Semiconductor device and power conversion device

Abstract

A cooler (3) has a first main surface (31). A bonding material (7) is provided on the first main surface (31). In the first main surface (31), a groove (90) is provided. When viewed in a first direction (101) from the bonding material (7) toward the first main surface (31), a part of the groove (90) is provided between a fastening part (5) and the bonding material (7). The cooler (3) has a fastened region (50). In a second direction (102), in which the distance from the fastened region (50) to the bonding material (7) is shortest, a first distance (D1) is shorter than a second distance (D2), where the first distance (D1) is the distance between the groove (90) and the bonding material (7) and the second distance (D2) is the distance between the fastened region (50) and the groove (90).

Description

Semiconductor device and power conversion device

[0001] The present disclosure relates to a semiconductor device and a power conversion device.

[0002] As an example of a semiconductor device, Japanese Patent Laid-Open Publication No. 2012-142465 (Patent Document 1) describes a semiconductor device including a semiconductor module having a metal plate exposed on one surface of a sealing body, and a heat dissipation member bonded to the exposed surface of the metal plate via a bonding material. In this semiconductor device, the exposed metal plate in the semiconductor module is bonded to a cooling device with the bonding material. The metal plate has a bonded region where the metal plate is bonded and a non-bonded region where the metal plate is not bonded. The semiconductor device also includes a resin agent. The resin agent is provided in the non-bonded region, a peripheral region of the bonding material, and a peripheral bonded region around the bonded portion of the cooling device.

[0003] JP 2012-142465 A

[0004] In the semiconductor module described in Patent Document 1, deformation of the cooler that occurs when the cooler and the jacket are fastened together can cause the resin agent to peel off from the cooling device. As a result, the resin agent is no longer able to prevent deterioration of the bonding material. As a result, the reliability of the semiconductor device is reduced.

[0005] The present disclosure has been made in view of the above, and has an object to provide a semiconductor device and a power conversion device that can improve reliability.

[0006] The semiconductor device according to the present disclosure comprises a cooler, a bonding material, a first semiconductor module, and a fastening portion. The cooler has a first main surface. The bonding material is provided on the first main surface. The first semiconductor module is provided on the bonding material. The fastening portion fastens the cooler to the jacket portion. A groove is provided in the first main surface. When viewed in a first direction from the bonding material toward the first main surface, a portion of the groove is provided between the fastening portion and the bonding material. The cooler has a fastened region. The fastened region is constituted by a region of the cooler that is in contact with the fastening portion. In a second direction from the fastened region toward the bonding material in the shortest direction, the distance between the groove and the bonding material is defined as a first distance, and the distance between the fastened region and the groove is defined as a second distance, the first distance is shorter than the second distance.

[0007] According to the semiconductor device of the present disclosure, deformation of the portion of the cooler that is in contact with the bonding material can be suppressed when the cooler and the jacket portion are fastened together, thereby providing a semiconductor device and a power conversion device that can improve reliability.

[0008] 5 is a cross-sectional view schematically illustrating a configuration of a semiconductor device according to a first embodiment; FIG. 6 is a first plan view schematic illustrating a configuration of a semiconductor device according to the first embodiment; FIG. 7 is a second plan view schematic illustrating a configuration of a semiconductor device according to the first embodiment; FIG. 8 is an enlarged schematic view showing a region IV of FIG. 1; FIG. 9 is a cross-sectional view schematic illustrating a configuration of a semiconductor device according to a comparative example; FIG. 11 is an enlarged schematic view showing a region VI of FIG. 5; FIG. 9 is a cross-sectional view schematic illustrating a state in which a crack has occurred in a bonding material; FIG. 12 is a cross-sectional view schematic illustrating a configuration of a semiconductor device according to a modification of the first embodiment; FIG. 13 is a cross-sectional view schematic illustrating a configuration of a semiconductor device according to a second embodiment; FIG. 14 is a cross-sectional view schematic illustrating a configuration of a semiconductor device according to a third embodiment; FIG. 15 is a cross-sectional view schematic illustrating a configuration of a semiconductor device according to a modification of the third embodiment; FIG. 16 is a cross-sectional view schematic illustrating a configuration of a semiconductor device according to a fourth embodiment; FIG. 17 is a cross-sectional view schematic illustrating a configuration of a semiconductor device according to a fifth embodiment; FIG. 18 is a cross-sectional view schematic illustrating a configuration of a semiconductor device according to a fifth embodiment; FIG. 19 is a cross-sectional view schematic illustrating a configuration of a semiconductor device according to a first modification of the fifth embodiment; FIG. 19 is a cross-sectional view schematic illustrating a configuration of a semiconductor device according to a second ... sixth embodiment; Fig. 13 is a schematic cross-sectional view showing the configuration of a semiconductor device according to a seventh embodiment. Fig. 14 is a schematic plan view showing the configuration of a semiconductor device according to the seventh embodiment. Fig. 15 is a schematic cross-sectional view showing the configuration of a semiconductor device according to an eighth embodiment. Fig. 16 is a schematic bottom view showing the configuration of a cooler according to the eighth embodiment. Fig. 17 is a block diagram showing the configuration of a power conversion system to which a power conversion device according to an eleventh embodiment is applied.

[0009] Hereinafter, embodiments of the present disclosure 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.

[0010] First Embodiment First, an example of the configuration of a semiconductor device 10 according to a first embodiment will be shown with reference to Figures 1 and 2. As shown in Figure 1, the semiconductor device 10 mainly includes a first semiconductor module 1, a cooler 3, a bonding material 7, a jacket portion 4, a fastening portion 5, and an elastic body 6.

[0011] The cooler 3 cools the first semiconductor module 1. The bonding material 7 bonds the first semiconductor module 1 and the cooler 3 together. The jacket portion 4 holds a coolant. The jacket portion 4 is, for example, a water jacket. The fastening portion 5 fastens the cooler 3 and the jacket portion 4 together. The fastening portion 5 is, for example, a male screw. The elastic body 6 seals the gap between the jacket portion 4 and the cooler 3. The elastic body 6 is, for example, rubber. The elastic body 6 is, for example, an O-ring.

[0012] The cooler 3 is made of, for example, aluminum or copper. The cooler 3 is manufactured by forging, for example. The cooler 3 has a plate portion 8 and a plurality of heat dissipation portions 9. The plate portion 8 has a first main surface 31 and a second main surface 32. The second main surface 32 is opposite the first main surface 31. The plurality of heat dissipation portions 9 are connected to the plate portion 8 at the second main surface 32. Each of the plurality of heat dissipation portions 9 has, for example, a pin-like shape. Specifically, each of the plurality of heat dissipation portions 9 has, for example, a cylindrical shape. Each of the plurality of heat dissipation portions 9 extends in a direction perpendicular to the second main surface 32. Specifically, the extension direction of each of the plurality of heat dissipation portions 9 is perpendicular to the portion of the second main surface 32 to which each of the plurality of heat dissipation portions 9 is connected.

[0013] The bonding material 7 is provided on the first main surface 31. The direction from the bonding material 7 toward the first main surface 31 is defined as a first direction 101. The bonding material 7 is provided between the cooler 3 and the first semiconductor module 1. The bonding material 7 transfers heat generated in the first semiconductor module 1 to the cooler 3. The bonding material 7 is made of, for example, solder. The bonding material 7 may also be made of, for example, a highly thermally conductive adhesive or sintered silver.

[0014] The first semiconductor module 1 is provided on a bonding material 7. The first semiconductor module 1 has an insulating substrate 30, a first semiconductor element 13, a second semiconductor element 14, a sealing material 20, a first terminal 18, a second terminal 19, a first inner bonding material 21, a second inner bonding material 22, a third inner bonding material 23, a fourth inner bonding material 24, and wiring 25.

[0015] The insulating substrate 30 is provided on the bonding material 7. The insulating substrate 30 has an insulating layer 15, a first conductor pattern 11, and a second conductor pattern 12. The insulating layer 15 is made of, for example, ceramic. The insulating layer 15 has a first surface 16 and a second surface 17. The second surface 17 is opposite the first surface 16.

[0016] The first conductor pattern 11 is provided on the first surface 16. The first conductor pattern 11 is bonded to the cooler 3 by a bonding material 7. The bonding material 7 is provided between the cooler 3 and the first conductor pattern 11. The second conductor pattern 12 is provided on the second surface 17.

