WO2023189589A1 - Inorganic powder, method for producing same, and resin composition - Google Patents

Inorganic powder, method for producing same, and resin composition Download PDF

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WO2023189589A1
WO2023189589A1 PCT/JP2023/010036 JP2023010036W WO2023189589A1 WO 2023189589 A1 WO2023189589 A1 WO 2023189589A1 JP 2023010036 W JP2023010036 W JP 2023010036W WO 2023189589 A1 WO2023189589 A1 WO 2023189589A1
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phase
inorganic powder
crystalline silica
powder
cristobalite
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PCT/JP2023/010036
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French (fr)
Japanese (ja)
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拓司 小林
元晴 深澤
拓人 岡部
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デンカ株式会社
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/113—Silicon oxides; Hydrates thereof
    • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
    • C01B33/18—Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/34—Silicon-containing compounds
    • C08K3/36—Silica
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L101/00—Compositions of unspecified macromolecular compounds

Definitions

  • the present invention relates to an inorganic powder, a method for producing the same, and a resin composition.
  • Inorganic powders such as silica and titanium oxide are known as resin fillers, and are used, for example, as fillers for sealing materials for semiconductor devices.
  • silica powder is an inorganic compound naturally produced as silica stone, and is a highly versatile filler.
  • Spherical silica powder When using silica powder as a filler, spherical silica powder is widely used from the viewpoint of improving dispersibility in resin.
  • Spherical silica powder is generally amorphous and has a low coefficient of thermal expansion and low thermal conductivity.
  • the thermal expansion coefficient of the amorphous silica powder is 0.5 ppm/K, and the thermal conductivity is 1.4 W/mK.
  • warping or cracking may occur during reflow or during operation of a semiconductor device. Another problem is that it is difficult to dissipate heat generated from semiconductor devices due to low thermal conductivity.
  • crystalline silica powders with a particularly high proportion of cristobalite crystal phase have a higher coefficient of thermal expansion than crystalline silica powders with other crystal structures. are doing.
  • the thermal expansion coefficient of cristobalite powder is approximately 17 to 36 ppm/K, and various studies have been made as a filler capable of achieving a high thermal expansion coefficient.
  • Patent Document 3 proposes a resin composition for an encapsulant containing crystalline silica powder containing a certain amount of cristobalite crystal phase.
  • Patent Document 4 describes a method for manufacturing at low cost a spherical crystalline silica powder containing a cristobalite crystal phase, which can be applied as a filler for an encapsulant.
  • the crystal structure of cristobalite undergoes a phase transition from ⁇ phase to ⁇ phase in a specific temperature range of 220 to 280°C.
  • the phase transition start temperature overlaps with the heating temperature during reflow, so the thermal expansion behavior accompanying the phase transition during solder melting causes the interface between the encapsulant and the substrate to Cracks and cracks may occur, making it extremely difficult to handle.
  • crystalline silica powder with a high coefficient of thermal expansion is preferred from the viewpoint of being less likely to cause warping or cracking during reflow or during the operation of semiconductor devices;
  • the cristobalite powder that can achieve this has a problem in that it tends to crack or break at the interface between the substrate and the sealant when melting solder because it exhibits specific thermal expansion behavior associated with the phase transition of cristobalite. From these viewpoints, there is a need for a filler that does not cause a sudden increase in the coefficient of thermal expansion even at heating temperatures during reflow and can achieve a high coefficient of thermal expansion.
  • thermomechanical analysis TMA analysis of a typical cristobalite powder shows that the coefficient of thermal expansion rapidly rises in a narrow temperature range during phase transition from ⁇ phase to ⁇ phase. Therefore, cristobalite powder has a very large coefficient of thermal expansion.
  • Thermal expansion coefficient is a value that expresses the rate of volumetric expansion or volumetric contraction of powder per 1°C, and as mentioned above, cristobalite powder, which has a very large coefficient of thermal expansion, is used at the interface between the sealing material and the substrate. It is easy to crack and break, making it difficult to handle.
  • an object of the present invention is to provide an inorganic powder that has a lower coefficient of thermal expansion than conventional cristobalite powder and can achieve a high coefficient of thermal expansion, a method for producing the same, and a resin composition containing the inorganic powder. .
  • the present inventors found that among crystalline silica powders containing 30% by mass or more of an ⁇ -cristobalite phase, two or more types of crystalline silica powders having different ⁇ - ⁇ phase transition initiation temperatures and X-ray diffraction We have found that all of the above-mentioned problems can be solved if the inorganic powder has a peak half-width of the ⁇ -cristobalite phase within a certain range, and we have completed the present invention. That is, the present invention has the following aspects.
  • An inorganic powder wherein the inorganic powder includes at least two types of crystalline silica powders having different ⁇ - ⁇ phase transition initiation temperatures, and each of the at least two types of crystalline silica powders has a crystalline phase. and the ratio of the ⁇ -cristobalite phase to the total amount (100 mass%) of the amorphous phase is 30% by mass or more, and the half-value width ( An inorganic powder having a FWHM) of 0.120° to 0.300°.
  • an inorganic powder that has a lower coefficient of thermal expansion than conventional cristobalite powder and can achieve a high coefficient of thermal expansion, a method for producing the same, and a resin composition containing the inorganic powder.
  • TMA curves of spherical cristobalite powder of Comparative Example 3 is an example of TMA curves of spherical cristobalite powder of Comparative Example 3, spherical amorphous silica powder of Comparative Example 4, and crushed quartz powder of Comparative Example 5.
  • This is an example of a DSC curve for explaining how to determine the ⁇ - ⁇ phase transition starting temperature.
  • 1 is an example of a DSC curve of the inorganic powder of Example 1.
  • 1 is an example of TMA curves of the inorganic powder of Example 1 and the spherical cristobalite powder of Comparative Example 3.
  • ⁇ means “more than or less than”.
  • 220 to 280°C means 220°C or more and 280°C or less.
  • binder means "aggregate of a plurality of particles”.
  • the inorganic powder according to the present embodiment includes at least two types of crystalline silica powders having different ⁇ - ⁇ phase transition start temperatures, and each of the at least two types of crystalline silica powders has a crystalline phase and an amorphous phase.
  • the ratio of the ⁇ -cristobalite phase to the total amount (100 mass%) of the inorganic powder is 30% by mass or more, and the half-width at half maximum (FWHM) of the (101 plane) It is characterized by being between .120° and 0.300°. According to the inorganic powder according to this embodiment, it has a lower coefficient of thermal expansion than conventional cristobalite powder and can achieve a high coefficient of thermal expansion.
  • CTE max is a general spherical cristobalite powder (crystalline silica powder consisting of only one type of spherical cristobalite powder with a crystallinity rate and a proportion of ⁇ -cristobalite phase of 90% by mass or more) ) means lower than the maximum value of the thermal expansion coefficient (50 ⁇ 10 ⁇ 5 /K or more).
  • the full width of half maximum intensity (FWHM) of the (101 plane) X-ray diffraction peak (XRD) of the ⁇ -cristobalite phase (hereinafter simply referred to as "half maximum intensity") ) is 0.120° to 0.300°, preferably 0.140° to 0.300°, and more preferably 0.150° to 0.260°.
  • the half width can be measured under the following conditions.
  • X-ray diffraction of inorganic powder The X-ray diffraction peak of the inorganic powder is measured under the following conditions using an XRD apparatus (for example, manufactured by Rigaku Co., Ltd., product name "RINT-Ultima IV"). Thereafter, the half-value width of the (101 plane) of the ⁇ -cristobalite phase is calculated using XRD analysis software (for example, manufactured by Rigaku Co., Ltd., product name "Integrated Powder X-ray Analysis Software PDXL2").
  • X-ray source CuK ⁇ Tube voltage: 40kV Tube current: 40mA Scan speed: 4.0°/min 2 ⁇ scan range: 10° to 50°
  • the inorganic powder that satisfies the above-mentioned half-width is, for example, a crystalline silica powder having a wide half-width of the (101 plane) in the ⁇ -cristobalite phase (for example, the half-width of the (101 plane) is close to or larger than 0.300°.
  • crystalline silica powder more preferably the crystalline silica powder whose half-width is 0.280° or more and 0.380° or less
  • the inorganic powder according to this embodiment includes at least two types of crystalline silica powders having different ⁇ - ⁇ phase transition initiation temperatures.
  • the ⁇ - ⁇ phase transition initiation temperature of crystalline silica powder can be determined, for example, by heating the crystalline silica powder from room temperature to 300°C at a heating rate of 10°C/min using a differential scanning calorimeter. It can be identified from the starting temperature of the endothermic peak in the DSC curve. More specifically, a line drawn along the slope of the baseline of the starting temperature of the endothermic peak of the DSC curve, and a line drawn along the first inflection point of the endothermic peak extending toward the bottom of the graph.
  • FIG. 2 is an example of a DSC curve of the spherical cristobalite powder (one type) of Comparative Example 3. Further, in this specification, "room temperature” refers to 0 to 40°C.
  • crystalline silica powders with different ⁇ - ⁇ phase transition start temperatures are defined as “crystalline silica powders with different ⁇ - ⁇ phase transition start temperatures” (provided that the ⁇ - ⁇ phase transition start temperatures differ by 1°C or more (however, the difference in ⁇ - ⁇ phase transition end temperatures is means crystalline silica powder (excluding those whose temperature is below 5°C).
  • ⁇ - ⁇ phase transition end temperature refers to the line drawn along the slope of the baseline of the end temperature of the endothermic peak of the DSC curve mentioned above, and the last inflection point of the endothermic peak extending toward the upper side of the graph. (the inflection point on the high temperature side of the peak). For example, in the case of the DSC curve shown in FIG.
  • the intersection point (end point 2) means the temperature. Note that whether or not the inorganic powder according to the present embodiment contains two or more types of crystalline silica powder with different ⁇ - ⁇ phase transition start temperatures can be determined by measuring the inorganic powder with a differential scanning calorimeter under the above-mentioned conditions. This can be confirmed by the observation of multiple endothermic peaks within the resulting DSC curve.
  • FIG. 3 is an example of a DSC curve of the inorganic powder of Example 1. As shown in FIG. 3, the DSC curve of the inorganic powder according to this embodiment may have multiple endothermic peaks.
  • the inorganic powder according to the present embodiment is a mixed powder containing two or more types of crystalline silica powders having different ⁇ - ⁇ phase transition start temperatures.
  • the ⁇ - ⁇ phase transition start temperature of the crystalline silica powder contained in the inorganic powder can be adjusted within a range where the half-width is 0.120° to 0.300°.
  • the inorganic powder is a crystalline silica powder having an ⁇ - ⁇ phase transition starting temperature within a range of 170 to 280°C, and the ⁇ - ⁇ phase transition starting temperature differs by 1°C or more (however, ⁇ - At least two types of crystalline silica powder (excluding those with a difference in ⁇ -phase transition completion temperature of 5° C. or less) may be included.
  • the upper limit of the type of crystalline silica powder contained in the inorganic powder is not particularly limited as long as it has the effects of the present invention.
  • the number of types of crystalline silica powder in the inorganic powder may be three or four types. From the viewpoint of balancing production costs, it is preferable that the inorganic powder contains 12 or less types of crystalline silica powders having different ⁇ - ⁇ phase transition initiation temperatures.
  • FIG. 1 is a graph including the TMA curve of the spherical cristobalite powder of Comparative Example 3 (general spherical cristobalite powder).
  • the TMA curve of the spherical cristobalite powder in FIG. 1 shows a sharp rise at around 240 to 250°C, that is, a rapid increase in the coefficient of thermal expansion.
  • the thermal expansion coefficient at this time is approximately 50 ⁇ 10 ⁇ 5 /K.
  • the ratio of the ⁇ -cristobalite phase to the total amount (100 mass%) of the crystalline phase and the amorphous phase of at least two types of crystalline silica powders contained in the inorganic powder is 30% by mass or more.
  • the content may be 40% by mass or more, or may be 50% by mass or more.
  • the ratio of the ⁇ -cristobalite phase to the total amount (100 mass%) of the crystalline phase and the amorphous phase of the crystalline silica powder contained in the inorganic powder is 30% by mass or more, so that the coefficient of thermal expansion is high. An inorganic powder is obtained.
  • crystalline silica powder refers to silica powder containing 30% by mass or more of a crystalline phase and 30% by mass or more of an ⁇ -cristobalite phase (i.e., crystallization rate of 30% by mass or more, cristobalite refers to silica powder with a conversion rate of 30% by mass or more).
  • the crystalline phase, amorphous phase proportion, and ⁇ -cristobalite phase proportion of the crystalline silica powder can be measured by X-ray diffraction. Specifically, it can be measured by the following method. Note that although the following method shows calculation methods for ⁇ -cristobalite phase, quartz phase, and tridymite phase, other silica crystal phases can also be calculated using the same method.
  • ⁇ Ratio of crystalline phase of crystalline silica powder and composition analysis of crystalline phase First, the composition of the crystal phase of the crystalline silica powder is confirmed by X-ray diffraction measurement (XRD measurement). Specifically, the X-ray diffraction peak of the crystalline silica powder is measured under the following conditions using an XRD apparatus (for example, manufactured by Rigaku Co., Ltd., product name "RINT-Ultima IV").
  • the proportion of each crystal phase may be calculated from the peak intensity ratio obtained by XRD measurement.
  • each peak is separated.
  • the integrated intensity of the peak can be calculated using, for example, integrated powder X-ray analysis software (for example, manufactured by Rigaku Co., Ltd., product name "PDXL2").
  • subscripts (101) and (221) represent plane indices of the diffraction peaks of each crystal phase.
  • Percentage of quartz phase Iq(101)/Sq(101) ⁇ 100...(5)
  • Proportion of ⁇ -cristobalite phase Ic (101) / Sc (101) ⁇ 100 (6)
  • (Ratio of tridymite phase) It(221)/St(221) ⁇ 100...(7)
  • (Ratio of crystal phase) (Ratio of quartz phase) + (Ratio of ⁇ -cristobalite phase) + (Ratio of tridymite phase) ... (8)
  • the crystallinity of the crystalline silica powder may be 30% by mass or more, 50% by mass or more, or 70% by mass or more.
  • the crystalline silica powder can contain a crystalline phase and an amorphous phase (hereinafter sometimes referred to as "other phases") other than the ⁇ -cristobalite phase. That is, the crystalline silica powder may include an ⁇ -cristobalite phase and at least one selected from a quartz phase, a tridymite phase, and an amorphous phase.
  • the crystalline silica powder contains at least one selected from a quartz phase, a tridymite phase, and an amorphous phase, thermal expansion behavior tends to occur in a low temperature range (around 200 ° C.), and the TMA curve becomes more linear. Cheap.
  • the proportion of other phases other than the ⁇ -cristobalite phase is preferably 70% by mass or less, and 50% by mass or less based on the total amount (100% by mass) of all crystalline phases and amorphous phases. More preferred. From the viewpoint of easily obtaining an inorganic powder with a higher coefficient of thermal expansion, it may contain crystalline silica powder having only an ⁇ -cristobalite phase as a crystalline phase.
  • the ⁇ - ⁇ phase transition start temperature of crystalline silica powder (A) (hereinafter referred to as "silica powder (A)"), which is included in the inorganic powder and has the lowest ⁇ - ⁇ phase transition start temperature.
  • (TA) and the ⁇ - ⁇ phase transition initiation temperature (TB) of crystalline silica powder (B) (hereinafter referred to as “silica powder (B)") with the highest ⁇ - ⁇ phase transition initiation temperature (TB-TA) is preferably at most 90°C, more preferably at most 80°C, even more preferably at most 75°C.
  • (TB-TA) may be between 1 and 90°C, may be between 5 and 90°C, or may be between 10 and 90°C.
  • the ⁇ - ⁇ phase transition initiation temperature (TA) of the silica powder (A) is preferably 170 to 250°C, more preferably 180 to 240°C, even more preferably 180 to 235°C.
  • the ⁇ - ⁇ phase transition initiation temperature (TB) of the silica powder (B) is preferably 200 to 280°C, more preferably 230 to 280°C, even more preferably 235 to 275°C, and even more preferably 240 to 280°C. It is particularly preferred that the temperature is between 270°C and 270°C. If (TA) and (TB) are within the above range, (TB-TA) can be easily adjusted to 90° C. or less. Moreover, by including such silica powders (A) and (B), a relatively linear TMA curve can be easily obtained, and an inorganic powder with a lower coefficient of thermal expansion can be easily obtained.
  • the inorganic powder according to the present embodiment contains two or more types of crystalline silica powders having different ⁇ - ⁇ phase transition start temperatures.
  • the TMA curve of spherical cristobalite powder in Figure 1 the TMA curve of crystalline silica powder containing a certain amount or more of ⁇ -cristobalite phase usually shows a change in thermal expansion coefficient due to phase transition from ⁇ phase to ⁇ phase. A sudden rise occurs. As a result, the coefficient of thermal expansion of the spherical cristobalite powder becomes very large.
  • the inorganic powder according to this embodiment provides a relatively linear TMA curve.
  • the present inventor found that the crystalline silica powders containing a certain amount of ⁇ -cristobalite phase, which have different half-widths, each exhibit different thermal properties, and by combining multiple types and adjusting the half-width to an appropriate half-width, It has been found that an inorganic powder with a low coefficient of thermal expansion can be obtained by suppressing a rapid increase in the coefficient of thermal expansion.
  • Patent Document 4 The conventional technology described in Patent Document 4 and the like relates to a cristobalite powder having a high crystallinity, in which the crystallinity is 90% by mass or more and the proportion of the ⁇ -cristobalite phase is 95% by mass or more.
  • Such highly crystallized cristobalite powder is known to have a relatively narrow half-width.
  • no study has been made on controlling the thermal expansion behavior of highly crystallized cristobalite powder.
  • the thermal expansion behavior of cristobalite powder is often complicatedly related to factors such as the type of additive used during production, firing time, firing temperature, and particle size. Deriving correlations is very difficult.
  • the particles constituting the crystalline silica powder contained in the inorganic powder according to this embodiment have a spherical shape.
  • the particle shape is spherical means that when the particles contained in the crystalline silica powder are observed under a microscope, the projected view (including a three-dimensional view and a plan view) has a shape close to a circle. means.
  • the average circularity of the crystalline silica powder is preferably 0.80 or more, more preferably 0.85 or more, and even more preferably 0.90 or more.
  • the average circularity of the crystalline silica powder is 0.80 or more, it becomes easy to adjust the average circularity of the inorganic powder according to this embodiment to a preferable range. Further, the dispersibility of the inorganic powder according to the present embodiment into the resin can be easily improved. In addition, it is easy to prevent the resin from increasing in viscosity and decreasing its fluidity, and its processability and filling properties are less likely to deteriorate.
  • the "average circularity" of crystalline silica powder can be calculated by the following method. ⁇ Average circularity> After fixing the crystalline silica powder with carbon tape, osmium coating is performed.
  • the particles are photographed using a scanning electron microscope (for example, JEOL Ltd., product name: JSM-7001F SHL) at a magnification of 200 to 50,000 times, and an image analysis device (for example, Nippon Roper (Japan Roper)) is used to photograph the particles.
  • a scanning electron microscope for example, JEOL Ltd., product name: JSM-7001F SHL
  • an image analysis device for example, Nippon Roper (Japan Roper)
  • S projected area
  • L projected perimeter
  • Calculate Calculate.
  • the average particle diameter (D50) of the crystalline silica powder according to the present embodiment is preferably 1 to 100 ⁇ m, more preferably 4 to 100 ⁇ m, and even more preferably 5 to 80 ⁇ m. If the average particle diameter (D50) of the crystalline silica powder is within the above range, the filling properties of the obtained inorganic powder into the resin tend to be better.
  • the average particle diameter of crystalline silica powder is the particle diameter (D50) at which the cumulative value corresponds to 50% in the volume-based cumulative particle size distribution measured using a laser diffraction particle size distribution analyzer. Point.
  • the cumulative particle size distribution is represented by a distribution curve with the horizontal axis representing the particle diameter ( ⁇ m) and the vertical axis representing the cumulative value (%).
  • the specific surface area of the crystalline silica powder contained in the inorganic powder according to this embodiment is preferably 0.1 to 10 m 2 /g, more preferably 0.3 to 5 m 2 /g.
  • the specific surface area of the crystalline silica powder can be measured by the BET method.
  • ⁇ Method for measuring specific surface area> Fill a measuring cell with 1 g of crystalline silica powder, and use a fully automatic specific surface area diameter measuring device (for example, manufactured by Mountech, product name: Macsorb HM model-1201 (BET-point method)) to measure the amount of crystalline silica powder. Measure the specific surface area.
  • the degassing conditions before measurement can be 200° C. and 10 minutes.
  • the average particle density of the crystalline silica powder contained in the inorganic powder according to the present embodiment is preferably 2.20 to 2.50 g/cm 3 , more preferably 2.28 to 2.40 g/cm 3 . If the average particle density of the crystalline silica powder is within the above range, the thermal conductivity tends to be higher than that of spherical amorphous silica. Note that the average particle density of crystalline silica powder can be measured by the following method.
  • the crystalline silica powder contained in the inorganic powder according to this embodiment may be surface-treated with a surface-treating agent.
  • a surface-treating agent By surface-treating with a surface-treating agent, the filling properties of the inorganic powder according to the present embodiment into the resin tend to be better.
  • the surface treatment agent include silane coupling agents, aluminate coupling agents, and the like. These may be used alone or in combination of two or more. Note that the presence or absence of surface treatment of the crystalline silica powder contained in the inorganic powder can be confirmed by analyzing the crystalline silica powder using, for example, IR, TG-DTA, mass spectrometry, or the like.
  • the average circularity of the inorganic powder according to this embodiment is preferably 0.80 or more, more preferably 0.85 or more, and even more preferably 0.90 or more. If the average circularity of the inorganic powder is 0.80 or more, the filling properties and dispersibility into the resin are likely to be improved. Note that the average circularity of the inorganic powder can be measured by the same method as the above-mentioned crystalline silica powder.
  • the average particle diameter (D50) of the inorganic powder according to this embodiment is preferably 100 ⁇ m or less from the viewpoint of ease of adjustment and fluidity. In one embodiment, the average particle diameter (D50) is more preferably 1 to 100 ⁇ m, even more preferably 2 to 90 ⁇ m, and particularly preferably 3 to 80 ⁇ m.
  • the average particle diameter (D50) of the inorganic powder can be measured by the same method as for the crystalline silica powder described above.
  • the maximum value of the coefficient of thermal expansion (CTE max ) calculated from the TMA curve of the inorganic powder according to the present embodiment is preferably 40 ⁇ 10 ⁇ 5 /K or less, more preferably 35 ⁇ 10 ⁇ 5 /K or less, More preferably, it is 31 ⁇ 10 ⁇ 5 /K or less. Note that CTE max can be measured and calculated under the following conditions.
  • the temperature increase condition was 5°C/min, the measurement temperature was -10°C to 300°C, and the measurement was carried out for 2 cycles in a nitrogen atmosphere. From the 2nd cycle of the obtained TMA measurement chart, the temperature was increased by 10°C in the temperature range of 170 to 270°C.
  • the coefficient of thermal expansion is calculated for each time, and its maximum value is defined as CTE max . Further, among the coefficients of thermal expansion calculated using a similar method, the minimum value can be set as CTE min .
  • CTE max and CTE min are preferably calculated from the position where the slope is the largest and the position where the slope is the smallest when the thermal expansion coefficient is calculated every 10 degrees Celsius in the temperature range of 170 to 270 degrees Celsius of the TMA curve. .
