Method for manufacturing ceramic sintered body, method for manufacturing electrode-embedded member, and electrode-embedded member

Abstract

To provide a method for manufacturing a ceramic sintered body including a via which can cope with larger current, a method for manufacturing an electrode embedding member, and the electrode embedding member.SOLUTION: A method for manufacturing a ceramic sintered body 100 including a via 130 includes the steps of: preparing a porous body 110 formed from a material containing tungsten and molybdenum or at least one of these and turning into the via due to sintering; preparing a flat-plate-like ceramic compact 120 and providing a hole 125 in which the porous body 110 is arranged in the ceramic compact 120; arranging the porous body 110 in the hole 125; and burning the ceramic compact 120 in which the porous body 110 is arranged. The porous body 110 is burnt simultaneously with the ceramic compact 120, and turns into the via 130 embedded into the ceramic sintered body.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a ceramic sintered body having a via, a method for manufacturing a buried electrode member, and a buried electrode member. [Background technology]

[0002] When manufacturing an electrode-embedded member as a semiconductor manufacturing device member, vias (electrical connection members) are formed to connect the internal electrodes embedded in the ceramic to terminals or to each other.

[0003] Patent Document 1 discloses a method for manufacturing an electrode-embedded member, which includes a preparation step of preparing a metal molded body to serve as a connecting member by pressure-molding a powder raw material containing a plurality of metal particles in order to suppress defects such as cracks in the base material of the electrode-embedded member, a ceramic body production step of producing a ceramic body in which an internal electrode and a metal molded body are embedded, and a substrate production step of firing the ceramic body in which the internal electrode and the metal molded body are embedded to produce a substrate in which a connecting member is embedded, the connecting member having a space inside which no metal is present.

[0004] Patent Document 2 discloses a wafer support member in which one main surface of a plate-like ceramic body is used as a mounting surface for mounting a wafer, at least one internal electrode is provided in the plate-like ceramic body, and a power supply terminal electrically connected to the internal electrode is provided on a surface of the plate-like ceramic body other than the mounting surface, in order to prevent an increase in current density on the surface of the electrostatic attraction electrode around a connection portion where the power supply terminal and the electrostatic attraction electrode are electrically connected, thereby causing an increase in temperature difference within the surface of the wafer and resulting in poor heating uniformity, the wafer support member having a power supply terminal electrically connected to the internal electrode, the thickness of the internal electrode around the connection portion where the power supply terminal and the internal electrode are electrically connected being made thicker than the thickness of the other internal electrodes.

[0005] Patent Document 3 discloses a ceramic joining structure in which a part of a metal member is exposed on the joining surface that comes into contact with the joining layer of a ceramic member to form an exposed metal portion, so as to prevent erosion of the embedded member or poor insulation even when exposed to air, etc., during long-term operation in a high-temperature range, and the ceramic member and the exposed metal portion are each joined to a metal joining member via a joining layer along this joining surface, and the main component of the joining layer is one or more metals selected from the group consisting of gold, platinum and palladium. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2019-208006 A [Patent Document 2] JP 2005-277335 A [Patent Document 3] Japanese Patent Application Publication No. 11-12053 Summary of the Invention [Problem to be solved by the invention]

[0007] In order to accommodate the increasing current of heaters and electrostatic chucks required in recent semiconductor manufacturing processes, it is necessary to suppress localized heat generation in vias. To achieve this, it is preferable for the vias to be large in diameter and as dense as possible, but Patent Document 1 does not take into consideration the densification of connection members, and Patent Document 3 does not take into consideration the increase in the diameter of terminals.

[0008] In the case of the green sheet lamination method as in Patent Document 2, via holes are formed by filling holes made in a sheet by screen printing with tungsten or molybdenum in a paste form. However, since the paste contains a large amount of organic binder and solvent components for making the paste, shrinkage occurs on the surface as shown in FIG. 1 during the drying process before firing, and the paste surface becomes concave relative to the ceramic surface, which causes a problem of poor electrical continuity when the sheets are laminated. This problem is particularly likely to occur when the ceramic green sheet is thick or the via diameter is large. In addition, when a ceramic molded body made by pressing ceramic powder is used, it is even more difficult to form vias by injecting paste into holes provided in the ceramic molded body.

[0009] Also, instead of using paste, vias have been made by making metal pellets of tungsten (W) or molybdenum (Mo), embedding these in a ceramic compact at the same time as electrodes, and firing them at the same time to create vias. However, when large pellets are embedded in a ceramic compact and fired at the same time, stress is generated due to the difference in the firing shrinkage rate between the ceramic and W or Mo, and cracks often occur near the boundary between the two after firing. For this reason, the dimensions of the W or Mo pellets could not be made large. As a result, there were limitations to the applicability of using the pellets themselves as vias and passing large currents through them.

[0010] The present invention has been made in consideration of the above circumstances, and aims to provide a method for manufacturing a ceramic sintered body having vias that can handle large currents, a method for manufacturing an electrode-embedded member, and an electrode-embedded member. [Means for solving the problem]

[0011] (1) In order to achieve the above object, the method for producing a ceramic sintered body of the present invention is a method for producing a ceramic sintered body having a via, and includes the steps of: preparing a porous body formed of tungsten, molybdenum, or a material containing at least one of them, which becomes the via by sintering; preparing a flat ceramic molded body, providing a hole in the ceramic molded body in which the porous body is to be placed; placing the porous body in the hole; and firing the ceramic molded body in which the porous body is placed, wherein the porous body is fired simultaneously with the ceramic molded body to become the via embedded in the ceramic sintered body.

