Semiconductor module and heat sink

Abstract

To provide a semiconductor module having high heat dissipation.SOLUTION: A semiconductor module 1 includes a heat sink 20 and a semiconductor device 10. The heat sink 20 has a first heat-radiation part 21 and a second heat-radiation parts 22 which are formed including a material with anisotropy in heat conductivity. The first heat-radiation part 21 is provided including a position that faces the semiconductor device 10 in a thickness direction of the heat sink 20, and has high heat dissipation in an in-place direction of an arbitrary first virtual surface parallel to the thickness direction of the heat sink 20. The second heat-radiation parts 22 are connected to the first heat-radiation part 21 in a direction parallel to the in-place direction of the first virtual surface and perpendicular to the thickness direction of the heat sink 20, and each have high heat conductivity in an in-place direction of a second virtual surface perpendicular to the thickness direction of the heat sink 20.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] The semiconductor module described in Patent Document 1 includes a semiconductor element and a heat sink that dissipates heat generated by the semiconductor element. In Patent Document 1, the heat sink is called a heat spreader. The heat sink in Patent Document 1 has a first heat spreader and a second heat spreader formed of graphite, which is a material with anisotropic thermal conductivity, and is formed in a rectangular shape when viewed from the thickness direction. The first heat spreader has high thermal conductivity in an in-plane direction of an arbitrary imaginary plane parallel to the plate thickness direction of the heat sink. The second heat spreader is connected to the first heat spreader in a direction perpendicular to the arbitrary imaginary plane, and has high thermal conductivity in an in-plane direction of another imaginary plane perpendicular to the arbitrary imaginary plane. The semiconductor element is arranged so as to overlap both the first heat spreader and the second heat spreader. As a result, the heat generated from the semiconductor element spreads into the heat sink via the first heat spreader and the second heat spreader, and is dissipated from the surface of the heat sink opposite to the semiconductor element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-100401 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the semiconductor module described in Patent Document 1 is configured such that the heat generated from the semiconductor element is not easily transferred to the four corners of the rectangular heat sink due to the anisotropy of the thermal conductivity of the first heat spreader and the second heat spreader and their arrangement. Therefore, this semiconductor module does not effectively utilize the entire area of ​​the heat sink, and there is room for improvement.

[0005] In view of the above, an object of the present disclosure is to provide a semiconductor module and a heat sink that are capable of improving heat dissipation. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, a semiconductor module includes a plate-shaped heat sink (20) and a semiconductor element (10) disposed in the thickness direction of the heat sink and generating heat when current is applied. The heat sink has a first heat sink section (21) and a second heat sink section (22) formed by including a material having anisotropic thermal conductivity. The first heat sink section is disposed including a position facing the semiconductor element in the thickness direction of the heat sink, and has high thermal conductivity in an in-plane direction of an arbitrary first imaginary plane parallel to the thickness direction of the heat sink. The second heat sink section is connected to the first heat sink section in a direction parallel to the in-plane direction of the first imaginary plane and perpendicular to the thickness direction of the heat sink, and has high thermal conductivity in an in-plane direction of a second imaginary plane perpendicular to the thickness direction of the heat sink.

[0007] According to this, the heat transferred from the semiconductor element to the first heat dissipation section spreads in the in-plane direction of the first imaginary plane at the position of the first heat dissipation section facing the semiconductor element. Therefore, a part of the heat transferred from the semiconductor element to the first heat dissipation section is dissipated from the surface of the first heat dissipation section opposite the semiconductor element, and the remaining part is transferred to the second heat dissipation section. The heat transferred to the second heat dissipation section spreads in the in-plane direction of the second imaginary plane perpendicular to the thickness direction of the heat dissipation plate at the second heat dissipation section. Therefore, the heat spreads within the second heat dissipation section and is transferred from the second heat dissipation section to a position other than the position of the first heat dissipation section facing the semiconductor element. The heat transferred from the second heat dissipation section to the first heat dissipation section spreads in the in-plane direction of the first imaginary plane at the first heat dissipation section and is dissipated from the surface of the first heat dissipation section opposite the semiconductor element. In this way, by providing the second heat dissipation section that functions as a heat redirection section on the outside of the first heat dissipation section, it becomes possible to spread the heat generated by the semiconductor element over almost the entire area of ​​the heat sink and dissipate the heat in the thickness direction of the heat sink. Therefore, this semiconductor module can expand the area where the heat sink functions as a heat dissipation surface, and improve the heat dissipation performance of the heat sink.

[0008] In this disclosure, "vertical" includes a substantially perpendicular state, for example, due to manufacturing tolerances, and "parallel" includes a substantially parallel state, for example, due to manufacturing tolerances. In this disclosure, "the heat dissipation section has high thermal conductivity in the in-plane direction of a predetermined imaginary plane" means that the thermal conductivity of the heat dissipation section in the in-plane direction of the predetermined imaginary plane is higher than the thermal conductivity in the direction perpendicular to the predetermined imaginary plane. The heat dissipation plate is required to have at least the first heat dissipation section and the second heat dissipation section, and may have other heat dissipation sections.

[0009] Another aspect of the present disclosure relates to a plate-shaped heat sink that dissipates heat generated by a semiconductor element (10) used in a semiconductor module. The semiconductor element is provided in the thickness direction of the heat sink. The heat sink has a first heat sink section (21) and a second heat sink section (22) formed by including a material having anisotropic thermal conductivity. The first heat sink section is provided including a position facing the semiconductor element in the thickness direction, and has high thermal conductivity in an in-plane direction of an arbitrary first imaginary plane parallel to the thickness direction. The second heat sink section is connected to the first heat sink section in a direction parallel to the in-plane direction of the first imaginary plane and perpendicular to the thickness direction, and has high thermal conductivity in an in-plane direction of a second imaginary plane perpendicular to the thickness direction.

[0010] According to this, the heat sink from another viewpoint also spreads the heat generated by the semiconductor element over almost the entire area of ​​the heat sink, as explained in the above one viewpoint, and can dissipate the heat in the thickness direction of the heat sink. Therefore, the semiconductor module using this heat sink can improve the heat dissipation performance.

[0011] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and specific components described in the embodiments described below. [Brief description of the drawings]

[0012] [Figure 1] 1 is a perspective view of a semiconductor module and a cooler according to a first embodiment. FIG. [Diagram 2] 2 is a plan view of the semiconductor module as seen in the direction of the arrow II in FIG. [Diagram 3] FIG. 1 is a schematic diagram showing the molecular structure of graphite. [Figure 4] FIG. 2 is a plan view of a semiconductor module of a first comparative example. [Diagram 5] 4 is an explanatory diagram illustrating how heat is transferred when a semiconductor element generates heat in the semiconductor module of the first comparative example. FIG. [Figure 6] 13 is an explanatory diagram illustrating how heat is transferred when a semiconductor element generates heat in a semiconductor module of a second comparative example. FIG. [Figure 7]FIG. 11 is a perspective view of a semiconductor module according to a second embodiment. [Figure 8] 8 is a plan view of the semiconductor module as seen in the direction of the arrow VIII in FIG. 7. [Figure 9] FIG. 13 is a perspective view of a semiconductor module according to a third embodiment. [Figure 10] 10 is a plan view of the semiconductor module as viewed in the X direction of FIG. 9. [Figure 11] FIG. 13 is a plan view of a semiconductor module according to a fourth embodiment. [Figure 12] FIG. 13 is a plan view of a semiconductor module according to a fifth embodiment. [Figure 13] FIG. 13 is a plan view of a semiconductor module according to a sixth embodiment. [Figure 14] FIG. 13 is a plan view of a semiconductor module according to a seventh embodiment. [Figure 15] FIG. 13 is a plan view of a semiconductor module according to an eighth embodiment. [Figure 16] FIG. 13 is a perspective view of a semiconductor module according to a ninth embodiment. [Figure 17] FIG. 23 is a perspective view of a semiconductor module according to a tenth embodiment. [Figure 18] FIG. 23 is a perspective view of a semiconductor module according to an eleventh embodiment. [Figure 19] FIG. 23 is a perspective view of a semiconductor module according to a twelfth embodiment. [Figure 20] FIG. 23 is a plan view of a semiconductor module according to a thirteenth embodiment. [Figure 21] FIG. 23 is a plan view of a semiconductor module according to a fourteenth embodiment. [Figure 22] FIG. 23 is a perspective view of a semiconductor module according to a fifteenth embodiment. [Diagram 23] 23 is a diagram illustrating an analysis of temperature distribution when a semiconductor element generates heat in a plan view of a semiconductor module according to a fifteenth embodiment. FIG. [Figure 24] 24 is a cross-sectional view taken along line XXIV-XXIV in FIG. 23, showing an analysis of temperature distribution when a semiconductor element generates heat. [Diagram 25]FIG. 13 is a perspective view of a semiconductor module of a third comparative example. [Figure 26] 13 is a diagram illustrating an analysis of temperature distribution when a semiconductor element generates heat in a plan view of the semiconductor module of the third comparative example. FIG. [Figure 27] FIG. 27 is an analysis of temperature distribution when a semiconductor element generates heat, in a cross-sectional view taken along line XXVII-XXVII in FIG. 26. [Figure 28] FIG. 23 is a perspective view of a semiconductor module according to a sixteenth embodiment. [Figure 29] 23 is a cross-sectional view parallel to the thickness direction of a heat sink in a semiconductor module according to a seventeenth embodiment. FIG. [Diagram 30] FIG. 23 is a perspective view of a semiconductor module according to an eighteenth embodiment. [Diagram 31] 23 is a cross-sectional view parallel to the thickness direction of a heat sink in a semiconductor module according to an eighteenth embodiment. FIG. [Diagram 32] 23 is a cross-sectional view parallel to the thickness direction of a heat sink in a semiconductor module according to a nineteenth embodiment. FIG. [Diagram 33] FIG. 20 is a perspective view of a semiconductor module and a cooler according to a twentieth embodiment. [Diagram 34] 34 is a plan view of the semiconductor module as seen in the direction of the arrow XXXIV in FIG. 33. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals, and the description thereof will be omitted.

