Electrical circuit bodies and power converters

Abstract

To solve the problem that a countermeasure against outflow of a heat conductive member is not considered, and reliability of a device is lowered.SOLUTION: An electric circuit body includes a semiconductor device which incorporates a semiconductor element and has a heat radiation part for the semiconductor element formed on at least one surface thereof, a cooling member which is arranged so as to face the radiation part of the semiconductor device and cools heat generation by the semiconductor element, a heat conductive member arranged between the semiconductor device and the cooling member, and a resin member which is arranged between the semiconductor device and the cooling member and outside a projection region of the radiation part in a lamination direction of the semiconductor device and the cooling member so as to be brought into close contact with the heat conductive member, wherein the resin member has a compression set smaller than that of the heat conductive member.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] Power conversion devices that operate by switching actions of semiconductor elements are widely used in consumer applications, in-vehicle applications, railway applications, substation facilities and the like due to their high conversion efficiency. Semiconductor elements generate heat when energized. For this reason, a cooling member for cooling the semiconductor element is provided, and further, a heat conductive member is disposed between the semiconductor device incorporating the semiconductor element and the cooling member arranged to face the semiconductor device. This heat conductive member conducts heat generated from the semiconductor element to the cooling member by bringing the semiconductor device and the cooling member into close contact with each other. Cooling of semiconductor devices is required to have high reliability for maintaining heat dissipation performance, particularly in in-vehicle applications.

[0003] Patent Document 1 discloses an inverter including a housing in which an accommodation portion for accommodating a power card having both surfaces of a semiconductor element sandwiched between heat dissipation plates and a circulation path portion for circulating a cooling medium around the power card are formed, wherein a technique is disclosed in which a gap between the power card and the accommodation portion is filled with an insulating resin, and the insulating resin is cured to fix the power card.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0005] Patent Document 1 does not take measures against problems such as outflow of the heat conductive member into consideration, which reduces the reliability of the device.

Means for Solving the Problems

[0006] The electrical circuit body according to the present invention comprises a semiconductor device having a semiconductor element built in and a heat dissipation portion for the semiconductor element formed on at least one side; a cooling member disposed opposite to the heat dissipation portion of the semiconductor device and for cooling the heat generated by the semiconductor element; a heat conductive member disposed between the semiconductor device and the cooling member; and a resin member disposed between the semiconductor device and the cooling member, outside the projection region of the heat dissipation portion in the stacking direction of the semiconductor device and the cooling member, and in close contact with the heat conductive member, wherein the resin member has a smaller compression set than the heat conductive member. Furthermore, the pressure applied to the cooling member against the semiconductor device is shared between the heat conductive member and the resin member, with the load shared by the resin member being greater than that shared by the heat conductive member. [Effects of the Invention]

[0007] According to the present invention, it is possible to suppress the outflow of heat conductive material and provide a highly reliable device. [Brief explanation of the drawing]

[0008] [Figure 1] This is a plan view of an electrical circuit according to an embodiment. [Figure 2] This is a cross-sectional view of the electrical circuit body along line XX. [Figure 3] This is a cross-sectional perspective view of the electrical circuit along the YY line. [Figure 4] This is a cross-sectional perspective view of an electrical circuit along line XX. [Figure 5] This is a semi-transparent plan view of a semiconductor device. [Figure 6] This is a circuit diagram of a semiconductor device. [Figure 7] (a)(b)(c)(d) These are cross-sectional views illustrating the manufacturing process of semiconductor devices. [Figure 8] (a)(b) These are cross-sectional views illustrating the manufacturing process of an electrical circuit. [Figure 9] (a)(b)(c) These are cross-sectional views illustrating the plastic deformation of the heat-conducting member according to the comparative example. [Figure 10] (a)(b)(c) These are cross-sectional views illustrating the plastic deformation of the heat-conducting member according to the embodiments. [Figure 11](a)(b)(c)(d) These are plan views showing the arrangement of resin components. [Figure 12] (a)(b) Cross-sectional views showing embodiments and comparative examples of electrical circuit bodies. [Figure 13] This is a circuit diagram of a power conversion device using semiconductor equipment. [Figure 14] This is a perspective view of the power converter. [Figure 15] This is a cross-sectional perspective view of a power conversion device. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below with reference to the drawings. The following description and drawings are illustrative for illustrating the present invention, and have been omitted and simplified as appropriate for clarity of explanation. The present invention can also be carried out in various other forms. Unless otherwise specified, each component may be singular or plural.