[0017] The first internal bonding material 21 is provided on the second conductor pattern 12. The first internal bonding material 21 bonds the second conductor pattern 12 and the first semiconductor element 13. The first semiconductor element 13 is electrically connected to the second conductor pattern 12. Specifically, the first semiconductor element 13 is electrically connected to the second conductor pattern 12 via the first internal bonding material 21.

[0018] The second internal bonding material 22 is provided on the second conductor pattern 12. The second internal bonding material 22 bonds the second conductor pattern 12 and the second semiconductor element 14. The second semiconductor element 14 is electrically connected to the second conductor pattern 12. Each of the first semiconductor element 13 and the second semiconductor element 14 is a power semiconductor element, such as a transistor, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), or an IGBT (Insulated Gate Bipolar Transistor). Hereinafter, the first semiconductor element 13 and the second semiconductor element 14 will also be simply referred to as semiconductor elements.

[0019] The sealing material 20 seals the first semiconductor element 13, the second semiconductor element 14, and the insulating substrate 30. Specifically, the sealing material 20 covers the insulating layer 15, the second conductor pattern 12, the first semiconductor element 13, and the second semiconductor element 14. The sealing material 20 covers a portion of the first conductor pattern 11. From another perspective, a portion of the first conductor pattern 11 is exposed from the sealing material 20. The portion of the first conductor pattern 11 exposed from the sealing material 20 is in contact with the bonding material 7. The sealing material 20 is made of a resin material such as epoxy. The linear expansion coefficient of the sealing material 20 is smaller than that of the cooler 3, for example. Specifically, the linear expansion coefficient of the material constituting the sealing material 20 is smaller than that of the material constituting the cooler 3.

[0020] A portion of the first terminal 18 is covered with the sealing material 20. From another perspective, a portion of the first terminal 18 is exposed from the sealing material 20. The portion of the first terminal 18 covered with the sealing material 20 is electrically connected to the first semiconductor element 13 by a wiring 25.

[0021] A portion of the second terminal 19 is covered with the sealing material 20. From another perspective, a portion of the second terminal 19 is exposed from the sealing material 20. The portion of the second terminal 19 covered with the sealing material 20 is electrically connected to the first semiconductor element 13 by a third inner bonding material 23. The portion of the second terminal 19 covered with the sealing material 20 is electrically connected to the second semiconductor element 14 by a fourth inner bonding material 24.

[0022] Each of the first inner bonding material 21, the second inner bonding material 22, the third inner bonding material 23, and the fourth inner bonding material 24 is made of solder, silver, or the like. The wiring 25 is, for example, an aluminum wire. The surface of the first terminal 18 may be plated with nickel (Ni), tin (Sn), or the like. Similarly, the surface of the second terminal 19 may be plated with nickel, tin, or the like.

[0023] Fig. 2 shows the configuration of the cooler 3 and the bonding material 7 as viewed in the first direction 101. In other words, the first semiconductor module 1 and the fastening portion 5 are not shown in Fig. 2. As shown in Fig. 2, the cooler 3 has a fastening region 50. The fastening region 50 is formed by a region of the cooler 3 that is in contact with the fastening portion 5 (see Fig. 1). The fastening region 50 is, for example, a part of the first main surface 31.

[0024] The fastened region 50 has four first portions 51. The four first portions 51 are spaced apart from one another. The four first portions 51 are regions of the cooler 3 that are in contact with four different fastening portions 5 (see FIG. 1 ). In FIG. 2 , a rectangle 98 is shown that connects the four first portions 51. When viewed in the first direction 101, the rectangle 98 is formed by connecting the centers of the first portions 51.

[0025] A groove 90 is provided in the first main surface 31. When viewed in the first direction 101, the groove 90 is, for example, annular. When viewed in the first direction 101, the groove 90 surrounds, for example, the bonding material 7. When viewed in the first direction 101, the groove 90 is provided inside a quadrangle 98. From another perspective, when viewed in the first direction 101, the outer edge of the quadrangle 98 is spaced apart from the groove 90. The groove 90 has, for example, a first groove portion 91 and a third groove portion 93.

[0026] When viewed in the first direction 101, the first groove portion 91 is provided between the fastening portion 5 and the bonding material 7. Specifically, the first groove portion 91 is provided between at least one fastening portion 5 and the bonding material 7. When viewed in the first direction 101, the shape of the first groove portion 91 is, for example, a C-shape.

[0027] As viewed in the first direction 101, the third groove portion 93 is located opposite the first groove portion 91 with respect to the bonding material 7. From another perspective, as viewed in the first direction 101, the bonding material 7 is provided between the first groove portion 91 and the third groove portion 93. As viewed in the first direction 101, the third groove portion 93 is, for example, linear.

[0028] The shortest direction from the fastening region 50 to the bonding material 7 is defined as the second direction 102. Specifically, the second direction 102 is, for example, the direction from the first portion 51 closest to the bonding material 7 to the bonding material 7. From another perspective, the second direction 102 is the direction in which the shortest line segment 97 connecting a point on the outer edge of the fastening region 50 and a point on the outer edge of the bonding material 7 extends.

[0029] As viewed in the first direction 101, the distance in the second direction 102 between the groove 90 and the bonding material 7 is defined as a first distance D1. As viewed in the first direction 101, the distance in the second direction 102 between the fastening region 50 and the groove 90 is defined as a second distance D2. The first distance D1 is shorter than the second distance D2.

[0030] In Fig. 3 , the dashed-dotted line indicates the portion of the elastic body 6 that is in contact with the cooler 3. From another perspective, in Fig. 3 , the dashed-dotted line indicates the contact surface between the elastic body 6 and the cooler 3. As shown in Fig. 3 , when viewed in the first direction 101, the elastic body 6 is located between the fastening portion 5 and the bonding material 7. When viewed in the first direction 101, the shortest distance in the second direction 102 from the contact surface between the elastic body 6 and the cooler 3 to the groove 90 is set to a third distance D3. The first distance D1 is shorter than the third distance D3. The third distance D3 is shorter than the second distance D2.

[0031] 1 , the plate portion 8 has a first flat plate member 80, a first plate member 81, a third plate member 83, an intermediate portion 86, and an outer peripheral portion 87. The first flat plate member 80 is in contact with the bonding material 7. The first flat plate member 80 forms the side surface of the groove 90. Each of the plurality of heat dissipation portions 9 is connected to the first flat plate member 80, for example.

[0032] The first plate member 81 is continuous with the first flat plate member 80. The first plate member 81 forms the bottom surface of the first groove portion 91. From another perspective, the first plate member 81 is located between the bottom surface of the first groove portion 91 and the second main surface 32. The first plate member 81 is inclined in the first direction 101 with respect to the first flat plate member 80, for example.

[0033] The third plate member 83 is continuous with the first flat plate member 80. The third plate member 83 forms the bottom surface of the third groove portion 93. From another perspective, the third plate member 83 is located between the bottom surface of the third groove portion 93 and the second main surface 32. The third plate member 83 is inclined in the first direction 101 with respect to the first flat plate member 80, for example.

[0034] The intermediate portion 86 is continuous with each of the first groove portion 91 and the third groove portion 93. When viewed in the first direction 101, the intermediate portion 86 surrounds the first flat plate member 80, the first groove portion 91, and the third groove portion 93. The intermediate portion 86 is inclined in the first direction 101 with respect to the first flat plate member 80, for example.

[0035] The outer peripheral portion 87 is continuous with the intermediate portion 86. The outer peripheral portion 87 surrounds the intermediate portion 86. The outer peripheral portion 87 is the portion that comes into contact with the jacket portion 4 and the elastic body 6. The outer peripheral portion 87 has, for example, a flat plate shape. A plurality of fastening holes 99 are provided in the outer peripheral portion 87. The fastening portions 5 are inserted into the fastening holes 99. The outer peripheral portion 87 constitutes the fastened region 50.

[0036] 4 , in a cross section intersecting the first groove 91, the third groove 93, and the first conductor pattern 11, the direction from the first groove 91 to the third groove 93 is defined as a third direction 103. In the third direction 103, the distance between the first groove 91 and the third groove 93 (fourth distance D4) is longer than the length of the first conductor pattern 11 (first length L1). In the third direction 103, the fourth distance D4 is longer than the length of the bonding material 7 (second length L2). The third direction 103 is perpendicular to the extension direction of the third groove 93.

