Power semiconductor device and power conversion device

Abstract

In the present invention, a first surface shape of a module base (10) and a second surface shape of a heat sink base (14) are fitted together, as a result of which the module base (10) and the heat sink base (14) are fixed together. One of the first surface shape and the second surface shape includes a first protrusion (51) and a second protrusion (52), and the other of the two surface shapes includes a first recess (51) that fits with the first protrusion (51) and a second recess (62) that fits with the second protrusion (52). The first protrusion (51) has a tip end that contacts the first recess (61), and the second protrusion (52) has a tip end (TE) that is set apart from the second recess (62).

Description

[Technical Field]

[0001] The present disclosure relates to a power semiconductor device and a power conversion device, and more particularly to a power semiconductor device having a heat sink base and a power conversion device having the power semiconductor device. [Background technology]

[0002] International Publication No. 2018 / 079396 (Patent Document 1) discloses a semiconductor device. The semiconductor device includes a power module and a heat dissipation member. The power module includes a semiconductor element, a metal component on which the semiconductor element is mounted, and a sealing material that seals the semiconductor element and exposes at least a portion of the metal component. The metal component has either a plurality of recesses or protrusions, and the heat dissipation member has the other of a plurality of recesses or protrusions. The metal component and the heat dissipation member are integrated at a plurality of uneven portions where the plurality of recesses and the plurality of protrusions come into contact. A first uneven portion that is part of the plurality of uneven portions has a larger height dimension than a second uneven portion that is one of the plurality of uneven portions other than the first uneven portion.

[0003] In the above-described method for manufacturing a semiconductor device, the recessed and protruding portions are crimped together to integrate the metal part and the heat dissipation member. In this process, the first recessed and protruding portions, which form the first protruding and recessed portions having a height dimension greater than that of the second protruding and recessed portions, function as a guide mechanism to prevent the power module from being integrated with the heat sink in a tilted or misaligned manner relative to the original joining state. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2018 / 079396 Summary of the Invention [Problem to be solved by the invention]

[0005] If the relative positions of the components to be integrated by the crimping process deviate from the ideal design position due to at least one of tilt between the components and misalignment between the components, the load required to complete the crimping process, i.e., the required load, may increase. While the above-described semiconductor device can suppress misalignment using a guide mechanism, this does not necessarily result in sufficient suppression. Therefore, even if a guide mechanism is provided, there may be concerns about an increase in the required load due to misalignment. Furthermore, depending on the design of the semiconductor device, providing a guide mechanism may not be permitted. While a guide mechanism is unnecessary if a precise alignment process is performed before the crimping process, introducing such a process imposes a significant burden on the manufacturing process. Furthermore, not only misalignment but also dimensional errors of the components can increase the required load.

[0006] As described above, manufacturing variations that cause misalignment and / or dimensional errors can increase the load required for crimping. On the other hand, simply adjusting the design of the concave-convex portion to reduce the required load is likely to lead to a decrease in the strength of the crimped joint and an increase in the thermal contact resistance in the crimped joint.

[0007] The present disclosure has been made to solve the above-mentioned problems, and one of its purposes is to provide a power semiconductor device that can suppress an increase in the load required for crimping due to manufacturing variations, while also suppressing a decrease in the strength of the crimped joint and an increase in thermal contact resistance at the crimped joint. [Means for solving the problem]

[0008] The power semiconductor device according to the present disclosure includes a module base, a semiconductor element, a resin encapsulant, and a heat sink base. The module base has a mounting surface and a back surface opposite the mounting surface in a thickness direction. The semiconductor element is mounted on the mounting surface of the module base. The resin encapsulant encapsulates the semiconductor element on the mounting surface of the module base. The heat sink base has an attachment surface attached to the back surface of the module base and a heat dissipation surface opposite the attachment surface in the thickness direction. A first surface shape of the back surface of the module base and a second surface shape of the attachment surface of the heat sink base are fitted together, thereby fixing the back surface of the module base and the attachment surface of the heat sink base to each other. One of the first surface shape and the second surface shape includes a first convex portion and a second convex portion, and the other includes a first concave portion that fits with the first convex portion and a second concave portion that fits with the second convex portion. The first protrusion has a tip that contacts the first recess, and the second protrusion has a tip that is spaced apart from the second recess. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to suppress an increase in the load required for crimping due to manufacturing variations, while also suppressing a decrease in the strength of the crimped joint and an increase in thermal contact resistance in the crimped joint. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view schematically showing a configuration of a power semiconductor device in a first embodiment. [Figure 2] 2 is a cross-sectional view schematically showing the state of the power semiconductor device shown in FIG. 1 before the module base and the heat sink base are joined by caulking. [Figure 3] 3 is a partial plan view schematically showing the configuration of the back surface of the module base shown in FIG. 2. FIG. [Figure 4]4 is a partial plan view showing a modified example of the rear surface of the module base shown in FIG. 3. FIG. [Figure 5] 4 is a partial plan view showing a modified example of the rear surface of the module base shown in FIG. 3. FIG. [Figure 6] 2 is a partial cross-sectional view schematically illustrating the configuration of a second protrusion and a second recess shown in FIG. 1. FIG. [Figure 7] FIG. 10 is a partial cross-sectional view schematically showing a state immediately before a crimping step in a manufacturing method of a power semiconductor device according to a comparative example. [Figure 8] FIG. 10 is a partial cross-sectional view schematically showing a state immediately after a crimping step in a manufacturing method of a power semiconductor device according to a comparative example. [Figure 9] 1 is a partial cross-sectional view schematically showing a state immediately before a caulking step in the manufacturing method of the power semiconductor device in the first embodiment. [Figure 10] FIG. 10 is a partial cross-sectional view schematically showing a state immediately after a crimping step in a manufacturing method of a power semiconductor device according to a comparative example. [Figure 11] FIG. 3 is a cross-sectional view showing a modified example of the heat sink shown in FIG. 2. [Figure 12] FIG. 3 is a cross-sectional view showing a modified example of the heat sink shown in FIG. 2. [Figure 13] 3 is a cross-sectional view schematically showing a state before the module base and the heat sink base of a modified example of the power semiconductor device shown in FIG. 2 are joined by caulking. FIG. [Figure 14] 14 is a partial cross-sectional view illustrating the dimensions of the module base and the heat sink base shown in FIG. 13. FIG. [Figure 15] 3 is a cross-sectional view schematically showing a state before the module base and the heat sink base of a modified example of the power semiconductor device shown in FIG. 2 are joined by caulking. FIG. [Figure 16] 3 is a cross-sectional view schematically showing a state before the module base and the heat sink base of a modified example of the power semiconductor device shown in FIG. 2 are joined by caulking. FIG. [Figure 17]3 is a cross-sectional view schematically showing a state before the module base and the heat sink base of a modified example of the power semiconductor device shown in FIG. 2 are joined by caulking. FIG. [Figure 18] 1 is a cross-sectional view schematically showing a state immediately before a caulking step in a manufacturing method of a power semiconductor device in the first embodiment. [Figure 19] 4 is a cross-sectional view schematically showing a state during a caulking step in the manufacturing method of the power semiconductor device in the first embodiment. FIG. [Figure 20] 4 is a cross-sectional view schematically showing a state immediately after a caulking step in the manufacturing method of the power semiconductor device in the first embodiment. FIG. [Figure 21] FIG. 10 is a plan view illustrating a modified example of the caulking step in the manufacturing method of the power semiconductor device in the first embodiment. [Figure 22] FIG. 10 is a cross-sectional view schematically showing a modified example of the caulking step in the manufacturing method of the power semiconductor device in the first embodiment. [Figure 23] FIG. 10 is a cross-sectional view schematically showing a configuration of a power semiconductor device in a second embodiment. [Figure 24] 24 is a cross-sectional view schematically showing the state of the power semiconductor device shown in FIG. 23 before the module base and the heat sink base are joined by caulking. FIG. [Figure 25] FIG. 11 is a cross-sectional view schematically showing a configuration of a power semiconductor device according to a third embodiment. [Figure 26] FIG. 11 is a cross-sectional view schematically showing a step in a method of manufacturing a power semiconductor device in accordance with a third embodiment. [Figure 27] FIG. 11 is a cross-sectional view schematically showing a step in a method of manufacturing a power semiconductor device in accordance with a third embodiment. [Figure 28] FIG. 10 is a block diagram schematically showing a configuration of a power conversion device according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments will be described with reference to the drawings. In the following drawings, the same or corresponding parts are designated by the same reference numerals, and the description thereof will not be repeated. In addition, in this specification, the term "metal" can mean not only pure metals but also alloys, unless otherwise specified.