[0012] In this way, by using a porous metal body and firing it simultaneously with a ceramic molded body, even if the shrinkage rate of the ceramic and the shrinkage rate of the porous body are different, it is possible to form a metallic via inside the ceramic sintered body. This makes it possible to reduce the occurrence of cracks in the ceramic sintered body due to the difference in shrinkage rate caused by the size of the dense metal body being too large when a via is formed using a dense metal body, and the contact failure of the via caused by the size of the dense metal body being too small.

[0013] (2) Furthermore, in the method for producing a ceramic sintered body of the present invention, the porous body is arranged in the hole portion without any gaps, and the step of sintering the ceramic molding is characterized in that the porous body is sintered by uniaxial hot press sintering in which pressure is applied in the height direction of the porous body.

[0014] As a result, since uniaxial hot press sintering shrinks only in the pressure direction, the shape and size of the holes can be made almost the same as the bottom surface of the porous body, and the size of the porous body only needs to be considered in terms of shrinkage in the height direction, making dimensional design easier. In addition, the occurrence of cracks in the ceramic sintered body and poor contact of vias can be more reliably reduced.

[0015] (3) Furthermore, in the method for producing a ceramic sintered body of the present invention, the porous body is formed into a cylindrical shape having a maximum diameter of 1.0 mm or more and a height of 1.0 mm or more after the step of sintering the ceramic molding.

[0016] This allows larger currents to be passed through larger via geometries.

[0017] (4) Furthermore, the manufacturing method of the electrode-embedded member of the present invention is a manufacturing method of an electrode-embedded member having a via, comprising the steps of: preparing a porous body formed of tungsten, molybdenum, or a material containing at least one of them, and which becomes the via by firing; preparing a flat first ceramic molding and providing a hole in the first ceramic molding in which the porous body is to be placed; placing the porous body in the hole; preparing an internal electrode and placing the internal electrode on the upper surface of the ceramic molding so as to overlap the hole; placing a second ceramic molding on the upper surface of the first ceramic molding on which the internal electrode and the porous body are placed; and firing the first and second ceramic moldings, wherein the porous body is fired simultaneously with the first and second ceramic moldings, and becomes the via that is embedded in a ceramic sintered compact and electrically connected to the internal electrode.

[0018] This makes it possible to form an electrode-embedded member that is less susceptible to cracks in the ceramic sintered body and to poor contact between the vias and the internal electrodes.

[0019] (5) Furthermore, the manufacturing method of the electrode-embedded member of the present invention further includes the steps of preparing a second internal electrode and arranging the second internal electrode on the underside of the first ceramic molding so as to overlap the hole portion, and arranging a third ceramic molding on the underside of the first ceramic molding on which the second internal electrode and the porous body are arranged, wherein the hole portion penetrates the first ceramic molding, and the porous body is fired simultaneously with the first, second, and third ceramic moldings and embedded in the ceramic sintered body to become the via that electrically connects the internal electrode and the second internal electrode.

[0020] This ensures electrical conductivity between the internal electrodes formed in different layers, and as a result, it is possible to minimize the number of holes formed from the outside of the electrode-embedded member and pass electricity through the internal electrodes, and by using one of the electrodes as a conductive wiring electrode, for example, it is possible to easily supply electricity to the heating resistor disposed in the outer peripheral region, making it easy to configure a multi-zone heater, etc.

[0021] (6) Also, this Reference embodiment of the disclosure The electrode-embedded member comprises a base formed of a sintered ceramic body, a plurality of internal electrodes embedded in a plurality of layers inside the base, and vias embedded inside the base and electrically connecting at least two of the plurality of internal electrodes, the vias being formed from tungsten, molybdenum, or a material containing at least one of them, and being formed in a columnar shape with a maximum diameter of 1.0 mm or more and a height of 1.0 mm or more.

[0022] This ensures electrical conductivity between the internal electrodes formed in different layers, and as a result, current can be passed through the internal electrodes while minimizing the number of holes formed from the outside of the electrode-embedded member, making it possible to configure, for example, a multi-zone heater. Effect of the Invention

[0023] According to the present invention, a method for manufacturing a ceramic sintered body having a via, a method for manufacturing a member with an embedded electrode, and a member with an embedded electrode can be provided, which can accommodate large currents. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a cross-sectional view showing a defect of the prior art. [Diagram 2] 3A to 3C are cross-sectional views showing an example of a manufacturing process for the ceramic sintered body having a via according to the first embodiment. [Diagram 3] 3A to 3C are cross-sectional views showing an example of a manufacturing process for the ceramic sintered body having a via according to the first embodiment. [Figure 4] 1A and 1B are top and bottom perspective views showing an example of a heater according to a second and third embodiment, respectively. [Diagram 5] 1A and 1B are top and bottom perspective views showing an example of an electrostatic chuck according to a second and third embodiment, respectively. [Figure 6] 5A to 5C are cross-sectional views showing an example of a manufacturing process for the heater according to the second embodiment. [Figure 7] FIG. 6 is a cross-sectional view showing an example of a heater according to a second embodiment. [Figure 8] 10A to 10C are cross-sectional views showing a modified example of the manufacturing process of the heater of the second embodiment. [Figure 9] FIG. 11 is a cross-sectional view showing a modified example of the heater of the second embodiment. [Figure 10] 10A to 10C are cross-sectional views showing an example of a manufacturing process for the heater according to the third embodiment. [Figure 11] FIG. 11 is a cross-sectional view showing an example of a heater according to a third embodiment. [Figure 12] FIG. 11 is a cross-sectional view showing a modified example of the heater of the third embodiment. [Figure 13] FIG. 11 is a cross-sectional view showing an example of an electrode-embedded member according to a third embodiment. [Figure 14] FIG. 11 is a cross-sectional view showing a modified example of an electrode-embedded member according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] 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.

