Semiconductor device, method for manufacturing semiconductor device, and electric power conversion device

Abstract

The purpose of the present invention is to provide a technology capable of reducing the reached temperature of a semiconductor module disposed on the most downstream side, and miniaturizing a heat sink. This semiconductor device comprises: a housing; a mounting plate fixed in the housing and having a plurality of openings; a plurality of heat sinks respectively attached to the plurality of openings in the mounting plate; a plurality of semiconductor modules respectively mounted on the plurality of heat sinks; and a cooling fan provided in the housing and blowing air to the plurality of heat sinks. The plurality of heat sinks are disposed along a first direction parallel to an air blowing direction of the cooling fan. Among the plurality of heat sinks, the dimension in a second direction orthogonal to the first direction of a heat sink disposed on the upstream side is smaller than the dimension in the second direction of a heat sink disposed on the downstream side.

Description

Semiconductor device, semiconductor device manufacturing method, and power conversion device

[0001] The present disclosure relates to a semiconductor device, a method for manufacturing a semiconductor device, and a power conversion device.

[0002] Conventionally, in a semiconductor device including a plurality of modular cooling devices each having a heat dissipation plate on which a heat generating element is arranged, and a housing to which the plurality of modular cooling devices are detachably connected, a housing has been proposed which includes an external frame, an opening formed to penetrate the interior of the external frame, and at least one bridge provided on the external frame to separate the opening and support the modular cooling device inserted into the opening (see, for example, Patent Document 1).

[0003] The semiconductor device further includes at least one airflow direction guide member that is inserted between the plurality of modular cooling devices and controls the flow of air flowing into the interior of the modular cooling device.

[0004] Patent No. 6448732

[0005] In a semiconductor device equipped with multiple semiconductor modules, heat generated by the semiconductor elements of each semiconductor module is dissipated by its respective heat sink, causing heated air to flow into the heat sinks of the other semiconductor modules, raising the temperatures reached by the other semiconductor modules. The temperature rise is particularly pronounced in the semiconductor module located furthest downwind. This causes thermal interference between the semiconductor modules within the semiconductor device. To avoid this thermal interference, it was necessary to enlarge the heat sinks.

[0006] Therefore, an object of the present disclosure is to provide a technology that reduces the temperature reached by a semiconductor module arranged on the most downwind side and enables the size of a heat sink to be reduced.

[0007] The semiconductor device according to the present disclosure comprises a housing, a mounting plate fixed within the housing and having a plurality of openings, a plurality of heat sinks attached to the plurality of openings of the mounting plate, a plurality of semiconductor modules mounted on the plurality of heat sinks, and a cooling fan provided in the housing for blowing air to the plurality of heat sinks, wherein the plurality of heat sinks are arranged along a first direction parallel to the blowing direction of the cooling fan, and the dimension in a second direction perpendicular to the first direction of the heat sink arranged on the upwind side of the plurality of heat sinks is smaller than the dimension in the second direction of the heat sink arranged on the downwind side.

[0008] According to the present disclosure, air with a small temperature rise that passes through a space where a heat sink arranged on the windward side is not arranged flows into a heat sink arranged on the downwind side, thereby reducing the temperature reached by a semiconductor module mounted on a heat sink arranged on the downwind side. This makes it possible to reduce the temperature reached by a semiconductor module arranged on the most downwind side and to reduce the size of the heat sink.

[0009] The objects, features, aspects, and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings.

[0010] 1 is a top view of a semiconductor device according to a first embodiment; FIG. 2 is a cross-sectional view of a heat sink-integrated semiconductor module; FIG. 3 is a cross-sectional view of a heat sink-integrated semiconductor module; FIG. 4 is a cross-sectional view of a heat sink-integrated semiconductor module; FIG. 5 is a bottom view of a semiconductor device according to a first embodiment; FIG. 6 is a contour diagram schematically showing the temperature of air flowing between heat dissipation fins provided in the semiconductor device according to the first embodiment; FIG. 7 is a cross-sectional view of another example of a semiconductor module; FIG. 8 is a cross-sectional view of another example of a semiconductor module; FIG. 9 is a bottom view of a semiconductor device according to a modified example of the first embodiment; FIG. 10 is a cross-sectional view of a semiconductor device according to a modified example of the first embodiment; FIG. 11 is a contour diagram schematically showing the temperature of air flowing between heat dissipation fins provided in the semiconductor device according to a modified example of the first embodiment; FIG. 12 is a cross-sectional view of a semiconductor device according to a modified example of the first embodiment; FIG. 13 is a contour diagram schematically showing the temperature of air flowing between heat dissipation fins provided in the semiconductor device according to a modified example of the first embodiment; Fig. 20 is a cross-sectional view taken along line AA of Fig. 19. Fig. 21 is a block diagram showing the configuration of a power conversion system to which a power conversion device according to a fourth embodiment is applied.

[0011] <First Embodiment> (Overall Configuration) The first embodiment will be described below with reference to the drawings. Fig. 1 is a top view of a semiconductor device 202 according to the first embodiment. Fig. 2 is a cross-sectional view of a heat sink-integrated semiconductor module 100. Fig. 3 is a cross-sectional view of a heat sink-integrated semiconductor module 100A. Fig. 4 is a cross-sectional view of a heat sink-integrated semiconductor module 100B. Fig. 5 is a bottom view of the semiconductor device 202 according to the first embodiment.

