Electrical circuit bodies and power converters

Abstract

To solve a problem in a semiconductor device and a cooling member which must be fixed together and whose terminals must be connected together, resulting in reduction in productivity.SOLUTION: An electrical circuit body includes: a semiconductor device in which a semiconductor element is sealed with a sealing material and in which terminals are led out from the semiconductor element; a substrate having wiring to which the terminals are connected; a cooling member arranged opposite the semiconductor device and cooling the heat generated by the semiconductor element; a fixing member fixing the cooling member to the semiconductor device; and a pressure member applying pressure to the fixing member in a direction in which the cooling member is in close contact with the semiconductor device. The fixing member includes a support portion that supports the connection between the terminals and the wiring by the pressure transmitted from the pressure member.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an electric circuit body and a power conversion device.

Background Art

[0002] Power conversion devices based on the switching operation of semiconductor elements are widely used in consumer applications, automotive applications, railway applications, substation equipment, etc. because of their high conversion efficiency. Semiconductor elements generate heat during the switching operation. Therefore, in a semiconductor device incorporating a semiconductor element, a cooling member for cooling the heat generated from the semiconductor element is disposed in close contact with the semiconductor device. Further, the semiconductor device connects terminals led out from the semiconductor element to the wiring of the substrate.

[0003] Patent Document 1 discloses a technique for an electric circuit module in which a heat dissipation member is mounted on a power semiconductor, the fixing jig for housing the power semiconductor is fixed to the heat dissipation member by screws, and wiring is connected to the terminal block of the fixing jig by screws.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The technique described in Patent Document 1 has a problem in that fixing the semiconductor device and the cooling member and connecting the terminals are each necessary, resulting in a decrease in productivity.

Means for Solving the Problems

[0006] The electric circuit body according to the present invention is formed by sealing a semiconductor element with a sealing material, A pair of main surfaces, the terminals from the semiconductor element each being led out Having a pair of sides,A semiconductor device, a circuit board having wiring to which the terminals are connected, and a device facing the semiconductor device On one of the pair of main surfaces It is positioned to cool the heat generated by the semiconductor element. First Cooling component, A second cooling member is provided, which is positioned on the other side of the pair of main surfaces facing the semiconductor device and which cools the heat generated by the semiconductor element. The aforementioned First The cooling member is fixed to the semiconductor device. First Fixing member and A second fixing member is integrally configured with the second cooling member and fixes the second cooling member to the semiconductor device, The aforementioned The first and second The cooling member is in close contact with the semiconductor device. In the direction of the above The first and second Fixing member each The system comprises a pressurizing member and the aforementioned First The fixing member is subjected to the pressure transmitted from the pressurizing member. By pressing the terminal against the wiring of the substrate placed on the second fixing member, Supporting the connection between the terminal and the wiring At the same time, the substrate is brought into close contact with the second fixing member via the terminals. Includes the support structure. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an electrical circuit body with excellent productivity. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a plan view of an electrical circuit body in an embodiment that includes a fixing member. [Figure 2] Figure 2 is a plan view of the electrical circuit in an embodiment in which the fixing members have been removed. [Figure 3] Figure 3 is a cross-sectional view of the electrical circuit along line XX. [Figure 4] Figure 4 is a cross-sectional perspective view of the YY line of the electrical circuit. [Figure 5] Figure 5 is a cross-sectional perspective view of the electrical circuit along line XX. [Figure 6] Figure 6 is a cross-sectional view illustrating the replacement of semiconductor devices. [Figure 7] Figure 7 is a semi-transparent plan view of a semiconductor device. [Figure 8] Figure 8 is a circuit diagram of a semiconductor device. [Figure 9] Figures 9(a) to 9(d) are cross-sectional views illustrating the manufacturing process of semiconductor devices. [Figure 10] Figures 10(a) and 10(b) are cross-sectional views illustrating the manufacturing process of the electric circuit body. [Figure 11] Figures 11(a) and 11(b) are cross-sectional views illustrating the integration process of the fixing member in the embodiment. [Figure 12] Figures 12(a) and 12(b) are cross-sectional views illustrating the integration process of the fixing member in Modification 1. [Figure 13] Figures 13(a) and 13(b) are cross-sectional views illustrating the integration process of the fixing member in Modification 2. [Figure 14] Figures 14(a) to 14(e) are cross-sectional views showing Modifications 3 to 7 of the electric circuit body. [Figure 15] Figure 15 is a cross-sectional view showing Modification 8 of the electric circuit body. [Figure 16] Figure 16 is a plan view of the electric circuit body in the comparative example. [Figure 17] Figure 17 is a circuit diagram of a power conversion device using a semiconductor device. [Figure 18] Figure 18 is an external perspective view of the power conversion device shown in Figure 17. [Figure 19] Figure 19 is a cross-sectional perspective view taken along line XV-XV of the power conversion device shown in Figure 18.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments 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 for the sake of clarity of explanation, appropriate omissions and simplifications have been made. The present invention can be implemented in various other forms. Unless otherwise particularly limited, each component may be singular or plural.

[0010] In the drawings, the positions, sizes, shapes, ranges, etc. of the respective components shown may not represent the actual positions, sizes, shapes, ranges, etc. for the purpose of facilitating understanding of the invention. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, ranges, etc. disclosed in the drawings.

[0011] When there are multiple components with the same or similar function, they may be described using the same symbol but with different subscripts. However, if it is not necessary to distinguish between these multiple components, the subscripts may be omitted in the description.