[0012] <First Embodiment> FIG. 1 is a cross-sectional view schematically showing the configuration of a power semiconductor device 101 according to the first embodiment. The power semiconductor device 101 includes a power module unit 1 and a heat sink unit 2. The power semiconductor device 101 is a device in which the power module unit 1 and the heat sink unit 2 are integrated, in other words, a heat sink-integrated power module. FIG. 2 is a cross-sectional view schematically showing a state before a module base 10 of the power module unit 1 and a heat sink base 14 of the heat sink unit 2 are joined by crimping. Note that crimping of the module base and the heat sink base may be referred to as "heat sink crimping" hereinafter. Note that the timing of heat sink crimping in the manufacture of the power semiconductor device 101 is not limited to one, and this also applies to the other embodiments. FIG. 2 above corresponds to a case in which heat sink crimping is performed independently in the final manufacturing process.

[0013] The power module section 1 includes a module base 10, at least one semiconductor element 5 (semiconductor chip), and a resin sealing section (mold) 4. The power module section 1 may also include a lead frame 3.

[0014] The module base 10 has a mounting surface PM and a back surface PO opposite the mounting surface PM in the thickness direction (the vertical direction in FIGS. 1 and 2). The semiconductor element 5 is mounted on the mounting surface PM of the module base 10. For example, a bonding material 6 made of solder may be used for this mounting. The semiconductor element 5 includes a power semiconductor element. The power semiconductor element is, for example, a switching element or a freewheeling diode. The semiconductor element 5 may be a semiconductor element using a wide bandgap semiconductor, i.e., a wide bandgap semiconductor element. The wide bandgap semiconductor is, for example, silicon carbide (SiC). A resin sealing portion 4 seals the semiconductor element 5 on the mounting surface PM of the module base 10. A lead frame 3 (metal electrodes) may be attached to the mounting surface PM of the module base 10, and an insulating sheet 9 may be provided between the lead frame 3 and the mounting surface PM. The lead frame 3 is electrically connected to the semiconductor element 5. Note that a wiring member (typically, a bonding wire) not shown may be used for this electrical connection. The lead frame 3 has a portion covered with the resin sealing portion 4 and a portion protruding from the resin sealing portion 4 to the outside.

[0015] The heat sink section 2 includes a heat sink base 14. The heat sink base 14 has a mounting surface PF attached to the rear surface PO of the module base 10, and a heat dissipation surface PR opposite the mounting surface PF in the thickness direction. In this embodiment, the heat sink section 2 also includes heat dissipation fins 15 attached to the heat dissipation surface PR of the module base 10. The heat dissipation fins 15 are attached to the crimping section 11 of the module base 10 by crimping. This crimping may be referred to as "fin crimping" below.

[0016] The module base 10 of the power module unit 1 and the heat sink base 14 of the heat sink unit 2 are prepared separately and then joined to each other by heat sink caulking. Therefore, the design of the heat sink unit 2 can be changed without changing the design of the module base 10, and this change can adjust the heat dissipation capacity for removing heat from the semiconductor element 5. Design elements of the heat sink unit 2 for adjusting the heat dissipation capacity include, for example, the dimensions of the heat sink base 14 in the in-plane direction perpendicular to the thickness direction, the number of heat dissipation fins 15, and the size of each heat dissipation fin 15. Changing the design of the heat sink unit 2 according to the required heat dissipation capacity allows the use of a common module base 10 design, thereby improving the productivity of the power module unit 1. Furthermore, there is no need to change the design of the mold used to manufacture the module base 10, which avoids increases in mold costs.

[0017] The module base 10 is made of metal. For example, the module base 10 is made of aluminum or an aluminum alloy and is produced by cutting, die-casting, forging, or extrusion. The heat sink base 14 is made of metal. For example, the heat sink base 14 is made of aluminum or an aluminum alloy and is produced by cutting, die-casting, forging, or extrusion. The heat dissipation fins 15 are made of a metal plate (rolled material) such as aluminum or an aluminum alloy.

[0018] The surface shape of the back surface PO of the module base 10 (hereinafter also referred to as the "first surface shape") and the surface shape of the mounting surface PF of the heatsink base 14 (hereinafter also referred to as the "second surface shape") fit together as shown in FIG. 1, thereby fixing the back surface PO of the module base 10 to the mounting surface PF of the heatsink base 14. One of the first surface shape and the second surface shape includes a first protrusion 51 and a second protrusion 52, and the other includes a first recess 61 that fits with the first protrusion 51 and a second recess 62 that fits with the second protrusion 52. In the example shown in FIGS. 1 and 2, the second surface shape includes the first protrusion 51 and the second protrusion 52, and the first surface shape includes the first recess 61 and the second recess 62.

