Ceramic bonded body, electrostatic chuck device, and method for manufacturing ceramic bonded body

Abstract

The ceramic joint (1) of the present invention comprises: a pair of ceramic plates (2, 3) containing a conductive material; and a conductive layer (4) and an insulating layer (5) interposed between the pair of ceramic plates (2, 3), wherein the porosity at the interface between the pair of ceramic plates (2, 3) and the insulating layer (5) is less than 4%, and the ratio of the average primary particle size of the insulating material constituting the insulating layer (5) to the average primary particle size of the insulating material constituting the ceramic plates (2, 3) is greater than 1.

Description

Technical Field

[0001] The present invention relates to a ceramic joint body, an electrostatic chuck device and a method for manufacturing the ceramic joint body.

[0002] This application claims priority based on Japanese Patent Application No. 2020-015794 filed in Japan on January 31, 2020, the contents of which are incorporated herein by reference. Background Art

[0003] Conventionally, in semiconductor manufacturing processes for producing semiconductor devices such as ICs, LSIs, and VLSIs, plate-shaped samples such as silicon wafers are fixed to an electrostatic chuck member having an electrostatic chuck function by electrostatic adsorption and subjected to predetermined processing.

[0004] For example, when the plate-like sample is subjected to etching or the like in a plasma environment, the surface of the plate-like sample may become hot due to the heat of the plasma, causing problems such as cracking (digging) of the resist film on the surface.

[0005] To maintain the desired constant temperature of the plate-shaped sample, an electrostatic chuck device is used. The electrostatic chuck device comprises an electrostatic chuck component and a temperature-regulating base component. The temperature-regulating base component, which has a flow path formed within the metal component for circulating a temperature-control cooling medium, is bonded to the lower surface of the electrostatic chuck component using a silicone adhesive, thereby integrating the two components.

[0006] In this electrostatic chuck device, a temperature-regulating coolant circulates through the flow path of a temperature-regulating base member to perform heat exchange. Specifically, the temperature of a plate-shaped sample fixed to the upper surface of the electrostatic chuck member is maintained at a desired constant temperature while electrostatically adsorbing the sample, allowing various plasma treatments to be performed on the plate-shaped sample.

[0007] However, electrostatic chuck components of electrostatic chuck devices are required to have corrosion resistance, heat resistance, plasma resistance, and durability against thermal cycle loads. As components of electrostatic chuck devices that achieve these excellent properties, known electrostatic chuck components include an electrostatic chuck base formed of a composite dielectric ceramic obtained by adding a conductive material to an insulating ceramic material, an internal electrode embedded in the electrostatic chuck base, and a power supply terminal provided to connect to the internal electrode (see, for example, Patent Documents 1 and 2).

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Laid-Open No. 2003-152064

[0011] Patent Document 2: Japanese Patent Application Laid-Open No. 2007-051045 Summary of the Invention

[0012] Technical issues to be solved by the invention

[0013] Although the material of the internal electrode of the electrostatic chuck electrode built-in base described in Patent Documents 1 and 2 is not particularly limited, the material is a high-melting-point material with high conductivity, and can also be a composite sintered body containing an insulating ceramic material and a conductive high-melting-point material. The bonding surface between the composite dielectric ceramic of the electrostatic chuck substrate and the internal electrode is usually bonded after the surface is polished. Therefore, the conductive material is exposed on each surface of the bonding interface between the electrostatic chuck substrate and the internal electrode. Therefore, a conductive path is easily formed in the interface between the electrostatic chuck substrate and the internal electrode (conductive layer), and the insulation is reduced. Therefore, there is a technical problem of generating insulation breakdown (discharge) at the bonding interface between the composite dielectric ceramic and the internal electrode.

[0014] The present invention has been made in view of the above circumstances, and its object is to provide a ceramic bonded body that suppresses dielectric breakdown (discharge) at the bonding interface between a ceramic plate and a conductive layer, an electrostatic chuck device including the ceramic bonded body, and a method for manufacturing the ceramic bonded body.

[0015] Means for solving technical problems

[0016] In order to solve the above-mentioned technical problems, the first method of the present invention provides a ceramic assembly, which comprises: a pair of ceramic plates containing a conductive material; and a conductive layer and an insulating layer located between the pair of ceramic plates, the porosity at the interface between the pair of ceramic plates and the insulating layer is less than 4%, and the ratio of the average primary particle size of the insulating material constituting the insulating layer to the average primary particle size of the insulating material constituting the ceramic plates is greater than 1.

[0017] The first aspect of the present invention also preferably has the following features: Two or more of the following features may be combined with each other.

[0018] In one embodiment of the present invention, the conductive layer may be composed of a conductive material and an insulating material, and the insulating layer may be composed of an insulating material.

[0019] In one embodiment of the present invention, the average primary particle size of the insulating material constituting the insulating layer may be 1.6 μm or more and 10.0 μm or less.

[0020] In one embodiment of the present invention, the ceramic plate may be formed of a composite of aluminum oxide and silicon carbide.

[0021] In one embodiment of the present invention, the insulating material contained in the conductive layer and the insulating layer may be composed only of aluminum oxide.

[0022] In one embodiment of the present invention, the conductive material contained in the conductive layer may be at least one selected from the group consisting of Mo2C, Mo, WC, W, TaC, Ta, SiC, carbon black, carbon nanotubes, and carbon nanofibers.

[0023] A second aspect of the present invention provides an electrostatic chuck device comprising an electrostatic chuck member formed of ceramic and a temperature adjustment base member formed of metal joined via an adhesive layer, wherein the electrostatic chuck member comprises the ceramic bonded body according to one embodiment of the present invention.

[0024] A third embodiment of the present invention provides a method for manufacturing a ceramic joint body, comprising: preparing a first ceramic plate containing a conductive material and a second ceramic plate containing a conductive material; performing a grinding process or a polishing process on one surface of the first ceramic plate to set the arithmetic mean roughness (Ra) of the one surface of the first ceramic plate to be less than 0.25 μm; applying a conductive layer forming paste on the processed one surface of the first ceramic plate to form a conductive layer coating; applying an insulating layer forming paste on the processed one surface of the first ceramic plate to form an insulating layer coating; A process of grinding or polishing the one surface of the plate and setting the arithmetic mean roughness (Ra) of one surface of the second ceramic plate to be less than 0.25 μm; a process of stacking the second ceramic plate, the conductive layer coating and the insulating layer coating in such a manner that the surfaces of the conductive layer coating and the insulating layer coating on the side opposite to the surface in contact with the first ceramic plate are in contact with the processed one surface of the second ceramic plate; and a process of heating and pressurizing the stack including the first ceramic plate, the conductive layer coating, the insulating layer coating and the second ceramic plate in the thickness direction.

[0025] The manufacturing method of the third aspect can appropriately manufacture the ceramic bonded body of the first aspect.

[0026] Effects of the Invention

[0027] According to the present invention, it is possible to provide a ceramic bonded body that suppresses dielectric breakdown (discharge) at the bonding interface between a ceramic plate and a conductive layer, an electrostatic chuck device including the ceramic bonded body, and a method for manufacturing the ceramic bonded body. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic cross-sectional view showing an example of a ceramic bonded body according to a preferred embodiment of the present invention.

[0029] Figure 2 This is a schematic cross-sectional view showing an example of an electrostatic chuck device according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0030] Preferred examples of embodiments of the ceramic bonded body, the electrostatic chuck device, and the method for producing the ceramic bonded body of the present invention will be described.

[0031] In addition, the present embodiment is only specifically described for a better understanding of the purpose of the invention, and does not limit the present invention unless otherwise specified. Without departing from the scope of the present invention, the quantity, position, size, value, ratio, material, etc. can be changed, omitted, and added.

