Ceramic structure and heat exchanger

Abstract

A ceramic structure according to an aspect of an embodiment of the present invention comprises a substrate, a wiring conductor, and an intermediate body. The substrate contains silicon carbide as a main component. The wiring conductor is positioned on the substrate so as to sandwich a region in which the wiring conductor and the substrate are electrically isolated from each other. The intermediate body is positioned in at least a portion of the region in which the substrate and the wiring conductor are electrically isolated, has a volume resistivity that is higher than the volume resistivity of the substrate and the volume resistivity of the wiring conductor, and contains inorganic crystal particles as a main component.

Description

Ceramic structure and heat exchanger

[0001] The present disclosure relates to ceramic structures and heat exchangers.

[0002] For example, a heating member has been proposed in which a bonding layer made of glass or the like is disposed between a ceramic sintered body containing silicon carbide as a main component and wiring (see Patent Document 1).

[0003] Patent No. 5562086

[0004] A ceramic structure according to one aspect of the embodiment includes a substrate, a wiring conductor, and an intermediate body. The substrate contains silicon carbide as a primary component. The wiring conductor is located on the substrate across a region that electrically isolates the wiring conductor from the substrate. The intermediate body is located in at least a portion of the region that electrically isolates the substrate from the wiring conductor, has a volume resistivity higher than that of the substrate and that of the wiring conductor, and contains inorganic crystalline particles as a primary component.

[0005] FIG. 1 is a cross-sectional view schematically showing a ceramic structure according to a first embodiment. FIG. 2 is a cross-sectional view schematically showing a ceramic structure according to a second embodiment. FIG. 3 is a cross-sectional view schematically showing a ceramic structure according to a third embodiment. FIG. 4 is a cross-sectional view schematically showing a ceramic structure according to a fourth embodiment. FIG. 5 is a cross-sectional view schematically showing a ceramic structure according to a fifth embodiment. FIG. 6A is a plan view schematically showing a ceramic structure according to a sixth embodiment. FIG. 6B is a cross-sectional view schematically showing a ceramic structure according to the sixth embodiment. FIG. 7A is a plan view schematically showing a ceramic structure according to a seventh embodiment. FIG. 7B is a cross-sectional view schematically showing a ceramic structure according to the seventh embodiment. FIG. 8 is a cross-sectional view schematically showing a ceramic structure according to an eighth embodiment. FIG. 9A is a cross-sectional view schematically showing a ceramic structure according to a ninth embodiment. FIG. 9B is a cross-sectional view schematically showing a ceramic structure according to the ninth embodiment.

[0006] Hereinafter, embodiments of the ceramic structure and heat exchanger disclosed herein will be described with reference to the accompanying drawings. Note that the present disclosure is not limited to the embodiments shown below. It should be noted that the drawings are schematic, and the dimensional relationships and ratios of elements may differ from reality. Furthermore, the drawings may include portions where the dimensional relationships and ratios differ from one another.

[0007] Furthermore, in the following embodiments, expressions such as "constant," "orthogonal," "perpendicular," or "parallel" may be used, but these expressions do not necessarily mean "constant," "orthogonal," "perpendicular," or "parallel" in the strict sense. In other words, the above expressions allow for deviations due to, for example, manufacturing precision, installation precision, etc.

[0008] In conventional technology, the thermal conductivity of glass is lower than that of silicon carbide, so there is room for further improvement in thermal conductivity when silicon carbide is used as the main component of a ceramic sintered body. The above-mentioned problem can also occur when the bonding layer is made of a material other than glass. Specifically, the above-mentioned problem can occur when a ceramic sintered body mainly composed of silicon carbide is bonded to wiring via a bonding layer made of a material with a lower thermal conductivity than silicon carbide.

[0009] Embodiments of the present disclosure provide ceramic structures and heat exchangers that can improve heat transfer.

[0010] <First Embodiment> A ceramic structure according to a first embodiment will be described. Fig. 1 is a cross-sectional view schematically showing the ceramic structure according to the first embodiment. As shown in Fig. 1, the ceramic structure 1 includes a base 10, a wiring conductor 20, and an intermediate body 30.

[0011] The base 10 may have a disk shape with thicknesses at the top and bottom. However, the base 10 is not limited to this, and may have other shapes, such as a rectangular shape with thicknesses at the top and bottom. The base 10 contains silicon carbide (SiC) as a main component. In the present disclosure, a main component is, for example, a material that accounts for 50 mass% or more of the material. Silicon carbide is excellent in thermal conductivity, heat resistance, chemical resistance, hardness, etc. For example, the thermal conductivity of silicon carbide at 20°C is approximately 200 [W / (m·K)]. In contrast, the thermal conductivity of aluminum oxide (Al ２ O ３ The thermal conductivity of yttrium oxide (Y: alumina) is approximately 30 [W / (m·K)]. ２ O ３ The thermal conductivity of zirconium oxide (ZrO: yttria) is approximately 14 [W / (m·K)]. ２ The thermal conductivity of silicon carbide (zirconia) is approximately 3 W / (m·K). The thermal conductivity of aluminum nitride (AlN) is approximately 150 W / (m·K). Therefore, when the substrate 10 contains silicon carbide as a main component, it conducts heat more easily than when it contains a ceramic such as aluminum oxide as a main component. Therefore, the ceramic structure 1 of the present disclosure may be used in a heat exchanger.

[0012] Silicon carbide is a ceramic material that has excellent heat resistance and does not lose strength at high temperatures. This allows the production of ceramic structure 1 having substrate 10 with excellent strength. Substrate 10 contains silicon carbide as a main component and may further contain aluminum oxide, yttrium oxide, zirconium oxide, or aluminum nitride.

