cooler

Abstract

To prevent the formation of intermetallic compounds in a cooler that uses metallic components made of different materials.SOLUTION: In a semiconductor device 1, a cooler 2 includes a heat dissipation portion 30 having a flat base portion 31 to which heat generated by an IC chip 53, which is a heat-generating element, is transferred, and a fin portion 32 protruding from the base portion in a direction intersecting the plate surface of the base portion, a lid portion 20 arranged around the heat dissipation portion 30, and a connecting portion 40 formed by stacking a first layer 41 molded from the same material as the heat dissipation portion 30 and a second layer 42 molded from the same material as the lid portion 20, and the first layer 41 of the connecting portion 40 and the heat dissipation portion 30 are joined by welding, and the second layer 42 of the connecting portion 40 and the lid portion 20 are joined by welding.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cooler. [Background technology]

[0002] The cooler described in Patent Document 1 includes a box-shaped container body having an opening on its top surface, and a base plate having a number of heat dissipation fins formed on the underside of its inner periphery and on the upper surface of the inner periphery, on which a heat generating element can be placed. With the heat dissipation fins housed within the container body through its top opening, the outer periphery of the base plate is fixed to the periphery of the top opening of the container body via a sealing member, thereby assembling the base plate to the container body so as to close the top opening. This cooler is characterized in that the base plate is formed by having an inner periphery and an outer periphery formed separately and then integrally connected, and the inner periphery of the base plate is formed from a material with a higher thermal conductivity than the outer periphery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7126423 Summary of the Invention [Problem to be solved by the invention]

[0004] The material of the metal member used in the heat dissipation section of a cooler may be different from the material of the metal member used around the heat dissipation section. In this case, when these different metal members are welded together, an intermetallic compound consisting of two or more metals is formed. This intermetallic compound is generally more brittle than when the same type of metal is welded together. Therefore, a cooler in which metal members made of different materials are welded together may have lower strength and may experience reduced sealing performance.

[0005] An object of the present invention is to suppress the formation of intermetallic compounds in a cooler in which metal members made of different materials are used. [Means for solving the problem]

[0006] A cooler to which the present invention is applicable comprises a first member having a flat base portion to which heat generated by a heat-generating element is transferred and a fin portion protruding from the base portion in a direction intersecting the plate surface of the base portion; a second member arranged around the first member; and a laminated member in which a first layer molded from the same material as the first member and a second layer molded from the same material as the second member are laminated together, wherein the first layer of the laminated member and the first member are joined by welding, and the second layer of the laminated member and the second member are joined by welding. Here, the material used for the first member may be characterized in that its thermal conductivity is higher than that of the material used for the second member. Furthermore, the material of the first member is copper and the material of the second member is aluminum, and the materials of the laminated member can be characterized in that the first layer is copper and the second layer is aluminum. The thickness of the second layer in the stacking direction may be greater than the thickness of the first layer in the stacking direction. The first layer of the laminated member and the first member are laser welded, and the second layer of the laminated member and the second member are laser welded. It can also be characterized in that the position where the first member and the first layer are welded and the position where the second member and the second layer are welded do not overlap in a direction intersecting the direction in which the first layer and the second layer of the laminated member are stacked. The first layer of the laminated member may be disposed in contact with the plate surface of the base portion of the first member from which the fin portion projects. The position where the second member and the second layer are welded may be located closer to the fin portion than the position where the first member and the first layer are welded. The laminated member may be characterized in that it has an annular shape. The laminated member can also be characterized in that it is formed into a ring shape by curving or bending a rod-shaped member formed by laminating the first layer and the second layer into a rod shape. The second member may be provided with a recess at a position facing the outer peripheral edge of the first member, and the stacked member may be disposed in the recess. The laminated member may be a clad material in which the first layer and the second layer are roll-bonded. [Effects of the Invention]

