Semiconductor module, power conversion device, and method for manufacturing semiconductor module

Abstract

To solve the problem that when an electronic component is sealed together with a plurality of power semiconductor elements, a gap where a sealing member flows becomes narrow to form a void, etc., and then a semiconductor module may decrease in reliability.SOLUTION: A semiconductor module comprises a plurality of power semiconductor elements which are arrayed in parallel, a first conductor plate and a second conductor plate which are joined to top surfaces and reverse surfaces of the plurality of power semiconductor elements arrayed in parallel, a wiring board which is provided on the second conductor plate, and an electronic component which is mounted on the wiring board, wherein the plurality of power semiconductor elements, the first conductor plate, the second conductor plate, the wiring board, and the electronic component are sealed with a sealing member. The first conductor plate located on the top surface side of the wiring board has at least one of a recessed part and a through hole formed in a region on the wiring board which faces the electronic component.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a semiconductor module, a power conversion device, and a method for manufacturing a semiconductor module. [Background technology]

[0002] Power conversion devices using switching of power semiconductor elements have high conversion efficiency and are widely used in consumer, automotive, railway, substation equipment, etc. In recent years, because power semiconductor elements have a limit to the current they can pass, efforts have been made to increase output power to handle large currents by connecting multiple power semiconductor elements in parallel. On the other hand, electronic components such as gate resistors to add the charge required for driving to the gate of the power semiconductor element and chip capacitors to smooth surges during switching of the power semiconductor element are required around the power semiconductor element. In a semiconductor module that encapsulates multiple power semiconductor elements, it is necessary to encapsulate these electronic components as well.

[0003] Patent Document 1 discloses a power conversion device in which a plurality of power semiconductor elements are connected in parallel. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-068534 A Summary of the Invention [Problem to be solved by the invention]

[0005] When sealing electronic components together with a plurality of power semiconductor elements, the gap through which the sealing material flows can become narrow, resulting in the generation of voids and the like, which can reduce the reliability of the semiconductor module. [Means for solving the problem]

[0006] A semiconductor module according to the present invention comprises a plurality of power semiconductor elements arranged in parallel, a first conductor plate and a second conductor plate joined to upper and lower surfaces, respectively, of the plurality of power semiconductor elements arranged in parallel, a wiring board provided on the second conductor plate, and electronic components mounted on the wiring board, wherein the plurality of power semiconductor elements, the first conductor plate and the second conductor plate, the wiring board, and the electronic components are sealed with a sealing member, and at least one of a recess and a through hole is formed in the first conductor plate located on the upper surface side of the wiring board in an area facing the electronic components on the wiring board. A method for manufacturing a semiconductor module according to the present invention is a method for manufacturing a semiconductor module comprising: a plurality of power semiconductor elements arranged in parallel; a first conductor plate and a second conductor plate joined to upper and lower surfaces, respectively, of the plurality of power semiconductor elements arranged in parallel; a wiring board provided on the second conductor plate; and electronic components mounted on the wiring board, wherein the plurality of power semiconductor elements, the first conductor plate and the second conductor plate, the wiring board, and the electronic components are sealed with a sealing material, and includes a step of pouring the sealing material into recesses or through holes formed in the first conductor plate located on the upper surface side of the wiring board in an area facing the electronic components on the wiring board to seal the first conductor plate. Effect of the Invention

[0007] According to the present invention, it is possible to provide a highly reliable semiconductor module that suppresses the occurrence of voids and the like. [Brief description of the drawings]

[0008] [Figure 1] FIG. [Diagram 2] FIG. [Diagram 3] FIG. 2 is a plan view of a semiconductor module. [Figure 4] FIG. 2 is a plan view showing an internal structure of the semiconductor module. [Diagram 5] 3(a), (b), and (c) are cross-sectional views of a semiconductor module. [Figure 6] 5A to 5C are cross-sectional views showing a manufacturing process of the semiconductor module. [Figure 7] 1A and 1B are cross-sectional views showing the manufacturing process of a comparative example. [Figure 8] 1A and 1B are diagrams illustrating a semiconductor module according to a first modified example. [Figure 9] 5A to 5C are cross-sectional views showing a manufacturing process of the semiconductor module 300 according to the first modification. [Figure 10] 10(a), (b), and (c) are cross-sectional views showing a manufacturing process for a semiconductor module according to Modification 2. [Figure 11] 10(a), (b), and (c) are external perspective views showing a manufacturing process for the emitter-side conductive plate. [Figure 12] 1A and 1B are diagrams showing the shape of a through hole. [Figure 13] FIG. 2 is a circuit diagram of a semiconductor module. [Figure 14] 1 is a circuit diagram of a power conversion device using a semiconductor module. [Figure 15] 1 is an external perspective view showing an example of a power conversion device; [Figure 16] FIG. 2 is a cross-sectional view of a power conversion device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and appropriate omissions and simplifications have been made for clarity of explanation. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0010] In order to facilitate understanding of the invention, the position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0011] When there are multiple components having the same or similar functions, they may be described by using the same reference numerals with different subscripts. However, when there is no need to distinguish between these multiple components, the subscripts may be omitted.