[0014] (First embodiment) A first embodiment will be described with reference to the drawings. As shown in Figures 1 and 2, a semiconductor module 1 of the first embodiment includes a semiconductor element 10, a heat sink 20, and the like.

[0015] The semiconductor element 10 is a heat generating element that generates heat when electricity is applied, and is, for example, a power semiconductor element such as a diode, a MOSFET, or an IGBT. Note that MOSFET is an abbreviation for Metal-Oxide-Semiconductor Field Effect Transistor, and IGBT is an abbreviation for Insulated Gate Bipolar Transistor. Power semiconductor elements are made of, for example, silicon (Si), silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga 2 O 3 ) The semiconductor element 10 is provided on one surface of the heat sink 20 facing in the thickness direction (hereinafter referred to as the "element mounting side").

[0016] The heat sink 20 is formed in a plate shape. For example, a cooler 30 is disposed on the surface of the heat sink 20 opposite to the element mounting side (hereinafter referred to as the "cooling surface"). Note that a heat sink or a heat exchanger may be disposed instead of or together with the cooler 30. Heat generated by the semiconductor element 10 spreads over the heat sink 20 and is dissipated from the cooling surface.

[0017] The heat dissipation plate 20 has a first heat dissipation section 21, a second heat dissipation section 22, and a third heat dissipation section 23. In the description of the first embodiment and the figures referred to in the description, in addition to the numerals 22, 23 indicating the second heat dissipation section 22 and the third heat dissipation section 23, alphabetical symbols R, L indicating the position of each heat dissipation section are added to the end of the numerals. This is the same in the description of the fourth to twelfth and fifteenth to twentieth embodiments described later and the figures referred to in the description.

[0018] In the first embodiment, two second heat dissipation sections 22R, 22L and two third heat dissipation sections 23R, 23L are arranged on the right and left sides of the paper surface of the figure, sandwiching the first heat dissipation section 21. The first heat dissipation section 21, the second heat dissipation section 22, and the third heat dissipation section 23 are all formed containing a material having anisotropic thermal conductivity. The material having anisotropic thermal conductivity is, for example, graphite.

[0019] As shown in FIG. 3, the molecular structure of graphite 2 is a structure in which a plurality of graphenes 3, in which a hexagonal lattice structure in which carbon atoms are bonded spreads two-dimensionally, are stacked in layers. In graphite 2, the thermal conductivity in the in-plane direction of graphene 3 is higher than the thermal conductivity in the stacking direction of the plurality of graphenes 3. Specifically, in the three-dimensional coordinate system of a-axis, b-axis, and c-axis shown in FIG. 3, graphite 2 has high thermal conductivity in the in-plane direction of the ab-plane and low thermal conductivity in the direction in which the c-axis extends (hereinafter referred to as the "c-direction"). In general, graphite 2 has a thermal conductivity of about 1700 W / m·K in the in-plane direction of the ab-plane and a thermal conductivity of about 7 W / m·K in the c-direction. Note that 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, it is possible to configure a heat sink 20 with higher heat dissipation performance than a copper plate.

[0020] 1 and 2, the layers of the graphene 3 constituting the graphite 2 in the first heat dissipation section 21, the second heat dissipation section 22, and the third heat dissipation section 23 are shown by dashed lines. In FIG. 1 and FIG. 2, the boundaries of the first heat dissipation section 21, the second heat dissipation section 22, and the third heat dissipation section 23 are shown by solid lines, but in reality, the first heat dissipation section 21, the second heat dissipation section 22, and the third heat dissipation section 23 are integrally formed. In addition, in the three-dimensional coordinates based on the X-axis, the Y-axis, and the Z-axis shown in FIG. 1 and FIG. 2, the direction in which the Z-axis extends coincides with the thickness direction of the heat dissipation plate 20. In addition, the direction in which the first heat dissipation section 21, the second heat dissipation section 22, and the third heat dissipation section 23 are arranged coincides 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 also apply to the descriptions of the second to twentieth embodiments and the first to third comparative examples described below, and to the drawings referred to in the descriptions.

[0021] 1 and 2, the first heat dissipation portion 21 is a portion provided including a position facing 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 facing the semiconductor element 10 in the thickness direction of the heat dissipation plate 20 is referred to as "the position of the first heat dissipation portion 21 directly below the semiconductor element 10."

[0022] The first heat dissipation section 21 has high thermal conductivity in an in-plane direction of a first imaginary plane, which is an arbitrary plane parallel to the thickness direction of the heat dissipation plate 20. In the first embodiment, the first imaginary plane is the XZ plane. Therefore, the first heat dissipation section 21 has high thermal conductivity in the in-plane direction of the XZ plane. Note that the first heat dissipation section 21 has a portion extending from a position directly below the semiconductor element 10 in a direction perpendicular to the in-plane direction of the first imaginary plane, in addition to the position directly below the semiconductor element 10.

[0023] The second heat dissipation section 22 is a portion connected to the first heat dissipation section 21 in a direction parallel to the in-plane direction of the first imaginary plane and perpendicular to the thickness direction. Specifically, the second heat dissipation section 22 is a portion connected to the first heat dissipation section 21 in the X direction. More specifically, the second heat dissipation section 22 is connected to a portion of the first heat dissipation section 21 that is parallel to the in-plane direction of the first imaginary plane and perpendicular to the thickness direction of the heat dissipation plate with respect to a position directly below the semiconductor element 10. At the same time, the second heat dissipation section 22 is also connected to a portion of the first heat dissipation section 21 that extends in a direction perpendicular to the in-plane direction of the first imaginary plane with respect to a position directly below the semiconductor element 10. That is, the second heat dissipation section 22 is connected to a portion of the first heat dissipation section 21 in the X direction with respect to a position directly below the semiconductor element 10, and is also connected in the X direction to a portion of the first heat dissipation section 21 that extends in the Y direction from a position directly below the semiconductor element 10.

[0024] In the first embodiment, the heat dissipation plate 20 has two second heat dissipation sections 22. Of the two second heat dissipation sections 22, the one arranged on one side in the X direction with respect to the first heat dissipation section 21 is called the one-side second heat dissipation section 22R, and the one arranged on the other side in the X direction with respect to the first heat dissipation section 21 is called the other-side second heat dissipation section 22L.

[0025] The second heat dissipation section 22 has high thermal conductivity in an in-plane direction of a second imaginary plane perpendicular to the thickness direction of the heat dissipation plate 20. In the first embodiment, the second imaginary plane is the XY plane. Therefore, the second heat dissipation section 22 has high thermal conductivity in the in-plane direction of the XY plane.

[0026] The third heat dissipation section 23 is a portion connected to the second heat dissipation section 22 in any direction parallel to the in-plane direction of the second imaginary plane. In the first embodiment, the first heat dissipation section 21, the second heat dissipation section 22, and the third heat dissipation section 23 are arranged in the X direction. Therefore, the third heat dissipation section 23 is a portion connected to the second heat dissipation section 22 in the X direction. In the first embodiment, the heat dissipation plate 20 has two third heat dissipation sections 23. Of the two third heat dissipation sections 23, the one arranged on one side in the X direction with respect to the one-side second heat dissipation section 22R is called the one-side third heat dissipation section 23R, and the one arranged on the other side in the X direction with respect to the other-side second heat dissipation section 22L is called the other-side third heat dissipation section 23L.

[0027] Here, a plane that is not perpendicular to the direction in which the third heat dissipation section 23 is connected to the second heat dissipation section 22 and is parallel to the thickness direction of the heat dissipation plate 20 is referred to as a third imaginary plane. The third heat dissipation section 23 has high thermal conductivity in the in-plane direction of the third imaginary plane. In the first embodiment, the third imaginary plane is a plane that is parallel to the direction in which the third heat dissipation section 23 is connected to the second heat dissipation section 22 and is parallel to the thickness direction of the heat dissipation plate 20. Therefore, the third imaginary plane is an XZ plane like the first imaginary plane. Therefore, the third heat dissipation section 23 has high thermal conductivity in the in-plane direction of the XZ plane.