[0013] Furthermore, silicon carbide is a material that is chemically and physically stable and has high heat resistance, chemical resistance, and hardness among ceramics. For example, the hardness (Vickers hardness) of silicon carbide is approximately 23 GPa. In comparison, the hardness of aluminum oxide is approximately 15 GPa, the hardness of yttrium oxide is approximately 6 GPa, and the hardness of zirconium oxide is approximately 13 GPa. Furthermore, the hardness of aluminum nitride is approximately 11 GPa.

[0014] Therefore, the substrate 10 containing silicon carbide as a primary component has excellent heat resistance and chemical resistance and can withstand changes in the external environment. For example, as illustrated in FIG. 1 , flow paths 101 and 102 may be located within the substrate 10. Various fluids, such as liquids or gases that require high-temperature heating or corrosive chemicals, may flow through the flow paths 101 and 102. Metallic flow path members may dissolve depending on the properties of the fluids flowing through the flow paths. In contrast, by using silicon carbide as the primary component of the substrate 10, the chemical resistance of silicon carbide prevents the substrate 10 from dissolving even when fluids such as acids or chemicals are flowed through the flow paths 101 and 102. Therefore, heat exchange within the substrate 10 can be performed while maintaining high purity of the fluids, such as acids or chemicals, used in heat exchange. The width of the flow paths 101 and 102 may be, for example, 0.5 mm or more and 15 mm or less. The height of the flow channels 101, 102 may be 0.3 mm or more and 15 mm or less. The width and height of the flow channels may be outside the above ranges. The width of the wiring conductor 20 may be, for example, 5 μm or more and 200 mm or less. The thickness of the wiring conductor 20 may be, for example, 20 μm or more and 100 μm or less. The width and height of the wiring conductor 20 may be outside the above ranges. The width of the base 10 may be, for example, 50 mm or more and 600 mm or less. The thickness of the base 10 may be, for example, 4 mm or more and 50 mm or less. The width and height of the base 10 may be outside the above ranges. The width of the intermediate body 30 may be, for example, 5 mm or more and 600 mm or less. The thickness of the intermediate body 30 may be, for example, 20 μm or more and 10 mm or less. The width and height of the intermediate body 30 may be outside the above ranges.

[0015] However, the fluid flowing through the flow paths 101 and 102 is not limited to this, and any heat exchange medium capable of performing heat exchange within the base 10 may be used. The heat exchange medium may be a liquid such as water, or a gas such as an inert gas. The flow paths 101 and 102 may be located above and below the wiring conductor 20. This allows heat from the wiring conductor 20 to be transferred to the flow paths 101 and 102, thereby promoting heat exchange. However, the flow paths may be located either above or below the wiring conductor 20. The flow paths may also be located to the side of the wiring conductor 20.

[0016] The wiring conductor 20 is located on the base 10. For example, the wiring conductor 20 may be located inside the base 10. Silicon carbide has conductive or semi-conductive properties, and is conductive or semi-conductive. Therefore, in order to block conduction between the base 10 and the wiring conductor 20, a region A that electrically isolates the base 10 and the wiring conductor 20 is provided between the base 10 and the wiring conductor 20. For example, as shown in FIG. 1 , the region A that electrically isolates the base 10 and the wiring conductor 20 may be filled with an intermediate body 30. The base 10 and the wiring conductor 20 may be in contact with each other via the intermediate body 30. In other words, the periphery of the wiring conductor 20 may be covered by the intermediate body 30. The periphery of the intermediate body 30 may then be covered by the base 10. In the illustrated example, the wiring conductor 20 and the intermediate body 30 are located on the center side in the thickness direction of the base 10, but this is not limiting, and they may be located above the flow path 101, below the flow path 102, or to the side of these flow paths. This allows the heat of the wiring conductor 20 to be transferred to the flow path 101 or the flow path 102 side, thereby facilitating heat exchange.

[0017] The intermediate body 30 has a volume resistivity higher than that of the base body 10 and that of the wiring conductor 20. This allows the insulating intermediate body 30 to be interposed between the base body 10 and the wiring conductor 20. This allows the base body 10 and the wiring conductor 20 to be electrically isolated from each other. For example, the volume resistivity of silicon carbide at 20°C is about 10 ８When the wiring conductor 20 is made of tungsten or molybdenum, the volume resistivity of tungsten or molybdenum at 0°C is about 5 Ω cm. Therefore, a material having a volume resistivity higher than that of the base 10 and the wiring conductor 20 is a material having a volume resistivity of about 10 Ω cm, which represents the volume resistivity of silicon carbide, the main component of the base 10. ８ A material having a volume resistivity higher than [Ω·cm] may be used as a guide.

[0018] For example, the volume resistivity of aluminum oxide at 20°C is about 10 １４ The volume resistivity of yttrium oxide at 20°C is about 10 １３ The volume resistivity of zirconium oxide and aluminum nitride at 20°C is approximately 10 １４ The volume resistivity of these materials is 10 [Ω cm], which is the volume resistivity of silicon carbide. ８ [Ω cm]. Therefore, the material of the intermediate body 30 may contain, as a main component, any of aluminum oxide, yttrium oxide, zirconium oxide, and aluminum nitride, which have a higher volume resistivity than silicon carbide. However, the material of the intermediate body 30 is not limited to these, and any material may be contained as a main component as long as the volume resistivity is higher than the volume resistivity of the base body 10 and the volume resistivity of the wiring conductor 20.

[0019] The intermediate 30 contains inorganic crystalline particles as a main component. In other words, the intermediate 30 has a long-period structure like a crystal. On the other hand, glass does not have a long-period structure like a crystal. Therefore, the intermediate 30 does not contain glass as a main component. The inorganic crystalline particles may contain yttrium oxide or zirconium oxide as a main component. The inorganic crystalline particles may also contain aluminum nitride as a main component.

