Semiconductor device and heat sink

Abstract

A semiconductor device (100, 200) according to the present disclosure comprises: a semiconductor module (10) comprising a heat dissipation plate (1); a heat sink (20) comprising a mounting surface (21) over which the semiconductor module (10) is mounted; a heat dissipation member (30) interposed between the heat dissipation plate (1) and the heat sink (20) and having flexibility; and a spacer (22). The semiconductor module (10) and the heat sink (20) are fixed to each other by a fixing member (7). The semiconductor module (10) and the heat sink (20) each comprise a fixing portion (6a, 6b) to which the fixing member (7) is attached. The spacer (22) is provided on the fixing portion (6a) of the semiconductor module (10) or the fixing portion (6b) of the heat sink (20).

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This non-provisional application is based on Japanese Patent Application No. 2024-037299, filed with the Japan Patent Office on March 11, 2024, the entire contents of which are hereby incorporated by reference. BACKGROUND OF THE INVENTIONField of the invention

[0002] The present disclosure relates to a semiconductor device and a heat sink. Description of the state of the art

[0003] A prior art technique is known in which heat generated by a semiconductor module is dissipated by inserting a heat dissipation sheet or a heat dissipation member having flexibility, such as grease, between a heat sink and the semiconductor module. Furthermore, another prior art technique is known in which a semiconductor module and a heat sink are fixed to each other by a fastening member, such as a screw.

[0004] Prior art configurations of a semiconductor module and a heat sink are described, for example, in Japanese Patent Laid-Open No. 2023-000129. Japanese Patent Laid-Open No. 2023-000129 discloses a power semiconductor module provided with a semiconductor module including a base plate and a heat sink having a mounting surface on which the semiconductor module is mounted. Thermally conductive grease, which is a heat dissipation element, is interposed between the base plate provided on the lower surface of the semiconductor module and the heat sink, and the semiconductor module and the heat sink are secured together by screws.

[0005] In the power semiconductor module described in Japanese Patent Application Laid-Open No. 2023-000129, when the semiconductor module and the heat sink are fastened together by a screw, an axial force is generated, and the axial force is concentrated at the fastening point. As a result of the axial force being concentrated at the fastening point, the fastening point in the semiconductor module sinks relative to the central portion of the semiconductor module located away from the fastening point. Consequently, a stress difference occurs between the heat dissipation member interposed between the base plate provided on the lower surface of the semiconductor module and the heat sink near the fastening point and the central portion located away from the fastening point.There has been a problem that a stress difference occurring in a heat dissipation member causes a crack in a member with relatively low flexibility, such as an insulating plate included in a semiconductor module.

[0006] The present disclosure has been developed to solve the above problem and aims to provide a semiconductor device that enables, when a semiconductor module and a heat sink are fixed to each other by a fixing member, to prevent the occurrence of a stress difference in a heat dissipation member and to prevent a crack caused in an insulating plate of the semiconductor module or the like due to stress. SUMMARY OF THE INVENTION

[0007] A semiconductor device according to the present disclosure includes: a semiconductor module including a heat dissipation plate; a heat sink including a mounting surface over which the semiconductor module is mounted; and a heat dissipation member interposed between the heat dissipation plate and the heat sink and having flexibility. The semiconductor module and the heat sink are fixed to each other by a fixing member, the semiconductor module and the heat sink each include a fixing portion to which the fixing member is attached, and a spacer is provided at the fixing portion between the semiconductor module and the heat sink.

[0008] The above and other objects, features, aspects and advantages of the present disclosure will become apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view of a semiconductor device according to a first embodiment. Fig. 2 is a schematic plan view of the semiconductor device according to the first embodiment. Fig. 3 is a schematic cross-sectional view of the semiconductor device according to the first embodiment. Fig. 4 is a schematic cross-sectional view of a semiconductor device according to a second embodiment. Fig. 5 is a schematic plan view of the semiconductor device according to the second embodiment. Fig. 6 is a schematic cross-sectional view of the semiconductor device according to a first variant of the second embodiment. Fig. 7 is a schematic plan view of the semiconductor device according to the first variant of the second embodiment. Fig. 8 is a schematic cross-sectional view of the semiconductor device according to a second variant of the second embodiment. Fig. 9 is a schematic plan view of the semiconductor device according to the second variant of the second embodiment. Fig. 10 is a schematic cross-sectional view of the semiconductor device according to a third variant of the second embodiment. Fig. 11 is a schematic plan view of the semiconductor device according to the third variant of the second embodiment. DESCRIPTION OF THE PREFERRED EMBODIMENTS <einleitung>

[0009] In a direction parallel to a depth direction of a semiconductor device, one side is expressed as "top" and the other side is expressed as "bottom." In two main surfaces of a substrate, layer, or other member, one surface is called an upper surface and the other surface is called a lower surface. The "top" and "bottom" directions are not limited to the direction of gravity or the direction at the time of mounting the semiconductor device.