[0019] FIG. 3 is a partial plan view schematically illustrating the configuration of the rear surface PO (FIG. 2) of the module base 10. The planar layout, perpendicular to the thickness direction, of the recess group 60 including the first recess 61 and the second recess 62 includes a plurality of patterns each extending along a first direction (the vertical direction in FIG. 3) and spaced apart in a second direction (the horizontal direction in FIG. 3) perpendicular to the first direction. Note that the protrusion group including the first protrusion 51 and the second protrusion 52 may also have a planar layout corresponding to the above planar layout. FIGS. 4 and 5 are partial plan views illustrating modifications of FIG. 3. In these modifications, the planar layout, perpendicular to the thickness direction, of the recess group 60 includes a plurality of patterns P1 each extending along the first direction (the vertical direction in FIG. 3) and spaced apart in a second direction (the horizontal direction in FIG. 3) perpendicular to the first direction, and at least one pattern P2 extending along a third direction (the horizontal direction in FIG. 3) different from the first direction. In particular, the modified example of FIG. 5 includes a pattern that extends discontinuously along the first direction, as indicated by the two-dot chain line in the figure.

[0020] FIG. 6 is a partial cross-sectional view schematically illustrating the configuration of the second protrusion 52 and the second recess 62 in a cross-section parallel to the thickness direction. The second protrusion 52 has a tip TE spaced apart from the second recess 62. A gap GP is therefore formed between the second protrusion 52 and the second recess 62. In the example of FIG. 6, the tip TE of the second protrusion 52 protrudes at a substantially uniform height H52 from the substantially flat surface of the mounting surface PF (the lower surface in FIG. 6). While the tip TE of the second protrusion 52 is spaced apart from the second recess 62, the side surface of the second protrusion 52 contacts the side wall of the second recess 62. The height H52 is preferably 0.5 mm or greater. The tip TE of the second protrusion 52 has a width W52 of the second protrusion 52. The second recess 62 has a width W62 at the position of the tip TE of the second protrusion 52 in the thickness direction. The width W52 is preferably 65% ​​or more and less than 100% of the width W62. Here, the width dimension is the dimension in a direction perpendicular to the extension direction, for example, the dimension in the horizontal direction in any of Figures 3 to 5. The distance HG between the tip TE of the second protrusion 52 and the bottom surface of the second recess 62 is greater than zero and may be 0.1 mm or more, or may be 0.2 mm or more.

[0021] The first protrusion 51 (FIG. 1) has a tip that contacts the first recess 61. In a cross-sectional view parallel to the thickness direction (FIG. 1), a gap does not need to be formed between the first protrusion 51 and the first recess 61, but a gap may be formed between the first protrusion 51 and the first recess 61. The gap is preferably smaller than the gap GP (FIG. 6) between the second protrusion 52 and the second recess 62, and preferably has an area that is 50% or less of the area of ​​the first recess 61. The height H52 (FIG. 6) of the second protrusion 52 is preferably smaller than the height of the first protrusion 51.

[0022] A surface pressure is applied at least locally between the first protrusion 51 and the first recess 61 for the purpose of crimping. A surface pressure does not necessarily need to be applied between the second protrusion 52 and the second recess 62, but a surface pressure may be applied at least locally. When a surface pressure is applied, the maximum surface pressure between the second protrusion 52 and the second recess 62 is preferably lower than the maximum surface pressure between the first protrusion 51 and the first recess 61. In the cross-sectional view illustrated in FIG. 6, a surface pressure SP1 and a surface pressure SP2 are applied to the right and left sides of the first protrusion 51, respectively. As a variant, the surface pressure SP1 or the surface pressure SP2 may be zero, and as another variant, the surface pressure SP1 and the surface pressure SP2 may be zero.

[0023] Note that a fluid (typically air) may flow through the gap GP (FIG. 6) during operation of the power semiconductor device 101, thereby promoting heat dissipation from the heat sink portion 2. This effect is particularly noticeable when forced air cooling using a fan or the like is applied.

[0024] The processing condition may also be inspected by observing the gap GP during or after the heat sink crimping process. For example, the area of ​​the gap GP in an in-plane direction perpendicular to the extension direction of the second recess 62 may be observed. Such observation may be performed, for example, by measuring the projected area of ​​light passing through the gap GP. The heat sink crimping condition can be automatically inspected by an automatic inspection device having a mechanism for performing such measurements.

[0025] 7 and 8 are partial cross-sectional views each schematically showing a state immediately before and after a crimping step in a method for manufacturing a power semiconductor device according to a comparative example. FIGS. 9 and 10 are partial cross-sectional views each schematically showing a state immediately before and after a crimping step in a method for manufacturing a power semiconductor device 101 according to the first embodiment. The press load for crimping is set to be approximately the same in the comparative example (FIGS. 7 and 8) and the first embodiment. Unlike the heat sink base 14 according to the present embodiment (FIGS. 9 and 10), the heat sink base 14Z according to the comparative example (FIGS. 7 and 8) has a second recess 62 but does not have a second protrusion 52 (FIGS. 9 and 10: this embodiment).

[0026] In the crimping process of the comparative example (FIGS. 7 and 8), if crimping is started when the misalignment between the heat sink base 14Z and the module base 10 is significant enough to be unnegligible, the module base 10 must undergo plastic deformation so that the first recess 61 expands more than when there is substantially no misalignment. Since the second recess 62 is completely hollow, the second recess 62 can shrink relatively freely to accommodate the expansion of the first recess 61. Therefore, even if there is a certain degree of misalignment, there is almost no increase in the load required for crimping. Meanwhile, the shrinkage of the second recess 62 reduces the surface pressure between the first protrusion 51 and the first recess 61. As a result, there is a concern that the strength of the crimped joint may decrease and the thermal contact resistance of the crimped joint may increase.

[0027] On the other hand, in the crimping process of the present embodiment 1 (FIGS. 9 and 10), a second protrusion 52 is provided on the heat sink base 14. Immediately before the crimping process (FIG. 9), at least one of the following first and second conditions is satisfied. As the first condition, the height H52B of the second protrusion 52 is smaller than the depth H62B of the second recess 62. As the second condition, the width W52B of the tip of the second protrusion 52 is smaller than the width W62B of the bottom of the second recess 62.

