Oxide powder

Abstract

Disclosed is an oxide powder which contains at least one element that is selected from the group consisting of Cu, Zn, V, Mg, P, and S. The oxide powder has a sphericity of 0.7 to 1.0 inclusive, and has a temperature range in which at least the dimensional change ratio (∆L / L) is less than 0 in a temperature range of 0°C to 200°C inclusive, or a temperature range in which at least the linear expansion coefficient (α) is less than 0 ppm / K in a temperature range of 0°C to 200°C inclusive. The sphericity of the oxide powder may be preferably 0.8 to 1.0 inclusive. The oxide powder can be produced by a method that includes subjecting a starting material powder to a spheroidizing treatment by flame melting or PVD.

Description

Oxide powder

[0001] The present invention relates to a novel oxide powder having a spherical particle shape. The present invention also relates to a resin composition and a powder mixture containing the spherical oxide powder. Further, the present invention relates to a method for producing the spherical oxide powder.

[0002] In recent years, in technical fields that require high precision such as highly developed electronic devices, optical devices, fuel cells, and sensors, control and suppression of thermal expansion of solid materials have been strongly demanded. In particular, when constructing precision devices such as semiconductor devices that require high precision at the nanometer level by combining multiple materials, if positional deviation, interfacial peeling, disconnection, warping, cracks, etc. occur due to the difference in the coefficient of thermal expansion between the materials, it may become a serious problem. Therefore, a technology for highly controlling thermal expansion is required.

[0003] While many substances thermally expand as the temperature rises, it is also known that there are rare negative thermal expansion materials having a negative coefficient of thermal expansion with the property that the volume decreases as the temperature rises. As one of the technologies for controlling the thermal expansion of precision devices, for example, a technology for controlling the coefficient of thermal expansion of the entire device by adding a negative thermal expansion material in combination with a matrix material (resin, glass, metal, etc.) having a large positive coefficient of thermal expansion and a material (e.g., silica) having a low positive coefficient of thermal expansion as needed has attracted attention. Examples of negative thermal expansion materials include, for example, β-eucryptite, zirconium tungstate (ZrW ２ O ８ ), zirconium tungsten phosphate (Zr ２ WO ４ (PO ４ ) ２ ), Zn ｘ Cd １－ｘ (CN ２ ), manganese nitride, bismuth nickel ferrite, etc. are known.

[0004] For example, in Patent Document 1, zirconium oxide ZrO ３ with respect to tungsten trioxide WO ２The negative thermal expansion material Zr is characterized by mixing raw materials in a stoichiometric ratio such that the sum of the substitution element X with the substitution amount x is 1 molar ratio, forming a powder with a polarized particle size distribution consisting of small particles with a predetermined particle size range and large particles with a predetermined particle size range, and then placing the raw material powder into a desired mold and sintering it. （１－ｘ） X ｘ W ２ O ８ A method for synthesizing (where X is a substitution element for zirconium Zr, 0 ≤ x << 1) has been reported. Patent Document 1 states that this synthesis method has the effect of synthesizing large, high-density heat-shrinkable ceramics without press molding of the raw material powder. In addition to Patent Document 1, development is underway on new negative thermal expansion materials with various compositions and properties, as well as methods for manufacturing them.

[0005] Japanese Patent Publication No. 2003-342075

[0006] For example, in precision equipment such as semiconductor devices that require high-precision thermal expansion control, the actual operating temperature during the heat cycle of the equipment is often below 150°C. Therefore, there is a need for materials that exhibit negative thermal expansion characteristics in such temperature ranges. However, many conventional negative thermal expansion materials only exhibit negative thermal expansion characteristics when they reach temperatures above 150°C. Consequently, research is ongoing to find specific compositions of negative thermal expansion materials that exhibit negative thermal expansion characteristics in lower temperature ranges, such as below 150°C, and preferably achieve a higher thermal contraction rate (i.e., a lower negative thermal expansion rate).

[0007] Furthermore, as described above, negative thermal expansion materials can be used in mixture with matrix materials (resins, glass, metals, etc.). When negative thermal expansion materials are used in precision equipment such as semiconductor devices, it is preferable to suppress the increase in viscosity of the resin composition containing the negative thermal expansion material and matrix resin, and to have high fluidity, from the viewpoint of the moldability of the semiconductor device. However, unfortunately, because negative thermal expansion materials have an angular shape (i.e., low particle sphericity), the viscosity of the resin composition can increase, and the fluidity can decrease significantly. Therefore, there is a need to provide a negative thermal expansion material that has high sphericity and does not cause a decrease in fluidity or an increase in viscosity of the resin composition even when mixed with a matrix resin.

[0008] Therefore, the object of the present invention is to provide a novel oxide powder with high sphericity.

[0009] As a result of diligent research, the inventors have succeeded in developing a novel oxide powder that contains specific elements, possesses negative thermal expansion properties, and has a high degree of sphericity within a specific range. Furthermore, the inventors have found that by applying a specific treatment to oxide powder, which is a negative thermal expansion material, the degree of sphericity of the powder can be improved while maintaining its negative thermal expansion properties. In addition, they have found that by applying a specific treatment to the raw material of the oxide powder, an oxide powder with high degree of sphericity (negative thermal expansion material) can be obtained, thus completing the oxide powder of the present invention.

[0010] In other words, various aspects and embodiments of the present invention can be summarized as follows: [1] An oxide powder comprising at least one element selected from the group consisting of Cu, Zn, V, Mg, P, and S, wherein the sphericity of the oxide powder is 0.7 or more and 1.0 or less, and the dimensional change ratio (ΔL / L) in a temperature range of at least 0°C to 200°C is less than 0, or the coefficient of linear expansion (α) in a temperature range of at least 0°C to 200°C is less than 0 ppm / K. [2] The oxide powder according to [1] comprising at least two or more elements selected from the group consisting of Cu, Zn, V, Mg, P, and S. [3] The oxide powder according to [2] comprising Zn, Mg, and P. [4] General formula (1) Zn ２－ｘ Mg ｘ P ２ O ７±δ [1] A powder comprising at least one oxide represented by the formula (wherein part or all of Mg may be substituted with Sr and / or Ca and / or Ba, where 0 ≤ x ≤ 2 and δ is a value determined to satisfy the charge neutrality condition). [5] A powder according to any one of [1] to [4], wherein the sphericity of the oxide powder is 0.8 or more and 1.0 or less. [6] A resin composition comprising the oxide powder according to any one of [1] to [5] and a resin component. [7] A resin composition according to [6], further comprising a curing agent. [8] An α dose of 0.0200 cph / cm² ２The resin composition according to [6] or [7], which is as follows: [9] A powder mixture comprising the oxide powder and silica-containing powder or other thermally conductive powder according to any one of [1] to [5].

[10] A method for producing oxide powder according to any one of [1] to [5], comprising: step (a): providing raw material powder for spheroidization treatment; and step (b): performing flame melting or PVD spheroidization treatment on the raw material powder obtained in step (a) to obtain oxide powder having a spheroidity of 0.7 or more and 1.0 or less, wherein step (a) comprises any of the following (i) to (iii): (i) providing a mixed powder of raw material powder for spheroidization treatment by mixing a raw material compound containing the constituent elements of oxide powder and a binder; (ii) providing a dried powder of raw material powder for spheroidization treatment by mixing a solution containing a raw material compound containing the constituent elements of oxide powder, allowing it to precipitate, and drying the precipitate; or (iii) providing an oxide powder of raw material powder for spheroidization treatment by calcining a mixture of raw material compounds containing the constituent elements of oxide powder at least once.

[11] The method according to

[10] , wherein the flame melting or PVD in step (b) is performed in a temperature range above the melting point of the raw material powder.

[12] The manufacturing method according to

[10] or

[11] , further comprising the step of performing an annealing treatment in a temperature range of 100°C to 900°C after step (b).

[0011] The present invention provides a novel oxide powder containing specific elements, possessing negative thermal expansion properties, and having a high degree of sphericity within a specific range. Furthermore, the present invention provides a novel method for producing an oxide powder having a high degree of sphericity within a specific range by simple means without requiring complex processes. When the oxide powder of the present invention is mixed with a matrix resin to form a resin composition, the fluidity of the resin composition is improved compared to conventional resin compositions containing negative thermal expansion materials, and the increase in viscosity associated with the mixing of negative thermal expansion materials can be suppressed. In addition, the increase in viscosity associated with an increase in the amount of negative thermal expansion material mixed can be suppressed. As a result, for example, yield can be improved in the manufacturing of semiconductor devices and the like.

[0012] Figure 1 is an SEM image of oxide powder 1 obtained in Example 1. Figure 2 is an SEM image of oxide powder 3 obtained in Example 3. Figure 3 is an SEM image of the raw material powder of Comparative Example 1. Figure 4 is a graph showing the paste viscosity at different shear rates for the examples and comparative examples.

[0013] <Oxide Powder> The oxide powder of the present invention is an oxide powder containing at least one element selected from the group consisting of Cu, Zn, V, Mg, P, and S, wherein the sphericity of the oxide powder is 0.7 or more and 1.0 or less, and has a temperature range in which the dimensional change ratio (ΔL / L) in a temperature range of at least 0°C to 200°C is less than 0, or has a temperature range in which the coefficient of linear expansion (α) in a temperature range of at least 0°C to 200°C is less than 0 ppm / K.

[0014] At least one element selected from the group consisting of Cu, Zn, V, Mg, P, and S (hereinafter referred to as "element A" for simplicity) contained in the oxide powder may include any combination of two or more of these elements.

[0015] In oxide powders, if element A contains only one element, it may be Cu alone, Zn alone, V alone, Mg alone, P alone, or S alone.

[0016] In oxide powders, if element A includes a combination of two elements, it may be a combination of Cu / Zn, Cu / V, Cu / Mg, Cu / P, Cu / S, Zn / V, Zn / Mg, Zn / P, Zn / S, V / Mg, V / P, V / S, Mg / P, Mg / S, or P / S.

