Semiconductor module and heat dissipation plate

Abstract

A semiconductor module (1) is provided with a heat dissipation plate (20) and a semiconductor element (10). The heat dissipation plate (20) has a first heat dissipation part (21) and a second heat dissipation part (22) formed from a material having anisotropic thermal conductivity. The first heat dissipation section (21) is provided so as to include a position facing the semiconductor element (10) in the thickness direction of the heat dissipation plate (20), and has high thermal conductivity in the in-plane direction of an arbitrary first virtual plane parallel to the thickness direction of the heat dissipation plate (20). The second heat dissipation part (22) is connected to the first heat dissipation part (21) in a direction parallel to the in-plane direction of the first virtual plane and perpendicular to the thickness direction of the heat dissipation plate (20), and has high thermal conductivity in the in-plane direction of a second virtual plane perpendicular to the thickness direction of the heat dissipation plate (20).

Description

Technical Field

[0001] The present disclosure relates to a semiconductor module and a heat sink used therefor. Background Art

[0002] The semiconductor module described in Patent Document 1 includes a semiconductor element and a heat sink for dissipating the heat generated by the semiconductor element. In addition, in Patent Document 1, the heat sink is referred to as a radiator. The heat sink of Patent Document 1 includes a first heat sink and a second heat sink formed of graphite, which is a material having anisotropy in thermal conductivity, and is formed into a quadrilateral shape when viewed from the thickness direction. The first heat sink has high thermal conductivity in the in-plane direction of an arbitrary virtual surface parallel to the plate thickness direction of the heat sink. The second heat sink is connected to the first heat sink in a direction perpendicular to the arbitrary virtual surface, and has high thermal conductivity in the in-plane direction of another virtual surface perpendicular to the arbitrary virtual surface. The semiconductor element is configured to overlap both the first heat sink and the second heat sink. As a result, the heat generated from the semiconductor element diffuses into the heat sink via the first heat sink and the second heat sink, and the heat is dissipated from the surface of the heat sink on the opposite side of the semiconductor element.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-100401 Summary of the invention

[0006] However, the semiconductor module described in Patent Document 1 has a structure in which it is difficult for the heat generated by the semiconductor element to be transferred to the four corners of the quadrilateral heat sink due to the anisotropy of the thermal conductivity of the first heat sink and the second heat sink and their arrangement. Therefore, the semiconductor module cannot effectively use the entire area of ​​the heat sink, and there is room for improvement.

[0007] In view of the above-mentioned problems, an object of the present disclosure is to provide a semiconductor module and a heat sink capable of improving heat dissipation.

[0008] According to one viewpoint of the present disclosure, a semiconductor module includes a plate-shaped heat sink and a semiconductor element that is arranged in the thickness direction of the heat sink and generates heat when powered. The heat sink includes a first heat sink and a second heat sink that are formed of a material having anisotropy in thermal conductivity. The first heat sink is provided at a position opposite to the semiconductor element in the thickness direction of the heat sink, and has a higher thermal conductivity in the in-plane direction of any first virtual surface parallel to the thickness direction of the heat sink than in the direction perpendicular to the in-plane direction of the first virtual surface. The second heat sink is connected to the first heat sink in a direction parallel to the in-plane direction of the first virtual surface and perpendicular to the thickness direction of the heat sink, and has a higher thermal conductivity in the in-plane direction of the second virtual surface perpendicular to the thickness direction of the heat sink than in the direction perpendicular to the in-plane direction of the second virtual surface.

[0009] Accordingly, the heat transferred from the semiconductor element to the first heat dissipation part diffuses in the in-plane direction of the first virtual surface at the position of the first heat dissipation part opposite to the semiconductor element. Therefore, a part of the heat transferred from the semiconductor element to the first heat dissipation part is dissipated from the surface of the first heat dissipation part on the side opposite to the semiconductor element, and the remaining part is transferred to the second heat dissipation part. The heat transferred to the second heat dissipation part diffuses in the second heat dissipation part in the in-plane direction of the second virtual surface perpendicular to the thickness direction of the heat sink. Therefore, the heat diffuses in the second heat dissipation part and is transferred from the second heat dissipation part to a position of the first heat dissipation part different from the position opposite to the semiconductor element. The heat transferred from the second heat dissipation part to the first heat dissipation part diffuses in the in-plane direction of the first virtual surface in the first heat dissipation part and is dissipated from the surface of the first heat dissipation part on the side opposite to the semiconductor element.

[0010] Thus, by providing the second heat dissipation portion functioning as a heat direction conversion portion outside the first heat dissipation portion, the heat generated by the semiconductor element can be diffused to substantially the entire area of ​​the heat dissipation plate and dissipated in the thickness direction of the heat dissipation plate. Therefore, the semiconductor module can increase the area of ​​the heat dissipation plate functioning as a heat dissipation surface and improve the heat dissipation performance of the heat dissipation plate.

[0011] In addition, "vertical" in the present disclosure includes a substantially vertical state such as a manufacturing error, and "parallel" includes a substantially parallel state such as a manufacturing error. In addition, in the present disclosure, "the heat dissipation portion has high thermal conductivity in the in-plane direction of the specified virtual surface" means that in the heat dissipation portion, the thermal conductivity in the in-plane direction of the specified virtual surface is greater than the thermal conductivity in the direction perpendicular to the specified virtual surface. In addition, the heat dissipation plate only needs to have at least the first heat dissipation portion and the second heat dissipation portion, and may also have other heat dissipation portions.

[0012] Another aspect of the present disclosure relates to a plate-shaped heat sink for dissipating heat generated by a semiconductor element used in a semiconductor module. The semiconductor element is arranged in the thickness direction of the heat sink. The heat sink has a first heat sink and a second heat sink formed of a material having anisotropy in thermal conductivity. The first heat sink is provided at a position opposite to the semiconductor element in the thickness direction, and has a higher thermal conductivity in the in-plane direction of any first virtual surface parallel to the thickness direction than in the direction perpendicular to the in-plane direction of the first virtual surface. The second heat sink is connected to the first heat sink in a direction parallel to the in-plane direction of the first virtual surface and perpendicular to the thickness direction, and has a higher thermal conductivity in the in-plane direction of the second virtual surface perpendicular to the thickness direction than in the direction perpendicular to the in-plane direction of the second virtual surface.

[0013] According to this, the heat sink of another aspect can diffuse the heat generated by the semiconductor element to substantially the entire area of ​​the heat sink and dissipate the heat in the thickness direction of the heat sink as described in the first aspect. Therefore, the semiconductor module using the heat sink can improve the heat dissipation performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a perspective view of the semiconductor module and the cooler according to the first embodiment.

[0015] Figure 2 yes Figure 1 A top view of the semiconductor module viewed in direction II.

[0016] Figure 3 is a schematic diagram showing the molecular structure of graphite.

[0017] Figure 4 It is a top view of the semiconductor module of the first comparative example.

[0018] Figure 5 It is an explanatory diagram for explaining the way in which heat is transferred when a semiconductor element generates heat in the semiconductor module of the first comparative example.

[0019] Figure 6 It is an explanatory diagram for explaining the way of heat transfer when the semiconductor element generates heat in the semiconductor module of the second comparative example.

[0020] Figure 7 It is a perspective view of a semiconductor module according to the second embodiment.

[0021] Figure 8 yes Figure 7 A top view of the semiconductor module viewed in direction VIII.

[0022] Fig. 9 It is a perspective view of a semiconductor module according to a third embodiment.

[0023] Fig.10 yes Fig. 9 A top view of the semiconductor module viewed in the X direction.

[0024] Fig.11 It is a top view of a semiconductor module according to a fourth embodiment.

[0025] Fig.12 It is a top view of the semiconductor module according to the fifth embodiment.

[0026] Fig.13 It is a top view of a semiconductor module according to the sixth embodiment.

[0027] Fig.14 It is a top view of the semiconductor module according to the seventh embodiment.

[0028] Fig.15 It is a top view of a semiconductor module according to the eighth embodiment.

[0029] Fig.16 It is a perspective view of a semiconductor module according to a ninth embodiment.

[0030] Fig.17 It is a perspective view of a semiconductor module according to a tenth embodiment.

[0031] Fig.18 It is a perspective view of a semiconductor module according to the eleventh embodiment.

[0032] Fig.19 It is a perspective view of a semiconductor module according to a twelfth embodiment.

[0033] Fig. 20 It is a top view of a semiconductor module according to a thirteenth embodiment.

[0034] Fig.21 It is a top view of a semiconductor module according to a fourteenth embodiment.

[0035] Fig. 22 It is a perspective view of a semiconductor module according to a fifteenth embodiment.

[0036] Fig.23 This is a diagram analyzing the temperature distribution when the semiconductor element generates heat in the top view of the semiconductor module according to the fifteenth embodiment.

[0037] Fig.24 It is along Fig.23 A diagram analyzing the temperature distribution when a semiconductor element generates heat in a cross-sectional view taken along line XXIV-XXIV of FIG.

[0038] Fig.25 It is a perspective view of a semiconductor module according to a third comparative example.

