Semiconductor module

Abstract

The purpose of the present invention is to improve adhesion between a bonding portion of a metal wiring board and a sealing resin in a semiconductor module. A semiconductor module (1) is provided with: a laminated substrate (2) in which a plurality of circuit boards (22) are arranged on the upper surface of an insulating plate (20); a semiconductor element (3) disposed on the upper surface of the at least one circuit board; and a metal wiring board (4) disposed on the upper surface of the semiconductor element. The metal wiring board has a first bonding portion (40) that is bonded to the upper surface of the semiconductor element via a bonding material (S3). The first joining portion includes a plate-like portion having an upper surface and a lower surface, and the upper surface of the plate-like portion has at least one groove (50, 53) provided along the outer periphery of the first joining portion.

Description

Technical Field

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

[0002] The semiconductor module has a substrate on which semiconductor elements such as IGBT (Insulated Gate Bipolar Transistor), power MOSFET (Metal Oxide Semiconductor Field Effect Transistor), and FWD (Free Wheeling Diode) are provided, and is used in inverter devices and the like.

[0003] In such semiconductor modules, for example, in Patent Documents 1 to 3, a semiconductor element is arranged on an insulating substrate (also referred to as a laminated substrate), and a metal wiring plate (also referred to as a lead frame) for wiring is arranged on the upper surface electrode of the semiconductor element. The metal wiring plate is formed into a predetermined shape by, for example, stamping a metal plate. One end of the metal wiring plate is electrically bonded to the upper surface electrode via a bonding material such as solder.

[0004] In a semiconductor module, a sealing resin is filled inside a housing member, and an internal structure including a metal wiring board is covered with the sealing resin. In order to improve the adhesion strength of the sealing resin to the metal wiring board, in Patent Document 4, an ant nest-shaped groove whose opening is narrower than the width of the bottom is formed in the metal wiring board, and in Patent Document 5, a plurality of grid-shaped grooves are formed in the metal wiring board.

[0005] Patent Documents 6 to 9 describe forming a plurality of shallow pits on the surface of a metal wiring board and providing protrusions (returning portions, folded portions, hook-shaped portions) on the inner walls of the shallow pits to improve the sealing strength of the sealing resin. As a method of forming such shallow pits, a hole is formed by a first punching process, and a second punching process is performed on the periphery of the hole to deform the hole locally, so that a protrusion protrudes from the inner wall.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2018-088448

[0009] Patent Document 2: Japanese Patent Application Publication No. 2016-139635

[0010] Patent Document 3: Japanese Patent Application Publication No. 2015-176871

[0011] Patent Document 4: Japanese Patent Application Laid-Open No. 6-163773

[0012] Patent Document 5: Japanese Patent Application Publication No. 2021-077718

[0013] Patent Document 6: Japanese Patent Application Laid-Open No. 7-273270

[0014] Patent Document 7: Japanese Patent Application Publication No. 2005-191178

[0015] Patent Document 8: Japanese Patent Application Publication No. 2017-005124

[0016] Patent Document 9: Japanese Patent Application Publication No. 2007-258587 Summary of the invention

[0017] Problem that the invention aims to solve

[0018] In addition, in such semiconductor modules, the power semiconductor element generates heat due to switching operation. In the structure in which the metal wiring plate is soldered to the surface of the power semiconductor element as described above, deformation may occur at the joint portion due to the change of internal stress caused by temperature change. As a result, it is conceivable that the adhesion of the sealing resin to the joint portion of the metal wiring plate is reduced.

[0019] The present invention has been made in view of the above-mentioned situation, and one object of the present invention is to provide a semiconductor module capable of improving the adhesion between a joint portion of a metal wiring plate and a sealing resin.

[0020] Solutions for solving problems

[0021] A semiconductor module according to one technical solution of the present invention comprises: a stacked substrate having a plurality of circuit boards arranged on the upper surface of an insulating plate; a semiconductor element arranged on the upper surface of at least one of the circuit boards; and a metal wiring plate arranged on the upper surface of the semiconductor element, the metal wiring plate having a first bonding portion which is bonded to the upper surface of the semiconductor element via a bonding material, the first bonding portion comprising a plate-like portion having an upper surface and a lower surface, the upper surface of the plate-like portion having at least one groove arranged along the periphery of the first bonding portion.

[0022] Effects of the Invention

[0023] According to the present invention, it is possible to improve the adhesion between the joint portion of the metal wiring plate and the sealing resin in the semiconductor module. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the semiconductor device according to this embodiment as viewed from above.

[0025] Figure 2Yes Figure 1 The semiconductor device shown is a cross-sectional view taken along line AA.

[0026] Figure 3 This is an enlarged view of the metal wiring plate of this embodiment.

[0027] Figure 4 Observe from the direction of arrow B Figure 3 A top view of the metal wiring plate is shown.

[0028] Figure 5 yes Figure 3 An enlarged view of portion C of the metal wiring board is shown.

[0029] Figure 6 It is a plan view showing a specific example of a semiconductor module to which the metal wiring plate according to the present embodiment is applied.

[0030] Figure 7 This is an equivalent circuit diagram of the semiconductor device according to this embodiment.

[0031] Figure 8 It is a plan view showing a first embodiment in which grooves are provided on the surface of a metal wiring plate.

[0032] Fig. 9 It is along Figure 8 A cross-sectional view taken along the DD line.

[0033] Fig.10 It is a plan view showing a second embodiment in which grooves are provided on the surface of a metal wiring plate.

