Semiconductor module

Abstract

The present application relates to a semiconductor module, which suppresses shortage of a thermally conductive material provided to a heat dissipation surface and ensures an along-surface distance of a connection terminal from the heat dissipation surface. The semiconductor module includes a housing including a first main surface and a second main surface facing in 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 to the mounting substrate; and a connection terminal protruding from the side surface. The second main surface includes a base surface formed with an opening, and a first step surface located between the base surface and the side surface when viewed from above, which is recessed toward the first main surface side with respect to the base surface. The mounting substrate includes a heat dissipation surface located inside the opening, and a first groove along the side surface is formed in the first step surface.

Description

Technical Field

[0001] This disclosure relates to semiconductor modules. Background Technology

[0002] Semiconductor modules with multiple connection terminals protruding from the housing portion have been proposed in the past (Patent Documents 1 to 5). For example, Patent Document 1 discloses a structure in which a groove is formed in the area between adjacent lead terminals on the lower surface of the semiconductor package, thereby ensuring the surface distance between the lead terminals.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2022-131370

[0006] Patent Document 2: International Publication No. 2023 / 210379

[0007] Patent Document 3: Japanese Patent No. 6752381

[0008] Patent Document 4: Japanese Patent Application Publication No. 2007-73743

[0009] Patent Document 5: International Publication No. 2017 / 175612 Summary of the Invention

[0010] The problem the invention aims to solve

[0011] The bottom surface of a semiconductor module serves as a heat dissipation surface. For example, consider a structure where the heat dissipation surface of the semiconductor module is separated from a cooler (e.g., a heat sink) by a thermally conductive material such as thermal grease. However, in structures where grooves are formed on the bottom surface of the semiconductor module to ensure surface clearance, the thermally conductive material enters the grooves, potentially resulting in insufficient thermally conductive material between the semiconductor module and the cooler. Considering the above, one objective of this disclosure is to suppress insufficient thermally conductive material on the heat dissipation surface and ensure adequate surface clearance between the connection terminals and the heat dissipation surface.

[0012] Solution for solving the problem

[0013] A semiconductor module according to one technical solution of this disclosure includes: a housing comprising 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; 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 having an opening; and a first stepped surface located between the base surface and the side surface when viewed from above, recessed relative to the base surface towards the first main surface. The mounting substrate includes a heat dissipation surface located inside the opening, and a first groove is formed on the first stepped surface that is recessed towards the first main surface and extends along the direction of the side surface.

[0014] Another semiconductor module disclosed herein comprises: a housing including a first main surface and a second main surface facing opposite directions, and 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. The second main surface includes: a base surface having an opening; a first stepped surface located between the base surface and the first side surface in a top view, recessed relative to the base surface towards the first main surface; and a second stepped surface located between the base surface and the third side surface in a top view, recessed relative to the base surface towards the first main surface. The mounting substrate includes a heat dissipation surface located inside the opening. A first groove is formed on the first stepped surface, recessed towards the first main surface and extending along the direction of the first side surface. A second groove is formed on the second stepped surface, recessed towards the first main surface and extending along the direction of the third side surface. Attached Figure Description

[0015] Figure 1 This is a cross-sectional view of the semiconductor module according to the first embodiment.

[0016] Figure 2 This is a top view of the semiconductor module viewed from the -Z direction.

[0017] Figure 3 It is an enlarged cross-sectional view of the vicinity of the second main surface of the semiconductor module.

[0018] Figure 4 This is a top view of the semiconductor module of the second embodiment viewed from the -Z direction.

[0019] Figure 5 This is a cross-sectional view near the second main surface of the semiconductor module in the second embodiment.

[0020] Figure 6This is a cross-sectional view near the second main surface of the semiconductor module in the third embodiment.

[0021] Figure 7 This is a cross-sectional view near the second main surface of the semiconductor module in the fourth embodiment.

[0022] Figure 8 This is a cross-sectional view near the second main surface of the semiconductor module in the fifth embodiment.

[0023] Figure 9 This is a top view of the semiconductor module of the sixth embodiment viewed from the -Z direction.

[0024] Figure 10 This is a top view of the semiconductor module of the seventh embodiment viewed from the -Z direction.

[0025] Figure 11 This is a cross-sectional view near the second main surface of the modified semiconductor module.

[0026] Figure 12 This is a cross-sectional view near the second main surface of the modified semiconductor module.

[0027] Figure 13 This is a top view of the modified semiconductor module viewed from the -Z direction.

[0028] Figure 14 This is a top view of the modified semiconductor module viewed from the -Z direction.

[0029] Explanation of reference numerals in the attached figures

[0030] 100. Semiconductor module; 10. Repository; 11. First main surface; 12. Second main surface; 13 (13a, 13b, 13c, 13d), side surface; 14. Side groove; 20. Semiconductor unit; 21. Mounting substrate; 211. Insulating substrate; 212. Heat sink; 213. Conductive pattern; 22. Semiconductor chip; 23. Connecting lead; 24. Control lead; 25. Control chip; 26. Wire; 27a, 27b, Connecting terminals; 28a1, 28a2, 28b1, 28b2, Auxiliary terminals; 31. Base surface; 311, opening; 32a1, 32a2, 32b1, 32b2, stepped surface; 33a1, 33a2, 33b1, 33b2, connecting surface; 34a1, 34a2, 34b1, 34b2, groove; 341, inner wall surface; 35, various parts of the groove; 41a, 41b, extension area; 42a1, 42a2, 42b1, 42b2, end area; 45a, 45b, extension; 46a1, 46a2, 46b1, 46b2, end; 90, cooler; 91, thermally conductive material. Detailed Implementation

[0031] The embodiments for carrying out this disclosure will be described with reference to the accompanying drawings. Furthermore, in the drawings, the dimensions and scales of the elements may sometimes differ from those of the actual product. Additionally, the following description is an illustrative approach contemplated for carrying out this disclosure. Therefore, the scope of this disclosure is not limited to the illustrative approaches described below.

[0032] 1. First Implementation Method

[0033] Figure 1 This is a cross-sectional view of a semiconductor module 100 according to a first embodiment of this disclosure. The semiconductor module 100 of the first embodiment is, for example, a power semiconductor module used in a power conversion device such as an inverter circuit.

[0034] In the following explanation, we assume three orthogonal axes (X-axis, Y-axis, and Z-axis). The direction along the X-axis (+X direction and -X direction) will be denoted as the "X direction". Similarly, the direction along the Y-axis (+Y direction and -Y direction) will be denoted as the "Y direction", and the direction along the Z-axis (+Z direction and -Z direction) will be denoted as the "Z direction".

[0035] In practical use, the semiconductor module 100 can be positioned in any orientation. However, for convenience, in the following description, the +Z direction is assumed to be upward and the -Z direction is assumed to be downward. Therefore, sometimes the surface of any element of the semiconductor module 100 facing the +Z direction is referred to as the "upper surface," and the surface of that element facing the -Z direction is referred to as the "lower surface." Furthermore, in the following description, the view of any element of the semiconductor module 100 viewed through a line of sight along the Z direction is referred to as "top view." Additionally, the directions of the three orthogonal axes (X direction, Y direction, Z direction) are independent of the direction of gravity.

[0036] Figure 2 This is a top view of the semiconductor module 100 viewed from the -Z direction. That is, in... Figure 2 The middle figure shows the lower surface of the semiconductor module 100. (As shown) Figure 1 and Figure 2 As illustrated, the semiconductor module 100 of the first embodiment includes a housing 10 and a semiconductor unit 20.

[0037] The housing 10 is a structure that houses the semiconductor unit 20. The housing 10 is formed, for example, from a thermoplastic resin or a thermosetting resin. Examples of thermoplastic resins include PPS (polyphenylene sulfide), PBT (polybutylene terephthalate), PBS (polybutylene succinate), PA (polyamide), or ABS (acrylonitrile-butadiene-styrene). Examples of thermosetting resins include epoxy resin. For example, the housing 10 and the semiconductor unit 20 are integrally formed by transfer molding, which fills a molding die containing the semiconductor unit 20 with liquid resin material. As described above, the semiconductor module 100 of the first embodiment is a fully molded semiconductor package.

