Electrode-embedding member, its manufacturing method, and substrate holding member

Abstract

To provide an electrode embedded member that can make the resistance of an electrode high and increase the degree of freedom of electrode design, as well as maintain the resistance of a connecting member low and improve the reliability of electrical connection through the connecting member, a manufacturing method of the same, and a substrate holding member.SOLUTION: An electrode embedded member 100 includes a flat base 110 made of sintered ceramics, an electrode 120 embedded in the base 110, and a connecting member 130 electrically connected to the electrode 120 and embedded in the base 110. The electrode 120 is composed of Mo carbide. The connecting member 130 includes W metal.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an electrode-embedded member, a manufacturing method thereof, and a substrate holding member. [Background technology]

[0002] 2. Description of the Related Art Hitherto, there have been proposed, as members for semiconductor manufacturing equipment, members with embedded electrodes, such as susceptors having electrodes embedded in a ceramic sintered body, electrostatic chucks, or ceramic heaters.

[0003] Patent Document 1 discloses a technology for the purpose of providing a ceramic heater that has small variation in the resistance value of the heater electrode layer within a substrate and can uniformly heat semiconductor wafers, in which a heater electrode layer 5 is formed on an aluminum nitride green sheet using a conductive paste containing tungsten carbide particles, and then a heat treatment process is carried out on the green sheet, in which the green sheet is heated in an inert gas atmosphere in a temperature range lower than the formation temperature of tungsten carbide, and then a firing process is carried out to completely sinter the green sheet, thereby completing the ceramic heater.

[0004] In Patent Document 1, a heater electrode layer is formed on a green sheet in advance using a conductive paste containing tungsten carbide (WC) particles, which has the smallest resistivity among tungsten carbides. It is described that if such a conductive paste is used in the heat treatment process, uneven carbonization reaction in the green sheet is less likely to occur compared to conventional conductive pastes that do not contain any carbon in the particles, and then the green sheet is heated in a non-oxidizing atmosphere at a temperature range lower than that during main firing, and organic substances contained in the sheet are decomposed and removed, resulting in a green sheet in a state suitable for main firing, and by main firing this, a sintered aluminum nitride body with small variation in the resistance value of the heater electrode layer within the substrate can be obtained. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2000-12194 A Summary of the Invention [Problem to be solved by the invention]

[0006] When a ceramic sintered body is produced by simultaneously embedding an Mo electrode and a W connection member in a ceramic molded body and firing the ceramic sintered body, the C component mixed in from the raw material, jig, and environment inevitably reacts with the Mo electrode and the W connection member. In this case, for example, if the carbonization of Mo is actively promoted to increase the resistance value of the electrode, the W connection member also carbonizes at the same time, and the connection member itself becomes highly resistant, deteriorating its function of electrically connecting the electrode and the (external) terminal. Furthermore, the carbonization makes the connection member itself embrittled, and when the terminal is subsequently brazed to the connection member, cracks are likely to occur and the terminal strength is reduced. Therefore, there has been a demand for an electrode embedding member and a manufacturing method thereof that simultaneously controls the carbonization of the Mo electrode and the W connection member when the Mo electrode and the W connection member are simultaneously embedded in a ceramic molded body and fired, thereby suppressing the above-mentioned functional deterioration.

[0007] However, although Patent Document 1 controls the carbonization of the electrode layer, it does not aim to actively carbonize the electrode layer, and is unable to control the carbonization of both the electrode layer and the connecting member.

[0008] The inventors noted that the temperature at which carbonization begins is different between Mo and W, and discovered that by performing heat treatment at a temperature above the carbonization temperature of Mo and below the carbonization temperature of W, it is possible to promote carbonization of the Mo electrode while suppressing carbonization of the W connecting member, thereby completing the present invention.

[0009] In other words, the present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide an electrode-embedded member, a manufacturing method thereof, and a substrate holding member that can increase the resistance of the electrode, increase the freedom of electrode design, while keeping the resistance of the connecting member low, and improve the reliability of the electrical connection via the connecting member. [Means for solving the problem]

[0010] (1) In order to achieve the above object, the present invention provides an electrode-embedded member, comprising a flat-plate-shaped base body made of a ceramic sintered body, an electrode embedded in the base body, and a connection member electrically connected to the electrode and embedded in the base body, the electrode being made of Mo carbide, and the connection member containing W metal. The connecting member has a W carbide layer having a thickness of more than 0 μm and not more than 20 μm on the surface. It is characterized by the following.

[0011] In this way, by constructing the electrodes from Mo carbide, the resistance of the electrodes can be increased, allowing for greater freedom in electrode design, and by using a connecting member that contains W metal, the resistance of the connecting member can be kept low, improving the reliability of the electrical connection via the connecting member.

[0012] (2) As mentioned above, In the electrode-embedded member of the present invention, the connection member has a W carbide layer having a thickness of more than 0 μm and not more than 20 μm on the surface.

[0013] In this way, by making the carbide layer on the surface of the connecting member very thin, it is possible to prevent the connecting member from becoming highly resistive, further improving the reliability of the electrical connection via the connecting member, and also to prevent the connecting member from becoming embrittled, thereby reducing the risk of cracks occurring in the connecting member.