[0017] In oxide powders, if element A includes a combination of three elements, one of the following combinations can be selected: Cu / Zn / V, Cu / Zn / Mg, Cu / Zn / P, Cu / Zn / S, Cu / V / Mg, Cu / V / P, Cu / V / S, Cu / Mg / P, Cu / Mg / S, Cu / P / S, Zn / V / Mg, Zn / V / P, Zn / V / S, Zn / Mg / P, Zn / Mg / S, Zn / P / S, V / Mg / P, V / Mg / S, V / P / S, or Mg / P / S.

[0018] In an oxide powder according to a preferred embodiment, element A may include Zn, Mg, and P as a combination of three elements. It is more preferable that element A consists of Zn, Mg, and P.

[0019] In oxide powders, if element A includes a combination of four elements, one of the following combinations can be selected: Cu / Zn / V / Mg, Cu / Zn / V / P, Cu / Zn / V / S, Cu / Zn / Mg / P, Cu / Zn / Mg / S, Cu / Zn / P / S, Cu / V / Mg / P, Cu / V / Mg / S, Cu / V / P / S, Cu / Mg / P / S, Zn / V / Mg / P, Zn / V / Mg / S, Zn / V / P / S, Zn / Mg / P / S, or V / Mg / P / S.

[0020] In oxide powders, if element A includes a combination of five elements, one of the following combinations can be selected: Cu / Zn / V / Mg / P, Cu / Zn / V / Mg / S, Cu / Zn / V / P / S, Cu / Zn / Mg / P / S, Cu / V / Mg / P / S, or Zn / V / Mg / P / S.

[0021] Oxide powders include, for example, those with the general formula: Zn ２－ｘ Tｘ P ２－ｙ A ｙ O ７±δ The material may contain at least one powder of an oxide represented by (T is at least one element selected from Mg, Ca, Al, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, La, Ta, W, and Bi; A is at least one element selected from Al, Si, V, Ge, and Sn, satisfying 0 ≤ x < 2 and 0 ≤ y ≤ 2; and δ is a value determined to satisfy the charge neutrality condition, excluding (x, y) = (0, 0) and (0, 2).). In this specification, the "charge neutrality condition" does not have to be completely neutral, and compositions with oxygen deficiencies or excesses within an acceptable range for the compound may be included.

[0022] In one preferred embodiment, the oxide powder is Zn of general formula (1). ２－ｘ Mg ｘ P ２ O ７±δ The formula may contain at least one powder of an oxide represented by the above general formula (1) Zn (wherein part or all of Mg may be substituted with Sr and / or Ca and / or Ba, where 0 ≤ x ≤ 2 and δ is a value determined to satisfy the charge neutrality condition). From the viewpoint of further reducing the thermal expansion coefficient of the oxide powder, the above general formula (1) Zn ２－ｘ Mg ｘ P ２ O ７±δ In the formula, it is preferable that 0.05 ≤ x ≤ 0.5.

[0023] Oxide powders include, for example, those with the general formula: Cu ２－ｘ R ｘ V ２－ｙ P ｙ O ７±δ The material may contain at least one powder of an oxide represented by (R, which includes at least one element selected from Mg, Al, Si, Ti, Cr, Mn, Fe, Co, Ni, Zn, and Sn, satisfying 0 ≤ x ≤ 2 and 0 < y < 2, and δ is a value determined to satisfy the charge neutrality condition).

[0024] Oxide powders, for example, have Al atoms in solid solution, and their general formula is Cuｘ M ｙ V ｚ O ｔ±δ The material may contain at least one powder of an oxide represented by the formula (wherein M represents a metallic element with an atomic number of 11 or higher other than Cu, V, and Al, preferably one or more metallic elements selected from Zn, Ga, Fe, Mg, Co, Mn, Ba, and Ca. x represents 1.60 ≤ x ≤ 2.40, y represents 0.00 ≤ y ≤ 0.40, z represents 1.70 ≤ z ≤ 2.30, t represents 6.00 ≤ t ≤ 9.00, and δ is a value determined to satisfy the charge neutrality condition, provided that 1.00 ≤ x + y ≤ 3.00. Also, when element M is included, the number of moles of Al atoms on an atomic basis > the number of moles of M atoms on an atomic basis.)

[0025] Oxide powders, for example, have a solid solution of Li atoms in a general formula: (Cu ｘ M ｙ ) (V ａ P ｂ ) O ｔ±δ The material may contain at least one powder of an oxide represented by the formula (wherein M represents a metallic element with an atomic number of 11 or higher other than Cu and V, preferably one or more selected from Zn, Ga, Fe, Mg, Co, Mn, Al, Ba, and Ca. x represents 1.60 ≤ x ≤ 2.40, y represents 0.00 ≤ y ≤ 0.40, a represents 1.60 ≤ a ≤ 2.40, b represents 0.00 ≤ b ≤ 0.40, t represents 5.00 ≤ t ≤ 9.00, and δ is a value determined to satisfy the charge neutrality condition, provided that 1.60 ≤ x + y ≤ 2.40 and 1.60 ≤ a + b ≤ 2.40).

[0026] Oxide powders include, for example, those with the general formula: Zr ｘ (WO ４ ) ｙ±δ１ (PO ４ ) ｚ±δ２ The material may contain at least one powder of an oxide represented by the formula (wherein 1.7 ≤ x ≤ 2.3, 0.8 ≤ y ≤ 1.2, 1.7 ≤ z ≤ 2.3, and δ1 and δ2 are values ​​that are independently determined to satisfy the charge neutrality condition).

[0027] Oxide powders include, for example, those with the general formula: Zr ２．００－ｂ M ｂ S Ｙ PＺ O １２．００±δ The product may contain at least one powder of an oxide represented by the formula (wherein M is at least one selected from Ti, Ce, Sn, Mn, Hf, Ir, Pb, Pd, Cr, W, Mo, 0 ≤ b < 2.00, 0 < Y < 0.30, Z ≥ 2.00, and δ is a value determined to satisfy the charge neutrality condition).

[0028] Oxide powders include, for example, those with the general formula: Zr ２．００－ｂ M ｂ S Ｙ P Ｚ O １２．００±δ The product may contain at least one powder of an oxide represented by the formula (wherein M is at least one selected from Ti, Ce, Sn, Mn, Hf, Ir, Pb, Pd, Cr, W, Mo, 0 ≤ b < 2.00, 0.30 ≤ Y ≤ 1.00, Z > 2.00, and δ is a value determined to satisfy the charge neutrality condition).

[0029] Oxide powders include, for example, those with the general formula: Ti ２－ｘ M ｘ O ３±δ The material may contain at least one powder of an oxide represented by (M, which includes at least one element selected from Mg, Al, Si, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, In, Sn, Sb, La, Ta, W, Bi, satisfying 0 ≤ x < 2, and δ is a value determined to satisfy the charge neutrality condition, where M includes at least one element selected from the group consisting of Zn, Cu, Mg, and V).

[0030] The oxide powder has a sphericity of 0.7 or more and 1.0 or less. A sphericity of 0.7 or more improves the fluidity of the resin composition containing the oxide powder and suppresses viscosity increase, thus potentially improving yield in the manufacture of semiconductor devices and the like. The sphericity of the oxide powder is preferably 0.72 or more and 1.0 or less, more preferably 0.74 or more and 1.0 or less, 0.76 or more and 1.0 or less, or 0.78 or more and 1.0 or less. Even more preferably, the sphericity of the oxide powder is 0.8 or more and 1.0 or less, more preferably 0.82 or more and 1.0 or less, 0.84 or more and 1.0 or less, 0.86 or more and 1.0 or less, or 0.88 or more and 1.0 or less.

[0031] In this specification, the sphericity of a powder can be measured by the following method. A sample of oxide powder is observed at a magnification of 2500x using a scanning electron microscope (SU3500, manufactured by Hitachi High-Technologies Corporation) to obtain three SEM images. For each of the three obtained SEM images, image adjustment is performed by binarization of the particles and background. Then, image analysis is performed on each of the 100 particles in the image. Using the image processing software ImageJ, drawing is performed along the particles, and after all drawing is completed, particle analysis is performed to obtain the average area and average circumference of one particle. Then, the sphericity of the powder for one SEM image is calculated using equation (1). The arithmetic mean of the sphericity of the powder obtained from the three images is defined as the sphericity (true sphericity) of the powder in this invention. Sphericity of powder = 4π × (average area of ​​one particle) / (average circumference of one particle) ２ ... (1) While the concept of sphericity or true sphericity of oxide powder (particles) itself, and the fact that the closer the value is to 1, the higher the degree of spherical approximation of the particle shape, have been known for some time, it is considered that raising the sphericity of oxide powder to 0.7 or higher using the calculation method defined above, which is unique to this application, is not known and is not an easy task.

[0032] Oxide powder is a negative thermal expansion material having a negative coefficient of thermal expansion (negative thermal expansion coefficient) which is characterized by its volume decreasing as the temperature rises. Such a negative thermal expansion material may have a temperature range in which the linear expansion coefficient (α: as defined below) is usually less than 0 ppm / K, preferably less than -10 ppm / K, more preferably less than -20 ppm / K, even more preferably less than -30 ppm / K, and even more preferably less than -40 ppm / K. By using such a negative thermal expansion material as an oxide powder, which exhibits a low coefficient of linear expansion within an appropriate temperature range, when a resin composition containing the oxide powder is used as an encapsulating resin for semiconductor devices, the expansion of the encapsulating resin can be reduced, thereby suppressing damage and malfunctions of semiconductor devices and improving yield. Hereafter, the oxide powder that is a negative thermal expansion material may be referred to as "negative thermal expansion powder."