[0012] FIG. 1 is a plan view of the electric circuit body 400. The electric circuit body 400 is composed of a semiconductor module 300 and a cooling member 340. Three semiconductor modules 300 are provided, and have a function of converting DC current and AC current using power semiconductor elements. Since the semiconductor modules 300 generate heat when energized, the heat is cooled by a coolant flowing in the cooling member 340. The coolant may be water or an antifreeze liquid in which ethylene glycol is mixed with water. Each semiconductor module 300 is provided with power terminals through which a large current flows, such as a positive terminal 315B and a negative terminal 319B connected to a capacitor module 500 (see FIG. 14) of a DC circuit, and an AC terminal 320B connected to motor generators 192 and 194 (see FIG. 14) of an AC circuit. The semiconductor modules 300 are also provided with signal terminals used for controlling the semiconductor modules 300, such as a lower arm gate terminal 325L, an emitter sense signal terminal 325E, a collector sense signal terminal 325C, and an upper arm gate terminal 325U.

[0013] Fig. 2 is a cross-sectional view of the electric circuit body 400. This cross-sectional view is a cross-sectional view taken along the line AA shown in Fig. 1. Fig. 3 is a plan view of the semiconductor module 300. One semiconductor module 300 mounted on the electric circuit body 400 shown in Fig. 1 is shown.

[0014] The power semiconductor element 155 (see FIG. 4) forming the upper arm circuit is configured by arranging five elements in each row in two rows and connecting them in parallel. The power semiconductor element 155 may be made of Si, SiC, GaN, GaO, C, etc. When a body diode of the power semiconductor element is used, a separate diode may be omitted. The collector side of the power semiconductor element 155 is joined to a second conductor plate 431. The joining member used for this joining may be solder or sintered metal. The first conductor plate 430 is joined to the emitter side of the power semiconductor element 155.

[0015] The power semiconductor element 157 (see FIG. 4) forming the lower arm circuit is configured by arranging five elements in two rows and connecting them in parallel. The collector side of the power semiconductor element 157 is joined to the fourth conductor plate 433 (see FIG. 5(b)). The emitter side of the power semiconductor element 157 is joined to the third conductor plate 432 (see FIG. 5(b)).

[0016] The conductive plates 430, 431, 432, and 433 are not particularly limited as long as they are made of a material having high electrical conductivity and thermal conductivity, but copper-based or aluminum-based materials are preferable. These may be used alone, or may be plated with Ni, Ag, or the like to improve bonding with solder or sintered metal. The conductive plates 430, 431, 432, and 433 serve as heat transfer members that transfer heat generated by the power semiconductor elements 155 and 157 to the cooling member 340 in addition to passing electric current. The conductive plates 430, 431, 432, and 433 and the cooling member 340 have different electric potentials, so insulating layers 442 and 443 (see FIG. 2) are provided between them. The insulating layers 442 and 443 may be resin-based or ceramic-based. The ceramic-based insulating layer has the advantage of excellent thermal conductivity. Furthermore, the resin-based insulating layer has the advantage of being adhesive and excellent in productivity because it can be pressure-bonded to the conductive plates 430, 431, 432, and 433. In this embodiment, an example of a resin-based insulating layer is shown.

[0017] The insulating layers 442 and 443 are combined with a metal foil 444 to form sheet members 440 and 441, and the insulating layers 442 and 443 are pressed against the conductive plates 430, 431, 432, and 433 to form an insulating sheet having adhesiveness only on one side, which can improve workability during production. In addition, the insulating layers 442 and 443 can be protected by forming the metal foil 444 on the side that contacts the cooling member 340. A heat conductive member 453 is provided between the sheet members 440 and 441 and the cooling member 340 to reduce contact thermal resistance. The power semiconductor elements 155 and 157 and the conductive plates 430, 431, 432, and 433 are sealed with a sealing member 360 such as a sealing resin by transfer molding. The ends of the sheet members 440 and 441 may be embedded in the sealing member 360 to prevent the sheet members 440 and 441 from peeling off from the ends.

[0018] Fig. 4 is a plan view showing the internal structure of semiconductor module 300. Fig. 4 shows a state in which first sheet member (emitter side) 440, first conductor plate (emitter side of upper arm circuit) 430, and third conductor plate (emitter side of lower arm circuit) 432 have been removed from the plan view of semiconductor module 300 in Fig. 3.

[0019] As shown in FIG. 4, the power semiconductor elements 155 forming the upper arm circuit are arranged in two rows, five in each row, on the second conductor plate 431. Similarly, the power semiconductor elements 157 forming the lower arm circuit are arranged in two rows, five in each row, on the fourth conductor plate 433. Between the power semiconductor elements 155, 157 arranged in parallel, a wiring board 372a is provided on the conductor plates 431, 433. Signal wiring is provided on the wiring board 372a to connect the power semiconductor elements 155, 157 to signal terminals such as the lower arm gate terminal 325L, the emitter sense signal terminal 325E, the collector sense signal terminal 325C, and the upper arm gate terminal 325U. Chip resistors 370 are provided on the signal wiring connected to the gates of the power semiconductor elements 155, 157. By placing wiring board 372a between the respective arrangements of power semiconductor elements 155, 157, wiring for power semiconductor elements 155, 157 on both sides can be routed using a single wiring board 372a, thereby reducing the number and area of ​​wiring boards 372a and improving efficiency.