[0012] Figures 1 and 2 are plan views of the electrical circuit body 400 in an embodiment. Figure 1 is a plan view of the electrical circuit body 400 including the fixing member 344, and Figure 2 is a plan view of the electrical circuit body 400 with the fixing member 344 removed.

[0013] The electrical circuit body 400 consists of a semiconductor device 300, a cooling member 340, a fixing member 344, a substrate 350, a pressurizing member 341, etc. In the example shown in Figures 1 and 2, the electrical circuit body 400 is made up of three semiconductor devices 300 arranged in parallel.

[0014] The semiconductor device 300 contains semiconductor elements 155 and 157, which will be described later, enclosed in a sealing material 360. Both sides of the semiconductor device 300 dissipate heat generated by the switching operation of the semiconductor elements 155 and 157. Furthermore, the terminals connected to the semiconductor elements 155 and 157 are led out from the sealing material 360 on the sides of the semiconductor device 300. These terminals are power terminals through which large currents flow, such as the positive terminal 325P and negative terminal 325M connected to the capacitor module 500 (see Figure 17) of the DC circuit, and the AC terminal 325A connected to the motor generators 192 and 194 (see Figure 17) of the AC circuit.

[0015] Furthermore, terminals extending from the sealing material 360 on the side of the semiconductor device 300 include the lower arm gate terminal 325L, the collector sense terminal 325C, the emitter sense terminal 325E, and the upper arm gate terminal 325U. These terminals extending from the semiconductor device 300 are connected to wiring patterns on the substrate 350. An electrical circuit 400, which has three semiconductor devices 300 arranged in parallel, functions as a power converter 200 that converts DC current and AC current through the switching operation of semiconductor elements 155 and 157. Note that the number of semiconductor devices 300 in the electrical circuit 400 is not limited to three, but can be arbitrarily set according to various configurations of the electrical circuit 400.

[0016] The cooling member 340 is positioned opposite the semiconductor device 300 and cools the heat generated by the switching operation of the semiconductor elements 155 and 157. Specifically, the cooling member 340 has a flow channel through which a coolant flows, and the coolant flowing through the channel cools the heat generated from the semiconductor elements 155 and 157. The coolant used is water or an antifreeze solution made by mixing water with ethylene glycol. The cooling member 340 is preferably made of an aluminum-based material with high thermal conductivity and light weight. It is manufactured by extrusion molding, forging, brazing, etc.

[0017] The fixing member 344 is integrally formed with the cooling member 340 by bonding, welding, fitting, etc. The fixing member 344 then fixes the cooling member 340 to the semiconductor device 300 by the pressurizing member 341. The pressurizing member 341 can be any member that can continuously apply pressure to the fixing member 344 in a direction that causes the cooling member 340 to be in close contact with the semiconductor device 300. For example, it may be a screw as in this embodiment, or a U-shaped leaf spring that sandwiches the fixing member 344 from both sides of the semiconductor device 300 can be used.

[0018] The fixing member 344 also connects the terminals of the semiconductor device 300 to the wiring of the substrate 350 through the pressure transmitted from the pressurizing member 341. The configurations of the fixing member 344, the substrate 350, and the pressurizing member 341 will be described later.

[0019] The fixing member 344 can be made of a wide range of insulating materials. Resin materials such as thermosetting resins, thermoplastic resins, and silicone resins, as well as inorganic materials such as ceramics, can be used. Using resin materials facilitates the formation of complex structures. Using thermoplastic resins allows for integral molding with the cooling member 340 by injection molding, increasing productivity. When using resin materials for the fixing member 344, the mechanical properties can be improved by adding inorganic fillers such as glass fibers, glass particles, or ceramic particles. Furthermore, using ceramic plates or ceramic structures as part of the fixing member 344 can improve mechanical properties or insulation. Even metal materials can be used as fixing members 344 by providing an insulating coating to their surface or to areas requiring electrical insulation.

[0020] Figure 3 is a cross-sectional view of the electrical circuit 400 shown in Figures 1 and 2 along line XX. Figure 4 is a cross-sectional perspective view of the electrical circuit 400 shown in Figures 1 and 2 along line YY. Figure 5 is a cross-sectional perspective view of the electrical circuit 400 shown in Figures 1 and 2 along line XX.

[0021] As shown in Figure 3, the first semiconductor element forming the upper arm circuit of the power converter includes an active element 155 and a diode 156 (see Figures 7 and 8 described later). Si, SiC, GaN, GaO, C, etc., can be used as the active element. If the body diode of the active element 155 is used, the separate diode may be omitted. The collector side of the first semiconductor element 155 is joined to the second conductor plate 431. Solder or sintered metal may be used for this joining. The emitter side of the first semiconductor element 155 is joined to the first conductor plate 430.

[0022] As shown in Figure 4, the lower arm circuit is formed by a second semiconductor element comprising an active element 157 and a diode 158 (see Figures 7 and 8 described later). As shown in Figure 4, the collector side of the second semiconductor element 157 is bonded to the fourth conductor plate 433. The emitter side of the second semiconductor element 157 is bonded to the third conductor plate 432. The cooling members 340 are arranged on both sides of the semiconductor device 300, and the internal coolant flows through the flow path connecting section 346, circulating from one side of the cooling members 340 to the other.