[0012] As shown in FIG. 1, the semiconductor device 202 includes a housing 20 , a mounting plate 21 , a plurality of (for example, six) heat sink-integrated semiconductor modules 100 , 100 A, and 100 B, and a cooling fan 22 .

[0013] The housing 20 is formed into a rectangular frame shape when viewed from above. The mounting plate 21 is formed into a rectangular shape when viewed from above and is fixed inside the housing 20. The mounting plate 21 is provided with a plurality of (e.g., six) openings (not shown) to which the heat sinks 13 of the plurality of heat sink-integrated semiconductor modules 100, 100A, and 100B are respectively attached. Two cooling fans 22 are provided on one of the short sides (the lower side in FIG. 1 ) of the housing 20. The cooling fans 22 blow air to the heat sinks 13 of the plurality of heat sink-integrated semiconductor modules 100, 100A, and 100B. The cooling fans 22 blow air in the direction of the arrow in FIG. 1 (from the bottom to the top in FIG. 1 ).

[0014] The heat sink-integrated semiconductor modules 100, 100A, 100B are arranged in two rows along a first direction parallel to the airflow direction of the cooling fan 22, and in each row, the heat sink-integrated semiconductor modules 100B, 100A, 100 are arranged in this order from the upwind side to the downwind side. Here, the upwind side is the lower side in Fig. 1, and the downwind side is the upper side in Fig. 1.

[0015] Next, a description will be given of the heat sink integrated semiconductor modules 100, 100A, and 100B. Because these modules have the same basic structure, only the heat sink integrated semiconductor module 100 will be described here.

[0016] 2 , the heat sink-integrated semiconductor module 100 includes a semiconductor module 10 and a heat sink 13. The semiconductor module 10 includes a plurality of semiconductor elements 1, a metal conductor 4 such as a lead frame, an insulating material 5 such as an insulating sheet, a fin base 9, a sealing material 7 such as an epoxy resin, a plurality of control terminals 6, and a plurality of main terminals 8.

[0017] A plurality of semiconductor elements 1 are mounted on the upper surface of a metal conductor 4 via a bonding material 2 such as solder. The semiconductor elements 1 and the metal conductor 4, and the semiconductor elements 1 themselves, are connected by wiring 3. The semiconductor elements 1 are Si-based semiconductor elements, SiC-based semiconductor elements, or compound semiconductor elements such as GaN.

[0018] The metal conductors 4 are arranged via insulating material 5 attached to the upper surface of the fin base 9. The sealing material 7 seals the semiconductor elements 1, the metal conductors 4, the insulating material 5, and the fin base 9 so that the main terminals 8, which are part of the metal conductors 4, and the lower surface of the fin base 9 are exposed.

[0019] The heat sink 13 has a heat sink base 11 that is integrated with the underside of the fin base 9, and a plurality of heat dissipation fins 12 that protrude downward (on the opposite side to the fin base 9) from the heat sink base 11. A first uneven portion 9a is provided on the underside of the fin base 9. In addition, a second uneven portion 11a that can fit into the first uneven portion 9a is provided on the upper surface of the heat sink base 11 (the surface facing the fin base 9) excluding the outer periphery.

[0020] The fin base 9 and heat sink 13 are integrated by fitting the first concave-convex portion 9a and the second concave-convex portion 11a together by press working. This allows the heat sink-integrated semiconductor module 100 to be grease-free. Because the heat sink-integrated semiconductor module 100 does not use thermal conductive grease, it has low thermal resistance and excellent long-term reliability. The fin base 9 is manufactured by cutting, forging, casting, extrusion, or other processes, and is made of aluminum or an aluminum alloy. However, the material of the fin base 9 is not limited to aluminum, and may be copper or other materials.

[0021] Furthermore, a crimped heat sink is used as the heat sink 13, in which the heat sink base 11 and the heat dissipation fins 12 are integrated by crimping. The heat sink base 11 of the crimped heat sink is made by cutting, die-casting, forging, extrusion, or the like, and is made of aluminum or an aluminum alloy.

[0022] Furthermore, by using a plate material (rolled material) such as aluminum or an aluminum alloy for the heat dissipation fins 12 of the crimped heat sink, it is possible to achieve both ease of processing and heat dissipation. The heat sink base 11 and the heat dissipation fins 12 of the crimped heat sink are not limited to being made of aluminum, and they may be made of a combination of different materials. For example, from the perspective of heat dissipation capacity, using a copper-based plate material, which has a higher thermal conductivity than aluminum-based materials, for the heat dissipation fins 12 will provide even greater heat dissipation capacity than aluminum-based materials.

[0023] When a crimped heat sink, in which the heat sink base 11 and the heat dissipation fins 12 are integrated by crimping, is used as the heat sink 13, there are no processing restrictions (aspect ratio) associated with die-casting, forging, or extrusion, so the heat dissipation fins 12 can be freely designed, improving the heat dissipation capacity of the heat sink 13. However, the heat sink 13 is not limited to a crimped heat sink, and similar effects can be achieved with a heat sink made by cutting, forging, extrusion, casting, or other processes.

