Semiconductor module

Abstract

This design ensures sufficient creepage distance between the connection terminals and the heat dissipation surface while preventing a shortage of thermal conductive material installed on the heat dissipation surface. [Solution] The semiconductor module comprises a housing including a first main surface and a second main surface facing opposite directions from each other, and a side surface between the first main surface and the second main surface; a mounting substrate housed in the housing; a semiconductor chip mounted on the mounting substrate; and connection terminals protruding from the side surface. The second main surface includes a base surface with an opening formed therein and a first stepped surface located between the base surface and the side surface in a plan view, recessed toward the first main surface relative to the base surface. The mounting substrate includes a heat dissipation surface located inside the opening, and a first groove is formed on the first stepped surface along the side surface.

Description

[Technical Field]

[0001] The present disclosure relates to a semiconductor module. [Background Art]

[0002] Semiconductor modules having a structure in which a plurality of connection terminals protrude from a housing have been conventionally proposed (Patent Documents 1 to 5). For example, Patent Document 1 discloses a configuration in which a creepage distance between adjacent lead terminals is secured by forming a groove in a region between mutually adjacent lead terminals on a lower surface of a semiconductor package. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2022-131370 [Patent Document 2] International Publication No. WO 2023 / 210379 [Patent Document 3] Japanese Patent No. 6752381 [Patent Document 4] Japanese Unexamined Patent Publication No. 2007-73743 [Patent Document 5] International Publication No. WO 2017 / 175612 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] The bottom surface of a semiconductor module is used as a heat dissipation surface. For example, a configuration is assumed in which the heat dissipation surface of the semiconductor module faces a cooler (e.g., a heat sink) via a heat conductive material such as heat conductive grease. However, in a configuration in which a groove for securing a creepage distance is formed on the bottom surface of the semiconductor module, the heat conductive material enters the groove, and as a result, there is a possibility that the heat conductive material interposed between the semiconductor module and the cooler becomes insufficient. In consideration of the above circumstances, an object of one aspect of the present disclosure is to secure a creepage distance between the connection terminal and the heat dissipation surface while suppressing a shortage of the heat conductive material disposed on the heat dissipation surface. [Means for solving the problem]

[0005] A semiconductor module according to one aspect of the present disclosure comprises a housing including a first main surface and a second main surface facing opposite directions from each other, and a side surface between the first main surface and the second main surface; a mounting substrate housed in the housing; a semiconductor chip mounted on the mounting substrate; and connection terminals protruding from the side surface, wherein the second main surface includes a base surface with an opening formed thereon and a first stepped surface located between the base surface and the side surface in a plan view and recessed toward the first main surface relative to the base surface; the mounting substrate includes a heat dissipation surface located inside the opening; and the first stepped surface has a first groove recessed toward the first main surface and along the extending direction of the side surface.

[0006] A semiconductor module according to another aspect of the present disclosure comprises a housing including a first main surface and a second main surface facing opposite directions from each other, a first side surface and a third side surface facing opposite directions between the first main surface and the second main surface, a mounting substrate housed in the housing, a semiconductor chip mounted on the mounting substrate, a first connection terminal protruding from the first side surface, and a second connection terminal protruding from the third side surface, wherein the second main surface has a base surface with an opening formed therein, and in plan view, the base surface and the first The mounting substrate includes a first stepped surface located between the base surface and the side surface and recessed toward the first main surface with respect to the base surface, and a second stepped surface located between the base surface and the third side surface in a plan view and recessed toward the first main surface with respect to the base surface, the mounting substrate includes a heat dissipation surface located inside the opening, the first stepped surface has a first groove recessed toward the first main surface and along the extending direction of the first side surface, and the second stepped surface has a second groove recessed toward the first main surface and along the extending direction of the third side surface. [Brief explanation of the drawing]

[0007] [Figure 1] This is a cross-sectional view of a semiconductor module according to the first embodiment. [Figure 2] This is a plan view of a semiconductor module as seen from the -Z direction. [Figure 3]This is an enlarged cross-sectional view of the vicinity of the second principal surface in a semiconductor module. [Figure 4] This is a plan view of the semiconductor module of the second embodiment as seen from the -Z direction. [Figure 5] This is a cross-sectional view of the vicinity of the second main surface in the semiconductor module of the second embodiment. [Figure 6] This is a cross-sectional view of the vicinity of the second main surface in the semiconductor module of the third embodiment. [Figure 7] This is a cross-sectional view of the vicinity of the second main surface in the semiconductor module of the fourth embodiment. [Figure 8] This is a cross-sectional view of the vicinity of the second main surface in the semiconductor module of the fifth embodiment. [Figure 9] This is a plan view of the semiconductor module of the sixth embodiment as seen from the -Z direction. [Figure 10] This is a plan view of the semiconductor module of the seventh embodiment, viewed from the -Z direction. [Figure 11] This is a cross-sectional view of the vicinity of the second principal surface in a modified semiconductor module. [Figure 12] This is a cross-sectional view of the vicinity of the second principal surface in a modified semiconductor module. [Figure 13] This is a plan view of a modified semiconductor module as seen from the -Z direction. [Figure 14] This is a plan view of a modified semiconductor module as seen from the -Z direction. [Modes for carrying out the invention]

[0008] The embodiments for implementing this disclosure will be described with reference to the drawings. Note that the dimensions and scale of the elements in each drawing may differ from those of the actual product. Furthermore, the embodiments described below are illustrative examples of embodiments that may be envisioned when implementing this disclosure. Therefore, the scope of this disclosure is not limited to the embodiments exemplified below.

[0009] 1. First Embodiment FIG. 1 is a cross-sectional view of a semiconductor module 100 according to a first embodiment of the present disclosure. The semiconductor module 100 of the first embodiment is a power semiconductor module used for example in a power conversion device such as an inverter circuit.

[0010] In the following description, three mutually orthogonal axes (X-axis, Y-axis, Z-axis) are assumed. A direction along the X-axis (+X direction and -X direction) is referred to as "X direction". Similarly, a direction along the Y-axis (+Y direction and -Y direction) is referred to as "Y direction", and a direction along the Z-axis (+Z direction and -Z direction) is referred to as "Z direction".

[0011] In an actual usage state, the semiconductor module 100 may be installed in any direction, but for convenience in the following description, the +Z direction is assumed to be upward and the -Z direction is assumed to be downward. Accordingly, a surface of any element of the semiconductor module 100 facing the +Z direction may be referred to as an "upper surface", and a surface of the element facing the -Z direction may be referred to as a "lower surface". In the following description, observing any element of the semiconductor module 100 along a line of sight along the Z direction is referred to as "planar view". It should be noted that the directions of the three orthogonal axes (X direction, Y direction, Z direction) are independent of the direction of gravity.

[0012] FIG. 2 is a plan view of the semiconductor module 100 viewed from the -Z direction. That is, FIG. 2 illustrates the lower surface of the semiconductor module 100. As illustrated in FIGS. 1 and 2, the semiconductor module 100 of the first embodiment includes a housing 10 and a semiconductor unit 20.

[0013] The container 10 is a structure that accommodates the semiconductor unit 20. The container 10 is formed of, for example, a thermoplastic resin or a thermosetting resin. Examples of the thermoplastic resin include PPS (polyphenylene sulfide) resin, PBT (polybutylene terephthalate) resin, PBS (polybutylene succinate) resin, PA (polyamide) resin, and ABS (acrylonitrile-butadiene-styrene) resin. An example of the thermosetting resin is epoxy resin. For example, the container 10 and the semiconductor unit 20 are integrally formed by transfer molding in which a liquid resin material is filled into a mold on which the semiconductor unit 20 is placed. As described above, the semiconductor module 100 according to the first embodiment is a full-mold semiconductor package.

[0014] The container 10 is formed in a flat, substantially rectangular parallelepiped shape including a first main surface 11 and a second main surface 12 facing opposite to each other, and a side surface 13 between the first main surface 11 and the second main surface 12. The first main surface 11 is a substantially rectangular upper surface (top surface) of the container 10 facing the +Z direction. The second main surface 12 is a substantially rectangular lower surface (bottom surface) of the container 10 facing the -Z direction. The Z direction is a direction from one of the first main surface 11 and the second main surface 12 toward the other, and corresponds to the thickness direction (height direction) of the container 10.

[0015] The side surface 13 is an outer wall surface that connects the first main surface 11 and the second main surface 12. Specifically, the side surface 13 includes a side surface 13a, a side surface 13b, a side surface 13c, and a side surface 13d. The side surface 13a and the side surface 13b are outer wall surfaces facing opposite to each other between the first main surface 11 and the second main surface 12. Specifically, the side surface 13a is a region of the side surface 13 of the container 10 facing the -X direction. The side surface 13b is a region of the side surface 13 of the container 10 facing the +X direction. That is, the Y direction is expressed as the direction in which the side surface 13a or the side surface 13b extends in plan view (hereinafter referred to as the "extending direction").