[0026] [First embodiment] [Method of manufacturing sintered ceramics] A method for manufacturing a ceramic sintered body according to this embodiment will be described. Figures 2 and 3 are cross-sectional views showing an example of a manufacturing process of a ceramic sintered body 100 having a via according to the first embodiment. Figure 2 shows a manufacturing method by uniaxial hot pressing. Figure 3 shows a first embodiment manufacturing method by normal pressure firing.

[0027] First, a porous body 110 is prepared, which is formed of tungsten (W), molybdenum (Mo), or a material containing at least one of them, and which becomes a via by sintering. The relative density of the porous body 110 is preferably 40% or more and 90% or less, and more preferably 60% or more and 80% or less. A porous body having a relative density of less than 40% is difficult to manufacture, and is likely to have a larger shrinkage rate than the shrinkage rate when the ceramic molded body 120 is fired, making it difficult to adjust the size of the porous body 110 and the hole portion 125 described later. A porous body having a relative density of more than 90% is likely to have a significantly smaller shrinkage rate than the shrinkage rate when the ceramic molded body 120 is fired, making it difficult to adjust the size of the porous body 110 and the hole portion 125 described later. The difference between the maximum shrinkage rate of the porous body 110 during firing and the shrinkage rate of the ceramic molded body 120 during firing is preferably 0 to 50 points, more preferably 10 to 30 points.

[0028] The relative density and size of the porous body 110 are preferably determined according to the shrinkage rate when the ceramic molded body 120 is fired and the target relative density of the via 130 after sintering the porous body 110. The porous body 110 is preferably formed to have a cylindrical shape with a maximum diameter of 1.0 mm or more and a height of 1.0 mm or more after the step of firing the ceramic molded body 120. If the maximum diameter is less than 1.0 mm, it becomes difficult to manufacture the porous body 110. The maximum diameter of the porous body 110 after firing is more preferably 1.5 mm or more, and the height is more preferably 3.0 mm or more. This allows a larger current to pass through the large-shaped via 130 between different layers that are separated in the thickness direction of the ceramic sintered body 100 having the via. It is not necessary to set an upper limit for the maximum diameter and height of the porous body 110 after firing, but considering the size used as a via, the maximum diameter can be set to 10 mm or less and the height to 20 mm or less, for example. Furthermore, the porous body 110 may have a columnar shape other than a cylindrical shape.

[0029] Any method may be used for producing the porous body 110. For example, the porous body 110 can be produced by uniaxial press molding of a powder raw material in which a binder is added to metal particles. In order to remove the binder, a degreasing step may be performed in which the pressure-molded porous body 110 is degreased in an air atmosphere or a nitrogen atmosphere at a temperature range of 200°C to 600°C. In addition, the pressure-molded or degreased porous body 110 may be pre-fired in a nitrogen, argon, or vacuum atmosphere furnace at a temperature condition of, for example, 1000°C to 1800°C, to form the porous body 110 as a pre-fired body. In addition, the outer diameter and thickness of the porous body 110 may be adjusted by grinding or polishing.

[0030] Next, a flat ceramic molded body 120 is prepared. The ceramic molded body 120 can be produced by an existing method. The material can also be appropriately selected depending on the purpose of the ceramic sintered body 140 to be produced. For example, raw material powder such as Al2O3, AlN, Si3N4, SiC, etc. is granulated to produce granulated powder. Sintering aids, binders, etc. may be added. Then, the ceramic molded body 120 having a predetermined shape is produced using the obtained granulated powder. A degreasing process may be provided in which the ceramic molded body 120 is degreased at a predetermined temperature or higher for a predetermined time or longer. For degreasing, an atmospheric furnace or a nitrogen atmosphere furnace may be used.

[0031] Next, a hole 125 in which the porous body 110 is to be placed is provided in the ceramic molded body 120. The hole 125 is preferably made to a size that allows the porous body 110 after firing, i.e., the via 130, to be in close contact with the hole 125 after firing and reduces the stress therebetween, depending on the shrinkage rate of the ceramic molded body 120, the shrinkage rate of the porous body 110, the firing method, the firing conditions, and the like.

[0032] Next, the porous body 110 is placed in the hole 125. Then, the ceramic molded body 120 in which the porous body 110 is placed is fired. The sintering conditions may be the conditions for producing a normal ceramic sintered body, and for example, firing can be performed by holding at a temperature of 1400°C or higher and 2200°C or lower for 0.1 hours or higher and 10 hours or lower. Normal pressure firing or uniaxial hot press firing can be applied for firing. The relative density of the porous body 110 after sintering, i.e., the vias 130, is preferably higher than the relative density of the porous body 110. In addition, the relative density of the vias 130 is preferably higher than 80%, more preferably 90% or higher, and even more preferably 95% or higher.

[0033] In the case of uniaxial hot press sintering, it is preferable that the porous body 110 is arranged without gaps in the hole 125. That is, when the shrinkage rate of the porous body 110 is smaller than that of the ceramic molded body 120 and sintering is performed by uniaxial hot press sintering, the size of the surface perpendicular to the axial direction (pressure direction) of the hole 125 is approximately the same as the size of the surface perpendicular to the axial direction of the porous body 110, and the axial size of the hole 125 is preferably made larger than the axial size of the porous body 110, as shown in FIG.

