Heat sink, and manufacturing method thereof

Abstract

To provide a heat sink, etc. that can suppress the peeling of two members made of different materials.SOLUTION: A heat sink that has a flat plate-shaped base portion and a plurality of fins protruding from the plate surface of the base portion, and also has two members made of different materials, and a first member which is a member of the two members arranged on the opposite side to the fin includes a first base that has a flat plate shape and a flat surface on the opposite side to the fin, and a convex portion protruding from the surface on the fin side of the first base, and a second member arranged on the fin side of the two members includes a flat plate-shaped second base in contact with the first base and a recessed portion in which the convex portion is fitted while being recessed from the plate surface of the second base.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a heat sink and a method for manufacturing a heat sink. [Background technology]

[0002] Conventionally, heat sinks with excellent heat dissipation properties have been proposed. For example, Patent Document 1 describes a heat sink in which the substrate is a composite plate made of a copper plate and an aluminum plate, aluminum heat dissipation fins are provided on the surface of the aluminum plate of the composite plate, and the interface of the composite plate is metal-bonded. The heat sink described in Patent Document 2 is composed of a base, fins, and a thermal conductor, and is a heat sink in which the base has the thermal conductor arranged thereon and multiple fins are arranged upright on the base. The thermal conductor has a higher thermal conductivity than the material of the base, and is arranged within the region of the base so that one continuous thermal conductor intersects with the virtual extension planes of all of the fins. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-298259 [Patent Document 2] JP 2019-192783 A Summary of the Invention [Problem to be solved by the invention]

[0004] When a heat sink is made up of two components made of different materials, repeated thermal expansion and contraction can cause the two components to peel off due to stress generated by the difference in linear expansion between the two components. An object of the present invention is to provide a heat sink or the like that can prevent separation between two members made of different materials. [Means for solving the problem]

[0005] The present invention, which was completed with this objective in mind, is a heat sink having a flat base portion and a number of fins protruding from the plate surface of the base portion and is constructed from two members made of different materials, wherein the first member, which is the member of the two members arranged on the opposite side to the fins, has a flat first base portion with a flat surface opposite the fins and a convex portion protruding from the surface of the first base facing the fins, and the second member of the two members arranged on the fin side has a flat second base portion in contact with the first base and a concave portion that is recessed from the plate surface of the second base and into which the convex portion fits. Here, the first base portion, the second base portion, the convex portion, and the concave portion may be located in the base portion. The protrusion may be conical. The protrusion may be cylindrical. The protruding portion may have a cross-sectional area in a plane perpendicular to the protruding direction at the base end portion smaller than a cross-sectional area in the same plane at the tip end portion. Furthermore, the tip of the protrusion may reach the fin. Also, from another perspective, the present invention is a heat sink having a flat base portion and a plurality of fins protruding from a plate surface of the base portion and being constructed from two members of different materials, wherein a first member, which is one of the two members arranged on the opposite side to the fins, has a flat first base portion and a recess that is recessed from the plate surface of the first base or penetrates the first base, and a second member, which is one of the two members arranged on the fin side, has a flat second base portion in contact with the first base and a convex portion that protrudes from the plate surface of the second base and fits into the recess. Here, the recess may be cylindrical. Moreover, the fins may be formed on a partial region of the base portion, and the first member may be provided so as to come into contact with the second member in the region of the second member where the fins are formed. Also, from another perspective, the present invention is a method for manufacturing a heat sink having a flat base portion and a plurality of fins protruding from a plate surface of the base portion, in which two components made of different materials are stacked and the two components are pressurized with a mold that moves in the stacking direction, thereby forming the fins on one of the two components, flattening the surface of the other of the two components opposite the fins, and fitting a convex portion formed on the other component into a concave portion formed on the one of the components. Here, the other member may have a flat plate-like portion and the protrusion, and may be laminated such that a tip of the protrusion comes into contact with the one member. The protruding portion may have a cross-sectional area in a plane perpendicular to the protruding direction at the base end portion smaller than a cross-sectional area in the same plane at the tip end portion. Also, from another perspective, the present invention is a method for manufacturing a heat sink having a flat base portion and a plurality of fins protruding from a surface of the base portion, in which two components made of different materials are stacked together and the two components are pressurized with a mold that moves in the stacking direction to form the fins in one of the two components, and a recess that is a depression or through hole formed in the other of the two components is fitted into a protrusion formed in one of the components. Here, the other member may have a flat plate-like portion and the recess, and may be laminated such that a plate surface of the flat plate-like portion comes into contact with the one member. From another perspective, the present invention is a method for manufacturing a heat sink having a flat base portion and a plurality of fins protruding from a surface of the base portion, in which two components made of different materials are stacked together and pressurized with a mold that moves in the stacking direction to form the fins in one of the two components, and a convex portion formed in the other of the two components is fitted into a concave portion formed in the one of the two components, and a cutting process is performed on the portion of the other component opposite the fins to form a flat surface. Here, the linear expansion coefficient of the one member may be greater than the linear expansion coefficient of the other member, and the two members may be heated and then pressurized. Effect of the Invention