[0020] A wiring board 372b is provided on the ends of the conductor plates 431 and 433 via an adhesive 373. Signal wiring connecting the power semiconductor elements 155 and 157 to the signal terminals is provided on the wiring board 372b, and a chip capacitor 371 is disposed on the signal wiring. When next-generation devices such as SiC are used as the power semiconductor elements 155 and 157 and switching is performed at high speed, a part of the smoothing capacitor is installed as the chip capacitor 371 in the semiconductor module 300. In this case, the chip capacitor 371 provided in the semiconductor module 300 can reduce the inductance. This makes it possible to smooth surges during high-speed switching that cannot be smoothed by a smoothing capacitor provided outside the semiconductor module 300, which has a high inductance.

[0021] Although an example will be described in which chip resistors 370 and chip capacitors 371 are arranged on wiring boards 372a and 372b, other electronic components including chip resistors 370 and chip capacitors 371 may be arranged. For example, electronic components such as a fault diagnosis IC, a current sensor, and a temperature sensor may be mounted on wiring boards 372a and 372b to enhance functionality. Furthermore, wiring boards 372a and 372b may be multilayer boards having a multilayer structure with insulating layers sandwiched between them.

[0022] Figures 5(a), 5(b), and 5(c) are cross-sectional views of the semiconductor module 300. Figure 5(a) is a cross-sectional view of the line BB shown in Figure 4, Figure 5(b) is a cross-sectional view of the line CC shown in Figure 4, and Figure 5(c) is a cross-sectional view of the line DD shown in Figure 4. Note that the cross-sectional views show a state in which a first sheet member (emitter side) 440 and a first conductor plate (upper arm circuit emitter side) 430, which were removed in Figure 4, are provided.

[0023] 5(a), chip capacitor 371 is disposed on wiring board 372b. Conductive plate 430 located on the upper surface side of wiring board 372b has recess 434 formed in an area facing chip capacitor 371 on wiring board 372b.

[0024] 5(b), chip resistor 370 is disposed on wiring substrate 372a. Conductive plates 430, 432 located on the upper surface side of wiring substrate 372a have recesses 434 formed in areas facing chip resistor 370 on wiring substrate 372a.

[0025] As shown in FIG. 5(c), the conductive plates 430 and 432 located on the upper surface side of the wiring board 372a have recesses 434 formed in areas facing the chip resistors 370 on the wiring board 372a. The recesses 434 are provided along the direction of arrangement of the multiple power semiconductor elements 155 and 157. Gaps are formed on both sides of the wiring board 372a. The gaps and the recesses 434 are filled with the sealing material in the transfer molding process. In this case, the recesses 434 are provided to prevent the sealing material from being blocked by the electronic components installed on the wiring boards 372a and 372b. As a result, when sealing the electronic components together with the multiple power semiconductor elements, the gap through which the sealing material flows becomes narrower, and voids or the like are generated, which reduces the reliability of the semiconductor module 300. Furthermore, the thickness of the semiconductor module 300 is not increased, and a highly reliable semiconductor module 300 can be provided.

[0026] 6A to 6C are cross-sectional views showing a manufacturing process of the semiconductor module 300. As in FIG. 5C, these are cross-sectional views taken along the line DD shown in FIG. A semiconductor module 300 (hereinafter referred to as a circuit body 310) before being sealed with a sealing member 360 is placed in a mold in a transfer molding apparatus 601. This circuit body 310 includes power semiconductor elements 155, 157, conductive plates 431, 433 joined to the upper and lower surfaces of the power semiconductor elements 155, 157, wiring boards 372a, 372b provided on the conductive plates 431, 433, and electronic components such as a chip resistor 370 and a chip capacitor 371 mounted on the wiring boards 372a, 372b.

[0027] The transfer molding device 601 includes a mechanism for vacuum-adsorbing the spring 602 and the sheet members 440 and 441 to the mold, and a vacuum degassing mechanism. The transfer molding device 601 holds the sheet members 440 and 441 by vacuum adsorption in a mold that has been heated to a constant temperature of 175°C in advance. Next, the upper and lower molds are brought close to each other from a state in which the sheet members 440 and 441 and the circuit body 310 are separated, and only the packings installed around the upper and lower molds (not shown) are brought into contact with each other. Then, the mold cavity is evacuated. When the evacuation is completed to a predetermined air pressure or less, the packings are further crushed and the upper and lower molds are completely clamped. At this time, the sheet members 440 and 441 come into contact with the circuit body 310. In a vacuum state, the sheet members 440 and 441 come into contact with the circuit body 310, and are tightly attached by the pressure of the spring 602, so that they can be tightly attached without involving voids. Then, in a transfer molding process, the sealing member 360 is injected into the mold cavity through the injection port 365 .