[0034] Since uniaxial hot press sintering shrinks only in the pressure direction, the shape and size of the surface perpendicular to the axial direction of the hole 125 can be made substantially the same as the bottom surface of the porous body 110, and the size of the porous body 110 can be easily designed because only the shrinkage in the axial direction needs to be considered. Also, the occurrence of cracks in the ceramic sintered body 100 having vias and poor contact of the vias can be more reliably reduced.

[0035] On the other hand, in the case of normal pressure firing, it is preferable to arrange the porous body 110 and the hole 125 with an overall gap therebetween. That is, when the shrinkage rate of the porous body 110 is smaller than that of the ceramic molded body 120 and the porous body 110 is fired by normal pressure firing, it is preferable to make the overall size of the hole 125 larger than that of the porous body 110, as shown in Fig. 3. This is because, in the case of normal pressure firing, both the porous body 110 and the ceramic molded body 120 shrink overall.

[0036] Therefore, it is preferable to sinter the porous body 110 and the hole 125 by uniaxial hot press sintering, which allows easy size adjustment of the porous body 110 and the hole 125. In FIG. 2 and FIG. 3, the via 130 penetrates the ceramic sintered body 140, and the upper and lower surfaces of the via 130 are formed in a shape exposed to the upper and lower surfaces of the ceramic sintered body 100 having the via, but one or both surfaces of the via 130 may be formed in a shape covered by the ceramic sintered body 140. In that case, it is preferable that the covered surface is electrically connected to a conductive member (not shown) embedded in the ceramic sintered body 100 having the via, or a terminal hole is formed in which a part of the via 130 is exposed, and electrically connected from the outside. In addition, although terminals are not shown in FIG. 2 and FIG. 3, the number of terminals connected to the ceramic sintered body 100 having the via, i.e., the terminal connection positions, may be two or more than three.

[0037] The porous body 110 is fired simultaneously with the ceramic molded body 120 to form the vias 130 embedded in the ceramic sintered body 140 .

[0038] In this way, a ceramic sintered body 100 having a via can be manufactured. In the method for manufacturing a ceramic sintered body of the present invention, a metal porous body is used and fired simultaneously with a ceramic molded body, so that even if the shrinkage rate of the ceramic and the shrinkage rate of the porous body are different, a metal via can be formed inside the ceramic sintered body. This can reduce the occurrence of cracks in the ceramic sintered body due to the difference in shrinkage rate caused by the size of the metal dense body being too large when a via is formed using a metal dense body, and the contact failure of the via caused by the size of the metal dense body being too small.

[0039] [Second embodiment] [Method of manufacturing electrode-embedded members] A method for manufacturing an electrode-embedded member according to this embodiment will be described. The basic manufacturing method is the same as the method for manufacturing the ceramic sintered body 100 having a via of the first embodiment. The manufacturing method for the electrode-embedded member of this embodiment and the third embodiment will be described using the manufacturing method for the heater with a shaft shown in FIG. 4 as an example, but the manufacturing method for the electrode-embedded member of the present invention can be applied to the manufacturing of an electrostatic chuck shown in FIG. 5 and various electrode-embedded members having vias used for other purposes, and it goes without saying that the shape is not limited to the one shown. FIGS. 4(a) and (b) are upper and lower perspective views showing an example of a heater of the second and third embodiments, respectively. Also, FIGS. 5(a) and (b) are upper and lower perspective views showing an example of an electrostatic chuck of the second and third embodiments, respectively.

[0040] Fig. 6 is a cross-sectional view showing an example of a manufacturing process of the heater of this embodiment. Fig. 7 is a cross-sectional view showing an example of the heater of this embodiment. First, a porous body 110 is prepared, which is made of tungsten (W), molybdenum (Mo) or a material containing at least one of them and becomes a via 130 by sintering. The relative density of the porous body 110, the range of sizes after sintering, the manufacturing method, etc. are the same as those of the first embodiment.

[0041] Next, a flat-plate-shaped first ceramic molded body 121 is prepared. Next, a hole 125 in which the porous body 110 is disposed is provided in the first ceramic molded body 121. In this case, in the first embodiment, the hole 125 is described as penetrating the ceramic molded body 120, but in this embodiment, it is sufficient to bring the porous body 110 disposed in the hole 125 into contact with the internal electrode 150 disposed on the upper surface of the first ceramic molded body 121, so the hole 125 may be provided so as to penetrate the first ceramic molded body 121, or may not be provided so as to penetrate the first ceramic molded body 121. FIG. 6 shows an example in which the hole 125 does not penetrate. When the hole 125 is provided so as not to penetrate, a terminal hole 127 that reaches the via 130 from the lower surface after firing may be provided. It is preferable that the hole 125 is made to a size that allows the porous body 110 after firing, i.e., the via 130, to adhere closely to the hole 125 after firing according to the shrinkage rate of the first ceramic molded body 121 and the shrinkage rate of the porous body 110, and reduces the mutual stress. Next, the porous body 110 is placed in the hole 125.

[0042] Next, the internal electrode 150 is prepared and placed on the upper surface of the first ceramic molded body 121 so as to overlap the hole 125. The shape of the internal electrode 150 can be various shapes such as mesh and foil depending on the application. In addition, the material can be various materials such as molybdenum and tungsten depending on the application. The prepared internal electrode 150 is placed so as to overlap the hole 125 so as to be in reliable contact with the porous body 110 placed in the hole 125 after firing. At this time, a groove or the like matching the shape of the internal electrode 150 may be formed on the upper surface of the first ceramic molded body 121.

