Electrode-embedding member and method for manufacturing the same

Abstract

To provide an electrode embedded member that hardly has deterioration of a connection member and a cushioning member and also hardly decreases in strength of a terminal structure, and a method of manufacturing the same.SOLUTION: The present invention relates to an electrode embedded member 100, which comprises: a flat plate type base body 110 made of a ceramic sintered body; an electrode 120 embedded in the base body 110; a connection member 130 electrically connected to the electrode 120 and embedded in the base body 110; a terminal 140 supplying electricity to the electrode 120; a cushioning member 150 arranged between the connection member 130 and the terminal 140; and a solder material 160 fixing the cushioning member 150 and the terminal 140, wherein the solder material 160 consists principally of Au, and includes Fe by 4 atoms% or larger in a surface layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electrode-embedding member and a method for manufacturing the same. [Background technology]

[0002] BACKGROUND ART Conventionally, electrode-embedded members such as susceptors, electrostatic chucks, and ceramic heaters, in which electrodes are embedded in a ceramic sintered body, have been proposed as components for semiconductor manufacturing equipment.

[0003] Patent Document 1 discloses a ceramic structure that includes a first metal member joined to a conductive member with a brazing material and having an average linear expansion coefficient equal to or greater than that of the conductive member, one or more second metal members having an average linear expansion coefficient greater than that of the first metal member, and a metal terminal joined to the second metal member and having an average linear expansion coefficient greater than that of the second metal member, and that can prevent cracks from occurring in the ceramic substrate or the conductive member even when used for a long period of time. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-182683 Summary of the Invention [Problem to be solved by the invention]

[0005] As shown in Patent Document 1, conventionally, attention has been paid to the linear expansion coefficient of the material that constitutes the electrode-embedded member, and soldering has been performed with a buffer material interposed between them. In other words, cracks in the terminal structure have been suppressed from a mechanical standpoint.

[0006] However, when electrode-embedding members having these structures are used in actual processes, oxygen from the environment causes oxidation of the connecting members and buffer members from the surface to the inside, causing deterioration of the strength of these members themselves. In other words, the strength deterioration occurs due to chemical corrosion. As a result, the strength of the terminal structure deteriorates, causing the terminal to fall off or poor electrical contact. Therefore, a terminal structure that can suppress such problems has been desired.

[0007] The inventors discovered that by including a predetermined amount or more of Fe in the brazing material, deterioration of the connecting members and buffer members is unlikely to occur even when the electrode-embedded member is used in an environment where oxygen is present, and the strength of the terminal structure is unlikely to decrease, and thus completed the present invention.

[0008] In other words, the present invention has been made in consideration of the above circumstances, and aims to provide an electrode-embedding member that is less likely to cause deterioration of connecting members and cushioning members and is less likely to reduce the strength of the terminal structure, and a method for manufacturing the same. [Means for solving the problem]

[0009] (1) In order to achieve the above object, the present invention provides an electrode-embedding member, comprising: a flat-plate-shaped substrate made of a ceramic sintered body; an electrode embedded in the substrate; a connection member electrically connected to the electrode and embedded in the substrate; a terminal for supplying electricity to the electrode; a buffer member disposed between the connection member and the terminal; and a brazing material for fixing the buffer member and the terminal, the brazing material containing Au as a main component, A region of 20 μm or less from the surface of the brazing material Fe at 4 atoms or more in the surface layer and an oxide of Fe is formed on the surface of the brazing material. It is characterized by the following.

[0010] In this way, by including 4 atoms% or more of Fe in the surface layer of the brazing material after brazing, oxidation of the connecting members and buffer members is suppressed, which in turn suppresses deterioration in the strength of the connecting members and buffer members and maintains the strength of the terminal structure.

[0012] In this way, by forming an oxide of Fe on the surface of the brazing material, oxidation of the connecting member and the buffer member is further suppressed.

[0013] ( 2 ) In the electrode-embedding member of the present invention, the brazing filler metal is characterized in that, in an intensity ratio of characteristic X-rays of O and Fe obtained by EPMA analysis or EDX analysis of a cross section perpendicular to the surface of the brazing filler metal, the value at the surface of the brazing filler metal is at least twice the value at the inside of the brazing filler metal.

[0014] In this way, in the intensity ratio of the characteristic X-rays of O and Fe obtained by EPMA analysis or EDX analysis of a cross section perpendicular to the surface of the brazing material, the value at the surface of the brazing material is at least twice the value inside the brazing material, thereby further suppressing oxidation of the connecting members and buffer members.

[0015] ( 3 In the electrode-embedding member of the present invention, the buffer member contains Fe.

[0016] In this way, since the buffer member contains Fe, even if the brazing material does not contain Fe, Fe is dissolved into the brazing material during brazing, and as a result, the brazing material after brazing contains Fe, which can be used as a raw material for oxide films, etc.

[0017] ( 4 ) Furthermore, in the electrode-embedding member of the present invention, the buffer member includes a first buffer member arranged on the connection member side and a second buffer member arranged on the terminal side, and the second buffer member is characterized in that it has Fe as its main component.

[0018] In this way, by using the second buffer member containing Fe as a main component, even if the brazing material does not contain Fe, the brazing material after brazing will contain a sufficient amount of Fe.

