Composite material sintered body, bonded body, component for semiconductor manufacturing equipment, and method for manufacturing a composite material sintered body

Abstract

To provide a sintered composite material of dense quality, which is composed of a constituent phase different from conventional materials and has a linear thermal expansion coefficient difference with aluminum nitride equal to or smaller than that of conventional materials.SOLUTION: A sintered composite material comprises silicon carbide, tungsten silicide, and tungsten carbide, and contains 14.4 wt.% or more and 48.6 wt.% or less of silicon carbide, and has an open porosity of 1% or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a composite material sintered body. [Background technology]

[0002] Electrostatic chucks, which reach high temperatures during semiconductor processes, are fitted with cooling plates for heat dissipation. For example, a dense sintered composite body made of silicon carbide, titanium silicide, titanium silicon carbide, and titanium carbide is already known as a suitable component for a cooling plate when the electrostatic chuck material is alumina (see, for example, Patent Document 1). Such a composite sintered body has the characteristics of having a small difference in linear thermal expansion coefficient from alumina, as well as being dense and having high strength.

[0003] Furthermore, dense sintered composite materials composed of silicon carbide, titanium silicon carbide, and titanium carbide are already known (see, for example, Patent Document 2), which are suitable as components for cooling plates when the material of an electrostatic chuck is aluminum nitride. Such composite material sintered bodies have a small difference in linear thermal expansion coefficient with aluminum nitride, and are dense and have high strength. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2014-198662 [Patent Document 2] Japanese Patent Publication No. 2014-208567 [Overview of the project] [Problems that the invention aims to solve]

[0005] The coefficient of linear thermal expansion of aluminum nitride at 40°C to 570°C is 5.1 ppm / K, whereas the preferred range of the coefficient of linear thermal expansion at 40°C to 570°C of the composite material disclosed in Patent Document 2 is 5.4 ppm / K to 6.0 ppm / K. In a Ti-Si-C based composite material sintered body as disclosed in Patent Document 2, when attempting to achieve a coefficient of linear thermal expansion of 5.1 ppm / K, it is necessary to increase the amount of silicon carbide; in such a case, there arises a problem that the denseness of the composite material sintered body decreases, making it unsuitable for a cooling plate of an electrostatic chuck.

[0006] The present invention has been made in view of the above problems, and an object of the present invention is to provide a dense composite material sintered body that is composed of constituent phases different from conventional ones, has a difference in coefficient of linear thermal expansion from aluminum nitride that is equal to or smaller than that of conventional composite materials. [Means for Solving the Problems]

[0007] In order to solve the above problems, a first aspect of the present invention provides a composite material sintered body, which 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.

[0008] A second aspect of the present invention provides the composite material sintered body according to the first aspect, which is characterized in that a difference between the coefficient of thermal expansion at 40°C to 550°C of the composite material sintered body and the coefficient of thermal expansion at 40°C to 550°C of aluminum nitride is 0.5 ppm / K or less.

[0009] A third aspect of the present invention provides the composite material sintered body according to the second aspect, which is characterized by having an open porosity of 0.1% or less.

[0010] A fourth aspect of the present invention provides the composite material sintered body according to any one of the first to third aspects, wherein a surface of each silicon carbide crystal particle is covered with at least one of tungsten silicide and tungsten carbide, such that at least one crystal particle of tungsten silicide or tungsten carbide is present in gaps between the silicon carbide crystal particles.

[0011] A fifth aspect of the present invention provides the composite material sintered body according to any one of the first to fourth aspects, wherein a content of tungsten silicide is greater than a content of silicon carbide.

[0012] A sixth aspect of the present invention provides the composite material sintered body according to any one of the first to fifth aspects, wherein a four-point bending strength is 200 MPa or more.

[0013] A seventh aspect of the present invention provides the composite material sintered body according to the sixth aspect, wherein a four-point bending strength is 350 MPa or more.

[0014] An eighth aspect of the present invention provides the composite material sintered body according to any one of the first to seventh aspects, wherein a thermal conductivity is 90 W / m·K or more.

[0015] A ninth aspect of the present invention provides the composite material sintered body according to any one of the first to eighth aspects, wherein a fracture toughness value is 6.0 MPa·m 1 / 2 to 8.8 MPa·m 1 / 2 .

[0016] A tenth aspect of the present invention provides the composite material sintered body according to any one of the first to ninth aspects, wherein a Young's modulus ranges from 273 GPa to 594 GPa.

[0017] An eleventh aspect of the present invention provides the composite material sintered body according to the tenth aspect, wherein a Young's modulus ranges from 460 GPa to 594 GPa.

[0018] A twelfth aspect of the present invention is a jointed body formed by joining a first member and a second member, wherein the first member is made of a composite material 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 member is made of aluminum nitride.

[0019] A thirteenth aspect of the present invention is a joint according to the twelfth aspect, characterized in that the difference between the thermal expansion coefficient of the first member at 40°C to 550°C and the thermal expansion coefficient of the second member at 40°C to 550°C is 0.5 ppm / K or less.

[0020] A fourteenth aspect of the present invention is a joint according to the thirteenth aspect, characterized in that the open porosity of the first member is 0.1% or less.

[0021] A fifteenth aspect of the present invention is a joint according to any of the twelfth to fourteenth aspects, characterized in that the first member and the second member are joined by metal.

[0022] A sixteenth aspect of the present invention is a component for a semiconductor manufacturing apparatus comprising a joint formed by joining a first member and a second member, wherein the first member is a cooling member for cooling the second member and is made of a composite material sintered body composed of silicon carbide, tungsten silide, 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 member is made of aluminum nitride.

[0023] A 17th aspect of the present invention is a semiconductor manufacturing apparatus component according to the 16th aspect, characterized in that the difference between the thermal expansion coefficient of the first component at 40°C to 550°C and the thermal expansion coefficient of the second component at 40°C to 550°C is 0.5 ppm / K or less.

[0024] An eighteenth aspect of the present invention is a semiconductor manufacturing apparatus component according to the seventeenth aspect, characterized in that the open porosity of the first component is 0.1% or less.

[0025] A 19th aspect of the present invention is a semiconductor manufacturing apparatus component according to any of the 16th to 17th aspects, characterized in that the first component and the second component are joined by metal.