[0020] Silicon carbide, yttrium oxide, zirconium oxide, and aluminum nitride are materials that are difficult to sinter. The substrate 10 primarily composed of silicon carbide and the intermediate body 30 primarily composed of yttrium oxide, zirconium oxide, or aluminum nitride are sintered at high temperatures, for example, around 2000°C, to densify them. To achieve sintering at such high temperatures, the wiring conductor 20 is preferably made of tungsten (W) or molybdenum (Mo). These materials have high melting points, allowing the wiring conductor 20 to be integrally sintered with the substrate 10 and the intermediate body 30. In particular, yttrium oxide or zirconium oxide is an oxide, and the intermediate body 30 primarily composed of an oxide is more chemically stable than the intermediate body 30 primarily composed of a nitride, such as aluminum nitride. Therefore, yttrium oxide or zirconium oxide is easier to use than aluminum nitride and is also more easily applicable to co-firing with the substrate 10.

[0021] The intermediate body 30 may contain silicon carbide. In this case, the mass of silicon carbide relative to the total mass of the intermediate body 30 containing silicon carbide may be 1 mass% or less. In other words, when silicon carbide is added to the intermediate body 30, the mass of the intermediate body 30 relative to the total mass of the intermediate body 30 may be 99 mass% or more. By including silicon carbide in the intermediate body 30, the bonding strength between the base and the intermediate body can be improved. Furthermore, by setting the mass of silicon carbide relative to the total mass of the intermediate body 30 to 1 mass% or less, the insulating properties of the intermediate body 30, which is mainly composed of inorganic crystalline particles, can be ensured. This ensures insulation between the wiring conductor 20 and the base body 10 via the intermediate body 30. The intermediate body 30 may be a dense body or a porous body.

[0022] As shown in the illustrated example, two wiring conductors 20 or a ring-shaped wiring conductor 20 may be embedded near the center in the thickness direction of the base 10, and the periphery of the wiring conductor 20 may be covered with an insulating intermediate body 30. That is, the intermediate body 30 may be cylindrical and surround the wiring conductor 20. In the illustrated example, the intermediate body 30 is located in the entire region A that electrically isolates the base 10 and the wiring conductor 20. However, this is not limited thereto, and the intermediate body 30 may be located in at least a part of the region A that electrically isolates the base 10 and the wiring conductor 20. At least a part of the wiring conductor 20 may be in contact with the base 10 via the intermediate body 30. For example, the intermediate body 30 may be located in a part of the region A that electrically isolates the base 10 and the wiring conductor 20. A part of the wiring conductor 20 may be in contact with the base 10 via the intermediate body 30. Of the region A electrically isolating the base 10 and the wiring conductor 20, the region A where the intermediate body 30 is not located may be, for example, a cavity, as will be described later with reference to FIG.

[0023] The wiring conductor 20 may be a wiring for supplying power. The ceramic structure 1 may function as, for example, a wiring substrate that supplies necessary power to a power supply target such as an IC (Integrated Circuit). The wiring conductor 20 may be, for example, a heating resistor such as a heater. The ceramic structure 1 may function as, for example, a heating member.

[0024] For example, the thermal conductivity of glass at 20°C is approximately 1 W / (m·K). In contrast, the thermal conductivity of yttrium oxide is approximately 14 W / (m·K), the thermal conductivity of zirconium oxide is approximately 3 W / (m·K), and the thermal conductivity of aluminum nitride is approximately 150 W / (m·K). Therefore, the thermal conductivity of glass is lower than that of yttrium oxide, zirconium oxide, and aluminum nitride. Therefore, when glass is contained as the primary component of the intermediate body 30, heat generated from the wiring conductor 20 is less likely to transfer to the base 10 via the intermediate body 30 than when yttrium oxide, zirconium oxide, or aluminum nitride is contained as the primary component of the intermediate body 30. Therefore, when glass is contained as the primary component of the intermediate body 30, it is difficult to fully utilize the functionality of the base 10, which has high thermal conductivity, even if silicon carbide, which has good thermal conductivity, is contained as the primary component of the base 10. Furthermore, glass has inferior heat resistance compared to yttrium oxide, zirconium oxide, or aluminum nitride. Therefore, in the present disclosure, the intermediate 30 does not contain glass as a main component, but contains inorganic crystalline particles as a main component. The inorganic crystalline particles may be primarily composed of yttrium oxide or zirconium oxide. This allows heat generated in the wiring conductor 20 to be quickly transferred to the base 10 via the intermediate 30, thereby providing a ceramic structure 1 with high heat resistance.

[0025] The ceramic structure 1 can function as a temperature control member that controls the temperature of the base 10 by flowing a temperature-controlled heat exchange medium through the flow channels 101 and 102. For example, the ceramic structure 1 can function as a cooling member that cools the base 10 by flowing cooling water through the flow channels 101 and 102. Furthermore, the ceramic structure 1 can function as a heating member that heats the base 10 by flowing heated water through the flow channels 101 and 102. The flow channels 101 and 102 are an example of a first flow channel located inside the base 10.

[0026] Effect of First Embodiment In the ceramic structure 1 according to the first embodiment, heat exchange can be promoted by including silicon carbide, which has good thermal conductivity, as the main component of the base 10. Furthermore, electrical insulation between the base 10 and the wiring conductor 20 can be ensured by interposing the intermediate body 30, which is mainly composed of inorganic crystal particles, between the base 10 and the wiring conductor 20. Furthermore, by including inorganic crystal particles, which have better thermal conductivity than glass, as the main component of the intermediate body 30, heat generated in the wiring conductor 20 can be transferred to the base 10 via the intermediate body 30 more quickly than when glass is used as the main component of the intermediate body 30.