[0037] In this specification, groove depth F is the depth of groove 90 in the thickness direction from first main surface 31 to second main surface 32, that is, the direction along the side surface of groove 90. Groove width E is the width of groove 90 in a direction perpendicular to the direction in which groove 90 extends as viewed in first direction 101. Groove depth F is, for example, smaller than groove width E.

[0038] As shown in FIG. 1, a housing portion 49 is provided in the jacket portion 4. The housing portion 49 holds the cooler 3. A plurality of heat dissipation portions 9 are located in the housing portion 49. The jacket portion 4 has a support surface 41. The support surface 41 is in contact with the second main surface 32 of the cooler 3. For example, a female screw 42 and a holding groove 43 are provided on the support surface 41. A fastening portion 5 is inserted into the female screw 42. An elastic body 6 is located in the holding groove 43. The elastic body 6 is in contact with the second main surface 32 of the cooler 3. Note that the cross-sectional view shown in FIG. 1 is a combined cross-sectional view taken along line II in FIG. 2.

[0039] Next, the effects of the semiconductor device 10 according to the first embodiment will be described. First, the configuration of the semiconductor device 10 according to the comparative example will be described using FIGS. 5 and 6 . As shown in FIG. 5 , the cooler 3 of the semiconductor device 10 according to the comparative example does not have a groove 90. A reaction force is applied to the cooler 3 from the jacket portion 4 due to the fastening force applied to the cooler 3 from the fastening portion 5. Therefore, the cooler 3 is deformed by fastening the cooler 3 to the jacket portion 4. As a result, in the semiconductor device according to the comparative example, the cooler bends in the direction opposite to the first direction 101. Therefore, as shown in FIG. 6 , the deformation of the cooler 3 applies stress to the bonding material 7 in the direction of arrow A. From another perspective, the deformation of the cooler 3 pulls the bonding material 7 between the cooler 3 and the first semiconductor module 1.

[0040] According to the semiconductor device 10 of the first embodiment, the provision of the groove 90 can weaken the rigidity of the portion of the cooler 3 close to the groove 90. As a result, when the cooler 3 is deformed by the tightening force, the portion of the cooler 3 close to the groove 90 deforms preferentially. This suppresses deformation of the portion of the cooler 3 that is in contact with the bonding material 7. This can alleviate stress on the bonding material 7. This can improve the reliability of the semiconductor device 10.

[0041] Furthermore, according to the semiconductor device 10 of the first embodiment, the distance (first distance D1) in the second direction 102 between the groove 90 and the bonding material 7, as viewed in the first direction 101, is shorter than the distance (second distance D2) in the second direction 102 between the fastening region 50 and the groove 90. This allows the length of the portion of the cooler 3 between the fastening portion 5 and the groove 90 to be sufficiently long. As a result, when the cooler 3 deforms due to the application of a fastening force, energy is generated that cannot be absorbed by the deformation of the portion of the cooler 3 near the groove 90. However, this energy can be dissipated by the deformation of the portion of the cooler 3 between the fastening portion 5 and the groove 90. Therefore, deformation of the portion of the cooler 3 in contact with the bonding material 7 can be effectively suppressed. As a result, the reliability of the semiconductor device 10 can be improved.

[0042] In order to prevent leakage of the coolant, an elastic body 6 may be provided between the cooler 3 and the jacket portion 4. In this case, when the cooler 3 and the jacket portion 4 are fastened together, a reaction force is applied from the elastic body 6 to the cooler 3. This reaction force and the reaction force applied to the cooler 3 from the jacket portion 4 cause the cooler 3 to deform.

[0043] According to the semiconductor device 10 of the first embodiment, the distance (first distance D1) in the second direction 102 between the groove 90 and the bonding material 7, as viewed in the first direction 101, is shorter than the shortest distance (third distance D3) in the second direction 102 from the contact surface between the elastic body 6 and the cooler 3 to the groove 90. Therefore, the portion of the cooler 3 between the contact surface and the groove 90 can be made sufficiently long. This increases the energy consumed by deformation of the portion of the cooler 3 between the contact surface and the groove 90 when the cooler 3 is deformed by the reaction force applied from the elastic body 6 to the cooler 3. Therefore, deformation of the portion of the cooler 3 in contact with the bonding material 7 can be effectively suppressed. As a result, the reliability of the semiconductor device 10 can be effectively improved.

[0044] As shown in Figure 7, cracks C may generally occur in the bonding material 7. Furthermore, when the semiconductor device 10 is operating, the cracks C that have occurred in the bonding material 7 may propagate. Typically, the cracks C propagate from the end of the bonding material 7 toward the center of the bonding material 7 in an in-plane direction perpendicular to the first direction 101. If the cracks C propagate to directly below the semiconductor element, the efficiency with which heat generated by the semiconductor element is transferred to the cooler 3 will be excessively reduced. Therefore, if the distance from the end of the bonding material 7 to the semiconductor element in the in-plane direction perpendicular to the first direction 101 (crack tolerance B) is short, the life of the semiconductor device 10 will be shortened.

[0045] According to the semiconductor device 10 of the first embodiment, in the third direction 103 from the first groove 91 to the third groove 93, the distance between the first groove 91 and the third groove 93 (fourth distance D4) is longer than the length of the first conductor pattern 11 (first length L1). Therefore, the length of the bonding material 7 in the third direction 103 can be longer than when the fourth distance D4 is shorter than the first length L1. This makes it possible to increase the crack tolerance B. As a result, the life of the semiconductor device 10 can be extended.

[0046] When the semiconductor device 10 is operating, a difference in the amount of thermal expansion occurs between the semiconductor module and the cooler 3. Specifically, when the semiconductor device 10 is operating, heat generated by the semiconductor element is transferred to the insulating substrate 30, the sealing material 20, the cooler 3, and the like. As a result, when the temperature of each component of the semiconductor device 10 rises, a difference in the amount of thermal expansion occurs between the components due to the difference in the linear expansion coefficient of each component. When a difference in the amount of thermal expansion occurs between the semiconductor module and the cooler 3, stress resulting from the difference in the amount of thermal expansion is applied to the bonding material 7.

[0047] According to the semiconductor device 10 of the first embodiment, a groove 90 is provided in the first main surface 31 of the cooler 3. Therefore, when a difference in the amount of thermal expansion occurs between the semiconductor module and the cooler 3, the portion of the cooler 3 close to the groove 90 deforms preferentially. This reduces the difference in the amount of deformation between the bonding material 7 and the cooler 3 around the bonding material 7. Therefore, it is possible to alleviate the stress on the bonding material 7 caused by the difference in the amount of thermal expansion. As a result, it is possible to effectively improve the reliability of the semiconductor device 10.

[0048] According to the semiconductor device 10 of the first embodiment, the groove 90 surrounds the bonding material 7 when viewed in the first direction 101. This makes it possible to more effectively relieve stress on the bonding material 7 caused by the difference in the amount of thermal expansion.

[0049] According to the semiconductor device 10 of the first embodiment, the first semiconductor module 1 has an insulating layer 15. The insulating layer 15 is made of ceramic. Normally, when the insulating layer 15 is made of ceramic, the difference between the amount of thermal expansion of the first semiconductor module 1 and the amount of thermal expansion of the cooler 3 increases. This reduces the reliability of the semiconductor device 10. According to the semiconductor device 10 of the first embodiment, even when the insulating layer 15 is made of ceramic, the stress on the bonding material 7 can be sufficiently alleviated as described above. This makes it possible to suppress a reduction in the reliability of the semiconductor device 10.

[0050] According to the semiconductor device 10 of the first embodiment, the linear expansion coefficient of the sealing material 20 of the first semiconductor module 1 is smaller than the linear expansion coefficient of the cooler 3. Normally, when the linear expansion coefficient of the sealing material 20 is smaller than the linear expansion coefficient of the cooler 3, the difference between the amount of thermal expansion of the first semiconductor module 1 and the amount of thermal expansion of the cooler 3 increases. Therefore, the reliability of the semiconductor device 10 decreases. According to the semiconductor device 10 of the first embodiment, even when the linear expansion coefficient of the sealing material 20 is smaller than the linear expansion coefficient of the cooler 3, the stress on the bonding material 7 can be sufficiently alleviated as described above. Therefore, a decrease in the reliability of the semiconductor device 10 can be suppressed.

