Airtight terminal

Abstract

To provide an airtight terminal that, even when repeatedly used in a high temperature environment and a low temperature environment, reduces the likelihood of the generation of cracks in an insulating member and reduces the likelihood of the generation of particles.SOLUTION: An airtight terminal according to the present disclosure comprises: a cylindrical insulating member that has a first step part on an inner peripheral side of any one of its end faces; a columnar conductive member that is inserted into the inner peripheral side of the insulating member and is shorter in length in an axial direction than the insulating member; and a flanged annular member that is joined to an outer peripheral surface of the conductive member and a first step surface forming the first step part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a hermetic terminal. [Background technology]

[0002] Conventionally, in cooling devices that use the evaporation and condensation of a refrigerant to cool a heat-generating body such as a semiconductor element, a hermetic terminal has been used to establish electrical continuity between the semiconductor element and an external circuit. In order to reduce costs by reducing the number of joints without using expensive low-thermal expansion metals, Patent Document 1 describes a hermetic terminal that includes a center electrode made of oxygen-free copper and an insulating cylinder made of alumina ceramics.

[0003] However, there is a large difference between the average linear expansion coefficients of oxygen-free copper and alumina. Therefore, when a center electrode made of oxygen-free copper is joined to an insulating sleeve made of alumina ceramics with brazing filler metal, cracks tend to form in the insulating sleeve immediately after joining. Even if cracks do not form immediately after joining, repeated use in high- and low-temperature environments can lead to cracks in the insulating sleeve.

[0004] Furthermore, Patent Document 2 describes a boiling cooling device that houses semiconductor elements together with a refrigerant liquid in a sealed container and cools the semiconductor elements. In this boiling cooling device, a bushing is installed on the wall of the sealed container, and a through conductor that penetrates the insulating tube is joined to the outside of the sealed container of an insulating tube that is part of the bushing, and a gap is provided between the through conductor and the inner wall part of the insulating tube facing the sealed container. Patent Document 2 describes a structure in which an insulating tube is inserted into this gap to insulate the through conductor from the wall of the sealed container, and describes a tetrafluoroethylene tube as an example of the insulating tube.

[0005] However, insulating tubes such as tetrafluoroethylene tubes have low creep resistance and are prone to deterioration over time. Furthermore, insulating tubes that have deteriorated over time are prone to generating particles. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 7-245364 [Patent Document 2] Japanese Unexamined Patent Publication No. 61-168249 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0007] An object of the present invention is to provide an airtight terminal that is less likely to develop cracks in its insulating member and less likely to generate particles even when used repeatedly in high-temperature and low-temperature environments. [Means for solving the problem]

[0008] The airtight terminal of the present disclosure comprises a tubular insulating member having a first step portion on the inner circumferential side of one of its end faces, a columnar conductive member inserted into the inner circumferential side of the insulating member and having an axial length shorter than that of the insulating member, and a flanged annular member joined to the outer circumferential surface of the conductive member and the first step surface that forms the first step portion.

[0009] A cooling device according to the present disclosure includes the above-described airtight terminal.Furthermore, a plasma processing apparatus according to the present disclosure includes the above-described airtight terminal. [Effects of the Invention]

[0010] The airtight terminal according to the present disclosure, having the above-described configuration, is less likely to crack in the insulating member even when used repeatedly in high and low temperature environments. Furthermore, since the airtight terminal according to the present disclosure does not use a resin insulating tube such as a polytetrafluoroethylene tube, particles are less likely to be generated. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing an airtight terminal according to an embodiment of the present disclosure. [Figure 2] 2 is an enlarged explanatory view for explaining an area X shown in FIG. 1. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] A hermetic terminal according to one embodiment of the present disclosure will be described with reference to Figures 1 and 2. The hermetic terminal 10 according to one embodiment shown in Figure 1 includes an insulating member 1, a conductive member 2, and a flanged annular member 3. Figure 1 is a cross-sectional view showing the hermetic terminal 10 according to one embodiment.

[0013] The insulating member 1 is made of an insulating material such as ceramics. Examples of the ceramics that form the insulating member 1 include ceramics containing aluminum oxide, aluminum nitride, silicon carbide, silicon nitride, or sialon as a main component.