[0010] The drawings are illustrated schematically, and the correlation between the size and position in each of the images shown in various drawings is not necessarily specified precisely, but may be changed as needed. In the following description, similar components are denoted by the same reference numerals for illustrative purposes and are also considered to have similar names and functions. Thus, detailed descriptions of such components may not be repeated. First embodiment

[0011] A first embodiment will be described below with reference to the drawings. Fig. 1 is a schematic cross-sectional view of a semiconductor device 100 according to the first embodiment. Fig. 2 is a schematic plan view of the semiconductor device 100 according to the first embodiment. Fig. Figure 1 illustrates a cross section along the dotted line XX in Fig. 2. In Fig. 1, for the sake of simplicity of explanation, a fastening section 6, a fastening element 7 and a spacer 22 are shown in addition to the cross section along the dot-dash line XX in Fig. 2. The spacer 22 is in Fig. 2 indicated by the dotted line.

[0012] A configuration of the semiconductor device 100 will be described with reference to Fig. 1 and Fig. 2. As described in Fig. 1, the semiconductor device 100 includes a semiconductor module 10, a heat sink 20 including a mounting surface 21 over which the semiconductor module 10 is mounted, and a heat dissipation member 30 interposed between a heat dissipation plate 1 of the semiconductor module 10 and the heat sink 20. First, a detailed configuration of the semiconductor module 10 will be described with reference to Fig. 1. The semiconductor module 10 comprises the heat dissipation plate 1 and an insulation plate 2.

[0013] The heat dissipation plate 1 is made of a material that exhibits electrical conductivity and thermal conductivity. For example, the heat dissipation plate 1 is made of a metal material such as copper or aluminum.

[0014] The insulating plate 2 is provided on the upper surface of the heat dissipation plate 1. The insulating plate 2 is mounted on the upper surface of the heat dissipation plate 1, for example, by soldering or the like. The insulating plate 2 is made of resin having electrical insulation properties, and is made of, for example, a ceramic.

[0015] As in Fig. As illustrated in Figure 1, a metal pattern 3 may be provided on the upper surface of the insulating plate 2. The metal pattern 3 is mounted on the upper surface of the insulating plate 2, for example, by soldering or the like. The metal pattern 3 is made of a metal having high electrical conductivity, such as copper.

[0016] As in Fig. 1, a semiconductor chip 4 is placed on the metal pattern 3. The semiconductor chip 4 may be made of Si or SiC, GaN, or Ga2O3 as a wide bandgap semiconductor. It is not particularly necessary to limit the device type of the semiconductor chip 4, which may be a switching element 4a, such as an insulated gate bipolar transistor (IGBT) or a metal oxide semiconductor field-effect transistor (MOSFET), or a freewheeling element 4b. For example, as shown in Fig. 2, the semiconductor chip 4 may consist of a plurality of switching elements 4a and a plurality of freewheeling elements 4b. As shown in Fig. As illustrated in Figure 2, the plurality of elements are arranged in the lateral direction and bonded via wires that are not illustrated. The plurality of switching elements 4a and the plurality of freewheeling elements 4b are arranged such that each switching element 4a and a respective one of the freewheeling elements 4b are arranged in the longitudinal direction. The plurality of freewheeling elements 4b are connected to the plurality of switching elements 4a in an anti-parallel manner, and current flows evenly therethrough.

[0017] Furthermore, as in Fig. 1, the semiconductor module 10 may include a housing member 5 at its outer edge. The housing member 5 is made of resin having electrical insulation properties and is bonded to the heat dissipation plate 1. As shown in Fig. 2, the housing member 5 may be provided so as to surround the outer edge of, for example, the insulating plate 2 provided on the heat dissipation plate 1.