[0007] According to the present invention, it is possible to suppress the generation of intermetallic compounds in a cooler in which metal members made of different materials are used. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is an example of an exploded view of components constituting the semiconductor device according to the embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of a cross section of a cooler according to an embodiment. [Figure 3] 10A to 10C are diagrams illustrating an example of a manufacturing method for a connecting portion. [Figure 4] 3 is a diagram showing an example of a cross section of a cooler, and is an enlarged view of region IV in FIG. 2. FIG. [Figure 5] FIG. 10 is a diagram illustrating an example of a state in which laser light is irradiated. [Figure 6] 1(a) and 1(b) are diagrams showing an example of a welding path. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is an example of an exploded view of components constituting a semiconductor device 1 according to an embodiment. Fig. 2 is a diagram showing an example of a cross section of the cooler 2 according to the embodiment. Fig. 2 is an example of a cross section of the cooler 2 cut along a plane perpendicular to the front-rear direction. Note that Fig. 2 shows the cross section of the cooler 2, and does not show the semiconductor module 5. The semiconductor device 1 includes one or more (three in FIG. 1) semiconductor modules 5 and a cooler 2 that cools the semiconductor modules 5.

[0010] [Semiconductor Module 5] The semiconductor module 5 has an insulating substrate 51, a wiring layer 52 provided on the insulating substrate 51, and an IC chip 53 (an example of a heat generating element) attached to the wiring layer 52 via a solder layer 54. The semiconductor module 5 also has a heat transfer layer 55 that transfers heat from the insulating substrate 51 to the heat dissipation section 30. The heat transfer layer 55 is bonded to an upper surface of a base section 31 (described later) of the heat dissipation section 30. Examples of methods for bonding the heat transfer layer 55 to the heat dissipation section 30 include brazing, soldering, sintering, bonding with resin, and pasting with thermally conductive grease. The multiple semiconductor modules 5 are arranged in the left-right direction.

[0011] [Cooler 2] The cooler 2 is a liquid-cooling type cooler that cools the semiconductor module 5 using a coolant. The cooler 2 includes a concave jacket 10 with a bottom that forms a space through which the coolant flows, a lid 20 that covers the opening of the jacket 10, and a heat dissipation unit 30 that has the semiconductor module 5 attached thereto and dissipates heat generated from the IC chip 53 of the semiconductor module 5. The cooler 2 further includes a connecting unit 40 that connects the lid 20 and the heat dissipation unit 30. The heat dissipation unit 30 is an example of a first member, and the lid 20 is an example of a second member. The connecting unit 40 is an example of a stacked member.

[0012] The jacket 10 and the lid 20 are laminated together. The material of the jacket 10 can be, for example, aluminum. The material of the lid portion 20 can be, for example, aluminum. The heat dissipation portion 30 can be, for example, made of a material having a higher thermal conductivity than the lid portion 20. More specifically, the material of the heat dissipation portion 30 can be, for example, copper. The material of the lid 20 may be, for example, iron or stainless steel. In this case, the material of the heat dissipation part 30 may be, for example, aluminum or copper.

[0013] [Jacket 10] The jacket 10 includes bolts 11 that secure the jacket 10 to the lid 20, and an O-ring 12 that seals the gap between the jacket 10 and the lid 20. The jacket 10 also includes an inlet pipe 14 that introduces the coolant into the jacket 10, and an outlet pipe 15 that discharges the coolant from inside the jacket 10.

[0014] Hereinafter, the stacking direction of the jacket 10 and the lid 20 may be referred to as the "vertical direction," the lid 20 side may be referred to as the "upper side," and the jacket 10 side may be referred to as the "lower side." Furthermore, the direction perpendicular to the vertical direction, from the inlet pipe 14 to the outlet pipe 15, may be referred to as the "left-right direction." Furthermore, the direction perpendicular to the vertical and left-right directions may be referred to as the "front-rear direction." Furthermore, when it is not necessary to distinguish between the left-right direction and the front-rear direction, the left-right direction and the front-rear direction may be collectively referred to as the "horizontal direction."

[0015] [Lid part 20] The lid portion 20 is a plate-shaped member. The thickness of the lid portion 20 is shown as D1 in Fig. 2. Of the plate surfaces of the lid portion 20, the upper surface in the vertical direction is referred to as the upper surface 28, and the lower surface is referred to as the lower surface 29. The lid portion 20 is formed with a plurality of recesses 21 (three in Fig. 1) for disposing the heat dissipation portion 30. The lid portion 20 is formed with bolt holes 27 that pass through to pass the bolts 11.