[0023] The conductive plates 430, 431, 432, and 433 are not particularly limited as long as they are made of materials with high electrical and thermal conductivity, but it is desirable to use metallic materials such as copper-based or aluminum-based materials, or composite materials such as diamond, carbon, or ceramics with high thermal conductivity. These may be used alone, but they may also be plated with Ni or Ag to improve bonding with solder or sintered metals.

[0024] As shown in Figures 3, 4, and 5, the conductor plates 430, 431, 432, and 433 not only conduct electric current but also act as heat transfer members, transferring heat generated by the semiconductor elements 155, 156, 157, and 158 to the cooling member 340. The sides of the conductor plates 430, 431, 432, and 433 opposite to the sides joined to the semiconductor elements 155, 156, 157, and 158 become the heat dissipation surfaces. Since the conductor plates 430, 431, 432, and 433 and the cooling member 340 have different potentials, an insulating sheet 440 is placed between them and the heat dissipation surfaces.

[0025] The insulating sheet 440 is constructed by laminating a resin insulating layer 443 and a surface conductor layer 444. The resin insulating layer 443 covers the conductor plates 430, 431, 432, and 433 on one side and is bonded to the heat dissipation surfaces of the conductor plates 430, 431, 432, and 433. The surface conductor layer 444 is bonded to the other side of the resin insulating layer 443 and is exposed on the surface of the semiconductor device 300.

[0026] The resin insulating layer 443 of the insulating sheet 440 is not particularly limited as long as it has adhesive properties with respect to the conductive plates 430, 431, 432, and 433, but an epoxy resin-based insulating layer with dispersed powdered inorganic filler is preferable. This is because it offers a good balance between adhesion and heat dissipation. The insulating sheet 440 is provided with a surface conductive layer 444, such as metal foil, on the side that comes into contact with the heat conductive member 453 described later.

[0027] The insulating sheet 440 is cured simultaneously with the sealant 360 during the transfer molding process. When the insulating sheet 440 is mounted on the mold during the transfer molding process, a release sheet or a surface conductive layer 444 is provided on the contact surface between the insulating sheet 440 and the mold to prevent adhesion to the mold. Release sheets have poor thermal conductivity and therefore require a peeling process after transfer molding. However, if a surface conductive layer 444 such as metal foil is used, it can be used without peeling after transfer molding by selecting a metal with high thermal conductivity, such as copper or aluminum.

[0028] The semiconductor elements 155, 156, 157, 158, the conductor plates 430, 431, 432, 433, and the insulating sheet 440 are sealed with a sealing material 360 by transfer molding to constitute the semiconductor device 300.

[0029] The heat conduction member 453 is placed between the semiconductor device 300 and the cooling member 340 to reduce contact thermal resistance. The heat conduction member 453 can be a material that is fluid at room temperature or high temperature, such as grease, gel grease, or phase change sheet. However, to ensure workability and long-term reliability, a curable heat conduction material that is fluid before curing and loses its fluidity after curing is preferable. The curable heat conduction member 453 has the advantage of low viscosity and excellent workability when applied, and can improve mechanical properties after curing. Curing can be performed by heat curing, moisture curing, or UV curing, but heat curing is preferable for curing to deep layers.

[0030] The thermal conductive member 453 is a material obtained by mixing a highly thermally conductive material such as metal, ceramics, or carbon-based material with a resin. Silicon resin is most desirable as the resin because it exhibits little change in elastic modulus from around -40°C to around 200°C. Furthermore, an insulating material is preferred for the thermal conductive member 453. This is to prevent a decrease in insulation due to the material of the thermal conductive member 453 adhering near the terminals. The thermal conductivity of the thermal conductive member 453 is 5-8 W / (m·K).

[0031] The substrate 350 can be a low-cost printed circuit board, a ceramic substrate with excellent insulation and heat resistance, or a thin, flexible substrate. Alternatively, a metal plate such as a lead frame with a pattern formed and punched out, or a similar metal plate alone, can also be used as the substrate 350, as it can provide the necessary electrical connections.

[0032] The conductive layer of the substrate 350 only needs to be one or more layers for wiring, but using two or more layers increases the flexibility of the wiring layout. By forming an insulating film such as resist on the surface of the substrate 350, the insulation between adjacent terminals and wiring can be improved. Using photoresist or similar materials makes it easy to remove the resist from areas where electrical connections are required. Either a silicon-based coating agent or a fluorine-based coating agent is applied to the substrate 350.

[0033] Terminals 325 derived from semiconductor elements 155, 156, 157, and 158 are connected to the wiring of the substrate 350. Specifically, as shown in Figures 3 and 5, the upper arm gate terminal 325U is derived from the first semiconductor element 155 and connected to the wiring of the substrate 350. Furthermore, positive terminals 325P, which are integrally formed with the second conductor plate 431, are derived from the first semiconductor element 155 and the second semiconductor element 156 and connected to the wiring of the substrate 350. In addition, as shown in Figures 3 and 5, the terminals 325 derived from semiconductor elements 155, 156, 157, and 158 are formed in a V-shape in cross-section along the XX line. The V-shaped apex of the V-shaped terminal 325 abuts against the wiring of the substrate 350. The ends of the V-shaped terminal 325 abut against the support portion 345 of the fixing member 344. The pressure applied by the pressurizing member 341 is transmitted to the fixing member 344, causing the support portion 345 of the fixing member 344 to press the terminal 325 against the wiring on the circuit board 350, thereby strengthening the connection between the terminal 325 and the wiring on the circuit board 350.