[0028] In the crimping process of the first embodiment (FIGS. 9 and 10), if crimping is initiated when the misalignment between the heat sink base 14 and the module base 10 is significant enough to be unnegligible, the module base 10 must be plastically deformed so that the first recess 61 expands more than when there is substantially no misalignment. At this time, because the second protrusion 52, which is smaller than the second recess 62, is inserted into the second recess 62, the second recess 62 contracts to absorb the expansion of the first recess 61, and as a result, contact between the second recess 62 and the second protrusion 52 progresses, further increasing the surface pressure therebetween. Due to the contraction of the second recess 62, the surface pressure between the first protrusion 51 and the first recess 61 decreases. This leads to a decrease in the strength of the crimped joint and an increase in the thermal contact resistance in the crimped joint. On the other hand, as described above, the contact between the second recess 62 and the second protrusion 52 progresses and the surface pressure therebetween increases, which leads to an increase in the strength of the crimped joint and a decrease in the thermal contact resistance at the crimped joint. Therefore, it is possible to suppress the decrease in the strength of the crimped joint and the increase in the thermal contact resistance at the crimped joint, which are concerns in the comparative example.

[0029] According to the first embodiment, the first protrusion 51 has a tip (FIG. 1) that contacts the first recess 61, and the second protrusion 52 has a tip TE (FIG. 6) that is separated from the second recess 62. This allows the first protrusion 51 and the first recess 61 to be crimped before the second protrusion 52 and the second recess 62 are crimped during the crimping process in the manufacture of the power semiconductor device 101. At this time, due to manufacturing variations that cause at least one of misalignment and dimensional error, the crimping of the first protrusion 51 and the first recess 61 may not proceed smoothly. If the crimping process continues in this case, the surface pressure between the first protrusion 51 and the first recess 61 increases, which causes plastic deformation that shrinks the second recess 62. This plastic deformation suppresses the increase in surface pressure between the first protrusion 51 and the first recess 61. Therefore, an excessive increase in the load required for the crimping process can be avoided. On the other hand, excessive shrinkage of the second recess 62 is prevented by being blocked by the second protrusion 52. Therefore, an excessively small surface pressure between the first protrusion 51 and the first recess 61 can be avoided. Therefore, a decrease in the strength of the crimped joint and an increase in the thermal contact resistance at the crimped joint, which would be caused by an excessively small surface pressure between the first protrusion 51 and the first recess 61, can be suppressed. From the above, it is possible to suppress an increase in the load required for the crimping process caused by manufacturing variations, while also suppressing a decrease in the strength of the crimped joint and an increase in the thermal contact resistance at the crimped joint.

[0030] The above-mentioned effects allow for a larger tolerance for misalignment during heat sink crimping, thereby improving the productivity of power semiconductor devices and allowing for the use of simpler jigs for heat sink crimping.

[0031] Furthermore, a large load required for the crimping process can reduce the productivity of power semiconductor devices or can damage components of the power semiconductor device, thereby reducing reliability. Examples of phenomena that can lead to reduced reliability include damage to the semiconductor element 5 (semiconductor chip), cracking of the semiconductor element 5, changes in the characteristics of the semiconductor element 5, cracking of the resin encapsulation portion 4, a decrease in the dielectric strength voltage of the power semiconductor device 101, or peeling between components of the power semiconductor device 101. By reducing the required load as described above, productivity or reliability can be improved. From another perspective, because the required load is reduced as described above, misalignment of the components to be crimped is more tolerable. This can increase the productivity of power semiconductor devices.

[0032] When the second protrusions 52 and the second recesses 62 come into contact with each other as a result of plastic deformation of the second recesses 62, this also contributes to suppressing an increase in thermal contact resistance. Furthermore, when surface pressure is applied between the second protrusions 52 and the second recesses 62, this also contributes to suppressing a decrease in bonding strength.

[0033] The surface of the heat dissipation fin 15 may be embossed to create minute depressions. The heat dissipation fin 15 may be manufactured by press processing using a mold, and if embossing is performed during this press processing, the increase in cost due to embossing can be largely avoided. The embossing increases the heat dissipation area, thereby improving heat dissipation performance. Furthermore, when heat dissipation fins 15 are stacked as components used in the manufacture of the power semiconductor device 101, if the heat dissipation fins 15 are embossed, the contact area between the heat dissipation fins 15 is reduced, thereby reducing surface friction between the heat dissipation fins 15. The reduced surface friction makes it possible to simplify the production equipment for fin crimping and shorten the production takt time, thereby improving productivity. Furthermore, if the heat dissipation fins 15 are embossed, during the fin crimping process, the crimped portions 11 of the heat sink base 14 penetrate deeper into the embossed portions of the surface of the heat dissipation fins 15 than into the non-embossed portions, thereby exerting an anchor effect and increasing friction in the thickness direction (the vertical direction in Figures 1 and 2) between the heat dissipation fins 15 and the crimped portions 11 of the heat sink base 14. This improves the vertical tensile strength of the heat dissipation fins 15 after the fin crimping process.

[0034] In particular, when the heat dissipation fins 15 are harder than the heat sink base 14, the crimping portions 11 of the heat sink base 14 only plastically deform along the surface of the heat dissipation fins 15 during the fin crimping process and are less likely to penetrate into the surface. Therefore, by performing embossing in advance, the vertical tensile strength of the heat dissipation fins after the fin crimping process is particularly improved. On the other hand, when the heat sink base 14 is harder than the heat dissipation fins 15, the crimping portions 11 of the heat sink base 14 are more likely to penetrate into the surface of the heat dissipation fins 15 during the fin crimping process, thereby providing an anchor effect. Therefore, when the heat sink base 14 is harder than the heat dissipation fins 15, the effect of embossing the heat dissipation fins 15 is smaller. Therefore, from the perspective of the vertical tensile strength of the heat dissipation fins 15 after the fin crimping process, it is preferable to at least one of emboss the surface of the heat dissipation fins 15 and select a material for the heat sink base 14 that is harder than the material for the heat dissipation fins 15. For example, when the material of the heat sink base 14 is an aluminum 6000-based material and the material of the heat dissipation fins 15 is an aluminum 1000-based material, the vertical tensile strength of the heat dissipation fins 15 is approximately 2.5 to 3.6 times higher than when the material of the heat sink base 14 and the material of the heat dissipation fins 15 are both aluminum 1000-based materials.