[0006] According to the present invention, it is possible to provide a heat sink or the like that can suppress separation between two members made of different materials. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is an example of an exploded view of components constituting the cooling device according to the embodiment. [Diagram 2] 1A is a diagram showing an example of a cross section of a cooling device, and FIG. 1B is a diagram showing an example of an enlarged view of part IIb in FIG. [Diagram 3] 5(a) and 5(b) are diagrams illustrating an example of a method for manufacturing the heat sink according to the first embodiment. [Figure 4] 1A and 1B are diagrams illustrating an example of a heat sink capable of cooling a plurality of semiconductor modules. [Diagram 5] 13(a) and 13(b) are diagrams showing an example of a modified example of a protrusion. [Figure 6] 13(a) and 13(b) are diagrams showing an example of a modified example of a protrusion. [Figure 7] FIG. 11 is a diagram illustrating an example of a heat sink according to a second embodiment. [Figure 8] 11(a) and 11(b) are diagrams illustrating an example of a method for manufacturing a heat sink according to a second embodiment. [Figure 9] 13A and 13B are diagrams showing an example of a modified example of a recess of the first member. [Figure 10] 13A and 13B are diagrams illustrating an example of a heat sink according to a third embodiment. [Figure 11] 13(a), (b), and (c) are diagrams illustrating an example of a manufacturing method for a heat sink according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. FIG. 1 is an example of an exploded view of components constituting a cooling device 100 according to an embodiment. Fig. 2(a) is a diagram showing an example of a cross section of the cooling device 100. Fig. 2(b) is a diagram showing an example of an enlarged view of part IIb in Fig. 2(a). The cooling device 100 includes a heat sink 1 having fins 3, and a bottomed, concave jacket 101 which, together with the heat sink 1, forms a space through which a cooling liquid flows. The material of the jacket 101 can be, for example, aluminum. The cooling device 100 also includes an O-ring 102 that seals between the heat sink 1 and the jacket 101, and bolts 103 that join the heat sink 1 and the jacket 101. The cooling device 100 also includes an inlet pipe 104 that introduces the cooling liquid into the jacket 101, and an outlet pipe 105 that introduces the cooling liquid from inside the jacket 101.

[0009] The cooling device 100 is a liquid-cooling type cooling device that cools a semiconductor module 90, which is an example of a heat generating body, by using a cooling liquid and a heat sink 1. The semiconductor module 90 has an insulating substrate 91, a wiring layer 92 provided on the insulating substrate 91, and a semiconductor element 93 attached to the wiring layer 92 via a solder layer 94. The semiconductor module 90 also has a heat transfer layer 95 that transfers heat from the insulating substrate 91 to the cooling device 100. The heat transfer layer 95 of the semiconductor module 90 is joined to the surface of the heat sink 1 opposite to the jacket 101. Examples of a method for joining the heat transfer layer 95 to the heat sink 1 include brazing, soldering, sintering, adhesion with resin, and attachment with thermally conductive grease.

[0010] (Heat sink 1 according to the first embodiment) The heat sink 1 according to the first embodiment includes a flat base 2 and a plurality of fins 3 protruding from a plate surface of the base 2. A semiconductor module 90 is joined to the center of the base 2, and the plurality of fins 3 are provided in an area of ​​the same size as the area in which the semiconductor module 90 is provided, on the side of the base 2 opposite to the side to which the semiconductor module 90 is joined.

[0011] As shown in FIG. 1, the base portion 2 may be, for example, in the shape of a rectangular parallelepiped. The fins 3 may be, for example, columnar in shape, with the protruding direction from the base portion 2 being the columnar direction. The cross-sectional shape of the fins 3 on a plane perpendicular to the protruding direction may be, for example, circular or elliptical. The cross-sectional shape may be, for example, quadrangular, such as a square, rectangle, or rhombus. The fins 3 may be flat. If the fins 3 are flat, they may be parallel to the direction from the inlet pipe 104 to the outlet pipe 105, or may be wavy having a portion inclined in the direction from the inlet pipe 104 to the outlet pipe 105.

[0012] The heat sink 1 is composed of two members made of different materials, a first member 10 and a second member 20. The first member 10 is made of copper, and the second member 20 is made of aluminum. Of the two components constituting the heat sink 1, the first member 10 is the member disposed on the opposite side to the fins 3. The first member 10 has a flat plate-like first base 11 with a flat outer surface 11p, which is the surface opposite to the fins 3, and a protrusion 12 protruding from an inner surface 11q, which is the surface of the first base 11 facing the fins 3. The second member 20 has a flat second base 21 in contact with the first base 11, a recess 22 recessed from the plate surface of the second base 21 and into which the protrusion 12 of the first member 10 fits, and a peripheral portion 23 protruding from the outer periphery of the second base 21 toward the first member 10. The second member 20 also has fins 3.