[0033] In this specification, the "coefficient of linear expansion (α)" is defined by the following formula (2): Coefficient of linear expansion (α) [unit ppm / K] = (1 / L) × (ΔL / ΔT) × 10 ６ ... (2) In the formula, L refers to the length of the sample (μm), ΔL refers to the change in sample length (μm) within the specified temperature range, and ΔT refers to the temperature difference (K) within the specified temperature range. In this specification, the "dimensional change ratio," which is the ratio of the change in sample length within the specified temperature range, is defined by the following formula (3): Dimensional change ratio (dimensionless) = ΔL / L ... (3) ΔL and L in the formula are as defined above. The coefficient of linear expansion (α) is expressed in the following relationship with the dimensional change ratio ΔL / L: Coefficient of linear expansion (α) [ppm / K] = {(ΔL / L) / ΔT} × 10 ６

[0034] The oxide powder may, as described above, (i) have a coefficient of linear expansion (α) in any range within the temperature range of -200°C to 500°C, usually within the temperature range of 0°C to 200°C, more preferably in the temperature range of room temperature or higher (e.g., 0°C or higher, 10°C or higher, 20°C or higher, or 30°C or higher) to 150°C or lower, 70°C or lower, or 50°C or lower, which is one of the above-mentioned normal or preferred temperature ranges, or (ii) have a temperature range in which the dimensional change ratio (ΔL / L) is usually less than 0, preferably -2 × 10 －３ It may have a temperature range of the following, more preferably -3 × 10 －３ It may have a temperature range of the following, and more preferably -4 × 10 －３ The temperature range may be as follows, and more preferably -6 × 10 －３ The following temperature range may be observed. In particular, the oxide powder may have a dimensional change ratio (ΔL / L) of -8 × 10 in any range within the temperature range of -200°C to 500°C, preferably within any range within the temperature range of 0°C to 200°C, and more preferably in the temperature range of room temperature or higher (for example, 0°C or higher, 10°C or higher, 20°C or higher or 30°C or higher) to 150°C or lower, 70°C or lower or 50°C or lower. －３ It may have a temperature range of the following, or -10 × 10 －３ The following temperature range may be used. By using an oxide powder that exhibits a low dimensional change ratio within the above appropriate temperature range, when a resin composition containing oxide powder is used as a encapsulating resin for semiconductor devices, the expansion of the encapsulating resin can be reduced, damage and malfunctions of semiconductor devices can be suppressed, and the yield can be improved.

[0035] The dimensional change ratio (ΔL / L: the ratio of length change due to linear expansion) in this specification may be measured by mixing a negative thermal expansion material (powder) with a resin component to form a resin composition. Alternatively, the negative thermal expansion material (powder) may be measured in the state of a compacted molded body (unsintered), or by sintering this compacted molded body. The dimensional change ratio can be measured by a thermomechanical analyzer (TMA), for example, by a Hitachi High-Tech TA7000. When calculating the coefficient of linear expansion (α) using the above formula (2), when substituting values ​​for L to ΔL as described above, the sample length in units of mm displayed on the above device should be set to 10 ３ You can convert it to the unit μm by multiplying by two.

[0036] Two or more types of oxide powders may be mixed. By mixing two or more types of oxide powders that are negative thermal expansion materials, it is possible to create a material that can undergo gradual thermal shrinkage with two or more shrinkage temperature ranges. This makes it possible to suppress the rapid shrinkage of negative thermal expansion materials. For example, a resin composition containing such a mixture of two or more types of oxide powders can reduce the difference in thermal expansion between the resin and the oxide powders in the shrinkage temperature range compared to a resin composition containing only one type of oxide powder.

[0037] Furthermore, in the present invention, the compositional analysis of the obtained sample can be performed using ICP-OES (Inductivity Coupled Plasma Optical Emission Spectrometry) to analyze the composition (atomic ratio). For example, the "Agilient 5110" (manufactured by Agilient Technologies) can be used as the ICP-OES instrument.

[0038] The sphericity of the oxide powder may be, in particular, 0.8 to 1.0 within the range described above. The sphericity of the powder may be 0.82 to 1.0, 0.84 to 1.0, 0.86 to 1.0, or 0.88 to 1.0. The closer the sphericity of the powder is to 1.0, the closer it is to a perfect sphere. By having the sphericity of the powder within the above range, the fluidity of the resin composition containing the oxide powder is further improved and the viscosity increase is suppressed, which can further improve the yield in the manufacture of semiconductor devices and the like.

[0039] The average particle size of oxide powder is determined by the cumulative particle size D at 50% cumulative volume, as measured by laser diffraction scattering particle size distribution analysis, from the perspective of the dispersibility of the mixed powder containing it in matrix materials such as resin, glass, and metal. ５０ It is preferable that the volume cumulative particle size D of the oxide powder is between 0.05 μm and 100 μm. ５０ More preferably, the volume cumulative particle size D of the oxide powder may be 0.05 μm to 50 μm, 0.05 μm to 40 μm, 0.05 μm to 30 μm, 0.05 μm to 20 μm, or 0.05 μm to 10 μm. ５０ The particle size may be 0.1 μm to 50 μm, 0.5 μm to 40 μm, 1 μm to 30 μm, 1.5 μm to 20 μm, or 2 μm to 10 μm.

[0040] The BET specific surface area of ​​the oxide powder is 0.1 m². ２ / g or more 10m ２ It is preferable that the BET specific surface area is less than or equal to 0.1 m². Having a BET specific surface area within this range can improve the dispersibility of the oxide powder in matrix materials such as resins, glass, and metals. The BET specific surface area of ​​the oxide powder is more preferably 0.1 m². ２ / g or more 9m ２ It may be less than or equal to / g, and more preferably 0.3m ２ / g or more 8m ２ / g or less, 0.5m ２ / g or more 7m ２ / g or less, 0.7m ２ / g or more 6m ２ / g or less, 0.9m２ 5 m / g or more ２ / g or less, or 1 m ２ / g or more and 4 m ２ / g or less, respectively, may be.

[0041] The volume resistivity of the oxide powder is preferably 1.0 × 10 ９ Ω·cm or more at 25 °C in order to be suitably used for applications requiring insulation. More preferably, the volume resistivity of the oxide powder is 5.0 × 10 ９ Ω·cm or more, 1.0 × 10 １０ Ω·cm or more, 5.0 × 10 １０ Ω·cm or more, 1.0 × 10 １１ Ω·cm or more, 5.0 × 10 １１ Ω·cm or more, or 1.0 × 10 １２ Ω·cm or more, respectively, may be. In the present specification, the volume resistivity of the oxide powder can be measured, for example, by compressing the oxide powder at a pressure of 63 MPa using a powder resistivity measurement system “MCP-PD51” manufactured by Nitto Seiko Analytic Co., Ltd. and measuring according to the four-terminal method. For samples exceeding the measurement upper limit of this apparatus, pellets compressed at a pressure of 63 MPa separately can be prepared and measured using a high-resistance meter Hiresta UX / MCP-HT800 manufactured by Nitto Seiko Analytic Co., Ltd.

[0042] In the oxide powder, the content of each of uranium (U) and thorium (Th) may be 1 mass ppm or less, and the content of each of lead (Pb) and bismuth (Bi) may be 30 mass ppm or less. Although these elements can emit radiation, the current noise caused by alpha rays may cause malfunction (soft error) of electronic components. By the fact that these elements contained in the oxide powder are within the above ranges, malfunction of the finally manufactured electronic components can be suppressed. The content of uranium (U) and thorium (Th) is more preferably 0.03 mass ppm or less, and even more preferably 0.005 mass ppm or less, respectively. The content of lead (Pb) and bismuth (Bi) is more preferably 10 mass ppm or less, even more preferably 5 mass ppm or less, and still more preferably 1 mass ppm or less, respectively.

[0043] <Resin Composition> In one embodiment of the present invention, a resin composition comprising an oxide powder and a resin component according to any of the above embodiments may be provided. The type and amount of resin component used in the resin composition are not particularly limited and may be appropriately selected and adjusted to obtain the target negative thermal expansion properties or other desired properties. The term "resin composition" as used herein is intended to encompass both a composition that partially contains a solvent such as water or an organic solvent used when mixing the components to prepare the resin composition, and a composition in which such a solvent has been removed under reduced pressure after the preparation of the resin composition.

[0044] Examples of resin components, though not particularly limited, include epoxy resins; polyolefin resins such as polyethylene resins and polypropylene resins; polyvinyl resins such as polyvinyl chloride resins and polyvinyl butyral resins; phenolic resins such as polyphenylene sulfide resins and polystyrene resins such as ABS; polyacrylate resins; polyamide resins; polyimide resins; polyamide-imide resins; polyetherimide resins; silicone resins; polycarbonate resins; ester resins or unsaturated polyester resins such as polybutylene terephthalate (PBT resin) and polyethylene terephthalate (PET resin); fluororesins; liquid crystal polymers; polysulfones; polyethersulfones; aromatic polyether ketone resins such as polyetherether ketones; and mixtures of two or more of these. Among these resins, epoxy resins are preferred from the viewpoint of balancing various properties such as rapid curing, mechanical properties, and heat resistance.

[0045] The amount of resin components constituting the resin composition is not particularly limited, but is usually 5% by mass or more and 95% by mass or less, preferably 10% by mass or more and 80% by mass or less, more preferably 15% by mass or more and 75% by mass or less, and even more preferably 20% by mass or more and 70% by mass or less, relative to the total amount of the resin composition.

[0046] The resin composition may contain, in addition to oxide powder and resin components, at least one inorganic material powder such as silica (silicon dioxide), silicates, titanium oxide, graphite, sapphire (aluminum oxide), magnesium oxide, calcium oxide, silicon nitride, boron nitride, aluminum nitride, various glass materials, concrete materials, and various ceramic materials. The inorganic material powder may be in crushed form, spherical form, or aggregate form such as fumed silica. The inorganic material powder is preferably spherical in order to reduce the viscosity of the resin composition. For example, if the inorganic material powder is silica, it may be crystalline or amorphous. The total amount of oxide powder and inorganic material such as silica (if present) in the resin composition is not particularly limited, but is usually 5% to 95% by mass, preferably 10% to 80% by mass, more preferably 15% to 75% by mass, and even more preferably 20% to 70% by mass, relative to the total amount of the resin composition.