[0028] As already explained, the conductive plates 430 and 432 are formed with recesses 434. For example, the gap between the electronic components and the conductive plates 430 and 432 is secured to be 240 μm or more, so that the sealing member 360 is reliably filled on the electronic components in the transfer molding process. The filler filled in the sealing member 360 is 80 μm or less, but if it is less than three times the maximum particle size, the filler may be unevenly distributed during flow and the resin strength may decrease. By making the gap between the electronic components and the conductive plates 430 and 432 240 μm or more, the resin strength of the part sealed in the recesses 434 is secured, and there is an effect of increasing reliability against thermal stress such as temperature change. In addition, the sheet members 440 and 441 including the insulating layers 442 and 443 are pressure-bonded in the transfer molding process, thereby improving productivity.

[0029] In the next curing step, the semiconductor module 300 sealed with the sealing member 360 is taken out from the transfer molding device 601 and cooled to room temperature, after which curing is carried out for 2 hours or more.

[0030] 7(a) and 7(b) are cross-sectional views showing the manufacturing process of a comparative example. This comparative example is shown to compare an example in which the present embodiment is not used with the present embodiment. The same parts as those in FIG. 6 are given the same reference numerals and will be described briefly.

[0031] Fig. 7(a) shows an example in which recesses 434 are not formed in conductor plates 430, 432. If recesses 434 are not provided in conductor plates 430, 432 as shown in Fig. 7(a), it is difficult to mount electronic components on wiring board 362. Even if wiring board 362 is installed, the gap between wiring board 362 and conductor plates 430, 432 will be less than 240 µm, which may result in unfilled portions of sealing member 360 or insufficient resin strength in filled portions.

[0032] 7(b) shows an example in which a spacer 438 is inserted between the emitter-side conductive plates 430 and 432 and the collector-side conductive plates 431 and 433 to ensure a gap. Note that the transfer molding device 601 is not shown. In this case, although the fluidity of the sealing member 360 improves, the spacer 438 becomes taller, which deteriorates the thermal conduction to the emitter-side conductive plates 430 and 432, thereby reducing the heat dissipation performance.

[0033] In this embodiment, compared to such comparative examples, by forming recesses 434 in emitter-side conductor plates 430, 432 to increase the fluidity of sealing member 360, it is possible to mount electronic components on wiring board 362, maintain the resin strength of the filling portion of sealing member 360, and maintain heat dissipation properties.

[0034] 8(a) and 8(b) are diagrams showing a semiconductor module 300 according to the first modification. FIG. 8(a) is a semi-transparent diagram showing the internal structure of the semiconductor module 300. FIG. 8(a) shows a state in which the first sheet member (emitter side) 440 is removed from the plan view of the semiconductor module 300 in FIG. 3, that is, a state in which the first conductor plate (emitter side of the upper arm circuit) 430 and the third conductor plate (emitter side of the lower arm circuit) 432 are joined to the power semiconductor elements 155 and 157 in FIG. 4. FIG. 8(b) is an enlarged view of an area T in FIG. 8(a), and FIG. 8(c) is a cross-sectional view of the line EE in FIG. 8(a). The same reference numerals are assigned to the same parts as in FIG. 4, and the description will be simplified.

[0035] As shown in FIG. 8(a), the conductive plates 430, 432 located on the upper surface side of the wiring boards 372a, 372b have through holes 435 formed in areas facing the electronic components (chip resistors 370 and chip capacitors 371) on the wiring boards 372a, 372b.

[0036] Through holes 435 are provided, so that the flowing sealing material is prevented from being blocked by the electronic components mounted on wiring boards 372a, 372b in the transfer molding process. As a result, when sealing electronic components together with a plurality of power semiconductor elements, the gap through which the sealing material flows is narrowed, and voids are not generated, which reduces the reliability of semiconductor module 300. Also, a highly reliable semiconductor module 300 can be provided without increasing the thickness of semiconductor module 300.

[0037] The through holes 435 provided in the region facing the chip resistor 370 are provided at positions that do not overlap with the straight path P connecting the power semiconductor elements 155, 157 facing each other with the wiring board 372a in between, and are provided in multiple numbers along the arrangement direction of the power semiconductor elements 155, 157. By forming the through holes 435 at positions that do not overlap with the straight path P connecting the power semiconductor elements 155, 157 and the power semiconductor elements 155, 157 at the shortest distance, it is possible to prevent leakage current from bypassing the through holes 435 and increasing inductance. Specifically, the straight path P is an area defined by the opposing width W of the power semiconductor elements 155, 157 and the distance between them. The through holes 435 are provided so as not to enter this area. 8(b), the straight line path Q is a region defined by the range of +W×1 / 4, -W×1 / 4 from the center line of the width W of the power semiconductor elements 155, 157 facing each other with the wiring boards 372a, 372b in between (the range of W×2 / 4 at the center of the width W) and the distance between them. At least, the through hole 435 is provided so as not to enter this straight line path Q.

