Semiconductor module and method for manufacturing the same

Abstract

To fix a module on a curved mounting surface.SOLUTION: A semiconductor module (1) has a laminated substrate (2) composed of an insulating plate (20) having an upper surface and a lower surface, a heat sink (21) arranged on a lower surface of the insulating plate, and a plurality of circuit boards (22) arranged on an upper surface of the insulating plate, and semiconductor elements (3, 4) arranged on an upper surface of each circuit board. The plurality of circuit boards is arranged side by side in a predetermined direction in plan view. A lower surface of the heat sink has a plurality of heat dissipation regions separated along a boundary line of adjacent circuit boards and arranged side-by-side in a predetermined direction in a plan view. The insulating plates are curved along the predetermined direction to be convex to one side in a thickness direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a semiconductor module and a method for manufacturing the semiconductor module. [Background technology]

[0002] 2. Description of the Related Art Semiconductor modules have substrates on which semiconductor elements such as IGBTs (Insulated Gate Bipolar Transistors), power MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), and FWDs (Free Wheeling Diodes) are mounted, and are used in inverter devices and the like.

[0003] In this type of semiconductor module, for example, in Patent Document 1, a plurality of power modules are arranged in a row on a plate-shaped frame. The plate-shaped frame is made of a metal such as aluminum or copper, which is a material with good thermal conductivity. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2015 / 182301 Summary of the Invention [Problem to be solved by the invention]

[0005] Typically, semiconductor modules, the majority of whose structure is composed of laminates, have a flat plate shape. Therefore, the mounting surface of the semiconductor module is often also flat. However, mounting surfaces are not always flat. For example, there may be cases where a semiconductor module is to be mounted on a curved mounting surface.

[0006] The present invention has been made in view of the above points, and one of its objects is to provide a semiconductor module that can be properly fixed even on a curved mounting surface, and a method for manufacturing the semiconductor module. [Means for solving the problem]

[0007] A semiconductor module according to one embodiment of the present invention comprises a laminated substrate formed by stacking an insulating plate having an upper surface and a lower surface, a heat sink disposed on the lower surface of the insulating plate, and a plurality of circuit boards disposed on the upper surface of the insulating plate, and a semiconductor element disposed on the upper surface of each of the circuit boards, wherein the plurality of circuit boards are arranged side by side in a predetermined direction in a planar view, the lower surface of the heat sink is separated along the boundary line between adjacent circuit boards and has a plurality of heat dissipation regions arranged side by side in the predetermined direction in a planar view, and the insulating plate is curved so as to be convex toward one side in the thickness direction along the predetermined direction.

[0008] In addition, a method for manufacturing a semiconductor module according to one aspect of the present invention includes a laminated substrate preparation process for preparing a laminated substrate by stacking an insulating plate having an upper surface and a lower surface, a plurality of circuit boards arranged in a row in a predetermined direction in a planar view on the upper surface of the insulating plate, and a heat dissipation plate arranged on the lower surface of the insulating plate, the lower surface of which is separated along the boundary line between adjacent circuit boards, and having a plurality of heat dissipation areas arranged in a row in the predetermined direction in a planar view; a chip placement process for placing a semiconductor element on the upper surface of each of the circuit boards; and a bending process for bending the insulating plate so that it is convex on one side in the thickness direction along the predetermined direction. [Effects of the Invention]

[0009] The present invention allows the module to be fixed onto a curved mounting surface. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a plan view of a semiconductor module according to an embodiment of the present invention; [Figure 2] FIG. 2 is a plan view seen through the molding resin of FIG. [Figure 3] 2 is a cross-sectional view taken along a plane parallel to the ZX plane in FIG. 1. [Figure 4] 1 is a schematic diagram showing an example of a circuit configuration of a semiconductor module according to an embodiment of the present invention; [Figure 5] 3 is a schematic diagram showing an example of a step (a laminated substrate preparation step) of the method for manufacturing the semiconductor module according to the present embodiment. FIG. [Figure 6] 3 is a schematic diagram showing an example of a step (chip placement step) of the method for manufacturing the semiconductor module according to the present embodiment. FIG. [Figure 7] 3A to 3C are schematic diagrams showing an example of a step (bonding step) in the method for manufacturing the semiconductor module according to the present embodiment. [Figure 8] 5A to 5C are schematic diagrams illustrating an example of a step (bending step) in the method for manufacturing the semiconductor module according to the present embodiment. [Figure 9] 5A to 5C are schematic diagrams illustrating an example of a step (bending step) in the method for manufacturing the semiconductor module according to the present embodiment. [Figure 10] 3A to 3C are schematic diagrams illustrating an example of a process (molding process) in the method for manufacturing the semiconductor module according to the present embodiment. [Figure 11] 3A to 3C are schematic diagrams illustrating an example of a process (molding process) in the method for manufacturing the semiconductor module according to the present embodiment. [Figure 12] 3A to 3C are schematic diagrams illustrating an example of a process (molding process) in the method for manufacturing the semiconductor module according to the present embodiment. [Figure 13] 3 is a schematic diagram showing an example of a step (terminal molding step) of the manufacturing method of the semiconductor module according to the present embodiment. FIG. [Figure 14] 3 is a schematic diagram showing an example of a process (circuit board placement process) in the method for manufacturing the semiconductor module according to the present embodiment. FIG. [Figure 15] 10A to 10C are schematic diagrams showing variations of a semiconductor module (heat sink) according to a modified example (circuit board mounting process). DETAILED DESCRIPTION OF THE INVENTION

[0011] A semiconductor module to which the present invention can be applied will be described below. Fig. 1 is a plan view of a semiconductor module according to this embodiment. Fig. 2 is a plan view seen through the molding resin of Fig. 1. Fig. 3 is a cross-sectional view taken along a plane parallel to the ZX plane of Fig. 1. Fig. 4 is a schematic diagram showing an example of a circuit configuration of a semiconductor module according to this embodiment. Note that the semiconductor module shown below is merely an example, and is not limited to this and can be modified as appropriate.

