Composite sintered body, bonded body, semiconductor manufacturing device component, and method for manufacturing composite sintered body

Abstract

The present invention relates to a composite sintered body, a bonded body, a member for a semiconductor manufacturing apparatus, and a method for manufacturing a composite sintered body, and provides a composite sintered body which is composed of a different configuration from the past, has a difference in linear thermal expansion coefficient from aluminum nitride which is equivalent to or smaller than the past, and is dense. The composite sintered body is composed of silicon carbide, tungsten silicide, and tungsten carbide, contains 14.4 wt% or more and 48.6 wt% or less of silicon carbide, and has an open porosity of 1% or less.

Description

Technical Field

[0001] This invention relates to sintered composite materials. Background Technology

[0002] For electrostatic chucks used in semiconductor processes operating at high temperatures, a cooling plate is incorporated for heat dissipation. For example, when the material of the electrostatic chuck is alumina, a dense sintered body made of a composite material of silicon carbide, titanium silicide, titanium silicon carbide, and titanium carbide is known as a preferred material for the cooling plate (see, for example, Patent Document 1). This composite sintered body is characterized by a small difference in linear thermal expansion coefficient with alumina, high density, and high strength.

[0003] Furthermore, it is known that a dense sintered body of a composite material formed of silicon carbide, titanium silicon carbide, and titanium carbide is preferred as the constituent material of the cooling plate when aluminum nitride is the material of the electrostatic chuck (see, for example, Patent Document 2). This composite sintered body has the characteristics of having a small difference in linear thermal expansion coefficient with aluminum nitride, being dense, and having high strength.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2014-198662

[0007] Patent Document 2: Japanese Patent Application Publication No. 2014-208567 Summary of the Invention

[0008] Aluminum nitride has a linear thermal expansion coefficient of 5.1 ppm / K at 40°C to 570°C, while the composite material disclosed in Patent Document 2 has a preferred linear thermal expansion coefficient of 5.4 ppm / K to 6.0 ppm / K at 40°C to 570°C. In the Ti-Si-C composite sintered body disclosed in Patent Document 2, achieving a linear thermal expansion coefficient of 5.1 ppm / K requires increasing the amount of silicon carbide. In this case, the density of the composite sintered body decreases, making it unsuitable for use as a cooling plate in an electrostatic chuck.

[0009] The present invention was made in view of the above-mentioned problems, and its object is to provide a dense composite sintered body composed of a different constituent phase than the conventional one, having a linear thermal expansion coefficient difference with aluminum nitride that is equal to or smaller than that of the conventional one.

[0010] To address the aforementioned issues, the first aspect of the present invention is a composite sintered body, characterized in that it is composed of silicon carbide, tungsten silicide, and tungsten carbide, containing 14.4 wt% to 48.6 wt% of silicon carbide, and having an open porosity of 1% or less.

[0011] The second aspect of the present invention is based on the composite material sintered body involved in the first aspect, characterized in that the difference between the coefficient of thermal expansion of the composite material sintered body at 40℃~550℃ and the coefficient of thermal expansion of aluminum nitride at 40℃~550℃ is less than 0.5ppm / K.

[0012] The third aspect of the present invention is based on the composite sintered body involved in the second aspect, characterized in that the open porosity is less than 0.1%.

[0013] The fourth aspect of the present invention is based on the composite sintered body involved in any one of the first to third aspects, characterized in that the surface of each crystalline particle of silicon carbide is covered by at least one of tungsten silicide or tungsten carbide, thereby crystalline particles of at least one of tungsten silicide or tungsten carbide are present in the gaps between the crystalline particles of silicon carbide.

[0014] The fifth aspect of the present invention is based on the composite material sintered body involved in any one of the first to fourth aspects, characterized in that the content of tungsten silicide is greater than the content of silicon carbide.

[0015] The sixth aspect of the present invention is based on the composite sintered body involved in any one of the first to fifth aspects, characterized in that the 4-point bending strength is 200 MPa or more.

[0016] The seventh aspect of the present invention is based on the composite sintered body involved in the sixth aspect, characterized in that the 4-point bending strength is above 350 MPa.

[0017] The eighth aspect of the present invention is based on the composite sintered body involved in any one of the first to seventh aspects, characterized in that the thermal conductivity is 90 W / m·K or higher.

[0018] The ninth aspect of the present invention, based on the composite sintered body involved in any of the first to eighth aspects, is characterized in that its fracture toughness value is 6.0 MPa·m. 1 / 2 ~8.8MPa·m 1 / 2 .

[0019] The tenth aspect of the present invention is based on the composite sintered body involved in any one of the first to ninth aspects, characterized in that the Young's modulus is 273 GPa to 594 GPa.

[0020] The eleventh aspect of the present invention is based on the composite sintered body involved in the tenth aspect, characterized in that the Young's modulus is 460 GPa to 594 GPa.

[0021] The twelfth aspect of the present invention is a joint body formed by joining a first component and a second component. The joint body is characterized in that the first component is formed of a composite sintered body composed of silicon carbide, tungsten silicide, and tungsten carbide, containing 14.4 wt% and 48.6 wt% of silicon carbide and having an open porosity of 1% or less, and the second component is formed of aluminum nitride.

[0022] The thirteenth aspect of the present invention is based on the joint involved in the twelfth aspect, characterized in that the difference between the coefficient of thermal expansion of the first component at 40°C to 550°C and the coefficient of thermal expansion of the second component at 40°C to 550°C is less than 0.5 ppm / K.

[0023] The fourteenth aspect of the present invention is based on the joint involved in the thirteenth aspect, characterized in that the porosity of the first component is less than 0.1%.

[0024] The fifteenth aspect of the present invention is based on the joint body involved in any one of the twelfth to fourteenth aspects, characterized in that the first component and the second component are metal-jointed.

[0025] The sixteenth aspect of the present invention is a component for a semiconductor manufacturing apparatus, comprising a bonding body formed by joining a first component and a second component. The component for the semiconductor manufacturing apparatus is characterized in that the first component is a cooling component for cooling the second component, and is formed of a composite sintered body composed of silicon carbide, tungsten silicide, and tungsten carbide, containing 14.4 wt% to 48.6 wt% of silicon carbide and having an open porosity of 1% or less, and the second component is formed of aluminum nitride.