[0016] The recess 21 is recessed downward from the upper surface 28. The recess 21 has a bottom 22 that forms the bottom of the recess 21, and a side surface 23 that extends upward from the edge of the bottom 22 and connects to the upper surface 28. The bottom 22 has through holes 24 formed therein, through which fins 33 (described later) of the heat dissipation unit 30 pass. The thickness of the bottom 22 is shown as D2 in FIG. 2. In the region of the recess 21, the thickness of the bottom 22 is D2, which is smaller than the thickness D1 of the lid 20. When the heat dissipation unit 30 is disposed in the recess 21, the smaller the thickness of the bottom 22, the longer the length by which the fins 33 protruding from the through holes 24 protrude downward in the vertical direction from the lower surface 29, thereby improving the heat dissipation effect.

[0017] The bottom 22 has a rectangular shape when viewed from above and below, and a rectangular through-hole 24 is formed in the center of the bottom 22. However, the shapes of the through-hole 24 and the bottom 22 are not limited to these. For example, the shapes of the through-hole 24 and the bottom 22 can be circular.

[0018] [Heat dissipation part 30] The heat dissipation section 30 includes a flat base section 31 to which heat generated by the semiconductor module 5 is transferred, and fin sections 32 that protrude from the base section 31 in a direction intersecting the plate surface of the base section 31. The base section 31 and the fin sections 32 are integrally molded.

[0019] The fin portion 32 has a plurality of columnar fins 33 that protrude vertically from the base portion 31. The fin portion 32 is provided in a region extending inward from the outer edge of the base portion 31 by a predetermined length. This region extending inward from the outer edge by a predetermined length is called the protruding region 35. This protruding region 35 has substantially the same shape as the through holes 24, allowing the plurality of fins 33 to pass through the through holes 24. In the base portion 31, the region outside the protruding region 35 is called the flat region 36. When the heat dissipation portion 30 is viewed vertically from below, the flat region 36 surrounds the protruding region 35. The flat region 36 is an example of an outer peripheral edge.

[0020] The cross-sectional shape of the fins 33 on a plane perpendicular to the protruding direction of the fins 33 can be, for example, a circle, an ellipse, a square, a rectangle, a diamond, or other quadrangle. The fins 33 may also be flat. If the fins 33 are flat, they may be parallel to the left-right direction (in other words, the direction from the inlet pipe 14 to the outlet pipe 15), or may be wavy with portions inclined in the left-right direction. Furthermore, the fins 33 may be plated, for example, to improve corrosion resistance. An example of the plating performed on the fins 33 is nickel plating.

[0021] [Connection part 40] The connecting portion 40 is an annular member. The connecting portion 40 is molded to fit into the recess 21. When viewed from above in the vertical direction, the connecting portion 40 has substantially the same shape as the bottom 22 of the recess 21. By fitting the connecting portion 40 into the recess 21, alignment can be easily performed.

[0022] The connecting portion 40 forms a ring that is closed in the horizontal direction, and includes a first layer 41 and a second layer 42 that are stacked in the vertical direction. The first layer 41 is located above the second layer 42. The material of the second layer 42 is a material suitable for welding to the lid portion 20. For example, the same metal material as that of the lid portion 20 is used. More specifically, when the material of the lid portion 20 is aluminum, the material of the second layer 42 is aluminum. Furthermore, a material suitable for welding to the heat dissipation section 30 is used for the first layer 41. For example, the same metal material as that of the heat dissipation section 30 is used. More specifically, when the material of the heat dissipation section 30 is copper, the material of the first layer 41 is copper. The connecting portion 40 may be, for example, a clad material. The first layer 41 and the second layer 42 may be joined by roll-joining the first layer 41 and the second layer 42, for example.

[0023] [Method for manufacturing the connecting portion 40] FIG. 3 is a diagram showing an example of a method for manufacturing the connecting portion 40 (see FIG. 1). Here, we will explain an example of manufacturing a connecting portion 40 using a plate-shaped clad material 400 in which a plate-shaped first plate-shaped member 410 formed from the material of the first layer 41 (see Figure 1) and a plate-shaped second plate-shaped member 420 formed from the material of the second layer 42 (see Figure 1) are stacked in the thickness direction of the plate. An example of this plate-shaped clad material 400 is one in which a first plate-shaped member 410 and a second plate-shaped member 420 are rolled and joined together. In FIG. 3, the description will be given assuming that the first plate-shaped member 410 is disposed on the upper side in the stacking direction shown in FIG. 3, and the second plate-shaped member 420 is disposed on the lower side in the stacking direction. First, the plate-shaped clad material 400 is cut in the stacking direction at the positions indicated by the dashed lines in Fig. 3 to form rod-shaped clad materials 401. Here, rod-shaped refers to a rod whose cross section perpendicular to the direction in which the rod extends is rectangular.