[0047] The resin composition may further contain a curing agent in addition to oxide powder and resin components. Any known curing agent may be used, but examples include acid anhydride compounds, phenolic compounds, amine / amide compounds, and active ester compounds. The amount of curing agent included in the resin composition is not particularly limited, but is usually 0.05% to 10% by mass, preferably 0.1% to 5% by mass, and more preferably 0.5% to 3% by mass, relative to the total amount of the resin composition.

[0048] Examples of acid anhydride compounds that may be included in the resin composition as curing agents include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, polypropylene glycol maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride. Examples of phenolic compounds that may be included in the resin composition as curing agents include dicyclopentadienephenol addition resins, phenol aralkyl resins, naphthol aralkyl resins, triphenylol methane resins, tetraphenylolethane resins, naphthol novolac resins, naphthol-phenol co-condensed novolac resins, naphthol-cresol co-condensed novolac resins, biphenyl-modified phenolic resins, aminotriazine-modified phenolic resins, and modified products thereof.

[0049] Examples of amine / amide compounds that may be included in the resin composition as curing agents include aliphatic polyamines such as ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, polypropylene glycol diamine, diethylenetriamine, triethylenetetramine, and pentaethylenehexamine; aromatic polyamines such as metaxylylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, and phenylenediamine; alicyclic polyamines such as 1,3-bis(aminomethyl)cyclohexane, isophoronediamine, and norbornanediamine; and polyamide resins synthesized from dicyandiamide, a dimer of linolenic acid, and ethylenediamine. Examples of active ester compounds that may be included in the resin composition include compounds having two or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. Preferred examples of active ester compounds include those obtained by the condensation reaction of a carboxylic acid compound and / or a thiocarboxylic acid compound (or its halide) with a hydroxy compound and / or a thiol compound. More preferred examples of active ester compounds include those obtained from a carboxylic acid compound or its halide with a phenol compound and / or a naphthol compound. Examples of carboxylic acid compounds that constitute such active ester compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, etc., or their halides.Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, dihydroxydiphenyl ether, phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, polyhydroxynaphthylene ether, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, and dicyclopentadiene-phenol addition resins.

[0050] The resin composition may further contain other additives. Examples of other additives that may be included in the resin composition include inorganic fillers and fibers other than compounds that are negative thermal expansion materials containing at least one element selected from the group consisting of Cu, Zn, V, Mg, P, and S; lubricants and release agents such as fatty acid amides, fatty acid esters, and metal salts of fatty acids; ultraviolet absorbers such as benzotriazole compounds, benzophenone compounds, and phenyl salicylate compounds; hindered amine stabilizers; phenolic and phosphorus-based antioxidants; tin-based heat stabilizers; various antistatic agents; lubricity improvers such as polysiloxanes; various coloring pigments; silane coupling agents; titanium coupling agents; colorants such as dyes; plasticizers such as waxes and silicone resins; metal oxides other than compounds that are negative thermal expansion materials containing at least one element selected from the group consisting of Cu, Zn, V, Mg, P, and S; composite oxides of multiple metals other than compounds that are negative thermal expansion materials containing at least one element selected from the group consisting of Cu, Zn, V, Mg, P, and S; and mixtures of two or more of these. The amount of such other additives in the resin composition is not particularly limited, but from the viewpoint of maintaining the negative thermal expansion properties and other properties of the resin composition, it may be 5% by mass or less, preferably 3% by mass or less, relative to the total amount of the resin composition.

[0051] The alpha dose of the resin composition was 0.0200 cph / cm². ２The following is preferable: By having the alpha radiation dose of the resin composition within this range, malfunctions caused by current noise generated by alpha radiation can be suppressed when the resin composition is used as a encapsulating material for semiconductor devices. The alpha radiation dose of the resin composition is more preferably 0.0150 cph / cm². ２ Further more preferably, 0.0100 cph / cm² ２ The following is acceptable:

[0052] In this specification, for measuring the alpha dose, a semiconductor-type trace alpha-ray energy distribution analyzer may be used, or a measurement method using a gas prosthenal counter type analyzer or an ionization type analyzer based on the international standard JEDEC STANDARD may be used. When using a semiconductor-type trace alpha-ray energy distribution analyzer, for example, the Hitachi KS-1000 may be used. When using a semiconductor-type trace alpha-ray energy distribution analyzer, alcohol treatment may be performed as a pretreatment. As a more specific measurement method when measuring the alpha dose of a powder sample of a negative thermal expansion material using a semiconductor-type trace alpha-ray energy distribution analyzer, the following procedure may be adopted: (i) Place the sample to be measured (10 g) and ethyl alcohol (25 ml) into a 50 ml beaker and diffuse the beaker in an ultrasonic cleaner for about 1 minute. (ii) Transfer the entire amount of sample in the beaker to the sample stage so that the surface is uniform, and allow to air dry for about 2 hours. (iii) After natural drying, place the sample stage in a vacuum desiccator, start the vacuum pump, and perform vacuum drying for approximately 3 hours or more. (iv) The vacuum-dried sample stage will be used as the sample for trace alpha radiation measurement. (v) Set the sample stage in the chamber of the measuring device and perform measurement for 200 hours. The effective measurement area is 169 cm². ２ The sample size shall be (13 cm x 13 cm). When measuring the alpha dose of a resin composition, the resin composition can be placed directly on the sample stage. The alpha dose shall be the net count value obtained by subtracting the background from the actual measurement result obtained by the above procedure. The surface alpha dose measured in the range of 2.0 to 10 MeV using the above-mentioned Hitachi KS-1000 device may be used as the alpha dose here.

[0053] In measuring alpha dose according to the international standard JEDEC STANDARD, the measurement can be performed by the following procedure: (i) Use a gas flow type alpha dose measuring device. As the sample to be measured, spread powder on a sample base, for example, with a surface area of ​​900 cm². ２ A sample sheet formed into a sheet shape is used. Depending on the device, the sample sheet may be one that fills the maximum measurement area. The sample sheet is placed as a measurement sample in the alpha dose measuring device (gas prosional counter type measuring device or ionization type measuring device), and PR gas is purged into it. The PR gas used conforms to the international standard JEDEC STANDARD. That is, the PR gas used for measurement is a mixture of 90% argon and 10% methane that has been filled into a gas cylinder for more than three weeks, and is a decayed radon (Rn) gas. (ii) After the PR gas is flowed through the alpha dose measuring device in which the sample sheet is placed for 12 hours and left to stand, the alpha dose measurement is performed for 72 hours. (iii) The average alpha dose is measured in "cph / cm²". ２ The alpha radiation dose is calculated as follows: Anomalies (such as counts due to device vibration) are removed from the count for that hour. The following devices are used for the above measurement method: ・Alpha-ray counter: For example, "LACS-4000M" manufactured by Sumika Analysis Center Co., Ltd. ・"Gas flow type alpha-ray measuring device (MODEL-1950)" manufactured by Alpha Science Co., Ltd. ・"Gas Flow Proportional Counter Model 8600A-LB" manufactured by Ordela Co., Ltd. ・"UltraLo-1800" manufactured by XIA Co., Ltd. The alpha radiation dose using this method is measured over a measurement area of ​​1000 cm². ２ From 4000cm ２ This refers to the alpha dose value calculated from the values ​​counted over 72 to 100 hours.

[0054] <Powder mixture> In one embodiment of the present invention, the oxide powder according to any of the above embodiments may be combined with silica-containing powder or other thermally conductive powder to form a powder mixture.

[0055] The silica-containing powder that can constitute the powder mixture is not particularly limited as long as it is a particulate material containing silica. The silica-containing powder may be silica. As silica, fused silica or crystalline silica may be used. The silica-containing powder may be, for example, a core-shell type silica powder in which a silica layer is formed around core particles of resin particles or metal particles, or a hollow silica powder.

[0056] Other thermally conductive powders besides silica-containing powders are not particularly limited and may be any known ones. Examples of other thermally conductive powders include carbon compounds such as graphite and diamond; metal oxides such as aluminum oxide, magnesium oxide, beryllium oxide, titanium oxide, zirconium oxide, and zinc oxide (other than compounds that are negative thermal expansion materials containing at least one element selected from the group consisting of Cu, Zn, V, Mg, P, and S); metal nitrides such as boron nitride, aluminum nitride, and silicon nitride; metal carbides such as boron carbide, aluminum carbide, and silicon carbide; metal hydroxides such as aluminum hydroxide and magnesium hydroxide; metal carbonates such as magnesium carbonate and calcium carbonate; organic polymer calcined products such as acrylonitrile-based polymer calcined products, furan resin calcined products, cresol resin calcined products, polyvinyl chloride calcined products, sugar calcined products, and charcoal calcined products; composite ferrites of ferrite and Zn ferrite; Fe-Al-Si ternary alloys; metal powders, or mixtures thereof.

[0057] The particle shape of silica-containing powder or other thermally conductive powder is preferably substantially spherical from the viewpoint of fluidity when mixed with a matrix material such as resin. The cumulative volume particle size D at 50% cumulative volume, as measured by laser diffraction scattering particle size distribution analysis of silica-containing powder or other thermally conductive powder. ５０ From the same viewpoint as above, the particle size may be, for example, 0.1 μm or more and 10 μm or less, and preferably 0.5 μm or more and 5 μm or less.

[0058] In a powder mixture, the mass ratio of oxide powder to silica-containing powder or other thermally conductive powder may be, for example, between 1:99 and 100:0, between 20:80 and 100:0, preferably between 30:70 and 95:5, more preferably between 40:60 and 90:10, even more preferably between 50:50 and 80:20, and even more preferably between 60:40 and 80:20.