[0016] Sides 13c and 13d are outer wall surfaces facing opposite directions between the first main surface 11 and the second main surface 12. Specifically, side 13c is the region of side 13 of the housing 10 that faces the +Y direction. Side 13d is the surface of side 13 of the housing 10 that faces the -Y direction. In other words, side 13a and side 13b intersect with side 13c and side 13d in a plan view.

[0017] As illustrated in Figure 1, the semiconductor unit 20 includes a mounting substrate 21, a semiconductor chip 22, connection leads 23, control leads 24, and a control chip 25. The mounting substrate 21 is a wiring board on which the semiconductor chip 22 is mounted. For example, a DCB (Direct Copper Bonding) substrate, an AMB (Active Metal Brazing) substrate, or an IMS (Insulated Metal Substrate) substrate can be used as the mounting substrate 21. The mounting substrate 21 is housed in the housing 10.

[0018] The mounting substrate 21 is constructed by laminating an insulating substrate 211, a heat sink 212, and a conductive pattern 213. The insulating substrate 211 is a rectangular plate-shaped member made of an insulating material. The insulating substrate 211 is made of a ceramic material such as aluminum oxide, aluminum nitride, or silicon nitride, or a resin material such as epoxy resin.

[0019] The heat sink 212 is a plate-shaped member bonded to the surface of the insulating substrate 211 facing the -Z direction (i.e., the bottom surface). The heat sink 212 is made of a highly thermally conductive metal material such as copper or aluminum. The surface of the heat sink 212 facing the -Z direction (hereinafter referred to as the "heat dissipation surface F") faces the surface C of the cooler 90. The cooler 90 is a heat dissipation member such as a heat sink.

[0020] A thermal conductive material 91 is placed between the heat dissipation surface F of the mounting substrate 21 and the surface C of the cooler 90. The thermal conductive material 91 is a fluid thermal conductive material such as thermal conductive grease. Heat propagated from the semiconductor chip 22 to the insulating substrate 211 is propagated from the heat dissipation surface F to the cooler 90 via the thermal conductive material 91. In other words, the heat dissipation surface F is the surface for heat dissipation of the semiconductor module 100. The heat sink 212 may also be used as a grounding element set to ground potential.

[0021] The conductive pattern 213 is a thin film or thin plate-like conductor placed on the surface of the insulating substrate 211 facing the +Z direction (i.e., the top surface). For example, the conductive pattern 213 is formed from a low-resistance conductive material such as copper or a copper alloy.

[0022] The semiconductor chip 22 is a power semiconductor element installed on the mounting substrate 21 and is used as a switching element to switch between conducting and interrupting current. The semiconductor chip 22 in the first embodiment is, for example, an RC-IGBT (Reverse Conducting IGBT) including an IGBT (Insulated Gate Bipolar Transistor) and an FWD (Free Wheeling Diode). The semiconductor chip 22 is bonded to the conductive pattern 213 by a conductive bonding material (not shown), such as solder or sintered material. The semiconductor chip 22 is housed in the housing 10. In reality, multiple semiconductor chips 22 are installed on the mounting substrate 21, but only one semiconductor chip 22 is shown in Figure 2 for convenience.

[0023] The connecting leads 23 are lead frames electrically connected to the semiconductor chip 22. As illustrated in Figure 2, the semiconductor module 100 comprises a plurality of interconnecting leads 23 spaced apart from each other. Each connecting lead 23 is exposed to the outside space by penetrating the side surface 13a from the inside of the housing 10. The portion of each connecting lead 23 located inside the housing 10 is electrically connected to the main electrode (e.g., collector electrode or emitter electrode) of the semiconductor chip 22.

[0024] The portion of each connection lead 23 that is exposed to the external space (hereinafter referred to as "connection terminal 27a") protrudes from the side surface 13a of the housing 10 in the -X direction. That is, on the side surface 13a of the housing 10, multiple connection terminals 27a protruding outward (in the -X direction) from the side surface 13a are arranged at intervals from each other in the Y direction. Each connection terminal 27a is a conductor for electrically connecting the semiconductor unit 20 to an external device such as a power supply or load device. Specifically, the multiple connection terminals 27a include a power supply terminal (P terminal) for the high-level power supply voltage, a power supply terminal (N terminal) for the low-level power supply voltage, and output terminals (U terminal, V terminal, W terminal) for supplying power to a load device such as an electric motor.

[0025] The control leads 24 are lead frames used to control the semiconductor module 100. As illustrated in Figure 2, the semiconductor module 100 comprises a plurality of control leads 24 spaced apart from each other. Each control lead 24 penetrates the side surface 13b from the inside of the housing 10 and is exposed to the outside space. A control chip 25 is mounted on the portion of each control lead 24 that is located inside the housing 10. The control chip 25 is housed in the housing 10.

[0026] The control chip 25 is a drive circuit that controls the semiconductor chip 22. The control chip 25 is electrically connected to the semiconductor chip 22, for example, by a wire 26. As described above, the semiconductor module 100 of the first embodiment is an intelligent power module (IPM) with a built-in control chip 25. However, the control chip 25 may be omitted from the semiconductor module 100.

[0027] The portion of each control lead 24 that is exposed to the external space (hereinafter referred to as "connection terminal 27b") protrudes from the side surface 13b of the housing 10 in the +X direction. That is, on the side surface 13b of the housing 10, multiple connection terminals 27b protruding outward (in the +X direction) from the side surface 13b are arranged at intervals from each other in the Y direction. Each connection terminal 27b is a conductor for electrically connecting the semiconductor unit 20 to an external device.

[0028] Figure 3 is an enlarged cross-sectional view of the vicinity of the second main surface 12 in the housing 10. As illustrated in Figures 2 and 3, the second main surface 12 of the housing 10 includes a base surface 31, a stepped surface 32a1, a connecting surface 33a1, a stepped surface 32b1, and a connecting surface 33b1. In a plan view, the base surface 31 is located between the stepped surface 32a1 and the stepped surface 32b1.

[0029] The base surface 31 is a horizontal, flat surface of the second main surface 12 that aligns with the XY plane. An opening 311 is formed in the base surface 31. The mounting substrate 21 is placed inside the opening 311 in a plan view. That is, the inner wall surface of the opening 311 in the housing 10 and the outer wall surface of the mounting substrate 21 are in close contact with each other. Therefore, the heat dissipation surface F of the mounting substrate 21 is exposed inside the opening 311. In other words, the base surface 31 is a frame-shaped plane that surrounds the heat dissipation surface F all the way around. As illustrated in Figure 1, the base surface 31 of the housing 10 and the heat dissipation surface F of the mounting substrate 21 are located in the same plane, and the heat dissipation surface F of the mounting substrate 21 is exposed from the base surface 31.

[0030] As illustrated in Figure 2, the stepped surface 32a1 is the region of the second main surface 12 located between the base surface 31 and the side surface 13a in a plan view. The stepped surface 32a1 is a horizontal flat surface of the second main surface 12 that aligns with the XY plane and extends in the Y direction along the entire length of the housing 10 in the Y direction. As illustrated in Figures 1 and 3, the stepped surface 32a1 is a surface that is recessed toward the first main surface 11 side (+Z direction) relative to the base surface 31. That is, the stepped surface 32a1 is located between the first main surface 11 and the second main surface 12 in the Z direction. In other words, the stepped surface 32a1 is located closer to the first main surface 11 than to the base surface 31 in the Z direction. Therefore, as illustrated in Figure 1, the stepped surface 32a1 faces the surface C of the cooler 90 with a gap between them.

[0031] The connecting surface 33a1 is a wall surface that connects the base surface 31 and the stepped surface 32a1. That is, the connecting surface 33a1 intersects with both the base surface 31 and the stepped surface 32a1. As illustrated in Figure 3, the height difference Sa1 between the base surface 31 and the stepped surface 32a1 corresponds to the height of the connecting surface 33a1. The height difference Sa1 is, for example, 1 mm or more. Therefore, a gap of 1 mm or more is ensured between the stepped surface 32a1 and the surface C of the cooler 90. However, the value of the height difference Sa1 is not limited to a value within the above range and may be changed arbitrarily.

[0032] A groove 34a1 is formed in the stepped surface 32a1. The groove 34a1 is a recess that is recessed toward the first main surface 11 relative to the stepped surface 32a1. Specifically, as illustrated in Figure 2, the groove 34a1 extends linearly along the extending direction (Y direction) of the side surface 13a in a plan view. In the first embodiment, the groove 34a1 extends in the Y direction along the entire length of the housing 10 (or stepped surface 32a1) in the Y direction. The groove 34a1 is formed at a position spaced apart from the connecting surface 33a1 in the -X direction.