[0051] According to the semiconductor device 10 of the first embodiment, as viewed in the first direction 101, a groove 90 is provided inside a rectangle 98 connecting four first portions 51 of the fastening region 50. As viewed in the first direction 101, the outer edge of the rectangle 98 is located above the portion where the support surface 41 of the jacket portion 4 and the cooler 3 overlap, and is a position where the fastening force applied to the cooler 3 from each of the multiple fastening portions 5 is likely to concentrate. Therefore, when the groove 90 overlaps the outer edge of the rectangle 98 as viewed in the first direction 101, deformation of a portion of the cooler 3 close to the groove 90 may cause leakage of the coolant. According to the semiconductor device 10 of the first embodiment, the groove 90 is provided inside the rectangle 98, thereby suppressing deformation of the portion of the cooler 3 close to the groove 90. This effectively suppresses leakage of the coolant.

[0052] Modification of First Embodiment Next, the configuration of a semiconductor device 10 according to a modification of the first embodiment will be described with reference to FIG. 8 . As shown in FIG. 8 , the groove depth F may be greater than the groove width E. This allows the rigidity of the portion of the cooler 3 closer to the groove 90 to be weakened compared to when the groove depth F is smaller than the groove width E, assuming the groove width E is the same. Therefore, compared to when the groove depth F is smaller than the groove width E, the groove width E can be made smaller while maintaining the stress-relieving effect of the bonding material 7. This allows the semiconductor device 10 to be made smaller.

[0053] Second Embodiment Next, the configuration of a semiconductor device 10 according to a second embodiment will be described with reference to Figures 9 and 10. The semiconductor device 10 according to the second embodiment differs from the semiconductor device 10 according to the first embodiment mainly in that it has a plurality of semiconductor modules and that the grooves 90 have second groove portions 92, but is substantially the same as the semiconductor device 10 according to the first embodiment in other respects. The following description will focus on the differences from the semiconductor device 10 according to the first embodiment. The cross section shown in Figure 9 is a combined cross section taken along line IX-IX in Figure 10.

[0054] 9 , the semiconductor device 10 according to the second embodiment includes a plurality of semiconductor modules. Specifically, the semiconductor device 10 includes a second semiconductor module 2. The configuration of the second semiconductor module 2 may be substantially the same as the configuration of the first semiconductor module 1. Hereinafter, the first semiconductor module 1 and the second semiconductor module 2 will also be simply referred to as semiconductor modules.

[0055] The bonding material 7 has a first bonding material portion 71 and a second bonding material portion 72. The first bonding material portion 71 is provided between the first semiconductor module 1 and the cooler 3. From another perspective, the first semiconductor module 1 is provided on the first bonding material portion 71. The first bonding material portion 71 bonds the first semiconductor module 1 and the cooler 3 together.

[0056] The second bonding material portion 72 is provided between the second semiconductor module 2 and the cooler 3. From another perspective, the second semiconductor module 2 is provided on the second bonding material portion 72. The second bonding material portion 72 bonds the second semiconductor module 2 and the cooler 3 together.

[0057] The plate portion 8 has a second flat plate member 89. The second flat plate member 89 is in contact with the second bonding material portion 72. The first flat plate member 80 is in contact with the first bonding material portion 71. The second flat plate member 89 is spaced apart from the first flat plate member 80.

[0058] 9 and 10 , the groove 90 has a second groove portion 92. The second groove portion 92 is different from each of the first groove portion 91 and the third groove portion 93. As shown in Fig. 10 , when viewed in a first direction 101, the second groove portion 92 is provided between the first bonding material portion 71 and the second bonding material portion 72. The second groove portion 92 is continuous with the first groove portion 91. When viewed in the first direction 101, the second groove portion 92 is, for example, linear.

[0059] When viewed in the first direction 101, the first bonding material portion 71 is surrounded by the first groove portion 91 and the second groove portion 92. When viewed in the first direction 101, the second bonding material portion 72 is surrounded by the first groove portion 91, the second groove portion 92, and the third groove portion 93.

[0060] As shown in FIG. 9 , the plate portion 8 has a second plate member 82. The second plate member 82 is located between the first flat plate member 80 and the second flat plate member 89. From another perspective, the first flat plate member 80 is located between the first plate member 81 and the second plate member 82. The second flat plate member 89 is located between the second plate member 82 and the third plate member 83. The second plate member 82 is continuous with both the first flat plate member 80 and the second flat plate member 89. The second plate member 82 forms the bottom surface of the second groove portion 92. From another perspective, the second plate member 82 is located between the bottom surface of the second groove portion 92 and the second main surface 32.

[0061] When multiple semiconductor modules are bonded to the cooler 3, the amount of heat generated by the entire semiconductor device 10 increases compared to when there is only one semiconductor module. Therefore, compared to when there is only one semiconductor module, stress on the bonding material 7 due to the difference in the amount of thermal expansion between the semiconductor module and the cooler 3 increases. Furthermore, due to thermal interference between the heat generated by each of the multiple semiconductor modules, the temperature of the portions of the cooler 3 located between the multiple semiconductor modules in the first direction 101 is more likely to rise than other portions of the cooler 3. Therefore, when the semiconductor device 10 is operating, the portions of the cooler 3 located between the multiple semiconductor modules in the first direction 101 are more likely to deform.

[0062] According to the semiconductor device 10 of the second embodiment, the groove 90 has a second groove portion 92. When viewed in the first direction 101, the second groove portion 92 is provided between the first bonding material portion 71 and the second bonding material portion 72. Therefore, when the semiconductor device 10 is operated, the portion of the cooler 3 close to the second groove portion 92 deforms preferentially. This effectively suppresses deformation of the portion of the cooler 3 that is in contact with the bonding material 7. Therefore, it is possible to effectively relieve stress on the bonding material 7 while suppressing an increase in the size of the semiconductor device 10. As a result, it is possible to effectively improve the reliability of the semiconductor device 10.

[0063] Third Embodiment Next, the configuration of a semiconductor device 10 according to a third embodiment will be described with reference to Figure 11. The semiconductor device 10 according to the third embodiment differs from the semiconductor device 10 according to the second embodiment mainly in that leakage of coolant is effectively suppressed, but is otherwise substantially the same as the semiconductor device 10 according to the first embodiment. The following description will focus on the differences from the semiconductor device 10 according to the second embodiment.

[0064] As shown in FIG. 11 , the thickness T of the plate portion 8 of the cooler 3 is the thickness T of the plate portion 8 in the thickness direction from the first main surface 31 to the second main surface 32. Specifically, the thickness T is the thickness T of the portion of the plate portion 8 that is thickest in the thickness direction. The groove depth F is smaller than half the thickness T of the plate portion 8. From another perspective, the thickness of each of the first plate member 81, the second plate member 82, and the third plate member 83 in the thickness direction is greater than half the thickness T of the plate portion 8. The thickness T of the plate portion 8 is, for example, 2 mm or more. The thickness T may be, for example, 3 mm or more, or 5 mm or more.

[0065] In order to stabilize the operation of the semiconductor device 10, it is necessary to suppress leakage of the coolant flowing between the jacket portion 4 and the cooler 3. In order to suppress leakage of the coolant, it is necessary to suppress the occurrence of a gap between the cooler 3 and the jacket portion 4 due to deformation of the cooler 3.

[0066] In the semiconductor device 10 according to the third embodiment, the groove depth F is smaller than half the thickness T of the plate portion 8. This makes it possible to prevent the portion of the cooler 3 close to the groove 90 from being excessively deformed. This makes it possible to prevent a gap from being generated between the cooler 3 and the jacket portion 4 due to deformation of the cooler 3. This makes it possible to prevent leakage of the coolant. As a result, the operational stability of the semiconductor device 10 can be improved.

[0067] According to the semiconductor device 10 of the third embodiment, the thickness T of the plate portion 8 is 2 mm or more. This effectively prevents deformation of the cooler 3. This effectively prevents leakage of the coolant. As a result, the operational stability of the semiconductor device 10 can be effectively improved.