[0028] In FIG. 2, a part of the path along which heat generated from the semiconductor element 10 is transmitted through the heat sink 20 is shown diagrammatically by arrows.

[0029] The heat generated from the semiconductor element 10 is transferred to a position of the first heat dissipation section 21 directly below the semiconductor element 10, and then transferred from that position to the second heat dissipation section 22 in the X direction, as shown by the arrow T1 in Fig. 2. The heat then spreads along the XY plane in the second heat dissipation section 22. Note that, although the arrows are omitted, a portion of the heat transferred from the semiconductor element 10 to the position of the first heat dissipation section 21 directly below the semiconductor element 10 spreads along the XZ plane at the position of the first heat dissipation section 21 directly below the semiconductor element 10, and is dissipated from the cooling surface of the first heat dissipation section 21.

[0030] As indicated by arrow T2, a part of the heat that has spread along the XY plane in second heat dissipation section 22 is transferred to third heat dissipation section 23. Then, the heat spreads along the XZ plane in third heat dissipation section 23, and is dissipated from the cooling surface of third heat dissipation section 23.

[0031] As indicated by arrow T3, another portion of the heat that has spread along the XY plane in second heat dissipation section 22 is conducted to a portion of first heat dissipation section 21 extending in the Y direction relative to a position directly below semiconductor element 10. Then, the heat spreads along the XZ plane in the portion of first heat dissipation section 21 extending in the Y direction relative to a position directly below semiconductor element 10, and is dissipated from the cooling surface of first heat dissipation section 21.

[0032] In this way, in the first embodiment, by using the second heat dissipation section 22 as a heat redirection section, it is possible to spread the heat generated by the semiconductor element 10 over substantially the entire area of ​​the heat sink 20 and dissipate the heat from the cooling surface of the heat sink 20. Therefore, in this semiconductor module 1, the area over which the heat sink 20 functions as a heat dissipation surface can be expanded, and the heat dissipation performance of the heat sink 20 can be improved.

[0033] Next, for comparison with the semiconductor module 1 described in the first embodiment, semiconductor modules of a first comparative example and a second comparative example will be described.

[0034] (First Comparative Example) As shown in FIG. 4, the heat sink 20 of the semiconductor module 101 of the first comparative example has four heat dissipation sections arranged radially around the semiconductor element 10. For ease of explanation, the heat dissipation section arranged on the right side of the plane of FIG. 4 with respect to the semiconductor element 10 is called the right heat dissipation section 41, and the heat dissipation section arranged on the left side of the plane of FIG. 4 with respect to the conductor module is called the left heat dissipation section 42. The heat dissipation section arranged on the upper side of the plane of FIG. 4 with respect to the semiconductor element 10 is called the upper heat dissipation section 43, and the heat dissipation section arranged on the lower side of the plane of FIG. 4 with respect to the conductor module is called the lower heat dissipation section 44. In FIG. 4 and FIG. 5, the boundary lines of the four heat dissipation sections 41 to 44 that are below the semiconductor element 10 are indicated by dashed lines.

[0035] The right heat dissipation section 41 and the left heat dissipation section 42 have high thermal conductivity in the in-plane direction of the XZ plane. The upper heat dissipation section 43 and the lower heat dissipation section 44 have high thermal conductivity in the in-plane direction of the YZ plane.

[0036] In FIG. 5, a part of the path of heat generated from the semiconductor element 10 and transmitted through the heat sink 20 is shown diagrammatically by arrows.

[0037] As indicated by arrow T4 in Fig. 5, heat generated from the semiconductor element 10 is transferred in the X direction in the right heat dissipation section 41 and the left heat dissipation section 42 within the range of the width of the semiconductor element 10. Also, as indicated by arrow T5 in Fig. 5, heat generated from the semiconductor element 10 is transferred in the Y direction in the range of the width of the semiconductor element 10 in the upper heat dissipation section 43 and the left heat dissipation section 42. Therefore, as indicated by hatching LT in Fig. 5, outside the region where heat is transferred in the X and Y directions within the range of the width of the semiconductor element 10, a region where almost no heat is transferred is formed. Therefore, the semiconductor module 101 of the first comparative example is unable to effectively utilize the entire region of the heat sink 20.

[0038] (Second Comparative Example) As shown in FIG. 6, the semiconductor module 102 of the second comparative example has the same configuration as that of the above-mentioned Patent Document 1. The heat sink 20 of the semiconductor module 102 of the second comparative example has three heat dissipation sections. For convenience of explanation, the heat dissipation section that includes the position directly below the semiconductor element 10 and extends in the Y direction among the three heat dissipation sections is called the vertical heat dissipation section 45. The heat dissipation section arranged on the right side of the vertical heat dissipation section 45 in FIG. 6 is called the right horizontal heat dissipation section 46, and the heat dissipation section arranged on the left side of the vertical heat dissipation section 45 in FIG. 6 is called the left horizontal heat dissipation section 47. In FIG. 6, the boundary lines of the three heat dissipation sections 45 to 47 that are located below the semiconductor element 10 are indicated by dashed lines.

[0039] The vertical heat dissipation section 45 has high thermal conductivity in the in-plane direction of the YZ plane. The right and left horizontal heat dissipation sections 46 and 47 have high thermal conductivity in the in-plane direction of the XZ plane. The semiconductor element 10 is disposed such that at least a portion of the semiconductor element 10 overlaps the vertical heat dissipation section 45, the right and left horizontal heat dissipation sections 46 and 47 in the thickness direction of the heat sink 20.

[0040] In FIG. 6, a part of the path of heat generated from the semiconductor element 10 and transmitted through the heat sink 20 is shown diagrammatically by arrows.

[0041] As shown by arrow T6 in Fig. 6, heat generated from the semiconductor element 10 is transferred in the Y direction in the vertical heat dissipation section 45 within the range of the width of the semiconductor element 10. Also, as shown by arrow T7 in Fig. 6, heat generated from the semiconductor element 10 is transferred in the X direction in the right horizontal heat dissipation section 46 and the left horizontal heat dissipation section 47 within the range of the width of the semiconductor element 10. Therefore, as shown by hatching LT in Fig. 6, outside the region where heat is transferred in the X and Y directions within the range of the width of the semiconductor element 10, a region where almost no heat is transferred is formed. Therefore, the semiconductor module 102 of the second comparative example also fails to effectively utilize the entire region of the heat sink 20.

[0042] Compared to the above-mentioned first and second comparative examples, the semiconductor module 1 of the first embodiment provides the following advantages. (1) In the first embodiment, the heat sink 20 included in the semiconductor module 1 has a first heat dissipation section 21 and a second heat dissipation section 22 formed by including a material having anisotropic thermal conductivity. The first heat dissipation section 21 is provided including a position facing the semiconductor element 10 in the thickness direction of the heat sink 20, and has high thermal conductivity in an in-plane direction of an arbitrary first imaginary plane parallel to the thickness direction of the heat sink 20. The second heat dissipation section 22 is connected to the first heat dissipation section 21 in a direction parallel to the in-plane direction of the first imaginary plane and perpendicular to the thickness direction of the heat sink 20, and has high thermal conductivity in an in-plane direction of a second imaginary plane perpendicular to the thickness direction of the heat sink 20.

[0043] According to this, the heat transferred from the semiconductor element 10 to the first heat dissipation section 21 spreads in the in-plane direction of the first imaginary plane at a position of the first heat dissipation section 21 directly below the semiconductor element 10. Therefore, a part of the heat transferred from the semiconductor element 10 to the first heat dissipation section 21 is dissipated from the cooling surface of the first heat dissipation section 21, and the remaining part is transferred to the second heat dissipation section 22. As shown by the arrow T1 in FIG. 2, the heat transferred to the second heat dissipation section 22 spreads in the in-plane direction of the second imaginary plane perpendicular to the thickness direction of the heat sink 20 at the second heat dissipation section 22. As shown by the arrow T3 in FIG. 2, the heat is transferred from the second heat dissipation section 22 to a part of the first heat dissipation section 21 extending in the Y direction relative to the position directly below the semiconductor element 10. The heat transferred from the second heat dissipation section 22 to the first heat dissipation section 21 spreads in the in-plane direction of the first imaginary plane in the first heat dissipation section 21, and is dissipated from the cooling surface of the first heat dissipation section 21. In this way, in the first embodiment, by providing the second heat dissipation section 22 functioning as a heat redirection section on the outside of the first heat dissipation section 21, it is possible to spread the heat generated by the semiconductor element 10 over a wide range of the heat dissipation plate 20 and dissipate the heat from the cooling surface of the heat dissipation plate 20. Therefore, in this semiconductor module 1, the area in which the heat dissipation plate 20 functions as a heat dissipation surface is enlarged, and the heat dissipation performance of the heat dissipation plate 20 can be improved.

