Silicon carbide aluminum composite material and method for producing silicon carbide aluminum composite material

Abstract

The present invention provides a silicon carbide aluminum composite material and construction body that has the characteristics of being composited with metallic aluminum or an aluminum alloy that has a high silicon carbide (SiC) content and thermal conductivity, a thermal expansion coefficient similar to that of alumina with no significant difference in thermal expansion, and a melting point of approximately 570°C or higher, and that can be brazed at temperatures of 570°C or higher. [Solution] A composite material is a silicon carbide aluminum composite material and construction, which is formed by impregnating a porous molded body with a volume fraction of SiC of 75% or more, formed from SiC powder obtained by mixing SiC powder with a particle size of 100 μm or more and one or more types of SiC powder with a particle size of 50 μm or less, with metallic aluminum having a melting point of 570°C or more and containing less than 3 wt% impurities other than aluminum by mass, or an aluminum alloy with an aluminum purity of 97 wt% or more, and which has a thermal conductivity of 190 W / m·K or more, a thermal expansion coefficient of 8.3 ppm / K or less, and which can be brazed at temperatures of 570°C or more.

Description

[Technical Field]

[0001] The present invention relates to a silicon carbide aluminum composite material and a method for manufacturing the silicon carbide aluminum composite material, and more particularly to a composite material comprising a porous molded body formed from a silicon carbide mixed powder and having a silicon carbide volume fraction of 75% or more, and metal aluminum or an aluminum alloy having an aluminum content of 97% or more, and a manufacturing technique for the same. [Background technology]

[0002] Aluminum silicon carbide (AlSiC), which is produced by impregnating a porous silicon carbide molded body (preform) with molten aluminum, is known as a typical metal-ceramic composite material (MMC). For example, AlSiC containing 60-80 volume % silicon carbide and 20-40 volume % aluminum is used as a heat sink for power modules due to its low thermal expansion and high thermal conductivity (see Patent Document 1).

[0003] Furthermore, AlSiC is actively used in components requiring precise thermal control and high reliability, such as wafer stages (mounting tables) and film formation units of semiconductor manufacturing equipment, etching showerheads, lift pins, base plates for optical components, and exposure devices. Patent Document 2 describes how the use of AlSiC, a composite material, in wafer stages can reduce the difference in coefficient of linear thermal expansion (CTE) between the ceramic material constituting the ceramic substrate. Therefore, it is possible to prevent damage to the bond between the ceramic substrate and the cooling substrate due to thermal stress. Furthermore, it describes how, when the ceramic substrate is an alumina substrate, a composite material such as AlSiC, which has a coefficient of linear thermal expansion (CTE) close to that of alumina, is preferable for use in the cooling substrate.

[0004] Furthermore, electrostatic chucks used to hold substrates in semiconductor manufacturing equipment have traditionally been made by bonding an insulating layer of alumina to an aluminum substrate. These AlSiC substrates are generally plated with Ni and then soldered to aluminum, silicon nitride, or alumina substrates that have Si semiconductors mounted on them.

[0005] An electrostatic chuck generally has an electrode embedded in an insulating material such as alumina or aluminum nitride, and when a voltage is applied to the electrode, dielectric polarization is generated, and the wafer is fixed by utilizing the attraction force between the electrode and the wafer. For this reason, as described in Patent Documents 3 and 4, electrostatic chucks have been produced by soldering or spraying an insulating layer made of a material such as alumina onto a metal substrate such as aluminum.

[0006] In recent years, semiconductors such as silicon carbide (SiC) and gallium nitride (GaN) have begun to be used in power modules, and their surface temperatures can reach 200°C or higher during use. Furthermore, soldering has caused problems such as peeling of the bond between aluminum nitride (AlN) and silicon nitride (SiN) substrates on which semiconductors are mounted. Because soldering and brazing have different melting points, the method of choice depends on the heat-resistant temperature of the substrate. Soldering is often used below 450°C, while brazing is often used above 450°C. Brazing at temperatures above 570°C is sometimes referred to as high-temperature brazing. Since silver brazing is not possible with aluminum, brazing with aluminum brazing is required. Because the melting point of the aluminum brazing material used in this case is between 571°C and 605°C, brazing that can be performed at temperatures above 570°C is being investigated. Specifically, for example, aluminum brazing begins to melt at 562°C to 577°C, as shown in Fig. 16 of Non-Patent Document 1.

[0007] In electrostatic chucks used in semiconductor manufacturing processes, the aluminum (Al) substrate and alumina layer are typically bonded by thermally spraying alumina onto the aluminum substrate, as described in Patent Document 4. In recent years, electrostatic chucks have come to be used in CVD and etching equipment in semiconductor manufacturing processes, and operating temperatures have risen to 300°C or higher. However, due to the large difference in thermal expansion coefficients between the aluminum substrate and the alumina layer, peeling due to thermal expansion has become a problem. Patent Document 5 points out the problem of peeling and destruction due to the difference in thermal expansion with materials (such as alumina) used in semiconductor manufacturing equipment, and also points out that the coefficient of linear thermal expansion (CTE) should be controlled and adjusted through material design.

[0008] For the reasons mentioned above, the use of a substrate made of aluminum silicon carbide (AlSiC) composite material, which has a low thermal expansion coefficient close to that of alumina, as an alternative to aluminum substrates is being considered. However, Non-Patent Document 2 states that the mismatch in the thermal expansion coefficient (CTE) of different materials and the concentration of interfacial stress under repeated thermal cycles pose problems of debonding. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-57252 [Patent Document 2] Japanese Patent Application Publication No. 2023-109671 [Patent Document 3] Japanese Patent Application Laid-Open No. 2004-31938 [Patent Document 4] Patent No. 3172671 [Patent Document 5] Patent No. 5680664 [Non-patent literature]

[0010] [Non-Patent Document 1] UACJ Technical Reports Vol.4(2017),p.72 [Non-patent document 2] Micromachines(Basel).2024 Mar 11;15(3):376.doi:10.3390 / mi15030376 “Delamination of Plasticized Devices in Dynamic Service Environments” p.6 Summary of the Invention [Problem to be solved by the invention]

[0011] In contrast to the above-described conventional techniques, the inventors have found that, particularly in practical applications, the key issue is how to effectively bond a substrate made of a silicon-aluminum carbide composite material (sometimes referred to as an AlSiC composite material) to an alumina insulating layer. To develop the above-described bonding technology, a new AlSiC material is needed for the substrate, which, unlike conventional materials, does not melt at temperatures above 570°C. This is because, if the melting point of the Al alloy constituting the AlSiC substrate is lower than, for example, 570°C, the melting point of the aluminum brazing filler metal, the aluminum matrix will flow out of the AlSiC substrate before the bonding temperature reaches 570°C or higher and react with the higher-melting brazing filler metal, resulting in a lower melting point. Furthermore, softening of the substrate occurs, preventing the desired high-temperature bonding.

