Silicon carbide particles, method for producing silicon carbide particles

Abstract

To provide a silicon carbide particle suitable for use as a material for catalyst carriers and parts for semiconductor manufacturing apparatuses (wafer forks, chucks, push-up pins, etc.).SOLUTION: A silicon carbide particle made of α-SiC secondary particles that have, based on wight, an Al content of 150 ppm or less, a Y content of 150 ppm or less, a B content of 150 ppm or less, a content of C not bound to Si of 0.15% or less, a Ca content of 50 ppm or less, a Cr content of 50 ppm or less, an Fe content of 50 ppm or less, a Ni content of 50 ppm or less, a ratio of D90% particle size to D50% particle size (D90 / D50) of 2.5 or less, and a specific surface area of 0.90 m2 / g or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to silicon carbide particles and a method for producing the same. [Background technology]

[0002] Silicon carbide particles are highly hard, have excellent wear resistance and sliding properties, high heat resistance, and are chemically stable. When silicon carbide particles are used as catalyst supports or as materials for semiconductor manufacturing equipment components (wafer forks, chucks, push-up pins, etc.), highly pure, porous silicon carbide particles with excellent fluidity are desired. Furthermore, silicon carbide particles are used as reinforcing materials for metal matrix composites (MMCs) that form semiconductor manufacturing equipment components. However, there are no conventional porous silicon carbide particles that are suitable for the above applications, possessing high purity and excellent fluidity.

[0003] Patent Document 1 describes a material with an average particle size of 5 to 60 μm and an internal pore volume of 0.02 cm³ with a pore diameter of 1 μm or less. 3 Less than or equal to / g, and with a specific surface area of ​​1 m² 2 Spherical α-type silicon carbide with an average (short axis / long axis) aspect ratio of 0.65 or higher at a concentration of less than / g is listed. Furthermore, Patent Document 1 describes a method for producing spherical α-type silicon carbide, which includes the steps of spray-drying a slurry of raw silicon carbide, which is an α-type crystal with an average particle size of 1 μm or less, to obtain porous, spherical particles, and sintering the obtained porous, spherical particles. In the production method of the example, spray-drying is performed by adding a dispersant and a sintering aid to the slurry.

[0004] Patent Document 2 describes how secondary particles obtained by sintering only silicon carbide powder (primary particle size D50: 0.26 μm) without using sintering aids or binders have a D50 of 43.2 μm and a specific surface area of ​​0.98 m². 2 It was noted that the value was / g. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2013-95637 [Patent Document 2] WO2020 / 194974 pamphlet [Overview of the project] [Problems that the invention aims to solve]

[0006] The object of the present invention is to provide silicon carbide particles that can be suitably used as catalyst supports or as materials for semiconductor manufacturing equipment components (wafer forks, chucks, push-up pins, etc.). [Means for solving the problem]

[0007] To solve the above problems, one aspect of the present invention comprises α-SiC secondary particles, wherein, by mass ratio, the Al content is 150 ppm or less, the Y content is 150 ppm or less, the B content is 150 ppm or less, the C content not bonded to Si is 0.15% or less, the Ca content is 50 ppm or less, the Cr content is 50 ppm or less, the Fe content is 50 ppm or less, and the Ni content is 50 ppm or less, the ratio of the D90% particle diameter to the D50% particle diameter (D90 / D50) is 2.5 or less, and the specific surface area is 0.90 m². 2 This provides silicon carbide particles that are less than or equal to / g. [Effects of the Invention]

[0008] According to the present invention, silicon carbide particles that can be suitably used as catalyst supports or components for semiconductor manufacturing equipment (wafer forks, chucks, push-up pins, etc.) can be provided. [Brief explanation of the drawing]

[0009] [Figure 1] This is an SEM image of the surface of silicon carbide particles from Example 1. [Figure 2] This is an SEM image of the surface of silicon carbide particles from Example 2. [Figure 3]SEM image of the surface of silicon carbide particles of Example 3. [Figure 4] SEM image of the surface of silicon carbide particles of Example 4. [Figure 5] SEM image showing the state after granulation of Comparative Example 1.

Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the embodiments shown below. In the embodiments shown below, technically preferable limitations are made to carry out the present invention, but this limitation is not an essential requirement of the present invention.

[0011] 〔Configuration〕 The silicon carbide particles of this embodiment are composed of secondary particles of α-SiC, and in terms of mass ratio, the content of Al is 150 ppm or less, the content of Y is 150 ppm or less, the content of B is 150 ppm or less, the content of C not bonded to Si is 0.15% or less, the content of Ca is 50 ppm or less, the content of Cr is 50 ppm or less, the content of Fe is 50 ppm or less, and the content of Ni is 50 ppm or less, and the ratio of the D90% particle diameter to the D50% particle diameter (D90 / D50) is 2.5 or less, and the specific surface area is 0.90 m 2 / g or less.

[0012] In the silicon carbide particles of this embodiment, the ratio of the D90% particle diameter to the D50% particle diameter (D90 / D50) is preferably 1.1 or more and 2.5 or less. When "D90 / D50" is 2.5 or less, granule collapse (a part of the primary particles forming the secondary particles falls off) does not occur and the granule shape can be maintained, so that a decrease in fluidity can be suppressed. Also, when "D90 / D50" is 1.1 or more, the packing property is improved from the viewpoint of the densest packing. Note that D50 and D90 are measured by, for example, a particle size distribution measuring device based on the laser diffraction / scattering method, and respectively mean the cumulative 50% particle diameter and the cumulative 90% particle diameter from the small particle size side in the volume-based integrated particle diameter distribution of the silicon carbide secondary particles.

[0013] In the silicon carbide particles of the present embodiment, the specific surface area is preferably 0.10 m 2 / g or more and 0.90 m 2 / g or less. When the specific surface area is 0.90 m 2 / g or less, it becomes easier to cope with changes over time in a high-temperature environment. When it is 0.10 m 2 / g or more, the voids in the granules become larger, making it suitable as a material for catalyst carriers and parts for semiconductor manufacturing equipment. Further, the specific surface area is more preferably 0.20 m 2 / g or more and 0.85 m 2 / g or less, and particularly preferably 0.30 m 2 / g or more and 0.80 m 2 / g or less. The specific surface area is measured, for example, by the method described in the following examples.

[0014] In the silicon carbide particles of the present embodiment, the SiO2 content is preferably 0.10 mass% or less. When the SiO2 content is 0.10 mass% or less, it is easy to obtain the required purity. Further, the SiO2 content is more preferably 0.05 mass% or less, and particularly preferably 0.03 mass% or less. The SiO2 content is measured, for example, by the method described in the following examples. In the silicon carbide particles of the present embodiment, the granule strength measured by a micro-compression test is preferably 25 MPa or more. When the granule strength is 25 MPa or more, it is easy to suppress granule collapse. Further, the granule strength is more preferably 30 MPa or more, and particularly preferably 35 MPa or more. Also, the upper limit of the granule strength is not particularly limited, but can be 200 MPa or less.

[0015] The silicon carbide particles of this embodiment are secondary particles composed of multiple α-SiC primary particles. The ratio of the D50% particle diameter of the secondary particles (secondary D50) to the D50% particle diameter of the primary particles (primary D50) (secondary D50 / primary D50) is preferably 150 or less. When "secondary D50 / primary D50" is 150 or less, the necessary porosity is easily obtained. Furthermore, "secondary D50 / primary D50" is more preferably 5 or more and 150 or less, and particularly preferably 6 or more and 100 or less. The primary particle diameter and secondary particle diameter can be measured, for example, by the method described in the following examples. A primary particle refers to a single particle, and a secondary particle refers to a particle formed by the aggregation and bonding of multiple primary particles.

[0016] The silicon carbide particles of this embodiment can be manufactured by using primary α-SiC particles having a D50% particle diameter of 0.5 μm or more and a ratio of the D50% particle diameter to the D94% particle diameter (D50 / D94) of 3 or more, granulating the primary particles without using sintering aids, binders, or dispersants to obtain granules, and then sintering the obtained granules. When α-SiC primary particles with a D50% particle diameter of 0.5 μm or more are used, voids of appropriate size tend to form easily. When α-SiC primary particles with a D50% particle diameter of 3.2 μm or less are used, granular shape tends to be maintained without granular breakdown. Furthermore, the D50% particle diameter of the α-SiC primary particles used is more preferably between 1.0 μm and 3.0 μm, and particularly preferably between 2.0 μm and 2.8 μm.