[0038] 9A to 9C are cross-sectional views showing a manufacturing process of the semiconductor module 300 according to the modified example 1. The same parts as those in Fig. 6 are given the same reference numerals and will be briefly described. As shown in Fig. 8A, a through hole 435 is formed in the conductive plates 430 and 432. First, the semiconductor module 300 (the circuit body 310 provided with the sheet members 440, 441) before being sealed with the sealing member 360 is placed in a mold in the transfer molding device 601. This semiconductor module 300 includes the power semiconductor elements 155, 157, the conductor plates 431, 433 joined to the upper and lower surfaces of the power semiconductor elements 155, 157, the sheet members 440, 441 sandwiching the outer surfaces of the conductor plates 431, 433 and the conductor plates 430, 432 from both sides, the wiring boards 372a, 372b provided on the conductor plates 431, 433, the wiring boards 372a, 372b provided on the conductor plates 431, 433, and electronic components such as a chip resistor 370 and a chip capacitor 371 mounted on the wiring boards 372a, 372b.

[0039] The transfer molding device 601 includes a mechanism for vacuum-adsorbing the spring 602 and the sheet members 440 and 441 to the mold, and a vacuum degassing mechanism. The transfer molding device 601 holds the sheet members 440 and 441 by vacuum adsorption in a mold that has been heated to a constant temperature of 175°C in advance. Next, the upper and lower molds are brought close to each other from a state in which the sheet members 440 and 441 and the circuit body 310 are separated, and only the packings installed around the upper and lower molds (not shown) are brought into contact with each other. Then, the mold cavity is evacuated. When the evacuation is completed to a predetermined air pressure or less, the packings are further crushed and the upper and lower molds are completely clamped. At this time, the sheet members 440 and 441 come into contact with the circuit body 310. In a vacuum state, the sheet members 440 and 441 come into contact with the circuit body 310, and are tightly attached by the pressure of the spring 602, so that they can be tightly attached without involving voids.

[0040] Then, in the transfer molding process, sealing member 360 is injected into the mold cavity through injection port 361. Since through holes 435 are formed in emitter-side conductor plates 430, 432, the fluidity of sealing member 360 is not impaired even when a tall electronic component is mounted on wiring board 362, and the heat dissipation performance of the semiconductor module can be maintained.

[0041] 10(a), 10(b), and 10(c) are cross-sectional views showing a manufacturing process of a semiconductor module 300 according to Modification 2. The same parts as those in FIG. 9 are given the same reference numerals and will be briefly described.

[0042] A semiconductor module 300' before sealing with a sealing member 360 is placed in a metal mold in a transfer molding device 601. This semiconductor module 300' is in a state before the sheet members 440, 441 are provided. That is, the semiconductor module 300' includes power semiconductor elements 155, 157, conductive plates 431, 433 bonded to the upper and lower surfaces of the power semiconductor elements 155, 157, wiring boards 372a, 372b provided on the conductive plates 431, 433, wiring boards 372a, 372b provided on the conductive plates 431, 433, and electronic components such as a chip resistor 370 and a chip capacitor 371 mounted on the wiring boards 372a, 372b. An overmolded portion 363, which is a gap, is formed between the metal mold in the transfer molding device 601 and the conductive plates 431, 433.

[0043] Then, in the transfer molding process, sealing member 360 is injected into the mold cavity through injection port 361. Since sealing member 360 flows through overmolded portion 363 and through-hole 435, even if a tall electronic component is mounted on wiring board 362, the fluidity of sealing member 360 is not impaired, and the filling property of sealing member 360 is dramatically improved. Therefore, the heat dissipation property of the semiconductor module can be maintained.

[0044] FIG. 10B shows a grinding step. After the sealing member 360 has hardened, the semiconductor module 300' is taken out and ground down to a ground surface 364 where the emitter-side conductive plates 430, 432 are exposed. FIG. 10(c) shows a pressure bonding step, in which sheet members 440 and 441 are pressure bonded to both sides of the semiconductor module 300' after the grinding step.

[0045] 11(a), 11(b), and 11(c) are external perspective views showing the manufacturing process of the emitter-side conductive plates 430 and 432. FIG. 11(a) shows the manufacturing process of a copper plate. A recess 434 is formed in the copper plate used as the conductor plates 430 and 432. A protrusion 437 is formed on both sides of the recess 434 in the direction along the groove. This improves productivity by manufacturing the recess 434 and the protrusion 437 as a drawn material.

[0046] 11(b) shows a protrusion forming process. The protrusions 436 are provided by pressing the convex portions 437 to make depressions at predetermined intervals. The recesses 434 are provided along the direction of arrangement of the power semiconductor elements 155, 157. The wiring board 372a is then placed in correspondence with the recesses 434. Therefore, the protrusions 436 are provided on both sides of the wiring board 372a at predetermined intervals in the direction of arrangement of the power semiconductor elements 155, 157. As a result, in the transfer molding process, the sealing material also flows between the protrusions 436, suppressing the occurrence of voids and the like, thereby improving the reliability of the semiconductor module 300.