[0024] Next, we will explain the different structures of the heat sink-integrated semiconductor modules 100, 100A, and 100B. As shown in Figures 1 and 5, a mounting plate 21 having openings in areas corresponding to the heat dissipation fins 12 of the heat sink 13 is fixed inside the housing 20, and the heat sink-integrated semiconductor modules 100, 100A, and 100B are attached and fixed to the openings in the mounting plate 21, thereby completing the semiconductor device 202.

[0025] Here, the dimension of the heat sink 13 arranged on the windward side among the plurality of heat sinks 13 in a second direction perpendicular to the first direction is smaller than the dimension of the heat sink 13 arranged on the downwind side in the second direction, where the second direction is the left-right direction in FIG.

[0026] 1, 3, and 4, the dimension in the second direction of the heat sink 13 of the heat sink-integrated semiconductor module 100B arranged on the upwind side is smaller than the dimension in the second direction of the heat sink 13 of the heat sink-integrated semiconductor module 100A arranged on the downwind side. Also, as shown in FIGS. 1 to 3, the dimension in the second direction of the heat sink 13 of the heat sink-integrated semiconductor module 100A arranged on the upwind side is smaller than the dimension in the second direction of the heat sink 13 of the heat sink-integrated semiconductor module 100 arranged on the downwind side. In other words, the dimension in the second direction of the heat sink 13 is smaller from the downwind side to the upwind side. The dimension in the first direction of the heat sink 13 of the heat sink-integrated semiconductor modules 100, 100A, and 100B is the same.

[0027] 2 to 5, the number of heat dissipation fins 12 is set according to the dimension of the heat sink 13 in the second direction. In other words, from the downwind side to the upwind side, the number of heat dissipation fins 12 decreases, and the area without heat dissipation fins 12 increases within the housing 20. Also, as shown in FIG. 1, the central axes 31 in the first direction of the heat sinks 13 in each row are aligned. Here, the central axis 31 in the first direction refers to an axis extending in the first direction that passes through the center in the second direction.

[0028] Next, a description will be given of the temperature of the air flowing between the heat dissipation fins 12. Fig. 6 is a contour diagram that schematically shows the temperature of the air flowing between the heat dissipation fins 12 included in the semiconductor device according to the first embodiment. Reference numeral 32 denotes a temperature contour.

[0029] As described above, the dimension in the second direction of the heat sink 13 arranged on the upwind side is smaller than the dimension in the second direction of the heat sink 13 arranged on the downwind side, so that air with a small temperature rise that passes through the portion on the upwind side where there are no heat dissipation fins 12 flows between the heat dissipation fins 12 of the heat sink 13 arranged on the downwind side. As a result, it is possible to reduce the average temperature of the air flowing between the heat dissipation fins 12 compared to a conventional configuration in which all heat sinks 13 have the same dimensions. Therefore, it is possible to reduce the temperature reached by the heat sink-integrated semiconductor module 100 arranged on the most downwind side compared to the above-mentioned conventional configuration.

[0030] 7 to 9 are cross-sectional views showing other examples of the semiconductor module 10. In Fig. 7, the semiconductor module 10 includes a metal plate 15 instead of the fin base 9. In Fig. 8, the main terminals 8 are bent upward in addition to the configuration of Fig. 7. In Fig. 9, the semiconductor module 10 includes a metal plate 15 instead of the fin base 9, and a resin case 17 is arranged to surround the periphery of the metal plate 15, and is filled with a sealing material 7.

[0031] The same effect as above can be obtained by mounting the semiconductor module 10 shown in Figures 7 to 9 on a heat sink 13 and thermally connecting them using a TIM (Thermal Interface Material) instead of the heat sink-integrated semiconductor modules 100, 100A, and 100B shown in Figures 2 to 4. This configuration can also be adopted in the modified example of the first embodiment, the second and third embodiments, and their modifications, which will be described below.

[0032] Here, the heat sink 13 is not limited to a caulked heat sink, and the same effect can be obtained with a heat sink made by cutting, forging, extrusion, casting, or the like.

[0033] Next, a modification of the first embodiment will be described. Fig. 10 is a bottom view of a semiconductor device 202 according to the modification of the first embodiment. Fig. 11 is a cross-sectional view of the semiconductor device 202 according to the modification of the first embodiment. Specifically, it is a cross-sectional view of a portion of the semiconductor device 202 according to the modification of the first embodiment where the heat sink-integrated semiconductor module 100 is arranged. Fig. 12 is a contour diagram schematically showing the temperature of air flowing between the heat dissipation fins 12 provided in the semiconductor device 202 according to the modification of the first embodiment.

[0034] Furthermore, if it is desired to reduce the temperature reached by the heat sink-integrated semiconductor module 100 on the most downwind side, structural support members 23 are arranged between the heat sinks 13 of adjacent heat sink-integrated semiconductor modules 100 arranged on the most downwind side, and between the housing 20 and the heat sink 13 of the heat sink-integrated semiconductor module 100 arranged on the most downwind side, as shown in Figures 10 and 11.