[0012] In the following figures, the longitudinal direction of the semiconductor module (cooler) is defined as the X direction, the lateral direction of the semiconductor module (cooler) as the Y direction, and the height direction (thickness direction of the board) as the Z direction. The longitudinal direction of the semiconductor module indicates the direction in which multiple circuit boards are arranged. The X, Y, and Z axes in the figures are perpendicular to each other and form a right-handed system. In some cases, the X direction may be referred to as the left-right direction, the Y direction as the front-rear direction, and the Z direction as the up-down direction. These directions (front-rear, left-right, up-down) are terms used for convenience of explanation, and their correspondence with the X, Y, and Z directions may change depending on the mounting orientation of the semiconductor module. For example, the heat dissipation surface (cooler side) of the semiconductor module is referred to as the bottom side, and the opposite side as the top side. In this specification, a plan view refers to the top or bottom of the semiconductor module as viewed from the Z direction. In this specification, the term "curved" is not limited to a shape composed only of curves, but may also include some straight lines. A "curved" shape may be, for example, a shape made up of multiple straight line segments and multiple curved line segments.

[0013] A semiconductor module 1 according to this embodiment is applied to a power conversion device such as a power control unit for an in-vehicle motor, and is a power semiconductor module that constitutes an inverter circuit (see FIG. 4). As shown in FIGS. 1 to 5, the semiconductor module 1 is configured to include a laminated substrate 2, a plurality of semiconductor elements 3 and 4, and a molded resin 5 that seals them. The semiconductor module 1 is attached, for example, via a thermal compound (not shown), to a mounting surface 11 (see FIG. 3) of a heat sink 10 provided in an in-vehicle compressor. The configuration of the mounting destination of the semiconductor module 1 will be described later.

[0014] In this embodiment, the semiconductor module 1 as a whole forms a three-phase inverter circuit shown in Fig. 4. As shown in Fig. 1, in the semiconductor module 1, the U phase, V phase, and W phase are arranged side by side in this order from the positive side in the X direction.

[0015] The laminated substrate 2 is formed of, for example, a DCB (Direct Copper Bonding) substrate, an AMB (Active Metal Brazing) substrate, or a metal-based substrate. The laminated substrate 2 is formed by laminating an insulating plate 20, a plurality of heat sinks 21, and a plurality of circuit boards 22, and is formed into a rectangular shape as a whole in a plan view.

[0016] Specifically, the insulating plate 20 is formed as a plate-like body having an upper surface and a lower surface, and has a rectangular shape in a plan view elongated in the X direction (see FIG. 2). The thickness of the insulating plate 20 may be 0.05 mm or more and 2.0 mm or less. Preferably, the thickness is 0.1 mm or more and 0.5 mm or less. If the insulating plate 20 is too thin, electrical insulation cannot be ensured, and if it is too thick, heat dissipation cannot be ensured. The insulating plate 20 may be formed of a ceramic material such as aluminum oxide (Al2O3), aluminum nitride (AlN), silicon nitride (Si3N4), aluminum oxide (Al2O3) and zirconium oxide (ZrO2). The insulating plate 20 may also be formed of a thermosetting resin such as epoxy resin or polyimide resin, or a composite material using a thermosetting resin with glass or a ceramic material as a filler. The insulating plate 20 is preferably flexible and may be formed of a material containing, for example, a thermosetting resin. The insulating plate 20 may also be called an insulating layer or an insulating film. As will be described in detail later, the insulating plate 20 is bent between each of the circuit boards 22 (five locations) in the cross-sectional view shown in Fig. 3, and has an overall shape that is curved like an arc that is convex upward (in the +Z direction). More specifically, in the cross-sectional view, the insulating plate 20 has alternating linear planar portions (six locations) on which the multiple circuit boards 22 are arranged and bent portions (five locations) that are curved in a direction that is convex upward (in the +Z direction) between each of the circuit boards 22, and has an overall shape that is curved like an arc that is convex upward (in the +Z direction).

[0017] The heat sink 21 has a predetermined thickness and is rectangular in plan view, elongated in the Y direction (see FIG. 2). The thickness of the heat sink 21 may be 0.1 mm or more and 4.0 mm or less, and preferably 0.2 mm or more and 1.0 mm or less. The heat sink 21 is formed of a metal plate with good thermal conductivity, such as copper or aluminum. The heat sink 21 is disposed on the lower surface of the insulating plate 20. In this embodiment, multiple (six) heat sinks 21 are disposed at predetermined intervals. Specifically, as indicated by the dashed line in FIG. 2, they are disposed side by side in the X direction in plan view, and as shown in FIG. 3, they are disposed in an arc-like shape that is convex upward (toward +Z) in cross section as viewed from the Y direction.

[0018] As will be described in detail later, the plurality of heat sinks 21 are arranged corresponding to the plurality of circuit boards 22. The lower surface of the heat sink 21 may be exposed at the lower surface of the semiconductor module 1. More preferably, the lower surface of the heat sink 21 may protrude downward from the lower surface of the molded resin 5. The lower surface of the heat sink 21 is the surface to which the heat sink 10 (see FIG. 3) to which the semiconductor module 1 is attached, and also functions as a heat dissipation surface (heat dissipation area) for dissipating heat from the semiconductor module 1.