  • the thermal expansion coefficient due to the ⁇ - ⁇ phase transition may be The coefficient of thermal expansion may be calculated by changing the range to include all the fluctuations in the expansion coefficient (for example, changing it not every 10 degrees Celsius, but every 5 degrees Celsius, every 7 degrees Celsius, every 15 degrees Celsius, etc.), Alternatively, the thermal expansion coefficient may be calculated for each 10° C. by shifting the temperature range back and forth. When shifting the temperature range forward or backward, it can be adjusted within the range of ⁇ 5 to 20°C.
  • the difference between CTE max and CTE min of the inorganic powder (CTE max - CTE min ) calculated by the above method may be 5.0 ⁇ 10 ⁇ 5 to 20 ⁇ 10 ⁇ 5 /K. , 7.0 ⁇ 10 ⁇ 5 to 20 ⁇ 10 ⁇ 5 /K.
  • the average crystallization rate of the inorganic powder (the average value of the crystallization rate of the crystalline silica powder contained in the inorganic powder) may be 60 to 90% by mass, and may be 65 to 90% by mass. Good too. Further, the average value of the ratio of the ⁇ -cristobalite phase in the inorganic powder (the average value of the ⁇ -cristobalite phase in the crystalline silica powder contained in the inorganic powder) may be 60 to 90% by mass, or 61 to 88% by mass. It may be %.
  • the inorganic powder according to the present embodiment may contain components other than the above-mentioned crystalline silica powder (other components).
  • the inorganic powder according to the present embodiment contains at least one metal component selected from alkali metals, alkaline earth metals, first transition elements, aluminum, magnesium, yttrium, and lanthanum in total (in terms of atoms). It may contain 100 ppm or more.
  • the metal component contained in the inorganic powder may be added at the time of manufacturing the crystalline silica powder.
  • controlling the firing temperature makes it easier to obtain the crystalline silica powder having the desired ⁇ -cristobalite phase ratio.
  • the other components are preferably at least two selected from aluminum, zinc, titanium, iron, manganese, calcium, strontium, barium, and titanium, and at least one selected from aluminum, titanium, strontium, and calcium. It is particularly preferable to include. Further, the total amount of other components is more preferably 100 to 30,000 ppm, and even more preferably 500 to 10,000 ppm. The amount of other components in the inorganic powder can be estimated based on the raw materials, and can be calculated more accurately by elemental analysis such as ICP emission spectrometry.
  • the method for producing inorganic powder according to the present embodiment includes mixing at least two types of crystalline silica powders having different ⁇ - ⁇ phase transition initiation temperatures (step (i)).
  • the at least two types of crystalline silica powders mixed in step (i) each have an ⁇ -cristobalite phase relative to the total amount (100% by mass) of the crystalline phase and the amorphous phase. The proportion is 30% by mass or more.
  • the method for producing an inorganic powder according to the present embodiment may include preparing at least two types of crystalline silica powders having different ⁇ - ⁇ phase transition start temperatures (step (i')). Details of the manufacturing method including step (i') and step (i) will be described below.
  • the method for producing an inorganic powder in this embodiment may include a step (i') of preparing at least two types of crystalline silica powders having different ⁇ - ⁇ phase transition start temperatures. At least two types of crystalline silica powders having different ⁇ - ⁇ phase transition initiation temperatures are selected from, for example, spherical silica powder, alkali metals, alkaline earth metals, first transition elements, aluminum, magnesium, yttrium, and lanthanum. It can be prepared by adding an additive containing at least one metal and firing. As the spherical silica powder, one prepared by a conventionally known method can be used. From the viewpoint of productivity, those prepared by a powder melting method are preferable. In this embodiment, step (i') may include a step of preparing spherical silica powder by a powder melting method.
  • step (i') may be a step of preparing at least two types of crystalline silica powders having different ⁇ - ⁇ phase transition initiation temperatures from amorphous spherical silica powder.
  • amorphous spherical silica powder refers to spherical silica powder with a silica (SiO 2 ) purity of 98% or more and an amorphous phase of 95% by mass or more of the total. means.
  • crushed materials such as silica sand and silica stone (hereinafter sometimes referred to as "crude raw materials”) are heated under high temperature conditions above the melting point of the raw materials using a flame, plasma, electric furnace, gas furnace, etc.
  • the melting atmosphere is not particularly limited, but from an economical point of view, it is preferable to carry out the melting under an air atmosphere.
  • the average particle diameter (D50) of the crude raw material is preferably 0.1 to 100 ⁇ m, more preferably 0.2 to 50 ⁇ m, and even more preferably 0.3 to 10 ⁇ m.
  • the average particle diameter (D50) of the spherical silica powder is preferably 1 to 100 ⁇ m, from the viewpoint of easy adjustment of multiple cristobalite particles with different half widths and crystallinity rates under the same firing conditions (firing temperature, firing time), and 1 to 100 ⁇ m. 80 ⁇ m is more preferable.
  • the average circularity is preferably 0.80 or more from the viewpoint of easily adjusting the average circularity of the finally obtained inorganic powder to 0.80 or more.
  • the additive added to the spherical silica powder contains at least one metal selected from alkali metals, alkaline earth metals, first transition elements, aluminum, magnesium, yttrium, and lanthanum. Among these, at least two selected from aluminum, zinc, titanium, iron, manganese, calcium, strontium, barium, and titanium are preferred. Examples of the additive include these pure metals; metal compounds such as oxides and hydroxides; and metal salts.
  • zinc oxide, titanium oxide, magnesium oxide, aluminum oxide, calcium carbonate, calcium hydroxide, strontium carbonate, strontium hydroxide, barium carbonate, barium hydroxide, strontium titanate, barium titanate, aluminum magnesium tetroxide is preferred, and more preferably contains at least one selected from aluminum oxide, calcium carbonate, titanium oxide, strontium carbonate, and strontium titanate.
  • the amount of the additive added is preferably 0.01 to 10 mol, more preferably 0.1 to 10 mol, even more preferably 0.1 to 7 mol, and even more preferably 0.5 to 7 mol, per 100 mol of crystalline silica powder. Particularly preferred is 5 mol.
  • the firing temperature is preferably 1000 to 1650°C, more preferably 1200 to 1600°C, and even more preferably 1300 to 1500°C, from the viewpoint of easily obtaining a plurality of crystalline silica powders having different half widths and crystallization rates.
  • the firing time is preferably 1 to 24 hours, more preferably 3 to 15 hours, and even more preferably 4 to 12 hours, from the viewpoint of cristobalite formation and productivity.
  • step (i') crystalline silica powder
  • the crystallization rate of , the proportion of ⁇ -cristobalite phase, and the ⁇ - ⁇ phase transition initiation temperature can be adjusted. For example, by setting the firing temperature to 1000 to 1650°C, crystalline silica powder having a crystallinity of 30% by mass or more, preferably 50% by mass or more may be obtained.
  • the ratio of the ⁇ -cristobalite phase to the total amount (100 mass%) of the crystalline phase and the amorphous phase is 30% by mass or more, preferably 50% by mass or more. Crystalline silica powder may be obtained.
  • crystalline silica powder having an ⁇ - ⁇ phase transition starting temperature of 170 to 280°C may be obtained by setting the firing temperature to 1200 to 1650°C.
  • crystalline silica powder with a narrow half width may be obtained by adding aluminum oxide in an amount of 1 mole or less per 100 moles of spherical silica powder as a raw material. Further, by setting the amount added to more than 1 mol, a crystalline silica powder having a wide half width may be obtained. When the half width is adjusted narrowly, the TMA curve of the crystalline silica powder tends to exhibit very strong thermal expansion behavior in a narrow temperature range.
  • the DSC curve of the obtained crystalline silica powder tends to have multiple endothermic peaks associated with ⁇ - ⁇ phase transition in a wide temperature range.
  • Inorganic powder containing such crystalline silica powder tends to have a TMA curve showing mild thermal expansion behavior, and also tends to have a low coefficient of thermal expansion.
  • crystalline silica powder with a narrow half-value width may be obtained by adding strontium titanate in an amount of 1 mol or less, preferably 0.5 mol or less, per 100 mol of spherical silica powder as a raw material. . Further, by setting the amount added to more than 1 mol, a crystalline silica powder having a wide half width may be obtained.
  • the crystallization rate can be increased to 30% by mass or more, preferably 50% by mass. % or more of crystalline silica powder may be obtained at the same time.
  • Step (i) is a step of mixing at least two types of crystalline silica powders having different ⁇ - ⁇ phase transition initiation temperatures.
  • a method for mixing the crystalline silica powder conventionally known methods such as a powder mixer, mixer, etc. can be employed.
  • mixing conditions for example, mixing may be performed at room temperature for 1 to 60 minutes.
  • step (i) may be a step of mixing at least two types of crystalline silica powders having an ⁇ - ⁇ phase transition initiation temperature of 170 to 280°C.
  • the average particle diameter (D50) of the plurality of crystalline silica powders to be mixed is 100 ⁇ m or less, the particle diameters may be the same or may be different. From the viewpoint of fluidity during resin compounding, it is preferable to mix a plurality of crystalline silica powders having different average particle diameters (D50).
  • the inorganic powder according to the present embodiment can be prepared by the method including the above-mentioned step (i) (if necessary, by the method including step (i') and step (i)). Note that after step (i), the inorganic powder may be surface-treated with a surface-treating agent, if necessary.
  • the inorganic powder according to this embodiment has a lower coefficient of thermal expansion than conventional cristobalite powder, and can achieve a high coefficient of thermal expansion. Therefore, the inorganic powder according to this embodiment can be filled into a resin and used as a filler for a sealing material.
  • a resin composition containing an inorganic powder according to this embodiment will be explained.
  • the resin composition according to this embodiment includes the above-mentioned inorganic powder and at least one resin selected from thermoplastic resins and thermosetting resins.
  • the content of inorganic powder in the resin composition is not particularly limited and can be adjusted as appropriate depending on the purpose.
  • the proportion of inorganic powder in the resin composition is preferably 40 to 90% by mass, more preferably 70 to 90% by mass, based on the total mass of the resin composition. preferable.
  • the resin composition according to this embodiment includes at least one resin selected from thermoplastic resins and thermosetting resins.
  • the thermoplastic resin include polyethylene resin; polypropylene resin, and the like.
  • thermosetting resins include epoxy resins; silicone resins; phenolic resins; melamine resins; urea resins; unsaturated polyester resins; fluororesins; polyamide resins such as polyimide resins, polyamideimide resins, and polyetherimide resins; Polyester resins such as butylene terephthalate resin and polyethylene terephthalate resin; polyphenylene sulfide resin; wholly aromatic polyester resin; polysulfone resin; liquid crystal polymer resin; polyether sulfone resin; polycarbonate resin; maleimide modified resin; ABS resin; AAS (acrylonitrile-acrylic Examples include rubber-styrene resin; AES (acrylonitrile-ethylene-propylene-diene rubber-styrene) resin; hydrocarbon elastomer
  • Epoxy resins are not particularly limited, and include, for example, phenol novolac type epoxy resins, orthocresol novolac type epoxy resins, epoxidized novolak resins of phenols and aldehydes, and glycidyl resins such as bisphenol A, bisphenol F, and bisphenol S.
  • Ether type epoxy resin glycidyl ester acid epoxy resin (bisphenol type epoxy resin) obtained by reaction of polybasic acid such as phthalic acid or dimer acid with epochlorohydrin, linear aliphatic epoxy resin, alicyclic epoxy resin , heterocyclic epoxy resin, alkyl-modified polyfunctional epoxy resin, ⁇ -naphthol novolac type epoxy resin, 1,6-dihydroxynaphthalene type epoxy resin, 2,7-dihydroxynaphthalene type epoxy resin, bishydroxybiphenyl type epoxy resin, Examples include epoxy resins into which halogens such as bromine are introduced to impart flammability. These may be used alone or in combination of two or more. Among these, it is more preferable to include at least one epoxy resin selected from glycidyl ether type epoxy resins such as bisphenol A and bisphenol F, and alicyclic epoxy resins.
  • bisphenol type epoxy resin bisphenol type epoxy resin obtained by reaction of polybasic acid such as phthalic acid or dim
  • the resin composition When containing an epoxy resin as the resin, it is preferable that the resin composition further contains a curing agent.
  • a curing agent for example, at least one selected from the group of phenol, cresol, xylenol, resorcinol, chlorophenol, t-butylphenol, nonylphenol, isopropylphenol, octylphenol, etc., is used together with formaldehyde, paraformaldehyde, or paraxylene as an oxidation catalyst.
  • Novolac type resin obtained by the reaction below, polyparahydroxystyrene resin, bisphenol compounds such as bisphenol A and bisphenol S, trifunctional phenols such as pyrogallol and phloroglucinol, maleic anhydride, phthalic anhydride, and pyromellitic anhydride.
  • examples include acid anhydrides such as acids, aromatic amines such as metaphenylene diamine, diaminodiphenylmethane, and diaminodiphenylsulfone. These curing agents may be used alone or in combination of two or more.
  • the content of the curing agent is preferably blended so that the active hydrogen equivalent (or acid anhydride equivalent) of the curing agent is 0.01 to 1.25 per 1 epoxy equivalent of the epoxy resin.
  • the resin composition may contain a curing accelerator, a mold release agent, a coupling agent, a coloring agent, etc. within a range that does not impede the effects of the present invention.
  • the curing accelerator is not particularly limited, and examples thereof include 1,8-diazabicyclo(5,4,0)undecene-7, triphenylphosphine, benzyldimethylamine, 2-methylimidazole, and the like.
  • the mold release agent include natural waxes, synthetic waxes, metal salts of straight chain fatty acids, acid amides, esters, paraffin, and the like.
  • the coupling agent include silane coupling agents.
  • silane coupling agent examples include epoxysilanes such as ⁇ -glycidoxypropyltrimethoxysilane and ⁇ -(3,4-epoxycyclohexyl)ethyltrimethoxysilane; aminopropyltriethoxysilane, ureidopropyltriethoxysilane, Aminosilanes such as N-phenylaminopropyltrimethoxysilane; hydrophobic silane compounds such as phenyltrimethoxysilane, methyltrimethoxysilane, octadecyltrimethoxysilane, and mercaptosilane.
  • epoxysilanes such as ⁇ -glycidoxypropyltrimethoxysilane and ⁇ -(3,4-epoxycyclohexyl)ethyltrimethoxysilane
  • the method for producing the resin composition according to the present embodiment is not particularly limited, and can be produced by stirring, dissolving, mixing, or dispersing predetermined amounts of each material.
  • Apparatus for mixing, stirring, dispersing, etc. these mixtures is not particularly limited, but a Raikai machine equipped with a stirring and heating device, a three-roll mill, a ball mill, a planetary mixer, etc. can be used. Further, these devices may be used in appropriate combination.
  • the resin composition according to the present embodiment contains an inorganic powder that does not exhibit thermal expansion behavior like conventional spherical cristobalite powder and has a high coefficient of thermal expansion. Therefore, when the resin composition according to this embodiment is used as a sealing material, it is easier to handle and it is possible to prevent warping and cracking of the semiconductor device. Furthermore, the resin composition according to the present embodiment has low viscosity and therefore has good fluidity and excellent moldability.
  • DSC measurement of crystalline silica powder 50 mg of crystalline silica powder was heated in an air atmosphere (purge: Air) using a differential scanning calorimeter (manufactured by Netch Japan Co., Ltd., product name "STA449F3 Jupiter (registered trademark)" at a heating rate of 10° C./min.
  • a DSC curve was obtained by heating the crystalline silica powder from room temperature to 300° C. (50 mL/min, protective: N 2 20 mL/min).
  • phase transition of cristobalite appears as an endothermic peak, as shown in Figure 2, draw a line L1 along the slope of the baseline of the starting temperature of the endothermic peak in the DSC curve, and then draw the line L1 at the first inflection point of the endothermic peak.
  • the temperature at the point of intersection (starting point 1) with the line drawn along the line was defined as the " ⁇ - ⁇ phase transition starting temperature.” Note that the ⁇ - ⁇ phase transition end temperature and the ⁇ - ⁇ phase transition peak top temperature were also determined from the obtained DSC curve.
  • the " ⁇ - ⁇ phase transition end temperature” is calculated by drawing a line L2 along the slope of the baseline of the end temperature of the DSC curve, and then drawing it along the last inflection point of the endothermic peak. It was determined from the intersection with the line (end point 2). Further, the " ⁇ - ⁇ phase transition peak top temperature” was determined from the peak top temperature of the endothermic peak.
  • Method of measuring specific surface area Fill a measuring cell with 1 g of crystalline silica powder, and use a fully automatic specific surface area diameter measuring device (manufactured by Mountech, product name: Macsorb HM model-1201 (BET-point method)) to measure the ratio of crystalline silica powder. Surface area was measured. Note that the degassing conditions before measurement were 200° C. and 10 minutes.
  • the average particle diameter was measured using a laser diffraction particle size distribution analyzer (manufactured by Beckman Coulter, trade name: LS 13 320). First, 50 cm 3 of pure water and 0.1 g of crystalline silica powder were placed in a glass beaker, and dispersed for 1 minute using an ultrasonic homogenizer (trade name: SFX250, manufactured by BRANSON). The dispersion of crystalline silica powder subjected to the dispersion treatment was added drop by drop to a laser diffraction type particle size distribution measuring device using a dropper, and measurements were performed 30 seconds after adding a predetermined amount.
  • a laser diffraction particle size distribution analyzer manufactured by Beckman Coulter, trade name: LS 13 320.
  • the particle size distribution was calculated from the data of the light intensity distribution of the diffraction/scattered light of the crystalline silica powder detected by the sensor in the laser diffraction type particle size distribution measuring device.
  • the average particle diameter was calculated from the particle diameter corresponding to a cumulative value of 50% in the volume-based cumulative particle size distribution of the measured particle diameter.
  • Crystalline silica powders 2 to 12 were prepared in the same manner as crystalline silica powder 1, except that the additives added to the amorphous spherical silica powder, the firing temperature, and the firing time were as shown in Table 1.
  • crystalline silica powders 7 to 9 amorphous spherical silica powder manufactured by Denka Co., Ltd. under the product name "FB-5D" (average particle diameter (D50): 4.7 ⁇ m) was used.
  • Examples 1 to 8 Inorganic powder was prepared by mixing crystalline silica powder in the formulation shown in Table 2. As for mixing conditions, each powder was placed in a plastic container and mixed for 3 minutes at room temperature using a low frequency resonance acoustic mixer (manufactured by Resodyn). Regarding the inorganic powder of each example, the coefficient of thermal expansion, coefficient of thermal expansion, and half-width of the (101) plane of the ⁇ -cristobalite phase were measured under the following conditions. In addition, the average particle diameter, average circularity, specific surface area, and particle density were measured under the same conditions as for crystalline silica powder. The results are shown in Table 2.
  • TMA analysis 20.0 parts by mass of epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name "JER828”) and 5.0 parts by mass of 4,4'-diaminodiphenylmethane were mixed while melting at 95°C, and the inorganic powder was converted to volume %. and mixed with a planetary stirrer (rotation speed: 2000 rpm).
  • the above mixture was poured into a preheated silicone mold (2 cm square x 5 mm thick), left to stand at 80°C for 20 minutes, and then heated using a vacuum heat press (manufactured by Imoto Seisakusho Co., Ltd., product name "IMC-").
  • the temperature increase condition was 5°C/min
  • the measurement temperature was -10°C to 300°C
  • the measurement was carried out for 2 cycles in a nitrogen atmosphere, and from the 2nd cycle of the obtained TMA measurement chart, in the temperature range of 170 to 270°C, 10
  • the thermal expansion coefficient was calculated for each °C. Further, the maximum value was defined as CTE max , and the minimum value was defined as CTE min .
  • the thermal expansion coefficient in the temperature range of 170 to 270° C. was calculated from the TMA curve obtained from the above TMA measurement.
  • Inorganic powders were prepared using the formulations shown in Table 2 under the same conditions as in the examples. Regarding the obtained inorganic powder, the thermal expansion coefficient and the half-value width of the (101) plane of the ⁇ -cristobalite phase were measured under the same conditions as in the examples. In addition, the average particle diameter, average circularity, specific surface area, and particle density were measured under the same conditions as for crystalline silica powder. The results are shown in Table 3.
  • the maximum value (CTE max ) of the coefficient of thermal expansion of the spherical cristobalite powder of Comparative Example 3 calculated by the above method is 49.7 ⁇ 10 ⁇ 5 /K, and the difference (CTE max - CTE min ) was 38.0 ⁇ 10 ⁇ 5 /K. Therefore, for the inorganic powder obtained in each example, the difference (CTE max - CTE min ) was calculated and evaluated using the following evaluation criteria. The results are shown in Tables 2 and 3. (Evaluation criteria) Excellent (3 points): (CTE max ) was 40 ⁇ 10 ⁇ 5 /K or less, and (CTE max ⁇ CTE min ) was 15 ⁇ 10 ⁇ 5 /K or less.
  • (CTE max ) was 40 ⁇ 10 ⁇ 5 /K or less, and (CTE max ⁇ CTE min ) was more than 15 ⁇ 10 ⁇ 5 /K and 25 ⁇ 10 ⁇ 5 /K or less.
  • the powder exhibits a coefficient of thermal expansion comparable to that of spherical cristobalite powder.
  • the coefficient of thermal expansion (170 to 270°C) of the spherical cristobalite powder of Comparative Example 3 was 1573.9 ( ⁇ 10 ⁇ 5 ).
  • the thermal expansion coefficients (170 to 270°C) of the spherical amorphous silica powder of Comparative Example 4 and the crushed quartz powder of Comparative Example 5 are 1012.7 ( ⁇ 10 ⁇ 5 ) and 1111.7 ( ⁇ 10 -5 ), the coefficient of thermal expansion (170 to 270°C) of the inorganic powder of each example was evaluated using the following evaluation criteria. The results are shown in Tables 2 and 3. (Evaluation criteria) Excellent (3 points): The coefficient of thermal expansion (170 to 270°C) was 1550 ( ⁇ 10 ⁇ 5 ) or more.
  • Calcium carbonate (CaCO 3 ) Manufactured by Ube Materials Co., Ltd., product name “CS 3N-A”.
  • Aluminum oxide (Al 2 O 3 ) manufactured by Nippon Aerosil Co., Ltd., product name “Alu-C”.
  • Zinc oxide (ZnO) Manufactured by Hakusuitec Co., Ltd., product name: "Zinc oxide type 2".
  • Magnesium oxide (MgO) manufactured by Sakai Chemical Industry Co., Ltd., product name "SMO-0.1”.
  • Barium hydroxide octahydrate (Ba(OH) 2.8H 2 O): manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., product name "Barium hydroxide octahydrate”.
  • Barium titanate (BaTiO 3 ): manufactured by Kyoritsu Materials Co., Ltd., product name “BT-SA”.
  • Amorphous spherical silica powder manufactured by Denka Co., Ltd., product name "FR-40R” (raw material for crystalline silica powders 1 to 6 and 10 to 12).
  • Amorphous spherical silica powder manufactured by Denka Co., Ltd., product name "FB-5D” (raw material for crystalline silica powders 7 to 9).
  • Crushed quartz manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., product name "silicon dioxide”, crystallization rate: 100% by mass, proportion of quartz in crystal phase: 100% by mass.
  • FIG. 4 is a TMA curve of the inorganic powder of Example 1.
  • the inorganic powder of the example that satisfies the configuration of this embodiment did not have a rapid rise in the coefficient of thermal expansion in the TMA analysis, and had a lower coefficient of thermal expansion than the spherical cristobalite powder of Comparative Example 3.
  • the coefficient of thermal expansion (170 to 270° C.) was higher than that of the spherical amorphous silica powder and crushed quartz powder of Comparative Examples 4 and 5, and had a value comparable to that of the spherical cristobalite powder of Comparative Example 3.
  • the inorganic powders of Examples 2 to 8 also had low coefficients of thermal expansion and were able to achieve high coefficients of thermal expansion.