[0026] A 20th aspect of the present invention is a method for manufacturing a composite material sintered body, comprising: a mixing step of mixing SiC powder, WSi2 powder, and WC powder or W powder to obtain a powder mixture; a molding step of molding the powder mixture into a predetermined shape to obtain a molded body; and a firing step of hot-pressing the molded body in an inert atmosphere, wherein in the mixing step, 5.7 wt% to 27.7 wt% of SiC powder, 12.5 wt% to 55.3 wt% of WSi2 powder, and 49.5 wt% to 81.3 wt% of WC powder or 17.0 wt% to 55.7 wt% of W powder are mixed so that the total weight ratio is 100 wt%; and in the firing step, the maximum temperature is 1700°C to 1850°C and the press pressure is 225 kgf / cm². 2 ~300 kgf / cm² 2 It is characterized by being such.

[0027] A 21st aspect of the present invention is a method for manufacturing a composite material sintered body according to the 20th aspect, characterized in that, in the mixing step, 5.7 wt% to 13.1 wt% of SiC powder, 12.5 wt% to 39.1 wt% of WSi2 powder, and 49.5 wt% to 81.3 wt% of WC powder are mixed so that the total weight ratio is 100 wt%. [Effects of the Invention]

[0028] According to the first to eleventh, twentieth, and twentieth aspects of the present invention, a dense composite sintered body is obtained that is less prone to delamination even when bonded with aluminum nitride and used under thermal cycling.

[0029] Furthermore, according to the 12th to 19th aspects of the present invention, even if the bonded body is used under a thermal cycle, delamination of the members is less likely to occur, thus improving the service life of semiconductor manufacturing equipment components equipped with such bonded bodies. [Brief explanation of the drawing]

[0030] [Figure 1] This is an example of a cross-sectional SEM image of a composite material sintered body. [Figure 2] This graph shows the relationship between the silicon carbide content and the open porosity in a composite sintered body. [Figure 3] This is an example of a temperature and pressure profile in hot press firing. [Modes for carrying out the invention]

[0031] <Composite Material Sintered Body> The composite material sintered body according to this embodiment is a composite material sintered body containing silicon carbide (SiC), tungsten silicide, and tungsten carbide (WC) as crystalline phases. When the total weight ratio of these crystalline phases is 100 wt%, the composite material sintered body according to this embodiment contains 14.4 wt% to 48.6 wt% of silicon carbide (SiC). Preferably, the tungsten silicide content is greater than the silicon carbide content. Specifically, the tungsten silicide is WSi2 and W5Si3.

[0032] The presence of SiC, tungsten silicide, and tungsten carbide as crystalline phases in the composite material sintered body according to this embodiment is confirmed by X-ray diffraction measurement of the powder obtained by crushing the sintered body. Furthermore, the content of each substance is determined based on the diffraction peaks of the X-ray diffraction measurement profile (simplified quantitative values).

[0033] Furthermore, the composite material sintered body according to this embodiment is dense with an open porosity of 1% or less (dense composite material sintered body). The open porosity is measured by the Archimedes method using pure water as the medium.

[0034] More specifically, in the composite material sintered body according to this embodiment, the surface of each individual silicon carbide crystal grain is covered with at least one of tungsten silicide or tungsten carbide. As a result, at least one of tungsten silicide or tungsten carbide crystal grains is present in the gaps between the silicon carbide crystal grains.

[0035] Figure 1 shows an example of a cross-sectional SEM image of a composite material sintered body according to this embodiment. In Figure 1, images of four crystalline phases, SiC, WSi2, WC, and W5Si3, can be seen in order of decreasing brightness (darkness). More specifically, it can be seen that the individual SiC crystal grains, which are almost black, are separated from each other, and that the WSi2, WC, and W5Si3 crystal grains completely surround each of these crystal grains without any gaps.

[0036] In sintered bodies with a high silicon carbide content and high dispersion of silicon carbide particles, many pores can form between these particles. However, in the composite material sintered body according to this embodiment, the surface of the silicon carbide particles is covered with particles of other crystalline phases, so very few such pores are formed. As a result, the composite material sintered body according to this embodiment is dense and high-strength.

[0037] Preferably, the open porosity of the composite material sintered body according to this embodiment is 0.1% or less. A composite material sintered body satisfying this open porosity has extremely excellent density and extremely high strength.

[0038] Figure 2 is a graph showing the relationship between silicon carbide content and open porosity in various composite material sintered bodies produced under different manufacturing conditions. Specifically, the conditions for the maximum temperature and press pressure during hot pressing, which will be described later, were different, and in Figure 2, the data is plotted according to the maximum temperature during hot pressing. In Figure 2, it can be seen that the open porosity tends to increase as the silicon carbide content in the composite material sintered body increases. In particular, it can be seen that in the range of silicon carbide content of approximately 50 wt% or less, composite material sintered bodies with an open porosity of 1% or less can be produced by setting the manufacturing conditions appropriately. Furthermore, it can be seen that in the range of silicon carbide content of approximately 30 wt% or less, composite material sintered bodies with an open porosity of 0.1% or less can also be produced. On the other hand, when the silicon carbide content exceeds 50 wt%, it becomes difficult to obtain composite material sintered bodies with low open porosity, which is undesirable.

[0039] The linear thermal expansion coefficient of the composite material sintered body according to this embodiment is about the same as that of aluminum nitride (AlN). Hereafter, the linear thermal expansion coefficient will also be simply referred to as the thermal expansion coefficient.

[0040] Specifically, the thermal expansion coefficient of the composite material sintered body according to this embodiment at 40°C to 550°C is 0.5 ppm / K or less, compared to the average thermal expansion coefficient of aluminum nitride at 40°C to 550°C (5.1 ppm / K). More specifically, the thermal expansion coefficient of the composite material sintered body according to 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.

[0041] Furthermore, the composite material sintered body according to this embodiment has excellent thermal conductivity. Its thermal conductivity is 90 W / m·K or higher, preferably 100 W / m·K or higher.

[0042] The composite material sintered body according to this embodiment also exhibits excellent strength. Specifically, its four-point bending strength is 200 MPa or higher, preferably 350 MPa or higher, and more preferably 420 MPa or higher.