[0013] In the heat sink 1 according to the first embodiment, the first base 11, the second base 21, the protrusion 12, the recess 22, and the peripheral portion 23 are in the base portion 2. In other words, the base portion 2 is composed of the first base 11 and the protrusion 12 of the first member 10, and the second base 21, the recess 22, and the peripheral portion 23 of the second member 20. The fins 3 are composed of the second member 20. The first member 10 is provided so as to contact the second member 20 in the region in which the fins 3 are formed in the second member 20. The region in which the first member 10 is provided is larger than the region in which the heat transfer layer 95 of the semiconductor module 90 is provided, so that the heat generated by the semiconductor module 90 is transferred to the first member 10. Outside the region in which the fins 3 are provided in the base portion 2, a through hole 2a through which the bolt 103 passes is formed. Furthermore, in the heat sink 1 of the first embodiment, the convex portion 12 of the first member 10 has an inverted tapered shape in which the area of ​​the cross-sectional shape at the base end 12b in a plane perpendicular to the protruding direction is smaller than the area of ​​the cross-sectional shape at the tip end 12t in the same plane.

[0014] 3(a) and 3(b) are diagrams that diagrammatically show an example of a manufacturing method for the heat sink 1 according to the first embodiment. The heat sink 1 is manufactured by a forging apparatus 200 used for so-called closed forging. In the forging device 200, a first material 110 which is the base of the first member 10 and a second material 120 which is the base of the second member 20 are stacked together, and the first material 110 and the second material 120 are pressed together using a first die 210 and a second die 220 which move relatively in the stacking direction. The material of the first material 110 is copper, and the material of the second material 120 is aluminum.

[0015] The first material 110 has a flat plate-like portion 111 and a plurality of protruding portions 112 protruding from the flat plate-like portion 111 toward the second material 120. The protruding portions 112 are inversely tapered in that the area of ​​the cross-sectional shape in a plane (not shown) perpendicular to the protruding direction at the base end portion 112b is smaller than the area of ​​the cross-sectional shape in the same plane at the tip end portion 112t. For example, the first material 110 can be formed by forming a plurality of cylindrical portions protruding from the flat plate-like portion 111 toward the second material 120, and then compressing and crushing the cylindrical portions in the protruding direction to form the inversely tapered protruding portions 112. The second material 120 has a flat plate-shaped portion 121 and a peripheral portion 122 that protrudes from the outer periphery of the flat plate-shaped portion 121 toward the first material 110.

[0016] The first die 210 has a support surface 211 that supports the flat plate portion 121 of the second material 120, and a plurality of recesses 212 recessed from the support surface 211. The shape of the recesses 212 is a base shape for the shape of the fins 3 of the heat sink 1, and can be, for example, a cylindrical shape or a rectangular prism shape. The recesses 212 of the first die 210 may be through holes, and a metal mold separate from the first die 210 may be inserted into the through holes to determine the length of the fins 3. The second mold 220 may be, for example, in the shape of a rectangular parallelepiped.

[0017] When manufacturing the heat sink 1, as shown in Figure 3 (a), with the flat portion 121 of the second material 120 supported by the first mold 210, the first material 110 is placed within the peripheral portion 122 of the second material 120 so that the tip surfaces of the multiple protrusions 112 contact the flat portion 121 of the second material 120.

[0018] Thereafter, the second die 220 is moved relative to the first die 210 to apply pressure to the first material 110 and the second material 120 . When the first material 110 and the second material 120 are pressurized, as shown in Fig. 3(b), the second material 120 undergoes plastic flow and fills the recesses 212 of the first die 210. The second material 120 also undergoes plastic flow and fills the spaces between the convex portions 112 of the first material 110 and between the convex portions 112 and the surrounding portion 122, and the first material 110 is compressed.

[0019] After being manufactured using the forging device 200, the second material 120 filled in the recess 212 of the first die 210 becomes the fin 3 of the heat sink 1. The first material 110 and the portion of the second material 120 other than the portion filled in the recess 212 of the first die 210 become the base portion 2 of the heat sink 1. The flat plate portion 111 and the protruding portion 112 of the first material 110 correspond to the first base portion 11 and the protruding portion 12 of the first member 10, respectively. The peripheral portion 122 of the second material 120 corresponds to the peripheral portion 23 of the second member 20. The portion of the flat plate portion 121 of the second material 120 other than the portion filled in the recess 212 of the first die 210 corresponds to the second base portion 21, and the recess 123 into which the protruding portion 112 of the first material 110 is fitted becomes the recess 22 of the second member 20. In other words, the second material 120 is pressurized by the first die 210 and the second die 220, and a part of the flat portion 121 of the second material 120 fits around the protrusion 112 of the first material 110, thereby forming the recess 22 of the second member 20.