[0034] Although the terminal 325 was described using an example with a V-shaped cross-section, other bent shapes are also acceptable. Furthermore, the terminal 325 has an elastic bent shape, and the support portion 345 of the fixing member 344 can easily press the bent terminal 325 against the wiring. Thus, since the terminal 325 of the semiconductor device 300 has a bent shape such as a V-shape, it forms a so-called tolerance absorption mechanism that absorbs variations in the connection position between the terminal 325 and the wiring, resulting in excellent productivity. The terminal 325 may be plated with either Au plating, Ag plating, Sn plating, or Ni plating.

[0035] According to this embodiment, the cooling member 340 is fixed and the wiring is connected by the pressurizing member 341, so compared to the case where the cooling member 340 is fixed and the wiring is connected separately, an electrical circuit body 400 with superior productivity can be provided. Furthermore, since it is not necessary to fix the cooling member 340 and connect the wiring separately, the structure of the electrical circuit body 400 can be simplified and miniaturized. In addition, since the wiring is connected by the pressure applied by the pressurizing member 341, carbon dioxide emissions during the manufacture of the electrical circuit body 400 can be reduced compared to connections by soldering or welding. Moreover, by removing the pressurizing member 341, repair and restoration of the electrical circuit body 400, such as replacing the semiconductor device 300, can be easily performed, thereby reducing the environmental impact of the product.

[0036] Figure 6 is a cross-sectional view illustrating the replacement of semiconductor device 300, etc. Similar to Figure 3, it is shown as a cross-sectional view of the electrical circuit body 400 shown in Figures 1 and 2 along line XX. As shown in Figure 6, by removing the pressurizing member 341, the fixing member 344, which integrally forms the cooling member 340, can be separated from the semiconductor device 300. At this time, the connection between the terminal 325 of the semiconductor device 300 and the wiring of the substrate 350 is also released. In other words, by removing the pressurizing member 341, the pressure of the fixing member 344, which integrally forms the cooling member 340, on the semiconductor device 300 is released, and the connection between the terminal 325 and the wiring is released. This allows, for example, an old semiconductor device 300 to be replaced with a new semiconductor device 300, or an old cooling member 340 to be replaced with a new cooling member 340.

[0037] Figure 7 is a semi-transparent plan view of the semiconductor device 300. Figure 8 is a circuit diagram of the semiconductor device 300.

[0038] As shown in Figures 7 and 8, the positive terminal 325P outputs from the collector side of the upper arm circuit and is connected to the positive side of the battery or capacitor. The upper arm gate terminal 325U outputs from the gate of the active element 155 of the upper arm circuit. The negative terminal 325M outputs from the emitter side of the lower arm circuit and is connected to the negative side of the battery or capacitor, or to GND. The lower arm gate terminal 325L outputs from the gate of the active element 157 of the lower arm circuit. The AC terminal 325A outputs from the collector side of the lower arm circuit and is connected to the motor. When neutral point grounding is performed, the lower arm circuit is connected to the negative side of the capacitor, not to GND.

[0039] The emitter sense terminal 325E of the upper arm is output from the emitter of the active element 155 of the upper arm circuit, and the emitter sense terminal 325E of the lower arm is output from the emitter of the active element 157 of the lower arm circuit. The collector sense terminal 325C of the upper arm is output from the collector of the active element 155 of the upper arm circuit, and the collector sense terminal 325C of the lower arm is output from the collector of the active element 157 of the lower arm circuit.

[0040] Furthermore, a conductive plate (upper arm circuit emitter side) 430 and a conductive plate (upper arm circuit collector side) 431 are arranged above and below the active element 155 and diode 156 of the semiconductor element (upper arm circuit). A conductive plate (lower arm circuit emitter side) 432 and a conductive plate (lower arm circuit collector side) 433 are arranged above and below the active element 157 and diode 158 of the semiconductor element (lower arm circuit).

[0041] The semiconductor device 300 in this embodiment has a 2-in-1 structure in which two arm circuits, an upper arm circuit and a lower arm circuit, are integrated into a single module. Alternatively, a structure in which multiple upper arm circuits and lower arm circuits are integrated into a single module may be used. In this case, the number of output terminals from the semiconductor device 300 can be reduced, making it smaller.

[0042] Figures 9(a), 9(b), 9(c), and 9(d) are cross-sectional views illustrating the manufacturing process of the semiconductor device 300. Similar to Figure 3, they are shown as cross-sectional views of XX lines for one module.

[0043] Figure 9(a) shows the temporary bonding process. The collector side of semiconductor element 155 and the cathode side of semiconductor element 156 are connected to the second conductor board 431, and the gate electrode, emitter sense electrode, and collector electrode of semiconductor element 155 are connected to the gate terminal 325U, emitter sense terminal 325E, and collector sense terminal 325C of the upper arm, respectively, by wire bonding. Furthermore, the emitter side of semiconductor element 155 and the anode side of semiconductor element 156 are connected to the first conductor board 430 to fabricate the circuit body 310 on the upper arm side. Similarly, the collector side of semiconductor element 157 and the cathode side of semiconductor element 158 ​​are connected to the fourth conductor board 433, and the gate electrode, emitter sense electrode, and collector electrode of semiconductor element 157 are connected to the gate terminal 325L, emitter sense terminal 325E, and collector sense terminal 325C of the lower arm, respectively, by wire bonding.