[0043] Furthermore, the fracture toughness value (K1c) of the composite material sintered body according to this embodiment is 6.0 MPa·m 1 / 2 ~8.8 MPa·m 1 / 2 Preferably, 6.2 MPa·m 1 / 2 ~8.8 MPa·m 1 / 2 That is the case.

[0044] Furthermore, the Young's modulus of the composite material sintered body according to this embodiment may be 273 GPa to 594 GPa, preferably 330 GPa to 594 GPa, and more preferably 460 GPa to 594 GPa.

[0045] <zygote> As described above, the composite material sintered body according to this embodiment has a coefficient of thermal expansion similar to that of aluminum nitride. Therefore, even if a joint formed by joining (for example, metal bonding) a member made of the composite material sintered body according to this embodiment (first member) to a member made of aluminum nitride (second member) is used under a thermal cycle in which low and high temperatures are repeatedly alternating, delamination of the two members is unlikely to occur.

[0046] Such a joint can be applied, for example, to components for semiconductor manufacturing equipment. For example, a component for semiconductor manufacturing equipment may be obtained by joining a cooling plate (first component) made of a composite material sintered body according to this embodiment and an electrostatic chuck (second component) made of aluminum nitride with a bonding material mainly composed of aluminum or an alloy thereof.

[0047] In such a joint or component for semiconductor manufacturing equipment, the difference in the coefficient of linear thermal expansion between the first and second members is extremely small, making it difficult for the first member to separate from the second member even when used under a thermal cycle.

[0048] Furthermore, since the first member made of a composite material sintered body according to this embodiment has a sufficiently high thermal conductivity, it can efficiently dissipate the heat from the second member made of aluminum nitride, and thus efficiently cool the second member.

[0049] Furthermore, the first member made of a composite material sintered body according to this embodiment has sufficiently high density and can be structured to allow a cooling liquid to pass through its interior. In this case, the cooling efficiency of the second member is further improved.

[0050] In addition, the first member made of a composite material sintered body according to this embodiment has sufficiently high strength, and can withstand stresses that occur during processing and joining for manufacturing semiconductor manufacturing equipment components, as well as stresses caused by temperature differences when the completed component is used.

[0051] In other words, by using the composite material sintered body according to this embodiment as a cooling plate for an electrostatic chuck, the service life of the semiconductor manufacturing equipment component can be improved.

[0052] <Method for manufacturing composite material sintered bodies> Next, a method for manufacturing a composite material sintered body according to this embodiment will be described. In this embodiment, a desired composite material sintered body is obtained by the following procedure: mixing raw material powders weighed in a predetermined weight ratio, molding the resulting mixed powder into a predetermined shape, and then hot-pressing the resulting molded body.

[0053] The raw material powder consists of 5.7 wt% to 27.7 wt% SiC, 12.5 wt% to 55.3 wt% WSi2, and 17.0 wt% to 55.7 wt% tungsten (W) or 49.5 wt% to 81.3 wt% WC, prepared so that the total weight ratio is 100 wt%. Preferably, the weight ratio of SiC is 6.0 wt% to 13.1 wt%.

[0054] The particle size of the SiC raw material powder is not particularly limited, but it is preferable that the average particle size is 2 μm to 35 μm. Furthermore, only coarse particles (for example, average particle size 15 μm to 35 μm) may be used, only fine particles (for example, average particle size 2 μm to 10 μm) may be used, or a mixture of coarse and fine particles may be used.

[0055] Note that when using SiC powder with an average particle diameter smaller than 2 µm, if the proportion of SiC in the mixed powder is large, the surface area of SiC particles increases, which lowers sinterability and makes it difficult to obtain a dense sintered body. On the other hand, when using SiC powder with an average particle diameter larger than 35 µm, even if there is no problem with sinterability, sufficient strength may not be obtained.

[0056] As for mixing of the raw material powders, dry mixing using a high-speed fluidized mixer is exemplified. For example, if the total weight of the raw material powders is about 300 g to 500 g, it is preferable to set the rotation speed of the stirring blade of the high-speed fluidized mixer to about 1000 rpm to 1500 rpm and perform stirring for 10 minutes to 15 minutes.

[0057] Alternatively, an embodiment may be adopted in which wet mixing is performed using isopropyl alcohol as a solvent, a nylon pot and nylon balls with an iron core. In such a case, the slurry obtained by mixing is dried at 110°C for 16 hours, for example, in a nitrogen stream, and then passed through a sieve to obtain a mixed powder.

[0058] Hot press firing of a compact obtained by molding the mixed powder is performed in an inert atmosphere. Examples of the inert atmosphere include a vacuum atmosphere, a nitrogen gas atmosphere, and an argon gas atmosphere.

[0059] The pressure during hot pressing (pressing pressure) is 225 kgf / cm 2 to 300 kgf / cm 2 is preferable, and 250 kgf / cm 2 to 300 kgf / cm 2 is more preferable. Setting the pressure to less than 200 kgf / cm 2 is not preferable because the sintered body does not densify and the open porosity exceeds 1%.

[0060] The temperature during hot pressing is preferably between 1700°C and 1850°C, and more preferably between 1770°C and 1830°C. A maximum temperature of 1900°C or higher is undesirable because the material melts, preventing the acquisition of a sintered body with the desired shape. Conversely, a maximum temperature below 1700°C is undesirable because sintering does not proceed sufficiently.

[0061] The specific pressure and temperature profiles during hot pressing (hereinafter referred to as "hot pressing conditions") should be appropriately set within the preferred range described above, depending on the composition of the powder mixture (weight ratio of each raw material powder), the particle size of the raw material powders, the size and shape of the molded body, etc. Note that the smaller the weight ratio of silicon carbide in the mixed powder, the easier sintering proceeds, and therefore the acceptable range of hot pressing conditions for achieving densification tends to be relatively wide. Furthermore, compared to using only coarse silicon carbide, using a mixture of coarse and fine silicon carbide tends to result in a relatively wider acceptable range of hot pressing conditions for achieving densification.