[0017] Furthermore, by using α-SiC primary particles with a "D50 / D94" ratio of 3 or higher, granulation becomes easier without the use of sintering aids, binders, dispersants, etc. By not using at least one of the sintering aids, binders, and dispersants, the purity of the resulting secondary particles can be increased. Moreover, the "D50 / D94" ratio of the α-SiC primary particles used is more preferably between 4 and 50, and particularly preferably between 5 and 10.

[0018] [Action, effect] The silicon carbide particles of this embodiment consist of α-SiC secondary particles, with a mass ratio of Al content of 150 ppm or less, Y content of 150 ppm or less, B content of 150 ppm or less, unbonded C content of 0.15% or less, Ca content of 50 ppm or less, Cr content of 50 ppm or less, Fe content of 50 ppm or less, and Ni content of 50 ppm or less. The ratio of D90% particle diameter to D50% particle diameter (D90 / D50) is 2.5 or less, and the specific surface area is 0.90 m². 2 It is less than / g. Furthermore, the silicon carbide particles in this embodiment are obtained by using α-SiC primary particles with a D50% particle diameter of 0.5 μm or more and a ratio of the D50% particle diameter to the D94% particle diameter (D50 / D94) of 3 or more, granulating these primary particles without using sintering aids, binders, or dispersants to obtain granules, and then sintering the obtained granules.

[0019] The silicon carbide particles of this embodiment have a specific surface area of ​​0.90 m². 2 Because it is composed of secondary α-SiC particles with a weight of less than / g, when used as a reinforcing material for MMC, changes over time during heating when manufacturing MMC material are suppressed, and when used as a catalyst support for high-temperature environments, changes over time during use are suppressed. The silicon carbide particles in this embodiment are obtained by the method described above, and by setting the D50% particle diameter of the α-SiC primary particles used to 0.5 μm or more, they have good voids for use as a reinforcing material and catalyst support for MMC.

[0020] Specifically, in the case of silicon carbide particles obtained by the above method, when metal is impregnated into the silicon carbide particles to manufacture MMC material, the metal impregnation becomes easier. In other words, the silicon carbide particles obtained by the above method have voids that are not too fine, which are suitable for metal impregnation. Furthermore, in the case of silicon carbide particles obtained by the above method, gas flowability is improved when the silicon carbide particles are used as a catalyst support, thereby enhancing the activity of the catalyst. In other words, the silicon carbide particles obtained by the above method have voids that are not too fine, which is suitable for improving gas flowability. Therefore, the silicon carbide particles of this embodiment can be suitably used as a catalyst support or a material for semiconductor manufacturing equipment components (wafer forks, chucks, push-up pins, etc.). [Examples]

[0021] The present invention will be described in more detail below with reference to examples and comparative examples.

[0022] [Manufacturing of silicon carbide secondary particles] <Preparation of α-SiC primary particles> As primary particles of α-SiC, we prepared "GC#6000 (product name)", "GC#8000 (product name)", and "GC#10000 (product name)" manufactured by Fujimi Incorporated Co., Ltd. The particle size distribution of each primary particle was measured using the "MT-3300" laser diffraction / scattering particle size distribution analyzer manufactured by Microtrac-Bell Co., Ltd., and the D3%, D50%, and D94% particle sizes were determined. The D3%, D50%, and D94% particle sizes determined here are the particle sizes at which the cumulative frequency from the larger diameter side accounts for 3%, 50%, and 94% in the volume-based cumulative particle size distribution. Furthermore, "GC#6000 (product name)" and "GC#10000 (product name)" were mixed in a mass ratio of GC#6000:GC#10000 = 76.92:23.08. The particle size distribution of the mixed primary particles was measured using the same method as above, and the D3% particle size, D50% particle size, and D94% particle size were examined.