[0027] Second Embodiment Next, a ceramic structure according to a second embodiment will be described. Fig. 2 is a cross-sectional view schematically showing the ceramic structure according to the second embodiment. The ceramic structure 1A shown in Fig. 2 includes a base 10, a wiring conductor 20, and an intermediate body 30. In the ceramic structure 1A according to the second embodiment, the flow path 103 may be located inside the base 10 so as to surround the periphery of the wiring conductor 20 and the intermediate body 30.

[0028] The base 10 contains silicon carbide as a main component. For example, the base 10 may have a disk shape, a rectangular shape, or a rod shape with thicknesses at the top and bottom. The wiring conductor 20 may be located inside the base 10, sandwiching a region A that electrically isolates the base 10. For example, as in the illustrated example, the wiring conductor 20 may be embedded in the center of the base 10. The wiring conductor 20 may be made of, for example, high-melting-point tungsten or molybdenum. For example, as in the illustrated example, the entire region A that electrically isolates the base 10 and the wiring conductor 20 may be filled with the intermediate body 30. In other words, the periphery of the wiring conductor 20 may be covered by the intermediate body 30. The periphery of the intermediate body 30 may then be covered by the base 10. The base 10 and the wiring conductor 20 may be in contact with each other via the intermediate body 30. The intermediate body 30 may be cylindrical and surround the wiring conductor 20. The intermediate body 30 may be, for example, yttrium oxide, zirconium oxide, or aluminum nitride, which has a high melting point and insulating properties.

[0029] The flow path 103 may be positioned so as to surround the wiring conductor 20 and the intermediate body 30 from the outer periphery of the wiring conductor 20 and the intermediate body 30. This facilitates heat transfer from the wiring conductor 20 toward the flow path 103, further promoting heat exchange. For example, if the wiring conductor 20 and the intermediate body 30 are rod-shaped, the rod-shaped intermediate body 30 and the wiring conductor 20 may be inserted inside the flow path 103 of the base 10 in which the cylindrical flow path 103 is formed. The flow path 103 may be formed in a rectangular tube or a cylindrical shape. However, the flow path 103 is not limited thereto, and may be positioned so as to cover a portion of the wiring conductor 20 and the intermediate body 30. For example, the flow path 103 may be positioned so as to cover at least one of the upper, lower, or side portions of the wiring conductor 20 and the intermediate body 30 via the base 10. The flow path 103 is an example of a first flow path positioned inside the base 10.

[0030] Effect of Second Embodiment In the ceramic structure 1A according to the second embodiment, heat exchange can be promoted by including silicon carbide, which has good thermal conductivity, in the main component of the base 10. Furthermore, by interposing the intermediate body 30, which is mainly composed of inorganic crystal particles, between the base 10 and the wiring conductor 20, electrical insulation between the base 10 and the wiring conductor 20 is ensured, while improving thermal conduction compared to when the main component of the intermediate body 30 contains glass. Furthermore, by surrounding the periphery of the intermediate body 30 with the flow path 103, heat generated in the wiring conductor 20 can be quickly transferred to the base 10 via the intermediate body 30.

[0031] Third Embodiment Next, a ceramic structure according to a third embodiment will be described. Fig. 3 is a cross-sectional view schematically showing the ceramic structure according to the third embodiment. The ceramic structure 1B shown in Fig. 3 includes a base 10, a wiring conductor 20, and an intermediate body 30. In the ceramic structure 1B according to the third embodiment, a flow path 401 may be formed in a flow path member 40 that contacts the base 10.

[0032] The base 10 contains silicon carbide as a main component. For example, the base 10 and the flow path member 40 may have a disk or rectangular shape with thicknesses at the top and bottom. The wiring conductor 20 may be located inside the base 10, sandwiching a region A that electrically isolates the base 10. The wiring conductor 20 may be made of, for example, high-melting-point tungsten or molybdenum. For example, as in the illustrated example, the entire region A that electrically isolates the base 10 and the wiring conductor 20 may be filled with the intermediate body 30. In other words, the periphery of the wiring conductor 20 may be covered by the intermediate body 30. The periphery of the intermediate body 30 may then be covered by the base 10. The base 10 and the wiring conductor 20 may be in contact with each other via the intermediate body 30. The intermediate body 30 may be cylindrical and surround the wiring conductor 20. The intermediate body 30 may be, for example, yttrium oxide, zirconium oxide, or aluminum nitride, which has a high melting point and is insulating.

[0033] The substrate 10 does not need to have a flow path therein. This simplifies the internal structure of the substrate 10, making it easier to manufacture the ceramic structure 1B. The ceramic structure 1B further has a flow path member 40. The flow path member 40 may be in contact with any surface of the substrate 10. For example, in the illustrated example, the flow path member 40 is in contact with the lower surface of the substrate 10. A flow path 401 may be located inside the flow path member 40. The flow path 401 is an example of a second flow path located inside the flow path member 40.

[0034] The flow path member 40 may contain a metal such as aluminum as a main component. The flow path member 40 may contain silicon carbide as a main component. The thermal conductivity of silicon carbide at 20°C is approximately 200 [W / (m·K)]. In contrast, the thermal conductivity of aluminum (Al) at 20°C is approximately 200 [W / (m·K)], and the thermal conductivity of copper (Cu) at 20°C is approximately 370 [W / (m·K)]. Therefore, by including a metal such as aluminum with high thermal conductivity as a main component of the flow path member 40, heat from the wiring conductor 20 can be quickly exchanged by the flow path member 40.

[0035] (Effects of the Third Embodiment) In the ceramic structure 1B according to the third embodiment, heat exchange can be promoted by including silicon carbide, which has good thermal conductivity, as the main component of the base 10. Furthermore, the intermediate body 30 ensures electrical insulation between the base 10 and the wiring conductor 20, while the flow path member 40 in contact with the base 10 promotes heat exchange. Furthermore, since the base 10 does not have a flow path inside, the internal structure of the base 10 can be simplified, making it easier to manufacture the ceramic structure 1B.

