Ceramic member and substrate holding member

Abstract

To provide a ceramic member and a substrate holding member in which peeling and warpage of an electrode embedding member from the ceramic member are suppressed, a stable structure can be obtained, and multiple functions can be provided according to various purposes.SOLUTION: The ceramic member 100 includes a base material 110 composed of a ceramic sintered compact and a metallic film 120 formed on at least a part of the base material 110, wherein the metallic film 120 contains Al of ≥ 97wt% or Al of ≥ 70wt% and ≤ 98. 7wt% as a main component.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a ceramic member and a substrate holding member. [Background technology]

[0002] In semiconductor processes, particularly plasma processes using high frequency power, substrate holders have traditionally been used, in which ceramic electrode-embedded members are arranged on an Al substrate.

[0003] Patent Document 1 discloses a substrate support used in a plasma processing apparatus, the substrate support comprising: a base; an electrostatic chuck provided on the base, the electrostatic chuck including a dielectric portion formed from a dielectric material, the dielectric portion being joined to the base by brazing or diffusion bonding; and a coating layer covering at least a portion of the surface of the base, the coating layer including an insulating layer formed from an insulating material, the base being formed from an alloy having a linear expansion coefficient of 7 ppm / °C or more and 8 ppm / °C or less.

[0004] Patent Document 2 discloses a substrate support used in a plasma processing apparatus, the substrate support comprising a base made of ceramic, an electrostatic chuck provided on the base, and a plurality of electrodes, wherein the electrostatic chuck has a central region configured to support a substrate placed thereon, an annular region extending to surround the central region and configured to support an edge ring placed thereon, and a coating layer that forms the surface of the electrostatic chuck, and the plurality of electrodes include a first metal layer provided between the central region and the base, and a second metal layer provided between the annular region and the base. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2024-11192 [Patent Document 2] Japanese Patent Application Publication No. 2024-18988 Summary of the Invention [Problem to be solved by the invention]

[0006] Recently, plasma processes have become more heat-intensive, and large amounts of power are being applied to the substrate. As a result, differences in CTE between the Al substrate and the electrode-embedded material can cause delamination between the two, or excessive warping of the Al substrate or electrode-embedded material, causing problems with the process. In addition, high-frequency current can concentrate at the power supply terminals attached to the ceramic substrate, causing localized non-uniformity in the temperature near the power supply terminals.

[0007] In the technology described in Patent Document 1, an alloy with a relatively low linear expansion coefficient is used as the material of the base, but the difference in CTE with the ceramic electrode-embedded member may still be large in some cases, and the risk of peeling or warping cannot be sufficiently reduced. Also, in the technology described in Patent Document 2, although both the base and the electrostatic chuck are made of ceramic, the metal layer is only used as an electrode or terminal.

[0008] Therefore, there has been a demand for a substrate holder that combines a substrate made of a sintered ceramic body, which has a structure that is stable against the large heat input of the process, with an electrode-embedding member also made of a sintered ceramic body.In addition, there has been a demand for a substrate made of a sintered ceramic body that can be made multifunctional to suit various purposes.

[0009] The present invention has been made in consideration of the above circumstances, and aims to provide a ceramic member and a substrate holding member that can be made multifunctional for various purposes, while suppressing peeling and warping of the electrode-embedded member from the ceramic member and achieving a stable structure. [Means for solving the problem]

[0010] (1) In order to achieve the above object, the present invention provides the following means: That is, a ceramic member according to an application example of the present invention is a ceramic member comprising a substrate made of a ceramic sintered body and a metal film formed on at least a part of the surface of the substrate, wherein the metal film is mainly composed of Al with a purity of 97 wt% or more or an Al alloy containing 70 wt% to 98.7 wt% of Al.

[0011] This allows the metal film to be thicker than conventional products, which in turn increases the electrical conductivity of the substrate surface and makes it possible to process the metal film itself, making ceramic components multifunctional depending on their application.

[0012] (2) In the ceramic member according to the application example of (1) above, the metal film is a metal-based composite film containing at least one of SiC, Al2O3, diamond, and c-BN as a filler. This allows the CTE of the metal film to be close to the CTE of the substrate. As a result, a thicker film can be formed without peeling.

[0013] (3) In addition, in the ceramic member according to the application example of (1) or (2) above, the ceramic member is characterized by further comprising a base metal film containing a noble metal formed between the substrate and the metal film, thereby making it possible to improve the properties of the entire film, which is the combination of the base metal film and the metal film, according to the purpose.

[0014] (4) In addition, in the ceramic member according to any one of the application examples (1) to (3), the ceramic sintered body contains SiC as a main component, and when the thickness of the metal film is T (μm), the thermal expansion coefficient of the metal film is α1 (ppm / K), the thermal expansion coefficient of the base material is α2 (ppm / K), the aspect ratio of Al or Al alloy forming the metal film is A, and the Young's modulus of the base material is E (GPa), the following mathematical formula (1) is satisfied: 0.25≦(T×α1 2 ×A 0.5 ) / {(α1-α2) 2× E}≦3.0 (1). This allows for the formation of thicker films without peeling.

[0015] (5) In addition, in the ceramic member according to any one of the application examples (1) to (4) above, the ceramic member is characterized by further comprising a second metal film formed on at least a portion of the surface of the metal film, the second metal film containing Al with a purity of 97 wt% or more or a second Al alloy containing 97 wt% or more of Al, thereby further increasing the electrical conductivity of the surface of the thickened metal film.

[0016] (6) Furthermore, a substrate holding member according to an application example of the present invention is characterized by comprising: a ceramic member according to any one of (1) to (5) above; and an electrode-embedded member having a substrate mounting surface joined to one main surface of the ceramic member.