[0038] The storage body 10 is formed as a flat, generally rectangular parallelepiped shape, including a first main surface 11 and a second main surface 12 facing opposite directions, and a side surface 13 between the first main surface 11 and the second main surface 12. The first main surface 11 is the generally rectangular upper surface (top surface) of the storage body 10 facing the +Z direction. The second main surface 12 is the generally rectangular lower surface (bottom surface) of the storage body 10 facing the -Z direction. The Z direction is the direction from one of the first main surface 11 and the second main surface 12 towards the other, corresponding to the thickness direction (height direction) of the storage body 10.

[0039] Side 13 is the outer wall surface connecting the first main surface 11 and the second main surface 12. Specifically, side 13 includes side 13a, side 13b, side 13c, and side 13d. Side 13a and side 13b are outer wall surfaces facing opposite directions between the first main surface 11 and the second main surface 12. Specifically, side 13a is the region in side 13 of the storage body 10 facing the -X direction. Side 13b is the region in side 13 of the storage body 10 facing the +X direction. That is, the Y direction represents the direction in which side 13a or side 13b extends when viewed from above (hereinafter referred to as the "extension direction").

[0040] Side surfaces 13c and 13d are outer wall surfaces facing opposite directions between the first main surface 11 and the second main surface 12. Specifically, side surface 13c is the region in side surface 13 of the housing 10 facing the +Y direction. Side surface 13d is the surface in side surface 13 of the housing 10 facing the -Y direction. That is, each side surface 13a and side surface 13b intersects with each side surface 13c and side surface 13d when viewed from above.

[0041] like Figure 1As illustrated, the semiconductor unit 20 includes a mounting substrate 21, a semiconductor chip 22, connecting leads 23, control leads 24, and a control chip 25. The mounting substrate 21 is a wiring substrate 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 is used as the mounting substrate 21. The mounting substrate 21 is housed in the housing 10.

[0042] The mounting substrate 21 is constructed by stacking an insulating substrate 211, a heat sink 212, and a conductive pattern 213. The insulating substrate 211 is a rectangular plate-shaped member formed of an insulating material. The insulating substrate 211 is formed, for example, of ceramic materials such as alumina, aluminum nitride, or silicon nitride, or of resin materials such as epoxy resin.

[0043] The heat sink 212 is a plate-shaped member that is bonded to the -Z-oriented surface (i.e., the lower surface) of the insulating substrate 211. The heat sink 212 is formed, for example, from a metal material with high thermal conductivity such as copper or aluminum. The -Z-oriented surface (hereinafter referred to as "heat dissipation surface F") of the heat sink 212 is opposite to the surface C of the cooler 90. The cooler 90 is, for example, a heat dissipation member such as a radiator.

[0044] A thermally conductive material 91 is provided between the heat dissipation surface F of the mounting substrate 21 and the surface C of the cooler 90. The thermally conductive material 91 is, for example, a fluid thermally conductive material such as thermal grease. Heat transferred from the semiconductor chip 22 to the insulating substrate 211 is transferred from the heat dissipation surface F to the cooler 90 via the thermally conductive material 91. That is, the heat dissipation surface F is the surface used for heat dissipation of the semiconductor module 100. In addition, the heat sink 212 can also be used as a grounding body set to ground potential.

[0045] The conductive pattern 213 is a thin film or plate-like conductor disposed on the surface (i.e., the upper surface) facing the +Z direction in the insulating substrate 211. For example, the conductive pattern 213 is formed from a low-resistance conductive material such as copper or a copper alloy.

[0046] Semiconductor chip 22 is a power semiconductor element disposed on mounting substrate 21, used as a switching element for switching current on / off. In the first embodiment, semiconductor chip 22 is, for example, an RC-IGBT (Reverse Conducting IGBT) comprising an IGBT (Insulated Gate Bipolar Transistor) and a FWD (Free Wheeling Diode). Semiconductor chip 22 is bonded to conductive pattern 213, for example, by a conductive bonding material (not shown) such as solder or sintering material. Semiconductor chip 22 is housed in housing 10. Furthermore, in practice, multiple semiconductor chips 22 are disposed on mounting substrate 21, but... Figure 2 For simplicity, only one semiconductor chip 22 is shown in the figure.

[0047] Connecting lead 23 is a lead frame that is electrically connected to semiconductor chip 22. For example... Figure 2 As illustrated, the semiconductor module 100 has a plurality of interconnecting leads 23 that are separate from each other. Each interconnecting lead 23 extends from the interior of the housing 10 through the side 13a and is exposed to the external space. The portion of each interconnecting lead 23 located inside the housing 10 is electrically connected to the main electrode (e.g., collector or emitter) of the semiconductor chip 22.

[0048] The portion of each connecting lead 23 exposed to the external space (hereinafter referred to as "connecting terminal 27a") protrudes from the side 13a of the housing 10 in the -X direction. That is, on the side 13a of the housing 10, a plurality of connecting terminals 27a protruding outward from the side 13a (in the -X direction) are arranged spaced apart from each other in the Y direction. Each connecting terminal 27a is a conductor for electrically connecting the semiconductor unit 20 to an external device such as a power supply device or a load device. Specifically, the plurality of connecting terminals 27a includes a power supply terminal (P terminal) for a high-side power supply voltage, a power supply terminal (N terminal) for a low-side power supply voltage, and output terminals (U terminal, V terminal, W terminal) for supplying power to a load device such as a motor.

[0049] Control lead 24 is a lead frame used to control the semiconductor module 100. For example... Figure 2 As illustrated, the semiconductor module 100 has a plurality of control leads 24 that are separate from each other. Each control lead 24 extends from the interior of the housing 10 through the side 13b and is exposed to the external space. A control chip 25 is mounted on the portion of each control lead 24 located inside the housing 10. The control chip 25 is housed within the housing 10.

[0050] 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, via a wire 26. As described above, the semiconductor module 100 of the first embodiment is an intelligent power module (IPM) with the control chip 25 built in. However, the control chip 25 can be omitted from the semiconductor module 100.

[0051] The portion of each control lead 24 exposed to external space (hereinafter referred to as "connection terminal 27b") protrudes from the side 13b of the housing 10 in the +X direction. That is, on the side 13b of the housing 10, a plurality of connection terminals 27b protruding outward from the side 13b (in the +X direction) are arranged spaced apart 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.

[0052] Figure 3 This is an enlarged cross-sectional view of the vicinity of the second main surface 12 of the storage body 10. For example... Figure 2 and Figure 3 As illustrated, the second main surface 12 of the storage body 10 includes a base surface 31, a step surface 32a1, a connecting surface 33a1, a step surface 32b1, and a connecting surface 33b1. In a top view, the base surface 31 is located between the step surface 32a1 and the step surface 32b1.

[0053] The base surface 31 is a horizontal, flat surface along the XY plane in the second main surface 12. An opening 311 is formed in the base surface 31. The mounting substrate 21 is disposed inside the opening 311 when viewed from above. That is, the inner wall surface of the opening 311 of the housing 10 is in close contact with the outer wall surface of the mounting substrate 21. Therefore, the heat dissipation surface F of the mounting substrate 21 is exposed inside the opening 311. That is, the base surface 31 is a frame-shaped plane that surrounds the heat dissipation surface F throughout its entire circumference. Figure 1 As illustrated, the base surface 31 of the housing 10 and the heat dissipation surface F of the mounting substrate 21 are located on the same surface, and the heat dissipation surface F of the mounting substrate 21 is exposed from the base surface 31.

[0054] like Figure 2 As illustrated, the stepped surface 32a1 is the region of the second main surface 12 located between the base surface 31 and the side surface 13a when viewed from above. The stepped surface 32a1 is a horizontal, flat surface along the XY plane in the second main surface 12, extending along the Y direction along the entire length of the housing 10. Figure 1 and Figure 3As illustrated, the step surface 32a1 is a surface recessed relative to the base surface 31 towards the first main surface 11 (in the +Z direction). That is, the step surface 32a1 is located between the first main surface 11 and the second main surface 12 in the Z direction. In other words, the step surface 32a1 is located closer to the first main surface 11 in the Z direction than the base surface 31. Therefore, as... Figure 1 As illustrated, the stepped surface 32a1 is spaced apart from the surface C of the cooler 90.