[0033] As illustrated in Figure 3, the cross-sectional shape of the groove 34a1 is rectangular (for example, rectangular or trapezoidal). The depth Da1 of the groove 34a1 is less than the distance Ha between the lower surface of the connection terminal 27a and the stepped surface 32a1. The depth Da1 is the distance between the bottom surface of the groove 34a1 and the stepped surface 32a1. The depth Da1 of the groove 34a1 is, for example, less than half of the distance Ha between the lower surface of the connection terminal 27a and the stepped surface 32a1. The depth Da1 of the groove 34a1 is equivalent to the height difference Sa1 between the base surface 31 and the stepped surface 32a1. The width Wa1 of the groove 34a1 is, for example, 0.5 mm or more. The width Wa1 is the dimension of the bottom surface of the groove 34a1 in the X direction.

[0034] As illustrated in Figure 2, the stepped surface 32b1 is the region of the second main surface 12 located between the base surface 31 and the side surface 13b in a plan view. The stepped surface 32b1 is a horizontal flat surface of the second main surface 12 that aligns with the XY plane and extends in the Y direction along the entire length of the housing 10 in the Y direction. As illustrated in Figures 1 and 3, the stepped surface 32b1 is a surface that is recessed toward the first main surface 11 side (+Z direction) relative to the base surface 31. That is, the stepped surface 32b1 is located between the first main surface 11 and the second main surface 12 in the Z direction. In other words, the stepped surface 32b1 is located closer to the first main surface 11 than to the base surface 31 in the Z direction. Therefore, as illustrated in Figure 1, the stepped surface 32b1 faces the surface C of the cooler 90 with a gap between them.

[0035] The connecting surface 33b1 is a wall surface that connects the base surface 31 and the stepped surface 32b1. That is, the connecting surface 33b1 intersects with both the base surface 31 and the stepped surface 32b1. As illustrated in Figure 3, the height difference Sb1 between the base surface 31 and the stepped surface 32b1 corresponds to the height of the connecting surface 33b1. The height difference Sb1 is, for example, 1 mm or more. Therefore, a gap of 1 mm or more is ensured between the stepped surface 32b1 and the surface C of the cooler 90. However, the value of the height difference Sb1 is not limited to a value within the above range and may be changed arbitrarily.

[0036] A groove 34b1 is formed in the stepped surface 32b1. The groove 34b1 is a recess that is recessed toward the first main surface 11 side relative to the stepped surface 32b1. Specifically, as illustrated in Figure 2, the groove 34b1 extends linearly in the extending direction (Y direction) of the side surface 13b in a plan view. In the first embodiment, the groove 34b1 extends in the Y direction along the entire length of the housing 10 (or stepped surface 32b1) in the Y direction. The groove 34b1 is formed at a position spaced apart from the connecting surface 33b1 in the +X direction.

[0037] As illustrated in Figure 3, the cross-sectional shape of the groove 34b1 is rectangular (for example, rectangular or trapezoidal). The depth Db1 of the groove 34b1 is less than the distance Hb between the lower surface of the connection terminal 27b and the stepped surface 32b1. The depth Db1 is the distance between the bottom surface of the groove 34b1 and the stepped surface 32b1. The depth Db1 of the groove 34b1 is equivalent to the height difference Sb1 between the base surface 31 and the stepped surface 32b1. The width Wb1 of the groove 34b1 is, for example, 0.5 mm or more. The width Wb1 is the dimension of the bottom surface of the groove 34b1 in the X direction.

[0038] As described above, in the first embodiment, a groove 34a1 is formed on the second main surface 12 (step surface 32a1) along the extension direction (Y direction) of the side surface 13a of the housing 10. Therefore, it is easy to secure a creepage distance between the connection terminal 27a and the heat dissipation surface F. Similarly, a groove 34b1 is formed on the second main surface 12 (step surface 32b1) along the extension direction (Y direction) of the side surface 13b of the housing 10. Therefore, it is easy to secure a creepage distance between the connection terminal 27b and the heat dissipation surface F. In other words, the height of the housing 10 (distance between the first main surface 11 and the base surface 31) required to secure a sufficient creepage distance between the connection terminal 27a or the connection terminal 27b and the heat dissipation surface F can be reduced. In particular, in the first embodiment, grooves 34a1 and grooves 34b1 are formed on the second main surface 12. Therefore, compared to a configuration in which only one of grooves 34a1 and groove 34b1 is formed, there is an advantage in that it is easier to secure creepage distance between both connection terminals 27a and 27b and the heat dissipation surface F.

[0039] Furthermore, in the first embodiment, a groove 34a1 is formed on a stepped surface 32a1 of the second main surface 12 of the housing 10 that is recessed toward the first main surface 11 relative to the base surface 31. Therefore, compared to a configuration in which the groove 34a1 is formed on the base surface 31, the possibility of the heat conductive material 91 entering the groove 34a1 can be reduced. Similarly, a groove 34b1 is formed on a stepped surface 32b1 of the second main surface 12 of the housing 10 that is recessed toward the first main surface 11 relative to the base surface 31. Therefore, compared to a configuration in which the groove 34b1 is formed on the base surface 31, the possibility of the heat conductive material 91 entering the groove 34b1 can be reduced. As a result of suppressing the entry of the heat conductive material 91 into the groove 34a1 or groove 34b1, the heat conductive material 91 spreads uniformly between the base surface 31 and the cooler 90. Therefore, a shortage of heat conductive material 91 between the base surface 31 and the cooler 90 can be suppressed.

[0040] Furthermore, it is preferable that the depth Da1 of the groove 34a1 is less than or equal to half the distance Ha between the lower surface of the connection terminal 27a and the stepped surface 32a1. If the depth Da1 of the groove 34a1 is greater than half the distance Ha, the connection terminal 27a and the bottom surface of the groove 34a1 become closer, and the mechanical strength of the housing 10 decreases. With a configuration in which the depth Da1 of the groove 34a1 is less than or equal to half the distance Ha, the mechanical strength of the housing 10 can be maintained.

[0041] In the first embodiment, the groove 34a1 is continuous along the extension direction of the side surface 13a over the entire length of the housing 10. Therefore, it is easy to secure a creepage distance between the multiple connection terminals 27a and the heat dissipation surface F over the entire length of the housing 10 in the Y direction. Similarly, since the groove 34b1 is continuous along the extension direction of the side surface 13b over the entire length of the housing 10, it is easy to secure a creepage distance between the multiple connection terminals 27b and the heat dissipation surface F over the entire length of the housing 10 in the Y direction.

[0042] Furthermore, in the first embodiment, the height difference Sa1 between the base surface 31 and the stepped surface 32a1 is 1 mm or more. That is, a gap of 1 mm or more is ensured between the stepped surface 32a1 and the surface C of the cooler 90. This ensures a creepage distance between the connection terminal 27a and the surface C of the cooler 90. Similarly, in the first embodiment, since the height difference Sb1 between the base surface 31 and the stepped surface 32b1 is 1 mm or more, a creepage distance between the connection terminal 27b and the surface C of the cooler 90 can be effectively ensured.

[0043] 2. Second Embodiment A second embodiment will now be described. For elements whose function is the same as in the first embodiment in each of the embodiments described below, the same reference numerals as in the first embodiment will be used, and detailed descriptions of each will be omitted as appropriate.

[0044] Figure 4 is a plan view of the semiconductor module 100 of the second embodiment as seen from the -Z direction. Figure 5 is an enlarged cross-sectional view of the vicinity of the second main surface 12 in the semiconductor module 100. The second main surface 12 of the second embodiment includes a base surface 31, a stepped surface 32a1, a connecting surface 33a1, a stepped surface 32b1, and a connecting surface 33b1, similar to the first embodiment.

[0045] As illustrated in Figures 4 and 5, in addition to the groove 34a1 similar to that in the first embodiment, a groove 34a2 parallel to groove 34a1 is formed on the stepped surface 32a1. That is, grooves 34a1 and 34a2 are adjacent to each other with a gap between them in the X direction. Groove 34a2 is a recess formed between the side surface 13a and groove 34a1 on the stepped surface 32a1 and recessed toward the first main surface 11. Like groove 34a1, groove 34a2 extends linearly along the extending direction (Y direction) of the side surface 13a. Specifically, groove 34a2 extends in the Y direction along the entire length of the housing 10 (or stepped surface 32a1) in the Y direction.

[0046] The cross-sectional shape of groove 34a2 is rectangular (e.g., rectangular or trapezoidal), similar to groove 34a1. The depth Da2 of groove 34a2 is the same as the depth Da1 of groove 34a1. Therefore, the depth Da2 is less than the distance Ha between the lower surface of the connection terminal 27a and the stepped surface 32a1. Also, the width Wa2 of groove 34a2 is the same as the width Wa1 of groove 34a1. That is, the width Wa2 of groove 34a2 is, for example, 0.5 mm or more.

[0047] The distance Ea1 between the connecting surface 33a1 and the groove 34a1 is, for example, 0.5 mm or more. Similarly, the distance Ea2 between the groove 34a1 and the groove 34a2 is, for example, 0.5 mm or more. Similarly, the distance Ea3 between the side surface 13a and the groove 34a2 is also, for example, 0.5 mm or more.