[0062] Furthermore, the firing time should be set appropriately according to the hot press conditions, the size and shape of the molded object, etc. For example, when a disc-shaped molded object with a diameter of 50 mm and a thickness of 15 mm is hot-pressed, it is preferable to set the holding time at the maximum temperature to a range of 4 to 8 hours.

[0063] <Method for manufacturing a jointed body> A method for obtaining a joined body by joining a first member made of a composite material sintered body according to this embodiment and a second member made of aluminum nitride (joining method) will be described. There are two types of joining methods: metallic joining, in which the two members are joined via a metallic joining layer, and direct joining, in which the two members are joined directly.

[0064] In the case of metal joining, for example, a composite material sintered body according to this embodiment, which has been processed into a predetermined shape such as a disc, is laminated in this order with an aluminum metal foil and a dense aluminum nitride sintered body. This laminate is then placed in a graphite mold for firing and hot-pressed in an inert gas atmosphere. Examples of inert atmospheres include a vacuum atmosphere, a nitrogen gas atmosphere, and an argon gas atmosphere.

[0065] The thickness of the metal foil should be approximately 180 μm to 220 μm. Furthermore, it is preferable that the laminated surfaces of the composite material sintered body, the metal foil, and the aluminum nitride are identical in shape.

[0066] Hot press firing is performed at a maximum temperature of 1770°C to 1830°C and a press pressure of 250 kgf / cm². 2 ~300 kgf / cm² 2 The temperature should be set to a range of values, and the holding time at the highest temperature should be 4 to 8 hours. This will result in a bonded body (metal bonded body) without delamination or voids at the interface.

[0067] In the case of direct bonding, first, a powder mixture having a composition ratio that allows for obtaining a composite material sintered body according to this embodiment is uniaxially pressed under predetermined pressure conditions to obtain, for example, a disc-shaped molded body. Subsequently, a laminate formed by laminating a dense aluminum nitride sintered body onto the molded body is placed in a graphite mold for firing and hot-pressed in an inert gas atmosphere. Examples of inert atmospheres include a vacuum atmosphere, a nitrogen gas atmosphere, and an argon gas atmosphere.

[0068] In such cases, it is preferable that the laminated surfaces of the molded body and the aluminum nitride be of the same shape.

[0069] Hot press firing is performed at a maximum temperature of 1770°C to 1830°C and a press pressure of 250 kgf / cm². 2 ~300 kgf / cm² 2 The temperature should be set to a range of values, and the holding time at the highest temperature should be 4 to 8 hours. This will result in a bonded body (direct bonded body) without delamination or voids at the interface. [Examples]

[0070] We attempted to fabricate and evaluate composite material sintered bodies in 26 experimental examples with different combinations of raw material powder composition and hot pressing conditions. Hereafter, the powder mixtures, molded bodies, and sintered bodies from the same experimental example may be referred to simply as "samples," without distinguishing their state.

[0071] <Raw material powder> SiC, WSi2, W, and WC were prepared as raw material powders.

[0072] Three commercially available SiC raw material powders 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 of them was 99% or higher.

[0073] Furthermore, for WSi2, a commercially available powder with a purity of 99% or higher and an average particle size of 6 μm was used as the raw material powder. For WC, a commercially available powder with a purity of 99% or higher and an average particle size of 2 μm was used as the raw material powder. For W, a commercially available powder with a purity of 99% or higher and an average particle size of 2.3 μm was used as the raw material powder.

[0074] <Fabrication of sintered bodies> Table 1 lists the raw material composition and hot-pressing conditions for all experimental examples. Table 1 also indicates whether or not the samples melted during hot-pressing.

[0075] [Table 1]

[0076] In all experimental examples, when preparing the composite material sintered body, first, 300g in total was weighed of SiC raw material powder, WSi2 raw material powder, and WC raw material powder or W raw material powder in the composition ratio (weight ratio) shown in Table 1. The weighed three types of powders were put into a high-speed fluid mixer with a powder input capacity of 1.8L, and stirred and mixed at 1500rpm for 10 minutes to obtain a powder mixture.

[0077] The powder mixtures obtained from each experimental example were subjected to a concentration of 200 kgf / cm³. 2 A disc-shaped molded body with a diameter of approximately 50 mm and a thickness of approximately 15 mm was produced by uniaxial pressure molding under the specified pressure. The produced molded body was then placed in a graphite mold for firing.

[0078] Then, a composite material sintered body was obtained by hot-press firing the molded body. In the hot-press firing, the maximum temperature was varied to seven levels: 1650°C, 1700°C, 1770°C, 1800°C, 1830°C, 1850°C, and 1900°C. The holding time at the maximum temperature was 4 hours. The pressure was 200 kgf / cm². 2 , 225 kgf / cm² 2 , 250 kgf / cm² 2 , and 300 kgf / cm² 2 The pressure was varied into four levels. Pressure application began when the firing temperature reached 900°C. Figure 3 shows the results when the maximum temperature in hot press firing was 1800°C and the pressure was 250 kgf / cm². 2 This is an example of the temperature and pressure profiles under those conditions.

[0079] <Composition and properties of composite sintered bodies> For each of the composite material sintered bodies obtained from the experimental examples, the constituent phases were identified and their composition ratios (contents) were calculated (simplified quantitative analysis). In addition, open porosity, bulk density, bending strength, and thermal expansion coefficient were measured to evaluate their properties.

[0080] Table 2 lists the composition ratio of the constituent phases and the measurement results for open porosity, bulk density, bending strength, thermal expansion coefficient, fracture toughness, Young's modulus, and thermal conductivity for each experimental example of the sintered body.

[0081] [Table 2]

[0082] As shown in Table 2, Experimental Examples 1, 3-8, 10-12, 14-15, 17-19, and 21-25 are examples, while the other examples are comparative examples.

[0083] For the composite material sintered bodies applicable to the examples, with some exceptions, the fracture toughness value (K1c value), Young's modulus, and thermal conductivity were also measured. These measurement results are also shown in Table 2.

[0084] On the other hand, in Experimental Examples 16 and 20, where the maximum temperature for hot-press firing was 1900°C, as shown in Table 1, the samples melted during firing, and sintered bodies of the desired shape could not be obtained. Therefore, it was not possible to identify the constituent phases or measure any of the above-mentioned properties.