  • the inorganic powder of Comparative Example 1 whose half width was smaller than the range of this embodiment had a coefficient of thermal expansion comparable to that of the spherical cristobalite powder of Comparative Example 3, and the ⁇ - ⁇ phase transition of cristobalite The thermal expansion behavior associated with this process could not be controlled.
  • the inorganic powder of Comparative Example 2 whose half width was larger than the range of this embodiment, although the coefficient of thermal expansion was smaller than that of Comparative Example 3, a high coefficient of thermal expansion could not be achieved.
  • the inorganic powder and the manufacturing method thereof according to the present embodiment can provide an inorganic powder that has a lower coefficient of thermal expansion than conventional cristobalite powder and can achieve a high coefficient of thermal expansion.
  • the resin composition according to this embodiment containing such an inorganic powder can be suitably used as a filler for a sealing material.
  • the inorganic powder and the method for producing the same according to the present embodiment can provide an inorganic powder that has a lower coefficient of thermal expansion than conventional cristobalite powder and can achieve a high coefficient of thermal expansion.
  • the resin composition according to this embodiment containing such an inorganic powder can be suitably used as a filler for a sealing material.

Abstract

Provided are: an inorganic powder which has a lower coefficient of thermal expansion than conventional cristobalite powders and can attain a high degree of thermal expansion; a method for producing the inorganic powder; and a resin composition containing the inorganic powder.　The inorganic powder comprises at least two crystalline-silica powders which differ in α-β phase transition initiation temperature and in each of which the proportion of an α-cristobalite phase is 30 mass% or higher with respect to the total amount (100 mass%) of the crystalline phase and the amorphous phase. The inorganic powder has an X-ray diffraction peak assigned to the (101) plane of the α-cristobalite phase, the X-ray diffraction peak having a full width at half maximum (FWHM) of 0.120-0.300°.

Description

無機粉末及びその製造方法、並びに樹脂組成物Inorganic powder and its manufacturing method, and resin composition
　本発明は、無機粉末及びその製造方法、並びに樹脂組成物に関する。 The present invention relates to an inorganic powder, a method for producing the same, and a resin composition.
　シリカや酸化チタン等の無機粉末は樹脂フィラーとして知られており、例えば、半導体素子の封止材用のフィラーとして用いられている。このうちシリカ粉末は、天然から珪石として産出される無機化合物であり、汎用性の高いフィラーである。 Inorganic powders such as silica and titanium oxide are known as resin fillers, and are used, for example, as fillers for sealing materials for semiconductor devices. Among these, silica powder is an inorganic compound naturally produced as silica stone, and is a highly versatile filler.
　シリカ粉末をフィラーとして用いる場合、樹脂への分散性を向上させる観点から、球状シリカ粉末が広く使用されている。球状シリカ粉末は一般に非晶質であり、熱膨張率及び熱伝導率が低い。非晶質シリカ粉末の熱膨張率は０．５ｐｐｍ／Ｋであり、熱伝導率は１．４Ｗ／ｍＫである。熱膨張率の低い非晶質シリカ粉末を封止材用フィラーとして用いた場合、リフロー時や半導体デバイスの作動時に、反りやクラックが生じることがある。また、熱伝導率が低いことにより、半導体デバイスから発生する熱を放散しにくいという問題もある。 When using silica powder as a filler, spherical silica powder is widely used from the viewpoint of improving dispersibility in resin. Spherical silica powder is generally amorphous and has a low coefficient of thermal expansion and low thermal conductivity. The thermal expansion coefficient of the amorphous silica powder is 0.5 ppm/K, and the thermal conductivity is 1.4 W/mK. When amorphous silica powder with a low coefficient of thermal expansion is used as a filler for a sealant, warping or cracking may occur during reflow or during operation of a semiconductor device. Another problem is that it is difficult to dissipate heat generated from semiconductor devices due to low thermal conductivity.
　ところで、クリストバライト、α－石英相、トリジマイト相等の結晶構造を有する結晶質シリカ粉末は、非晶質シリカ粉末よりも熱膨張率及び熱伝導率が高いことが知られている。そのため、非晶質シリカ粉末を結晶化して熱膨張率を高める方法について検討されている（特許文献１、２等）。 Incidentally, it is known that crystalline silica powder having a crystal structure such as cristobalite, α-quartz phase, or tridymite phase has a higher coefficient of thermal expansion and thermal conductivity than amorphous silica powder. Therefore, methods of increasing the coefficient of thermal expansion by crystallizing amorphous silica powder have been studied (Patent Documents 1, 2, etc.).
　結晶質シリカ粉末の中でも、特にクリストバライト結晶相の割合の高い結晶質シリカ粉末（以下、「クリストバライト粉末」と記載する）は、その他の結晶構造を有する結晶質シリカ粉末よりも高い熱膨張率を有している。クリストバライト粉末の熱膨張率は約１７～３６ｐｐｍ／Ｋであり、高熱膨張率を達成可能なフィラーとして種々の検討がなされている。例えば、特許文献３には、クリストバライト結晶相を一定量含む結晶質シリカ粉末を配合した封止材用樹脂組成物が提案されている。また特許文献４には、封止材用フィラーとして適用可能な、クリストバライト結晶相を含む球状結晶質シリカ粉末を低コストで製造する方法について記載されている。 Among crystalline silica powders, crystalline silica powders with a particularly high proportion of cristobalite crystal phase (hereinafter referred to as "cristobalite powders") have a higher coefficient of thermal expansion than crystalline silica powders with other crystal structures. are doing. The thermal expansion coefficient of cristobalite powder is approximately 17 to 36 ppm/K, and various studies have been made as a filler capable of achieving a high thermal expansion coefficient. For example, Patent Document 3 proposes a resin composition for an encapsulant containing crystalline silica powder containing a certain amount of cristobalite crystal phase. Further, Patent Document 4 describes a method for manufacturing at low cost a spherical crystalline silica powder containing a cristobalite crystal phase, which can be applied as a filler for an encapsulant.
特開２０１２－１０２０１６号公報Japanese Patent Application Publication No. 2012-102016 特開平１０－２５１０４２号公報Japanese Patent Application Publication No. 10-251042 特開２０２１－１５５７３１号公報Japanese Patent Application Publication No. 2021-155731 国際公開第２０１６／０３１８２３号International Publication No. 2016/031823
　ところで、クリストバライト粉末を加熱すると、２２０～２８０℃の特定の温度範囲で、クリストバライトの結晶構造がα相からβ相に相転移する。α相からβ相に相転移する際、結晶構造の変化に伴って体積膨張するため、熱膨張率が急激に変化する。クリストバライト粉末を封止材用フィラーとして用いる場合、相転移開始温度がリフロー時の加熱温度と重複していることから、半田溶融時に相転移に伴う熱膨張挙動により、封止材と基板の界面でクラックや割れが生じる場合があり、非常に扱いづらいという問題がある。すなわち、封止材用途に用いられる無機粉末としては、リフロー時や半導体デバイスの作動時に反りやクラックが発生しにくいという観点からは、高熱膨張率の結晶質シリカ粉末が好まれるが、高熱膨張率を達成可能なクリストバライト粉末は、クリストバライトの相転移に伴う特異的な熱膨張挙動を示すため、半田溶融時に基板と封止材との界面でクラックや割れが生じやすいという問題を有している。これらの観点から、リフロー時の加熱温度でも熱膨張率の急激な上昇が生じず、かつ高熱膨張率を達成可能なフィラーが求められている。 By the way, when cristobalite powder is heated, the crystal structure of cristobalite undergoes a phase transition from α phase to β phase in a specific temperature range of 220 to 280°C. During the phase transition from α phase to β phase, the volume expands as the crystal structure changes, resulting in a rapid change in the coefficient of thermal expansion. When cristobalite powder is used as a filler for encapsulant, the phase transition start temperature overlaps with the heating temperature during reflow, so the thermal expansion behavior accompanying the phase transition during solder melting causes the interface between the encapsulant and the substrate to Cracks and cracks may occur, making it extremely difficult to handle. In other words, as an inorganic powder used for encapsulant applications, crystalline silica powder with a high coefficient of thermal expansion is preferred from the viewpoint of being less likely to cause warping or cracking during reflow or during the operation of semiconductor devices; The cristobalite powder that can achieve this has a problem in that it tends to crack or break at the interface between the substrate and the sealant when melting solder because it exhibits specific thermal expansion behavior associated with the phase transition of cristobalite. From these viewpoints, there is a need for a filler that does not cause a sudden increase in the coefficient of thermal expansion even at heating temperatures during reflow and can achieve a high coefficient of thermal expansion.
　結晶質シリカ粉末の熱膨張挙動は、熱機械分析（Ｔｈｅｒｍｏｍｅｃｈａｎｉｃａｌ　Ａｎａｌｙｓｉｓ；ＴＭＡ）により確認することができる。一般的なクリストバライト粉末のＴＭＡ分析では、α相からβ相への相転移時に、狭い温度領域で熱膨張率の急激な立ち上がりが生じることが分かる。そのため、クリストバライト粉末は熱膨張係数が非常に大きくなる。「熱膨張係数」とは、粉末の体積膨張又は体積収縮の割合を１℃当たりで表した値であり、熱膨張係数が非常に大きいクリストバライト粉末は、前述の通り、封止材と基板の界面でクラックや割れが生じやすいため、ハンドリング性が悪い。 The thermal expansion behavior of crystalline silica powder can be confirmed by thermomechanical analysis (TMA). TMA analysis of a typical cristobalite powder shows that the coefficient of thermal expansion rapidly rises in a narrow temperature range during phase transition from α phase to β phase. Therefore, cristobalite powder has a very large coefficient of thermal expansion. "Thermal expansion coefficient" is a value that expresses the rate of volumetric expansion or volumetric contraction of powder per 1°C, and as mentioned above, cristobalite powder, which has a very large coefficient of thermal expansion, is used at the interface between the sealing material and the substrate. It is easy to crack and break, making it difficult to handle.
　そこで本発明は、従来のクリストバライト粉末よりも低い熱膨張係数を有し、かつ高熱膨張率を達成できる無機粉末及びその製造方法、並びに前記無機粉末を含む樹脂組成物を提供することを目的とする。 Therefore, an object of the present invention is to provide an inorganic powder that has a lower coefficient of thermal expansion than conventional cristobalite powder and can achieve a high coefficient of thermal expansion, a method for producing the same, and a resin composition containing the inorganic powder. .
　本発明者らは鋭意検討した結果、α－クリストバライト相を３０質量％以上含む結晶質シリカ粉末のうち、α－β相転移開始温度の異なる結晶質シリカ粉末を２種類以上含み、かつＸ線回折ピークにおける、α－クリストバライト相の半値幅が一定の範囲内にある無機粉末であれば、上述の全ての課題を解決できることを見出し、本発明を完成させるに至った。
　すなわち、本発明は以下の態様を有する。
［１］無機粉末であって、前記無機粉末は、α－β相転移開始温度が異なる少なくとも２種類の結晶質シリカ粉末を含み、前記少なくとも２種類の結晶質シリカ粉末は、いずれも、結晶相及び非晶質相の合計量（１００質量％）に対するα－クリストバライト相の割合が３０質量％以上であり、前記無機粉末のα－クリストバライト相の（１０１面）のＸ線回折ピークの半値幅（ＦＷＨＭ）が、０．１２０°～０．３００°である、無機粉末。
［２］前記無機粉末の平均円形度が０．８０以上である、［１］に記載の無機粉末。
［３］前記無機粉末の平均粒子径（Ｄ５０）が１００μｍ以下である、［１］または［２］に記載の無機粉末。
［４］α－β相転移開始温度が最も低い結晶質シリカ粉末（Ａ）のα－β相転移開始温度（ＴＡ）と、α－β相転移開始温度が最も高い結晶質シリカ粉末（Ｂ）のα－β相転移開始温度（ＴＢ）との差（ＴＢ－ＴＡ）が、９０℃以下である、［１］から［３］のいずれかに記載の無機粉末。
［５］前記α－β相転移開始温度（ＴＡ）が１７０～２５０℃であり、前記α－β相転移開始温度（ＴＢ）が２００～２８０℃である、［４］に記載の無機粉末。
［６］前記無機粉末のＴＭＡ曲線から算出される熱膨張係数の最大値（ＣＴＥｍａｘ）が、４０×１０－５／Ｋ以下である、［１］から［５］のいずれかに記載の無機粉末。
［７］［１］から［６］のいずれかに記載の無機粉末と、熱可塑性樹脂及び熱硬化性樹脂から選択される少なくとも１つの樹脂とを含む、樹脂組成物。
［８］封止材用である、［７］に記載の樹脂組成物。
［９］［１］から［６］のいずれかに記載の無機粉末の製造方法であって、α－β相転移開始温度が異なる少なくとも２種類の結晶質シリカ粉末を混合することを含み、前記少なくとも２種類の結晶質シリカ粉末は、いずれも、結晶相及び非晶質相の合計量（１００質量％）に対するα－クリストバライト相の割合が３０質量％以上である、無機粉末の製造方法。
［１０］前記少なくとも２種類の結晶質シリカ粉末が、１７０～２８０℃の範囲にα－β相転移開始温度を有する、［９］に記載の無機粉末の製造方法。 As a result of intensive studies, the present inventors found that among crystalline silica powders containing 30% by mass or more of an α-cristobalite phase, two or more types of crystalline silica powders having different α-β phase transition initiation temperatures and X-ray diffraction We have found that all of the above-mentioned problems can be solved if the inorganic powder has a peak half-width of the α-cristobalite phase within a certain range, and we have completed the present invention.
That is, the present invention has the following aspects.
[1] An inorganic powder, wherein the inorganic powder includes at least two types of crystalline silica powders having different α-β phase transition initiation temperatures, and each of the at least two types of crystalline silica powders has a crystalline phase. and the ratio of the α-cristobalite phase to the total amount (100 mass%) of the amorphous phase is 30% by mass or more, and the half-value width ( An inorganic powder having a FWHM) of 0.120° to 0.300°.
[2] The inorganic powder according to [1], wherein the inorganic powder has an average circularity of 0.80 or more.
[3] The inorganic powder according to [1] or [2], wherein the inorganic powder has an average particle diameter (D50) of 100 μm or less.
[4] α-β phase transition initiation temperature (TA) of crystalline silica powder (A) with the lowest α-β phase transition initiation temperature, and crystalline silica powder (B) with the highest α-β phase transition initiation temperature The inorganic powder according to any one of [1] to [3], wherein the difference (TB-TA) from the α-β phase transition starting temperature (TB) is 90° C. or less.
[5] The inorganic powder according to [4], wherein the α-β phase transition onset temperature (TA) is 170 to 250°C, and the α-β phase transition onset temperature (TB) is 200 to 280°C.
[6] The inorganic powder according to any one of [1] to [5], wherein the maximum value of the coefficient of thermal expansion (CTE max ) calculated from the TMA curve of the inorganic powder is 40×10 −5 /K or less. powder.
[7] A resin composition comprising the inorganic powder according to any one of [1] to [6] and at least one resin selected from thermoplastic resins and thermosetting resins.
[8] The resin composition according to [7], which is used as a sealing material.
[9] A method for producing an inorganic powder according to any one of [1] to [6], comprising mixing at least two types of crystalline silica powders having different α-β phase transition initiation temperatures, A method for producing an inorganic powder, wherein the at least two types of crystalline silica powder each have an α-cristobalite phase of 30% by mass or more relative to the total amount (100% by mass) of the crystalline phase and the amorphous phase.
[10] The method for producing an inorganic powder according to [9], wherein the at least two types of crystalline silica powders have an α-β phase transition initiation temperature in the range of 170 to 280°C.
　本発明によれば、従来のクリストバライト粉末よりも低い熱膨張係数を有し、かつ高熱膨張率を達成できる無機粉末及びその製造方法、並びに前記無機粉末を含む樹脂組成物を提供できる。 According to the present invention, it is possible to provide an inorganic powder that has a lower coefficient of thermal expansion than conventional cristobalite powder and can achieve a high coefficient of thermal expansion, a method for producing the same, and a resin composition containing the inorganic powder.
比較例３の球状クリストバライト粉末、比較例４の球状非晶質シリカ粉末、及び比較例５の破砕石英粉末のＴＭＡ曲線の一例である。2 is an example of TMA curves of spherical cristobalite powder of Comparative Example 3, spherical amorphous silica powder of Comparative Example 4, and crushed quartz powder of Comparative Example 5. α－β相転移開始温度の求め方を説明するためのＤＳＣ曲線の例である。This is an example of a DSC curve for explaining how to determine the α-β phase transition starting temperature. 実施例１の無機粉末のＤＳＣ曲線の一例である。1 is an example of a DSC curve of the inorganic powder of Example 1. 実施例１の無機粉末及び比較例３の球状クリストバライト粉末のＴＭＡ曲線の一例である。1 is an example of TMA curves of the inorganic powder of Example 1 and the spherical cristobalite powder of Comparative Example 3.
　以下、本発明の一実施形態について説明するが、本発明は以下の実施形態に限定されるものではない。なお、本明細書において「～」の記載は、「以上以下」を意味する。例えば、「２２０～２８０℃」とは、２２０℃以上２８０℃以下を意味する。また本明細書において「粉末」とは、「複数の粒子の集合体」を意味する。 Hereinafter, one embodiment of the present invention will be described, but the present invention is not limited to the following embodiment. In addition, in this specification, the description of "~" means "more than or less than". For example, "220 to 280°C" means 220°C or more and 280°C or less. Further, in this specification, "powder" means "aggregate of a plurality of particles".
［無機粉末］
　本実施形態に係る無機粉末は、α－β相転移開始温度が異なる少なくとも２種類の結晶質シリカ粉末を含み、前記少なくとも２種類の結晶質シリカ粉末は、いずれも、結晶相及び非晶質相の合計量（１００質量％）に対するα－クリストバライト相の割合が３０質量％以上であり、前記無機粉末のα－クリストバライト相の（１０１面）のＸ線回折ピークの半値幅（ＦＷＨＭ）が、０．１２０°～０．３００°であることを特徴とする。本実施形態に係る無機粉末によれば、従来のクリストバライト粉末よりも低い熱膨張係数を有し、かつ高熱膨張率を達成できる。「従来のクリストバライト粉末よりも低い熱膨張係数を有する」とは、クリストバライトのα相からβ相への相転移が生じる温度領域、より好ましくは１７０～２７０℃の温度領域における、後述の方法にて測定される熱膨張係数の最大値（ＣＴＥｍａｘ）が、一般的な球状クリストバライト粉末（結晶化率及びα－クリストバライト相の割合が９０質量％以上の球状クリストバライト粉末１種類のみからなる結晶質シリカ粉末）の熱膨張係数の最大値（５０×１０－５／Ｋ以上）よりも低いことを意味する。 [Inorganic powder]
The inorganic powder according to the present embodiment includes at least two types of crystalline silica powders having different α-β phase transition start temperatures, and each of the at least two types of crystalline silica powders has a crystalline phase and an amorphous phase. The ratio of the α-cristobalite phase to the total amount (100 mass%) of the inorganic powder is 30% by mass or more, and the half-width at half maximum (FWHM) of the (101 plane) It is characterized by being between .120° and 0.300°. According to the inorganic powder according to this embodiment, it has a lower coefficient of thermal expansion than conventional cristobalite powder and can achieve a high coefficient of thermal expansion. "Having a coefficient of thermal expansion lower than that of conventional cristobalite powder" means that the process is performed in a temperature range where cristobalite undergoes phase transition from α phase to β phase, more preferably in a temperature range of 170 to 270°C, by the method described below. The maximum value of the measured coefficient of thermal expansion (CTE max ) is a general spherical cristobalite powder (crystalline silica powder consisting of only one type of spherical cristobalite powder with a crystallinity rate and a proportion of α-cristobalite phase of 90% by mass or more) ) means lower than the maximum value of the thermal expansion coefficient (50×10 −5 /K or more).
　本実施形態に係る無機粉末において、α－クリストバライト相の（１０１面）のＸ線回折ピーク（ＸＲＤ）の半値幅（Ｆｕｌｌ　Ｗｉｄｔｈ　ｏｆ　Ｈａｌｆ　Ｍａｘｉｍｕｍ　ｉｎｔｅｎｓｉｔｙ：ＦＷＨＭ）（以下、単に「半値幅」と記載することもある）は、０．１２０°～０．３００°であり、０．１４０°～０．３００°が好ましく、０．１５０°～０．２６０°がより好ましい。半値幅が０．１２０°～０．３００°であることにより、無機粉末のα－β相転移温度を分散させることができ、局所的な熱膨張を示さず、樹脂に混ぜた際にα－β相転移に伴う熱膨張を緩和させる効果が得られる。それにより、熱膨張係数の低い結晶質シリカ粉末を得ることができる。なお、前記半値幅は以下の条件で測定することができる。
＜無機粉末のＸ線回折の測定方法＞
　ＸＲＤ装置（例えば、（株）リガク製、製品名「ＲＩＮＴ－ＵｌｔｉｍａＩＶ」）を用いて、以下の条件で無機粉末のＸ線回折ピークを測定する。その後、ＸＲＤ解析ソフト（例えば、（株）リガク製、製品名「統合粉末Ｘ線解析ソフトウェアＰＤＸＬ２」）を用いて、α－クリストバライト相の（１０１面）の半値幅を算出する。
　Ｘ線源：ＣｕＫα
　管電圧：４０ｋＶ
　管電流：４０ｍＡ
　スキャン速度：４．０°／ｍｉｎ
　２θスキャン範囲：１０°～５０° In the inorganic powder according to the present embodiment, the full width of half maximum intensity (FWHM) of the (101 plane) X-ray diffraction peak (XRD) of the α-cristobalite phase (hereinafter simply referred to as "half maximum intensity") ) is 0.120° to 0.300°, preferably 0.140° to 0.300°, and more preferably 0.150° to 0.260°. By having a half-value width of 0.120° to 0.300°, the α-β phase transition temperature of the inorganic powder can be dispersed, and it does not show local thermal expansion, and when mixed with resin, the α-β phase transition temperature can be dispersed. The effect of mitigating thermal expansion accompanying β phase transition can be obtained. Thereby, crystalline silica powder with a low coefficient of thermal expansion can be obtained. Note that the half width can be measured under the following conditions.
<Method for measuring X-ray diffraction of inorganic powder>
The X-ray diffraction peak of the inorganic powder is measured under the following conditions using an XRD apparatus (for example, manufactured by Rigaku Co., Ltd., product name "RINT-Ultima IV"). Thereafter, the half-value width of the (101 plane) of the α-cristobalite phase is calculated using XRD analysis software (for example, manufactured by Rigaku Co., Ltd., product name "Integrated Powder X-ray Analysis Software PDXL2").
X-ray source: CuKα
Tube voltage: 40kV
Tube current: 40mA
Scan speed: 4.0°/min
2θ scan range: 10° to 50°
　前記半値幅を満たす無機粉末は、例えば、α－クリストバライト相の（１０１面）の半値幅が広い結晶質シリカ粉末（例えば、前記（１０１面）の半値幅が０．３００°に近いかそれ以上の結晶質シリカ粉末、より好ましくは、前記半値幅が０．２８０°以上０．３８０°以下の結晶質シリカ粉末）と、前記（１０１面）の半値幅が狭い結晶質シリカ粉末（例えば、前記（１０１面）の半値幅が０．１２０°に近いかそれ以下の結晶質シリカ粉末、より好ましくは、前記半値幅が０．１００°以上０．１５０°以下の結晶質シリカ粉末）を、２種類以上混合することにより得られやすくなる。 The inorganic powder that satisfies the above-mentioned half-width is, for example, a crystalline silica powder having a wide half-width of the (101 plane) in the α-cristobalite phase (for example, the half-width of the (101 plane) is close to or larger than 0.300°. crystalline silica powder, more preferably the crystalline silica powder whose half-width is 0.280° or more and 0.380° or less); (101 plane) crystalline silica powder whose half-width is close to 0.120° or less, more preferably crystalline silica powder whose half-width is 0.100° or more and 0.150° or less), It becomes easier to obtain by mixing more than one type.