[0024] In Figure 3, one end of rod-shaped clad material 401 in the direction in which the rod extends is shown as end 401a, and the other end is shown as end 401b. Rod-shaped clad material 401 is bent into a ring shape in a plane perpendicular to the lamination direction so that end 401a and end 401b come into contact with each other. This forms connecting portion 40 shown in Figure 1.

[0025] Furthermore, when bending rod-shaped clad material 401, a notch may be provided in the portion to be bent. This notch prevents the excess portion from expanding in the vertical direction when bent. Furthermore, if the shape of connecting portion 40 when viewed from the top and bottom is a circular or elliptical ring, connecting portion 40 may be manufactured by bending a rod-shaped clad material.

[0026] Another example of a method for manufacturing the connecting portion 40 is to hollow out a plate-shaped clad material 400 that has been rolled into a flat shape, to manufacture the connecting portion 40. In this case, the clad material in the hollowed-out portion is discarded, and therefore the material yield tends to be lower than when manufacturing the connecting portion 40 by bending a rod-shaped clad material 401.

[0027] [Connection between the lid portion 20 and the heat dissipation portion 30] As described above, in this embodiment, the lid part 20 and the heat dissipation part 30 are connected via the connecting part 40. Here, a method for connecting the lid part 20 and the heat dissipation part 30 via the connecting part 40 will be described in more detail. FIG. 4 is a diagram showing an example of a cross section of the cooler 2, and is an enlarged view of region IV in FIG. FIG. 5 is a diagram showing an example of a state in which the laser light L is irradiated. Figures 6(a) and (b) are diagrams showing an example of a welding path. Figure 6(a) is a diagram showing the lid portion 20, the heat dissipation portion 30, and the connecting portion 40 viewed from above in the vertical direction. Figure 6(b) is a diagram showing the lid portion 20 and the heat dissipation portion 30 viewed from below in the vertical direction.

[0028] First, the welding of the heat dissipation portion 30 and the connecting portion 40 will be described. As shown in FIG. 4, the base portion 31 includes a base portion main body 31a and a welding flange 31b on the outer periphery of the base portion main body 31a. The welding flange 31b has a predetermined thickness and protrudes horizontally from the base portion main body 31a in order to perform welding with the first layer 41 that comes into contact with the welding flange 31b. This predetermined thickness is designed as the thickness required for welding. For example, when welding is performed using a laser beam, if the vertical thickness of the welding flange 31b is too large, a molten pool may not be formed up to the first layer 41 during laser welding. Also, for example, if the vertical thickness of the welding flange 31b is too large, the molten pool may spread too much horizontally to reach the first layer 41. Also, for example, if the vertical thickness of the welding flange 31b is too large, more energy will be consumed to irradiate the laser beam L. On the other hand, if the vertical thickness of the welding flange 31b is too thin, the molten pool may become larger than necessary and may reach the second layer 42.

[0029] Welding flange 31b covers the outer periphery of base body 31a when viewed from above and below. Welding flange 31b and base body 31a are formed so that the surfaces on the side where fins 33 protrude are continuous without any steps. As shown in Fig. 5, laser head 151, which is positioned above welding flange 31b, irradiates welding flange 31b with laser light L in the vertical direction. Laser light L melts welding flange 31b, and also melts first layer 41 in contact with the molten welding flange 31b. As a result, a first welded zone Y1 (see Fig. 4) is formed between welding flange 31b and first layer 41. As this molten first welded zone Y1 solidifies, welding flange 31b and first layer 41 are welded together.

[0030] The position where the laser light is irradiated is shown by the thick line in Fig. 6(a), and the laser head 151 (see Fig. 5) moves while irradiating the position shown by the thick line in Fig. 6(a) with the laser light L. In this way, the irradiation target of the laser light L moves along the welding flange 31b, and the entire circumference of the base portion main body 31a is welded.

[0031] Next, the welding of the cover portion 20 and the connecting portion 40 will be described. As shown in Fig. 4, a recess 25 recessed upward is provided on the underside 29 of the lid 20 around the through-hole 24 (see Fig. 1). This recess 25 is provided at a position where laser welding will be performed. The area where recess 25 is provided is formed to a predetermined thickness that allows welding to be performed, and the thickness of the bottom 22 is thinner than other areas.