[0014] (3) The electrode-embedded member of the present invention is characterized by further comprising a first member in contact with the connection member and made of Mo, Mo carbide, or a combination of Mo and Mo carbide.

[0015] This makes it possible to further suppress carbonization of the connection member, further improve the reliability of the electrical connection via the connection member, and further reduce the risk of cracks occurring in the connection member.

[0016] (4) In the electrode-embedded member of the present invention, the first member is a coating layer.

[0017] This makes it possible to further suppress carbonization of the connection member, further improve the reliability of the electrical connection via the connection member, and further reduce the risk of cracks occurring in the connection member.

[0018] (5) The substrate holding member of the present invention is characterized by comprising an electrode-embedding member according to any one of (1) to (4) above, and a terminal electrically connected to the connection member.

[0019] This makes it possible to construct a substrate holding member using an electrode-embedded member that allows for a high degree of freedom in electrode design and improves the reliability of the electrical connection via the connecting member, thereby reducing the risk of problems occurring in the connection between the terminal and the connecting member.

[0020] (6) Furthermore, the present invention provides a method for producing an electrode-embedded member formed of a sintered ceramic body, the method comprising the steps of: forming a plurality of ceramic bodies from a ceramic raw material powder; degreasing the plurality of ceramic bodies at a predetermined temperature or higher for a predetermined time or longer to produce a plurality of ceramic degreased bodies; preparing an electrode formed of a mesh woven with Mo wires and a connecting member formed of W; combining the electrode, the connecting member, and the plurality of ceramic degreased bodies to form an electrode-embedded member precursor formed in a flat plate shape and having the electrode and the connecting member embedded therein; a heat treatment step of heat treating the electrode-embedded member precursor at 800°C or higher and 1500°C or lower for 14 hours or longer; and a firing step of uniaxially pressurizing and firing the electrode-embedded member precursor after the heat treatment in a direction perpendicular to a main surface of the electrode-embedded member precursor to fire the electrode-embedded member.

[0021] This promotes carbonization of the electrodes in the heat treatment process, making it possible to configure the entire electrodes from Mo carbide, while preventing carbonization of the connection members. As a result, it is possible to increase the resistance of the electrodes, increase the degree of freedom in electrode design, and keep the resistance of the connection members low, improving the reliability of the electrical connection via the connection members.

[0022] (7) Furthermore, the method for producing an electrode-embedded member of the present invention is characterized in that in the preparation step, a first member made of Mo is further prepared, and in the precursor formation step, the first member is placed in contact with the connection member, and the first member is embedded in the electrode-embedded member.

[0023] This makes it possible to further suppress carbonization of the connecting member, to suppress an increase in the resistance of the connecting member, to further improve the reliability of the electrical connection via the connecting member, and to suppress embrittlement of the connecting member, thereby reducing the risk of cracks occurring in the connecting member.

[0024] (8) In the method for producing an electrode-embedded member of the present invention, the connection member prepared in the preparation step is coated with Mo.

[0025] This makes it possible to further suppress carbonization of the connecting member, to suppress an increase in the resistance of the connecting member, to further improve the reliability of the electrical connection via the connecting member, and to suppress embrittlement of the connecting member, thereby reducing the risk of cracks occurring in the connecting member. Effect of the Invention

[0026] According to the present invention, by forming the electrodes of the electrode-embedded member from Mo carbide, the resistance of the electrodes can be increased, and the degree of freedom in electrode design can be increased. Furthermore, by making the connecting member contain W metal, the resistance of the connecting member can be kept low, and the reliability of the electrical connection via the connecting member can be improved. [Brief description of the drawings]

[0027] [Figure 1] 1 is a cross-sectional view showing an example of an electrode-embedded member according to a first embodiment. [Diagram 2] 1 is a cross-sectional view showing an example of a substrate holding member according to a first embodiment. [Diagram 3] 4 is a flowchart showing a method for manufacturing an electrode-embedded member according to the first embodiment. [Figure 4] 1(a) to 1(d) are cross-sectional views each showing a schematic diagram of one stage in the manufacturing process of the electrode-embedded member according to the first embodiment. [Diagram 5] 1(a) to 1(c) are cross-sectional views each showing a schematic diagram of a stage in a manufacturing process of a substrate holding member according to a first embodiment. [Figure 6] 11 is a cross-sectional view showing an example of an electrode-embedded member according to a second embodiment. FIG. [Figure 7] FIG. 11 is a partial cross-sectional view showing a modified example of an electrode-embedded member according to the second embodiment. [Figure 8] 10 is a cross-sectional view showing an example of a substrate holding member according to a second embodiment. FIG. [Figure 9] 1 is a table showing the production conditions and measurement results of Examples and Comparative Examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Next, an embodiment of the present invention will be described with reference to the drawings. In order to facilitate understanding of the description, the same reference numerals are used for the same components in each drawing, and duplicated descriptions will be omitted. In the configuration diagrams, the size of each component is conceptually shown, and does not necessarily represent the actual dimensional ratio.