[0059] <Method for Producing Oxide Powder> The method for producing oxide powder of the present invention is not particularly limited, but preferably a method including the following steps can be employed. Step (a): A step of providing a raw material powder for spheroidization treatment, and step (b): A step of performing spheroidization treatment on the raw material powder obtained in step (a) by flame melting or PVD to obtain oxide powder having a spheroidity of 0.7 or more and 1.0 or less, wherein step (a) includes any of the following (i) to (iii): (i) Providing a mixed powder raw material powder for spheroidization treatment by mixing a raw material compound containing the constituent elements of oxide powder and a binder; (ii) Providing a dried powder raw material powder for spheroidization treatment by mixing a solution containing a raw material compound containing the constituent elements of oxide powder, allowing it to precipitate, and drying the precipitate; or (iii) Providing an oxide powder raw material powder for spheroidization treatment by calcining a mixture of raw material compounds containing the constituent elements of oxide powder at least once.

[0060] Step (a) is a step of providing a raw material powder for spheroidization treatment. Step (a) includes any of the following (i) to (iii) as means of providing a raw material powder for spheroidization treatment: (i) providing a mixed powder of raw material powder for spheroidization treatment by mixing a raw material compound containing the constituent elements of oxide powder and a binder; (ii) providing a dried powder of raw material powder for spheroidization treatment by mixing a solution containing a raw material compound containing the constituent elements of oxide powder, allowing it to precipitate, and drying the precipitate; or (iii) providing an oxide powder of raw material powder for spheroidization treatment by calcining a mixture of raw material compounds containing the constituent elements of oxide powder at least once.

[0061] Step (a) may be to provide a mixed powder, which is a raw material powder for spheroidization treatment, by mixing a raw material compound containing the constituent elements of the oxide powder with a binder. In case (i), the raw material compound containing the constituent elements of the oxide powder may be a compound containing at least one element selected from the group consisting of Cu, Zn, V, Mg, P, and S. In a preferred embodiment, a mixture of several compounds containing different combinations of at least one element selected from the group consisting of Cu, Zn, V, Mg, P, and S may be used as the raw material compound containing the constituent elements of the oxide powder. Here, preferably, the compound containing the at least one element or the mixture of several compounds containing different combinations of the at least one element may contain Zn, Mg, and P. Such raw material compounds are not particularly limited as long as they are compounds containing the desired elements. The raw material compound may also be a single element of at least one element selected from the group consisting of Cu, Zn, V, Mg, P, and S. Examples of starting material compounds containing at least one element selected from the group consisting of Cu, Zn, V, Mg, P, and S include compounds containing the element and an oxygen atom, for example, P ２ O ５ , ZnO, CuO, MgO, V ２ O ５ SO ３Examples include one or more of the following. For example, an example of a P-containing compound used as a raw material is phosphorus pentoxide (P ２ O ５ In addition to ), phosphoric acid (H ３ PO ４ ), diammonium hydrogen phosphate ((NH ４ ) ２ HPO ４ ), ammonium dihydrogen phosphate (NH ４ H ２ PO ４ ), ammonium phosphate, pyrophosphate, polyphosphate, Zn ２ P ２ O ７ Mg ２ P ２ O ７ Examples include one or more of the following.

[0062] The binder mixed with the raw material compound is not particularly limited, but polyvinyl alcohol (PVA) can be used. The amount of binder mixed is not particularly limited as long as it does not affect the negative thermal expansion properties of the final oxide powder, but it can be 0.1% by weight or more and 5.0% by weight or less of the total amount of the mixed powder of the raw material compound and binder.

[0063] The method for mixing the raw material compound and the binder is not particularly limited. Typically, mixing can be performed manually or mechanically at room temperature (e.g., 0°C to 50°C, preferably 10°C to 40°C, or 15°C to 35°C) without excessive heating or cooling. Manual mixing can be performed, for example, using a mortar and pestle. For mechanical mixing, grinders such as ball mills and vibratory mills, screw mixers, and Henschl mixers can be used. The mixing time can be appropriately set depending on the processing scale and the specifications of the mixing equipment to ensure a more uniform mixed powder is formed. The mixing time may be, for example, 30 seconds to 1 hour, 1 minute to 40 minutes, or 2 minutes to 20 minutes.

[0064] Step (a) may involve mixing a solution containing a raw material compound containing the constituent elements of the oxide powder, allowing it to precipitate, and drying the precipitate to provide a dried powder raw material powder for spheroidization. In case (ii), the raw material compound containing the constituent elements of the oxide powder may be a compound containing at least one element selected from the group consisting of Cu, Zn, V, Mg, P, and S. In a preferred embodiment, a mixture of multiple compounds containing different combinations of at least one element selected from the group consisting of Cu, Zn, V, Mg, P, and S may be used as the raw material compound containing the constituent elements of the oxide powder. Here, preferably, the compound containing the at least one element or the mixture of multiple compounds containing different combinations of the at least one element may contain Zn, Mg, and P. Such raw material compounds are not particularly limited as long as they are compounds containing the desired elements. The raw material compound may also be a single element of at least one element selected from the group consisting of Cu, Zn, V, Mg, P, and S. Examples of raw material compounds containing at least one element selected from the group consisting of Cu, Zn, V, Mg, P, and S include one or more of the following: chloride salts or hydrates thereof, oxychloride salts or hydrates thereof, acetate salts or hydrates thereof, oxyacetate salts or hydrates thereof, sulfates or hydrates thereof, nitrates or hydrates thereof, carbonates or hydrates thereof, ammonium carbonate salts or hydrates thereof, sodium carbonate salts or hydrates thereof, potassium carbonate salts or hydrates thereof, polyacids or salts or hydrates thereof, oxides or hydrates thereof, etc. Sulfuric acid may be added to the raw material compound as a sulfur raw material if necessary. For example, an example of a P-containing compound used as a raw material compound is phosphoric acid (H ３ PO ４ ), diammonium hydrogen phosphate ((NH ４ ) ２ HPO ４ ), ammonium dihydrogen phosphate (NH ４ H ２ PO ４Examples of raw materials include ammonium phosphate, pyrophosphate, polyphosphate, and one or more other types. The raw materials can be dissolved in a solvent to prepare a solution containing the raw materials, and these solutions can then be mixed. Examples of solvents for the solution containing the raw materials include water or an organic solvent. The concentration of the raw materials in the solution is not particularly limited as it depends on the solvent and the type of raw materials, but may be, for example, 1% by mass or more and 80% by mass or less.

[0065] Furthermore, when mixing solutions containing the raw material compounds, a dispersant may be added as needed. Examples of dispersants include phosphoric acids, polycarboxylic acids, polycarboxylic acid salts, salts of naphthalene sulfonic acid formalin condensate, polyvinyl alcohol, polyethylene glycose, polyvinylpyrrolidone, and copolymers thereof, and two or more of these dispersants may be added in combination.

[0066] Furthermore, during the mixing of the solution containing the raw material compounds, pressurization or heating may be applied as appropriate. Such conditions are not particularly limited, but for example, the reaction can be carried out continuously in a sealed container under pressure at a temperature of 100°C to 250°C, preferably 110°C to 230°C, for a period of, for example, 30 minutes to 100 hours, preferably 1 hour to 80 hours, 2 hours to 60 hours, or 3 hours to 40 hours.

[0067] In such a process (a), the precipitate formed by mixing the solution containing the raw material compound can be recovered by filtration. The precipitate may be purified by washing as needed, for example, by adding water to separate the solids and liquids or by washing with water. Such washing operations may be repeated multiple times.

[0068] By drying the resulting precipitate, a dried powder, which is a raw material powder for spheroidization treatment, is obtained. The drying conditions are not particularly limited, and for example, drying may be carried out at 60°C to 200°C, preferably 50°C to 150°C, for about 30 minutes to 40 hours, preferably about 1 hour to 30 hours.

[0069] Step (a) may provide a raw material powder for spheroidization treatment, which is an oxide powder, by calcining a mixture of raw material compounds containing the constituent elements of the oxide powder at least once. In the case of (iii), the raw material compound containing the constituent elements of the oxide powder may be a compound containing at least one element selected from the group consisting of Cu, Zn, V, Mg, P, and S. In a preferred embodiment, a mixture of multiple compounds containing different combinations of at least one element selected from the group consisting of Cu, Zn, V, Mg, P, and S may be used as the raw material compound containing the constituent elements of the oxide powder. Here, preferably, the compound containing the at least one element or the mixture of multiple compounds containing different combinations of the at least one element may contain Zn, Mg, and P. Such raw material compounds are not particularly limited as long as they are compounds containing the desired elements. The raw material compound may also be a single element of at least one element selected from the group consisting of Cu, Zn, V, Mg, P, and S. Examples of starting material compounds containing at least one element selected from the group consisting of Cu, Zn, V, Mg, P, and S include compounds containing the element and an oxygen atom, for example, P ２ O ５ , ZnO, CuO, MgO, V ２ O ５ SO ３ Examples include one or more of the following. For example, an example of a P-containing compound used as a raw material is phosphorus pentoxide (P ２ O ５ In addition to ), phosphoric acid (H ３ PO ４ ), diammonium hydrogen phosphate ((NH ４ ) ２ HPO ４ ), ammonium dihydrogen phosphate (NH ４ H ２ PO ４ ), ammonium phosphate, pyrophosphate, polyphosphate, Zn ２ P ２ O ７ Mg ２ P ２ O ７Examples include one or more of the following.

[0070] The method for mixing the raw material compounds is not particularly limited. Typically, mixing can be performed manually or mechanically at room temperature (e.g., 0°C to 50°C, preferably 10°C to 40°C, or 15°C to 35°C) without excessive heating or cooling. Manual mixing can be performed, for example, using a mortar and pestle. For mechanical mixing, grinders such as ball mills and vibratory mills, screw mixers, and Henschl mixers can be used. The mixing time can be appropriately set depending on the processing scale and the specifications of the mixing equipment to ensure a more uniform mixed powder is formed. The mixing time may be, for example, 30 seconds to 1 hour, 1 minute to 40 minutes, or 2 minutes to 20 minutes.