[0036] Fourth Embodiment Next, a ceramic structure according to a fourth embodiment will be described. Fig. 4 is a cross-sectional view schematically showing the ceramic structure according to the fourth embodiment. The ceramic structure 1C shown in Fig. 4 includes a substrate 10, a wiring conductor 20, and an intermediate body 30. In the ceramic structure 1C according to the fourth embodiment, the intermediate body 30 may be plate-shaped.

[0037] The base 10 contains silicon carbide as a primary component. For example, the base 10 and the intermediate body 30 may have a disk or rectangular shape with thicknesses on both sides. The wiring conductor 20 may be located inside the base 10, sandwiching a region A electrically isolating the base 10. The wiring conductor 20 may be made of, for example, high-melting-point tungsten or molybdenum. For example, as in the illustrated example, the entire region A electrically isolating the base 10 and the wiring conductor 20 may be filled with the intermediate body 30. In other words, the periphery of the wiring conductor 20 may be covered by the intermediate body 30. The upper and lower surfaces of the intermediate body 30 may be covered by the base 10. The base 10 and the wiring conductor 20 may be in contact with each other via the intermediate body 30. The intermediate body 30 may be in the form of a plate surrounding the wiring conductor 20. The intermediate body 30 may be, for example, yttrium oxide, zirconium oxide, or aluminum nitride, which has a high melting point and insulating properties.

[0038] The base 10 has a base 10A and a base 10B. The intermediate 30 may be sandwiched between the base 10A and the base 10B. For example, the upper surface of the intermediate 30 may be in contact with the lower surface of the base 10A. The lower surface of the intermediate 30 may be in contact with the upper surface of the base 10B. The base 10A and the base 10B may be in contact with each other via the intermediate 30. The side surface of the intermediate 30 may be exposed.

[0039] The flow path 104 may be located inside the base 10A. The flow path 105 may be located inside the base 10B. The flow paths 104 and 105 may be located above and below the wiring conductor 20. The flow paths 104 and 105 are an example of a first flow path located inside the base 10A.

[0040] Effect of Fourth Embodiment In the ceramic structure 1C according to the fourth embodiment, heat exchange can be promoted by including silicon carbide, which has good thermal conductivity, as the main component of the base 10. Furthermore, the intermediate body 30 ensures electrical insulation between the base 10 and the wiring conductor 20, while the flow paths 104, 105 within the base 10 promote heat exchange.

[0041] Fifth Embodiment Next, a ceramic structure according to a fifth embodiment will be described. Fig. 5 is a cross-sectional view schematically showing the ceramic structure according to the fifth embodiment. A ceramic structure 1D shown in Fig. 5 includes a base 10, a wiring conductor 20, and an intermediate body 30. In the ceramic structure 1D according to the fifth embodiment, a portion of a region A electrically isolating the base 10 and the wiring conductor 20 may be a cavity 31.

[0042] The base 10 contains silicon carbide as a main component. For example, the base 10 and the intermediate body 30 may have a disk or rectangular shape with thicknesses on the top and bottom. The wiring conductor 20 may be made of, for example, high-melting-point tungsten or molybdenum.

[0043] The base 10 has a base 10C and a base 10D. The intermediate 30 may be sandwiched between the base 10C and the base 10D. For example, the upper surface of the intermediate 30 may be in contact with the lower surface of the base 10C. The lower surface of the intermediate 30 may be in contact with the upper surface of the base 10D. The base 10C and the base 10D may be in contact via the intermediate 30. The side surface of the intermediate 30 may be exposed. The lower surface of the base 10C may have a recess 11. The recess 11 may have any shape, such as a ring shape or a rod shape.

[0044] The entire surface of the wiring conductor 20 does not have to be in contact with the intermediate body 30. At least a portion of the wiring conductor 20 may be in contact with the intermediate body 30. In the illustrated example, the wiring conductor 20 is located on the base 10 across a region A that is electrically isolated from the base 10. In the region A, the lower surface of the wiring conductor 20 may be in contact with the intermediate body 30. A portion of the region A where the intermediate body 30 is not present may have a cavity 31. That is, the wiring conductor 20 may face the upper surface and side surface of the recess 11 in the region A where the intermediate body 30 is not located, via the cavity 31. The intermediate body 30 may be, for example, yttrium oxide, zirconium oxide, or aluminum nitride, which has a high melting point and insulating properties.

[0045] In the illustrated example, the recess 11 is located on the lower surface of the base 10C, but it may also be located on the upper surface of the base 10D. The recess 11 may be located on both the lower surface of the base 10C and the upper surface of the base 10D. The wiring conductor 20 may be located in the recess located on the upper surface of the base 10D, with the region A sandwiched between them. The flow path 106 may also be located inside the base 10D. The flow path 106 may also be located inside the base 10C. The flow path 106 may also be located in both the base 10C and the base 10D. The flow path 106 is an example of a first flow path located inside the base 10A.

[0046] Effect of Fifth Embodiment In the ceramic structure 1D according to the fifth embodiment, heat exchange can be promoted by including silicon carbide, which has good thermal conductivity, in the main component of the base 10. Furthermore, the intermediate body 30 and the cavity 31 ensure electrical insulation between the base 10 and the wiring conductor 20, while the flow path 106 in the base 10 promotes heat exchange.

[0047] Because the interior of the cavity 31 is filled with air, the cavity 31 has a lower thermal conductivity than the base 10. For this reason, the heat generated from the wiring conductor 20 is unlikely to be conducted to the base 10C side through the cavity 31. Therefore, the heat generated from the wiring conductor 20 can be guided to the intermediate body 30 side and transferred to the base 101D. This allows the heat from the wiring conductor 20 to be transferred to the flow path 106 side, facilitating heat exchange.

