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 plate-shaped bonding portion (40) bonded to the upper surface of the semiconductor element via a bonding material (S3), the semiconductor module (1) has a plurality of roughened recesses (45) for roughening the upper surface of the bonding portion, and each of the plurality of roughened recesses has a hexagonal shape in plan view.

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 plate-shaped joint portion which is joined to the upper surface of the semiconductor element via a joining material, the semiconductor module having a plurality of roughened recesses for roughening the upper surface of the joint portion, each of the plurality of roughened recesses being hexagonal in a top view.

[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 2 Yes Figure 1The 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 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.

[0028] Figure 5 This is an equivalent circuit diagram of the semiconductor device according to this embodiment.

[0029] Figure 6 Observe from the direction of arrow B Figure 3 A top view of the first joint portion of the metal wiring plate shown in FIG.

[0030] Figure 7 It is along Figure 6 A cross-sectional view taken along the CC line.

[0031] Figure 8 yes Figure 6 Magnified view of part D.

[0032] Fig. 9 yes Figure 6 Magnified view of part D.

[0033] Fig.10 It is a plan view showing a first modified example of the roughened recessed portion provided in the first joining portion of the metal wiring plate.

[0034] Fig.11 It is a plan view showing a second modified example of the roughened recessed portion provided in the first joining portion of the metal wiring plate. DETAILED DESCRIPTION

[0035] The following describes a semiconductor module and a semiconductor device to which the present invention can be applied. Figures 1 to 5 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 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 5 : 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] Semiconductor module 1 is configured by arranging multilayer substrate 2 , semiconductor element 3 , metal wiring plate 4 and the like in casing 11 .

[0040] 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.

[0041] 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).

[0042] 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.

[0043] 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.

[0044] 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 4 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.

[0045] 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).

[0046] 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.

[0047] 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.

[0048] 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).

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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 4 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 4 As shown, they may be arranged in an obliquely offset manner.

[0053] The first bonding portion 40 is formed in a rectangular shape smaller than the outer shape of the semiconductor element 3 in a plan view, 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 bonding portion 40 on the positive side in the X direction (on the connecting portion 42 side), and the first bent portion 43 is bent at a substantially right angle and stands upward. One end (left end) of the connecting portion 42 is connected to the upper end of the first bent portion 43.

[0054] The second joint portion 41 is formed in a rectangular shape smaller than the outer shape of the circuit board 22 in a plan view, 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 joint portion 41 on the negative side in the X direction (the connecting portion 42 side), and the second bent portion 44 is bent at a substantially right angle and stands upward. The other end (right end) of the connecting portion 42 is connected to the upper end of the second bent portion 44.

[0055] 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 .

[0056] 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.

[0057] 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 4 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 5 The inverter circuit is shown.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] In addition, if Figure 4 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 4 In 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.

[0062] As described above, in this embodiment, semiconductor element 3, metal wiring plate 4, main terminal 60, etc. form a Figure 5 The inverter circuit shown in FIG. These main terminals 60 (N terminal, P terminal, M terminal) each correspond to Figure 5IN(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).

[0063] 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.

[0064] In addition, in the semiconductor module, it is sought to prevent the peeling from progressing along the interface between the metal wiring board and the sealing resin. As a method of reducing the peeling, for example, it is considered to increase the surface area of ​​the metal wiring board to improve the adhesion between the metal wiring board and the sealing resin (anchor effect). As a method of increasing the surface area of ​​the metal wiring board, a method of forming a concave-convex shape on the surface of the metal wiring board to roughen its surface can be cited.

[0065] In this embodiment, in a structure in which roughened recesses are provided on the upper surface of a metal wiring board to roughen its surface, the arrangement density of a plurality of roughened recesses is increased, and peeling of the sealing resin relative to the metal wiring board is difficult to proceed, thereby improving the anchoring effect compared with the conventional structure.