[0048] As illustrated in Figures 4 and 5, in addition to the groove 34b1 similar to that in the first embodiment, a groove 34b2 parallel to groove 34b1 is formed on the stepped surface 32b1. That is, grooves 34b1 and 34b2 are adjacent to each other with a gap in the X direction. Groove 34b2 is a recess formed between the side surface 13b and groove 34b1 on the stepped surface 32b1 and recessed toward the first main surface 11. Like groove 34b1, groove 34b2 extends linearly along the extension direction (Y direction) of the side surface 13b. Specifically, groove 34b2 extends in the Y direction along the entire length of the housing 10 (or stepped surface 32b1) in the Y direction.

[0049] The cross-sectional shape of groove 34b2 is rectangular (e.g., rectangular or trapezoidal), similar to groove 34b1. The depth Db2 of groove 34b2 is the same as the depth Db1 of groove 34b1. Therefore, the depth Db2 is less than the distance Hb between the lower surface of the connection terminal 27b and the stepped surface 32b1. Also, the width Wb2 of groove 34b2 is the same as the width Wb1 of groove 34b1. That is, the width Wb2 of groove 34b2 is, for example, 0.5 mm or more.

[0050] The distance Eb1 between the connecting surface 33b1 and the groove 34b1 is, for example, 0.5 mm or more. Similarly, the distance Eb2 between the groove 34b1 and the groove 34b2 is, for example, 0.5 mm or more. Similarly, the distance Eb3 between the side surface 13b and the groove 34b2 is also, for example, 0.5 mm or more.

[0051] In the second embodiment, the same effects as in the first embodiment are achieved. In the second embodiment, grooves 34a1 and 34a2 are formed on the stepped surface 32a1 of the housing 10. Therefore, compared to a configuration in which only groove 34a1 is formed on the stepped surface 32a1 (for example, the first embodiment), it is easier to secure the creepage distance between the connection terminal 27a and the heat dissipation surface F. Similarly, since grooves 34b1 and 34b2 are formed on the stepped surface 32b1 of the housing 10, it is easier to secure the creepage distance between the connection terminal 27b and the heat dissipation surface F. In addition, since the creepage distance between the connection terminals 27a and 27b and the heat dissipation surface F can be secured more reliably, the height of the housing 10 (distance between the first main surface 11 and the base surface 31) required to secure a sufficient creepage distance between the connection terminal 27a or the connection terminal 27b and the heat dissipation surface F is reduced, and the height of the semiconductor module 100 can be suppressed.

[0052] 3. Third Embodiment Figure 6 is an enlarged cross-sectional view of the vicinity of the second main surface 12 in the semiconductor module 100 of the third embodiment. The second main surface 12 of the third embodiment includes a base surface 31, a stepped surface 32a1, a connecting surface 33a1, a stepped surface 32b1, and a connecting surface 33b1, similar to the first embodiment.

[0053] In the third embodiment, similar to the second embodiment, two parallel grooves 34a1 and 34a2 are formed on the stepped surface 32a1. In the second embodiment, groove 34a1 is formed at a position spaced apart from the connecting surface 33a1. In the third embodiment, groove 34a1 is formed continuously with the connecting surface 33a1. That is, the inner wall surface 341 of groove 34a1 is continuous with the connecting surface 33a1 between the base surface 31 and the stepped surface 32a1. In other words, in the third embodiment, the distance Ea1 between the connecting surface 33a1 and groove 34a1 is 0.

[0054] Similarly, in the third embodiment, a groove 34b1 is formed continuously with the connecting surface 33b1. That is, the inner wall surface 341 of the groove 34b1 is continuous with the connecting surface 33b1 between the base surface 31 and the stepped surface 32b1. In other words, in the third embodiment, the distance Eb1 between the connecting surface 33b1 and the groove 34b1 is 0.

[0055] The same effects as in the second embodiment are achieved in the third embodiment. In the third embodiment, the inner wall surface 341 of groove 34a1 is continuous with the connecting surface 33a1, and the inner wall surface 341 of groove 34b1 is continuous with the connecting surface 33b1. Therefore, compared to the configuration in the second embodiment where groove 34a1 is spaced apart from the connecting surface 33a1 and groove 34b1 is spaced apart from the connecting surface 33b1, the change in shape of the second main surface 12 of the housing 10 is suppressed. Therefore, the concentration of stress on the second main surface 12 of the housing 10 can be suppressed. Furthermore, according to the third embodiment, compared to the configuration in the second embodiment where groove 34a1 is spaced apart from the connecting surface 33a1 and groove 34b1 is spaced apart from the connecting surface 33b1, the length from the connecting surfaces 33a1 and 33b1 to the side surfaces 13a and 13b of the stepped surfaces 32a1 and 32b1 can be reduced. Therefore, the semiconductor module 100 can be miniaturized.

[0056] On the other hand, in the second embodiment, the groove 34a1 is formed spaced apart from the connection surface 33a1. Therefore, compared to the configuration in which the groove 34a1 is continuous with the connection surface 33a1 (third embodiment), it is easier to secure a creepage distance between the connection terminal 27a and the heat dissipation surface F. Similarly, in the second embodiment, since the groove 34b1 is formed spaced apart from the connection surface 33b1, it is easier to secure a creepage distance between the connection terminal 27b and the heat dissipation surface F. In other words, the height of the housing 10 (distance between the first main surface 11 and the base surface 31) required to secure a sufficient creepage distance between the connection terminal 27a or the connection terminal 27b and the heat dissipation surface F can be reduced.

[0057] 4. Fourth Embodiment Figure 7 is an enlarged cross-sectional view of the vicinity of the second main surface 12 in the semiconductor module 100 of the fourth embodiment. The second main surface 12 of the fourth embodiment includes a base surface 31, a stepped surface 32a1, a connecting surface 33a1, a stepped surface 32b1, and a connecting surface 33b1, similar to the first embodiment.

[0058] In the fourth embodiment, similar to the third embodiment, parallel grooves 34a1 and 34a2 are formed on the stepped surface 32a1. As illustrated in Figure 7, in the fourth embodiment, the depths Da1 of groove 34a1 and Da2 of groove 34a2 are different. Specifically, the depth Da1 of groove 34a1 is less than the depth Da2 of groove 34a2. On the other hand, the widths Wa1 of groove 34a1 and Wa2 of groove 34a2 are the same. It should be noted that configurations in which the depth Da1 of groove 34a1 exceeds the depth Da2 of groove 34a2, or configurations in which the widths Wa1 of groove 34a1 and Wa2 of groove 34a2 are different, are also conceivable.

[0059] Similarly, in the fourth embodiment, the depth Db1 of groove 34b1 and the depth Db2 of groove 34b2 are different. Specifically, the depth Db1 of groove 34b1 is less than the depth Db2 of groove 34b2. On the other hand, the width Wb1 of groove 34b1 and the width Wb2 of groove 34b2 are the same. Configurations in which the depth Db1 of groove 34b1 exceeds the depth Db2 of groove 34b2, or configurations in which the width Wb1 of groove 34b1 and the width Wb2 of groove 34b2 are different are also conceivable.

[0060] The same effects as in the third embodiment are achieved in the fourth embodiment. However, if both grooves 34a1 and 34a2 are excessively deep, it may not be possible to ensure sufficient mechanical strength of the housing 10. In the fourth embodiment, the depth Da1 of groove 34a1 and the depth Da2 of groove 34a2 are different. Specifically, the depth Da1 of groove 34a1 is reduced compared to the depth Da2 of groove 34a2. Therefore, it is easier to ensure the mechanical strength of the housing 10 compared to the configuration in which grooves 34a1 and 34a2 are constrained to the same depth (third embodiment). Similarly, in the fourth embodiment, the depth Db1 of groove 34b1 and the depth Db2 of groove 34b2 are different, so it is easier to ensure the mechanical strength of the housing 10 compared to the configuration in which grooves 34b1 and 34b2 are constrained to the same depth (third embodiment).

[0061] In the above description, as in the third embodiment, an example was given in which groove 34a1 is continuous with the connecting surface 33a1 and groove 34b1 is continuous with the connecting surface 33b1. However, as in the second embodiment, an example in which groove 34a1 is spaced apart from the connecting surface 33a1 and groove 34b1 is spaced apart from the connecting surface 33b1 may also be applied to the fourth embodiment.

[0062] 5. Fifth Embodiment Figure 8 is an enlarged cross-sectional view of the vicinity of the second main surface 12 in the semiconductor module 100 of the fifth embodiment. In the fifth embodiment, the second main surface 12 includes a base surface 31, a stepped surface 32a1, a connecting surface 33a1, a stepped surface 32b1, and a connecting surface 33b1, as well as a stepped surface 32a2, a connecting surface 33a2, a stepped surface 32b2, and a connecting surface 33b2. Stepped surfaces 32a1 and 32b1 are examples of "first stepped surfaces," and stepped surfaces 32a2 and 32b2 are examples of "second stepped surfaces."