[0044] Furthermore, the emitter side of semiconductor element 157 and the anode side of semiconductor element 158 ​​are connected to the third conductor plate 432 to fabricate the lower arm circuit body 310. However, in Figure 9(a), only the upper arm circuit body 310 is shown, and the lower arm circuit body 310 is not shown. After that, insulating sheets 440 are temporarily attached to the conductor plates 430 to 433. Temporary attachment means that the insulating sheets 440 are temporarily attached using their adhesive strength, leaving room for them to harden and bond during the subsequent transfer molding process.

[0045] Figures 9(b) to 9(d) show the transfer molding process. The transfer molding apparatus 601 is equipped with a spring 602 in the mold 603. This spring 602 allows a predetermined load to be applied to the semiconductor elements 155 to 158 without applying excessive pressure, even if the height of the circuit body 310 varies. The transfer molding apparatus 601 is also equipped with a vacuum degassing mechanism (not shown). Vacuum degassing compresses voids even if the sealing material 360 made of resin or the like encases them, thereby improving insulation. Furthermore, covering the circuit body 310 with a release film (not shown) protects against resin burrs entering the spring drive unit and the like.

[0046] As shown in Figure 9(b), the circuit body 310 with the insulating sheet 440 temporarily attached is set inside the mold 603, which has been preheated to a constant temperature of 175°C. Next, as shown in Figure 9(c), the upper and lower molds 603 are clamped together. At this time, the insulating sheet 440 and the conductor plates 430-433 are pressed together by the spring 602.

[0047] Next, as shown in Figure 9(d), the sealing material 360 is injected into the mold 603. After that, the resin-sealed semiconductor device 300 is removed from the transfer molding device 601 and post-curing is performed at 175°C for more than 2 hours.

[0048] Figures 10(a) and 10(b) are cross-sectional views illustrating the manufacturing process of the electrical circuit body 400. First, following the process shown in Figure 9(d), the terminals 325 derived from semiconductor elements 155, 156, 157, and 158, such as the upper arm gate terminal 325U and the positive terminal 325P, are formed into a bent shape such as a V-shape. This forming can be done using a mold or the like.

[0049] Figure 10(a) shows the coating process. The cooling member 340 is integrally formed with the fixing member 344, and the heat conductive member 453 is applied to this cooling member 340.

[0050] Figure 10(b) shows the adhesion and curing process. The cooling member 340, to which the heat conductive member 453 has been applied, is brought into close contact with the semiconductor device 300 using the pressurizing member 341. At this time, the ends of the V-shaped terminals 325 are pressed by the support portion 345 of the fixing member 344, and the terminals 325 are connected to the wiring on the substrate 350. In other words, the pressurizing member 341 fixes the cooling member 340 and connects the terminals 325. Then, the electrical circuit body 400 is fabricated by curing the heat conductive member 453.

[0051] Figures 11(a) and 11(b) are cross-sectional views illustrating the process of integrating the fixing member 344 and the cooling member 340. As shown in Figure 11(a), a recess is formed on the inside of the fixing member 344 into which the cooling member 340 is fitted. When bonding the cooling member 340, adhesive is applied to the recess.

[0052] Next, as shown in Figure 11(b), the cooling member 340 is fitted into the recess of the fixing member 344 and bonded together, thereby integrally forming the fixing member 344 and the cooling member 340. The fixing member 344 was manufactured separately from the cooling member 340, and then the cooling member 340 was fixed by adhesive. By manufacturing them separately, the structure can be simplified and costs can be reduced.

[0053] Figures 12(a) and 12(b) are cross-sectional views illustrating the process of integrating the fixing member 344 and the cooling member 340 in modified example 1. As shown in Figure 12(a), a cavity 347 is formed in the central part of the fixing member 344. A recess is formed on the inside around the cavity 347 into which the cooling member 340 is fitted. When bonding the cooling member 340, adhesive is applied to the recess.

[0054] Next, as shown in Figure 12(b), the cooling member 340 is fitted into the recess of the fixing member 344 and bonded together, thereby integrally forming the fixing member 344 and the cooling member 340. In this modified example 1, the material required for the fixing member 344 can be reduced.

[0055] Figures 13(a) and 13(b) are cross-sectional views illustrating the process of integrating the fixing member 344 and the cooling member 340 in modified example 2. As shown in Figure 13(a), a cavity 347 is formed in the central part of the fixing member 344. A recess is formed on the inside of the cavity 347 into which the cooling member 340 is fitted, and furthermore, engaging projections 349 are formed on the inside of the cavity 347 at predetermined locations around it. Engaging holes 342 are formed in the cooling member 340 corresponding to the positions of the engaging projections 349.

[0056] Next, as shown in Figure 13(b), the fixing member 344 and the cooling member 340 are integrally formed by engaging the engaging projection 349 of the fixing member 344 with the engaging hole 342 of the cooling member 340. Alternatively, the fixing member 344 and the cooling member 340 may be integrally formed by forming an engaging hole in the fixing member 344 and an engaging projection in the cooling member 340 and engaging them. In this modified example 2, the fixing member 344 and the cooling member 340 can be integrally formed without using adhesive, and the fixing member 344 or the cooling member 340 can be replaced by releasing the engagement.

[0057] Figures 14(a), 14(b), 14(c), 14(d), and 14(e) are cross-sectional views showing modified examples 3, 4, 5, 6, and 7 of the electrical circuit body 400, respectively. Similar to Figure 3, the cross-sectional view is shown for XX lines per module. The same reference numerals are used for parts identical to those in Figure 3, and the explanation is simplified.