[0048] Sixth Embodiment Next, a ceramic structure according to a sixth embodiment will be described. Fig. 6A is a plan view schematically showing the ceramic structure according to the sixth embodiment. Fig. 6B is a cross-sectional view schematically showing the ceramic structure according to the sixth embodiment. Fig. 6B is a cross-sectional view (hereinafter referred to as "side cross-sectional view") of the ceramic structure 1E taken along the arrows II in Fig. 6A.

[0049] 6A and 6B, the base 10 includes a base 10E and a base 10F. The bases 10E and 10F may be stacked one above the other with an intermediate body 30 sandwiched therebetween. As shown in Fig. 6A, when the ceramic structure 1E is viewed from above, an electronic component 50 may be placed on the upper surface of the base 10E.

[0050] As shown in Fig. 6B, the wiring conductor 20 may be located between the base body 10E and the base body 10F via an intermediate body 30. The wiring conductor 20 and the intermediate body 30 may extend laterally between the base body 10E and the base body 10F. The wiring conductor 20 and the intermediate body 30 extending laterally may also extend perpendicularly to the thickness direction of the base body 10E along the left outer side surface of the base body 10E. The wiring conductor 20 may be exposed near the upper surface of the base body 10E. The exposed wiring conductor 20 and the electronic component 50 may be connected by brazing or the like.

[0051] (Effects of the Sixth Embodiment) The wiring conductor 20 may be connected to an electrode (not shown). By supplying power to the electrode, a current flows through the electronic component 50 via the wiring conductor 20. This allows the electronic component 50 to operate. The base 10E and the base 10F contain silicon carbide as a main component. This allows heat generated from the wiring conductor 20 and the electronic component 50 to be quickly dissipated to the outside of the base 10. In addition, the wiring conductor 20 is embedded between the base 10E and the base 10F via the intermediate body 30. This allows the base 10E and the base 10F to be electrically insulated from the wiring conductor 20.

[0052] Seventh Embodiment Next, a ceramic structure according to a seventh embodiment will be described. Fig. 7A is a plan view schematically showing the ceramic structure according to the seventh embodiment. Fig. 7B is a cross-sectional view schematically showing the ceramic structure according to the seventh embodiment. Fig. 7B is a side cross-sectional view of the ceramic structure 1F taken along the arrows II-II in Fig. 7A.

[0053] 7A and 7B, the base 10 includes a base 10G and a base 10H. The bases 10G and 10H may be stacked one above the other with an intermediate body 30 sandwiched therebetween. As shown in FIG. 7A, when the ceramic structure 1F is viewed from above, an electronic component 50 may be placed on the upper surface of the base 10G. An opening 10G1 may be formed in the upper surface of the base 10G.

[0054] As shown in FIG. 7B , the wiring conductor 20 may be located between the base body 10G and the base body 10H via the intermediate body 30. The wiring conductor 20 and the intermediate body 30 may extend laterally between the base body 10G and the base body 10H. A portion of the wiring conductor 20 extending laterally may be exposed from the opening 10G1 without the intermediate body 30. The wiring conductor 20 exposed from the opening 10G1 may be connected to a power supply terminal 21. The power supply terminal 21 is a conductor and may extend in the thickness direction of the base body 10G and protrude from the upper surface of the base body 10E. The wiring conductor 20 and the electronic component 50 may be electrically connected by wire bonding using the power supply terminal 21 and the wiring 22, a ball grid array (BGA), brazing, or the like. Although not shown, the electronic component 50 may be connected to another power supply terminal.

[0055] Effect of Seventh Embodiment The wiring conductor 20 and the power supply terminal 21 may be connected to electrodes (not shown). By supplying power to the electrodes, a current flows through the electronic component 50 via the wiring conductor 20 and the power supply terminal 21. This allows the electronic component 50 to operate. The base 10G and the base 10H contain silicon carbide as a main component. This allows heat generated from the wiring conductor 20 and the electronic component 50 to be quickly dissipated to the outside of the base 10. Furthermore, the base 10G has an opening 10G1, which also allows this heat to be quickly dissipated. Furthermore, the wiring conductor 20 is routed between the base 10G and the base 10H via the intermediate body 30 or the space within the opening 10G1. This allows the base 10G and the base 10H to be electrically insulated from the wiring conductor 20.

[0056] Eighth Embodiment Next, a ceramic structure according to an eighth embodiment will be described below. Fig. 8 is a cross-sectional view schematically showing the ceramic structure according to the eighth embodiment.

[0057] 8 , in a ceramic structure 1G according to the eighth embodiment, a wiring conductor 20 may be located on the upper surface of a base 10 via an intermediate body 30. The wiring conductor 20 may be covered with the intermediate body 30. A power supply terminal 21 and an electronic component 50 may be located on the upper surface of the intermediate body 30. However, this is not limiting, and the electronic component 50 may be located on the upper surface of the base 10.

[0058] The wiring conductor 20 and the intermediate body 30 may extend laterally on the upper surface of the base body 10. The wiring conductor 20 extending laterally may be connected to a power supply terminal 21 on the upper surface of the intermediate body 30. The wiring conductor 20 and the electronic component 50 may be electrically connected by wire bonding using the power supply terminal 21 and the wiring 22, a ball grid array (BGA), brazing, or the like.

[0059] The base 10 may have a flow path 107. The flow path 107 is an example of a first flow path located inside the base 10. Furthermore, the base 10 has an inlet 107a that communicates with the flow path 107 and through which the fluid flows in, and an outlet 107b through which the fluid flows out. For example, the piping connected to the inlet 107a and the piping connected to the outlet 107b may be connected to a chiller unit or the like that supplies a heat exchange medium. The heat exchange medium flows in from the inlet 107a, flows through the flow path 107 inside the base 10, and flows out from the outlet 107b, thereby circulating.