[0032] [Ceramic bonded body]

[0033] (First embodiment)

[0034] Below, for reference Figure 1 , while describing a preferred example of a ceramic bonded body according to an embodiment of the present invention.

[0035] In all the following drawings, the dimensions, ratios, etc. of the components may be appropriately changed in some cases to make the drawings easier to understand.

[0036] Figure 1 : is a schematic cross-sectional view showing a ceramic bonded body according to this embodiment. Figure 1 As shown, a ceramic bonded body 1 of this embodiment includes a pair of ceramic plates 2 and 3 containing a conductive material, and a conductive layer 4 and an insulating layer 5 interposed between the pair of ceramic plates 2 and 3 .

[0037] Hereinafter, the ceramic plate 2 will be referred to as a first ceramic plate 2 , and the ceramic plate 3 will be referred to as a second ceramic plate 3 .

[0038] like Figure 1 As shown, in the ceramic assembly 1, a first ceramic plate 2, a combination of a conductive layer 4 and an insulating layer 5, and a second ceramic plate 3 are stacked in this order from the bottom of the figure. That is, the ceramic assembly 1 is a joint body formed by integrating the first ceramic plate 2 and the second ceramic plate 3 via the conductive layer 4 and the insulating layer 5. In the figure, the insulating layer 5 is arranged on the periphery of the conductive layer 4. The interface between the conductive layer 4 and the insulating layer 5 is also in contact with the first ceramic plate 2 and the second ceramic plate 3 arranged above and below these layers.

[0039] like Figure 1As shown, pores 6 are present at the interface between the first ceramic plate 2 and the insulating layer 5 and at the interface between the second ceramic plate 3 and the insulating layer 5. The porosity at the interface between the first ceramic plate 2 and the insulating layer 5 and at the interface between the second ceramic plate 3 and the insulating layer 5 is 4% or less, preferably 3% or less. More preferably, it is 2% or less. If the porosity exceeds 4%, it is impossible to suppress the occurrence of insulation breakdown (discharge) at the bonding interface between the ceramic plates 2, 3 and the conductive layer 4. The lower limit of the porosity can be selected arbitrarily, but for example, it is preferably 0.1% or more, more preferably 0.3% or more, and more preferably 0.5% or more, but it is not limited to this example.

[0040] The method for measuring the porosity at the interface between the first ceramic plate 2 and the insulating layer 5 and the interface between the second ceramic plate 3 and the insulating layer 5 can be measured by the method described below. First, the ceramic joint body 1 is cut in the thickness direction. Then, a field emission scanning electron microscope (FE-SEM) (for example, a field emission scanning electron microscope manufactured by JEOL Ltd.) is used to observe the cut surface in the thickness direction of the first ceramic plate 2, the second ceramic plate 3 and the insulating layer 5. Then, an image analysis software (for example, image analysis software (Mac-View Version 4: manufactured by MOUNTECH Co., Ltd.)) is used to analyze the image of the cut surface and calculate the area of ​​the pores 6. Based on the obtained calculation results, the porosity (%) is calculated using the area of ​​the insulating layer 5 and the area of ​​the pores 6 according to the following formula (1). The measurement area of ​​the image can be set, for example, as follows.

[0041] Measurement area: 360 μm × 480 μm (area of ​​the insulating layer 5: 15 μm × 480 μm, area of ​​the ceramic plate 3: 345 μm × 480 μm)

[0042] The measurement region is a region where the second ceramic plate 3 and the insulating layer 5 are in contact with each other. Furthermore, the areas used in formula (1) can be the above-mentioned areas and the porosity confirmed by the above-mentioned areas.

[0043] Porosity = Area of ​​pores / (Area of ​​insulating layer + Area of ​​pores) × 100 (1)

[0044] The first ceramic plate 2, the second ceramic plate 3 and the insulating layer 5 are composed of an insulating material as described later. The ratio of the average primary particle size of the insulating material constituting the insulating layer 5 to the average primary particle size of the insulating material constituting the first ceramic plate 2 and the second ceramic plate 3 ((average primary particle size of the insulating material constituting the insulating layer 5) / (average primary particle size of the insulating material constituting the first ceramic plate 2 and the second ceramic plate 3)) is greater than 1, and preferably greater than 1.3. Furthermore, it is preferably greater than 2.2. If the ratio is less than 1, it is impossible to suppress the occurrence of insulation breakdown (discharge) at the bonding interface between the ceramic plates 2, 3 and the conductive layer 4. The upper limit of the ratio can be arbitrarily selected, for example, it can be less than 10, or less than 7, but it is not limited to these examples. For example, the ratio can be 2 to 6, 3 to 5, 4 to 8, etc.

[0045] The shapes of the overlapping surfaces of the first ceramic plate 2 and the second ceramic plate 3 are preferably the same. The shape of the ceramic plate can be arbitrarily selected, and may be, for example, circular, doughnut-shaped, quadrilateral, or rectangular, but is not limited to these examples.

[0046] The thickness of the first ceramic plate 2 and the second ceramic plate 3 is not particularly limited and can be arbitrarily selected and adjusted appropriately according to the application of the ceramic bonded body 1. For example, although 0.3 to 3.0 mm, 0.4 to 0.5 mm, and 0.5 to 1.5 mm are given as examples, the present invention is not limited to these examples. The thickness of the first ceramic plate 2 and the second ceramic plate 3 can be the same or different.

[0047] The first ceramic plate 2 and the second ceramic plate 3 have the same composition or the same main component. That is, the first ceramic plate 2 and the second ceramic plate 3 may have the same composition or different compositions. The first ceramic plate 2 and the second ceramic plate 3 are composed of a composite of an insulating substance and a conductive substance. The composite is preferably composed only of an insulating substance and a conductive substance. Although there is no particular limitation on the insulating substance contained in the first ceramic plate 2 and the second ceramic plate 3, for example, at least one selected from aluminum oxide (Al2O3), aluminum nitride (AlN), yttrium oxide (Y2O3), yttrium aluminum garnet (YAG), etc. can be cited. Furthermore, although the conductive material contained in the first ceramic plate 2 and the second ceramic plate 3 is not particularly limited, for example, at least one selected from silicon carbide (SiC), titanium oxide (TiO2), titanium nitride (TiN), titanium carbide (TiC), carbon (C), carbon nanotubes (CNT), carbon nanofibers, rare earth oxides, rare earth fluorides, etc. can be cited.

[0048] The proportion of the insulating substance in the composite can be arbitrarily selected, and is preferably 80 to 99% by mass, more preferably 85 to 98% by mass, but is not limited to these examples. For example, the proportion can be 80 to 95% by mass, or 83 to 90% by mass. The proportion of the conductive substance in the composite can be arbitrarily selected, and is preferably 1 to 20% by mass, or 2 to 15% by mass, but is not limited to these examples. The proportion can be, for example, 3 to 12% by mass, or 5 to 10% by mass.

[0049] The material (composite) of the first ceramic plate 2 and the second ceramic plate 3 preferably has a volume resistivity of 10 13 Ω·cm or more and 10 15 A material having a dielectric strength of approximately 100 Ω·cm or less, mechanical strength, and durability against corrosive gases and plasmas thereof. Examples of such materials include alumina (Al2O3) sintered bodies, aluminum nitride (AlN) sintered bodies, and alumina (Al2O3)-silicon carbide (SiC) composite sintered bodies. However, from the perspectives of dielectric properties at high temperatures, high corrosion resistance, plasma resistance, and heat resistance, alumina (Al2O3)-silicon carbide (SiC) composite sintered bodies are preferred.