[0035] By arranging the structural support members 23 around the heat sink-integrated semiconductor module 100 arranged on the most downwind side, the flow rate of air flowing between the heat dissipation fins 12 of the heat sink-integrated semiconductor module 100 arranged on the most downwind side is further increased. As a result, the heat dissipation performance of the heat sink 13 is further improved, and as shown in FIG. 12 , it is possible to further reduce the temperature reached by the heat sink-integrated semiconductor module 100 arranged on the most downwind side.

[0036] Furthermore, by adding the structural support member 23, it is possible to suppress bending of the mounting plate 21 to which the heatsink-integrated semiconductor modules 100, 100A, 100B are attached. If the mounting plate 21 bends, not only will it become impossible to secure the housing 20 and the mounting plate 21 together, but the stress on each part due to vibrations during product use will increase, which may increase the rate of product failure. However, it is possible to avoid these problems.

[0037] (Manufacturing Method) Next, a method for manufacturing the semiconductor device 202 will be described. Fig. 13 is a cross-sectional view showing a method for manufacturing the heatsink-integrated semiconductor module 100B included in the semiconductor device 202 according to the first embodiment. Fig. 14 is a cross-sectional view showing a method for manufacturing the heatsink-integrated semiconductor module 100 included in the semiconductor device according to the first embodiment. Since the manufacturing method for the heatsink-integrated semiconductor modules 100, 100A, and 100B is the same, only the manufacturing method for the heatsink-integrated semiconductor modules 100 and 100B will be described here.

[0038] As shown in Figures 13 and 14, a semiconductor module 10 is formed in which a semiconductor element 1 is mounted on a fin base 9 and the semiconductor element 1 is sealed with a sealing material 7 in such a manner that the first uneven portion 9a of the fin base 9 opposite the side on which the semiconductor element 1 is mounted is exposed.

[0039] Next, a heat sink 13 is prepared in which a second uneven portion 11a that fits into the first uneven portion 9a is formed on the heat sink base 11, and a plurality of heat dissipation fins 12 are integrated with the heat sink base 11 by crimping on the side opposite to the second uneven portion 11a. Furthermore, a crimping blade unit 30 is prepared as a jig having a plurality of crimping blades that are inserted between the plurality of heat dissipation fins 12 of the heat sink 13 and receive a press load.

[0040] Next, after mounting the heat sink 13 on the crimping blade unit 30, the semiconductor module 10, which has been integrated with the sealing material 7 with the first uneven portion 9a of the fin base 9 exposed, is set on the second uneven portion 11a of the heat sink 13 and a press load is applied, thereby integrating the fin base 9 of the semiconductor module 10 and the heat sink 13.

[0041] By adopting this manufacturing method, the crimping blade unit 30 only needs to support the area of ​​the heat sink 13 that corresponds to the semiconductor module 10, so even if the dimensions of the heat sink base 11 of the heat sink 13 increase and the number of heat dissipation fins 12 increases, the same crimping blade unit 30 can be used. Therefore, it is possible to reduce the temperature reached by the heat sink-integrated semiconductor module 100 located on the most downwind side without reducing productivity.

[0042] Finally, although not shown, the mounting plate 21 is fixed to the housing 20, and then the heat sink-integrated semiconductor modules 100, 100A, 100B are mounted and fixed on the mounting plate 21. In this way, the semiconductor device 202 is completed.

[0043] (Effect) As described above, the semiconductor device 202 according to the first embodiment includes a housing 20, a mounting plate 21 fixed within the housing 20 and having a plurality of openings, a plurality of heat sinks 13 attached to the plurality of openings of the mounting plate 21, a plurality of semiconductor modules 10 mounted on the plurality of heat sinks 13, and a cooling fan 22 provided in the housing 20 and sending air to the plurality of heat sinks 13. The plurality of heat sinks 13 are arranged along a first direction parallel to the airflow direction of the cooling fan 22, and the dimension in a second direction orthogonal to the first direction of the heat sink 13 arranged on the windward side of the plurality of heat sinks 13 is smaller than the dimension in the second direction of the heat sink 13 arranged on the downwind side.

[0044] Each of the semiconductor modules 10 is a heat sink integrated semiconductor module 100, 100A, or 100B that is integrally configured with a corresponding heat sink 13.

[0045] The heat sinks 13 are arranged in two rows along the first direction, and the central axes 31 of the heat sinks 13 in each row are aligned in the first direction.

[0046] Therefore, air with a small temperature rise that passes through the space on the upwind side where the heat sink 13 is not disposed, more specifically the space where the heat dissipation fins 12 are not disposed, flows into the heat sink 13 disposed on the downwind side, thereby reducing the temperature reached by the semiconductor module 10 mounted on the heat sink 13 disposed on the downwind side. This makes it possible to reduce the temperature reached by the heat sink-integrated semiconductor module 100 disposed on the most downwind side and to make the heat sink 13 smaller.