[0034] Fig.11 It is a plan view showing a third embodiment in which grooves are provided on the surface of a metal wiring plate.

[0035] Fig.12 It is a top view showing a fourth embodiment in which grooves are provided on the surface of a metal wiring plate. DETAILED DESCRIPTION

[0036] The following describes a semiconductor module and a semiconductor device to which the present invention can be applied. Figures 1 to 7 The schematic structures of the entire semiconductor module and semiconductor device and the metal wiring plate included in the semiconductor module and the semiconductor device are described. Figure 1 This is a schematic diagram of the semiconductor device according to this embodiment as viewed from above. Figure 2 Yes Figure 1 The semiconductor device shown is a cross-sectional view taken along line AA. Figure 3 This is an enlarged view of the metal wiring plate of this embodiment. Figure 4 Observe from the direction of arrow B Figure 3A top view of the metal wiring plate is shown. Figure 5 yes Figure 3 An enlarged view of portion C of the metal wiring board is shown. Figure 6 It is a plan view showing a specific example of a semiconductor module to which the metal wiring plate according to the present embodiment is applied. Figure 7 : is an equivalent circuit diagram of the semiconductor device of the present embodiment. Here, as the semiconductor element 3, a structure in which an IGBT and an anti-parallel circuit of a FWD are connected in series is used.

[0037] In addition, in the following drawings, the length direction of the semiconductor module (cooler) is defined as the X direction, the width direction of the semiconductor module (cooler) is defined as the Y direction, and the height direction (thickness direction of the substrate) is defined as the Z direction. In addition, the length direction of the semiconductor module represents the direction in which multiple circuit boards are arranged. The X, Y, and Z axes shown in the figure are orthogonal to each other and constitute a right-hand system. In addition, depending on the situation, the X direction is sometimes referred to as the left-right direction, the Y direction is referred to as the front-back direction, and the Z direction is referred to as the up-down direction. These directions (front-back, left-right, up-down, and down-down directions) are terms used for the convenience of explanation, and sometimes the corresponding relationship with the XYZ directions will change depending on the installation posture of the semiconductor module. For example, the heat dissipation surface side (cooler side) of the semiconductor module is referred to as the lower surface side, and the opposite side is referred to as the upper surface side. In addition, in this specification, a top view refers to the situation of observing the upper or lower surface of the semiconductor module from the Z direction. In addition, the aspect ratios and the size relationships of the components in the figures are only represented by schematic diagrams, and therefore may not be consistent. For the convenience of explanation, it is also envisioned that there are situations in which the size relationships of the components are exaggerated.

[0038] The semiconductor device 100 of this embodiment is applied to a power conversion device such as an inverter for an industrial or vehicle-mounted motor. Figure 1 and Figure 2 As shown in FIG. 1 , the semiconductor device 100 is configured by placing the semiconductor module 1 on the upper surface of the cooler 10. The cooler 10 may have any structure with respect to the semiconductor module 1. FIG.

[0039] The cooler 10 is used to release the heat of the semiconductor module 1 to the outside, and has a rectangular parallelepiped shape as a whole. Although not specifically shown in the figure, the cooler 10 is provided with a plurality of heat sinks on the lower surface side of the base plate, and these heat sinks are housed in a water cooling jacket. In addition, the cooler 10 is not limited to this and can be appropriately changed.

[0040] Semiconductor module 1 is configured by arranging multilayer substrate 2 , semiconductor element 3 , metal wiring plate 4 and the like in casing 11 .

[0041] The laminated substrate 2 is composed of, for example, a DCB (Direct Copper Bonding) substrate, an AMB (Active Metal Brazing) substrate, or a metal base substrate. The laminated substrate 2 is formed by laminating an insulating plate 20, a heat sink 21, and a plurality of circuit boards 22, and is formed in a rectangular shape in plan view as a whole.

[0042] Specifically, the insulating plate 20 is formed of a plate-like body having an upper surface and a lower surface, and has a rectangular shape in a plan view that is long in the X direction. The insulating plate 20 can be formed of a ceramic material such as aluminum oxide (Al2O3), aluminum nitride (AlN), silicon nitride (Si3N4), aluminum oxide (Al2O3), and zirconium oxide (ZrO2).

[0043] In addition, the insulating plate 20 can be formed of, for example, a thermosetting resin such as epoxy resin or polyimide resin, or a composite material in which glass or ceramic material is used as a filler in the thermosetting resin. The insulating plate 20 is preferably flexible and can be formed of, for example, a material containing a thermosetting resin. In addition, the insulating plate 20 can also be called an insulating layer or an insulating film.

[0044] The heat sink 21 has a predetermined thickness in the Z direction and has a rectangular shape in a top view that is longer in the Y direction. The heat sink 21 is formed of a metal plate with good thermal conductivity, such as copper or aluminum. The heat sink 21 is arranged on the lower surface of the insulating plate 20. The lower surface of the heat sink 21 is a mounting surface relative to the cooler 10, which is the mounting object of the semiconductor module 1, and also functions as a heat dissipation surface (heat dissipation area) for releasing the heat of the semiconductor module 1. The heat sink 21 is joined to the upper surface of the cooler 10 via a joining material S1 such as solder. The heat sink 21 can also be arranged on the upper surface of the cooler 10 via a thermally conductive material such as thermal grease or a thermally conductive compound.