[0058] Modified example 3 shown in Figure 14(a) includes a connecting pin 348 that connects the terminal 325 to the wiring on the substrate 350, and the support portion 345 of the fixing member 344 supports the connecting pin 348. Specifically, both ends of the connecting pin 348 are held by the support portions 345 of the fixing member 344, which are arranged on both sides of the semiconductor device 300, and the wiring on the terminal 325 and the substrate 350 is electrically connected to the connecting pin 348 between them. The connecting pin 348 is, for example, an elastic contact such as a press-fit, and is press-fitted into the through-holes formed in the terminal 325 and the substrate 350. The connecting pin 348 has an enlarged portion that is larger than the diameter of the through-hole and longer than the thickness of the terminal 325 and the substrate 350, so that tolerances can be absorbed even if the dimensions of the parts vary. In addition, by increasing the diameter of the through-hole and the diameter of the enlarged portion on the side closer to the insertion direction in accordance with the insertion direction of the connecting pin 348, the connecting pin 348 can be inserted smoothly.

[0059] In the modified example 4 shown in Figure 14(b), the terminal 325 is bent into a U-shape, and the support portion 345 of the fixing member 344 presses the terminal 325 against the wiring on the substrate 350. The tip of the U-shaped bent terminal 325 is electrically connected to the wiring on the substrate 350. The terminal 325 has an elastic bendable shape, and the support portion 345 of the fixing member 344 can easily press the bent terminal 325 against the wiring.

[0060] In the modified example 5 shown in Figure 14(c), the support portion 345 of the fixing member 344 includes an elastic member, which presses the substrate 350 against the terminal 325. Specifically, the tip of the U-shaped bent terminal 325 is electrically connected to the wiring of the substrate 350, and the opposite side of the substrate 350 is pressed by an elastic member 343, such as a spring, held by the support portion 345 of the fixing member 344. On the opposite side of the substrate 350 with the terminal 325 in between, the terminal 325 is held by a sealing material 360. As a result, the substrate 350 flexes towards the terminal 325, strengthening the connection between the terminal 325 and the wiring of the substrate 350, and the elastic member 343 can absorb tolerances even if the dimensions of the components vary.

[0061] In the modified example 6 shown in Figure 14(d), the support portion 345 of the fixing member 344 includes an elastic member 343, which presses the terminal 325 against the wiring on the substrate 350. Specifically, the tip of the terminal 325 is electrically connected to the wiring on the substrate 350, and the tip of the terminal 325 is pressed toward the substrate 350 by an elastic member 343, such as a spring, held by the support portion 345 of the fixing member 344. As a result, the terminal 325 is pressed toward the substrate 350, strengthening the connection between the terminal 325 and the wiring on the substrate 350, and the elastic member 343 can absorb tolerances even if the dimensions of the parts vary.

[0062] In the modified example 7 shown in Figure 14(e), the substrate 350 includes a clamping portion 351 made of parallel plates that clamp the terminal 325. Specifically, the tip portion of the terminal 325 is inserted between the parallel plates of the clamping portion 351 provided on the substrate 350. The parallel plates may be conductive, and the terminal 325 clamped between the parallel plates is electrically connected to the wiring. Even if the position of the inserted terminal varies in the direction parallel to the parallel plates, the tolerance can be absorbed.

[0063] Figure 15 is a cross-sectional view showing a modified example 8 of the electrical circuit body 400. Similar to Figure 3, it is shown as a cross-sectional view of XX lines for one module. The same reference numerals are used for parts that are the same as in Figure 3, and the explanation is simplified.

[0064] As shown in Figure 15, the substrate 350 has a recess 352 formed to receive the terminal 325. Specifically, a recess 352 with wiring is formed in the area where the terminal 325 and the wiring of the substrate 350 come into contact, and the contact portion of the terminal 325 is positioned in this recess 352. This prevents misalignment of the contact position between the terminal 325, which is pressed by the support portion 345 of the fixing member 344, and the wiring, and also allows tolerances to be absorbed even if the dimensions of the components vary.

[0065] Figure 16 is a plan view of the electrical circuit 400 in a comparative example. This comparative example is an example to which this embodiment is not applied, and is a figure for comparison with this embodiment. Similar to Figure 1, it is a plan view of the electrical circuit 400, and the same reference numerals are used for the same parts as in Figure 1 for a simplified explanation.

[0066] In the comparative example, as shown in Figure 16, there is a screw portion 355 for fixing the fixing member 344 into which the cooling member 340 is integrally formed, and a screw portion 356 for electrically connecting the terminals of the semiconductor device 300. Therefore, since it is necessary to fix the cooling member 340 and connect the wiring separately, the productivity of the electrical circuit body 400 decreases. In addition, the structure of the electrical circuit body 400 becomes larger because separate configurations are required for fixing the cooling member 340 and connecting the wiring. Furthermore, if the wiring is connected by soldering or welding, carbon dioxide emissions during manufacturing increase, making it impossible to replace old semiconductor devices 300 with new ones, and making it difficult to repair and restore the electrical circuit body 400, thus increasing the environmental burden of the product.

[0067] Figure 17 is a circuit diagram of a power converter 200 using a semiconductor device 300. The power converter 200 comprises inverter circuit sections 140 and 142, an auxiliary inverter circuit section 43, and a capacitor module 500. The inverter circuit sections 140 and 142 each contain multiple semiconductor devices 300, which are connected to form a three-phase bridge circuit. When the current capacity is large, the semiconductor devices 300 can be further connected in parallel, and these parallel connections can be made corresponding to each phase of the three-phase inverter circuit to accommodate the increased current capacity. In addition, the current capacity can be increased by connecting in parallel the semiconductor elements 155 and 157 and diodes 156 and 158, which are semiconductor elements built into the semiconductor devices 300.