[0047] Furthermore, varying the dimension of the heat sink 13 in the second direction between the upwind side and the downwind side is equivalent to varying the dimension of the heat sink 13 in the second direction for each of the U-phase, V-phase, and W-phase of the semiconductor device. Therefore, by visually checking the heat sink 13, it is easy to recognize in which phase the heat sink-integrated semiconductor module 100, 100A, 100B has been used or is scheduled to be used. This improves the productivity and workability of the semiconductor device.

[0048] Furthermore, structural support members 23 are provided between adjacent heat sinks 13 located on the most downwind side, and between the housing 20 and the heat sink 13 located on the most downwind side. This makes it possible to further reduce the temperature reached by the heat sink-integrated semiconductor module 100 located on the most downwind side. Also, it is possible to suppress deflection of the mounting plate 21 to which the heat sink-integrated semiconductor modules 100, 100A, 100B are attached.

[0049] Furthermore, the heat sink integrated semiconductor modules 100, 100A, and 100B do not use thermal conductive grease, and therefore have low thermal resistance and excellent long-term reliability.

[0050] Second Embodiment Next, a semiconductor device 202 according to a second embodiment will be described. Fig. 15 is a top view of the semiconductor device 202 according to the second embodiment. Fig. 16 is a bottom view of the semiconductor device 202 according to the second embodiment. Fig. 17 is a contour diagram schematically showing the temperature of air flowing between the heat dissipation fins 12 provided in the semiconductor device 202 according to the second embodiment. Note that in the second embodiment, the same components as those described in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0051] In the first embodiment, the central axes 31 in the first direction of the heat sinks 13 in each row are aligned, whereas in the second embodiment, the central axes 31 in the first direction of at least one heat sink 13 in each row are misaligned, as shown in Fig. 15. In Fig. 15, the two heat sink-integrated semiconductor modules 100A, 100B are arranged such that the central axes 31 in the first direction of the heat sinks 13 of the two heat sink-integrated semiconductor modules 100A, 100B are misaligned with the central axis 31 in the first direction of the heat sink-integrated semiconductor module 100 in each row.

[0052] Heat generated by the multiple semiconductor elements 1 mounted on the heat sink-integrated semiconductor modules 100, 100A, and 100B is transferred through the bonding material 2, the metal conductor 4, the insulating material 5, and the fin base 9, and is then dissipated from the heat dissipation fins 12. For this reason, the temperature is highest near the center of the fin base 9 in the second direction, and the temperature of the air flowing between the heat dissipation fins 12 is also high near the center of the fin base 9 in the second direction. However, by making the temperature of the air flowing between the heat dissipation fins 12 near the center of the fin base 9 in the second direction air that increases in temperature less, the temperature reached by the heat sink-integrated semiconductor module 100 arranged on the downwind side can be reduced.

[0053] As shown in Figures 15 to 17, in embodiment 2, the central axis 31 in the second direction of the heatsink-integrated semiconductor modules 100, 100A, and 100B is shifted by at least one position, thereby reducing the temperature of the air flowing into the heat dissipation fins 12 and reducing the temperature reached by the heatsink-integrated semiconductor module 100 located on the most downwind side.

[0054] Next, a description will be given of a modification of the second embodiment. Fig. 18 is a bottom view of a semiconductor device 202 according to the modification of the second embodiment.

[0055] As shown in Figure 18, as in embodiment 1, structural support members 23 may be arranged between the heat sinks 13 of adjacent heat sink-integrated semiconductor modules 100 arranged on the most downwind side, and between the housing 20 and the heat sink 13 of the heat sink-integrated semiconductor module 100 arranged on the most downwind side.

[0056] This makes it possible to further reduce the temperature reached by the heat sink-integrated semiconductor module 100 arranged on the most downwind side. Also, it is possible to suppress bending of the mounting plate 21 to which the heat sink-integrated semiconductor modules 100, 100A, 100B are attached.

[0057] (Effect) As described above, in the semiconductor device 202 according to the second embodiment, the plurality of heat sinks 13 are arranged in two rows along the first direction, and the central axis 31 in the first direction of at least one heat sink 13 in each row is offset.

[0058] Therefore, the temperature of the air flowing into the heat dissipation fins 12 is reduced, and the temperature reached by the semiconductor module 10 mounted on the heat sink 13 arranged on the downwind side is reduced. This makes it possible to reduce the temperature reached by the heat sink-integrated semiconductor module 100 arranged on the most downwind side and to make the heat sink 13 smaller.

[0059] Furthermore, structural support members 23 are provided between adjacent heat sinks 13 located on the most downwind side, and between the housing 20 and the heat sink 13 located on the most downwind side. This makes it possible to further reduce the temperature reached by the heat sink-integrated semiconductor module 100 located on the most downwind side. Also, it is possible to suppress deflection of the mounting plate 21 to which the heat sink-integrated semiconductor modules 100, 100A, 100B are attached.

[0060] Third Embodiment Next, a semiconductor device 202 according to a third embodiment will be described. Fig. 19 is a top view of the semiconductor device 202 according to the third embodiment. Fig. 20 is a cross-sectional view taken along line A-A in Fig. 19. Note that in the third embodiment, the same components as those described in the first and second embodiments are denoted by the same reference numerals, and description thereof will be omitted.