[0044] (2) 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 imaginary plane with respect to a position directly below the semiconductor element 10 and perpendicular to the thickness direction of the heat dissipation plate 20. At the same time, 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 imaginary plane with respect to a position directly below the semiconductor element 10. 2, it is possible for heat transferred from the semiconductor element 10 to the first heat dissipation portion 21 to be transferred to the second heat dissipation portion 22 and spread within the second heat dissipation portion 22. Then, as shown by the arrow T3 in Fig. 2, it is possible for the heat that has spread within the second heat dissipation portion 22 to be transferred from the second heat dissipation portion 22 to a portion of the first heat dissipation portion 21 that extends in the Y direction with respect to a position directly below the semiconductor element 10.

[0045] (3) In the first embodiment, the heat sink 20 further includes a third heat dissipation section 23. The third heat dissipation section 23 is connected to the second heat dissipation section 22 in an arbitrary direction parallel to the in-plane direction of the second imaginary plane. The third heat dissipation section 23 has high thermal conductivity in the in-plane direction of the third imaginary plane that is not perpendicular to the direction in which the third heat dissipation section 23 is connected to the second heat dissipation section 22 and is parallel to the thickness direction of the heat sink 20. 2, the heat that spreads from the semiconductor element 10 through the first heat dissipation section 21 into the second heat dissipation section 22 is transferred to the third heat dissipation section 23. The heat spreads in the third heat dissipation section 23 in the in-plane direction of a third imaginary plane parallel to the thickness direction of the heat dissipation plate 20, and is dissipated from the cooling surface of the third heat dissipation section 23. In this way, in the first embodiment, by providing the third heat dissipation section 23 on the opposite side of the second heat dissipation section 22 from the first heat dissipation section 21, it is possible to increase the amount of heat transferred from the heat dissipation plate 20 to the cooler 30. Therefore, in this semiconductor module 1, the area in which the heat dissipation plate 20 functions as a heat dissipation surface is expanded, and the heat dissipation performance of the heat dissipation plate 20 can be improved.

[0046] (4) In the first embodiment, the third imaginary plane that determines the direction in which the third heat dissipation section 23 has high thermal conductivity is parallel to the direction in which the third heat dissipation section 23 is connected to the second heat dissipation section 22 and is parallel to the thickness direction. According to this, when the heat sink 20 is, for example, rectangular, it is possible to prevent the formation of areas in the third heat sink 23 where heat is difficult to transmit, and to transmit the heat transmitted from the semiconductor element 10 to the first heat sink 21 to the entire third heat sink 23 via the second heat sink 22. Therefore, the heat dissipation performance of the heat sink 20 can be improved.

[0047] (5) In the first embodiment, a first imaginary plane that determines the direction in which the first heat dissipation section 21 has high thermal conductivity and a third imaginary plane that determines the direction in which the third heat dissipation section 23 has high thermal conductivity are parallel to the direction in which the first heat dissipation section 21, the second heat dissipation section 22, and the third heat dissipation section 23 are arranged. According to this, by making the orientation of the virtual plane that defines the direction having high thermal conductivity in the first heat dissipation section 21 and the third heat dissipation section 23, specifically the orientation of the multiple graphene 3 layers that make up the graphite 2, the configuration of the heat dissipation plate 20 can be simplified, and the manufacturing process can be simplified. Furthermore, when the heat sink 20 is, for example, rectangular, it is possible to prevent the formation of areas in the third heat sink 23 where heat is difficult to transmit, and to transmit the heat transmitted from the semiconductor element 10 to the first heat sink 21 to the entire third heat sink 23 via the second heat sink 22. Therefore, the heat dissipation performance of the heat sink 20 can be improved.

[0048] Second embodiment The second embodiment will be described. The second embodiment is different from the first embodiment in that a part of the configuration of the heat sink 20 is changed, and the rest is the same as the first embodiment, so only the parts that are different from the first embodiment will be described. Note that in the figures referred to in the explanation of the second embodiment and thereafter, illustrations of the cooler 30 and the like are omitted.

[0049] 7 and 8, in the second embodiment, the heat dissipation plate 20 has a first heat dissipation section 21 to a fifth heat dissipation section 25. In the explanation of the second embodiment and the figures referred to in the explanation, in addition to the numeral symbols 22 to 25 indicating the second heat dissipation section 21 to the fifth heat dissipation section 25, alphabet symbols R and L are added to the end of the numeral symbols to indicate the position of each heat dissipation section. This is the same in the explanation of the third embodiment described later and the figures referred to in the explanation.

[0050] The first heat dissipation section 21, the second heat dissipation section 22, and the third heat dissipation section 23 are the same as those described in the first embodiment. The fourth heat dissipation section 24 is a section connected to the third heat dissipation section 23 in a direction parallel to the in-plane direction of the third imaginary plane and perpendicular to the thickness direction of the heat dissipation plate 20. Specifically, the fourth heat dissipation section 24 is a section connected to the third heat dissipation section 23 in the X direction. In the second embodiment, the heat dissipation plate 20 has two fourth heat dissipation sections 24. Of the two fourth heat dissipation sections 24, the one arranged on one side in the X direction with respect to the one-side third heat dissipation section 23R is referred to as the one-side fourth heat dissipation section 24R, and the one arranged on the other side in the X direction with respect to the other-side third heat dissipation section 23L is referred to as the other-side fourth heat dissipation section 24L.

[0051] Similar to the second heat dissipation section 22, the fourth heat dissipation section 24 has high thermal conductivity in the in-plane direction of a fourth imaginary plane perpendicular to the thickness direction of the heat dissipation plate 20, i.e., the XY plane. Therefore, similar to the second heat dissipation section 22, the fourth heat dissipation section 24 functions as a heat redirection section.

[0052] The fifth heat dissipation section 25 is a portion connected to the fourth heat dissipation section 24 in any direction parallel to the in-plane direction of the fourth imaginary plane, i.e., the XY plane. In the second embodiment, the first heat dissipation section 21 to the fifth heat dissipation section 25 are all provided to be aligned in the X direction. The fifth heat dissipation section 25 is a portion connected to the fourth heat dissipation section 24 in the X direction. In the second embodiment, the heat dissipation plate 20 has two fifth heat dissipation sections 25. Of the two fifth heat dissipation sections 25, the one disposed on one side in the X direction relative to the one-side fourth heat dissipation section 24R is called the one-side fifth heat dissipation section 25R, and the one disposed on the other side in the X direction relative to the other-side fourth heat dissipation section 24L is called the other-side fifth heat dissipation section 25L.

[0053] Here, a plane that is not perpendicular to the direction in which the fifth heat dissipation section 25 is connected to the fourth heat dissipation section 24 and is parallel to the thickness direction of the heat dissipation plate 20 is called a fifth imaginary plane. The fifth heat dissipation section 25 has high thermal conductivity in the in-plane direction of the fifth imaginary plane. In the second embodiment, the fifth imaginary plane is a plane that is parallel to the direction in which the fifth heat dissipation section 25 is connected to the fourth heat dissipation section 24 and is parallel to the thickness direction of the heat dissipation plate 20. Therefore, the fifth imaginary plane is an XZ plane, like the first imaginary plane and the third imaginary plane. Therefore, the fifth heat dissipation section 25 has high thermal conductivity in the in-plane direction of the XZ plane.

[0054] In FIG. 8, a part of the path along which heat generated from the semiconductor element 10 is transmitted through the heat sink 20 is shown diagrammatically by arrows.

[0055] The heat transfer paths indicated by the arrows T1 to T3 in FIG. 8 are similar to those described in the first embodiment.

[0056] As indicated by arrow T8, the heat transferred from the third heat dissipation section 23 to the fourth heat dissipation section 24 spreads along the XY plane at the fourth heat dissipation section 24. As indicated by arrow T9, a part of the heat that spreads along the XY plane at the fourth heat dissipation section 24 is transferred to the fifth heat dissipation section 25 in the X direction, and then spreads along the XZ plane at the fifth heat dissipation section 25 and is dissipated from the cooling surface of the fifth heat dissipation section 25. In addition, as indicated by arrow T10, another part of the heat that spreads along the XY plane at the fourth heat dissipation section 24 is transferred to the third heat dissipation section 23 in the X direction, and is dissipated from the cooling surface of the third heat dissipation section 23.

[0057] In this way, in the second embodiment, by using the second heat dissipation section 22 and the fourth heat dissipation section 24 as heat redirection sections, the heat generated by the semiconductor element 10 can be spread over substantially the entire area of ​​the heat dissipation plate 20 and dissipated from the cooling surface of the heat dissipation plate 20. Therefore, in this semiconductor module 1, the area in which the heat dissipation plate 20 functions as a heat dissipation surface can be expanded, and the heat dissipation performance of the heat dissipation plate 20 can be improved.

[0058] Third embodiment The third embodiment will be described. The third embodiment is similar to the first embodiment except that a part of the configuration of the heat sink 20 is changed, and therefore only the parts different from the first embodiment will be described.

[0059] 9 and 10, in the third embodiment, the heat dissipation plate 20 has a first heat dissipation section 21 to a fourth heat dissipation section 24. The first heat dissipation section 21 to the fourth heat dissipation section 24 are the same as those described in the second embodiment.

[0060] In FIG. 10, a part of the path along which heat generated from the semiconductor element 10 is transmitted through the heat sink 20 is shown diagrammatically by arrows.