[0055] The connecting surface 33a1 is the wall surface connecting the base surface 31 and the step surface 32a1. That is, the connecting surface 33a1 intersects with both the base surface 31 and the step surface 32a1. Figure 3 As illustrated, the height difference Sa1 between the base surface 31 and the step surface 32a1 is equivalent 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 step surface 32a1 and the surface C of the cooler 90. However, the value of the height difference Sa1 is not limited to the above range and can be arbitrarily changed.

[0056] A groove 34a1 is formed on the step surface 32a1. The groove 34a1 is a recessed portion that is recessed towards the first main surface 11 relative to the step surface 32a1. Specifically, as... Figure 2 As illustrated, the groove 34a1 extends in a straight line along the extension direction (Y direction) of the side surface 13a when viewed from above. In the first embodiment, the groove 34a1 extends along the entire length of the receiving body 10 (or the stepped surface 32a1) in the Y direction. The groove 34a1 is formed at a position separated from the connecting surface 33a1 in the -X direction.

[0057] like Figure 3 As illustrated, the cross-sectional shape of the groove 34a1 is rectangular (e.g., a cuboid or trapezoidal shape). The depth Da1 of the groove 34a1 is less than the distance Ha between the lower surface of the connecting terminal 27a and the step surface 32a1. The depth Da1 is the distance between the bottom surface of the groove 34a1 and the step surface 32a1. For example, the depth Da1 of the groove 34a1 is less than half of the distance Ha between the lower surface of the connecting terminal 27a and the step surface 32a1. Furthermore, the depth Da1 of the groove 34a1 is equal to the height difference Sa1 between the base surface 31 and the step surface 32a1. In addition, 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.

[0058] like Figure 2 As illustrated, the stepped surface 32b1 is the region of the second main surface 12 located between the base surface 31 and the side surface 13b when viewed from above. The stepped surface 32b1 is a horizontal, flat surface in the second main surface 12 along the XY plane, extending along the Y direction along the entire length of the housing 10. Figure 1 and Figure 3 As illustrated, the step surface 32b1 is a surface recessed relative to the base surface 31 towards the first main surface 11 (in the +Z direction). That is, the step surface 32b1 is located between the first main surface 11 and the second main surface 12 in the Z direction. In other words, the step surface 32b1 is located closer to the first main surface 11 in the Z direction than the base surface 31. Therefore, as... Figure 1 As illustrated, the stepped surface 32b1 is spaced apart from the surface C of the cooler 90.

[0059] Connecting surface 33b1 is the wall surface connecting base surface 31 and step surface 32b1. That is, connecting surface 33b1 intersects with both base surface 31 and step surface 32b1. Figure 3 As illustrated, the height difference Sb1 between the base surface 31 and the step surface 32b1 is equivalent 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 step surface 32b1 and the surface C of the cooler 90. However, the value of the height difference Sb1 is not limited to the above range and can be arbitrarily changed.

[0060] A groove 34b1 is formed on the step surface 32b1. The groove 34b1 is a recessed portion that is recessed towards the first main surface 11 relative to the step surface 32b1. Specifically, as... Figure 2 As illustrated, the groove 34b1 extends in a straight line along the extension direction (Y direction) of the side surface 13b when viewed from above. In the first embodiment, the groove 34b1 extends along the Y direction along the entire length of the receiving body 10 (or the stepped surface 32b1). The groove 34b1 is formed at a position separated from the connecting surface 33b1 in the +X direction.

[0061] like Figure 3 As illustrated, the cross-sectional shape of the groove 34b1 is rectangular (e.g., a cuboid or trapezoidal shape). The depth Db1 of the groove 34b1 is less than the distance Hb between the lower surface of the connecting terminal 27b and the step surface 32b1. The depth Db1 is the distance between the bottom surface of the groove 34b1 and the step surface 32b1. Furthermore, the depth Db1 of the groove 34b1 is equal to the height difference Sb1 between the base surface 31 and the step surface 32b1. Additionally, 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.

[0062] As described above, in the first embodiment, a groove 34a1 extending along the Y-direction of the side surface 13a of the housing 10 is formed on the second main surface 12 (stepped surface 32a1). Therefore, it is easy to ensure the surface distance between the connecting terminal 27a and the heat dissipation surface F. Similarly, a groove 34b1 extending along the Y-direction of the side surface 13b of the housing 10 is formed on the second main surface 12 (stepped surface 32b1). Therefore, it is easy to ensure the surface distance between the connecting terminal 27b 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 surface distance between the connecting terminal 27a or the connecting terminal 27b and the heat dissipation surface F can be reduced. In the first embodiment, in particular, grooves 34a1 and 34b1 are formed on the second main surface 12. Therefore, compared to a structure that only has one of slots 34a1 and slot 34b1, it has the advantage of easily ensuring the surface distance between the connection terminals 27a and 27b and the heat dissipation surface F.

[0063] Furthermore, in the first embodiment, a groove 34a1 is formed on the stepped surface 32a1 of the second main surface 12 of the housing 10, which is recessed towards the first main surface 11 relative to the base surface 31. Therefore, compared to the structure in which the groove 34a1 is formed on the base surface 31, the possibility of the heat-conducting material 91 entering the groove 34a1 can be reduced. Similarly, a groove 34b1 is formed on the stepped surface 32b1 of the second main surface 12 of the housing 10, which is recessed towards the first main surface 11 relative to the base surface 31. Therefore, compared to the structure in which the groove 34b1 is formed on the base surface 31, the possibility of the heat-conducting material 91 entering the groove 34b1 can be reduced. As a result of suppressing the heat-conducting material 91 from entering the groove 34a1 or the groove 34b1, the heat-conducting material 91 is uniformly spread between the base surface 31 and the cooler 90. Therefore, the deficiency of heat-conducting material 91 between the base surface 31 and the cooler 90 can be suppressed.

[0064] Furthermore, the depth Da1 of the groove 34a1 is preferably less than half the distance Ha between the lower surface of the connecting terminal 27a and the step surface 32a1. If the depth Da1 of the groove 34a1 is greater than half the distance Ha, the connecting terminal 27a will be close to the bottom surface of the groove 34a1, and the mechanical strength of the housing 10 will decrease. With the structure that the depth Da1 of the groove 34a1 is less than half the distance Ha, the mechanical strength of the housing 10 can be maintained.

[0065] In the first embodiment, in particular, the groove 34a1 is continuous along the entire length of the housing 10 along the extension direction of the side surface 13a. Therefore, it is easy to ensure the surface distance between the plurality of connection terminals 27a and the heat dissipation surface F along the entire length of the housing 10 in the Y direction. Similarly, the groove 34b1 is continuous along the extension direction of the side surface 13b along the entire length of the housing 10, thus it is easy to ensure the surface distance between the plurality of connection terminals 27b and the heat dissipation surface F along the entire length of the housing 10 in the Y direction.

[0066] Furthermore, in the first embodiment, the height difference Sa1 between the base surface 31 and the step surface 32a1 is 1 mm or more. That is, a gap of 1 mm or more is ensured between the step surface 32a1 and the surface C of the cooler 90. This ensures the surface distance between the connecting terminal 27a and the surface C of the cooler 90. Similarly, in the first embodiment, the height difference Sb1 between the base surface 31 and the step surface 32b1 is 1 mm or more, thus effectively ensuring the surface distance between the connecting terminal 27b and the surface C of the cooler 90.

[0067] 2. Second Implementation Method

[0068] Next, the second embodiment will be described. Furthermore, for elements that function the same as in the first embodiment in the various embodiments illustrated below, the same reference numerals as in the description of the first embodiment will be used, and detailed descriptions of each element will be omitted as appropriate.

[0069] Figure 4 This is a top view of the semiconductor module 100 of the second embodiment viewed from the -Z direction. Figure 5 This is an enlarged cross-sectional view of the vicinity of the second main surface 12 of the semiconductor module 100. The second main surface 12 of the second embodiment also includes a base surface 31, a step surface 32a1, a connecting surface 33a1, a step surface 32b1, and a connecting surface 33b1, just like the first embodiment.