＜結晶質シリカ粉末＞
　本実施形態に係る無機粉末は、α－β相転移開始温度が異なる少なくとも２種類の結晶質シリカ粉末を含む。結晶質シリカ粉末のα－β相転移開始温度は、例えば、示差走査熱量計を用いて、昇温速度１０℃／分の条件で室温から３００℃まで結晶質シリカ粉末を昇温した際に得られるＤＳＣ曲線における、吸熱ピークの開始温度から特定できる。より具体的には、ＤＳＣ曲線の吸熱ピークの開始温度のベースラインの傾きに沿って引いたラインと、グラフの下側に向かって伸びる吸熱ピークの最初の変曲点に沿って引いたラインとの交点の温度を指す。例えば、図２に示すＤＳＣ曲線の場合、吸熱ピークの開始温度のベースラインの傾きに沿うように引いたラインＬ１と、吸熱ピークの最初の変曲点に沿って引いたラインとの交点（開始点１）の温度を意味する。なお図２は、比較例３の球状クリストバライト粉末（１種類）のＤＳＣ曲線の一例である。また本明細書において、「室温」とは、０～４０℃のことを指す。 <Crystalline silica powder>
The inorganic powder according to this embodiment includes at least two types of crystalline silica powders having different α-β phase transition initiation temperatures. The α-β phase transition initiation temperature of crystalline silica powder can be determined, for example, by heating the crystalline silica powder from room temperature to 300°C at a heating rate of 10°C/min using a differential scanning calorimeter. It can be identified from the starting temperature of the endothermic peak in the DSC curve. More specifically, a line drawn along the slope of the baseline of the starting temperature of the endothermic peak of the DSC curve, and a line drawn along the first inflection point of the endothermic peak extending toward the bottom of the graph. refers to the temperature at the intersection of For example, in the case of the DSC curve shown in Figure 2, the intersection point (start It means the temperature at point 1). Note that FIG. 2 is an example of a DSC curve of the spherical cristobalite powder (one type) of Comparative Example 3. Further, in this specification, "room temperature" refers to 0 to 40°C.
　また本実施形態において、「α－β相転移開始温度が異なる、結晶質シリカ粉末」とは、α－β相転移開始温度が１℃以上異なる（ただし、α－β相転移終了温度の差が５℃以下のものを除く）結晶質シリカ粉末を意味する。「α－β相転移終了温度」とは、前述のＤＳＣ曲線の吸熱ピークの終了温度のベースラインの傾きに沿って引いたラインと、グラフの上側に向かって伸びる吸熱ピークの最後の変曲点（ピークの高温側の変曲点）に沿って引いたラインとの交点の温度を指す。例えば、図２に示すＤＳＣ曲線の場合、吸熱ピークの終了温度のベースラインの傾きに沿って引いたラインＬ２と、吸熱ピークの最後の変曲点に沿って引いたラインとの交点（終了点２）の温度を意味する。なお、本実施形態に係る無機粉末において、α－β相転移開始温度が異なる、結晶質シリカ粉末を２種類以上含むかどうかは、前述の条件で無機粉末を示差走査熱量計で測定した際に、得られるＤＳＣ曲線内に複数の吸熱ピークが観測されること等によって、確認することができる。 In the present embodiment, "crystalline silica powders with different α-β phase transition start temperatures" are defined as "crystalline silica powders with different α-β phase transition start temperatures" (provided that the α-β phase transition start temperatures differ by 1°C or more (however, the difference in α-β phase transition end temperatures is means crystalline silica powder (excluding those whose temperature is below 5°C). "α-β phase transition end temperature" refers to the line drawn along the slope of the baseline of the end temperature of the endothermic peak of the DSC curve mentioned above, and the last inflection point of the endothermic peak extending toward the upper side of the graph. (the inflection point on the high temperature side of the peak). For example, in the case of the DSC curve shown in FIG. 2, the intersection point (end point 2) means the temperature. Note that whether or not the inorganic powder according to the present embodiment contains two or more types of crystalline silica powder with different α-β phase transition start temperatures can be determined by measuring the inorganic powder with a differential scanning calorimeter under the above-mentioned conditions. This can be confirmed by the observation of multiple endothermic peaks within the resulting DSC curve.
　図３は実施例１の無機粉末のＤＳＣ曲線の一例である。図３に示すように、本実施形態に係る無機粉末のＤＳＣ曲線には、複数の吸熱ピークを有する場合がある。 FIG. 3 is an example of a DSC curve of the inorganic powder of Example 1. As shown in FIG. 3, the DSC curve of the inorganic powder according to this embodiment may have multiple endothermic peaks.
　本実施形態に係る無機粉末は、α－β相転移開始温度が異なる結晶質シリカ粉末を２種類以上含む混合粉末である。なお、本実施形態において、無機粉末に含まれる結晶質シリカ粉末のα－β相転移開始温度は、半値幅が０．１２０°～０．３００°となる範囲で調整し得る。一態様において、無機粉末は、α－β相転移開始温度が１７０～２８０℃の範囲内にある結晶質シリカ粉末であって、α－β相転移開始温度が１℃以上異なる（ただし、α－β相転移終了温度の差が５℃以下のものを除く）結晶質シリカ粉末を少なくとも２種類含んでいてもよい。 The inorganic powder according to the present embodiment is a mixed powder containing two or more types of crystalline silica powders having different α-β phase transition start temperatures. In the present embodiment, the α-β phase transition start temperature of the crystalline silica powder contained in the inorganic powder can be adjusted within a range where the half-width is 0.120° to 0.300°. In one embodiment, the inorganic powder is a crystalline silica powder having an α-β phase transition starting temperature within a range of 170 to 280°C, and the α-β phase transition starting temperature differs by 1°C or more (however, α- At least two types of crystalline silica powder (excluding those with a difference in β-phase transition completion temperature of 5° C. or less) may be included.
　無機粉末に含まれる結晶質シリカ粉末の種類の上限は、本発明の効果を有する限り特に限定されない。無機粉末中の結晶質シリカ粉末は３種類であってもよく、４種類であってもよい。なお、製造コストとのバランスをとる観点からは、無機粉末に含まれる、α－β相転移開始温度が異なる結晶質シリカ粉末の種類は、１２種類以下であることが好ましい。 The upper limit of the type of crystalline silica powder contained in the inorganic powder is not particularly limited as long as it has the effects of the present invention. The number of types of crystalline silica powder in the inorganic powder may be three or four types. From the viewpoint of balancing production costs, it is preferable that the inorganic powder contains 12 or less types of crystalline silica powders having different α-β phase transition initiation temperatures.
　本実施形態に係る無機粉末は、従来のクリストバライト粉末よりも低い熱膨張係数を有する。図１は、比較例３の球状クリストバライト粉末（一般的な球状クリストバライト粉末）のＴＭＡ曲線を含むグラフである。図１の球状クリストバライト粉末のＴＭＡ曲線には、２４０～２５０℃付近で急激な立ち上がり、すなわち、熱膨張率の急激な上昇がみられる。このときの熱膨張係数は約５０×１０－５／Ｋである。このように、球状クリストバライト粉末は、加熱した際に、特定の温度範囲でα相からβ相への相転移に伴って熱膨張率が急激に上昇するため非常に扱いづらい。本実施形態に係る無機粉末は、例えば、図４に示すように、２４０～２５０℃でＴＭＡ曲線の急激な立ち上がりが見られない。また、２００～２８０℃の広い温度範囲でも、ＴＭＡ曲線の急激な立ち上がりはなく、比較的リニアなＴＭＡ曲線となる。このようなＴＭＡ曲線を有する無機粉末は、従来のクリストバライト粉末よりも低い熱膨張係数を有するため取り扱いが容易である。また、非晶質シリカ粉末や、石英粉末よりも高熱膨張率であるため、半導体封止材用フィラーとして好適に用いることができる。 The inorganic powder according to this embodiment has a lower coefficient of thermal expansion than conventional cristobalite powder. FIG. 1 is a graph including the TMA curve of the spherical cristobalite powder of Comparative Example 3 (general spherical cristobalite powder). The TMA curve of the spherical cristobalite powder in FIG. 1 shows a sharp rise at around 240 to 250°C, that is, a rapid increase in the coefficient of thermal expansion. The thermal expansion coefficient at this time is approximately 50×10 −5 /K. As described above, when spherical cristobalite powder is heated, it is very difficult to handle because the coefficient of thermal expansion rapidly increases due to the phase transition from the α phase to the β phase in a specific temperature range. In the inorganic powder according to the present embodiment, for example, as shown in FIG. 4, no sharp rise in the TMA curve is observed at 240 to 250°C. Further, even in a wide temperature range of 200 to 280° C., there is no sudden rise in the TMA curve, and the TMA curve is relatively linear. An inorganic powder having such a TMA curve is easier to handle because it has a lower coefficient of thermal expansion than conventional cristobalite powder. Furthermore, since it has a higher coefficient of thermal expansion than amorphous silica powder or quartz powder, it can be suitably used as a filler for semiconductor encapsulant.
　本実施形態において、無機粉末に含まれる少なくとも２種類の結晶質シリカ粉末の、結晶相及び非晶質相の合計量（１００質量％）に対するα－クリストバライト相の割合は、いずれも３０質量％以上であり、４０質量％以上であってもよく、５０質量％以上であってもよい。無機粉末に含まれる結晶質シリカ粉末の結晶相及び非晶質相の合計量（１００質量％）に対するα－クリストバライト相の割合が、いずれも３０質量％以上であることにより、熱膨張率の高い無機粉末が得られる。なお、本明細書において、「結晶質シリカ粉末」とは、結晶相を３０質量％以上含み、α－クリストバライト相を３０質量％以上含むシリカ粉末（すなわち、結晶化率が３０質量％以上、クリストバライト化率が３０質量％以上のシリカ粉末）のことを指す。結晶質シリカ粉末の結晶相、非晶質相の割合、及びα－クリストバライト相の割合は、Ｘ線回折により測定することができる。具体的には以下の方法で測定できる。なお、以下の方法では、α－クリストバライト相、石英相及びトリジマイト相の計算方法を示しているが、それ以外のシリカの結晶相も同様の方法で計算できる。 In the present embodiment, the ratio of the α-cristobalite phase to the total amount (100 mass%) of the crystalline phase and the amorphous phase of at least two types of crystalline silica powders contained in the inorganic powder is 30% by mass or more. The content may be 40% by mass or more, or may be 50% by mass or more. The ratio of the α-cristobalite phase to the total amount (100 mass%) of the crystalline phase and the amorphous phase of the crystalline silica powder contained in the inorganic powder is 30% by mass or more, so that the coefficient of thermal expansion is high. An inorganic powder is obtained. In this specification, "crystalline silica powder" refers to silica powder containing 30% by mass or more of a crystalline phase and 30% by mass or more of an α-cristobalite phase (i.e., crystallization rate of 30% by mass or more, cristobalite refers to silica powder with a conversion rate of 30% by mass or more). The crystalline phase, amorphous phase proportion, and α-cristobalite phase proportion of the crystalline silica powder can be measured by X-ray diffraction. Specifically, it can be measured by the following method. Note that although the following method shows calculation methods for α-cristobalite phase, quartz phase, and tridymite phase, other silica crystal phases can also be calculated using the same method.
＜結晶質シリカ粉末の結晶相の割合及び結晶相の組成分析＞
　まず結晶質シリカ粉末の結晶相の組成をＸ線回折測定（ＸＲＤ測定）より確認する。具体的には、ＸＲＤ装置（例えば、（株）リガク製、製品名「ＲＩＮＴ－ＵｌｔｉｍａＩＶ」）を用いて、以下の条件で結晶質シリカ粉末のＸ線回折ピークを測定する。
　Ｘ線源：ＣｕＫα
　管電圧：４０ｋＶ
　管電流：４０ｍＡ
　スキャン速度：４．０°／ｍｉｎ
　２θスキャン範囲：１０°～５０°
　その後、結晶質シリカ粉末で検出された各結晶相のピークの積分強度（Ｉｑ、Ｉｃ、Ｉｔ）と各結晶相の標準試料のピークの積分強度（Ｓｑ、Ｓｃ、Ｓｔ）を用いて、下記式（１）～（４）より各結晶相の割合及び結晶相の割合を算出する。
　（石英相の割合）＝ΣＩｑ／ΣＳｑ×１００　・・・（１）
　（α－クリストバライト相の割合）＝ΣＩｃ／ΣＳｃ×１００　・・・（２）
　（トリジマイト相の割合）＝ΣＩｔ／ΣＳｔ×１００　・・・（３）
　（結晶相の割合）＝（石英相の割合）＋（α－クリストバライト相の割合）＋（トリジマイト相の割合）　・・・（４）
　なお、式（１）～（４）中、Σはある特定の結晶相の複数のピークの積分強度の和を示す。また、ｑは石英相、ｃはα－クリストバライト相、ｔはトリジマイト相を示す。 <Ratio of crystalline phase of crystalline silica powder and composition analysis of crystalline phase>
First, the composition of the crystal phase of the crystalline silica powder is confirmed by X-ray diffraction measurement (XRD measurement). Specifically, the X-ray diffraction peak of the crystalline silica powder is measured under the following conditions using an XRD apparatus (for example, manufactured by Rigaku Co., Ltd., product name "RINT-Ultima IV").
X-ray source: CuKα
Tube voltage: 40kV
Tube current: 40mA
Scan speed: 4.0°/min
2θ scan range: 10° to 50°
Then, using the integrated intensity of the peak of each crystalline phase detected in the crystalline silica powder (Iq, Ic, It) and the integrated intensity of the peak of the standard sample of each crystalline phase (Sq, Sc, St), the following formula is calculated. The ratio of each crystal phase and the ratio of crystal phases are calculated from (1) to (4).
(Percentage of quartz phase) = ΣIq / ΣSq × 100 ... (1)
(α-cristobalite phase ratio) = ΣIc/ΣSc×100 (2)
(Ratio of tridymite phase)=ΣIt/ΣSt×100 (3)
(Ratio of crystal phase) = (Ratio of quartz phase) + (Ratio of α-cristobalite phase) + (Ratio of tridymite phase) ... (4)
Note that in formulas (1) to (4), Σ represents the sum of integrated intensities of a plurality of peaks of a particular crystal phase. Furthermore, q represents a quartz phase, c represents an α-cristobalite phase, and t represents a tridymite phase.
　なお、ＸＲＤ測定により得られたピーク強度比より各結晶相の割合を算出してもよい。算出の際は各ピークをピーク分離する。ピークの積分強度の算出は、例えば、統合粉末Ｘ線解析ソフトウェア（例えば、（株）リガク製、製品名「ＰＤＸＬ２」）を用いることができる。簡易的には、各結晶相の最大ピークの積分強度、例えば、石英相は（１０１面、ｄ＝３．３４２）、α－クリストバライト相は（１０１面、ｄ＝４．０５）、トリジマイト相は（２１１面、ｄ＝４．１０７）を用いて、１本のピークの積分強度より算出しても良い（下記式（５）～（８））。ここで、添字の（１０１）、（２２１）は各結晶相の回折ピークの面指数を表す。
　（石英相の割合）＝Ｉｑ（１０１）／Ｓｑ（１０１）×１００　・・・（５）
　（α－クリストバライト相の割合）＝Ｉｃ（１０１）／Ｓｃ（１０１）×１００　・・・（６）
　（トリジマイト相の割合）＝Ｉｔ（２２１）／Ｓｔ（２２１）×１００　・・・（７）
　（結晶相の割合）＝（石英相の割合）＋（α－クリストバライト相の割合）＋（トリジマイト相の割合）　・・・（８） Note that the proportion of each crystal phase may be calculated from the peak intensity ratio obtained by XRD measurement. When calculating, each peak is separated. The integrated intensity of the peak can be calculated using, for example, integrated powder X-ray analysis software (for example, manufactured by Rigaku Co., Ltd., product name "PDXL2"). In simple terms, the integrated intensity of the maximum peak of each crystal phase, for example, the quartz phase is (101 plane, d = 3.342), the α-cristobalite phase is (101 plane, d = 4.05), and the tridymite phase is (211 plane, d=4.107) may be used to calculate from the integrated intensity of one peak (formulas (5) to (8) below). Here, subscripts (101) and (221) represent plane indices of the diffraction peaks of each crystal phase.
(Percentage of quartz phase)=Iq(101)/Sq(101)×100...(5)
(Proportion of α-cristobalite phase) = Ic (101) / Sc (101) × 100 (6)
(Ratio of tridymite phase)=It(221)/St(221)×100...(7)
(Ratio of crystal phase) = (Ratio of quartz phase) + (Ratio of α-cristobalite phase) + (Ratio of tridymite phase) ... (8)
　一態様において、結晶質シリカ粉末の結晶化率は３０質量％以上であってもよく、５０質量％以上であってもよく、７０質量％以上であってもよい。 In one embodiment, the crystallinity of the crystalline silica powder may be 30% by mass or more, 50% by mass or more, or 70% by mass or more.
　結晶質シリカ粉末はα－クリストバライト相以外の結晶相及び非晶質相（アモルファス相）（以下、「その他の相」と記載することもある）を含むことができる。すなわち、結晶質シリカ粉末は、α－クリストバライト相と、石英相、トリジマイト相、及び非晶質相から選択される少なくとも１つと、を含んでいてもよい。結晶質シリカ粉末が、石英相、トリジマイト相、及び非晶質相から選択される少なくとも１つを含む場合、低温域（２００℃付近）で熱膨張挙動が生じやすく、ＴＭＡ曲線がよりリニアになりやすい。一つの態様において、α－クリストバライト相以外のその他の相の割合は、全結晶相及び非晶質相の合計量（１００質量％）に対して、７０質量％以下が好ましく、５０質量％以下がより好ましい。より高熱膨張率の無機粉末が得られやすい観点からは、α－クリストバライト相のみを結晶相として有する結晶質シリカ粉末を含んでいてもよい。 The crystalline silica powder can contain a crystalline phase and an amorphous phase (hereinafter sometimes referred to as "other phases") other than the α-cristobalite phase. That is, the crystalline silica powder may include an α-cristobalite phase and at least one selected from a quartz phase, a tridymite phase, and an amorphous phase. When the crystalline silica powder contains at least one selected from a quartz phase, a tridymite phase, and an amorphous phase, thermal expansion behavior tends to occur in a low temperature range (around 200 ° C.), and the TMA curve becomes more linear. Cheap. In one embodiment, the proportion of other phases other than the α-cristobalite phase is preferably 70% by mass or less, and 50% by mass or less based on the total amount (100% by mass) of all crystalline phases and amorphous phases. More preferred. From the viewpoint of easily obtaining an inorganic powder with a higher coefficient of thermal expansion, it may contain crystalline silica powder having only an α-cristobalite phase as a crystalline phase.
　本実施形態において、無機粉末に含まれる、α－β相転移開始温度が最も低い結晶質シリカ粉末（Ａ）（以下、「シリカ粉末（Ａ）」と記載する）のα－β相転移開始温度（ＴＡ）と、α－β相転移開始温度が最も高い結晶質シリカ粉末（Ｂ）（以下、「シリカ粉末（Ｂ）」と記載する）のα－β相転移開始温度（ＴＢ）との差（ＴＢ－ＴＡ）は、９０℃以下であることが好ましく、８０℃以下であることがより好ましく、７５℃以下であることがさらに好ましい。（ＴＢ－ＴＡ）が９０℃以下となるように、２種類以上の結晶質シリカ粉末を混合することにより、急激な熱膨張率の立ち上がりのないＴＭＡ曲線が得られやすくなる。その結果、熱膨張係数のより低い無機粉末が得られやすい。一態様において、（ＴＢ－ＴＡ）は１～９０℃であってもよく、５～９０℃であってもよく、１０～９０℃であってもよい。 In this embodiment, the α-β phase transition start temperature of crystalline silica powder (A) (hereinafter referred to as "silica powder (A)"), which is included in the inorganic powder and has the lowest α-β phase transition start temperature. (TA) and the α-β phase transition initiation temperature (TB) of crystalline silica powder (B) (hereinafter referred to as "silica powder (B)") with the highest α-β phase transition initiation temperature (TB-TA) is preferably at most 90°C, more preferably at most 80°C, even more preferably at most 75°C. By mixing two or more types of crystalline silica powder so that (TB-TA) is 90° C. or less, it becomes easier to obtain a TMA curve without a sudden rise in the coefficient of thermal expansion. As a result, it is easy to obtain an inorganic powder with a lower coefficient of thermal expansion. In one embodiment, (TB-TA) may be between 1 and 90°C, may be between 5 and 90°C, or may be between 10 and 90°C.
　シリカ粉末（Ａ）のα－β相転移開始温度（ＴＡ）は、１７０～２５０℃であることが好ましく、１８０～２４０℃であることがより好ましく、１８０～２３５℃であることがさらに好ましい。また、シリカ粉末（Ｂ）のα－β相転移開始温度（ＴＢ）は、２００～２８０℃であることが好ましく、２３０～２８０℃がより好ましく、２３５～２７５℃であることがさらに好ましく、２４０～２７０℃であることが特に好ましい。（ＴＡ）及び（ＴＢ）が前記範囲内であれば、（ＴＢ－ＴＡ）を９０℃以下に調整しやすくなる。またこのようなシリカ粉末（Ａ）及び（Ｂ）を含むことにより、比較的リニアなＴＭＡ曲線が得られやすくなり、熱膨張係数のより低い無機粉末となりやすい。 The α-β phase transition initiation temperature (TA) of the silica powder (A) is preferably 170 to 250°C, more preferably 180 to 240°C, even more preferably 180 to 235°C. Further, the α-β phase transition initiation temperature (TB) of the silica powder (B) is preferably 200 to 280°C, more preferably 230 to 280°C, even more preferably 235 to 275°C, and even more preferably 240 to 280°C. It is particularly preferred that the temperature is between 270°C and 270°C. If (TA) and (TB) are within the above range, (TB-TA) can be easily adjusted to 90° C. or less. Moreover, by including such silica powders (A) and (B), a relatively linear TMA curve can be easily obtained, and an inorganic powder with a lower coefficient of thermal expansion can be easily obtained.
　本実施形態に係る無機粉末は、上記の通り、α－β相転移開始温度の異なる結晶質シリカ粉末を２種類以上含んでいる。α－クリストバライト相を一定量以上含む結晶質シリカ粉末のＴＭＡ曲線は、通常、図１の球状クリストバライト粉末のＴＭＡ曲線に示すように、α相からβ相への相転移に伴って熱膨張率の急激な上昇が発生する。その結果、球状クリストバライト粉末の熱膨張係数が非常に大きくなる。本実施形態に係る無機粉末では、比較的リニアなＴＭＡ曲線が得られる。本発明者は前記半値幅の異なる、α－クリストバライト相を一定量含む結晶質シリカ粉末は、それぞれ異なる熱特性を示すことを見出し、それを複数種類組み合わせて適切な半値幅に調整することにより、熱膨張率の急激な上昇を抑え、熱膨張係数の低い無機粉末が得られることを見出した。 As described above, the inorganic powder according to the present embodiment contains two or more types of crystalline silica powders having different α-β phase transition start temperatures. As shown in the TMA curve of spherical cristobalite powder in Figure 1, the TMA curve of crystalline silica powder containing a certain amount or more of α-cristobalite phase usually shows a change in thermal expansion coefficient due to phase transition from α phase to β phase. A sudden rise occurs. As a result, the coefficient of thermal expansion of the spherical cristobalite powder becomes very large. The inorganic powder according to this embodiment provides a relatively linear TMA curve. The present inventor found that the crystalline silica powders containing a certain amount of α-cristobalite phase, which have different half-widths, each exhibit different thermal properties, and by combining multiple types and adjusting the half-width to an appropriate half-width, It has been found that an inorganic powder with a low coefficient of thermal expansion can be obtained by suppressing a rapid increase in the coefficient of thermal expansion.