[0068] Modification of Third Embodiment Next, the configuration of a semiconductor device 10 according to a modification of the third embodiment will be described with reference to FIG. 12 . As shown in FIG. 12 , the semiconductor device 10 may have a third bonding material portion 73. From another perspective, the semiconductor device 10 may have three semiconductor modules (not shown). The third bonding material portion 73 is part of the bonding material 7 (see FIG. 10 ). The first bonding material portion 71, the second bonding material portion 72, and the third bonding material portion 73 are arranged, for example, in a row.

[0069] The groove 90 may have a sixth groove portion 96. When viewed in the first direction 101, the sixth groove portion 96 is provided between the second bonding material portion 72 and the third bonding material portion 73. The sixth groove portion 96 is continuous with the first groove portion 91. When viewed in the first direction 101, the sixth groove portion 96 is provided between the second groove portion 92 and the third groove portion 93. When viewed in the first direction 101, the sixth groove portion 96 is, for example, linear. When viewed in the first direction 101, the extension direction of the sixth groove portion 96 may be parallel to the extension direction of the third groove portion 93.

[0070] The fastening region 50 of the cooler 3 may have one or more second portions 52. Specifically, the fastening region 50 has, for example, two second portions 52. Each of the two second portions 52 is a region different from each of the four first portions 51. From another perspective, the cooler 3 and the jacket portion 4 are fastened together by six fastening portions 5 (see FIG. 11 ).

[0071] As viewed in the first direction 101, each of the two second portions 52 is provided on the outer edge of the rectangle 98, for example. From another perspective, as viewed in the first direction 101, the rectangle 98 can be formed, for example, by connecting the first portion 51 and the second portion 52. Note that as viewed in the first direction 101, each of the two second portions 52 may be provided inside the rectangle 98.

[0072] When the number of semiconductor modules included in the semiconductor device 10 increases, thereby increasing the length of the cooler 3, the number of fastening portions 5 may be set to five or more in order to suppress leakage of the coolant. According to the first modification of the third embodiment, even when the number of fastening portions 5 is five or more, deformation of the portion of the cooler 3 near the groove 90 can be suppressed. This makes it possible to effectively suppress leakage of the coolant.

[0073] 13 , a semiconductor device 10 according to a fourth embodiment differs from the semiconductor device 10 according to the second embodiment mainly in that each of the plurality of heat dissipation portions 9 is provided in the first direction 101 relative to the groove 90, but is otherwise substantially the same as the semiconductor device 10 according to the second embodiment. The following description will focus on the differences from the semiconductor device 10 according to the second embodiment.

[0074] 13 , in the semiconductor device 10 according to the fourth embodiment, at least one of the plurality of heat dissipation portions 9 is provided in the first direction 101 with respect to the groove 90. Specifically, at least one of the plurality of heat dissipation portions 9 is provided in the first direction 101 with respect to the first groove portion 91. From another perspective, at least one of the plurality of heat dissipation portions 9 is continuous with the first plate member 81.

[0075] At least one of the plurality of heat dissipation portions 9 is provided in the first direction 101 with respect to the second groove portion 92. From another perspective, at least one of the plurality of heat dissipation portions 9 is continuous with the second plate member 82. At least one of the plurality of heat dissipation portions 9 is provided in the first direction 101 with respect to the third groove portion 93. From another perspective, at least one of the plurality of heat dissipation portions 9 is continuous with the third plate member 83.

[0076] In the portion of the cooler 3 close to the groove 90, heat is less likely to be transferred in the direction along the first main surface 31 than in other portions of the cooler 3. According to the semiconductor device 10 according to the fourth embodiment, at least one of the plurality of heat dissipation portions 9 is continuous with the first plate member 81. Therefore, it is possible to improve the heat dissipation performance in the portion of the cooler 3 close to the first groove portion 91.

[0077] According to the semiconductor device 10 of the fourth embodiment, at least one of the plurality of heat dissipation portions 9 is continuous with the second plate member 82. This improves the heat dissipation performance of the portion of the cooler 3 close to the second groove 92. The portion of the cooler 3 close to the second groove 92 is prone to temperature rise due to thermal interference between the heat generated by the two adjacent semiconductor modules. Therefore, by improving the heat dissipation performance of the portion of the cooler 3 close to the second groove 92, the reliability of the semiconductor device 10 can be effectively improved.

[0078] Fifth Embodiment Next, the configuration of a semiconductor device 10 according to a fifth embodiment will be described with reference to Figures 14 and 15. The semiconductor device 10 according to the fifth embodiment differs from the semiconductor device 10 according to the second embodiment mainly in that the cooler 3 has a non-bonded region, but is otherwise substantially the same as the semiconductor device 10 according to the second embodiment. The following description will focus on the differences from the semiconductor device 10 according to the second embodiment.

[0079] 14 and 15 , the cooler 3 has a first non-bonding region 56. The first non-bonding region 56 is provided on the first main surface 31. The first non-bonding region 56 can suppress the wetting and spreading of the material that constitutes the bonding material 7. Specifically, when the material that constitutes the bonding material 7 (e.g., solder) melts, the first non-bonding region 56 can suppress the wetting and spreading of the molten material over the first non-bonding region 56.

[0080] In the semiconductor device 10 according to the fifth embodiment, when the cooler 3 is made of aluminum, the first non-bonding region 56 is, for example, a pure aluminum region or a region coated with resist. The pure aluminum region is a region on the aluminum surface that has not been subjected to surface treatments such as resist coating, laser roughening, or plating. From another perspective, the first non-bonding region 56 is, for example, a region covered with an aluminum oxide film.

[0081] When the cooler 3 is made of copper, the first non-bonding region 56 is, for example, a region coated with a resist or a region roughened using a laser.

[0082] 15 , as viewed in the first direction 101, the first non-bonding region 56 is provided between the groove 90 and the bonding material 7. Specifically, as viewed in the first direction 101, the first non-bonding region 56 is provided between each of the first groove portion 91 and the second groove portion 92 and the first bonding material portion 71. As viewed in the first direction 101, the first non-bonding region 56 is provided between each of the first groove portion 91, the second groove portion 92, and the third groove portion 93 and the second bonding material portion 72. As viewed in the first direction 101, the first non-bonding region 56 surrounds each of the first bonding material portion 71 and the second bonding material portion 72. As viewed in the first direction 101, the first non-bonding region 56 is surrounded by the groove 90.

[0083] For example, if the bonding material 7 is made of solder, the material that makes up the bonding material 7 melts when the semiconductor module and the cooler 3 are joined together. In this case, the melted material wets and spreads, and the bonding material 7 may not assume the desired shape.

[0084] According to the semiconductor device 10 of the fifth embodiment, the cooler 3 has a first non-bonding region 56. When viewed in the first direction 101, the first non-bonding region 56 is provided between the groove 90 and the bonding material 7. Therefore, when the material constituting the bonding material 7 melts during bonding between the semiconductor module and the cooler 3, unintended wetting and spreading of the material is suppressed. This suppresses the occurrence of shape abnormalities in the bonding material 7. As a result, the reliability of the semiconductor device 10 can be improved.

[0085] First Modification of Fifth Embodiment Next, the configuration of a semiconductor device 10 according to a first modification of the fifth embodiment will be described with reference to FIG. 16 . As shown in FIG. 16 , the cooler 3 may have a plating layer 59. The plating layer 59 covers at least a portion of the plate portion 8 and the plurality of heat dissipation portions 9. The plating layer 59 may cover the entire plate portion 8 and the plurality of heat dissipation portions 9. The plating layer 59 is made of, for example, nickel. The surface of the cooler 3 is made of, for example, the plating layer 59 and a first non-bonding region 56.

[0086] In the semiconductor device 10 according to the first modification of the fifth embodiment, the first non-bonding region 56 may be, for example, a region where a resist is applied on the plating layer 59. The first non-bonding region 56 may be, for example, a pure aluminum region that is not covered with the plating layer 59. The first non-bonding region 56 may be a region that is not covered with the plating layer 59 and that has been subjected to a roughening process using a laser.