[0029] [First embodiment] [Configuration of electrode embedding material] First, the configuration of the electrode embedding member according to this embodiment will be described. Fig. 1 is a cross-sectional view showing an example of the electrode embedding member according to this embodiment. The electrode embedding member 100 according to this embodiment includes a base body 110, an electrode 120, and a connection member 130. The electrode embedding member 100 is applied to a heater, an electrostatic chuck, and the like.

[0030] The base 110 is made of a ceramic sintered body, formed in a flat plate shape, and has a mounting surface 112 on one of its main surfaces for mounting a substrate. Various materials can be used for the material of the base 110 depending on the application. For example, AlN, Al2O3, Si3N4, SiC, etc. can be used. The shape of the base 110 can be various shapes such as a disk shape, a polygonal shape, an ellipse shape, etc.

[0031] The ceramic sintered body forming the base 110 is preferably composed mainly of AlN. The term "composed mainly of AlN" means that the ceramic sintered body contains 90 wt% or more of AlN. In order to increase the thermal conductivity, sintering aids made of oxides of 2a group elements or 3a group elements are often added to AlN ceramics. In general, it is known that the thermal conductivity increases when the amount of sintering aid added is increased, but adding more than a certain amount causes a decrease in the thermal conductivity. Therefore, it is desirable to set the content of the sintering aid made of oxides of 2a group elements or 3a group elements to 10 wt% or less. Examples of additives of 2a group elements include Mg, Ca, Sr, Ba, etc., and examples of additives of 3a group elements include Y, La, Sm, Ce, etc.

[0032] A ceramic sintered body mainly composed of AlN has high thermal conductivity and excellent heat resistance and plasma resistance, and the thermal conductivity can be easily adjusted by adjusting the type and amount of sintering aid added. Therefore, by forming the base 110 from a ceramic sintered body mainly composed of AlN, the thermal conductivity can be adjusted and the base 110 with excellent heat resistance and plasma resistance can be configured.

[0033] The electrode 120 is embedded in the substrate 110 and is made of Mo carbide. By making the electrode 120 of Mo carbide in this way, the resistance of the electrode 120 can be increased, and the degree of freedom in electrode design can be increased. The electrode 120 being made of Mo carbide means that an element mapping analysis of the entire cross section of the electrode 120 is performed in an EPMA analysis, C and Mo are quantified in atom % terms by the ZAF method, and the C / (C+Mo) ratio is 0.20 or more.

[0034] The electrode 120 is preferably formed of a mesh in which wires are woven. The wires forming the mesh preferably have a wire diameter of 0.02 mm or more and 0.15 mm or less. Mo and Mo carbide have a high melting point and are difficult to process, so wires with a wire diameter of less than 0.02 mm are difficult to manufacture. If wires with a wire diameter of more than 0.15 mm are woven to form a mesh, there is a high risk of the wires cracking during sintering. The thickness of the mesh at the intersections of the wires is greater than 0.25 mm, and when the ceramics on the upper part of the electrode 120 are configured as a thin insulating layer, there is an increased risk of cracking the insulating layer. In this way, by forming the electrode 120 with sufficiently thin wires, the risk of the wires cracking during sintering can be further reduced, and even if the ceramics on the upper part of the electrode 120 are configured as a thin insulating layer, there is a further reduced risk of cracking the insulating layer.

[0035] The substrate 110 may include a plurality of electrodes. For example, by including a heater electrode and an electrostatic attraction electrode, the electrode-embedded member 100 can be used as a heater-equipped electrostatic chuck. In this case, at least one of the electrodes may be the electrode 120 of the present invention. Two or more electrodes may be the electrode 120 of the present invention.

[0036] The connection member 130 is embedded in the base 110 and electrically connected to the electrode 120. This allows electricity to be supplied to the electrode 120 via the connection member 130. The connection member 130 contains W metal. The connection member 130 containing W metal is confirmed when 0.9 or more of W is detected from a cross section of the connection member 130 in a quantitative analysis by the ZAF method of EPMA.

[0037] The thickness of the connection member 130 is preferably 0.2 mm or more and 5 mm or less. If it is less than 0.2 mm, there is an increased risk of breakage when forming the terminal hole 142 for connecting the terminal 140. If it is more than 5 mm, there is an increased risk of cracks occurring in the base 110 due to the difference in contraction rate between the base 110 and the ceramics of the base 110 during firing and the difference in thermal expansion rate during use.

[0038] It is preferable that the connection member 130 has a W carbide layer of more than 0 μm and not more than 20 μm on the surface. In this way, by making the carbide layer on the surface of the connection member 130 very thin, it is possible to suppress the connection member 130 from becoming highly resistive, and it is possible to further improve the reliability of the electrical connection via the connection member 130, and it is possible to suppress the connection member 130 from becoming brittle, thereby reducing the risk of cracks occurring in the connection member 130. Since the carbonization of W is unlikely to progress in the manufacturing method of the present invention, it is possible to make the W carbide layer on the surface of the connection member 130 thin.