[0023] <Example 1> First, the mixed α-SiC primary particles were used as raw material powder and dispersed in a solvent such as water to obtain a slurry. This slurry was supplied to a disc-type spray dryer for granulation, and granules consisting only of α-SiC primary particles were obtained. Next, the obtained granules were sintered using a resistance-heating sintering furnace "FVS-R" manufactured by Fuji Denpa Kogyo Co., Ltd. to produce sintered granules (secondary particles). The operating conditions of the sintering furnace were argon atmosphere, sintering temperature of 1850°C, and sintering time of 4 hours. The obtained sintered granules were crushed using a centrifugal mill manufactured by Verder Scientific, Inc. The rotation speed of the centrifugal mill was 12,000 rpm. After that, the particle size was adjusted using a sieve with a mesh size of 106 μm. In this way, the silicon carbide secondary particles of Example 1 were obtained.

[0024] <Example 2> Silicon carbide secondary particles of Example 2 were obtained by the same method as in Example 1, except that the granules consisting only of the above-mentioned mixed α-SiC primary particles were sintered at a sintering temperature of 1950°C. <Example 3> The silicon carbide secondary particles of Example 3 were obtained using the same method as in Example 1, except that granules were obtained using only "GC#8000 (product name)" as the raw material powder, and the obtained granules were sintered at a sintering temperature of 1950°C. <Example 4> The silicon carbide secondary particles of Example 4 were obtained using the same method as in Example 1, except that granules were obtained using only "GC#10000 (product name)" as the raw material powder, and the obtained granules were sintered at a sintering temperature of 1950°C.

[0025] <Comparative Example 1> We attempted to obtain granules using only "GC#6000 (product name)" as the raw material powder in the same manner as in Example 1, but we were unable to obtain granules. <Comparative Example 2> For Comparative Example 2, we prepared "GC#40000 (product name)" manufactured by Fujimi Incorporated as the primary α-SiC particles. The D50% particle size of these α-SiC primary particles is 0.26 μm. Comparative Example 2 silicon carbide secondary particles were obtained using the same method as in Example 1, except that only "GC#40000 (product name)" was used as the raw material powder to obtain granules, and the obtained granules were sintered at a sintering temperature of 1900°C.

[0026] [Measurement of Physical Properties of Silicon Carbide Secondary Particles] <Particle Size> The particle sizes (D50% particle size, D90% particle size) of each of the obtained silicon carbide secondary particles were measured using a laser diffraction / scattering particle size distribution measuring device LA-300 manufactured by Horiba, Ltd. For Comparative Example 2, only the D50% particle size was measured. The D50% particle size and D90% particle size examined here are the particle sizes at which the integrated frequency from the small-diameter side is 50% and 90% in the volume-based integrated particle size distribution.

[0027] <Specific Surface Area> The specific surface area of each of the obtained silicon carbide secondary particles was measured using a fully automatic BET specific surface area measuring device "Macsorb (registered trademark)" manufactured by Mountech Co., Ltd.

[0028] <Granule Strength> The granule strength of each of the obtained silicon carbide secondary particles was measured using a micro compression tester "MCT-200" manufactured by Shimadzu Corporation. The method of the micro compression test is as follows. First, each silicon carbide secondary particle was observed with a microscope attached to the micro compression tester, and 5 - 10 particles with dimensions of about each measured value of the D50% particle size were randomly selected in the observation field of view. Next, the granule strength of each selected particle was measured with the micro compression tester, and the average value of those measured values was taken as the granule strength of the filler. The measurement conditions were a load rate of 12.96 mN / second and a load holding time of 1 second.

[0029] <SEM Image> SEM images of the surfaces of each of the obtained silicon carbide secondary particles were taken at 200 times magnification. The images are shown in FIG. 1 for Example 1, FIG. 2 for Example 2, FIG. 3 for Example 3, and FIG. 4 for Example 4. For Comparative Example 1, an SEM image taken at 200 times magnification of the state after the granulation process is shown in FIG. 5.

[0030] [Measurement of Impurity Content] The impurities in each of the obtained silicon carbide secondary particles were measured using an inductively coupled plasma emission spectrometer "ICPS-8100" manufactured by Shimadzu Corporation. The SiO2 content was measured in accordance with "JIS R 1616". The content of carbon not bonded to Si was measured in accordance with "JIS R 6124".