　特許文献４等に記載の従来の技術は、結晶化率が９０質量％以上であり、かつα－クリストバライト相の割合が９５質量％以上の、高結晶化率を有するクリストバライト粉末に関するものである。このような高結晶化クリストバライト粉末は、比較的狭い半値幅を有することが知られている。一方で、高結晶化クリストバライト粉末の熱膨張挙動の制御については何ら検討されていない。クリストバライト粉末の熱膨張挙動は、製造時の添加剤の種類、焼成時間、焼成温度、及び粒子径等の因子と複雑に関係することが多いため、これらの因子と半値幅及び結晶化率との相関を導き出すことは非常に困難である。本発明では、結晶化率が比較的低いシリカ粉末の半値幅が比較的広いことに着目し、前述の複数の因子を検討することで、クリストバライト粉末の熱特性を制御する方法を見出した。本発明によれば、異なる熱特性を示す複数の結晶質シリカ粉末を組み合わせることで、従来の技術では困難であった、クリストバライトのα－β相転移に伴う熱膨張特性を制御することができる。 The conventional technology described in Patent Document 4 and the like relates to a cristobalite powder having a high crystallinity, in which the crystallinity is 90% by mass or more and the proportion of the α-cristobalite phase is 95% by mass or more. Such highly crystallized cristobalite powder is known to have a relatively narrow half-width. On the other hand, no study has been made on controlling the thermal expansion behavior of highly crystallized cristobalite powder. The thermal expansion behavior of cristobalite powder is often complicatedly related to factors such as the type of additive used during production, firing time, firing temperature, and particle size. Deriving correlations is very difficult. In the present invention, we have focused on the relatively wide half-width of silica powder with a relatively low crystallinity, and have found a method for controlling the thermal properties of cristobalite powder by examining the aforementioned multiple factors. According to the present invention, by combining a plurality of crystalline silica powders exhibiting different thermal properties, it is possible to control the thermal expansion characteristics associated with the α-β phase transition of cristobalite, which has been difficult with conventional techniques.
　本実施形態に係る無機粉末に含まれる結晶質シリカ粉末を構成する粒子の形状は、いずれも球状であることが好ましい。粒子形状が球状の結晶質シリカ粉末を含むことにより、無機粉末の樹脂への充填性及び分散性がより向上する。なお、「粒子形状が球状である」とは、顕微鏡などで結晶質シリカ粉末に含まれる粒子を観察した際に、その投影図（立体図及び平面図含む）が円形に近い形状を有することを意味する。
　一態様において、結晶質シリカ粉末の平均円形度は、０．８０以上が好ましく、０．８５以上がより好ましく、０．９０以上がさらに好ましい。結晶質シリカ粉末の平均円形度が０．８０以上であれば、本実施形態に係る無機粉末の平均円形度を好ましい範囲に調整しやすくなる。また、本実施形態に係る無機粉末の樹脂への分散性が向上しやすくなる。また、樹脂の粘度が増加して流動性が低下することを防ぎやすく、加工性や充填性が悪化しにくい。結晶質シリカ粉末の「平均円形度」は、以下の方法で算出することができる。
＜平均円形度＞
　結晶質シリカ粉末をカーボンテープで固定した後、オスミウムコーティングを行う。その後、走査型電子顕微鏡（例えば、日本電子（株）製、製品名：ＪＳＭ－７００１Ｆ　ＳＨＬ）を用いて、倍率２００～５０，０００倍で粒子を撮影し、画像解析装置（例えば、日本ローパー（株）製、製品名：Ｉｍａｇｅ－Ｐｒｏ　Ｐｒｅｍｉｅｒ　Ｖｅｒ．９．３）を用いて、粒子の投影面積（Ｓ）と投影周囲長（Ｌ）を算出してから、下記の式（９）より円形度を算出する。任意の２００個の粒子について円形度を算出してその平均値を、結晶質シリカ粉末の平均円形度とする。
　円形度＝４πＳ／Ｌ２　・・・（９） It is preferable that all the particles constituting the crystalline silica powder contained in the inorganic powder according to this embodiment have a spherical shape. By including the crystalline silica powder having a spherical particle shape, the filling properties and dispersibility of the inorganic powder into the resin are further improved. In addition, "the particle shape is spherical" means that when the particles contained in the crystalline silica powder are observed under a microscope, the projected view (including a three-dimensional view and a plan view) has a shape close to a circle. means.
In one embodiment, the average circularity of the crystalline silica powder is preferably 0.80 or more, more preferably 0.85 or more, and even more preferably 0.90 or more. When the average circularity of the crystalline silica powder is 0.80 or more, it becomes easy to adjust the average circularity of the inorganic powder according to this embodiment to a preferable range. Further, the dispersibility of the inorganic powder according to the present embodiment into the resin can be easily improved. In addition, it is easy to prevent the resin from increasing in viscosity and decreasing its fluidity, and its processability and filling properties are less likely to deteriorate. The "average circularity" of crystalline silica powder can be calculated by the following method.
<Average circularity>
After fixing the crystalline silica powder with carbon tape, osmium coating is performed. Thereafter, the particles are photographed using a scanning electron microscope (for example, JEOL Ltd., product name: JSM-7001F SHL) at a magnification of 200 to 50,000 times, and an image analysis device (for example, Nippon Roper (Japan Roper)) is used to photograph the particles. Co., Ltd., product name: Image-Pro Premier Ver. 9.3), calculate the projected area (S) and projected perimeter (L) of the particle, and then calculate the circularity using the following formula (9) Calculate. The circularity is calculated for any 200 particles, and the average value is defined as the average circularity of the crystalline silica powder.
Circularity = 4πS/L 2 ...(9)
　本実施形態に係る結晶質シリカ粉末の平均粒子径（Ｄ５０）は、いずれも、１～１００μｍが好ましく、４～１００μｍがより好ましく、５～８０μｍがさらに好ましい。結晶質シリカ粉末の平均粒子径（Ｄ５０）が前記範囲内であれば、得られる無機粉末の樹脂への充填性がより良好となりやすい。なお、結晶質シリカ粉末の平均粒子径は、レーザー回折式粒度分布測定装置を用いて測定される、体積基準の累積粒度分布において、累積値が５０％に相当する粒子径（Ｄ５０）のことを指す。累積粒度分布は、横軸を粒子径（μｍ）、縦軸を累積値（％）とする分布曲線で表される。 The average particle diameter (D50) of the crystalline silica powder according to the present embodiment is preferably 1 to 100 μm, more preferably 4 to 100 μm, and even more preferably 5 to 80 μm. If the average particle diameter (D50) of the crystalline silica powder is within the above range, the filling properties of the obtained inorganic powder into the resin tend to be better. The average particle diameter of crystalline silica powder is the particle diameter (D50) at which the cumulative value corresponds to 50% in the volume-based cumulative particle size distribution measured using a laser diffraction particle size distribution analyzer. Point. The cumulative particle size distribution is represented by a distribution curve with the horizontal axis representing the particle diameter (μm) and the vertical axis representing the cumulative value (%).
　本実施形態に係る無機粉末に含まれる結晶質シリカ粉末の比表面積は、０．１～１０ｍ２／ｇであることが好ましく、０．３～５ｍ２／ｇであることがより好ましい。結晶質シリカ粉末の比表面積が前記範囲内であれば、流動性と熱伝導性が良好となりやすい。なお、結晶質シリカ粉末の比表面積は、ＢＥＴ法により測定することができる。
＜比表面積の測定方法＞
　測定用セルに結晶質シリカ粉末を１ｇ充填し、全自動比表面積径測定装置（例えばＭｏｕｎｔｅｃｈ社製、製品名：Ｍａｃｓｏｒｂ　ＨＭ　ｍｏｄｅｌ－１２０１（ＢＥＴー点法））を用いて、結晶質シリカ粉末の比表面積を測定する。なお、測定前の脱気条件は、２００℃、１０分間とすることができる。 The specific surface area of the crystalline silica powder contained in the inorganic powder according to this embodiment is preferably 0.1 to 10 m 2 /g, more preferably 0.3 to 5 m 2 /g. When the specific surface area of the crystalline silica powder is within the above range, fluidity and thermal conductivity tend to be good. Note that the specific surface area of the crystalline silica powder can be measured by the BET method.
<Method for measuring specific surface area>
Fill a measuring cell with 1 g of crystalline silica powder, and use a fully automatic specific surface area diameter measuring device (for example, manufactured by Mountech, product name: Macsorb HM model-1201 (BET-point method)) to measure the amount of crystalline silica powder. Measure the specific surface area. Note that the degassing conditions before measurement can be 200° C. and 10 minutes.
　本実施形態に係る無機粉末に含まれる結晶質シリカ粉末の平均粒子密度は、２．２０～２．５０ｇ／ｃｍ３が好ましく、２．２８～２．４０ｇ／ｃｍ３がより好ましい。結晶質シリカ粉末の平均粒子密度が前記範囲内であれば、球状非晶質シリカと比べて熱伝導率が高くなりやすい。なお、結晶質シリカ粉末の平均粒子密度は以下の方法で測定することができる。
＜平均粒子密度の測定方法＞
　結晶質シリカ粉末２．０ｇを測定用試料セルに入れ、乾式密度計（例えば（株）島津製作所製、製品名：アキュピックＩＩ　１３４０）を用い、気体（ヘリウム）置換法により平均粒子密度を測定する。 The average particle density of the crystalline silica powder contained in the inorganic powder according to the present embodiment is preferably 2.20 to 2.50 g/cm 3 , more preferably 2.28 to 2.40 g/cm 3 . If the average particle density of the crystalline silica powder is within the above range, the thermal conductivity tends to be higher than that of spherical amorphous silica. Note that the average particle density of crystalline silica powder can be measured by the following method.
<Method for measuring average particle density>
2.0 g of crystalline silica powder is placed in a measurement sample cell, and the average particle density is measured by a gas (helium) displacement method using a dry density meter (for example, manufactured by Shimadzu Corporation, product name: Accupic II 1340). .
　本実施形態に係る無機粉末に含まれる結晶質シリカ粉末は、表面処理剤で表面処理されていてもよい。表面処理剤で表面処理されることにより、本実施形態に係る無機粉末の樹脂への充填性がより良好となりやすい。表面処理剤としては、例えば、シランカップリング剤、アルミネートカップリング剤等が挙げられる。これらは１種単独で用いられてもよく、２種以上を併用してもよい。なお、無機粉末に含まれる結晶質シリカ粉末の表面処理の有無は、例えば、ＩＲ、ＴＧ－ＤＴＡ、質量分析法等で結晶質シリカ粉末を分析することにより確認できる。 The crystalline silica powder contained in the inorganic powder according to this embodiment may be surface-treated with a surface-treating agent. By surface-treating with a surface-treating agent, the filling properties of the inorganic powder according to the present embodiment into the resin tend to be better. Examples of the surface treatment agent include silane coupling agents, aluminate coupling agents, and the like. These may be used alone or in combination of two or more. Note that the presence or absence of surface treatment of the crystalline silica powder contained in the inorganic powder can be confirmed by analyzing the crystalline silica powder using, for example, IR, TG-DTA, mass spectrometry, or the like.
　本実施形態に係る無機粉末の平均円形度は０．８０以上が好ましく、０．８５以上がより好ましく、０．９０以上がさらに好ましい。無機粉末の平均円形度が０．８０以上であれば、樹脂への充填性及び分散性が向上しやすい。なお、無機粉末の平均円形度は前述の結晶質シリカ粉末と同じ方法で測定できる。 The average circularity of the inorganic powder according to this embodiment is preferably 0.80 or more, more preferably 0.85 or more, and even more preferably 0.90 or more. If the average circularity of the inorganic powder is 0.80 or more, the filling properties and dispersibility into the resin are likely to be improved. Note that the average circularity of the inorganic powder can be measured by the same method as the above-mentioned crystalline silica powder.
　本実施形態に係る無機粉末の平均粒子径（Ｄ５０）は、調整の容易さ及び流動性の観点から、１００μｍ以下が好ましい。一態様において、前記平均粒子径（Ｄ５０）は１～１００μｍがより好ましく、２～９０μｍがさらに好ましく、３～８０μｍが特に好ましい。無機粉末の平均粒子径（Ｄ５０）は、前述の結晶質シリカ粉末と同じ方法で測定できる。 The average particle diameter (D50) of the inorganic powder according to this embodiment is preferably 100 μm or less from the viewpoint of ease of adjustment and fluidity. In one embodiment, the average particle diameter (D50) is more preferably 1 to 100 μm, even more preferably 2 to 90 μm, and particularly preferably 3 to 80 μm. The average particle diameter (D50) of the inorganic powder can be measured by the same method as for the crystalline silica powder described above.
　本実施形態に係る無機粉末のＴＭＡ曲線から算出される、熱膨張係数の最大値（ＣＴＥｍａｘ）は、４０×１０－５／Ｋ以下が好ましく、３５×１０－５／Ｋ以下がより好ましく、３１×１０－５／Ｋ以下がさらに好ましい。なお、ＣＴＥｍａｘは、以下の条件で測定算出することができる。
＜ＣＴＥｍａｘの算出方法＞
　エポキシ樹脂（エポキシ当量：１８４～１９４。例えば、三菱ケミカル（株）製、製品名「ＪＥＲ８２８」）２０．０質量部、４、４’－ジアミノジフェニルメタン５．０質量部を９５℃で溶融させながら混合し、無機粉末を体積％換算で４０％になるように加え、遊星式撹拌機（回転数２０００ｒｐｍ）にて混合する。予め加熱しておいたシリコーン製の型枠（２ｃｍ角×５ｍｍ厚）に上記混合物を流し込み、８０℃で２０分間静置し、真空加熱プレス機（例えば、（株）井元製作所製、製品名「ＩＭＣ－１６７４－Ａ型」）で、８０℃、３．０ＭＰａで１時間、１５０℃、５．０ＭＰａで１時間、２００℃、７ＭＰａで０．５時間の順でプレス加熱して硬化させる。硬化後、４ｍｍ×４ｍｍ×１５ｍｍ（高さ）に加工して測定用サンプルを作成し、ＴＭＡ（例えば、ブルカー社製、製品名「ＴＭＡ４０００ＳＡ」）にて熱膨張率を測定する。昇温条件は、５℃／ｍｉｎ、測定温度は－１０℃～３００℃とし、窒素雰囲気で２ｃｙｃｌｅ測定し、得られたＴＭＡ測定チャートの２ｃｙｃｌｅ目から、１７０～２７０℃の温度範囲において、１０℃毎に熱膨張係数を算出し、その最大値をＣＴＥｍａｘとする。また、同様の方法で算出した熱膨張係数のうち、最小値をＣＴＥｍｉｎとすることができる。
　なお、ＣＴＥｍａｘ、ＣＴＥｍｉｎはＴＭＡ曲線の１７０～２７０℃の温度範囲において、１０℃毎に熱膨張係数を算出した際に最も傾きが大きい位置及び最も傾きが小さい位置から算出されることが望ましい。もし、１０℃毎に熱膨張係数を算出する方法では求めることが難しい場合（例えば、クリストバライトのα－β相転移の途中にまたがって算出してしまう場合等）は、α－β相転移による熱膨張率の変動がすべて含まれる範囲に変更して（例えば、１０℃毎ではなく、５℃毎、７℃毎や、１５℃毎等に変更して）熱膨張係数を算出してもよく、もしくは温度範囲を前後にずらして測定して、１０℃毎に熱膨張係数を算出しても構わない。温度範囲を前後にずらす場合は、±５～２０℃の範囲で調整できる。 The maximum value of the coefficient of thermal expansion (CTE max ) calculated from the TMA curve of the inorganic powder according to the present embodiment is preferably 40×10 −5 /K or less, more preferably 35×10 −5 /K or less, More preferably, it is 31×10 −5 /K or less. Note that CTE max can be measured and calculated under the following conditions.
<How to calculate CTE max >
While melting 20.0 parts by mass of an epoxy resin (epoxy equivalent: 184 to 194; for example, manufactured by Mitsubishi Chemical Corporation, product name "JER828") and 5.0 parts by mass of 4,4'-diaminodiphenylmethane at 95°C, Mix, add inorganic powder to give a volume percentage of 40%, and mix using a planetary stirrer (rotation speed: 2000 rpm). Pour the above mixture into a silicone mold (2 cm square x 5 mm thick) that has been heated in advance, leave it at 80°C for 20 minutes, and use a vacuum heat press (for example, manufactured by Imoto Seisakusho Co., Ltd., product name: IMC-1674-A type) was press-heated for 1 hour at 80° C. and 3.0 MPa, 1 hour at 150° C. and 5.0 MPa, and 0.5 hour at 200° C. and 7 MPa for curing. After curing, a sample for measurement is prepared by processing it into a size of 4 mm x 4 mm x 15 mm (height), and the coefficient of thermal expansion is measured using TMA (for example, manufactured by Bruker, product name "TMA4000SA"). The temperature increase condition was 5°C/min, the measurement temperature was -10°C to 300°C, and the measurement was carried out for 2 cycles in a nitrogen atmosphere. From the 2nd cycle of the obtained TMA measurement chart, the temperature was increased by 10°C in the temperature range of 170 to 270°C. The coefficient of thermal expansion is calculated for each time, and its maximum value is defined as CTE max . Further, among the coefficients of thermal expansion calculated using a similar method, the minimum value can be set as CTE min .
In addition, CTE max and CTE min are preferably calculated from the position where the slope is the largest and the position where the slope is the smallest when the thermal expansion coefficient is calculated every 10 degrees Celsius in the temperature range of 170 to 270 degrees Celsius of the TMA curve. . If it is difficult to calculate the coefficient of thermal expansion at every 10°C (for example, when calculating it in the middle of the α-β phase transition of cristobalite), the thermal expansion coefficient due to the α-β phase transition may be The coefficient of thermal expansion may be calculated by changing the range to include all the fluctuations in the expansion coefficient (for example, changing it not every 10 degrees Celsius, but every 5 degrees Celsius, every 7 degrees Celsius, every 15 degrees Celsius, etc.), Alternatively, the thermal expansion coefficient may be calculated for each 10° C. by shifting the temperature range back and forth. When shifting the temperature range forward or backward, it can be adjusted within the range of ±5 to 20°C.
　一態様において、前述の方法で算出した、無機粉末のＣＴＥｍａｘ及びＣＴＥｍｉｎの差（ＣＴＥｍａｘ－ＣＴＥｍｉｎ）は、５．０×１０－５～２０×１０－５／Ｋであってもよく、７．０×１０－５～２０×１０－５／Ｋであってもよい。 In one embodiment, the difference between CTE max and CTE min of the inorganic powder (CTE max - CTE min ) calculated by the above method may be 5.0×10 −5 to 20×10 −5 /K. , 7.0×10 −5 to 20×10 −5 /K.
　一態様において、無機粉末の平均結晶化率（無機粉末に含まれる結晶質シリカ粉末の結晶化率の平均値）は、６０～９０質量％であってもよく、６５～９０質量％であってもよい。また、無機粉末のα－クリストバライト相の割合の平均値（無機粉末に含まれる結晶質シリカ粉末のα－クリストバライト相の平均値）は、６０～９０質量％であってもよく、６１～８８質量％であってもよい。 In one aspect, the average crystallization rate of the inorganic powder (the average value of the crystallization rate of the crystalline silica powder contained in the inorganic powder) may be 60 to 90% by mass, and may be 65 to 90% by mass. Good too. Further, the average value of the ratio of the α-cristobalite phase in the inorganic powder (the average value of the α-cristobalite phase in the crystalline silica powder contained in the inorganic powder) may be 60 to 90% by mass, or 61 to 88% by mass. It may be %.
　本実施形態に係る無機粉末は、前述の結晶質シリカ粉末以外の成分（その他の成分）を含んでいてもよい。一態様において、本実施形態に係る無機粉末は、アルカリ金属、アルカリ土類金属、第一遷移元素、アルミニウム、マグネシウム、イットリウム、及びランタンから選択される少なくとも１つの金属成分を、合計（原子換算）で１００ｐｐｍ以上含んでいてもよい。無機粉末に含まれる前記金属成分は、結晶質シリカ粉末の製造時に添加されたものであってもよい。結晶質シリカ粉末が前述のその他の成分を含む場合、焼成温度をコントロールすることで、所望のα－クリストバライト相比率を有する結晶質シリカ粉末が得られやすくなる。その他の成分は、アルミニウム、亜鉛、チタン、鉄、マンガン、カルシウム、ストロンチウム、バリウム、及びチタンから選択される少なくとも２種類であることが好ましく、アルミニウム、チタン、ストロンチウム及びカルシウムから選択される少なくとも１つを含むことが特に好ましい。また、その他の成分の合計量は、１００～３０，０００ｐｐｍであることがより好ましく、５００～１０，０００ｐｐｍであることがさらに好ましい。無機粉末中のその他成分の量は、仕込み原料で概算でき、また、ＩＣＰ発光分光分析など、元素分析を行うことでより正確に算出できる。 The inorganic powder according to the present embodiment may contain components other than the above-mentioned crystalline silica powder (other components). In one aspect, the inorganic powder according to the present embodiment contains at least one metal component selected from alkali metals, alkaline earth metals, first transition elements, aluminum, magnesium, yttrium, and lanthanum in total (in terms of atoms). It may contain 100 ppm or more. The metal component contained in the inorganic powder may be added at the time of manufacturing the crystalline silica powder. When the crystalline silica powder contains the other components mentioned above, controlling the firing temperature makes it easier to obtain the crystalline silica powder having the desired α-cristobalite phase ratio. The other components are preferably at least two selected from aluminum, zinc, titanium, iron, manganese, calcium, strontium, barium, and titanium, and at least one selected from aluminum, titanium, strontium, and calcium. It is particularly preferable to include. Further, the total amount of other components is more preferably 100 to 30,000 ppm, and even more preferably 500 to 10,000 ppm. The amount of other components in the inorganic powder can be estimated based on the raw materials, and can be calculated more accurately by elemental analysis such as ICP emission spectrometry.
［無機粉末の製造方法］
　次に、本実施形態に係る無機粉末の製造方法の一実施形態について説明する。
　本実施形態に係る無機粉末の製造方法は、α－β相転移開始温度が異なる少なくとも２種類の結晶質シリカ粉末を混合すること（工程（ｉ））を含む。本実施形態に係る製造方法において、工程（ｉ）で混合される少なくとも２種類の結晶質シリカ粉末は、いずれも、結晶相及び非晶質相の合計量（１００質量％）に対するα－クリストバライト相の割合が３０質量％以上である。また、本実施形態に係る無機粉末の製造方法は、α－β相転移開始温度が異なる少なくとも２種類の結晶質シリカ粉末を準備すること（工程（ｉ’））を含んでいてもよい。以下、工程（ｉ’）及び工程（ｉ）を含む製造方法の詳細について説明する。 [Method for producing inorganic powder]
Next, an embodiment of the method for producing inorganic powder according to the present embodiment will be described.
The method for producing inorganic powder according to the present embodiment includes mixing at least two types of crystalline silica powders having different α-β phase transition initiation temperatures (step (i)). In the manufacturing method according to the present embodiment, the at least two types of crystalline silica powders mixed in step (i) each have an α-cristobalite phase relative to the total amount (100% by mass) of the crystalline phase and the amorphous phase. The proportion is 30% by mass or more. Further, the method for producing an inorganic powder according to the present embodiment may include preparing at least two types of crystalline silica powders having different α-β phase transition start temperatures (step (i')). Details of the manufacturing method including step (i') and step (i) will be described below.