[0039] Fig.26This is a diagram analyzing the temperature distribution when the semiconductor element generates heat in a plan view of the semiconductor module of the third comparative example.

[0040] Fig. 27 It is along Fig.26 A diagram analyzing the temperature distribution when a semiconductor element generates heat in a cross-sectional view taken along line XXVII-XXVII.

[0041] Fig.28 It is a perspective view of a semiconductor module according to the sixteenth embodiment.

[0042] Fig.29 This is a cross-sectional view parallel to the thickness direction of the heat sink in the semiconductor module according to the seventeenth embodiment.

[0043] Fig.30 It is a perspective view of a semiconductor module according to the eighteenth embodiment.

[0044] Fig.31 This is a cross-sectional view parallel to the thickness direction of the heat sink in the semiconductor module according to the eighteenth embodiment.

[0045] Fig.32 This is a cross-sectional view parallel to the thickness direction of the heat sink in the semiconductor module according to the nineteenth embodiment.

[0046] Fig.33 It is a perspective view of a semiconductor module and a cooler according to the twentieth embodiment.

[0047] Fig.34 yes Fig.33 A top view of the semiconductor module viewed in direction XXXIV. DETAILED DESCRIPTION

[0048] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, identical or equivalent parts are denoted by the same reference numerals, and description thereof will be omitted.

[0049] (First embodiment)

[0050] The first embodiment will be described with reference to the accompanying drawings. Figure 1 as well as Figure 2 As shown, the semiconductor module 1 according to the first embodiment includes a semiconductor element 10 , a heat sink 20 , and the like.

[0051] The semiconductor element 10 is a heating element that generates heat by passing electricity, such as a power semiconductor element such as a diode, MOSFET, IGBT, etc. In addition, MOSFET is the abbreviation of Metal-Oxide-Semiconductor Field Effect Transistor, and IGBT is the abbreviation of Insulated Gate Bipolar Transistor. Power semiconductor elements are formed of, for example, silicon (Si), silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga2O3), etc. The semiconductor element 10 is provided on a surface of the heat sink 20 facing the thickness direction (hereinafter referred to as the "element mounting side").

[0052] The heat sink 20 is formed in a plate shape. On the surface of the heat sink 20 opposite to the element mounting side (hereinafter referred to as the "cooling surface"), for example, a cooler 30 is arranged. In addition, a radiator or a heat exchanger may be arranged instead of or together with the cooler 30. The heat generated by the semiconductor element 10 is diffused to the heat sink 20 and dissipated from the cooling surface.

[0053] The heat sink 20 has a first heat sink 21, a second heat sink 22, and a third heat sink 23. In the description of the first embodiment and the drawings referred to in the description, letter symbols R and L indicating the positions of the respective heat sinks are added to the end of the numerals 22 and 23 indicating the second heat sink 22 and the third heat sink 23. This is also the case in the description of the fourth to twelfth and fifteenth to twentieth embodiments described later and the drawings referred to in the description.

[0054] In the first embodiment, two second heat sinks 22R and 22L and two third heat sinks 23R and 23L are arranged on the right and left sides of the drawing across the first heat sink 21. The first heat sink 21, the second heat sink 22, and the third heat sink 23 are all formed of a material having anisotropy in thermal conductivity. The material having anisotropy in thermal conductivity is, for example, graphite.

[0055] like Figure 3 As shown in FIG. 1 , the molecular structure of graphite 2 is a structure in which a plurality of graphenes 3 are stacked in a two-dimensional manner and a hexagonal lattice structure bonded with carbon atoms is extended. The thermal conductivity of the graphene 3 of graphite 2 in the in-plane direction is higher than the thermal conductivity of the plurality of graphenes 3 in the stacking direction. Specifically, graphite 2 has a Figure 3In the three-dimensional coordinates based on the a-axis, b-axis, and c-axis shown, the thermal conductivity is high in the in-plane direction of the ab plane, and low in the direction in which the c-axis extends (hereinafter referred to as the "c direction"). Generally speaking, the thermal conductivity of graphite 2 in the in-plane direction of the ab plane is about 1700 W / m·K, and the thermal conductivity in the c direction is about 7 W / m·K. In addition, the thermal conductivity of copper, which is generally used as a heat dissipation material, is about 400 W / m·K. Therefore, by utilizing the anisotropy of the thermal conductivity of graphite 2, a heat dissipation plate 20 with higher heat dissipation performance than a copper plate can be formed.

[0056] exist Figure 1 as well as Figure 2 In FIG. 1 , the layers of a plurality of graphenes 3 constituting the graphite 2 in the first heat dissipation portion 21 , the second heat dissipation portion 22 , and the third heat dissipation portion 23 are schematically indicated by dotted lines. Figure 1 as well as Figure 2 In FIG. 1 , the boundary between the first heat dissipation portion 21 , the second heat dissipation portion 22 and the third heat dissipation portion 23 is indicated by a solid line, but in fact, the first heat dissipation portion 21 , the second heat dissipation portion 22 and the third heat dissipation portion 23 are formed integrally. Figure 1 as well as Figure 2 The three-dimensional coordinates based on the X-axis, Y-axis, and Z-axis are shown so that the direction in which the Z-axis extends is consistent with the thickness direction of the heat sink 20. In addition, the direction in which the first heat sink 21, the second heat sink 22, and the third heat sink 23 are arranged is consistent with the direction in which the X-axis extends. In the following description, the direction in which the X-axis extends is referred to as the "X direction", the direction in which the Y-axis extends is referred to as the "Y direction", and the direction in which the Z-axis extends is referred to as the "Z direction". These situations are also the same in the descriptions of the second to twentieth embodiments and the first to third comparative examples described later and in the respective drawings referred to in the descriptions.

[0057] like Figure 1 as well as Figure 2 As shown, the first heat dissipation portion 21 is a portion provided at a position opposite to the semiconductor element 10 in the thickness direction of the heat dissipation plate 20. In the following description, the position of the first heat dissipation portion 21 opposite to the semiconductor element 10 in the thickness direction of the heat dissipation plate 20 is referred to as "a position directly below the semiconductor element 10 in the first heat dissipation portion 21".

[0058] The first heat dissipation portion 21 has high thermal conductivity in the in-plane direction of the first virtual plane, which is an arbitrary plane parallel to the thickness direction of the heat dissipation plate 20. In the first embodiment, the first virtual plane is the XZ plane. Therefore, the first heat dissipation portion 21 has high thermal conductivity in the in-plane direction of the XZ plane. In addition, the first heat dissipation portion 21 has a portion extending from the position directly below the semiconductor element 10 in a direction perpendicular to the in-plane direction of the first virtual plane in addition to the position directly below the semiconductor element 10.

[0059] The second heat dissipation portion 22 is a portion connected to the first heat dissipation portion 21 in a direction parallel to the in-plane direction of the first virtual plane and perpendicular to the thickness direction. Specifically, the second heat dissipation portion 22 is a portion connected to the first heat dissipation portion 21 in the X direction. More specifically, the second heat dissipation portion 22 is connected to a portion of the first heat dissipation portion 21 extending in a direction parallel to the in-plane direction of the first virtual plane and perpendicular to the thickness direction of the heat sink relative to the position directly below the semiconductor element 10. Furthermore, the second heat dissipation portion 22 is also connected to a portion of the first heat dissipation portion 21 extending in a direction perpendicular to the in-plane direction of the first virtual plane relative to the position directly below the semiconductor element 10. That is, the second heat dissipation portion 22 is connected to a portion of the first heat dissipation portion 21 in the X direction relative to the position directly below the semiconductor element 10, and is also connected to a portion of the first heat dissipation portion 21 extending from the position directly below the semiconductor element 10 in the Y direction in the X direction.

[0060] In the first embodiment, the heat sink 20 has two second heat sinks 22. Of the two second heat sinks 22, the one disposed on one side in the X direction relative to the first heat sink 21 is referred to as one second heat sink 22R, and the one disposed on the other side in the X direction relative to the first heat sink 21 is referred to as the other second heat sink 22L.

[0061] The second heat dissipation portion 22 has high thermal conductivity in the in-plane direction of the second virtual plane perpendicular to the thickness direction of the heat dissipation plate 20. In the first embodiment, the second virtual plane is the XY plane. Therefore, the second heat dissipation portion 22 has high thermal conductivity in the in-plane direction of the XY plane.

[0062] The third heat dissipation portion 23 is a portion connected to the second heat dissipation portion 22 in an arbitrary direction parallel to the in-plane direction of the second virtual plane. In the first embodiment, the first heat dissipation portion 21, the second heat dissipation portion 22, and the third heat dissipation portion 23 are arranged in the X direction. Therefore, the third heat dissipation portion 23 is a portion connected to the second heat dissipation portion 22 along the X direction. In the first embodiment, the heat sink 20 has two third heat dissipation portions 23. Of the two third heat dissipation portions 23, the one disposed on the X direction relative to the second heat dissipation portion 22R on one side is referred to as the third heat dissipation portion 23R on one side, and the one disposed on the other side in the X direction relative to the second heat dissipation portion 22L on the other side is referred to as the third heat dissipation portion 23L on the other side.