[0047] 11(c) shows a through hole forming step. When forming the through holes 435, holes are opened at predetermined intervals in the recess 434. The through holes 435 are provided at positions that do not overlap with the straight line paths P, Q connecting the power semiconductor elements 155, 157 facing each other across the wiring board 372a, and are provided in a plurality of positions along the arrangement direction of the power semiconductor elements 155, 157.

[0048] Figures 12(a) and 12(b) are diagrams showing the shape of through-hole 435. Figure 12(a) is a cross-sectional view, and Figure 12(b) is a plan view in a state where sheet member 440 has been removed. 12(a), by providing chamfering or R processing 435r to through-hole 435 of conductive plate 430 on the emitter side, stress at the contact portion between conductive plate 430 and sheet member 440 is alleviated, improving reliability of semiconductor module 300. Also, as shown in Fig. 12(b), by providing R or chamfer 435r when conductive plate 430 is viewed from above, stress at the contact portion between conductive plate 430 and sheet member 440 is alleviated, improving reliability.

[0049] FIG. 13 is a circuit diagram of the semiconductor module 300. The terminal 315B is output from the collector side of the upper arm circuit and is connected to the positive side of a battery or a capacitor. The terminal 325U is output from the gate and emitter sense of the power semiconductor element 155 of the upper arm circuit. The terminal 319B is output from the emitter side of the lower arm circuit and is connected to the negative side of a battery or a capacitor, or GND. The terminal 325L is output from the gate and emitter sense of the power semiconductor element 157 of the lower arm circuit. The terminal 320B is output from the collector side of the lower arm circuit and is connected to a motor. When the neutral point is grounded, the lower arm circuit is connected to the negative side of a capacitor, not GND. Chip resistors 370 are provided between the gate terminal 325U and the power semiconductor element 155 and between the gate terminal 325L and the power semiconductor element 157, respectively, to stabilize the charge applied to the gate. Terminal 325C is a terminal for a collector sense signal, and terminal 325E is a terminal for an emitter sense signal.

[0050] Furthermore, chip capacitors 371 are provided between the second conductor plate 431 and the positive electrode terminal 315B and between the third conductor plate 432 and the negative electrode terminal 319B to smooth out surges that occur during high-speed switching.

[0051] 13, power semiconductor elements 155 and 157 are each represented by a single symbol, but as described with reference to FIG. 3, power semiconductor elements 155 are arranged in two rows, five elements in each row. Similarly, power semiconductor elements 157 are arranged in two rows, five elements in each row. That is, power semiconductor elements 155 and 157 use ten power semiconductor elements in parallel to increase the current that can be passed and increase output. Note that the number of power semiconductor elements used in parallel is just an example, and multiple power semiconductor elements are used in parallel depending on the required output.

[0052] When the power semiconductor elements 155, 157 are used in multiple parallel connections, it is desirable to provide a gate resistor for each of the multiple parallel elements in order to prevent malfunction of the power semiconductor elements 155, 157. A wiring board 372a having a chip resistor 370 mounted thereon as this gate resistor is built into the semiconductor module 300.

[0053] The semiconductor module 300 of the present embodiment has a 2-in-1 structure in which two arm circuits, an upper arm circuit and a lower arm circuit, are integrated into one semiconductor module 300. Note that, in addition to the 2-in-1 structure, other structures may include a 3-in-1 structure in which two arm circuits, an upper arm circuit and a lower arm circuit, and one arm circuit, an upper arm circuit or a lower arm circuit, are integrated into one semiconductor module 300, a 4-in-1 structure in which four arm circuits, an upper arm circuit and a lower arm circuit, are integrated into one semiconductor module 300, and a 6-in-1 structure in which six arm circuits, an upper arm circuit and a lower arm circuit, are integrated into one semiconductor module 300.

[0054] FIG. 14 is a circuit diagram of a power conversion device 200 using a semiconductor module 300. The power conversion device 200 includes inverter circuit units 140 and 142, an inverter circuit unit 43 for auxiliary equipment, and a capacitor module 500. The inverter circuit units 140 and 142 include a plurality of semiconductor modules 300, which are connected to form a three-phase bridge circuit. When the current capacity is large, the semiconductor modules 300 are further connected in parallel, and these parallel connections are made corresponding to each phase of the three-phase inverter circuit, thereby making it possible to increase the current capacity. As described in this embodiment, the active elements 155 and 157 and the diodes 156 and 158, which are power semiconductor elements built into the semiconductor module 300, can also be connected in parallel to make it possible to increase the current capacity.

[0055] The inverter circuit unit 140 and the inverter circuit unit 142 have the same basic circuit configuration, and the control method and operation are also basically the same. Since the outline of the circuit operation of the inverter circuit unit 140 and the like is well known, a detailed description will be omitted here.

[0056] As described above, the upper arm circuit includes upper arm active element 155 and upper arm diode 156 as switching power semiconductor elements, and the lower arm circuit includes lower arm active element 157 and lower arm diode 158 as switching power semiconductor elements. Active elements 155 and 157 perform switching operation upon receiving a drive signal output from one or the other of two driver circuits constituting driver circuit 174, and convert DC power supplied from battery 136 into three-phase AC power.