[0085] (Identification and simplified quantitative analysis of constituent phases) Except for Experimental Examples 16 and 20, the composite material sintered bodies obtained by the above procedure were crushed in a mortar and pestle, and X-ray diffraction measurements (θ-2θ measurement) were performed using a sealed-tube X-ray diffractometer (Bruker AXS D8 ADVANCE). Based on the peak patterns that appeared in the obtained X-ray diffraction profiles, the constituent phases (crystalline phases) of the composite material sintered bodies were identified. CuKα rays were used as the characteristic X-ray, the tube output was set to 40kV and 40mA, and the measurement range was 2θ = 5° to 70°.

[0086] Furthermore, the composition ratio (content) of the crystalline phases contained in the composite sintered body was determined by a simplified quantitative analysis based on the intensity of the peaks appearing in the X-ray diffraction profile. For this simplified analysis, the simplified profile fitting function (FPM Eval.) of Bruker AXS's powder diffraction data analysis software "EVA" was used. This function calculates the weight ratio of the constituent phases using the I / Icor (intensity ratio to the diffraction intensity of corundum) from the ICDD PDF card of the identified crystalline phase.

[0087] (Measurement of open porosity and bulk density) The measurement was performed using the Archimedes process with pure water as the medium.

[0088] (Measurement of 4-point bending strength) Measurements were taken in accordance with JIS-R1601.

[0089] (Measurement of thermal expansion coefficient) The average linear thermal expansion coefficient was calculated at temperatures ranging from 40°C to 550°C using a Bruker AXS TD5020S (horizontal differential expansion measurement method).

[0090] Specifically, the temperature was increased twice to 650°C in an argon atmosphere at a heating rate of 20°C / min, and the average linear thermal expansion coefficient was calculated from the data from the second measurement. The standard sample used was the alumina standard sample provided with the instrument (purity 99.7%, bulk density 3.9 g / cm³). 3 (A 20mm length was used.)

[0091] (Measurement of fracture toughness) Fracture toughness was evaluated using the SEPB method in accordance with JIS-R1607.

[0092] (Measurement of Young's modulus) The Young's modulus was measured in accordance with JIS R1602 (Test method for the elastic modulus of fine ceramics).

[0093] (Measurement of thermal conductivity) The measurement was performed using the laser flash method.

[0094] <Details of each experimental example> (Experimental Examples 1-5) In Experimental Examples 1 to 5, composite material sintered bodies were fabricated using SiC, WSi2, and W powders as raw materials. For the SiC powder, #500 and #6000 grades were used.

[0095] As shown in Table 1, the raw material composition was the same for both Experimental Example 1 and Experimental Example 2. SiC (#500 products): 18.0wt%; SiC (#6000 products): 9.7wt%; WSi2: 55.3 wt%; W:17.0wt%; That's what I decided.

[0096] In Experimental Examples 3 to 5, the following is common: SiC (#500 products): 15.8wt%; SiC (#6000 products): 8.5wt%; WSi2:20.0wt%; W: 55.7 wt%; That's what I decided.

[0097] In other words, in Experimental Examples 3 to 5, the ratio of W was significantly increased and the ratio of WSi2 was significantly decreased compared to Experimental Examples 1 and 2, while the amount of SiC was also slightly reduced.

[0098] For hot pressing conditions, the maximum temperature was set to 1700°C for Experimental Examples 2 and 4, and to 1800°C for Experimental Examples 1, 3, and 5. The press pressure was consistently 250 kgf / cm². 2 That's what I decided.

[0099] In all of Experimental Examples 1 to 5, sintered bodies were obtained, and only SiC, WSi2, W5Si3, and WC were identified as constituent phases. The SiC content in the sintered bodies was 48.6 wt% or less.

[0100] However, while the open porosity of the sintered bodies in Experimental Examples 1 and 3-5 was less than 1%, the open porosity of the sintered body in Experimental Example 2 was significantly higher than 1%. In other words, dense composite material sintered bodies were obtained in Experimental Examples 1 and 3-5, but not in Experimental Example 2.

[0101] More specifically, in Experimental Examples 1, 3, and 5, where the maximum temperature during hot-press firing was 1800°C, the open porosity was 1% or less in all cases. In contrast, in Experimental Examples 2 and 4, where the maximum temperature during hot-press firing was 1700°C, only the latter achieved an open porosity of 1% or less. Since the only difference between Experimental Example 2 and Experimental Example 4 is the raw material composition, it can be said that when using W as a raw material, it is necessary to set the maximum temperature during hot-press firing according to the raw material composition.

[0102] Except for Experimental Example 2, the coefficient of thermal expansion was within the range of 4.6 ppm / K to 5.6 ppm / K. On the other hand, the bending strength exceeded 200 MPa in all experimental examples but fell below 350 MPa. In addition, the fracture toughness value (K1c) was 6.0 MPa·m in Experimental Examples 1, 4, and 5. 1 / 2 ~6.5 MPa·m 1 / 2 The Young's modulus was 448 GPa to 484 GPa. Furthermore, the thermal conductivity was 100 W / m·K or higher.

[0103] The results of Experimental Examples 1 to 5 show that when the weight ratio of SiC in the raw material powder is set to a value in the range of 5.7 wt% to 27.7 wt%, the weight ratio of WSi2 is set to a value in the range of 12.5 wt% to 55.3 wt%, and the weight ratio of W is set to a value in the range of 17.0 wt% to 55.7 wt%, by appropriately setting the hot pressing conditions according to the raw material composition, a composite material sintered body can be obtained that contains 14.4 wt% to 48.6 wt% silicon carbide, is dense with an open porosity of 1% or less, and has a thermal expansion coefficient close to that of aluminum nitride.

[0104] (Experimental Examples 6-14) In Experimental Examples 6 to 14, composite material sintered bodies were fabricated using SiC, WSi2, and WC powders as raw materials. Only #1000 grade SiC powder was used.

[0105] As shown in Table 1, the raw material composition was common to Experimental Examples 6 to 9. SiC (#1000 products): 13.1wt%; WSi2:22.2wt%; WC: 64.7 wt%; That's what I decided.

[0106] In Experimental Example 10, SiC (#1000 products): 11.4wt%; WSi2: 39.1 wt%; WC: 49.5 wt%; That's what I decided.