[0060] Effect of Eighth Embodiment The base 10 has the flow paths 107, which allows heat from the wiring conductors 20 and the electronic components 50 to be transferred to the flow paths 107 side, thereby facilitating heat exchange.

[0061] Furthermore, the ceramic structure 1G may function as a heat exchanger 100A. The heat exchanger 100A may further include a plurality of fins 60 in contact with the ceramic structure 1G. The plurality of fins 60 are an example of a heat dissipation member in contact with the ceramic structure. This allows heat to be dissipated from the base 10, further facilitating heat exchange. For example, if the electronic component 50 is an LED (light-emitting diode), the electronic component 50 may generate heat. In this case as well, the cooling effect of the electronic component 50 can be enhanced.

[0062] The heat exchanger 100A may have a flow path member in contact with the ceramic structure 1G in addition to the flow path 107 in the base 10. However, the heat exchanger is not limited to this, and may have no flow path in the base 10 but include a ceramic structure 1B and a flow path member 40 in contact with the base 10, as in the heat exchanger 100 shown in Fig. 3. The flow path 107 located inside the base 10 is an example of a first flow path. The flow path located inside the flow path member 40 is an example of a second flow path.

[0063] Ninth Embodiment Next, a ceramic structure according to a ninth embodiment will be described. FIGS. 9A and 9B are cross-sectional views schematically illustrating a ceramic structure according to the ninth embodiment. As illustrated in FIGS. 9A and 9B, the electronic component 51 may be any type of sensor, such as a temperature sensor, a speed sensor, an acceleration sensor, a vibration sensor, a pressure sensor, or a humidity sensor. The ceramic structures 1H illustrated in FIGS. 9A and 9B have the same configuration, and differ only in the position of the electronic component 51. However, the position of the electronic component 51 is not limited to the position illustrated in FIGS. 9A and 9B.

[0064] 9A and 9B, the base 10 includes a base 10I and a base 10J. The base 10I and the base 10J may be stacked one above the other with an intermediate body 30 sandwiched therebetween. An opening 10I1 may be formed in the upper surface of the base 10I. In the example shown in FIG. 9A, the electronic component 51 is located on the upper surface of the base 10I. In the example shown in FIG. 9B, the electronic component 51 is located inside the opening 10I1 of the base 10I.

[0065] The wiring conductor 20 may be located between the base 10I and the base 10J via the intermediate body 30. The wiring conductor 20 and the intermediate body 30 may extend laterally between the base 10I and the base 10J. A portion of the wiring conductor 20 extending laterally may be exposed from the opening 10I1 without being connected via the intermediate body 30. The wiring conductor 20 exposed from the opening 10I1 may be electrically connected to the electronic component 51 using a wiring 22 by brazing or the like.

[0066] Effect of the Ninth Embodiment The wiring conductor 20 may be connected to an electrode (not shown). By supplying power to the electrode, a current flows through the electronic component 51 via the wiring conductor 20. This allows the electronic component 51 to operate. The base 10I and the base 10J contain silicon carbide as a main component. This allows heat generated from the wiring conductor 20 and the electronic component 51 to be quickly dissipated to the outside of the base 10. Furthermore, the base 10I has an opening 10I1, which also allows this heat to be quickly dissipated. Furthermore, the wiring conductor 20 is routed between the base 10I and the base 10J via the intermediate body 30 or the space within the opening 10I1. This allows the base 10I and the base 10J to be electrically insulated from the wiring conductor 20.

[0067] For example, the electronic component 51 may be a temperature sensor that predicts the temperature based on the change over time in the resistance value of the wiring conductor 20 that serves as a heating resistor. In this case, the wiring conductor 20 may be used as two types of thermocouples. In this case, when the two types of wiring conductors 20 are brought into contact, the resistance value changes with temperature changes. The electronic component 51 may measure the temperature by measuring the electrical resistance of the wiring conductor 20, taking advantage of this property that the resistance value changes with temperature changes.

[0068] Furthermore, for example, the wiring conductor 20 may be used not only as a resistance heating element (heater) or an electrical supply (wiring), but also as an RTD (Resistance Temperature Detector). In this case, the ceramic structure 1 can also be used as a temperature measuring member for measuring the temperature of an object in contact with the ceramic structure 1.

[0069] It is desirable that an oxide film be present on the outer surface of the ceramic structure 1. When ceramics are subjected to a surface treatment, microcracks may occur. The presence of microcracks may result in a decrease in mechanical properties. Covering the microcracks with an oxide film suppresses the growth of the microcracks even when external stress is applied, thereby increasing the reliability of the mechanical strength.

[0070] (Method for manufacturing ceramic structure) A method for manufacturing the ceramic structure 1 will be briefly described. A sheet containing silicon carbide powder as a main component and an organic binder is prepared. The sheet may have spaces formed therein to serve as flow paths, or may not have spaces formed therein. In addition, a sheet serving as an intermediate body containing yttria oxide powder or the like as a main component and an organic binder is prepared. If the intermediate body 30 is to be a porous body, a raw material with a large particle size may be used, or a sheet containing a pore-forming material that decomposes when heated may be prepared. In addition, a sheet or paste serving as a wiring conductor made of a conductor such as tungsten is prepared.