[0019] Like the heat sink 21, the circuit board 22 has a predetermined thickness and a rectangular shape in a plan view that is long in the Y direction (see FIG. 2). The thickness of the circuit board 22 may be 0.1 mm or more and 4.0 mm or less, and preferably 0.2 mm or more and 1.0 mm or less. The thickness of the circuit board 22 may be the same as that of the heat sink 21. The circuit board 22 is formed of a metal plate with good thermal conductivity, such as copper or aluminum. The circuit board 22 may also be called a circuit layer or a circuit pattern. The circuit board 22 is disposed on the upper surface of the insulating plate 20. In this embodiment, multiple (six) circuit boards 22 are disposed at predetermined intervals. Specifically, as shown in FIG. 2, the circuit boards 22 are disposed side by side in the X direction in a plan view, and as shown in FIG. 3, in a cross-sectional view taken from the Y direction, the circuit boards 22 are disposed in an arc-like shape that is convex upward (toward the +Z direction) as a whole.

[0020] As will be described in detail later, as shown in Figures 1 and 2, of the six circuit boards 22, the two circuit boards 22 aligned on the positive side in the X direction constitute a U-phase circuit. The two circuit boards 22 aligned in the middle constitute a V-phase circuit. The two circuit boards 22 aligned on the negative side in the X direction constitute a W-phase circuit. In each phase, the circuit board 22 on the positive side in the X direction constitutes an upper arm (which may also be called a high side), and the circuit board 22 on the negative side in the X direction constitutes a lower arm (which may also be called a low side).

[0021] Each of the heat sinks 21 described above is disposed in a location corresponding to (on the opposite side of) each of the circuit boards 22. The corresponding location refers to a location including the area directly below (on the opposite side of) each of the circuit boards 22. Furthermore, it is preferable that the heat sinks 21 have a larger area than the circuit boards 22 in a plan view. More preferably, each of the heat sinks 21 is disposed so as to include the entire area directly below (on the opposite side of) each of the circuit boards 22.

[0022] The gap between adjacent heat sinks 21 is disposed at a location corresponding to the gap between adjacent circuit boards 22 (on the opposite side of insulating plate 20). The corresponding location refers to a location that includes the area directly below the gap between adjacent circuit boards 22 (on the opposite side of insulating plate 20). Furthermore, the gap between adjacent heat sinks 21 preferably has a smaller area than the gap between adjacent circuit boards 22 in a plan view. More preferably, the gap between adjacent heat sinks 21 is disposed so that it is entirely included in the area directly below the gap between adjacent circuit boards 22 (on the opposite side of insulating plate 20).

[0023] A terminal member 23 (first terminal member) constituting wiring for the main current is connected to the end on the negative side in the Y direction of each circuit board 22. Terminal member 23 has an elongated shape extending from the end of circuit board 22 toward the negative side in the Y direction. Each terminal member 23 is formed inside the width (X direction) of each circuit board 22.

[0024] The terminal member 23 on the upper arm side of each phase constitutes a high-potential input terminal (P terminal), while the terminal member 23 on the lower arm side of each phase constitutes an output terminal (U terminal, V terminal, or W terminal) of the corresponding phase.

[0025] An elongated terminal member 24 (second terminal member) is arranged on the negative Y-direction side of the circuit board 22 on the lower arm side of each phase. The terminal member 24 has an elongated shape extending from an end of the circuit board 22 toward the negative Y-direction side. The terminal member 24 is arranged next to the negative X-direction side of the terminal member 23. The terminal members 23 and 24 extend adjacent to each other and parallel to each other along the Y-direction. Each terminal member 24 is formed inside the width (X-direction) of the corresponding circuit board 22. The terminal member 24 constitutes a low-potential input terminal (N terminal).

[0026] Furthermore, a long terminal member 25 (third terminal member) is arranged on the lateral side of the circuit board 22 on the lower arm side of each phase on the positive side in the Y direction. The terminal member 25 extends toward the positive side in the Y direction. Each terminal member 25 is formed inside the width (X direction) of the corresponding circuit board 22. The terminal member 25 constitutes a gate terminal (G terminal). As shown in FIG. 2, the terminal member 25 is arranged on the opposite side of the terminal member 23 across the semiconductor elements 3 and 4 in a plan view.

[0027] Although details will be described later, the above-mentioned multiple circuit boards 22 and multiple terminal members 23, 24, 25 are formed from a single metal plate, and during the manufacturing process, they are connected by a rectangular frame-shaped runner portion 26 (see FIG. 5B). In a later process, runner portion 26 is removed, and the circuit boards 22 and terminal members 23, 24, 25 are separated (cut off). The integrated metal plate may be called a lead frame or a metal wiring board.

[0028] Semiconductor elements 3 and 4 are arranged on the upper surface of each circuit board 22 via a bonding material S such as solder. The semiconductor elements 3 and 4 are arranged side by side in the Y direction. The semiconductor elements 3 and 4 are formed in a rectangular shape in a plan view using a semiconductor substrate made of, for example, silicon (Si) or silicon carbide (SiC). The semiconductor elements may be switching elements such as IGBTs (Insulated Gate Bipolar Transistors) and power MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), or diodes such as FWDs (Free Wheeling Diodes).

[0029] In this embodiment, semiconductor element 3 located on the positive side in the Y direction is composed of an IGBT element, and semiconductor element 4 located on the negative side in the Y direction is composed of an FWD element. Semiconductor elements 3 and 4 may be connected in anti-parallel to each other. Note that in this embodiment, a case where the IGBT element and the FWD element are configured separately has been described, but this is not limiting. As the semiconductor element, an RC (Reverse Conducting)-IGBT in which an IGBT element and an FWD element are integrated, an RB (Reverse Blocking)-IGBT that has sufficient withstand voltage against reverse bias, or the like may also be used.