[0010] The positions, sizes, shapes, and ranges of the components shown in the drawings may not represent their actual positions, sizes, shapes, and ranges in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, and ranges disclosed in the drawings.

[0011] Figure 1 is a plan view of an electrical circuit body 400 according to an embodiment. The electrical circuit 400 consists of a semiconductor device 300 and a cooling member 340. In the example shown in Figure 1, the electrical circuit 400 is made up of three semiconductor devices 300 arranged in parallel.

[0012] The semiconductor device 300 incorporates semiconductor elements 155 and 157, which will be described later, sealed with a sealing material 360. Both surfaces of these semiconductor elements 155 and 157 are formed with heat dissipation portions that dissipate heat generated by the switching operation of the semiconductor elements 155 and 157. Further, in the semiconductor device 300, terminals connected to the semiconductor elements 155 and 157 are led out from the sealing material 360 on the side surface of the semiconductor device 300. These terminals are power terminals through which a large current flows, such as a positive electrode side terminal 315B and a negative electrode side terminal 319B connected to the capacitor module 500 (see FIG. 13) of the DC circuit, and an AC side terminal 320B connected to the motor generators 192 and 194 (see FIG. 13) of the AC circuit. The terminals led out from the sealing material 360 on the side surface of the semiconductor device 300 are terminals such as a lower arm gate terminal 325L, a collector sense terminal 325C, an emitter sense terminal 325E, and an upper arm gate terminal 325U. The electric circuit body 400 in which three semiconductor devices 300 are provided in parallel functions as a power conversion device that converts a direct current and an alternating current by the switching operation of the semiconductor elements 155 and 157. Note that the number of semiconductor devices 300 included in the electric circuit body 400 is not limited to three, and may be arbitrarily set according to various forms of the electric circuit body 400.

[0013] The cooling member 340 is disposed to face the heat dissipation portion of the semiconductor device 300, and cools heat generated by the switching operation of the semiconductor elements 155 and 156. Specifically, the cooling member 340 has a flow path formed therein through which a coolant flows, and the coolant flowing through the flow path cools the heat generated by the semiconductor device 300. As the coolant, water, an antifreeze solution obtained by mixing ethylene glycol into water, or the like can be used. The cooling member 340 is preferably made of an aluminum-based material having high thermal conductivity and light weight. It is manufactured by extrusion molding, forging, brazing, or the like.

[0014] FIG. 2 is a cross-sectional view taken along line X-X of the electric circuit body 400 shown in FIG. 1, and FIG. 3 is a cross-sectional perspective view taken along line Y-Y of the electric circuit body 400 shown in FIG. 1. FIG. 4 is a cross-sectional perspective view taken along line X-X of the electric circuit body 400 shown in FIG. 1, and shows the semiconductor device 300 with the cooling member 340 and the heat conductive member 453 removed from the electric circuit body 400.

[0015] As shown in Figure 2, the electrical circuit body 400 is equipped with a pressurizing mechanism 341 that pressurizes the cooling members 340 provided on both sides of the semiconductor device 300 by sandwiching them from both sides. The pressurizing mechanism 341, although simplified in the illustration, is a mechanism that, for example, connects the cooling members 340 on both sides to each other with screws or the like and applies pressure to the semiconductor device 300 side.

[0016] As shown in Figure 2, the first semiconductor element forming the upper arm circuit of the power converter includes an active element 155 and a diode 156 (see Figures 5 and 6 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.

[0017] As shown in Figure 3, the lower arm circuit is formed by a second semiconductor element comprising an active element 157 and a diode 158 (see Figures 5 and 6 described later). As shown in Figure 3, 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.

[0018] 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.

[0019] As shown in Figures 2, 3, and 4, the conductive 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. Since the conductive plates 430, 431, 432, and 433 and the cooling member 340 have different potentials, it is desirable to use insulating sheets 440 and 441 between them.