[0050] The average primary particle size of the insulating material constituting the first ceramic plate 2 and the second ceramic plate 3 measured by the method described below is preferably 0.5 μm to 3.0 μm, more preferably 0.8 μm to 2.5 μm, and even more preferably 1.0 μm to 2.0 μm.

[0051] When the average primary particle size of the insulating material constituting the first ceramic plate 2 and the second ceramic plate 3 is 0.5 μm or more and 3.0 μm or less, the first ceramic plate 2 and the second ceramic plate 3 can be obtained to be dense and have high voltage resistance and durability.

[0052] The average primary particle size of the insulating material constituting the first ceramic plate 2 and the second ceramic plate 3 is measured by the following measuring method. A field emission scanning electron microscope (FE-SEM) (e.g., a field emission scanning electron microscope manufactured by JEOL Ltd.) is used to observe the cut surface in the thickness direction of the first ceramic plate 2 and the second ceramic plate 3. Then, for the observed cut surface, the average of the particle sizes of 200 particles of the insulating material is set as the average primary particle size by the intercept method. In addition, the primary particles of the insulating material observed by FE-SEM can be observed as equiaxed particles.

[0053] The conductive layer 4 is a layer that can be used as the following electrodes, for example: a plasma generating electrode for generating plasma by passing high-frequency power to perform plasma processing, an electrostatic chuck electrode for generating electric charge and fixing a plate-shaped sample by electrostatic adsorption force, and / or a heater electrode for heating a plate-shaped sample by passing electricity and generating heat, etc. The shape (shape of the conductive layer 4 when viewed from above (from the thickness direction)) and size (thickness or area of ​​the conductive layer 4 when viewed from above (from the thickness direction)) of the conductive layer 4 are not particularly limited and can be appropriately adjusted according to the purpose of the ceramic joint 1. The thickness of the conductive layer 4 can be, for example, 5 to 200 mm or 8 to 150 mm, but is not limited to these examples. The thickness can also be 10 to 100 μm. The shape of the conductive layer 4 can be arbitrarily selected, but for example, it can also be circular, donut-shaped, quadrilateral, rectangular, etc. when viewed from above.

[0054] The conductive layer 4 is composed of a conductive substance and an insulating substance. The conductive layer 4 is preferably a conductive composite material composed only of a conductive substance and an insulating substance.

[0055] The conductive material contained in the conductive layer 4 is preferably at least one selected from the group consisting of molybdenum carbide (Mo2C), molybdenum (Mo), tungsten carbide (WC), tungsten (W), tantalum carbide (TaC), tantalum (Ta), silicon carbide (SiC), carbon black, carbon nanotubes, and carbon nanofibers. By containing at least one conductive material selected from the group consisting of these substances in the conductive layer 4, the electrical conductivity of the conductive layer can be ensured.

[0056] The insulating material contained in the conductive layer 4 is not particularly limited, but examples thereof include at least one selected from the group consisting of aluminum oxide (Al2O3), aluminum nitride (AlN), yttrium oxide (Y2O3), and yttrium aluminum garnet (YAG). The insulating material contained in the conductive layer 4 is preferably the same as the insulating material of the first ceramic plate 2 and the second ceramic plate 3.

[0057] By making conductive layer 4 from a conductive and insulating material, the bonding strength with first ceramic plate 2 and second ceramic plate 3, as well as the mechanical strength of the electrode, is enhanced. By including aluminum oxide (Al2O3) as the insulating material in conductive layer 4, dielectric properties at high temperatures, high corrosion resistance, plasma resistance, and heat resistance are maintained.

[0058] The content ratio (blending ratio) of the conductive material and the insulating material in the conductive layer 4 is not particularly limited and can be appropriately adjusted according to the application of the ceramic joint 1 .

[0059] The proportion of the insulating material used in the conductive layer 4 can be arbitrarily selected. It is preferably 25 to 65% by mass, more preferably 35 to 55% by mass, relative to the total amount of the conductive material and the insulating material, but is not limited to these examples. For example, the proportion may be 30 to 60% by mass, 40 to 50% by mass, etc.

[0060] The proportion of the conductive material used in the conductive layer 4 can be arbitrarily selected, and is preferably 35-75% by mass, more preferably 45-65% by mass, relative to the total amount, but is not limited to these examples. For example, the proportion may be 40-70% by mass, 50-60% by mass, etc.

[0061] The insulating layer 5 is provided to bond the boundary between the first ceramic plate 2 and the second ceramic plate 3, i.e., the outer edge region outside the portion where the conductive layer 4 is formed. The shape of the insulating layer 5 (the shape of the insulating layer 5 when viewed from above (from the thickness direction)) is not particularly limited and can be appropriately adjusted according to the shape of the conductive layer 4.

[0062] In the ceramic bonded body 1 of this embodiment, the thickness of the insulating layer 5 is preferably equal to the thickness of the conductive layer 4. The shape of the insulating layer 5 can be arbitrarily selected, and may be, for example, circular, doughnut-shaped, quadrilateral, or rectangular when viewed from above, but is not limited to these examples. The insulating layer 5 may also be shaped so as to surround the conductive layer 4 when viewed from above.

[0063] The insulating layer 5 is composed only of an insulating material.

[0064] While the insulating material constituting the insulating layer 5 is not particularly limited, it is preferably the same as the insulating material constituting the first ceramic plate 2 and the second ceramic plate 3. Examples of the insulating material constituting the insulating layer 5 include at least one selected from the group consisting of aluminum oxide (Al2O3), aluminum nitride (AlN), yttrium oxide (Y2O3), and yttrium aluminum garnet (YAG). The insulating material constituting the insulating layer 5 is preferably composed solely of aluminum oxide (Al2O3). By using aluminum oxide (Al2O3) as the insulating material constituting the insulating layer 5, dielectric properties at high temperatures, high corrosion resistance, plasma resistance, and heat resistance are appropriately maintained.

[0065] The average primary particle size of the insulating material constituting insulating layer 5 is preferably 1.6 μm to 10.0 μm, more preferably 1.6 μm to 8.0 μm, and even more preferably 1.6 μm to 6.0 μm. These values ​​may also be 1.6 to 2.5 μm, 2.5 to 3.5 μm, or 3.5 to 5.0 μm.

[0066] If the average primary particle size of the insulating material constituting the insulating layer 5 is 1.6 μm or larger, sufficient withstand voltage can be obtained. On the other hand, if the average primary particle size of the insulating material constituting the insulating layer 5 is 10.0 μm or smaller, good workability such as grinding can be achieved.

[0067] The method for measuring the average primary particle size of the insulating material constituting the insulating layer 5 is the same as the method for measuring the average primary particle size of the insulating material constituting the first ceramic plate 2 and the second ceramic plate 3 .

[0068] According to the ceramic joint body 1 of this embodiment, it comprises: a pair of ceramic plates 2, 3, containing a conductive material; and a conductive layer 4 and an insulating layer 5, which are located between the ceramic plates 2, 3. The porosity at the interface between the ceramic plates 2, 3 and the insulating layer 5 is less than 4%, and the ratio of the average primary particle size of the insulating material constituting the insulating layer 5 to the average primary particle size of the insulating material constituting the ceramic plates 2, 3 is greater than 1, thereby being able to suppress the occurrence of insulation breakdown (discharge) at the joint interface between the ceramic plates 2, 3 and the conductive layer 4.