[0063] The stepped surface 32a2 is a region of the second main surface 12 located between the stepped surface 32a1 and the side surface 13a in a plan view. Similar to the stepped surface 32a1, the stepped surface 32a2 is a horizontal, flat surface of the second main surface 12 that aligns with the XY plane and extends in the Y direction along the entire length of the housing 10 in the Y direction. The stepped surface 32a2 is a surface that is recessed relative to the stepped surface 32a1 toward the first main surface 11 (+Z direction). That is, the stepped surface 32a2 is located between the first main surface 11 and the stepped surface 32a1 in the Z direction. In other words, the stepped surface 32a2 is located closer to the first main surface 11 than the stepped surface 32a1. Therefore, the stepped surface 32a2 faces the surface C of the cooler 90 with a gap between them.

[0064] The connecting surface 33a2 is a wall surface that connects the stepped surface 32a1 and the stepped surface 32a2. That is, the connecting surface 33a2 intersects with both the stepped surface 32a1 and the stepped surface 32a2. The height difference Sa2 between the connecting surface 33a1 and the connecting surface 33a2 is less than the height difference Sa1 between the foundation surface 31 and the stepped surface 32a1.

[0065] In the second to fourth embodiments, a configuration in which both groove 34a1 and groove 34a2 are formed on the stepped surface 32a1 is illustrated. In the fifth embodiment, groove 34a1 is formed on the stepped surface 32a1, while groove 34a2 is formed on the stepped surface 32a2. Groove 34a2 is a recess formed on the stepped surface 32a2 that is recessed toward the first main surface 11. Specifically, groove 34a2 extends linearly along the extension direction (Y direction) of the side surface 13a. In Figure 8, a configuration in which groove 34a2 is continuous with the connecting surface 33a2 is illustrated, but groove 34a2 may be spaced apart from the connecting surface 33a2 in the -X direction.

[0066] The stepped surface 32b2 is a region of the second main surface 12 located between the stepped surface 32b1 and the side surface 13b in a plan view. Similar to the stepped surface 32b1, the stepped surface 32b2 is a horizontal, flat surface of the second main surface 12 that aligns with the XY plane and extends in the Y direction along the entire length of the housing 10 in the Y direction. The stepped surface 32b2 is a surface that is recessed relative to the stepped surface 32b1 toward the first main surface 11 (+Z direction). That is, the stepped surface 32b2 is located between the first main surface 11 and the stepped surface 32b1 in the Z direction. In other words, the stepped surface 32b2 is located closer to the first main surface 11 than the stepped surface 32b1. Therefore, the stepped surface 32b2 faces the surface C of the cooler 90 with a gap between them.

[0067] The connecting surface 33b2 is a wall surface that connects the stepped surface 32b1 and the stepped surface 32b2. That is, the connecting surface 33b2 intersects with the stepped surfaces 32b1 and 32b2. The height difference Sb2 between the connecting surface 33b1 and the connecting surface 33b2 is less than the height difference Sb1 between the foundation surface 31 and the stepped surface 32b1.

[0068] In the second to fourth embodiments, a configuration in which both groove 34b1 and groove 34b2 are formed on the stepped surface 32b1 is illustrated. In the fifth embodiment, groove 34b1 is formed on the stepped surface 32b1, while groove 34b2 is formed on the stepped surface 32b2. Groove 34b2 is a recess formed on the stepped surface 32b2 that is recessed toward the first main surface 11. Specifically, groove 34b2 extends linearly in the Y direction along the extending direction (Y direction) of the side surface 13b. In Figure 8, a configuration in which groove 34b2 is continuous with the connecting surface 33b2 is illustrated, but groove 34b2 may be spaced apart from the connecting surface 33b2 in the +X direction.

[0069] The same effects as in the third embodiment are achieved in the fifth embodiment. In addition, in the fifth embodiment, a groove 34a1 is formed on the stepped surface 32a1, and a groove 34a2 is formed on the stepped surface 32a2 that is recessed toward the first main surface 11 relative to the stepped surface 32a1. Therefore, compared to the configuration in which only a groove 34a1 is formed (first embodiment), or the configuration in which both a groove 34a1 and a groove 34a2 are formed on the stepped surface 32a1 (second to fourth embodiments), it is easier to secure a creepage distance between the connection terminal 27a and the heat dissipation surface F. Similarly, in the fifth embodiment, a groove 34b1 is formed on the stepped surface 32b1, and a groove 34b2 is formed on the stepped surface 32b2 that is recessed toward the first main surface 11 relative to the stepped surface 32b1. Therefore, it is easier to secure a creepage distance between the connection terminal 27b and the heat dissipation surface F.

[0070] 6. Sixth Embodiment Figure 9 is a plan view of the semiconductor module 100 of the sixth embodiment as seen from the -Z direction. In the sixth embodiment, similar to the second embodiment, grooves 34a1 and 34a2 are formed on the stepped surface 32a1 of the second main surface 12, and grooves 34b1 and 34b2 are formed on the stepped surface 32b1.

[0071] As illustrated in Figure 9, the groove 34a2 formed on the stepped surface 32a1 includes a plurality of portions 35 that are spaced apart from each other along the extension direction (Y direction) of the side surface 13a. That is, the groove 34a2 in the second embodiment is formed continuously along the Y axis, whereas the groove 34a2 in the sixth embodiment is formed intermittently along the Y axis.

[0072] Specifically, each portion 35 of the groove 34a2 is formed for each set of two or more adjacent connection terminals 27a in the Y direction (hereinafter referred to as "terminal group G"). A portion 35 corresponding to any one terminal group G among the multiple portions 35 extends in the Y direction over the range where two or more connection terminals 27a constituting that terminal group G exist. Therefore, the distance between two adjacent portions 35 in the Y direction is located within the distance between two adjacent terminal groups G in the Y direction.

[0073] As described above, in the sixth embodiment, the groove 34a2 is composed of a plurality of portions 35 arranged at intervals from each other along the extending direction (Y direction) of the side surface 13a. That is, no groove 34a2 is formed between two adjacent portions 35 in the Y direction. Therefore, compared to a configuration in which the groove 34a2 is continuous in the Y direction along the entire length of the housing 10, it is easier to ensure the mechanical strength of the housing 10. The number and arrangement of each portion 35 of the groove 34a2 are not particularly limited and can be changed as desired, as long as the creepage distance between the connection terminal 27a and the heat dissipation surface F is ensured and the mechanical strength of the housing 10 is ensured. For example, each of the plurality of portions 35 may be formed for each connection terminal 27a.

[0074] On the other hand, in the sixth embodiment, a plurality of side grooves 14 are formed on the side surface 13b of the housing 10. Each side groove 14 is a recess extending along the Z direction on the side surface 13b. Specifically, a side groove 14 is formed between two adjacent connection terminals 27b out of a plurality of connection terminals 27b protruding from the side surface 13b. Specifically, a side groove 14 is formed between two connection terminals 27b with a large voltage difference out of a plurality of connection terminals 27b. With the above configuration, compared to a configuration in which no side grooves 14 are formed, there is an advantage in that it is easier to secure creepage distance between each adjacent connection terminal 27b in the Y direction. Figure 9 shows a first range R1 in which a plurality of side grooves 14 are arranged in the Y direction.

[0075] In the sixth embodiment, the groove 34b2 formed on the stepped surface 32b1 is continuous along the Y-axis within a second range R2 corresponding to a first range R1 in which the multiple side grooves 14 are arranged. The second range R2 is the range that encompasses the first range R1 in the Y direction and is a part of the stepped surface 32b1 in the Y direction. No groove 34b2 is formed in the third range R3 of the stepped surface 32b1, which is outside the second range R2. On the other hand, the groove 34b1 is continuous along the entire length of the stepped surface 32b1 in the Y direction, as in the embodiments described above. That is, the groove 34b1 is formed across both the second range R2 and the third range R3.

[0076] As described above, in the sixth embodiment, the grooves 34b2 are continuous within the second range R2 corresponding to the first range R1 in which the multiple side grooves 14 are arranged within the housing 10. Therefore, for the connection terminals 27b in which securing the creepage distance by the side grooves 14 is prioritized, it is easier to secure the creepage distance from the heat dissipation surface F. In other words, the height of the housing 10 (distance between the first main surface 11 and the base surface 31) required to secure a sufficient creepage distance between the connection terminals 27b and the heat dissipation surface F can be reduced.

[0077] In the above explanation, an example was given in which the groove 34b2 formed on the stepped surface 32b1 is formed within the second range R2. However, a configuration in which the groove 34b1 of the stepped surface 32b1 is formed within the second range R2, or a configuration in which both groove 34b1 and groove 34b2 are formed within the second range R2, can also be adopted.

[0078] Furthermore, while the above description illustrates a configuration in which the groove 34a2 is composed of multiple parts 35, the groove 34a2 is not limited to being formed by multiple parts 35. For example, a configuration in which the groove 34a1 is intermittently composed of multiple parts 35, or a configuration in which the groove 34b1 or groove 34b2 is composed of multiple parts 35 is also conceivable. In addition, in a configuration in which only the groove 34a1 is provided on the stepped surface 32a1 and only the groove 34b1 is provided on the stepped surface 32b1 (first embodiment), a configuration in which the groove 34a1 is intermittently composed of multiple parts 35 is also conceivable.