[0019] ( 5Furthermore, the method for manufacturing an electrode-embedding member of the present invention is a method for manufacturing an electrode-embedding member, which includes a flat-plate-shaped base made of a ceramic sintered body, an electrode embedded in the base, and a connection member electrically connected to the electrode and embedded in the base, and includes the steps of: preparing an electrode-embedding member precursor having a terminal hole formed therein through which at least a part of one main surface of the connection member is exposed; preparing a buffer member and a terminal, and arranging the buffer member and the terminal in the terminal hole of the electrode-embedding member precursor; and brazing the buffer member and the terminal arranged in the terminal hole by brazing them with the brazing material, wherein the brazing material after the brazing step is A region of 20 μm or less from the surface of the brazing material The components and size of the buffer member prepared in the disposing step or the area in contact with the brazing material are adjusted, or the components of the brazing material prepared in the brazing step are adjusted so that the surface layer contains 4 atoms% or more of Fe. The brazing material after the brazing step is heated to form an oxide of Fe on the surface of the brazing material. It is characterized by the fact that

[0020] In this way, by adjusting the composition and size of the buffer material prepared in the placement process or the area in contact with the buffer material, or by adjusting the composition of the buffer material prepared in the brazing process, so that the surface layer of the brazing material after the brazing process contains 4 atoms% or more of Fe, an oxide film of Fe is formed on the surface of the brazing material (at the boundary with the external environment) during use of the electrode-embedding member, suppressing oxidation of the connecting member and buffer material. As a result, deterioration in the strength of the connecting member and buffer material is suppressed, and the strength of the terminal structure is maintained. [Effects of the Invention]

[0021] According to the present invention, it is possible to configure an electrode-embedding member in which the connecting member and buffer member are less likely to deteriorate and the strength of the terminal structure is less likely to decrease. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 2 is a cross-sectional view showing an example of an electrode-embedded member according to the embodiment. [Figure 2]2 is an enlarged partial cross-sectional view showing a terminal structure of the electrode-embedding member of FIG. 1. FIG. [Figure 3] 10 is an enlarged partial cross-sectional view showing a terminal structure of a modified example of the electrode-embedding member according to the embodiment. FIG. [Figure 4] 1 is a flowchart illustrating an example of a method for manufacturing an electrode-embedded member according to an embodiment. [Figure 5] 1 is a flowchart illustrating an example of a method for manufacturing an electrode-embedded member according to an embodiment. [Figure 6] 1(a) to 1(d) are cross-sectional views each showing a schematic diagram of one stage in the manufacturing process of an electrode-embedded member according to an embodiment. [Figure 7] 3(a) to 3(c) are cross-sectional views each showing a schematic diagram of one stage in the manufacturing process of an electrode-embedded member according to an embodiment. [Figure 8] 1 is a table showing the manufacturing conditions and measurement results of Examples and Comparative Examples. DETAILED DESCRIPTION OF THE INVENTION

[0023] Next, an embodiment of the present invention will be described with reference to the drawings. To facilitate understanding of the description, the same reference numerals are used to designate the same components in the drawings, and duplicated descriptions will be omitted. Note that in the configuration diagrams, the size of each component is shown conceptually and does not necessarily represent the actual dimensional ratio.

[0024] [Embodiment] [Configuration of electrode embedding material] First, the configuration of an electrode-embedding member according to this embodiment will be described. Fig. 1 is a cross-sectional view showing an example of an electrode-embedding member according to this embodiment. Fig. 2 is a partial cross-sectional view showing an enlarged terminal structure of the electrode-embedding member of Fig. 1. An electrode-embedding member 100 according to this embodiment includes a base 110, an electrode 120, a connecting member 130, a terminal 140, a buffer member 150, and a brazing material 160. The electrode-embedding member 100 is applied to heaters, electrostatic chucks, etc.

[0025] The base 110 is made of a ceramic sintered body and is formed in a flat plate shape, with one main surface having a mounting surface 112 on which a substrate is placed. Various materials can be used for 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, such as a disk, a polygonal shape, or an elliptical shape.

[0026] The electrode 120 is embedded in the substrate 110. The electrode 120 can be made of Mo, W, or the like. The electrode 120 is preferably made of a mesh woven with wires. The wires forming the mesh preferably have a diameter of 0.02 mm or more and 0.15 mm or less. By using sufficiently thin wires to form the electrode 120, the risk of cracking of the wires during sintering can be further reduced. Furthermore, even if the ceramic on top of the electrode 120 is formed as a thin insulating layer, the risk of cracks occurring in the insulating layer can be further reduced.

[0027] The base 110 may be provided with a plurality of electrodes. For example, by providing a heater electrode and an electrostatic attraction electrode, the electrode-embedded member 100 can be used as a heater-equipped electrostatic chuck.

[0028] The connection member 130 is electrically connected to the electrode 120 and is embedded in the base 110. This allows electricity to be supplied to the electrode 120 via the connection member 130. The connection member 130 can be made of Mo, W, or the like.