[0017] This allows the substrate holding member to be made of a multi-functional ceramic member depending on the application, thereby expanding the functionality of the substrate holding member. [Effects of the Invention]

[0018] According to the ceramic member or substrate holding member of the present invention, peeling or warping of the electrode-embedded member from the ceramic member can be suppressed, resulting in a stable structure and enabling multi-functioning according to various purposes. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic cross-sectional view showing an example of a ceramic member according to a first embodiment of the present invention. [Figure 2] 1 is a schematic partially enlarged cross-sectional view showing an example of a ceramic member according to a first embodiment of the present invention. [Figure 3] FIG. 2 is a schematic diagram showing an example of particles made of Al or an Al alloy that form a metal film. [Figure 4]FIG. 3 is a schematic cross-sectional view showing a modified example of the ceramic member according to the first embodiment of the present invention. [Figure 5] FIG. 3 is a schematic cross-sectional view showing a modified example of the ceramic member according to the first embodiment of the present invention. [Figure 6] FIG. 4 is a schematic cross-sectional view showing an example of a ceramic member according to a second embodiment of the present invention. [Figure 7] 1 is a schematic cross-sectional view showing an example of a substrate holding member according to an embodiment of the present invention. [Figure 8] 1 is a table showing the measured values ​​of the metal film and substrate of each sample and the values ​​of formula (1). DETAILED DESCRIPTION OF THE INVENTION

[0020] Next, an embodiment of the present invention will be described with reference to the drawings. To facilitate understanding of the description, the same reference numerals are used to designate the same components in the drawings, and duplicated descriptions will be omitted. Note that in the configuration diagrams, the size of each component is shown conceptually and does not necessarily represent the actual dimensional ratio.

[0021] [First embodiment] (Configuration of ceramic components) A ceramic member according to a first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view showing an example of a ceramic member according to the first embodiment of the present invention. A ceramic member 100 according to the first embodiment of the present invention includes a substrate 110 and a metal film 120.

[0022] The substrate 110 is made of a sintered ceramic body. This allows structures such as a media flow path 118 to be provided inside the substrate 110. The substrate 110 can be made of, for example, ceramics containing SiC, ceramics containing AlN, or ceramics containing Al2O3. The substrate 110 is formed in a generally flat plate shape with a diameter of 200 mm or more and a thickness of 10 to 50 mm. The substrate 110 may have various shapes, such as a generally circular plate, a polygonal plate, or an elliptical plate.

[0023] The surface roughness Ra of the surface of the substrate 110 on which the metal film 120 is formed is preferably 0.1 μm or more and 10 μm or less, so that an appropriate anchor effect can be exerted on the metal film 120.

[0024] The substrate 110 is preferably made of ceramics with a thermal conductivity of 70 W / mK or more. This gives the substrate 110 itself a high thermal conductivity, making it suitable for use as a cooling substrate 110. Examples of ceramics with a thermal conductivity of 70 W / mK or more include ceramics containing SiC and ceramics containing AlN.

[0025] The substrate 110 is preferably formed of a ceramic sintered body primarily composed of SiC or AlN. "SiC-based" refers to a ceramic sintered body containing 50 wt% or more of SiC, or a ceramic sintered body containing SiC and having a thermal conductivity of 70 W / mK or more. "AlN-based" refers to a ceramic sintered body containing 50 wt% or more of AlN, or a ceramic sintered body containing AlN and having a thermal conductivity of 70 W / mK or more. SiC, in particular, can be used with aqueous media, which were previously avoided due to the risk of corrosion in the media flow paths of conventional Al substrates. Aqueous media have a high heat transfer coefficient and are suitable for absorbing large amounts of heat. Furthermore, SiC has high strength and high thermal conductivity, making it suitable for use as the cooling substrate 110.

[0026] The substrate 110 preferably has a media flow path 118 therein, so that the media in the media flow path 118 can absorb heat from the substrate.

[0027] When the substrate 110 includes the medium flow channel 118, the medium flow channel 118 may be formed in a tubular shape. In this case, the width of the medium flow channel 118 is preferably 1 mm or more and 60 mm or less. The cross-sectional shape of the medium flow channel 118 is not limited to a rectangle, and may be any manufacturable shape, such as a circle, an ellipse, a semicircle, or a stepped shape. The medium flow channel 118 preferably uses a low-temperature chiller for circulation. Therefore, the medium flow channel 118 is preferably formed with an inlet for introducing the chiller and an outlet for discharging the chiller. In this case, the medium flow channel 118 is connected to a chiller unit provided outside a reduced-pressure vessel or the like in which the substrate 110 is installed.

[0028] The shape of the medium flow path 118, when viewed from above through the substrate 110, may include a substantially circular or spiral shape centered at the center of the substrate 110. A substantially circular shape includes a shape in which some of the arcs of the circular ring are not connected, and a normal circular ring. A substantially spiral shape includes a shape in which the circumferential arc shape is connected with its curvature changing in the radial direction with the center of the substrate 110 as the base.

[0029] The medium flow paths 118 may be arranged concentrically around the center of the substrate 110 when viewed from above. The concentrically arranged, approximately annular medium flow paths 118 may be double, triple, or more. The concentrically arranged, approximately annular medium flow paths 118 may be connected inside the substrate 110, or each may have an inlet and an outlet formed therein.

[0030] The width of the gap between adjacent media flow channels 118 (the width of the substrate 110 present in the gap between adjacent media flow channels 118) is preferably 2 mm or more. Furthermore, the width of the gap between adjacent media flow channels 118 is preferably 25% or more of the width of the media flow channel 118. This allows the strength of the substrate 110 to be maintained even when the media flow channel 118 is formed inside the substrate 110 made of ceramic.

[0031] The medium flow passage 118 may include a linear shape. Alternatively, some of the substantially circular, spiral, or linear medium flow passages 118 may be combined. The substantially circular, spiral, or linear medium flow passages 118 may be connected to each other.

[0032] The metal film 120 is formed on at least a portion of the surface of the substrate 110. The metal film 120 is primarily composed of Al with a purity of 97 wt% or higher or an Al alloy containing 70 wt% to 98.7 wt% Al. This allows the metal film 120 to be made thicker than conventional products. As a result, it becomes possible to increase the electrical conductivity of the surface of the ceramic member 100 and to process the metal film 120 itself, making the ceramic member 100 multifunctional depending on the application.

[0033] The metal film 120 being primarily composed of Al or an Al alloy means that the metal film 120 contains 50 wt% or more of Al or an Al alloy. In addition to Al or an Al alloy, the metal film 120 may also contain filler 124 (described later). Al with a purity of 97 wt% or more refers to Al containing less than 3 wt% of unintended impurities. An Al alloy containing 70 wt% to 98.7 wt% of Al refers to existing Al alloys such as A5052 and A6061, which contain 1.3% or more of essential metal components other than Al, or Al alloys such as Al + 10-15 wt% Si + 1-5 wt% Mg. The Al alloy may contain less than 3 wt% of unintended impurities as a whole, as long as the intended properties are not impaired. The metal film 120 may contain voids.