[0107] In Experimental Examples 11 to 13, the following was common: SiC (#1000 products): 9.1wt%; WSi2: 31.5 wt%; WC: 59.4 wt%; That's what I decided.

[0108] In Experimental Example 14, SiC (#1000 products): 8.5wt%; WSi2: 19.6 wt%; WC: 71.9 wt%; That's what I decided.

[0109] In other words, in Experimental Examples 6-9, Experimental Example 10, Experimental Examples 11-13, and Experimental Example 14, the weight ratio of SiC and WSi2 in the raw materials decreases in that order, while the weight ratio of WC increases.

[0110] On the other hand, for the hot press conditions, the maximum temperature was set to 1770°C for Experimental Example 7, and to 1830°C for Experimental Example 8, while the maximum temperature was set to 1800°C for all other experiments. Furthermore, the press pressure was 200 kgf / cm² in Experimental Examples 9 and 13. 2 Other than that, 250 kgf / cm² 2 That's what I decided.

[0111] In other words, the only difference between Experimental Examples 6 to 8 is the maximum temperature during hot-press firing. Also, the only difference between Experimental Example 6 and Experimental Example 9 is the pressure during hot-press firing. Similarly, the only difference between Experimental Examples 11, 12, and 13 is the pressure during hot-press firing.

[0112] On the other hand, in Experimental Examples 6, 10, 11, 12, and 14, the hot pressing conditions were the same, with only the raw material composition being different.

[0113] Experimental Example 11 and Experimental Example 12 share the same raw material composition and hot pressing conditions.

[0114] In all of Experimental Examples 6 to 14, sintered bodies were obtained, and only SiC, WSi2, W5Si3, and WC were identified as constituent phases. The SiC content in the sintered bodies was within the range of 14.4 wt% to 48.6 wt% in all experimental examples.

[0115] Furthermore, the press pressure during hot press firing is set to 200 kgf / cm². 2 In experimental examples 9 and 13, the open porosity significantly exceeded 1%. In other words, a dense composite sintered body was not obtained. On the other hand, when the press pressure was 250 kgf / cm², 2 In experimental examples 6-8, 10-12, and 14, the open porosity was 0.1% or less. In other words, an extremely dense composite sintered body was obtained.

[0116] Furthermore, in Experimental Examples 6-8, 10-12, and 14, where dense composite sintered bodies were obtained, the content of tungsten silicide (WSi2 and W5Si3) was greater than the content of silicon carbide (SiC), except for Experimental Example 7.

[0117] Regarding the coefficient of thermal expansion, in all experimental examples, the values ​​were within the range of 4.9 ppm / K to 5.3 ppm / K, satisfying the range of 4.6 ppm / K to 5.6 ppm / K. In other words, the difference from the coefficient of thermal expansion of aluminum nitride was 0.2 ppm / K or less.

[0118] Furthermore, in the composite material sintered bodies of Experimental Examples 6-8, 10-12, and 14, which were judged to be extremely dense with an open porosity of 0.1% or less, a bending strength exceeding 350 MPa was obtained. In addition, the fracture toughness value (K1c) of these composite material sintered bodies was 6.3 MPa·m. 1 / 2 ~7.9 MPa·m 1 / 2 The Young's modulus was between 448 GPa and 520 GPa, except for Experimental Example 12, which was not measured. Regarding thermal conductivity, it was 100 W / m·K or higher, except for Experimental Example 11, where it was 98 W / m·K.

[0119] (Experimental Examples 15-21) In Experimental Examples 15 to 21, composite material sintered bodies were fabricated using SiC, WSi2, and WC powders as raw materials. For 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.

[0120] The raw material composition is common to Experimental Examples 15 to 17, as shown in Table 1. SiC (#500 products): 5.0wt%; SiC (#6000 products): 1.2wt%; WSi2: 12.5 wt%; WC: 81.3 wt%; That's what I decided.

[0121] Furthermore, in Experimental Examples 18 to 21, SiC (#1000 products): 6.2wt%; WSi2: 12.5 wt%; WC: 81.3 wt%; That's what I decided.

[0122] Specifically, in Experimental Examples 15 to 21, the weight ratio of SiC to WSi2 was reduced and the weight ratio of WC was increased compared to Experimental Examples 6 to 14. Furthermore, while the overall weight ratio of SiC remained the same in Experimental Examples 15 to 17 and Experimental Examples 18 to 21, the particle size of the powder used was different.

[0123] On the other hand, for hot pressing conditions, the maximum temperature was set to 1800°C for Experimental Examples 15 and 18, to 1900°C for Experimental Examples 16 and 20, and to 1830°C for Experimental Examples 17, 19, and 21. The pressing pressure was consistently set to 250 kgf / cm². 2 That's what I decided.

[0124] As a result, as described above, in Experimental Examples 16 and 20, where the maximum temperature during hot-press firing was 1900°C, the sample melted during firing, and no sintered body was obtained.

[0125] In Experimental Examples 15, 17-19, and 21, where the maximum temperature during hot-press firing was 1800°C or 1830°C, sintered bodies were obtained in all cases, and only SiC, WSi2, W5Si3, and WC were identified as constituent phases. Furthermore, the SiC content in the sintered bodies was within the range of 14.4 wt% to 48.6 wt% in all of these experimental examples.

[0126] Furthermore, in Experimental Examples 15, 17-19, and 21, the open porosity of the sintered body was 0.1% or less in all cases. In other words, an extremely dense composite material sintered body was obtained.

[0127] Furthermore, the thermal expansion coefficients of these sintered bodies all fell within the range of 4.8 ppm / K to 4.9 ppm / K, which is within the range of 4.6 ppm / K to 5.6 ppm / K. In other words, values ​​slightly smaller than those of aluminum nitride were obtained.

[0128] 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).

[0129] In addition, the composite material sintered bodies of Experimental Examples 15, 17-19, and 21, which were judged to be of extremely high density, achieved bending strengths exceeding 350 MPa. Furthermore, the fracture toughness value (K1c) of these composite material sintered bodies was 7.5 MPa·m. 1 / 2 ~8.5 MPa·m 1 / 2 The Young's modulus was 523 GPa to 561 GPa. These values ​​were generally higher than those observed in Experimental Examples 6 to 14. Furthermore, the thermal conductivity was 134 W / m·K or higher, which was also higher than that observed in Experimental Examples 6 to 14.