[0029] The thickness of connecting 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 drilling terminal holes 142 for connecting terminals 140 to base 110. If it is more than 5 mm, there is an increased risk of cracks occurring in base 110 due to the difference in shrinkage rate between connecting member 130 and the ceramic of base 110 during firing and the difference in thermal expansion rate during use, since connecting member 130 is embedded in base 110.

[0030] The terminal 140 is connected to an external power source (not shown) and supplies electricity to the electrode 120. The terminal 140 can be made of Ni or the like. The terminal 140 is electrically connected to and fixed to the electrode 120, the connecting member 130, or the buffer member 150 by the brazing material 160.

[0031] The buffer member 150 is disposed between the connection member 130 and the terminal 140. Disposed between the connection member 130 and the terminal 140 means that the buffer member 150 is disposed in a region of the electrode-embedding member 100 below the lower surface of the connection member 130 and above the upper end of the terminal 140. It is preferable that a brazing material 160 be present between the lower surface of the connection member 130 and the upper surface of the buffer member 150, and between the lower surface of the buffer member 150 and the upper end of the terminal 140.

[0032] The buffer member 150 can be made of, for example, W, Mo, Kovar, Invar, Super Invar, Niresist, etc. The thickness of the buffer member 150 is preferably 0.2 mm or more and 2 mm or less.

[0033] The connecting member 130 and the buffering member 150 may be made of the same material. In this way, the connecting member 130 is embrittled because it is embedded in the base 110 and fired, but since there is almost no difference in the expansion coefficients between the connecting member 130 and the buffering member 150, stress is less likely to act on the connecting member 130, making the connecting member 130 less likely to break. On the other hand, although there is a difference in the expansion coefficients between the buffering member 150 and the terminal 140, the buffering member 150 is not fixed in position during brazing and is fluid, so stress is less likely to occur between the buffering member 150 and the terminal 140. This makes it possible to suppress cracks in the terminal structure from a mechanical standpoint.

[0034] The connecting member 130 and the buffer member 150 may be made of different materials. In this case, it is preferable to increase the linear expansion coefficients of the connecting member 130, buffer member 150, and terminal 140 in this order. This makes it possible to suppress cracks in the terminal structure from a mechanical standpoint. Increasing the linear expansion coefficients in this order includes cases where the linear expansion coefficients of the two members are equal.

[0035] 3 is an enlarged partial cross-sectional view showing a terminal structure of a modified example of the electrode-embedding member 100 according to the embodiment. As shown in FIG. 3, the buffer member 150 preferably includes a first buffer member 151 disposed on the connecting member 130 side and a second buffer member 152 disposed on the terminal 140 side. In this case, it is preferable that the linear expansion coefficients of the connecting member 130, the first buffer member 151, the second buffer member 152, and the terminal 140 increase in this order. This makes it possible to suppress cracks in the terminal structure from a mechanical standpoint.

[0036] Furthermore, when the buffer member 150 is configured to include a first buffer member 151 and a second buffer member 152, the connecting member 130 and the first buffer member 151 may be configured from the same material, and the linear expansion coefficients of the first buffer member 151, the second buffer member 152, and the terminal 140 may increase in order.

[0037] The brazing material 160 fixes the buffer member 150 and the terminal 140. The brazing material 160 electrically connects the connection member 130, the terminal 140, or the buffer member 150 to each other.

[0038] The brazing material 160 is primarily composed of Au, and contains 4 atoms% or more of Fe in the surface layer. This makes it easier for an oxide film of Fe to form on the surface of the brazing material 160 (at the boundary with the external environment) during use of the electrode-embedding member 100, or Fe selectively bonds with oxygen, thereby suppressing oxidation of the connecting member 130 and the buffer member 150. As a result, deterioration in the strength of the connecting member 130 and the buffer member 150 is suppressed, and the strength of the terminal structure is maintained.

[0039] The brazing material 160 containing Au as a main component means that the concentration of Au contained in the brazing material 160 is 80 wt% or more. Furthermore, the brazing material 160 containing 4 atoms% or more of Fe in the surface layer means that the concentration of Fe in the brazing material 160 in the surface layer of the brazing material 160 after brazing (a region 20 μm or less from the surface of the brazing material 160) is 4 atoms% or more. This makes it easier for an oxide film of Fe to be formed on the surface of the brazing material 160 during use of the electrode-embedding member 100.

[0040] The Fe contained in the brazing material 160 may be added to the brazing material 160 before brazing. This makes it easy to include a predetermined amount of Fe in the brazing material 160. When adding Fe to the brazing material 160 before brazing, if elution of Fe from other components is not a consideration, it is preferable to add Fe to the brazing material 160 so as to achieve a predetermined concentration of, for example, 0.16 wt% to 10 wt% inclusive.

[0041] Furthermore, the Fe contained in the brazing material 160 may be dissolved from other components into the brazing material 160 during brazing, and may be contained in the brazing material 160 after brazing. This is because even if the Fe is dissolved into the brazing material 160 during brazing, the formation of an oxide film of Fe and selective bonding with oxygen may occur during use of the electrode-embedded member 100.

[0042] When the brazing material 160 is configured so that Fe is eluted during brazing, the amount of Fe originally contained in or added to the brazing material 160 may be zero, and the total amount of Fe contained in the brazing material 160 after brazing may be Fe eluted from other components. Alternatively, the brazing material 160 may be configured so that a smaller amount of Fe is contained or added than the target amount, and the shortage is made up for by Fe eluted from other components.