[0030] The shapes, number, and locations of the semiconductor elements 3 and 4 can be changed as appropriate. The semiconductor elements 3 and 4 in this embodiment are so-called vertical switching elements in which functional elements such as transistors are formed on a semiconductor substrate, but are not limited to this and may be horizontal switching elements.

[0031] The above-described semiconductor elements 3 and 4, circuit board 22, and terminal members 23 and 24 constitute an inverter circuit as shown in Fig. 4. In Fig. 4, IN(P) represents a positive terminal (high potential side input terminal), IN(N) represents a negative terminal (low potential side input terminal), and OUT(U), OUT(V), and OUT(W) represent output terminals for each phase. Also shown is an example in which two semiconductor elements 3 and 4 are connected in anti-parallel.

[0032] The upper surface electrodes of the semiconductor elements 3 and 4 are electrically connected by the wiring member W. The upper surface electrode of the semiconductor element 4 and one end of the terminal member 24 are also electrically connected by the wiring member W. Furthermore, the gate electrode 30 of the semiconductor element 3 and one end of the terminal member 25 are also electrically connected by the wiring member W.

[0033] Conductive wires (bonding wires) are used for these wiring members W. The wires may be made of any one of gold, copper, aluminum, gold alloys, copper alloys, and aluminum alloys, or a combination thereof. Materials other than wires may also be used as wiring members. For example, ribbons may be used as wiring members.

[0034] The laminated substrate 2, the semiconductor elements 3, the terminal members, and the wiring members W are packaged (sealed) with a molded resin 5. As will be described in detail later, the molded resin 5 can be formed by transfer molding. The molded resin 5 may be, for example, a thermosetting resin material such as epoxy resin or silicone rubber, and may further contain glass or a ceramic material as a filler. The molded resin 5 is preferably a flexible material containing, for example, a thermosetting elastomer such as silicone rubber. This makes it easier to arrange the semiconductor module 1 along a heat sink 10 having a cylindrical outer shape, as will be described later.

[0035] In general semiconductor modules, the substrate (laminated substrate) on which the semiconductor elements are mounted is usually flat in consideration of ease of assembly, heat dissipation, etc. Therefore, it is preferable that the location where the semiconductor module is installed is also on a flat surface.

[0036] However, depending on the shape of the structure to which the semiconductor module is to be attached (for example, a compressor or motor in an automobile), it may be necessary to attach the semiconductor module to a curved mounting surface, such as a cylindrical surface. In this case, it is possible to form a flat portion on the structure to which the module is to be attached, but considering the mounting space of the entire device, it is desirable to mount the semiconductor module in a shape that corresponds to the structure to which the module is to be attached without increasing its size. Thus, there is a demand for a semiconductor module with a mounting structure that corresponds to the shape of the structure to which the module is to be attached.

[0037] In the past, it was considered to arrange multiple semiconductor modules on the top surface of a flat heat sink and then curve the heat sink to attach it to the curved surface. However, this structure is specialized for a configuration with multiple semiconductor modules, and it also requires the metal heat sink itself to be curved. For this reason, the conventional structure does not necessarily ensure flexibility in installation, and there is room for improvement.

[0038] Therefore, the present inventors have conceived the present invention to realize a structure in a single semiconductor module that can be curved and installed on a mounting surface. Specifically, in this embodiment, the circuit boards constituting the three-phase inverter circuit are divided into six circuit boards 22 for each upper and lower arm of each phase, and these are arranged side by side in the longitudinal direction (X direction) of a single continuous insulating plate 20. In addition, the heat sink that is normally arranged on the lower surface of insulating plate 20 is also divided into six heat sinks 21 and arranged so as to correspond directly below the six divided circuit boards 22.

[0039] That is, the lower surface of heat sink 21 is separated along boundary line L between adjacent circuit boards 22. More specifically, heat sink 21 is divided into multiple pieces along boundary line L. In this way, the lower surfaces of the multiple divided heat sinks 21 form multiple heat dissipation regions arranged side by side in the X direction in plan view.

[0040] As a result, in the laminated substrate 2 alone, as shown in FIG. 2, the insulating plate 20 is exposed at locations along the boundary line L between adjacent circuit boards 22 or heat sinks 21. That is, no circuit board 22 exists above the boundary line L, and no heat sink 21 exists below the boundary line L. The boundary line L extends in a direction (the lateral direction of the laminated substrate 2, the Y direction) perpendicular to the direction in which the multiple circuit boards 22 are arranged (the longitudinal direction of the laminated substrate 2, the X direction). Therefore, near the boundary line L, the bending rigidity (resistance to bending) of the laminated substrate 2 in the longitudinal direction is adjusted (reduced) to the bending rigidity of one layer of the insulating plate 20, rather than that of three layers (the insulating plate 20, the heat sink 21, and the circuit board 22). Therefore, the laminated substrate 2 (the insulating plate 20) is easily curved starting from the multiple boundary lines L. Therefore, as shown in FIG. 3, the laminated substrate 2 can be molded in a curved state when sealed with molded resin 5.

[0041] Specifically, laminated substrate 2 has circuit board 22, insulating plate 20, and heat sink 21 formed in this order. Insulating plate 20 is formed from a single continuous rectangular plate elongated in the X direction. Circuit board 22 is divided into multiple (six) pieces aligned in the X direction on the upper surface side of insulating plate 20, with multiple (five) gaps aligned in the X direction. Furthermore, heat sink 21 is divided into multiple (six) pieces aligned in the X direction corresponding to circuit board 22 on the lower surface side of the insulating plate, with multiple (five) gaps aligned in the X direction corresponding to the gaps between circuit board 22. Laminated substrate 2 is arranged so that the multiple (five) opposing gaps between heat sink 21 and circuit board 22 are curved, forming an arc shape that is convex upward (towards +Z) as a whole.