[0061] In the first and second embodiments, the dimension in the second direction of the heat sink 13 arranged on the windward side among the plurality of heat sinks 13 is smaller than the dimension in the second direction of the heat sink 13 arranged on the downwind side. In contrast, in the third embodiment, as shown in Fig. 19, the dimension in the first direction of the heat sink 13 arranged on the windward side among the plurality of heat sinks 13 is smaller than the dimension in the first direction of the heat sink 13 arranged on the downwind side.

[0062] More specifically, the first-direction dimension of the heat sink 13 of the heat sink-integrated semiconductor module 100D arranged on the upwind side is smaller than the first-direction dimension of the heat sink 13 of the heat sink-integrated semiconductor module 100C arranged on the downwind side. The first-direction dimension of the heat sink 13 of the heat sink-integrated semiconductor module 100C arranged on the upwind side is also smaller than the first-direction dimension of the heat sink 13 of the heat sink-integrated semiconductor module 100 arranged on the downwind side. In other words, the first-direction dimension of the heat sink 13 decreases from the downwind side to the upwind side. The second-direction dimension of the heat sink 13 of the heat sink-integrated semiconductor modules 100, 100C, and 100D is the same. The manufacturing method for the heat sink-integrated semiconductor modules 100C and 100D is the same as the manufacturing method for the heat sink-integrated semiconductor modules 100, 100A, and 100B, and therefore will not be described here.

[0063] As described above, the dimension in the first direction of the heat sink 13 arranged on the upwind side is smaller than the dimension in the first direction of the heat sink 13 arranged on the downwind side, so that air with a small temperature rise that passes through the portion on the upwind side where there are no heat dissipation fins 12 flows between the heat dissipation fins 12 of the heat sink 13 arranged on the downwind side. As a result, it is possible to reduce the average temperature of the air flowing between the heat dissipation fins 12 compared to a conventional configuration in which all heat sinks 13 have the same dimensions. Therefore, it is possible to reduce the temperature reached by the heat sink-integrated semiconductor module 100 arranged on the most downwind side compared to the conventional configuration described above.

[0064] In addition, in order to reduce the temperature reached by the heat sink-integrated semiconductor module 100 located on the most downwind side, the heat dissipation fins 12 of the heat sink-integrated semiconductor modules 100C, 100D other than the heat sink-integrated semiconductor module 100 located on the most downwind side may be thinned out, as shown in Figure 20.

[0065] Also, although not shown, as in embodiments 1 and 2, structural support members 23 may be arranged between the heat sinks 13 of adjacent heat sink-integrated semiconductor modules 100 arranged on the most downwind side, and between the housing 20 and the heat sink 13 of the heat sink-integrated semiconductor module 100 arranged on the most downwind side.

[0066] (Effect) As described above, the semiconductor device 202 according to the third embodiment includes the housing 20, the mounting plate 21 fixed inside the housing 20 and having a plurality of openings, a plurality of heat sinks 13 attached to the plurality of openings of the mounting plate 21, a plurality of semiconductor modules 10 mounted on the plurality of heat sinks 13, and the cooling fan 22 provided in the housing 20 and sending air to the plurality of heat sinks 13. The plurality of heat sinks 13 are arranged along a first direction parallel to the airflow direction of the cooling fan 22, and the dimension in the first direction of the heat sink 13 arranged on the upwind side of the plurality of heat sinks 13 is smaller than the dimension in the first direction of the heat sink 13 arranged on the downwind side.

[0067] The semiconductor modules 10 are heat sink-integrated semiconductor modules 100, 100C, and 100D that are integrally formed with the heat sinks 13, respectively.

[0068] Therefore, air with a small temperature rise that passes through the space where the heat sink 13 arranged on the windward side is not arranged, more specifically the space where the heat dissipation fins 12 are not arranged, flows into the heat sink 13 arranged on the downwind side, thereby reducing the temperature reached by the semiconductor module 10 mounted on the heat sink 13 arranged on the most downwind side. This makes it possible to reduce the temperature reached by the heat sink-integrated semiconductor module 100 arranged on the most downwind side and to make the heat sink 13 smaller.

[0069] Furthermore, structural support members 23 are provided between adjacent heat sinks 13 located on the most downwind side, and between the housing 20 and the heat sink 13 located on the most downwind side. This makes it possible to further reduce the temperature reached by the heat sink-integrated semiconductor module 100 located on the most downwind side. Also, it is possible to suppress deflection of the mounting plate 21 to which the heat sink-integrated semiconductor modules 100, 100C, and 100D are attached.

[0070] Fourth Embodiment In this embodiment, the semiconductor device 202 according to the above-described first to third embodiments is applied to a power conversion device. Although the application of the semiconductor device 202 according to the first to third embodiments is not limited to a specific power conversion device, the following will describe a case where the semiconductor device 202 according to the first to third embodiments is applied to a three-phase inverter as the fourth embodiment.

[0071] FIG. 21 is a block diagram showing the configuration of a power conversion system to which the power conversion device according to this embodiment is applied.