[0043] Next, the second ceramic molded body 122 is prepared and placed on the upper surface of the first ceramic molded body 121 on which the internal electrode 150 and the porous body 110 are placed. The second ceramic molded body 122 serves as a protective layer that covers the internal electrode 150 and the via 130. The second ceramic molded body 122 is preferably in the form of a flat plate.

[0044] The method for producing the first and second ceramic molded bodies 121, 122 may be an existing method as described above. Also, various materials may be used depending on the application. The second ceramic molded body 122 may be formed as a molded body and then placed on the upper surface of the first ceramic molded body 121, or the second ceramic molded body 122 may be obtained by filling the upper surface of the first ceramic molded body 121 with an appropriate amount of granulated ceramic powder and subjecting it to a pressure treatment.

[0045] The first and second ceramic molded bodies 121, 122 are fired to form an integrated ceramic sintered body 140 in which the internal electrode 150 and the via 130 are embedded. The porous body 110 is fired simultaneously with the first and second ceramic molded bodies 121, 122 to form the via 130 embedded in the ceramic sintered body 140 and electrically connected to the internal electrode 150. The via 130 is then electrically connected to the terminal 180. The number of terminals 180, i.e., the number of terminal connection positions of the electrode-embedding member 200, may be three or more.

[0046] When the electrode-embedded member 200 is used as a heater, it may be joined to the shaft 170 after firing. This makes it possible to make a heater with a shaft. The shaft 170 is preferably formed in a columnar shape such as a cylinder. In addition, the shaft 170 is preferably formed of a ceramic sintered body made of the same main component as the main component of the ceramic sintered body 140 of the electrode-embedded member 200.

[0047] (Modification) FIG. 8 is a cross-sectional view showing a modified example of the manufacturing process of the heater of the second embodiment using the third ceramic molded body and the connecting member (pellet). FIG. 9 is a cross-sectional view showing a modified example of the heater of the second embodiment using the third ceramic molded body and the pellet. In the step of providing the hole 125, the hole 125 may be provided so as to penetrate the first ceramic molded body 121, and the third ceramic molded body 123 in which the pellet 160 is provided at the position of the hole 125 of the first ceramic molded body 121 may be provided on the lower surface of the first ceramic molded body 121. The metal pellet 160 may be provided on the bottom surface of the hole 125 separately from the porous body 110.

[0048] In these cases, electrical connection from the outside can be made through the pellet 160, not directly to the via 130. The pellet 160 may be inserted between the internal electrode 150 and the porous body 110. In that case, a groove for accommodating the pellet 160 may be formed on the upper surface of the first ceramic molded body 121. The pellet 160 preferably has a maximum diameter of 5 mm to 12 mm and a thickness of 0.1 mm to 0.5 mm. The pellet 160 may be made of tungsten, molybdenum, or the like. The pellet 160 is a dense bulk body, not porous. The pellet 160 is sufficiently thin, so that it does not cause cracks in the ceramic sintered body 140 during firing and when the electrode-embedded member 200 is used.

[0049] In this manner, an electrode-embedded member 200 having an internal electrode 150 and a via 130 can be manufactured. The manufacturing method of the electrode-embedded member of the present invention can form an electrode-embedded member that is less susceptible to cracking of the ceramic sintered body and poor contact between the via and the internal electrode. Furthermore, the manufacturing method of the electrode-embedded member of the present invention can manufacture an electrode-embedded member in which even a large-diameter via is completely embedded in the ceramic sintered body, and can handle large currents.

[0050] [Third embodiment] [Method of manufacturing electrode-embedded members] A method for manufacturing an electrode-embedded member according to this embodiment will be described. The basic manufacturing method is the same as that for manufacturing the electrode-embedded member 200 of the second embodiment. FIG. 10 is a cross-sectional view showing an example of a manufacturing process for a heater according to this embodiment. FIG. 11 is a cross-sectional view showing an example of a heater according to this embodiment. First, a porous body 110 is prepared, which is made of tungsten (W), molybdenum (Mo), or a material containing at least one of these, and which becomes a via 130 by sintering. The relative density of the porous body 110, the range of sizes after sintering, the manufacturing method, etc. are the same as those of the first embodiment.

[0051] Next, a flat-plate-shaped first ceramic molded body 121 is prepared. Next, a hole 125 in which the porous body 110 is disposed is provided in the first ceramic molded body 121. At this time, in the second embodiment, the hole 125 does not need to penetrate the first ceramic molded body 121, but in this embodiment, the hole 125 is provided to penetrate the first ceramic molded body 121 so that the porous body 110 disposed in the hole 125 contacts the second internal electrode 152 disposed on the lower surface of the first ceramic molded body 121 after firing. Next, the porous body 110 is disposed in the hole 125.

[0052] Next, the internal electrode 150 is prepared and placed on the upper surface of the first ceramic molded body 121 so as to overlap the hole portion 125. The shape and material of the internal electrode 150 are the same as those in the second embodiment. The prepared internal electrode 150 is placed so as to overlap the hole portion 125 so as to reliably contact the porous body 110 placed in the hole portion 125 after firing. At this time, a groove or the like matching the shape of the internal electrode 150 may be formed on the upper surface of the first ceramic molded body 121.