[0014] In this specification, the term "major component" refers to a component that accounts for 80% by mass or more of the total 100% by mass of the components that make up the ceramic. Each component contained in the ceramic can be identified using an X-ray diffractometer using CuKα radiation, and the content of each component can be determined using, for example, an ICP (Inductively Coupled Plasma) emission spectrometer or an X-ray fluorescence analyzer.

[0015] The insulating member 1 has a tubular shape, and is not limited to any particular shape. The insulating member 1 has a shape such as a cylindrical shape or a rectangular shape (e.g., a triangular, square, pentagonal, or hexagonal shape). The size of the insulating member 1 may be appropriately set depending on the device in which the airtight terminal 10 is provided. The length (axial length) of the insulating member 1 is, for example, 40 mm or more and 80 mm or less, and the outer diameter of the outermost periphery is 10 mm or more and 20 mm or less. In the case of a rectangular cylindrical shape, the outer diameter refers to the length of the longest outer edge.

[0016] 2, the insulating member 1 is provided with a first step portion 11 on the inner circumferential side of one end face. FIG. 2 is an enlarged explanatory view for explaining region X shown in FIG.

[0017] The conductive member 2 is made of a conductive material such as a metal. Examples of metals that can be used to form the conductive member 2 include carbon steel, low-alloy steel, tool steel, stainless steel, iron, copper, copper alloys, titanium, titanium alloys, molybdenum, molybdenum alloys, Fe-Ni alloys, Fe-Ni-Cr-Ti-Al alloys, Fe-Cr-Al alloys, Fe-Co-Cr alloys, Fe-Co based alloys, Fe-Co-C based alloys, Fe-Ni based alloys, and Fe-Ni-Co based alloys.

[0018] When the metal forming the conductive member 2 is copper, it is preferably oxygen-free copper, tough pitch copper, or phosphorus-deoxidized copper. In particular, when oxygen-free copper is selected, it is preferably linear crystal oxygen-free copper, single crystal high-purity oxygen-free copper, or vacuum-melted copper, each of which has a copper content of 99.995% by mass or more.

[0019] Carbon steel is an alloy of Fe and C, containing 0.02% to 2.14% by mass of C. In addition to C, it also contains Si, Mn, P, and S. Examples of such carbon steel include S10C, S12C, S15C, S17C, S20C, S22C, S25C, S28C, S30C, S33C, S35C, S38C, S40C, S43C, S45C, S48C, S50C, S53C, S55C, S58C, S60C, S65C, S70C, and S75C, as specified in JIS G 4051:2016.

[0020] Low alloy steel refers to carbon steel containing at least one of Al, B, Co, Cr, Cu, La, Mo, Nb, Ni, Pb, Se, Te, Ti, V, W, and Zr, with the total content of these elements being 5 mass% or less.

[0021] Tool steel refers to carbon tool steel materials specified in JIS G 4401:2009 and alloy tool steel materials specified in JIS G 4404:2006.

[0022] Stainless steel is an alloy of Fe and Cr, containing 10.5 mass% or more of Cr and 1.2 mass% or less of C. Other components are specified, for example, in ISO 15510:2014. Examples of stainless steel include SUS304, SUS304L, SUS304ULC, SUS310ULC, and SUSXM15J1.

[0023] The conductive member 2 has a columnar shape, and is not limited to any particular shape as long as it can be inserted into the inner periphery of the insulating member 1. The conductive member 2 may have, for example, a cylindrical shape or a prismatic shape (e.g., a triangular prism, a square prism, a pentagonal prism, a hexagonal prism, etc.). For example, if the insulating member 1 is cylindrical, the conductive member 2 has a columnar shape, and if the insulating member 1 is square-tube, the conductive member 2 has a square-prism shape.

[0024] The size of the conductive member 2 is not limited as long as it can be inserted into the inner peripheral side of the insulating member 1. Specifically, the length (axial length) of the conductive member 2 is shorter than the length (axial length) of the insulating member 1, and the outer diameter of the outermost periphery of the conductive member 2 is set appropriately depending on the inner diameter of the insulating member 1.