[0034] The thickness of the metal film 120 is preferably 100 μm or more and 2000 μm or less, and more preferably 500 μm or more and 1400 μm or less. This prevents the ceramic sintered body of the substrate 110 from being exposed when the metal film 120 is processed. Furthermore, because the metal film 120 is not too thick, the risk of the metal film 120 peeling off can be reduced. If the metal film 120 is too thick, there is an increased risk of the metal film 120 peeling off at the interface with the substrate 110 or by scraping off the surface layer of the substrate 110. The metal film 120 can be formed by cold spraying, thermal spraying, or the like.

[0035] The thickness of the metal film 120 can be determined by observation with an optical microscope or a scanning electron microscope (SEM). Specifically, five points are randomly selected from the polished cross section perpendicular to the surface of the substrate 110 on which the metal film 120 is formed, and the thickness of the metal film 120 is determined at a magnification of 100 to 1000 times in a direction perpendicular to the interface between the substrate 110 and the metal film 120. The average of these values ​​is then determined as the thickness of the metal film 120.

[0036] FIG. 2 is a schematic, partially enlarged cross-sectional view illustrating an example of a ceramic member according to a first embodiment of the present invention. As shown in FIG. 2, the metal film 120 is preferably a metal-based composite film containing filler 124 in particles 122 made of Al or an Al alloy. The filler 124 contained in the metal film 120 is more preferably at least one of SiC, Al2O3, diamond, and c-BN. This allows the coefficient of thermal expansion (CTE) of the metal film 120 to approach the CTE of the substrate 110. As a result, a thicker film can be formed without peeling. When the metal film 120 is a metal-based composite film containing filler 124, the CTE of the metal film 120 is a value measured over the entire metal film 120, including the filler 124.

[0037] Depending on the application, the metal film 120 can be formed on, for example, part or all of one main surface 112 (top surface), the side surface 114, or the other main surface 116 (bottom surface) opposite the one main surface of the substrate 110. For example, forming the metal film 120 on at least a part of the side surface 114 of the substrate 110 enables power supply from the side surface of the substrate 110, thereby increasing the degree of freedom in designing the device structure including the substrate holding member 200. When the metal film 120 on the side surface 114 serves only the purpose of power supply, the thickness of the metal film 120 on the side surface may be 10 μm or more and 100 μm or less. Furthermore, when the metal film 120 on the side surface 114 serves only the purpose of power supply, the width of the metal film 120 on the side surface 114 in a direction parallel to one main surface 112 of the substrate 110 is preferably 50 mm or more.

[0038] The metal film 120 may be a high-frequency electrode. In this case, the metal film 120 is formed on at least a part of one main surface 112 of the base material 110. This allows the metal film 120 to function as an electrode to which high-frequency power is applied. When the metal film 120 is used as a high-frequency electrode, the ceramic member 100 includes a terminal electrically connected to the metal film 120 on the one main surface 112, or the metal film 120 formed on the side surface 114 of the base material 110.

[0039] A gas flow path may be formed in the metal film 120. The gas flow path can be formed, for example, for the purpose of distributing gas to be supplied to the electrode-embedded member 210 of the substrate holding member 200 described below. Forming a gas flow path in the metal film 120 can be done at a lower cost than forming a gas flow path in the base material 110 made of a ceramic sintered body.

[0040] When the ceramic sintered body forming the substrate 110 contains SiC as a main component, the thickness of the metal film 120 is T (μm), the thermal expansion coefficient of the metal film 120 is α1 (ppm / K), the thermal expansion coefficient of the substrate 110 is α2 (ppm / K), the aspect ratio of Al or Al alloy forming the metal film 120 is A, and the Young's modulus of the substrate 110 is E (GPa), the following mathematical formula (1) can be obtained: 0.25≦(T×α1 2 ×A 0.5 ) / {(α1-α2) 2 ×E}≦3.0 (1) It is preferable that the following condition is satisfied. This allows a thicker film to be formed without peeling. The thermal expansion coefficient is the average linear expansion coefficient between 25°C and 100°C.

[0041] When the metal film 120 is formed by cold spraying or thermal spraying, it is formed by depositing molten metal particles on a substrate. The adhesion of the metal particles to the substrate is affected by the thermal expansion coefficients of the substrate 110 and metal particles, the thickness of the metal film 120, the degree of deformation of the metal particles, and the preheat temperature of the substrate. The metal particles collide with the substrate at high speed due to the spray pressure, deforming and adhering to the substrate. As the spray pressure of the molten particles increases, the particle deformation increases. When the spray pressure is low, the metal particles maintain the shape of the raw material powder and the adhesion between adjacent particles is low, resulting in a sparse film with high porosity and low film strength. When the spray pressure is high, the particles deform, improving the adhesion between adjacent particles and resulting in a dense film with improved film strength. Furthermore, denser films also improve electrical properties and thermal conductivity. When sprayed at high pressure, the dimensions of the metal particles in the thickness direction are approximately 20 to 30 μm, and the dimensions of the metal particles in the horizontal direction are approximately 60 to 100 μm. If the spray pressure is too high, the surface of the substrate 110 may be damaged, weakening the bonding strength of the metal film 120. Therefore, it is preferable to adjust the spray pressure according to the material of the substrate 110. The spray pressure of the present invention is optimized in the range of 1.0 MPa to 10 MPa for ceramic sintered bodies containing SiC as the main component. The preheat temperature of the substrate 110 is adjusted in the range of 100°C to 300°C.

[0042] FIG. 3 is a schematic diagram showing an example of particles 122 made of Al or an Al alloy that form the metal film 120. The aspect ratio A of the Al or Al alloy that forms the metal film 120 can be determined by SEM observation. Specifically, a 100 μm × 100 μm field of view is observed at 1000x magnification on a polished cross section perpendicular to the surface of the substrate 110 on which the metal film 120 is formed. Next, of the particles 122 made of Al or an Al alloy that are in contact with the surface of the substrate 110, five particles with the largest particle diameters (longest diameters) are selected from the particles that are entirely contained within the SEM image. Next, H / L is calculated, where L is the maximum length of the selected particles in a direction parallel to the surface of the substrate 110 and H is the maximum length of the selected particles in a direction perpendicular to the surface of the substrate 110. The average value of H / L is then calculated to determine the aspect ratio A of the Al or Al alloy that forms the metal film 120. A total of 10 or more particles 122 made of Al or an Al alloy are observed from different fields of view.