[0053] Next, the second ceramic molded body 122 is prepared and placed on the upper surface of the first ceramic molded body 121 on which the internal electrode 150 and the porous body 110 are placed. The second ceramic molded body 122 serves as a protective layer that covers the internal electrode 150 and the via 130. The second ceramic molded body 122 is preferably in the form of a flat plate. The second ceramic molded body 122 may be placed on the upper surface of the first ceramic molded body 121 after being formed as a molded body, or may be formed into the second ceramic molded body 122 by filling the upper surface of the first ceramic molded body 121 with an appropriate amount of granulated ceramic powder and subjecting it to a pressure treatment.

[0054] Next, the second internal electrode 152 is prepared and placed on the lower surface of the first ceramic molded body 121 so as to overlap the hole portion 125. In this embodiment, the internal electrode 150 and the second internal electrode 152 may be made of the same material or different materials and shapes depending on the application. In addition, one of the internal electrodes may be a wiring electrode for electrically connecting the via 130 to the terminal 180. The prepared second internal electrode 152 is placed so as to overlap the hole portion 125 so as to reliably contact the porous body 110 placed in the hole portion 125 after firing. At this time, a groove or the like matching the shape of the second internal electrode 152 may be formed on the lower surface of the first ceramic molded body 121 or the upper surface of the third ceramic molded body 123 described later.

[0055] Next, the third ceramic molded body 123 is prepared and placed on the lower surface of the first ceramic molded body 121 on which the second internal electrode 152 and the porous body 110 are placed. The third ceramic molded body 123 serves as a protective layer that covers the second internal electrode 152 and the via 130. The third ceramic molded body 123 is preferably in the form of a flat plate.

[0056] The first, second and third ceramic bodies 121, 122 and 123 may be produced by the same existing method as described above. Also, various materials may be used depending on the application.

[0057] The first, second, and third ceramic molded bodies 121, 122, and 123 are fired to become one body, forming a ceramic sintered body 140 in which the two layers of internal electrodes 150, 152 and the vias 130 are embedded. The porous body 110 is fired simultaneously with the first, second, and third ceramic molded bodies 121, 122, and 123, and is embedded in the ceramic sintered body 140 to become the vias 130 that electrically connect the internal electrode 150 and the second internal electrode 152. This ensures conductivity between the internal electrodes formed in different layers that are spaced apart in the thickness direction of the electrode-embedded member. As a result, the number of holes formed from the outside of the electrode-embedded member can be minimized, and electricity can be passed through the internal electrodes, making it possible to configure, for example, a multi-zone heater. Then, the internal electrode 150 and the second internal electrode 152 are electrically connected to the terminal 180. The number of terminals 180, i.e., the number of terminal connection positions of the electrode-embedded member 200, may be three or more.

[0058] Furthermore, as in the second embodiment, when the electrode-embedded member 200 is used as a heater, it may be joined to the shaft 170 after firing. This makes it possible to make a heater with a shaft. The shape, material, etc. of the shaft 170 are the same as those in the second embodiment.

[0059] Furthermore, when connecting the second internal electrode 152 and the terminal 180, a metal pellet 160 may be placed at the terminal connection position on the upper surface of the third ceramic molding 123. In this case, a recess for placing the pellet 160 may be provided on the upper surface of the third ceramic molding 123. The pellet 160 may also be placed between the internal electrode 150 or the second internal electrode 152 and the porous body 110. The material, size, etc. of the pellet 160 are the same as those in the second embodiment.

[0060] In this manner, it is possible to manufacture an electrode-embedded member 200 having a plurality of internal electrodes 150, 152 and vias 130. The method for manufacturing an electrode-embedded member of the present invention can manufacture an electrode-embedded member in which even a large-diameter via is completely embedded in the ceramic sintered compact without causing defects such as cracks in the ceramic sintered compact, and can handle large currents.

[0061] (Modification) Fig. 12 is a cross-sectional view showing a modified example of the heater of the third embodiment. As shown in Fig. 12, the position of the via 130 can be set to a position that is independent of the position of the terminal 180. This allows the electrode-embedded member 200 to have various configurations, expanding the range of applications.

[0062] [Configuration of electrode embedding material] Next, an electrode-embedded member 200 according to this embodiment will be described. Fig. 13 is a cross-sectional view showing an example of the electrode-embedded member 200 of this embodiment. Fig. 14 is a cross-sectional view showing a modified example of the electrode-embedded member 200 of this embodiment. Figs. 13 and 14 differ only in the position of the via 130. The electrode-embedded member 200 includes a base 190, a plurality of internal electrodes 150, 152, and a via 130.

[0063] The base 190 is formed of a ceramic sintered body. Various materials can be used for the material of the base 190 depending on the application. For example, Al2O3, AlN, Si3N4, SiC, etc. can be used. The shape of the base 190 can be various shapes depending on the application, such as an electrostatic chuck, a heater, etc.

[0064] The internal electrodes 150, 152 are embedded in a plurality of layers inside the base 190. The plurality of layers are surfaces inside the base 190 that are substantially parallel to the wafer placement surface 192 of the base 190. The internal electrodes 150, 152 may have any number of layers. FIG. 13 shows an example having two layers of internal electrodes 150, 152. The internal electrodes 150, 152 may have various shapes, such as a mesh shape or a foil shape, depending on the application. In addition, the materials may be various materials, such as molybdenum and tungsten, depending on the application. The internal electrodes 150, 152 may be made of the same material or different materials depending on the application. In addition, the internal electrodes 150 or 152 may be used as conductive wiring electrodes for electrically connecting the vias 130 to the terminals 180.