[0026] The seventeenth aspect of the present invention is based on the component for a semiconductor manufacturing apparatus involved in the sixteenth aspect, characterized in that the difference between the coefficient of thermal expansion of the first component at 40°C to 550°C and the coefficient of thermal expansion of the second component at 40°C to 550°C is less than 0.5 ppm / K.

[0027] The eighteenth aspect of the present invention is based on the component for a semiconductor manufacturing apparatus involved in the seventeenth aspect, characterized in that the porosity of the first component is 0.1% or less.

[0028] The nineteenth aspect of the present invention is based on the semiconductor manufacturing apparatus component involved in any one of the sixteenth and seventeenth aspects, characterized in that the first component and the second component are metal-bonded together.

[0029] The twentieth aspect of the present invention is a method for manufacturing a composite sintered body, characterized by comprising the following steps: a mixing step, in which SiC powder, WSi2 powder, and WC powder or W powder are mixed to obtain a powder mixture; a molding step, in which the powder mixture is molded into a predetermined shape to obtain a molded body; and a firing step, in which the molded body is hot-pressed and fired under an inactive atmosphere. In the mixing step, 5.7wt% to 27.7wt% of SiC powder, 12.5wt% to 55.3wt% of WSi2 powder, and 49.5wt% to 81.3wt% of WC powder or 17.0wt% to 55.7wt% of W powder are mixed in a total weight ratio of 100wt%. In the firing step, the maximum temperature is set to 1700℃ to 1850℃, and the pressing pressure is set to 225 kgf / cm². 2 ~300kgf / cm 2 .

[0030] The twenty-first aspect of the present invention is based on the method for manufacturing composite sintered bodies involved in the twenty aspect, characterized in that, in the mixing process, 5.7wt% to 13.1wt% of SiC powder, 12.5wt% to 39.1wt% of WSi2 powder, and 49.5wt% to 81.3wt% of WC powder are mixed in a total weight ratio of 100wt%.

[0031] Invention Effects

[0032] According to the first to eleventh, twentieth and twenty-first embodiments of the present invention, a dense composite sintered body that is not prone to delamination even when bonded to aluminum nitride and used under thermal cycling is obtained.

[0033] Furthermore, according to the twelfth to nineteenth embodiments of the present invention, since component peeling is not easily caused even when the bonding body is used under thermal cycling, the service life of components for semiconductor manufacturing apparatuses equipped with the bonding body can be improved. Attached Figure Description

[0034] Figure 1 This is an example of a cross-sectional SEM image of a composite sintered body.

[0035] Figure 2 This is a graph showing the relationship between the silicon carbide content and the open porosity in the composite sintered body.

[0036] Figure 3 This is an example of the temperature and pressure curves during hot pressing. Detailed Implementation

[0037] <Sintered Composite Materials>

[0038] The composite sintered body involved in this embodiment is a composite sintered body containing silicon carbide (SiC), tungsten silicide, and tungsten carbide (WC) as crystalline phases. In the composite sintered body involved in this embodiment, when the total weight ratio of these crystalline phases is set to 100 wt%, it contains 14.4 wt% or more and 48.6 wt% or less of silicon carbide (SiC). Preferably, the content of tungsten silicide is greater than the content of silicon carbide. Specifically, the tungsten silicide is WSi2 or W5Si3.

[0039] The composite sintered body involved in this embodiment contains SiC, tungsten silicide, and tungsten carbide as crystalline phases, which was confirmed by X-ray diffraction measurement of the powder obtained by pulverizing the sintered body. In addition, the content of each substance is a value determined based on the diffraction peaks of the X-ray diffraction measurement curve (simplified quantitative value).

[0040] Furthermore, the composite sintered body involved in this embodiment is a dense material with an open porosity of 1% or less (dense composite sintered body). It should be noted that the open porosity is a value obtained by measuring using the Archimedes method with pure water as the medium.

[0041] More specifically, in the composite sintered body according to this embodiment, the surface of each silicon carbide crystalline particle is covered by at least one of tungsten silicide or tungsten carbide. Accordingly, tungsten silicide or tungsten carbide crystalline particles are present in the gaps between the silicon carbide crystalline particles.

[0042] Figure 1 This is an example of a cross-sectional SEM image of a composite sintered body involved in this embodiment. Figure 1 In the image, images of the four crystalline phases SiC, WSi2, WC, and W5Si3 are shown in order of brightness from low to high (from dark to bright). More specifically, it is confirmed that the generally black SiC crystal particles are separated from each other, while the WSi2, WC, and W5Si3 crystal particles completely cover the surrounding area of ​​each crystal particle without gaps.

[0043] In sintered bodies with a high silicon carbide content and high-frequency dispersion of silicon carbide particles, numerous pores may form between the particles. However, in the case of the composite sintered body according to this embodiment, the surface of the silicon carbide particles is covered by particles of other crystalline phases, thus almost no such pores are formed. Accordingly, the composite sintered body according to this embodiment is dense and has high strength.

[0044] Preferably, the open porosity of the composite sintered body according to this embodiment is 0.1% or less. The composite sintered body that meets this open porosity has excellent density and extremely high strength.

[0045] Figure 2 This is a graph showing the relationship between silicon carbide content and open porosity in various composite sintered bodies produced under different manufacturing conditions. Specifically, the maximum temperature and pressing pressure conditions during hot pressing, as described later, are different. Figure 2 In the figure, the data are plotted in relation to the highest temperature during hot pressing. Figure 2 The following trend was observed: the higher the silicon carbide content in the composite sintered body, the greater the open porosity. Specifically, it was found that when the silicon carbide content is approximately 50 wt% or less, composite sintered bodies with an open porosity of less than 1% can be produced by carefully setting the manufacturing conditions. Furthermore, it was also found that when the silicon carbide content is approximately 30 wt% or less, composite sintered bodies with an open porosity of less than 0.1% can be produced. On the other hand, when the silicon carbide content exceeds 50 wt%, it is difficult to obtain composite sintered bodies with a low open porosity, and therefore this is not preferred.

[0046] The linear thermal expansion coefficient of the composite sintered body involved in this embodiment is similar to that of aluminum nitride (AlN). It should be noted that, hereinafter, the linear thermal expansion coefficient will be simply referred to as the coefficient of thermal expansion.

