example 3, the same operation as in Example 8 was performed to obtain the test specimen of this example.

[0062] Example 10

[0063] Except for using vinyl silane (KBM-1003) instead of phenylamino silane as the surface treatment agent, the same operation as in Example 8 was performed to obtain the test sample of this example.

[0064] Example 11

[0065] Except for using methacrylic silane (KBM-503) instead of phenylamino silane as the surface treatment agent, the same operation as in Example 8 was performed to obtain the test sample of this example.

[0066] Comparative Example 2

[0067] The commercially available reagent (manufactured by Mitsuwa Chemicals Co., Ltd.) was designated as the test sample for this comparative example.

[0068] Comparative Example 3

[0069] A composite oxide particle material was prepared by a wet synthesis method and designated as the test sample for this comparative example. Specifically, the synthesis operation was carried out as follows: First, 10.3 g of molybdenum oxide (manufactured by KISHIDA CHEMICAL CO., LTD.) was added to 500 g of deionized water, and the mixture was heated / stirred at 80°C. Then, 5.8 g of zinc oxide (manufactured by KISHIDA CHEMICAL CO., LTD.) was added, and the mixture was stirred for 4 hours. Afterward, the solid and liquid components were separated, the solid components were dried, and calcined at 550°C for 8 hours to obtain the composite oxide particle material made of zinc molybdate.

[0070] <evaluate>

[0071] The equivalent circle diameter, specific surface area, roundness, amount of unreacted material and byproducts, relative permittivity, dielectric loss tangent, dielectric loss tangent / specific surface area, (peak intensity at 26.6° in XRD) / (peak intensity at 24.2°), and amount of O2 added / theoretical amount of O2 were measured and calculated separately. The results are shown in Table 1. The XRD patterns of the test specimens of each embodiment and comparative example are shown in Figure 1 for reference.

[0072] • Relative permittivity, dielectric loss tangent

[0073] The relative permittivity at 1 GHz was measured using a network analyzer (KEYSIGHT E5071C) and the cavity resonator perturbation method. This measurement was performed in accordance with ASTM D2520 (JIS C2565).

[0074] • Amount of unreacted substances and byproducts

[0075] Mixed powders with varying blending ratios of zinc molybdate, molybdenum oxide, zinc oxide, metallic molybdenum, and metallic zinc were subjected to XRD analysis. The diffraction intensity at the diffraction angle (2θ) of each substance was read from the obtained graphs, and a standard curve was plotted. The content of unreacted substances and byproducts in the test samples of each example and comparative example was calculated using the plotted standard curves.

[0076] Zinc molybdate uses the peak value near 27°, molybdenum oxide uses the peak value near 23°, zinc oxide uses the peak value near 32°, metallic molybdenum uses the peak value near 40°, and metallic zinc uses the peak value near 43°.

[0077] Table 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 Comparative Example 1 Comparative Example 2 Comparative Example 3 Equivalent circle diameter (μm) 0.6 0.6 0.7 0.4 0.4 0.6 0.9 0.7 0.4 0.7 0.7 0.8 31.6 1.2 Specific surface area (m² / g) 3.4 3.1 3.1 6.7 6.0 4.8 3.3 3.1 6.7 3.1 3.1 3.3 0.8 3.7 Roundness 0.97 0.98 0.98 0.98 0.97 0.99 0.98 0.98 0.98 0.98 0.98 0.98 0.10 0.51 Unreacted + Byproducts (%) 0.4 0.2 0.1 0.2 0.3 0.0 0.2 0.1 0.2 0.1 0.1 5.6 — — Relative permittivity 12.7 12.7 12.6 13.5 14.2 12.9 13.6 14.4 14.8 14.3 14.5 14.8 16.1 17.3 Dielectric loss tangent 0.0044 0.0042 0.0037 0.0069 0.0070 0.0049 0.0041 0.0032 0.0036 0.0028 0.0036 0.0068 0.0027 0.0117 Dielectric loss tangent / specific surface area 0.0013 0.0013 0.0012 0.0010 0.0012 0.0010 0.0012 0.0010 0.0005 0.0009 0.0012 0.0021 0.0034 0.0032 Peak intensity at 26.6° / Peak intensity at 24.2° 1.41 1.39 1.36 1.39 1.35 1.54 1.48 1.36 1.39 1.36 1.36 1.44 1.05 1.05 Add O2 amount / Theoretical O2 quantity 1.5 1.7 1.8 1.4 1.5 1.2 1.9 1.8 1.4 1.8 1.8 1.1 — —

[0078] As shown in the table, the test samples of Examples 1-11 and Comparative Example 1, manufactured by the VMC method, have high roundness. Furthermore, it is evident that Examples 1-11 have high purity (low amounts of unreacted substances and byproducts).