[0130] (Experimental Examples 22-23) In Experimental Examples 22 and 23, composite material sintered bodies were fabricated using SiC, WSi2, and WC powders as raw materials. Only #1000 grade SiC powder was used.

[0131] As shown in Table 1, in Experimental Example 22, the raw material composition was as follows: SiC (#1000 products): 12.8wt%; WSi2: 13.5 wt%; WC: 73.7 wt%; That's what I decided.

[0132] Furthermore, in experimental example 23, SiC (#1000 products): 5.7wt%; WSi2: 26.7 wt%; WC: 67.6 wt%; That's what I decided.

[0133] On the other hand, the hot press conditions were common to both: a maximum temperature of 1800°C and a press pressure of 250 kgf / cm². 2 That's what I decided.

[0134] In other words, both Experimental Examples 22 and 23 are similar to Experimental Examples 6, 10, 11, 12, 14, and 18, which share the same hot-pressing conditions, but differ in the weight ratio combination of the raw materials: SiC powder (#1000 grade), WSi2 powder, and WC powder.

[0135] In all experimental examples, sintered bodies were obtained, and only SiC, WSi2, W5Si3, and WC were identified as constituent phases. The SiC content in the sintered bodies was within the range of 14.4 wt% to 48.6 wt% in all of these experimental examples.

[0136] However, in Experimental Example 23, the content of tungsten silicide (WSi2 and W5Si3) was greater than the content of silicon carbide (SiC), while in Experimental Example 22, the opposite was true.

[0137] The open porosity of the sintered bodies was 0.1% or less in both Experimental Example 22 and Experimental Example 23. In other words, in both experimental examples, extremely dense composite material sintered bodies were obtained.

[0138] On the other hand, the thermal expansion coefficient of the sintered body was within the range of 4.6 ppm / K to 5.6 ppm / K in all experimental examples, but in experimental example 22 it was at the lower limit of the range, 4.6 ppm / K, and in experimental example 23 it was at the upper limit of the range, 5.6 ppm / K.

[0139] Furthermore, the bending strength was 423 MPa in experimental example 22 and 424 MPa in experimental example 23. In other words, both experimental examples exceeded 350 MPa, but there was almost no difference between them.

[0140] On the other hand, the fracture toughness value (K1c), Young's modulus, and thermal conductivity in Example 23 were 8.2 MPa·m, respectively. 1 / 2 The values ​​were high, at 548 GPa and 134 W / m·K, but in Example 22, they were 6.0 MPa·m. 1 / 2 The values ​​remained at 332 GPa and 104 W / m·K.

[0141] In comparison with other experimental examples, it is possible that the low content of tungsten silicide (WSi2 and W5Si3) at 12.7 wt% compared to the silicon carbide (SiC) content of 28.1 wt% in Experimental Example 22 may have affected the properties of the sintered body. Similarly, in Experimental Example 23, the low weight ratio of SiC in the raw material powder (5.7 wt%) may have affected the properties of the sintered body.

[0142] (Experimental Examples 24-26) In Experimental Examples 24 to 26, composite material sintered bodies were fabricated using SiC, WSi2, and W powders as raw materials. For the SiC powder, #500 and #6000 grades were used.

[0143] The raw material composition is the same as in Experimental Examples 1 and 2, as shown in Table 1. SiC (#500 products): 18.0wt%; SiC (#6000 products): 9.7wt%; WSi2: 55.3 wt%; W:17.0wt%; That's what I decided.

[0144] For the hot press conditions, the combination of maximum temperature and press pressure was different in Experimental Examples 24 through 26 compared to Experimental Examples 1 through 5. In Experimental Example 24, the maximum temperature was set to 1850°C and the press pressure to 225 kgf / cm². 2 In Experimental Example 25, the maximum temperature was set to 1700°C and the press pressure to 300 kgf / cm². 2 In Experimental Example 26, the maximum temperature was set to 1650°C and the press pressure to 300 kgf / cm². 2 That's what I decided.

[0145] Specifically, in Experimental Example 24, the maximum temperature was increased while the press pressure was decreased compared to Experimental Example 1. Furthermore, in Experimental Example 25, the press pressure was increased compared to the comparative example, Experimental Example 2. Additionally, in Experimental Example 26, the maximum temperature was decreased while the press pressure was increased compared to the comparative example, Experimental Example 2.

[0146] Sintered bodies were obtained in all of Experimental Examples 24 to 26, and only SiC, WSi2, W5Si3, and WC were identified as constituent phases. However, while the SiC content in the sintered bodies was 48.6 wt% or less in Experimental Examples 24 and 25, it was 50.1 wt% in Experimental Example 26, exceeding 48.6 wt%.

[0147] The open porosity of the sintered body was below 1% in Experimental Examples 24 and 25, but it was above 1% in Experimental Example 26.

[0148] Furthermore, the coefficient of thermal expansion was 5.4 ppm / K in all of Experimental Examples 24 to 26, satisfying the range of 4.6 ppm / K to 5.6 ppm / K. On the other hand, the bending strength was 252 MPa in Experimental Examples 24 and 25, similar to Experimental Examples 1 and 2, but remained at 116 MPa in Experimental Example 26. In addition, the fracture toughness value (K1c) and Young's modulus of Experimental Examples 24 and 25 were similar to those of Experimental Example 1, but the thermal conductivity was slightly higher than that of Experimental Example 1.

[0149] (Summary of Experimental Examples 1 to 26) The results of Experimental Examples 1 to 26 show that when the weight ratio of SiC in the raw material powder is set to a value in the range of 5.7 wt% to 27.7 wt%, the weight ratio of WSi2 is set to a value in the range of 12.5 wt% to 55.3 wt%, and the weight ratio of WC is set to a value in the range of 49.5 wt% to 81.3 wt%, or the weight ratio of W is set to a value in the range of 17.0 wt% to 55.7 wt%, by appropriately setting the hot pressing conditions, a composite material sintered body containing 14.4 wt% to 48.6 wt% silicon carbide, having a dense texture with an open porosity of 1% or less, and having a thermal expansion coefficient close to that of aluminum nitride, can be obtained.