[0071] The firing temperature when firing the mixture of raw material compounds is not particularly limited, but may be, for example, 200°C or higher, 250°C or higher, or 300°C or higher, and may be 1200°C or lower, 1000°C or lower, or 900°C or lower. When firing the mixture of raw material compounds multiple times, the firing temperature range for each firing stage may be, for example, 200°C or higher and 1200°C or lower, 250°C or higher and 1000°C or lower, or 300°C or higher and 900°C or lower. From the viewpoint of reliably obtaining oxide powder having the desired composition, it is preferable to set the firing temperature higher as the firing stage progresses. The number of firings may usually be two or three, but may be four or more as needed.

[0072] The calcined product obtained by calcining a mixture of raw material compounds may be optionally pulverized and mixed. If calcination is performed multiple times, pulverization may be performed after each calcination stage. Such pulverization may be dry or wet. Dry pulverization can be performed using, for example, a jet mill with a collision plate type or a jet mill that causes particles to collide with each other. Wet pulverization can be performed, for example, by adding a small amount of dispersant to the pulverized calcined product as needed, and while stirring, supplying beads such as small-diameter zirconia beads to a media-stirred bead mill. In this way, a raw material powder for spheroidization treatment, which is an oxide powder, can be obtained.

[0073] For oxide powders, sieving may be optionally performed. For example, sieving may be performed to determine the volume cumulative particle size D within the preferred range described above. ５０ A suitable sieve can be selected to obtain a compound powder having the properties of [the specified material]. Washing with water and decantation, which may be performed in conjunction with sieving, are preferably repeated until the desired conductivity (e.g., 20 μS / cm or less) is achieved. Drying, which is optionally performed on the sieved oxide powder, may be carried out, for example, at 50°C to 200°C, preferably 80°C to 150°C, for 30 minutes to 10 hours, preferably 1 hour to 8 hours.

[0074] The raw material powder obtained by any of the methods (i) to (iii) above is in an unspherical state. Unspherical powder usually refers to powder with a sphericity of less than 0.7.

[0075] Step (b) is a step in which the raw material powder obtained in step (a) is subjected to a spheroidization treatment by flame melting or PVD to obtain oxide powder in which the spheroidity of the powder is 0.7 or more and 1.0 or less. By step (b), oxide powder that has been spheroidized until the spheroidity of the raw material powder reaches 0.7 or more can be obtained.

[0076] In step (b), if the raw material powder subjected to spheroidization is the mixed powder described in (i) or the dried powder described in (ii), the raw material powder can be oxidized along with the spheroidization process to obtain oxide powder. Furthermore, in step (b), if the raw material powder subjected to sphere purification is the oxide powder described in (iii), spheroidization can be performed by melting the particle surface of the oxide powder without substantially or entirely changing the composition of the powder.

[0077] The flame melting or PVD in step (b) may be carried out at a temperature above the melting point of the raw material powder. By performing flame melting or PVD at a temperature above the melting point of the raw material powder, the particle surface of the raw material powder is melted, reducing surface irregularities and thus improving the sphericity of the powder.

[0078] A more specific example of the conditions for flame melting is, when the raw material powder is the mixed powder described in (i) above, for example, the following: The mixed powder described in (i) above is dispersed in pure water and granulated using a spray-drying device to obtain a powder in which the raw material has aggregated into a spherical shape. This powder is supplied into a flame generated by the combustion of fuel, and only the surface of the mixed powder is heat-treated, thereby providing the thermal energy necessary to obtain the desired crystal structure and promoting sintering, and an oxide powder in which the particle shape has become spherical due to the surface tension caused by melting in the flame can be produced. Note that 13A city gas or the like can be used as the fuel. The combustion rate is preferably in the range of 50,000 kcal / h to 150,000 kcal / h, more preferably in the range of 80,000 kcal / h to 120,000 kcal / h, and the air ratio is preferably 1.0 or higher, more preferably 1.1 or higher, from the viewpoint of suppressing oxygen deficiency.

[0079] When the raw material powder is the dry powder described in (ii) above, for example, the following can be cited. The dry powder described in (ii) above is an aggregate of fine primary particles, and when supplied into a flame generated by the combustion of a fuel, the primary particles undergo sintering due to the heat of the flame, thereby producing a dense spheroidized oxide powder. 13A city gas or the like can be used as the fuel. The combustion rate is preferably in the range of 50,000 kcal / h to 150,000 kcal / h, more preferably in the range of 80,000 kcal / h to 120,000 kcal / h, and the air ratio is preferably 1.0 or higher, more preferably 1.1 or higher, from the viewpoint of suppressing oxygen deficiency.

[0080] When the raw material powder is the oxide powder of (iii) above, for example, the following can be given: The oxide powder of (iii) above is supplied into a flame generated by the combustion of city gas, and only the surface of the oxide powder is melted, thereby producing oxide powder in which the particle shape is spherical due to the surface tension at the time of melting.

[0081] One specific example of the flame melting method is as follows. The following is merely one example, and the specific means of the flame melting method are not limited to this. (1) A dispersion of the raw material powder is prepared by mixing the raw material powder and a solvent such as alcohol in a mass ratio of, for example, about 4:6. (2) A thermal plasma flame is generated using argon gas and oxygen gas as plasma gases. At this time, a mixed gas of air gas and nitrogen gas is supplied to the tail of the thermal plasma flame, i.e., to the terminal end of the thermal plasma flame. (3) Next, the droplet-formed dispersion is supplied into the thermal plasma flame. The dispersion evaporates due to the thermal plasma flame and becomes a gaseous state, and the raw material powder and solvent become gaseous. The alcohol and raw material powder in the dispersion are melted by the oxygen plasma of the thermal plasma flame, resulting in C and H ２ O, CO, CO ２The raw materials are decomposed into carbon. Then, the gaseous raw material powder reacts with C and CO, and a portion of the raw material powder is reduced. (4) Subsequently, the reduced raw material powder is oxidized by the oxygen contained in the mixed gas supplied toward the thermal plasma flame, and the raw material powder is cooled by the mixed gas, thereby generating oxide powder. An example of an apparatus for performing such a flame melting method is the apparatus described in International Publication WO2015 / 065773A1.

[0082] A more specific example of the conditions for PVD is, when the raw material powder is the mixed powder described in (i) above, for example, the following: By supplying the mixed powder described in (i) into a plasma and heat-treating the mixed powder bound by the binder, the thermal energy necessary to obtain the desired crystal structure can be provided, promoting sintering, and oxide powder in which the particle shape has become spherical due to the surface tension caused by melting in the plasma can be produced.

[0083] When the raw material powder is the dried powder described in (ii) above, for example, the following can be given. The dried powder described in (ii) above is an aggregate of fine primary particles, and when supplied into the generated plasma, the primary particles undergo sintering due to the heat of the plasma, thereby producing a dense spheroidized oxide powder.

[0084] When the raw material powder is the oxide powder of (iii) above, for example, the following can be given: The oxide powder of (iii) above is supplied into a plasma and supplied into the plasma generated, and only the surface of the oxide powder is melted, thereby producing an oxide powder in which the particle shape is spherical due to the surface tension during melting.

[0085] Specific examples of the PVD method include the following. The following is merely an example, and the specific means of the PVD method are not limited to this. (1) Plasma is generated to evaporate the raw material powder and produce an evaporated gas. (2) The evaporated gas is passed through a cooling section having a plurality of cooling plates with through holes for the evaporated gas to pass through, thereby generating oxide powder as nanoparticles in the cooled evaporated gas. An example of an apparatus for performing such a PVD method is the apparatus described in Japanese Patent Publication No. JP2014-136200.

[0086] The method for producing oxide powder of the present invention may further include a step of annealing in an appropriate temperature range, usually between 100°C and 900°C, after step (b). Such annealing can smooth the particle surface of the oxide powder and improve the fluidity of the resin composition containing the oxide powder.

[0087] <Method for Manufacturing Electronic Components> For example, an electronic component can be manufactured by (1) applying a resin composition containing oxide powder and resin components according to any of the above embodiments to a first member, (2) applying a second member to the resin composition simultaneously with or after the application of the resin composition to the first member to obtain a component assembly in which the resin composition is sealed between the first and second members, and (3) sealing the space between the first and second members with the resin composition by pressing the component assembly under heat simultaneously with or after obtaining the component assembly. In the manufacture of such an electronic component, a sealing material containing an oxide powder and resin composition can be applied for sealing the electronic component. Furthermore, in the manufacture of such an electronic component, a sealing material containing an oxide powder and resin composition can be applied as an underfill for sealing electronic components. That is, in this application, a sealing material for electronic components containing an oxide powder and resin composition (or formed from said resin composition) is provided; and an underfill for sealing electronic components containing an oxide powder and resin composition (or formed from said resin composition) is also provided. Underfill for electronic component encapsulation can be rephrased as underfill encapsulating material for electronic components.

[0088] The resin composition applied to the first member can be appropriately selected from either an oxide powder or a resin composition containing resin components. The first and second members are not particularly limited, as long as the resin composition can be applied to their surfaces and they can withstand pressure bonding under heat. The materials constituting the first and second members may be the same or different. Specific examples of the first and second members include silicon wafers, metal plates, glass plates, heat-resistant resin plates, and electronic components such as semiconductor chips. For example, one of the first and second members may be a silicon wafer on which electrodes are mounted as a circuit board, and the other may be a semiconductor chip on which electrodes are mounted.