[0020] The manufacturing method described above is a method for manufacturing a heat sink 1 having a flat base portion 2 and a plurality of fins 3 protruding from a plate surface of the base portion 2. Then, in a state in which a first material 110 and a second material 120 as an example of two members made of different materials are stacked, the first material 110 and the second material 120 are pressed by a die moving in the stacking direction, whereby the fins 3 are formed in the second material 120 as an example of one member, the surface of the first material 110 as an example of the other member opposite to the fins 3 is flattened, and the protrusions 112 formed in the first material 110 and the recesses 123 formed in the second material 120 are fitted together.

[0021] The process of compressing and crushing the cylindrical portion in order to form the convex portion 112 of the first material 110 into an inverted taper shape may be performed before placing the first material 110 in the forging apparatus 200, or may be performed by pressurizing the first material 110 together with the second material 120 using the first die 210 and the second die 220 after placing the first material 110 in the forging apparatus 200. Furthermore, the manufacturing method of the heat sink 1 is not limited to closed forging, but may be open forging.

[0022] In the heat sink 1 manufactured by the above manufacturing method, the first member 10, which is one of the two members and is disposed on the opposite side to the fins 3, has a flat first base 11 having a flat outer surface 11p as an example of the surface on the opposite side to the fins 3, and a protrusion 12 protruding from the surface of the first base 11 on the fin 3 side. The second member 20, which is one of the two members and is disposed on the fin 3 side, has a flat second base 21 in contact with the first base 11 and a recess 22 recessed from the plate surface of the second base 21 and into which the protrusion 12 fits. According to this heat sink 1, the protrusion 12 of the first member 10 fits into the recess 22 of the second member 20, so that the bonding strength of the interface between the first member 10 and the second member 20 can be increased. As a result, according to the heat sink 1, it is possible to suppress peeling between the first member 10 and the second member 20. Furthermore, for example, if a first member 10 made of copper and a second member 20 made of aluminum are joined by a process that requires heat input, such as welding or brazing, brittle compounds are produced and the strength is reduced. However, in the heat sink 1, the first member 10 and the second member 20 are mechanically integrated, so the strength of the heat sink 1 can be increased.

[0023] Furthermore, in the heat sink 1, the protrusion 12 is inversely tapered in that the area of ​​the cross-sectional shape in a plane perpendicular to the protruding direction at the base end 12b is smaller than the area of ​​the cross-sectional shape in the plane at the tip end 12t. Since the recess 22 of the second member 20 is formed so as to follow the shape of the protrusion 12, the protrusion 12 is unlikely to come out of the recess 22, so that the separation between the first member 10 and the second member 20 can be suppressed. When forming the heat sink 1 by forging using the forging device 200, hot forging may be performed by heating the first material 110 and the second material 120 to a high temperature, or cold forging may be performed at a temperature close to room temperature without heating. However, when hot forging is performed, the second material 120 is more likely to enter between the protrusions 112 and the protrusions 112 even if the protrusions 112 of the first material 110 are inversely tapered than when cold forging is performed. Furthermore, since the linear expansion coefficient of the second material 120 is greater than that of the first material 110, when the temperature returns to room temperature after hot forging, the force with which the recess 22 of the second member 20 fastens the protrusion 12 of the first member 10 becomes greater, thereby suppressing peeling between the first member 10 and the second member 20. Furthermore, for example, when the cross-sectional area of ​​the protrusion 12 at the base end 12b is the same as the height of the protrusion 12, the protrusion 12 having an inverse tapered shape has a larger surface area than the cross-sectional area at the tip end 12t. As a result, the heat transfer performance from the first member 10 to the second member 20 is improved.

[0024] In the cooling device 100 having the heat sink 1, the semiconductor module 90 is joined to the first member 10 made of copper, which has a higher thermal conductivity than aluminum, and therefore the cooling performance is higher than that of a configuration in which the semiconductor module 90 is joined to aluminum. In addition, it is the second member 20 made of aluminum, not the first member 10, that comes into contact with the coolant in the jacket 101. Therefore, it is possible to prevent corrosion of parts made of aluminum due to the presence of copper in the cooling system. In addition, since the entire heat sink 1 is not made of copper, it is possible to achieve lower cost and lighter weight compared to a case in which the entire heat sink 1 is made of copper. The heat sink 1 is composed of two members, the first member 10 and the second member 20, but is not limited to being composed of two members. The heat sink 1 may include members other than the first member 10 and the second member 20.