[0063] Here, a surface that is not perpendicular to the direction in which the third heat dissipation portion 23 is connected to the second heat dissipation portion 22 and is parallel to the thickness direction of the heat dissipation plate 20 is referred to as a third virtual surface. The third heat dissipation portion 23 has high thermal conductivity in the in-plane direction of the third virtual surface. In the first embodiment, the third virtual surface is a surface that is parallel to the direction in which the third heat dissipation portion 23 is connected to the second heat dissipation portion 22 and is parallel to the thickness direction of the heat dissipation plate 20. Therefore, the third virtual surface is the same as the first virtual surface, that is, the XZ surface. Therefore, the third heat dissipation portion 23 has high thermal conductivity in the in-plane direction of the XZ surface.

[0064] exist Figure 2 In FIG. 1 , a part of the path along which the heat generated from the semiconductor element 10 is transferred in the heat sink 20 is schematically indicated by arrows.

[0065] After the heat generated from the semiconductor element 10 is transferred to the position directly below the semiconductor element 10 in the first heat dissipation portion 21, as shown in FIG. Figure 2 As shown by arrow T1, the heat is transferred from this position to the second heat dissipation portion 22 located in the X direction. Then, the heat is diffused along the XY plane in the second heat dissipation portion 22. In addition, although arrows are omitted, a part of the heat transferred from the semiconductor element 10 to the position directly below the semiconductor element 10 in the first heat dissipation portion 21 is diffused along the XZ plane at the position directly below the semiconductor element 10 in the first heat dissipation portion 21, and is dissipated from the cooling surface of the first heat dissipation portion 21.

[0066] As shown by arrow T2, part of the heat diffused along the XY plane in the second heat dissipating portion 22 is transferred to the third heat dissipating portion 23. Then, the heat diffuses along the XZ plane in the third heat dissipating portion 23 and is dissipated from the cooling surface of the third heat dissipating portion 23.

[0067] In addition, as indicated by arrow T3, another part of the heat diffused along the XY plane in the second heat dissipating portion 22 is transferred to the portion of the first heat dissipating portion 21 extending in the Y direction relative to the position directly below the semiconductor element 10. Then, the heat is diffused along the XZ plane in the portion of the first heat dissipating portion 21 extending in the Y direction relative to the position directly below the semiconductor element 10, and is dissipated from the cooling surface of the first heat dissipating portion 21.

[0068] Thus, in the first embodiment, by using the second heat dissipation portion 22 as a heat direction conversion portion, the heat generated by the semiconductor element 10 can be diffused to substantially the entire area of ​​the heat dissipation plate 20 and dissipated from the cooling surface of the heat dissipation plate 20. Therefore, the semiconductor module 1 can increase the area in which the heat dissipation plate 20 functions as a heat dissipation surface, thereby improving the heat dissipation performance of the heat dissipation plate 20.

[0069] Next, semiconductor modules according to a first comparative example and a second comparative example will be described for comparison with the semiconductor module 1 described in the first embodiment.

[0070] (Comparative Example 1)

[0071] like Figure 4 As shown in FIG. 1 , the semiconductor module 101 of the first comparative example includes a heat sink 20 having four heat dissipation portions arranged radially around the semiconductor element 10. For convenience of explanation, the four heat dissipation portions are arranged relative to the semiconductor element 10. Figure 4 The heat dissipation portion on the right side of the paper is referred to as the right heat dissipation portion 41, which is arranged relative to the semiconductor element 10. Figure 4 The heat dissipation portion on the left side of the paper is referred to as the left heat dissipation portion 42. Figure 4 The heat dissipation portion on the upper side of the paper is referred to as an upper heat dissipation portion 43, which is arranged relative to the semiconductor element 10. Figure 4 The heat dissipation portion on the lower side of the paper is referred to as the lower heat dissipation portion 44. Figure 4 as well as Figure 5 In FIG. 1 , a portion located below the semiconductor element 10 among the boundaries of the four heat dissipating portions 41 to 44 is indicated by a dashed line.

[0072] The right heat sink 41 and the left heat sink 42 have high thermal conductivity in the in-plane direction of the XZ plane. The upper heat sink 43 and the lower heat sink 44 have high thermal conductivity in the in-plane direction of the YZ plane.

[0073] like Figure 5 In FIG. 1 , a part of the path of heat generated from the semiconductor element 10 and transferred to the heat sink 20 is schematically indicated by arrows.

[0074] like Figure 5 As shown by arrow T4, the heat generated from the semiconductor element 10 is transferred in the right heat dissipation portion 41 and the left heat dissipation portion 42 along the X direction within the width of the semiconductor element 10. Figure 5 As shown by arrow T5, the heat generated from the semiconductor element 10 is transferred in the Y direction within the width of the semiconductor element 10 in the upper heat dissipation portion 43 and the left heat dissipation portion 42. Figure 5 As indicated by the middle hatched line LT, a region where heat is hardly transferred is formed outside the region where heat is transferred in the X and Y directions within the width of the semiconductor element 10. Therefore, the semiconductor module 101 of the first comparative example cannot effectively utilize the entire region of the heat sink 20.

[0075] (Comparative Example 2)

[0076] like Figure 6As shown in FIG. 1 , the semiconductor module 102 of the second comparative example has the same structure as that of the above-mentioned Patent Document 1. The heat sink 20 provided in the semiconductor module 102 of the second comparative example has three heat dissipation parts. For the sake of convenience, the heat dissipation part that includes the position directly below the semiconductor element 10 and extends in the Y direction among the three heat dissipation parts is referred to as the longitudinal heat dissipation part 45. Figure 6 The heat dissipation portion on the right side of the paper is called the right horizontal heat dissipation portion 46, which is arranged relative to the vertical heat dissipation portion 45. Figure 6 The heat dissipation portion on the left side of the paper is referred to as the left horizontal heat dissipation portion 47. Figure 6 In FIG. 1 , a portion located below the semiconductor element 10 among the boundaries of the three heat dissipating portions 45 to 47 is indicated by a dashed line.

[0077] The longitudinal heat dissipation portion 45 has high thermal conductivity in the in-plane direction of the YZ plane. The right transverse heat dissipation portion 46 and the left transverse heat dissipation portion 47 have high thermal conductivity in the in-plane direction of the XZ plane. In addition, the semiconductor element 10 is arranged so that at least a portion of the semiconductor element 10 overlaps the longitudinal heat dissipation portion 45, the right transverse heat dissipation portion 46, and the left transverse heat dissipation portion 47 in the thickness direction of the heat dissipation plate 20.

[0078] exist Figure 6 In FIG. 1 , a part of the path of heat generated from the semiconductor element 10 and transferred to the heat sink 20 is schematically indicated by arrows.

[0079] like Figure 6 As shown by arrow T6, the heat generated from the semiconductor element 10 is transferred in the Y direction within the width of the semiconductor element 10 in the longitudinal heat dissipation portion 45. Figure 6 As shown by arrow T7, the heat generated from the semiconductor element 10 is transferred in the right horizontal heat dissipation portion 46 and the left horizontal heat dissipation portion 47 along the X direction within the width of the semiconductor element 10. Figure 6 As shown by the middle hatched line LT, a region where heat is hardly transferred is formed outside the region where heat is transferred in the X and Y directions within the width of the semiconductor element 10. Therefore, the semiconductor module 102 of the second comparative example cannot effectively utilize the entire region of the heat sink 20 either.

[0080] Compared with the first comparative example and the second comparative example described above, the semiconductor module 1 of the first embodiment has the following effects. In the first embodiment, the heat sink 20 provided in the semiconductor module 1 includes a first heat sink 21 and a second heat sink 22 formed of a material having anisotropy in thermal conductivity. The first heat sink 21 is provided at a position opposite to the semiconductor element 10 in the thickness direction of the heat sink 20, and has high thermal conductivity in the in-plane direction of any first virtual plane parallel to the thickness direction of the heat sink 20. The second heat sink 22 is connected to the first heat sink 21 in a direction parallel to the in-plane direction of the first virtual plane and perpendicular to the thickness direction of the heat sink 20, and has high thermal conductivity in the in-plane direction of the second virtual plane perpendicular to the thickness direction of the heat sink 20.

[0081] Accordingly, the heat transferred from the semiconductor element 10 to the first heat dissipation portion 21 is diffused in the in-plane direction of the first virtual plane at a position directly below the semiconductor element 10 in the first heat dissipation portion 21. Therefore, part of the heat transferred from the semiconductor element 10 to the first heat dissipation portion 21 is dissipated from the cooling surface of the first heat dissipation portion 21, and the remaining part is transferred to the second heat dissipation portion 22. Figure 2 As shown by arrow T1, the heat transferred to the second heat dissipating portion 22 is diffused in the second heat dissipating portion 22 along the in-plane direction of the second virtual plane perpendicular to the thickness direction of the heat dissipating plate 20. Figure 2 As shown by the arrow T3, the heat is transferred from the second heat dissipation portion 22 to a portion of the first heat dissipation portion 21 extending in the Y direction relative to a position directly below the semiconductor element 10. The heat transferred from the second heat dissipation portion 22 to the first heat dissipation portion 21 is diffused in the first heat dissipation portion 21 along the in-plane direction of the first virtual plane, and is dissipated from the cooling surface of the first heat dissipation portion 21. In this way, in the first embodiment, by providing the second heat dissipation portion 22 functioning as a heat direction conversion portion outside the first heat dissipation portion 21, the heat generated by the semiconductor element 10 can be diffused to a larger range of the heat dissipation plate 20, and can be dissipated from the cooling surface of the heat dissipation plate 20. Therefore, the semiconductor module 1 can expand the area where the heat dissipation plate 20 functions as a heat dissipation surface, and improve the heat dissipation performance of the heat dissipation plate 20.