[0089] In a preferred embodiment, an underfill encapsulant is applied to a circuit board, which is a silicon wafer, as an underfill encapsulant. A semiconductor chip, which is a second component, is placed on top of the resin encapsulant. Then, by pressing under heat, the resin encapsulant is cured and the electrodes formed on the semiconductor chip and the electrodes formed on the circuit board are connected simultaneously, thereby sealing the connection between the semiconductor chip and the circuit board with the resin encapsulant, and thus an electronic component (semiconductor device) can be manufactured. The heating temperature for pressing under heat is not particularly limited as long as the molten state of the resin constituting the resin encapsulant is maintained. The pressure applied for pressing under heat is not particularly limited as long as the connection between the semiconductor chip and the circuit board can be reliably achieved. Such a thermocompression bonding method is called the NCP (Non-Conductive Paste) method. Advantages of the NCP method include the ability to shorten the process and curing time, and consequently, the possibility of providing a pre-supplied flip-chip bonding process that can be manufactured at low cost and with low energy. Furthermore, this heat-sealing method suppresses the generation of unfilled areas (voids) in the encapsulant and allows for a sufficient filling rate, even when the sphericity (perfect sphereness) of the mixed powder contained in the resin composition is not high.

[0090] In another preferred embodiment, a film-like semiconductor encapsulant, pre-formed from a resin composition containing oxide powder and resin components, is laminated onto a semiconductor chip, which is a first component. The film-like semiconductor encapsulant is then pressed against a circuit board, which is a second component, under heating to connect electrodes formed on the semiconductor chip and electrodes formed on the circuit board. Subsequently, the resin composition is heat-cured to manufacture an electronic component (semiconductor device) in which the semiconductor chip is mounted on the circuit board. Similar to the embodiments described above, the heating temperature for pressing under heating is not particularly limited as long as the molten state of the resin constituting the resin composition is maintained. The pressure applied for pressing under heating is not particularly limited as long as a reliable connection between the semiconductor chip and the circuit board can be achieved. Such a thermocompression bonding method is called the NCF (Non-Conductive Film) method. Advantageous of the NCF method is that even when the gap between the semiconductor chip and the substrate is narrow, good bonding can be achieved through reliable sealing with suppressed void formation. Furthermore, this thermocompression bonding method, like the NCP method, can suppress the generation of unfilled areas (voids) in the encapsulant and achieve a sufficient filling rate, even when the sphericity (perfect sphereness) of the mixed powder contained in the resin composition is not high.

[0091] In other preferred embodiments, instead of the NCP or NCF methods described above, electronic components (semiconductor devices) can be manufactured by the ACP (Anitropic Conductive Paste) method or ACF (Anitropic Conductive Film) method, which involves mixing predetermined conductive particles with a resin composition containing oxide powder and resin components to form an anisotropic conductive adhesive and performing a similar process. The conductive particles are not particularly limited, but examples include metal particles (e.g., nickel or nickel-gold coated composites), resin particles such as acrylic resin that are metal-plated (e.g., gold-plated), or particles having an insulating film that breaks or melts upon contact with heat or pressure. The average size of the conductive particles may be, for example, 1 μm to 50 μm. This thermocompression bonding method, like the NCP or NCF methods, can suppress the generation of unfilled areas (voids) in the encapsulant and achieve a sufficient filling rate, even when the sphericity (perfect sphereness) of the mixed powder contained in the resin composition is not high.

[0092] The present invention will be described in more detail below with reference to examples. These examples should be understood as merely illustrative and not as limiting the present invention in any way.

[0093] The raw material powder is prepared by a dry synthesis method, as follows: Zn １．６ Mg ０．４ P ２ O ７ A ceramic sintered body was fabricated in the form of a compound powder of a negative thermal expansion material represented by . Specifically, MgO, ZnO, and ammonium dihydrogen phosphate (NH₄) were weighed in stoichiometric ratios of Zn, Mg, and P. ４ H ２ PO ４The mixture was stirred in a bag for 60 seconds until no agglomeration occurred, and the resulting powder was first calcined in an electric furnace at 250°C in air for 5 hours. Next, the resulting calcined material was crushed in a mortar and remixed, and then secondarily calcined in an electric furnace at 350°C in air for 5 hours. Next, the resulting calcined material was crushed in a Force Mill pulverizer for about 30 seconds and remixed, and then calcined in an electric furnace at 900°C in air for 10 hours. After crushing this calcined material in a Force Mill pulverizer for about 30 seconds, it was placed in a plastic container with 1.0 mm diameter zirconia beads and pure water, the plastic container was set in a rocking shaker manufactured by Seiwa Giken Co., Ltd., and wet grinding was performed using the rocking shaker for 1 hour. Subsequently, the zirconia beads were separated using a mesh, and then solid-liquid separation was performed using a small centrifuge (Eppendorf Hi-Mac Technologies Co., Ltd.: CT6E). The solid components were dried at 110°C using a dryer to obtain raw material powder 1. The X-ray diffraction patterns of the compound powder were evaluated using powder X-ray diffraction (XRD) (measurement temperature 295K, characteristic X-rays of CuKα: wavelength λ = 0.15418 nm) and synchrotron radiation temperature-dependent X-ray diffraction (wavelength λ = 0.06521 nm), and Zn １．６ Mg ０．４ P ２ O ７ We confirmed that the crystal structure was formed.

[0094] Example 1 Spheroidization treatment was performed on raw material powder 1 by PVD using a high-frequency induction thermal plasma nanoparticle synthesis apparatus (JEOL Ltd., TP-40020NPS). Argon gas and oxygen gas were used as plasma gases, with an argon gas supply rate of 30 L / min and an oxygen gas supply rate of 3 L / min. The average supply rate of raw material powder 1 was 15 g / min. The chamber pressure was 90 kPa and the treatment time was 4 minutes. Oxide powder 1 was obtained by the spheroidization treatment. An SEM image of oxide powder 1 is shown in Figure 1 (magnification: 1000x).

[0095] Example 2 The oxide powder 1 obtained in Example 1 was subjected to annealing treatment under the conditions of a firing temperature of 500°C and a firing time of 5 hours to obtain annealed oxide powder 2.

[0096] Example 3: Using a flame treatment facility (Chugai Ro Kogyo Co., Ltd., INFLAZ®), raw material powder 1 was subjected to spheroidization treatment by flame melting. 13A city gas was used as fuel. The combustion rate was 100,880 kcal / h, and the air ratio was 1.1. After 60 minutes of treatment, oxide powder 3 was recovered using a multi-cyclone. An SEM image of oxide powder 3 is shown in Figure 2 (magnification: 1000x).

[0097] Example 4 Using a flame treatment facility (Chugai Ro Kogyo Co., Ltd., INFLAZ®), raw material powder 1 was subjected to spheroidization treatment by flame melting. 13A city gas was used as fuel. The combustion rate was 69840 kcal / h, and the air ratio was 1.1. After 60 minutes of treatment, oxide powder 4 was recovered using a multi-cyclone.

[0098] Example 5 Using a flame treatment facility (Chugai Ro Kogyo Co., Ltd., INFLAZ®), raw material powder 1 was subjected to spheroidization treatment by flame melting. 13A city gas was used as fuel. The combustion rate was 69840 kcal / h, and the air ratio was 1.3. After 60 minutes of treatment, oxide powder 5 was recovered using a multi-cyclone.

[0099] Example 6: Starting materials ZnO, MgO, and ammonium dihydrogen phosphate (NH ４ H ２ PO ４ The raw material powder was prepared in the same manner as in "Preparation of Raw Material Powder" above, except that the amount of ) used was changed to obtain the desired composition, and then the spheroidizing treatment was performed in the same manner as in Example 3 to obtain Zn １．８ Mg ０．２ P ２ O ７ The oxide powder 6 represented by was recovered.

[0100] Example 7 Raw materials ZnO, MgO, and ammonium dihydrogen phosphate (NH ４ H ２ PO ４ The raw material powder was prepared in the same manner as in "Preparation of Raw Material Powder" above, except that the amount of ) used was changed to obtain the desired composition, and then the spheroidizing treatment was performed in the same manner as in Example 3 to obtain Zn １．９ Mg ０．１ P ２ O ７The oxide powder 7 represented by was recovered.

[0101] Comparative Example 1 The raw material powder 1 obtained above was used as Comparative Example 1. Figure 2 shows an SEM image of the powder of Comparative Example 1 (magnification: 1000x).

[0102] Comparative Example 2: A powder (raw material powder 2) obtained in the same manner as in Comparative Example 1 was used as Comparative Example 2, except that the wet grinding time using a rocking shaker was 20 minutes.

[0103] Comparative Example 3: A powder (raw material powder 3) obtained in the same manner as in Comparative Example 1, except that the wet grinding time using a rocking shaker was 1 minute, was used as Comparative Example 3.

[0104] Sphericity Measurement Method The obtained powder sample was observed at a magnification of 1000x using a scanning electron microscope (JEOL Ltd. "JSM-IT800"), and three SEM images were obtained. For each of the three obtained SEM images, image adjustment was performed by binarization of the particles and background. Subsequently, image analysis was performed on each of the 100 particles in the image. Using the image processing software ImageJ, drawing was performed along the particles, and after all drawing was completed, particle analysis was performed to obtain the average area and average circumference of each particle. Then, the sphericity for one SEM image was calculated using equation (1). The arithmetic mean of the sphericity obtained from the three images was taken as the sphericity (true sphericity) of the powder. Sphericity of powder = 4π × (average area of ​​one particle) / (average circumference of one particle) ２ ... (1)

[0105] Method for measuring average particle size: The obtained powder sample is placed in pure water and dispersed by ultrasonic irradiation (40W, 3 minutes). Then, using a particle size distribution analyzer (Microtrac (product name) MT-3300EXII (model number) manufactured by Microtrac-Bell Co., Ltd.), the cumulative volume particle size D at 10% cumulative volume is measured using the laser diffraction scattering particle size distribution method. １０ Volume cumulative particle size D at a cumulative volume of 50% ５０ , and volume cumulative particle size D at 90% of cumulative volume ９０ We measured it.

[0106] BET Specific Surface Area Measurement Method Using a specific surface area measuring device ("Macorb (HM model-1201)" manufactured by Mountec Co., Ltd.), the BET specific surface area of ​​the powder samples obtained in each example and comparative example was measured in accordance with JIS Z 8830:2013 (Method for measuring the specific surface area of ​​powders (solids) by gas adsorption). A mixed gas of helium as the carrier gas and nitrogen as the adsorbate gas was used. The degassing conditions were 300°C for 10 minutes.