[0035] However, the materials of the heat sink base 14 and the heat dissipation fins 15 are not limited to aluminum-based materials and may be different materials. For example, from the perspective of heat dissipation capacity, heat dissipation capacity is improved by making the heat dissipation fins 15 from a copper-based plate material, which has a higher thermal conductivity than aluminum-based materials. Furthermore, the heat sink unit 2 is made by crimping and joining the heat sink base 14 and the heat dissipation fins 15, which are prepared separately. When making the heat sink base 14 and the heat dissipation fins 15, processing constraints (aspect ratio) of die-casting or extrusion processing do not become an issue. Therefore, the heat dissipation fins can be designed relatively freely to improve the heat dissipation capacity of the heat sink unit 2.

[0036] FIG. 11 is a cross-sectional view showing a heat sink 2M, which is a modified example of the heat sink 2 (FIG. 2). In producing the heat sink 2M, the heat sink base 14M and the heat dissipation fins 15M are integrally formed from the beginning, so fin crimping is not required. The heat sink 2M is produced by, for example, extrusion, cutting, or forging. FIG. 12 is a cross-sectional view showing a heat sink 2N, which is a modified example of the heat sink 2 (FIG. 2). In producing the heat sink 2N, the heat sink base 14N and the heat dissipation fins 15N are integrally formed from the beginning, so fin crimping is not required. The heat sink 2N is produced by, for example, die casting.

[0037] FIG. 13 is a cross-sectional view schematically illustrating a state before the module base 10A and the heat sink base 14A of a modified example of the power semiconductor device 101 (FIG. 2) are crimped and joined. The back surface PO of the module base 10A has a surface shape (first surface shape) provided with guide recesses 63. The depth of the guide recesses 63 is greater than the depths of the first recesses 61 and the second recesses 62. The mounting surface PF of the heat sink base 14A has a surface shape (second surface shape) provided with guide protrusions 53. The depth of the guide protrusions 53 is greater than the depths of the first protrusions 51 and the second protrusions 52. In the example shown in FIG. 13, the back surface PO of the module base 10A has guide recesses 63 at two locations (left and right in the figure) and the mounting surface PF of the heat sink base 14A has guide protrusions 53 at two locations (left and right in the figure). FIG. 14 is a partial cross-sectional view illustrating the dimensions of the module base 10A and the heat sink base 14A shown in FIG.

[0038] When starting the heat sink crimping process, the module base 10A and the heat sink base 14A can be roughly positioned using the guide protrusions 53 and the guide recesses 63. As the crimping process progresses, the guide protrusions 53 slide within the guide recesses 63, allowing for some correction of misalignment. This effect increases the allowable misalignment during the heat sink crimping process. This increases the productivity of power semiconductor devices. Furthermore, a simpler jig can be used for the heat sink crimping process.

[0039] In the heat sink crimping process, as described above, as the second recess 62 shrinks, the surface pressure between the second recess 62 and the second protrusion 52 increases, resulting in a certain increase in the load required for the crimping process. The degree of this increase can be appropriately controlled by adjusting the number and dimensions of the second protrusion 52 and the second recess 62. FIGS. 15 and 16 each show a modification from this perspective. In FIG. 15, the module base 10B has only one second recess 62, and the heat sink base 14B has only one second protrusion 52. In FIG. 16, the module base 10C has second recesses 62 at every other location between the first recesses 61, and the heat sink base 14B has second protrusions 52 at every other location between the first protrusions 51.

[0040] 17 is a cross-sectional view schematically showing a state before the module base 10 and the heat sink base 14 are crimped together in a modified example of the power semiconductor device 101 (FIG. 2). Contrary to the power semiconductor device 101 (FIG. 2), in this modified example, the surface shape (first surface shape) of the back surface PO of the module base 10D includes a first protrusion 51 and a second protrusion 52, and the surface shape (second surface shape) of the mounting surface PF of the heat sink base 14D includes a first recess 61 and a second recess 62. Note that the features of this modified example may also be applied to the modified examples of the first embodiment described above and other embodiments described later.

[0041] The heat sink crimping process and the fin crimping process described above may be performed simultaneously. FIGS. 18 to 20 are cross-sectional views each showing a state immediately before, during, and immediately after the crimping process in the manufacturing method of the power semiconductor device 101 (FIG. 1). Referring to FIGS. 18 and 19, the heat dissipation fins 15 are inserted into the fin insertion grooves 20 of the heat sink base 14. Then, a jig 21 is inserted into the crimping portion 11 of the heat sink base 14. Then, with the power module unit 1 in contact with the mounting surface PF of the heat sink base 14, a load is applied between the power module unit 1 and the jig 21 in the thickness direction. This allows the heat sink crimping process and the fin crimping process to be performed simultaneously. This method is suitable for the planar layout shown in FIG. 3.

[0042] The heat sink may be crimped by applying a load so that the back surface PO of the power module unit 1 is pressed against the mounting surface PF of the heat sink unit 2M (FIG. 11) or the heat sink unit 2N (FIG. 12) supported by a jig similar to jig 23. In this case, unlike jig 23, it is preferable that the tip of the jig has a wide flat surface without a tapered shape.

[0043] Alternatively, the heat sink crimping process may be performed after the fin crimping process. FIG. 21 is a plan view illustrating this method, and FIG. 22 is a cross-sectional view illustrating this method. In this method, a jig 23 is used to support the outer region PR2 of the heat dissipation surface PR of the heat sink section 2 formed by the fin crimping process, which surrounds the inner region PR1 to which the heat dissipation fins 15 are attached. The heat sink crimping process is performed by applying a load so that the back surface PO of the power module section 1 is pressed against the mounting surface PF of the heat sink section 2 supported by the jig 23. This method is suitable when the planar layout shown in FIG. 3 is not used (for example, when the planar layout shown in FIG. 4 or FIG. 5 is used).

[0044] <Embodiment 2> Fig. 23 is a cross-sectional view schematically showing the configuration of a power semiconductor device 102 in the second embodiment. The power semiconductor device 102 has a heat sink base 14S instead of the heat sink base 14 of the power semiconductor device 101 (Fig. 1). The rest of the configuration is almost the same as the configuration of the first embodiment (Figs. 1 and 2) described above. Fig. 24 is a cross-sectional view schematically showing the state of the power semiconductor device 102 shown in Fig. 23 before the module base 10 and the heat sink base 14S are crimped together.