[0039] In the electrode-embedded member of the present invention, by constructing the electrode from Mo carbide, the resistance of the electrode can be increased, thereby increasing the degree of freedom in electrode design, and by making the connecting member contain W metal, the resistance of the connecting member can be kept low, thereby improving the reliability of the electrical connection via the connecting member.

[0040] [Configuration of the substrate holding member] 2 is a cross-sectional view showing an example of the substrate holding member according to the first embodiment. The substrate holding member 200 according to this embodiment is provided with a terminal hole 142 in the electrode-embedded member 100 according to this embodiment, and is equipped with a terminal 140. The terminal 140 is electrically connected to the connection member 130. This allows power to be supplied to the electrode 120. The terminal 140 can be made of Ni or the like. The terminal 140 is brazed to the connection member 130 with Au solder or the like. An intermediate member 150 made of Kovar or the like may be provided between the connection member 130 and the terminal 140.

[0041] The substrate holding member of the present invention has a high degree of freedom in electrode design, and can be configured to use electrode-embedded members that improve the reliability of electrical connection via the connecting member, thereby reducing the risk of malfunctions in the connection between the terminal and the connecting member.

[0042] [Method of manufacturing electrode-embedded members] Next, a manufacturing method of an electrode-embedded member according to this embodiment will be described. Fig. 3 is a flow chart showing a manufacturing method of an electrode-embedded member according to a first embodiment of the present invention. As shown in Fig. 3, the manufacturing method of an electrode-embedded member according to the first embodiment of the present invention includes a green body forming step STEP 1, a degreasing step STEP 2, a preparation step STEP 3, a precursor forming step STEP 4, a heat treatment step STEP 5, and a firing step STEP 6. Note that, in the following, a manufacturing method using a green body hot pressing method in which green bodies are stacked to manufacture the member will be described, but in the present invention, the temperature and time of the heat treatment step STEP 5 are important, and the other steps may be replaced with other methods.

[0043] 4(a) to 4(d) are cross-sectional views each showing a schematic diagram of one stage in the manufacturing process of the electrode-embedded member according to the present embodiment. 4(a) to 4(d) show the case of manufacturing the electrode-embedded member of FIG.

[0044] In the molded body forming step STEP 1, a plurality of ceramic molded bodies 11, 12 are formed from ceramic raw material powder. In FIG. 4, the ceramic molded body is divided into two members, but may be three or more members depending on the design. For example, additives such as binder, plasticizer, dispersant, etc. are appropriately added to the ceramic raw material powder and mixed to prepare a slurry, and granules (ceramic raw material powder) are granulated by a spray drying method or the like, and then the slurry is pressure-molded to form a plurality of ceramic molded bodies 11, 12. When a manufacturing method using a binder is used in this way, the C component derived from the binder remains in the ceramic degreased body at about 100 ppm to 500 ppm even after the degreasing step described later. It is presumed that this C component causes carbonization. In the present invention, since it is necessary to sufficiently carbonize Mo of the electrode, it is preferable that the C component remains in the degreased body to this extent. A powder serving as a sintering aid may be added to the ceramic raw material powder as necessary.

[0045] The ceramic raw material powder is preferably of high purity, preferably 96% or more, more preferably 98% or more, and preferably has an average particle size of 0.1 μm or more and 1.0 μm or less.

[0046] 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 molded body is not limited to pressing, and may be, for example, green sheet lamination or casting, which may be appropriately degreased or further calcined to produce the ceramic molded body. The electrode-embedded member precursor may be formed by a powder hot pressing method.

[0047] After forming, the ceramic molded bodies 11 and 12 may be machined to adjust the shape of the molded bodies. As shown in Fig. 4(b), a recess may be formed on one side of the ceramic molded body 12 (the surface to be joined with another ceramic molded body 11) in a shape that matches the shape of the electrode 120 and the connection member 130. The recess may be provided on the ceramic molded body 11 or on both sides. The machining may be performed after degreasing.

[0048] In the degreasing step STEP 2, the ceramic molded bodies 11, 12 are degreased at a predetermined temperature or higher for a predetermined time or longer to produce a plurality of ceramic degreased bodies 21, 22. The ceramic molded bodies 11, 12 are heat treated at a temperature of, for example, 400°C to 800°C to become the ceramic degreased bodies 21, 22. The degreasing time is preferably 1 hour to 120 hours. For the degreasing, an atmospheric furnace or a nitrogen atmosphere furnace can be used, but an atmospheric furnace is preferable in order to remove unnecessary components of the binder.

[0049] In the preparation step STEP 3, an electrode 120 formed of a mesh woven with Mo wires and a connection member 130 formed of W are prepared.

[0050] The material of the electrode 120 is mainly composed of Mo. The term "mainly composed of Mo" means that the purity is 98 wt% or more, and the total of other transition metals, rare earth elements, or their compounds, and C is 2 wt% or less. The electrode 120 mainly composed of Mo undergoes a heat treatment step STEP 5 and a firing step STEP 6 described below, and becomes the electrode 120 composed of Mo carbide. The electrode 120 is prepared by processing into a shape according to the design of the electrode embedding member 100. The shape is preferably a mesh with wires woven in consideration of ease of carbonization. When the electrode 120 is in the shape of a mesh, the wire diameter of the wire forming the mesh is preferably 0.02 mm or more and 0.15 mm or less.