[0107] Method for Measuring Paste Viscosity 0.73 g of powder sample and 4.37 g of epoxy resin main component (jER806H) were mixed using a two-bead 3.0 mm diameter zirconia bead kneader (Awatori Rentaro ARE-310, manufactured by THINKY) (rotation speed: 2000 rpm, time: 30 seconds), and degassed (rotation speed: 2200 rpm, time: 30 seconds or more). A 3.0 mm diameter zirconia bead was removed from the mixture, and the resulting resin mixture was measured using a cone-plate viscometer (manufactured by Brook Field) under the following conditions: • Circular plate: 40 mm diameter • Sample thickness: 1 mm • Temperature: 25 ± 1 °C • Rotation speed: 0.03 rpm

[0108] Method for Measuring Paste Viscosity by Shear Rate 0.73 g of the powder sample obtained in the examples and comparative examples and 4.37 g of epoxy resin main component (jER806H) were mixed (rotation speed: 2000 rpm, time: 30 seconds) and degassed (rotation speed: 2200 rpm, time: 30 seconds or more) using a two-bead kneader with φ3.0 mm zirconia beads (Awatori Rentaro ARE-310, manufactured by THINKY) and degassed (rotation speed: 2200 rpm, time: 30 seconds or more). A 3.0 mm diameter zirconia bead was removed from the mixture, and the viscosity of the resulting resin mixture at 25°C was measured using a rotary rheometer (Anton Paar "MCR-92") under the following conditions: ・Circular plate: diameter 25 mm ・Sample thickness: 1 mm ・Temperature: 25 ± 1°C ・Shear rate: 0.1 → 1000 / s (logarithmic slope) Figure 4 shows the paste viscosity of each sample at different shear rates.

[0109] XRD Peak Observation and Intensity Ratio Measurement Method For the powder samples obtained in each example and comparative example, peaks were observed by scanning with a powder X-ray diffractometer (Rigaku "MiniFlex2") at room temperature using Cu-Kα rays under the conditions of tube voltage 30kV, tube current 15mA, scanning speed 5° / min, and scanning angle 2θ = 5° to 80°. Other than the above, the operating conditions for powder X-ray diffraction were as follows: ・Slit: DS-SS; 1.25 degrees, RS; 0.3 mm ・Monochromator graphite step: 0.02° ・Counting method: Constant counting method ・X-ray analysis software: PDXL2 Version 2.9.1.0 Using a powder X-ray diffractometer under the above conditions, the XRD intensity ratios 1 (-6 0 2) / (0 2 2) and 2 (2 0 -1) / (0 2 2) were measured at 30°C, 50°C, and 100°C, respectively. Here, the peak intensity of "(-6 0 2)" refers to the peak intensity of the (-6 0 2) plane that appears at diffraction angles 2θ = 29.3 to 29.55°, the peak intensity of "(0 2 2)" refers to the peak intensity of the (0 2 2) plane that appears at diffraction angles 2θ = 29.6 to 29.7°, and the peak intensity of "(2 0 - 1)" refers to the peak intensity of the (2 0 - 1) plane that appears at 30.0 to 30.2°.

[0110] Method for Measuring the Dimensional Change Ratio (ΔL / L) of Epoxy Resin Compositions by TMA 3.90 g of powder samples obtained in the examples and comparative examples, along with 1.28 g of the epoxy resin main component, 0.23 g of diluent, and 0.55 g of curing agent, were mixed (rotation speed: 2000 rpm, time: 30 seconds) and degassed (rotation speed: 2200 rpm, time: 30 seconds or more) using a kneader (Awatori Rentaro ARE-310, manufactured by THINKY). The resulting resin composition was placed in a cylindrical container with a diameter of 10 mm and degassed in a vacuum container. The degassed resin composition was heated in a dryer at 80°C for 1 hour and then at 150°C for 3 hours to cure. The cured resin composition was cut into pieces measuring 10 mm (diameter) x 5 mm (height) and processed into tablets. The dimensional change ratio of the resin composition processed into tablets was measured. • Epoxy resin main component: JER-807, JER-806H, JER-806 (manufactured by Mitsubishi Chemical Corporation) • Diluent: YED216M (manufactured by Mitsubishi Chemical Corporation) • Hardener: JER Cure 113 (manufactured by Mitsubishi Chemical Corporation)

[0111] The measurement conditions for the dimensional change ratio using TMA were as follows: • Apparatus: TA7000 (Hitachi High-Tech Thermomechanical Analyzer TMA7000 series) • Cycle 1: The sample was heated from 30°C to 150°C in an atmospheric environment at a heating rate of 6°C / min while applying a load of 100 mN. It was then allowed to cool naturally to room temperature while the load remained applied. • Cycle 2: The sample was heated from 30°C to 150°C in an atmospheric environment at a heating rate of 1°C / min.

[0112] Preparation of a sintered body made solely from powder and measurement of the dimensional change ratio (ΔL / L) by TMA. 1 g of the powder sample obtained in the examples and comparative examples, along with 0.1 g of a 10% granulated binder (PV-217, manufactured by AS ONE) solution and 0.2 g of ethanol, were mixed in an agate mortar. The mixture was placed into a tablet molding die and then molded into a tablet using a pressure press to obtain a molded body measuring 10 mm (diameter) x 5 mm (height). The molded body was dried at 110°C for 1 hour, and then fired in an electric furnace at 900°C in air for 5 hours to create a sintered body. Subsequently, the dimensional change ratio of the sintered body was measured.

[0113] The measurement conditions for the coefficient of linear expansion using TMA were as follows: • Apparatus: TA7000 (Hitachi High-Tech Thermomechanical Analyzer TMA7000 series) • One cycle only: The sample was heated from 30°C to 250°C in an atmospheric environment at a heating rate of 6°C / min.

[0114] Tables 1-1 and 1-2 show the annealing conditions, average particle size, sphericity, various paste viscosities, XRD strength ratio, and dimensional change ratio for each example and comparative example. Table 1-2 also shows the dimensional change ratio for the epoxy resin alone. From the results shown in Tables 1-1 and 1-2, it can be seen that the oxide powders of each example that underwent sphericization treatment had high sphericity (i.e., were perfectly spherical). Furthermore, it can be seen that the resin composition had high fluidity.

[0115]

[0116]

[0117]

[0118] The novel negative thermal expansion material according to the present invention provides a material with high sphericity that does not cause a decrease in the fluidity or increase in viscosity of the composition even when mixed with a matrix material. Therefore, it is possible to suppress the occurrence of product defects during the manufacture of highly advanced electronic and optical equipment, fuel cells, sensors, etc., as well as damage and deterioration during repeated use. Furthermore, it is possible to reduce waste during manufacturing and use, and to reduce energy costs. In these respects, the novel negative thermal expansion material according to the present invention enables the sustainable management and efficient use of natural resources and promotes decarbonization (carbon neutrality) in the manufacture and use of negative thermal expansion materials and electronic equipment, etc.

Claims

1. An oxide powder comprising at least one element selected from the group consisting of Cu, Zn, V, Mg, P, and S, wherein the sphericity of the oxide powder is 0.7 or more and 1.0 or less, and the dimensional change ratio (ΔL / L) in a temperature range of at least 0°C to 200°C is less than 0, or the coefficient of linear expansion (α) in a temperature range of at least 0°C to 200°C is less than 0 ppm / K.

2. The oxide powder according to claim 1, comprising at least two elements selected from the group consisting of Cu, Zn, V, Mg, P, and S.

3. The oxide powder according to claim 2, comprising Zn, Mg, and P.

4. General formula (1) Zn ２－ｘ Mg ｘ P ２ O ７±δ The oxide powder according to claim 1, comprising at least one powder of an oxide represented by the formula (wherein part or all of Mg may be substituted with Sr and / or Ca and / or Ba, where 0 ≤ x ≤ 2 and δ is a value determined to satisfy the charge neutrality condition).

5. General formula (1) Zn ２－ｘ Mg ｘ P ２ O ７±δ The oxide powder according to claim 4, wherein in the formula, 0.05 ≤ x ≤ 0.

5.

6. The oxide powder according to any one of claims 1 to 5, wherein the sphericity of the oxide powder is 0.8 or more and 1.0 or less.

7. A resin composition comprising the oxide powder and resin component according to any one of claims 1 to 5.

8. The resin composition according to claim 7, further comprising a curing agent.

9. The resin composition according to claim 7, wherein the α-ray dose is 0.0200 cph / cm or less. ２ ​ 10. A powder mixture comprising the oxide powder and silica-containing powder or other thermally conductive powder according to any one of claims 1 to 5.

11. Encapsulating material for electronic components comprising the resin composition described in claim 7.

12. An underfill for encapsulating electronic components comprising the resin composition described in claim 7.

13. A method for producing oxide powder according to any one of claims 1 to 5, comprising: step (a): providing raw material powder for spheroidization treatment; and step (b): performing flame melting or PVD spheroidization treatment on the raw material powder obtained in step (a) to obtain oxide powder having a spheroidity of 0.7 or more and 1.0 or less, wherein step (a) comprises any of the following (i) to (iii): (i) providing a mixed powder of raw material powder for spheroidization treatment by mixing a raw material compound containing the constituent elements of oxide powder and a binder; (ii) providing a dried powder of raw material powder for spheroidization treatment by mixing a solution containing a raw material compound containing the constituent elements of oxide powder, allowing it to precipitate, and drying the precipitate; or (iii) providing an oxide powder of raw material powder for spheroidization treatment by calcining a mixture of raw material compounds containing the constituent elements of oxide powder at least once.

14. The manufacturing method according to claim 13, wherein the flame melting or PVD in step (b) is carried out in a temperature range above the melting point of the raw material powder.

15. The manufacturing method according to claim 13, further comprising a step of performing an annealing treatment at a temperature range of 100°C to 900°C after step (b).

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