[0070] like Figure 4 and Figure 5 As illustrated, in addition to the groove 34a1 formed in the first embodiment, a groove 34a2 parallel to the groove 34a1 is also formed on the stepped surface 32a1. That is, the grooves 34a1 and 34a2 are adjacent to each other at intervals in the X direction. The groove 34a2 is a recess formed between the side surface 13a and the groove 34a1 in the stepped surface 32a1 and recessed towards the first main surface 11. The groove 34a2 extends linearly along the extension direction (Y direction) of the side surface 13a, just like the groove 34a1. Specifically, the groove 34a2 extends along the Y direction along the entire length of the housing 10 (or the stepped surface 32a1) in the Y direction.

[0071] The cross-sectional shape of groove 34a2 is the same as that of groove 34a1, which is rectangular (e.g., rectangular or trapezoidal). 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 connecting terminal 27a and the step surface 32a1. In addition, 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.

[0072] 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. In addition, the distance Ea3 between the side surface 13a and the groove 34a2 is also, for example, 0.5 mm or more.

[0073] like Figure 4 and Figure 5 As illustrated, in addition to the groove 34b1 formed in the first embodiment, a groove 34b2 parallel to the groove 34b1 is also formed on the stepped surface 32b1. That is, the grooves 34b1 and 34b2 are adjacent to each other at intervals in the X direction. The groove 34b2 is a recess formed between the side surface 13b and the groove 34b1 in the stepped surface 32b1 and recessed towards the first main surface 11. The groove 34b2 extends linearly along the extension direction (Y direction) of the side surface 13b, just like the groove 34b1. Specifically, the groove 34b2 extends along the Y direction along the entire length of the housing 10 (or the stepped surface 32b1) in the Y direction.

[0074] The cross-sectional shape of groove 34b2 is the same as that of groove 34b1, which is rectangular (e.g., rectangular or trapezoidal). 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 connecting terminal 27b and step surface 32b1. In addition, 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.

[0075] 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. In addition, the distance Eb3 between the side surface 13b and the groove 34b2 is also, for example, 0.5 mm or more.

[0076] In the second embodiment, the same effect as in the first embodiment is achieved. Furthermore, in the second embodiment, grooves 34a1 and 34a2 are formed on the stepped surface 32a1 of the housing 10. Therefore, compared to a structure where only groove 34a1 is formed on the stepped surface 32a1 (e.g., in the first embodiment), it is easier to ensure the surface distance between the connection terminal 27a and the heat dissipation surface F. Similarly, grooves 34b1 and 34b2 are formed on the stepped surface 32b1 of the housing 10, thus easily ensuring the surface distance between the connection terminal 27b and the heat dissipation surface F. Furthermore, since the surface distances between the connection terminal 27a and the connection terminal 27b and the heat dissipation surface F can be ensured more reliably, the height of the housing 10 (the distance between the first main surface 11 and the base surface 31) required to ensure sufficient surface distance between the connection terminal 27a or the connection terminal 27b and the heat dissipation surface F can be reduced, thus suppressing the height of the semiconductor module 100.

[0077] 3. Third Implementation Method

[0078] Figure 6 This is an enlarged cross-sectional view of the vicinity of the second main surface 12 of the semiconductor module 100 of the third embodiment. The second main surface 12 of the third embodiment includes, similarly to that of the first embodiment, a base surface 31, a step surface 32a1, a connecting surface 33a1, a step surface 32b1, and a connecting surface 33b1.

[0079] In the third embodiment, similarly to the second embodiment, parallel grooves 34a1 and 34a2 are formed on the step surface 32a1. In the second embodiment, groove 34a1 is formed at a position separate 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 step surface 32a1. In other words, in the third embodiment, the interval Ea1 between the connecting surface 33a1 and groove 34a1 is 0.

[0080] Similarly, in the third embodiment, the 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 step surface 32b1. In other words, in the third embodiment, the interval Eb1 between the connecting surface 33b1 and the groove 34b1 is 0.

[0081] In the third embodiment, the same effect as in the second embodiment is achieved. Furthermore, in the third embodiment, the inner wall surface 341 of the groove 34a1 is continuous with the connecting surface 33a1, and the inner wall surface 341 of the groove 34b1 is continuous with the connecting surface 33b1. Therefore, compared to the structure where the groove 34a1 and the connecting surface 33a1 are separated, and the groove 34b1 and the connecting surface 33b1 are separated (in the second embodiment), the change in the shape of the second main surface 12 of the housing 10 is suppressed. Therefore, stress concentration on the second main surface 12 of the housing 10 can be suppressed. Additionally, according to the third embodiment, compared to the structure where the groove 34a1 and the connecting surface 33a1 are separated, and the groove 34b1 and the connecting surface 33b1 are separated (in the second embodiment), the length from the connecting surfaces 33a1 and 33b1 of the stepped surfaces 32a1 and 32b1 to the side surfaces 13a and 13b can be reduced. Therefore, miniaturization of the semiconductor module 100 can be achieved.

[0082] On the other hand, in the second embodiment, the groove 34a1 is formed separately from the connecting surface 33a1. Therefore, compared with the structure where the groove 34a1 and the connecting surface 33a1 are continuous (third embodiment), it is easier to ensure the surface distance between the connecting terminal 27a and the heat dissipation surface F. Similarly, in the second embodiment, since the groove 34b1 is formed separately from the connecting surface 33b1, it is easier to ensure the surface distance between the connecting terminal 27b 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 surface distance between the connecting terminal 27a or the connecting terminal 27b and the heat dissipation surface F can be reduced.

[0083] 4. Fourth Implementation Method

[0084] Figure 7 This is an enlarged cross-sectional view of the vicinity of the second main surface 12 of the semiconductor module 100 of the fourth embodiment. The second main surface 12 of the fourth embodiment includes, similarly to that of the first embodiment, a base surface 31, a step surface 32a1, a connecting surface 33a1, a step surface 32b1, and a connecting surface 33b1.

[0085] In the fourth embodiment, similarly to the third embodiment, parallel grooves 34a1 and 34a2 are formed on the stepped surface 32a1. For example... Figure 7 As illustrated, in the fourth embodiment, the depth Da1 of groove 34a1 is different from the depth Da2 of groove 34a2. Specifically, the depth Da1 of groove 34a1 is less than the depth Da2 of groove 34a2. On the other hand, the width Wa1 of groove 34a1 is the same as the width Wa2 of groove 34a2. Furthermore, it is also contemplated that the depth Da1 of groove 34a1 is greater than the depth Da2 of groove 34a2, or that the width Wa1 of groove 34a1 is different from the width Wa2 of groove 34a2.

[0086] Similarly, in the fourth embodiment, the depth Db1 of groove 34b1 is different from the depth Db2 of groove 34b2. 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 is the same as the width Wb2 of groove 34b2. It is also conceivable that the depth Db1 of groove 34b1 is greater than the depth Db2 of groove 34b2, or that the width Wb1 of groove 34b1 is different from the width Wb2 of groove 34b2.

[0087] In the fourth embodiment, the same effect as in the third embodiment is achieved. However, in structures where both grooves 34a1 and 34a2 are too deep, there is a possibility that the mechanical strength of the housing 10 cannot be sufficiently ensured. In the fourth embodiment, the depth Da1 of groove 34a1 is different from the depth Da2 of groove 34a2. Specifically, the depth Da1 of groove 34a1 is reduced compared to the depth Da2 of groove 34a2. Therefore, compared to a structure where grooves 34a1 and 34a2 are limited to the same depth (the third embodiment), it is easier to ensure the mechanical strength of the housing 10. Similarly, in the fourth embodiment, since the depth Db1 of groove 34b1 is different from the depth Db2 of groove 34b2, compared to a structure where grooves 34b1 and 34b2 are limited to the same depth (the third embodiment), it is easier to ensure the mechanical strength of the housing 10.

[0088] Furthermore, in the above description, the method in which the trench 34a1 and the connecting surface 33a1 are continuous, and the trench 34b1 and the connecting surface 33b1 are continuous, as in the third embodiment, can also be applied to the fourth embodiment in the manner in which the trench 34a1 and the connecting surface 33a1 are separated, and the trench 34b1 and the connecting surface 33b1 are separated, as in the second embodiment.