[0018] As in Fig. 1, the semiconductor module 10 is provided with the fixing portion 6. The fixing portion 6 provided on the semiconductor module 10 is referred to as a first fixing portion 6a, and as shown in Fig. 1, in the present embodiment, the first fixing portion 6a is provided in the housing member 5. The fixing member 7 for fixing the semiconductor module 10 and the heat sink 20 to each other is attached to the fixing portion 6. Preferably, as shown in Fig. 2, the first fixing portion 6a is provided in each of the four corners at the outer edge of the semiconductor module 10.

[0019] Furthermore, as in Fig. 1, the semiconductor module 10 may be sealed with a sealing element 8. As shown in Fig. As illustrated in Figure 1, in the present embodiment, the sealing member 8 is provided on the inside of the housing member 5. The sealing member 8 is made of, for example, gel, resin, or the like, which has electrical insulation properties.

[0020] The semiconductor module 10 is configured as described above. As shown in Fig. 3, the first fixing portion 6a may be provided on the semiconductor module 10 in the heat dissipation plate 1.

[0021] With reference to Fig. 1, the heat dissipation element 30 will be described next. As in Fig. 1, the heat dissipation member 30 is provided so as to be interposed between the heat dissipation plate 1 of the semiconductor module 10 and the heat sink 20. The heat dissipation member 30 is made of a material having high thermal conductivity and flexibility, such as thermal grease or a thermal sheet. The thickness of the heat dissipation member 30 is approximately 10 μm to 100 μm in the case of a thermal sheet, and approximately 50 μm to 100 μm in the case of thermal grease as an application amount. The heat dissipation member 30 is only required to be provided at least immediately below the heat dissipation plate 1, and it is not absolutely required to be provided immediately below the casing member 5.

[0022] With reference to Fig. 1 and Fig. 2, the heat sink 20 is described in detail. As in Fig. 1, the heat sink 20 includes the mounting surface 21 over which the semiconductor module 10 is mounted, wherein the heat dissipation member 30 having flexibility is inserted. The heat sink 20 is made of metal having high thermal conductivity, such as aluminum. Further, the heat sink 20 may include a fin formed on its lower surface side. In addition, the heat sink 20 includes the fixing portion 6 to which the fixing member 7 for fixing the semiconductor module 10 and the heat sink 20 to each other is attached. The fixing portion 6 provided on the side of the heat sink 20 is referred to as a second fixing portion 6b. Further, as shown in Fig. 1, the spacer 22 is provided at the mounting portion 6 between the semiconductor module 10 and the heat sink 20. As shown in Fig. 1, the spacer 22 is preferably provided on the second attachment portion 6b and is provided in contact with the mounting surface 21 of the heat sink 20. The spacer 22 may be provided integrally with the heat sink 20. As shown in Fig. 2, the second fixing portion 6b and the spacer 22 are preferably provided in each of the four corners on the outer edge of the heat sink 20. Before being fixed by the fixing member 7, the height of the spacer 22 is less than or equal to the maximum thickness of the heat dissipation member 30. As described above, the thickness of the heat dissipation member 30 is about several tens of micrometers, and accordingly, the height of the spacer 22 is also about several tens of micrometers, which is less than or equal to the maximum thickness of the heat dissipation member 30. Thus, the heat dissipation member 30 can be brought into close contact with the mounting surface 21 of the heat sink 20 and the semiconductor module 10, and the heat dissipation performance can be ensured. As shown in FIGS. Fig. 1 and Fig. 2, the spacer 22 may be shaped like a cube or have any other shape. Preferably, as shown in the Fig. 1 and Fig. 2 illustrates the width of the spacer 22 as a width to be saved with respect to the width of the fastening element 7.

[0023] Although the spacer 22 is provided at the second attachment portion 6b on the heat sink 20 in the above description, the spacer 22 may be provided at the first attachment portion 6a on the semiconductor module 10. For example, the spacer 22 may be provided in contact with the lower surface of the case member 5 and may be provided integrally with the case member 5. When thermal grease is applied as the heat dissipation member 30 to the semiconductor module 10, it is preferable that the spacer 22 be provided in contact with the mounting surface 21 of the heat sink 20 because applying the thermal grease as the heat dissipation member 30 to the lower surface of the heat dissipation plate 1 of the semiconductor module 10 is facilitated.