[0045] The plurality of circuit boards 22 each have a predetermined thickness and are arranged on the upper surface of the insulating plate 20. Each circuit board 22 is formed into an electrically independent island. For example, the circuit boards 22 have a rectangular shape in plan view and are arranged on the insulating plate 20 in a row along the X direction. Figure 1 As shown, the number is limited to two, but can be changed appropriately. Figure 6 As shown, more than three circuit boards 22 may be arranged on the insulating plate 20. In addition, the shape and arrangement position of the circuit board 22 are not limited thereto and can be appropriately changed. These circuit boards 22 are formed of metal plates with good thermal conductivity such as copper and aluminum. The circuit board 22 may also be called a circuit layer or a circuit pattern.

[0046] A semiconductor element 3 is arranged on the upper surface of a predetermined circuit board 22 (circuit board 22 on the negative side in the X direction) via a bonding material S2 such as solder. The semiconductor element 3 is formed into a rectangular shape in a plan view by a semiconductor substrate such as silicon (Si) or silicon carbide (SiC). The semiconductor element 3 may be a power semiconductor element. The semiconductor element 3 uses switching elements such as IGBT (Insulated Gate Bipolar Transistor), power MOSFET (Metal Oxide Semiconductor Field Effect Transistor), and diodes such as FWD (Free Wheeling Diode).

[0047] In the present embodiment, the semiconductor element 3 is formed of an RC (Reverse Conducting)-IGBT element in which the functions of an IGBT (Insulated Gate Bipolar Transistor) element and a FWD (Free Wheeling Diode) element are integrated.

[0048] In addition, the semiconductor element 3 is not limited thereto, and may also be composed of the above-mentioned switch elements, diodes, etc. For example, the IGBT element and the FWD element may also be separately constructed. In addition, as the semiconductor element 3, a RB (Reverse Blocking: reverse blocking)-IGBT or the like having sufficient withstand voltage against the reverse bias may also be used. In addition, the shape, number of configurations, configuration location, etc. of the semiconductor element 3 may be appropriately changed.

[0049] In addition, the semiconductor element 3 has electrodes (not shown) formed on the upper surface and the lower surface, respectively. For example, the electrode on the upper surface side (upper surface electrode) is composed of an emitter electrode (source electrode) or a gate electrode, and the electrode on the lower surface side (lower surface electrode) is composed of a collector electrode (drain electrode).

[0050] Furthermore, the semiconductor element 3 of the present embodiment is a so-called vertical switching element in which the above-mentioned functional element is formed on a semiconductor substrate, but the present invention is not limited thereto and may be a horizontal switching element.

[0051] A metal wiring plate 4 is disposed on the upper surface of the semiconductor element 3. The metal wiring plate 4 is composed of a plate-like body having an upper surface and a lower surface, and is formed of a metal material such as a copper material, a copper alloy material, an aluminum alloy material, an iron alloy material, etc. The metal wiring plate 4 is formed into a predetermined shape by, for example, stamping. In addition, the shape of the metal wiring plate 4 shown below is only an example, and can be appropriately changed. In addition, the metal wiring plate can also be called a lead frame.

[0052] The metal wiring plate 4 of this embodiment is a long strip extending in the X direction so as to span across a plurality of circuit boards 22 when viewed from above, and has a crank shape formed by bending multiple times when viewed from the side. Figure 2 and Figure 3 As shown, the metal wiring plate 4 is constructed to include: a first joining portion 40, which is joined to the upper surface (upper surface electrode) of the semiconductor element 3 via a joining material S3; a second joining portion 41, which is joined to the upper surface of the circuit board 22 on the positive side of the X direction via a joining material S4; and a connecting portion 42, which connects the first joining portion 40 and the second joining portion 41.

[0053] The width of the metal wiring plate 4 in the Y direction is the same from the first joint portion 40 to the second joint portion 41. In addition, the first joint portion 40, the second joint portion 41 and the connecting portion 42 are arranged in a row along the X direction when viewed from above. In addition, the width of the metal wiring plate 4 in the Y direction does not necessarily have to be the same from the first joint portion 40 to the second joint portion 41. Figure 6 As shown, they may also have different widths. In addition, the first joining portion 40, the second joining portion 41 and the connecting portion 42 are not necessarily arranged in a row. Figure 6 As shown, they may be arranged in an obliquely offset manner.

[0054] The first joining portion 40 is formed into a rectangular shape that is smaller than the outer shape of the semiconductor element 3 when viewed from above, and includes a plate-like portion having an upper surface and a lower surface. A first bent portion 43 is formed at the end of the first joining portion 40 on the positive side of the X direction (the connecting portion 42 side), and the first bent portion 43 is bent at a substantially right angle and stands upright upward. One end (the left end) of the connecting portion 42 is connected to the upper end of the first bent portion 43. A plurality of protrusions 45 protruding toward the semiconductor element 3 are formed on the lower surface of the first joining portion 40, and the details are described later. In addition, a bottomed hole 46 is formed on the upper surface of the first joining portion 40 at a position corresponding to the position directly above the protrusion 45.

[0055] The second joining portion 41 is formed into a rectangular shape that is smaller than the outer shape of the circuit board 22 when viewed from above, and includes a plate-like portion having an upper surface and a lower surface. A second bent portion 44 is formed at the end of the second joining portion 41 on the negative side of the X direction (the connecting portion 42 side), and the second bent portion 44 is bent at a substantially right angle and stands upright upward. The other end (right end) of the connecting portion 42 is connected to the upper end of the second bent portion 44. A plurality of protrusions 47 protruding toward the circuit board 22 are formed on the lower surface of the second joining portion 41, and the details are described later. In addition, a bottomed hole 48 is formed on the upper surface of the second joining portion 41 at a position corresponding to the position directly above the protrusion 47.