＜工程（ｉ’）：結晶質シリカ粉末の準備工程＞
　本実施形態における無機粉末の製造方法は、α－β相転移開始温度が異なる少なくとも２種類の結晶質シリカ粉末を準備する工程（ｉ’）を含んでいてもよい。
　α－β相転移開始温度が異なる少なくとも２種類の結晶質シリカ粉末は、例えば、球状シリカ粉末に、アルカリ金属、アルカリ土類金属、第一遷移元素、アルミニウム、マグネシウム、イットリウム及びランタンから選択される少なくとも１つの金属を含む添加剤を添加して焼成することで調製できる。
　球状シリカ粉末としては、従来公知の方法で調製されたものを用いることができる。生産性の観点からは、粉末溶融法にて調製されたものが好ましい。本実施形態において、工程（ｉ’）は、粉末溶融法にて球状シリカ粉末を調製する工程を含んでいてもよい。 <Step (i'): Preparation step of crystalline silica powder>
The method for producing an inorganic powder in this embodiment may include a step (i') of preparing at least two types of crystalline silica powders having different α-β phase transition start temperatures.
At least two types of crystalline silica powders having different α-β phase transition initiation temperatures are selected from, for example, spherical silica powder, alkali metals, alkaline earth metals, first transition elements, aluminum, magnesium, yttrium, and lanthanum. It can be prepared by adding an additive containing at least one metal and firing.
As the spherical silica powder, one prepared by a conventionally known method can be used. From the viewpoint of productivity, those prepared by a powder melting method are preferable. In this embodiment, step (i') may include a step of preparing spherical silica powder by a powder melting method.
　粉末溶融法にて得られた球状シリカ粉末は、通常、非晶質の球状シリカ粉末となる。そのため、工程（ｉ’）は、非晶質の球状シリカ粉末から、α－β相転移開始温度の異なる結晶質シリカ粉末を、少なくとも２種類準備する工程であってもよい。なお本明細書において、「非晶質の球状シリカ粉末」とは、シリカ（ＳｉＯ２）純度が９８％以上であり、かつ非晶質相が全体の９５質量％以上である球状シリカ粉末のことを意味する。 Spherical silica powder obtained by the powder melting method is usually amorphous spherical silica powder. Therefore, step (i') may be a step of preparing at least two types of crystalline silica powders having different α-β phase transition initiation temperatures from amorphous spherical silica powder. In this specification, "amorphous spherical silica powder" refers to spherical silica powder with a silica (SiO 2 ) purity of 98% or more and an amorphous phase of 95% by mass or more of the total. means.
　粉末溶融法は、珪砂及び珪石等の粉砕物（以下、「粗原料」と記載することもある）を、火炎、プラズマ、電気炉、ガス炉等を用いて、粗原料の融点以上の高温条件下で、溶融球状化させる方法である。溶融雰囲気は特に限定されないが、経済的な観点からは、大気雰囲気下で行われることが好ましい。粗原料の平均粒子径（Ｄ５０）は、０．１～１００μｍが好ましく、０．２～５０μｍがより好ましく、０．３～１０μｍがさらに好ましい。 In the powder melting method, crushed materials such as silica sand and silica stone (hereinafter sometimes referred to as "crude raw materials") are heated under high temperature conditions above the melting point of the raw materials using a flame, plasma, electric furnace, gas furnace, etc. Below is a method of melting and spheroidizing. The melting atmosphere is not particularly limited, but from an economical point of view, it is preferable to carry out the melting under an air atmosphere. The average particle diameter (D50) of the crude raw material is preferably 0.1 to 100 μm, more preferably 0.2 to 50 μm, and even more preferably 0.3 to 10 μm.
　球状シリカ粉末の平均粒子径（Ｄ５０）は、同じ焼成条件（焼成温度、焼成時間）で半値幅と結晶化率が異なる複数のクリストバライト粒子を調整しやすい観点から、１～１００μｍが好ましく、１～８０μｍがより好ましい。また、その平均円形度は、最終的に得られる無機粉末の平均円形度を０．８０以上に調整しやすい観点から、０．８０以上が好ましい。 The average particle diameter (D50) of the spherical silica powder is preferably 1 to 100 μm, from the viewpoint of easy adjustment of multiple cristobalite particles with different half widths and crystallinity rates under the same firing conditions (firing temperature, firing time), and 1 to 100 μm. 80 μm is more preferable. Moreover, the average circularity is preferably 0.80 or more from the viewpoint of easily adjusting the average circularity of the finally obtained inorganic powder to 0.80 or more.
（添加剤）
　球状シリカ粉末に添加する添加剤は、アルカリ金属、アルカリ土類金属、第一遷移元素、アルミニウム、マグネシウム、イットリウム及びランタンから選択される少なくとも１つの金属を含む。このうち、アルミニウム、亜鉛、チタン、鉄、マンガン、カルシウム、ストロンチウム、バリウム、及びチタンから選択される少なくとも２種類が好ましい。添加剤としては、例えば、これらの純金属；酸化物、水酸化物等の金属化合物；金属塩等が挙げられる。このうち、酸化亜鉛、酸化チタン、酸化マグネシウム、酸化アルミニウム、炭酸カルシウム、水酸化カルシウム、炭酸ストロンチウム、水酸化ストロンチウム、炭酸バリウム、水酸化バリウム、チタン酸ストロンチウム、チタン酸バリウム、二アルミニウムマグネシウム四酸化物が好ましく、酸化アルミニウム、炭酸カルシウム、酸化チタン、炭酸ストロンチウム、及びチタン酸ストロンチウムから選択される少なくとも１つを含むことがより好ましい。
　添加剤の添加量は、結晶質シリカ粉末１００モルに対して、０．０１～１０モルが好ましく、０．１～１０モルがより好ましく、０．１～７モルがさらに好ましく、０．５～５モルが特に好ましい。 (Additive)
The additive added to the spherical silica powder contains at least one metal selected from alkali metals, alkaline earth metals, first transition elements, aluminum, magnesium, yttrium, and lanthanum. Among these, at least two selected from aluminum, zinc, titanium, iron, manganese, calcium, strontium, barium, and titanium are preferred. Examples of the additive include these pure metals; metal compounds such as oxides and hydroxides; and metal salts. Among these, zinc oxide, titanium oxide, magnesium oxide, aluminum oxide, calcium carbonate, calcium hydroxide, strontium carbonate, strontium hydroxide, barium carbonate, barium hydroxide, strontium titanate, barium titanate, aluminum magnesium tetroxide is preferred, and more preferably contains at least one selected from aluminum oxide, calcium carbonate, titanium oxide, strontium carbonate, and strontium titanate.
The amount of the additive added is preferably 0.01 to 10 mol, more preferably 0.1 to 10 mol, even more preferably 0.1 to 7 mol, and even more preferably 0.5 to 7 mol, per 100 mol of crystalline silica powder. Particularly preferred is 5 mol.
（焼成条件）
　焼成温度は、半値幅と結晶化率の異なる複数の結晶質シリカ粉末が得られやすい観点から、１０００～１６５０℃が好ましく、１２００～１６００℃がより好ましく、１３００～１５００℃がさらに好ましい。また焼成時間は、クリストバライト化と生産性の観点から、１～２４時間が好ましく、３～１５時間がより好ましく、４～１２時間がさらに好ましい。 (Firing conditions)
The firing temperature is preferably 1000 to 1650°C, more preferably 1200 to 1600°C, and even more preferably 1300 to 1500°C, from the viewpoint of easily obtaining a plurality of crystalline silica powders having different half widths and crystallization rates. The firing time is preferably 1 to 24 hours, more preferably 3 to 15 hours, and even more preferably 4 to 12 hours, from the viewpoint of cristobalite formation and productivity.
　球状シリカ粉末を上記の条件で焼成したのち、必要に応じて、解砕、分級、洗浄、及び乾燥を行って、結晶質シリカ粉末とすることができる。なお、工程（ｉ’）において、添加剤の種類、添加量、焼成温度、焼成時間、及び原料の球状シリカ粉末の粒子径から選択される少なくとも１つの条件を変更することにより、結晶質シリカ粉末の結晶化率、α－クリストバライト相の割合、及びα－β相転移開始温度を調整できる。例えば、焼成温度の条件を１０００～１６５０℃とすることにより、結晶化率が３０質量％以上、好ましくは５０質量％以上の結晶質シリカ粉末を得てもよい。また、焼成時間の条件を１～２４時間とすることにより、結晶相及び非晶質相の合計量（１００質量％）に対するα－クリストバライト相の割合が３０質量％以上、好ましくは５０質量％以上の結晶質シリカ粉末を得てもよい。 After the spherical silica powder is fired under the above conditions, it can be crushed, classified, washed, and dried as necessary to obtain crystalline silica powder. In addition, in step (i'), crystalline silica powder The crystallization rate of , the proportion of α-cristobalite phase, and the α-β phase transition initiation temperature can be adjusted. For example, by setting the firing temperature to 1000 to 1650°C, crystalline silica powder having a crystallinity of 30% by mass or more, preferably 50% by mass or more may be obtained. Furthermore, by setting the firing time condition to 1 to 24 hours, the ratio of the α-cristobalite phase to the total amount (100 mass%) of the crystalline phase and the amorphous phase is 30% by mass or more, preferably 50% by mass or more. Crystalline silica powder may be obtained.
　また、添加剤として酸化アルミニウムを用いる場合、焼成温度の条件を１２００～１６５０℃とすることにより、α－β相転移開始温度が１７０～２８０℃の結晶質シリカ粉末を得てもよい。また、酸化アルミニウムの添加量を、原料の球状シリカ粉末１００モルに対して、１モル以下とすることで、半値幅の狭い結晶質シリカ粉末を得ても良い。また前記添加量を１モル超とすることで、半値幅が広い結晶質シリカ粉末を得ても良い。半値幅を狭く調整すると、結晶質シリカ粉末のＴＭＡ曲線が、狭い温度領域で非常に強い熱膨張挙動を示しやすくなる。一方、半値幅を広げると、得られた結晶質シリカ粉末のＤＳＣ曲線において、広い温度領域にα－β相転移に伴う複数の吸熱ピークを有しやすい。このような結晶質シリカ粉末を含む無機粉末は、マイルドな熱膨張挙動を示すＴＭＡ曲線となりやすく、熱膨張係数も低くなりやすい。 Furthermore, when aluminum oxide is used as an additive, crystalline silica powder having an α-β phase transition starting temperature of 170 to 280°C may be obtained by setting the firing temperature to 1200 to 1650°C. Furthermore, crystalline silica powder with a narrow half width may be obtained by adding aluminum oxide in an amount of 1 mole or less per 100 moles of spherical silica powder as a raw material. Further, by setting the amount added to more than 1 mol, a crystalline silica powder having a wide half width may be obtained. When the half width is adjusted narrowly, the TMA curve of the crystalline silica powder tends to exhibit very strong thermal expansion behavior in a narrow temperature range. On the other hand, when the half-width is widened, the DSC curve of the obtained crystalline silica powder tends to have multiple endothermic peaks associated with α-β phase transition in a wide temperature range. Inorganic powder containing such crystalline silica powder tends to have a TMA curve showing mild thermal expansion behavior, and also tends to have a low coefficient of thermal expansion.
　添加剤として炭酸カルシウムを用いる場合、焼成温度の条件を１２００～１６００℃とすることにより、α－β相転移開始温度が１７０～２８０℃の結晶質シリカ粉末が得られやすくなる。 When calcium carbonate is used as an additive, by setting the firing temperature to 1200 to 1600°C, it becomes easier to obtain crystalline silica powder with an α-β phase transition starting temperature of 170 to 280°C.
　添加剤としてチタン酸ストロンチウムを用いる場合、焼成温度の条件を１２００～１６５０℃とすることにより、α－β相転移開始温度が１７０～２８０℃の結晶質シリカ粉末が得られやすくなる。また、チタン酸ストロンチウムの添加量を、原料の球状シリカ粉末１００モルに対して、１モル以下、好ましくは０．５モル以下とすることで、半値幅の狭い結晶質シリカ粉末を得ても良い。また、前記添加量を１モル超とすることで、半値幅が広い結晶質シリカ粉末を得ても良い。 When using strontium titanate as an additive, by setting the firing temperature condition to 1200 to 1650°C, it becomes easier to obtain crystalline silica powder with an α-β phase transition starting temperature of 170 to 280°C. Furthermore, crystalline silica powder with a narrow half-value width may be obtained by adding strontium titanate in an amount of 1 mol or less, preferably 0.5 mol or less, per 100 mol of spherical silica powder as a raw material. . Further, by setting the amount added to more than 1 mol, a crystalline silica powder having a wide half width may be obtained.
　また、製造工程において焼成温度、焼成時間、添加剤を同じ条件にして、原料の球状シリカ粉末の平均粒子径（Ｄ５０）を変更することにより、結晶化率が３０質量％以上、好ましくは５０質量％以上の結晶質シリカ粉末を同時に得てもよい。球状シリカ粉末はその平均粒子径（Ｄ５０）が小さいものほど結晶化しやすく、大きいものほど結晶化しにくい。その性質を利用することで、製造条件は同一で、半値幅やα－β相転移開始温度の異なる結晶質シリカ粉末を同時に複数得てもよい。 In addition, by changing the average particle diameter (D50) of the raw material spherical silica powder while keeping the firing temperature, firing time, and additives the same in the manufacturing process, the crystallization rate can be increased to 30% by mass or more, preferably 50% by mass. % or more of crystalline silica powder may be obtained at the same time. The smaller the average particle diameter (D50) of spherical silica powder, the easier it is to crystallize, and the larger the average particle diameter (D50), the more difficult it is to crystallize. By utilizing this property, it is possible to simultaneously obtain a plurality of crystalline silica powders having different half-widths and α-β phase transition start temperatures under the same manufacturing conditions.
＜工程（ｉ）：結晶質シリカ粉末の混合工程＞
　工程（ｉ）は、α－β相転移開始温度が異なる少なくとも２種類の結晶質シリカ粉末を混合する工程である。結晶質シリカ粉末を混合する方法としては、従来公知の方法、例えば、粉体混合機、ミキサー等を採用できる。混合条件としては、例えば、室温下、１～６０分間混合してもよい。
　また、工程（ｉ）は、１７０～２８０℃のα－β相転移開始温度を有する、少なくとも２種類の結晶質シリカ粉末を混合する工程であってもよい。一態様においては、最も低いα－β相転移開始温度（ＴＡ）を有する結晶質シリカ粉末（Ａ）と、最も高いα－β相転移開始温度（ＴＢ）を有する結晶質シリカ粉末（Ｂ）との温度差（ＴＢ－ＴＡ）が、９０℃以下となるように、２種類以上の結晶質シリカ粉末を混合する工程であってもよい。また、結晶質シリカ粉末（Ａ）の（ＴＡ）は、１７０～２５０℃であってもよく、２００～２５０℃あってもよい。また、結晶質シリカ粉末（Ｂ）の（ＴＢ）は、２００～２８０℃であってもよく、２００～２６０℃であってもよい。
　また、混合する複数の結晶質シリカ粉末の平均粒子径（Ｄ５０）は１００μｍ以下であれば、同程度の粒子径であってもよく、異なる粒子径であってもよい。樹脂配合時の流動性の観点からは、平均粒子径（Ｄ５０）が異なる複数の結晶質シリカ粉末を混合させることが好ましい。 <Step (i): Mixing step of crystalline silica powder>
Step (i) is a step of mixing at least two types of crystalline silica powders having different α-β phase transition initiation temperatures. As a method for mixing the crystalline silica powder, conventionally known methods such as a powder mixer, mixer, etc. can be employed. As for the mixing conditions, for example, mixing may be performed at room temperature for 1 to 60 minutes.
Further, step (i) may be a step of mixing at least two types of crystalline silica powders having an α-β phase transition initiation temperature of 170 to 280°C. In one embodiment, a crystalline silica powder (A) having the lowest α-β phase transition onset temperature (TA) and a crystalline silica powder (B) having the highest α-β phase transition onset temperature (TB). It may be a step of mixing two or more types of crystalline silica powder so that the temperature difference (TB-TA) is 90° C. or less. Further, (TA) of the crystalline silica powder (A) may be at a temperature of 170 to 250°C, or may be 200 to 250°C. Further, (TB) of the crystalline silica powder (B) may be at a temperature of 200 to 280°C, or may be 200 to 260°C.
Moreover, as long as the average particle diameter (D50) of the plurality of crystalline silica powders to be mixed is 100 μm or less, the particle diameters may be the same or may be different. From the viewpoint of fluidity during resin compounding, it is preferable to mix a plurality of crystalline silica powders having different average particle diameters (D50).
　前述の工程（ｉ）を含む方法により（必要に応じて、工程（ｉ’）及び工程（ｉ）を含む方法により）、本実施形態に係る無機粉末を調製できる。なお、工程（ｉ）の後、必要に応じて、無機粉末を表面処理剤で表面処理してもよい。 The inorganic powder according to the present embodiment can be prepared by the method including the above-mentioned step (i) (if necessary, by the method including step (i') and step (i)). Note that after step (i), the inorganic powder may be surface-treated with a surface-treating agent, if necessary.
［用途］
　本実施形態に係る無機粉末は、従来のクリストバライト粉末よりも低い熱膨張係数を有し、かつ高熱膨張率を達成できる。そのため、本実施形態に係る無機粉末を樹脂に充填して、封止材用フィラーとして用いることもできる。以下、本実施形態に係る無機粉末を含む樹脂組成物について説明する。 [Application]
The inorganic powder according to this embodiment has a lower coefficient of thermal expansion than conventional cristobalite powder, and can achieve a high coefficient of thermal expansion. Therefore, the inorganic powder according to this embodiment can be filled into a resin and used as a filler for a sealing material. Hereinafter, a resin composition containing an inorganic powder according to this embodiment will be explained.
［樹脂組成物］
　本実施形態に係る樹脂組成物は、前述の無機粉末と、熱可塑性樹脂及び熱硬化性樹脂から選択される少なくとも１つの樹脂とを含む。
　樹脂組成物中の無機粉末の含有量は特に限定されず、目的に応じて適宜調整し得る。例えば、耐熱性、熱膨張係数等の観点からは、樹脂組成物中の無機粉末の割合は、樹脂組成物の総質量に対して、４０～９０質量％が好ましく、７０～９０質量％がより好ましい。 [Resin composition]
The resin composition according to this embodiment includes the above-mentioned inorganic powder and at least one resin selected from thermoplastic resins and thermosetting resins.
The content of inorganic powder in the resin composition is not particularly limited and can be adjusted as appropriate depending on the purpose. For example, from the viewpoint of heat resistance, coefficient of thermal expansion, etc., the proportion of inorganic powder in the resin composition is preferably 40 to 90% by mass, more preferably 70 to 90% by mass, based on the total mass of the resin composition. preferable.
＜樹脂＞
　本実施形態に係る樹脂組成物は、熱可塑性樹脂及び熱硬化性樹脂から選択される少なくとも１つの樹脂を含む。熱可塑性樹脂としては、例えば、ポリエチレン樹脂；ポリプロピレン樹脂等が挙げられる。熱硬化性樹脂としては、例えば、エポキシ樹脂；シリコーン樹脂；フェノール樹脂；メラミン樹脂；ユリア樹脂；不飽和ポリエステル樹脂；フッ素樹脂；ポリイミド樹脂、ポリアミドイミド樹脂、ポリエーテルイミド樹脂等のポリアミド系樹脂；ポリブチレンテレフタレート樹脂、ポリエチレンテレフタレート樹脂等のポリエステル系樹脂；ポリフェニレンスルフィド樹脂；全芳香族ポリエステル樹脂；ポリスルホン樹脂；液晶ポリマー樹脂；ポリエーテルスルホン樹脂；ポリカーボネート樹脂；マレイミド変性樹脂；ＡＢＳ樹脂；ＡＡＳ（アクリロニトリル－アクリルゴム－スチレン）樹脂；ＡＥＳ（アクリロニトリル－エチレン－プロピレン－ジエンゴム－スチレン）樹脂；炭化水素系エラストマー樹脂；ポリフェニレンエーテル樹脂；芳香族ポリエン系樹脂等が挙げられる。これらの樹脂は１種単独で用いられてもよく、２種以上を併用してもよい。このうち、本実施形態に係る樹脂組成物を半導体封止材用分野に用いる場合、樹脂としては熱硬化性樹脂が好ましく、エポキシ樹脂を含むことがより好ましい。 <Resin>
The resin composition according to this embodiment includes at least one resin selected from thermoplastic resins and thermosetting resins. Examples of the thermoplastic resin include polyethylene resin; polypropylene resin, and the like. Examples of thermosetting resins include epoxy resins; silicone resins; phenolic resins; melamine resins; urea resins; unsaturated polyester resins; fluororesins; polyamide resins such as polyimide resins, polyamideimide resins, and polyetherimide resins; Polyester resins such as butylene terephthalate resin and polyethylene terephthalate resin; polyphenylene sulfide resin; wholly aromatic polyester resin; polysulfone resin; liquid crystal polymer resin; polyether sulfone resin; polycarbonate resin; maleimide modified resin; ABS resin; AAS (acrylonitrile-acrylic Examples include rubber-styrene resin; AES (acrylonitrile-ethylene-propylene-diene rubber-styrene) resin; hydrocarbon elastomer resin; polyphenylene ether resin; aromatic polyene resin. These resins may be used alone or in combination of two or more. Among these, when the resin composition according to the present embodiment is used in the field of semiconductor sealing materials, the resin is preferably a thermosetting resin, and more preferably contains an epoxy resin.
　エポキシ樹脂としては、特に限定されず、例えば、フェノールノボラック型エポキシ樹脂、オルソクレゾールノボラック型エポキシ樹脂、フェノール類とアルデヒド類のノボラック樹脂をエポキシ化したもの、ビスフェノールＡ、ビスフェノールＦ及びビスフェノールＳなどのグリシジルエーテル型エポキシ樹脂、フタル酸やダイマー酸などの多塩基酸とエポクロルヒドリンとの反応により得られるグリシジルエステル酸エポキシ樹脂（ビスフェノール型エポキシ樹脂）、線状脂肪族エポキシ樹脂、脂環式エポキシ樹脂、複素環式エポキシ樹脂、アルキル変性多官能エポキシ樹脂、β－ナフトールノボラック型エポキシ樹脂、１，６－ジヒドロキシナフタレン型エポキシ樹脂、２，７－ジヒドロキシナフタレン型エポキシ樹脂、ビスヒドロキシビフェニル型エポキシ樹脂、難燃性を付与するために臭素などのハロゲンを導入したエポキシ樹脂等が挙げられる。これらは１種単独で用いられてもよく、２種以上を併用してもよい。このうち、ビスフェノールＡ、ビスフェノールＦ等のグリシジルエーテル型エポキシ樹脂、及び脂環式エポキシ樹脂から選択される少なくとも１つのエポキシ樹脂を含むことがより好ましい。 Epoxy resins are not particularly limited, and include, for example, phenol novolac type epoxy resins, orthocresol novolac type epoxy resins, epoxidized novolak resins of phenols and aldehydes, and glycidyl resins such as bisphenol A, bisphenol F, and bisphenol S. Ether type epoxy resin, glycidyl ester acid epoxy resin (bisphenol type epoxy resin) obtained by reaction of polybasic acid such as phthalic acid or dimer acid with epochlorohydrin, linear aliphatic epoxy resin, alicyclic epoxy resin , heterocyclic epoxy resin, alkyl-modified polyfunctional epoxy resin, β-naphthol novolac type epoxy resin, 1,6-dihydroxynaphthalene type epoxy resin, 2,7-dihydroxynaphthalene type epoxy resin, bishydroxybiphenyl type epoxy resin, Examples include epoxy resins into which halogens such as bromine are introduced to impart flammability. These may be used alone or in combination of two or more. Among these, it is more preferable to include at least one epoxy resin selected from glycidyl ether type epoxy resins such as bisphenol A and bisphenol F, and alicyclic epoxy resins.