[0043] When the buffer member 150 is configured to elute Fe into the brazing material 160 during brazing, the other component that supplies Fe is preferably the buffer member 150. That is, the buffer member 150 preferably contains Fe. When the buffer member 150 contains Fe, even if the brazing material 160 does not contain Fe, Fe is eluted into the brazing material during brazing. As a result, the brazing material 160 after brazing contains Fe, which can be used as a raw material for an oxide film, etc. In this case, in order to ensure that the brazing material 160 contains a desired amount of Fe after brazing, it is necessary to adjust the Fe concentration in the buffer member 150, the size of the buffer member 150, the area of ​​contact with the brazing material 160, and the like. When the buffer member 150 is configured to contain Fe, the buffer member 150 can be formed from, for example, W with Fe addition, Mo with Fe addition, or an alloy containing Ni, such as Kovar, Invar, Super Invar, or Niresist. This is because the inclusion of Ni facilitates the elution of Fe into the brazing material.

[0044] When Fe is eluted into the brazing material 160 during brazing and the buffer member 150 includes a first buffer member 151 and a second buffer member 152, the second buffer member preferably contains Fe as a primary component. By using a second buffer member containing Fe as a primary component, even if the brazing material does not contain Fe, a sufficient amount of Fe is contained in the brazing material 160 after brazing. Furthermore, when Fe is eluted into the brazing material 160 during brazing, the Fe concentration in the brazing material 160 after brazing varies depending on the portion. However, by using a material containing Fe as the primary component for the second buffer member 152 disposed on the terminal 140 side, the portion of the brazing material 160 near the surface contains more Fe, making it more suitable as a raw material for an oxide film, etc. When the second buffer member 152 is configured to contain Fe as a primary component, the second buffer member 152 can be formed of an alloy containing Ni, such as Kovar, Invar, Super Invar, or Niresist.

[0045] When the brazing material 160 is configured to dissolve Fe during brazing, the other component that supplies Fe may be a foil (Fe supply component) containing Fe or composed mainly of Fe, which dissolves almost entirely in the brazing material 160 during brazing. This increases the Fe concentration in the intended region of the brazing material 160 regardless of the buffer member 150, allowing the material to be more appropriately used as a raw material for an oxide film, etc. When an Fe supply component is used, it may be located anywhere. For example, it may be located at the position of the first buffer member 151 or the second buffer member 152. In other words, the Fe supply component may be located between the connecting member 130 and the buffer member 150, or between the buffer member 150 and the terminal 140. While other locations are possible, the Fe supply component has a certain size, and therefore, locating it in one of these locations facilitates manufacturing.

[0046] The brazing material 160 preferably has an oxide film of Fe on the surface thereof, which further suppresses oxidation of the connection member 130 and the buffer member 150.

[0047] In the brazing material 160, the intensity ratio of characteristic X-rays of O (oxygen) to Fe (iron) obtained by EPMA analysis or EDX analysis of a cross section perpendicular to the surface is preferably such that the value at the surface of the brazing material 160 (ratio of characteristic X-ray spectra (O intensity / Fe intensity)) is at least twice the value at the interior of the brazing material 160. This further suppresses oxidation of the connecting member 130 and the buffer member 150. The surface layer of the brazing material 160 refers to a region 20 μm or less from the surface of the brazing material 160, and the interior of the brazing material 160 refers to a region 100 μm or more away from the surface of the brazing material 160.

[0048] In the electrode embedding member 100 of the present invention, the connecting member 130 and the buffer member 150 are less likely to deteriorate, and the strength of the terminal structure is less likely to decrease. As a result, the terminal 140 is less likely to fall off or electrical contact failures are less likely to occur.

[0049] [Method for manufacturing electrode-embedded members] Next, a method for manufacturing an electrode-embedded member according to this embodiment will be described. Figures 4 and 5 are flowcharts showing an example of a method for manufacturing an electrode-embedded member according to this embodiment. As shown in Figure 4, the method for manufacturing an electrode-embedded member according to this embodiment includes a preparation step S1, an arrangement step S2, and a brazing step S3.

[0050] 5, the preparation step S1 includes a green body forming step T1, a degreasing step T2, an electrode preparing step T3, a laminate forming step T4, a firing step T5, and a terminal hole processing step T6. Note that, although the following describes a manufacturing method using a green body hot pressing method in which green bodies are stacked, in the present invention, the Fe concentration in the brazing material after the brazing step S3 is important, and therefore each step may be replaced with a different method as long as it can adjust this concentration.

[0051] 6(a) to 6(d) and 7(a) to 7(c) are cross-sectional views each showing a schematic diagram of a step in the manufacturing process of an electrode-embedding member according to an embodiment of the present invention. Fig. 6 and Fig. 7 show the manufacturing process of the electrode-embedding member of Fig. 1. First, the preparation step S1 will be described in detail, and the steps from the compact formation step T1 to the terminal hole processing step T6 will be explained.