[0056] The connecting portion 42 extends in the horizontal direction, and as described above, one end is connected to the first curved portion 43 , and the other end is connected to the second curved portion 44 .

[0057] The length of the first bent portion 43 in the Z direction is shorter than the length of the second bent portion 44 in the Z direction by an amount corresponding to the thickness of the semiconductor element 3. That is, the first bonding portion 40 and the second bonding portion 41 are provided at positions of different heights. More specifically, the first bonding portion 40 is provided at a position higher than the second bonding portion 41.

[0058] In addition, the shape, number, and arrangement position of the metal wiring plate 4 are merely examples and are not limited thereto, and can be appropriately changed. Figure 6 As shown, a plurality of (e.g., four) metal wiring plates 4 may be provided for one semiconductor module, and the details are described later. In addition, in the present embodiment, the semiconductor element 3, the metal wiring plate 4, and the main terminals described later form a semiconductor module. Figure 7 The inverter circuit is shown.

[0059] The stacked substrate 2, the semiconductor element 3 and the metal wiring plate 4 are surrounded by a shell 11. The shell 11 has a cylindrical shape or a frame shape that is a square ring when viewed from above, and is formed of, for example, a synthetic resin. The shell 11 can also be formed of a thermosetting resin material such as epoxy resin, silicone rubber, etc. The lower end of the shell 11 is bonded to the upper surface of the cooler 10 via an adhesive (not shown), and the upper end extends to a position that is sufficiently higher than the upper surface of the metal wiring plate 4. Thus, the shell 11 surrounds the stacked substrate 2, the semiconductor element 3 and the metal wiring plate 4, and defines a space for storing the stacked substrate 2, the semiconductor element 3 and the metal wiring plate 4.

[0060] The internal space defined by case 11 is filled with sealing resin 5. Sealing resin 5 may be filled to the upper surface and reach the upper end of case 11. Thus, laminated substrate 2, semiconductor element 3 and metal wiring plate 4 are sealed. Metal wiring plate 4 is entirely covered with sealing resin 5.

[0061] The sealing resin 5 may be made of, for example, a thermosetting resin. The sealing resin 5 preferably contains at least one of epoxy, silicone, polyurethane, polyimide, polyamide, and polyamide-imide. From the viewpoint of insulation, heat resistance, and heat dissipation, the sealing resin 5 is preferably, for example, an epoxy resin mixed with a filler.

[0062] In addition, if Figure 6 As shown in the specific example, a plurality of main terminals 60 for main current and a plurality of control terminals 61 for control may be provided in the housing 11. The main terminals 60 are formed of a plate-like elongated body and embedded in the side wall of the housing 11. Figure 6In the embodiment, two main terminals 60 constituting an N terminal and a P terminal are arranged in the X direction on the side wall of the housing 11 located on the negative side in the Y direction. In addition, a main terminal 60 constituting an M terminal is arranged on the side wall of the housing 11 located on the positive side in the Y direction.

[0063] As described above, in this embodiment, semiconductor element 3, metal wiring plate 4, main terminal 60, etc. form a Figure 7 The inverter circuit shown in FIG. These main terminals 60 (N terminal, P terminal, M terminal) each correspond to Figure 7 IN(N) (also called low potential side input terminal or negative terminal), IN(P) (also called high potential side input terminal or positive terminal), OUT(M) (also called output terminal or intermediate terminal).

[0064] In addition, the control terminal 61 is formed of a plate-like long strip and embedded in the side wall of the housing 11 located on the positive side in the Y direction. The control terminal 61 is electrically connected to a predetermined control electrode of the semiconductor element 3 via a wiring member such as a bonding wire. These main terminals 60 and control terminals 61 are formed of metal materials such as copper materials, copper alloy materials, aluminum alloy materials, and iron alloy materials, and have a predetermined electrical conductivity and a predetermined mechanical strength. The shape, number, and arrangement position of the main terminals 60 and control terminals 61 are not limited to these, and can be appropriately changed.

[0065] In addition, in the semiconductor module, it is sought to prevent peeling from progressing along the interface between the metal wiring board and the sealing resin. As a method of reducing peeling, for example, it is considered to increase the surface area of ​​the metal wiring board to improve the closeness between the metal wiring board and the sealing resin (anchor effect). As a method of increasing the surface area of ​​the metal wiring board, it can be cited that a concave-convex shape is formed on the surface of the metal wiring board. However, if the lower surface of the metal wiring board (the surface opposite to the semiconductor element) has a concave-convex shape, it will be easy for the bonding material to produce gaps and shrinkage. As a result, the installation quality of the metal wiring board may be affected.

[0066] In addition, as methods for roughening the surface of the metal wiring plate, laser processing, wet methods based on chemical solutions, etc. can be cited. However, these methods will not only become the main cause of cost increase, but also the lower surface side of the metal wiring plate will be roughened, which will easily cause gaps and shrinkage in the bonding material. In other words, it is difficult to roughen the surface of the metal wiring plate without affecting the quality of the bonding material directly below the metal wiring plate.