[0024] As described above, the semiconductor module 10 and the heat sink 20 each include the fixing portion 6, and identical fixing members 7 are inserted into the respective fixing portions 6, and the semiconductor module 10 and the heat sink 20 are fixed to each other by the fixing member 7. The fixing portion 6 may be a screw hole, and the fixing member 7 may be a screw, a nut, or the like. As described above, the fixing portions 6 are preferably provided in the four corners on the outer edge, but they only need to be provided in at least two or more locations, and the locations and the number of the fixing portions 6 can be selected as needed depending on the size of the semiconductor device and the like. The fixing member 7 can be inserted from the lower surface side of the heat sink 20.

[0025] The semiconductor device 100 according to the present embodiment is configured as described above. The configuration in which the spacer 22 is provided at the fixing portion 6 between the semiconductor module 10 and the heat sink 20 makes it possible, when the semiconductor module 10 and the heat sink 20 are fixed to each other by the fixing member 7, to prevent the occurrence of a stress difference in the heat dissipation member 30 and to prevent a crack caused by stress in the insulating plate 2 of the semiconductor module 10 or the like. The reasons for this will be described below.

[0026] In a conventional semiconductor device, a mounting surface 21 of a heat sink 20 is flat, and accordingly, a mounting portion 6 of a semiconductor module 10 is lowered with respect to a central portion of the semiconductor module 10 located away from the mounting portion 6. Thus, a stress difference occurs in a heat dissipation member 30 between the vicinity of the mounting portion 6 and the central portion located away from the mounting portion 6. The stress difference occurring in the heat dissipation member 30 causes a crack in a member with relatively low flexibility, such as an insulating plate 2, included in the semiconductor module 10.For example, when a first fixing portion 6a is provided in the casing member 5, a crack is caused in the casing member 5, and when the first fixing portion 6a is provided in the heat dissipation plate 1, a crack is caused in the insulating plate 2.

[0027] In the semiconductor device 100 according to the present embodiment, the spacer 22 is provided at the fixing portion 6, thus making it possible to prevent, to an extent corresponding to the height of the spacer 22, the fixing portion 6 of the semiconductor module 10 from sagging relative to the central portion of the semiconductor module 10 located away from the fixing portion 6. Accordingly, in the heat dissipation member 30, a stress difference occurring between the vicinity of the fixing portion 6 and the central portion located away from the fixing portion 6 can be alleviated. As a result, a crack caused in a member with relatively low flexibility, such as the insulating plate 2 included in the semiconductor module 10, can be prevented, and the reliability of the semiconductor device can be increased.

[0028] A manufacturing method of the semiconductor device 100 according to the present embodiment will be described next. Since the manufacturing method of the semiconductor device 100 according to the present embodiment is substantially similar to a conventional semiconductor device manufacturing method except for a spacer formation step for the heat sink 20, a formation step of the semiconductor module 10 will not be described below.

[0029] The manufacturing method of the semiconductor device 100 includes the spacer forming step, a heat dissipation member forming step, and a mounting step.

[0030] First, the spacer forming step will be described. As an example of the forming method of the spacer 22, a package in which the spacer 22 is provided integrally with the heat sink 20 will be described first. In the heat sink 20 including the flat mounting surface 21, the mounting surface 21 except for the second fixing portion 6b is shaved using, for example, a micro grinder or the like. Thus, the spacer 22 can be formed on the second fixing portion 6b.

[0031] When the spacer 22 is provided as a separate member from the heat sink 20, the spacer 22 can be formed on the heat sink 20 including the mounting surface 21, which is flat, by placing it as the separate member on the second fixing portion 6b in the mounting surface 21. When the spacer 22 is provided on the first fixing portion 6a in the semiconductor module 10, the spacer 22 can be formed on the first fixing portion 6a by molding the semiconductor module 10 by the method described above.

[0032] Next, the heat dissipation member formation step will be described. The heat dissipation member 30, which has flexibility, is formed at least on the lower surface of the heat dissipation plate 1 in the semiconductor module 10. Thermal grease may be applied to the lower surface of the heat dissipation plate 1, or a thermal sheet may be attached to the lower surface of the heat dissipation plate 1.

[0033] The fastening step will be described next. First, the semiconductor module 10 is mounted over the heat sink 20 with the heat dissipation member 30 interposed therebetween. Next, the fastening member 7 is inserted into the fastening portion 6 provided between the semiconductor module 10 and the heat sink 20. After that, the heat sink 20 and the semiconductor module 10 are fastened together by the fastening member 7. Thus, the semiconductor module 10, the heat sink 20, and the heat dissipation member 30 can be brought into close contact with each other.