[0082] In the first embodiment, the second heat dissipation portion 22 is connected to a portion of the first heat dissipation portion 21 that is parallel to the in-plane direction of the first virtual plane and perpendicular to the thickness direction of the heat sink 20 relative to the position directly below the semiconductor element 10. Furthermore, the second heat dissipation portion 22 is also connected to a portion of the first heat dissipation portion 21 that extends in a direction perpendicular to the in-plane direction of the first virtual plane relative to the position directly below the semiconductor element 10. Figure 2 As shown by arrow T1, the heat transferred from the semiconductor element 10 to the first heat dissipation portion 21 can be transferred to the second heat dissipation portion 22 and diffused in the second heat dissipation portion 22. Figure 2As shown by arrow T3 , the heat diffused into the second heat dissipating portion 22 can be transferred from the second heat dissipating portion 22 to a portion of the first heat dissipating portion 21 extending in the Y direction relative to a position directly below the semiconductor element 10 .

[0083] In the first embodiment, the heat sink 20 further includes a third heat sink 23. The third heat sink 23 is connected to the second heat sink 22 in an arbitrary direction parallel to the in-plane direction of the second virtual plane. Furthermore, the third heat sink 23 has high thermal conductivity in the in-plane direction of the third virtual plane which is not perpendicular to the direction in which the third heat sink 23 is connected to the second heat sink 22 and is parallel to the thickness direction of the heat sink 20. Figure 2 As shown by the arrow T2, the heat diffused from the semiconductor element 10 to the second heat dissipating portion 22 via the first heat dissipating portion 21 is transferred to the third heat dissipating portion 23. The heat is diffused in the third heat dissipating portion 23 along the in-plane direction of the third virtual plane parallel to the thickness direction of the heat dissipating plate 20, and is dissipated from the cooling surface of the third heat dissipating portion 23. In this way, in the first embodiment, by providing the third heat dissipating portion 23 on the side opposite to the first heat dissipating portion 21 with respect to the second heat dissipating portion 22, the amount of heat transferred from the heat dissipating plate 20 to the cooler 30 can be increased. Therefore, the semiconductor module 1 can increase the area where the heat dissipating plate 20 functions as a heat dissipating surface, and improve the heat dissipation of the heat dissipating plate 20.

[0084] In the first embodiment, the third virtual plane defining the direction in which the third heat dissipation portion 23 has high thermal conductivity is parallel to the direction in which the third heat dissipation portion 23 is connected to the second heat dissipation portion 22 and is parallel to the thickness direction. Accordingly, when the heat dissipation plate 20 is rectangular, for example, it is possible to suppress the formation of a portion in the third heat dissipation portion 23 where heat is difficult to transfer, and the heat transferred from the semiconductor element 10 to the first heat dissipation portion 21 can be transferred to the entire third heat dissipation portion 23 via the second heat dissipation portion 22. Therefore, the heat dissipation performance of the heat dissipation plate 20 can be improved.

[0085] In the first embodiment, the first virtual plane defining the direction in which the first heat dissipation part 21 has high thermal conductivity and the third virtual plane defining the direction in which the third heat dissipation part 23 has high thermal conductivity are parallel to the direction in which the first heat dissipation part 21, the second heat dissipation part 22, and the third heat dissipation part 23 are arranged. According to this, the orientation of the virtual plane defining the direction in which the first heat dissipation part 21 and the third heat dissipation part 23 have high thermal conductivity, specifically, the orientation of the layers of the plurality of graphenes 3 constituting the graphite 2, is made the same, so that the configuration of the heat dissipation plate 20 can be simplified and the manufacturing process can be simplified. In addition, when the heat dissipation plate 20 is rectangular, for example, it is possible to suppress the formation of a portion in the third heat dissipation part 23 where heat is difficult to transfer, and the heat transferred from the semiconductor element 10 to the first heat dissipation part 21 is transferred to the entire third heat dissipation part 23 via the second heat dissipation part 22. Therefore, the heat dissipation of the heat dissipation plate 20 can be improved.

[0086] (Second embodiment)

[0087] The second embodiment is described. The second embodiment changes a part of the structure of the heat sink 20 relative to the first embodiment, and is the same as the first embodiment in other respects, so only the parts different from the first embodiment are described. In addition, in the figures referred to in the description of the second embodiment and thereafter, the illustration of the cooler 30 and the like is omitted.

[0088] like Figure 7 as well as Figure 8 As shown in the figure, in the second embodiment, the heat sink 20 has the first heat sink 21 to the fifth heat sink 25. In the description of the second embodiment and the drawings referred to in the description, in addition to the numerals 22 to 25 representing the second heat sink 21 to the fifth heat sink 25, the letter symbols R and L indicating the position of each heat sink are added at the end. This is also the same in the description of the third embodiment described later and the drawings referred to in the description.

[0089] The first heat dissipation portion 21, the second heat dissipation portion 22, and the third heat dissipation portion 23 are the same as those described in the first embodiment. The fourth heat dissipation portion 24 is a portion connected to the third heat dissipation portion 23 in a direction parallel to the in-plane direction of the third virtual plane and perpendicular to the thickness direction of the heat dissipation plate 20. Specifically, the fourth heat dissipation portion 24 is a portion connected to the third heat dissipation portion 23 in the X direction. In the second embodiment, the heat dissipation plate 20 has two fourth heat dissipation portions 24. Of the two fourth heat dissipation portions 24, the one disposed on the X direction relative to the one side third heat dissipation portion 23R is referred to as the one side fourth heat dissipation portion 24R, and the one disposed on the other side of the X direction relative to the other side third heat dissipation portion 23L is referred to as the other side fourth heat dissipation portion 24L.

[0090] The fourth heat dissipation portion 24 has high thermal conductivity in the in-plane direction of the fourth virtual plane, that is, the XY plane, which is perpendicular to the thickness direction of the heat dissipation plate 20, similarly to the second heat dissipation portion 22. Therefore, the fourth heat dissipation portion 24 functions as a heat direction converter similarly to the second heat dissipation portion 22.

[0091] The fifth heat sink 25 is a portion connected to the fourth heat sink 24 in an arbitrary direction parallel to the in-plane direction of the fourth virtual plane, that is, the XY plane. In the second embodiment, the first heat sink 21 to the fifth heat sink 25 are all arranged in the X direction. The fifth heat sink 25 is a portion connected to the fourth heat sink 24 in the X direction. In the second embodiment, the heat sink 20 has two fifth heat sinks 25. Of the two fifth heat sinks 25, the one disposed on the X direction relative to the fourth heat sink 24R on one side is referred to as the fifth heat sink 25R on one side, and the one disposed on the other side in the X direction relative to the fourth heat sink 24L on the other side is referred to as the fifth heat sink 25L on the other side.

[0092] Here, a surface that is not perpendicular to the direction in which the fifth heat dissipation portion 25 is connected to the fourth heat dissipation portion 24 and is parallel to the thickness direction of the heat dissipation plate 20 is referred to as a fifth virtual surface. The fifth heat dissipation portion 25 has high thermal conductivity in the in-plane direction of the fifth virtual surface. In the second embodiment, the fifth virtual surface is a surface that is parallel to the direction in which the fifth heat dissipation portion 25 is connected to the fourth heat dissipation portion 24 and is parallel to the thickness direction of the heat dissipation plate 20. Therefore, the fifth virtual surface is the same as the first virtual surface and the third virtual surface, and is an XZ surface. Therefore, the fifth heat dissipation portion 25 has high thermal conductivity in the in-plane direction of the XZ surface.

[0093] exist Figure 8 In FIG. 1 , a part of the path along which the heat generated from the semiconductor element 10 is transferred in the heat sink 20 is schematically indicated by arrows.

[0094] Figure 8 The heat transfer paths indicated by arrows T1 to T3 are the same as those described in the first embodiment.

[0095] As indicated by arrow T8, the heat transferred from the third heat sink 23 to the fourth heat sink 24 is diffused along the XY plane in the fourth heat sink 24. As indicated by arrow T9, a portion of the heat diffused along the XY plane in the fourth heat sink 24 is transferred to the fifth heat sink 25 located in the X direction, diffused along the XZ plane in the fifth heat sink 25, and dissipated from the cooling surface of the fifth heat sink 25. In addition, as indicated by arrow T10, another portion of the heat diffused along the XY plane in the fourth heat sink 24 is transferred to the third heat sink 23 located in the X direction, and dissipated from the cooling surface of the third heat sink 23.