[0089] 5. Fifth Implementation Method

[0090] Figure 8 This is an enlarged cross-sectional view of the vicinity of the second main surface 12 of the semiconductor module 100 according to the fifth embodiment. In addition to the base surface 31, step surface 32a1, connecting surface 33a1, step surface 32b1, and connecting surface 33b1, the second main surface 12 of the fifth embodiment also includes step surface 32a2, connecting surface 33a2, step surface 32b2, and connecting surface 33b2. Furthermore, step surface 32a1 and step surface 32b1 are examples of a "first step surface," and step surface 32a2 and step surface 32b2 are examples of a "second step surface."

[0091] Step surface 32a2 is the region in the second main surface 12 located between step surface 32a1 and side surface 13a when viewed from above. Similar to step surface 32a1, step surface 32a2 is a horizontal, flat surface in the second main surface 12 along the XY plane, extending along the Y direction along the entire length of the housing 10 in the Y direction. Step surface 32a2 is a surface recessed relative to step surface 32a1 towards the first main surface 11 (+Z direction). That is, step surface 32a2 is located between the first main surface 11 and step surface 32a1 in the Z direction. In other words, step surface 32a2 is located closer to the first main surface 11 than step surface 32a1. Therefore, step surface 32a2 is spaced apart from the surface C of the cooler 90.

[0092] The connecting surface 33a2 is the wall surface that connects the step surface 32a1 and the step surface 32a2. That is, the connecting surface 33a2 intersects with both the step surface 32a1 and the step surface 32a2. The height difference Sa2 between the step surface 32a1 and the step surface 32a2 is less than the height difference Sa1 between the base surface 31 and the step surface 32a1.

[0093] In the second to fourth embodiments, a structure is illustrated where both groove 34a1 and groove 34a2 are formed on the stepped surface 32a1. In the fifth embodiment, groove 34a1 is formed on the stepped surface 32a1, and groove 34a2 is formed on the stepped surface 32a2. Groove 34a2 is a recess formed on the stepped surface 32a2 and recessed towards the first main surface 11. Specifically, groove 34a2 extends linearly along the extending direction (Y direction) of the side surface 13a. Furthermore, in Figure 8 The diagram illustrates a structure in which the groove 34a2 is continuous with the connecting surface 33a2, but the groove 34a2 can also be separated from the connecting surface 33a2 in the -X direction.

[0094] Step surface 32b2 is the region in the second main surface 12 located between step surface 32b1 and side surface 13b when viewed from above. Similar to step surface 32b1, step surface 32b2 is a horizontal, flat surface in the second main surface 12 along the XY plane, extending along the Y direction along the entire length of the housing 10 in the Y direction. Step surface 32b2 is a surface recessed relative to step surface 32b1 towards the first main surface 11 (+Z direction). That is, step surface 32b2 is located between the first main surface 11 and step surface 32b1 in the Z direction. In other words, step surface 32b2 is located closer to the first main surface 11 than step surface 32b1. Therefore, step surface 32b2 is spaced apart from the surface C of the cooler 90.

[0095] The connecting surface 33b2 is the wall surface that connects the step surface 32b1 and the step surface 32b2. That is, the connecting surface 33b2 intersects with both the step surface 32b1 and the step surface 32b2. The height difference Sb2 between the step surface 32b1 and the step surface 32b2 is less than the height difference Sb1 between the base surface 31 and the step surface 32b1.

[0096] In the second to fourth embodiments, a structure is illustrated where both groove 34b1 and groove 34b2 are formed on the stepped surface 32b1. In the fifth embodiment, groove 34b1 is formed on the stepped surface 32b1, and groove 34b2 is formed on the stepped surface 32b2. Groove 34b2 is a recess formed on the stepped surface 32b2 and recessed towards the first main surface 11. Specifically, groove 34b2 extends linearly along the extending direction (Y direction) of the side surface 13b. Furthermore, in Figure 8 The example illustrates a structure in which the groove 34b2 is continuous with the connecting surface 33b2, but the groove 34b2 can also be separated from the connecting surface 33b2 in the +X direction.

[0097] In the fifth embodiment, the same effect as in the third embodiment is achieved. Furthermore, in the fifth embodiment, in addition to forming a groove 34a1 on the stepped surface 32a1, a groove 34a2 is also formed on the stepped surface 32a2, which is recessed towards the first main surface 11 relative to the stepped surface 32a1. Therefore, compared to the structure with only a groove 34a1 (first embodiment), or the structure with both grooves 34a1 and 34a2 formed on the stepped surface 32a1 (second to fourth embodiments), it is easier to ensure the surface distance between the connecting terminal 27a and the heat dissipation surface F. Similarly, in the fifth embodiment, in addition to forming a groove 34b1 on the stepped surface 32b1, a groove 34b2 is also formed on the stepped surface 32b2, which is recessed towards the first main surface 11 relative to the stepped surface 32b1. Therefore, it is easier to ensure the surface distance between the connecting terminal 27b and the heat dissipation surface F.

[0098] 6. Sixth Implementation Method

[0099] Figure 9 This is a top view of the semiconductor module 100 of the sixth embodiment viewed from the -Z direction. In the sixth embodiment, similar to the second embodiment, grooves 34a1 and 34a2 are formed on the step surface 32a1 of the second main surface 12, and grooves 34b1 and 34b2 are formed on the step surface 32b1.

[0100] like Figure 9 As illustrated, the groove 34a2 formed on the stepped surface 32a1 includes a plurality of portions 35 arranged at intervals along the extending direction (Y direction) of the side surface 13a. That is, the groove 34a2 of the second embodiment is formed continuously along the Y-axis, while the groove 34a2 of the sixth embodiment is formed intermittently along the Y-axis.

[0101] Specifically, each portion 35 of the slot 34a2 is formed for each set (hereinafter referred to as "terminal group G") of two or more adjacent connection terminals 27a in the Y direction. The portion 35 of the plurality of portions 35 corresponding to any one terminal group G extends along the Y direction over the area where the two or more connection terminals 27a constituting the terminal group G exist. Therefore, the interval between two adjacent portions 35 in the Y direction is located within the interval between two adjacent terminal groups G in the Y direction.

[0102] As described above, in the sixth embodiment, the groove 34a2 is composed of a plurality of portions 35 arranged at intervals 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 with a structure in which the groove 34a2 is continuous along the Y direction along the entire length of the housing 10, it is easier to ensure the mechanical strength of the housing 10. Furthermore, the number and arrangement of each portion 35 of the groove 34a2 are not particularly limited, as long as the surface distance between the connecting terminal 27a and the heat dissipation surface F is ensured, and the mechanical strength of the housing 10 is ensured, and can be arbitrarily changed. For example, each of the plurality of portions 35 may be formed for each connecting terminal 27a.

[0103] On the other hand, a plurality of side grooves 14 are formed on the side surface 13b of the housing 10 in the sixth embodiment. Each side groove 14 is a recess extending along the Z direction in the side surface 13b. Specifically, a side groove 14 is formed between two adjacent connection terminals 27b among the 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 among the plurality of connection terminals 27b. According to the above structure, compared with the structure without side grooves 14, it has the advantage of easily ensuring the surface distance between each adjacent connection terminal 27b in the Y direction. Figure 9 The figure shows a first range R1 with multiple side slots 14 arranged in the Y direction.

[0104] 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 arranged with a plurality of side grooves 14. The second range R2 is a range that includes the first range R1 in the Y direction and is a local range in the Y direction of the stepped surface 32b1. No groove 34b2 is formed in the third range R3 outside the second range R2 in the stepped surface 32b1. On the other hand, similarly to the embodiments described above, the groove 34b1 is continuous along the entire length of the stepped surface 32b1 in the Y direction. That is, the groove 34b1 is formed throughout both the second range R2 and the third range R3.