[0034] The semiconductor device 100 is manufactured through the above steps. As described above, the manufacturing method of the semiconductor device 100 according to the present embodiment further includes the spacer forming step, and the spacer 22 is formed on the fixing portion 6. Forming the spacer 22 in the fixing step allows it to prevent the fixing portion 6 of the semiconductor module 10 from sinking relative to the central portion of the semiconductor module 10, which is located away from the fixing portion 6, to an extent corresponding to the height of the spacer 22. Accordingly, in the heat dissipation member 30, a stress difference that occurs between the vicinity of the fixing portion 6 and the central portion, which is located away from the fixing portion 6, can be alleviated.As a result, a crack caused in a member with relatively low flexibility, such as the insulating plate 2 included in the semiconductor module 10, can be prevented, and the reliability of the semiconductor device can be increased. Second embodiment

[0035] With reference to Fig. 4 and Fig. 5, a semiconductor device 200 according to a second embodiment is described. Fig. 4 is a schematic cross-sectional view of the semiconductor device 200 according to the second embodiment. Fig. 5 is a schematic plan view of the semiconductor device 200 according to the second embodiment. Fig. Figure 4 illustrates a cross section along the dotted line XX in Fig. 5. In Fig. 4, for the convenience of explanation, a fastening section 6, a fastening element 7 and a spacer 22 are shown in addition to the cross section along the dot-dash line XX in Fig. 5. The spacer 22 and a projecting portion 23 are shown in Fig. 5 indicated by the dotted lines.

[0036] The semiconductor device 200 according to the second embodiment further includes the protruding portion 23 on a mounting surface 21 of a heat sink 20. As shown in Fig. 4 and Fig. 5, the protruding portion 23 is provided at a location on the mounting surface 21 of the heat sink 20, the location corresponding to a semiconductor chip 4. The height of the protruding portion 23 is less than or equal to the height of the spacer 22. A difference from the first embodiment is that the protruding portion 23 is further provided on the mounting surface 21 of the heat sink 20. It is only required that the protruding portion 23 be provided at least at a location on the mounting surface 21 of the heat sink 20, the location corresponding to the semiconductor chip 4, or as in Fig. 5, the protruding portion 23 may be provided only at one location on the mounting surface 21 of the heat sink 20, which location corresponds to the semiconductor chip 4. The reasons for this will be described later. For example, if sets of semiconductor chips 4, each consisting of a plurality of switching elements 4a and a plurality of freewheeling elements 4b, are provided separately at two locations, as shown in Fig. 5, the projecting portions 23 may also be provided separately only at two locations, each of which corresponds to a respective set of the plurality of switching elements 4a and the plurality of freewheeling elements 4b of the semiconductor chips 4. As shown in the Fig. 4 and Fig. As illustrated in FIG. 5, the protruding portion 23 is preferably shaped like a rectangular parallelepiped to match the shape of the semiconductor chip 4, but may have any shape. The protruding portion 23 is preferably provided integrally with the heat sink 20. Thus, compared with a case where the protruding portion 23 is provided separately on the heat sink 20, the thermal conductivity can be further secured, and the heat dissipation performance can be increased.

[0037] The semiconductor device 200 according to the second embodiment is configured as described above. Similar to the first embodiment, by adopting the configuration in which the spacer 22 is provided at the fixing portion 6 between the semiconductor module 10 and the heat sink 20, when the semiconductor module 10 and the heat sink 20 are fixed to each other by the fixing member 7, it is possible to prevent the occurrence of a stress difference in a heat dissipation member 30 and prevent a crack caused by stress in an insulating plate 2 of a semiconductor module 10 or the like.

[0038] Furthermore, by adopting the configuration in which the protruding portion 23 is provided at a location on the mounting surface 21 of the heat sink 20, the location corresponding to the semiconductor chip 4, the heat dissipation performance of the semiconductor module 10 can be improved. The reasons for this will be described below.

[0039] Heat dissipation performance is most needed immediately below the mounted semiconductor chip 4, which is a heat generation source of the semiconductor module 10. To improve heat dissipation performance, it is only necessary to increase the degree of contact between the heat dissipation plate 1 of the semiconductor module 10 and the heat dissipation member 30 and the heat sink 20 immediately below the mounted semiconductor chip 4.