[0045] The heat sink base 14S has an outer side surface PP opposite the heat dissipation surface PR (the lower surface of the heat sink base 14S in FIGS. 23 and 24), which is disposed outside the mounting surface PF in an in-plane direction perpendicular to the thickness direction (the horizontal direction in FIGS. 23 and 24). The outer side surface PP is disposed offset in the thickness direction toward the heat dissipation surface PR relative to the mounting surface PF (in other words, offset downward in FIGS. 23 and 24). As described above, in the second embodiment, in addition to the mounting surface PF, the outer side surface PP is provided as the surface opposite the heat dissipation surface PR. Therefore, in the second embodiment, the outer surface area of ​​the heat dissipation surface PR is larger than the outer surface area of ​​the mounting surface PF.

[0046] The heat sink base 14S can be considered to have a module mounting portion 14a forming a mounting surface PF and a thermal diffusion portion 14d forming an outer surface PP and a heat dissipation surface PR. The thermal diffusion portion 14d is separated from the module base 10 by the module mounting portion 14a. In the in-plane direction, the thermal diffusion portion 14d extends to the outside of the module mounting portion 14a. Note that the boundary between the module mounting portion 14a and the thermal diffusion portion 14d (the dashed line in Figures 23 and 24) may be imaginary.

[0047] The portion of the lead frame 3 protruding from the resin sealing portion 4 does not face the mounting surface PF in the thickness direction, but faces the outer surface PP at a distance D2. The distance D2 corresponds to the insulation distance (typically the distance separated by air) between the lead frame 3 and the heat sink base 14S. On the other hand, the insulation distance between the lead frame 3 and the heat sink base 14 (FIG. 1: Embodiment 1) corresponds to the distance D1 (FIG. 1), which is approximately the same as the thickness of the module base 10. Therefore, in order to increase the insulation distance in the above-described Embodiment 1, the thickness of the module base 10 must be increased. If the module base 10 is too thick, the productivity of the power semiconductor device will decrease. Specifically, first, the heat capacity of the module base 10 will increase, which increases the time required to raise the temperature to the process temperature in the process of forming the resin sealing portion 4, i.e., the molding process, in the manufacture of the power semiconductor device 101, thereby decreasing productivity. Second, the mold used in the molding process will become larger, which in turn increases the size of the equipment performing the molding process, thereby decreasing productivity. Third, larger mold dies for molding processes have larger heat capacities, which increases the time required to bring the dies up to process temperature, thereby reducing productivity.

[0048] According to the second embodiment, the outer surface PP is shifted in the thickness direction from the mounting surface PF toward the heat dissipation surface PR. This allows the distance between the lead frame 3 protruding from the resin sealing portion 4 and the outer surface PP of the heat sink base 14S facing it in the thickness direction, i.e., the insulation distance, to be increased without depending solely on the thickness of the module base 10.

[0049] <Third Embodiment> Fig. 25 is a cross-sectional view schematically showing the configuration of a power semiconductor device 103 according to the third embodiment. Fig. 26 and Fig. 27 are cross-sectional views schematically showing steps in a method for manufacturing power semiconductor device 103.

[0050] The heat sink base 14P includes a third recess 64 and a pin member 29 having an inserted portion inserted into the third recess 64 and a protruding portion protruding from the third recess 64. This protruding portion constitutes a second protrusion 52. Note that the boundary between the third recess 64 and the pin member 29 is actually observable. The third recess 64 of the heat sink base 14P is made of a first metal material, and the pin member 29 of the heat sink base 14P is made of a second metal material. Portions of the heat sink base 14P other than the pin member 29 may be made of the first metal material. The second metal material may be the same as or different from the first metal material. In the latter case, the second metal material is preferably harder than the first metal material, which suppresses plastic deformation of the second protrusion 52 during the heat sink crimping process. Therefore, the increase in the surface pressure between the second recess 62 and the second protrusion 52 due to the reduction in size of the second recess 62 can be made more rapid. This further enhances the effects described in the first embodiment. Note that the configuration other than the above is substantially the same as the configuration of the first embodiment (FIG. 1).

[0051] According to this embodiment, after forming the mounting surface PF having the first protrusions 51 (see FIG. 26), the pin members 29 are inserted to provide the second protrusions 52 on the mounting surface PF (see FIG. 27). This eliminates the need to form the second protrusions 52 simultaneously when forming the first protrusions 51. This reduces the difficulty of manufacturing the heat sink base 14P, taking into account the aspect ratio of the mounting surface PF, etc.

[0052] As a modified example, as described above with reference to FIG. 17, the second protrusion 52 and the third recess 64 into which it is inserted may be included in the surface shape (first surface shape) of the rear surface PO of the module base, instead of the surface shape (second surface shape) of the mounting surface PF of the heat sink base. In this case, the third recess 64 of the module base is made of a first metal material, and the pin member 29 of the module base is made of a second metal material. The parts of the module base other than the pin member 29 may be made of the first metal material. The second metal material may be the same as or different from the first metal material. In the latter case, the second metal material is preferably harder than the first metal material.

[0053] <Fourth Embodiment> In this embodiment, the power semiconductor device according to at least one of the above-described embodiments 1 to 3 is applied to a power conversion device. Although the application of the power semiconductor device according to embodiments 1 to 3 is not limited to a specific power conversion device, the following will describe, as embodiments 1 to 3, a case where the power semiconductor device according to at least one of embodiments 1 to 3 is applied to a three-phase inverter.

[0054] FIG. 28 is a block diagram showing the configuration of a power conversion system to which the power conversion device according to this embodiment is applied.

[0055] The power conversion system shown in Fig. 28 is composed of a power supply 100, a power conversion device 200, and a load 300. The power supply 100 is a DC power supply and supplies DC power to the power conversion device 200. The power supply 100 can be configured from a variety of elements, such as a DC system, a solar cell, or a storage battery, or it may be configured from a rectifier circuit or an AC / DC converter connected to an AC system. The power supply 100 may also be configured from a DC / DC converter that converts DC power output from a DC system into a predetermined power.

[0056] The power conversion device 200 is a three-phase inverter connected between the power source 100 and the load 300, and converts DC power supplied from the power source 100 into AC power and supplies the AC power to the load 300. As shown in Fig. 28 , the power conversion device 200 includes a main conversion circuit 201 that converts DC power into AC power and outputs it, and a control circuit 203 that outputs a control signal to the main conversion circuit 201 to control the main conversion circuit 201.

[0057] The load 300 is a three-phase electric motor driven by AC power supplied from the power conversion device 200. The load 300 is not limited to a specific application, but is an electric motor mounted on various electrical devices, and is used as an electric motor for, for example, a hybrid vehicle, an electric vehicle, a railroad car, an elevator, or an air conditioning device.