[0079] 7. Seventh Embodiment Figure 10 is a plan view of the semiconductor module 100 of the seventh embodiment as seen from the -Z direction. As illustrated in Figure 10, the semiconductor module 100 of the seventh embodiment is equipped with a plurality of auxiliary terminals 28 (28a1, 28a2, 28b1, 28b2) in addition to elements similar to those of the first embodiment. Each auxiliary terminal 28 is an auxiliary terminal that does not directly contribute to the operation of the semiconductor module 100. For example, a suspension terminal for holding the mounting substrate 21 during the manufacturing process of the semiconductor module 100 is exemplified as an auxiliary terminal 28. Inside the housing 10, the auxiliary terminals 28 are electrically connected, for example, to a conductive pattern 213 of the mounting substrate 21 that is set to ground potential among a plurality of conductive patterns 213.

[0080] Auxiliary terminals 28a1 and 28b1 are installed on the side surface 13c of the housing 10. Specifically, auxiliary terminal 28a1 is installed on the part of side surface 13c closer to side surface 13a, and auxiliary terminal 28b1 is installed on the part of side surface 13c closer to side surface 13b. On the other hand, auxiliary terminals 28a2 and 28b2 are installed on the side surface 13d of the housing 10. Specifically, auxiliary terminal 28a2 is installed on the part of side surface 13d closer to side surface 13a, and auxiliary terminal 28b2 is installed on the part of side surface 13d closer to side surface 13b.

[0081] The stepped surface 32a1 of the seventh embodiment includes an extending region 41a that extends linearly in the Y direction, as well as an end region 42a1 and an end region 42a2. In a plan view, the end region 42a1 is the region that protrudes in the +X direction from the +Y direction end of the extending region 41a. In a plan view, the end region 42a2 is the region that protrudes in the +X direction from the -Y direction end of the extending region 41a. Similarly, the stepped surface 32b1 includes an extending region 41b that extends linearly in the Y direction, as well as an end region 42b1 and an end region 42b2. In a plan view, the end region 42b1 is the region that protrudes in the -X direction from the +Y direction end of the extending region 41b. In a plan view, the end region 42b2 is the region that protrudes in the -X direction from the -Y direction end of the extending region 41b.

[0082] A groove 34a1 is formed in the stepped surface 32a1. The groove 34a1 of the seventh embodiment includes an extended portion 45a and two ends 46a1 and 46a2. The extended portion 45a is the part that extends along the extension direction (Y direction) of the side surface 13a in the extended region 41a of the stepped surface 32a1. The ends 46a1 and 46a2 are parts that are continuous with the extended portion 45a. The end 46a1 protrudes in the +X direction from the +Y direction end of the extended portion 45a. That is, the end 46a1 extends in the X direction along the side surface 13c within the end region 42a1. Therefore, in a plan view, the end 46a1 is located between the auxiliary terminal 28a1 and the base surface 31. The end 46a2 also protrudes in the +X direction from the -Y direction end of the extended portion 45a. In other words, end portion 46a2 extends in the X direction along the side surface 13d within the end portion region 42a2. Therefore, in a plan view, end portion 46a2 is located between the auxiliary terminal 28a2 and the base surface 31. Note that the extended portion 45a is an example of the "first portion," and end portions 46a1 and 46a2 are examples of the "second portion."

[0083] A groove 34b1 is formed in the stepped surface 32b1. The groove 34b1 of the seventh embodiment includes an extended portion 45b and two ends 46b1 and 46b2. The extended portion 45b is the part that extends along the extension direction (Y direction) of the side surface 13b in the extended region 41b of the stepped surface 32b1. The ends 46b1 and 46b2 are parts that are continuous with the extended portion 45b. The end 46b1 protrudes in the -X direction from the +Y direction end of the extended portion 45b. That is, the end 46b1 extends in the X direction along the side surface 13c within the end region 42b1. Therefore, in a plan view, the end 46b1 is located between the auxiliary terminal 28b1 and the base surface 31. The end 46b2 also protrudes in the -X direction from the -Y direction end of the extended portion 45b. In other words, end portion 46b2 extends in the X direction along the side surface 13d within the end portion region 42b2. Therefore, in a plan view, end portion 46b2 is located between the auxiliary terminal 28b2 and the base surface 31. Note that the extended portion 45b is an example of the "first portion," and end portions 46b1 and 46b2 are examples of the "second portion."

[0084] The same effects as in the first embodiment are achieved in the seventh embodiment. In the seventh embodiment, the groove 34a1 includes an extended portion 45a along the extension direction (Y direction) of the side surface 13a from which the connection terminal 27a protrudes, an end portion 46a1 along the side surface 13c from which the auxiliary terminal 28a1 protrudes, and an end portion 46a2 along the side surface 13d from which the auxiliary terminal 28a2 protrudes. Therefore, in addition to the creepage distance between each connection terminal 27a and the heat dissipation surface F, it is also easy to secure the creepage distance between each of the auxiliary terminals 28a1 and 28a2 and the heat dissipation surface F. Similarly, in the seventh embodiment, since the groove 34b1 includes an extended portion 45b and end portions 46b1 and 46b2, it is easy to secure the creepage distance between each of the auxiliary terminals 28b1 and 28b2 and the heat dissipation surface F. In other words, the height of the housing 10 (the distance between the first main surface 11 and the base surface 31) required to ensure a sufficient creepage distance between each auxiliary terminal 28 and the heat dissipation surface F can be reduced.

[0085] 8. Variations The following are examples of specific modifications that may be added to the embodiments illustrated above. Two or more embodiments arbitrarily selected from the following examples may be combined as appropriate, within the bounds of consistency.

[0086] (1) The form (e.g., dimensions or shape) of the grooves 34 (34a1, 34a2, 34b1, 34b2) formed on the second main surface 12 may be arbitrarily changed. For example, in the above-described embodiments, a configuration in which each groove 34 is formed in a straight line along the Y axis was illustrated, but each groove 34 may be formed in a curved shape (e.g., a wavy line) along the Y axis. Furthermore, the cross-sectional shape of each groove 34 is not limited to the rectangular shape illustrated in the above-described embodiments and can be changed to any shape. For example, as illustrated in Figure 11, the cross-sectional shape of each groove 34 may be triangular. Also, as illustrated in Figure 12, the cross-sectional shape of each groove 34 may be semicircular. As can be understood from the example in Figure 12, the inner wall surface of the groove 34 does not have to consist only of a flat surface, but may include a curved surface such as an arc surface.

[0087] (2) In the first to fifth embodiments, the configuration of the groove 34 formed on the stepped surface 32a1 (for example, dimensions or shape) and the configuration of the groove 34 formed on the stepped surface 32b1 were shown to be common. However, the configuration of the groove 34 (34a1, 34a2) on the stepped surface 32a1 and the configuration of the groove 34 (34b1, 34b2) on the stepped surface 32b1 may be different.

[0088] For example, as illustrated in Figure 13, the total number of grooves 34 formed on the stepped surface 32a1 may differ from the total number of grooves 34 formed on the stepped surface 32b1. For example, the voltage difference between each connection lead 23 and the heat sink 212 is sufficiently greater than the voltage difference between each control lead 24 and the heat sink 212. Therefore, ensuring the creepage distance between each connection lead 23 and the heat sink F takes precedence over ensuring the creepage distance between each control lead 24 and the heat sink F. Considering these circumstances, as illustrated in Figure 13, a configuration in which the total number of grooves 34 formed on the stepped surface 32a1 (two grooves, grooves 34a1 and 34a2) exceeds the total number of grooves 34 formed on the stepped surface 32b1 (one groove, groove 34b1 only) is preferable. For similar reasons, a configuration in which the depth Da1 of the groove 34a1 formed on the stepped surface 32a1 exceeds the depth Db1 of the groove 34b1 formed on the stepped surface 32b1 is also preferable.

[0089] (3) In the above-described embodiments, a configuration in which grooves 34 (34a1, 34a2, 34b1, 34b2) are formed on both the stepped surface 32a1 and the stepped surface 32b1 has been illustrated, but grooves 34 may be formed on only one of the stepped surface 32a1 or the stepped surface 32b1.

[0090] For example, in the embodiment illustrated in Figure 14, a groove 34a1 similar to that in the first embodiment is formed on the stepped surface 32a1 corresponding to the side surface 13a of the housing 10. The side surface 13a corresponding to the stepped surface 32a1 is the side surface 13 of the housing 10 from which the connection terminals 27a of each connection lead 23 electrically connected to the main electrode of the semiconductor chip 22 protrude. On the other hand, the stepped surface 32b1 corresponding to the side surface 13b is a flat surface from which no groove 34 is formed. The side surface 13b corresponding to the stepped surface 32b1 is the side surface 13 from which the connection terminals 27a of each connection lead 23 electrically connected to the main electrode of the semiconductor chip 22 do not protrude.