[0069] [Method for producing a ceramic bonded body]

[0070] The manufacturing method of the ceramic joint body of this embodiment comprises: a process of grinding or polishing one surface of a first ceramic plate containing a conductive material to set the arithmetic mean roughness (Ra) of one surface of the first ceramic plate to be less than 0.25 μm (hereinafter referred to as the “first process”); a process of applying a conductive layer forming paste to form a conductive layer coating film on one surface of the first ceramic plate subjected to the grinding or polishing process, and applying an insulating layer forming paste to form an insulating layer coating film (hereinafter referred to as the “second process”); grinding or polishing one surface of the second ceramic plate containing a conductive material The invention further comprises the following steps: a step of laminating the second ceramic plate in such a manner that the surface of the conductive layer coating and the insulating layer coating opposite to the surface in contact with the first ceramic plate is in contact with one surface of the second ceramic plate that has been ground or polished (hereinafter referred to as the "fourth step"); and a step of heating and pressing the laminate comprising the first ceramic plate, the conductive layer coating, the insulating layer coating and the second ceramic plate in the thickness direction.

[0071] The conductive layer is preferably in direct contact with and sandwiched between the pair of ceramic plates, and the insulating layer is preferably in direct contact with and sandwiched between the pair of ceramic plates.

[0072] Below, for reference Figure 1 , while describing the method for manufacturing the ceramic bonded body of this embodiment.

[0073] In the first step, at least one surface of the first ceramic plate 2, namely the surface 2a facing the insulating layer 5, is ground or polished to reduce the arithmetic mean roughness (Ra) of the surface 2a of the first ceramic plate 2 to 0.25 μm or less. The grinding and polishing conditions can be arbitrarily selected.

[0074] The arithmetic mean roughness (Ra) of one surface 2a of the first ceramic plate 2 is 0.25 μm or less, more preferably 0.23 μm or less, and even more preferably 0.20 μm or less. Furthermore, it is more preferably 0.1 μm or less. However, this is not limited to these examples. The lower limit can be arbitrarily selected, but for example, the arithmetic mean roughness (Ra) is 0.005 μm or more, preferably 0.01 μm or more, but this is not limited to these examples.

[0075] The arithmetic mean roughness (Ra) of one surface 2a of the first ceramic plate 2 is measured using a surface roughness meter (e.g., a stylus-type surface roughness meter manufactured by TOKYO SEIMITSU CO., LTD.) in accordance with JIS B 0601:2013 "Geometric Product Specification (GPS) - Surface Texture: Profile Method - Terms, Definitions and Surface Texture Parameters."

[0076] In order to set the arithmetic mean roughness (Ra) of the surface 2a of the first ceramic plate 2 to 0.25 μm or less, it is preferable to use abrasive grains of appropriately selected particle sizes during grinding or polishing. For example, the abrasive grains preferably have a particle size in the range of #200 to #4000 as indicated by JIS grit size.

[0077] In the second step, a conductive layer forming paste is applied to a predetermined position of the ground or polished surface 2a of the first ceramic plate 2 by an arbitrarily selected coating method such as screen printing to form a coating film (conductive layer coating film) to become the conductive layer 4.

[0078] As the conductive layer forming paste, it is preferable to use a paste obtained by dispersing a conductive substance and an insulating substance forming the conductive layer 4 in an arbitrarily selected solvent.

[0079] As the solvent contained in the conductive layer forming paste, isopropyl alcohol or the like is used. The ratio of the above substances in the conductive layer forming paste can be arbitrarily selected, but is preferably 10 to 40% by mass, and more preferably 20 to 30% by mass.

[0080] The average primary particle size of the conductive material is preferably 0.1 μm to 10 μm, more preferably 0.5 μm to 5 μm. The particle size can be, but is not limited to, 0.3 to 6 μm, 1 to 8 μm, or 2 to 4 μm, as needed. The average primary particle size of the insulating material is preferably 0.01 μm to 10 μm, more preferably 1.0 μm to 10 μm. The particle size can be, but is not limited to, 0.3 to 6 μm, 1 to 8 μm, or 2 to 4 μm, as needed.

[0081] In the second step, an insulating layer-forming paste is applied to a predetermined position on the ground or polished surface 2a of the first ceramic plate 2 by an arbitrarily selected coating method such as screen printing, thereby forming a coating film (insulating layer coating film) that will become the insulating layer 5. The insulating layer-forming paste and the conductive layer-forming paste may overlap, but preferably do not overlap. The insulating layer-forming paste and the conductive layer-forming paste may be formed side by side or in contact with each other.

[0082] As the insulating layer forming paste, it is preferable to use a paste obtained by dispersing an insulating substance forming the insulating layer 5 in an arbitrarily selected solvent.

[0083] As the solvent contained in the insulating layer forming paste, isopropyl alcohol or the like is used. The ratio of the above substances in the insulating layer forming paste can be arbitrarily selected, but is preferably 20 to 70% by mass, and more preferably 30 to 50% by mass.

[0084] Alternatively, the insulating layer forming paste may be applied first, the conductive layer forming paste may be applied first, or both may be applied simultaneously. The first applied paste may be applied after it has dried, or before it has dried.

[0085] In the third step, in the same manner as the first step, grinding or polishing is performed on at least one surface of the second ceramic plate 3, namely the surface 3a opposite to the insulating layer 5 or the conductive layer 4, so that the arithmetic mean roughness (Ra) of the surface 3a of the second ceramic plate 3 is set to be less than 0.25μm.

[0086] The arithmetic mean roughness (Ra) of the surface 3a of the second ceramic plate 3 is 0.25 μm or less, more preferably 0.23 μm or less, and even more preferably 0.20 μm or less. Furthermore, it is more preferably 0.1 μm or less. The lower limit can be arbitrarily selected, but for example, the arithmetic mean roughness (Ra) is 0.005 μm or more, preferably 0.01 μm or more, but is not limited to these examples.

[0087] The second and third steps may or may not include a drying step of drying the applied paste to a desired state.

[0088] In the fourth step, the second ceramic plate 3 is laminated so that the ground or polished surface 3 a of the second ceramic plate 3 contacts the surfaces of the conductive layer coating and the insulating layer coating opposite to the surfaces contacting the first ceramic plate 2 .

[0089] In the fifth step, the laminate comprising the first ceramic plate 2, the coating film serving as the conductive layer 4, the coating film serving as the insulating layer 5, and the second ceramic plate 3 is heated and pressurized in the thickness direction. The environment in which the laminate is heated and pressurized in the thickness direction is preferably a vacuum or an inert atmosphere such as Ar, He, or N2.

[0090] The temperature for heating the laminate (heat treatment temperature) can be arbitrarily selected, but is preferably 1600°C to 1900°C, more preferably 1650°C to 1850°C. Alternatively, it may be 1700°C to 1800°C. When the laminate is heated to a temperature of 1600°C to 1900°C, the solvent contained in each coating film can be volatilized, allowing the conductive layer 4 and the insulating layer 5 to be appropriately formed between the first ceramic plate 2 and the second ceramic plate 3. Furthermore, the first ceramic plate 2 and the second ceramic plate 3 can be appropriately bonded and integrated via the conductive layer 4 and the insulating layer 5.

[0091] The pressure (pressing force) for pressing the laminate in the thickness direction can be arbitrarily selected, but is preferably 1.0 MPa to 50.0 MPa, more preferably 3.0 MPa to 35.0 MPa, and even more preferably 5.0 MPa to 20.0 MPa.

[0092] When the pressure applied to the laminate in the thickness direction is 1.0 MPa or more and 50.0 MPa or less, a conductive layer 4 and an insulating layer 5 that adhere closely to each other can be appropriately formed between the first ceramic plate 2 and the second ceramic plate 3. Furthermore, the first ceramic plate 2 and the second ceramic plate 3 can be appropriately bonded and integrated via the conductive layer 4 and the insulating layer 5.