[0040] In the semiconductor device 200 according to the second embodiment, the protruding portion 23 is provided at a location on the mounting surface 21 of the heat sink 20, which location corresponds to the semiconductor chip 4. Thus, the distance between the heat dissipation plate 1 and the heat sink 20 immediately below the semiconductor chip 4 is reduced, and with the reduction, the compressibility of the heat dissipation member is increased, and the contact degree can be increased accordingly. Due to the increased contact degree, the heat dissipation performance immediately below the mounted semiconductor chip 4, which is the heat generation source of the semiconductor module 10, can be improved.

[0041] The height of the protruding portion 23 mentioned above is made smaller than or equal to the height of the spacer 22. If the height of the protruding portion 23 is greater than the height of the spacer 22, when the semiconductor module 10 is fixed to the heat sink 20 with the heat dissipation member 30 inserted, a phenomenon occurs in which the fixing portion 6 of the semiconductor module 10 lowers with respect to the central portion of the semiconductor module 10 located away from the fixing portion 6, regardless of the spacer 22 provided at the fixing portion 6. As a result, a stress difference occurs in the heat dissipation member 30 between the location of the protruding portion 23 provided on the heat sink 20 and the location of the spacer 22 provided at the fixing portion 6.Accordingly, a crack is caused in the housing member 5 or the insulating plate 2, which has relatively low flexibility, and reliability is reduced. Thus, by making the height of the protruding portion 23 less than or equal to the height of the spacer 22, the occurrence of a stress difference between the location of the protruding portion 23 and the location of the spacer 22 in the heat dissipation member 30 can be prevented. Consequently, the heat dissipation performance can be secured while preventing the occurrence of a crack in the housing member 5 or a crack in the insulating plate 2, while maintaining reliability.

[0042] With reference to Fig. 6 to Fig. 11, variants of the second embodiment will be described next. First, the first variant will be described with reference to Fig. 6 and Fig. 7 described. Fig. 6 is a schematic cross-sectional view of the semiconductor device according to the first variant. Fig. 7 is a schematic plan view of the semiconductor device according to the first variant. Fig. Figure 6 illustrates a cross section along the dotted line XX in Fig. 7. In Fig. 6, for the sake of simplicity of explanation, the fastening section 6, the fastening element 7 and the spacer 22 are shown in addition to the cross section along the dot-dash line XX in Fig. 7. The spacer 22 and the projecting portion 23 are shown in Fig. 7 indicated by the dotted lines.

[0043] As in Fig. 6, the protruding portion 23 may be provided to become higher toward the central portion of the semiconductor module 10. The maximum height of the protruding portion 23 is made smaller than the height of the spacer 22. As shown in Fig. 6, the above section 23 may be provided in a stepped form. As shown in Fig. 6, in the protruding portion 23 provided in a stepped form, the starting point of each level difference of the steps can be made to coincide with a side surface on the outer edge side of a corresponding one of the semiconductor chips 4.

[0044] The plurality of semiconductor chips 4 placed in the semiconductor module 10 each receive thermal interference due to the heat generation of the other semiconductor chips 4 located around them. Thus, the semiconductor chip 4 located closer to the central portion of the semiconductor module 10 becomes higher in temperature and is required to have higher heat dissipation performance.

[0045] Since the semiconductor device according to the first variation is provided such that the protruding portion 23 becomes higher toward the central portion of the semiconductor module 10, the degree of contact between the heat dissipation plate 1 of the semiconductor module 10 and the heat dissipation member 30 and the heat sink 20 increases toward the central portion of the semiconductor module 10. Thus, the heat dissipation performance can be selectively improved toward the central portion of the module where the temperature becomes higher.

[0046] With reference to Fig. 8 and Fig. 9 the second variant is described next. Fig. 8 is a schematic cross-sectional view of the semiconductor device according to the second variant. Fig. 9 is a schematic plan view of the semiconductor device according to the second variant. Fig. Figure 8 illustrates a cross section along the dotted line XX in Fig. 9. In Fig. 8, for the sake of simplicity of explanation, the fastening section 6, the fastening element 7 and the spacer 22 are shown in addition to the cross section along the dot-dash line XX in Fig. 9. The spacer 22 and the projecting portion 23 are shown in Fig. 9 indicated by the dotted lines.

[0047] As in Fig. 8, in the semiconductor device according to the second variation, the protruding portion 23 is provided to become higher toward the central portion of the semiconductor module 10, similar to the first variation. Further, as shown in Fig. 8 and Fig. As illustrated in FIG. 9, in the semiconductor device according to the second variation, the protruding portion 23 is provided only at the locations corresponding to the plurality of semiconductor chips 4, respectively. The maximum height of the protruding portion 23 is made smaller than the height of the spacer 22.