[0020] The resin insulating layer 443 of the insulating sheets 440 and 441 is not particularly limited as long as it has adhesive properties to the heat sink, 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 sheets 440 and 441 may consist of the resin insulating layer 443 alone, but it is preferable to provide a metal foil 444 on the side that comes into contact with the heat conductive member 453 described later. The insulating sheets 440 and 441 are cured simultaneously with the sealing material 360 in the transfer molding process. When mounting the insulating sheets 440 and 441 to the mold in the transfer molding process, a release sheet or metal foil 444 is provided on the contact surface between the insulating sheets 440 and 441 and the mold to prevent adhesion to the mold. Release sheets have poor thermal conductivity, so a peeling process is required after transfer molding, but if metal foil 444 is used, it can be used without peeling after transfer molding by selecting a metal with high thermal conductivity such as copper or aluminum.

[0021] The semiconductor elements 155, 156, 157, 158, the conductor plates 430, 431, 432, 433, and the insulating sheets 440, 441 are sealed with a sealing material 360 by transfer molding to constitute the semiconductor device 300.

[0022] As shown in Figure 2, a heat conductive member 453 is placed between the semiconductor device 300 and the cooling member 340 to reduce the contact thermal resistance between them. Furthermore, a resin member 454 is placed between the semiconductor device 300 and the cooling member 340, outside the projection region 460 of the heat dissipation portion in the stacking direction of the semiconductor device 300 and the cooling member 340, in close contact with the heat conductive member 453.

[0023] The heat conduction member 453 is a curable resin product that is fluid in its uncured state and loses its fluidity after curing, in order to ensure workability and long-term reliability. Curable resin products have 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 a deep level. The heat conduction member 453 needs to be kept in close contact with the semiconductor device 300 and the cooling member 340, which have different coefficients of thermal expansion, so it is necessary to keep the stress low. For this reason, the Young's modulus of the heat conduction member 453 is preferably 50 MPa or less. The Young's modulus in this embodiment is the value measured in a dynamic viscoelasticity test in the tensile or compressive direction at a frequency of 10 Hz, a strain of 0.1%, and a temperature of 25°C.

[0024] The heat conductive member 453 is a material made by mixing a filler with resin. The most desirable resin is a silicone resin that exhibits little change in elastic modulus from around -40°C to around 200°C. The filler is a highly thermally conductive material such as metal, ceramics, or carbon-based material. Because the elastic modulus of the heat conductive member 453 is lowered by filling the resin with the filler, it becomes a cured product that is prone to plastic deformation and has a large compression set. In this embodiment, the compression set is the strain remaining 30 minutes after applying a 10% compressive displacement at room temperature for 30 minutes and then unloading.

[0025] The resin component 454 is a curable resin product that is fluid in its uncured state and loses its fluidity after curing, for ease of workability and heat dissipation. When applied, the curable resin product has low viscosity and excellent workability. Furthermore, under pressure, it can be thinned to the same thickness as the heat conduction component 453 and, upon curing, can function as a spacer between the semiconductor device 300 and the cooling component 340. Therefore, compared to the case where a spacer of a fixed thickness is used, the heat conduction component 453 can be made thinner, improving heat dissipation. This point will be discussed later with reference to Figure 12.

[0026] It is desirable that the Young's modulus of the resin member 454 is higher than that of the heat conduction member 453. The resin member 454 is positioned outside the projection region 460 in close contact with the heat conduction member 453, but the stress between the semiconductor device 300 and the cooling member 340 is set to be higher than that of the heat conduction member 453 to suppress plastic deformation of the heat conduction member 453.

[0027] The resin member 454 may be made of a resin such as silicone resin alone, or it may be a material in which a filler is mixed with this resin. In either case, the cured product shall have a smaller compression set than the heat conduction member 453. Since the resin member 454 has a smaller compression set than the heat conduction member 453, it can share the pressure applied by the pressurizing mechanism 341 to press the cooling member 340 against the semiconductor device 300, thereby preventing the heat conduction member 453 from plastically deforming and flowing out of the semiconductor device 300. In other words, the resin member 454 is set so that its load sharing is greater than that of the heat conduction member 453. This point will be discussed later with reference to Figure 10.