[0061] The heat transfer paths indicated by the arrows T1 to T3 in FIG. 8 are similar to those described in the first embodiment. As indicated by arrow T11, the heat transferred from the third heat dissipation section 23 to the fourth heat dissipation section 24 spreads along the XY plane at the fourth heat dissipation section 24. As indicated by arrow T12, the heat that has spread along the XY plane at the fourth heat dissipation section 24 is transferred to the third heat dissipation section 23 in the X direction. Then, the heat spreads along the XZ plane in the third heat dissipation section 23, and is dissipated from the cooling surface of the third heat dissipation section 23.

[0062] In this way, also in the third embodiment, by using the second heat dissipation section 22 and the fourth heat dissipation section 24 as heat redirection sections, it is possible to spread the heat generated by the semiconductor element 10 over substantially the entire area of ​​the heat dissipation plate 20 and dissipate the heat from the cooling surface of the heat dissipation plate 20. Therefore, in this semiconductor module 1, the area in which the heat dissipation plate 20 functions as a heat dissipation surface can be expanded, and the heat dissipation performance of the heat dissipation plate 20 can be improved.

[0063] (Fourth to Eighth Embodiments) The fourth to eighth embodiments are similar to the first embodiment except for the shape of the heat sink 20, and therefore only the differences from the first embodiment will be described.

[0064] (Fourth embodiment) 11, in the fourth embodiment, the heat dissipation plate 20 has a circular shape in a plan view seen from the thickness direction. The outer edges of the first heat dissipation portion 21, the second heat dissipation portion 22, and the third heat dissipation portion 23 are all arc-shaped. 11. The area of ​​second heat dissipation section 22R arranged on the right side of first heat dissipation section 21 in Fig. 11 is the same as the area of ​​second heat dissipation section 22L arranged on the left side of first heat dissipation section 21 in Fig. 11. The area of ​​third heat dissipation section 23R arranged on the right side of first heat dissipation section 21 in Fig. 11 is the same as the area of ​​third heat dissipation section 23L arranged on the left side of first heat dissipation section 21 in Fig. 11.

[0065] Fifth embodiment 12, in the fifth embodiment, the heat dissipation plate 20 has a triangular shape in a plan view seen from the thickness direction thereof. Two of the three vertices of the triangle are formed in the third heat dissipation section 23R disposed on the right side of the paper in FIG. 12, and the other vertex is formed in the third heat dissipation section 23L disposed on the left side of the paper in FIG.

[0066] 12. The area of ​​second heat dissipation section 22R arranged on the right side of first heat dissipation section 21 in Fig. 12 is larger than the area of ​​second heat dissipation section 22L arranged on the left side of first heat dissipation section 21 in Fig. 12. The area of ​​third heat dissipation section 23R arranged on the right side of first heat dissipation section 21 in Fig. 12 is larger than the area of ​​third heat dissipation section 23L arranged on the left side of first heat dissipation section 21 in Fig. 12.

[0067] Sixth embodiment As shown in Fig. 13, in the sixth embodiment, the heat dissipation plate 20 has a triangular shape in a plan view seen from the thickness direction. The three vertices of the triangle are formed in a portion of the first heat dissipation section 21 on the upper side of the paper in Fig. 13, in the third heat dissipation section 23R disposed on the right side of the paper in Fig. 13, and in the third heat dissipation section 23L disposed on the left side of the paper in Fig. 13.

[0068] 13. The area of ​​second heat dissipation section 22R arranged on the right side of first heat dissipation section 21 in Fig. 13 is the same as the area of ​​second heat dissipation section 22L arranged on the left side of first heat dissipation section 21 in Fig. 13. The area of ​​third heat dissipation section 23R arranged on the right side of first heat dissipation section 21 in Fig. 13 is the same as the area of ​​third heat dissipation section 23L arranged on the left side of first heat dissipation section 21 in Fig. 13.

[0069] Seventh embodiment 14, in the seventh embodiment, the heat sink 20 has a rectangular shape in a plan view seen from the thickness direction. Specifically, the heat sink 20 has a rectangular shape with the length of the side in the X direction longer than the length of the side in the Y direction. Although not shown in the drawings, the heat sink 20 may have a rectangular shape with the length of the side in the X direction shorter than the length of the side in the Y direction.

[0070] Eighth embodiment As shown in Fig. 15, in the eighth embodiment, the heat dissipation plate 20 has a hexagonal shape in a plan view seen from its thickness direction. Specifically, the third heat dissipation section 23R disposed on the right side of the paper in Fig. 15 relative to the first heat dissipation section 21 has a central portion in the Y direction protruding to the right in the X direction. Also, the third heat dissipation section 23L disposed on the left side of the paper in Fig. 15 relative to the first heat dissipation section 21 has a central portion in the Y direction protruding to the left in the X direction. Three of the six vertices of the hexagon are formed in the third heat dissipation section 23R disposed on the right side of the paper in Fig. 15, and the other three vertices are formed in the third heat dissipation section 23L disposed on the left side of the paper in Fig. 15.

[0071] 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 ellipse or a polygon can be used.

[0072] (Ninth to Twelfth Embodiments) The ninth to twelfth embodiments are different from the first embodiment in the shape or mounting position of the semiconductor element 10, but are otherwise similar to the first embodiment, so only the parts that differ from the first embodiment will be described.

[0073] Ninth embodiment 16 , in the ninth embodiment, at least a portion of the semiconductor element 10 is provided to overlap 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 provided so that not only the first heat dissipation portion 21 but also a portion of it overlaps the second heat dissipation portion 22.

[0074] Tenth embodiment 17, in the tenth embodiment, a plurality of semiconductor elements 10 are provided on a heat sink 20. Specifically, two semiconductor elements 10 are both provided on a first heat dissipation portion 21. In this manner, a plurality of semiconductor elements 10 may be mounted on the heat sink 20. Note that the number of semiconductor elements 10 is not limited to two and can be set arbitrarily, and the mounting positions thereof can also be set arbitrarily.

[0075] Eleventh embodiment 18, in the eleventh embodiment, a rectangular semiconductor element 10 is mounted. In this manner, any shape can be adopted for the semiconductor element 10. In addition, the aspect ratio of the shape of the semiconductor element 10 can also be set arbitrarily.

[0076] Twelfth embodiment 19, in the twelfth embodiment, the semiconductor element 10 is provided on the heat sink 20 at a position on the left side of the paper surface of Fig. 19. The semiconductor element 10 may be provided on one of the multiple heat dissipation parts constituting the heat sink 20, which has high thermal conductivity in an in-plane direction of any imaginary plane parallel to the thickness direction of the heat sink 20.

[0077] In the present disclosure, as described in the first embodiment, among the multiple heat dissipation sections constituting the heat sink 20, the one that is provided including a position facing the semiconductor element 10 in the thickness direction of the heat sink 20 and has high thermal conductivity in an in-plane direction of an arbitrary first imaginary plane parallel to the thickness direction of the heat sink 20 is called the first heat dissipation section 21. Therefore, in the twelfth embodiment, the heat dissipation section of the heat sink 20 that is arranged on the left side of the paper surface of Fig. 19 is called the first heat dissipation section 21, and the heat dissipation sections arranged from the first heat dissipation section 21 toward the right side of the paper surface of Fig. 19 are called the second heat dissipation section 22 to the fifth heat dissipation section 25. The second heat dissipation section 22 and the fourth heat dissipation section 24 function as heat redirection sections.

[0078] (Thirteenth and fourteenth embodiments) In the thirteenth and fourteenth embodiments, unlike the first embodiment, the multiple heat dissipation sections that make up the heat sink 20 are arranged radially around the semiconductor element 10, but are otherwise similar to the first embodiment, so only the parts that differ from the first embodiment will be described.

[0079] Thirteenth embodiment 20, in the thirteenth embodiment, the heat sink 20 included in the semiconductor module 1 has a first heat dissipation section 21, a second heat dissipation section 22, and a third heat dissipation section 23 radially arranged around the semiconductor element 10. In other words, the second heat dissipation section 22 is provided in an annular shape outside the first heat dissipation section 21, and the third heat dissipation section 23 is provided in an annular shape outside the second heat dissipation section 22. This heat sink 20 is rectangular. The first heat dissipation section 21, the second heat dissipation section 22, and the third heat dissipation section 23 are each divided into four sections by the diagonals of the rectangle.

[0080] In the description of the thirteenth embodiment and FIG. 20 referred to in the description, in addition to the numeral symbols 22-23 indicating the first heat dissipation section 21-third heat dissipation section 23, alphabet symbols a-d indicating the section of each heat dissipation section are added at the end of the numeral symbols. In FIG. 20, the boundaries of the first heat dissipation section 21, the second heat dissipation section 22, and the third heat dissipation section 23 and the boundaries of each section are all shown by solid lines, but in reality, they are formed integrally. In FIG. 20, the boundaries of each section of the first heat dissipation section 21 that are located under the semiconductor element 10 are shown by dashed lines. These are the same in the description of the fourteenth embodiment described later and FIG. 21 referred to in the description.