[0047] Specifically, the difference between the coefficient of thermal expansion of the composite sintered body involved in this embodiment at 40°C to 550°C and the average coefficient of thermal expansion of aluminum nitride at 40°C to 550°C (5.1 ppm / K) is less than 0.5 ppm / K. More specifically, the coefficient of thermal expansion of the composite sintered body involved in this embodiment at 40°C to 550°C is 4.6 ppm / K to 5.6 ppm / K, preferably 4.8 to 5.3 ppm / K.

[0048] Furthermore, the composite sintered body according to this embodiment exhibits excellent thermal conductivity. Its thermal conductivity is 90 W / m·K or higher, preferably 100 W / m·K or higher.

[0049] The composite sintered body involved in this embodiment also exhibits excellent strength. Specifically, the four-point flexural strength is 200 MPa or more, preferably 350 MPa or more, and more preferably 420 MPa or more.

[0050] Furthermore, the fracture toughness (K1c) of the composite sintered body involved in this embodiment is 6.0 MPa·m. 1 / 2 ~8.8MPa·m 1 / 2 The preferred value is 6.2 MPa·m 1 / 2 ~8.8MPa·m 1 / 2 .

[0051] Furthermore, the Young's modulus of the composite sintered body involved in this embodiment can be 273 GPa to 594 GPa, preferably 330 GPa to 594 GPa, and more preferably 460 GPa to 594 GPa.

[0052] <Joint>

[0053] As described above, the composite sintered body according to this embodiment has a coefficient of thermal expansion similar to that of aluminum nitride. Therefore, the joint obtained by joining (e.g., metal bonding) a component (first component) formed from the composite sintered body according to this embodiment to a component (second component) made of aluminum nitride is less likely to peel off even when used under repeated thermal cycles of low and high temperatures.

[0054] This bonding material can be applied to components, for example, in semiconductor manufacturing apparatuses. Examples include components for semiconductor manufacturing apparatuses obtained by bonding a cooling plate (first component) made of a composite sintered body according to this embodiment and an electrostatic chuck (second component) made of aluminum nitride using a bonding material with aluminum or its alloy as the main component.

[0055] In this bonding assembly or semiconductor manufacturing device component, the difference in the linear thermal expansion coefficients between the first component and the second component is extremely small. Therefore, even when used under thermal cycling conditions, the first component is not easily detached from the second component.

[0056] Furthermore, the thermal conductivity of the first component formed from the composite sintered body according to this embodiment is sufficiently high, so that the heat efficiency of the second component formed from aluminum nitride can be well dissipated, thereby enabling efficient cooling of the second component.

[0057] Furthermore, the first component formed from the composite sintered body according to this embodiment has sufficiently high density, enabling the coolant to pass through its interior. In this case, the cooling efficiency of the second component is further improved.

[0058] Furthermore, the first component formed from the composite sintered body according to this embodiment has sufficiently high strength, and therefore can adequately withstand the stress generated during processing and bonding of components for manufacturing semiconductor manufacturing apparatus, as well as the stress generated due to temperature differences when the component is used as a completed component.

[0059] That is, by using the composite sintered body involved in this embodiment as a cooling plate for an electrostatic chuck, the service life of components for semiconductor manufacturing apparatus can be improved.

[0060] <Method for Manufacturing Composite Sintered Bodies>

[0061] Next, the method for manufacturing the composite sintered body according to this embodiment will be described. In this embodiment, in general, the desired composite sintered body is obtained in the following order: raw material powders weighed in a specified weight ratio are mixed to obtain a mixed powder, the mixed powder is shaped into a specified shape, and the resulting shaped body is hot-pressed and sintered.

[0062] As raw material powders, a total weight ratio of 100 wt% is prepared, comprising 5.7 wt% to 27.7 wt% SiC, 12.5 wt% to 55.3 wt% WSi2, 17.0 wt% to 55.7 wt% tungsten (W), or 49.5 wt% to 81.3 wt% WC. Preferably, the weight ratio of SiC is 6.0 wt% or more and 13.1 wt% or less.

[0063] The particle size of the SiC raw material powder is not particularly limited, but the average particle size is preferably 2μm to 35μm. In addition, only coarse particles (e.g., average particle size 15μm to 35μm), only fine particles (e.g., average particle size 2μm to 10μm), or a mixture of coarse and fine particles can be used.

[0064] It should be noted that when using SiC powder with an average particle size of less than 2 μm, if the SiC ratio in the mixed powder is relatively high, the surface area of ​​the SiC particles increases, thus reducing sinterability and making it difficult to obtain a dense sintered body. On the other hand, when using SiC powder with an average particle size of greater than 35 μm, even if sinterability is not an issue, it may be impossible to obtain sufficient strength.

[0065] For mixing raw material powders, dry mixing using a high-speed flow mixer can be exemplified. For instance, if the total weight of the raw material powders is approximately 300g to 500g, it is preferable to set the rotation speed of the stirring blades of the high-speed flow mixer to approximately 1000rpm to 1500rpm and mix for 10 to 15 minutes.

[0066] Alternatively, a wet mixing method using a nylon pot and an iron-core nylon ball with isopropanol as the solvent can be employed. In this case, the resulting slurry is dried at 110°C for 16 hours, for example, in a nitrogen atmosphere, and then sieved to obtain a mixed powder.

[0067] The hot pressing and firing of the molded body obtained by mixing powders is carried out in an inert atmosphere. Examples of inert atmospheres include: vacuum atmosphere, nitrogen atmosphere, argon atmosphere, etc.

[0068] The preferred pressure during hot pressing (compression pressure) is 225 kgf / cm². 2 ~300kgf / cm 2More preferably 250 kgf / cm 2 ~300kgf / cm 2 If the pressure is less than 200 kgf / cm 2 If the sintered body is not densified and the open porosity exceeds 1%, it is not ideal.

[0069] Regarding the temperature during hot pressing, the maximum temperature is preferably 1700℃~1850℃, and more preferably 1770℃~1830℃. It should be noted that if the maximum temperature is above 1900℃, the material melts, and a sintered body of the desired shape cannot be obtained, which is undesirable. On the other hand, if the maximum temperature is below 1700℃, sintering is not sufficient, which is also undesirable.