[0028] The resin member 454 is positioned outside the projection region 460 of the heat dissipation section in the stacking direction of the semiconductor device 300 and the cooling member 340, as shown in Figure 4. This allows heat from the semiconductor elements 155-158 to be conducted to the heat conduction member 453 without being obstructed by the resin member 454. Alternatively, the resin member 454 may be positioned outside the projection region 461 of the conductor plates 430, 431, 432, and 433 in the stacking direction of the semiconductor device 300 and the cooling member 340. This allows heat conducted from the semiconductor elements 155 and 156 through the conductor plates 430, 431, 432, and 433 to be conducted to the heat conduction member 453 without being obstructed by the resin member 454. In either case, by using a material in which a filler, which is a highly thermally conductive material, is mixed with the resin, the heat conduction of the resin member 454 will be less than that of the heat conduction member 453, but it will not significantly obstruct heat conduction. Furthermore, in all cases, the filler and the like are blended so that the Young's modulus of the resin member 454 is higher than that of the heat conductive member 453.

[0029] Figure 5 is a semi-transparent plan view of the semiconductor device 300. Figure 6 is a circuit diagram of the semiconductor device 300. As shown in Figures 5 and 6, the positive terminal 315B 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 319B 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 320B 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.

[0030] 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.

[0031] 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).

[0032] 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.

[0033] Figures 7(a), 7(b), 7(c), and 7(d) are cross-sectional views illustrating the manufacturing process of the semiconductor device 300. Similar to Figure 2, they are shown as cross-sectional views of XX lines for one module.

[0034] Figure 7(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.

[0035] 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 7(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 and 441 are temporarily attached to the conductor plates 430 to 433. Temporary attachment means that the insulating sheets 440 and 441 are temporarily attached using their adhesive strength, leaving room for them to harden and bond during the subsequent transfer molding process.

[0036] Figures 7(b) to 7(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.

[0037] As shown in Figure 7(b), the circuit body 310 with insulating sheets 440 and 441 temporarily attached is set in a mold 603 that has been preheated to a constant temperature of 175°C. Next, as shown in Figure 7(c), the upper and lower molds 603 are clamped together. At this time, the insulating sheets 440 and 441 and the conductor plates 430 to 433 are pressed together by the spring 602. The conductor plates 431 and 433 located on the collector side are pressed towards the lower mold 603 when the terminal portions on the outer circumference of the conductor plates 431 and 433 are clamped by the mold, and this is added to the force of the spring 602, so they are pressed against the insulating sheet 441 with a stronger force than the conductor plates 430 and 432 located on the emitter side.

[0038] Next, as shown in Figure 7(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 apparatus 601 and post-curing is performed at 175°C for more than 2 hours.

[0039] Figures 8(a) and 8(b) are cross-sectional views illustrating the manufacturing process of the electrical circuit body 400. This process is carried out using the semiconductor device 300 manufactured by the process shown in Figure 7(d). Figure 8(a) shows the coating process. The heat conductive member 453 and the resin member 454 are applied to the cooling member 340. The application locations and other details will be described later with reference to Figure 11.

[0040] Figure 8(b) shows the adhesion and curing process. The cooling member 340, coated with the heat conductive member 453 and the resin member 454, is brought into close contact with the semiconductor device 300. Then, the electrical circuit body 400 is fabricated by curing the heat conductive member 453 and the resin member 454.

[0041] Figures 9(a), 9(b), and 9(c) are cross-sectional views illustrating the plastic deformation of the heat conduction member 453 in a comparative example. This comparative example is a case where this embodiment is not applied.

[0042] As shown in Figure 9(a), the heat conductive member 453 is pressurized by the pressurizing mechanism 341 and is in close contact with the semiconductor device 300.

[0043] As shown in Figure 9(b), when semiconductor elements 155 and 156 generate heat due to current flow, the temperature of the conductive plate 430 bonded to the semiconductor elements 155 and 156 rises, causing localized thermal expansion towards the cooling member 340 in the direction of arrow A, centered on the projection region 460 of the heat dissipation section. As a result, the heat conduction member 453 is locally compressed and plastically deformed, being pushed out to the outside B of the projection region 460.