[0032] As shown in Fig. 5, laser light L is irradiated onto recess 25 in the vertical direction from laser head 151 disposed below recess 25. This laser light L melts recess 25, and further melts second layer 42 in contact with the melted recess 25, forming second welded zone Y2 (see Fig. 4). This liquid second welded zone Y2 becomes solid, thereby welding recess 25 and second layer 42 together.

[0033] The position where the laser light is irradiated is shown by the thick line in Fig. 6(b), and the laser head 151 moves while irradiating the position shown by the thick line in Fig. 6(b) with the laser light L. In this way, the irradiation destination of the laser light L moves along the recessed portion 25, and the recessed portion 25 around the through hole 24 (see Fig. 1) is welded all around.

[0034] 5, there are two directions in which the laser light L is irradiated: from top to bottom in the vertical direction, and from bottom to top in the vertical direction. However, for example, after forming the first welded portion Y1, the lid portion 20, the heat dissipation portion 30, and the connecting portion 40 may be turned over while still assembled, and the laser light L may be irradiated onto the recessed portion 25 of the lid portion 20 while still directed from top to bottom. This allows the direction in which the laser light L is irradiated to be consistent, and welding can be performed without changing the orientation of the laser head 151.

[0035] The first welded zone Y1 thus formed is formed by melting the heat dissipation portion 30 and the first layer 41. In this embodiment, the heat dissipation portion 30 and the first layer 41 are both made of copper, for example. Because the heat dissipation portion 30 and the first layer 41 are made of the same material, no intermetallic compound is formed in the first welded zone Y1. The second welded zone Y2 is formed by melting the lid portion 20 and the second layer 42. In this embodiment, the lid portion 20 and the second layer 42 are both made of aluminum, for example. Because the lid portion 20 and the second layer 42 are made of the same material, no intermetallic compound is formed in the second welded zone Y2.

[0036] Furthermore, in this embodiment, the positional relationship between the weld flange 31b and the recessed portion 25 is such that the recessed portion 25 is provided inside the weld flange 31b when viewed in the vertical direction. As a result, the position of the second welded portion Y2 that welds the cover portion 20 to the second layer 42 and the position of the first welded portion Y1 that welds the heat dissipation portion 30 to the first layer 41 do not overlap in a direction intersecting the direction in which the second layer 42 and the first layer 41 of the connecting portion 40 are stacked. This prevents the first welded portion Y1 and the second welded portion Y2 from being integrated together.

[0037] When viewed from the top and bottom, recess 25, where lid 20 and second layer 42 are welded, is located closer to fin 32 than weld flange 31b, where heat dissipation section 30 and first layer 41 are welded. This allows O-ring 12, which seals between jacket 10 and lid 20, to be closer to fin 33, making it possible to reduce the size of the jacket. When viewed from the top and bottom, the position of the recess 25 where the lid portion 20 and the second layer 42 are welded may be located closer to the side surface 23 than the position of the welding flange 31b where the heat dissipation portion 30 and the first layer 41 are welded. This increases the distance between the position where the laser light L is irradiated and the fin 33, making it easier to irradiate the laser light L.

[0038] Here, an example is shown in which the first weld Y1 between the heat dissipation portion 30 and the first layer 41 is formed, and then the second weld Y2 between the lid portion 20 and the second layer 42 is formed. However, the order in which the first weld Y1 and the second weld Y2 are formed is not particularly limited. For example, the first weld Y1 may be formed after the second weld Y2 is formed.

[0039] The first layer 41 of the connecting part 40 is arranged in contact with the flat region 36, which is the plate surface on the side where the fin part 32 protrudes in the base part 31 of the heat dissipation part 30. The protruding fins 33 are arranged to pass through the inner periphery of the ring of the annular connecting part 40, thereby aligning the connecting part 40 and the heat dissipation part 30.