[0048] Since the semiconductor device according to the second variation is provided similarly to the semiconductor device according to the first variation, such that the protruding portion 23 becomes higher toward the central portion of the semiconductor module 10, the degree of contact between the heat dissipation plate 1 of the semiconductor module 10 and the heat dissipation member 30 and the heat sink 20 increases toward the central portion of the semiconductor module 10. Thus, the heat dissipation performance can be selectively improved toward the central portion of the module where the temperature becomes higher.

[0049] Furthermore, in the semiconductor device according to the second variation, the protruding portion 23 is provided only at the locations corresponding to the plurality of semiconductor chips 4, respectively. Due to the fixing, the heat dissipation member 30 is further compressed at the location where the protruding portion 23 is provided. Thus, when the area of ​​the protruding portion 23 provided on the mounting surface 21 of the heat sink 20 is wider, the heat dissipation member 30 is further compressed, and greater stress is caused in the heat dissipation member 30. However, by providing the protruding portion 23 only at the locations corresponding to the plurality of semiconductor chips 4, the stress caused in the heat dissipation member 30 can be further suppressed compared to the first variation, and the heat dissipation performance can be maintained even immediately under the semiconductor chip 4.

[0050] With reference to Fig. 10 and Fig. 11 the third variant is described next. Fig. 10 is a schematic cross-sectional view of the semiconductor device according to the third variant. Fig. 11 is a schematic plan view of the semiconductor device according to the third variant. Fig. Figure 10 illustrates a cross section along the dotted line XX in Fig. 11. In Fig. 10, for the sake of simplicity of explanation, the fastening section 6, the fastening element 7 and the spacer 22 are shown in addition to the cross section along the dot-dash line XX in Fig. 11. The spacer 22 and the projecting portion 23 are shown in Fig. 11 indicated by the dotted lines.

[0051] As in Fig. 10 and Fig. As illustrated in FIG. 11, in the semiconductor device according to the third variation, similarly to the semiconductor device according to the second variation, the protruding portion 23 is provided to become higher toward the central portion of the semiconductor module 10 and is provided only at the locations corresponding to the plurality of semiconductor chips 4, respectively. Further, in the semiconductor device according to the third variation, the upper surface of the protruding portion 23 is made smaller in size than the lower surface of the semiconductor chip 4. The maximum height of the protruding portion 23 is made smaller than the height of the spacer 22.

[0052] Since the semiconductor device according to the third variation is provided similarly to the semiconductor devices according to the first variation and the second variation, such that the protruding portion 23 becomes higher toward the central portion of the semiconductor module 10, the degree of contact between the heat dissipation plate 1 of the semiconductor module 10 and the heat dissipation member 30 and the heat sink 20 increases toward the central portion of the semiconductor module 10. Thus, the heat dissipation performance can be selectively improved toward the central portion of the module where the temperature becomes higher.

[0053] Furthermore, in the semiconductor device according to the third variation, similar to the semiconductor device according to the second variation, the protruding portion 23 is provided only at the locations corresponding to the plurality of semiconductor chips 4, respectively. Thus, the stress caused in the heat dissipation member 30 can be suppressed, and the heat dissipation performance can be maintained even immediately below the semiconductor chip 4.

[0054] Furthermore, in the semiconductor device according to the third variation, the upper surface of the protruding portion 23 is made smaller in size than the lower surface of the semiconductor chip 4. Thus, the stress caused in the heat dissipation member 30 can be further suppressed. The size of the upper surface of the protruding portion 23 is preferably made small so that its lower limit is 80% of the size of the lower surface of the semiconductor chip 4. If the upper surface of the protruding portion 23 is made much smaller in size than the lower surface of the semiconductor chip 4, the contact area immediately below the semiconductor chip 4 is reduced, and the heat dissipation performance is correspondingly reduced.Thus, by reducing the size of the upper surface of the protruding portion 23 so that its lower limit is 80% of the size of the lower surface of the semiconductor chip 4, it is possible to further suppress the stress caused in the heat dissipation member 30 while maintaining the heat dissipation performance. As shown in FIG. Fig. 11, the upper surface of the projecting portion 23 may be shaped like a cross.