[0012] Therefore, there is a demand for an AlSiC material that has the same thermal conductivity and thermal expansion coefficient as conventional alumina, but also has the new property of being able to be brazed to semiconductor mounting components or insulating components such as alumina at temperatures of 570°C or higher using brazing filler metal instead of solder.

[0013] Therefore, an object of the present invention is to provide a silicon carbide aluminum composite material (AlSiC or SiC / Al alloy) having new properties, which is obtained by combining it with metallic aluminum or an aluminum alloy having a melting point of approximately 570°C or higher, which has a high silicon carbide content, a high thermal conductivity of 190 W / m K or higher, a thermal expansion coefficient of 8.3 ppm / K or lower, which is similar to that of alumina and does not significantly differ in thermal expansion, and which can be brazed at temperatures of 570°C or higher; and to develop a technique for easily producing an excellent silicon carbide aluminum composite material having the above properties. [Means for solving the problem]

[0014] The above object is achieved by the following silicon carbide aluminum composite material and method for producing the silicon carbide aluminum composite material. That is, the present invention provides the following silicon carbide aluminum composite material. In the present invention, the "average particle size" refers to the particle size (median diameter) at an integrated value of 50% in a particle size distribution determined by a laser diffraction / scattering method.

[0015] [1] A composite material comprising a porous molded body having a silicon carbide volume fraction of 75% or more, formed from a silicon carbide mixed powder obtained by mixing silicon carbide powder having an average particle size of 100 μm or more with one or more types of silicon carbide powder having an average particle size of 50 μm or less, and impregnated with metallic aluminum having a melting point of 570°C or more and containing less than 3 wt% impurities other than aluminum by mass, or an aluminum alloy having an aluminum purity of 97 wt% or more, the composite material having a thermal conductivity of 190 W / m·K or more, a thermal expansion coefficient of 8.3 ppm / K or less, and capable of being brazed at a temperature of 570°C or more.

[0016] Preferred embodiments of the silicon carbide aluminum composite material of the present invention include the following. [2] The silicon carbide aluminum composite material according to [1] above, wherein the aluminum alloy is at least one selected from the group consisting of 1000 series pure aluminum alloys having a purity of 99.00 wt% or more, in which the total amount of metals other than aluminum is less than 3 wt%, 3000 series aluminum alloys to which at least manganese is added, 5000 series aluminum alloys to which at least magnesium is added, and 6000 series aluminum alloys to which at least magnesium and silicon are added. [3] The silicon carbide aluminum composite material according to [2] above, wherein the 6000 series aluminum alloy is at least one selected from the group consisting of 6101, an aluminum alloy containing 0.5 wt% or less iron and 0.35 wt% to 0.8 wt% magnesium; 6063, an aluminum alloy containing 0.45 wt% to 0.9 wt% magnesium; and 6082, an aluminum alloy containing 0.7 wt% to 1.3 wt% silicon, 0.5 wt% or less iron, and 0.6 wt% to 1.2 wt% magnesium.

[0017] [4] The silicon carbide aluminum composite material according to any one of [1] to [3] above, wherein the porous molded body having a silicon carbide volume fraction of 75% or more further comprises at least one inorganic material or a fired product of an organic-inorganic material selected from the group consisting of colloidal silica, water glass, and ethyl silicate.

[0018] [5] The silicon carbide aluminum composite material according to any one of the above [1] to [4], which is used in a semiconductor manufacturing device. [6] The silicon carbide aluminum composite material according to any one of the above [1] to [4], which is used in an electrostatic chuck.

[0019] As another embodiment, the present invention provides the following method for producing a silicon carbide aluminum composite material. [7] A process of putting a silicon carbide mixed powder, which is a mixture of silicon carbide powder having an average particle size of 100 μm or more and at least one silicon carbide powder having an average particle size of 50 μm or less, water or an organic solvent, and at least one inorganic material or organic-inorganic material selected from the group consisting of colloidal silica, water glass, and ethyl silicate, into a container to form a slurry, and subjecting the slurry to sedimentation molding with vibration or slip casting molding with vibration to produce a solidified body, and firing the solidified body at 400°C to 1000°C to obtain a porous molded body having a silicon carbide volume fraction of 75% or more; A method for producing a silicon carbide aluminum composite material, comprising a high-pressure impregnation step of placing the porous molded body obtained in the above step, having a silicon carbide volume fraction of 75% or more, in a pressing die, melting metallic aluminum having a melting point of 570°C or higher and containing less than 3 wt% of impurities other than aluminum, or an aluminum alloy having an aluminum purity of 97 wt% or more, and high-pressure impregnation of the molded body with the molten metallic aluminum or aluminum alloy at 30 to 100 MPa to obtain a silicon carbide aluminum composite material.

[0020] Preferred embodiments of the method for producing a silicon carbide aluminum composite material of the present invention are as follows. [8] A method for producing a silicon carbide aluminum composite material according to item [7] above, in which the step of obtaining the porous molded body having a silicon carbide volume fraction of 75% or more comprises placing the container containing the slurry on a vibrator and vibrating the slurry to cause it to settle, then removing the supernatant liquid, freezing and solidifying the removed slurry, and then removing the frozen solidified body from the container and firing it at 400°C to 1000°C to obtain a porous molded body having a silicon carbide volume fraction of 75% or more. [9] A method for producing a silicon carbide aluminum composite material according to [7] or [8] above, wherein in the high pressure infiltration step for obtaining the silicon carbide aluminum composite material, a porous compact having a silicon carbide volume fraction of 75% or more is heated to 400°C to 1000°C, placed in a pressing mold heated to 250°C or higher, and the metal aluminum or metal aluminum alloy melted at a temperature of 700°C or higher is infiltrated under high pressure into the porous compact to form a composite. [Effects of the Invention]

[0021] The present invention as described above provides the following effects. The silicon carbide aluminum composite material of the present invention exhibits high thermal conductivity and a low coefficient of thermal expansion, enabling efficient thermal management in products to which it is applied, making it particularly suitable for applications requiring high reliability. Specifically, it can be suitably used as a manufacturing material for precision parts such as power semiconductors that require high reliability, such as insulated gate bipolar transistors (IGBTs) and diodes, and base plates and heat sinks for power modules.