[0068] Inverter circuit section 140 and inverter circuit section 142 have the same basic circuit configuration, and their control methods and operations are also basically the same. Since the general outline of the circuit operation of inverter circuit section 140, etc., is well known, a detailed explanation will be omitted here.

[0069] The upper arm circuit includes an active element 155 and an upper arm diode 156 as switching semiconductor elements, while the lower arm circuit includes an active element 157 and a lower arm diode 158 as switching semiconductor elements. The active elements 155 and 157 receive drive signals output from one or the other of the two driver circuits constituting the driver circuit 174 and perform switching operations to convert the DC power supplied from the battery 136 into three-phase AC power.

[0070] The active element 155 for the upper arm and the active element 157 for the lower arm are equipped with a collector electrode, an emitter electrode, and a gate electrode. The diode 156 for the upper arm and the diode 158 for the lower arm are equipped with two electrodes: a cathode electrode and an anode electrode. As shown in Figure 8, the cathode electrodes of diodes 156 and 158 are electrically connected to the collector electrodes of active elements 155 and 157, and the anode electrodes are electrically connected to the emitter electrodes of active elements 155 and 157. As a result, the current flow from the emitter electrode to the collector electrode of the active element 155 for the upper arm and the active element 157 for the lower arm is in the forward direction. The active elements 155 and 157 are, for example, IGBTs.

[0071] Alternatively, a MOSFET (metal oxide semiconductor field-effect transistor) may be used as the active element; in this case, the diode 156 for the upper arm and the diode 158 for the lower arm are not required.

[0072] The positive terminal 325P and negative terminal 325M of each upper and lower arm series circuit are connected to the DC terminals for capacitor connection of the capacitor module 500, respectively. AC power is generated at the connection point between the upper and lower arm circuits, and the connection point between the upper and lower arm circuits of each upper and lower arm series circuit is connected to the AC terminal 325A of each semiconductor device 300. The AC terminal 320B of each semiconductor device 300 for each phase is connected to the AC output terminal of the power converter 200, and the generated AC power is supplied to the stator winding of the motor generator 192 or 194.

[0073] The control circuit 172 generates timing signals to control the switching timing of the active element 155 for the upper arm and the active element 157 for the lower arm based on input information from the vehicle's control device and sensors (e.g., current sensor 180). The driver circuit 174 generates drive signals to switch the active element 155 for the upper arm and the active element 157 for the lower arm based on the timing signals output from the control circuit 172. Note that 181 and 188 are connectors.

[0074] The upper and lower arm series circuit includes a temperature sensor (not shown), and temperature information from the upper and lower arm series circuit is input to the microcontroller. The microcontroller is also input voltage information from the DC positive terminal side of the upper and lower arm series circuit. Based on this information, the microcontroller performs over-temperature detection and over-voltage detection. If over-temperature or over-voltage is detected, the microcontroller stops the switching operation of all active elements 155 for the upper arm and 157 for the lower arm, protecting the upper and lower arm series circuit from over-temperature or over-voltage.

[0075] Figure 18 is an external perspective view of the power converter 200 shown in Figure 17, and Figure 19 is a cross-sectional perspective view of the power converter 200 shown in Figure 18 along the line XV-XV.

[0076] The power converter 200 is comprised of a lower case 11 and an upper case 10, and has a housing 12 formed in a substantially rectangular parallelepiped shape. Inside the housing 12 are an electrical circuit 400, a capacitor module 500, and the like. The electrical circuit 400 has a cooling channel that flows to a cooling member 340, and a refrigerant inlet pipe 13 and a refrigerant outlet pipe 14 that communicate with the cooling channel protrude from one side of the housing 12. The upper side of the lower case 11 is open, and the upper case 10 is attached to the lower case 11, closing the opening of the lower case 11. The upper case 10 and the lower case 11 are formed from an aluminum alloy or the like and are sealed and fixed to the outside. The upper case 10 and the lower case 11 may be configured as a single unit. The housing 12 has a simple rectangular parallelepiped shape, which makes it easy to attach to vehicles and the like, and also makes it easier to manufacture.

[0077] A connector 17 is attached to one longitudinal side of the housing 12, and an AC terminal 18 is connected to this connector 17. In addition, a connector 21 is provided on the side from which the refrigerant inlet pipe 13 and refrigerant outlet pipe 14 are routed.

[0078] As shown in Figure 19, an electrical circuit 400 is housed inside the housing 12. The electrical circuit 400 contains a control circuit 172 and a driver circuit 174, and a capacitor module 500 is housed on the DC terminal side of the electrical circuit 400. By positioning the capacitor module at the same height as the electrical circuit 400, the power converter 200 can be made thinner, improving the flexibility of installation in the vehicle. The AC terminal 325A of the electrical circuit 400 is connected to the connector 188, passing through the current sensor 180. In addition, the DC terminals of the semiconductor device 300, the positive terminal 325P and the negative terminal 325M, are connected to the positive and negative terminals 362A and 362B of the capacitor module 500, respectively.