[0065] The vias 130 are embedded inside the base 190 and electrically connect the internal electrodes 150, 152. This ensures electrical conductivity between the internal electrodes 150, 152 formed in different layers. As a result, current can be passed through the internal electrodes 150, 152 while minimizing holes formed from the outside of the electrode-embedded member 200, making it possible to configure, for example, a multi-zone heater. The number of terminals 180, i.e., the terminal connection positions of the electrode-embedded member 200, may be three or more.

[0066] The via 130 is formed of tungsten, molybdenum, or a material containing at least one of them. The via 130 is formed in a columnar shape with a maximum diameter of 1.0 mm or more and a height of 1.0 mm or more. The maximum diameter of the via 130 is more preferably 1.5 mm or more, and the height is more preferably 3.0 mm or more. This allows a larger current to pass through the large-shaped via 130 between different layers that are separated by a distance in the thickness direction of the electrode-embedded member even in the outer periphery of the base 190 (for example, the outer region of the shaft when a shaft is present). It is not necessary to set an upper limit for the maximum diameter and height of the via 130, but considering the size used as a via, for example, the maximum diameter can be 15 mm or less and the height can be 30 mm or less. The relative density of the via 130 is preferably greater than 80%, more preferably 90% or more, and even more preferably 95% or more. The porous body 110 is preferably cylindrical.

[0067] When there is one via 130, it is preferable that the via 130 is embedded inside the base 190 and has no portion exposed from the base 190. When there are multiple vias 130, it is preferable that at least one of them is embedded inside the base 190 and has no portion exposed from the base 190.

[0068] A metal pellet 160 may be disposed at a terminal connection position for connecting a terminal 180 for electrically connecting the electrode-embedded member 200 to the outside, or between the internal electrode 150 and the via 130. The material, size, etc. of the pellet 160 are the same as those described above.

[0069] The electrode-embedding member 200 of the present invention can be made into an electrode-embedding member having such a configuration, which was previously difficult to achieve, and as a result, it is possible to pass a larger current through a large-sized via. This makes it possible to apply the electrode-embedding member to a variety of applications.

[0070] [Example] Example 1 According to the manufacturing method of the second embodiment, a heater for heating a wafer used in a semiconductor manufacturing device was manufactured by a hot press method. First, a raw material powder mainly composed of AlN to which an organic binder was added was pressed to produce a first ceramic molded body having a diameter of 300 mm and a thickness of 10 mm, a second ceramic molded body having a diameter of 300 mm and a thickness of 10 mm, and a third ceramic molded body having a diameter of 300 mm and a thickness of 10 mm. Next, a degreasing process was performed in an atmosphere of 500°C or more in air.

[0071] Next, a through hole (hole portion) of Φ2 mm for forming a via was opened in the first ceramic molded body. A porous body was also prepared. In the case of uniaxial hot press sintering, the volume (i.e., thickness) of the AlN ceramic molded body after sintering is about 60%, so the size of the hole portion of the first ceramic molded body after sintering is about Φ2 mm x 6 mm. Therefore, for example, when a porous body with a relative density of 75% is used and a via with a height of 6 mm is formed after sintering, a cylindrical porous body with a height of Φ2 mm and a height of 6 mm to 8 mm may be used, taking into consideration that the height will decrease by about 25% at most. As a result, the dimensions of the hole after shrinkage of the ceramic sintered body after sintering and the dimensions of the porous body after sintering shrinkage are approximately the same, and a via of about Φ2 mm x 6 mm is formed in the ceramic sintered body. As a result, there are no cracks around the via, and the porous body is sufficiently densified as close to the upper limit of the range, so that a via with sufficiently low electrical resistance is formed. In this example, a porous body having a relative density of 75%, a diameter of 2 mm, and a height of 7.2 mm was prepared, and the prepared porous body was inserted into the hole.

[0072] Next, an internal electrode was prepared. The internal electrode was a heater electrode made by cutting a Mo mesh into a specified shape. A groove in which the internal electrode was placed was machined in the first ceramic molded body. The prepared internal electrode was then placed in the groove of the first ceramic molded body in which the porous body was inserted into the hole, to form a first layer.

[0073] Next, a W pellet was prepared. The dimensions of the W pellet were Φ5mm and thickness 0.5mmt. A groove was formed in the upper surface of the third ceramic compact between the via and the terminal to place the W pellet therein. The W pellet was then placed in the groove of the third ceramic compact to form the third layer. Here, the W pellet was made of a bulk tungsten body, and served as a pad to which the terminal was brazed after firing. This allowed the terminal and heater electrode (internal electrode) to be electrically connected via the pellet and the via.

[0074] The third layer thus produced was superimposed under the first layer, and the second ceramic molded body was superimposed on the top surface of the first layer as the second layer, and then uniaxial hot press sintering was performed in a nitrogen atmosphere of 1800°C or higher and 1 MPa or higher to integrate them. The W pellet embedded in the sintered ceramic body was exposed by processing. A shaft was also joined to the bottom surface of the heater. Finally, a Φ4mm Ni terminal was brazed to the exposed pellet to complete the heater with a shaft of Example 1.

[0075] Example 2 A heater was produced under the same conditions as in Example 1, except that the diameter of the through hole for forming a via provided in the first ceramic molded body and the relative density of the porous body were changed. That is, a heater was produced using a through hole (hole) with a diameter of 1.5 mm for forming a via, a porous body with a relative density of 65%, and a cylindrical porous body with a diameter of 1.5 mm and a height of 7.8 mm.

[0076] Example 3 A heater was produced under the same conditions as in Example 1 above, except that the diameter of the through hole for forming a via provided in the first ceramic molded body, and the material and relative density of the porous body were changed. That is, a heater was produced using a through hole (hole) for forming a via with a diameter of 1.5 mm, a porous body made of Mo, with a relative density of 80%, and a cylindrical porous body with a diameter of 1.5 mm and a height of 6.8 mm.