[0022] Furthermore, because the silicon carbide aluminum composite material of the present invention exhibits little expansion or contraction due to temperature changes, internal stress in the materials that make up parts and devices is reduced, allowing high reliability to be maintained even over long periods of use. This is expected to extend the life of electrical, electronic, optical, and mechanical products, and reduce the frequency of maintenance. In particular, when the silicon carbide aluminum composite material of the preferred embodiment of the present invention is used as a manufacturing material for the above-mentioned precision parts, it exhibits the following excellent properties: (1) The high thermal conductivity and light weight achieved by using porous molded bodies with a silicon carbide volume fraction of 75% or more improve the performance, reliability, and stability of semiconductors. (2) It can also be applied to heat spreaders, heat dissipation lids, optical and communication related equipment, etc. (3) In power modules, brazing at high temperatures is possible, and for example, a substrate made of an AlSiC composite material and an alumina insulating layer can be joined well, allowing the product to operate stably even when used at high temperatures. (4) When the silicon carbide aluminum composite material of the preferred embodiment of the present invention is applied to the manufacturing of precision parts and the like, its high thermal conductivity and corrosion resistance enable efficient thermal management of the product, improve the cooling performance of power modules and high-output devices, and prevent product failure due to overheating. (5) Due to the above-mentioned advantages expected for various products by applying the silicon carbide aluminum composite material of the present invention, it can be used in heat exchangers for automobiles, vehicles, and transport equipment, and is also expected to be applied in various industries such as aerospace, electronics, etc. In particular, the silicon carbide aluminum composite material of a preferred embodiment of the present invention is suitable for use in high-temperature environments, and is therefore ideal as a manufacturing material for parts that require heat resistance. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a photograph showing the appearance of a 200 mm × 200 mm × 10 mm thick plate-shaped silicon carbide aluminum composite material prepared in Example 2 of the present invention, which has a volume fraction of silicon carbide of 76% and a volume fraction of aluminum alloy 6061 with an aluminum purity of 97% by mass or more of 24%, when heated to 570°C. [Figure 2] FIG. 10 is a photograph showing the appearance of a 200 mm × 200 mm × 10 mm thick plate-shaped silicon carbide aluminum composite material prepared in Comparative Example 5 of the present invention, which has a silicon carbide volume fraction of 77% and an aluminum alloy AC3C volume fraction of 24% containing 3 mass% or more of metal components other than aluminum, when heated to 570°C. [Figure 3] FIG. 1 is a photograph showing the difference in the surface state of the plate-shaped silicon carbide aluminum composite material prepared in Example 2 of the present invention shown in FIG. 1 (left side) and the plate-shaped silicon carbide aluminum composite material prepared in Comparative Example 5 of the present invention shown in FIG. 2 (right side) when heated to 630°C. [Figure 4] 2 shows a surface SEM image (left side) and an EDX analysis diagram (right side) of the plate-shaped silicon carbide aluminum composite material prepared in Example 2 of the present invention shown in FIG. 1. [Figure 5] 3 shows a surface SEM image (left side) and an EDX analysis diagram (right side) of the plate-shaped silicon carbide aluminum composite material prepared in Comparative Example 5 of the present invention shown in FIG. 2. [Figure 6]2 is a surface EDX analysis spectrum of the plate-shaped silicon carbide aluminum composite material prepared in Example 2 of the present invention shown in FIG. 1. [Figure 7] 3 is a surface EDX analysis spectrum of the plate-shaped silicon carbide aluminum composite material prepared in Comparative Example 5 of the present invention shown in FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0024] The present invention will be described in detail below with reference to preferred embodiments. The silicon carbide aluminum composite material of the present invention is a composite material exhibiting unprecedented properties, which is obtained by impregnating a porous molded body having a high silicon carbide volume fraction of 75% or more, formed from a silicon carbide mixed powder of a unique composition combining at least two types of powder, one with a large particle size and one with a fine particle size, with a molten aluminum metal or aluminum alloy containing 97 wt% or more of aluminum, with the amount of impurities or metal components other than aluminum controlled to less than 3 wt%. More specifically, the silicon carbide aluminum composite material of the present invention is a composite material obtained by impregnating a porous molded body (preform) having a silicon carbide volume fraction of 75% or more, which is formed from a silicon carbide mixed powder obtained by mixing silicon carbide powder having an average particle size of 100 μm or more with one or more types of silicon carbide powder having an average particle size of 50 μm or less, with metallic aluminum having a melting point of 570°C or more and containing less than 3 wt% impurities other than aluminum, or an aluminum alloy having an aluminum purity of 97 wt% or more, and which is characterized by having a thermal expansion coefficient of 8.3 ppm / K or less and being capable of being brazed at a temperature of 570°C or more.

[0025] The silicon carbide aluminum composite material of the present invention having the above-mentioned characteristics can be easily obtained by the following method for producing a silicon carbide aluminum composite material of the present invention. The production method of the present invention comprises placing a silicon carbide mixed powder, which is a mixture of silicon carbide powder having an average particle size of 100 μm or more and one or more silicon carbide powders having an average particle size of 50 μm or less, water or an organic solvent, and at least one inorganic material or organic-inorganic material selected from the group consisting of colloidal silica, water glass, and ethyl silicate, into a container to form a slurry, subjecting the slurry to sedimentation molding with vibration or slip casting with vibration to produce a solidified body, and firing the solidified body at 400°C to 1000°C to produce a porous material having a silicon carbide volume fraction of 75% or more. and a high-pressure impregnation step of placing the porous molded body obtained in the above step, which has a silicon carbide volume fraction of 75% or more, in a press die, melting metallic aluminum having a melting point of 570°C or higher and containing less than 3 wt% of impurities other than aluminum, or an aluminum alloy having an aluminum purity of 97 wt% or more, and high-pressure impregnation of the molded body with the molten metallic aluminum or aluminum alloy at 30 MPa to 100 MPa to obtain a silicon carbide aluminum composite material.

[0026] The raw materials constituting the silicon carbide aluminum composite material of the present invention will be described below. (Silicon carbide powder) The composite material of the present invention is characterized in that it uses a porous molded body (preform) having a silicon carbide volume fraction of 75% or more, and in particular that silicon carbide powder is selected from among ceramic powders as the material for forming the preform, and further that a silicon carbide mixed powder with a specific particle size composition is used. Specifically, it is characterized in that it uses a porous molded body (preform) having a silicon carbide volume fraction of 75% or more formed using a silicon carbide mixed powder obtained by mixing silicon carbide powder having an average particle size of 100 μm or more with one or more silicon carbide powders having an average particle size of 50 μm or less. The ratio of the silicon carbide powder having an average particle size of 100 μm or more to the one or more silicon carbide powders having an average particle size of 50 μm or less used in combination therewith is preferably, for example, silicon carbide powder having an average particle size of 100 μm or more:silicon carbide powder having an average particle size of 50 μm or less=1:7 to 1:1 on a volume basis. More preferably, the ratio of silicon carbide powder of 100 μm or more to silicon carbide powder of 50 μm or less is approximately 4:7 to 4:6. By using a mixed powder thus blended and uniformly mixed, a porous molded body having a silicon carbide volume fraction of 75% or more, as specified in the present invention, can be easily obtained. The "average particle size" of the silicon carbide powder in the present invention is the particle size (median diameter) at 50% of the integrated value in the particle size distribution determined by laser diffraction / scattering method.