[0043] Fig. 4 is a schematic cross-sectional view showing a modified example of the ceramic member according to the first embodiment of the present invention. As shown in Fig. 4, the ceramic member 100 preferably further includes a second metal film 130 formed on at least a portion of the surface of the metal film 120. The second metal film 130 contains Al with a purity of 97 wt% or more or a second Al alloy containing 97 wt% or more of Al. This can further improve the electrical conductivity of the surface of the thickened metal film 120. The metal film 120 and the second metal film 130 can be distinguished by the purity of Al, the composition of the Al alloy, or the presence or absence of a filler.

[0044] 5 is a schematic cross-sectional view showing a modified example of the ceramic member according to the first embodiment of the present invention. As shown in FIG. 5, an insulating layer 150 may be formed on the metal film 120 or the second metal film 130 on a part of the upper surface or side surface where the metal film 120 or the second metal film 130 is exposed. This allows electrical insulation from the process environment and the surroundings to be maintained. The insulating layer 150 is preferably formed, for example, by a thermally sprayed film of Al2O3.

[0045] [Second embodiment] (Configuration of ceramic components) A ceramic member according to a second embodiment of the present invention will be described with reference to FIG. 6. FIG. 6 is a schematic cross-sectional view showing an example of a ceramic member according to the second embodiment of the present invention. A ceramic member 100 according to the second embodiment of the present invention includes a substrate 110, a metal film 120, and a base metal film 140. Differences from the ceramic member 100 according to the first embodiment will be described below. Note that features of different embodiments may be combined and applied. The basic configurations of the substrate 110 and the metal film 120 of the ceramic member 100 according to the second embodiment are the same as the configurations of the ceramic member 100 according to the first embodiment.

[0046] The underlying metal film 140 is formed between the substrate 110 and the metal film 120 and contains a precious metal. This makes it possible to improve the properties of the entire film, which is the combination of the underlying metal film 140 and the metal film 120, depending on the purpose. The underlying metal film 140 may be formed only partially between the substrate 110 and the metal film 120.

[0047] The noble metals contained in the base metal film 140 include Cu, Ag, Au, Pt, other platinum group elements, W, Mo, and alloys thereof. The base metal film 140 may be a single noble metal or an alloy containing 50 wt% or more of these noble metals as a main component. For example, when the base metal film 140 contains Cu, it is preferable to use an Al alloy in the 2000, 5000, or 6000 series (e.g., A2014, A5052, A6061) for the metal film 120. This improves the strength of the entire film (including the base metal film 140, the metal film 120, and the second metal film 130) and allows the metal film 120 to be easily machined. Furthermore, when the base metal film 140 contains Ag, Au, Pt, or other platinum group elements, the electrical conductivity and thermal conductivity of the entire film can be improved.

[0048] The thickness of the base metal film 140 is preferably 20 μm or more and 100 μm or less. The base metal film 140 can be formed by cold spraying, thermal spraying, CVD, vapor deposition, plating, etc. When a metal film 120 is formed on the surface on which the base metal film 140 is formed, the particles used to determine the aspect ratio A of Al or Al alloy that forms the metal film 120 are selected from particles 122 made of Al or Al alloy that are in contact with the surface of the base metal film 140.

[0049] (Configuration of substrate holding member) Next, a substrate holding member according to an embodiment of the present invention will be described with reference to FIG. 7. FIG. 7 is a schematic cross-sectional view showing an example of a substrate holding member according to an embodiment of the present invention. A substrate holding member 200 according to an embodiment of the present invention includes a ceramic member 100 and an electrode-embedded member 210. The ceramic member is the same as described above. The ceramic member 100 of the substrate holding member 200 in FIG. 7 shows an example in which the ceramic member 100 according to the first embodiment is used, but the ceramic member 100 according to the second embodiment or a ceramic member 100 in which the ceramic member 100 according to the first embodiment and the ceramic member 100 according to the second embodiment are combined may also be used.

[0050] When the metal film 120 is formed on one main surface 112 of the base material 110, the electrode embedding member 210 is bonded to the upper surface of the metal film 120. When the metal film 120 is not formed on one main surface 112 of the base material 110, the electrode embedding member 210 is bonded to one main surface 112 of the base material 110. The electrode embedding member 210 may be bonded via a bonding layer 220, which will be described later. The electrode embedding member 210 has a substrate mounting surface 212.

[0051] An electrode 218 is embedded in the electrode-embedding member 210. The electrode 218 may have various shapes, such as a mesh shape or a foil shape, and may be made of various materials, such as molybdenum or tungsten. The electrode 218 embedded in the electrode-embedding member 210 may function as an electrostatic attraction electrode, a heater electrode, a high-frequency electrode, or the like. Two or more types of electrodes 218 may be embedded in the electrode-embedding member 210.

[0052] Power may be supplied to the electrode 218 via a metal film 120 formed on the side surface 114 of the substrate 110. This makes it possible to prevent hot spots caused by the power supply terminal. When the metal film 120 formed on one main surface 112 of the substrate 110 is used as a high-frequency electrode, the metal film 120 for supplying power to the high-frequency electrode and the metal film 120 for supplying power to the electrode 218 are formed so as to be separate systems. Power may be supplied to the electrode 218 via a power supply terminal (not shown).

[0053] The electrode-embedding member 210 is preferably made of an insulating ceramic sintered body. This allows the electrode-embedding member 210 to function as an insulating member that is electrically insulating, dense, and highly thermally conductive. The electrode 218 can also be easily embedded. The thickness of the electrode-embedding member 210 is preferably 1 mm or more and 20 mm or less.

[0054] The electrode-embedding member 210 is preferably made of ceramics containing AlN, Al2O3, or Y2O3 as its main component, and more preferably AlN, which has excellent thermal conductivity. "Mainly containing" refers to ceramics containing 50 wt% or more of this compound.

[0055] When the electrode-embedding member 210 is bonded using the bonding layer 220, the bonding layer 220 is formed on at least a portion of one main surface 112 of the substrate 110 or the upper surface of the metal film 120. The bonding layer 220 bonds the electrode-embedding member 210 to the substrate 110 or the metal film 120 formed on one main surface 112 of the substrate 110. The bonding layer 220 is preferably formed from a brazing material containing a metal such as In or Al, an inorganic adhesive, or an organic adhesive primarily composed of a resin material. Various resin-based adhesives can be used, such as silicone resin, fluororesin, acrylic resin, or epoxy resin. Among these, silicone resin or fluororesin, which has high heat resistance and flexibility, is preferably used. When the metal film 120 is formed on one main surface 112 of the substrate 110, the metal film 120 may serve as the bonding layer 220.