[0091] A higher voltage is applied to each connection terminal 27a compared to each connection terminal 27b. Therefore, it is important to ensure a sufficient creepage distance between each connection terminal 27a and the heat dissipation surface F compared to each connection terminal 27b. In the configuration of Figure 14, grooves 34a1 are formed on the stepped surface 32a1 close to each connection terminal 27a, making it easier to ensure a sufficient creepage distance between each connection terminal 27a and the heat dissipation surface F. On the other hand, the stepped surface 32b1 located on the opposite side of the multiple connection terminals 27a is a flat surface without grooves. Therefore, there is an advantage in that it is easier to maintain mechanical strength for the stepped surface 32b1. Note that the grooves 34a1 in the configuration of Figure 14 can be arbitrarily applied from the configurations exemplified in the second to seventh embodiments and each modified example.

[0092] (4) In the embodiments described above, a fully molded semiconductor module 100 in which the housing 10 and the semiconductor unit 20 are integrally formed by transfer molding was exemplified. However, the present disclosure also applies to semiconductor modules in which the semiconductor unit 20 is housed in a rectangular frame-shaped resin case and a sealing material such as resin material is filled into the resin case, in the same manner as the embodiments described above. That is, the term "housing" in this disclosure is comprehensively expressed as a structure that houses a mounting substrate, and includes both a resin mold integrally formed with the mounting substrate (semiconductor unit) and a resin case that surrounds the mounting substrate (semiconductor unit).

[0093] (5) In the embodiments described above, the semiconductor chip 22 is shown as an RC-IGBT, but the type of semiconductor chip 22 can be changed as desired. For example, the semiconductor chip 22 may consist of a single IGBT or FWD. Alternatively, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) in which the semiconductor layer is made of silicon (Si) or silicon carbide (SiC) may be used as the semiconductor chip 22.

[0094] (6) The notation "nth" (where n is a natural number) in this application is used solely as a formal and convenient label to distinguish each element in notation and has no substantive meaning whatsoever. Therefore, there is no room for restrictive interpretation of the position or manufacturing order of each element based on the notation "nth".

[0095] 9. Addendum From the forms exemplified above, the following configuration can be understood, for example.

[0096] A semiconductor module according to one aspect of the present disclosure (Aspect 1) comprises a housing including a first main surface and a second main surface facing opposite directions from each other, and a side surface between the first main surface and the second main surface; a mounting substrate housed in the housing; a semiconductor chip mounted on the mounting substrate; and a connection terminal protruding from the side surface. The second main surface includes a base surface with an opening formed therein and a first stepped surface located between the base surface and the side surface in a plan view, recessed toward the first main surface relative to the base surface; the mounting substrate includes a heat dissipation surface located inside the opening; and the first stepped surface has a first groove recessed toward the first main surface and along the extending direction of the side surface. In the above aspect, the first groove along the extending direction of the side surface in the housing is formed on the second main surface (first stepped surface). Therefore, it is easy to secure creepage distance between the connection terminal and the heat dissipation surface. In other words, the height of the housing (distance between the first main surface and the base surface) required to ensure a sufficient creepage distance between the connection terminals and the heat dissipation surface can be reduced. Furthermore, a first groove is formed on the first stepped surface of the second main surface of the housing, which is recessed toward the first main surface relative to the base surface. Therefore, in a configuration where the base surface and the cooler face each other via a heat conductive material, the possibility of the heat conductive material entering the first groove can be reduced compared to a configuration where the first groove is formed on the base surface. Consequently, a shortage of heat conductive material between the base surface and the cooler can be suppressed.

[0097] In a specific example of Embodiment 1 (Embodiment 2), a second groove parallel to the first groove is formed on the first stepped surface. In the above embodiment, both the first groove and the second groove are formed on the first stepped surface of the housing. Therefore, compared to a configuration in which only the first groove is formed on the first stepped surface, it is easier to secure a creepage distance between the connection terminal and the heat dissipation surface. In other words, the height of the housing (distance between the first main surface and the base surface) required to secure a sufficient creepage distance between the connection terminal and the heat dissipation surface can be reduced.

[0098] In a specific example of Embodiment 2 (Embodiment 3), the first groove is shallower than the second groove. In the above embodiments, the depth of the first groove and the depth of the second groove are different. Therefore, compared to a configuration in which the first groove and the second groove are constrained to the same depth, it is easier to ensure both the mechanical strength of the housing and the creepage distance between the connection terminals and the heat dissipation surface.

[0099] In a specific example of Embodiment 1 (Embodiment 4), the second main surface further includes a second stepped surface located between the first stepped surface and the side surface in a plan view, recessed toward the first main surface relative to the first stepped surface, and a second groove is formed in the second stepped surface, recessed toward the first main surface and along the extending direction of the side surface. In the above embodiment, a first groove is formed on the first stepped surface, and a second groove is formed on the second stepped surface recessed toward the first main surface relative to the first stepped surface. Therefore, compared to a configuration in which only the first groove is formed, or a configuration in which both the first and second grooves are formed on the first stepped surface, it is easier to secure a creepage distance between the connection terminal and the heat dissipation surface. In other words, the height of the housing (distance between the first main surface and the base surface) required to secure a sufficient creepage distance between the connection terminal and the heat dissipation surface can be reduced.

[0100] In any specific example of Embodiments 2 to 4 (Embodiment 5), at least one of the first groove and the second groove includes a plurality of portions that are spaced apart from each other along the extending direction of the side surface. According to the above embodiments, it is easier to ensure the mechanical strength of the housing compared to a configuration in which the first groove and the second groove are continuous along the entire length of the housing.

[0101] In any specific example of Embodiments 1 to 5 (Embodiment 6), the distance (e.g., height difference) between the base surface and the first stepped surface is 1 mm or more. Compared to a configuration in which the distance between the base surface and the first stepped surface is less than 1 mm, the aforementioned effect of securing creepage distance between the connection terminal and the surface of the cooler is particularly significant.

[0102] In any specific example of Embodiments 1 to 6 (Embodiment 7), the first groove includes a plurality of portions arranged at intervals from one another along the extending direction of the side surface. According to the above embodiments, it is easier to ensure the mechanical strength of the housing compared to a configuration in which the first groove is continuous along the entire length of the housing.

[0103] In any specific example (8) of embodiments 1 to 7, the first groove is formed spaced apart from the connecting surface between the base surface and the first stepped surface. In the embodiments described above, the first groove is formed spaced apart from the connecting surface. Therefore, compared to a configuration in which the inner wall surface of the first groove is continuous with the connecting surface, it is easier to secure a creepage distance between the connection terminal and the heat dissipation surface. In other words, the height of the housing (distance between the first main surface and the base surface) required to secure a sufficient creepage distance between the connection terminal and the heat dissipation surface can be reduced.

[0104] In any specific example (9) of Embodiments 1 to 7, the inner wall surface of the first groove is continuous with the connecting surface between the base surface and the first stepped surface. In the above embodiments, the inner wall surface of the first groove is continuous with the connecting surface. Therefore, compared to a configuration in which the first groove is spaced apart from the connecting surface, the change in shape of the second main surface of the housing is suppressed. Therefore, the concentration of stress on the second main surface of the housing can be suppressed.

[0105] In any specific example of Embodiments 1 to 9 (Embodiment 10), the first groove is continuous along the entire length of the housing along the extension direction of the side surface. According to the above embodiments, since the first groove is continuous along the entire length of the housing, it is easy to secure a creepage distance between the connection terminals and the heat dissipation surface along the entire length of the housing. In other words, the height of the housing (distance between the first main surface and the base surface) required to secure a sufficient creepage distance between the connection terminals and the heat dissipation surface can be reduced.

[0106] In any specific example of Embodiments 1 to 10 (Embodiment 11), an auxiliary terminal is further provided, the side surface includes a first side surface from which the connection terminal protrudes and a second side surface intersecting the first side surface, the auxiliary terminal protrudes from the second side surface, and the first groove includes a first portion extending along the extension direction of the first side surface and a second portion continuous with the first portion and extending along the extension direction of the second side surface. In the above embodiment, the first groove includes a first portion along the extension direction of the first side surface from which the connection terminal protrudes and a second portion along the second side surface from which the auxiliary terminal protrudes. Therefore, in addition to the creepage distance between the connection terminal and the heat dissipation surface, it is also easy to secure a creepage distance between the auxiliary terminal and the heat dissipation surface. In other words, the height of the housing (distance between the first main surface and the base surface) required to secure a sufficient creepage distance between the auxiliary terminal and the heat dissipation surface can be reduced. Furthermore, in each of the above-described embodiments, sides 13a and 13b are examples of the "first side" in embodiment 11, and sides 13c and 13d are examples of the "second side" in embodiment 11.