[0027] The silicon carbide used in this invention has high hardness, excellent heat resistance, and durability, and is used as a polishing and grinding material and a fire-resistant material. Because of its excellent heat resistance, particularly at high temperatures, it has recently attracted attention as a semiconductor material and related materials. Silicon carbide is also known to be an excellent conductor of heat, with a high thermal conductivity of 120 to 270 W / m·K (for sintered bodies), a value almost comparable to that of metals. Furthermore, silicon carbide has the advantage of being resistant to changes in length and volume with increasing temperature, and its thermal expansion coefficient is 4.5×10 -6 / K, which is lower than that of metals, and combined with its thermal conductivity, it is known as a material that exhibits extremely high resistance to thermal shock. The silicon carbide powder having an average particle size of 100 μm or more and the silicon carbide powder having an average particle size of 50 μm or less used in the present invention are both readily available on the market. When mixing the silicon carbide powder having an average particle size of 100 μm or more with one or more silicon carbide powders having an average particle size of 50 μm or less, it is preferable to mix them uniformly using a conventional mixer.

[0028] (Preparation of porous compact with silicon carbide volume fraction of 75% or more) A porous molded body (preform) having a silicon carbide volume fraction of 75% or more constituting the silicon carbide aluminum composite material of the present invention can be easily obtained by fabricating it as follows using a silicon carbide mixed powder having the specific particle size configuration described above. Since the mixed powder specified in the present invention has poor packing properties when used as a powder, when obtaining a molded body by methods such as press molding, CIP molding, and precipitation, it is preferable to use water or an organic solvent, and if necessary, a binder, in combination with the silicon carbide mixed powder to form a slurry. The organic solvent is not particularly limited, but examples include ethanol, methanol, isopropyl alcohol, acetone, polyethylene glycol, and silicone-based organic solvents. The binder can be at least one inorganic or organic-inorganic material selected from the group consisting of colloidal silica, water glass, and ethyl silicate.

[0029] The amount of binder used is preferably in the range of 0.5% to 10% by mass based on the silicon carbide mixed powder. In order to further improve the moldability of the molded body (preform), an organic binder such as PVA or PVB may be added in addition to the inorganic binders listed above. The organic binder is burned off when the solidified body is fired, so it does not remain in the molded body (preform).

[0030] According to the inventors' investigations, the porous green body (preform) of the silicon carbide-aluminum composite material of the present invention, having a silicon carbide volume fraction of 75% or more, is preferably prepared by forming a slurry from a silicon carbide powder mixture as described above, followed by precipitation molding or slip casting with vibration to produce a solidified body, and then firing the resulting solidified body to produce a porous green body. The precipitation molding and slip casting methods described above are techniques primarily used in ceramic molding processes. Sedimentation molding is a method in which a slurry containing dispersed solid particles is poured into a container, and a high-density green body is formed in the lower layer as the particles settle due to gravity. Slip casting is a molding method in which a viscosity-adjusted slip (slip: a liquid in which solid powder is dispersed in water or a solvent) is poured into a porous mold, and the liquid components in contact with the mold wall are absorbed and filtered, forming a solid layer on the inner surface of the mold. In the manufacturing method of the present invention, it is essential to add "vibration" to each molding step in order to improve the uniformity of the slurry when the silicon carbide powder mixture is made into a slurry, to degas the slurry, to shorten the molding time, and to increase the molding density.

[0031] By producing a solidified body by the method of applying vibration to the slurry as described above, it is possible to easily and reliably obtain a porous molded body having a high silicon carbide volume fraction of 75% or more. Furthermore, as mentioned above, silicon carbide has excellent heat resistance, particularly at high temperatures, so the firing temperature can be as high as 400°C to 1000°C. This has the advantage that the temperature can be easily adjusted when firing a solidified body formed from a slurry containing the silicon carbide mixed powder specified in the present invention. According to the inventors' studies, by firing the solidified body at a temperature of, for example, about 600°C to 800°C, it is possible to stably obtain a porous molded body (preform) having a high silicon carbide volume fraction of 75% or more specified in the present invention.

[0032] In the process for producing a silicon carbide aluminum composite material of the present invention, in the step of obtaining a porous molded body having a silicon carbide volume fraction of 75% or more, a method for preparing a solidified body before firing as described below is also a preferred embodiment of the present invention. The mixed silicon carbide powder is made into a slurry as described above, the slurry is placed in a container made of silicone rubber or the like, the container is placed on a vibrator to vibrate the slurry for sedimentation, the supernatant liquid is removed, the removed slurry is frozen and solidified, and the resulting frozen solid is removed from the container and fired at a temperature of 400 to 1000°C, whereby a porous molded body having a silicon carbide volume fraction of 75% or more as specified in the present invention can be reliably obtained.

[0033] (Combination of porous molded body with metal aluminum or aluminum alloy) The silicon carbide aluminum composite material of the present invention can be prepared, for example, by a high-pressure impregnation process in which metallic aluminum having a melting point of 570°C or higher and containing less than 3 wt% of impurities other than aluminum, or an aluminum alloy having an aluminum purity of 97 wt% or higher, is dissolved in a porous molded body (preform) obtained as described above, having a silicon carbide volume fraction of 75% or higher, and the molten metallic aluminum or aluminum alloy is impregnated at a high pressure of 30 to 100 MPa to obtain a silicon carbide aluminum composite material.

[0034] The aluminum alloy used in the manufacturing method of the present invention described above can be at least one selected from the group consisting of 1000 series pure aluminum alloys with a purity of 99.00% or more, in which the total amount of metals other than aluminum is less than 3 wt%, 3000 series aluminum alloys with at least manganese added, 5000 series aluminum alloys with at least magnesium added, and 6000 series aluminum alloys with at least magnesium and silicon added.