[0056] When the bonding layer 220 is formed from an organic adhesive, it is preferable that a filler be added to the adhesive to increase thermal conductivity. The thermal conductivity of the bonding layer 220 is preferably 0.4 W / mK or higher. Furthermore, it is preferable that the elongation of the bonding layer 220 is 100% or higher. The thickness of the bonding layer 220 is preferably 500 μm or less, and more preferably 100 μm or less. This allows a large amount of heat to be transferred. If the thickness is greater than 500 μm, the thermal resistance of the bonding layer 220 may not be negligible even if a highly thermally conductive metal or adhesive is used. The lower limit of the thickness of the bonding layer 220 can be, for example, 10 μm or more. This is because if the thickness is thinner than this, it becomes difficult to control the thickness.

[0057] [Method of manufacturing substrate holding member] Next, an example of a method for manufacturing a substrate holding member according to an embodiment of the present invention will be described. The method for manufacturing a substrate holding member according to an embodiment of the present invention includes the steps of preparing a substrate made of a ceramic sintered body, forming a metal film on at least a portion of the surface of the substrate, preparing an electrode-embedding member, and joining the substrate and the electrode-embedding member.

[0058] Below, as specific examples, we will explain a method for manufacturing a ceramic member, a method for manufacturing an electrode-embedded member, and a method for manufacturing a substrate holding member including a bonding method, in which the base material is formed of a SiC ceramic sintered body and the electrode-embedded member is formed of an AlN ceramic sintered body.

[0059] (Method of manufacturing the substrate) The substrate of the ceramic member according to the embodiment of the present invention is fabricated, for example, by a molded body hot pressing method described below. The method for fabricating the substrate is not limited to this method, and may be, for example, a powder hot pressing method or a conventional green sheet lamination method. The powder hot pressing method involves alternately stacking ceramic raw material powder and predetermined heating resistors and electrodes to embed the heating resistors and electrodes inside the ceramic, which is then uniaxially hot-pressed and fired. When forming a media flow path inside the substrate, it is preferable to fabricate it by a molded body hot pressing method.

[0060] The method for manufacturing a ceramic member substrate using a molded body hot pressing method according to an embodiment of the present invention includes a ceramic molded body forming step, a ceramic degreased body producing step, a firing step, a ceramic sintered body processing step, a substrate precursor bonding step, a substrate processing step, and a metal film forming step. Note that, although the following manufacturing method describes a ceramic member in which a media flow path is formed in the substrate, the media flow path may not be present.

[0061] In the ceramic green body forming process, for example, multiple ceramic green bodies are formed from ceramic raw material powder mainly composed of SiC (silicon carbide). Sintering aids and additives may be added as needed. For example, sintering aids such as B4C and C, and additives such as binders, plasticizers, and dispersants are appropriately added to and mixed with the SiC ceramic raw material powder to prepare a slurry, which is then granulated by a method such as spray drying. The additives may be nitrides, carbides, or borides of metals selected from Groups 4 to 6 of the periodic table. These components may be added to adjust the difference in linear expansion coefficient between the granulated powder and the electrode-embedded member. The granulated powder is then pressure-molded to form multiple ceramic green bodies.

[0062] The SiC ceramic raw material powder is preferably highly pure, preferably 96% or more, more preferably 99% or more, and even more preferably 99.9% or more. The average particle size of the SiC ceramic raw material powder is preferably 0.1 μm or more and 1.0 μm or less.

[0063] The mixing method may be either wet or dry, and a mixer such as a ball mill or a vibration mill may be used. The molding method may be a known method such as uniaxial pressing or cold isostatic pressing (CIP). The method for forming the ceramic compact is not limited to pressure molding; for example, green sheet lamination or slip casting may also be used. The ceramic compact can be manufactured by appropriately degreasing or further calcining the resulting product.

[0064] After molding, the ceramic molded body may be machined to adjust the shape of the molded body. The machining may be performed after degreasing.

[0065] In the ceramic degreased body production process, multiple ceramic molded bodies are degreased at a predetermined temperature or higher for a predetermined time or longer to produce multiple ceramic degreased bodies. The ceramic molded bodies are heat-treated, for example, at a temperature of 500°C to 900°C to produce ceramic degreased bodies. The degreasing time is preferably 1 hour to 120 hours. An atmospheric or nitrogen atmosphere furnace can be used for degreasing, but an atmospheric furnace is preferred to remove organic components from the binder.

[0066] In the firing process, the formed ceramic degreased body is subjected to uniaxial pressure firing or atmospheric pressure firing to form multiple ceramic sintered bodies. When uniaxial pressure firing is performed, the pressure is preferably 4 MPa or more. The firing temperature is preferably 2000°C or more and 2200°C or less. The firing time is preferably 1 hour or more and 12 hours or less, and more preferably 1 hour or more and 5 hours or less. The firing atmosphere is, for example, a nitrogen or inert gas atmosphere, but may also be a vacuum atmosphere. Alternatively, the vacuum atmosphere may be followed by an inert gas atmosphere. As a result, the multiple ceramic degreased bodies are sintered individually to form multiple SiC ceramic sintered bodies.

[0067] In the ceramic sintered body processing step, one or more SiC ceramic sintered bodies are processed as required to form multiple substrate precursors. The multiple substrate precursors include, for example, a substrate precursor that serves as a cover for the media flow path, a substrate precursor in which part of the media flow path is formed, and so on. For example, grooves that will become the media flow path after bonding are formed in one or more SiC ceramic sintered bodies. The media flow path may be formed by covering a groove formed in one substrate precursor with another substrate precursor (SiC ceramic sintered body). Alternatively, the media flow path may be formed by combining grooves formed in two substrate precursors. This method allows for the formation of media flow paths with various shapes.

[0068] In the substrate precursor bonding step, a plurality of substrate precursors are bonded to form a substrate. Bonding can be performed using either a bonding method that uses a bonding material or a bonding method that does not use a bonding material.