[0072] The power conversion system shown in Fig. 21 is composed of a power supply 150, a power conversion device 200, and a load 300. The power supply 150 is a DC power supply and supplies DC power to the power conversion device 200. The power supply 150 can be composed of various components, such as a DC system, a solar cell, or a storage battery, or it may be composed of a rectifier circuit connected to an AC system or an AC / DC converter. The power supply 150 may also be composed of a DC / DC converter that converts DC power output from a DC system into a predetermined power.

[0073] The power conversion device 200 is a three-phase inverter connected between the power supply 150 and the load 300, and converts DC power supplied from the power supply 150 into AC power and supplies the AC power to the load 300. As shown in Fig. 21 , 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.

[0074] 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.

[0075] The power conversion device 200 will be described in detail below. The main conversion circuit 201 includes switching elements (not shown) and freewheeling diodes (not shown). The switching elements convert DC power supplied from the power supply 150 into AC power, which is supplied to the load 300. While the main conversion circuit 201 can have a variety of specific circuit configurations, 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 freewheeling diodes connected in anti-parallel to each switching element. The semiconductor device 202 according to any one of the first to third embodiments described above is applied to at least one of the switching elements and freewheeling diodes of the main conversion circuit 201. Two of the six switching elements are connected in series to form upper and lower arms, which form each phase (U phase, V phase, and 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.

[0076] The main conversion circuit 201 also includes a drive circuit (not shown) that drives each switching element. The drive circuit may be built into the semiconductor device 202, or may be provided separately from the semiconductor device 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. To maintain 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 to maintain 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.

[0077] 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. The control circuit 203 then outputs a control command (control signal) to a drive circuit included 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.

[0078] In the power conversion device according to this embodiment, the semiconductor device 202 according to the first to third embodiments is used as the switching element and free wheel diode of the main conversion circuit 201, so that miniaturization can be achieved.

[0079] In the present embodiment, an example has been described in which the semiconductor device 202 according to the first to third embodiments is applied to a two-level three-phase inverter, but the application of the semiconductor device 202 according to the first to third embodiments is not limited to this, and the semiconductor device 202 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 semiconductor device 202 according to the first to third embodiments may also be applied to a single-phase inverter. Furthermore, when power is supplied to a DC load or the like, the semiconductor device 202 according to the first to third embodiments can also be applied to a DC / DC converter or an AC / DC converter.

[0080] Furthermore, the power conversion device to which the semiconductor device 202 according to any one of the first to third embodiments is applied is not limited to the case where the load described above 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, or the like.

[0081] Although the present disclosure has been described in detail, the above description is illustrative in all respects and is not restrictive. It is understood that countless variations not illustrated can be envisioned.

[0082] It should be noted that the embodiments can be freely combined, and each embodiment can be modified or omitted as appropriate.

[0083] Various aspects of the present disclosure are summarized below as appendices.

[0084] (Supplementary Note 1) A semiconductor device comprising: a housing; a mounting plate fixed within the housing and having a plurality of openings; a plurality of heat sinks attached to the plurality of openings of the mounting plate, respectively; a plurality of semiconductor modules mounted on the plurality of heat sinks, respectively; and a cooling fan provided in the housing and sending air to the plurality of heat sinks, wherein the plurality of heat sinks are arranged along a first direction parallel to the airflow direction of the cooling fan, and a dimension in a second direction perpendicular to the first direction of the heat sink arranged on the upwind side of the plurality of heat sinks is smaller than a dimension in the second direction of the heat sink arranged on the downwind side.

[0085] (Supplementary Note 2) The semiconductor device according to Supplementary Note 1, wherein the heat sinks are arranged in two rows along the first direction, and the central axes of the heat sinks in each row in the first direction are aligned.

[0086] (Supplementary Note 3) The semiconductor device according to Supplementary Note 1, wherein the plurality of heat sinks are arranged in two rows along the first direction, and the central axes of at least one of the heat sinks in each row in the first direction are offset from each other.

[0087] (Supplementary Note 4) The semiconductor device according to Supplementary Note 2, wherein structural support members are provided between adjacent heat sinks arranged on the most downwind side, and between the housing and the heat sink arranged on the most downwind side.

[0088] (Supplementary Note 5) The semiconductor device according to Supplementary Note 3, wherein structural support members are provided between adjacent heat sinks arranged on the most downwind side, and between the housing and the heat sink arranged on the most downwind side.

[0089] (Appendix 6) A semiconductor device comprising: a housing; a mounting plate fixed within the housing and having a plurality of openings; a plurality of heat sinks respectively attached to the plurality of openings of the mounting plate; a plurality of semiconductor modules respectively mounted on the plurality of heat sinks; and a cooling fan provided in the housing and sending air to the plurality of heat sinks, wherein the plurality of heat sinks are arranged along a first direction parallel to the airflow direction of the cooling fan, and the dimension in the first direction of the heat sink arranged on the upwind side of the plurality of heat sinks is smaller than the dimension in the first direction of the heat sink arranged on the downwind side.

[0090] (Appendix 7) The semiconductor device described in Appendix 6, wherein the plurality of heat sinks are arranged in two rows along the first direction, and structural support members are provided between adjacent heat sinks arranged on the most downwind side, and between the housing and the heat sink arranged on the most downwind side.