[0051] The material of the connection member 130 is mainly composed of W. The term "mainly composed of W" indicates that the purity is 97 wt% or more, and that the total of other transition metals and rare earth elements or their compounds and C is 3 wt% or less. The connection member 130 mainly composed of W is less likely to be carbonized even after undergoing the heat treatment step STEP 5 and the firing step STEP 6 described below, and therefore becomes the connection member 130 containing W metal. The connection member 130 is prepared by processing into a shape according to the design of the electrode embedding member 100, and is embedded in a position according to the design.

[0052] In the precursor formation step STEP 4, the prepared electrode 120, connection member 130, and multiple ceramic degreased bodies 21, 22 are combined to form an electrode-embedded member precursor 30 formed in a flat plate shape with the electrode 120 and connection member 130 embedded therein.

[0053] In the heat treatment step STEP 5, the electrode-embedding member precursor 30 is heat-treated at 800° C. to 1500° C. for 14 hours or more. As a result, the Mo in the electrode 120 is carbonized to become Mo carbide. On the other hand, since the heat treatment is performed at a temperature lower than the carbonization temperature of W, the W in the connection member 130 is not easily carbonized.

[0054] In the firing step STEP6, the heat-treated electrode-embedded member precursor 30 is uniaxially pressurized and fired in a direction perpendicular to the main surface (mounting surface) to obtain the electrode-embedded member 100. The pressure is preferably 1 MPa or more. The firing temperature is preferably higher than 1500°C and lower than 2000°C. The firing time is preferably 1 hour or more and 12 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, the multiple ceramic degreased bodies 21 after the heat treatment are sintered to become ceramic sintered bodies, which are integrated to obtain the electrode-embedded member 100 in which the electrodes 120 and the connecting members 130 are embedded. The firing may be performed by increasing the temperature continuously from the heat treatment.

[0055] In this way, it is possible to manufacture an electrode-embedded member that can increase the resistance of the electrode, thereby increasing the freedom of electrode design, while keeping the resistance of the connecting member low, thereby improving the reliability of the electrical connection via the connecting member.

[0056] In addition, a ceramic calcined body preparation step may be provided between the degreasing step STEP 2 and the precursor formation step STEP 4. When the ceramic calcined body preparation step is provided, the ceramic degreased body is calcined at a temperature of 1200°C to 1700°C to prepare a ceramic calcined body. This makes it possible to improve the dimensional accuracy of the outer shape of the electrode-embedded member and the embedding positions of the electrodes and connecting members. The calcination time is preferably 0.5 hours to 12 hours. The calcination atmosphere is preferably a nitrogen or inert gas atmosphere, but may be a vacuum atmosphere. When the calcined body preparation step is provided, mechanical processing may be performed after the calcined body preparation step.

[0057] [Method of manufacturing the substrate holding member] 5(a) to 5(c) are cross-sectional views each showing a schematic diagram of a step in the manufacturing process of the substrate holding member according to the present embodiment, in which the substrate holding member shown in FIG.

[0058] A terminal hole 142 is provided in the fired electrode-embedded member 100 to expose the surface of the connection member 130. At this time, if a W carbide layer (not shown) is formed on the surface of the connection member 130, the W carbide layer in the area of ​​the terminal hole is also removed. This allows the terminal 140 to be connected to the W metal of the connection member 130, whose resistance is kept low. The terminal 140 is connected to the exposed connection member 130 with a brazing material or the like. Ni or the like can be used for the terminal. Alternatively, Au brazing material or the like can be used for the brazing material. An intermediate member 150 made of Kovar or the like can be placed between the connection member 130 and the terminal 140 for brazing.

[0059] In this way, it is possible to construct a substrate holding member using an electrode-embedded member that has a high degree of freedom in electrode design and improves the reliability of the electrical connection via the connecting member, and it is possible to manufacture a substrate holding member 200 that can reduce the risk of malfunction in the connection between the terminal and the connecting member.

[0060] [Second embodiment] [Configuration of electrode embedding material] Next, the configuration of an electrode embedding member according to the second embodiment will be described. Fig. 6 is a cross-sectional view showing an example of an electrode embedding member according to this embodiment. The electrode embedding member 100 according to this embodiment includes a base 110, an electrode 120, a connection member 130, and a first member 160. The electrode embedding member 100 is applied to heaters, electrostatic chucks, and the like. Except for the inclusion of the first member 160, the basic configuration of the electrode embedding member 100 is the same as that of the first embodiment, and therefore only the different parts will be described.

[0061] The first member 160 is in contact with the connection member 130 and is made of Mo, Mo carbide, or a combination of Mo and Mo carbide. This makes it possible to further suppress carbonization of the connection member 130, further improve the reliability of the electrical connection via the connection member 130, and further reduce the risk of cracks occurring in the connection member 130.