[0066] Specifically, in the present embodiment, the upper surface of first bonding portion 40 of metal wiring plate 4 constituting semiconductor module 1 is subjected to surface roughening. Figure 6 Observe from the direction of arrow B Figure 3 1 is a plan view of first joining portion 40 of metal wiring plate 4 shown. Figure 7 It is along Figure 6 A cross-sectional view taken along the CC line. Figure 8 and Fig. 9 yes Figure 6 Magnified view of part D.

[0067] like Figure 6As shown, the first joining portion 40, which is rectangular in shape when viewed from above, 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 between 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 a side outer edge 40d extending in the X direction and connecting the two ends of the top outer edge 40a and the boundary portion 40b. The top outer edge 40a, the boundary portion 40b, the side outer edge 40c, and the side outer edge 40d constitute the outer edge of the first joining portion 40, which is rectangular in shape when viewed from above.

[0068] like Figure 6 As shown, a plurality of roughened recesses 45 are provided on the upper surface of the first joint portion 40 to roughen its surface. Each roughened recess 45 is hexagonal in a plan view. Peeling at the interface between the first joint portion 40 and the sealing resin 5 is likely to occur from the end (outer edge) of the first joint portion 40. The hexagonal roughened recesses 45 are easily arranged at a high density, and the roughened recesses 45 are provided throughout the upper surface of the first joint portion 40, so that the peeling generated at the end of the first joint portion 40 can be suppressed from moving toward the inner area of ​​the first joint portion 40, and the details will be described later.

[0069] like Figure 7 As shown, each roughened concave portion 45 is a concave portion with a bottom having a bottom surface 45a at one end (lower end) in the Z direction and the other end (upper end) in the Z direction opening to the upper surface of the first bonding portion 40. The bottom surface 45a is a regular hexagon, and has six inner wall surfaces 45b extending from the six sides of the bottom surface 45a in the Z direction. In other words, each roughened concave portion 45 is a hexagonal column surrounded by the bottom surface 45a and the six inner wall surfaces 45b. All of the plurality of roughened concave portions 45 have the same shape, size, and depth.

[0070] In addition, if Figure 7 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 .

[0071] By providing a plurality of roughened recessed portions 45, the upper surface of the first bonding portion 40 is roughened and the surface area is increased, thereby improving the adhesion (anchor effect) between the upper surface of the first bonding portion 40 and the sealing resin 5. Figure 7 As shown, it is preferable that sealing resin 5 enters roughened recess 45. This can further enhance the anchoring effect. Therefore, above semiconductor element 3, the peeling of sealing resin 5 on the upper surface of metal wiring plate 4 caused by thermal stress can be suppressed.

[0072] The configuration of the plurality of roughened recessed portions 45 will be described in detail. Figure 8 As shown, the plurality of roughened recesses 45 are arranged so that their respective centers are located on the lattice points Q of the hexagonal lattice (equilateral triangle lattice) when viewed from above, and are in the same direction. Therefore, two adjacent roughened recesses 45 are arranged in a manner that the inner wall surfaces 45b closest to each other are parallel. There is a predetermined interval K between two adjacent roughened recesses 45 (between the inner wall surfaces 45b closest to each other). A plurality of roughened recesses 45 are arranged at equal intervals with the intervals K being equal on the entire upper surface of the first joint 40.

[0073] By using the roughened recessed portions 45 that are hexagonal in plan view, the roughened recessed portions 45 can be arranged at a high density on the upper surface of the first bonding portion 40. In particular, by positioning the center of each roughened recessed portion 45 on a lattice point Q of a hexagonal lattice in plan view, and arranging a plurality of roughened recessed portions 45 in the same orientation, the interval K between the roughened recessed portions 45 can be narrowed, and a plurality of roughened recessed portions 45 can be formed on the upper surface of the first bonding portion 40 with better space utilization. Therefore, compared with the case of using roughened recessed portions that are rectangular in plan view, etc., it is possible to achieve an improvement in the anchoring effect of the surface roughening.

[0074] Furthermore, in this embodiment, not only is the arrangement density of roughened recessed portions 45 high, but also the effect of preventing the progress of peeling of sealing resin 5 with respect to metal wiring plate 4 is excellent for the reasons described below.