[0070] Regarding the specific pressure and temperature curves during hot pressing (hereinafter, hot pressing conditions), they can be appropriately set within the above-mentioned preferred range based on the composition of the powder mixture (weight ratio of each raw material powder), the particle size of the raw material powder, the size and shape of the molded body, etc. It should be noted that there is a trend where the smaller the weight ratio of silicon carbide in the mixed powder, the easier it is to sinter; therefore, the permissible range of hot pressing conditions for achieving densification is relatively wide. Furthermore, there is a trend where the permissible range of hot pressing conditions for achieving densification is wider when a mixture of coarse and fine silicon carbide particles is used compared to when only coarse particles are used.

[0071] In addition, the firing time can be set appropriately according to the hot pressing conditions, the size and shape of the molded body, etc. For example, when hot pressing and firing a disc-shaped molded body with a diameter of about 50 mm and a thickness of about 15 mm, it is preferable to set the holding time at the highest temperature within the range of 4 hours to 8 hours.

[0072] <Method for manufacturing the joint>

[0073] A method (joining method) for obtaining a bonded body formed by joining a first component made of a composite sintered body according to this embodiment and a second component made of aluminum nitride will be described. This joining method includes two types: metal joining, where the two components are joined by means of a metal bonding layer, and direct joining, where the two components are directly joined.

[0074] In the case of metal bonding, aluminum foil and dense aluminum nitride sintered body are sequentially stacked on the composite material sintered body according to this embodiment, which is processed into a predetermined shape such as a disc, to obtain a laminated body. The laminated body is then placed in a graphite mold for firing and hot-pressed under an inert gas atmosphere. Examples of inert atmospheres include: vacuum atmosphere, nitrogen atmosphere, argon atmosphere, etc.

[0075] The thickness of the metal foil should be approximately 180 μm to 220 μm. Furthermore, the laminated surfaces of the composite sintered body, the metal foil, and the aluminum nitride are preferably of the same shape.

[0076] Regarding hot pressing, the maximum temperature is set to 1770℃~1830℃, and the pressing pressure is set to 250kgf / cm. 2 ~300kgf / cm 2 This range of values ​​can be achieved by setting the holding time at the highest temperature to 4 to 8 hours. Based on this, a joint (metallic joint) without interface peeling or voids is obtained.

[0077] In the case of direct bonding, firstly, a powder mixture that yields the composition ratio of the composite sintered body according to this embodiment is subjected to uniaxial pressure molding under prescribed pressure conditions, thereby obtaining, for example, a disc-shaped molded body. Next, a dense aluminum nitride sintered body is laminated onto this molded body to obtain a laminated body. This laminated body is then placed in a graphite mold for firing and hot-pressed under an inert gas atmosphere. Examples of inert atmospheres include, for example, a vacuum atmosphere, a nitrogen atmosphere, and an argon atmosphere.

[0078] In this case, the laminated surfaces of the molded body and the aluminum nitride are preferably of the same shape.

[0079] Regarding hot pressing, the maximum temperature is set to 1770℃~1830℃, and the pressing pressure is set to 250kgf / cm. 2 ~300kgf / cm 2 This range of values ​​can be achieved by setting the holding time at the highest temperature to 4 to 8 hours. Based on this, a bond with no peeling or voids at the interface (direct bond) is obtained.

[0080] Example

[0081] Twenty-six experimental examples with varying combinations of raw material powder composition and hot-pressing conditions were used to attempt the fabrication and evaluation of composite sintered bodies. It should be noted that, in the following text, powder mixtures, molded bodies, and sintered bodies from the same experimental example are sometimes referred to collectively as "samples" without distinguishing their states.

[0082] <Raw Material Powder>

[0083] SiC, WSi2, W, and WC are prepared as raw material powders.

[0084] As raw material powders for SiC, three commercially available products with different particle sizes were prepared. Specifically, three powders with average particle sizes of 36 μm (hereinafter referred to as #500), 15 μm (hereinafter referred to as #1000), and 3 μm (hereinafter referred to as #6000) were prepared. The purity of all powders was above 99%.

[0085] Furthermore, commercially available powders with a purity of 99% or higher and an average particle size of 6 μm are used as raw material powders for WSi2. Commercially available powders with a purity of 99% or higher and an average particle size of 2 μm are used as raw material powders for W. Commercially available powders with a purity of 99% or higher and an average particle size of 2.3 μm are used as raw material powders for W.

[0086] <Preparation of Sintered Body>

[0087] Table 1 provides a summary of the raw material composition and hot-pressing conditions for all experimental examples. It should be noted that Table 1 also shows whether the samples melted during the hot-pressing process.

[0088] Table 1

[0089]

[0090] In all experimental examples, when preparing the composite sintered body, firstly, 300g of SiC raw material powder, WSi2 raw material powder, and WC raw material powder or W raw material powder were weighed according to the composition ratio (weight ratio) shown in Table 1. The weighed three powders were placed into a high-speed flow mixer with a capacity of 1.8L in the powder loading section and stirred and mixed at 1500rpm for 10 minutes to obtain a powder mixture.

[0091] The powder mixtures obtained from each experimental example were subjected to a concentration of 200 kgf / cm². 2 The pressure is applied uniaxially to form a disc-shaped molded body with a diameter of approximately 50 mm and a thickness of approximately 15 mm. The molded body is then placed in a graphite mold for firing.

[0092] The molded body is then subjected to hot pressing to obtain a sintered composite material. During hot pressing, seven different maximum temperatures are used: 1650℃, 1700℃, 1770℃, 1800℃, 1830℃, 1850℃, and 1900℃. The holding time at the highest temperature is set to 4 hours. Additionally, different pressures are applied, specifically 200 kgf / cm². 2 225 kgf / cm 2 250kgf / cm 2 and 300kgf / cm 2 These are the four pressure settings. It should be noted that pressure is applied starting when the firing temperature reaches 900°C. Figure 3 The highest temperature during hot pressing is set at 1800℃, and the pressure is set at 250 kgf / cm². 2 Examples of temperature and pressure curves.

[0093] <Composition and Properties of Sintered Composite Materials>

[0094] For the sintered composite materials obtained in each experimental example, the specific constituent phases and their composition ratios (contents) were calculated (using simplified quantitative methods). Furthermore, to evaluate properties, open porosity, bulk density, flexural strength, and coefficient of thermal expansion were measured.

[0095] Table 2 summarizes the composition ratio of the constituent phases of the sintered bodies of each experimental example, as well as the measured results of open porosity, bulk density, flexural strength, coefficient of thermal expansion, fracture toughness, Young's modulus, and thermal conductivity.