[0025] 4(a) and 4(b) are diagrams showing an example of a heat sink 1 capable of cooling a plurality of semiconductor modules 90. Note that Fig. 4 shows a configuration capable of cooling three semiconductor modules 90. The heat sink 1 described using FIG. 1 and the like is configured to be capable of cooling one semiconductor module 90. However, when cooling a plurality of semiconductor modules 90, as shown in FIG. 4, a fin group region 4 in which a plurality of fins 3 are formed may be provided in an area of ​​the same size as the area in which each of the plurality of semiconductor modules 90 is provided. As shown in FIG. 4, a plurality of first members 10 made of copper may be provided so as to contact the second member 20 in each of the plurality of fin group regions 4 formed in the second member 20. In other words, the same number of first members 10 as the fin group regions 4 may be provided so as to cover the entire surface of the portion of the second base portion 21 of the second member 20 opposite to each of the fin group regions 4. This shape makes it possible to achieve lower cost and weight reduction compared to a case in which a member made of copper is provided on the entire surface on the semiconductor module 90 side.

[0026] (Modification of the protrusion 12 of the first member 10) 5(a) and 5(b) are diagrams showing an example of a modified example of the protrusion 12. In FIG. The protrusion 12 may be, for example, cylindrical as shown in FIG. 5(a). Even if the protrusion 12 is cylindrical, the protrusion 12 of the first member 10 and the recess 22 of the second member 20 can be fitted together to increase the bonding strength at the interface between the first member 10 and the second member 20, and peeling between the first member 10 and the second member 20 can be suppressed. In addition, compared to the case where the protrusion 12 is tapered, when the cross-sectional area at the base end 12b and the height of the protrusion 12 are the same, the surface area is larger when the protrusion 12 is cylindrical. As a result, the heat transfer performance from the first member 10 to the second member 20 is improved. In addition, by making the protrusion 112 of the first material 110 cylindrical, the protrusion 12 of the first member 10 can be made cylindrical by the manufacturing method using the forging device 200 described above.

[0027] Furthermore, the protrusion 12 may be, for example, conical as shown in Fig. 5(b). Even if the protrusion 12 is conical, the protrusion 12 of the first member 10 and the recess 22 of the second member 20 are fitted together, thereby increasing the bonding strength of the interface between the first member 10 and the second member 20 and suppressing peeling between the first member 10 and the second member 20. By making the protrusion 112 of the first material 110 conical, the protrusion 12 of the first member 10 can be made conical in the manufacturing method using the forging device 200 described above.

[0028] Alternatively, a third material (not shown) having only a flat plate-like portion may be used as the base material of the first member 10, and the third material may be placed in the peripheral portion 122 so as to contact the flat plate-like portion 121 of the second material 120, and then pressed using the first die 210 and the second die 220. When the third material and the second material 120 are pressed, the second material 120 undergoes plastic flow and fills the recess 212 of the first die 210. In addition, with the plastic flow of the second material 120, the third material also undergoes plastic flow toward the recess 212 of the first die 210, forming a cone-shaped protrusion protruding from the flat plate-like portion. By manufacturing in this manner, the protrusion 12 of the first member 10 may be made cone-shaped.

[0029] 6(a) and 6(b) are diagrams showing an example of a modified example of the protrusion 12. In FIG. The tip 12 t of the protrusion 12 may reach the fin 3 . For example, the protrusion 12 may be conical as shown in FIG. 6(a), and the tip 12t of the protrusion 12 and a part of the recess 22 into which the protrusion 12 fits may form the fin 3. 6(b), the protrusion 12 may be cylindrical, and the fin 3 may be formed by a portion of the protrusion 12 on the tip end 12t side and a portion of the recess 22 into which the protrusion 12 fits. Although not shown, the protrusion 12 may be inversely tapered, and the portion of the protrusion 12 on the tip end 12t side and a portion of the recess 22 into which the protrusion 12 fits may form the fin 3. Although not shown, the protrusion 12 may be flat, and the portion of the protrusion 12 on the tip end 12t side and a portion of the recess 22 into which the protrusion 12 fits may form the fin 3. In this manner, by configuring the tip 12t of the protrusion 12 to reach the fin 3, the heat transfer performance from the first member 10 to the second member 20 is improved.

[0030] (Heat sink 31 according to the second embodiment) FIG. 7 is a diagram showing an example of a heat sink 31 according to the second embodiment. The heat sink 31 according to the second embodiment includes a flat base portion 32 and a plurality of fins 33 protruding from the plate surface of the base portion 32. The heat sink 31 is composed of two members made of different materials, a first member 40 and a second member 50. The first member 40 is made of copper, and the second member 50 is made of aluminum. The base portion 32 and the fins 33 are similar to the base portion 2 and the fins 3 according to the first embodiment, respectively, so the following mainly describes the differences.

[0031] Of the two components constituting the heat sink 31, the first member 40 is the component disposed on the opposite side to the fins 33. The first member 40 has a flat plate-like first base 41 having a flat outer surface 411 that is the surface opposite to the fins 33, and a recess 42 recessed from an inner surface 412 that is the surface of the first base 41 facing the fins 33. The second member 50 has a flat second base 51 in contact with the first base 41, a protrusion 52 protruding from the plate surface of the second base 51 and fitting into the recess 42 of the first member 40, and a peripheral portion 53 protruding from the outer periphery of the second base 51 toward the first member 40. The second member 50 also has fins 33.