[0062] When the first member 160 is provided as a plate-like member, the shape of the first member 160 is preferably the same as that of the connection member 130, and the thickness is preferably 0.2 mm to 5 mm. If the thickness is less than 0.2 mm, the forming process and the arrangement process become difficult. If the thickness is more than 5 mm, the risk of cracks occurring in the base 110 increases due to the difference in contraction rate between the base 110 and the ceramics of the base 110 during firing and the difference in thermal expansion rate during use. When the first member 160 is provided as a plate-like member, the first member 160 is preferably disposed on the side of the connection member 130 that is connected to the terminal 140.

[0063] Fig. 7 is a partial cross-sectional view showing a modified example of the electrode-embedded member according to the present embodiment. In the example of Fig. 6, the first member 160 is provided as a member separate from the connection member 130, but the first member 160 may be provided as a coating layer 162 that coats the connection member 130 as in the example of Fig. 7.

[0064] The thickness of the coating layer 162 is preferably 0.1 μm or more and 100 μm or less. A layer thinner than 0.1 μm is difficult to manufacture and consumes less C component, so that the carbonization suppression effect of the connection member 130 is reduced. When providing a layer thicker than 100 μm, it is easier to use a separate member instead of the coating layer 162.

[0065] When connection member 130 is formed as a plate-like member, coating layer 162 is preferably provided on both main surfaces of connection member 130 from the viewpoint of suppressing carbonization of connection member 130, but may be provided on only one surface. When provided on only one surface, coating layer 162 is preferably provided on the side of connection member 130 that is connected to terminal 140. Note that connection member 130 provided with coating layer 162 and plate-like first member 160 may be used in combination.

[0066] This allows the first member 160 to be provided in advance as a coating layer 162 on the connection member 130, facilitating production and consuming the C component in the vicinity of the connection member 130. As a result, carbonization of the connection member 130 can be further suppressed, the reliability of the electrical connection via the connection member 130 can be further improved, and the risk of cracks occurring in the connection member 130 can be further reduced.

[0067] [Configuration of the substrate holding member] FIG. 8 is a cross-sectional view showing an example of the substrate holding member according to the present embodiment. The substrate holding member 200 according to the present embodiment is provided with a terminal hole 142 in the electrode-embedded member 100 according to the present embodiment and is provided with a terminal 140. At this time, it is preferable to remove the first member 160 or the coating layer 162 in the range of the terminal hole 142. The first member 160 or the coating layer 162 other than the range of the terminal hole 142 may be left as it is. If a W carbide layer (not shown) is formed on the surface of the connection member 130 after removing the first member 160 or the coating layer 162, the W carbide layer in the range of the terminal hole is also removed. This allows the terminal 140 to be connected to the W metal of the connection member 130, whose resistance is kept low.

[0068] [Method of manufacturing electrode-embedded member and substrate-holding member] The method for manufacturing the electrode-embedded member and the substrate-holding member according to this embodiment is almost the same as the method for manufacturing the electrode-embedded member and the substrate-holding member according to the first embodiment, so only the different parts will be explained.

[0069] In the manufacturing method of the electrode-embedded member and the substrate holding member according to this embodiment, in addition to the electrode 120 and the connection member 130, a first member 160 made of Mo, or a connection member 130 made of W coated with Mo, is prepared in a preparation step.

[0070] Thereby, the C component in the vicinity of the connection member 130 is consumed by the first member 160 or the coating layer 162 during heat treatment and firing. As a result, carbonization of the connection member 130 can be further suppressed, the reliability of the electrical connection via the connection member 130 can be further improved, and the risk of cracks occurring in the connection member 130 can be further reduced. The coating layer 162 can be provided on the W connection member 130 by plating or spraying. When forming a recess in the ceramic molded body or the ceramic degreased body, it is preferable to form the recess in consideration of the thickness of the first member 160 or the coating layer 162.

[0071] [Examples and Comparative Examples] Example 1 Ceramic raw material powder, mainly composed of AlN with 5wt% Y2O3 added, was used for CIP molding (pressure 1ton / cm 2 ) to obtain an ingot of a molded body. This was machined to form a ceramic molded body with a diameter of 340 mm and a thickness of 5 mm, and a ceramic molded body with a diameter of 340 mm and a thickness of 30 mm. A recess with a diameter of 300 mm and a depth of 0.1 mm was provided on one side of the 30 mm thick ceramic molded body, sharing the center of the molded body, for accommodating an electrode. Furthermore, a recess with a diameter of 8.5 mm and a depth of 0.25 mm was provided at a predetermined position for forming a terminal, for accommodating a connecting member.

[0072] Next, the ceramic molded body was degreased at 550°C for 12 hours to prepare a ceramic degreased body. Next, a molybdenum mesh (wire diameter 0.1 mm, plain weave, mesh size #50) made of molybdenum with a diameter of 294 mm was cut into a predetermined shape to prepare an electrode. In addition, two connecting members with a size of φ8 mm x 0.2 mmt were prepared from W pellets. Next, the connecting members and electrodes were placed in the recesses of the ceramic degreased body with recesses, and sandwiched between the other ceramic degreased body to prepare an electrode-embedded member precursor.