[0044] As shown in Figure 9(c), when the current to the semiconductor elements 155 and 156 is stopped and the conductor plate 430 cools, the local thermal expansion of the conductor plate 430 returns to its original state. The portion of the heat conduction member 453 that has undergone plastic deformation cannot bear the pressure C of the pressurizing mechanism 341 because the compressive stress decreases due to the plastic deformation. Therefore, the pressure C of the pressurizing mechanism 341 increases against the heat conduction member 453 outside the projection region 460 that has not undergone plastic deformation. As a result, the heat conduction member 453 outside the projection region 460 undergoes plastic deformation, and the heat conduction member 453 flows out to the outside D of the semiconductor device 300, reducing the thickness of the heat conduction member 453. Furthermore, repeated outflow reduces the density of the filler material inside the heat conduction member 453, reducing the heat dissipation performance of the heat conduction member 453. In addition, there is a concern that the insulation performance may decrease if the outflowed heat conduction member 453 comes into contact with terminals or other components leading out from the semiconductor device 300.

[0045] Figures 10(a), 10(b), and 10(c) are cross-sectional views illustrating the plastic deformation of the heat conduction member 453 according to this embodiment.

[0046] As shown in Figure 10(a), the heat conductive member 453 and the resin member 454 are pressurized by the pressurizing mechanism 341 and are in close contact with the semiconductor device 300.

[0047] As shown in Figure 10(b), when semiconductor elements 155 and 156 generate heat due to current flow, the temperature of the conductive plate 430 bonded to the semiconductor elements 155 and 156 rises, causing localized thermal expansion towards the cooling member 340 in the direction of arrow A, centered on the projection region 460 of the heat dissipation section. As a result, the heat conduction member 453 is locally compressed and plastically deformed, attempting to move outwards B from the projection region 460. However, since the resin member 454, which has a smaller permanent compression strain than the heat conduction member 453, is located between the semiconductor device 300 and the cooling member 340 and outside the projection region 460 of the heat dissipation section, the force that causes the heat conduction member 453 to move outwards B is pushed back in the direction of arrow E by the repulsive force of the resin member 454, thereby suppressing this movement.

[0048] As shown in Figure 10(c), when the current to the semiconductor elements 155 and 156 is stopped and the conductor plate 430 cools, the local thermal expansion of the conductor plate 430 returns to its original state. The portion of the heat conduction member 453 that has undergone plastic deformation does not share the pressurizing force of the pressurizing mechanism 341 due to the plastic deformation, so the pressurizing force applied to the heat conduction member 453 outside B of the projection region 460 increases. However, since the resin member 454 has a smaller permanent compression strain than the heat conduction member 453, the resin member 454 shares this pressurizing force as indicated by arrow F. In other words, the resin member 454 shares the pressurizing force because its load sharing is set to be greater than that of the heat conduction member 453. This makes it possible to suppress the reduction in the thickness of the heat conduction member 453. Since the thickness of the heat conduction member 453 does not change, large-scale movement or leakage of the heat conduction member 453 can be prevented. This suppresses a decrease in heat dissipation performance. Furthermore, by positioning this resin member 454 on the terminal side of the semiconductor device 300, it is possible to suppress and prevent the heat conductive member 453 from flowing out of the semiconductor device 300 and reaching the terminals, etc.

[0049] Figures 11(a), 11(b), 11(c), and 11(d) are plan views showing the arrangement of the resin members 454. In each of these figures, the arrangement of the resin members 454 is shown in the semi-transparent plan view of the semiconductor device 300 shown in Figure 5. Figure 11(a) shows an embodiment, Figure 11(b) shows modification 1, Figure 11(c) shows modification 2, and Figure 11(d) shows modification 3. In these figures, the heat conductive member 453 is shown in a transparent state.