[0025] 2, the flanged annular member 3 has an annular base 31 and a flange 32 extending radially from the base 31. The flanged annular member 3 is formed, for example, by integrally molding the base 31 and the flange 32 from a metal or the like. Similar to the conductive member 2, examples of metals that can be used to form the flanged annular member 3 include carbon steel, low-alloy steel, tool steel, stainless steel, iron, copper, copper alloys, titanium, titanium alloys, molybdenum, molybdenum alloys, Fe-Ni alloys, Fe-Ni-Cr-Ti-Al alloys, Fe-Cr-Al alloys, Fe-Co-Cr alloys, Fe-Co-based alloys, Fe-Co-C-based alloys, Fe-Ni-based alloys, and Fe-Ni-Co-based alloys.

[0026] The flanged annular member 3 is joined to the outer peripheral surface of the conductive member 2 and to a first step surface 11a that forms the first step portion 11 of the insulating member 1. The size of the flanged annular member 3 is not limited as long as it is large enough to be joined to the outer peripheral surface of the conductive member 2 and to the first step surface 11a that forms the first step portion 11 of the insulating member 1, depending on the sizes of the insulating member 1 and the conductive member 2.

[0027] When the bonding agent for bonding the flanged annular member 3 to the outer peripheral surface of the conductive member 2 and the first stepped surface 11a is a brazing filler metal, the brazing filler metal is, for example, a silver brazing filler metal such as BAg-8, BAg-8A, BAg-8B, or BAg-9, or an Ag-Cu-Ti-based active brazing filler metal. When using a silver brazing filler metal, it is preferable to first form a Mo-Mn layer and a nickel plating layer in this order on the first stepped surface 11a from the first stepped surface 11a side, and then bond the two surfaces with the brazing filler metal via these layers.

[0028] As described above, the hermetic terminal 10 according to one embodiment includes the insulating member 1, the conductive member 2, and the flanged annular member 3. Therefore, the hermetic terminal 10 according to one embodiment is less likely to develop cracks in the insulating member even when used repeatedly in high-temperature and low-temperature environments. Furthermore, the hermetic terminal 10 according to one embodiment does not use a resin insulating tube such as a polytetrafluoroethylene tube, and therefore is less likely to generate particles.

[0029] As shown in Fig. 2, the flanged annular member 3 may be joined to the first inner circumferential surface 11b that forms the first step portion 11 of the insulating member 1. This configuration increases the joining surface area between the flanged annular member 3 and the insulating member 1. As a result, the joining strength between the insulating member 1 and the flanged annular member 3 can be improved. Furthermore, the airtightness of the resulting hermetic terminal 10 can be further improved.

[0030] When the joining agent for joining the flanged annular member 3 to the first inner circumferential surface 11b is a brazing filler metal, this brazing filler metal is, for example, a silver brazing filler metal such as BAg-8, BAg-8A, BAg-8B, or BAg-9, an Ag-Cu-Ti based active brazing filler metal, etc. When a silver brazing filler metal is used, it is preferable to first form a Mo-Mn layer and a nickel plating layer in this order on the first inner circumferential surface 11b side, and then join the first inner circumferential surface 11b with the brazing filler metal interposed therebetween.

[0031] As shown in FIG. 2 , the conductive member 2 may have a second step 21 on the outer periphery of the end face of the insulating member 1, which faces the first step 11. The flanged annular member 3 may be joined to the outer periphery 21b of the insulating member 1, forming the second step 21. This configuration improves positioning accuracy and allows the conductive member 2 to be stably installed. Furthermore, since the joining position can be closer to the axial center of the insulating member 1, centrifugal force acting on a bonding agent such as a brazing material can be reduced, even when used in an environment where vibrations are applied in the radial direction, and bonding strength can be maintained over a long period of time. When the bonding agent joining the flanged annular member 3 to the outer periphery 21b is a brazing material, the brazing material may be, for example, a silver brazing material such as BAg-8, BAg-8A, BAg-8B, or BAg-9, or an Ag-Cu-Ti-based active brazing material.

[0032] 1, the conductive member 2 may be provided with a recess 5 at least on the side where the first step portion 11 is provided. By providing such a recess 5, a member that can be electrically connected to the conductive member 2 can be attached inside the recess 5. Furthermore, it is possible to reduce the detachment of the attached member.