[0042] More specifically, the laminated substrate 2 has a flat portion on which at least one of the circuit board 22 and the heat sink 21 is disposed, and a bent portion on which neither the circuit board 22 nor the heat sink 21 is disposed. Each bent portion is bent in a direction that convexes upward (toward +Z). Therefore, the underside of the semiconductor module 1 is curved in an arc shape that convexes upward (toward +Z) as a whole. As a result, the semiconductor module 1 can be disposed along the heat sink 10, which has a cylindrical outer shape and a curved mounting surface 11.

[0043] Furthermore, the area of ​​heat sink 21 in plan view is larger than the area of ​​the corresponding circuit board 22. With this configuration, when semiconductor elements 3 and 4 arranged on circuit board 22 generate heat, heat sink 21 diffuses the heat toward heat sink 10 in accordance with the range of heat diffusion. As a result, the heat from semiconductor elements 3 and 4 can be dissipated effectively.

[0044] In this way, in the semiconductor module 1 according to the present embodiment, by dividing the circuit board 22 and the heat sink 21 for each arm of each phase, it is possible to make it easier to bend the laminated substrate 2 starting from the boundary line L between adjacent arms. As a result, it is possible to obtain a semiconductor module 1 that matches the shape of the curved mounting surface 11, and it is possible to mount the semiconductor module 1 in a space-saving manner.

[0045] Furthermore, in the semiconductor module 1 according to this embodiment, insulating plate 20 is a single continuous piece, which ensures a sufficient creepage distance between circuit board 22 and heat sink 21. This allows the distance between adjacent circuit boards 22 and adjacent heat sinks 21 to be reduced. As a result, a small semiconductor module 1 can be obtained that fits the shape of curved mounting surface 11, making it possible to provide a space-saving semiconductor module 1.

[0046] Next, a method for manufacturing a semiconductor module according to this embodiment will be described with reference to Figures 5 to 13. Figures 5 to 14 are schematic views showing an example of one step in the method for manufacturing a semiconductor module according to this embodiment. Figures 5A, 6A, and 7A are schematic cross-sectional views, and Figures 5B, 6B, and 7B are schematic plan views. Note that the method for manufacturing a semiconductor module shown below is merely an example and is not limited to this configuration, and can be modified as appropriate.

[0047] The manufacturing method of the semiconductor module 1 according to this embodiment includes a laminated substrate preparation process (see FIG. 5), a chip placement process (see FIG. 6), a bonding process (see FIG. 7), a bending process (see FIGS. 8-9), a molding process (see FIGS. 10-12), a terminal molding process (see FIG. 13), and a circuit board placement process (see FIG. 14). The order of these processes may be changed or combined as long as there is no contradiction.

[0048] First, as shown in Figures 5A and 5B, in the laminated substrate preparation process, a laminated substrate 2 is prepared by stacking an insulating plate 20 having an upper surface and a lower surface, a plurality of circuit boards 22 arranged side by side in a predetermined direction (X direction) on the upper surface of the insulating plate 20, and a plurality of heat sinks 21 arranged on the lower surface of the insulating plate 20 at locations corresponding to the plurality of circuit boards 22.

[0049] 5B, the plurality of circuit boards 22 and the plurality of terminal members 23, 24, and 25 are formed from a single metal plate. More specifically, the plurality of circuit boards 22 and the plurality of terminal members 23, 24, and 25 are integrally connected by a rectangular frame-shaped runner portion 26.

[0050] Next, the chip placement process is carried out. As shown in Figures 6A and 6B, in the chip placement process, semiconductor elements 3 and 4 are placed on the upper surface of each circuit board 22. Specifically, one semiconductor element 3 and one semiconductor element 4 are placed on the upper surface of each circuit board 22 with bonding material S interposed therebetween.

[0051] Next, the bonding process is carried out. As shown in FIGS. 7A and 7B, in the bonding process, the upper electrodes of the semiconductor elements 3 and 4 are electrically connected by the wiring member W. The upper electrode of the semiconductor element 4 is also electrically connected to one end of the terminal member 24 by the wiring member W. The gate electrode 30 of the semiconductor element 3 is also electrically connected to one end of the terminal member 25 by the wiring member W. In this case, in the bonding process, it is preferable to bond the wiring member W with a long slack, in anticipation of the laminated substrate 2 being bent in the subsequent bending process. This prevents the wiring member W from becoming taut even after bending, making it possible to prevent breakage.

[0052] Next, a bending process is performed. As shown in FIGS. 8 and 9, the laminated substrate 2 after the chip placement process is placed in molds (lower mold 12 and upper mold 13). The lower mold 12 and the upper mold 13 have a curved recess (concave) that is convex upward. The laminated substrate 2 is pressed against the recess of the lower mold 12 and bent to fit the curved shape of the recess. That is, in the bending process, the laminated substrate 2 (insulating plate 20) is bent along a predetermined direction (X-axis direction) so as to be convex on one side in the thickness direction (Z-axis direction). Note that in this embodiment, the laminated substrate 2 is bent so as to be convex toward the positive side of the Z direction, but this is not limiting and appropriate modifications are possible. For example, the laminated substrate 2 may be curved so as to be convex toward the negative side of the Z direction. Furthermore, the laminated substrate 2 may include both a portion that is curved so as to be convex toward the positive side of the Z direction and a portion that is curved so as to be convex toward the negative side of the Z direction. Alternatively, the laminated substrate 2 may include a convexly curved portion and a flat portion. In addition, although the present embodiment has been described with reference to a case where the laminated substrate 2 is curved in an arc shape, the present invention is not limited to this and can be modified as appropriate. For example, the laminated substrate 2 may be curved in an arc corresponding to a part of an ellipse.