[0093] [Electrostatic chuck device]

[0094] Below, for reference Figure 2 , while describing an electrostatic chuck device according to one embodiment of the present invention.

[0095] Figure 2 1 is a schematic cross-sectional view showing an example of an electrostatic chuck device according to this embodiment. Figure 2 In, with Figure 1 The same components of the ceramic bonded body shown are denoted by the same reference numerals, and redundant descriptions are omitted.

[0096] like Figure 2As shown, the electrostatic chuck device 100 of this embodiment includes a disk-shaped electrostatic chuck member 102; a disk-shaped temperature-adjusting base member 103 for adjusting the electrostatic chuck member 102 to a desired temperature; and an adhesive layer 104 for integrally bonding the electrostatic chuck member 102 and the temperature-adjusting base member 103. In the electrostatic chuck device 100 of this embodiment, the electrostatic chuck member 102 is formed, for example, from the ceramic bonded body 1 of the above-described embodiment. Here, the case where the electrostatic chuck member 102 is formed from the ceramic bonded body 1 will be described.

[0097] In the following description, the relative positions of the components are sometimes indicated by referring to the placement surface 111 a side of the placement plate 111 as “upper” and the temperature adjustment base member 103 side as “lower”.

[0098] [Electrostatic chuck components]

[0099] The electrostatic chuck component 102 includes: a loading plate 111, the upper surface of which is provided as a loading surface 111a for loading plate-shaped samples such as semiconductor chips and is formed of ceramic; a supporting plate 112, provided on the surface side of the loading plate 111 opposite to the loading surface 111a; an electrostatic adsorption electrode 113, sandwiched between these loading plates 111 and the supporting plate 112; an annular insulating material 114, sandwiched by the loading plate 111 and the supporting plate 112 and surrounding the electrostatic adsorption electrode 113; and a power supply terminal 116, provided in a fixing hole 115 of the temperature adjustment base component 103 in a manner connected to the electrostatic adsorption electrode 113.

[0100] In the electrostatic chuck component 102, the mounting plate 111 can be equivalent to the above-mentioned second ceramic plate 3, the support plate 112 can be equivalent to the above-mentioned first ceramic plate 2, the electrostatic adsorption electrode 113 can be equivalent to the above-mentioned conductive layer 4, and the insulating material 114 can be equivalent to the above-mentioned insulating layer 5.

[0101] [Loading plate]

[0102] A plurality of protrusions (not shown) for supporting plate-shaped samples such as semiconductor wafers are appropriately erected on the loading surface 111a of the loading plate 111 (the second ceramic plate 3). Furthermore, an annular protrusion having a square cross-section can be provided around the peripheral edge of the loading surface 111a of the loading plate 111 to prevent leakage of cooling gases such as helium (He). Furthermore, a plurality of protrusions having the same height as the annular protrusion and having a circular cross-section and a roughly rectangular longitudinal section can be provided in the area surrounded by the annular protrusion on the loading surface 111a. In this way, the loading plate 111 can be appropriately processed.

[0103] The thickness of the mounting plate 111 can be arbitrarily selected, but is preferably 0.3 mm to 3.0 mm, more preferably 0.4 mm to 2.5 mm, and even more preferably 0.5 mm to 1.5 mm. If the thickness of the mounting plate 111 is 0.3 mm or greater, excellent voltage resistance is achieved. On the other hand, if the thickness of the mounting plate 111 is 3.0 mm or less, the electrostatic adsorption force of the electrostatic chuck component 102 is not reduced, and the thermal conductivity between the plate-like sample placed on the mounting surface 111 a of the mounting plate 111 and the temperature adjustment base component 103 is not reduced, thereby maintaining the temperature of the plate-like sample being processed at a preferred constant temperature.

[0104] [Support plate]

[0105] The support plate 112 (first ceramic plate 2 ) supports the placement plate 111 and the electrostatic attraction electrode 113 from below.

[0106] The thickness of the support plate 112 is preferably 0.3 mm or more and 3.0 mm or less, more preferably 0.4 mm or more and 2.5 mm or less, and even more preferably 0.5 mm or more and 1.5 mm or less. If the thickness of the support plate 112 is 0.3 mm or more, sufficient voltage resistance can be ensured. On the other hand, if the thickness of the support plate 112 is 3.0 mm or less, the electrostatic adsorption force of the electrostatic chuck component 102 will not be reduced, and the thermal conductivity between the plate-shaped sample placed on the mounting surface 111a of the mounting plate 111 and the temperature adjustment base component 103 will not be reduced, thereby maintaining the temperature of the plate-shaped sample being processed at a preferred constant temperature.

[0107] [Electrode for electrostatic adsorption]

[0108] In the electrostatic attraction electrode 113 (conductive layer 4 ), an electrostatic attraction force for holding the plate-shaped sample on the placement surface 111 a of the placement plate 111 is generated by applying a voltage.

[0109] The thickness of the electrostatic adsorption electrode 113 can be arbitrarily selected, but is preferably 5 μm or more and 200 μm or less, more preferably 8 μm or more and 150 μm or less, and even more preferably 10 μm or more and 100 μm or less. Alternatively, it may be 20 μm or more and 80 μm or 40 μm or more and 60 μm or less. If the thickness of the electrostatic adsorption electrode 113 is 5 μm or more, sufficient electrical conductivity can be ensured. On the other hand, if the thickness of the electrostatic adsorption electrode 113 is 200 μm or less, the thermal conductivity between the plate sample placed on the mounting surface 111a of the mounting plate 111 and the temperature adjustment base member 103 is not reduced, and the temperature of the plate sample being processed can be maintained at a desired constant temperature. Furthermore, plasma permeability is not reduced, and plasma can be stably generated.

[0110] [Insulation material]

[0111] The insulating material 114 (insulating layer 5 ) surrounds the electrostatic attraction electrode 113 to protect the electrostatic attraction electrode 113 from corrosive gas and its plasma.

[0112] The placement plate 111 and the support plate 112 are integrally bonded to each other via the electrostatic attraction electrodes 113 through the insulating material 114 .

[0113] [Power supply terminal]

[0114] The power supply terminal 116 is used to apply a voltage to the electrostatic attraction electrode 113 .

[0115] The number and shape of the power supply terminals 116 are arbitrarily determined according to the form of the electrostatic attraction electrode 113 , that is, whether it is a monopolar type or a bipolar type.

[0116] The material of the power supply terminal 116 is not particularly limited as long as it is a conductive material with excellent heat resistance. The material of the power supply terminal 116 is preferably a material having a thermal expansion coefficient close to that of the electrostatic adsorption electrode 113 and the support plate 112. For example, metal materials such as Kovar and niobium (Nb) or various conductive ceramics are preferably used.

[0117] [Conductive adhesive layer]

[0118] The conductive adhesive layer 117 is provided in the fixing hole 115 of the temperature adjustment base member 103 and in the through hole 118 of the support plate 112. The conductive adhesive layer 117 is interposed between the electrostatic attraction electrode 113 and the power supply terminal 116 to electrically connect the electrostatic attraction electrode 113 and the power supply terminal 116.

[0119] The conductive adhesive constituting the conductive adhesive layer 117 can be arbitrarily selected, but preferably contains a conductive substance such as carbon fiber or metal powder, and a resin.

[0120] The resin contained in the conductive adhesive can be selected arbitrarily without particular limitation as long as it is a resin that is less likely to undergo cohesive failure due to thermal stress, and examples thereof include silicone resins, acrylic resins, epoxy resins, phenolic resins, polyurethane resins, and unsaturated polyester resins.