[0096] Table 2

[0097]

[0098] As shown in Table 2, Experimental Examples 1, 3-8, 10-12, 14-15, 17-19 and 21-25 are equivalent to the Examples, and the other examples are equivalent to the Comparative Examples.

[0099] Regarding the sintered composite materials belonging to the embodiments, fracture toughness (K1c value), Young's modulus, and thermal conductivity were also measured for a portion. These measurement results are also shown in Table 2.

[0100] On the other hand, regarding Experimental Examples 16 and 20, where the highest temperature during hot pressing was set to 1900°C, as shown in Table 1, the samples melted during the firing process, and the desired sintered body could not be obtained. Therefore, it was impossible to determine the constituent phase and measure any of the aforementioned properties.

[0101] (Identification and simplified quantitative analysis of constituent phases)

[0102] Except for Experimental Examples 16 and 20, the composite sintered bodies obtained in the above order were pulverized using a mortar and pestle, and X-ray diffraction measurements (θ-2θ measurements) were performed using a sealed-tube X-ray diffractometer (Bruker AXS D8 ADVANCE). The constituent phases (crystalline phases) of the composite sintered bodies were identified based on the peak patterns appearing in the obtained X-ray diffraction curves. CuKα rays were used as the characteristic X-rays, with a tube output of 40 kV and 40 mA, and a measurement range of 2θ = 5°–70°.

[0103] Furthermore, the composition ratio (content) of the crystalline phases contained in the composite sintered body was determined using a simplified quantitative method based on the intensity of the peaks appearing in the X-ray diffraction curve. The simplified quantitative method utilized the simplified curve fitting function (FPM Eval.) of Bruker AXS's powder diffraction data analysis software "EVA". This function calculates the weight ratio of the constituent phases using the I / Icor (intensity ratio relative to corundum diffraction intensity) of the ICDD PDF card of the identified crystalline phases.

[0104] (Determination of open porosity and bulk density)

[0105] The determination was performed using the Archimedes method with pure water as the medium.

[0106] (Determination of 4-point bending strength)

[0107] The determination was performed according to JIS-R1601.

[0108] (Determination of the coefficient of thermal expansion)

[0109] The average linear thermal expansion coefficient from 40°C to 550°C was calculated using the TD5020S (transverse differential expansion measurement method) manufactured by Bruker AXS Co., Ltd.

[0110] Specifically, the temperature was raised to 650℃ twice in an argon atmosphere at a heating rate of 20℃ / min. The average linear thermal expansion coefficient was calculated based on the data from the second measurement. The standard sample used was an alumina standard sample (99.7% purity, bulk density 3.9 g / cm³) provided with the apparatus. 3 (Length 20mm).

[0111] (Determination of fracture toughness value)

[0112] Fracture toughness was evaluated using the SEPB method according to JIS-R1607.

[0113] (Determination of Young's modulus)

[0114] Young's modulus was determined according to JIS R1602 (Test Method for Elastic Modulus of Fine Ceramics).

[0115] (Determination of thermal conductivity)

[0116] The determination was performed using the laser flash method.

[0117] <Details of each experimental case>

[0118] (Experimental Examples 1 to 5)

[0119] In Experiments 1 through 5, composite sintered bodies were prepared using SiC, WSi2, and W powders as raw materials. #500 and #6000 grade SiC powders were used.

[0120] Regarding the composition of raw materials, as shown in Table 1, the composition is as follows in both Experimental Example 1 and Experimental Example 2.

[0121] SiC (#500 grade): 18.0 wt%;

[0122] SiC (#6000 grade): 9.7 wt%;

[0123] WSi2: 55.3 wt%;

[0124] W: 17.0 wt%.

[0125] The results in Experiments 3 through 5 are as follows.

[0126] SiC (#500 grade): 15.8 wt%;

[0127] SiC (#6000 grade): 8.5 wt%;

[0128] WSi2: 20.0 wt%;

[0129] W: 55.7 wt%.

[0130] That is, in Experiments 3 to 5, compared with Experiments 1 and 2, the ratio of W was significantly increased, the ratio of WSi2 was significantly decreased, and the ratio of SiC was slightly decreased.

[0131] As for the hot pressing conditions, the maximum temperature was 1700℃ in Experiments 2 and 4, and 1800℃ in Experiments 1, 3, and 5. The pressing pressure was 250 kgf / cm³. 2 .

[0132] In Experiments 1 through 5, sintered bodies were obtained, and the constituent phases identified were only SiC, WSi2, W5Si3, and WC. The SiC content in the sintered body was less than 48.6 wt%.

[0133] In Experiment 1 and Experiments 3 to 5, the open porosity of the sintered body was less than 1%, but in Experiment 2, the open porosity significantly exceeded 1%. That is, dense composite sintered bodies were obtained in Experiment 1 and Experiments 3 to 5, but a dense composite sintered body could not be obtained in Experiment 2.

[0134] More specifically, in Experimental Examples 1, 3, and 5, where the maximum hot-pressing temperature was set at 1800°C, the open porosity was all below 1%. In contrast, in Experimental Examples 2 and 4, where the maximum hot-pressing temperature was 1700°C, only the latter had an open porosity below 1%. The difference between Experimental Examples 2 and 4 was only in the raw material composition. Therefore, it can be said that when W is used as the raw material, the maximum hot-pressing temperature must be set according to the raw material composition.

[0135] It should be noted that, except for Experimental Example 2, the coefficient of thermal expansion is in the range of 4.6 ppm / K to 5.6 ppm / K. On the other hand, the flexural strength in all experiments exceeded 200 MPa but was below 350 MPa. Furthermore, in Experimental Examples 1, 4, and 5, the fracture toughness value (K1c) was 6.0 MPa·m. 1 / 2 ~6.5MPa·m 1 / 2 Its Young's modulus is 448 GPa to 484 GPa. Additionally, its thermal conductivity is above 100 W / m·K.

[0136] The results of Experiments 1 to 5 demonstrate that when the weight ratio of SiC in the raw material powder is set to a value within the range of 5.7wt% to 27.7wt%, the weight ratio of WSi2 is set to a value within the range of 12.5wt% to 55.3wt%, and the weight ratio of W is set to a value within the range of 17.0wt% to 55.7wt%, by appropriately setting the hot pressing conditions according to the raw material composition, a sintered composite material containing 14.4wt% to 48.6wt% silicon carbide, with an open porosity of less than 1%, and a thermal expansion coefficient close to that of aluminum nitride can be obtained.