[0035] According to the inventors' investigations, among the above-mentioned aluminum alloys, it is preferable to use 6000-series aluminum alloys containing at least magnesium and silicon. As 6000-series aluminum alloys that can be suitably used in the present invention, the total amount of metals other than aluminum must be less than 3 wt%. Examples of suitable 6000-series aluminum alloys include 6101, an aluminum alloy containing 0.5 wt% or less of iron and 0.35 wt% to 0.8 wt% of magnesium; 6063, an aluminum alloy containing 0.45 wt% to 0.9 wt% of magnesium; and 6082, an aluminum alloy containing 0.7 wt% to 1.3 wt% of silicon, 0.5 wt% to 0.5 wt% of iron, and 0.6 wt% to 1.2 wt% of magnesium. In addition to the aluminum alloys listed above, molten aluminum containing less than 3 wt% of impurities other than aluminum can also be used in the manufacturing method of the present invention. What is important in the present invention is that the molten metal that is to be high-pressure impregnated into a porous molded body having a silicon carbide volume fraction as high as 75% or more is a high-purity molten aluminum having an aluminum purity of 97 wt% or more, more preferably 98 wt% or more.

[0036] A conventional method can be used to high-pressure impregnate a porous molded body having a high silicon carbide volume fraction of 75% or more with metallic aluminum containing less than 3 wt% of impurities other than aluminum or an aluminum alloy having an aluminum purity of 97 wt% or more. Specifically, for example, a porous molded body having a silicon carbide volume fraction of 75% or more is heated to 400°C to 1000°C, placed in a press mold heated to 250°C or higher, and the metallic aluminum or aluminum alloy melted at 700°C or higher is high-pressure impregnated into the porous molded body at 30 MPa to 100 MPa to form a composite. According to the inventors' investigations, if a porous molded body having a silicon carbide volume fraction of 75% or more is high-pressure impregnated with molten aluminum without heating it to 400°C or higher, the molten aluminum rapidly cools and solidifies near the surface, which can result in the molten aluminum not fully penetrating the interior of the molded body. It has also been confirmed that the molten aluminum used for impregnation can be impregnated stably to the inside of the compact by using aluminum melted at 700°C or higher and performing high-pressure impregnation.

[0037] The silicon carbide aluminum composite material of the present invention is suitable for use in, for example, semiconductor manufacturing equipment and electrostatic chucks. In semiconductor devices, the use of AlSiC composite materials is particularly desired in wafer stages (mounting tables), film formation units, etching showerheads, lift pins, base plates for optical components, and exposure devices. However, it can also be used in any component requiring high thermal conductivity and low thermal expansion, and is not limited to this. Electrostatic chucks are widely used in semiconductor manufacturing equipment and components related to such equipment. However, electrostatic chucks are also used in industrial applications such as flat panel display manufacturing equipment, laser processing equipment, robot hands, precision coaters, printers, and optical component processing equipment, as well as in the medical and life science fields, such as microfluidic chips and cell observation. Electrostatic chucks are primarily suitable for applications requiring non-contact holding, precise positioning, and planarization, and specific applications are not limited to the specific examples listed above. [Example]

[0038] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0039] [Example 1] In this example, homogeneously mixed colloidal silica (48 wt% silicon oxide) was used as the binder. A silicon carbide mixed powder was prepared by uniformly mixing three types of silicon carbide powder with different particle sizes in a mixer to obtain the composition shown in Table 1. A silicone rubber container was filled with a slurry. Specifically, 4200 g of silicon carbide powder with an average particle size of 100 μm or more, 700 g of silicon carbide powder with an average particle size of 85 μm, and 2100 g of silicon carbide mixed powder containing one type of silicon carbide powder with an average particle size of 50 μm or less were added to the silicon carbide mixed powder with water and the colloidal silica. The container containing the slurry was placed on a vibrator and vibrated for 1 hour to settle the powder. The supernatant liquid was then removed from the container, and the mixture was frozen and solidified in a freezer for 10 hours. After freezing and solidifying, the solid was removed from the container. The solidified body was then taken out and fired at 700°C to obtain a silicon carbide molded body (preform) with a silicon carbide volume fraction of 77%.

[0040] The preform obtained above was heated to 600°C and placed in a press mold heated to 250°C. Aluminum alloy 6061 (aluminum purity 98.0%) was then melted at 730°C and cast into the mold, followed by high-pressure impregnation at 100 MPa. As a result, a silicon carbide composite material with a silicon carbide volume fraction of 77% was obtained.

[0041] The thermal expansion coefficient of the silicon carbide aluminum composite material of this example obtained as described above was 8.1 ppm / K. The thermal expansion coefficient was measured using a thermomechanical analyzer TMA-60 (trade name, manufactured by Shimadzu Corporation). Furthermore, when the heat resistance of the plate-shaped silicon carbide aluminum composite obtained as described above was examined, it was found that the aluminum alloy did not melt even after heating at 600°C, and a stainless steel rod with a diameter of 5 mm was heated at 1 to 5 kg / cm. 2 Even when pierced with a pressure of 1000 W, no puncture or deformation was observed. Furthermore, the thermal conductivity of the composite material obtained as described above was 195 W / m·K, which was a high value. It was also confirmed that brazing was possible at temperatures of 570°C or higher. Furthermore, brazing at temperatures of 600°C or higher was also possible. Table 1 summarizes the composition of the raw materials for the silicon carbide aluminum composite material of this example and the properties of the obtained silicon carbide aluminum composite material.

[0042] [Example 2] In this example, a silicon carbide aluminum composite material was produced under the same conditions as in Example 1, except that a slurry was used that was prepared containing a silicon carbide mixed powder obtained by uniformly mixing three types of silicon carbide powder having different particle sizes in a mixer to obtain the composition shown in Table 1. Specifically, a silicon carbide mixed powder containing 4900 g of silicon carbide powder having an average particle size of 100 μm or more and two types of silicon carbide powder having an average particle size of 50 μm or less, 1400 g of silicon carbide powder having an average particle size of 25 μm and 700 g of silicon carbide powder having an average particle size of 14 μm, was used.

[0043] As a result, a silicon carbide molded body (preform) with a silicon carbide volume fraction of 76% was obtained, and the molded body was impregnated with aluminum alloy 6061 (aluminum purity 98.0%) at high pressure to obtain the silicon carbide aluminum composite material of this example. When evaluated using the same method as in Example 1, the obtained composite material showed no adhesion or deformation due to the stainless steel rod even at 600°C. Figure 1 shows a photograph of the appearance of a plate-shaped composite material obtained in this example, with a silicon carbide volume fraction of 76% and an aluminum alloy 6061 volume fraction of 24%, after heating to 570°C. As shown in Figure 1, the surface condition of the silicon carbide aluminum composite material of this example remained almost unchanged from that at room temperature, and palpation with a stainless steel rod under the above-mentioned conditions confirmed that it maintained a strong state. The size of the plate of the composite material shown in Figure 1 is 200 mm x 200 mm x 10 mm thick.