[0058] The power conversion device 200 will be described in detail below. The main conversion circuit 201 includes switching elements and freewheel diodes (not shown). The switching elements convert DC power supplied from the power supply 100 into AC power, which is supplied to the load 300. The main conversion circuit 201 can have a variety of specific circuit configurations. However, the main conversion circuit 201 according to this embodiment is a two-level, three-phase full-bridge circuit that can be configured with six switching elements and six freewheel diodes connected in anti-parallel to each switching element. Each switching element and each freewheel diode of the main conversion circuit 201 is configured by a semiconductor module 202 that corresponds to the power semiconductor device according to at least one of the first to third embodiments described above. Two of the six switching elements are connected in series to form upper and lower arms, and each upper and lower arm forms one phase (U phase, V phase, W phase) of the full-bridge circuit. The output terminals of each upper and lower arm, i.e., the three output terminals of the main conversion circuit 201, are connected to the load 300.

[0059] The main conversion circuit 201 also includes a drive circuit (not shown) that drives each switching element, but the drive circuit may be built into the semiconductor module 202, or may be provided separately from the semiconductor module 202. The drive circuit generates drive signals that drive the switching elements of the main conversion circuit 201 and supplies them to the control electrodes of the switching elements of the main conversion circuit 201. Specifically, in accordance with control signals from a control circuit 203 (described later), the drive circuit outputs to the control electrodes of each switching element a drive signal that turns the switching element on and a drive signal that turns the switching element off. When maintaining a switching element in the on state, the drive signal is a voltage signal (on signal) that is equal to or greater than the threshold voltage of the switching element, and when maintaining a switching element in the off state, the drive signal is a voltage signal (off signal) that is equal to or less than the threshold voltage of the switching element.

[0060] The control circuit 203 controls the switching elements of the main conversion circuit 201 so that the desired power is supplied to the load 300. Specifically, it calculates the time (on time) that each switching element of the main conversion circuit 201 should be in the on state based on the power to be supplied to the load 300. For example, the main conversion circuit 201 can be controlled by PWM control, which modulates the on time of the switching elements according to the voltage to be output. Then, it outputs a control command (control signal) to a drive circuit provided in the main conversion circuit 201 so that an on signal is output to a switching element that should be in the on state at each time point, and an off signal is output to a switching element that should be in the off state at each time point. In accordance with this control signal, the drive circuit outputs an on signal or an off signal as a drive signal to the control electrode of each switching element.

[0061] In the power conversion device according to this embodiment, the power semiconductor device according to at least one of the first to third embodiments is applied to include at least one of the switching element and the free wheel diode of the main conversion circuit 201. This can improve the productivity or reliability of the power conversion device.

[0062] In the present embodiment, an example has been described in which the power semiconductor device according to at least one of the first to third embodiments is applied to a two-level three-phase inverter, but the application of the power semiconductor device according to at least one of the first to third embodiments is not limited to this, and the power semiconductor device can be applied to various power conversion devices. In the present embodiment, the two-level power conversion device is described, but a three-level or multi-level power conversion device may also be used, and when power is supplied to a single-phase load, the power semiconductor device according to at least one of the first to third embodiments may be applied to a single-phase inverter. Furthermore, when power is supplied to a DC load or the like, the power semiconductor device according to at least one of the first to third embodiments can also be applied to a DC / DC converter or an AC / DC converter.

[0063] Furthermore, the power conversion device to which the power semiconductor device according to at least one of the first to third embodiments is applied is not limited to the case where the load is an electric motor, but can also be used, for example, as a power supply device for an electric discharge machine, a laser processing machine, an induction heating cooker, or a contactless power supply system, and can also be used as a power conditioner for a solar power generation system, a power storage system, etc.

[0064] It is possible to freely combine the embodiments, and to modify or omit the embodiments as appropriate.

[0065] <Additional Notes> Various aspects of the present disclosure are summarized below as appendices. (Appendix 1) a module base (10, 10A to 10D) having a mounting surface (PM) and a back surface (PO) opposite to the mounting surface (PM) in the thickness direction; a semiconductor element (5) mounted on the mounting surface (PM) of the module base (10, 10A to 10D); a resin sealing portion (4) that seals the semiconductor element (5) on the mounting surface (PM) of the module base (10, 10A to 10D); a heat sink base (14, 14A to 14D, 14M, 14N, 14P, 14S) having a mounting surface (PF) attached to the back surface (PO) of the module base (10, 10A to 10D) and a heat dissipation surface (PR) opposite the mounting surface (PF) in the thickness direction; Equipped with a first surface shape provided on the back surface (PO) of the module base (10, 10A to 10D) and a second surface shape of the mounting surface (PF) of the heat sink base (14, 14A to 14D, 14M, 14N, 14P, 14S) are fitted together, whereby the back surface (PO) of the module base (10, 10A to 10D) and the mounting surface (PF) of the heat sink base (14, 14A to 14D, 14M, 14N, 14P, 14S) are fixed to each other, one of the first surface shape and the second surface shape includes a first convex portion (51) and a second convex portion (52), and the other includes a first concave portion (61) that fits with the first convex portion (51) and a second concave portion (62) that fits with the second convex portion (52); The first protrusion (51) has a tip that contacts the first recess (61), and the second protrusion (52) has a tip (TE) that is away from the second recess (62). Power semiconductor devices (101-103, 101V). (Appendix 2) A power semiconductor device (101 to 103, 101V) described in Appendix 1, wherein, in a cross-sectional view parallel to the thickness direction, the height (H52) of the second convex portion is 0.5 mm or more, and the width (W52) of the second convex portion is 65% or more and less than 100% of the width (W62) of the second concave portion. (Appendix 3) A power semiconductor device (101-103, 101V) according to Appendix 1 or 2, wherein, in a cross-sectional view parallel to the thickness direction, no gap is formed between the first convex portion (51) and the first concave portion (61), or a gap smaller than the gap (GP) between the second convex portion (52) and the second concave portion (62) is formed between the first convex portion (51) and the first concave portion (61). (Appendix 4) A power semiconductor device (101-103, 101V) according to any one of Appendices 1 to 3, wherein, in a cross-sectional view parallel to the thickness direction, no gap is formed between the first convex portion (51) and the first concave portion (61), or a gap having an area of ​​50% or less of the area of ​​the first concave portion (61) is formed. (Appendix 5) The power semiconductor device (101-103, 101V) according to any one of appendices 1 to 4, wherein a surface pressure is applied at least locally between the first convex portion (51) and the first concave portion (61). (Appendix 6) A power semiconductor device (101-103, 101V) according to any one of appendices 1 to 5, wherein no surface pressure is applied between the second convex portion (52) and the second concave portion (62), or a maximum surface pressure lower than the maximum surface pressure between the first convex portion (51) and the first concave portion (61) is applied between the second convex portion (52) and the second concave portion (62). (Appendix 7) The power semiconductor device (101-103, 101V) according to any one of appendices 1 to 6, wherein a surface pressure is applied at least locally between the second convex portion (52) and the second concave portion (62). (Appendix 8) the heat sink base (14S) has an outer surface (PP) opposite to the heat dissipation surface (PR), the outer surface (PP) being arranged outside the mounting surface (PF) in an in-plane direction perpendicular to the thickness direction, The outer surface (PP) is arranged to be shifted toward the heat dissipation surface (PR) in the thickness direction relative to the mounting surface (PF). A power semiconductor device (102) according to any one of appendices 1 to 7. (Appendix 9) A power semiconductor device (101-103, 101V) described in any one of Appendices 1 to 8, wherein a planar layout perpendicular to the thickness direction of a recess group (60) including the first recess (61) and the second recess (62) includes a plurality of patterns each extending along a first direction and arranged at intervals in a second direction perpendicular to the first direction. (Appendix 10) A power semiconductor device (101-103, 101V) described in any one of Appendices 1 to 8, wherein the planar layout perpendicular to the thickness direction of a recess group (60) including the first recess (61) and the second recess (62) includes a plurality of patterns (P1) each extending along a first direction and arranged at intervals in a second direction perpendicular to the first direction, and at least one pattern (P2) extending along a third direction different from the first direction. (Appendix 11) The power semiconductor device (103) according to any one of Appendices 1 to 10, wherein the module base or the heat sink base includes a third recess (64) and a member (29) having an insertion portion inserted into the third recess (64) and a protruding portion protruding from the third recess (64), and the protruding portion constitutes the second protrusion (52). (Appendix 12) A main conversion circuit (201) having the power semiconductor device (101 to 103, 101V) according to any one of Supplementary Notes 1 to 11, which converts input power and outputs it; a control circuit (203) that outputs a control signal to the main conversion circuit (201) to control the main conversion circuit (201); A power conversion device (200) comprising: [Explanation of symbols]