[0067] In this embodiment, first joining portion 40 of metal wiring plate 4 is recessed from the upper surface side to provide bottomed hole 46, and protrusion 45 protruding from the lower surface side is provided on the back side of bottomed hole 46. In addition, a plurality of roughened recessed portions 49 smaller than bottomed hole 46 are provided on the upper surface of first joining portion 40.

[0068] The projections 45 are arranged at positions close to the four corners of the rectangular first bonding portion 40 in a plan view. By forming a plurality of projections 45 in this way, the first bonding portion 40 does not tilt relative to the upper surface of the semiconductor element 3 during the bonding process of the metal wiring plate 4. Therefore, the posture of the metal wiring plate 4 (first bonding portion 40) can be stabilized.

[0069] In particular, protrusions 45 are provided on the lower surface of metal wiring plate 4, so that a gap at least corresponding to the height of protrusions 45 can be ensured between first bonding portion 40 and semiconductor element 3. By filling the gap with bonding material S3, the thickness of bonding material S3 can be ensured.

[0070] In addition, a plurality of roughened recesses 49 are formed on the upper surface of the first joint portion 40, thereby roughening the surface. As a result, the surface area of ​​the upper surface of the first joint portion 40 increases, and the adhesion (anchoring effect) between the upper surface of the first joint portion 40 and the sealing resin 5 can be improved. In particular, it is preferred that the sealing resin 5 enters the roughened recesses 49. Thus, a further anchoring effect can be expected. Therefore, above the semiconductor element 3, the peeling progress of the sealing resin 5 at the upper surface of the metal wiring plate 4 caused by thermal stress can be suppressed.

[0071] In addition, the second bonding portion 41 is recessed from the upper surface side to provide a bottomed hole 48, and a protrusion 47 protruding from the lower surface side is provided on the back side of the bottomed hole 48. Thus, a gap of at least an amount corresponding to the height of the protrusion 47 can be ensured between the second bonding portion 41 and the circuit board 22. By filling the gap with the bonding material S4, the thickness of the bonding material S4 can be ensured.

[0072] The projections 45 , the bottomed holes 46 , and the roughened recessed portions 49 in the first joining portion 40 , and the projections 47 and the bottomed holes 48 in the second joining portion 41 are formed by, for example, press working.

[0073] In addition, the plurality of roughened recessed portions 49 may be formed on the upper surface of the second joining portion 41, or may be formed only on the upper surface of the first joining portion 40. That is, the roughened recessed portions 49 may not be formed on the connecting portion 42, the first curved portion 43, and the second curved portion 44 that constitute the portion other than the first joining portion 40.

[0074] Since the semiconductor element 3 as a heat source is arranged directly below the first joint portion 40, it can be easily affected by the anchoring effect of the surface roughening. In addition, by roughening only the surface of the portion where the anchoring effect should be improved, there is no need to spend extra processing costs. That is, it can be said that the second joint portion 41, the connecting portion 42, the first bent portion 43 and the second bent portion 44 have less effect on the peeling of the sealing resin 5 than the first joint portion 40. In this case, the surfaces of the second joint portion 41, the connecting portion 42, the first bent portion 43 and the second bent portion 44 are flat, and their surface roughness can be equal to the surface roughness of the lower surface of the first joint portion 40.

[0075] In addition, the lower surface of the first joining portion 40 is preferably a flat surface except for the protrusion 45. That is, it is preferred that the roughened recessed portion 49 is not formed on the lower surface of the first joining portion 40. For example, the surface roughness of the lower surface of the first joining portion 40 is preferably smaller than the surface roughness of the upper surface of the first joining portion 40. By making the lower surface of the first joining portion 40 flat, it is not easy to generate gaps and shrinkage in the joining material S3.

[0076] In addition, if Figure 5 As shown, a coating film F may be interposed at the interface between the upper surface of the first bonding portion 40 and the sealing resin 5 .

[0077] Next, refer to Figures 8 to 12 An embodiment in which a groove is provided on the upper surface of the first joining portion 40 will be described. Figure 8 and Fig. 9 This is the first implementation mode. Fig.10 In the second embodiment, Fig.11 This is the third implementation mode. Fig.12 This is the fourth embodiment. In each embodiment, the upper surface of the first bonding portion 40 has a roughened region whose surface is roughened by a plurality of roughened recesses 49 and a non-roughened region where no roughened recesses 49 are formed. The non-roughened region includes four bottomed holes 46 .

[0078] In the first to fourth embodiments, at least one groove along the outer periphery of the first joining portion 40 is provided on the upper surface of the first joining portion 40. “Along the outer periphery” means that the groove is provided near the outer edge of the first joining portion 40 and extends in a direction substantially the same as the outer edge of the first joining portion 40. In addition, the “groove” means a strip-like shape that is at least longer than the roughened recessed portion 49.

[0079] exist Figure 8 and Fig. 9 In the first embodiment shown, a rectangular frame-shaped groove 50 is provided on the upper surface of the first joining portion 40. The groove 50 is arranged so as to surround the outer sides of all the bottomed holes 46 and all the roughened recessed portions 49.

[0080] Specifically, the first joining portion 40 of a rectangular shape in a top view has a top outer edge 40a on the top side (the end opposite to the connecting portion 42) in the X direction, and has a boundary portion 40b that becomes the boundary with the first curved portion 43 at the end opposite to the top outer edge 40a in the X direction. The top outer edge 40a and the boundary portion 40b are each in a straight line shape extending in the Y direction. In addition, the first joining portion 40 has a pair of side outer edges 40c and 40d that extend in the X direction and connect the top outer edge 40a and the two ends of the boundary portion 40b.