[0087] For example, if the plate portion 8 and the plurality of heat dissipation portions 9 are made of copper, impurities in the coolant may corrode the plate portion 8 and the plurality of heat dissipation portions 9. In the semiconductor device 10 according to the first modification of the fifth embodiment, the cooler 3 has the plating layer 59, which can suppress corrosion of the plate portion 8 and the plurality of heat dissipation portions 9. This can improve the reliability of the semiconductor device 10.

[0088] Second Modification of Fifth Embodiment Next, the configuration of a semiconductor device 10 according to a second modification of the fifth embodiment will be described with reference to FIGS. 17 and 18 . As shown in FIGS. 17 and 18 , the cooler 3 may have a second non-bonding region 57. The second non-bonding region 57 can suppress the wetting and spreading of the material that constitutes the bonding material 7. The second non-bonding region 57 is continuous with the first non-bonding region 56. The position of the second non-bonding region 57 is different from the position of the first non-bonding region, but in other respects, the configuration of the second non-bonding region 57 is substantially the same as that of the first non-bonding region 56.

[0089] 17 , the second non-bonding region 57 covers the bottom surface and the side surface of the groove 90. From another perspective, the second non-bonding region 57 is provided inside the groove 90. As shown in FIG. 18 , when viewed in the first direction 101, the second non-bonding region 57 surrounds each of the first bonding material portion 71 and the second bonding material portion 72.

[0090] When the material constituting the bonding material 7 melts during bonding between the semiconductor module and the cooler 3, the material may flow into the groove 90. In this case, the solidified material inhibits deformation of the portion of the cooler 3 close to the groove 90. Therefore, the reliability of the semiconductor device 10 may not be sufficiently improved.

[0091] According to the second modification of the fifth embodiment, the second non-bonding region 57 covers the bottom surface and the side surface of the groove 90, which makes it possible to prevent the material constituting the molten bonding material 7 from entering the groove 90. This makes it possible to stably improve the reliability of the semiconductor device 10.

[0092] As with the semiconductor device 10 according to the first modification of the fifth embodiment, in the semiconductor device 10 according to the second modification of the fifth embodiment, the cooler 3 may have a plating layer 59. The surface of the cooler 3 may be configured by, for example, the plating layer 59, a first non-bonding region 56, and a second non-bonding region 57.

[0093] Sixth Embodiment Next, the configuration of a semiconductor device 10 according to a sixth embodiment will be described with reference to Figure 19. The semiconductor device 10 according to the sixth embodiment differs from the semiconductor device 10 according to the first embodiment mainly in that the sealing material 20 has a protrusion 28, but is otherwise substantially the same as the semiconductor device 10 according to the first embodiment. The following description will focus on the differences from the semiconductor device 10 according to the first embodiment.

[0094] 19 , in the semiconductor device 10 according to the sixth embodiment, the sealing material 20 may have a main body portion 27 and a protrusion portion 28. The main body portion 27 is located on the contact surface between the first conductor pattern 11 and the bonding material 7, in a direction from the bonding material 7 toward the first conductor pattern 11. The direction from the bonding material 7 toward the first conductor pattern 11 is opposite to the first direction 101. The main body portion 27 covers the insulating layer 15, the second conductor pattern 12, the first semiconductor element 13, and the second semiconductor element 14. The main body portion 27 covers a portion of the first conductor pattern 11.

[0095] The protrusion 28 is continuous with the main body 27. The protrusion 28 extends in a direction from the main body 27 toward the cooler 3. The direction from the main body 27 toward the cooler 3 is, for example, the same direction as the first direction 101. On the first main surface 31, the protrusion 28 is in contact with the cooler 3. The protrusion 28 surrounds the bonding material 7.

[0096] By providing the protrusions 28 to the sealing material 20, the material constituting the molten bonding material 7 can be prevented from flowing toward the grooves 90 when bonding the semiconductor module and the cooler 3 together. This makes it possible to stably improve the reliability of the semiconductor device 10. In particular, when the warpage of the semiconductor module varies greatly, a large amount of solder may be supplied to prevent a solder shortage. In this case, the molten solder is likely to enter the grooves 90. Even in this case, the semiconductor device 10 according to the sixth embodiment makes it possible to stably improve the reliability of the semiconductor device 10.

[0097] Seventh Embodiment Next, the configuration of a semiconductor device 10 according to a seventh embodiment will be described with reference to Figures 20 and 21. The semiconductor device 10 according to the seventh embodiment differs from the semiconductor device 10 according to the second embodiment mainly in that the groove 90 has a fourth groove portion 94 and a fifth groove portion 95, but is otherwise substantially the same as the semiconductor device 10 according to the second embodiment. The following description will focus on the differences from the semiconductor device 10 according to the second embodiment.

[0098] 20 and 21 , in the semiconductor device 10 according to the seventh embodiment, the groove 90 has a fourth groove portion 94 and a fifth groove portion 95. The fourth groove portion 94 is provided in the intermediate portion 86. The fourth groove portion 94 is different from each of the first groove portion 91, the second groove portion 92, and the third groove portion 93. The fifth groove portion 95 is provided in the intermediate portion 86. The fifth groove portion 95 is different from each of the first groove portion 91, the second groove portion 92, the third groove portion 93, and the fourth groove portion 94.

[0099] 21 , as viewed in the first direction 101, the fourth groove portion 94 is provided between the fastening portion 5 and the first groove portion 91. As viewed in the first direction 101, the fourth groove portion 94 is provided on the opposite side of the bonding material 7 from the first groove portion 91. The fourth groove portion 94 is, for example, spaced apart from the first groove portion 91 and the third groove portion 93. As viewed in the first direction 101, the fourth groove portion 94 is linear. As viewed in the first direction 101, the extension direction of the fourth groove portion 94 may be parallel to the extension direction of the third groove portion 93.

[0100] As viewed in the first direction 101, the fifth groove portion 95 is provided between the fastening portion 5 and the third groove portion 93. As viewed in the first direction 101, the fifth groove portion 95 is provided on the opposite side of the bonding material 7 from the third groove portion 93. The fifth groove portion 95 is, for example, spaced apart from the first groove portion 91 and the third groove portion 93. As viewed in the first direction 101, the fifth groove portion 95 is linear. As viewed in the first direction 101, the extension direction of the fifth groove portion 95 may be parallel to the extension direction of the third groove portion 93.

[0101] In the semiconductor device 10 according to the seventh embodiment, the fourth groove 94 is provided, thereby reducing the amount of deformation of the portion of the cooler 3 close to the first groove 91. This makes it possible to suppress fatigue of the portion of the cooler 3 close to the first groove 91. Similarly, the fifth groove 95 is provided, thereby making it possible to suppress fatigue of the portion of the cooler 3 close to the third groove 93.

[0102] Note that one or more grooves may be provided between the fourth groove 94 and the first groove 91. Similarly, one or more grooves may be provided between the fifth groove 95 and the third groove 93.

[0103] Eighth Embodiment Next, the configuration of a semiconductor device 10 according to an eighth embodiment will be described with reference to Figures 22 and 23. The semiconductor device 10 according to the eighth embodiment differs from the semiconductor device 10 according to the second embodiment mainly in the shape of each of the plurality of heat dissipation portions 9, but is otherwise substantially the same as the semiconductor device 10 according to the second embodiment. The following description will focus on the differences from the semiconductor device 10 according to the second embodiment. For ease of explanation, the jacket portion 4 and the fastening portion 5 are not shown in Figure 22. Figure 23 shows the configuration of the cooler 3 as viewed in a direction perpendicular to the second main surface 32.

[0104] 22 and 23 , in the semiconductor device 10 according to the eighth embodiment, each of the plurality of heat dissipation portions 9 has a polygonal pillar shape. As shown in Fig. 22 , the plate portion 8 has a main body member 33 and a connecting plate member 34. The main body member 33 forms a part of the second main surface 32 and the first main surface 31. The main body member 33 is provided with grooves 90 and fastening holes 99.

[0105] The connecting plate member 34 connects the main body member 33 and the plurality of heat dissipation units 9. The connecting plate member 34 is provided between the main body member 33 and the plurality of heat dissipation units 9 in the first direction 101. The connecting plate member 34 constitutes a part of the second main surface 32. The connecting plate member 34 is surrounded by, for example, the jacket portion 4. The connecting plate member 34 is located within the accommodation portion 49 of the jacket portion 4.