[0053] Next, the molding process is carried out. As shown in FIG. 10, in the molding process, a lower mold 12 and an upper mold 13 are brought close together to form a predetermined closed space within the mold. Then, as shown in FIG. 11, a mold resin 5 is filled into the closed space within the mold, thereby packaging the laminated substrate 2 and the semiconductor elements 3 and 4. This mold resin 5 is formed, for example, by transfer molding. By using transfer molding, there is no need to prepare a dedicated case, and after all the components have been mounted, these components can be sealed and integrated at once. Thereafter, once the mold resin 5 has completely hardened, the lower mold 12 and the upper mold 13 are retracted from each other and opened, and a single semiconductor module 1 with the integrated components can be obtained.

[0054] Next, the terminal molding process is carried out. As shown in Fig. 13, the runner portion 26 (see Figs. 5 to 7) is removed, thereby separating (cutting off) each circuit board 22 and each terminal member 23-25. Furthermore, each terminal member 23-25 ​​is bent at a right angle along bending line B shown in Fig. 13. As a result, each terminal member 23-25 ​​is molded so as to extend toward the positive side in the Z direction.

[0055] Next, a circuit board placement process is carried out. As shown in Fig. 14, in the circuit board placement process, a circuit board 6 (which may also be called a printed circuit board or a control board) is placed on a plurality of terminal members 23-25. Specifically, the circuit board 6 is formed as a printed circuit board that is rectangular in plan view, and through holes (not shown) are formed at locations corresponding to the tips of the plurality of terminal members 23-25. The tips of each terminal member are inserted into the through holes and soldered, thereby electrically connecting the circuit pattern on the circuit board 6 to each terminal member.

[0056] As shown in FIG. 14, a semiconductor device 100 (power conversion device) may be configured by including the semiconductor module 1, a heat sink 10 that constitutes part of a cooler to which the semiconductor module 1 is attached, and a circuit board 6.

[0057] As described above, according to this embodiment, by dividing the circuit board 22 and the heat sink 21 for each arm, it is possible to make the laminated substrate 2 easier to bend, and a semiconductor module 1 that matches the shape of the curved mounting surface 11 can be obtained.

[0058] In the above embodiment, the components of the semiconductor module 1 are sealed by transfer molding, but the present invention is not limited to this. For example, a resin case and metal terminals may be formed separately, various components may be placed inside the case, and the case may be filled with a sealing resin.

[0059] Furthermore, in the above embodiment, six heat sinks 21 are arranged directly below six circuit boards 22, but the present invention is not limited to this configuration. For example, the configuration shown in Fig. 15 may also be used. Fig. 15 is a diagram showing variations of heat sinks according to modified examples.

[0060] In the above embodiment, the heat sink 21 is divided into multiple (six) pieces by the boundary line L. Here, "divided" refers to a state in which adjacent heat sinks 21 are completely separated with a predetermined gap between them. Meanwhile, in a modified example, as shown in FIG. 15A , a thin groove (heat sink 21a) extending in the Y direction may be formed on the lower surface of the insulating plate 20 between two adjacent heat sinks 21. That is, the lower surface of the heat sink 21 may be separated into multiple heat sink areas by the groove formed along the boundary line L so as to leave a predetermined thickness. Here, "separation" does not necessarily mean a state in which the heat sink 21 is completely divided, but also includes a state in which the lower surface heat sink area is divided into multiple pieces while leaving a small thickness of the heat sink 21. The groove may form a heat sink 21a that is thinner than the surrounding heat sinks 21. In this case, it is preferable that the boundary line L between adjacent heat sinks 21 coincides with the boundary line L of the circuit board 22 located directly above. Furthermore, it is preferable that the boundary line L is located at a position overlapping with the groove portion (heat sink 21a) of the heat sink 21. For this reason, the bending rigidity is reduced near the boundary line L. Therefore, the laminated substrate 2 (insulating plate 20) is easily bent starting from the multiple boundary lines L. Furthermore, on the lower surface of the insulating plate 20, another heat sink 21a may be disposed between two adjacent heat sinks 21. In this case, it is preferable that the rigidity (hardness, etc.) of the another heat sink 21a is smaller than that of the heat sink 21. In this case, it is also preferable that the thickness of the heat sink 21a is smaller than that of the heat sink 21. In this way, it is possible to adjust (reduce) the flexibility (bending rigidity) of the laminated substrate 2 as a whole by changing the configuration of the heat sink.

[0061] 15B, heat sinks 27 of the same shape may be arranged offset in the X direction and partially overlap in the Z direction, forming an expandable shutter-like heat sink 27 as a whole. In this case, the boundary line L between adjacent heat sinks 21 may be the shutter portion of the area facing the gap between adjacent circuit boards 22. Also, as shown in FIG. 15C, heat sinks 28 of the same shape may be arranged offset not only in the X direction but also in the Y direction, and connected alternately in the Y direction to form a bendable heat sink. Furthermore, as shown in FIG. 15D, a bendable heat sink like a bamboo blind may be formed by arranging and connecting multiple cylindrical heat sink members 29 that are elongated in the Y direction along the X direction. In this case, the boundary line L between adjacent heat sinks 21 may be in the area facing the gap between adjacent circuit boards 22. 15A to 15D, there is no circuit board 22 on the upper surface of insulating plate 20, and one or more grooves are present in heat sinks 21 (21a), 27 to 29 on the lower surface of insulating plate 20, corresponding to boundary lines L. This reduces bending rigidity in the vicinity of boundary lines L. This makes laminated substrate 2 (insulating plate 20) more likely to bend, starting from the multiple boundary lines L.

[0062] Furthermore, in the above embodiment, the number and locations of the semiconductor elements 3 and 4 are not limited to the above configuration, and can be changed as appropriate.