[0075] The upper surface of the first bonding portion 40 has a plurality of roughened recessed portion rows composed of a plurality of roughened recessed portions 45 arranged at intervals in a first direction. The first direction refers to a direction in which an arbitrary straight line parallel to the upper surface of the first bonding portion 40 extends. In addition, two adjacent roughened recessed portion rows are arranged so that the positions of the roughened recessed portions 45 are staggered in the first direction, and have a region (overlap region) in which the roughened recessed portions 45 of each other partially overlap in a second direction orthogonal to the first direction.

[0076] Reference Fig. 9 The roughening concave portion array and the overlapping region are described. For example, the X direction is set as the first direction, and the Y direction is set as the second direction. A plurality of roughening concave portions 45 arranged at intervals (intervals K) in the X direction are set as the roughening concave portion array 45X. Fig. 9 In FIG. 1 , a row of roughened recessed portions 45 included in each roughened recessed portion row 45X is enclosed by a two-dot chain line frame. In the roughened recessed portion row 45X, the interval between the centers of the roughened recessed portions 45 arranged in the X direction is referred to as a pitch RX.

[0077] like Fig. 9As shown, two adjacent roughening recessed portion columns 45X in the Y direction are arranged so that the positions of the roughening recessed portions 45 of each other are staggered in the X direction. In more detail, two adjacent roughening recessed portion columns 45X in the Y direction are arranged so that the positions of the roughening recessed portions 45 of each other are staggered by half the distance (half pitch) of the pitch RX each time in the X direction. Thus, two adjacent roughening recessed portion columns 45X can be brought close to each other in the Y direction. Thus, two adjacent roughening recessed portion columns 45X are arranged close to each other in the Y direction in such a way that one roughening recessed portion 45 of one roughening recessed portion column 45X enters between two roughening recessed portions 45 of another roughening recessed portion column 45X. As a result, two adjacent roughening recessed portion columns 45X in the Y direction have an overlapping area Va in which the roughening recessed portions 45 of each other are partially alternately present in the middle area in the Y direction. The overlapping area Va is an elongated area having a predetermined width in the Y direction and extending in the X direction.

[0078] In the formation area of ​​each roughened concave portion row 45X, a plurality of roughened concave portions 45 are arranged in the X direction, so that the peeling of the sealing resin 5 with respect to the metal wiring plate 4 can be suppressed from progressing in the X direction. In addition, there is an overlapping area Va between two adjacent roughened concave portion rows 45X in the Y direction, and in the overlapping area Va, parts of the plurality of roughened concave portions 45 of the two roughened concave portion rows 45X are alternately arranged, so that the peeling of the sealing resin 5 with respect to the metal wiring plate 4 can be suppressed from progressing in the X direction. Therefore, within the target range of the surface roughening of the upper surface of the first bonding portion 40, the roughened concave portions 45 are always arranged on a straight line extending in the X direction that is arbitrarily set, and there is no portion that is a non-roughened area (an area where the roughened concave portions 45 are not formed) as a whole in the X direction.

[0079] Next, a case where the Y direction is set as the first direction and the X direction is set as the second direction is described. A plurality of roughened recessed portions 45 arranged at intervals in the Y direction is set as a roughened recessed portion row 45Y. Fig. 9 In FIG. 1 , a row of roughened recessed portions 45 included in each roughened recessed portion row 45Y is enclosed by a two-dot chain line frame. In the roughened recessed portion row 45Y, the interval between the centers of the roughened recessed portions 45 arranged in the Y direction is referred to as a pitch RY.