[0081] Each section of the first heat dissipation section 21 has high thermal conductivity in the in-plane direction of a first imaginary plane, which is an arbitrary plane parallel to the thickness direction of the heat dissipation plate 20. Specifically, of the four sections of the first heat dissipation section 21, section 21a arranged on the upper side of the paper in Fig. 20 and section 21b arranged on the lower side of the paper in Fig. 20 have high thermal conductivity in the in-plane direction of the YZ plane as the first imaginary plane. Also, of the four sections of the first heat dissipation section 21, section 21c arranged on the right side of the paper in Fig. 20 and section 21d arranged on the left side of the paper in Fig. 20 have high thermal conductivity in the in-plane direction of the XZ plane as the first imaginary plane.

[0082] Each section of the second heat dissipation section 22 is a portion that is connected to each section of the first heat dissipation section 21 in a direction parallel to the in-plane direction of the first imaginary plane and perpendicular to the thickness direction. Each section of the second heat dissipation section 22 has high thermal conductivity in the in-plane direction of the second imaginary plane perpendicular to the thickness direction of the heat dissipation plate 20. Specifically, all of the four sections 22a, 22b, 22c, and 22d of the second heat dissipation section 22 have high thermal conductivity in the in-plane direction of the XY plane as the second imaginary plane.

[0083] Each section of the third heat dissipation section 23 is a portion connected to each section of the second heat dissipation section 22 in any direction parallel to the in-plane direction of the second imaginary plane. Each section of the third heat dissipation section 23 has high thermal conductivity in the in-plane direction of the third imaginary plane that is not perpendicular to the direction in which the third heat dissipation section 23 is connected to the second heat dissipation section 22 and is parallel to the thickness direction of the heat dissipation plate 20. Specifically, of the four sections of the third heat dissipation section 23, section 23a arranged on the upper side of the paper in FIG. 20 and section 23b arranged on the lower side of the paper in FIG. 20 have high thermal conductivity in the in-plane direction of the YZ plane as the third imaginary plane. Of the four sections of the third heat dissipation section 23, section 23c arranged on the right side of the paper in FIG. 20 and section 24d arranged on the left side of the paper in FIG. 20 have high thermal conductivity in the in-plane direction of the XZ plane as the third imaginary plane.

[0084] In the thirteenth embodiment described above, by providing the second heat dissipation section 22 functioning as a heat redirection section between the first heat dissipation section 21 and the third heat dissipation section 23, it is possible to spread the heat generated by the semiconductor element 10 to almost the entire area of ​​the heat dissipation plate 20. Therefore, in this semiconductor module 1, the area in which the heat dissipation plate 20 functions as a heat dissipation surface is enlarged, and the heat dissipation performance of the heat dissipation plate 20 can be improved.

[0085] Fourteenth embodiment As shown in FIG. 21, in the 14th embodiment, the heat sink 20 of the semiconductor module 1 has a first heat dissipation section 21, a second heat dissipation section 22, and a third heat dissipation section 23 radially arranged around the semiconductor element 10. In other words, the second heat dissipation section 22 is provided in an annular shape outside the first heat dissipation section 21, and the third heat dissipation section 23 is provided in an annular shape outside the second heat dissipation section 22. The heat sink 20 is hexagonal. The first heat dissipation section 21, the second heat dissipation section 22, and the third heat dissipation section 23 are each divided into six sections by the diagonals of the hexagon. In FIG. 21, in addition to the numeral symbols 22 to 23 indicating the first heat dissipation section 21 to the third heat dissipation section 23, alphabet symbols e to j indicating the sections of each heat dissipation section are added to the end of the numeral symbols.

[0086] 21, the P axis and the Q axis are added to the three-dimensional coordinate system defined by the X axis, the Y axis, and the Z axis. The P axis is an axis rotated 30° counterclockwise with respect to the X axis in the XY plane, and the Q axis is an axis rotated 30° clockwise with respect to the X axis in the XY plane.

[0087] Each section of the first heat dissipation section 21 has high thermal conductivity in the in-plane direction of the first imaginary plane, which is an arbitrary plane parallel to the thickness direction of the heat dissipation plate 20. Specifically, among the six sections of the first heat dissipation section 21, section 21e arranged on the upper side of the paper in FIG. 21 and section 21f arranged on the lower side of the paper in FIG. 21 have high thermal conductivity in the in-plane direction of the YZ plane as the first imaginary plane. Also, among the six sections of the first heat dissipation section 21, section 21g arranged on the upper right side of the paper in FIG. 21 and section 21h arranged on the lower left side of the paper in FIG. 21 have high thermal conductivity in the in-plane direction of the PZ plane as the first imaginary plane. Also, among the six sections of the first heat dissipation section 21, section 21i arranged on the lower right side of the paper in FIG. 21 and section 21j arranged on the upper left side of the paper in FIG. 21 have high thermal conductivity in the in-plane direction of the QZ plane as the first imaginary plane.

[0088] Each section of the second heat dissipation section 22 is a portion connected to each section of the first heat dissipation section 21 in a direction parallel to the in-plane direction of the first imaginary plane and perpendicular to the thickness direction. Each section of the second heat dissipation section 22 has high thermal conductivity in the in-plane direction of the second imaginary plane perpendicular to the thickness direction of the heat dissipation plate 20. Specifically, all of the six sections 22e, 21f, 21g, 21h, 21i, and 21j of the second heat dissipation section 22 have high thermal conductivity in the in-plane direction of the XY plane as the second imaginary plane.

[0089] The third heat dissipation section 23 is a portion connected to the second heat dissipation section 22 in an arbitrary direction parallel to the in-plane direction of the second imaginary plane. The third heat dissipation section 23 has high thermal conductivity in the in-plane direction of the third imaginary plane that is not perpendicular to the direction in which the third heat dissipation section 23 is connected to the second heat dissipation section 22 and is parallel to the thickness direction of the heat dissipation plate 20. Specifically, of the six sections of the third heat dissipation section 23, the section 23e arranged on the upper side of the paper in FIG. 21 and the section 23f arranged on the lower side of the paper in FIG. 21 have high thermal conductivity in the in-plane direction of the YZ plane as the third imaginary plane. Also, of the six sections of the third heat dissipation section 23, the section 23g arranged on the upper right side of the paper in FIG. 21 and the section 23h arranged on the lower left side of the paper in FIG. 21 have high thermal conductivity in the in-plane direction of the PZ plane as the third imaginary plane. Furthermore, of the six sections of the third heat dissipation section 23, section 23i arranged on the lower right side of the paper in FIG. 21 and section 23j arranged on the upper left side of the paper in FIG. 21 have high thermal conductivity in the in-plane direction of the QZ plane as the third imaginary plane.

[0090] In the fourteenth embodiment described above, by providing the second heat dissipation section 22 functioning as a heat redirection section between the first heat dissipation section 21 and the third heat dissipation section 23, it is possible to spread the heat generated by the semiconductor element 10 to almost the entire area of ​​the heat dissipation plate 20. Therefore, in this semiconductor module 1, the area in which the heat dissipation plate 20 functions as a heat dissipation surface is enlarged, and the heat dissipation performance of the heat dissipation plate 20 can be improved.

[0091] Fifteenth embodiment The fifteenth embodiment will be described. The fifteenth embodiment is different from the first embodiment in that a part of the configuration of the heat sink 20 is changed, and other parts are similar to the first embodiment, so only the parts that are different from the first embodiment will be described.

[0092] 22, in the fifteenth embodiment, the heat sink 20 has metal plates 50 on one side and the other side facing in 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 side. The metal plates 50 are formed of a material with low electrical resistivity, such as copper.

[0093] The semiconductor element 10 is bonded to a metal plate 50 provided on the element mounting side of the heat sink 20 by a bonding material 11. The bonding material 11 is, for example, solder.

[0094] In the semiconductor module 1 of the fifteenth embodiment described above, by providing a metal plate 50 on the element mounting side of the heat sink 20, the metal plate 50 can be used as wiring for passing electricity through the semiconductor element 10, thereby improving the functionality of the semiconductor module 1.

[0095] Furthermore, by providing metal plates 50 on the element mounting side and the cooling side of the heat sink 20, respectively, heat can be spread further in the direction perpendicular to the thickness direction of the heat sink 20, i.e., in the in-plane direction of the XY plane, in the first heat sink section 21 and the third heat sink section 23 via the metal plates 50. Therefore, heat can be spread over almost the entire area of ​​the heat sink 20, improving the heat dissipation performance of the heat sink 20.

[0096] 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.

[0097] First, the configuration of the semiconductor module of the third comparative example used for comparison will be described. As shown in FIG. 25, 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 in the fifteenth embodiment. The heat sink 20 has one heat sink 48 made of graphite 2, and metal plates 50 provided on the element mounting side and the cooling side of the heat sink 48. The one 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 made of copper, as in the fifteenth embodiment.