[0044] The thermal expansion coefficient of the silicon carbide aluminum composite material of this example obtained as described above was 8.3 ppm / K. It was confirmed that brazing at temperatures above 570°C was possible, as well as at temperatures above approximately 600°C. Figure 3 is a photograph showing the surface appearance of a silicon carbide aluminum composite material of the size described above in this example when heated to 630°C, compared with that of the plate-shaped composite material of Comparative Example 5 described below. As shown in Figure 3, in the case of the plate-shaped composite material of Comparative Example 5 on the left side of Figure 3, which has a silicon carbide volume fraction of 77% and an aluminum alloy AC3C (components other than aluminum: 13.2%) volume fraction of 24%, the aluminum alloy precipitated in a dome shape on the surface of the plate, resulting in loss of flatness and making brazing impossible. This point will be discussed later. On the other hand, in the case of the plate-shaped composite material of Example 2, which has a silicon carbide volume fraction of 76% and an aluminum alloy 6061 (aluminum purity 98.0%) volume fraction of 24%, shown on the right side of Figure 3, almost no change was observed in the surface condition, and good brazing was possible. Table 1 shows the composition of the raw materials for the silicon carbide aluminum composite material of Example 2 and the properties of the obtained silicon carbide aluminum composite material.

[0045] Figure 4 shows the results of observing the surface of the silicon carbide aluminum composite material of this example using a scanning electron microscope. The left image in Figure 4 is an SEM image taken with a scanning electron microscope, and the right image in Figure 4 is a mapping image obtained by energy dispersive X-ray spectroscopy (product name: EDX VJE-0003) corresponding to the SEM image on the left. In the present invention, observation was performed using a Neo Scope JCM-7000 (product name) manufactured by JEOL Ltd. However, observation equipment and analysis equipment are not limited to this.

[0046] It can be seen from Figure 4 that the composite material of this example is a silicon carbide aluminum composite material containing silicon carbide particles with particle sizes of approximately 100 µm to 300 µm. Furthermore, the surface EDX analysis spectrum of the composite material of this example shown in Figure 6 reveals that the signal intensity (peak ratio) of the Al element relative to the Si element is small, at 30% or less. From this, it is believed that the reason why the composite material of this example showed little dissolution of metallic aluminum even at elevated temperatures of 600°C or higher, as shown in Figure 3, is because the silicon carbide and aluminum were sufficiently combined, allowing high hardness to be maintained even at high temperatures.

[0047] [Example 3] In this example, a silicon carbide aluminum composite material was produced under the same conditions as in Example 1, except that a slurry was used that was prepared containing a silicon carbide mixed powder obtained by uniformly mixing three types of silicon carbide powder having different particle sizes in a mixer to obtain the composition shown in Table 1. Specifically, a silicon carbide mixed powder containing 4200 g of silicon carbide powder having an average particle size of 100 μm or more and two types of silicon carbide powder having an average particle size of 50 μm or less, 1890 g of silicon carbide powder having an average particle size of 14 μm and 910 g of silicon carbide powder having an average particle size of 11.5 μm, was used.

[0048] As a result, a silicon carbide molded body (preform) with a silicon carbide volume fraction of 78% was obtained, and this molded body was impregnated with aluminum alloy 6061 (aluminum purity 98.0%) at high pressure to obtain the silicon carbide aluminum composite material of this example. When tested in the same manner as in Example 1, the composite material obtained in this example showed no adhesion or deformation due to the stainless steel rod even at 600°C. The silicon carbide aluminum composite material of this example obtained as described above had a thermal expansion coefficient of 8.0 ppm / K. It was also confirmed that brazing at temperatures above 570°C was possible, as well as at approximately 600°C. Table 1 summarizes the composition of the raw materials for the silicon carbide aluminum composite material of Example 3 and the properties of the resulting silicon carbide aluminum composite material.

[0049] TIFF0007814789000001.tif170170

[0050] [Comparative Example 1] In this comparative example, a silicon carbide aluminum composite material was produced under the same conditions as in Example 1, except that a slurry was used containing a silicon carbide mixed powder obtained by uniformly mixing two types of silicon carbide powder with different particle sizes in a mixer to obtain the composition shown in Table 2. Specifically, a silicon carbide mixed powder containing two types of silicon carbide powder with average particle sizes less than 100 μm was used, which contained 4900 g of silicon carbide powder with an average particle size of 85 μm and 2100 g of silicon carbide powder with an average particle size of 14 μm, and which did not contain silicon carbide powder with an average particle size of 100 μm or more. The volume fraction of silicon carbide in the resulting molded body was 70%.

[0051] A silicon carbide aluminum composite material of this comparative example was obtained by high-pressure impregnation of the same aluminum alloy 6061 (aluminum purity 98.0%) as used in Examples 1 to 3 into a molded body having a silicon carbide volume fraction of 70% as described above. Then, an evaluation test was carried out on the plate-shaped silicon carbide aluminum composite material of this comparative example using the same method as in Example 1. As a result, a stainless steel rod with a diameter of 5 mm was impregnated at a pressure of 1 to 5 kg / cm at a temperature of 570°C or higher. 2When the stainless steel rod was thrust with a pressure of 1000 kJ / cm2, the stainless steel rod adhered to the surface of the composite material and could only be pulled away by tension. The thermal expansion coefficient was 9.8 ppm / K. Furthermore, the silicon carbide aluminum composite material of this comparative example could not be brazed at temperatures above 570°C. Table 2 summarizes the composition of the raw materials for the silicon carbide aluminum composite material of this comparative example and the properties of the resulting silicon carbide aluminum composite material.

[0052] Comparative Example 2 In this comparative example, a silicon carbide aluminum composite material was produced under the same conditions as in Example 1, except that a slurry was used containing a silicon carbide mixed powder obtained by uniformly mixing three types of silicon carbide powder with different particle sizes in a mixer to obtain the composition shown in Table 2. Specifically, a silicon carbide mixed powder containing three types of silicon carbide powder with an average particle size of less than 100 μm was used, which contained 5600 g of silicon carbide powder with an average particle size of 85 μm, 700 g of silicon carbide powder with an average particle size of 14 μm, and 700 g of silicon carbide powder with an average particle size of 11.5 μm, and which did not contain silicon carbide powder with an average particle size of 100 μm or more. First, the volume fraction of silicon carbide in the obtained compact was 71%, and a compact with a low silicon carbide volume fraction was obtained, which was below the volume fraction of 75% or more specified in the present invention.

[0053] A silicon carbide aluminum composite material of this comparative example was obtained by high-pressure impregnation of a molded body having a silicon carbide volume fraction of 71% with the same aluminum alloy 6061 (aluminum purity 98.0%) as used in Examples 1 to 3. Then, an evaluation test was carried out on the plate-shaped silicon carbide aluminum composite material of this comparative example using the same method as in Example 1. As a result, a stainless steel rod with a diameter of 5 mm was impregnated at a pressure of 1 to 5 kg / cm at a temperature of 570°C or higher. 2 When the stainless steel rod was thrust with a pressure of 1000 kJ / cm2, it adhered to the surface of the composite material and could only be separated by pulling. The thermal expansion coefficient was 9.7 ppm / K. However, brazing at temperatures above 570°C was not possible. Table 2 shows the composition of the raw materials for the silicon carbide aluminum composite material of this comparative example and the properties of the resulting silicon carbide aluminum composite material.