[0033] As shown in FIG. 2, the flanged annular member 3 may be joined to the second step surface 21a that forms the second step portion 21 of the conductive member 2. This configuration increases the joining area between the flanged annular member 3 and the conductive member 2. As a result, the joining strength between the conductive member 2 and the flanged annular member 3 can be improved. Furthermore, the airtightness of the resulting hermetic terminal 10 can also be further improved. When the joining agent that joins the flanged annular member 3 to the second step surface 21a is a brazing material, examples of the brazing material include silver brazing materials such as BAg-8, BAg-8A, BAg-8B, and BAg-9, and Ag-Cu-Ti-based active brazing materials.

[0034] In the airtight terminal 10 according to one embodiment, the average linear expansion coefficients of the insulating member 1, the conductive member 2, and the flanged annular member 3 are not particularly limited. The average linear expansion coefficient of the insulating member 1 is, for example, 2.4×10 -6 / K or more 7.5×10 -6 / K or less. The average linear expansion coefficient of the conductive member 2 may be, for example, 4.6×10 -6 / K or more 17.7×10 -6 / K or less. The average linear expansion coefficient of the flanged annular member 3 may be, for example, 4.6×10 -6 / K or more 17.7×10 -6 In the airtight terminal of this embodiment, the average linear expansion coefficient of the conductive member 2 may be greater than the average linear expansion coefficient of the insulating member 1, and the difference between them may be 10×10 -6 This is effective when the value is / K or higher.

[0035] The average linear expansion coefficient of the insulating member 1 may be determined in accordance with JIS R 1618:2002. The average linear expansion coefficients of the conductive member 2 and the flanged annular member 3 may be determined in accordance with JIS Z 2285:2003. However, if the size of each of the above members is small and it is not possible to cut a sample from each member into the size specified by the JIS standard, a sample cut as large as possible may be used as the sample for measuring the average linear expansion coefficient. The temperature range for measuring the average linear expansion coefficient for each member is 40°C or higher and 400°C or lower.

[0036] For example, the average linear expansion coefficient of the flanged annular member 3 may be between the average linear expansion coefficient of the insulating member 1 and the average linear expansion coefficient of the conductive member 2. When the average linear expansion coefficients of the members satisfy this relationship, stress is less likely to accumulate in the members. As a result, the hermetic terminal 10 having this configuration can be used for a long period of time even when repeatedly used in high-temperature and low-temperature environments.

[0037] As described above, the flanged annular member 3 has an annular base 31 and a flange 32 extending radially from the base 31. As shown in FIG. 2, the outer peripheral surface of the base 31 and the annular surface of the flange 32 located on the base 31 side may be connected via a curved surface. With this configuration, stress accumulated in the flanged annular member 3 is reduced even when used repeatedly in high and low temperature environments, compared to when the outer peripheral surface of the base 31 and the annular surface of the flange 32 located on the base 31 side are perpendicular to each other. As a result, the hermetic terminal 10 having this configuration can be used for a long period of time.

[0038] The curvature of this curved surface is not limited and may be, for example, 1.25 (1 / mm) or more and 5 (1 / mm) or less. To determine the curvature, first, a scanning electron microscope is used to photograph the entire cross section of the flanged annular member 3, including its axis. The curvature of the curved surface can be determined by tracing the curved surface between the outer peripheral surface of the base 31 and the annular surface of the flange 32 located on the base 31 side, which is displayed in the photographed image.

[0039] As shown in FIGS. 1 and 2 , in an airtight terminal 10 according to one embodiment, an annular gap 4 may be present between the outer circumferential surface of the base 31 and the inner circumferential surface of the insulating member 1 facing the outer circumferential surface. The presence of such an annular gap 4 allows a fillet of a bonding agent, such as a brazing material, to be formed within the gap 4, bonding the insulating member 1 to the flanged annular member 3. This increases the bonding area between the insulating member 1 and the flanged annular member 3, thereby increasing the bonding strength between them. Furthermore, even if the conductive member 1 has a high average linear expansion coefficient, the expansion can be absorbed by the gap 4. This reduces the likelihood of cracks occurring in the insulating member 1.

[0040] 2, the insulating member 1 may have a third step surface 41a that extends from the second inner circumferential surface 11c of the insulating member 1 toward the axis of the insulating member 1 and seals one end of the annular gap 4. By having the third step surface 41a, the volume of the gap 4 can be increased compared to when the third step surface 41a is not present. As a result, the amount of fillet of the bonding agent can be increased, and the reliability of the bonding between the insulating member 1 and the flanged annular member 3 can be improved.