[0063] Furthermore, in the above embodiment, the number and layout of the circuit boards are not limited to the above configuration, and can be changed as appropriate.

[0064] In the above embodiment, the laminated substrate 2 and the semiconductor elements 3 and 4 are configured to be rectangular or square in plan view, but are not limited to this configuration. These elements may be configured to be polygonal shapes other than those described above.

[0065] Furthermore, although the present embodiment and modifications have been described, other embodiments may be combinations of the above-described embodiments and modifications in whole or in part.

[0066] Furthermore, the present embodiment is not limited to the above-described embodiments and modifications, and may be variously changed, substituted, or modified within the scope of the spirit of the technical idea. Furthermore, if the technical idea can be realized in a different way due to technological advances or derived other technologies, it may be implemented using that method. Therefore, the claims cover all embodiments that may fall within the scope of the technical idea.

[0067] The features of the above embodiment are summarized below. The semiconductor module according to the above embodiment comprises a laminated substrate formed by stacking an insulating plate having an upper surface and a lower surface, a heat sink arranged on the lower surface of the insulating plate, and a plurality of circuit boards arranged on the upper surface of the insulating plate, and a semiconductor element arranged on the upper surface of each of the circuit boards, wherein the plurality of circuit boards are arranged side by side in a predetermined direction in a planar view, the lower surface of the heat sink is separated along the boundary line between adjacent circuit boards, and has a plurality of heat dissipation areas arranged side by side in the predetermined direction in a planar view, and the insulating plate is curved so as to be convex toward one side in the thickness direction along the predetermined direction.

[0068] In addition, in the semiconductor module according to the above embodiment, the heat dissipation areas are arranged at locations corresponding to those directly below the circuit boards, and the insulating plate is curved starting from the boundary line of the adjacent circuit board or the heat dissipation area.

[0069] In the semiconductor module according to the above embodiment, the boundary line extends in a direction intersecting the predetermined direction.

[0070] In the semiconductor module according to the above embodiment, the heat sink is divided into a plurality of pieces along the boundary line.

[0071] In the semiconductor module according to the above embodiment, the lower surface of the heat sink is separated into the plurality of heat dissipation regions by grooves formed along the boundary line so as to leave a predetermined thickness.

[0072] In addition, in the semiconductor module according to the above embodiment, a three-phase inverter circuit is formed by a plurality of the circuit boards and semiconductor elements arranged on the upper surfaces of the circuit boards, and the circuit boards constituting each phase of the three-phase inverter circuit are arranged side by side in the predetermined direction.

[0073] In addition, in the semiconductor module according to the above embodiment, in each phase of the three-phase inverter circuit, the circuit board constituting the upper arm and the circuit board constituting the lower arm are arranged side by side in the predetermined direction.

[0074] In addition, the semiconductor module according to the above embodiment further includes a first terminal member connected to the circuit board and constituting wiring for the main current, the first terminal member being formed of an elongated body extending in a direction intersecting the predetermined direction, and the first terminal members provided on each of the circuit boards being arranged side by side in the predetermined direction.

[0075] In addition, the semiconductor module according to the above embodiment further includes a second terminal member arranged on the side of the circuit board constituting the lower arm, the second terminal member being formed of an elongated body extending in a direction intersecting the predetermined direction and arranged to extend adjacent to and parallel to the first terminal member.

[0076] In addition, the semiconductor module according to the above embodiment further includes a third terminal member arranged on the opposite side of the circuit board from the first terminal member, and the third terminal member is formed of an elongated body extending in a direction intersecting the predetermined direction.

[0077] Furthermore, in the semiconductor module according to the above embodiment, the first terminal member on the upper arm side constitutes a high-potential side input terminal, the first terminal member on the lower arm side constitutes an output terminal for each phase, the second terminal member constitutes a low-potential side input terminal, and the third terminal member constitutes a gate terminal, and the third terminal member is electrically connected to the gate electrode of the semiconductor element.

[0078] In the semiconductor module according to the above embodiment, the area of ​​the heat sink in plan view is larger than the area of ​​the corresponding circuit board.

[0079] In the semiconductor module according to the above embodiment, the heat sink in plan view includes the entire area directly below the corresponding circuit board.

[0080] In addition, the manufacturing method of the semiconductor module according to the above embodiment includes a laminated substrate preparation process for preparing a laminated substrate constructed by stacking an insulating plate having an upper surface and a lower surface, a plurality of circuit boards arranged in a row in a predetermined direction in a planar view on the upper surface of the insulating plate, and a heat dissipation plate arranged on the lower surface of the insulating plate, the lower surface of which is separated along the boundary line of adjacent circuit boards, and which has a plurality of heat dissipation areas arranged in a row in the predetermined direction in a planar view; a chip placement process for placing a semiconductor element on the upper surface of each of the circuit boards; and a bending process for bending the insulating plate so that it is convex on one side in the thickness direction along the predetermined direction.

[0081] Furthermore, the method for manufacturing a semiconductor module according to the above embodiment further includes, after the bending step, a molding step of sealing the laminated substrate and the semiconductor element with a molding resin.

[0082] In addition, the manufacturing method of the semiconductor module according to the above embodiment further includes a terminal molding process in which, in the laminated substrate preparation process, the laminated substrate is composed of a metal wiring board in which a plurality of the circuit boards and a plurality of terminal members are integrally connected via runner portions, and the runner portions are removed to mold the plurality of terminal members.