[0105] As described above, in the sixth embodiment, since the groove 34b2 is continuous within the second range R2 corresponding to the first range R1 in the housing 10 where the plurality of side grooves 14 are arranged, it has the advantage that the surface distance of the connection terminals 27b, which is preferentially ensured by utilizing the side grooves 14, is also easily ensured to the surface distance with respect to 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 sufficient surface distance between the connection terminals 27b and the heat dissipation surface F can be reduced.

[0106] Furthermore, in the above description, an example is shown of a structure in which the groove 34b2 formed on the step surface 32b1 is formed within the second range R2. However, it is also possible to use a structure in which the groove 34b1 on the step surface 32b1 is formed within the second range R2, or a structure in which both the groove 34b1 and the groove 34b2 are formed within the second range R2.

[0107] Furthermore, while the above description illustrates a groove 34a2 composed of multiple parts 35, the groove formed by multiple parts 35 is not limited to groove 34a2. For example, it is also contemplated that groove 34a1 is composed of multiple parts 35 intermittently, or that groove 34b1 or groove 34b2 is composed of multiple parts 35. Additionally, in a structure where only groove 34a1 is provided on the stepped surface 32a1 and only groove 34b1 is provided on the stepped surface 32b1 (first embodiment), it is also contemplated that groove 34a1 is composed of multiple parts 35 intermittently.

[0108] 7. Seventh Implementation Method

[0109] Figure 10 This is a top view of the semiconductor module 100 of the seventh embodiment, viewed from the -Z direction. (See attached image.) Figure 10 As illustrated, the semiconductor module 100 of the seventh embodiment, in addition to having the same elements as that of the first embodiment, also includes a plurality of auxiliary terminals 28 (28a1, 28a2, 28b1, 28b2). Each auxiliary terminal 28 is an auxiliary terminal that does not directly participate in the operation of the semiconductor module 100. For example, a suspension terminal used to hold the mounting substrate 21 during the manufacturing process of the semiconductor module 100 is exemplified as an auxiliary terminal 28. The auxiliary terminals 28 are electrically connected, for example, to a conductive pattern 213 of a plurality of conductive patterns 213 of the mounting substrate 21 that is set to a ground potential inside the housing 10.

[0110] Auxiliary terminals 28a1 and 28b1 are disposed on the side 13c of the housing 10. Specifically, auxiliary terminal 28a1 is disposed on the portion of side 13c closer to side 13a, and auxiliary terminal 28b1 is disposed on the portion of side 13c closer to side 13b. On the other hand, auxiliary terminals 28a2 and 28b2 are disposed on the side 13d of the housing 10. Specifically, auxiliary terminal 28a2 is disposed on the portion of side 13d closer to side 13a, and auxiliary terminal 28b2 is disposed on the portion of side 13d closer to side 13b.

[0111] In addition to the extension region 41a extending linearly in the Y direction, the stepped surface 32a1 of the seventh embodiment also includes an end region 42a1 and an end region 42a2. The end region 42a1 is the region that protrudes from the end in the +Y direction of the extension region 41a towards the +X direction when viewed from above. The end region 42a2 is the region that protrudes from the end in the -Y direction of the extension region 41a towards the +X direction when viewed from above. Similarly, the stepped surface 32b1 includes the extension region 41b extending linearly in the Y direction, as well as an end region 42b1 and an end region 42b2. The end region 42b1 is the region that protrudes from the end in the +Y direction of the extension region 41b towards the -X direction when viewed from above. The end region 42b2 is the region that protrudes from the end in the -Y direction of the extension region 41b towards the -X direction when viewed from above.

[0112] A groove 34a1 is formed on the stepped surface 32a1. The groove 34a1 in the seventh embodiment includes an extension 45a, an end portion 46a1, and an end portion 46a2. The extension 45a is a portion extending in the extension region 41a of the stepped surface 32a1 along the extension direction (Y direction) of the side surface 13a. The end portions 46a1 and 46a2 are continuous with the extension 45a. The end portion 46a1 protrudes from the +Y direction end portion of the extension 45a in the +X direction. That is, the end portion 46a1 extends in the X direction along the side surface 13c within the end region 42a1. Therefore, the end portion 46a1 is located between the auxiliary terminal 28a1 and the base surface 31 when viewed from above. Furthermore, the end portion 46a2 protrudes from the -Y direction end portion of the extension 45a in the +X direction. That is, the end portion 46a2 extends in the X direction along the side surface 13d within the end region 42a2. Therefore, when viewed from above, end portion 46a2 is located between auxiliary terminal 28a2 and base surface 31. Furthermore, extension 45a is an example of a "first part", and end portions 46a1 and 46a2 are examples of a "second part".

[0113] A groove 34b1 is formed on the stepped surface 32b1. The groove 34b1 in the seventh embodiment includes an extension 45b, an end portion 46b1, and an end portion 46b2. The extension 45b is a portion extending in the extension region 41b of the stepped surface 32b1 along the extension direction (Y direction) of the side surface 13b. The end portions 46b1 and 46b2 are continuous with the extension 45b. The end portion 46b1 protrudes from the +Y direction end portion of the extension 45b in the -X direction. That is, the end portion 46b1 extends in the X direction along the side surface 13c within the end region 42b1. Therefore, the end portion 46b1 is located between the auxiliary terminal 28b1 and the base surface 31 when viewed from above. Additionally, the end portion 46b2 protrudes from the -Y direction end portion of the extension 45b in the -X direction. That is, the end portion 46b2 extends in the X direction along the side surface 13d within the end region 42b2. Therefore, when viewed from above, end portion 46b2 is located between auxiliary terminal 28b2 and base surface 31. Furthermore, extension 45b is an example of a "first part," and end portions 46b1 and 46b2 are examples of a "second part."

[0114] In the seventh embodiment, the same effect as in the first embodiment is achieved. Furthermore, in the seventh embodiment, the groove 34a1 includes an extension 45a extending in the Y direction along the side surface 13a protruding from the connecting terminal 27a, an end portion 46a1 protruding along the side surface 13c protruding from the auxiliary terminal 28a1, and an end portion 46a2 protruding along the side surface 13d protruding from the auxiliary terminal 28a2. Therefore, in addition to easily ensuring the surface distance between each connecting terminal 27a and the heat dissipation surface F, it is also easy to ensure the surface distance between each auxiliary terminal 28a1 and auxiliary terminal 28a2 and the heat dissipation surface F. Similarly, in the seventh embodiment, the groove 34b1 includes an extension 45b, an end portion 46b1, and an end portion 46b2, thus easily ensuring the surface distance between each auxiliary terminal 28b1 and auxiliary terminal 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 sufficient surface distance between each auxiliary terminal 28 and the heat dissipation surface F can be reduced.

[0115] 8. Variations

[0116] The following examples illustrate specific variations that may be added to the embodiments illustrated above. Two or more embodiments chosen from the following examples may also be appropriately combined without contradiction.

[0117] (1) The shape (e.g., size or form) of the grooves 34 (34a1, 34a2, 34b1, 34b2) formed on the second main surface 12 can be arbitrarily changed. For example, in the above embodiments, each groove 34 is shown as a straight line along the Y-axis, but each groove 34 can also be formed as a curve (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 shown in the above embodiments, and can be changed to any shape. For example, as... Figure 11 As illustrated, the cross-sectional shape of each groove 34 can also be triangular. Additionally, as... Figure 12 As illustrated, the cross-sectional shape of each groove 34 can also be semi-circular. (See from...) Figure 12 As understood from the example, the inner wall surface of the groove 34 does not need to be composed of only planes; for example, it may also include curved surfaces such as arc surfaces.

[0118] (2) In the first to fifth embodiments, it is shown that the shape (e.g., size or shape) of the groove 34 formed on the step surface 32a1 and the shape of the groove 34 formed on the step surface 32b1 are common structures, but the shape of the groove 34 (34a1, 34a2) on the step surface 32a1 and the shape of the groove 34 (34b1, 34b2) on the step surface 32b1 may be different.