[0096] Thus, in the second embodiment, by using the second heat dissipation portion 22 and the fourth heat dissipation portion 24 as heat direction conversion portions, the heat generated by the semiconductor element 10 can be diffused to substantially the entire area of ​​the heat dissipation plate 20 and dissipated from the cooling surface of the heat dissipation plate 20. Therefore, the semiconductor module 1 can increase the area in which the heat dissipation plate 20 functions as a heat dissipation surface, thereby improving the heat dissipation performance of the heat dissipation plate 20.

[0097] (Third embodiment)

[0098] The third embodiment is also different from the first embodiment in that a part of the configuration of the heat sink 20 is changed, and the other parts are the same as the first embodiment, so only the parts different from the first embodiment will be described.

[0099] like Fig. 9 as well as Fig.10As shown, in the third embodiment, the heat sink 20 includes the first heat sink 21 to the fourth heat sink 24. The first heat sink 21 to the fourth heat sink 24 are the same as those described in the second embodiment.

[0100] exist Fig.10 In FIG. 1 , a part of the path along which the heat generated from the semiconductor element 10 is transferred in the heat sink 20 is schematically indicated by arrows.

[0101] Fig.10 The heat transfer paths indicated by arrows T1 to T3 are the same as those described in the first embodiment. As indicated by arrow T11, the heat transferred from the third heat dissipating portion 23 to the fourth heat dissipating portion 24 is diffused along the XY plane in the fourth heat dissipating portion 24. As indicated by arrow T12, the heat diffused along the XY plane in the fourth heat dissipating portion 24 is transferred to the third heat dissipating portion 23 located in the X direction. Then, the heat is diffused along the XZ plane in the third heat dissipating portion 23 and is dissipated from the cooling surface of the third heat dissipating portion 23.

[0102] Thus, in the third embodiment, the second heat dissipation portion 22 and the fourth heat dissipation portion 24 are used as heat direction conversion portions, so that the heat generated by the semiconductor element 10 can be diffused to substantially the entire area of ​​the heat dissipation plate 20 and dissipated from the cooling surface of the heat dissipation plate 20. Therefore, the semiconductor module 1 can increase the area in which the heat dissipation plate 20 functions as a heat dissipation surface, thereby improving the heat dissipation performance of the heat dissipation plate 20.

[0103] (Fourth to Eighth Embodiments)

[0104] The fourth to eighth embodiments are different from the first embodiment in that the shape of the heat sink 20 is changed, and the other parts are the same as the first embodiment, so only the parts different from the first embodiment will be described.

[0105] (Fourth embodiment)

[0106] like Fig.11 As shown in the fourth embodiment, the heat sink 20 is circular in plan view from the thickness direction. The outer edges of the first heat sink 21, the second heat sink 22, and the third heat sink 23 are all arc-shaped. Fig.11 The area of ​​the second heat dissipation portion 22R on the right side of the paper is equal to the area of ​​the first heat dissipation portion 21. Fig.11 The area of ​​the second heat dissipation portion 22L on the left side of the paper is the same. Fig.11 The area of ​​the third heat dissipation portion 23R on the right side of the paper is equal to that of the first heat dissipation portion 21. Fig.11 The area of ​​the third heat dissipating portion 23L on the left side of the paper is the same.

[0107] (Fifth embodiment)

[0108] like Fig.12 As shown in the fifth embodiment, the heat sink 20 has a triangular shape when viewed from the thickness direction. Two of the three vertices of the triangle are formed at the positions arranged at Fig.12 The third heat dissipation portion 23R on the right side of the paper has another vertex formed at the Fig.12 The third heat dissipation portion 23L on the left side of the paper.

[0109] In addition, the first heat dissipation portion 21 is arranged at Fig.12 The area ratio of the second heat dissipation portion 22R on the right side of the paper is 2.3 times that of the first heat dissipation portion 21. Fig.12 The second heat dissipation portion 22L on the left side of the paper has a larger area. Fig.12 The area ratio of the third heat dissipation portion 23R on the right side of the paper is 2.3 times that of the first heat dissipation portion 21. Fig.12 The third heat dissipation portion 23L on the left side of the paper has a larger area.

[0110] (Sixth embodiment)

[0111] like Fig.13 As shown in FIG. 1 , in the sixth embodiment, the heat sink 20 is also triangular in plan view from the thickness direction. The three vertices of the triangle are located in the first heat sink 21. Fig.13 The upper part of the paper, placed in Fig.13 The third heat dissipation portion 23R on the right side of the paper and the Fig.13 One each is formed on the third heat dissipating portion 23L on the left side of the paper.

[0112] In addition, the first heat dissipation portion 21 is arranged at Fig.13 The area of ​​the second heat dissipation portion 22R on the right side of the paper is equal to the area of ​​the first heat dissipation portion 21. Fig.13 The area of ​​the second heat dissipation portion 22L on the left side of the paper is the same. Fig.13 The area of ​​the third heat dissipation portion 23R on the right side of the paper is equal to that of the first heat dissipation portion 21. Fig.13 The area of ​​the third heat dissipating portion 23L on the left side of the paper is the same.

[0113] (Seventh Implementation Method)

[0114] like Fig.14 As shown, in the seventh embodiment, the heat sink 20 is rectangular when viewed from the thickness direction. Specifically, the heat sink 20 is a rectangle whose side length in the X direction is longer than the side length in the Y direction. Although not shown in the figure, the heat sink 20 may also be a rectangle whose side length in the X direction is shorter than the side length in the Y direction.

[0115] (Eighth Implementation Method)

[0116] like Fig.15 As shown in FIG. 1 , in the eighth embodiment, the heat sink 20 is hexagonal in plan view from the thickness direction thereof. Specifically, the first heat sink 21 is disposed at Fig.15 The center portion of the third heat dissipation portion 23R on the right side of the paper in the Y direction protrudes to the right side in the X direction. Fig.15 The center portion of the third heat dissipation portion 23L on the left side of the paper in the Y direction protrudes to the left in the X direction. Three of the six vertices of the hexagon are formed in the Fig.15 The third heat dissipation portion 23R on the right side of the paper has three other vertices formed at Fig.15 The third heat dissipation portion 23L on the left side of the paper.

[0117] The shape of the heat sink 20 is not limited to the shapes exemplified in the first to eighth embodiments, and various shapes such as an elliptical shape or a polygonal shape may be adopted.

[0118] (9th to 12th embodiments)

[0119] The ninth to twelfth embodiments are similar to the first embodiment except that the shape and mounting position of the semiconductor element 10 are changed compared to the first embodiment. Therefore, only the parts different from the first embodiment will be described.

[0120] (Ninth Implementation Method)

[0121] like Fig.16 As shown, in the ninth embodiment, at least a portion of the semiconductor element 10 is overlapped with both the first heat dissipation portion 21 and the second heat dissipation portion 22 in the thickness direction of the heat dissipation plate 20. That is, the semiconductor element 10 may be partially overlapped not only with the first heat dissipation portion 21 but also with the second heat dissipation portion 22.

[0122] (10th embodiment)

[0123] like Fig.17 As shown, in the tenth embodiment, a plurality of semiconductor elements 10 are provided for the heat sink 20. Specifically, two semiconductor elements 10 are both provided on the first heat sink 21. In this way, a plurality of semiconductor elements 10 can be mounted on the heat sink 20. In addition, the number of semiconductor elements 10 is not limited to two, but can be set arbitrarily, and the mounting positions thereof can also be set arbitrarily.

[0124] (11th embodiment)

[0125] like Fig.18As shown, in the eleventh embodiment, a rectangular semiconductor element 10 is mounted. As described above, the shape of the semiconductor element 10 can be any shape. In addition, the aspect ratio of the shape of the semiconductor element 10 can also be set arbitrarily.

[0126] (12th embodiment)

[0127] like Fig.19 As shown, in the twelfth embodiment, the semiconductor element 10 is provided in the heat sink 20. Fig.19 The semiconductor element 10 may be provided in any heat dissipation portion having high thermal conductivity in the in-plane direction of any virtual plane parallel to the thickness direction of the heat dissipation plate 20 among the plurality of heat dissipation portions constituting the heat dissipation plate 20 .

[0128] In the present disclosure, as described in the first embodiment, among the plurality of heat dissipation portions constituting the heat dissipation plate 20, a heat dissipation portion which is provided at a position opposed to the semiconductor element 10 in the thickness direction of the heat dissipation plate 20 and has high thermal conductivity in the in-plane direction of an arbitrary first virtual plane parallel to the thickness direction of the heat dissipation plate 20 is referred to as a first heat dissipation portion 21. Fig.19 The heat dissipation portion on the left side of the paper is called the first heat dissipation portion 21, and the heat dissipation portion 21 is directed toward the first heat dissipation portion 21. Fig.19 The heat dissipating parts arranged on the right side of the paper are referred to as second heat dissipating parts 22 to fifth heat dissipating parts 25. The second heat dissipating parts 22 and the fourth heat dissipating parts 24 function as heat direction converting parts.