[0052] In the compact formation step T1, multiple ceramic compacts 11 and 12 are formed from ceramic raw material powder. While the ceramic compact is shown as being divided into two components in FIG. 6, it may be divided into three or more components depending on the design. For example, additives such as binders, plasticizers, and dispersants may be added to and mixed with the ceramic raw material powder to produce a slurry. Granules (granulated powder) are then formed by spray drying or other methods, and the resulting mixture is then pressure-molded to form multiple ceramic compacts 11 and 12. Various materials can be used for the ceramic raw material powder depending on the application of the electrode-embedded member. Examples of suitable materials include AlN, Al2O3, Si3N4, and SiC. Sintering aid powders may also be added to the ceramic raw material powder as needed.

[0053] The ceramic raw material powder preferably has a 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.

[0054] The mixing method may be either wet or dry, and a mixer such as a ball mill or a vibration mill may be used. Furthermore, known methods such as uniaxial pressing or cold isostatic pressing (CIP) may be used as the molding method. The method for forming the ceramic compact is not limited to pressure molding; for example, green sheet lamination or slip casting may also be used, and the ceramic compact can be manufactured by appropriately degreasing or further calcining these. Furthermore, a laminate may be formed by powder hot pressing.

[0055] After forming, the ceramic molded bodies 11 and 12 may be machined to adjust the shape of the molded bodies. Also, as shown in FIG. 6(b), one surface of the ceramic molded body 12 (the surface to be joined with another ceramic molded body 11) may have a recess formed thereon in a shape that matches the shape of the electrode 120 and the connecting member 130. The recess may be formed in the ceramic molded body 11, or may be formed in both. The machining may be performed after degreasing.

[0056] In the debinding step T2, the ceramic molded bodies 11 and 12 are debound at a predetermined temperature or higher for a predetermined time or longer to produce a plurality of ceramic debound bodies 21 and 22. The ceramic molded bodies 11 and 12 are heat-treated, for example, at a temperature of 400°C to 800°C to produce the ceramic debound bodies 21 and 22. The debinding time is preferably 1 hour to 120 hours. An atmospheric furnace or a nitrogen atmosphere furnace can be used for debinding, but an atmospheric furnace is preferred to remove unnecessary components from the binder.

[0057] In the electrode preparing step T3, electrodes 120 made of Mo, W, or the like and cut into a predetermined shape, and connecting members 130 made of Mo, W, or the like and processed into a predetermined shape are prepared.

[0058] In the laminate formation process step T4, the prepared electrodes 120, connecting members 130, and multiple ceramic degreased bodies 21, 22 are combined to form a laminate 30 shown in Figure 6(c), which is formed in a flat plate shape and has the electrodes 120 and connecting members 130 embedded therein.

[0059] In the firing step T5, the formed laminate 30 is uniaxially pressurized and fired in a direction perpendicular to the main surface (mounting surface) to obtain the fired body 40 shown in FIG. 6(d). The pressure is preferably 1 MPa or more. The firing temperature and firing time vary depending on the type of ceramic used as the base material. For example, when the base is made of AlN, the firing temperature is preferably 1500°C to 2000°C. The firing time is preferably 1 hour to 12 hours. 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 into a ceramic sintered body, which is integrated to obtain the fired body 40 in which the electrodes 120 and connecting members 130 are embedded.

[0060] In the terminal hole processing step T6, the sintered body 40 is processed by grinding, polishing, etc. to form a predetermined outer shape and the surface roughness of the mounting surface 112 is set within a predetermined range, thereby producing the electrode embedding member precursor 50 shown in Fig. 7(b). In addition, terminal holes 142 of a predetermined shape are drilled from the back side of the sintered body 40 to the terminal positions, reaching the connecting member 130.

[0061] A calcination step may be performed between the degreasing step T2 and the laminate formation step T4. When the calcination step is performed, the degreased ceramic body is calcined to produce a calcined ceramic body. This allows for higher dimensional accuracy of the outer shape of the electrode-embedding member and the embedding positions of the electrodes and connecting members. The calcination time and temperature vary depending on the type of ceramic used for the substrate. For example, when the substrate is made of AlN, calcination is preferably performed at a temperature of 1200°C to 1700°C for 0.5 to 12 hours. The calcination atmosphere is preferably a nitrogen or inert gas atmosphere, but may also be a vacuum atmosphere. When the calcination step is performed, machining may be performed after the calcination step.

[0062] By the steps shown in the above example, it is possible to prepare an electrode-embedding member precursor 50 in a preparation step S1, which includes a flat substrate 110 made of a sintered ceramic body, an electrode 120 embedded in the substrate 110, and a connecting member 130 electrically connected to the electrode 120 and embedded in the substrate 110, with a terminal hole 142 drilled through which at least a portion of one main surface of the connecting member 130 is exposed. Next, an arrangement step S2 and a brazing step S3 will be described.

[0063] In the arrangement step S2, the buffer member 150 and the terminal 140 are prepared, and the buffer member 150 and the terminal 140 are arranged in the terminal hole 142 of the electrode-embedding member precursor 50. The buffer member 150 to be arranged may be thin, such as foil. Also, foil may be arranged in addition to the buffer member 150.

[0064] The prepared buffer member 150 may include a first buffer member 151 arranged on the connecting member 130 side and a second buffer member 152 arranged on the terminal 140 side. The first buffer member 151 or the second buffer member 152 may be thin, such as a foil. Furthermore, foil may be arranged in addition to the first buffer member 151 and the second buffer member 152.