[0055] The configurations described above in the embodiments are presented as examples of the features of the present disclosure and can be combined with other known techniques. Furthermore, the embodiments and variants can be combined with each other. Furthermore, the configurations may be partially omitted or changed within the scope without deviating from the gist of the present disclosure. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2024-037299

[0001] JP 2023-000129 [0004, 0005]< / einleitung>

Claims

[1] A semiconductor device (100, 200) comprising: a semiconductor module (10) comprising a heat dissipation plate (1); a heat sink (20) comprising a mounting surface (21) over which the semiconductor module (10) is mounted; a heat dissipation element (30) inserted between the heat dissipation plate (1) and the heat sink (20) and having flexibility; and a spacer (22), wherein the semiconductor module (10) and the heat sink (20) are fastened to one another by a fastening element (7), the semiconductor module (10) and the heat sink (20) each comprise a fastening section (6a, 6b) to which the fastening element (7) is attached, and the spacer (22) is provided on the fixing portion (6a) of the semiconductor module (10) or the fixing portion (6b) of the heat sink (20). [2] The semiconductor device (100, 200) according to claim 1, wherein a height of the spacer (22) is less than or equal to a maximum thickness of the heat dissipation member (30) before mounting. [3] The semiconductor device (100, 200) according to claim 1 or 2, wherein the spacer (22) is provided in contact with the mounting surface (21) of the heat sink (20). [4] The semiconductor device (100, 200) according to claim 3, wherein the spacer (22) is provided integrally with the heat sink (20). [5] Semiconductor device (100, 200) according to one of claims 1-4, wherein the semiconductor module (10) comprises a housing element (5) on an outer edge of the semiconductor module (10), and the fixing portion (6a) of the semiconductor module (10) is provided in the housing element (5). [6] The semiconductor device (100) according to any one of claims 1-4, wherein the fixing portion (6a) of the semiconductor module (10) is provided in the heat dissipation plate (1). [7] The semiconductor device (100, 200) according to any one of claims 1-6, wherein the fixing portion (6a, 6b) is provided at each of at least two or more locations. [8] A semiconductor device (200) according to claim 1, wherein the semiconductor module (10) comprises a semiconductor chip (4), the heat sink (20) comprises a protruding portion (23) provided at a location on the mounting surface (21), the location corresponding to the semiconductor chip (4), and a height of the projecting portion (23) is less than or equal to a height of the spacer (22). [9] The semiconductor device (200) according to claim 8, wherein the protruding portion (23) is provided to become higher toward a central portion of the semiconductor module (10). [10] The semiconductor device (200) according to claim 9, wherein the protruding portion (23) is provided in a stepped shape. [11] The semiconductor device (200) according to claim 8 or 9, wherein the protruding portion (23) is provided only at the position corresponding to the semiconductor chip (4). [12] The semiconductor device (200) according to claim 11, wherein an upper surface of the protruding portion (23) is smaller in size than a lower surface of the semiconductor chip (4). [13] Heat sink (20), comprising: a mounting surface (21) over which a semiconductor module (10) is to be mounted, wherein a heat dissipation element (30) having flexibility is inserted; a fixing portion (6b) to which a fixing member (7) for fixing the semiconductor module (10) and the heat sink (20) to each other is to be attached, the fixing portion (6b) being provided on the mounting surface (21); and a spacer (22) provided on the fixing portion (6b). [14] The heat sink (20) according to claim 13, wherein a height of the spacer (22) is less than or equal to a maximum thickness of the heat dissipation member (30) before fastening. [15] The heat sink (20) according to claim 13 or 14, wherein the fixing portion (6b) is provided at each of at least two or more locations. [16] Heat sink (20) according to claim 13, wherein the semiconductor module (10) comprises a semiconductor chip (4), and the heat sink (20) further comprises a protruding portion (23) provided at a location of the mounting surface (21), the location corresponding to the semiconductor chip (4), wherein a height of the protruding portion (23) is less than or equal to a height of the spacer (22). [17] The heat sink (20) according to claim 16, wherein the protruding portion (23) is provided to become higher toward a central portion of the semiconductor module (10). [18] The heat sink (20) according to claim 17, wherein the protruding portion (23) is provided in a stepped shape. [19] The heat sink (20) according to claim 16 or 17, wherein the protruding portion (23) is provided only at the position corresponding to the semiconductor chip (4). [20] The heat sink (20) according to claim 19, wherein an upper surface of the protruding portion (23) is smaller in size than a lower surface of the semiconductor chip (4).

Images