[0050] As shown in Figure 11(a), in this embodiment, the resin member 454 is arranged in a strip shape, surrounding the outer circumference of the heat conduction member 453 and in close contact with it. The resin member 454 is positioned outside the projection area 461 of the conductor plates 430, 431, 432, and 433. Note that the resin member 454 only needs to be positioned outside the projection area 460 of the heat dissipation section. The load sharing by the resin member 454 has the effect of suppressing the outflow of the heat conduction member 453. In addition, the resin member 454 has the effect of preventing outflow by surrounding the heat conduction member 453. Normally, the resin member 454 has a lower thermal conductivity than the heat conduction member 453, but by positioning it outside the projection area 460 of the heat dissipation section, the decrease in the cooling performance of the semiconductor device 300 can be suppressed. Furthermore, by positioning the resin member 454 outside the projection area 460 of the heat dissipation section, the cooling performance of the semiconductor device 300 can be maintained at the same level as when the resin member 454 is not provided.

[0051] As shown in Figure 11(b), in the modified example 1, terminals 315B, 319B, and 320B connected to semiconductor elements 155, 156, 157, and 158 are led out from the side of the semiconductor device 300, and the resin member 454 is arranged in a strip shape in close contact with the heat conductive member 453 on this side. The load sharing by the resin member 454 has the effect of suppressing the outflow of the heat conductive member 453. In particular, by arranging the resin member 454 on the terminal side, the outflow of the heat conductive member 453 to the terminal side can be suppressed. Furthermore, if terminals 315B, 319B, and 320B are on both sides of the side of the semiconductor device 300, the resin member 454 can be formed by drawing two lines, which is excellent in terms of workability.

[0052] As shown in Figure 11(c), in the modified example 2, the resin member 454 is arranged in a strip shape between the projection regions 460 of the heat dissipation parts of the multiple semiconductor elements 155, 156, 157, and 158 built into the semiconductor device 300. Alternatively, the resin member 454 may be arranged between the projection regions 461 of the conductive plates 430, 431, 432, and 433. This has the effect of increasing the load sharing by the resin member 454 while maintaining the cooling performance of the semiconductor device 300, thereby suppressing the outflow of heat from the heat conductive member 453.

[0053] As shown in Figure 11(d), in the modified example 3, the resin members 454 are arranged in a point-like manner outside the projection area 460 of the heat dissipation section, in close contact with the heat conduction member 453. For example, the resin members 454 are arranged outside the projection area 460 of the heat dissipation section, at the four corners and the center of the heat conduction member 453. In this case as well, the load sharing by the resin members 454 has the effect of suppressing the outflow of the heat conduction member 453. Furthermore, since the resin members 454 can be formed in a point-like manner, workability is excellent. The shape and number of resin members 454 arranged in a point-like manner are set appropriately so that the load sharing of the resin members 454 is greater than the load sharing of the heat conduction member 453. Note that although Figures 11(a), 11(b), and 11(c) describe an example in which the resin members 454 are arranged in a strip-like manner, the resin members 454 may also be arranged in a point-like manner.

[0054] In all cases shown in Figures 11(a), 11(b), 11(c), and 11(d), the volume ratio of the resin member 454 to the heat conductive member 453, their respective Young's moduli, the density of the filler, and the cross-linking structure of the resin are set so that the load sharing of the resin member 454 is greater than that of the heat conductive member 453.

[0055] Figures 11(a), 11(b), 11(c), and 11(d) describe the heat dissipation portion of the semiconductor elements 155 and 157 on one side of the semiconductor device 300. Similarly, the resin member 454 and the heat conductive member 453 are arranged on the other side of the semiconductor elements 155 and 157. In this case, the arrangement shape of the resin member 454 on the other side may be the same as the arrangement shape of the resin member 454 on one side shown in Figures 11(a), 11(b), 11(c), and 11(d), that is, it may be the same on both sides, or it may be different on both sides.

[0056] Figures 12(a) and 12(b) are cross-sectional views of the electrical circuit body 400 shown in Figure 1 along the YY line. Figure 12(a) shows an embodiment of the present invention, and Figure 12(b) shows a comparative example.