[0041] At least one of the second inner circumferential surface 11c and the third step surface 41a of the insulating member 1 may be a fired surface. If at least one of the second inner circumferential surface 11c and the third step surface 41a of the insulating member 1 is a fired surface, no crushed layer is present on the second inner circumferential surface 11c and the third step surface 41a of the insulating member 1. As a result, even if gas flows along the second inner circumferential surface 11c and the third step surface 41a of the insulating member 1, the risk of particles being detached is reduced.

[0042] In the airtight terminal 10 according to one embodiment, the outer peripheral surface of the end of the conductive member 2 opposite to the side where the flanged annular member 3 is joined with respect to the axial center of the insulating member 1 may be in contact with the insulating member 1 without being joined. With this configuration, residual stress occurring in the insulating member 1 on the side where it is joined with the conductive member 2 can be released. As a result, cracks are less likely to occur in the insulating member 1.

[0043] The hermetic terminal 10 according to one embodiment can be used in various devices, such as cooling devices, plasma processing devices, electric vehicles, and hybrid vehicles.

[0044] The hermetic terminal according to the present disclosure is not limited to the hermetic terminal 10 described above. For example, in the hermetic terminal according to the present disclosure, a metallized layer may be formed on the first step portion and the first step surface provided on the insulating member. In the hermetic terminal 10 according to the above-described embodiment, a metallized layer is not formed on the first step portion 11 and the first step surface 11a provided on the insulating member 1. However, by forming such a metallized layer, it is possible to improve the bonding strength between, for example, an insulating member made of ceramic and a flanged annular member made of metal. [Explanation of symbols]

[0045] 1. Insulating material 11 First step 11a 1st step surface 11b 1st inner peripheral surface 11c 2nd inner surface 2 Conductive material 21 Second step 21a 2nd step surface 21b outer peripheral surface forming the second step portion 3. Annular member with flange 31 Base 32 Tsuba 4 Annular gap 41a 3rd step surface 5 recess 10 Airtight terminal

Claims

1. a cylindrical insulating member having a first step portion on an inner circumferential side of one end surface; a columnar conductive member inserted into the inner circumferential side of the insulating member and having an axial length shorter than that of the insulating member; a flanged annular member joined to an outer peripheral surface of the conductive member and a first step surface that forms the first step portion, Airtight terminal.

2. The hermetic terminal according to claim 1 , wherein the flanged annular member is joined to a first inner circumferential surface that forms the first step portion.

3. 3. The airtight terminal according to claim 1, wherein the conductive member has a second step portion on the outer circumferential side of the end face on the side of the first step portion, and the flanged annular member is joined to the outer circumferential surface that forms the second step portion.

4. The hermetic terminal according to claim 3 , wherein the flanged annular member is joined to a second stepped surface that forms the second stepped portion.

5. The hermetic terminal according to any one of claims 1 to 4, wherein the conductive member has a recess at least on the side where the first step portion is provided.

6. 6. The airtight terminal according to claim 1, wherein the average linear expansion coefficient of the flanged annular member is between the average linear expansion coefficient of the insulating member and the average linear expansion coefficient of the conductive member.

7. The hermetic terminal according to any one of claims 1 to 6, wherein the flanged annular member has an annular base and a flange extending radially from the base, and the outer peripheral surface of the base and the annular surface located on the base side of the flange are connected via a curved surface.

8. The hermetic terminal according to claim 7 , wherein an annular gap is interposed between an outer circumferential surface of the base and a second inner circumferential surface of the insulating member that faces the outer circumferential surface of the base.

9. 9. The airtight terminal according to claim 8, wherein the insulating member has a third stepped surface that extends from the second inner peripheral surface of the insulating member toward an axial center of the insulating member and seals one end of the annular gap portion.

10. The hermetic terminal according to claim 9 , wherein at least one of the second inner peripheral surface and the third stepped surface of the insulating member is a fired surface.

11. The airtight terminal according to any one of claims 1 to 10, wherein the outer surface of the end of the conductive member opposite to the side to which the flanged annular member is joined relative to the center of the axial direction is in contact with the insulating member without being joined.

12. A cooling device comprising the hermetic terminal according to any one of claims 1 to 11.

13. A plasma processing apparatus comprising the hermetic terminal according to any one of claims 1 to 11.

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