[0098] Steady-state thermal analysis was performed on the semiconductor module 1 described in the fifteenth embodiment and the semiconductor module 103 of the third comparative example. This steady-state thermal analysis was performed under the condition that the heat generation amount of the semiconductor element 10 was constant and cooling water at a temperature of 30°C was flowed through the cooler 30 provided on the cooling surface side of the heat sink 20. The size of the heat sink 20 was 40 mm in the X direction and 20 mm in the Y direction. The size of the semiconductor element 10 was 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 6.5 mm, and the size of each of the second heat sinks 22R and 22L in the X direction was 5 mm.

[0099] The results of analyzing the semiconductor module 1 of the fifteenth embodiment are shown in FIGS. 23 and 24, and the results of analyzing the semiconductor module 103 of the third comparative example are shown in FIGS. 26 and 27.

[0100] As a result of the analysis, the temperature of the heat sink 20 included in the semiconductor module 1 of the fifteenth embodiment is approximately uniform over the entire area of ​​the heat sink 20, compared to the temperature of the heat sink 20 included in the semiconductor module 103 of the third comparative example. From this, it can be said that the heat sink 20 included in the semiconductor module 1 of the fifteenth embodiment can dissipate heat using the entire area of ​​the heat sink 20, compared to the heat sink 20 included in the semiconductor module 103 of the third comparative example.

[0101] In contrast, the heat sink 20 of the semiconductor module 103 of the third comparative example has a lower temperature at one side and the other side in the Y direction compared to the heat sink 20 of the semiconductor module 1 of the fifteenth embodiment. For this reason, the heat sink 20 of the semiconductor module 103 of the third comparative example has parts to which heat is less easily transferred, i.e., wasted parts, compared to the heat sink 20 of the semiconductor module 1 of the fifteenth embodiment.

[0102] Regarding the temperature of the semiconductor element 10, the maximum temperature of the semiconductor element 10 included in the semiconductor module 103 of the third comparative example was 150° C., whereas the maximum temperature of the semiconductor element 10 included in the semiconductor module 1 of the fifteenth embodiment was 127° C. Therefore, it was found that the semiconductor module 1 of the fifteenth embodiment can lower the temperature of the semiconductor element 10 by dissipating heat using the entire area of ​​the heat sink 20, compared to the semiconductor module 103 of the third comparative example.

[0103] Sixteenth embodiment The sixteenth embodiment will be described. The sixteenth embodiment is a modified example of the fifteenth embodiment. In the fifteenth embodiment, metal plates 50 are provided on the element mounting side and the cooling side of the heat sink 20, respectively. In contrast, the sixteenth embodiment is configured to provide insulators 51 on the element mounting side and the cooling side of the heat sink 20, respectively. The insulators 51 are, for example, ceramic. It is preferable that the ceramic has a high thermal conductivity.

[0104] This makes it possible to electrically insulate the semiconductor module 1 from the outside. Also, in the first heat dissipation section 21 and the third heat dissipation section 23, the heat is spread further in a direction perpendicular to the thickness direction of the heat dissipation plate 20, i.e., 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.

[0105] As another modified example of the fifteenth and sixteenth embodiments, although not shown in the drawings, 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. In this way, 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 electrically insulate the semiconductor module 1 from the outside.

[0106] Moreover, the metal plate 50 and the insulator 51 are not limited to being provided on the entire surface of the heat sink 20 facing in the thickness direction, but may be provided on only a part of it.

[0107] Seventeenth embodiment The seventeenth embodiment will be described below. In the seventeenth embodiment, a part of the configuration of the heat sink 20 is changed from the fifteenth and sixteenth embodiments.

[0108] As shown in Fig. 29, in the seventeenth 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. Note that the ceramic has preferably high thermal conductivity. Similarly to the fifteenth embodiment, the heat sink 20 has metal plates 50 on both the element mounting side and the cooling side. The metal plates 50 are formed of a material with low electrical resistivity, such as copper.

[0109] The semiconductor module 1 of the seventeenth embodiment described above has a plate-shaped insulator 52 at the middle position in the thickness direction of the heat sink 20, thereby electrically insulating the semiconductor module 1 from the outside. Also, the metal plate 50 provided on the element mounting side of the heat sink 20 can be used as wiring. Furthermore, in the first heat sink section 21 and the third heat sink section 23, the heat is spread further in a direction perpendicular to the thickness direction of the heat sink 20, i.e., in the in-plane direction of the XY plane, via the metal plate 50 and the insulator 52, thereby improving the heat dissipation performance of the heat sink 20.

[0110] As a modification of the seventeenth embodiment, a metal plate 50 may be provided in place of or together with the insulator 52 at the intermediate position in the thickness direction of the heat sink 20.

[0111] As another modification of the seventeenth embodiment, an insulator 51 may be provided instead of the metal plate 50 on at least one of the element mounting surface and the cooling surface of the heat sink 20.

[0112] (18th embodiment) The eighteenth embodiment will be described below. In the eighteenth embodiment, a part of the configuration of the heat sink 20 is changed from that of the first embodiment.

[0113] 30 and 31, in the eighteenth embodiment, the heat sink 20 has a metal plate 50 covering a surface facing the thickness direction and a surface facing a direction perpendicular to the thickness direction. In other words, a plurality of heat dissipation parts constituting the heat sink 20 are encapsulated by the metal plate 50. The metal plate 50 is made of a material with low electrical resistivity, such as copper.

[0114] The semiconductor element 10 is bonded to a metal plate 50 provided on the element mounting side of the heat sink 20 by a bonding material 11. The bonding material 11 is, for example, solder.

[0115] The semiconductor module 1 of the 18th embodiment described above can achieve the same effects as those of the semiconductor module 1 of the 15th embodiment. Furthermore, the semiconductor module 1 of the 18th embodiment can increase the rigidity of the heat sink 20 by using the metal plate 50 that encapsulates the multiple heat sinks.

[0116] 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 .

[0117] Nineteenth embodiment The 19th embodiment will be described below. In the 19th embodiment, a part of the configuration of the heat sink 20 is changed from that of the first embodiment.

[0118] 32, in the nineteenth embodiment, the heat sink 20 has a plating layer 53 covering a surface facing the thickness direction and a surface facing a direction perpendicular to the thickness direction. In other words, a plurality of heat dissipation parts constituting the heat sink 20 are covered with the plating layer 53.

[0119] The semiconductor element 10 is bonded to the plating layer 53 provided on the element mounting side of the heat sink 20 by a bonding material 11. The bonding material 11 is, for example, solder.

[0120] The semiconductor module 1 of the nineteenth embodiment described above can achieve the same effects as those of the semiconductor module 1 of the eighteenth embodiment.

[0121] As a modification of the nineteenth embodiment, the plating layer 53 covering the heat sink 20 may partially cover a part of the heat sink 20 .

[0122] (Twentieth embodiment) The twentieth embodiment will be described. The twentieth embodiment is different from the first embodiment in that a part of the configuration of the heat sink 20 is changed, and other parts are similar to the first embodiment, so only the parts that are different from the first embodiment will be described.

[0123] As shown in Fig. 33 and Fig. 34, in the twentieth embodiment, the heat sink 20 has a first heat dissipation section 21 and a second heat dissipation section 22. The first heat dissipation section 21 and the second heat dissipation section 22 are the same as those described in the first embodiment. In Fig. 34, for the sake of explanation, the boundary between the portion of the first heat dissipation section 21 in the X direction with respect to the position immediately below the semiconductor element 10 and the portion of the first heat dissipation section 21 extending in a direction perpendicular to the in-plane direction of the first imaginary plane with respect to the position immediately below the semiconductor element 10 is shown by two-dot chain lines D1 to D4. The second heat dissipation section 22 is connected to the portion of the first heat dissipation section 21 in the X direction with respect to the position immediately below the semiconductor element 10, and is also connected in the X direction to the portion of the first heat dissipation section extending in a direction perpendicular to the in-plane direction of the first imaginary plane with respect to the position immediately below the semiconductor element 10.

[0124] In FIG. 34, a part of the path along which heat generated from the semiconductor element 10 is transmitted through the heat sink 20 is shown diagrammatically by arrows.

[0125] The heat generated from the semiconductor element 10 is transferred to a position of the first heat dissipation section 21 directly below the semiconductor element 10, and then transferred from that position to the second heat dissipation section 22 in the X direction, as shown by arrow T13 in Fig. 34. The heat then spreads along the XY plane in the second heat dissipation section 22. Note that, although the arrows are omitted, a portion of the heat transferred from the semiconductor element 10 to the position of the first heat dissipation section 21 directly below the semiconductor element 10 spreads along the XZ plane at the position of the first heat dissipation section 21 directly below the semiconductor element 10, and is dissipated from the cooling surface of the first heat dissipation section 21.

[0126] As indicated by arrow T14, the heat spread along the XY plane in second heat dissipation section 22 is conducted to a portion of first heat dissipation section 21 extending in the Y direction relative to a position directly below semiconductor element 10. Then, the heat spreads along the XZ plane in the portion of first heat dissipation section 21 extending in the Y direction relative to a position directly below semiconductor element 10, and is dissipated from the cooling surface of first heat dissipation section 21.