[0081] The groove 50 includes a pair of straight-line portions 50a and 50b extending in the Y direction along the top outer edge 40a and the boundary portion 40b, and a pair of straight-line portions 50c and 50d extending in the X direction along the pair of side outer edges 40c and 40d. There is a predetermined interval in the X direction between the top outer edge 40a and the straight-line portion 50a, and between the boundary portion 40b and the straight-line portion 50b. There is a predetermined interval in the Y direction between the side outer edge 40c and the straight-line portion 50c, and between the side outer edge 40d and the straight-line portion 50d. At a position closer to the outer periphery than the groove 50, the upper surface of the first joint 40 is flat.

[0082] Fig. 9 The first joint portion 40 is shown along Figure 8 The cross-sectional structure at the position of the DD line of the first bonding part 40. The upper surface of the first bonding part 40 is covered with the sealing resin 5, and a coating film F is interposed at the interface between the upper surface of the first bonding part 40 and the sealing resin 5. The peeling at the interface between the first bonding part 40 and the sealing resin 5 is likely to occur from the outer peripheral portion of the first bonding part 40, and the peeling occurring at the outer peripheral portion of the first bonding part 40 proceeds toward the inner region of the first bonding part 40.

[0083] In the structure of metal wiring plate 4, thermal deformation (expansion, contraction) is performed around the rising parts such as first bent part 43 and second bent part 44 in connecting part 42. Therefore, when thermal deformation occurs, the displacement amount of the top side where top outer edge 40a is located in first joint part 40 becomes large. Therefore, in first joint part 40, there is a tendency that peeling tends to progress from top outer edge 40a toward connecting part 42 in the X direction. In particular, in Fig. 9 At the cross-sectional position shown, a non-roughened region without the roughened recessed portion 49 continues on the extension line from the top outer edge 40 a in the X direction, which creates a condition that the peeling easily proceeds toward the inside of the first bonding portion 40 .

[0084] Here, by providing the groove 50, the surface area of ​​the first joint part 40 is increased in the region along the outer periphery of the first joint part 40 which is likely to become the starting point of peeling, and the closeness (anchor effect) between the upper surface of the first joint part 40 and the sealing resin 5 can be improved. As a difference from the plurality of roughened recessed portions 49 arranged at intervals in the X direction and the Y direction on the upper surface of the first joint part 40, the groove 50 is a shape that is continuous in the X direction and the Y direction. Therefore, the groove 50 is present in any part along the outer periphery of the first joint part 40, and a smooth surface can be prevented from continuing from the outer periphery side to the inner periphery side of the first joint part 40.

[0085] For example, in the case where peeling progresses from the top outer edge 40a of the first joint 40 in the X direction, the straight portion 50a of the groove 50 extends in the direction (Y direction) orthogonal to the direction (X direction) of peeling. According to this structure, the straight portion 50a of the groove 50 can be used to suppress the progress of peeling in the X direction. In addition, a roughened area having a roughened recess 49 is provided on the inner side of the groove 50, and an anchoring effect based on the roughened recess 49 can also be obtained. Even in Fig. 9 Since the linear portion 50a of the groove 50 is continuously formed along the distal outer edge 40a of the first bonding portion 40 in the non-roughened region shown in the cross-sectional position, the groove 50 can also suppress the progress of peeling from the distal outer edge 40a in the X direction.

[0086] exist Fig. 9 , the linear portion 50a along the top outer edge 40a of the groove 50 is shown, but not only the linear portion 50a, but also the other linear portions 50b, 50c, and 50d can obtain the effect of suppressing the progress of peeling of the sealing resin 5 from the outer peripheral side of the first bonding portion 40. For example, the linear portions 50c and 50d can suppress the progress of peeling from the side outer edges 40c and 40d in the Y direction. In addition, the linear portion 50b can suppress the progress of peeling from the boundary portion 40b with the first curved portion 43 in the X direction.

[0087] like Fig. 9 As shown, groove 50 is a bottomed groove having a U-shaped (rectangular) cross-sectional shape that opens toward the upper surface of first bonding portion 40. From the viewpoint of ensuring the strength of metal wiring plate 4 and preventing deformation, depth Z1 of groove 50 is preferably 30% or less of thickness T1 of first bonding portion 40. In addition, opening width W1 of groove 50 is preferably 50 μm or more and 600 μm or less.

[0088] In order to stabilize the posture of metal wiring plate 4, projections 45 are provided at the positions near the four corners of the lower surface of first bonding portion 40, and bottomed holes 46 (non-roughened areas) formed at the positions corresponding to the positions just above projections 45 are arranged at the positions near the four corners of the upper surface of first bonding portion 40. Even near the four corners of first bonding portion 40 where surface roughening by roughened recesses 49 is difficult, by arranging one or more rows of grooves 50 at the portion on the outer peripheral side of bottomed holes 46 as the non-roughened area, it is possible to suppress the peeling from progressing to the position of bottomed holes 46 by using grooves 50.

[0089] The cross-sectional shape of the groove 50 may be a shape other than the Japanese character U-shape. For example, the groove 50 may be formed in a cross-sectional shape such as a letter U shape or a semicircle.