[0065] In the brazing process step S3, a brazing material 160 containing Au as a main component is prepared, and the buffer member 150 and the terminal 140 arranged in the terminal hole 142 are brazed and fixed using the brazing material 160, thereby producing the electrode-embedding member 100 shown in Figure 7(c).

[0066] In the manufacturing method of the present invention, the composition and size of the buffer member 150 prepared in the placement step S2 or the area in contact with the brazing material are adjusted, or the composition of the brazing material 160 prepared in the brazing step S3 is adjusted, so that the brazing material 160 after the brazing step S3 contains 4 atoms% or more of Fe in the surface layer. At this time, brazing may be performed by placing an Fe supplying member such as a foil containing Fe or primarily composed of Fe, which dissolves almost entirely in the brazing material 160 during brazing. When adjusting the Fe concentration in the buffer member 150, the size of the buffer member 150, the area in contact with the brazing material, etc., for example, a larger area in contact with the brazing material is preferable, and a thinner thickness is preferable. However, if the entire amount of Fe contained in the brazing material 160 after brazing is configured to be Fe eluted from the buffer member 150, if the buffer member 150 is too thin, much of it may dissolve in the brazing material, preventing the buffer member from fulfilling its function as a buffer member after brazing. Therefore, when configured in this manner, the thickness is preferably 0.2 mm or more and 2 mm or less. Furthermore, it is preferable that the corners of the ends of the main surface are C-faceted, and that the C be 0.5 mm or more. Furthermore, it is preferable that the buffer member 150 has high wettability with the brazing material 160, and it is more preferable that the surface be roughened to Ra 1 μm or more. When using an Fe supply member, if the thickness is too thin, the amount of eluted Fe may be insufficient. Therefore, it is preferable that the thickness of the Fe supply member be 0.05 mm or more and less than 2 mm.

[0067] By doing this, it is possible to manufacture an electrode embedding member 100 in which the connecting member 130 and the buffer member 150 are less likely to deteriorate during use in the actual process, the strength of the terminal structure is less likely to decrease, and the terminal 140 is less likely to fall off or have poor electrical contact.

[0068] [Examples and Comparative Examples] Example 1 Ceramic raw material powder, mainly composed of AlN with 5 wt% Y2O3 added, was used for CIP molding (pressure 1 ton / cm 2 ) to obtain a green body ingot. This was machined to form a ceramic green body with a diameter of 340 mm and a thickness of 20 mm, and another ceramic green body with a diameter of 340 mm and a thickness of 10 mm. A recess with a diameter of 300 mm and a depth of 0.1 mm was provided on one side of the 20 mm thick ceramic green body, sharing the center of the green 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 where a terminal would be formed, for accommodating a connecting member.

[0069] Next, the ceramic compact was degreased at 550°C for 12 hours to produce a ceramic degreased body. Next, a 294mm diameter molybdenum mesh (wire diameter 0.1mm, plain weave, mesh size #50) was cut to the specified shape to prepare an electrode. Two connecting members measuring φ8mm x 0.2mm were also produced from W pellets. Next, the connecting members and electrodes were placed in the recesses of a ceramic degreased body with recesses, and sandwiched between the other ceramic degreased body to produce an electrode-embedded member precursor.

[0070] Next, the electrode-embedding member precursor was placed in a hot press furnace and heat-treated from 800°C to 1500°C for 14 hours. Next, while applying a force of 10 MPa in a direction perpendicular to the main surface (mounting surface) of the electrode-embedding member precursor, it was uniaxially hot-pressed and fired at 1800°C for 2 hours. In this way, the base with the electrodes and connecting members embedded was fired.

[0071] The entire surface was then ground and polished to form a wafer-mounting surface with a total thickness of 20 mm, an insulating layer thickness of 1.0 mm, and a surface roughness of Ra 0.4 μm. Flat-bottom holes with a diameter of φ5.5 mm were drilled from the back side of the ceramic substrate to the terminal positions, reaching the connecting members.

[0072] Next, Fe was added to the BAu-4 brazing filler metal to prepare an Au-Ni brazing filler metal containing 1 wt% Fe. A 5 mm diameter, 2 mm thick W buffer member and a 5 mm diameter, 50 mm long, cylindrical Ni power supply terminal were attached to the exposed bottom surface of the connecting member via the prepared Au-Ni brazing filler metal. Brazing was then performed using the Au-Ni brazing filler metal in a vacuum furnace at 1050°C to complete the electrode-embedded member. In this manner, the electrode-embedded member of Example 1 was produced.

[0073] Example 2 In Example 2, instead of the W buffering member used in Example 1, a first W buffering member with a diameter of 5 mm and a thickness of 2 mm and a second Kovar buffering member with a diameter of 5 mm and a thickness of 2 mm were used. The corners of the end of the main surface on the terminal side of the second buffering member were machined to C0.5 mm to increase the area in contact with the brazing material, and the surface was roughened to Ra4 μm to improve the wettability of the buffering member with the brazing material. Furthermore, instead of the Au-Ni-based brazing material containing 1 wt% Fe, a BAu-4 brazing material without added Fe was used. The electrode-embedding member of Example 2 was fabricated under the same conditions as Example 1, except for the above.