[0129] (13th and 14th embodiments)

[0130] The thirteenth and fourteenth embodiments are similar to the first embodiment in that a plurality of heat dissipating portions constituting the heat dissipation plate 20 are arranged radially around the semiconductor element 10 . Therefore, only the differences from the first embodiment will be described.

[0131] (13th embodiment)

[0132] like Fig. 20 As shown, in the 13th embodiment, the heat sink 20 provided in the semiconductor module 1 is provided with a first heat sink 21, a second heat sink 22, and a third heat sink 23 radially arranged around the semiconductor element 10. In other words, the second heat sink 22 is provided in a ring shape outside the first heat sink 21, and the third heat sink 23 is provided in a ring shape outside the second heat sink 22. The heat sink 20 is a quadrilateral. The first heat sink 21, the second heat sink 22, and the third heat sink 23 are each divided into four parts by the diagonal line of the quadrilateral.

[0133] In addition, in the description of the 13th embodiment and the references therein, Fig. 20 In FIG. 1 , in addition to the numerical symbols 22 to 23 indicating the first heat dissipation section 21 to the third heat dissipation section 23, the letter symbols a to d indicating the parts of the respective heat dissipation sections are added at the end thereof. Fig. 20 In FIG. 1 , the boundary lines of the first heat dissipation part 21, the second heat dissipation part 22, and the third heat dissipation part 23 and the boundary lines of each part are shown by solid lines, but in fact, they are formed integrally. Fig. 20 In FIG. 14 , the portion located below the semiconductor element 10 among the boundaries of the various parts of the first heat dissipation portion 21 is indicated by a single-dot chain line. These details will be described in the description of the 14th embodiment described later and in the description referred to in the description. Fig.21 The same is true in Chinese.

[0134] Each portion of the first heat dissipation portion 21 has high thermal conductivity in the in-plane direction of the first virtual plane, which is an arbitrary plane parallel to the thickness direction of the heat dissipation plate 20. Specifically, among the four portions of the first heat dissipation portion 21, Fig. 20 The upper portion 21a on the paper is arranged Fig. 20 The portion 21b on the lower side of the paper has high thermal conductivity in the in-plane direction of the YZ plane, which is the first virtual plane. Fig. 20 The portion 21c on the right side of the paper is configured Fig. 20 The portion 21d on the left side of the paper has high thermal conductivity in the in-plane direction of the XZ plane, which is the first virtual plane.

[0135] Each part of the second heat dissipation part 22 is a portion connected to each part of the first heat dissipation part 21 in a direction parallel to the in-plane direction of the first virtual plane and perpendicular to the thickness direction. Each part of the second heat dissipation part 22 has high thermal conductivity in the in-plane direction of the second virtual plane perpendicular to the thickness direction of the heat sink 20. Specifically, the four parts 22a, 22b, 22c, and 22d of the second heat dissipation part 22 all have high thermal conductivity in the in-plane direction of the XY plane as the second virtual plane.

[0136] Each portion of the third heat dissipation portion 23 is a portion connected to each portion of the second heat dissipation portion 22 in an arbitrary direction parallel to the in-plane direction of the second virtual plane. Each portion of the third heat dissipation portion 23 has high thermal conductivity in the in-plane direction of the third virtual plane which is not perpendicular to the direction in which the third heat dissipation portion 23 is connected to the second heat dissipation portion 22 and is parallel to the thickness direction of the heat sink 20. Specifically, among the four portions of the third heat dissipation portion 23, the portion disposed at Fig. 20 The upper portion 23a on the paper is arranged Fig. 20 The portion 23b on the lower side of the paper has high thermal conductivity in the in-plane direction of the YZ plane, which is the third virtual plane. Fig. 20The portion 23c on the right side of the paper is configured Fig. 20 The portion 24d on the left side of the paper has high thermal conductivity in the in-plane direction of the XZ plane, which is the third virtual plane.

[0137] In the thirteenth embodiment described above, the second heat sink 22 that functions as a heat direction converter is provided between the first heat sink 21 and the third heat sink 23, so that the heat generated by the semiconductor element 10 can be diffused to substantially the entire area of ​​the heat sink 20. Therefore, the semiconductor module 1 can increase the area where the heat sink 20 functions as a heat dissipation surface, thereby improving the heat dissipation performance of the heat sink 20.

[0138] (14th embodiment)

[0139] like Fig.21 As shown, in the 14th embodiment, the heat sink 20 also provided in the semiconductor module 1 is provided with a first heat sink 21, a second heat sink 22 and a third heat sink 23 in a radial pattern with the semiconductor element 10 as the center. In other words, the second heat sink 22 is provided in a ring shape outside the first heat sink 21, and the third heat sink 23 is provided in a ring shape outside the second heat sink 22. The heat sink 20 is hexagonal. The first heat sink 21, the second heat sink 22 and the third heat sink 23 are each divided into six parts using the diagonal lines of the hexagon. In addition, Fig.21 In FIG. 1 , in addition to the numerals 22 to 23 indicating the first to third heat dissipating portions 21 to 23 , alphabetical symbols e to j indicating the parts of the respective heat dissipating portions are added at the end thereof.

[0140] In addition, Fig.21 In the 3D coordinates based on the X-axis, Y-axis, and Z-axis, the P-axis and Q-axis are added. The P-axis is an axis rotated 30° counterclockwise relative to the X-axis in the XY plane, and the Q-axis is an axis rotated 30° clockwise relative to the X-axis in the XY plane.

[0141] Each portion of the first heat dissipation portion 21 has high thermal conductivity in the in-plane direction of the first virtual plane, which is an arbitrary plane parallel to the thickness direction of the heat dissipation plate 20. Specifically, among the six portions of the first heat dissipation portion 21, Fig.21 The upper portion 21e of the paper is configured Fig.21 The portion 21f on the lower side of the paper has high thermal conductivity in the in-plane direction of the YZ plane, which is the first virtual plane. Fig.21 The portion 21g on the upper right side of the paper and the Fig.21 The portion 21h on the lower left side of the paper has high thermal conductivity in the in-plane direction of the PZ plane, which is the first virtual plane. Fig.21 The portion 21i on the lower right side of the paper and the Fig.21The portion 21j on the upper left side of the paper has high thermal conductivity in the in-plane direction of the QZ plane which is the first virtual plane.

[0142] Each part of the second heat dissipation part 22 is a portion connected to each part of the first heat dissipation part 21 in a direction parallel to the in-plane direction of the first virtual plane and perpendicular to the thickness direction. Each part of the second heat dissipation part 22 has high thermal conductivity in the in-plane direction of the second virtual plane perpendicular to the thickness direction of the heat sink 20. Specifically, the six parts 22e, 21f, 21g, 21h, 21i, and 21j of the second heat dissipation part 22 all have high thermal conductivity in the in-plane direction of the XY plane as the second virtual plane.

[0143] The third heat dissipation portion 23 is a portion connected to the second heat dissipation portion 22 in an arbitrary direction parallel to the in-plane direction of the second virtual plane. The third heat dissipation portion 23 has high thermal conductivity in the in-plane direction of the third virtual plane which is not perpendicular to the direction in which the third heat dissipation portion 23 is connected to the second heat dissipation portion 22 and is parallel to the thickness direction of the heat sink 20. Specifically, among the six portions of the third heat dissipation portion 23, the third heat dissipation portion 23 is arranged at Fig.21 The upper portion 23e of the paper is configured Fig.21 The portion 23f on the lower side of the paper has high thermal conductivity in the in-plane direction of the YZ plane which is the third virtual plane. Fig.21 The portion 23g on the upper right side of the paper and the Fig.21 The portion 23h on the lower left side of the paper has high thermal conductivity in the in-plane direction of the PZ plane which is the third virtual plane. Fig.21 The portion 23i on the lower right side of the paper and the Fig.21 The portion 23j on the upper left side of the paper has high thermal conductivity in the in-plane direction of the QZ plane which is the third virtual plane.

[0144] In the 14th embodiment described above, the second heat sink 22 that functions as a heat direction converter is provided between the first heat sink 21 and the third heat sink 23, so that the heat generated by the semiconductor element 10 can be diffused to substantially the entire area of ​​the heat sink 20. Therefore, the semiconductor module 1 can increase the area where the heat sink 20 functions as a heat dissipation surface, thereby improving the heat dissipation performance of the heat sink 20.

[0145] (15th embodiment)

[0146] The fifteenth embodiment is described below. The fifteenth embodiment changes a part of the configuration of the heat sink 20 from the first embodiment, and is the same as the first embodiment in other respects, so only the parts different from the first embodiment will be described below.

[0147] like Fig. 22As shown, in the fifteenth embodiment, the heat sink 20 has metal plates 50 on the surface on one side and the surface on the other side facing the thickness direction with respect to the first heat sink 21, the second heat sink 22, and the third heat sink 23. In other words, the heat sink 20 has metal plates 50 on the element mounting side and the cooling surface. In addition, the metal plates 50 are formed of a material with a low resistivity, such as copper.

[0148] The semiconductor element 10 is bonded to the metal plate 50 provided on the element mounting side surface of the heat sink 20 by the bonding material 11. The bonding material 11 is solder, for example.