[0090] exist Fig.10 In the second embodiment shown, in addition to the groove 50 along the outer periphery of the first joint portion 40, there is also a second groove 51 as another groove located at a position closer to the inner side of the upper surface of the first joint portion 40 than the groove 50. The second groove 51 is a rectangular frame-shaped groove similar to the groove 50, and is composed of a pair of straight-line portions 51a and 51b extending in the Y direction and a pair of straight-line portions 51c and 51d extending in the X direction. A plurality of (4) bottomed holes 46 are arranged between the groove 50 and the second groove 51. The inner side of the second groove 51 becomes a roughening area in which a plurality of roughening recesses 49 are arranged.

[0091] Like the roughened recessed portion 49 and the groove 50, the second groove 51 has the effect of increasing the surface area of ​​the first bonding portion 40 and improving the adhesion between the upper surface of the first bonding portion 40 and the sealing resin 5. Even if the sealing resin 5 is peeled off to a position inside the first bonding portion 40 relative to the groove 50, the second groove 51 can suppress the peeling. Since the second groove 51 is continuous in a frame shape, the second groove 51 can reliably suppress the peeling even in the range where the roughened recessed portion 49 does not exist in the X direction and the Y direction.

[0092] exist Fig.11 In the third embodiment shown, in addition to the groove 50 and the second groove 51, there is also a third groove 52 as another groove located at a position closer to the inner side of the upper surface of the first bonding portion 40 than the second groove 51. The third groove 52 is a rectangular frame-shaped groove like the groove 50 and the second groove 51, and is composed of a pair of straight-line portions 52a and 52b extending in the Y direction and a pair of straight-line portions 52c and 52d extending in the X direction. Between the second groove 51 and the third groove 52, a roughening area is formed in which a plurality of roughening recesses 49 are arranged. Moreover, the inner side of the third groove 52 also becomes a roughening area in which a plurality of roughening recesses 49 are arranged.

[0093] Like the roughened recessed portion 49, the groove 50, and the second groove 51, the third groove 52 has the effect of increasing the surface area of ​​the first bonding portion 40 and improving the closeness between the upper surface of the first bonding portion 40 and the sealing resin 5. Assuming that the peeling of the sealing resin 5 advances to a position that is closer to the inner side of the upper surface of the first bonding portion 40 than the groove 50 and the second groove 51, the progress of the peeling can be suppressed by the third groove 52. Since the third groove 52 is continuous in a frame shape, the effect of reliably suppressing the progress of the peeling can be obtained by the third groove 52 even in the range where the roughened recessed portion 49 does not exist in the X direction and the Y direction.

[0094] The groove formed on the upper surface of the first joining portion 40 is not limited to a frame shape like the above-mentioned groove 50 , the second groove 51 , and the third groove 52 . Fig.12 The fourth embodiment shown is a structural example in which a plurality of parallel grooves 53 (53a to 53g) are formed on the upper surface of the first joint portion 40. The grooves 53a to 53g each extend linearly in the Y direction and are arranged at predetermined intervals in the X direction. The grooves 53a to 53g are each formed to be longer than the distance between the two bottomed holes 46 in the Y direction.

[0095] The groove 53a disposed at the position closest to the top end side of the first joint portion 40 among the plurality of grooves 53 is located between the top end outer edge 40a and the bottomed hole 46 (two bottomed holes 46 located near the top end outer edge 40a). The groove 53b disposed at the position closest to the first curved portion 43 is located between the boundary portion 40b and the bottomed hole 46 (two bottomed holes 46 located near the boundary portion 40b). That is, two grooves 53a and 53b are formed at the position closer to the outer peripheral side in the X direction than each bottomed hole 46. Moreover, between the groove 53a and the groove 53b, grooves 53c, 53d, 53e, 53f, and 53g are formed as other grooves located at the inner side of the upper surface of the first joint portion 40 than the grooves 53a and 53b. The grooves 53c to 53g are respectively formed into a roughened area where a plurality of roughened recesses 49 are formed.

[0096] As described above, in the first joint portion 40, the peeling of the sealing resin 5 is likely to progress from the top side having the top outer edge 40a to the X direction. By providing grooves 53a to 53g extending in the orthogonal Y direction toward the X direction in which the peeling progresses, the effect of suppressing the peeling of the sealing resin 5 can be improved. In particular, since the groove 53a is arranged along the top side opposite to the connecting portion 42, the progress of the peeling can be effectively suppressed in the initial stage. In addition, the groove 53a is formed at a position closer to the outer peripheral side (between the top outer edge 40a and the bottomed hole 46) than the bottomed hole 46, so the groove 53a can be used to prevent the peeling from progressing to the bottomed hole 46.

[0097] Figures 8 to 12 The groove 50 , the second groove 51 , the third groove 52 , and the plurality of grooves 53 shown can be formed by, for example, press working or cutting working.

[0098] Furthermore, in the above-mentioned embodiment, the first joint portion 40 of the metal wiring plate 4 has a bottomed hole 46 in the non-roughened area on the upper surface, but the structure of the non-roughened area is not limited to the bottomed hole. For example, in the case where a wire is connected to the upper surface of the metal wiring plate 4, the portion where the wire is connected may also be the non-roughened area. In addition, a protrusion protruding upward from the metal wiring plate 4, a through hole penetrating the upper and lower surfaces of the metal wiring plate 4, etc. may also be applied as the non-roughened area. In either case, the above-mentioned effect can be obtained by configuring one or more rows of grooves at a position closer to the outer periphery than the non-roughened area.

[0099] In addition, the present invention can also be applied to the first joint portion of a metal wiring plate having no non-roughened area such as bottomed hole 46 on the upper surface. In addition, the present invention can also be applied to the first joint portion of a metal wiring plate whose upper surface is not roughened by roughened recess 49 (does not have roughened recess 49).