[0127] In this way, also in the semiconductor module 1 of the twentieth embodiment, by using the second heat dissipation section 22 as a heat redirection section, it is possible to spread the heat generated by the semiconductor element 10 over substantially the entire area of ​​the heat sink 20 and dissipate the heat from the cooling surface of the heat sink 20. Therefore, in this semiconductor module 1, the area in which the heat sink 20 functions as a heat dissipation surface can be expanded, and the heat dissipation performance of the heat sink 20 can be improved.

[0128] In the twentieth embodiment, the second heat dissipation portions 22R and 22L are disposed on one side and the other side in the X direction of the first heat dissipation portion 21. In contrast, as a modification of the twentieth embodiment, the second heat dissipation portion 22 may be disposed only on one side or the other side in the X direction of the first heat dissipation portion 21.

[0129] (Other embodiments) (1) In each of the above embodiments, the heat sink 20 of the semiconductor module 1 has a plurality of heat dissipation parts arranged in a straight line, but this is not limited thereto. For example, the plurality of heat dissipation parts may be arranged in a bent shape, such as an L-shape or a U-shape.

[0130] (2) In each of the above embodiments, the third imaginary plane that defines the direction in which the third heat dissipation section 23 has high thermal conductivity is parallel to the direction in which the third heat dissipation section 23 is connected to the second heat dissipation section 22 and parallel to the thickness direction, but is not limited to this. For example, the third imaginary plane may be at any angle other than perpendicular to the direction in which the third heat dissipation section 23 is connected to the second heat dissipation section 22.

[0131] (3) In each of the above embodiments, the first imaginary plane that defines the direction in which the first heat dissipation section 21 has high thermal conductivity and the third imaginary plane that defines the direction in which the third heat dissipation section 23 has high thermal conductivity are parallel to each other, but this is not limited to the above. For example, the first imaginary plane and the third imaginary plane may form any angle.

[0132] The present disclosure is not limited to the above-mentioned embodiments, and can be appropriately modified within the scope of the claims. In addition, the above-mentioned embodiments and parts thereof are not unrelated to each other, and can be appropriately combined except when the combination is clearly impossible. In addition, in each of the above-mentioned embodiments, it goes without saying that the elements constituting the embodiment are not necessarily essential, except when it is specifically stated that they are essential or when it is clearly considered to be essential in principle. In addition, in each of the above-mentioned embodiments, when the numbers, values, amounts, ranges, etc. of the components of the embodiment are mentioned, they are not limited to the specific numbers, except when it is specifically stated that they are essential or when it is clearly limited to a specific number in principle. In addition, in each of the above-mentioned embodiments, when the shape, positional relationship, etc. of the components are mentioned, they are not limited to the shape, positional relationship, etc., except when it is specifically stated that they are essential or when it is clearly limited to a specific shape, positional relationship, etc. in principle.

[0133] (In view of the present disclosure) The present disclosure described above can be understood from the following viewpoints, for example. [First viewpoint] A semiconductor module including a plate-shaped heat sink (20) and a semiconductor element (10) disposed in the thickness direction of the heat sink and generating heat when current is applied thereto, the heat dissipation plate has a first heat dissipation portion (21), a second heat dissipation portion (22), and a third heat dissipation portion (23) formed by including a material having anisotropic thermal conductivity; the first heat dissipation portion is provided including a position facing the semiconductor element in the thickness direction, and has high thermal conductivity in an in-plane direction of an arbitrary first imaginary plane parallel to the thickness direction; the second heat dissipation portion is connected to the first heat dissipation portion in a direction parallel to an in-plane direction of the first imaginary plane and perpendicular to the thickness direction, and has high thermal conductivity in the in-plane direction of the second imaginary plane perpendicular to the thickness direction. [Second viewpoint] A semiconductor module described in a first aspect, wherein the second heat dissipation portion is connected to a portion of the first heat dissipation portion that is parallel to the in-plane direction of the first imaginary plane and perpendicular to a thickness direction of the heat dissipation plate relative to a position facing 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 imaginary plane relative to a position facing the semiconductor element. [Third Perspective] The heat dissipation plate further includes a third heat dissipation portion (23), The semiconductor module according to the first or second aspect, wherein the third heat dissipation portion is connected to the second heat dissipation portion in any direction parallel to the in-plane direction of the second imaginary plane, and has high thermal conductivity in an in-plane direction of the third imaginary plane that is not perpendicular to the direction in which the third heat dissipation portion is connected to the second heat dissipation portion and is parallel to the thickness direction. [Fourth viewpoint] The semiconductor module according to a third aspect, wherein the third imaginary 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. [Fifth viewpoint] The semiconductor module according to the third or fourth aspect, wherein the first imaginary plane and the third imaginary 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. [Sixth viewpoint] The semiconductor module according to any one of the first to fifth aspects, further comprising a metal plate (50) provided on a surface of the heat sink facing the thickness direction or at a middle position of the heat sink in the thickness direction. [Seventh viewpoint] The semiconductor module according to any one of the first to sixth aspects, further comprising a plate-shaped insulator (51, 52) provided on a surface of the heat sink facing the thickness direction or at a central position of the heat sink in the thickness direction. [Eighth viewpoint] The semiconductor module according to any one of the first to seventh aspects, further comprising a metal plate covering a surface of the heat sink facing the thickness direction and a surface facing a direction perpendicular to the thickness direction. [Ninth viewpoint] The semiconductor module according to any one of the first to eighth aspects, further comprising a metal plating layer (53) provided on a surface of the heat sink facing the thickness direction. [10th viewpoint] A plate-shaped heat sink that dissipates heat generated by a semiconductor element (10) used in a semiconductor module, the semiconductor element is provided in a thickness direction of the heat sink, The heat dissipation plate has a first heat dissipation portion (21) and a second heat dissipation portion (22) formed by including a material having anisotropic thermal conductivity, the first heat dissipation portion is provided including a position facing the semiconductor element in the thickness direction, and has high thermal conductivity in an in-plane direction of an arbitrary first imaginary plane parallel to the thickness direction; 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 imaginary plane and perpendicular to the thickness direction, and has high thermal conductivity in the in-plane direction of the second imaginary plane perpendicular to the thickness direction. The tenth aspect can be arbitrarily combined with the second to ninth aspects. [Explanation of symbols]

[0134] 1 Semiconductor module 10 Semiconductor elements 20 Heat sink 21 1st heat dissipation section 22 Second heat dissipation section

Claims

1. A semiconductor module including a plate-shaped heat sink (20) and a semiconductor element (10) disposed in the thickness direction of the heat sink and generating heat when current is applied thereto, The heat sink has a first heat dissipation portion (21) and a second heat dissipation portion (22) formed by including a material having anisotropic thermal conductivity, the first heat dissipation portion is provided including a position facing the semiconductor element in the thickness direction, and has high thermal conductivity in an in-plane direction of an arbitrary first imaginary plane parallel to the thickness direction; the second heat dissipation portion is connected to the first heat dissipation portion in a direction parallel to an in-plane direction of the first imaginary plane and perpendicular to the thickness direction, and has high thermal conductivity in the in-plane direction of the second imaginary plane perpendicular to the thickness direction.

2. 2. The semiconductor module according to claim 1, wherein the second heat dissipation portion is connected to a portion of the first heat dissipation portion that is parallel to an in-plane direction of the first imaginary plane and perpendicular to a thickness direction of the heat dissipation plate with respect to a position facing 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 imaginary plane with respect to a position facing the semiconductor element.

3. The heat sink further has a third heat sink portion (23), 3. The semiconductor module according to claim 1, wherein the third heat dissipation portion is connected to the second heat dissipation portion in any direction parallel to an in-plane direction of the second imaginary plane, and has high thermal conductivity in an in-plane direction of the third imaginary plane that is not perpendicular 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.

4. The semiconductor module according to claim 3 , wherein the third imaginary 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 , wherein the first imaginary plane and the third imaginary 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. 3. The semiconductor module according to claim 1, wherein the heat sink further comprises a metal plate (50) provided on a surface facing the thickness direction or at a middle position of the heat sink in the thickness direction.

7. 3. The semiconductor module according to claim 1, wherein the heat sink further comprises a plate-shaped insulator (51, 52) provided on a surface facing the thickness direction or at a middle position of the heat sink in the thickness direction.

8. The semiconductor module according to claim 1 , wherein the heat sink further comprises a metal plate covering a surface facing the thickness direction and a surface facing a direction perpendicular to the thickness direction.

9. 3. The semiconductor module according to claim 1, wherein the heat sink further comprises a metal plating layer (53) provided on a surface facing the thickness direction.

10. A plate-shaped heat sink that dissipates heat generated by a semiconductor element (10) used in a semiconductor module, the semiconductor element is provided in a thickness direction of the heat sink, The heat sink has a first heat dissipation portion (21) and a second heat dissipation portion (22) formed by including a material having anisotropic thermal conductivity, the first heat dissipation portion is provided including a position facing the semiconductor element in the thickness direction, and has high thermal conductivity in an in-plane direction of an arbitrary first imaginary plane parallel to the thickness direction; 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 imaginary plane and perpendicular to the thickness direction, and has high thermal conductivity in the in-plane direction of the second imaginary plane perpendicular to the thickness direction.

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