（硬化剤）
　樹脂としてエポキシ樹脂を含む場合、樹脂組成物はさらに硬化剤を含むことが好ましい。硬化剤としては、例えば、フェノール、クレゾール、キシレノール、レゾルシノール、クロロフェノール、ｔ－ブチルフェノール、ノニルフェノール、イソプロピルフェノール、オクチルフェノール等の群から選択される少なくとも１種を、ホルムアルデヒド、パラホルムアルデヒド又はパラキシレンとともに酸化触媒下で反応させて得られるノボラック型樹脂、ポリパラヒドロキシスチレン樹脂、ビスフェノールＡやビスフェノールＳ等のビスフェノール化合物、ピロガロールやフロログルシノール等の３官能フェノール類、無水マレイン酸、無水フタル酸や無水ピロメリット酸等の酸無水物、メタフェニレンジアミン、ジアミノジフェニルメタン、ジアミノジフェニルスルホン等の芳香族アミン等が挙げられる。これら硬化剤は１種単独で用いられてもよく、２種以上を併用してもよい。 (hardening agent)
When containing an epoxy resin as the resin, it is preferable that the resin composition further contains a curing agent. As the curing agent, for example, at least one selected from the group of phenol, cresol, xylenol, resorcinol, chlorophenol, t-butylphenol, nonylphenol, isopropylphenol, octylphenol, etc., is used together with formaldehyde, paraformaldehyde, or paraxylene as an oxidation catalyst. Novolac type resin obtained by the reaction below, polyparahydroxystyrene resin, bisphenol compounds such as bisphenol A and bisphenol S, trifunctional phenols such as pyrogallol and phloroglucinol, maleic anhydride, phthalic anhydride, and pyromellitic anhydride. Examples include acid anhydrides such as acids, aromatic amines such as metaphenylene diamine, diaminodiphenylmethane, and diaminodiphenylsulfone. These curing agents may be used alone or in combination of two or more.
　硬化剤の含有量は、エポキシ樹脂のエポキシ当量１に対して、硬化剤の活性水素当量（又は酸無水物当量）が０．０１～１．２５になるように配合することが好ましい。 The content of the curing agent is preferably blended so that the active hydrogen equivalent (or acid anhydride equivalent) of the curing agent is 0.01 to 1.25 per 1 epoxy equivalent of the epoxy resin.
　（その他の添加剤）
　樹脂組成物には、本発明の効果を阻害しない範囲で、硬化促進剤、離型剤、カップリング剤、着色剤等を配合することができる。
　硬化促進剤としては、特に限定されず、１，８－ジアザビシクロ（５，４，０）ウンデセン－７、トリフェニルホスフィン、ベンジルジメチルアミン、２－メチルイミダゾール等が挙げられる。
　離型剤としては、天然ワックス類、合成ワックス類、直鎖脂肪酸の金属塩、酸アミド類、エステル類、パラフィン等が挙げられる。
　カップリング剤としては、シランカップリング剤が挙げられる。シランカップリング剤としては、例えば、γ－グリシドキシプロピルトリメトキシシラン、β－（３，４－エポキシシクロヘキシル）エチルトリメトキシシラン等のエポキシシラン；アミノプロピルトリエトキシシラン、ウレイドプロピルトリエトキシシラン、Ｎ－フェニルアミノプロピルトリメトキシシラン等のアミノシラン；フェニルトリメトキシシラン、メチルトリメトキシシラン、オクタデシルトリメトキシシラン等の疎水性シラン化合物やメルカプトシラン等が挙げられる。 (Other additives)
The resin composition may contain a curing accelerator, a mold release agent, a coupling agent, a coloring agent, etc. within a range that does not impede the effects of the present invention.
The curing accelerator is not particularly limited, and examples thereof include 1,8-diazabicyclo(5,4,0)undecene-7, triphenylphosphine, benzyldimethylamine, 2-methylimidazole, and the like.
Examples of the mold release agent include natural waxes, synthetic waxes, metal salts of straight chain fatty acids, acid amides, esters, paraffin, and the like.
Examples of the coupling agent include silane coupling agents. Examples of the silane coupling agent include epoxysilanes such as γ-glycidoxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; aminopropyltriethoxysilane, ureidopropyltriethoxysilane, Aminosilanes such as N-phenylaminopropyltrimethoxysilane; hydrophobic silane compounds such as phenyltrimethoxysilane, methyltrimethoxysilane, octadecyltrimethoxysilane, and mercaptosilane.
＜樹脂組成物の製造方法＞
　本実施形態に係る樹脂組成物を製造する方法としては、特に限定されず、各材料の所定量を撹拌、溶解、混合、分散させることにより製造することができる。これらの混合物の混合、撹拌、分散等の装置は特に限定されないが、撹拌、加熱装置を備えたライカイ機、３本ロールミル、ボールミル、プラネタリーミキサー等を用いることができる。またこれらの装置を適宜組み合わせて使用してもよい。 <Method for manufacturing resin composition>
The method for producing the resin composition according to the present embodiment is not particularly limited, and can be produced by stirring, dissolving, mixing, or dispersing predetermined amounts of each material. Apparatus for mixing, stirring, dispersing, etc. these mixtures is not particularly limited, but a Raikai machine equipped with a stirring and heating device, a three-roll mill, a ball mill, a planetary mixer, etc. can be used. Further, these devices may be used in appropriate combination.
　上述の通り、本実施形態に係る樹脂組成物は、従来の球状クリストバライト粉末のような熱膨張挙動を示さず、かつ高熱膨張率の無機粉末を含んでいる。そのため、本実施形態に係る樹脂組成物を封止材に用いた場合、より取り扱いが容易であり、かつ半導体デバイスの反りやクラックを防止できる。また、本実施形態に係る樹脂組成物は、低粘度であるため流動性がよく、成形性にも優れている。 As described above, the resin composition according to the present embodiment contains an inorganic powder that does not exhibit thermal expansion behavior like conventional spherical cristobalite powder and has a high coefficient of thermal expansion. Therefore, when the resin composition according to this embodiment is used as a sealing material, it is easier to handle and it is possible to prevent warping and cracking of the semiconductor device. Furthermore, the resin composition according to the present embodiment has low viscosity and therefore has good fluidity and excellent moldability.
　以下、実施例を示して本発明を詳細に説明するが、本発明は以下の記載によって限定されるものではない。 Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following description.
＜結晶質シリカ粉末１の調製＞
　粉末溶融法にて調製された非晶質の球状シリカ粉末（デンカ（株）製、製品名「ＦＢ－４０Ｒ」、平均粒子径：４１．０μｍ）１００モルに、炭酸カルシウム（（株）宇部マテリアルズ製、製品名「ＣＳ　３Ｎ－Ａ」）を１モル添加して、低周波共振音響ミキサー（Ｒｅｓｏｄｙｎ社製）を用いて３分間混合した。その後、雰囲気式高速昇温電気炉（（株）モトヤマ製、製品名「ＮＬＡ－２０２５Ｄ－ＳＰ」）に前記混合物を投入し、１３００℃で１２時間焼成して、結晶質シリカ粉末１を得た。得られた結晶質シリカ粉末１の結晶相の割合、結晶相の組成、α－β相転移開始温度、平均円形度、平均粒子径（Ｄ５０）、比表面積、及び平均粒子密度を以下の条件で測定した。結果を表１に示す。 <Preparation of crystalline silica powder 1>
Calcium carbonate (Ube Materials Co., Ltd.) was added to 100 mol of amorphous spherical silica powder (manufactured by Denka Co., Ltd., product name "FB-40R", average particle size: 41.0 μm) prepared by a powder melting method. 1 mole of CS 3N-A (manufactured by Resodyn Co., Ltd.) was added and mixed for 3 minutes using a low frequency resonant acoustic mixer (manufactured by Resodyn Co., Ltd.). Thereafter, the mixture was placed in an atmospheric high-speed heating electric furnace (manufactured by Motoyama Co., Ltd., product name "NLA-2025D-SP") and fired at 1300°C for 12 hours to obtain crystalline silica powder 1. . The crystalline phase ratio, crystalline phase composition, α-β phase transition initiation temperature, average circularity, average particle diameter (D50), specific surface area, and average particle density of the obtained crystalline silica powder 1 were determined under the following conditions. It was measured. The results are shown in Table 1.
（結晶質シリカ粉末の結晶相の割合及び結晶相の組成分析）
　結晶質シリカ粉末の結晶相の組成をＸＲＤ回折測定より確認した。具体的には、ＸＲＤ装置（（株）リガク製、製品名「ＲＩＮＴ－ＵｌｔｉｍａＩＶ」）を用いて、以下の条件で結晶質シリカ粉末のＸ線回折ピークを測定した。
　Ｘ線源：ＣｕＫα
　管電圧：４０ｋＶ
　管電流：４０ｍＡ
　スキャン速度：４．０°／ｍｉｎ
　２θスキャン範囲：１０°～５０°
　その後、結晶質シリカ粉末で検出された各結晶相のピークの積分強度（Ｉｑ、Ｉｃ、Ｉｔ）と各結晶相の標準試料のピークの積分強度（Ｓｑ、Ｓｃ、Ｓｔ）を用いて、下記式（１）～（４）より各結晶相の割合及び結晶相の割合を算出した。
　（石英相の割合）＝ΣＩｑ／ΣＳｑ×１００　・・・（１）
　（α－クリストバライト相の割合）＝ΣＩｃ／ΣＳｃ×１００　・・・（２）
　（トリジマイト相の割合）＝ΣＩｔ／ΣＳｔ×１００　・・・（３）
　（結晶相の割合）＝（石英相の割合）＋（クリストバライト相の割合）＋（トリジマイト相の割合）　・・・（４）
　なお、式（１）～（４）中、Σはある特定の結晶相の複数のピークの積分強度の和を示す。また、ｑは石英相、ｃはα－クリストバライト相、ｔはトリジマイト相を示す。なお、結晶質シリカ粉末の全組成（１００質量％）から、式（４）で算出された結晶相の割合を差し引いた値を、非晶質相の割合とした。 (Ratio of crystal phase and composition analysis of crystal phase of crystalline silica powder)
The composition of the crystal phase of the crystalline silica powder was confirmed by XRD diffraction measurement. Specifically, the X-ray diffraction peak of the crystalline silica powder was measured using an XRD apparatus (manufactured by Rigaku Co., Ltd., product name "RINT-Ultima IV") under the following conditions.
X-ray source: CuKα
Tube voltage: 40kV
Tube current: 40mA
Scan speed: 4.0°/min
2θ scan range: 10° to 50°
Then, using the integrated intensity of the peak of each crystalline phase detected in the crystalline silica powder (Iq, Ic, It) and the integrated intensity of the peak of the standard sample of each crystalline phase (Sq, Sc, St), the following formula is calculated. The ratio of each crystal phase and the ratio of crystal phases were calculated from (1) to (4).
(Percentage of quartz phase) = ΣIq / ΣSq × 100 ... (1)
(α-cristobalite phase ratio) = ΣIc/ΣSc×100 (2)
(Ratio of tridymite phase)=ΣIt/ΣSt×100 (3)
(Ratio of crystal phase) = (Ratio of quartz phase) + (Ratio of cristobalite phase) + (Ratio of tridymite phase) ... (4)
Note that in formulas (1) to (4), Σ represents the sum of integrated intensities of a plurality of peaks of a particular crystal phase. Furthermore, q represents a quartz phase, c represents an α-cristobalite phase, and t represents a tridymite phase. Note that the value obtained by subtracting the ratio of the crystalline phase calculated by formula (4) from the total composition (100% by mass) of the crystalline silica powder was defined as the ratio of the amorphous phase.
（結晶質シリカ粉末のＤＳＣの測定）
　結晶質シリカ粉末５０ｍｇを、示差走査熱量計（ネッチ・ジャパン（株）製、製品名「ＳＴＡ４４９Ｆ３　Ｊｕｐｉｔｅｒ（登録商標）」）により、昇温速度１０℃／分の条件で大気雰囲気下（パージ：Ａｉｒ　５０ｍＬ／ｍｉｎ、プロテクティブ：Ｎ２　２０ｍＬ／ｍｉｎ）、室温から３００℃まで結晶質シリカ粉末を昇温してＤＳＣ曲線を得た。クリストバライトの相転移は吸熱ピークとして現れるため、図２のように、ＤＳＣ曲線の吸熱ピークの開始温度のベースラインの傾きに沿ってラインＬ１を引き、次に、吸熱ピークの最初の変曲点に沿って引いたラインとの交点（開始点１）の温度を「α－β相転移開始温度」とした。なお、得られたＤＳＣ曲線からα－β相転移終了温度、及びα－β相転移ピークトップ温度も求めた。「α－β相転移終了温度」は、図２に示すように、ＤＳＣ曲線の終了温度のベースラインの傾きに沿ってラインＬ２を引き、次に吸熱ピークの最後の変曲点に沿って引いたラインとの交点（終了点２）から求めた。また「α－β相転移ピークトップ温度」は、吸熱ピークのピークトップ温度から求めた。 (DSC measurement of crystalline silica powder)
50 mg of crystalline silica powder was heated in an air atmosphere (purge: Air) using a differential scanning calorimeter (manufactured by Netch Japan Co., Ltd., product name "STA449F3 Jupiter (registered trademark)") at a heating rate of 10° C./min. A DSC curve was obtained by heating the crystalline silica powder from room temperature to 300° C. (50 mL/min, protective: N 2 20 mL/min). Since the phase transition of cristobalite appears as an endothermic peak, as shown in Figure 2, draw a line L1 along the slope of the baseline of the starting temperature of the endothermic peak in the DSC curve, and then draw the line L1 at the first inflection point of the endothermic peak. The temperature at the point of intersection (starting point 1) with the line drawn along the line was defined as the "α-β phase transition starting temperature." Note that the α-β phase transition end temperature and the α-β phase transition peak top temperature were also determined from the obtained DSC curve. As shown in Figure 2, the "α-β phase transition end temperature" is calculated by drawing a line L2 along the slope of the baseline of the end temperature of the DSC curve, and then drawing it along the last inflection point of the endothermic peak. It was determined from the intersection with the line (end point 2). Further, the "α-β phase transition peak top temperature" was determined from the peak top temperature of the endothermic peak.
（平均円形度の測定）
　結晶質シリカ粉末をカーボンテープで固定した後、オスミウムコーティングを行った。その後、走査型電子顕微鏡（日本電子（株）製、製品名：ＪＳＭ－７００１Ｆ　ＳＨＬ）を用いて、倍率２００～５０，０００倍で粒子を撮影し、画像解析装置（日本ローパー（株）製、製品名：Ｉｍａｇｅ－Ｐｒｏ　Ｐｒｅｍｉｅｒ　Ｖｅｒ．９．３）を用いて、粒子の投影面積（Ｓ）と投影周囲長（Ｌ）を算出してから、下記の式（９）より円形度を算出した。任意の２００個の粒子について円形度を算出してその平均値を、結晶質シリカ粉末の平均円形度とした。
　円形度＝４πＳ／Ｌ２　・・・（９） (Measurement of average circularity)
After fixing the crystalline silica powder with carbon tape, osmium coating was performed. Thereafter, the particles were photographed using a scanning electron microscope (manufactured by JEOL Co., Ltd., product name: JSM-7001F SHL) at a magnification of 200 to 50,000 times, and an image analysis device (manufactured by Nippon Roper Co., Ltd., product name: JSM-7001F SHL) was used. After calculating the projected area (S) and projected perimeter (L) of the particles using Image-Pro Premier Ver. 9.3 (product name: Image-Pro Premier Ver. 9.3), the degree of circularity was calculated using the following formula (9). The circularity was calculated for 200 arbitrary particles, and the average value was taken as the average circularity of the crystalline silica powder.
Circularity = 4πS/L 2 ...(9)
（比表面積の測定方法）
　測定用セルに結晶質シリカ粉末を１ｇ充填し、全自動比表面積径測定装置（Ｍｏｕｎｔｅｃｈ社製、製品名：Ｍａｃｓｏｒｂ　ＨＭ　ｍｏｄｅｌ－１２０１（ＢＥＴー点法））を用いて、結晶質シリカ粉末の比表面積を測定した。なお、測定前の脱気条件は、２００℃、１０分間とした。 (Method of measuring specific surface area)
Fill a measuring cell with 1 g of crystalline silica powder, and use a fully automatic specific surface area diameter measuring device (manufactured by Mountech, product name: Macsorb HM model-1201 (BET-point method)) to measure the ratio of crystalline silica powder. Surface area was measured. Note that the degassing conditions before measurement were 200° C. and 10 minutes.
（平均粒子径の測定方法）
　レーザー回折式粒度分布測定装置（ベックマンコールター社製、商品名：ＬＳ　１３　３２０）を用いて平均粒子径の測定を行った。まず、ガラスビーカーに５０ｃｍ３の純水と、結晶質シリカ粉末０．１ｇとを入れ、超音波ホモジナイザー（ＢＲＡＮＳＯＮ社製、商品名：ＳＦＸ２５０）で１分間、分散処理を行った。分散処理を行った結晶質シリカ粉末の分散液を、レーザー回折式粒度分布測定装置にスポイトで一滴ずつ添加し、所定量添加してから３０秒後に測定を行った。レーザー回折式粒度分布測定装置内のセンサーで検出した結晶質シリカ粉末の回折／散乱光の光強度分布のデータから、粒度分布を計算した。平均粒子径は、測定される粒子径の体積基準の累積粒度分布において、累積値が５０％に相当する粒子径から算出した。 (Method for measuring average particle diameter)
The average particle diameter was measured using a laser diffraction particle size distribution analyzer (manufactured by Beckman Coulter, trade name: LS 13 320). First, 50 cm 3 of pure water and 0.1 g of crystalline silica powder were placed in a glass beaker, and dispersed for 1 minute using an ultrasonic homogenizer (trade name: SFX250, manufactured by BRANSON). The dispersion of crystalline silica powder subjected to the dispersion treatment was added drop by drop to a laser diffraction type particle size distribution measuring device using a dropper, and measurements were performed 30 seconds after adding a predetermined amount. The particle size distribution was calculated from the data of the light intensity distribution of the diffraction/scattered light of the crystalline silica powder detected by the sensor in the laser diffraction type particle size distribution measuring device. The average particle diameter was calculated from the particle diameter corresponding to a cumulative value of 50% in the volume-based cumulative particle size distribution of the measured particle diameter.
（平均粒子密度の測定方法）
　結晶質シリカ粉末２．０ｇを測定用試料セルに入れ、乾式密度計（（株）島津製作所製、製品名：アキュピックＩＩ　１３４０）を用い、気体（ヘリウム）置換法により平均粒子密度を測定した。 (Method of measuring average particle density)
2.0 g of crystalline silica powder was placed in a measurement sample cell, and the average particle density was measured by a gas (helium) displacement method using a dry density meter (manufactured by Shimadzu Corporation, product name: Accupic II 1340).
＜結晶質シリカ粉末２～１２の調製＞
　非晶質の球状シリカ粉末に配合する添加剤、焼成温度及び焼成時間を表１に示す通りとした以外は、結晶質シリカ粉末１と同じ方法で結晶質シリカ粉末２～１２を調製した。なお、結晶質シリカ粉末７～９は非晶質の球状シリカ粉末として、デンカ（株）製、製品名「ＦＢ－５Ｄ」（平均粒子径（Ｄ５０）：４．７μｍ）を用いた。また各結晶質シリカ粉末について、結晶質シリカ粉末１と同じ方法で、結晶相の割合、結晶相の組成、α－β相転移開始温度、平均円形度、平均粒子径、比表面積、及び平均粒子密度を測定した。結果を表１に示す。 <Preparation of crystalline silica powders 2 to 12>
Crystalline silica powders 2 to 12 were prepared in the same manner as crystalline silica powder 1, except that the additives added to the amorphous spherical silica powder, the firing temperature, and the firing time were as shown in Table 1. For crystalline silica powders 7 to 9, amorphous spherical silica powder manufactured by Denka Co., Ltd. under the product name "FB-5D" (average particle diameter (D50): 4.7 μm) was used. For each crystalline silica powder, the ratio of crystal phase, composition of crystal phase, α-β phase transition initiation temperature, average circularity, average particle diameter, specific surface area, and average particle size were determined using the same method as for crystalline silica powder 1. The density was measured. The results are shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
［実施例１～８］
　表２に示す配合で結晶質シリカ粉末を混合して、無機粉末を調製した。混合条件としては、プラスチック容器に各粉末を入れ、低周波共振音響ミキサー（Ｒｅｓｏｄｙｎ社製）用いて、室温で３分間混合した。各例の無機粉末について、以下の条件で、熱膨張係数、熱膨張率、及びα－クリストバライト相の（１０１）面の半値幅を測定した。また、結晶質シリカ粉末と同じ条件で、平均粒子径、平均円形度、比表面積、及び粒子密度を測定した。結果を表２に示す。 [Examples 1 to 8]
Inorganic powder was prepared by mixing crystalline silica powder in the formulation shown in Table 2. As for mixing conditions, each powder was placed in a plastic container and mixed for 3 minutes at room temperature using a low frequency resonance acoustic mixer (manufactured by Resodyn). Regarding the inorganic powder of each example, the coefficient of thermal expansion, coefficient of thermal expansion, and half-width of the (101) plane of the α-cristobalite phase were measured under the following conditions. In addition, the average particle diameter, average circularity, specific surface area, and particle density were measured under the same conditions as for crystalline silica powder. The results are shown in Table 2.
＜熱膨張係数の測定（ＴＭＡ分析）＞
　エポキシ樹脂（三菱ケミカル（株）製、製品名「ＪＥＲ８２８」）２０．０質量部、４、４’－ジアミノジフェニルメタン５．０質量部を９５℃で溶融させながら混合し、無機粉末を体積％換算で４０％になるように加え、遊星式撹拌機（回転数２０００ｒｐｍ）にて混合した。予め加熱しておいたシリコーン製の型枠（２ｃｍ角×５ｍｍ厚）に上記混合物を流し込み、８０℃で２０分間静置し、真空加熱プレス機（（株）井元製作所製、製品名「ＩＭＣ－１６７４－Ａ型」）で、８０℃、３．０ＭＰａで１時間、１５０℃、５．０ＭＰａで１時間、２００℃、７ＭＰａで０．５時間の順でプレス加熱して硬化させた。硬化後、４ｍｍ×４ｍｍ×１５ｍｍに加工して測定用サンプルを作成し、ＴＭＡ（ブルカー社製、製品名「ＴＭＡ４０００ＳＡ」）にて熱膨張率を測定した。昇温条件は、５℃／ｍｉｎ、測定温度は－１０℃～３００℃とし、窒素雰囲気で２ｃｙｃｌｅ測定して、得られたＴＭＡ測定チャートの２ｃｙｃｌｅ目から、１７０～２７０℃の温度範囲において、１０℃毎に熱膨張係数を算出した。また、その最大値をＣＴＥｍａｘとし、最小値をＣＴＥｍｉｎとした。 <Measurement of thermal expansion coefficient (TMA analysis)>
20.0 parts by mass of epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name "JER828") and 5.0 parts by mass of 4,4'-diaminodiphenylmethane were mixed while melting at 95°C, and the inorganic powder was converted to volume %. and mixed with a planetary stirrer (rotation speed: 2000 rpm). The above mixture was poured into a preheated silicone mold (2 cm square x 5 mm thick), left to stand at 80°C for 20 minutes, and then heated using a vacuum heat press (manufactured by Imoto Seisakusho Co., Ltd., product name "IMC-"). 1674-A type) for 1 hour at 80° C. and 3.0 MPa, 1 hour at 150° C. and 5.0 MPa, and 0.5 hour at 200° C. and 7 MPa for curing. After curing, a sample for measurement was prepared by processing into a size of 4 mm x 4 mm x 15 mm, and the coefficient of thermal expansion was measured using TMA (manufactured by Bruker, product name: "TMA4000SA"). The temperature increase condition was 5°C/min, the measurement temperature was -10°C to 300°C, and the measurement was carried out for 2 cycles in a nitrogen atmosphere, and from the 2nd cycle of the obtained TMA measurement chart, in the temperature range of 170 to 270°C, 10 The thermal expansion coefficient was calculated for each °C. Further, the maximum value was defined as CTE max , and the minimum value was defined as CTE min .