[0074] Example 3 In Example 3, instead of the W buffer member used in Example 1, a W buffer member with a diameter of 5 mm and a thickness of 2 mm containing 1 wt% Fe was used. The buffer member was processed in the same manner as the second buffer member of Example 2. In addition, instead of the Au-Ni-based brazing material containing 1 wt% Fe, a BAu-4 brazing material with no added Fe was used. Otherwise, the electrode-embedded member of Example 3 was produced under the same conditions as Example 1.

[0075] Example 4 In Example 4, instead of the W buffer member used in Example 1, a first buffer member made of W with a diameter of 5 mm and a thickness of 2 mm and containing 1 wt% Fe, and a second buffer member made of Kovar with a diameter of 5 mm and a thickness of 2 mm, were used. The second buffer member was processed in the same manner as in Example 2. In addition, instead of the Au-Ni-based brazing material containing 1 wt% Fe, a BAu-4 brazing material with no added Fe was used. The electrode-embedded member of Example 4 was fabricated under the same conditions as in Example 1, except for the above.

[0076] Example 5 In Example 5, instead of the W buffer member used in Example 1, a first buffer member made of Mo with a diameter of 5 mm and a thickness of 2 mm and a second buffer member made of Kovar with a diameter of 5 mm and a thickness of 2 mm were used. The second buffer member was processed in the same manner as in Example 2. In addition, instead of the Au-Ni-based brazing material containing 1 wt% Fe, a BAu-4 brazing material without added Fe was used. The electrode-embedded member of Example 5 was fabricated under the same conditions as in Example 1 except for the above.

[0077] Example 6 In Example 6, instead of the W connecting member used in Example 1, a Mo connecting member was embedded and fired. Furthermore, instead of the W buffer member used in Example 1, a first Mo buffer member with a diameter of 5 mm and a thickness of 2 mm and a second Kovar buffer member with a diameter of 5 mm and a thickness of 2 mm were used. The second buffer member was processed in the same manner as in Example 2. Furthermore, instead of the Au-Ni brazing material containing 1 wt% Fe, a BAu-4 brazing material with no added Fe was used. The electrode-embedding member of Example 6 was otherwise fabricated under the same conditions as in Example 1.

[0078] Example 7 In Example 7, instead of the W buffer member used in Example 1, a Kovar foil with a diameter of 5 mm and a thickness of 0.1 mm was placed as the first buffer member, and a W buffer member with a diameter of 5 mm and a thickness of 2 mm was placed as the second buffer member, and brazing was performed. In addition, instead of the Au-Ni-based brazing material containing 1 wt% Fe, a BAu-4 brazing material with no added Fe was used. Otherwise, the electrode-embedded member of Example 7 was produced under the same conditions as Example 1.

[0079] Example 8 In Example 8, a buffer member made of Ni-resist was used instead of the W buffer member used in Example 1, and brazing was performed. The buffer member was processed in the same manner as the second buffer member in Example 2. In addition, a BAu-4 brazing material without added Fe was used instead of the Au-Ni brazing material containing 1 wt% Fe. The electrode-embedded member of Example 8 was fabricated under the same conditions as Example 1 except for the above.

[0080] (Comparative Example 1) In Comparative Example 1, a BAu-4 brazing filler metal containing no Fe was used instead of the Au—Ni brazing filler metal containing 1 wt % Fe used in Example 1. Except for this, the electrode-embedding member of Comparative Example 1 was produced under the same conditions as in Example 1.

[0081] (Comparative Example 2) In Comparative Example 2, a Kovar foil with a diameter of 5 mm and a thickness of 0.03 mm was placed between the W buffer member and the terminal used in Example 1, and brazing was performed. In addition, a BAu-4 brazing material without added Fe was used instead of the Au-Ni brazing material containing 1 wt% Fe. The electrode-embedded member of Comparative Example 2 was produced under the same conditions as in Example 1 except for this.

[0082] [Performance evaluation] (Temperature cycle test) The terminals were connected to an external power source, power was applied, and the surface temperature of the electrode-embedded member mounting surface was heated to 650°C, held at that temperature for two hours, and then cooled to 200°C. This cycle was repeated 20 times. The temperature cycle test was conducted in an environment exposed to the atmosphere.

[0083] (tensile strength test) After the temperature cycle test, the base of the electrode-embedded member was fixed to a strength tester, and the terminal was pulled vertically to measure the strength at which it broke.

[0084] (Composition analysis of brazing material) The electrode-embedded material 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 section of the connecting member, electrode, buffer member, and brazing material was exposed and polished, after which the composition of the brazing material was analyzed using EPMA. Specifically, the cross section was magnified 1000 times using the EPMA device and elemental mapping of the cross section was performed. The elements detected were Fe and O. Note that composition analysis of the brazing material can also be performed using an EDX-SEM device.

[0085] Furthermore, the degree of oxidation of Fe was evaluated by measuring (O intensity / Fe intensity) from the characteristic X-ray spectrum measured from the analysis point. The area to be evaluated was a square area of ​​approximately 20 μm in size within a predetermined range (100 μm to 120 μm) of the brazing material surface layer (area 20 μm or less from the surface) and the interior of the brazing material (area 100 μm or more away from the surface).