[0083] Furthermore, the method for manufacturing a semiconductor module according to the above embodiment further includes, after the terminal molding step, a circuit board placement step of placing a circuit board on the plurality of terminal members. [Industrial Applicability]

[0084] As described above, the present invention has the effect of being able to properly fix a semiconductor module even on a curved mounting surface, and is particularly useful for semiconductor modules that are mounted on curved mounting surfaces. [Explanation of symbols]

[0085] 100: Semiconductor device 1: Semiconductor module 2:Laminated substrate 3: Semiconductor elements 4: Semiconductor elements 5: Mold resin 6: Circuit board 10: Heat sink 11: Mounting surface 12: Lower mold 13: Upper mold 20: Insulating plate 21: Heat sink 21a: Heat sink 22: Circuit board 23: Terminal material 24: Terminal material 25: Terminal material 26: Runner Club 27: Heat sink 28: Heat sink 29: Heat dissipation material 30: Gate electrode B: Bending line L: Boundary line S: Bonding material W: Wiring material

Claims

1. a laminated substrate formed by laminating an insulating plate having an upper surface and a lower surface, a heat sink disposed on the lower surface of the insulating plate, and a plurality of circuit boards disposed on the upper surface of the insulating plate; a semiconductor device disposed on an upper surface of each of the circuit boards; The plurality of circuit boards are arranged side by side in a predetermined direction in a plan view, the lower surface of the heat sink has a plurality of heat dissipation regions separated along the boundary lines of the adjacent circuit boards and arranged side by side in the predetermined direction in a plan view; the insulating plate is curved along the predetermined direction so as to be convex on one side in a thickness direction, The heat sink is divided into a plurality of pieces along the boundary line, A semiconductor module, wherein the area of ​​the heat sink in a plan view is larger than the area of ​​the corresponding circuit board.

2. the plurality of heat dissipation regions are disposed at locations corresponding to the positions directly below the plurality of circuit boards; The semiconductor module according to claim 1 , wherein the insulating plate is curved from a boundary line of the adjacent circuit board or the heat dissipation area.

3. The semiconductor module according to claim 2 , wherein the boundary line extends in a direction intersecting the predetermined direction.

4. 4. The semiconductor module according to claim 1, wherein a three-phase inverter circuit is formed by a plurality of the circuit boards and semiconductor elements arranged on upper surfaces of the circuit boards, and the circuit boards forming each phase of the three-phase inverter circuit are arranged side by side in the predetermined direction.

5. 5. The semiconductor module according to claim 4, wherein in each phase of the three-phase inverter circuit, the circuit board constituting the upper arm and the circuit board constituting the lower arm are arranged side by side in the predetermined direction.

6. a first terminal member connected to the circuit board and constituting a wiring for a main current; the first terminal member is formed of an elongated body extending in a direction intersecting the predetermined direction, 6. The semiconductor module according to claim 5, wherein the first terminal members provided on each of the circuit boards are arranged side by side in the predetermined direction.

7. a second terminal member disposed on a side of the circuit board constituting the lower arm; 7. The semiconductor module according to claim 6, wherein the second terminal members are formed as elongated bodies extending in a direction intersecting the predetermined direction, and are disposed adjacent to and extending parallel to the first terminal members.

8. a third terminal member disposed on the opposite side of the circuit board from the first terminal member; The semiconductor module according to claim 7 , wherein the third terminal member is formed as an elongated body extending in a direction intersecting the predetermined direction.

9. the first terminal member on the upper arm side constitutes a high-potential input terminal, the first terminal member on the lower arm side constitutes an output terminal for each phase, the second terminal member constitutes a low-potential side input terminal, the third terminal member constitutes a gate terminal, The semiconductor module according to claim 8 , wherein the third terminal member is electrically connected to a gate electrode of the semiconductor element.

10. 10. The semiconductor module according to claim 1, wherein the heat sink in plan view includes the entire area directly below the corresponding circuit board.

11. A semiconductor module described in any one of claims 1 to 10, wherein the insulating plate is a single continuous piece, and the upper and lower surfaces along the boundary line are exposed.

12. A semiconductor module described in any one of claims 1 to 11, wherein the gap between adjacent heat sink plates has an area smaller than the gap between adjacent circuit boards in a planar view.

13. A semiconductor module described in any one of claims 1 to 12, wherein another heat sink having less rigidity than the heat sink is arranged between two adjacent heat sinks on the underside of the insulating plate.

14. A semiconductor module described in any one of claims 1 to 12, wherein the heat sinks of the same shape are shifted in the specified direction and arranged so that part of them overlap in the thickness direction, and the whole is formed into an expandable shutter shape.

15. a laminated substrate preparation process for preparing a laminated substrate by laminating an insulating plate having an upper surface and a lower surface, a plurality of circuit boards arranged side by side in a predetermined direction in a plan view on the upper surface of the insulating plate, and a heat dissipation plate arranged on the lower surface of the insulating plate, the lower surface being separated along the boundary line between adjacent circuit boards, the heat dissipation plate having a plurality of heat dissipation regions arranged side by side in the predetermined direction in a plan view, the heat dissipation plate being divided into a plurality of pieces along the boundary line, and the area in a plan view being larger than the area of ​​the corresponding circuit board; a chip placement step of placing a semiconductor element on the upper surface of each of the circuit boards; a bending step of bending the insulating plate along the predetermined direction so that it is convex on one side in a thickness direction.

16. The method for manufacturing a semiconductor module according to claim 15 , further comprising a molding step of sealing the laminated substrate and the semiconductor element with a molding resin after the bending step.

17. In the laminated substrate preparation step, the laminated substrate is formed of a metal wiring board in which the plurality of circuit boards and the plurality of terminal members are integrally connected via runner portions, 17. The method for manufacturing a semiconductor module according to claim 15, further comprising a terminal molding step of removing the runner portion to mold the plurality of terminal members.

18. The method for manufacturing a semiconductor module according to claim 17 , further comprising, after the terminal molding step, a circuit board placement step of placing a circuit board on the plurality of terminal members.

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