[0057] It should be noted that a MOSFET (metal oxide semiconductor field effect transistor) may be used as the active element, in which case the upper arm diode 156 and the lower arm diode 158 are not necessary.

[0058] The positive terminal 315B and the negative terminal 319B of each upper and lower arm series circuit are each connected to a DC terminal for connecting a capacitor of the capacitor module 500. AC power is generated at the connection portion between the upper arm circuit and the lower arm circuit, and the connection portion between the upper arm circuit and the lower arm circuit of each upper and lower arm series circuit is connected to the AC side terminal 320B of each semiconductor module 300. The AC side terminal 320B of each semiconductor module 300 of each phase is each connected to the AC output terminal of the power conversion device 200, and the generated AC power is supplied to the stator winding of the motor generator 192 or 194.

[0059] The control circuit 172 generates a timing signal for controlling the switching timing of the upper arm active element 155 and the lower arm active element 157 based on input information from a control device and a sensor (e.g., a current sensor 180) on the vehicle side. The driver circuit 174 generates a drive signal for performing a switching operation on the upper arm active element 155 and the lower arm active element 157 based on the timing signal output from the control circuit 172. Note that 181, 182, and 188 are connectors.

[0060] The upper and lower arm series circuits include a temperature sensor (not shown), and temperature information about the upper and lower arm series circuits is input to the microcomputer. In addition, voltage information about the DC positive pole side of the upper and lower arm series circuits is input to the microcomputer. The microcomputer performs over-temperature detection and over-voltage detection based on this information, and if over-temperature or over-voltage is detected, it stops the switching operation of all upper arm active elements 155 and lower arm active elements 157, thereby protecting the upper and lower arm series circuits from over-temperature or over-voltage.

[0061] FIG. 15 is an external perspective view showing an example of the power converter 200 shown in FIG. 14, and FIG. 16 is a cross-sectional view of the power converter 200 shown in FIG. 15 taken along line XV-XV.

[0062] The power converter 200 includes a housing formed of a lower case 11 and an upper case 10 and having a substantially rectangular parallelepiped shape. An electric circuit body 400, a capacitor module 500, and the like are housed inside the housing. The electric circuit body 400 has a cooling flow path, and a cooling water inlet pipe 13 and a cooling water outlet pipe 14 communicating with the cooling flow path protrude from one side of the housing 12. As shown in FIG. 15, the lower case 11 has an opening on the upper side (Z direction), and the upper case 10 is attached to the lower case 11 by closing the opening of the lower case 11. The upper case 10 and the lower case 11 are formed of an aluminum alloy or the like, and are fixed in a sealed manner from the outside. The upper case 10 and the lower case 11 may be integrally configured. The housing 12 is formed into a simple rectangular parallelepiped shape, which makes it easy to attach to a vehicle or the like and also easy to produce.

[0063] A connector 17 is attached to one side surface in the longitudinal direction of the housing 12, and an AC terminal 18 is connected to this connector 17. In addition, a connector 21 is provided on the surface from which the cooling water inlet pipe 13 and the cooling water outlet pipe 14 are led out.

[0064] As shown in FIG. 16, an electric circuit body 400 is accommodated in the housing 12. A control circuit 172 and a driver circuit 174 are arranged above the electric circuit body 400, and a capacitor module 500 is accommodated on the DC terminal side of the electric circuit body 400. By arranging the capacitor module 500 at the same height as the electric circuit body 400, the power conversion device 200 can be made thinner, improving the degree of freedom of installation in a vehicle. An AC side terminal 320B of the electric circuit body 400 is connected to a bus bar 361 through a current sensor 180. In addition, a positive side terminal 315B and a negative side terminal 319B, which are DC terminals of the semiconductor module 300, are respectively connected to positive and negative terminals 362A and 362B of the capacitor module 500.

[0065] According to the embodiment described above, the following advantageous effects can be obtained. (1) The semiconductor modules 300 and 300' each include a plurality of power semiconductor elements 155 and 157 arranged in parallel, conductor plates 430 and 432 and conductor plates 431 and 433 respectively joined to the upper and lower surfaces of the plurality of power semiconductor elements 155 and 157 arranged in parallel, wiring boards 372a and 372b provided on the conductor plates 431 and 433, and electronic components 370 and 371 mounted on the wiring boards 372a and 372b. A number of power semiconductor elements 155, 157, conductive plates 430, 432, conductive plates 431, 433, wiring boards 372a, 372b, and electronic components 370, 371 are sealed with a sealing member 360, and at least one of a recess 434 and a through hole 435 is formed in the conductive plates 430, 432 located on the upper surface side of the wiring boards 372a, 372b in an area facing the electronic components 370, 371 on the wiring boards 372a, 372b. This makes it possible to suppress the occurrence of voids and the like and provide a highly reliable semiconductor module.