[0086] (Measurement of the thickness of the Fe oxide on the surface) After the temperature cycle test, the cross section of the brazing material was observed under SEM (1000x magnification) and the thickness of the oxide on the surface was measured. Measurements were taken at five locations per field of view, and the average value was taken as the thickness. If the thickness was 1 μm or more, it was judged that Fe oxide had formed, and if it was less than 1 μm or it was difficult to measure, it was judged that there was no oxide.

[0087] 8 is a table showing the manufacturing conditions and measurement results of the examples and comparative examples. It was confirmed that examples 1 to 8 maintained high terminal strength after the thermal cycle test compared to comparative examples 1 and 2.

[0088] In the composition analysis of the surface layer of the brazing filler metal in Examples 1 to 8, Fe was found to be 4 atoms% or more. In contrast, in Comparative Example 1, the Fe content was below the detection limit and could be evaluated as not containing any Fe. Furthermore, in Comparative Example 2, the Fe content was 3.5 atoms%, which did not meet the standard. In cross-sectional observation, the Kovar foils in both Example 7 and Comparative Example 2 were almost completely melted. On the other hand, in Comparative Example 2, the Fe content in the surface layer of the brazing filler metal did not meet the standard. This is thought to be due to the Kovar foil in Comparative Example 2 being too thin. It is presumed that in Comparative Examples 1 and 2, the brazing filler metal did not contain Fe or contained a low amount of Fe, which caused the connecting member or buffer member to deteriorate during the thermal cycle test, resulting in a weakened terminal strength. In Examples 1 to 8, an Fe oxide film was observed on the surface of the brazing filler metal after the thermal cycle.

[0089] Furthermore, the ratio of characteristic X-ray spectra (O intensity / Fe intensity) of the surface layer of the brazing filler metals of Examples 1 to 8 was greater than the value inside the brazing filler metal, and the difference was more than twice the value inside. Furthermore, in Comparative Example 2, the value was 1.4 times. This also confirmed that an oxide film of Fe was formed on the surface of the brazing filler metal of the examples after the thermal cycle.

[0090] The above results confirmed that the electrode-embedding member of the present invention is less susceptible to deterioration of the connecting member and buffer member, and less susceptible to reduction in the strength of the terminal structure, making it less susceptible to terminal detachment and poor electrical contact. It was also confirmed that the manufacturing method of the present invention can manufacture such an electrode-embedding member.

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

[0092] 11, 12 Ceramic molding 21, 22 Ceramic degreased body 30 laminate 40 fired body 50 Electrode embedding material precursor 100 Electrode embedding member 110 Base 112 Placement surface 120 electrodes 130 Connecting member 140 terminals 142 terminal hole 150 Cushioning material 151 first buffer member 152 Second buffer member 160 Brazing material

Claims

1. An electrode-embedding member, a flat substrate made of a ceramic sintered body; an electrode embedded in the substrate; a connecting member electrically connected to the electrode and embedded in the substrate; a terminal for supplying electricity to the electrode; a buffer member disposed between the connection member and the terminal; a brazing material for fixing the buffer member and the terminal, The brazing material contains Au as a main component and contains 4 atoms% or more of Fe in a surface layer that is a region of 20 μm or less from the surface of the brazing material, An electrode-embedding member, characterized in that an oxide of Fe is formed on the surface of the brazing material.

2. 2. The electrode-embedding member according to claim 1, wherein the strength ratio of characteristic X-rays of O and Fe in the surface layer of the brazing material is at least twice the strength ratio in the interior of the brazing material as determined by EPMA analysis or EDX analysis of a cross section perpendicular to the surface of the brazing material.

3. An electrode-embedded member as described in claim 1 or claim 2, characterized in that the buffer member contains Fe.

4. The buffer member includes a first buffer member arranged on the connection member side and a second buffer member arranged on the terminal side, 4. The electrode-embedding member according to claim 1, wherein the second buffer member is mainly composed of Fe.

5. A method for manufacturing an electrode-embedded member, comprising: a preparation step of preparing an electrode-embedding member precursor, the electrode-embedding member precursor comprising a flat-plate-shaped substrate made of a ceramic sintered body, an electrode embedded in the substrate, and a connection member electrically connected to the electrode and embedded in the substrate, the electrode-embedding member precursor having a terminal hole formed therein through which at least a portion of one main surface of the connection member is exposed; an arrangement step of preparing a buffer member and a terminal, and arranging the buffer member and the terminal in the terminal hole of the electrode-embedding member precursor; a brazing step of preparing a brazing material containing Au as a main component, and brazing and fixing the buffer member and the terminal disposed in the terminal hole using the brazing material, the components and size of the buffer member prepared in the disposing step or the area in contact with the brazing material are adjusted, or the components of the brazing material prepared in the brazing step are adjusted, so that the brazing material after the brazing step contains 4 atoms% or more of Fe in a surface layer that is a region of 20 μm or less from the surface of the brazing material; The method for manufacturing an electrode-embedded member, comprising heating the brazing material after the brazing step to form an oxide of Fe on the surface of the brazing material.

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