[0106] 23 , when viewed along the direction in which the heat dissipation units 9 extend, the outer shape of each of the heat dissipation units 9 is polygonal. Specifically, when viewed along the direction in which the heat dissipation units 9 extend, the outer shape of each of the heat dissipation units 9 is, for example, hexagonal. From another perspective, the shape of each of the heat dissipation units 9 is a hexagonal prism. Note that a polygonal outer shape includes cases in which the corners of the outer shape are rounded. When viewed along the direction in which the heat dissipation units 9 extend, one side of each of two adjacent heat dissipation units 9 may be parallel to each other.

[0107] The second main surface 32 has an outer circumferential region 35 and a heat dissipation region 36. The outer circumferential region 35 is a region that is in contact with the jacket portion 4. Specifically, the outer circumferential region 35 is in contact with a support surface 41 (see FIG. 22 ) of the jacket portion 4 and the elastic body 6 (see FIG. 22 ). The outer circumferential region 35 is formed by, for example, the main body member 33.

[0108] The heat dissipation region 36 is surrounded by the outer peripheral region 35. A plurality of heat dissipation portions 9 are provided in the heat dissipation region 36. The heat dissipation region 36 is formed, for example, by a connecting plate member 34. When viewed along the direction in which each of the plurality of heat dissipation portions 9 extends, the shape of the heat dissipation region 36 is, for example, rectangular.

[0109] The total area of ​​the heat dissipation sections 9 as viewed along the extension direction of the heat dissipation sections 9 is defined as a first area. The first area is the sum of the areas of the heat dissipation sections 9. The area of ​​the heat dissipation region 36 as viewed along the extension direction of the heat dissipation sections 9 is defined as a second area. If the shape of the heat dissipation region 36 as viewed along the extension direction of the heat dissipation sections 9 is rectangular, the second area is the value obtained by multiplying the height H of the heat dissipation region 36 by the width W of the heat dissipation region 36. The second area is the value obtained by adding the area of ​​the heat dissipation region 36 where the heat dissipation sections 9 do not overlap to the first area.

[0110] The value obtained by dividing the first area by the second area is 0.2 or more. The value obtained by dividing the first area by the second area may be, for example, 0.35 or more, or 0.5 or more. The value obtained by dividing the first area by the second area may be, for example, 0.9 or less, or 0.8 or less.

[0111] According to the semiconductor device 10 of the eighth embodiment, the outer shape of each of the heat dissipation portions 9 is polygonal when viewed along the direction in which the heat dissipation portions 9 extend. Therefore, compared to when the outer shape of each of the heat dissipation portions 9 is circular, the corners of the heat dissipation portions 9 allow the flow of the coolant to be more complex. Therefore, the leading edge effect can suppress the formation of a thermal boundary layer near the surface of each of the heat dissipation portions 9. This can improve the efficiency of heat exchange between the coolant and each of the heat dissipation portions 9. As a result, the miniaturization and high density of the semiconductor device 10 can be promoted.

[0112] According to the semiconductor device 10 of the eighth embodiment, the outer shape of each of the heat dissipation portions 9 is hexagonal when viewed along the extending direction of the heat dissipation portions 9. This effectively improves the efficiency of heat exchange between the coolant and each of the heat dissipation portions 9.

[0113] When viewed along the direction in which the heat dissipation portions 9 extend, if the total area (first area) of the heat dissipation portions 9 is excessively small, the amount of heat transferred from each of the heat dissipation portions 9 to the coolant will be excessively small. In the semiconductor device 10 according to the eighth embodiment, the value obtained by dividing the first area by the second area is 0.2 or greater. This allows the amount of heat transferred from each of the heat dissipation portions 9 to the coolant to be sufficiently large. As a result, the miniaturization and high density of the semiconductor device 10 can be effectively promoted.

[0114] Ninth Embodiment In this embodiment, a reverse conducting insulated gate bipolar transistor (RC-IGBT) is used as the semiconductor element in the semiconductor device 10 according to any of the first to eighth embodiments described above. In other words, the semiconductor element may be an RC-IGBT. By using an RC-IGBT as the semiconductor element, the number of semiconductor elements can be reduced. This allows the semiconductor module to be miniaturized. As a result, the semiconductor device 10 can be miniaturized.

[0115] Tenth Embodiment In this embodiment, silicon carbide (SiC) is used as the semiconductor element in the semiconductor device 10 according to the first to eighth embodiments described above. In other words, the semiconductor element may be made of silicon carbide. By making the semiconductor element out of SiC, which has a relatively low loss, it is possible to facilitate miniaturization of the semiconductor device 10 and increase in the density of the semiconductor device 10.

[0116] Eleventh Embodiment In this embodiment, the semiconductor device according to the first to tenth embodiments is applied to a power conversion device. Although the present disclosure is not limited to a specific power conversion device, the eleventh embodiment will be described below as an example in which the present invention is applied to a three-phase inverter.

[0117] FIG. 24 is a block diagram showing the configuration of a power conversion system to which the power conversion device according to this embodiment is applied.

[0118] The power conversion system shown in Fig. 24 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 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 100 may also be composed of a DC / DC converter that converts DC power output from a DC system into a predetermined power.

[0119] 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. 24 , the power conversion device 200 includes a main conversion circuit 201 that converts DC power into AC power and outputs it, a drive circuit 202 that outputs drive signals that drive each switching element of the main conversion circuit 201, and a control circuit 203 that outputs control signals to the drive circuit 202.

[0120] 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.

[0121] 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. The main conversion circuit 201 according to this embodiment is a two-level, three-phase full-bridge circuit, and can be configured with six switching elements and six freewheel diodes connected in anti-parallel to each switching element. Each switching element of the main conversion circuit 201 is a semiconductor device according to any one of the first to tenth embodiments. Two switching elements are connected in series to form upper and lower arms, and each upper and lower arm constitutes one 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.

[0122] The drive circuit 202 generates drive signals for driving 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 202 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 higher 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 lower than the threshold voltage of the switching element.

[0123] 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 the drive circuit 202 so that an on signal is output to the switching element that should be in the on state at each point in time, and an off signal is output to the switching element that should be in the off state at each point in time. In accordance with this control signal, the drive circuit 202 outputs an on signal or an off signal as a drive signal to the control electrode of each switching element.

[0124] In the power conversion device according to this embodiment, the semiconductor devices according to the first to tenth embodiments are applied as the switching elements of the main conversion circuit 201, and therefore, improved reliability can be achieved.

[0125] In this embodiment, an example in which the present invention is applied to a two-level three-phase inverter has been described, but the present invention is not limited to this and can be applied to various power conversion devices. In this embodiment, a two-level power conversion device is described, but a three-level or multi-level power conversion device may also be used. In addition, when power is supplied to a single-phase load, the present invention may also be applied to a single-phase inverter. Furthermore, when power is supplied to a DC load, etc., the present invention can also be applied to a DC / DC converter or an AC / DC converter.

[0126] Furthermore, the power conversion device to which the present invention is applied is not limited to cases in which the above-mentioned 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.

[0127] The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present disclosure is defined by the claims, not the above description, and is intended to include meanings equivalent to the claims and all modifications within the scope thereof.

[0128] REFERENCE SIGNS LIST 1 First semiconductor module, 2 Second semiconductor module, 3 Cooler, 4 Jacket portion, 5 Fastening portion, 6 Elastic body, 7 Bonding material, 8 Plate portion, 9 Heat dissipation portion, 10 Semiconductor device, 11 First conductor pattern, 12 Second conductor pattern, 13 First semiconductor element, 14 Second semiconductor element, 15 Insulating layer, 16 First surface, 17 Second surface, 18 First terminal, 19 Second terminal, 20 Sealing material, 21 First internal bonding material, 22 Second internal bonding material, 23 Third internal bonding material, 24 Fourth internal bonding material, 25 Wiring, 27 Main body portion, 28 Protrusion portion, 30 Insulating substrate, 31 First main surface, 32 Second main surface, 33 Main body member, 34 Connecting plate member, 35 Outer periphery region, 36 Heat dissipation region, 41 Support surface, 42 Female screw, 43 Holding groove, 49 Storage portion, 50 Fastened region, 51 First portion, 52 Second portion, 56 First non-bonding region, 57 Second non-bonding region, 59 Plating layer, 71 First bonding material portion, 72 Second bonding material portion, 73 Third bonding material portion, 80 First flat plate member, 81 First plate member, 82 Second plate member, 83 Third plate member, 86 Middle portion, 87 Outer periphery, 89 Second flat plate member, 90 Groove, 91 First groove portion, 92 Second groove portion, 93 Third groove portion, 94 Fourth groove portion, 95 Fifth groove portion, 96 Sixth groove portion, 97 Line segment, 98 Rectangle, 99 Fastening hole, 100 Power source, 101 First direction, 102 Second direction, 103 Third direction, 200 Power conversion device, 201 Main conversion circuit, 202 Drive circuit, 203 Control circuit, 300 Load, A Arrow, B Crack tolerance, C Crack, D1 first distance, D2 second distance, D3 third distance, D4 ​​fourth distance, E groove width, F groove depth, H height, L1 first length, L2 second length, T thickness, W width.