[0079] Furthermore, it can be seen that Examples 1 to 11 and Comparative Example 1, in which the ratio of (peak intensity at 26.6° of XRD) to (peak intensity at 24.2°) is 1.20 or higher, have test specimens with a relative permittivity of 16 or less and a dielectric loss tangent / specific surface area of ​​0.0030 or less, exhibiting excellent electrical properties.

[0080] It can be seen that Examples 1-11, where the O2 content / theoretical O2 content ratio is 1.2 or higher, have significantly less unreacted material and byproducts compared to Comparative Example 1, which has a lower ratio of 1.1. The dielectric loss tangent / specific surface area ratio is also smaller. While there is a possibility of an error of approximately 0.1-0.2% in the amount of unreacted material and byproducts, the 5.6% value of Comparative Example 1 is significantly larger than that of Examples 1-11. The test specimens of Comparative Examples 2 and 3 have lower roundness and larger dielectric loss tangent / specific surface area ratios.

[0081] Therefore, it can be seen that if the ratio of (peak intensity at 26.6° in XRD) to (peak intensity at 24.2°) is 1.20 or higher, the electrical properties are excellent and the amount of unreacted substances and byproducts is also low. It is clear that in preparing this type of composite oxide particle material, setting the ratio of the amount of O2 added to the theoretical amount of O2 to 1.2 or higher is effective.

[0082] none.

Claims

1. A composite oxide particle material, which is made from a composite oxide of molybdenum and zinc with an average particle size of 0.1 μm or more and 5.0 μm or less, a BET specific surface area of ​​1 m² / g or more and 20 m² / g or less, an impurity concentration of 1% by mass or less of molybdenum, zinc, molybdenum oxide and / or zinc oxide, and a roundness of 0.90 or more. The aforementioned composite oxide particle material is manufactured by a composite oxide particle material manufacturing process in which the raw material particle material is continuously placed in a flame in an oxidizing gas environment and burned to manufacture the aforementioned composite oxide particle material. The ratio (R / T) of the amount of oxygen T required to completely oxidize the aforementioned raw material particle material and combustible gas per unit time to the amount of oxygen R introduced into the aforementioned oxidizing gas environment per unit time is 1.2 or more.

2. The composite oxide particle material as described in claim 1, wherein the relative permittivity is 16 or less.

3. The composite oxide particle material as described in claim 1, wherein the ratio of dielectric loss tangent to BET specific surface area (m2) is 0.0030 or less.

4. The composite oxide particle material as described in claim 1, wherein the ratio of (peak intensity at 26.6° of XRD) to (peak intensity at 24.2°) is 1.20 or higher.

5. The composite oxide particle material as described in claim 1, which is surface-treated with an organosilicon compound.

6. A method for manufacturing a composite oxide particle material, comprising: a raw material preparation step for preparing raw material particles comprising one or more metals, namely molybdenum and zinc; and a composite oxide particle material manufacturing step for continuously igniting the aforementioned raw material particles in a flame in an oxidizing gas environment to produce the composite oxide particle material, wherein the ratio (R / T) of the amount of oxygen T required to completely oxidize the aforementioned raw material particles and the combustible gas to the amount of oxygen R introduced into the aforementioned oxidizing gas environment is 1.2 or more.

7. A filler for use in resin compositions for electronic materials having composite oxide particle materials as described in any one of claims 1 to 5.

8. The filler as described in claim 7, which contains other inorganic particle materials.

9. A filler-containing slurry composition having the filler as described in claim 7 or 8, and a dispersion medium for dispersing the aforementioned filler.

10. A filler-containing resin composition having the filler as described in claim 7 or 8, and a resin material dispersing the aforementioned filler.

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