[0032] 8(a) and 8(b) are diagrams illustrating an example of a manufacturing method for the heat sink 31 according to the second embodiment. The heat sink 31 is manufactured in the same manner as the heat sink 1 by the forging device 200 using a first die 210 and a second die 220 . In the forging device 200, a first material 140 which is the base of the first member 40 and a second material 150 which is the base of the second member 50 are stacked together, and the first material 140 and the second material 150 are pressed together using a first die 210 and a second die 220 which move relatively in the stacking direction. The material of the first material 140 is copper, and the material of the second material 150 is aluminum.

[0033] The first material 140 has a flat plate-shaped portion 141 and a plurality of recesses 142 recessed from the flat plate-shaped portion 141 in a direction opposite to the second material 150. The recesses 142 can be, for example, cylindrical. The second material 150 has a flat plate-shaped portion 151 and a peripheral portion 152 that protrudes from the outer periphery of the flat plate-shaped portion 151 toward the first material 140.

[0034] As shown in FIG. 8(a), with the flat portion 151 of the second material 150 supported by the first mold 210, the first material 140 is placed within the peripheral portion 152 of the second material 150 so as to contact the flat portion 151 of the second material 150. Thereafter, the second die 220 is moved relative to the first die 210 to apply pressure to the first material 140 and the second material 150 . When the first material 140 and the second material 150 are pressurized, as shown in Fig. 8(b), the second material 150 undergoes plastic flow and fills the recess 212 of the first die 210. Also, the second material 150 undergoes plastic flow and fills the recess 142 of the first material 140, and the first material 140 is compressed.

[0035] After the second material 150 is manufactured using the forging device 200, the second material 150 filled in the recess 212 of the first die 210 becomes the fin 33 of the heat sink 31. The first material 140 and the portion of the second material 150 other than the portion filled in the recess 212 of the first die 210 become the base portion 32 of the heat sink 31. The flat plate portion 141 and the recess 142 of the first material 140 correspond to the first base portion 41 and the recess 42 of the first member 40, respectively. The protruding portion 153, which is the portion of the second material 150 that fits into the recess 142 of the first material 140, becomes the protruding portion 52 of the second member 50. The peripheral portion 152 of the second material 150 becomes the peripheral portion 53 of the second member 50. Furthermore, the portion of the flat portion 151 of the second material 150 other than the portion filled in the recess 212 of the first mold 210 and the portion other than the protrusion 153 fitted into the recess 142 of the first material 140 becomes the second base 51.

[0036] (Modifications of the recess 42 of the first member 40) FIG. 9 is a diagram showing an example of a modified example of the recess 42 of the first member 40. As shown in FIG. The recess 42 of the first member 40 may be a hole penetrating the first base portion 41, as shown in FIG. The protrusion 52 of the second member 50 may be fitted into the recess 42 so as to penetrate through the first base portion 41. In this way, even if the recess 42 of the first member 40 is made into a hole penetrating the first base 41 and the protrusion 52 of the second member 50 is structurally fitted into this hole, the bonding strength at the interface between the first member 40 and the second member 50 can be increased, and peeling between the first member 40 and the second member 50 can be suppressed. Furthermore, by making the recess 142 of the first material 140 a hole penetrating the flat portion 141, it is possible to manufacture the heat sink 31 in which the protrusion 52 of the second member 50 fits into the recess 42 of the first base 41 in the forging device 200 using the first die 210 and the second die 220, as described with reference to Figure 8.

[0037] The manufacturing method described above is a method for manufacturing a heat sink 31 having a flat base portion 32 and a plurality of fins 33 protruding from a plate surface of the base portion 32. Then, in a state in which a first material 140 and a second material 150 as an example of two members made of different materials are stacked, the first material 140 and the second material 150 are pressed by a die moving in the stacking direction, thereby forming the fins 33 in the second material 150 as an example of one of the members, and fitting the recessed portion 142, which is a recess or a through hole formed in the first material 140 as an example of the other member, into the protruding portion 153 formed in the second material 150. When the heat sink 31 is formed by forging using the forging device 200, either hot forging or cold forging may be performed.

[0038] In the heat sink 31 manufactured by the manufacturing method described above, the first member 40, which is one of the two members and is disposed on the opposite side to the fins 33, has a flat first base 41 and a recess 42 that is recessed from the plate surface of the first base 41 or penetrates the first base 41, and the second member 50, which is one of the two members and is disposed on the fin 33 side, has a flat second base 51 that contacts the first base 41 and a protrusion 52 that protrudes from the plate surface of the second base 51 and fits into the recess 42. According to this heat sink 31, the protrusion 52 of the second member 50 is structurally fitted into the recess 42 of the first member 40, thereby increasing the bonding strength at the interface between the first member 40 and the second member 50, and thus preventing the first member 40 and the second member 50 from peeling off. Furthermore, since the recesses 42 and the protrusions 52 are cylindrical, the contact area between the first member 10 and the second member 20 is larger than when, for example, the recesses 42 and the protrusions 52 are conical, and therefore the heat transfer performance from the first member 10 to the second member 20 can be improved.