[0137] (Experimental Examples 6 to 14)

[0138] In Experiments 6 through 14, composite sintered bodies were prepared using SiC, WSi2, and WC powders as raw materials. Only grade #1000 SiC powder was used.

[0139] Regarding the composition of raw materials, as shown in Table 1, the composition of experimental examples 6 to 9 is as follows.

[0140] SiC (#1000 grade): 13.1 wt%;

[0141] WSi2: 22.2 wt%;

[0142] WC: 64.7 wt%.

[0143] In Experiment 10, the following is an example.

[0144] SiC (#1000 grade): 11.4 wt%;

[0145] WSi2: 39.1 wt%;

[0146] WC: 49.5 wt%.

[0147] The results in Experiments 11 through 13 are as follows.

[0148] SiC (#1000 grade): 9.1 wt%;

[0149] WSi2: 31.5 wt%;

[0150] WC: 59.4 wt%.

[0151] In Experiment 14, the following is an example.

[0152] SiC (#1000 grade): 8.5 wt%;

[0153] WSi2: 19.6 wt%;

[0154] WC: 71.9 wt%.

[0155] That is, in Experimental Examples 6 to 9, 10, 11 to 13, and 14, the following relationship exists in this order: the weight ratio of SiC and WSi2 in the raw materials decreases in turn, while the weight ratio of WC increases in turn.

[0156] On the other hand, as for the hot pressing conditions, the maximum temperature was set to 1770℃ in Experiment 7, 1830℃ in Experiment 8, and 1800℃ elsewhere. Furthermore, the pressing pressure was 200 kgf / cm² in both Experiment 9 and Experiment 13. 2 In addition, it is set at 250 kgf / cm². 2 .

[0157] That is, in Experimental Examples 6 to 8, only the maximum temperature during hot pressing differs. Similarly, in Experimental Examples 6 and 9, only the pressure during hot pressing differs. Likewise, in Experimental Examples 11, 12, and 13, only the pressure during hot pressing differs.

[0158] On the other hand, for Experimental Examples 6, 10, 11, 12, and 14, the hot-pressing conditions were the same, only the raw material composition was different.

[0159] The raw material composition and hot pressing conditions are the same for Experimental Examples 11 and 12.

[0160] In Experiments 6 through 14, sintered bodies were obtained, and the constituent phases identified were only SiC, WSi2, W5Si3, and WC. The SiC content in the sintered bodies was between 14.4 wt% and 48.6 wt% in all the experimental examples.

[0161] In addition, the pressing pressure during hot pressing is set to 200 kgf / cm. 2 In Experimental Examples 9 and 13, the open porosity significantly exceeded 1%. That is, a dense composite sintered body could not be obtained. On the other hand, when the pressing pressure was set to 250 kgf / cm²... 2 In Experimental Examples 6-8, 10-12, and 14, the open porosity was less than 0.1%. That is, an extremely dense composite sintered body was obtained.

[0162] It should be noted that in Experimental Examples 6-8, 10-12 and 14, which yielded dense composite sintered bodies, except for Experimental Example 7, the content of tungsten silicide (WSi2 and W5Si3) was greater than the content of silicon carbide (SiC).

[0163] Regarding the coefficient of thermal expansion, all experimental examples showed values ​​within the range of 4.6 ppm / K to 5.6 ppm / K and 4.9 ppm / K to 5.3 ppm / K. That is, the difference between the coefficient of thermal expansion and that of aluminum nitride is less than 0.2 ppm / K.

[0164] Furthermore, in the composite sintered bodies of Examples 6-8, 10-12, and 14, which were judged to be of extremely excellent density with an open porosity of less than 0.1%, a flexural strength exceeding 350 MPa was obtained. In addition, the fracture toughness (K1c) of these composite sintered bodies was 6.3 MPa·m. 1 / 2 ~7.9MPa·m 1 / 2 Regarding Young's modulus, except for Experimental Example 12 which was not measured, it ranged from 448 GPa to 520 GPa. Furthermore, regarding thermal conductivity, it was 98 W / m·K in Experimental Example 11, and above 100 W / m·K in all other examples.

[0165] (Experimental Examples 15 to 21)

[0166] In Experimental Examples 15 to 21, composite sintered bodies were prepared using SiC, WSi2, and WC powders as raw materials. As SiC powder, #500 and #6000 grades were used in Experimental Examples 15 to 17, while only #1000 grade was used in Experimental Examples 18 to 21.

[0167] Regarding the composition of raw materials, as shown in Table 1, the composition of raw materials in Experimental Examples 15 to 17 is as follows.

[0168] SiC (#500 grade): 5.0 wt%;

[0169] SiC (#6000 grade): 1.2 wt%;

[0170] WSi2: 12.5 wt%;

[0171] WC: 81.3 wt%.

[0172] In addition, the following applies to Experimental Examples 18 through 21.

[0173] SiC (#1000 grade): 6.2 wt%;

[0174] WSi2: 12.5 wt%;

[0175] WC: 81.3 wt%.

[0176] That is, in Experimental Examples 15 to 21, compared with Experimental Examples 6 to 14, the weight ratio of SiC and WSi2 was reduced, and the weight ratio of WC was increased. In addition, in Experimental Examples 15 to 17 and Experimental Examples 18 to 21, the overall weight ratio of SiC was the same, but the particle size of the powder used was different.

[0177] On the other hand, as for the hot pressing conditions, the maximum temperature was set to 1800℃ in Experiments 15 and 18, 1900℃ in Experiments 16 and 20, and 1830℃ in Experiments 17, 19, and 21. Furthermore, the pressing pressure was 250 kgf / cm³ in all cases. 2 .

[0178] Results: As mentioned above, in Experiment 16 and Experiment 20, where the maximum temperature during hot pressing was set to 1900℃, the samples melted during the firing process, and a sintered body could not be obtained.

[0179] In Experimental Examples 15, 17-19, and 21, where the highest hot-pressing temperature was 1800℃ or 1830℃, sintered bodies were obtained, and the constituent phases identified were only SiC, WSi2, W5Si3, and WC. Furthermore, the SiC content in the sintered bodies was between 14.4 wt% and 48.6 wt% in all the experimental examples.

[0180] Furthermore, in Experimental Examples 15, 17-19, and 21, the open porosity of the sintered body was all below 0.1%. That is, an extremely dense composite sintered body was obtained.