[0080] Two roughened concave portion columns 45Y adjacent in the X direction are arranged so that the positions of the roughened concave portions 45 of each other are staggered in the Y direction, and are arranged alternately so that the positions are staggered by a distance (half pitch) of half the pitch RY each time in the Y direction. Thus, two adjacent roughened concave portion columns 45Y can be brought close to each other in the X direction. Thus, two adjacent roughened concave portion columns 45Y are arranged close to each other in the X direction in such a way that one roughened concave portion 45 of one roughened concave portion column 45Y enters between two roughened concave portions 45 of another roughened concave portion column 45Y. As a result, two adjacent roughened concave portion columns 45Y in the X direction have an overlapping region Vb in which the roughened concave portions 45 of each other are partially alternately present in the middle region in the X direction. The overlapping region Vb is an elongated region having a predetermined width in the X direction and extending in the Y direction.

[0081] In the formation area of ​​each roughened concave portion row 45Y, a plurality of roughened concave portions 45 are arranged in the Y direction, so that the peeling of the sealing resin 5 relative to the metal wiring plate 4 can be suppressed from progressing in the Y direction. In addition, there is an overlapping area Vb between two adjacent roughened concave portion rows 45Y in the X direction, and in the overlapping area Vb, parts of the plurality of roughened concave portions 45 of the two roughened concave portion rows 45Y are alternately arranged, so that the peeling of the sealing resin 5 relative to the metal wiring plate 4 can be suppressed from progressing in the Y direction. Therefore, within the target range of the surface roughening of the upper surface of the first bonding portion 40, the roughened concave portions 45 are always arranged on a straight line extending in the Y direction that is arbitrarily set, and there is no portion that is a non-roughened area (an area where the roughened concave portions 45 are not formed) as a whole in the Y direction.

[0082] Moreover, in the present embodiment, the roughened recess 45 is arranged not only on any straight line extending in the X direction and any straight line extending in the Y direction, but also on any straight line extending in a direction intersecting the X direction and the Y direction (inclined direction), and there is no portion in the inclined direction which is a non-roughened area as a whole (an area where the roughened recess 45 is not formed).

[0083] For example, as an example of the tilt direction, in Fig. 9 The inclined direction T1 is shown in FIG. In addition, the direction perpendicular to the inclined direction T1 is set as the perpendicular direction T2. ​​The inclined direction T1 is a direction inclined at 60° (120°) relative to the X direction and at 30° (150°) relative to the Y direction. The case where the inclined direction T1 is set as the first direction and the perpendicular direction T2 is set as the second direction is described. A plurality of roughened recessed portions 45 arranged at intervals in the inclined direction T1 is set as a roughened recessed portion row 45T. Fig. 9In FIG. 1 , one row of roughened recessed portions 45 included in each roughened recessed portion row 45T is enclosed by a two-dot chain line frame. In the roughened recessed portion row 45T, the interval between the centers of the roughened recessed portions 45 arranged in the tilt direction T1 is referred to as a pitch RT.

[0084] The positions of the roughened recessed portions 45 of the two adjacent roughened recessed portions 45T in the orthogonal direction T2 are staggered in the inclined direction T1, and are alternately arranged so that the positions are staggered by half (half pitch) of the pitch RT in the inclined direction T1 each time. Thus, the two adjacent roughened recessed portions 45T can be brought close to each other in the orthogonal direction T2. ​​Thus, the two adjacent roughened recessed portions 45T are arranged close to each other in the orthogonal direction T2 in such a way that one roughened recessed portion 45 of one roughened recessed portion row 45T enters between the two roughened recessed portions 45 of the other roughened recessed portion row 45T. As a result, the two adjacent roughened recessed portions 45T in the orthogonal direction T2 have an overlapping region Vc in which the roughened recessed portions 45 of each other are partially alternately present in the middle region in the orthogonal direction T2. ​​The overlapping region Vc is an elongated region having a predetermined width in the orthogonal direction T2 and extending in the inclined direction T1.