[0121] Among these, silicone resins are preferably used from the viewpoint of high elasticity and low cohesion failure due to thermal stress changes.

[0122] [Temperature adjustment base member]

[0123] The temperature adjustment base member 103 is a thick, disc-shaped member formed from at least one of metal and ceramic. The frame of the temperature adjustment base member 103 also serves as an internal electrode for plasma generation. A flow path 121 is formed within the frame of the temperature adjustment base member 103, through which a cooling medium such as water, He gas, or N₂ gas circulates.

[0124] The frame of the temperature adjustment base member 103 is connected to an external high-frequency power source 122. Furthermore, a power supply terminal 116, surrounded by insulating material 123, is fixed to the fixing hole 115 of the temperature adjustment base member 103 via insulating material 123. The power supply terminal 116 is connected to an external DC power source 124.

[0125] The material constituting the temperature adjustment base member 103 is not particularly limited as long as it is a metal or a composite material containing these metals with excellent thermal conductivity, electrical conductivity, and workability. Examples of materials suitable for constituting the temperature adjustment base member 103 include aluminum (Al), copper (Cu), stainless steel (SUS), and titanium (Ti).

[0126] Preferably, at least the surface of the temperature adjustment base member 103 exposed to plasma is treated with an aluminum oxide film or coated with a polyimide resin. More preferably, the entire surface of the temperature adjustment base member 103 is treated with the aluminum oxide film or coated with the resin.

[0127] By applying an alumina film treatment or resin coating to the temperature adjustment base member 103, the plasma resistance of the temperature adjustment base member 103 is improved, and abnormal discharge can be prevented. This improves the plasma resistance stability of the temperature adjustment base member 103 and prevents surface damage to the temperature adjustment base member 103.

[0128] [Adhesive layer]

[0129] The adhesive layer 104 is a layer that bonds and integrates the electrostatic chuck portion 102 and the cooling base portion 103 .

[0130] The thickness of the adhesive layer 104 can be arbitrarily selected, but is preferably 100 μm or more and 200 μm or less, and more preferably 130 μm or more and 170 μm or less.

[0131] When the thickness of adhesive layer 104 is within the above range, sufficient bonding strength can be maintained between electrostatic chuck portion 102 and cooling base portion 103 , and sufficient thermal conductivity can be ensured between electrostatic chuck portion 102 and cooling base portion 103 .

[0132] The material of the adhesive layer 104 can be arbitrarily selected, and is formed of, for example, a cured product obtained by heating and curing a silicone resin composition, an acrylic resin, an epoxy resin, or the like.

[0133] The silicone resin composition is a silicon compound having a siloxane bond (Si—O—Si) and is a resin excellent in heat resistance and elasticity, and therefore is more preferred.

[0134] As such a silicone resin composition, a silicone resin having a thermal curing temperature of 70° C. to 140° C. is particularly preferred.

[0135] Here, if the thermal curing temperature is lower than 70°C, when the electrostatic chuck portion 102 and the cooling base portion 103 are bonded in an opposed state, curing may not proceed sufficiently during the bonding process, potentially deteriorating workability. On the other hand, if the thermal curing temperature exceeds 140°C, the thermal expansion difference between the electrostatic chuck portion 102 and the cooling base portion 103 becomes large, increasing stress between the electrostatic chuck portion 102 and the cooling base portion 103, potentially causing separation between them. This is also undesirable.

[0136] According to the electrostatic chuck device 100 of the present embodiment, since the electrostatic chuck member 102 is formed of the ceramic bonded body 1 , it is possible to suppress the occurrence of dielectric breakdown (discharge) in the electrostatic chuck member 102 .

[0137] Hereinafter, a method for manufacturing the electrostatic chuck device according to this embodiment will be described.

[0138] An electrostatic chuck component 102 composed of the ceramic bonded body 1 obtained in the above manner is prepared.

[0139] An adhesive made of a silicone resin composition is applied to a predetermined region of one main surface 103a of the cooling base 103. The amount of adhesive applied is adjusted so that the electrostatic chuck 102 and the cooling base 103 can be integrally bonded.

[0140] Examples of a method for applying the adhesive include manual application using a doctor blade or the like, a bar coating method, a screen printing method, and the like.

[0141] After an adhesive is applied to one main surface 103 a of the cooling base 103 , the electrostatic chuck portion 102 (ceramic bonded body 1 ) and the cooling base 103 coated with the adhesive are stacked.

[0142] Then, the upright power supply terminal 116 is inserted and fitted into the fixing hole 115 bored in the cooling base portion 103 .

[0143] Next, the electrostatic chuck portion 102 is pressed against the cooling base portion 103 with a predetermined pressure, thereby integrally bonding the electrostatic chuck portion 102 and the cooling base portion 103. Thus, the electrostatic chuck portion 102 and the cooling base portion 103 are integrally bonded via the adhesive layer 104.

[0144] In this manner, the electrostatic chuck device 100 of the present embodiment can be obtained, in which the electrostatic chuck portion 102 and the cooling base portion 103 are bonded and integrated via the adhesive layer 104 .

[0145] Furthermore, the plate-shaped sample used in this embodiment is not limited to semiconductor wafers. For example, it can be a glass substrate for a flat panel display (FPD), such as a liquid crystal display (LCD), a plasma display panel (PDP), or an organic EL display. Furthermore, the electrostatic chuck device of this embodiment can be designed according to the shape and size of the substrate.

[0146] Example

[0147] Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[0148] [Example 1]

[0149] "Production of Ceramic Bonded Bodies"

[0150] A mixed powder of 91 mass% alumina powder and 9 mass% silicon carbide powder is prepared, molded, and sintered to produce ceramic plates (the first ceramic plate and the second ceramic plate) consisting of a disc-shaped alumina-silicon carbide composite sintered body (a composite of alumina and silicon carbide) with a diameter of 450 mm and a thickness of 5.0 mm.

[0151] One surface of the first ceramic plate (the surface in contact with the insulating layer) was polished to a value of 0.2 μm in terms of its arithmetic mean roughness (Ra). Furthermore, one surface of the second ceramic plate (the surface in contact with the insulating layer) was polished to a value of 0.2 μm in terms of its arithmetic mean roughness (Ra).

[0152] Next, a conductive layer forming paste is applied to the one surface of the first ceramic plate by screen printing to form a conductive layer coating. Furthermore, an insulating layer forming paste is applied to the one surface of the first ceramic plate by screen printing to form an insulating layer coating. The insulating layer coating and the conductive layer coating are formed in a non-overlapping manner. Furthermore, the shape of the conductive layer coating when viewed from above is set to be circular. The shape of the insulating layer coating is formed to surround the outer periphery of the conductive layer. The outer periphery of the insulating layer is set to be equal to the outer periphery of the first ceramic plate. That is, they are formed so that their outer peripheries are consistent when viewed from above. Furthermore, the thickness is set to be the same as the thickness of the conductive layer coating.

[0153] A paste containing aluminum oxide powder and molybdenum carbide powder dispersed in isopropyl alcohol was used as the conductive layer paste. The aluminum oxide powder content in the conductive layer paste was set to 25% by mass, and the molybdenum carbide powder content was set to 25% by mass. A paste containing aluminum oxide powder with an average primary particle size of 2.0 μm dispersed in isopropyl alcohol was used as the insulating layer paste. The aluminum oxide powder content in the insulating layer paste was set to 50% by mass.

[0154] Next, a second ceramic plate is laminated so that the surfaces of the conductive layer coating and the insulating layer coating opposite to the surfaces in contact with the first ceramic plate come into contact with one surface of the ground or polished second ceramic plate.