[0039] (Heat sink 61 according to the third embodiment) FIG. 10 is a diagram showing an example of a heat sink 61 according to the third embodiment. The heat sink 61 according to the third embodiment includes a flat base portion 62 and a plurality of fins 63 protruding from the plate surface of the base portion 62. The heat sink 61 is composed of two members made of different materials, a first member 70 and a second member 80. The first member 70 is made of copper, and the second member 80 is made of aluminum. The following mainly describes the differences between the heat sink 1 according to the first embodiment and the heat sink 61 according to the third embodiment.

[0040] Of the two components constituting the heat sink 61, the first member 70 is the component disposed opposite the fins 63. The first member 70 has a flat plate-like first base 71 having a flat outer surface 71p, which is the surface opposite the fins 63, and a protrusion 72 protruding from the first base 71. The second member 80 has a flat second base portion 81 in contact with the first base portion 71, and a recess portion 82 that is recessed from the plate surface of the second base portion 81 and into which the protrusion portion 72 of the first member 70 fits. The second member 80 also has fins 63.

[0041] 11(a), 11(b), and 11(c) are views that diagrammatically show an example of a manufacturing method for the heat sink 61 according to the third embodiment. The heat sink 61 can be produced, for example, by performing a press process in a press machine 300 using a third die 230 and a fourth die 240, and then performing a cutting process. The press processing machine 300 stacks a first material 170 that forms the basis of a first member 70 and a second material 180 that forms the basis of a second member 80, and presses the first material 170 and the second material 180 using a third die 230 and a fourth die 240 that move relatively in the stacking direction.

[0042] The first material 170 and the second material 180 are in the form of a flat plate, the first material 170 is made of copper, and the second material 180 is made of aluminum. The third die 230 has a support surface 231 that supports the lower surface 181 of the second material 180, and a recess 232 that is recessed from the support surface 231 and is provided at a position facing a protrusion 242 (described later) of the fourth die 240. The shape of the recess 232 is the base shape of the fin 63, and can be, for example, a cylindrical shape or a square prism shape. The fourth mold 240 has a rectangular parallelepiped base (not shown) and a plurality of protrusions 242 protruding from the base. The protrusions 242 can be, for example, cylindrical or rectangular prism-shaped.

[0043] First, in the first step, as shown in FIG. 11(b), the fourth die 240 is moved toward the third die 230, and the second material 180 supported by the third die 230 and the first material 170 superimposed on the second material 180 are pressed by the third die 230 and the fourth die 240. As a result, the portion of the first material 170 pressed by the protrusion 242 of the fourth die 240 moves toward the recess 232 of the third die 230, and the portion of the second material 180 corresponding to the protrusion 242 of the fourth die 240 is pressed by the first material 170 and moves, filling the recess 232 of the third die 230. As a result, the recess 171 and the protrusion 172 are formed in the first material 170, and the recess 182 and the protrusion 183 are formed in the second material 180.

[0044] 11(c), in the second step, cutting is performed to remove the recesses 171 in the first material 170 after the first step and form a flat surface 173. In other words, the second step is a step of processing the first material 170 flat to remove any traces of pressure applied by the fourth die 240. The surface 173 after being processed flat corresponds to the outer surface 71p of the heat sink 61 and becomes the surface that comes into contact with the semiconductor module 90.

[0045] The protrusions 183 of the second material 180 correspond to the fins 63, the recesses 182 of the second material 180 correspond to the recesses 82 of the second member 80, and the protrusions 172 of the first material 170 correspond to the protrusions 72 of the first member 70. In the heat sink 61, the first member 70 covers the entire surface of the second base portion 81 of the second member 80 on the opposite side to the fins 63.

[0046] The manufacturing method described above is a method for manufacturing a heat sink 61 having a flat base portion 62 and a plurality of fins 63 protruding from the plate surface of the base portion 62. In this manufacturing method, a first material 170 and a second material 180 made of different materials are laminated, and the first material 170 and the second material 180 are pressed by a die moving in the lamination direction to form the fins 63 on the second material 180 as an example of one of the two members. In this manufacturing method, a convex portion 172 formed on the first material 170 as an example of the other of the two members is fitted into a concave portion 182 formed on the second material 180, and a cutting process is performed on a portion of the first material 170 opposite to the fins 63 to form a flat surface 173.