[0149] The semiconductor module 1 of the fifteenth embodiment described above provides the metal plate 50 on the device mounting side of the heat sink 20 , and the metal plate 50 can be used as wiring for energizing the semiconductor device 10 , thereby improving the functionality of the semiconductor module 1 .

[0150] In addition, by providing the metal plates 50 on the element mounting side and the cooling surface of the heat sink 20, respectively, heat can be further diffused in the first heat sink 21 and the third heat sink 23 via the metal plates 50 in the direction perpendicular to the thickness direction of the heat sink 20, that is, in the in-plane direction of the XY plane. Therefore, heat can be diffused to substantially the entire area of ​​the heat sink 20, and the heat dissipation performance of the heat sink 20 can be improved.

[0151] Here, the results of analyzing the temperature distribution when the semiconductor element 10 generates heat in the semiconductor module 1 described in the fifteenth embodiment and the semiconductor module of the third comparative example will be described.

[0152] First, the structure of the semiconductor module of the third comparative example as a comparison object is described. Fig.25 As shown, the semiconductor module 103 of the third comparative example also includes a semiconductor element 10 and a heat sink 20. The semiconductor element 10 is the same as that of the fifteenth embodiment. The heat sink 20 has a heat sink 48 formed of graphite 2 and a metal plate 50 provided on the element mounting side and the cooling surface with respect to the heat sink 48. The heat sink 48 of the heat sink 20 has high thermal conductivity in the in-plane direction of the XZ plane. The metal plate 50 is formed of copper as in the fifteenth embodiment.

[0153] The semiconductor module 1 described in the fifteenth embodiment and the semiconductor module 103 of the third comparative example were subjected to a steady-state thermal analysis. The steady-state thermal analysis was conducted under the condition that the heat generation of the semiconductor element 10 was constant and cooling water at a water temperature of 30°C flowed through the cooler 30 provided on the cooling surface side of the heat sink 20. The size of the heat sink 20 was set to 40 mm in the X direction and 20 mm in the Y direction. The size of the semiconductor element 10 was set to 6.5 mm in both the X direction and the Y direction. In the semiconductor module 1 of the fifteenth embodiment, the size of the first heat sink 21 in the X direction was set to 6.5 mm, and the size of each of the second heat sinks 22R and 22L in the X direction was set to 5 mm.

[0154] The results of analyzing the semiconductor module 1 of the fifteenth embodiment are shown in FIG. Fig.23 and Fig.24 The results of analyzing the semiconductor module 103 of the third comparative example are shown in FIG. Fig.26 and Fig. 27 middle.

[0155] As a result of the analysis, the temperature of the heat sink 20 provided in the semiconductor module 1 of the fifteenth embodiment is substantially uniform over the entire area of ​​the heat sink 20, compared with the temperature of the heat sink 20 provided in the semiconductor module 103 of the third comparative example. Therefore, it can be said that the heat sink 20 provided in the semiconductor module 1 of the fifteenth embodiment can dissipate heat using the entire area of ​​the heat sink 20, compared with the heat sink 20 provided in the semiconductor module 103 of the third comparative example.

[0156] In contrast, the heat sink 20 of the semiconductor module 103 of the third comparative example has lower temperatures at one side of the Y direction than at the other side of the heat sink 20 of the semiconductor module 1 of the fifteenth embodiment. Therefore, the heat sink 20 of the semiconductor module 103 of the third comparative example has a portion where heat is difficult to transfer, that is, a useless portion, compared to the heat sink 20 of the semiconductor module 1 of the fifteenth embodiment.

[0157] Regarding the temperature of the semiconductor element 10, the maximum temperature of the semiconductor element 10 provided in the semiconductor module 103 of the third comparative example is 150° C., whereas the maximum temperature of the semiconductor element 10 provided in the semiconductor module 1 of the fifteenth embodiment is 127° C. Therefore, it can be seen that the semiconductor module 1 of the fifteenth embodiment can reduce the temperature of the semiconductor element 10 by using the entire area of ​​the heat sink 20 to dissipate heat compared to the semiconductor module 103 of the third comparative example.

[0158] (16th Implementation Method)

[0159] The 16th embodiment is described. The 16th embodiment is a modified example of the 15th embodiment. In the 15th embodiment, a metal plate 50 is provided on the element mounting side and the cooling surface of the heat sink 20. In contrast, in the 16th embodiment, Fig.28 As shown, an insulator 51 is provided on the element mounting side and the cooling surface of the heat sink 20. The insulator 51 is, for example, ceramic. In addition, the ceramic preferably has a high thermal conductivity.

[0160] In addition, in the first heat dissipation portion 21 and the third heat dissipation portion 23, heat is further diffused in a direction perpendicular to the thickness direction of the heat dissipation plate 20, that is, in the in-plane direction of the XY plane, via the insulator 51, thereby improving the heat dissipation performance of the heat dissipation plate 20.

[0161] In addition, as another modification of the fifteenth and sixteenth embodiments, although not shown in the figure, a metal plate 50 may be provided on the element mounting side of the heat sink 20, and an insulator 51 may be provided on the cooling surface. Thus, the metal plate 50 provided on the element mounting side of the heat sink 20 can be used as wiring, and the insulator 51 provided on the cooling surface side of the heat sink 20 can be used to electrically insulate the semiconductor module 1 from the outside.

[0162] In addition, the metal plate 50 and the insulator 51 are not limited to being provided on the entire surface of the heat sink 20 in the thickness direction, and may be provided on a part thereof.

[0163] (17th Implementation Method)

[0164] The seventeenth embodiment will be described. The seventeenth embodiment changes a part of the configuration of the heat sink 20 compared to the fifteenth and sixteenth embodiments.

[0165] like Fig.29 As shown, in the 17th embodiment, the heat sink 20 has a plate-shaped insulator 52 at the middle position in the thickness direction. The insulator 52 is, for example, ceramic. In addition, the ceramic preferably has a high thermal conductivity. In addition, the heat sink 20 has a metal plate 50 on the element mounting side and the cooling surface, respectively, as in the 15th embodiment. The metal plate 50 is formed of a material with a low resistivity, such as copper.

[0166] The semiconductor module 1 of the 17th embodiment described above has a plate-shaped insulator 52 at a middle position in the thickness direction of the heat sink 20, so that the semiconductor module 1 can be electrically insulated from the outside. In addition, the metal plate 50 provided on the element mounting side of the heat sink 20 can be used as wiring. Moreover, in the first heat sink 21 and the third heat sink 23, heat is further diffused in a direction perpendicular to the thickness direction of the heat sink 20, that is, in the in-plane direction of the XY plane, through the metal plate 50 and the insulator 52, thereby improving the heat dissipation of the heat sink 20.

[0167] As a modification of the seventeenth embodiment, a metal plate 50 may be provided in place of the insulator 52 or in combination with the insulator 52 at a middle position in the thickness direction of the heat sink 20 .

[0168] As another modified example of the seventeenth embodiment, an insulator 51 may be provided on at least one of the element mounting side surface and the cooling surface of the heat sink 20 instead of the metal plate 50 .

[0169] (Eighteenth Implementation Method)

[0170] The eighteenth embodiment will be described. In the eighteenth embodiment, a part of the configuration of the heat sink 20 is changed compared to the first embodiment.

[0171] like Fig.30 as well as Fig.31 As shown, in the 18th embodiment, the heat sink 20 has a metal plate 50 that covers the surface facing the thickness direction and the surface facing the direction perpendicular to the thickness direction. In other words, the plurality of heat dissipating parts constituting the heat sink 20 are covered in a capsule shape by the metal plate 50. In addition, the metal plate 50 is formed of a material with a low resistivity, such as copper.

[0172] The semiconductor element 10 is bonded to the metal plate 50 provided on the element mounting side surface of the heat sink 20 by the bonding material 11. The bonding material 11 is solder, for example.

[0173] The semiconductor module 1 of the eighteenth embodiment described above can achieve the same effects as the semiconductor module 1 of the fifteenth embodiment. In addition, the semiconductor module 1 of the eighteenth embodiment can improve the rigidity of the heat sink 20 by using the metal plate 50 covering the plurality of heat dissipating portions in a capsule shape.

[0174] In addition, as a modification of the eighteenth embodiment, the metal plate 50 covering the heat sink 20 may partially cover a part of the heat sink 20 .

[0175] (19th Implementation Method)

[0176] The nineteenth embodiment will be described. The nineteenth embodiment is different from the first embodiment in that a part of the configuration of the heat sink 20 is changed.

[0177] like Fig.32 As shown, in the nineteenth embodiment, the heat sink 20 has a plating layer 53 covering the surface facing the thickness direction and the surface facing the direction perpendicular to the thickness direction. In other words, the plurality of heat sinks constituting the heat sink 20 are covered with the plating layer 53.

[0178] The semiconductor element 10 is bonded to the plating layer 53 provided on the element mounting side surface of the heat sink 20 by the bonding material 11. The bonding material 11 is solder, for example.

[0179] The semiconductor module 1 according to the nineteenth embodiment described above can achieve the same operational effects as those of the semiconductor module 1 according to the eighteenth embodiment.