[0057] As shown in Figures 12(a) and 12(b), the case where there is variation in the thickness of the semiconductor device 300 in the stacking direction of the semiconductor device 300 and the cooling member 340 is illustrated. In these figures, the variation in thickness is depicted as large for clarity and does not represent the actual thickness.

[0058] In this embodiment, the heat conductive member 453 and the resin member 454 are resin cured products that are fluid in their uncured state and lose their fluidity after curing. Therefore, in the adhesion process described with reference to Figure 8(b), the cooling member 340 coated with the uncured heat conductive member 453 and the resin member 454 is brought into close contact with the semiconductor device 300. As shown in Figure 12(a), even if there is variation in the thickness of the semiconductor device 300, this variation can be absorbed and the cooling member 340 can be brought into close contact with the semiconductor device 300. After that, the heat conductive member 453 and the resin member 454 are cured.

[0059] In a comparative example where this embodiment is not applied, a case is shown where a solid spacer 455 is used. In this case, variations in the thickness of the semiconductor device 300 cannot be absorbed, and the cooling member 340 and the semiconductor device 300 do not come into close contact, resulting in a decrease in the reliability of the electrical circuit body 400, such as heat dissipation.

[0060] In this embodiment, since the resin member 454, which has a small compression set, is placed in close contact with the heat conductive member 453, the decrease in heat dissipation due to the outflow of the heat conductive member 453 is suppressed, and a highly reliable electrical circuit body 400 can be provided. Furthermore, since the heat conductive member 453 and the resin member 454 are resin cured products that are fluid in the uncured state and lose their fluidity after curing, they can absorb variations in the thickness of the semiconductor device 300, etc., and a highly reliable electrical circuit body 400 can be provided without a decrease in heat dissipation. In addition, by placing the resin member 454 on the terminal side, the outflow of the heat conductive member 453 to the terminal side is suppressed, and a highly reliable electrical circuit body 400 can be provided.

[0061] Figure 13 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.

[0062] 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.

[0063] As described above, the upper arm circuit includes an active element 155 and an upper arm diode 156 as switching semiconductor elements, and 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 a drive signal output from one or the other of the two driver circuits that constitute the driver circuit 174 and perform switching operations to convert the DC power supplied from the battery 136 into three-phase AC power.

[0064] As described above, 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 6, 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.

[0065] 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.

[0066] The positive terminal 315B and negative terminal 319B 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 points of the upper and lower arm circuits, and the connection points of the upper and lower arm circuits of each upper and lower arm series circuit are connected to the AC terminals 320B of each semiconductor device 300. The AC terminals 320B of each semiconductor device 300 for each phase are connected to the AC output terminals of the power converter 200, and the generated AC power is supplied to the stator windings of the motor generator 192 or 194.

[0067] 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, 182, and 188 are connectors.

[0068] 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.

[0069] Figure 14 is an external perspective view of the power converter 200 shown in Figure 13, and Figure 15 is a cross-sectional perspective view of the power converter 200 shown in Figure 14 along the line XV-XV.

[0070] 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 through which water flows to a cooling member 340, and a cooling water inlet pipe 13 and a cooling water outlet pipe 14, which 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 by 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.

[0071] 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 cooling water inlet pipe 13 and cooling water outlet pipe 14 are routed.

[0072] As shown in Figure 15, an electrical circuit 400 is housed inside the housing 12. A control circuit 172 and a driver circuit 174 are located above the electrical circuit 400, 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 320B 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 315B and the negative terminal 319B, are connected to the positive and negative terminals 362A and 362B of the capacitor module 500, respectively.

[0073] According to the embodiments described above, the following effects and advantages can be obtained. (1) The electrical circuit body 400 includes a semiconductor device 300 that incorporates semiconductor elements 155 and 157 and has heat dissipation portions for the semiconductor elements 155 and 157 formed on at least one side; a cooling member 340 that is positioned opposite the heat dissipation portion of the semiconductor device 300 and cools the heat generated by the semiconductor elements 155 and 157; a heat conductive member 453 positioned between the semiconductor device 300 and the cooling member 340; and a resin member 454 positioned between the semiconductor device 300 and the cooling member 340, outside the projection region 460 of the heat dissipation portion in the stacking direction of the semiconductor device 300 and the cooling member 340, and in close contact with the heat conductive member 453, wherein the resin member 454 has a smaller compression set than the heat conductive member 453. This makes it possible to provide a highly reliable device.