[0073] Next, the electrode-embedded member precursor was placed in a hot press furnace and heat-treated for 14 hours from 800°C to 1500°C. Next, the electrode-embedded member precursor was uniaxially hot-pressed and fired at 1800°C for 2 hours while applying a force of 10 MPa in a direction perpendicular to the main surface (mounting surface) of the electrode-embedded member precursor. In this manner, the electrode-embedded member was fired.

[0074] Then, the entire surface was ground and polished to form a wafer mounting surface with a total thickness of 25 mm, an insulating layer thickness of 1.0 mm, and a surface roughness of Ra 0.4 μm. A flat-bottom hole with a hole diameter of φ5.5 mm was drilled from the back side of the ceramic base to the terminal position of the connecting member. A buffer member made of Kovar with a diameter of 5 mm and a thickness of 2 mm and a cylindrical Ni power supply terminal with a diameter of 5 mm and a length of 30 mm were installed on the exposed bottom surface of the connecting member via brazing material, and brazing was performed with Au-Ni-based brazing material at 1050 ° C. in a vacuum furnace to complete the substrate holding member. In this way, the substrate holding member of Example 1 was produced.

[0075] Example 2 In Example 2, a connecting member in which Mo was plasma sprayed onto the surface of W to form a coating having a thickness of 20 μm was used instead of the W connecting member used in Example 1. A substrate holding member for Example 2 was produced under the same conditions as in Example 1 except for the above.

[0076] Example 3 In Example 3, a Mo member (first member) was embedded in the W connection member of Example 1. The Mo member had a diameter of 8 mm and a thickness of 0.8 mm. After firing, the Mo member in the area of ​​the terminal hole was removed by processing. The substrate holder of Example 3 was produced under the same conditions as Example 1.

[0077] Example 4 In Example 4, a substrate holding member of Example 4 was produced under the same conditions as in Example 1, except that the heat treatment time was 20 hours.

[0078] Example 5 In Example 5, a substrate holding member of Example 5 was produced under the same conditions as in Example 1, except that the heat treatment time was 12 hours.

[0079] Comparative Example 1 In Comparative Example 1, no long-term heat treatment was performed. That is, the temperature was raised from 800°C to 1500°C for 7 hours, the same as in the conventional method, and then uniaxial pressure firing was performed for 2 hours at 1800°C. The substrate holder of Comparative Example 1 was produced under the same conditions as in Example 1.

[0080] Comparative Example 2 In Comparative Example 2, a Mo-coated connecting member similar to that in Example 2 was used. A substrate holding member for Comparative Example 2 was produced under the same conditions as in Comparative Example 1 except for the above.

[0081] Comparative Example 3 In Comparative Example 3, a Mo member (first member) was embedded in a W connection member in the same manner as in Example 3. The substrate holding member of Comparative Example 3 was produced under the same conditions as in Comparative Example 1 except for that.

[0082] [Performance evaluation] (Measurement of temperature distribution) After installing the fabricated substrate holding member (heater) in the evaluation chamber, the temperature was controlled at 400°C by self-heating, and the surface distribution was measured with an IR camera. The measurement area was within a Φ290mm range, and the temperature variation was evaluated as ΔT = maximum value - minimum value.

[0083] (Evaluation of resistance variation) After measuring the temperature distribution, terminal holes for resistance measurement were provided at predetermined positions to expose the heater electrodes. The tester probe was brought into contact with the heater electrodes exposed in the predetermined terminal holes, and the heater resistance between the predetermined terminals was measured at eight locations (four locations on the outer periphery at a radius of 135 mm, and four locations on the inner periphery at a radius of 50 mm). The ratio (Rm / Rd) of the design resistance value Rd to the measured resistance value Rm at the eight locations (maximum value - minimum value) / average value was evaluated as the resistance variation of the electrodes.

[0084] (Composition analysis of electrodes and connecting materials) The heater was cut in a vertical cross section passing through the center of the mounting surface and the center of the connecting member, and the cross sections of the electrodes and connecting members were exposed and polished, after which elemental analysis was performed using EMPA and qualitative analysis was performed using XRD. Elemental analysis of the electrodes was performed on three locations: the position closest to the center of the mounting surface, the position closest to the periphery, and the position closest to the midpoint of the two.

[0085] For the EPMA analysis of the electrode, elemental mapping analysis of the cross section of the electrode was performed using a FE-EPMA (field emission electron probe microanalyzer), and the presence of carbides was determined based on the C / (C+Mo) ratio in atom% conversion using the ZAF method. If the C / (C+Mo) ratio was 0.20 or higher, it was determined to be composed of Mo carbides, and if the C / (C+Mo) ratio was less than 0.20, it was determined that uncarburized Mo remained. For XRD, X-ray diffraction was performed on the cross section (a region with a diameter of approximately 3100 μm, including the diameter of the electrode) using μ-XRD (micro X-ray diffraction).