Claims

1. A semiconductor device comprising: a cooler having a first main surface; a bonding material provided on the first main surface; a first semiconductor module provided on the bonding material; and a fastening portion fastening the cooler to a jacket portion; a groove is provided in the first main surface; when viewed in a first direction from the bonding material toward the first main surface, a portion of the groove is provided between the fastening portion and the bonding material; the cooler has a fastened region formed by an area of ​​the cooler that is in contact with the fastening portion; a second direction is a direction that is shortest from the fastened region to the bonding material; when viewed in the first direction, a first distance is a distance between the groove and the bonding material in the second direction; and when viewed in the first direction, a second distance is a distance between the fastened region and the groove in the second direction, the first distance is shorter than the second distance.

2. The semiconductor device described in claim 1, further comprising a second semiconductor module different from the first semiconductor module, wherein the bonding material has a first bonding material portion provided between the cooler and the first semiconductor module and a second bonding material portion provided between the cooler and the second semiconductor module, wherein the groove has a second groove portion different from the portion, and wherein, when viewed in the first direction, the second groove portion is provided between the first bonding material portion and the second bonding material portion.

3. A semiconductor device as described in claim 1 or claim 2, further comprising: the jacket portion; and an elastic body sandwiched between the cooler and the jacket portion, wherein, when viewed in the first direction, the elastic body is located between the fastening portion and the bonding material, and when the shortest distance in the second direction from the contact surface between the elastic body and the cooler to the groove is defined as a third distance, the first distance is shorter than the third distance.

4. A semiconductor device according to any one of claims 1 to 3, wherein the first semiconductor module comprises: an insulating layer having a first surface and a second surface opposite the first surface; a first conductor pattern provided on the first surface and joined to the cooler by the bonding material; a second conductor pattern provided on the second surface; a semiconductor element electrically connected to the second conductor pattern; and a sealing material covering the insulating layer, the second conductor pattern, and the semiconductor element.

5. The semiconductor device described in claim 4, wherein the groove has a first groove portion that is the part, and a third groove portion that is on the opposite side of the bonding material from the first groove portion when viewed in the first direction, and the distance between the first groove portion and the third groove portion in the direction from the first groove portion to the third groove portion is longer than the length of the first conductor pattern.

6. The semiconductor device according to claim 4 or 5, wherein the insulating layer is made of ceramic.

7. The semiconductor device according to any one of claims 4 to 6, wherein the linear expansion coefficient of the sealing material is smaller than the linear expansion coefficient of the cooler.

8. The semiconductor device according to any one of claims 1 to 7, wherein the groove surrounds the bonding material when viewed in the first direction.

9. A semiconductor device as described in any one of claims 1 to 8, wherein the cooler has a plate portion constituting the first main surface, the plate portion having a second main surface opposite the first main surface, and the depth of the groove in the thickness direction from the first main surface toward the second main surface is greater than the width of the groove in a direction perpendicular to the direction in which the groove extends as viewed in the first direction.

10. A semiconductor device as described in any one of claims 1 to 8, wherein the cooler has a plate portion constituting the first main surface, the plate portion has a second main surface opposite the first main surface, and the depth of the groove in the thickness direction from the first main surface toward the second main surface is less than half the thickness of the plate portion.

11. The semiconductor device according to claim 10, wherein the thickness of the plate portion in the thickness direction is 2 mm or more.

12. A semiconductor device according to any one of claims 1 to 11, wherein the fastening region has four first portions spaced apart from one another, and when viewed in the first direction, the groove is provided inside a rectangle formed by connecting the four first portions.

13. The semiconductor device described in claim 12, wherein the fastening region has one or more second portions different from the four first portions, and when viewed in the first direction, the one or more second portions are provided on the outer edge of the rectangle or inside the rectangle.

14. A semiconductor device as described in any one of claims 1 to 8, wherein the cooler has a plate portion that constitutes the first main surface and has a second main surface opposite the first main surface, and a plurality of heat dissipation portions that are connected to the plate portion on the second main surface, the plate portion having a first plate member located between the bottom surface of the portion of the groove and the second main surface, and at least one of the plurality of heat dissipation portions is connected to the first plate member.

15. The semiconductor device described in claim 2, wherein the cooler comprises: a plate portion constituting the first main surface and having a second main surface opposite the first main surface; and a plurality of heat dissipation portions connected to the plate portion on the second main surface, the plate portion having a second plate member located between the bottom surface of the second groove portion and the second main surface, and at least one of the plurality of heat dissipation portions connected to the second plate member.

16. A semiconductor device as described in any one of claims 1 to 8, wherein the cooler has a first non-bonding region capable of suppressing the spreading of the material constituting the bonding material, and when viewed in the first direction, the first non-bonding region is provided between the groove and the bonding material.

17. The semiconductor device described in claim 16, wherein the cooler comprises: a plate portion constituting the first main surface and having a second main surface opposite the first main surface; a plurality of heat dissipation portions connected to the plate portion on the second main surface; and a plating layer covering at least a portion of the plate portion and the plurality of heat dissipation portions.

18. A semiconductor device as described in claim 16 or claim 17, wherein the cooler has a second non-bonding region that can suppress the spreading of the material that constitutes the bonding material, and the second non-bonding region covers each of the bottom surface of the groove and the side surface of the groove.

19. A semiconductor device as described in any one of claims 4 to 7, wherein the sealing material has a main body portion located in a direction from the bonding material toward the first conductor pattern relative to the contact surface between the first conductor pattern and the bonding material, and a protrusion portion connected to the main body portion and extending from the main body portion in a direction toward the cooler.

20. A semiconductor device as described in any one of claims 1 to 19, wherein the groove has a fourth groove portion different from the portion, and when viewed in the first direction, the fourth groove portion is provided between the fastening portion and the portion of the groove.

21. A semiconductor device as described in any one of claims 1 to 8, wherein the cooler has: a plate portion that constitutes the first main surface and has a second main surface opposite the first main surface; and a plurality of heat dissipation portions that are connected to the plate portion on the second main surface, and when viewed along the direction in which the plurality of heat dissipation portions extend, the outer shape of each of the plurality of heat dissipation portions is polygonal.

22. The semiconductor device according to claim 21, wherein the outer shape of each of the plurality of heat dissipation portions is hexagonal when viewed along the direction in which the plurality of heat dissipation portions extend.

23. A semiconductor device as described in claim 21 or claim 22, wherein the second main surface has an outer peripheral region in contact with the jacket portion, and a heat dissipation region surrounded by the outer peripheral region and in which the plurality of heat dissipation portions are provided, and when viewed along the direction in which the plurality of heat dissipation portions extend, the value obtained by dividing the total area of ​​the plurality of heat dissipation portions by the area of ​​the heat dissipation region is 0.2 or more.

24. The semiconductor device according to any one of claims 4 to 7, wherein the semiconductor element is a reverse conducting insulated gate bipolar transistor.

25. The semiconductor device according to any one of claims 4 to 7, wherein the semiconductor element is made of silicon carbide.

26. A power conversion device comprising: a main conversion circuit having a semiconductor device according to any one of claims 1 to 25, which converts input power and outputs it; a drive circuit which outputs a drive signal to the semiconductor device for driving the semiconductor device; and a control circuit which outputs a control signal to the drive circuit for controlling the drive circuit.

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