[0054] Comparative Example 3 In this comparative example, a silicon carbide aluminum composite material was produced under the same conditions as in Example 1, except that a slurry prepared from silicon carbide powder containing only 7000 g of silicon carbide powder having an average particle size of 190 μm was used without using a mixed powder, as shown in Table 2. First, the volume fraction of silicon carbide in the obtained compact was 72%, and a compact with a low silicon carbide volume fraction was obtained, which was below the volume fraction of 75% or more specified in the present invention.

[0055] A silicon carbide aluminum composite material of this comparative example was obtained by high-pressure impregnation of the same aluminum alloy 6061 (aluminum purity 98.0%) used in Examples 1 to 3 into a molded body having the above-described silicon carbide volume fraction of 72%. The plate-shaped silicon carbide aluminum composite material of this comparative example was then evaluated using the same method as in Example 1. The results showed that at temperatures above 570°C, the stainless steel rod adhered to the surface of the composite material and could only be separated by pulling. The thermal expansion coefficient was 9.8 ppm / K. However, brazing at temperatures above 570°C was not possible. Table 2 summarizes the composition of the raw materials for the silicon carbide aluminum composite material of this comparative example and the properties of the resulting silicon carbide aluminum composite material.

[0056] Comparative Example 4 In this comparative example, a silicon carbide aluminum composite material was produced under the same conditions as in Example 1, except that a slurry prepared from silicon carbide powder containing only 7000 g of silicon carbide powder having an average particle size of 145 μm was used without using a mixed powder, as shown in Table 2. First, the volume fraction of silicon carbide in the obtained compact was 69%, and a compact with a low silicon carbide volume fraction was obtained, which was far below the volume fraction of 75% or more specified in the present invention.

[0057] A silicon carbide aluminum composite material of this comparative example was obtained by high-pressure impregnation of a molded body having a silicon carbide volume fraction of 69% as described above with the same aluminum alloy 6061 (aluminum purity 98.0%) as used in Examples 1 to 3. The plate-shaped silicon carbide aluminum composite material of this comparative example was then evaluated using the same method as in Example 1. The results showed that at temperatures above 570°C, the stainless steel rod adhered to the surface of the composite material and could only be separated by pulling. The thermal expansion coefficient was 10.3 ppm / K. However, brazing at temperatures above 570°C was not possible. Table 2 summarizes the composition of the raw materials for the silicon carbide aluminum composite material of this comparative example and the properties of the resulting silicon carbide aluminum composite material.

[0058] TIFF0007814789000002.tif168170

[0059] Comparative Example 5 In this comparative example, as shown in Table 3, a porous compact having a silicon carbide volume fraction of 77% was obtained using a slurry prepared containing a silicon carbide mixed powder obtained by uniformly mixing three types of silicon carbide powder with different particle sizes in advance in a mixer, similar to that used in Example 1. The obtained porous compact was then high-pressure impregnated with molten aluminum alloy AC3A under the same conditions as in Example 1, except that aluminum alloy AC3A containing at least 11 wt% silicon was used, to obtain a silicon carbide aluminum composite material of this comparative example. The volume fraction of silicon carbide in this silicon carbide aluminum composite material was 77%.

[0060] The silicon carbide-aluminum composite plate material of this comparative example obtained as described above was evaluated in the same manner as in Example 1. Figure 2 is a photograph showing the appearance of the silicon carbide-aluminum composite plate material prepared in this comparative example, which was impregnated with a 77% silicon carbide compact and had a 24% volume fraction of aluminum alloy AC3C containing 3% or more by mass of metal components other than aluminum. The material was heated to 570°C. As shown in Figure 2, spherical (round) blowouts of the aluminum alloy occurred at temperatures above 550°C. Round oozing of the aluminum alloy was also observed, and palpation with the stainless steel rod confirmed that the surface had softened. Furthermore, as shown in Figure 3, the blown aluminum alloy expanded significantly at temperatures above 600°C, resulting in dome-shaped deposition of the aluminum alloy on the surface, resulting in loss of flatness and making brazing impossible. Furthermore, the molten aluminum alloy adhered to the surrounding area. The thermal expansion coefficient was unmeasurable. Furthermore, brazing at temperatures above 570°C was not possible.

[0061] FIG. 5 shows the results of observation of the surface condition of the plate-shaped silicon carbide aluminum composite material of this comparative example obtained above using a scanning electron microscope. In FIG. 5, the left image is an SEM image obtained using a scanning electron microscope, and the right image is a mapping image obtained by energy dispersive X-ray spectroscopy (EDX VJE-0003) corresponding to the SEM image on the left. In the present invention, observation was performed using a NeoScope JCM-7000 (product name) manufactured by JEOL Ltd., but the apparatus is not limited to this. Comparing FIG. 5 for the plate-shaped silicon carbide aluminum composite material of this comparative example with the composite material of Example 1 shown in FIG. 4, it was confirmed that a silicon carbide aluminum composite material with a particle size of approximately 20 μm to 100 μm was formed, but that many particles had smaller particle sizes than in Example 2, and that many portions remained in the aluminum and silicon carbide state without being composited. Furthermore, when compared with the surface photograph after heating to 570°C in Fig. 2, when the temperature of the plate-shaped composite material produced in this comparative example was raised to 600°C or higher, there was a large amount of spherical and dome-shaped aluminum precipitates, as shown in Fig. 3. As described above, this aluminum precipitation phenomenon is presumed to have occurred because the content of aluminum not bonded to silicon carbide was higher in the plate-shaped composite material produced in this comparative example compared to Example 2, resulting in a decrease in the melting point of the composite material as a whole.

[0062] In the composite material of this comparative example, a comparison of the surface EDX analysis spectrum of the composite material of Example 1 shown in FIG. 6 with the surface EDX analysis spectrum of the composite material of Comparative Example 5 shown in FIG. 7 confirms that the signal intensity (peak ratio) of Al element relative to Si element is increased to 65% or more. This analysis result also shows that a larger amount of aluminum is precipitated on the surface of the composite material of this comparative example. In other words, it can be confirmed that the composite material of this comparative example, unlike the composite material of Example 2, is not suitable for use at high temperatures of 570°C or higher. Table 3 summarizes the composition of the raw materials for the silicon carbide aluminum composite material of this comparative example and the properties of the resulting silicon carbide aluminum composite material.