[0086] For the EPMA analysis of the connecting members, cross-sectional elemental mapping analysis of the ends of the cross-sections of the connecting members was performed using a FE-EPMA (field emission electron probe microanalyzer). The presence or absence of areas where C was detected was used to confirm the formation of carbides, and the thickness of the W carbide layer was measured based on the contrast difference between areas where carbides had formed and areas where they had not in the SEM images.

[0087] In Examples 1 to 5, the thickness of the carbonized layer on the surface of the W connection member could be reduced compared to Comparative Example 1. This is presumably because the time required to reach 800 to 1500°C was sufficiently longer than that of the conventional manufacturing method, and at least the C component near the connection member was consumed by the Mo electrode, Mo coating layer, and Mo first member, among the C components from the raw material, jig, and environment. At the same time, it was confirmed by both EPMA and XRD that the wire of the heater electrode was Mo carbide (Mo2C) at all of the above three points. The value of the C / (C+Mo) ratio in Figure 9 indicates the value at the point where the value was the smallest among the above three points. Therefore, it was found that a heat treatment time of 12 hours or more is sufficient to carbonize all the electrodes.

[0088] On the other hand, in Example 5, the thickness of the carbonized layer of the connection member was greater than that of Examples 1 and 4, which were identical in conditions except for the heat treatment time. Since it is preferable that the carbonized layer of the connection member is as thin as possible, it was found that the heat treatment time is preferably 14 hours or more, and more preferably 20 hours or more. The reason why the thickness of the carbonized layer becomes thinner as the heat treatment time is longer is presumed to be because the C component is not only consumed by Mo during the heat treatment, but is also discharged as gas such as CO.

[0089] In contrast, the carbonized layer on the surface of the W connecting member was thicker in Comparative Examples 1 to 3. At the same time, there were some parts of the wire cross section of the heater electrode that had a composite structure of Mo and Mo2C. Comparative Examples 2 and 3, which used Mo-coated connecting members or Mo pellets (first members), had thinner carbonized layers on the connecting members than Comparative Example 1, but the electrodes could not be carbonized entirely, so the variation in electrode resistance was large, just like Comparative Example 1, and the temperature distribution on the heater surface was also large.

[0090] As a result, it was confirmed that, compared to the comparative example, in Examples 1 to 5, the mixture of Mo and Mo2C was eliminated, the variation in heater resistance was improved, and the heater surface temperature distribution was improved. In addition, it was confirmed that the carbonization and embrittlement of the W connection member were suppressed, so that the reliability of brazing the terminal to the connection member could be improved. Furthermore, it was confirmed that the manufacturing method of the present invention can manufacture such electrode-embedded members and substrate holding members.

[0091] The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications and equivalents are included within the spirit and scope of the present invention. In addition, the structure, shape, number, position, size, etc. of the components shown in each drawing are for convenience of explanation and may be changed as appropriate. [Explanation of symbols]

[0092] 11, 12 Ceramic molding 21, 22 Ceramic degreased body 30 Electrode embedding material precursor 100 Electrode embedding member 110 Base 112 Placement surface 120 electrodes 130 Connection member 140 Terminals 142 Terminal hole 150 Intermediate parts 160 First Component 162 Coating Layer 200 Substrate holding member

Claims

1. An electrode embedding member, A flat plate-shaped base body made of a ceramic sintered body; An electrode embedded in the substrate; a connection member electrically connected to the electrode and embedded in the base, The electrode is made of Mo carbide, The connection member includes a W metal, and has a W carbide layer having a thickness of more than 0 μm and not more than 20 μm on a surface of the connection member.

2. 2. The electrode-embedded member according to claim 1, further comprising a first member in contact with the connection member and made of any one of Mo, Mo carbide, or a combination of Mo and Mo carbide.

3. 3. The electrode-embedded member according to claim 2, wherein the first member is a coating layer.

4. An electrode-embedded member according to any one of claims 1 to 3, a terminal electrically connected to the connection member.

5. A method for manufacturing an electrode-embedded member made of a ceramic sintered body, comprising the steps of: a compact forming step of forming a plurality of ceramic compacts from the ceramic raw material powder; a degreasing step of degreasing the plurality of ceramic molded bodies at a predetermined temperature or higher for a predetermined time or longer to produce a plurality of ceramic degreased bodies; A preparation step of preparing an electrode formed of a mesh woven with Mo wires and a connection member formed of W; a precursor forming step of combining the electrodes, the connection members, and the plurality of ceramic degreased bodies to form a plate-shaped electrode-embedded member precursor in which the electrodes and the connection members are embedded; a heat treatment step of heating the electrode-embedded member precursor from 800° C. to 1500° C. over 14 hours or more; a firing step of uniaxially pressurizing and firing the heat-treated electrode-embedded member precursor in a direction perpendicular to a main surface of the electrode-embedded member precursor to obtain an electrode-embedded member.

6. In the preparation step, a first member made of Mo is further prepared; 6. The method for producing an electrode-embedded member according to claim 5, wherein in the precursor formation step, the first member is disposed in contact with the connection member, and the first member is embedded in the electrode-embedded member.

7. 7. The method for manufacturing an electrode-embedded member according to claim 5, wherein the connection member prepared in the preparation step is coated with Mo.

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