[0107] In any specific example of Embodiments 1 to 11 (Embodiment 12), a plurality of connection terminals, including the connection terminal, protrude from the side surface, and a plurality of side grooves extending from the first main surface toward the second main surface are formed on the side surface between adjacent connection terminals, and the first groove is continuous along the direction in which the plurality of side grooves are arranged in the housing within a second range corresponding to a first range in the housing along the extending direction of the side surface. In the above embodiment, since side grooves are formed on the side surface of the housing, it is easy to secure a creepage distance between adjacent connection terminals. Also, since the first groove is continuous over the range in the housing where the plurality of side grooves are arranged, it is easy to secure a creepage distance between each connection terminal and the heat dissipation surface. In other words, the height of the housing (distance between the first main surface and the base surface) required to secure a sufficient creepage distance between the connection terminal and the heat dissipation surface can be reduced.

[0108] In any specific example of Embodiments 1 to 12 (Embodiment 13), the side surface includes a first side surface and a third side surface facing opposite directions between the first main surface and the second main surface, the connection terminal has a portion of the connection lead electrically connected to the main electrode of the semiconductor chip that protrudes from the first side surface, the second main surface further includes a second stepped surface located between the base surface and the third side surface in a plan view and recessed toward the first main surface relative to the base surface, the first stepped surface is located between the base surface and the first side surface in a plan view and recessed toward the first main surface relative to the base surface, and no groove is formed on the second stepped surface. Since the connection terminal electrically connected to the main electrode of the semiconductor chip is installed on the first stepped surface of the housing, it is particularly important to ensure a sufficient creepage distance between the connection terminal and the heat dissipation surface. According to Embodiment 13, since a first groove is formed on the first stepped surface, it is easy to ensure a creepage distance between the connection terminal and the heat dissipation surface. On the other hand, the second stepped surface located between the base surface and the third side surface of the second main surface is a flat surface in which no groove is formed. Therefore, there is an advantage in that it is easier to maintain mechanical strength for the second stepped surface. Note that side surface 13a in each of the above embodiments is an example of the "first side surface" in embodiment 13, and side surface 13b is an example of the "third side surface" in embodiment 13.

[0109] A semiconductor module according to one aspect of the present disclosure (Aspect 14) comprises a housing including a first main surface and a second main surface facing opposite directions from each other, a first side surface and a third side surface facing opposite directions between the first main surface and the second main surface, a mounting substrate housed in the housing, a semiconductor chip mounted on the mounting substrate, a first connection terminal protruding from the first side surface, and a second connection terminal protruding from the third side surface, wherein the second main surface has a base surface in which an opening is formed, and in plan view, the base The mounting substrate includes a first stepped surface located between the surface and the first side surface and recessed toward the first main surface relative to the base surface, and a second stepped surface located between the base surface and the third side surface in a plan view and recessed toward the first main surface relative to the base surface, wherein the mounting substrate includes a heat dissipation surface located inside the opening, the first stepped surface has a first groove recessed toward the first main surface and along the extending direction of the first side surface, and the second stepped surface has a second groove recessed toward the first main surface and along the extending direction of the third side surface. In the above embodiment, since the first groove and the second groove are formed on the second main surface (first stepped surface), it is easy to secure creepage distance between both the first and second connection terminals and the heat dissipation surface. In other words, the height of the housing (distance between the first main surface and the base surface) required to secure sufficient creepage distance between both the first and second connection terminals and the heat dissipation surface can be reduced. Furthermore, the first and second grooves are formed on the stepped surfaces (first stepped surface, second stepped surface) of the second main surface of the housing that are recessed toward the first main surface relative to the base surface. Therefore, in a configuration in which the base surface and the cooler face each other via a heat conductive material, the possibility of the heat conductive material entering the first or second groove can be reduced compared to a configuration in which the first and second grooves are formed on the base surface. Thus, a shortage of heat conductive material between the base surface and the cooler can be suppressed. Note that side surface 13a in each of the above embodiments is an example of the "first side surface" in embodiment 14, and side surface 13b is an example of the "third side surface" in embodiment 14. [Explanation of Symbols]

[0110] 100...Semiconductor module, 10...Housing, 11...First main surface, 12...Second main surface, 13(13a,13b,13c,13d)...Side, 14...Side groove, 20...Semiconductor unit, 21...Mounting board, 211...Insulating board, 212...Heat sink, 213...Conductive pattern, 22...Semiconductor chip, 23...Connection lead, 24...Control lead, 25...Control chip, 26...Wire, 27a,27b...Connection terminal, 28a1,28a2,28b1,28b2...Auxiliary Terminal, 31...Foundation surface, 311...Opening, 32a1,32a2,32b1,32b2...Step surface, 33a1,33a2,33b1,33b2...Connection surface, 34a1,34a2,34b1,34b2...Groove, 341...Inner wall surface, 3 5... Each part of the groove, 41a, 41b... extension area, 42a1, 42a2, 42b1, 42b2... end area, 45a, 45b... extension part, 46a1, 46a2, 46b1, 46b2... end, 90... cooler, 91... thermal conductive material.

Claims

1. A housing including a first main surface and a second main surface facing opposite directions, and a side surface between the first main surface and the second main surface, The mounting substrate housed in the aforementioned housing, A semiconductor chip mounted on the aforementioned mounting substrate, The connection terminal protruding from the aforementioned side It is equipped with, The second main surface is, The foundation surface in which the opening is formed, In a plan view, it includes a first stepped surface located between the base surface and the side surface, and recessed toward the first main surface relative to the base surface, The aforementioned mounting substrate includes a heat dissipation surface located inside the opening, The first stepped surface has a recess on the first main surface side and a first groove that runs along the extension direction of the side surface. Semiconductor module.

2. A second groove parallel to the first groove is formed on the first stepped surface. A semiconductor module according to claim 1.

3. The first groove is shallower than the second groove. The semiconductor module according to claim 2.

4. The second main surface further includes a second stepped surface located between the first stepped surface and the side surface in a plan view, and recessed toward the first main surface relative to the first stepped surface. The second stepped surface has a recess on the first main surface side and a second groove that runs along the extension direction of the side surface. A semiconductor module according to claim 1.

5. At least one of the first groove and the second groove includes a plurality of portions that are spaced apart from each other along the extending direction of the side surface. A semiconductor module according to any one of claims 2 to 4.

6. The distance between the base surface and the first stepped surface is 1 mm or more. A semiconductor module according to claim 1.

7. The first groove includes a plurality of portions that are spaced apart from each other along the extension direction of the side surface. A semiconductor module according to claim 1.

8. The first groove is formed spaced apart from the connecting surface between the base surface and the first stepped surface. A semiconductor module according to claim 1.

9. The inner wall surface of the first groove is continuous with the connecting surface between the foundation surface and the first stepped surface. A semiconductor module according to claim 1.

10. The first groove is continuous along the length of the housing along the extension direction of the side surface. A semiconductor module according to claim 1.

11. It is further equipped with auxiliary terminals, The aforementioned side is, The first side surface from which the aforementioned connection terminal protrudes, Including a second surface intersecting the first surface, The auxiliary terminal protrudes from the second side surface, The first groove is A first portion extending along the extension direction of the first side surface, It includes a second portion that is continuous with the first portion and extends along the direction of extension of the second side surface. A semiconductor module according to claim 1.

12. Multiple connection terminals, including the aforementioned connection terminal, protrude from the side surface. Between adjacent connection terminals among the plurality of connection terminals, a plurality of side grooves extending in the direction from the first main surface toward the second main surface are formed on the side surface. The first groove is Within the containment, in the second range corresponding to the first range in which the plurality of side grooves are arranged in a direction along the extension direction of the side surface, continuous along that direction A semiconductor module according to claim 1.

13. The aforementioned side surface includes a first side surface and a third side surface that face opposite each other between the first main surface and the second main surface, The aforementioned connection terminal has a portion of the connection lead that is electrically connected to the main electrode of the semiconductor chip and protrudes from the first side surface. The second main surface further includes a second stepped surface located between the base surface and the third side surface in a plan view, and recessed toward the first main surface relative to the base surface. The first stepped surface is located between the base surface and the first side surface in a plan view, and is a portion that is recessed toward the first main surface relative to the base surface. No grooves are formed on the second stepped surface. A semiconductor module according to claim 1.

14. A encapsulant comprising a first main surface and a second main surface facing opposite directions from each other, and a first side surface and a third side surface facing opposite directions between the first main surface and the second main surface, The mounting substrate housed in the aforementioned housing, A semiconductor chip mounted on the aforementioned mounting substrate, A first connection terminal protruding from the first side surface, The second connection terminal protruding from the third side and It is equipped with, The second main surface is, The foundation surface in which the opening is formed, In a plan view, a first stepped surface is located between the base surface and the first side surface, and is recessed toward the first main surface side relative to the base surface, In a plan view, it includes a second stepped surface located between the base surface and the third side surface, and recessed toward the first main surface side relative to the base surface, The aforementioned mounting substrate includes a heat dissipation surface located inside the opening, The first stepped surface has a first groove formed in which there is a recess on the first main surface side and which is aligned with the extension direction of the first side surface. The second stepped surface has a recess on the first main surface side and a second groove that runs along the extension direction of the third side surface. Semiconductor module.

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