[0155] Next, the laminate consisting of the first ceramic plate, the conductive coating layer, the insulating coating layer, and the second ceramic plate was heated and pressed in the thickness direction under an argon atmosphere. The heat treatment temperature was set at 1700°C, the pressure was set at 10 MPa, and the heat treatment and pressing time was set at 2 hours.

[0156] Through the above process, we obtained Figure 1 The ceramic bonded body of Example 1 is shown.

[0157] (Porosity Measurement)

[0158] In the obtained ceramic bonded body, the porosity at the interface between the first ceramic plate and the insulating layer and the interface between the second ceramic plate and the insulating layer were measured. The results are shown in Table 1.

[0159] The porosity at the interface between the first ceramic plate and the insulating layer and the interface between the second ceramic plate and the insulating layer was measured as follows. The cut surfaces in the thickness direction of the first ceramic plate, the second ceramic plate, and the insulating layer were observed using a field emission scanning electron microscope (FE-SEM) manufactured by JEOL Ltd., and the images of the cut surfaces were analyzed using image analysis software (Mac-View Version 4: manufactured by MOUNTECH Co., Ltd.) to calculate the area of ​​the pores. In addition, the area and conditions used in the analysis were set to 360 μm × 480 μm (insulating layer 5: 15 μm × 480 μm, area of ​​ceramic plate 3: 345 μm × 480 μm). In addition, the measurement area is the area where the second ceramic plate 3 and the insulating layer 5 are in contact with each other.

[0160] From the obtained calculation results, the porosity (%) was calculated according to the following formula (1) using the area of ​​the insulating layer and the area of ​​the pores.

[0161] Porosity = Area of ​​pores / (Area of ​​insulating layer + Area of ​​pores) × 100 (1)

[0162] (Measurement of Average Primary Particle Size of Insulating Substances)

[0163] In the obtained ceramic joint body, the average primary particle size of the Al2O3 particles constituting the first ceramic plate and the second ceramic plate was measured. In addition, the average primary particle size of the insulating material constituting the insulating layer (recorded as "the average primary particle size of the Al2O3 powder (particles)" in Table 1) was measured and found to be 2.0 μm. Furthermore, the ratio of the average primary particle size of the Al2O3 particles constituting the insulating layer to the average primary particle size of the Al2O3 particles constituting the first ceramic plate and the second ceramic plate (recorded as "the ratio of the average primary particle size of the Al2O3 powder (particles)" in Table 1) was calculated and found to be 1.3. The results are shown in Table 1.

[0164] In addition, the Al2O3 average primary particle size of the particles constituting the 1st ceramic plate and the 2nd ceramic plate and the Al2O3 average primary particle size of the particles constituting the insulating layer were measured as follows. The resulting ceramic bonded body was cut. Then, a field emission scanning electron microscope (FE-SEM) manufactured by JEOL Ltd. was used to observe the cut surface of the thickness direction of the 1st ceramic plate and the 2nd ceramic plate, and the average of the particle diameters of 200 insulating materials was set to average primary particle size by the intercept method. In the above-mentioned observation, the insulating material, i.e., Al2O3, contained in the ceramic plate or the insulating layer can be observed. Particles can also be obtained by observation and calculation.

[0165] (Insulation evaluation)

[0166] The insulation properties of the ceramic bonded bodies were evaluated as follows.

[0167] Carbon tape was attached to the side surfaces of the ceramic bonded body (the side surfaces in the thickness direction of the ceramic bonded body) so as to contact the first ceramic plate, the insulating layer, and the second ceramic plate. The conductive layer was surrounded by the insulating layer and therefore not in contact with the carbon tape.

[0168] The first ceramic plate is penetrated in the thickness direction to form a through electrode extending from the surface of the first ceramic plate opposite to the surface in contact with the conductive layer to the conductive layer. The through electrode is provided in contact with the conductive layer.

[0169] Voltage was applied to the ceramic bonded structure through the carbon tape and through the electrodes, and the voltage at which dielectric breakdown (discharge) occurred was measured. Specifically, RF voltage was applied at 3000V for 10 minutes, followed by gradual application of 500V increments for 10 minutes. Dielectric breakdown was considered to have occurred when the measured current exceeded 0.1mA (milliamperes). The results are shown in Table 1.

[0170] [Example 2]

[0171] A ceramic bonded body of Example 2 was obtained in the same manner as in Example 1 except that the arithmetic mean roughness (Ra) of one surface of the first ceramic plate and one surface of the second ceramic plate was set to 0.07 μm.

[0172] The porosity and the average primary particle size of the Al2O3 particles of the ceramic bonded body of Example 2 were measured and the insulation properties were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0173] [Example 3]

[0174] A ceramic bonded body of Example 3 was obtained in the same manner as in Example 1 except that the arithmetic mean roughness (Ra) of one surface of the first ceramic plate and one surface of the second ceramic plate was set to 0.01 μm.

[0175] The porosity and the average primary particle size of the Al2O3 particles of the ceramic bonded body of Example 3 were measured and the insulation properties were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0176] [Example 4]

[0177] A mixed powder of 95.5 mass % alumina powder and 4.5 mass % silicon carbide powder was molded and sintered to produce ceramic plates (first ceramic plate and second ceramic plate) consisting of a disk-shaped alumina-silicon carbide composite sintered body with a diameter of 450 mm and a thickness of 5.0 mm.

[0178] The ceramic joint body of Example 4 was obtained in the same manner as Example 1, except that the average primary particle size of the Al2O3 particles constituting the insulating layer was set to 3.0 μm and the ratio of the average primary particle size of the Al2O3 particles constituting the insulating layer to the average primary particle size of the Al2O3 particles constituting the first ceramic plate and the second ceramic plate was set to 2.0.

[0179] The porosity and the average primary particle size of the Al2O3 particles of the ceramic bonded body of Example 4 were measured and the insulation properties were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0180] [Example 5]

[0181] The average primary particle size of the Al2O3 particles constituting the insulating layer is set to 3.3 μm, and the ratio of the average primary particle size of the Al2O3 particles constituting the insulating layer to the average primary particle size of the Al2O3 particles constituting the first ceramic plate and the second ceramic plate is set to 2.2. The heat treatment temperature of the stack including the first ceramic plate, the conductive layer coating, the insulating layer coating and the second ceramic plate is set to 1750°C. Except for this, the ceramic joint body of Example 5 is obtained in the same manner as in Example 4.

[0182] The porosity and the average primary particle size of the Al2O3 particles of the ceramic bonded body of Example 5 were measured and the insulation properties were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0183] [Example 6]

[0184] The average primary particle size of the Al2O3 particles constituting the insulating layer is set to 5.8 μm, and the ratio of the average primary particle size of the Al2O3 particles constituting the insulating layer to the average primary particle size of the Al2O3 particles constituting the first ceramic plate and the second ceramic plate is set to 3.9. The heat treatment temperature of the stack including the first ceramic plate, the conductive layer coating, the insulating layer coating and the second ceramic plate is set to 1800°C. Except for this, the ceramic joint body of Example 6 is obtained in the same manner as in Example 4.

[0185] The porosity and the average primary particle size of the Al2O3 particles of the ceramic bonded body of Example 6 were measured and the insulation properties were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0186] [Comparative Example 1]

[0187] A ceramic bonded body of Comparative Example 1 was obtained in the same manner as in Example 1 except that the arithmetic mean roughness (Ra) of one surface of the first ceramic plate and one surface of the second ceramic plate was set to 0.3 μm.