[0181] Furthermore, the coefficients of thermal expansion of these sintered bodies all fall within the range of 4.6 ppm / K to 5.6 ppm / K, specifically between 4.8 ppm / K and 4.9 ppm / K. That is, they achieve a coefficient of thermal expansion slightly smaller than that of aluminum nitride.

[0182] It should be noted that in Experimental Examples 15, 17-19 and 21, in which dense composite sintered bodies were obtained, the content of tungsten silicide (WSi2 and W5Si3) was greater than the content of silicon carbide (SiC).

[0183] Furthermore, the composite sintered bodies of Examples 15, 17-19, and 21, which were judged to have extremely excellent dense properties, exhibited a flexural strength exceeding 350 MPa. Moreover, the fracture toughness (K1c) of these composite sintered bodies was 7.5 MPa·m. 1 / 2 ~8.5MPa·m 1 / 2 The Young's modulus ranges from 523 GPa to 561 GPa. These values ​​are generally higher than those of Experimental Examples 6 to 14. In addition, the thermal conductivity is above 134 W / m·K, which is also higher than that of Experimental Examples 6 to 14.

[0184] (Experimental Examples 22-23)

[0185] In Experiments 22 and 23, composite sintered bodies were prepared using SiC, WSi2, and WC powders as raw materials. Only grade #1000 SiC powder was used.

[0186] Regarding the composition of raw materials, as shown in Table 1, Experimental Example 22 is as follows.

[0187] SiC (#1000 grade): 12.8 wt%;

[0188] WSi2: 13.5 wt%;

[0189] WC: 73.7 wt%.

[0190] In addition, Experiment 23 is as follows.

[0191] SiC (#1000 grade): 5.7 wt%;

[0192] WSi2: 26.7 wt%;

[0193] WC: 67.6 wt%.

[0194] On the other hand, regarding the hot pressing conditions, the maximum temperature is set at 1800℃, and the pressing pressure is set at 250 kgf / cm². 2 .

[0195] That is, compared with Experiments 6, 10, 11, 12, 14, and 18, which use the same hot pressing conditions, Experiments 22 and 23 differ in the combination of the weight ratios of SiC powder (#1000 grade), WSi2 powder, and WC powder used as raw materials.

[0196] Sintered bodies were obtained in all experimental examples, and the constituent phases identified were only SiC, WSi2, W5Si3, and WC. The SiC content in the sintered bodies was between 14.4 wt% and 48.6 wt% in all experimental examples.

[0197] In Experiment 23, the content of tungsten silicide (WSi2 and W5Si3) was greater than that of silicon carbide (SiC), whereas the opposite was true in Experiment 22.

[0198] The open porosity of the sintered body was less than 0.1% in both Experimental Example 22 and Experimental Example 23. That is, in all experimental examples, extremely dense composite sintered bodies were obtained.

[0199] On the other hand, the coefficient of thermal expansion of the sintered body met the range of 4.6ppm / K to 5.6ppm / K in all experimental examples, with the lower limit of 4.6ppm / K in experimental example 22.

[0200] In Experiment 23, the upper limit of the range was 5.6 ppm / K.

[0201] In addition, regarding the bending strength, it was 423 MPa in Experiment 22 and 424 MPa in Experiment 23. That is, all experimental examples exceeded 350 MPa, however, there was almost no difference between them.

[0202] On the other hand, regarding the fracture toughness (K1c), Young's modulus, and thermal conductivity, in Experimental Example 23, these values ​​were 8.2 MPa·m. 1 / 2 High values ​​such as 548 GPa and 134 W / m·K were observed, however, in Experimental Example 22, the values ​​stopped at 6.0 MPa·m. 1 / 2 Values ​​such as 332 GPa and 104 W / m·K.

[0203] Based on comparisons with other experimental examples, regarding Experiment 22, it is believed that the content of tungsten silicide (WSi2 and W5Si3) at 12.7 wt% has less impact on the properties of the sintered body than the content of silicon carbide (SiC) at 28.1 wt%. Furthermore, regarding Experiment 23, it is believed that the low weight ratio of SiC in the raw material powder (as low as 5.7 wt%) affects the properties of the sintered body.

[0204] (Experimental Examples 24-26)

[0205] In Experiments 24 to 26, composite sintered bodies were prepared using SiC, WSi2, and W powders as raw materials. #500 and #6000 grade SiC powders were used.

[0206] The composition of the raw materials is shown in Table 1, which is the same as that in Experimental Example 1 and Experimental Example 2, as follows.

[0207] SiC (#500 grade): 18.0 wt%;

[0208] SiC (#6000 grade): 9.7 wt%;

[0209] WSi2: 55.3 wt%;

[0210] W: 17.0 wt%.

[0211] As for the hot-pressing conditions, in Experiments 24 to 26, the combination of the maximum temperature and the pressing pressure were different from those in Experiments 1 to 5. In Experiment 24, the maximum temperature was set to 1850℃ and the pressing pressure was set to 225 kgf / cm². 2 In Experiment 25, the highest temperature was set to 1700℃ and the pressing pressure was set to 300 kgf / cm². 2 In Experiment 26, the highest temperature was set at 1650℃ and the pressing pressure was set at 300 kgf / cm². 2 .

[0212] Specifically, in Experiment 24, compared to Experiment 1, the maximum temperature was increased, while the pressing pressure was decreased. Furthermore, in Experiment 25, compared to Experiment 2 (the comparative example), the pressing pressure was increased. Additionally, in Experiment 26, compared to Experiment 2 (the comparative example), the maximum temperature was decreased, while the pressing pressure was increased.

[0213] In Experiments 24 to 26, sintered bodies were obtained, and the constituent phases were identified as only SiC, WSi2, W5Si3, and WC. Regarding the SiC content in the sintered bodies, it was less than 48.6 wt% in Experiments 24 and 25, but exceeded 48.6 wt% in Experiment 26, reaching 50.1 wt%.

[0214] Regarding the open porosity of the sintered body, it was less than 1% in Experimental Examples 24 and 25, but exceeded 1% in Experimental Example 26.