[0079] According to the embodiments described above, the following effects and advantages can be obtained. (1) The electrical circuit body 400 comprises a semiconductor device 300 formed by sealing semiconductor elements 155, 156, 157, and 158 with a sealing material 360, from which terminals 325 are led out from the semiconductor elements 155, 156, 157, and 158; a substrate 350 equipped with wiring to which the terminals 325 are connected; a cooling member 340 positioned opposite the semiconductor device 300 to cool the heat generated by the semiconductor elements 155, 156, 157, and 158; a fixing member 344 for fixing the cooling member 340 to the semiconductor device 300; and a pressurizing member 341 that pressurizes the fixing member 344 in a direction that causes the cooling member 340 to be in close contact with the semiconductor device 300. The fixing member 344 includes a support portion 345 that supports the connection between the terminals 325 and the wiring by the pressure transmitted from the pressurizing member 341. This makes it possible to provide an electrical circuit body with excellent productivity for the device.

[0080] The present invention is not limited to the embodiments described above, and other forms 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 features of the present invention. Furthermore, configurations combining the above embodiments with multiple modifications are also possible. [Explanation of symbols]

[0081] 10...Upper case, 11...Lower case, 13...Refrigerant inlet pipe, 14...Refrigerant outlet pipe, 17, 21, 181, 182, 188...Connectors, 18...AC terminals, 43, 140, 142...Inverter circuits, 155, 156, 157, 158...Semiconductor elements, 172...Control circuit, 174...Driver circuit, 180...Current sensors, 192, 194...Motor generators, 200...Power converters, 300...Semiconductor devices, 310...Circuit assembly, 325P...Positive terminal, 325M...Negative terminal, 325A...AC terminal, 325C...Collector sense terminal, 325L...Lower arm gate terminal, 325E...Emit Tassens terminal, 325U... Upper arm gate terminal, 340... Cooling member, 341... Pressurizing member, 342... Engagement hole, 343... Elastic member, 344... Fixing member, 345... Support part, 347... Cavity, 348... Connecting pin, 349... Engagement projection, 350... Substrate, 351... Clamping part, 352... Recess, 355, 356... Screw part, 360... Sealing material, 400... Electrical circuit body, 430, 431, 432, 433... Conductor plate, 440... Insulating sheet, 443... Resin insulating layer, 444... Surface conductor layer, 453... Thermal conductive member, 500... Capacitor module, 601... Transfer molding device, 602... Spring.

Claims

1. A semiconductor device comprising a semiconductor element sealed with a sealing material, having a pair of main surfaces and a pair of side surfaces from which terminals from the semiconductor element are respectively led, A circuit board having wiring to which the aforementioned terminals are connected, A first cooling member is provided, which is positioned on one of the pair of main surfaces facing the semiconductor device and which cools the heat generated by the semiconductor element. A second cooling member is positioned on the other side of the pair of main surfaces facing the semiconductor device, and is used to cool the heat generated by the semiconductor element. A first fixing member for fixing the first cooling member to the semiconductor device, A second fixing member is integrally configured with the second cooling member and fixes the second cooling member to the semiconductor device, The device comprises a pressurizing member that applies pressure to the first and second fixing members in a direction that causes the first and second cooling members to be in close contact with the semiconductor device, The first fixing member is an electrical circuit body that includes a support portion which presses the terminal against the wiring of the substrate placed on the second fixing member by the pressure transmitted from the pressurizing member, thereby supporting the connection between the terminal and the wiring, and also bringing the substrate into close contact with the second fixing member via the terminal.

2. In the electrical circuit described in claim 1, The terminal has an elastic, bendable shape, and the support portion is an electrical circuit body that presses the bendable terminal against the wiring.

3. In the electrical circuit described in claim 1, The support portion includes an elastic member, and the elastic member presses the terminal against the wiring on the substrate.

4. In the electrical circuit described in claim 1, The support portion includes an elastic member, and the elastic member presses the substrate against the terminals in an electrical circuit body.

5. In the electrical circuit described in claim 1, The substrate is an electrical circuit body having a clamping portion for clamping the terminals.

6. In the electrical circuit described in claim 1, The substrate is an electrical circuit body having recesses for receiving the terminals.

7. In the electrical circuit body according to any one of claims 1 to 6, An electrical circuit body in which the first cooling member and the first fixing member, and the second cooling member and the second fixing member are integrally formed by adhesion or engagement.

8. In the electrical circuit body according to any one of claims 1 to 6, An electrical circuit body comprising heat conductive members disposed between the semiconductor device and the first and second cooling members, respectively.

9. In the electrical circuit body according to claim 8, The thermal conductivity of the heat-conducting member is 5 to 8 W / (m·K) in this electrical circuit body.

10. In the electrical circuit body according to any one of claims 1 to 6, The terminals of the semiconductor device are plated with either Au plating, Ag plating, Sn plating, or Ni plating. An electrical circuit body on which either a silicon-based coating agent or a fluorine-based coating agent is applied to the substrate.

11. In the electrical circuit body according to any one of claims 1 to 6, An electrical circuit in which, upon removal of the pressurizing member, the pressing of the first and second fixing members against the semiconductor device, and the connection between the terminals and the wiring, are released.

12. In the electrical circuit body according to any one of claims 1 to 6, The first and second cooling members are connected to each other via a flow path connecting portion. An electrical circuit in which a refrigerant flows from one of the first and second cooling members to the other through the aforementioned flow path connecting portion.

13. A power conversion device comprising an electrical circuit body according to any one of claims 1 to 6, which converts DC power to AC power.

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