[0077] (Functional evaluation) A current of 20 A was applied to the heater electrodes of the heaters fabricated in Examples 1 to 3, and the heater surface temperature was observed with an infrared camera. As a result of the observation, it was confirmed that no hot spots occurred even directly above the vias in any of Examples 1 to 3, and localized heat generation in the vias was suppressed.

[0078] (Cross-section observation) After the functional evaluation, the ceramic sintered body and the via of the heater of Examples 1 to 3 were cut and the cross section was observed. In all of Examples 1 to 3, no cracks were generated in the ceramic sintered body or the via at the boundary between the ceramic sintered body and the via. Furthermore, the structure of the via was sufficiently densified compared to the structure of the porous body embedded in the ceramic molded body.

[0079] (Relative via density measurement) The relative density of the vias was measured by image processing a cross-sectional SEM photograph (magnification 2000 times) of the vias to calculate the area ratio of the pores, and then calculating the relative density as 100% - the area ratio of the pores. As a result, the relative density of the vias in Example 1 was 90%, in Example 2 it was 88%, and in Example 3 it was 92%. Commercially available software such as Image-Pro can be used for image processing.

[0080] From the above, it was confirmed that the electrode-embedded member of the present invention can handle a large current, and that the manufacturing method of the present invention can manufacture such an electrode-embedded member.

[0081] 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]

[0082] 100 Ceramic sintered body with vias 110 Porous materials 120 Ceramic Moldings 121 First ceramic molded body 122 Second ceramic molding 123 The third ceramic molding 125 Hole 127 Terminal hole 130 Beer 140 Sintered ceramics 150 Internal electrode 152 Second internal electrode 160 pellets 170 Shaft 180 Terminals 190 Base 192 Wafer placement surface 200 Electrode embedding member

Claims

1. A method for manufacturing a ceramic sintered body having a via, comprising the steps of: preparing a porous body made of tungsten, molybdenum, or a material containing at least one of them, the porous body being sintered to become the via; A step of preparing a flat-plate-shaped first ceramic molded body and providing a hole in the first ceramic molded body in which the porous body is to be disposed; Preparing a second ceramic molded body; placing the porous body in the hole; placing the second ceramic molded body on an upper surface of the first ceramic molded body on which the porous body is placed; Firing the first and second ceramic bodies in which the porous body is disposed; Including, In the firing step, the first and second ceramic compacts are integrated to form the ceramic sintered body, A method for manufacturing a ceramic sintered body, characterized in that in the firing step, the porous body is fired simultaneously with the first and second ceramic molded bodies to become the vias embedded in the ceramic sintered body.

2. The porous body is disposed in the hole portion without any gaps, 2. The method for producing a ceramic sintered body according to claim 1, wherein the sintering step comprises uniaxial hot press sintering in which pressure is applied to the porous body in a height direction.

3. 3. The method for producing a ceramic sintered body according to claim 1, wherein the porous body is formed into a cylindrical shape having a maximum diameter of 1.0 mm or more and a height of 1.0 mm or more after the step of sintering the ceramic molded body.

4. A method for manufacturing an electrode-embedded member having a via, comprising the steps of: preparing a porous body made of tungsten, molybdenum, or a material containing at least one of them, the porous body being turned into the via by firing; A step of preparing a flat-plate-shaped first ceramic molded body and providing a hole in the first ceramic molded body in which the porous body is to be disposed; Preparing a second ceramic molded body; placing the porous body in the hole; preparing an internal electrode and disposing the internal electrode on an upper surface of the first ceramic molded body so as to overlap the hole; placing the second ceramic molded body on an upper surface of the first ceramic molded body on which the internal electrode and the porous body are placed; and firing the first and second ceramic molded bodies in which the porous body and the internal electrodes are arranged, In the firing step, the first and second ceramic compacts are integrated to form a ceramic sintered body, A method for manufacturing an electrode-embedded member, characterized in that in the firing step, the porous body is fired simultaneously with the first and second ceramic molded bodies, and becomes the via that is embedded in the ceramic sintered body and electrically connected to the internal electrode.

5. A method for manufacturing an electrode-embedded member having a via, comprising the steps of: preparing a porous body made of tungsten, molybdenum, or a material containing at least one of them, the porous body being turned into the via by firing; A step of preparing a flat-plate-shaped first ceramic molded body and providing a hole in the first ceramic molded body in which the porous body is to be disposed; Preparing a second ceramic molded body and a third ceramic molded body; placing the porous body in the hole; preparing an internal electrode and disposing the internal electrode on an upper surface of the first ceramic molded body so as to overlap the hole; placing the second ceramic molded body on an upper surface of the first ceramic molded body on which the internal electrode and the porous body are placed; preparing a second internal electrode and disposing the second internal electrode on a lower surface of the first ceramic molded body so as to overlap the hole; placing the third ceramic molded body on a lower surface of the first ceramic molded body on which the second internal electrode and the porous body are placed; and firing the first, second, and third ceramic molded bodies in which the porous body, the internal electrode, and the second internal electrode are arranged, the hole penetrates the first ceramic body, In the firing step, the first, second, and third ceramic molded bodies are integrated into a ceramic sintered body, a first internal electrode and a second internal electrode electrically connected to each other; and a porous body that is embedded in the ceramic sintered body and that electrically connects the first internal electrode and the second internal electrode to each other.

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