[0215] Furthermore, the coefficient of thermal expansion in Experiments 24 to 26 was 5.4 ppm / K, falling within the range of 4.6 ppm / K to 5.6 ppm / K. On the other hand, regarding flexural strength, Experiments 24 and 25 achieved 252 MPa, similar to Experiments 1 and 2; however, Experiment 26 stopped at 116 MPa. Additionally, the fracture toughness (K1c) and Young's modulus in Experiments 24 and 25 were similar to those in Experiment 1; however, their thermal conductivity was slightly higher than that of Experiment 1.

[0216] (Summary of Experiments 1 through 26)

[0217] The results of Experiments 1 to 26 demonstrate that when the weight ratio of SiC in the raw material powder is set to a value within the range of 5.7wt% to 27.7wt%, the weight ratio of WSi2 is set to a value within the range of 12.5wt% to 55.3wt%, and the weight ratio of WC is set to a value within the range of 49.5wt% to 81.3wt%, or the weight ratio of W is set to a value within the range of 17.0wt% to 55.7wt%, by appropriately setting the hot pressing conditions, a composite sintered body containing 14.4wt% to 48.6wt% silicon carbide, with an open porosity of less than 1%, and a thermal expansion coefficient close to that of aluminum nitride can be obtained.

[0218] Furthermore, it was stated that the dense composite sintered body possesses a four-point flexural strength of over 200 MPa and a tensile strength of 6.0 MPa·m. 1 / 2 ~8.8MPa·m 1 / 2 Fracture toughness within this range, Young's modulus within the range of 273 GPa to 594 GPa, and thermal conductivity above 90 W / m·K.

[0219] In particular, the results of Experimental Examples 6 to 23 also demonstrate that when the weight ratio of SiC in the raw material powder is set to a value in the range of 5.7wt% to 13.1wt%, the weight ratio of WSi2 is set to a value in the range of 12.5wt% to 39.1wt%, and the weight ratio of WC is set to a value in the range of 49.5wt% to 81.3wt%, an extremely excellent dense composite sintered body with an open porosity of less than 0.1% is obtained. Furthermore, the composite sintered body has an extremely excellent four-point flexural strength of more than 350 MPa.

Claims

1. A composite sintered body, characterized in that, It is composed of silicon carbide, tungsten silicide, and tungsten carbide. Contains more than 14.4 wt% and less than 48.6 wt% silicon carbide. The open porosity is less than 1%. The difference between the coefficient of thermal expansion of the composite sintered body at 40℃~550℃ and that of aluminum nitride at 40℃~550℃ is less than 0.5ppm / K.

2. The composite sintered body according to claim 1, characterized in that, The open porosity is less than 0.1%.

3. The composite sintered body according to claim 1, characterized in that, The surface of each crystalline particle of silicon carbide is covered by at least one of tungsten silicide or tungsten carbide, thereby crystalline particles of at least one of tungsten silicide or tungsten carbide are present in the gaps between the crystalline particles of silicon carbide.

4. The composite sintered body according to any one of claims 1 to 3, characterized in that, The content of tungsten silicide is greater than that of silicon carbide.

5. The composite sintered body according to any one of claims 1 to 3, characterized in that, The 4-point bending strength is above 200MPa.

6. The composite sintered body according to claim 5, characterized in that, The 4-point bending strength is above 350MPa.

7. The composite sintered body according to any one of claims 1 to 3, characterized in that, The thermal conductivity is above 90 W / m·K.

8. The composite sintered body according to any one of claims 1 to 3, characterized in that, The fracture toughness value is 6.0 MPa·m 1／2 ~8.8MPa·m 1／2 .

9. The composite sintered body according to any one of claims 1 to 3, characterized in that, Young's modulus ranges from 273 GPa to 594 GPa.

10. The composite sintered body according to claim 9, characterized in that, The Young's modulus is 460 GPa to 594 GPa.

11. A joint formed by joining a first component and a second component, The characteristic of the joint is that... The first component is formed from a composite sintered body. The sintered composite material is composed of silicon carbide, tungsten silicide, and tungsten carbide, containing more than 14.4 wt% and less than 48.6 wt% silicon carbide, with an open porosity of less than 1%. The second component is formed of aluminum nitride. The difference between the coefficient of thermal expansion of the first component at 40℃ to 550℃ and the coefficient of thermal expansion of the second component at 40℃ to 550℃ is less than 0.5ppm / K.

12. The joint according to claim 11, characterized in that, The porosity of the first component is less than 0.1%.

13. The joint according to claim 11 or 12, characterized in that, The first component and the second component are formed by metal bonding.

14. A component for a semiconductor manufacturing apparatus, comprising a bonding body formed by joining a first component and a second component. The component for the semiconductor manufacturing apparatus is characterized in that... The first component is a cooling component for cooling the second component, and is formed from a composite sintered body. The sintered composite material is composed of silicon carbide, tungsten silicide, and tungsten carbide, containing more than 14.4 wt% and less than 48.6 wt% silicon carbide, with an open porosity of less than 1%. The second component is formed of aluminum nitride. The difference between the coefficient of thermal expansion of the first component at 40℃ to 550℃ and the coefficient of thermal expansion of the second component at 40℃ to 550℃ is less than 0.5ppm / K.

15. The component for a semiconductor manufacturing apparatus according to claim 14, characterized in that, The porosity of the first component is less than 0.1%.

16. The component for a semiconductor manufacturing apparatus according to claim 14 or 15, characterized in that, The first component and the second component are formed by metal bonding.

17. A method for manufacturing a composite sintered body, characterized in that, The process includes the following steps: The mixing process involves mixing SiC powder, WSi2 powder, and WC powder or W powder to obtain a powder mixture. The molding process involves shaping the powder mixture into a predetermined shape to obtain a molded body. as well as The firing process involves hot-pressing and firing the molded body under an inactive atmosphere. In the mixing process, 5.7wt% to 27.7wt% of SiC powder, 12.5wt% to 55.3wt% of WSi2 powder, and 49.5wt% to 81.3wt% of WC powder or 17.0wt% to 55.7wt% of W powder are mixed in a total weight ratio of 100wt%. In the firing process, the maximum temperature is set to 1700℃~1850℃, and the pressing pressure is set to 225kgf / cm. 2 ~300kgf / cm 2 .

18. The method for manufacturing a composite sintered body according to claim 17, characterized in that, In the mixing process, 5.7wt% to 13.1wt% of SiC powder and 12.5wt% to 39.1wt% of WSi2 are mixed. The powder and 49.5 wt% to 81.3 wt% WC powder were mixed together in a total weight ratio of 100 wt%.

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