[0188] The porosity and the average primary particle size of the Al 2 O 3 particles of the ceramic bonded body of Comparative Example 1 were measured and the insulation properties were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0189] [Comparative Example 2]

[0190] The average primary particle size of the Al2O3 particles constituting the insulating layer is set to 1.5 μm, and the ratio of the average primary particle size of the Al2O3 particles constituting the insulating layer to the average primary particle size of the Al2O3 particles constituting the first ceramic plate and the second ceramic plate is set to 1.0. The heat treatment temperature of the stack including the first ceramic plate, the conductive layer coating, the insulating layer coating and the second ceramic plate is set to 1650°C. Except for this, a ceramic joint body of Comparative Example 2 is obtained in the same manner as in Example 1.

[0191] The porosity and the average primary particle size of the Al2O3 particles of the ceramic bonded body of Comparative Example 2 were measured and the insulation properties were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0192] [Comparative Example 3]

[0193] The average primary particle size of the Al2O3 particles constituting the insulating layer is set to 1.0 μm, and the ratio of the average primary particle size of the Al2O3 particles constituting the insulating layer to the average primary particle size of the Al2O3 particles constituting the first ceramic plate and the second ceramic plate is set to 0.7. The heat treatment temperature of the stack including the first ceramic plate, the conductive layer coating, the insulating layer coating and the second ceramic plate is set to 1600°C. Except for this, a ceramic joint body of Comparative Example 3 is obtained in the same manner as in Example 1.

[0194] The porosity and the average primary particle size of the Al 2 O 3 particles of the ceramic bonded body of Comparative Example 3 were measured and the insulation properties were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0195] [Table 1]

[0196]

[0197] The results in Table 1 show that the dielectric strength of the ceramic bonded body of Comparative Example 1 having a porosity of 4.5% (exceeding 4%) is low, but the dielectric strength of the ceramic bonded bodies of Examples 1 to 6 having a porosity of 3.0% or less is high.

[0198] Furthermore, it can be seen that the ceramic assemblies of Comparative Examples 2 and 3, in which the ratio of the average primary particle size of the Al2O3 particles constituting the insulating layer to the average primary particle size of the Al2O3 particles constituting the ceramic plate is 1.0 or less, have low dielectric strength voltages. In contrast, the ceramic assemblies of Examples 1 to 6, in which the ratio of the average primary particle size of the Al2O3 particles constituting the insulating layer to the average primary particle size of the Al2O3 particles constituting the ceramic plate exceeds 1, have high dielectric strength voltages.

[0199] Industrial applicability

[0200] The present invention provides a ceramic assembly, an electrostatic chuck device, and a method for manufacturing the ceramic assembly that suppress dielectric breakdown (discharge) at the interface between a ceramic plate and a conductive layer. In the ceramic assembly of the present invention, the porosity at the interface between a pair of ceramic plates and the insulating layer is less than 4%, and the ratio of the average primary particle size of the insulating material constituting the insulating layer to the average primary particle size of the insulating material constituting the ceramic plate is greater than 1. Therefore, dielectric breakdown (discharge) is suppressed at the interface between the ceramic plate and the conductive layer. Therefore, the ceramic assembly of the present invention can be suitably used in an electrostatic chuck component of an electrostatic chuck device, and its usefulness is very great.

[0201] Description of labels

[0202] 1-Ceramic joint

[0203] 2-Ceramic plate (1st ceramic plate)

[0204] 2a- One surface of the first ceramic plate

[0205] 3-Ceramic plate (second ceramic plate)

[0206] 3a- One surface of the second ceramic plate

[0207] 4-Conductive layer

[0208] 5-Insulation layer

[0209] 6-Stomach

[0210] 100-Electrostatic chuck device

[0211] 102-Electrostatic chuck components

[0212] 103- Temperature adjustment base component (cooling base)

[0213] 103a-One main surface of the cooling base

[0214] 104-adhesive layer

[0215] 111-Loading plate

[0216] 111a- Loading surface of the loading plate

[0217] 112-Support plate

[0218] 113-Electrode for electrostatic adsorption

[0219] 114-Insulation Materials

[0220] 115-Fixing hole

[0221] 116-Power supply terminal

[0222] 117-Conductive adhesive layer

[0223] 118-Through hole

[0224] 121-Flow path

[0225] 122-High Frequency Power Supply

[0226] 123-Insulation Materials

[0227] 124-DC power supply

Claims

1. A ceramic bonded body comprising: a pair of ceramic plates comprising a conductive substance; and The conductive layer and the insulating layer are interposed between the pair of ceramic plates. The porosity at the interface between the pair of ceramic plates and the insulating layer is less than 4%. The ratio of the average primary particle size of the insulating material constituting the insulating layer to the average primary particle size of the insulating material constituting the ceramic plate is greater than 1.

2. The ceramic bonded body according to claim 1, wherein The conductive layer is composed of conductive material and insulating material. The insulating layer is made of an insulating material.

3. The ceramic bonded body according to claim 2, wherein: The insulating material constituting the insulating layer has an average primary particle size of 1.6 μm or more and 10.0 μm or less. The ceramic bonded body according to claim 1 , wherein: The ceramic plate is composed of a composite of aluminum oxide and silicon carbide. The ceramic bonded body according to claim 2 , wherein: The insulating material contained in the conductive layer and the insulating layer is composed only of aluminum oxide. The ceramic bonded body according to claim 2 , wherein: The conductive material contained in the conductive layer is at least one selected from the group consisting of Mo2C, Mo, WC, W, TaC, Ta, SiC, carbon black, carbon nanotubes, and carbon nanofibers.

7. An electrostatic chuck device comprising an electrostatic chuck member formed of ceramic and a temperature adjustment base member formed of metal bonded together via an adhesive layer, wherein: The electrostatic chuck component is composed of the ceramic bonded body according to any one of claims 1 to 6.

8. A method for producing a ceramic joint body, comprising: a step of grinding or polishing one surface of a first ceramic plate containing a conductive material to reduce the arithmetic mean roughness Ra of the one surface of the first ceramic plate to 0.25 μm or less; a step of applying a conductive layer forming paste to one surface of the first ceramic plate subjected to grinding or polishing to form a conductive layer coating film, and applying an insulating layer forming paste to form an insulating layer coating film; a step of grinding or polishing one surface of a second ceramic plate containing a conductive material to reduce the arithmetic mean roughness Ra of the one surface of the second ceramic plate to 0.25 μm or less; a step of laminating the second ceramic plate so that the surfaces of the conductive layer coating film and the insulating layer coating film opposite to the surfaces in contact with the first ceramic plate are in contact with one surface of the second ceramic plate subjected to grinding or polishing; and A step of pressing a laminate comprising the first ceramic plate, the conductive layer coating, the insulating layer coating, and the second ceramic plate in a thickness direction while heating the laminate, wherein: The ratio of the average primary particle size of the insulating material constituting the insulating layer to the average primary particle size of the insulating material constituting the first ceramic plate and the second ceramic plate is greater than 1.

9. The method for producing a ceramic joint body according to claim 8, wherein: After the step of forming the conductive layer coating film, the step of forming the insulating layer coating film is performed.

10. The ceramic bonded body according to claim 1, wherein The conductive layer is in direct contact with and sandwiched between the pair of ceramic plates, The insulating layer is in direct contact with and sandwiched between the pair of ceramic plates. The ceramic bonded body according to claim 1 , wherein: The insulating layer is arranged on the periphery of the conductive layer, The ceramic plate is composed of a composite of aluminum oxide and silicon carbide. The conductive layer is composed of aluminum oxide and molybdenum carbide. The insulating layer is made of aluminum oxide.

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