[0100] As described above, according to this embodiment, the adhesion between the metal wiring plate and the sealing resin can be improved. In addition, the bonding strength between the semiconductor element and the metal wiring plate can be improved while ensuring the thickness of the bonding material.

[0101] Although the present embodiment and the modified examples have been described, the above-described embodiment and the modified examples may be combined in whole or in part as other embodiments.

[0102] In addition, in the above-mentioned embodiment, the number and arrangement positions of the semiconductor elements are not limited to the above-mentioned configurations, and can be changed as appropriate.

[0103] In addition, in the above-mentioned embodiment, the number and layout of the circuit boards are not limited to the above-mentioned configuration, but can be changed as appropriate.

[0104] In the above-described embodiments, the laminate substrate and the semiconductor element are configured to be rectangular or square in plan view, but the present invention is not limited to this configuration and these structures may be configured to be polygonal shapes other than those described above.

[0105] In addition, the present embodiment is not limited to the above-mentioned embodiment and variation, and various changes, substitutions, and variations can be made within the scope of the main purpose of the technical idea. In addition, if the technical idea can be realized in other ways due to technological progress or other derived technologies, the method can also be used for implementation. Therefore, the claims cover all embodiments that can be included in the scope of the technical idea.

[0106] The characteristic points of the above-mentioned embodiment are summarized below.

[0107] The semiconductor module of the above-mentioned embodiment comprises: a stacked substrate having a plurality of circuit boards arranged on the upper surface of an insulating plate; a semiconductor element arranged on the upper surface of at least one of the circuit boards; and a metal wiring plate arranged on the upper surface of the semiconductor element, the metal wiring plate having a first joining portion, the first joining portion being joined to the upper surface of the semiconductor element via a joining material, the first joining portion comprising a plate-like portion having an upper surface and a lower surface, the upper surface of the plate-like portion having at least one groove arranged along the periphery of the first joining portion.

[0108] Furthermore, the upper surface of the plate-shaped portion has a plurality of roughened recessed portions, the plurality of roughened recessed portions being located on the inner side of the grooves and roughening the upper surface.

[0109] Furthermore, the upper surface of the plate-like portion includes a non-roughened region that does not include the roughened recessed portions, and one or more rows of the grooves are arranged on the outer peripheral side of the non-roughened region.

[0110] Furthermore, the semiconductor module includes another groove located on the inner side of the upper surface of the first bonding portion than the groove.

[0111] In addition, the metal wiring plate has: a second joining portion, which is joined to the upper surface of the other circuit board via a joining material; and a connecting portion, which connects the first joining portion and the second joining portion, and the groove is arranged along at least the top end side of the first joining portion opposite to the connecting portion.

[0112] Industrial Applicability

[0113] As described above, the present invention has an effect of improving the adhesion between the joint portion of the metal wiring plate and the sealing resin, and is particularly useful for semiconductor modules for industrial use or electrical equipment.

[0114] This application is based on Japanese Patent Application No. 2022-177076 filed on November 4, 2022, the entire contents of which are incorporated herein by reference.

[0115] Description of Reference Numerals

[0116] 1. Semiconductor module; 2. Laminated substrate; 3. Semiconductor element; 4. Metal wiring board; 5. Sealing resin; 10. Cooler; 11. Housing; 20. Insulating plate; 21. Heat sink; 22. Circuit board; 40. First joint; 41. Second joint; 42. Connecting portion; 43. First bent portion; 44. Second bent portion; 45. Protrusion; 46. Bottom hole (non-roughened area); 47. Protrusion; 48. Bottom hole; 49. Roughened recess; 50. Groove; 51. Second groove; 52. Third groove; 53. Groove; 60. Main terminal; 61. Control terminal; 100. Semiconductor device; F. Coating film; S1. Bonding material; S2. Bonding material; S3. Bonding material; S4. Bonding material; Z1. Depth of groove; W1. Opening width of groove.

Claims

1. A semiconductor module, wherein: The semiconductor module has: A laminate substrate having a plurality of circuit boards arranged on an upper surface of an insulating plate; a semiconductor element disposed on an upper surface of at least one of the circuit boards; and a metal wiring plate disposed on the upper surface of the semiconductor element, The metal wiring plate has a first bonding portion bonded to the upper surface of the semiconductor element via a bonding material. The first joint portion includes a plate-shaped portion having an upper surface and a lower surface. The upper surface of the plate-shaped portion has at least one groove provided along the outer circumference of the first joining portion.

2. The semiconductor module according to claim 1, wherein: The upper surface of the plate-shaped portion has a plurality of roughened recessed portions, the plurality of roughened recessed portions being located inside the grooves and roughening the upper surface.

3. The semiconductor module according to claim 2, wherein: The upper surface of the plate-shaped portion has a non-roughened area, the non-roughened area does not have the roughened recessed portion, One or more rows of the grooves are arranged on the outer peripheral side of the non-roughened region.

4. The semiconductor module according to claim 1 or 2, wherein: The semiconductor module includes another groove located on an inner side of the upper surface of the first bonding portion than the groove.

5. The semiconductor module according to claim 1 or 2, wherein: The metal wiring plate has: a second joint portion joined to an upper surface of another circuit board via a joint material; and a connecting portion connecting the first joint portion and the second joint portion. The groove is arranged along at least a distal end side of the first joining portion opposite to the connecting portion.

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