[0074] 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, the above embodiments may be combined with multiple modifications. [Explanation of symbols]

[0075] 10...Upper case, 11...Lower case, 13...Cooling water inlet pipe, 14...Cooling water outlet pipe, 17, 21, 181, 182, 188...Connectors, 18...AC terminals, 43, 140, 142...Inverter circuit section, 155...First semiconductor element (upper arm circuit active element), 156...First semiconductor element (upper arm circuit diode), 157...Second semiconductor element (lower arm circuit active element), 158... • Second semiconductor element (lower arm circuit diode), 172... control circuit, 174... driver circuit, 180... current sensor, 192, 194... motor generator, 200... power converter, 300... semiconductor device, 315B... positive terminal, 319B... negative terminal, 320B... AC terminal, 325E... emitter sense terminal, 325L... lower arm gate terminal, 325C... collector sense Terminal, 325U... Upper arm gate terminal, 340... Cooling material, 341... Pressurization mechanism, 360... Sealing material, 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 collector side), 440... First insulating sheet (emitter side) 441...Second insulating sheet (collector side), 442...First resin insulating layer (emitter side), 443...Second resin insulating layer (collector side), 444...Metal foil, 453...Heat conductive material, 454...Resin material, 455...Spacer, 460...Projection area of ​​heat dissipation section, 461...Projection area of ​​conductor plate, 500...Capacitor module, 601...Transfer molding device, 602...Spring.

Claims

1. A semiconductor device having a semiconductor element built in, with a heat dissipation portion for the semiconductor element formed on at least one side, A cooling member is positioned opposite the heat dissipation portion of the semiconductor device and cools the heat generated by the semiconductor element, A heat conductive member disposed between the aforementioned semiconductor device and the cooling member, The semiconductor device and the cooling member are located between them, and include a resin member that is in close contact with the heat conductive member and arranged linearly or as a point on the outside of the projection area of ​​the heat dissipation portion in the stacking direction of the semiconductor device and the cooling member, The resin member has a smaller compression set than the heat conductive member. The pressure applied to the cooling member against the semiconductor device is shared between the heat conductive member and the resin member, and the load shared by the resin member is greater than that shared by the heat conductive member. Electrical circuit body.

2. In the electrical circuit described in claim 1, The heat conductive member and the resin member are an electrical circuit body which are resin cured products that have fluidity in an uncured state and lose that fluidity after curing.

3. In the electrical circuit described in claim 1, An electrical circuit body in which the Young's modulus of the resin member is higher than that of the heat-conducting member.

4. In the electrical circuit described in claim 1, The semiconductor device comprises a conductive plate that is joined to the semiconductor element, The resin member is an electrical circuit body that is arranged in close contact with the heat conductive member outside the projection area of ​​the conductive plate in the lamination direction.

5. In the electrical circuit body according to any one of claims 1 to 4, A terminal connected to the semiconductor element is derived from at least one side of the semiconductor device. The resin member is an electrical circuit body disposed on the side of the one side from which the terminals are derived.

6. In the electrical circuit body according to claim 5, The resin member is an electrical circuit body arranged on the outer circumference of the heat conductive member.

7. In the electrical circuit body according to claim 6, The semiconductor device incorporates a plurality of the semiconductor elements, The resin member is an electrical circuit body positioned between the projection regions of the heat dissipation portions of the built-in semiconductor elements.

8. In the electrical circuit described in claim 4, The semiconductor device is an electrical circuit body comprising an insulating sheet between the conductive plate, the heat conductive member, and the resin member.

9. In the electrical circuit body according to any one of claims 1 to 4, The heat dissipation portions are formed on both sides of the semiconductor element. The cooling members are arranged on both sides of the semiconductor device facing the heat dissipation portion. The heat conductive member and the resin member are an electrical circuit body arranged on both sides between the semiconductor device and the cooling member.

10. A power conversion device comprising an electrical circuit body according to any one of claims 1 to 4, which converts DC power to AC power.

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