[0066] (2) A power semiconductor device including a plurality of power semiconductor elements 155, 157 arranged in parallel, conductive plates 430, 432 and conductive plates 431, 433 respectively joined to the upper and lower surfaces of the plurality of power semiconductor elements 155, 157 arranged in parallel, wiring boards 372a, 372b provided on the conductive plates 431, 433, and electronic components 370, 371 mounted on the wiring boards 372a, 372b. The manufacturing method of the semiconductor module 300, 300' in which the conductive plates 431, 433, the wiring boards 372a, 372b, and the electronic components 370, 371 are sealed with the sealing member 360 includes a step of pouring the sealing member 360 into the recesses 434 or through holes 435 formed in the conductive plates 430, 432 located on the upper surface sides of the wiring boards 372a, 372b in the areas facing the electronic components 370, 371 on the wiring boards 372a, 372b. This makes it possible to suppress the occurrence of voids and provide a highly reliable semiconductor module.

[0067] The present invention is not limited to the above-described embodiment, and other embodiments that are conceivable within the scope of the technical concept of the present invention are also included within the scope of the present invention as long as they do not impair the characteristics of the present invention. In addition, the above-described embodiment may be combined with a number of modified examples. [Explanation of symbols]

[0068] 11 lower case, 13 cooling water inlet pipe, 14 cooling water outlet pipe, 17 connector, 18 AC terminal, 21 connector, 43, 140, 142 inverter circuit section, 155, 157 power semiconductor element, 172 control circuit, 174 driver circuit, 180 current sensor, 181, 182, 188 connector, 192, 194 motor generator, 200 Power conversion device, 300, 300'...semiconductor module, 315B...positive electrode side terminal, 319B...negative electrode side terminal, 320B...AC side terminal, 325...signal terminal, 325C...collector sense terminal, 325L...lower arm gate terminal, 325E...emitter sense terminal, 325U...upper arm gate terminal, 340...cooling member, 360...sealing member, 361...injection port, 362...wiring board, 36 3...overmolded portion, 364...ground surface, 370...chip resistor, 371...chip capacitor, 372a, 372b...wiring board, 373...adhesive, 400...electrical circuit body, 420...conductor plate, 430...first conductor plate (upper arm circuit emitter side), 431...second conductor plate (upper arm circuit collector side), 432...third conductor plate (lower arm circuit emitter side), 433...fourth conductor plate (lower arm circuit emitter side), a first insulating layer (emitter side), a second insulating layer (collector side), a first insulating layer (emitter side), a first insulating layer (collector side), a metal foil, a thermal conductive member, a first insulating layer (emitter side), a second insulating layer (collector side), ...

Claims

1. A semiconductor module comprising: a plurality of power semiconductor elements arranged in parallel; a first conductor plate and a second conductor plate joined to upper and lower surfaces of the plurality of power semiconductor elements arranged in parallel, respectively; a wiring board provided on the second conductor plate; and electronic components mounted on the wiring board, wherein the plurality of power semiconductor elements, the first conductor plate, the second conductor plate, the wiring board, and the electronic components are sealed with a sealing member, a first conductive plate located on an upper surface side of the wiring board, the first conductive plate having at least one of a recess and a through hole formed in an area facing the electronic component on the wiring board;

2. 2. The semiconductor module according to claim 1, The recess is provided along a direction in which the plurality of power semiconductor elements are arranged.

3. 2. The semiconductor module according to claim 1, The through hole is provided in a position that does not overlap with a straight line path connecting the power semiconductor elements facing each other across the wiring board, and is provided in a plurality of positions along the arrangement direction of the power semiconductor elements.

4. 4. The semiconductor module according to claim 3, The straight line path is a range including W×2 / 4 of the center of the width W of the power semiconductor elements facing each other with the wiring board in between.

5. 2. The semiconductor module according to claim 1, the wiring board is provided between each of the plurality of power semiconductor elements arranged in parallel, The electronic component is a chip resistor.

6. 2. The semiconductor module according to claim 1, the wiring board is provided on an end of the second conductor plate, The electronic component is a semiconductor module that is a chip capacitor.

7. 2. The semiconductor module according to claim 1, A semiconductor module comprising: a sheet member including an insulating layer that is pressure-bonded to a side of the first conductor plate opposite to a side facing the plurality of power semiconductor elements, and to a side of the second conductor plate opposite to a side facing the plurality of power semiconductor elements.

8. A power conversion device comprising the semiconductor module according to claim 1, for converting DC power into AC power.

9. A method for manufacturing a semiconductor module comprising: a plurality of power semiconductor elements arranged in parallel; a first conductor plate and a second conductor plate joined to upper and lower surfaces of the plurality of power semiconductor elements arranged in parallel, a wiring board provided on the second conductor plate; and electronic components mounted on the wiring board, the plurality of power semiconductor elements, the first conductor plate, the second conductor plate, the wiring board, and the electronic components being sealed with a sealing member, the method comprising: a sealing member for sealing the first conductor plate located on the upper surface side of the wiring board, the sealing member being poured into a recess or a through hole formed in an area facing the electronic component on the wiring board.

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