[0180] In addition, as a modification of the nineteenth embodiment, the plating layer 53 covering the heat dissipation plate 20 may partially cover a part of the heat dissipation plate 20 .

[0181] (Implementation 20)

[0182] The twentieth embodiment is described below. The twentieth embodiment changes a part of the configuration of the heat sink 20 from the first embodiment, and is the same as the first embodiment in other respects, so only the parts different from the first embodiment will be described below.

[0183] like Fig.33 as well as Fig.34 As shown in FIG. 1 , in the 20th embodiment, the heat sink 20 has a first heat sink 21 and a second heat sink 22. The first heat sink 21 and the second heat sink 22 are the same as those described in the first embodiment. Fig.34 In the figure, in order to explain the boundary between the portion of the first heat dissipation portion 21 in the X direction relative to the position directly below the semiconductor element 10 and the portion of the first heat dissipation portion 21 extending in the direction perpendicular to the in-plane direction of the first virtual plane relative to the position directly below the semiconductor element 10, two-dot chain lines D1 to D4 are used. The second heat dissipation portion 22 is connected to the portion of the first heat dissipation portion 21 in the X direction relative to the position directly below the semiconductor element 10, and is also connected in the X direction to the portion of the first heat dissipation portion extending in the direction perpendicular to the in-plane direction of the first virtual plane relative to the position directly below the semiconductor element 10.

[0184] exist Fig.34 In FIG. 1 , a part of the path along which the heat generated from the semiconductor element 10 is transferred in the heat sink 20 is schematically indicated by arrows.

[0185] After the heat generated from the semiconductor element 10 is transferred to the position directly below the semiconductor element 10 in the first heat dissipation portion 21, as shown in FIG. Fig.34 As shown by arrow T13, the heat is transferred from this position to the second heat dissipation portion 22 located in the X direction. Then, the heat is diffused along the XY plane in the second heat dissipation portion 22. In addition, although arrows are omitted, a part of the heat transferred from the semiconductor element 10 to the position directly below the semiconductor element 10 in the first heat dissipation portion 21 is diffused along the XZ plane at the position directly below the semiconductor element 10 in the first heat dissipation portion 21, and is dissipated from the cooling surface of the first heat dissipation portion 21.

[0186] As indicated by arrow T14, the heat diffused along the XY plane in the second heat dissipating portion 22 is transferred to the portion of the first heat dissipating portion 21 extending in the Y direction relative to the position directly below the semiconductor element 10. Then, the heat diffuses along the XZ plane in the portion of the first heat dissipating portion 21 extending in the Y direction relative to the position directly below the semiconductor element 10, and is dissipated from the cooling surface of the first heat dissipating portion 21.

[0187] Thus, in the semiconductor module 1 of the twentieth embodiment, the second heat dissipation portion 22 is also used as a heat direction conversion portion, so that the heat generated by the semiconductor element 10 can be diffused to substantially the entire area of ​​the heat sink 20 and dissipated from the cooling surface of the heat sink 20. Therefore, the semiconductor module 1 can increase the area in which the heat sink 20 functions as a heat dissipation surface, thereby improving the heat dissipation performance of the heat sink 20.

[0188] In the 20th embodiment, the second heat dissipation parts 22R and 22L are respectively arranged on one side and the other side in the X direction with respect to the first heat dissipation part 21. In contrast, as a modification of the 20th embodiment, the second heat dissipation part 22 may be arranged only on one side or the other side in the X direction with respect to the first heat dissipation part 21.

[0189] (Other embodiments)

[0190] In the above embodiments, the heat sink 20 provided in the semiconductor module 1 is arranged so that the plurality of heat sinks are arranged in a straight line, but the present invention is not limited thereto. For example, the plurality of heat sinks may be arranged in a bent L-shape, U-shape, or the like.

[0191] In the above-mentioned embodiments, the third virtual plane that defines the direction in which the third heat dissipation part 23 has high thermal conductivity is parallel to the direction in which the third heat dissipation part 23 is connected to the second heat dissipation part 22 and is parallel to the thickness direction, but the present invention is not limited thereto. For example, the third virtual plane may be at any angle other than perpendicular to the direction in which the third heat dissipation part 23 is connected to the second heat dissipation part 22.

[0192] In the above embodiments, the first virtual plane defining the direction in which the first heat dissipation portion 21 has high thermal conductivity is parallel to the third virtual plane defining the direction in which the third heat dissipation portion 23 has high thermal conductivity, but the present invention is not limited thereto. For example, the first virtual plane and the third virtual plane may form any angle.

[0193] The present disclosure is not limited to the above-mentioned embodiments, and can be appropriately changed within the scope described in the claims. In addition, the above-mentioned embodiments and a part thereof are not unrelated to each other, and can be appropriately combined except for the case where it is obviously impossible to combine. In addition, in the above-mentioned embodiments, the elements constituting the embodiments are not necessarily necessary, except for the case where it is specifically stated as necessary and the case where it is considered to be obviously necessary in principle. In addition, in the above-mentioned embodiments, when referring to the number, value, amount, range and other numerical values ​​of the constituent elements of the embodiments, except for the case where it is specifically stated as necessary and the case where it is obviously limited to a clear specific number in principle, it is not limited to the specific number. In addition, in the above-mentioned embodiments, when referring to the shape, positional relationship, etc. of the constituent elements, etc., except for the case where it is specifically stated and the case where it is limited to a specific shape, positional relationship, etc. in principle, it is not limited to the shape, positional relationship, etc.

Claims

1. A semiconductor module comprising a plate-shaped heat sink and a semiconductor element provided in the thickness direction of the heat sink and generating heat when energized, characterized in that: The heat sink has a first heat sink and a second heat sink formed of a material having anisotropic thermal conductivity. The first heat dissipation portion is provided to include a position opposite to the semiconductor element in the thickness direction, and has a higher thermal conductivity in an in-plane direction of an arbitrary first virtual plane parallel to the thickness direction than in a direction perpendicular to the in-plane direction of the first virtual plane. The second heat dissipation portion is connected to the first heat dissipation portion in a direction parallel to the in-plane direction of the first virtual surface and perpendicular to the thickness direction, and has a higher thermal conductivity in the in-plane direction of the second virtual surface perpendicular to the thickness direction than in the direction perpendicular to the in-plane direction of the second virtual surface.

2. The semiconductor module according to claim 1, characterized in that The second heat dissipation portion is connected to a portion of the first heat dissipation portion that extends in a direction parallel to the in-plane direction of the first virtual surface and perpendicular to the thickness direction of the heat sink relative to a position opposite to the semiconductor element, and is also connected to a portion of the first heat dissipation portion that extends in a direction perpendicular to the in-plane direction of the first virtual surface relative to a position opposite to the semiconductor element.

3. The semiconductor module according to claim 1 or 2, characterized in that The heat sink also has a third heat sink. The third heat dissipation part is connected to the second heat dissipation part in an arbitrary direction parallel to the in-plane direction of the second virtual plane, and has a higher thermal conductivity in the in-plane direction of the third virtual plane that is not perpendicular to the direction in which the third heat dissipation part is connected to the second heat dissipation part and is parallel to the thickness direction than in the direction perpendicular to the in-plane direction of the third virtual plane.

4. The semiconductor module according to claim 3, characterized in that The third virtual plane is parallel to a direction in which the third heat dissipation portion is connected to the second heat dissipation portion, and is parallel to the thickness direction.

5. The semiconductor module according to claim 3, characterized in that The first virtual plane and the third virtual plane are parallel to a direction in which the first heat dissipation portion, the second heat dissipation portion, and the third heat dissipation portion are arranged.

6. The semiconductor module according to claim 1 or 2, characterized in that: The heat sink further includes a metal plate provided on a surface facing the thickness direction or at a middle position of the heat sink in the thickness direction.

7. The semiconductor module according to claim 1 or 2, characterized in that: The heat sink further includes a plate-shaped insulator provided on a surface facing the thickness direction or at a middle position in the thickness direction of the heat sink.

8. The semiconductor module according to claim 1 or 2, characterized in that: The heat sink further includes a metal plate that covers a surface facing the thickness direction and a surface facing a direction perpendicular to the thickness direction.

9. The semiconductor module according to claim 1 or 2, characterized in that: The heat sink further includes a metal plating layer provided on a surface facing the thickness direction.

10. A heat sink, which is a plate-shaped heat sink for dissipating heat generated by a semiconductor element used in a semiconductor module, characterized in that: The semiconductor element is arranged in the thickness direction of the heat sink. The heat sink has a first heat sink and a second heat sink formed of a material having anisotropic thermal conductivity. The first heat dissipation portion is provided to include a position opposite to the semiconductor element in the thickness direction, and has a higher thermal conductivity in an in-plane direction of an arbitrary first virtual plane parallel to the thickness direction than in a direction perpendicular to the in-plane direction of the first virtual plane. The second heat dissipation portion is connected to the first heat dissipation portion in a direction parallel to the in-plane direction of the first virtual surface and perpendicular to the thickness direction, and has a higher thermal conductivity in the in-plane direction of the second virtual surface perpendicular to the thickness direction than in the direction perpendicular to the in-plane direction of the second virtual surface.

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