[0071] In this case, the sheet that will become the wiring conductor 20 may be formed thinner than the sheet that will become the intermediate body 30. Alternatively, multiple sheets may be stacked in advance so that the sheet that will become the wiring conductor 20 is covered with the sheet that will become the intermediate body 30, and then sheets containing silicon carbide as a main component may be stacked on top and bottom of the stack. By stacking in this manner, a molded body can be produced. If the wiring conductor 20 is formed from a paste, it can be formed by printing the paste on the intermediate body 30. If the wiring conductor 20 has a vertically conductive structure as shown in FIGS. 6A, 6B, and 8, corresponding holes can be formed in the sheet that will become the intermediate body 30 and the paste can be injected into the holes. The laminated molded body may be simultaneously sintered at a temperature (approximately 1400°C to 2000°C) that does not or only slightly deteriorates its strength. The difference in thermal contraction between the base body 10, the intermediate body 30, and the wiring conductor 20 may be adjusted using a binder. This allows the ceramic structure 1 to be produced. When the intermediate body 30 is a porous body, the porosity of the porous body may be 5% by volume or more and 40% by volume or less.

[0072] To form an oxide film, heat treatment may be performed at a temperature of 900°C to 1200°C, similar to the atmospheric temperature. However, when the wiring conductor 20 is made of tungsten or molybdenum, it tends to be easily oxidized in a high-temperature atmospheric temperature. To prevent oxidation of the wiring conductor 20, the wiring conductor 20 and the intermediate body 30 may be laminated so as to be surrounded by silicon carbide to form a molded body, which may then be fired. The fired body may then be subjected to heat treatment to form an oxide film. The silicon carbide may then be removed to expose the wiring conductor.

[0073] Further advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

[0074] For example, in the ceramic structure, the number of wiring conductors 20 and intermediate bodies 30 may be one or two or more. A plurality of wiring conductors 20 and intermediate bodies 30 may be provided, or they may be branched or internally connected. Furthermore, in the ceramic structure, the number of flow paths inside the base 10 may be one, two or more, or none. Furthermore, in the ceramic structure, the number of flow path members 40 in contact with the base 10 may be one, two or more, or none.

[0075] The ceramic structure can function as an electrostatic chuck that electrostatically attracts a substrate, such as a semiconductor wafer, placed on the upper surface of the base 10 by applying a DC voltage to the attraction electrode that is conductive to the wiring conductor 20, and is mounted on a substrate processing apparatus that processes the substrate. Furthermore, by forming a flow path for vacuum attraction within the base 10, the ceramic structure can function as a vacuum chuck that vacuum attracts a substrate placed on the upper surface of the base 10, and is mounted on a substrate processing apparatus that processes the substrate.

[0076] The present technology can be configured as follows. (1) A ceramic structure comprising: a base containing silicon carbide as a main component; a wiring conductor located on the base across a region electrically isolated from the base; and an intermediate located in at least a portion of the region, having a volume resistivity higher than that of the base and that of the wiring conductor, the intermediate containing inorganic crystalline particles as a main component. (2) The ceramic structure according to (1), in which the inorganic crystalline particles are mainly composed of yttrium oxide or zirconium oxide. (3) The ceramic structure according to (2), in which the intermediate contains silicon carbide. (4) The ceramic structure according to (3), in which a mass of the silicon carbide relative to a total mass of the intermediate is 1 mass% or less. (5) The ceramic structure according to any one of (1) to (4), in which at least a portion of the wiring conductor is located inside the base. (6) The ceramic structure according to any one of (1) to (5), in which at least a portion of the intermediate is located inside the base. (7) The ceramic structure according to any one of (1) to (6), wherein the base has a first flow path located inside the base, and an inlet through which a fluid flows in and an outlet through which the fluid flows out, which are connected to the first flow path. (8) The ceramic structure according to any one of (1) to (7), wherein a region of the region in which the intermediate body is not located is a cavity. (9) The ceramic structure according to any one of (1) to (8), wherein the wiring conductor is a heating resistor. (10) A heat exchanger comprising: the ceramic structure according to any one of (1) to (9); and a flow path member in contact with the ceramic structure, wherein the flow path member has a second flow path located inside the flow path member. (11) The heat exchanger according to (10), comprising a heat dissipation member in contact with the ceramic structure.

[0077] DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H: Ceramic structure 10, 10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 10I, 10J: Base 20: Wiring conductor 21: Power supply terminal 22: Wiring 30: Intermediate body 31: Cavity 40: Flow path member 50, 51: Electronic component 60: Fin 100, 100A: Heat exchanger 101 to 107, 401: Flow path 107a: Inlet 107b: Outlet

Claims

1. A ceramic structure comprising: a substrate containing silicon carbide as a primary component; a wiring conductor located on the substrate across a region electrically isolated from the substrate; and an intermediate located in at least a portion of the region, having a volume resistivity higher than that of the substrate and that of the wiring conductor, the intermediate containing inorganic crystal particles as a primary component.

2. The ceramic structure according to claim 1, wherein the inorganic crystal particles are primarily composed of yttrium oxide or zirconium oxide.

3. The ceramic structure of claim 2, wherein the intermediate body comprises silicon carbide.

4. The ceramic structure according to claim 3, wherein the mass of the silicon carbide relative to the total mass of the intermediate body is 1 mass % or less.

5. The ceramic structure according to any one of claims 1 to 4, wherein at least a portion of the wiring conductor is located inside the substrate.

6. The ceramic structure according to any one of claims 1 to 5, wherein at least a portion of the intermediate body is located inside the substrate.

7. The ceramic structure according to any one of claims 1 to 6, wherein the substrate has a first flow path located inside the substrate, and an inlet through which a fluid flows in and an outlet through which the fluid flows out, both of which communicate with the first flow path.

8. The ceramic structure according to any one of claims 1 to 7, wherein the region where the intermediate is not located is a cavity.

9. The ceramic structure according to any one of claims 1 to 8, wherein the wiring conductor is a heating resistor.

10. A heat exchanger comprising: a ceramic structure according to any one of claims 1 to 9; and a flow path member in contact with said ceramic structure, said flow path member having a second flow path located inside said flow path member.

11. The heat exchanger according to claim 10, further comprising a heat dissipation member in contact with said ceramic structure.

Images