[0066] 1 power module portion, 2, 2M, 2N heat sink portion, 3 lead frame, 4 resin sealing portion, 5 semiconductor element, 10, 10A to 10D module base, 14, 14A to 14D, 14M, 14N, 14P, 14S heat sink base, 15, 15M, 15N heat dissipation fin, 29 pin member, 51 first convex portion, 52 second convex portion, 60 recess group, 61 first recess, 62 second recess, 64 third recess, 101 to 103 power semiconductor device, 200 power conversion device, 201 main conversion circuit, 203 control circuit, PF mounting surface, PM mounting surface, PO back surface, PP outer surface, PR heat dissipation surface.

Claims

1. a module base having a mounting surface and a back surface opposite to the mounting surface in a thickness direction; a semiconductor device mounted on the mounting surface of the module base; a resin sealing portion that seals the semiconductor element on the mounting surface of the module base; a heat sink base having a mounting surface attached to the rear surface of the module base and a heat dissipation surface opposite the mounting surface in the thickness direction; Equipped with a first surface shape of the back surface of the module base and a second surface shape of the mounting surface of the heat sink base are fitted together, thereby fixing the back surface of the module base and the mounting surface of the heat sink base to each other; one of the first surface shape and the second surface shape includes a first convex portion and a second convex portion, and the other includes a first concave portion that fits with the first convex portion and a second concave portion that fits with the second convex portion; the first protrusion has a tip that contacts the first recess, and the second protrusion has a tip that is away from the second recess and is lower in height than the first protrusion; Power semiconductor devices.

2. A power semiconductor device as described in claim 1, wherein the first convex portions and the second convex portions are arranged alternately, and the first convex portions are arranged at the outermost periphery.

3. 3. The power semiconductor device according to claim 1, wherein, in a cross-sectional view parallel to the thickness direction, the height of the second convex portion is 0.5 mm or more, and the width of the second convex portion is 65% or more and less than 100% of the width of the second concave portion.

4. 3. The power semiconductor device according to claim 1, wherein, in a cross-sectional view parallel to the thickness direction, no gap is formed between the first convex portion and the first concave portion, or a gap smaller than the gap between the second convex portion and the second concave portion is formed between the first convex portion and the first concave portion.

5. 3. The power semiconductor device according to claim 1, wherein, in a cross-sectional view parallel to the thickness direction, no gap is formed between the first convex portion and the first concave portion, or a gap having an area of ​​50% or less of an area of ​​the first concave portion is formed between the first convex portion and the first concave portion.

6. 3. The power semiconductor device according to claim 1, wherein a surface pressure is applied at least locally between said first convex portion and said first concave portion.

7. 3. The power semiconductor device according to claim 1, wherein no surface pressure is applied between the second convex portion and the second concave portion, or a maximum surface pressure lower than a maximum surface pressure between the first convex portion and the first concave portion is applied between the second convex portion and the second concave portion.

8. 3. The power semiconductor device according to claim 1, wherein a surface pressure is applied at least locally between said second convex portion and said second concave portion.

9. the heat sink base has an outer surface opposite to the heat dissipation surface, the outer surface being arranged outside the mounting surface in an in-plane direction perpendicular to the thickness direction, The outer surface is disposed so as to be shifted toward the heat dissipation surface relative to the mounting surface in the thickness direction. The power semiconductor device according to claim 1 or 2.

10. 3. The power semiconductor device according to claim 1, wherein a planar layout perpendicular to the thickness direction of a group of recesses including the first recess and the second recess includes a plurality of patterns each extending along a first direction and spaced apart in a second direction perpendicular to the first direction.

11. 3. The power semiconductor device according to claim 1, wherein a planar layout perpendicular to the thickness direction of a group of recesses including the first recess and the second recess includes a plurality of patterns each extending along a first direction and spaced apart in a second direction perpendicular to the first direction, and at least one pattern extending along a third direction different from the first direction.

12. 3. The power semiconductor device according to claim 1, wherein the module base or the heat sink base includes a third recess and a member having an insertion portion inserted into the third recess and a protruding portion protruding from the third recess, the protruding portion constituting the second convex portion.

13. a main conversion circuit including the power semiconductor device according to claim 1 or 2, which converts input power and outputs the converted power; a control circuit that outputs a control signal to the main conversion circuit to control the main conversion circuit; A power conversion device comprising:

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