[0040] In this embodiment, a cooler 2 is shown that includes a heat dissipation unit 30 having a flat base 31 to which heat generated by an IC chip 53 is transferred, a fin 32 protruding from the base 31 in a direction intersecting the plate surface of the base 31, a lid 20 disposed around the heat dissipation unit 30, and a connecting unit 40 including a first layer 41 formed of the same material as the heat dissipation unit 30 and a second layer 42 formed of the same material as the lid 20, the first layer 41 of the connecting unit 40 being joined to the heat dissipation unit 30 by welding, and the second layer 42 of the connecting unit 40 being joined to the lid 20 by welding. As described above, because the heat dissipation unit 30 and the first layer 41 are made of the same material, no intermetallic compounds are generated when the heat dissipation unit 30 and the connecting unit 40 are welded together. Furthermore, because the lid 20 and the second layer 42 are made of the same material, no intermetallic compounds are generated when the lid 20 and the second layer 42 are welded together. This suppresses the generation of intermetallic compounds, which are generally brittle, compared to when metal members made of different materials are welded together. Therefore, the cooler 2 of this embodiment has higher strength and sealing performance than when, for example, the heat dissipation part 30 made of copper and the lid part 20 made of aluminum are welded together.

[0041] The cooler 2 of this embodiment is a liquid-cooled cooler. However, for example, the lid portion 20 and the heat dissipation portion 30 connected via the connecting portion 40 may be used as an air-cooled cooler.

[0042] Furthermore, the thicknesses of the first layer 41 and the second layer 42 of the connecting portion 40 are not particularly limited. The first layer 41 and the second layer 42 may have the same thickness, or the thicknesses of the first layer 41 and the second layer 42 may be different. For example, the thicknesses of the first layer 41 and the second layer 42 may be determined depending on the depth of at least one of the first weld Y1 and the second weld Y2 formed by laser irradiation. For example, the thickness of a member in which a deeper weld is more likely to be formed by laser irradiation may be increased. This can suppress the formation of an intermetallic compound between the first layer 41 and the second layer 42.

[0043] The thickness of the first layer 41 and the thickness of the second layer 42 may also be selected by comparing the cost of the materials for the first layer 41 and the second layer 42. For example, if the material for the first layer 41 is copper and the material for the second layer 42 is aluminum, the thickness of the first layer 41, which uses copper, which has a higher unit price, can be reduced to reduce costs. [Explanation of symbols]

[0044] 1...semiconductor device, 2...cooler, 5...semiconductor module, 10...jacket, 20...lid portion, 21...recess, 22...bottom, 23...side, 24...through hole, 25...dent portion, 27...bolt hole, 30...heat dissipation portion, 31...base portion, 31a...base portion main body, 31b...welding flange, 32...fin portion, 33...fin, 35...protruding region, 36...flat region, 40...connecting portion, 41...first layer, 42...second layer

Claims

1. a first member having a flat base portion to which heat generated by a heat generating element is transferred and a fin portion protruding from the base portion in a direction intersecting with the plate surface of the base portion; a second member disposed around the first member; a laminated member in which a first layer formed of the same material as the first member and a second layer formed of the same material as the second member are laminated; Equipped with The first layer of the laminated member and the first member are joined by welding, and the second layer of the laminated member and the second member are joined by welding. cooler.

2. The material used for the first member has a higher thermal conductivity than the material used for the second member. The cooler of claim 1 .

3. The material of the first member is copper. the second member is made of aluminum; The first layer of the laminated member is made of copper, and the second layer is made of aluminum. The cooler of claim 2 .

4. The thickness of the second layer in the stacking direction is greater than the thickness of the first layer in the stacking direction. The cooler of claim 3 .

5. The first layer of the laminated member and the first member are laser welded, and the second layer of the laminated member and the second member are laser welded. The cooler of claim 1 .

6. A position where the first member and the first layer are welded and a position where the second member and the second layer are welded do not overlap in a direction intersecting a direction in which the first layer and the second layer of the laminated member are stacked. The cooler according to claim 5 .

7. The first layer of the laminated member is disposed in contact with a plate surface of the base portion of the first member from which the fin portion protrudes. The cooler of claim 6.

8. The position where the second member and the second layer are welded is located closer to the fin portion than the position where the first member and the first layer are welded. The cooler of claim 6.

9. The laminated member has a ring shape. The cooler of claim 1 .

10. The laminated member is formed into a ring shape by bending or bending a rod-shaped member formed by laminating the first layer and the second layer. The cooler of claim 9.

11. the second member has a recess provided at a position facing the outer peripheral edge of the first member; The laminated member is disposed in the recess. The cooler of claim 7.

12. The laminated member is a clad material in which the first layer and the second layer are roll-bonded. The cooler of claim 1 .

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