[0085] In the formation area of ​​each roughened concave portion row 45T, a plurality of roughened concave portions 45 are arranged in the oblique direction T1, so that the peeling of the sealing resin 5 relative to the metal wiring plate 4 can be suppressed from progressing in the oblique direction T1. In addition, there is an overlapping area Vc between two adjacent roughened concave portion rows 45T in the orthogonal direction T2, and in the overlapping area Vc, parts of the plurality of roughened concave portions 45 of the two roughened concave portion rows 45T are alternately arranged, so that the peeling of the sealing resin 5 relative to the metal wiring plate 4 can be suppressed from progressing in the oblique direction T1. Therefore, within the target range of the surface roughening of the upper surface of the first bonding portion 40, the roughened concave portions 45 are always arranged on an arbitrarily set straight line extending in the oblique direction T1, and there is no portion that is a non-roughened area (an area where the roughened concave portions 45 are not formed) in the entire oblique direction T1.

[0086] As a direction (first direction) in which the non-roughened region is discontinuous on the upper surface of the first bonding portion 40, Fig. 9 Although the X direction, the Y direction, and the inclined direction T1 are illustrated, in the arrangement structure of the roughened recessed portions 45 of the present embodiment, there is no portion where the non-roughened area is linearly continuous in all directions within the target range of the surface roughening of the upper surface of the first bonding portion 40 .

[0087] For example, although detailed description is omitted, Fig. 9When the orthogonal direction T2 is set as the first direction and the inclined direction T1 is set as the second direction, the same condition as in the above case (overlap of two adjacent roughened recessed portion rows) is satisfied, and the same effect as in the above case can be obtained. That is, within the target range of the surface roughening of the upper surface of the first bonding portion 40, the roughened recessed portion 45 is always arranged on an arbitrarily set straight line extending along the orthogonal direction T2, and there is no portion that is a non-roughened area (an area where the roughened recessed portion 45 is not formed) as a whole in the orthogonal direction T2.

[0088] Therefore, when the sealing resin 5 peels off relative to the metal wiring plate 4 at the end (outer edge) of the first joint 40, there is a roughened recess 45 in any direction from the end toward the inside of the first joint 40, which can prevent the peeling from progressing.

[0089] exist Figures 6 to 9 In the above embodiment, each roughened recessed portion 45 forming a hexagonal shape in a plan view is arranged so that two of the six inner wall surfaces 45b are parallel to the Y direction. Fig.10 and Fig.11 2 shows a modified example in which the roughened recessed portions 45 are arranged in a direction different from this direction.

[0090] Fig.10 In the first modified example shown, each roughened recessed portion 45 forming a hexagonal shape in a plan view is arranged so that two inner wall surfaces 45b of the six inner wall surfaces 45b are parallel to the X direction. In other words, the orientation of each roughened recessed portion 45 is relative to Figure 6 The roughened recessed portions 45 are shown in a configuration in which the orientation is rotated by 90° (270°).

[0091] Fig.11 In the second modified example shown, each roughened recessed portion 45 forming a hexagonal shape in a plan view is arranged so that the six inner wall surfaces 45b are all oriented in a non-parallel direction with respect to the X direction and the Y direction. Specifically, the orientation of each roughened recessed portion 45 is oriented in a non-parallel direction with respect to the X direction. Figure 6 The roughened recessed portions 45 are shown in a configuration in which the orientation is rotated by 45° (135°).

[0092] The first and second variants are the same as the above-described embodiment in that a plurality of roughened recesses 45 can be arranged at a high density on the upper surface of the first joining portion 40, and that there is no portion where a non-roughened region is linearly continuous in the region where the surface is roughened by the plurality of roughened recesses 45 (roughened recesses 45 are always present on any straight line along the upper surface of the first joining portion 40). Therefore, the same effect as the embodiment can be obtained.

[0093] for Fig.11In the second variant shown, the six inner wall surfaces 45b of the roughened recess 45 are not parallel to the top outer edge 40a, the boundary portion 40b, the side outer edge 40c and the side outer edge 40d of the first joining portion 40, and accordingly, there is some deviation in the configuration density of the roughened recess 45 at the outer edge side of the first joining portion 40.