[0069] First, a bonding method using a bonding material will be described. First, a bonding material is prepared and applied to at least one end face of the substrate precursor on the bonding side. The end face of the substrate precursor on the bonding side is preferably polished to a surface roughness Ra of 1.6 μm or less, and more preferably to 0.4 μm or less. The thickness of the applied bonding material is preferably 5 μm or more and 30 μm or less.

[0070] Next, multiple substrate precursors are placed and heated while applying pressure perpendicular to the upper surface. The pressure is preferably 5 kPa or more. The heating temperature is preferably 1500°C or more and 1800°C or less. The heating time is preferably 0.5 hours or more and 5 hours or less. The heating atmosphere is, for example, a nitrogen or inert gas atmosphere, but may also be a vacuum atmosphere. This allows multiple substrate precursors to be bonded together to form a substrate having a media flow path inside.

[0071] The bonding material may be any material capable of bonding the substrate precursors together. For example, it may be a paste of mixed powder containing at least BC powder in SiC powder, which is the same main component as the substrate precursor. Alternatively, it may be a paste containing 90 wt% or more of SiC and, if necessary, containing Si or B to adjust the temperature at which it becomes molten during bonding.

[0072] Next, a bonding method that does not use a bonding material will be described. First, multiple substrate precursors are arranged. The end faces of the substrate precursors to be bonded are preferably polished to a surface roughness Ra of 0.1 μm or less. Next, the substrate precursors are heated while being pressed in a direction perpendicular to the upper surface. Among the bonding conditions, the pressure is preferably 4 MPa or more. The heating temperature is preferably 1600°C or more and 2000°C or less. The heating time is preferably 0.5 hours or more and 6 hours or less. The heating atmosphere is, for example, a nitrogen or inert gas atmosphere, but may also be a vacuum atmosphere. In this way, multiple substrate precursors can be bonded to form a substrate having a medium flow path therein.

[0073] In the above-described method, the substrate precursor is formed from a ceramic sintered body and then bonded to form the substrate, but the substrate precursor may also be formed from a ceramic calcined body and then bonded and sintered to form the substrate. Furthermore, when the structure of the media flow path or the like is simple, the substrate can also be produced by processing a ceramic degreased body, laminating it, and sintering it. When the structure of the media flow path or the like is complex, or when high dimensional accuracy of the media flow path or the like is required, the method of bonding ceramic sintered bodies is preferable.

[0074] In the substrate processing step, the outer shape of the substrate is processed. Furthermore, if necessary, for example, when terminals are used for electrical connection of the electrode-embedded member, through holes or the like for connecting the terminals are drilled. The drilling of through holes or the like may be performed before the substrate precursor bonding step.

[0075] In the metal film forming step, a metal film is formed on at least a part of the surface of the substrate. The thickness of the metal film is preferably 100 μm or more and 2000 μm or less, and more preferably 500 μm or more and 1400 μm or less.

[0076] The metal film is preferably formed by cold spraying. Cold spraying allows film formation at room temperature or relatively low temperatures and can prevent the metal film from peeling off from the substrate. Furthermore, the metal film is preferably composed primarily of Al with a purity of 97 wt% or higher or an Al alloy containing 70 wt% to 98.7 wt% Al. When a metal film composed primarily of Al or an Al alloy is formed by cold spraying, the thickness can be set within a wide range, for example, from 10 to 2000 μm. The electrical conductivity and CTE of the metal film can be adjusted by adjusting the purity of the raw material powder and the type and amount of filler. The film thickness may be adjusted depending on the type of raw material powder. Although the metal film can also be formed by thermal spraying, cold spraying is preferred for its denseness and adhesion.

[0077] When the ceramic sintered body forming the substrate contains SiC as a main component and the metal film is formed by cold spraying or thermal spraying, it is preferable to adjust the conditions of the cold spraying or thermal spraying and the thickness of the metal film so that the range of the aspect ratio A of the Al or Al alloy forming the metal film and the thickness T (μm) of the metal film satisfy the above formula (1) relative to the thermal expansion coefficient α1 (ppm / K) of the metal film, the thermal expansion coefficient α2 (ppm / K) of the substrate, and the Young's modulus E (GPa) of the substrate.

[0078] Before the metal film forming step, a step of forming a base metal film on at least a portion of the surface of the substrate may be performed. The base metal film can be formed by cold spraying, thermal spraying, CVD, vapor deposition, plating, or the like of a material containing a precious metal. Furthermore, after the metal film forming step, a step of forming an insulating layer on the metal film may be performed. The step of forming the insulating layer may be performed after joining the electrode-embedding member. The insulating layer can be formed, for example, by a thermal sprayed film of Al2O3.

[0079] (Method of manufacturing electrode-embedded member) When the electrode-embedded member of the substrate holder according to the embodiment of the present invention is formed of a ceramic sintered body, it is produced, for example, by a molded body hot pressing method described below. Note that the manufacturing method of the electrode-embedded member is not limited to this method, and may be, for example, a powder hot pressing method or a conventional green sheet lamination method.

[0080] The method for manufacturing an electrode-embedded member of a substrate holder according to an embodiment of the present invention by a molded body hot pressing method includes a ceramic molded body forming step, a ceramic degreased body preparing step, a firing step, and a ceramic sintered body processing step.

[0081] In the ceramic green body forming process, multiple ceramic green bodies are formed from ceramic raw material powder containing, for example, aluminum nitride (AlN) as the main component. Sintering aids may be added as needed. For example, AlN ceramic raw material powder is mixed with an appropriate amount of additives, such as a sintering aid Y2O3, a binder, a plasticizer, and a dispersant, to prepare a slurry, which is then granulated by a method such as spray drying. The granulated powder is then pressure-molded to form multiple ceramic green bodies.

[0082] The AlN ceramic raw material powder is preferably highly pure, preferably 96% or more, more preferably 99% or more, and even more preferably 99.9% or more. The average particle size of the AlN ceramic raw material powder is preferably 0.1 μm or more and 1.0 μm or less.

[0083] The mixing and molding methods are the same as those for the SiC ceramics described above. After molding, a groove may be formed on one side of the ceramic compact (the surface to be joined with another ceramic compact) in a shape that matches the shape of the electrode. The shape of the compact may be adjusted by machining. Machining may be performed after degreasing.

[0084] In the ceramic degreased body preparation process, a plurality of ceramic compacts are degreased at a predetermined temperature or higher for a predetermined time or longer to prepare a plurality of ceramic degreased bodies. The conditions for the ceramic degreased body preparation process are the same as those for the SiC ceramics described above.