＜熱膨張率の算出方法＞
　上記のＴＭＡ測定より得られたＴＭＡ曲線から、１７０～２７０℃の温度範囲の熱膨張率を算出した。 <How to calculate the coefficient of thermal expansion>
The thermal expansion coefficient in the temperature range of 170 to 270° C. was calculated from the TMA curve obtained from the above TMA measurement.
＜Ｘ線回折の測定＞
　ＸＲＤ装置（（株）リガク製、製品名「ＲＩＮＴ－ＵｌｔｉｍａＩＶ」）を用いて、以下の条件で無機粉末のＸ線回折ピークを測定して、α－クリストバライト相の（１０１面）の半値幅を算出した。
　Ｘ線源：ＣｕＫα
　管電圧：４０ｋＶ
　管電流：４０ｍＡ
　スキャン速度：４．０°／ｍｉｎ
　２θスキャン範囲：１０°～５０° <Measurement of X-ray diffraction>
Using an XRD device (manufactured by Rigaku Co., Ltd., product name "RINT-Ultima IV"), the X-ray diffraction peak of the inorganic powder was measured under the following conditions, and the half-value width of the (101 plane) of the α-cristobalite phase was determined. Calculated.
X-ray source: CuKα
Tube voltage: 40kV
Tube current: 40mA
Scan speed: 4.0°/min
2θ scan range: 10° to 50°
［比較例１～２］
　表２に示す配合で実施例と同じ条件で無機粉末を調製した。得られた無機粉末について、実施例と同じ条件で熱膨張係数、及びα－クリストバライト相の（１０１）面の半値幅を測定した。また、結晶質シリカ粉末と同じ条件で、平均粒子径、平均円形度、比表面積、及び粒子密度を測定した。結果を表３に示す。 [Comparative Examples 1-2]
Inorganic powders were prepared using the formulations shown in Table 2 under the same conditions as in the examples. Regarding the obtained inorganic powder, the thermal expansion coefficient and the half-value width of the (101) plane of the α-cristobalite phase were measured under the same conditions as in the examples. In addition, the average particle diameter, average circularity, specific surface area, and particle density were measured under the same conditions as for crystalline silica powder. The results are shown in Table 3.
［比較例３～５］
　表２に示す、結晶質シリカ粉末１２（球状クリストバライト粉末）、非晶質球状シリカ粉末及び破砕石英粉末について、実施例と同じ条件で熱膨張係数、α－クリストバライト相の（１０１）面の半値幅を測定した。結果を表３に示す。 [Comparative Examples 3 to 5]
Regarding the crystalline silica powder 12 (spherical cristobalite powder), amorphous spherical silica powder, and crushed quartz powder shown in Table 2, the thermal expansion coefficient and the half-value width of the (101) plane of the α-cristobalite phase were measured under the same conditions as in the examples. was measured. The results are shown in Table 3.
＜熱膨張係数の評価＞
　前記方法により算出された熱膨張係数の最大値（ＣＴＥｍａｘ）が小さく、かつ最大値（ＣＴＥｍａｘ）及び最小値（ＣＴＥｍｉｎ）との差（ＣＴＥｍａｘ－ＣＴＥｍｉｎ）が小さいものは、熱膨張率の急激な立ち上がりがなく、比較的リニアなＴＭＡ曲線を有するため、ハンドリング性が良好であり、かつ半田溶融時に基板と封止材との界面でクラックや割れが生じにくいと考えられる。比較例３の球状クリストバライト粉末の、前記方法により算出された熱膨張係数の最大値（ＣＴＥｍａｘ）は４９．７×１０－５／Ｋであり、さらに最小値（ＣＴＥｍｉｎ）との差（ＣＴＥｍａｘ－ＣＴＥｍｉｎ）は３８．０×１０－５／Ｋであった。そこで各例で得られた無機粉末について、１７０～２７０℃の温度範囲での熱膨張係数の最大値（ＣＴＥｍａｘ）と、最大値（ＣＴＥｍａｘ）及び最小値（ＣＴＥｍｉｎ）との差（ＣＴＥｍａｘ－ＣＴＥｍｉｎ）を算出し、以下の評価基準で評価した。結果を表２～３に示す。
　（評価基準）
　優（３点）：（ＣＴＥｍａｘ）４０×１０－５／Ｋ以下であり、かつ（ＣＴＥｍａｘ－ＣＴＥｍｉｎ）が１５×１０－５／Ｋ以下であった。
　良（２点）：（ＣＴＥｍａｘ）４０×１０－５／Ｋ以下であり、かつ（ＣＴＥｍａｘ－ＣＴＥｍｉｎ）が１５×１０－５／Ｋ超２５×１０－５／Ｋ以下であった。
　可（１点）：（ＣＴＥｍａｘ）４０×１０－５／Ｋ以下であり、かつ（ＣＴＥｍａｘ－ＣＴＥｍｉｎ）が２５×１０－５／Ｋ超３５×１０－５／Ｋ以下であった。
　不可（０点）：（ＣＴＥｍａｘ）４０×１０－５／Ｋ超である、又は（ＣＴＥｍａｘ－ＣＴＥｍｉｎ）が３５×１０－５／Ｋ超であった。 <Evaluation of thermal expansion coefficient>
If the maximum value (CTE max ) of the coefficient of thermal expansion calculated by the above method is small and the difference (CTE max - CTE min ) between the maximum value (CTE max ) and the minimum value (CTE min ) is small, the thermal expansion coefficient is low. Since the TMA curve has a relatively linear TMA curve without a sudden rise in the rate, it has good handling properties and is thought to be less likely to cause cracks or fractures at the interface between the substrate and the sealing material during solder melting. The maximum value (CTE max ) of the coefficient of thermal expansion of the spherical cristobalite powder of Comparative Example 3 calculated by the above method is 49.7×10 −5 /K, and the difference (CTE max - CTE min ) was 38.0×10 −5 /K. Therefore, for the inorganic powder obtained in each example, the difference (CTE max - CTE min ) was calculated and evaluated using the following evaluation criteria. The results are shown in Tables 2 and 3.
(Evaluation criteria)
Excellent (3 points): (CTE max ) was 40×10 −5 /K or less, and (CTE max − CTE min ) was 15×10 −5 /K or less.
Good (2 points): (CTE max ) was 40×10 −5 /K or less, and (CTE max − CTE min ) was more than 15×10 −5 /K and 25×10 −5 /K or less.
Fair (1 point): (CTE max ) was 40×10 −5 /K or less, and (CTE max − CTE min ) exceeded 25×10 −5 /K and was 35×10 −5 /K or less.
Not acceptable (0 points): (CTE max ) exceeded 40×10 −5 /K, or (CTE max − CTE min ) exceeded 35×10 −5 /K.
＜熱膨張率の評価＞
　リフロー時や半導体デバイスの作動時に反りやクラックが発生しにくいという観点からは、球状クリストバライト粉末と同程度の熱膨張率を示すことが好ましい。比較例３の球状クリストバライト粉末の熱膨張率（１７０～２７０℃）は１５７３．９（×１０－５）であった。一方、比較例４の球状非晶質シリカ粉末及び比較例５の破砕石英粉末の熱膨張率（１７０～２７０℃）は、それぞれ、１０１２．７（×１０－５）、１１１１．７（×１０－５）であったことから、以下の評価基準で各例の無機粉末の熱膨張率（１７０～２７０℃）を評価した。結果を表２～３に示す。
（評価基準）
　優（３点）：熱膨張率（１７０～２７０℃）が１５５０（×１０－５）以上であった。
　良（２点）：熱膨張率（１７０～２７０℃）が１３５０（×１０－５）以上１５５０（×１０－５）未満であった。
　可（１点）：熱膨張率（１７０～２７０℃）が１１５０（×１０－５）以上１３５０（×１０－５）未満であった。
　不可（０点）：熱膨張率（１７０～２７０℃）が１１５０（×１０－５）未満であった。 <Evaluation of thermal expansion coefficient>
From the viewpoint of preventing warping or cracking during reflow or operation of a semiconductor device, it is preferable that the powder exhibits a coefficient of thermal expansion comparable to that of spherical cristobalite powder. The coefficient of thermal expansion (170 to 270°C) of the spherical cristobalite powder of Comparative Example 3 was 1573.9 (×10 −5 ). On the other hand, the thermal expansion coefficients (170 to 270°C) of the spherical amorphous silica powder of Comparative Example 4 and the crushed quartz powder of Comparative Example 5 are 1012.7 (×10 −5 ) and 1111.7 (×10 -5 ), the coefficient of thermal expansion (170 to 270°C) of the inorganic powder of each example was evaluated using the following evaluation criteria. The results are shown in Tables 2 and 3.
(Evaluation criteria)
Excellent (3 points): The coefficient of thermal expansion (170 to 270°C) was 1550 (×10 −5 ) or more.
Good (2 points): The coefficient of thermal expansion (170 to 270° C.) was 1350 (×10 −5 ) or more and less than 1550 (×10 −5 ).
Fair (1 point): The coefficient of thermal expansion (170 to 270°C) was 1150 (×10 −5 ) or more and less than 1350 (×10 −5 ).
Not acceptable (0 points): The coefficient of thermal expansion (170 to 270°C) was less than 1150 (×10 −5 ).
＜総合評価＞
　前述の熱膨張係数及び熱膨張率の評価結果を以下の総合評価に基づいて評価し、可以上のものを合格とした。結果を表２～３に示す。
　（総合評価）
　優：ＣＴＥｍａｘ及び熱膨張率（１７０～２７０℃）の合計点が６点。
　良：ＣＴＥｍａｘ及び熱膨張率（１７０～２７０℃）の合計点が５点。
　可：ＣＴＥｍａｘ及び熱膨張率（１７０～２７０℃）の合計点が４点（ただし、ＣＴＥｍａｘ又は熱膨張率（１７０～２７０℃）のどちらかの評価点が１点のものを除く）。
　不可：ＣＴＥｍａｘ又は熱膨張率（１７０～２７０℃）のどちらかの評価点が１点であり、かつ合計点が４点以下。 <Comprehensive evaluation>
The evaluation results of the thermal expansion coefficient and coefficient of thermal expansion described above were evaluated based on the following comprehensive evaluation, and those that were fair or better were judged as passing. The results are shown in Tables 2 and 3.
(comprehensive evaluation)
Excellent: Total score of CTE max and coefficient of thermal expansion (170-270°C) is 6 points.
Good: Total score of CTE max and coefficient of thermal expansion (170 to 270°C) is 5 points.
Acceptable: The total score for CTE max and coefficient of thermal expansion (170-270°C) is 4 points (excluding those with 1 point for either CTE max or coefficient of thermal expansion (170-270°C)).
Not acceptable: The evaluation score for either CTE max or coefficient of thermal expansion (170-270°C) is 1 point, and the total score is 4 points or less.
　なお、本実施例で使用した原料の詳細は以下のとおりである。
　炭酸カルシウム（ＣａＣＯ３）：宇部マテリアルズ（株）製、製品名「ＣＳ　３Ｎ－Ａ」。
　酸化アルミニウム（Ａｌ２Ｏ３）：日本アエロジル（株）製、製品名「Ａｌｕ－Ｃ」。
　酸化亜鉛（ＺｎＯ）：ハクスイテック（株）製、製品名「酸化亜鉛二種」。
　酸化チタン（ＴｉＯ２）：東邦チタニウム（株）製、製品名「ＨＴ２３２１」
　炭酸ストロンチウム（ＳｒＣＯ３）：堺化学工業（株）製、製品名「ＳＷ－Ｋ２０」
　チタン酸ストロンチウム（ＳｒＴｉＯ３）：共立マテリアル（株）製、製品名「ＳＴ－１Ｓ」。
　酸化マグネシウム（ＭｇＯ）：堺化学工業（株）製、製品名「ＳＭＯ－０．１」。
　アルミン酸マグネシウム（ＭｇＡｌ２Ｏ４）：タテホ化学工業（株）製、製品名「ＴＡＴＥＭＩＣ（登録商標）ＳＮ－１」。
　水酸化バリウム８水和物（Ｂａ（ＯＨ）２・８Ｈ２Ｏ）：富士フィルム和光純薬（株）製、製品名「水酸化バリウム８水和物」。
　チタン酸バリウム（ＢａＴｉＯ３）：共立マテリアル（株）製、製品名「ＢＴ－ＳＡ」。
　非晶質球状シリカ粉末：デンカ（株）製、製品名「ＦＲ－４０Ｒ」（結晶質シリカ粉末１～６、１０～１２の原料）。
　非晶質球状シリカ粉末；デンカ（株）製、製品名「ＦＢ－５Ｄ」（結晶質シリカ粉末７～９の原料）。
　破砕石英：富士フィルム和光純薬（株）製、製品名「二酸化ケイ素」、結晶化率：１００質量％、結晶相中の石英の割合：１００質量％。 The details of the raw materials used in this example are as follows.
Calcium carbonate (CaCO 3 ): Manufactured by Ube Materials Co., Ltd., product name “CS 3N-A”.
Aluminum oxide (Al 2 O 3 ): manufactured by Nippon Aerosil Co., Ltd., product name “Alu-C”.
Zinc oxide (ZnO): Manufactured by Hakusuitec Co., Ltd., product name: "Zinc oxide type 2".
Titanium oxide (TiO 2 ): manufactured by Toho Titanium Co., Ltd., product name “HT2321”
Strontium carbonate (SrCO 3 ): Manufactured by Sakai Chemical Industry Co., Ltd., product name “SW-K20”
Strontium titanate (SrTiO 3 ): manufactured by Kyoritsu Materials Co., Ltd., product name “ST-1S”.
Magnesium oxide (MgO): manufactured by Sakai Chemical Industry Co., Ltd., product name "SMO-0.1".
Magnesium aluminate (MgAl 2 O 4 ): manufactured by Tateho Chemical Industry Co., Ltd., product name “TATEMIC (registered trademark) SN-1”.
Barium hydroxide octahydrate (Ba(OH) 2.8H 2 O): manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., product name "Barium hydroxide octahydrate".
Barium titanate (BaTiO 3 ): manufactured by Kyoritsu Materials Co., Ltd., product name “BT-SA”.
Amorphous spherical silica powder: manufactured by Denka Co., Ltd., product name "FR-40R" (raw material for crystalline silica powders 1 to 6 and 10 to 12).
Amorphous spherical silica powder; manufactured by Denka Co., Ltd., product name "FB-5D" (raw material for crystalline silica powders 7 to 9).
Crushed quartz: manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., product name "silicon dioxide", crystallization rate: 100% by mass, proportion of quartz in crystal phase: 100% by mass.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　図４は実施例１の無機粉末のＴＭＡ曲線である。図４に示す通り、本実施形態の構成を満たす実施例の無機粉末は、ＴＭＡ分析において、熱膨張率の急激な立ち上がりがなく、比較例３の球状クリストバライト粉末よりも熱膨張係数が低かった。さらに、熱膨張率（１７０～２７０℃）は比較例４～５の球状非晶質シリカ粉末や破砕石英粉末よりも高く、比較例３の球状クリストバライト粉末と同程度の値を有していた。また、実施例２～８の無機粉末も、熱膨張係数が低く、かつ高熱膨張率を達成できた。一方で、半値幅が本実施形態の範囲よりも小さかった比較例１の無機粉末は、比較例３の球状クリストバライト粉末と同程度の熱膨張係数を有しており、クリストバライトのα－β相転移に伴う熱膨張挙動を制御できていなかった。また、半値幅が本実施形態の範囲よりも大きかった比較例２の無機粉末では、熱膨張係数は比較例３よりも小さかったものの、高熱膨張率を達成できなかった。以上の結果より、本実施形態に係る無機粉末及びその製造方法によれば、従来のクリストバライト粉末よりも低い熱膨張係数を有し、かつ高熱膨張率を達成できる無機粉末を提供できることが分かった。このような無機粉末を含む本実施形態に係る樹脂組成物は、封止材用フィラーとして好適に用いることができる。 FIG. 4 is a TMA curve of the inorganic powder of Example 1. As shown in FIG. 4, the inorganic powder of the example that satisfies the configuration of this embodiment did not have a rapid rise in the coefficient of thermal expansion in the TMA analysis, and had a lower coefficient of thermal expansion than the spherical cristobalite powder of Comparative Example 3. Furthermore, the coefficient of thermal expansion (170 to 270° C.) was higher than that of the spherical amorphous silica powder and crushed quartz powder of Comparative Examples 4 and 5, and had a value comparable to that of the spherical cristobalite powder of Comparative Example 3. Furthermore, the inorganic powders of Examples 2 to 8 also had low coefficients of thermal expansion and were able to achieve high coefficients of thermal expansion. On the other hand, the inorganic powder of Comparative Example 1 whose half width was smaller than the range of this embodiment had a coefficient of thermal expansion comparable to that of the spherical cristobalite powder of Comparative Example 3, and the α-β phase transition of cristobalite The thermal expansion behavior associated with this process could not be controlled. Further, in the inorganic powder of Comparative Example 2 whose half width was larger than the range of this embodiment, although the coefficient of thermal expansion was smaller than that of Comparative Example 3, a high coefficient of thermal expansion could not be achieved. From the above results, it was found that the inorganic powder and the manufacturing method thereof according to the present embodiment can provide an inorganic powder that has a lower coefficient of thermal expansion than conventional cristobalite powder and can achieve a high coefficient of thermal expansion. The resin composition according to this embodiment containing such an inorganic powder can be suitably used as a filler for a sealing material.
　上述の通り、本実施形態に係る無機粉末及びその製造方法は、従来のクリストバライト粉末よりも低い熱膨張係数を有し、かつ高熱膨張率を達成可能な無機粉末を提供できる。このような無機粉末を含む本実施形態に係る樹脂組成物は、封止材用フィラーとして好適に用いることができる。
  As described above, the inorganic powder and the method for producing the same according to the present embodiment can provide an inorganic powder that has a lower coefficient of thermal expansion than conventional cristobalite powder and can achieve a high coefficient of thermal expansion. The resin composition according to this embodiment containing such an inorganic powder can be suitably used as a filler for a sealing material.

Claims (10)

  1. 　無機粉末であって、
    　前記無機粉末は、α－β相転移開始温度が異なる少なくとも２種類の結晶質シリカ粉末を含み、前記少なくとも２種類の結晶質シリカ粉末は、いずれも、結晶相及び非晶質相の合計量（１００質量％）に対するα－クリストバライト相の割合が３０質量％以上であり、
    　前記無機粉末のα－クリストバライト相の（１０１面）のＸ線回折ピークの半値幅（ＦＷＨＭ）が、０．１２０°～０．３００°である、無機粉末。     An inorganic powder,
    The inorganic powder includes at least two types of crystalline silica powders having different α-β phase transition initiation temperatures, and the at least two types of crystalline silica powders each have a total amount of crystalline phase and amorphous phase ( The ratio of α-cristobalite phase to 100% by mass) is 30% by mass or more,
    The inorganic powder, wherein the half width (FWHM) of the (101 plane) X-ray diffraction peak of the α-cristobalite phase of the inorganic powder is 0.120° to 0.300°.
  2. 　前記無機粉末の平均円形度が０．８０以上である、請求項１に記載の無機粉末。 The inorganic powder according to claim 1, wherein the inorganic powder has an average circularity of 0.80 or more.
  3. 　前記無機粉末の平均粒子径（Ｄ５０）が１００μｍ以下である、請求項１または２に記載の無機粉末。 The inorganic powder according to claim 1 or 2, wherein the inorganic powder has an average particle diameter (D50) of 100 μm or less.
  4. 　α－β相転移開始温度が最も低い結晶質シリカ粉末（Ａ）のα－β相転移開始温度（ＴＡ）と、α－β相転移開始温度が最も高い結晶質シリカ粉末（Ｂ）のα－β相転移開始温度（ＴＢ）との差（ＴＢ－ＴＡ）が、９０℃以下である、請求項１または２に記載の無機粉末。 α-β phase transition onset temperature (TA) of crystalline silica powder (A) with the lowest α-β phase transition onset temperature and α-β phase transition onset temperature of crystalline silica powder (B) with the highest α-β phase transition onset temperature The inorganic powder according to claim 1 or 2, wherein the difference (TB-TA) from the β phase transition initiation temperature (TB) is 90° C. or less.
  5. 　前記α－β相転移開始温度（ＴＡ）が１７０～２５０℃であり、前記α－β相転移開始温度（ＴＢ）が２００～２８０℃である、請求項４に記載の無機粉末。 The inorganic powder according to claim 4, wherein the α-β phase transition onset temperature (TA) is 170 to 250°C, and the α-β phase transition onset temperature (TB) is 200 to 280°C.
  6. 　前記無機粉末のＴＭＡ曲線から算出される熱膨張係数の最大値（ＣＴＥｍａｘ）が、４０×１０－５／Ｋ以下である、請求項１または２に記載の無機粉末。 The inorganic powder according to claim 1 or 2, wherein the maximum value of the coefficient of thermal expansion (CTE max ) calculated from the TMA curve of the inorganic powder is 40×10 −5 /K or less.
  7. 　請求項１または２に記載の無機粉末と、熱可塑性樹脂及び熱硬化性樹脂から選択される少なくとも１つの樹脂とを含む、樹脂組成物。 A resin composition comprising the inorganic powder according to claim 1 or 2 and at least one resin selected from thermoplastic resins and thermosetting resins.
  8. 　封止材用である、請求項７に記載の樹脂組成物。 The resin composition according to claim 7, which is used as a sealant.
  9. 　請求項１または２に記載の無機粉末の製造方法であって、
    　α－β相転移開始温度が異なる少なくとも２種類の結晶質シリカ粉末を混合することを含み、
    　前記少なくとも２種類の結晶質シリカ粉末は、いずれも、結晶相及び非晶質相の合計量（１００質量％）に対するα－クリストバライト相の割合が３０質量％以上である、無機粉末の製造方法。     A method for producing an inorganic powder according to claim 1 or 2, comprising:
    Mixing at least two types of crystalline silica powders having different α-β phase transition initiation temperatures,
    A method for producing an inorganic powder, wherein the at least two types of crystalline silica powder each have an α-cristobalite phase of 30% by mass or more relative to the total amount (100% by mass) of the crystalline phase and the amorphous phase.
  10. 　前記少なくとも２種類の結晶質シリカ粉末が、１７０～２８０℃の範囲にα－β相転移開始温度を有する、請求項９に記載の無機粉末の製造方法。
          The method for producing an inorganic powder according to claim 9, wherein the at least two types of crystalline silica powders have an α-β phase transition initiation temperature in a range of 170 to 280°C.
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WO2016031823A1 (en) * 2014-08-25 2016-03-03 新日鉄住金マテリアルズ株式会社 Spherical crystalline silica particles and method for producing same
WO2020241902A1 (en) * 2019-05-31 2020-12-03 日鉄ケミカル＆マテリアル株式会社 Spherical crystalline silica particles, spherical silica particle mixture, and composite material

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Publication number Priority date Publication date Assignee Title
WO2016031823A1 (en) * 2014-08-25 2016-03-03 新日鉄住金マテリアルズ株式会社 Spherical crystalline silica particles and method for producing same
WO2020241902A1 (en) * 2019-05-31 2020-12-03 日鉄ケミカル＆マテリアル株式会社 Spherical crystalline silica particles, spherical silica particle mixture, and composite material

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