[0094] In contrast, for Figure 6 In the above embodiment shown in the figure, two inner wall surfaces 45b of the six inner wall surfaces 45b of the roughened recessed portion 45 are parallel to the top outer edge 40a and the boundary portion 40b of the first joint portion 40, and the roughened recessed portions 45 are evenly arranged at positions along the side outer edge 40c and the side outer edge 40d. Fig.10 In the first variation shown, two of the six inner wall surfaces 45b of the roughened recessed portion 45 are parallel to the lateral outer edges 40c and 40d of the first joining portion 40, and the roughened recessed portions 45 are evenly arranged along the top outer edge 40a and the boundary portion 40b.

[0095] Therefore, when the first joining portion 40 which is rectangular when viewed from above is set as the object of surface roughening, if the good configuration efficiency of the roughening recessed portion 45 near the end (outer edge) of the first joining portion 40 is considered, it is preferred to configure the plurality of roughening recessed portions 45 with two of the six inner wall surfaces 45b being parallel to the end (outer edge) of the first joining portion 40.

[0096] As described above, according to the structure of the present embodiment and the modified example, it is possible to obtain a good effect of preventing the peeling of the sealing resin 5 on the upper surface of the first joint portion 40 of the metal wiring plate 4, and improve the closeness between the metal wiring plate 4 and the sealing resin 5. The plurality of roughened recessed portions 45 that roughen the upper surface of the first joint portion 40 each have a simple shape such as a hexagon when viewed from above, and therefore have the advantage of being easy to form at low cost on the metal wiring plate 4. For example, the roughened recessed portions 45 can be formed by stamping the metal wiring plate 4.

[0097] Since semiconductor element 3 as a heat source is arranged directly below first bonding portion 40 , the anchoring effect due to the surface roughening of first bonding portion 40 has a great influence. Therefore, it is desirable to provide a plurality of roughened recessed portions 45 on at least the upper surface of first bonding portion 40 in metal wiring plate 4 .

[0098] The portions of metal wiring plate 4 other than first bonding portion 40, namely, connecting portion 42, first bent portion 43, and second bent portion 44, have less influence on the peeling of sealing resin 5 than first bonding portion 40, so the presence or absence of roughened recessed portion 45 can be appropriately selected. For example, by roughening only the surface of first bonding portion 40, the processing cost of metal wiring plate 4 can be reduced. In this case, the surfaces of second bonding portion 41, connecting portion 42, first bent portion 43, and second bent portion 44 are flat, and their surface roughness can be equal to the surface roughness of the lower surface of first bonding portion 40.

[0099] Furthermore, in the above-mentioned embodiment, a plurality of roughened recesses 45 are arranged at equal intervals on the substantially entire upper surface of the first joint portion 40 of the metal wiring plate 4, but a part of the upper surface of the first joint portion 40 may be a non-roughened area without the roughened recesses 45. For example, in the case where a wire is connected to the upper surface of the first joint portion 40, the portion where the wire is connected may be a 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 a non-roughened area. In either case, the roughened recesses 45 can be arranged at a high density around the non-roughened area, and thus the above-mentioned effect of the roughened recesses 45 can be obtained.

[0100] In the above embodiment, the depths of the plurality of roughened recessed portions 45 provided on the upper surface of the first joining portion 40 in the Z direction are the same. By making the depths of the plurality of roughened recessed portions 45 the same, it is easy to perform surface roughening processing and to manage the shape accuracy of the first joining portion 40. However, the depths of the plurality of roughened recessed portions are not limited, and a structure in which roughened recessed portions with different depths are mixed can also be adopted.

[0101] In the above embodiment, the plurality of roughened recessed portions 45 provided on the upper surface of the first bonding portion 40 are all of the same size when viewed from above, but the sizes of some of the roughened recessed portions may be different. Fig.11 In the second modified example shown, a roughened recessed portion having an area smaller than the roughened recessed portion 45 when viewed from above may be arranged in the region near the outer edge along the top outer edge 40a, the boundary portion 40b, the side outer edge 40c, and the side outer edge 40d of the first joining portion 40. Thus, the above-mentioned effect of the roughened recessed portion 45 can be obtained, and the surface roughening can be efficiently performed to the vicinity of the outer edge of the first joining portion 40.