[0085] The electrodes are prepared in shapes that correspond to the design and application of the substrate holder and the electrode-embedding member. The electrodes can be in various shapes, such as mesh or foil, and can be made of various materials, such as molybdenum or tungsten. The electrodes and multiple ceramic degreased bodies are combined to form a flat laminate with the electrodes embedded.

[0086] In the firing step, the formed laminate is subjected to uniaxial pressure firing or atmospheric pressure firing to form a ceramic sintered body. When uniaxial pressure firing is performed, the pressure is preferably 1 MPa or more. The firing temperature is preferably 1700°C or more and 2000°C or less. The firing time is preferably 1 hour or more and 12 hours or less, and more preferably 1 hour or more and 5 hours or less. The firing atmosphere is, for example, a nitrogen or inert gas atmosphere, but may also be a vacuum atmosphere. As a result, one or more degreased ceramic bodies are sintered to form an AlN ceramic sintered body.

[0087] In the ceramic sintered body processing step, the AlN ceramic sintered body is subjected to necessary processing such as processing the outer shape and drilling terminal holes to form an electrode-embedding member.

[0088] (Joining process) In the bonding process, an appropriate bonding method is selected depending on the material and CTE difference between the metal film and the electrode-embedded member of the fabricated substrate. The bonding method is bonding using a brazing material containing a metal such as In or Al, or bonding using an inorganic or organic adhesive. When a metal film is formed on one main surface of the substrate, the bonding method may be a method in which the metal film is used as a bonding layer.

[0089] When bonding using a brazing material, it is preferable that the surface roughness Ra of one main surface of the substrate or the bonding surface of the metal film and the bonding surface of the electrode-embedded member be 1.6 μm or less. Then, the brazing material is placed between the bonding surfaces of the metal film and the electrode-embedded member, and the bonding is performed by heating to the melting point or glass transition point of the brazing material. The brazing material may be a thin metal film.

[0090] When bonding is performed using an inorganic or organic adhesive, it is preferable that the surface roughness Ra of one main surface of the substrate or the bonding surface of the metal film and the bonding surface of the electrode-embedded member be 1.6 μm or less. The adhesive is then placed between the bonding surfaces of the metal film and the electrode-embedded member, and the bonding is performed by heating to the glass transition point of the adhesive. When using an adhesive, it is preferable that a filler be added to the adhesive to increase thermal conductivity.

[0091] When bonding is performed using a metal film formed on one main surface of the substrate as a bonding layer, the bonding surfaces of the metal film and the electrode-embedding member preferably have a surface roughness Ra of 0.2 μm or less, more preferably 0.1 μm or less. The bonding surfaces of the substrate and the electrode-embedding member are then brought together and bonded by applying a force of 1 MPa or more in a direction perpendicular to the bonding surfaces and heating to a temperature above −200° C., the melting point of the metal forming the metal film.

[0092] In this manner, the substrate holding member according to the embodiment of the present invention can be manufactured.

[0093] [Example] (Sample 1) Sample 1 is a ceramic component sample in which a metal film is formed on the entire surface of a substrate made of sintered SiC ceramics. The raw material for the substrate was SiC raw material powder (purity 99.9 wt%, average particle size 0.1 μm). 0.1 wt% of B4C and 0.5 wt% of C were added as sintering aids to the SiC raw material powder, and binders, dispersants, etc. were added and mixed appropriately to produce a slurry, which was then granulated by spray drying.

[0094] The granulated powder was then cold isostatically pressed into a circular compact with a diameter of 300 mm and a thickness of 30 mm, and a circular compact with a diameter of 300 mm and a thickness of 20 mm. Next, a groove with a width of 10 mm and a depth of 12 mm was formed on one side of the 30 mm thick sintered ceramic compact to form a media flow path that could be drawn in one stroke and was roughly concentric. The ceramic compact was then heat-treated in a furnace at 500°C for 12 hours to form a degreased ceramic compact.

[0095] Next, the ceramic sintered bodies were formed by firing in an atmospheric furnace. The firing temperature was 2000°C and the firing time was 3 hours. Next, the outer shapes of the two ceramic sintered bodies were processed. The two ceramic sintered bodies were then combined and heat-treated under conditions of 4 MPa uniaxial pressure, 2050°C firing time, and 3 hours to bond the ceramic sintered bodies and produce a substrate with a media flow path inside.

[0096] Next, a metal film was formed over the entire surface of the substrate using the cold spray method, with a design average film thickness of 100 μm. The surface of the ceramic member before film formation was processed so that the surface roughness Ra was 1.6 μm. The raw material powder for the cold spray was Al with a purity of 98.7 wt% and an average particle size of 45 μm. After preheating the substrate to 100°C, the spray pressure was adjusted to form the film. The aspect ratio at this time was 0.49. In this way, the ceramic member of Sample 1 was produced.

[0097] (Sample 2) The ceramic member of Sample 2 was produced under the same conditions as Sample 1, except that the designed average thickness of the metal film was set to 200 μm.

[0098] (Sample 3) The ceramic member of Sample 3 was produced under the same conditions as Sample 1, except that the designed average thickness of the metal film was set to 1200 μm.

[0099] (Sample 4) The ceramic member of Sample 4 was produced under the same conditions as Sample 1, except that the designed average thickness of the metal film was set to 1400 μm.

[0100] (Sample 5) For Sample 5, the cold spray conditions were changed. The aspect ratio of the Al forming the metal film was 0.33. The designed average thickness of the metal film was set to 1200 μm. Other than that, the ceramic member for Sample 5 was fabricated under the same conditions as Sample 1.

[0101] (Sample 6) The ceramic member of Sample 6 was produced under the same conditions as Sample 5, except that the designed average thickness of the metal film was set to 1400 μm.

[0102] (Sample 7) The ceramic member of Sample 7 was produced under the same conditions as Sample 1, except that the designed average thickness of the metal film was set to 1600 μm.

[0103] (Sample 8) For Sample 8, the raw material powder for the metal film was changed to Al alloy (Al-Si) powder containing 10 wt% Si and having an average particle size of 3 μm. The cold spray film formation conditions were the same as in Example 1. The aspect ratio of the Al alloy forming the metal film was 0.40. Other than that, the ceramic member for Sample 8 was produced under the same conditions as Sample 1.