[0119] For example, such as Figure 13 As illustrated, the total number of slots 34 formed on the stepped surface 32a1 and the total number of slots 34 formed on the stepped surface 32b1 can also be different. For example, the voltage difference between each connecting 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 surface distance between each connecting lead 23 and the heat sink F takes priority over ensuring the surface distance between each control lead 24 and the heat sink F. Considering the above, then as Figure 13 As illustrated, it is preferable that the total number of grooves 34 formed on the step surface 32a1 (groove 34a1 and groove 34a2) is greater than the total number of grooves 34 formed on the step surface 32b1 (groove 34b1 only). Furthermore, for the same reason, it is also preferable that the depth Da1 of the groove 34a1 formed on the step surface 32a1 is greater than the depth Db1 of the groove 34b1 formed on the step surface 32b1.

[0120] (3) Among the above-described methods, a structure in which grooves 34 (34a1, 34a2, 34b1, 34b2) are formed on both the step surface 32a1 and the step surface 32b1 is illustrated, but it is also possible to form grooves 34 on only one of the step surface 32a1 and the step surface 32b1.

[0121] For example, in Figure 14In the illustrated embodiment, the stepped surface 32a1 corresponding to side surface 13a in the housing 10 has a groove 34a1 similar to that in the first embodiment. Side surface 13a corresponding to stepped surface 32a1 is the side surface 13 protruding from the connection terminals 27a of each connection lead 23 electrically connected to the main electrode of the semiconductor chip 22 in the housing 10. On the other hand, stepped surface 32b1 corresponding to side surface 13b is a flat surface without a groove 34a. Side surface 13b corresponding to stepped surface 32b1 is the side surface 13 that does not protrude from the connection terminals 27a of each connection lead 23 electrically connected to the main electrode of the semiconductor chip 22.

[0122] Compared to each connecting terminal 27b, a higher voltage is applied to each connecting terminal 27a. Therefore, ensuring sufficient surface clearance between each connecting terminal 27a and the heat dissipation surface F is important, compared to connecting terminal 27b. Figure 14 In the structure, grooves 34a1 are formed on the stepped surface 32a1 closer to each connecting terminal 27a, thus easily ensuring the surface distance between each connecting terminal 27a and the heat dissipation surface F. On the other hand, the stepped surface 32b1 located on the side opposite to the multiple connecting terminals 27a is a flat surface without grooves. Therefore, the stepped surface 32b1 has the advantage of easily maintaining mechanical strength. Furthermore, for Figure 14 The slot 34a1 in this manner can be arbitrarily applied to the structures illustrated in the second to seventh embodiments and various modifications.

[0123] (4) In the above embodiments, a fully molded semiconductor module 100 in which the housing 10 and the semiconductor unit 20 are integrally formed by transfer molding is exemplified. However, this disclosure can also be applied to semiconductor modules in which the semiconductor unit 20 is housed in a rectangular frame-shaped resin housing and the resin housing is filled with a sealing material such as resin material. That is, the term "housing body" in this disclosure is generally defined as a structure that houses a mounting substrate, including both a resin molding integrally formed with the mounting substrate (semiconductor unit) and a resin housing surrounding the mounting substrate (semiconductor unit).

[0124] (5) In the above embodiments, the semiconductor chip 22 is exemplified as an RC-IGBT, but the type of semiconductor chip 22 can be arbitrarily changed. For example, the semiconductor chip 22 can also be composed of a single IGBT or FWD. Alternatively, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) with a semiconductor layer formed of silicon (Si) or silicon carbide (SiC) can also be used as the semiconductor chip 22.

[0125] (6) The use of terms such as “nth” (where n is a natural number) in this application is merely a formal designation for distinguishing elements on a label and is for convenience. It has no substantive meaning. Therefore, the position of the elements or the order of manufacture should not be interpreted restrictively based on the use of terms such as “nth”.

[0126] 9. Postscript

[0127] Based on the examples above, for instance, understand the following structure.

[0128] One embodiment (Aspect 1) of this disclosure provides a semiconductor module comprising: 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; a mounting substrate housed within 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 having an opening; and a first stepped surface, located between the base surface and the side surface in plan view, recessed relative to the base surface towards the first main surface. The mounting substrate includes a heat dissipation surface located inside the opening, and a first groove is formed on the first stepped surface, recessed towards the first main surface and extending along the side surface. In the above embodiment, the first groove extending along the side surface of the housing is formed on the second main surface (first stepped surface). Therefore, it is easy to ensure the surface 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 sufficient surface distance between the connection terminal and the heat dissipation surface can be reduced. Furthermore, a first groove is formed on the first step surface of the second main surface of the housing, which is recessed relative to the base surface towards the first main surface. Therefore, for example, in a structure where the base surface and the cooler are separated by a heat-conducting material, the possibility of heat-conducting material entering the first groove can be reduced compared to a structure where the first groove is formed on the base surface. Thus, insufficient heat-conducting material between the base surface and the cooler can be suppressed.

[0129] In a specific example of Method 1 (Method 2), a second groove parallel to the first groove is formed on the first stepped surface. In the above methods, both the first groove and the second groove are formed on the first stepped surface of the housing. Therefore, compared to a structure where only the first groove is formed on the first stepped surface, it is easier to ensure the surface distance between the connecting 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 sufficient surface distance between the connecting terminal and the heat dissipation surface can be reduced.

[0130] In a specific example of Method 2 (Method 3), the first groove is shallower than the second groove. In the above methods, the depths of the first groove and the second groove are different. Therefore, compared to a structure where the first and second grooves are defined to the same depth, it is easier to ensure both the mechanical strength of the housing and the surface distance between the connecting terminals and the heat dissipation surface.

[0131] In a specific example of Method 1 (Method 4), the second main surface further includes a second stepped surface, which, when viewed from above, is located between the first stepped surface and the side surface, recessed relative to the first stepped surface towards the first main surface. A second groove is formed on the second stepped surface, recessed towards the first main surface and extending along the side surface. In the above methods, in addition to the first groove formed on the first stepped surface, a second groove is also formed on the second stepped surface recessed relative to the first stepped surface towards the first main surface. Therefore, compared to structures with only a first groove, or structures with both a first groove and a second groove formed on the first stepped surface, it is easier to ensure the surface 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 sufficient surface distance between the connection terminal and the heat dissipation surface can be reduced.

[0132] In a specific example (method 5) of any of methods 2 to 4, at least one of the first groove and the second groove includes a plurality of portions arranged at intervals from each other along the extending direction of the side. According to the above method, compared to a structure where the first and second grooves are continuous along the entire length of the storage body, it is easier to ensure the mechanical strength of the storage body.

[0133] In a specific example (method 6) of any of methods 1 to 5, the distance (e.g., height difference) between the base surface and the first step surface is 1 mm or more. According to the above method, compared with a structure where the distance between the base surface and the first step surface is less than 1 mm, the aforementioned effect of ensuring the surface distance between the connecting terminal and the surface of the cooler is particularly significant.

[0134] In a specific example (method 7) of any of methods 1 to 6, the first groove includes a plurality of portions arranged at intervals from each other along the extending direction of the side. According to the above method, compared to a structure where the first groove is continuous along the entire length of the storage body, it is easier to ensure the mechanical strength of the storage body.

[0135] In a specific example (method 8) of any of methods 1 to 7, the first groove is formed separately from the connecting surface between the base surface and the first step surface. In the above methods, the first groove is formed separately from the connecting surface. Therefore, compared to a structure where the inner wall surface of the first groove is continuous with the connecting surface, it is easier to ensure the surface distance between the connecting 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 sufficient surface distance between the connecting terminal and the heat dissipation surface can be reduced.

[0136] In a specific example (method 9) of any of methods 1 to 7, the inner wall surface of the first groove is continuous with the connecting surface between the base surface and the first step surface. In the above methods, the inner wall surface of the first groove is continuous with the connecting surface. Therefore, compared with a structure where the first groove is separated from the connecting surface, changes in the shape of the second main surface of the housing are suppressed. Therefore, stress concentration on the second main surface of the housing can be suppressed.

[0137] In a specific example (method 10) of any of methods 1 to 9, the first groove is continuous along the entire length of the housing along the extension direction of the side surface. According to the above method, since the first groove is continuous along the entire length of the housing, it is easy to ensure the surface distance between the connecting terminal 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 ensure sufficient surface distance between the connecting terminal and the heat dissipation surface can be reduced.