[0063] Comparative Example 6 In this comparative example, the composite material of this comparative example was produced under the same conditions as in Example 1, except that AC4C, an Al alloy containing 6.5 wt % silicon, was used, and an evaluation test similar to that carried out in Example 1 was carried out. A molded body having a silicon carbide volume fraction of 77% was obtained as in Comparative Example 5, and this molded body was impregnated with molten AC4C at high pressure to produce the silicon carbide aluminum composite material of this comparative example.

[0064] When heated at temperatures above 550°C, the aluminum alloy blew out in the form of balls. When heated at temperatures above 600°C, the blew aluminum alloy expanded significantly, and the molten aluminum adhered to the surrounding area. The thermal expansion coefficient was also unmeasurable. It was confirmed that brazing was not possible at temperatures above 570°C. Table 3 summarizes the composition of the raw materials for the silicon carbide aluminum composite material of this comparative example and the properties of the resulting silicon carbide aluminum composite material.

[0065] Comparative Example 7 In this comparative example, a silicon carbide mixed powder having the same composition as the molded body (preform) obtained in Example 2 described above was used, and a slurry similar to that prepared in Example 1 was used to produce a molded body (preform). In this comparative example, the slurry placed in a container was not vibrated, and a solidified body was formed by press molding. A molded body (preform) with a low silicon carbide volume fraction of 67.6% was obtained. The same aluminum alloy 6061 as used in Example 1 was then used under the same conditions as in Example 1, and the molded body with a low silicon carbide volume fraction of 67.6% was impregnated with molten aluminum alloy 6061 under high pressure to produce the composite material of this comparative example. Evaluation tests were conducted on the obtained composite material of this comparative example, and it was confirmed that there was no aluminum melting even when heated at temperatures above 600°C. Although the silicon carbide volume fraction was low at 67.6%, its thermal expansion coefficient was 10.06, which was higher than that of any of Examples 1 to 3 and Comparative Examples 1 to 3. Table 3 shows the composition of the raw materials for the silicon carbide aluminum composite material of this comparative example, and the properties of the resulting silicon carbide aluminum composite material.

[0066] TIFF0007814789000003.tif160170 [Industrial Applicability]

[0067] The silicon carbide aluminum (SiC / Al) composite material provided by this invention combines excellent thermal conductivity with a low coefficient of thermal expansion. In addition, it functions stably as a heat dissipation material even in high-temperature environments above 570°C, making it expected to be used in a variety of industrial fields. First, in the power electronics field, it can be used as a lightweight, thermal fatigue-resistant alternative to copper and molybdenum for packaging insulated gate bipolar transistors (IGBTs) and SiC power devices. The silicon carbide aluminum (SiC / Al) composite material provided by this invention is expected to extend the life and improve the reliability of various products. Furthermore, the silicon carbide aluminum (SiC / Al) composite material provided by this invention is compatible with high-temperature processes, and by being able to withstand 570°C-class packaging processes such as solder reflow and vacuum heat treatment, it is expected to enable the integrated packaging of next-generation high-power GaN and SiC devices. Furthermore, the silicon carbide aluminum (SiC / Al) composite material provided by this invention is lightweight and has excellent dimensional stability, so it is expected to be applied to aerospace equipment, automotive inverters, renewable energy equipment, and other power fields, contributing to product miniaturization and improved cooling efficiency. It is also expected to be developed into hybrid structures with copper and aluminum.

Claims

1. A composite material comprising a porous molded body having a silicon carbide volume fraction of 75% or more, the porous molded body being formed from a silicon carbide mixed powder containing silicon carbide powder having an average particle size of 100 μm or more and at least one type of silicon carbide powder having an average particle size of 50 μm or less, and impregnated with any one selected from the group consisting of 6101, 6063, 6082 and 6061, a 6000 series aluminum alloy having a melting point of 570°C or more and an aluminum purity of 97 wt% or more to which at least magnesium and silicon (silicon) have been added, the composite material having a thermal conductivity of 190 W / m·K or more, a thermal expansion coefficient of 8.3 ppm / K or less, and being capable of being brazed at a temperature of 570°C or more.

2. 2. The silicon carbide aluminum composite material according to claim 1, wherein the porous molded body having a volume fraction of silicon carbide of 75% or more further comprises a fired product of at least one inorganic material or organic-inorganic material selected from the group consisting of colloidal silica, water glass, and ethyl silicate.

3. 3. The silicon carbide aluminum composite material according to claim 1, which is used in semiconductor manufacturing equipment.

4. 3. The silicon carbide aluminum composite material according to claim 1, which is used in an electrostatic chuck.

5. a step of putting a silicon carbide powder mixture containing silicon carbide powder having an average particle size of 100 μm or more, at least one type of silicon carbide powder having an average particle size of 50 μm or less, water or an organic solvent, and at least one type of inorganic material or organic-inorganic material selected from the group consisting of colloidal silica, water glass, and ethyl silicate into a container to form a slurry, placing the container containing the slurry on a vibrator to vibrate the slurry and subject it to a settling treatment, then removing the supernatant liquid, freezing and solidifying the removed slurry, removing the resulting frozen solid from the container, and firing the solid at 400°C to 1000°C to obtain a porous molded body having a silicon carbide volume fraction of 75% or more; A method for producing a silicon carbide aluminum composite material, comprising: a high-pressure impregnation step of placing the porous molded body obtained in the above step, having a silicon carbide volume fraction of 75% or more, in a mold; melting a 6000 series aluminum alloy selected from the group consisting of 6101, 6063, 6082, and 6061, which has a melting point of 570°C or more and an aluminum purity of 97 wt% or more to which at least magnesium and silicon (silicon) have been added; and high-pressure impregnation of the molded body with the molten aluminum alloy at 30 to 100 MPa, thereby obtaining a silicon carbide aluminum composite material having a thermal conductivity of 190 W / m K or more, a thermal expansion coefficient of 8.3 ppm / K or less, and which can be brazed at a temperature of 570°C or more.

6. 6. The method for producing a silicon carbide aluminum composite material according to claim 5, wherein in the high-pressure impregnation step of obtaining the silicon carbide aluminum composite material, the porous compact having a silicon carbide volume fraction of 75% or more is heated to 400°C to 1000°C, placed in the mold heated to 250°C or higher, and the aluminum alloy melted at a temperature of 700°C or higher is high-pressure impregnated into the porous compact to form a composite.

7. 7. The method for producing a silicon carbide aluminum composite material according to claim 5, wherein the silicon carbide aluminum composite material is used in semiconductor manufacturing equipment.

8. 7. The method for producing a silicon carbide aluminum composite material according to claim 5, wherein the silicon carbide aluminum composite material is used for an electrostatic chuck.

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