[0104] (Sample 9) The ceramic member of Sample 9 was produced under the same conditions as Sample 8, except that the designed average thickness of the metal film was set to 150 μm.

[0105] (Sample 10) The ceramic member of Sample 10 was produced under the same conditions as Sample 8, except that the designed average thickness of the metal film was set to 200 μm.

[0106] (Sample 11) The ceramic member of Sample 11 was produced under the same conditions as Sample 8, except that the designed average thickness of the metal film was set to 1200 μm.

[0107] (Sample 12) The ceramic member of Sample 12 was produced under the same conditions as Sample 8, except that the designed average thickness of the metal film was set to 1400 μm.

[0108] (Sample 13) The ceramic member of Sample 13 was produced under the same conditions as Sample 8, except that the designed average thickness of the metal film was set to 1600 μm.

[0109] (Sample 14) For Sample 14, the cold spraying conditions were changed. The aspect ratio of the Al alloy forming the metal film was 0.25. The designed average thickness of the metal film was set to 1200 μm. Other than that, the ceramic member for Sample 14 was fabricated under the same conditions as Sample 8.

[0110] (Sample 15) The ceramic member of Sample 15 was produced under the same conditions as Sample 14, except that the designed average thickness of the metal film was set to 1400 μm.

[0111] (Sample 16) The ceramic member of Sample 16 was produced under the same conditions as Sample 14, except that the designed average thickness of the metal film was set to 1600 μm.

[0112] (Sample 17) The ceramic member of Sample 17 was produced under the same conditions as Sample 14, except that the designed average thickness of the metal film was set to 1800 μm.

[0113] (Sample 18) For Sample 18, the raw material powder for the metal film was changed to a mixed powder consisting of 70 wt% Al powder with an average particle size of 45 μm mixed with 30 wt% SiC powder with an average particle size of 10 μm as a filler. The cold spray deposition conditions were the same as for Sample 1. In this case, the aspect ratio of the Al forming the metal film was 0.49. The designed average film thickness of the metal film was 300 μm. Apart from that, the ceramic member for Sample 18 was fabricated under the same conditions as for Sample 1.

[0114] (Measurement of linear expansion coefficient) For the metal films of the ceramic members of Samples 1, 8, and 18, metal films with the same composition or the same composition but containing the same amount of filler were separately formed, and then samples for measuring linear expansion were prepared, and the linear expansion coefficient of the metal films was measured using a thermal expansion measuring device. In addition, the linear expansion coefficient of the substrate was measured using a test piece of Sample 1.

[0115] (Young's modulus measurement) Using the test piece of Sample 1, the Young's modulus of the substrate was measured by a method in accordance with JIS R 1602-1995 (Testing method for elastic modulus of fine ceramics).

[0116] (Aspect ratio measurement) For each ceramic member sample, a cut surface perpendicular to one of the main surfaces was polished, and the aspect ratio of the Al or Al alloy forming the metal film was measured by observing the SEM image.

[0117] (Bonding strength measurement) The bond strength between the ceramic member and the metal film of each sample was measured according to JIS H 8402:2004 (Test method for tensile adhesion strength of thermal spray coatings). A strength of 1 MPa or more but less than 4 MPa was judged as excellent (◯), and a strength of 4 MPa or more was judged as particularly excellent (◎).

[0118] FIG. 8 is a table showing the measured values ​​of the metal film and substrate of each sample and the value of formula (1). Samples 1 to 18 all had sufficient bonding strength. In particular, Samples 2, 3, 5 to 7, 9 to 12, 14 to 16, and 18, for which the value of formula (1) was in the range of 0.25 to 3.0, had high bonding strength. Therefore, it was confirmed that when the value of formula (1) was in the range of 0.25 to 3.0, the risk of peeling and the like could be sufficiently reduced even if the thickness of the metal film was increased.

[0119] As described above, the ceramic member or substrate holding member of the present invention can suppress peeling or warping of the electrode-embedded member from the ceramic member, resulting in a stable structure and enabling multi-functionalization according to various purposes. In addition, the ceramic member or substrate holding member can suppress peeling or warping of the electrode-embedded member from the ceramic member, resulting in a stable structure.

[0120] The present invention is not limited to the above-described embodiments, and various modifications and equivalents are included within the spirit and scope of the present invention. Furthermore, the structure, shape, number, position, size, etc. of the components shown in each drawing are for the convenience of explanation and may be changed as appropriate. [Explanation of symbols]

[0121] 100 Ceramic materials 110 Base material 112 One main surface 114 Side 116 Other main surface 118 Media flow path 120 Metal Film 122 Particles made of Al or Al alloy 124 Filler 130 Second metal film 140 Undercoat metal film 150 insulating layer 200 Substrate holding member 210 Electrode embedding member 212 Substrate mounting surface 218 Electrode 220 Bonding layer

Claims

1. A ceramic member, a substrate made of a ceramic sintered body; a metal film formed on at least a portion of the surface of the substrate, The ceramic member is characterized in that the metal film is mainly composed of Al having a purity of 97 wt % or more or an Al alloy containing Al in an amount of 70 wt % to 98.7 wt %.

2. The metal film is made of SiC, Al ２ O ３ 2. The ceramic member according to claim 1, wherein the ceramic member is a metal-based composite film containing at least one of alumina, diamond, and c-BN as a filler.

3. 2. The ceramic member according to claim 1, further comprising a base metal film containing a noble metal formed between the substrate and the metal film.

4. The ceramic sintered body contains SiC as a main component, When the thickness of the metal film is T (μm), the thermal expansion coefficient of the metal film is α1 (ppm / K), the thermal expansion coefficient of the substrate is α2 (ppm / K), the aspect ratio of Al or Al alloy forming the metal film is A, and the Young's modulus of the substrate is E (GPa), the following mathematical formula (1) is satisfied: 0.25≦(T×α1) ２ ×A ０．５ ) / {(α1-α2) ２ ×E}≦3.0・・・(1) The ceramic member according to any one of claims 1 to 3.

5. The ceramic member according to any one of claims 1 to 3, characterized in that the ceramic member further comprises a second metal film formed on at least a portion of the surface of the metal film, the second metal film containing Al with a purity of 97 wt% or more or a second Al alloy containing Al with a purity of 97 wt% or more.

6. The ceramic member according to any one of claims 1 to 3, a substrate-holding member having an electrode-embedded member bonded to one main surface of the ceramic member and having a substrate-mounting surface.

Images