[0047] According to the heat sink 61 manufactured by the above manufacturing method, the convex portion 72 of the first member 70 is structurally fitted into the concave portion 82 of the second member 80, so that the bonding strength of the interface between the first member 70 and the second member 80 can be increased. As a result, according to the heat sink 61, it is possible to suppress peeling between the first member 70 and the second member 80. Also, since the first member 70 formed of copper and the second member 80 formed of aluminum are mechanically integrated, for example, the strength of the heat sink 61 can be increased compared to a case where joining is performed that requires heat input, such as welding or brazing. [Explanation of symbols]

[0048] 1,31,61...heat sink, 2,32,62...base portion, 3,33,63...fin, 10,40,70...first member, 11,41,71...first base portion, 12,52,72,112,153,172,183...projection portion, 20,50,80...second member, 21,52,82...second base portion, 22,42,82,123,1 42, 171, 182, 212, 232...recess, 90...semiconductor module, 91...insulating substrate, 92...wiring layer, 93...semiconductor element, 94...solder layer, 95...heat transfer layer, 110, 140, 170...first material, 120, 150, 180...second material, 210...first type, 220...second type, 230...third type, 240...fourth type

Claims

1. A heat sink having a flat base portion and a plurality of fins protruding from a plate surface of the base portion, the heat sink being configured with two members made of different materials, The first member, which is the member of the two members arranged on the opposite side to the fin, has a flat first base portion with a flat surface on the opposite side to the fin and a convex portion protruding from a surface of the center of the first base portion on the fin side, and the second member of the two members arranged on the fin side has a flat second base portion in contact with the first base portion and a concave portion recessed from the plate surface of the second base portion and into which the convex portion fits, the convex portion protruding from a surface surrounding the convex portion toward the fin, and the concave portion recessed from a surface surrounding the concave portion toward the fin. heat sink.

2. The first base portion, the second base portion, the protrusion portion, and the recess portion are located on the base portion. The heat sink of claim 1 .

3. The convex portion is cone-shaped. The heat sink according to claim 1 or 2.

4. The protrusion is cylindrical. The heat sink according to claim 1 or 2.

5. The area of ​​the cross-sectional shape of the protruding portion in a plane perpendicular to the protruding direction at the base end is smaller than the area of ​​the cross-sectional shape of the protruding portion in the plane at the tip end. The heat sink according to claim 1 or 2.

6. The tip of the protrusion reaches the fin. The heat sink of claim 1 .

7. A heat sink having a flat base and a plurality of fins protruding from a plate surface of the base, the heat sink being made of two members made of different materials, Of the two members, a first member, which is a member disposed on the opposite side to the fin, has a flat first base and a recess penetrating the first base, and a second member, which is disposed on the fin side of the two members, has a flat second base in contact with the first base and a protrusion protruding from a plate surface of the second base and fitting into the recess. heat sink.

8. The recess is cylindrical.

8. The heat sink of claim 7.

9. The fin is formed on a partial region of the base portion, The first member is provided so as to come into contact with the second member in a region where the fins are formed in the second member. The heat sink according to any one of claims 1 to 8.

10. A method for manufacturing a heat sink having a flat base portion and a plurality of fins protruding from a plate surface of the base portion, comprising the steps of: In a state where two members made of different materials are stacked, the two members are pressed by a die that moves in the stacking direction, thereby forming the fins on one of the two members, flattening the surface of the other of the two members opposite the fins, and fitting a convex portion formed on the other member into a concave portion formed on the one member, the other member has a flat plate-like portion and the protruding portion, Before the pressure is applied, the two members are laminated together so that the tip of the protrusion comes into contact with one of the members. A method for manufacturing a heat sink.

11. The area of ​​the cross-sectional shape of the protruding portion in a plane perpendicular to the protruding direction at the base end is smaller than the area of ​​the cross-sectional shape of the protruding portion in the plane at the tip end. The method for manufacturing the heat sink according to claim 10.

12. A method for manufacturing a heat sink having a flat base portion and a plurality of fins protruding from a plate surface of the base portion, comprising the steps of: In a state where two members made of different materials are stacked, the two members are pressed by a die that moves in the stacking direction, thereby forming the fin in one of the two members, and fitting a concave portion, which is a recess or a through hole formed in the other of the two members, into a convex portion formed in the one member; the other member has a flat plate-like portion and the recess, Before the pressure is applied, the two members are laminated so that the plate surface of the flat plate portion and one of the members are in contact with each other. A method for manufacturing a heat sink.

13. A method for manufacturing a heat sink having a flat base portion and a plurality of fins protruding from a plate surface of the base portion, comprising the steps of: In a state where two members made of different materials are stacked, the two members are pressed by a first mold and a second mold that move relatively in a stacking direction, thereby forming the fin on one of the two members, and fitting a convex portion formed on the other of the two members into a concave portion formed on the one member, A cutting process is performed on a portion of the other member opposite to the fin to form a flat surface; the first die has a support surface that supports the one member and a plurality of recesses recessed from the support surface, The second mold has a protrusion provided at a position facing the recess of the first mold. A method for manufacturing a heat sink.

14. the linear expansion coefficient of the one member is greater than the linear expansion coefficient of the other member, The two components are heated and then pressed together. A method for manufacturing a heat sink according to any one of claims 10 to 13.

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