[0031] Table 1 shows the raw materials and firing temperatures for each silicon carbide secondary particle, and Table 2 shows the results of the physical property measurements. Note that no granules were obtained in Comparative Example 1, so Table 2 shows the results for Examples 1-4 and Comparative Example 2.

[0032] [Table 1]

[0033] [Table 2]

[0034] As shown in Table 1, the α-SiC primary particles used as raw materials in Examples 1 to 4 satisfy the condition that "the D50% particle diameter is 0.5 μm or larger, and the ratio of the D50% particle diameter to the D94% particle diameter (D50 / D94) is 3 or larger," but the α-SiC primary particles used as raw materials in Comparative Examples 1 and 2 do not satisfy this condition. Furthermore, the results in Table 2 show that by using α-SiC primary particles satisfying the above configuration as raw materials and performing granulation and sintering of α-SiC primary particles, silicon carbide particles of Examples 1 to 4 that satisfy all of the following conditions 1 to 6 can be obtained.

[0035] (Condition 1) In terms of mass ratio, the Al content is 150 ppm or less, the Y content is 150 ppm or less, the B content is 150 ppm or less, the C content not bonded to Si is 0.15% or less, the Ca content is 50 ppm or less, the Cr content is 50 ppm or less, the Fe content is 50 ppm or less, and the Ni content is 50 ppm or less. (Condition 2) The ratio of the D90% particle size to the D50% particle size (D90 / D50) is 2.5 or less. (Condition 3) Specific surface area is 0.90 m² 2 It is less than / g. (Condition 4) The SiO2 content is 0.10% by mass or less. (Condition 5) The granular strength measured by micro-compression testing is 25 MPa or higher. (Condition 6) The ratio of the D50% particle diameter of secondary particles (secondary D50) to the D50% particle diameter of primary particles (primary D50) (secondary D50 / primary D50) is 150 or less.

[0036] Furthermore, the silicon carbide particles of Examples 1-4 had a ratio of the D90% particle diameter to the D50% particle diameter (D90 / D50) of 1.48 to 2.17, and a specific surface area of ​​0.58 m². 2 / g or more 0.85m 2 The saturation is less than or equal to / g, the SiO2 content is 0.02% by mass, the granular strength is between 25.75 MPa and 68.41 MPa, and the "secondary D50 / primary D50" ratio is between 7.04 and 65.55 MPa. Furthermore, since the silicon carbide particles of Examples 1 to 4 do not contain sintering aids, binders, or dispersants, they have high α-SiC purity and can be suitably used in applications where the inclusion of impurities is a concern. Furthermore, because the silicon carbide particles of Examples 1 to 4 possess the above-mentioned physical properties, they are porous particles with high purity and excellent fluidity, making them suitable for use as catalyst supports or as materials for semiconductor manufacturing equipment components (wafer forks, chucks, push-up pins, etc.).

Claims

1. It consists of sintered granules of α-SiC, In terms of mass ratio, the Al content is 150 ppm or less, the Y content is 150 ppm or less, the B content is 150 ppm or less, the C content not bonded to Si is 0.15% or less, the Ca content is 50 ppm or less, the Cr content is 50 ppm or less, the Fe content is 50 ppm or less, and the Ni content is 50 ppm or less. The ratio of the D90% particle size to the D50% particle size (D90 / D50) is 2.5 or less. Specific surface area is 0.90 m² 2 / g or less, Silicon carbide particles with a granular strength of 25 MPa or higher, as measured by microcompression testing.

2. SiO 2 The silicon carbide particles according to claim 1, wherein the content of is 0.10% by mass or less.

3. Using α-SiC primary particles with a D50% particle diameter of 0.5 μm or more and a ratio of the D50% particle diameter to the D94% particle diameter (D50 / D94) of 3 or more, A method for producing silicon carbide particles according to claim 1 or 2, comprising granulating the primary particles to obtain a granule without using a sintering aid, binder, and dispersant, and sintering the obtained granule.

Images