[0150] Furthermore, the dense composite material sintered body exhibits a four-point bending strength of 200 MPa or more and 6.0 MPa·m 1 / 2 ~8.8 MPa·m 1 / 2 It also demonstrates that the material satisfies the following requirements: fracture toughness within a certain range, Young's modulus within the range of 273 GPa to 594 GPa, and thermal conductivity of 90 W / m·K or higher.

[0151] In particular, the results of Experimental Examples 6 to 23 show that when the weight ratio of SiC in the raw material powder is set to a value in the range of 5.7 wt% to 13.1 wt%, the weight ratio of WSi2 is set to a value in the range of 12.5 wt% to 39.1 wt%, and the weight ratio of WC is set to a value in the range of 49.5 wt% to 81.3 wt%, an extremely dense composite material sintered body with an open porosity of 0.1% or less can be obtained. Furthermore, it is shown that such a composite material sintered body has an excellent four-point bending strength of 350 MPa or more.

Claims

1. It is composed of silicon carbide, tungsten silicide, and tungsten carbide. It contains silicon carbide in an amount of 14.4 wt% to 48.6 wt%, The open porosity is 1% or less. A composite material sintered body characterized by the above.

2. A composite material sintered body according to claim 1, The difference between the thermal expansion coefficient of 40°C to 550°C and the thermal expansion coefficient of aluminum nitride in the same range is 0.5 ppm / K or less. A composite material sintered body characterized by the above.

3. A composite material sintered body according to claim 2, The open porosity is 0.1% or less. A composite material sintered body characterized by the above.

4. A composite material sintered body according to any one of claims 1 to 3, The surface of each individual silicon carbide crystal grain is covered with at least one of tungsten silicide or tungsten carbide, so that at least one of the tungsten silicide or tungsten carbide crystal grains is present in the gaps between the silicon carbide crystal grains. A composite material sintered body characterized by the above.

5. A composite material sintered body according to any one of claims 1 to 3, The tungsten silicide content is greater than the silicon carbide content. A composite material sintered body characterized by the above.

6. A composite material sintered body according to any one of claims 1 to 3, The four-point bending strength is 200 MPa or more. A composite material sintered body characterized by the above.

7. A composite material sintered body according to claim 6, The four-point bending strength is 350 MPa or more. A composite material sintered body characterized by the above.

8. A composite material sintered body according to any one of claims 1 to 3, The thermal conductivity is 90 W / m·K or higher. A composite material sintered body characterized by the above.

9. A composite material sintered body according to any one of claims 1 to 3, The fracture toughness value is 6.0 MPa·m １／２ ~8.8 MPa·m １／２ That is, A composite material sintered body characterized by the above.

10. A composite material sintered body according to any one of claims 1 to 3, The Young's modulus is between 273 GPa and 594 GPa. A composite material sintered body characterized by the above.

11. A composite material sintered body according to claim 10, The Young's modulus is between 460 GPa and 594 GPa. A composite material sintered body characterized by the above.

12. A jointed body formed by joining a first member and a second member, The first member is It is composed of silicon carbide, tungsten silicide, and tungsten carbide. It contains silicon carbide in an amount of 14.4 wt% to 48.6 wt%, The open porosity is 1% or less. It consists of a composite material sintered body, The second member is made of aluminum nitride. A joint characterized by the following features.

13. The joint according to claim 12, The difference between the thermal expansion coefficient of the first member at 40°C to 550°C and the thermal expansion coefficient of the second member at 40°C to 550°C is 0.5 ppm / K or less. A joint characterized by the following features.

14. The joint according to claim 13, The open porosity of the first member is 0.1% or less. A joint characterized by the following features.

15. A joint according to any one of claims 12 to 14, The first member and the second member are joined together by metal, A joint characterized by the following features.

16. A semiconductor manufacturing apparatus component comprising a joint formed by joining a first member and a second member, The first member is a cooling member for cooling the second member, It is composed of silicon carbide, tungsten silicide, and tungsten carbide. It contains silicon carbide in an amount of 14.4 wt% to 48.6 wt%, The open porosity is 1% or less. It consists of a composite material sintered body, The second member is made of aluminum nitride. A component for semiconductor manufacturing equipment characterized by the following features.

17. A semiconductor manufacturing apparatus component according to claim 16, The difference between the thermal expansion coefficient of the first member at 40°C to 550°C and the thermal expansion coefficient of the second member at 40°C to 550°C is 0.5 ppm / K or less. A component for semiconductor manufacturing equipment characterized by the following features.

18. A semiconductor manufacturing apparatus component according to claim 17, The open porosity of the first member is 0.1% or less. A component for semiconductor manufacturing equipment characterized by the following features.

19. A semiconductor manufacturing apparatus component according to any one of claims 16 to 18, The first member and the second member are joined together by metal, A component for semiconductor manufacturing equipment characterized by the following features.

20. A method for manufacturing a composite material sintered body, SiC powder and WSi ２ A mixing step of mixing powder with WC powder or W powder to obtain a powder mixture, A molding step to obtain a molded body by molding the powder mixture into a predetermined shape, A firing step in which the molded body is hot-pressed and fired in an inert atmosphere, Equipped with, In the aforementioned mixing step, 5.7 wt% to 27.7 wt% of SiC powder and 12.5 wt% to 55.3 wt% of WSi ２ The powder is mixed with 49.5 wt% to 81.3 wt% WC powder or 17.0 wt% to 55.7 wt% W powder, so that the total weight ratio is 100 wt%. In the aforementioned firing process, the maximum temperature is set to 1700°C to 1850°C, and the press pressure is set to 225 kgf / cm². ２ ~300kgf / cm ２ Let it be, A method for producing a composite material sintered body, characterized by the above.

21. A method for manufacturing a composite material sintered body according to claim 20, In the aforementioned mixing step, 5.7 wt% to 13.1 wt% of SiC powder and 12.5 wt% to 39.1 wt% of WSi ２ The powder and WC powder in an amount of 49.5 wt% to 81.3 wt% are mixed so that the total weight ratio is 100 wt%. A method for producing a composite material sintered body, characterized by the above.

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