[0138] In a specific example (method 11) of any of methods 1 to 10, the semiconductor module further includes an auxiliary terminal. The side includes: a first side from which the connection terminal protrudes; and a second side intersecting the first side, from which the auxiliary terminal protrudes. The first groove includes: a first portion extending along the extension direction of the first side; and a second portion continuous with the first portion extending along the extension direction of the second side. In the above methods, the first groove includes a first portion extending along the extension direction of the first side from which the connection terminal protrudes and a second portion extending along the second side from which the auxiliary terminal protrudes. Therefore, in addition to easily ensuring the surface distance between the connection terminal and the heat dissipation surface, it is also easy to ensure the surface 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 ensure sufficient surface distance between the auxiliary terminal and the heat dissipation surface can be reduced. Furthermore, sides 13a and 13b in the above methods are examples of the "first side" of method 11, and sides 13c and 13d are examples of the "second side" of method 11.

[0139] In a specific example (method 12) of any of methods 1 to 11, a plurality of connecting terminals including the connecting terminals protrude from the side. Between adjacent connecting terminals among the plurality of connecting terminals, a plurality of side grooves extending in a direction from the first main surface toward the second main surface are formed on the side. The first groove is continuous in the housing within a second range corresponding to a first range of the plurality of side grooves arranged in the direction of extension of the side. In the above method, since side grooves are formed on the side of the housing, the surface distance between adjacent connecting terminals is easily ensured. In addition, since the first groove is continuous throughout the range of the plurality of side grooves arranged in the housing, the surface distance between each connecting terminal and the heat dissipation surface is also easily ensured. In other words, the height of the housing (distance between the first main surface and the base surface) required to ensure sufficient surface distance between the connecting terminals and the heat dissipation surface can be reduced.

[0140] In a specific example (method 13) of any of methods 1 to 12, 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 connecting terminal has a portion of a connecting lead electrically connected to the main electrode of the semiconductor chip protruding from the first side surface. The second main surface also includes a second stepped surface, which, when viewed from above, is located between the base surface and the third side surface and is recessed relative to the base surface towards the first main surface. The first stepped surface is the portion located between the base surface and the first side surface and recessed relative to the base surface towards the first main surface when viewed from above. No groove is formed on the second stepped surface. For the first stepped surface of the housing, since a connecting terminal electrically connected to the main electrode of the semiconductor chip is provided, ensuring sufficient surface clearance between the connecting terminal and the heat dissipation surface is particularly important. According to method 13, since a first groove is formed on the first stepped surface, it is easy to ensure surface clearance between the connecting terminal and the heat dissipation surface. On the other hand, the second stepped surface in the second main surface, located between the base surface and the third side surface, is a flat surface without a groove. Therefore, the second stepped surface has the advantage of easily maintaining mechanical strength. Furthermore, side 13a of each of the above methods is an example of the "first side" of method 13, and side 13b is an example of the "third side" of method 13.

[0141] One aspect (aspect 14) of this disclosure provides a semiconductor module comprising: a housing including a first main surface and a second main surface facing opposite directions, and 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 within 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. The second main surface includes: a base surface having an opening; a first stepped surface, which, when viewed from above, is located between the base surface and the first side surface and is recessed relative to the base surface towards the first main surface; and a second stepped surface, which, when viewed from above, is located between the base surface and the third side surface and is recessed relative to the base surface towards the first main surface. The mounting substrate includes a heat dissipation surface located inside the opening. A first groove is formed on the first stepped surface, recessed towards the first main surface and extending along the direction of the first side surface. A second groove is formed on the second stepped surface, recessed towards the first main surface and extending along the direction of the third side surface. In the above-described manner, since the first groove and the second groove are formed on the second main surface (first step surface, second step surface), it is easy to ensure the surface distance between the first connecting terminal and the second connecting 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 sufficient surface distance between the first connecting terminal and the second connecting terminal and the heat dissipation surface can be reduced. Furthermore, the first groove and the second groove are formed on the step surface (first step surface, second step surface) of the second main surface of the housing, which is recessed relative to the base surface on the side of the first main surface. Therefore, for example, in a structure where the base surface and the cooler are separated by a heat-conducting material, the possibility of heat-conducting material entering the first groove or the second groove can be reduced compared to a structure where the first groove and the second groove are formed on the base surface. Therefore, the insufficiency of heat-conducting material between the base surface and the cooler can be suppressed. In addition, the side surface 13a of each of the above-described manner is an example of the "first side surface" of manner 14, and the side surface 13b is an example of the "third side surface" of manner 14.

Claims

1. A semiconductor module, wherein, This semiconductor module has the following features: The storage body includes a first main surface and a second main surface facing opposite directions to each other, and a side surface between the first main surface and the second main surface; The mounting base is housed within the housing. A semiconductor chip is mounted on the mounting substrate; as well as A connecting terminal protrudes from the side. The second main face includes: The base surface has an opening; as well as The first step surface, when viewed from above, is located between the base surface and the side surface, and is recessed relative to the base surface on the first main surface side. The mounting base plate includes a heat dissipation surface located inside the opening. A first groove is formed on the first step surface, which is recessed toward the first main surface and extends along the side surface.

2. The semiconductor module according to claim 1, wherein, A second groove parallel to the first groove is formed on the first step surface.

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

4. The semiconductor module according to claim 1, wherein, The second main surface also includes a second stepped surface, which, when viewed from above, is located between the first stepped surface and the side surface, and is recessed relative to the first stepped surface on the first main surface side. A second groove is formed on the second step surface, which is recessed toward the first main surface and extends along the side surface.

5. The semiconductor module according to any one of claims 2 to 4, wherein, At least one of the first groove and the second groove includes a plurality of portions arranged at intervals from each other along the extension direction of the side.

6. The semiconductor module according to claim 1, wherein, The distance between the base surface and the first step surface is more than 1 mm.

7. The semiconductor module according to claim 1, wherein, The first groove includes a plurality of portions arranged at intervals from each other along the extension direction of the side.

8. The semiconductor module according to claim 1, wherein, The first groove is formed separately from the connection surface between the base surface and the first step surface.

9. The semiconductor module according to claim 1, wherein, The inner wall surface of the first groove is continuous with the connection surface between the base surface and the first step surface.

10. The semiconductor module according to claim 1, wherein, The first groove extends along the entire length of the housing along the side.

11. The semiconductor module according to claim 1, wherein, The semiconductor module also has auxiliary terminals. The side includes: A first side, from which the connecting terminal protrudes; and The second side intersects with the first side. The auxiliary terminal protrudes from the second side. The first slot includes: The first part extends along the direction of extension of the first side; and The second part is continuous with the first part and extends along the extension direction of the second side.

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

13. The semiconductor module according to claim 1, wherein, The side surface includes a first side surface and a third side surface that face opposite directions to each other between the first main surface and the second main surface. The connection terminal has a portion of a connection lead that protrudes from the first side and is electrically connected to the main electrode of the semiconductor chip. The second main surface also includes a second stepped surface, which, when viewed from above, is located between the base surface and the third side surface, and is recessed relative to the base surface towards the first main surface. The first stepped surface is the portion located between the base surface and the first side surface, and recessed relative to the base surface towards the first main surface, when viewed from above. No groove is formed on the second step surface.

14. A semiconductor module, wherein, This semiconductor module has the following features: A storage body includes a first main surface and a second main surface facing opposite directions to each other, and a first side surface and a third side surface facing opposite directions to each other between the first main surface and the second main surface; The mounting base is housed within the housing. A semiconductor chip is mounted on the mounting substrate; A first connecting terminal protrudes from the first side; as well as The second connecting terminal protrudes from the third side. The second main face includes: The base surface has an opening; A first stepped surface, which, when viewed from above, is located between the base surface and the first side surface, and is recessed relative to the base surface towards the first main surface; and The second step surface, when viewed from above, is located between the base surface and the third side surface, and is recessed relative to the base surface towards the first main surface. The mounting base plate includes a heat dissipation surface located inside the opening. A first groove is formed on the first step surface, which is recessed towards the first main surface and extends along the first side surface. A second groove is formed on the second step surface, which is recessed toward the first main surface and extends along the direction of the third side surface.

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