[0091] (Supplementary Note 8) The semiconductor device according to any one of Supplementary Note 1 to Supplementary Note 7, wherein each of the semiconductor modules is a heat sink integrated semiconductor module configured integrally with each of the heat sinks.

[0092] (Appendix 9) A method for manufacturing a semiconductor device, comprising: a step of forming a semiconductor module in which a semiconductor element is mounted on a fin base and the semiconductor element is sealed with a sealing material in a manner that a first uneven portion of the fin base opposite to the side on which the semiconductor element is mounted is exposed; a step of preparing a heat sink in which a second uneven portion that fits with the first uneven portion is formed in the heat sink base and a plurality of heat dissipation fins are integrated with the heat sink base on the side opposite to the second uneven portion; a step of mounting the heat sink on a jig that is inserted between the plurality of heat dissipation fins of the heat sink and that receives a press load; a step of integrating the fin base and the heat sink; a step of fixing a mounting plate to a housing; and a step of mounting and fixing the semiconductor module integrated with the heat sink to the mounting plate.

[0093] (Supplementary Note 10) A power conversion device comprising: a main conversion circuit having the semiconductor device according to any one of Supplementary Note 1 to Supplementary Note 8, which converts input power and outputs the converted power; and a control circuit which outputs a control signal for controlling the main conversion circuit to the main conversion circuit.

[0094] REFERENCE SIGNS LIST 1 Semiconductor element, 7 Sealing material, 9 Fin base, 9a First uneven portion, 10 Semiconductor module, 11 Heat sink base, 11a Second uneven portion, 12 Heat dissipation fin, 13 Heat sink, 20 Housing, 21 Mounting plate, 22 Cooling fan, 23 Structural support member, 100, 100A, 100B, 100C, 100D Heat sink integrated semiconductor module, 200 Power conversion device, 201 Main conversion circuit, 202 Semiconductor device, 203 Control circuit.

Claims

1. A semiconductor device comprising: a housing; a mounting plate fixed within the housing and having a plurality of openings; a plurality of heat sinks respectively attached to the plurality of openings of the mounting plate; a plurality of semiconductor modules respectively mounted on the plurality of heat sinks; and a cooling fan provided in the housing for blowing air to the plurality of heat sinks, wherein the plurality of heat sinks are arranged along a first direction parallel to the blowing direction of the cooling fan, and a dimension in a second direction perpendicular to the first direction of the heat sink arranged on the windward side of the plurality of heat sinks is smaller than the dimension in the second direction of the heat sink arranged on the downwind side.

2. The semiconductor device according to claim 1, wherein the heat sinks are arranged in two rows along the first direction, and the central axes of the heat sinks in each row in the first direction are aligned.

3. The semiconductor device according to claim 1, wherein the heat sinks are arranged in two rows along the first direction, and the central axes of at least one of the heat sinks in each row are offset from one another in the first direction.

4. The semiconductor device according to claim 2, further comprising structural support members provided between adjacent heat sinks located on the most downwind side and between the housing and the heat sink located on the most downwind side.

5. The semiconductor device according to claim 3, further comprising structural support members provided between adjacent heat sinks located on the most downwind side, and between the housing and the heat sink located on the most downwind side.

6. A semiconductor device comprising: a housing; a mounting plate fixed within the housing and having a plurality of openings; a plurality of heat sinks respectively attached to the plurality of openings of the mounting plate; a plurality of semiconductor modules respectively mounted on the plurality of heat sinks; and a cooling fan provided in the housing for blowing air to the plurality of heat sinks, wherein the plurality of heat sinks are arranged along a first direction parallel to the blowing direction of the cooling fan, and the dimension in the first direction of the heat sink arranged on the windward side of the plurality of heat sinks is smaller than the dimension in the first direction of the heat sink arranged on the downwind side.

7. The semiconductor device described in claim 6, wherein the heat sinks are arranged in two rows along the first direction, and structural support members are provided between adjacent heat sinks arranged on the most downwind side, and between the housing and the heat sink arranged on the most downwind side.

8. The semiconductor device according to any one of claims 1 to 7, wherein each of the semiconductor modules is a heat sink integrated semiconductor module that is integrally configured with each of the heat sinks.

9. A method for manufacturing a semiconductor device, comprising the steps of: mounting a semiconductor element on a fin base, and forming a semiconductor module in which the semiconductor element is sealed with a sealing material in a manner that exposes a first uneven portion of the fin base opposite the side on which the semiconductor element is mounted; preparing a heat sink in which a second uneven portion that fits into the first uneven portion is formed in a heat sink base, and a plurality of heat dissipation fins are integrated with the heat sink base on the opposite side to the second uneven portion; mounting the heat sink on a jig that is inserted between the plurality of heat dissipation fins of the heat sink and receives a press load; integrating the fin base and the heat sink; fixing a mounting plate to a housing; and mounting and fixing the semiconductor module integrated with the heat sink to the mounting plate.

10. A power conversion device comprising: a main conversion circuit having a semiconductor device according to any one of claims 1 to 8, which converts input power and outputs it; and a control circuit which outputs a control signal for controlling said main conversion circuit to said main conversion circuit.

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