[0102] Furthermore, 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] The characteristic points of the above-mentioned embodiment are summarized below.

[0108] 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 plate-shaped joint portion, the joint portion being joined to the upper surface of the semiconductor element via a joint material, the semiconductor module having a plurality of roughened recesses for roughening the upper surface of the joint portion, each of the plurality of roughened recesses being hexagonal in a plan view.

[0109] Furthermore, the plurality of roughened recessed portions are arranged so that the centers of the respective recessed portions are located at lattice points of a hexagonal lattice formed in a plan view of the bonding portion and in the same direction.

[0110] In addition, the upper surface of the joint portion has a plurality of roughened recessed portion columns composed of a plurality of the roughened recessed portions arranged at intervals in a first direction, and two adjacent columns of the roughened recessed portions are arranged so that the positions of the roughened recessed portions are staggered in the first direction, and have a partially overlapping area of ​​the roughened recessed portions in a second direction orthogonal to the first direction.

[0111] Furthermore, the bonding portion has a rectangular shape in a plan view, and the first direction and the second direction include a direction parallel to an outer edge of the bonding portion and a direction intersecting with an outer edge of the bonding portion.

[0112] Furthermore, the joining portion has a rectangular shape in a plan view, and each of the plurality of roughened recessed portions is arranged such that two inner wall surfaces of six inner wall surfaces forming a hexagon in a plan view are parallel to an outer edge of the joining portion.

[0113] Industrial Applicability

[0114] 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.

[0115] This application is based on Japanese Patent Application No. 2022-177079 filed on November 4, 2022, the contents of which are incorporated herein in their entirety.

[0116] Description of Reference Numerals

[0117] 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 (joint); 40a. top outer edge (outer edge); 40b. boundary (outer edge); 40c. lateral outer edge (outer edge); 40d. lateral outer edge (outer edge); 41. second joint; 42. connecting portion; 43. first bent portion; 44. second bent portion; 45. roughened recess; 45a. bottom surface; 45b. inner wall surface; 45T, roughened recessed portion column; 45X, roughened recessed portion column; 45Y, roughened recessed portion column; 60, main terminal; 61, control terminal; 100, semiconductor device; F, coating film; S1, bonding material; S2, bonding material; S3, bonding material; S4, bonding material; T1, inclined direction (first direction, second direction); T2, orthogonal direction (first direction, second direction); Va, overlapping area; Vb, overlapping area; Vc, overlapping area; X, X direction (first direction, second direction); Y, Y direction (first direction, second direction).

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 plate-shaped bonding portion bonded to the upper surface of the semiconductor element via a bonding material. The semiconductor module includes a plurality of roughened recessed portions that roughen the upper surface of the bonding portion, and each of the plurality of roughened recessed portions has a hexagonal shape in a plan view.

2. The semiconductor module according to claim 1, wherein: The plurality of roughened recessed portions are arranged so that their respective centers are located at lattice points of a hexagonal lattice of the bonding portion in a plan view and in the same direction.

3. The semiconductor module according to claim 1 or 2, wherein: The upper surface of the bonding portion has a plurality of roughened recessed portion rows composed of a plurality of the roughened recessed portions arranged at intervals in the first direction, Two adjacent roughened recessed portion rows are arranged with the positions of the roughened recessed portions being shifted in the first direction, and have a region where the roughened recessed portions partially overlap in a second direction perpendicular to the first direction.

4. The semiconductor module according to claim 3, wherein: The joint portion is rectangular in shape when viewed from above. The first direction and the second direction include a direction parallel to the outer edge of the bonding portion and a direction intersecting the outer edge of the bonding portion.

5. The semiconductor module according to claim 1 or 2, wherein: The joint portion is rectangular in shape when viewed from above. Each of the plurality of roughened recessed portions is arranged in a direction such that two inner wall surfaces of six inner wall surfaces forming a hexagon in a plan view are parallel to the outer edge of the joining portion.

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