Circuit body and power conversion device

Abstract

This circuit body is provided with: a semiconductor device in which a semiconductor element is incorporated, and in which a heat dissipation part of the semiconductor element is formed on at least one surface; a cooling member that is disposed facing the heat dissipation section of the semiconductor device and cools heat generated by the semiconductor element; a heat conduction member disposed between the semiconductor device and the cooling member; and a resin member which is disposed between the semiconductor device and the cooling member and closely attached to the heat transfer member on the outside of a projection region of the heat dissipation part in a stacking direction of the semiconductor device and the cooling member, and which has a compression permanent strain smaller than that of the heat transfer member.

Description

Technical Field

[0001] The invention relates to a circuit body and a power conversion device. Background Art

[0002] The power conversion device based on the switching action of the semiconductor element has a high conversion efficiency and is therefore widely used in people's livelihood, vehicle-mounted, railway, substation equipment, etc. The semiconductor element generates heat when it is energized. Therefore, a cooling member for cooling the semiconductor element is provided, and a heat conduction member is arranged between the semiconductor device with the semiconductor element built in and the cooling member arranged opposite to the semiconductor device. The heat conduction member conducts the heat from the semiconductor element to the cooling member by being in close contact between the semiconductor device and the cooling member. For the cooling of the semiconductor device, especially in vehicle-mounted applications, high reliability is sought to maintain heat dissipation.

[0003] Patent document 1 discloses a technology in which, in an inverter having a storage portion for a power card having two sides sandwiching semiconductor elements with heat sinks for storing the power card and a circulation path portion for circulating a cooling medium around the power card, an insulating resin is filled in a gap between the power card and the storage portion, and the insulating resin is cured to fix the power card. Prior art literature Patent Literature

[0004] Patent Document 1: Japanese Patent Application Publication No. 2005-237141 Summary of the invention Technical problem to be solved by the invention

[0005] In Patent Document 1, no countermeasures are taken into consideration for the outflow of the heat conducting member, and the reliability of the device is reduced. Technical solutions to technical problems

[0006] The circuit body of the present invention includes: a semiconductor device having a built-in semiconductor element and having a heat dissipation portion of the semiconductor element formed on at least one side; a cooling member arranged opposite to the heat dissipation portion of the semiconductor device and cooling the heat generated by the semiconductor element; a heat conduction member arranged between the semiconductor device and the cooling member; and a resin member, the resin member being arranged between the semiconductor device and the cooling member and in close contact with the heat conduction member on the outside of a projection area of ​​the heat dissipation portion in a stacking direction of the semiconductor device and the cooling member, the compressive permanent strain of the resin member being smaller than that of the heat conduction member. Effects of the Invention

[0007] According to the present invention, it is possible to suppress outflow of the heat conduction member and provide a highly reliable device. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a top view of the circuit body involved in embodiment. Figure 2 It is a cross-sectional view of the circuit body at line XX. Figure 3 It is a cross-sectional stereoscopic view of the circuit body at line YY. Figure 4 It is a cross-sectional stereoscopic view of the circuit body at line XX. Figure 5 It is a semi-transmissive top view of a semiconductor device. Figure 6 It is a circuit diagram of a semiconductor device. Figure 7 (a) Figure 7 (b) Figure 7 (c) Figure 7 (d) is a cross-sectional view illustrating the manufacturing process of the semiconductor device. Figure 8 (a) Figure 8 (b) is a cross-sectional view illustrating the manufacturing process of the circuit body. Fig. 9 (a) Fig. 9 (b) Fig. 9 (c) is a cross-sectional view for explaining plastic deformation of the heat conduction member of the comparative example. Fig.10 (a) Fig.10 (b) Fig.10 (c) is a cross-sectional view illustrating plastic deformation of the heat conduction member according to the embodiment. Fig.11 (a) Fig.11 (b) Fig.11 (c) Fig.11 (d) is a plan view showing the arrangement of the resin members. Fig.12 (a) Fig.12 (b) is a cross-sectional view showing the embodiment and a comparative example of the circuit body. Fig.13 This is a circuit diagram of a power conversion device using a semiconductor device. Fig.14 It is a perspective view of the appearance of the power conversion device. Fig.15 It is a cross-sectional perspective view of a power conversion device. DETAILED DESCRIPTION

[0009] Hereinafter, the embodiments of the present invention will be described with reference to the accompanying drawings. The following description and drawings are examples for illustrating the present invention, and are appropriately omitted and simplified for clarity of the description. The present invention may also be implemented in various other ways. Unless otherwise specified, each structural element may be singular or plural.

[0010] In order to facilitate understanding of the present invention, the positions, sizes, shapes, ranges, etc. of the various structural elements shown in the drawings may not represent actual positions, sizes, shapes, ranges, etc. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, ranges, etc. disclosed in the drawings.

[0011] Figure 1 It is a top view of the circuit body 400 according to the embodiment. The circuit body 400 is composed of the semiconductor device 300 and the cooling member 340 . Figure 1 In the illustrated example, the circuit body 400 is formed by arranging three semiconductor devices 300 in parallel.

[0012] The semiconductor device 300 is sealed by a sealing material 360 and contains semiconductor elements 155 and 157 described later. Heat dissipation parts for dissipating heat caused by the switching operation of the semiconductor elements 155 and 157 are formed on both sides of the semiconductor elements 155 and 157. In addition, in the semiconductor device 300, terminals connected to the semiconductor elements 155 and 157 are also led out from the sealing material 360 on the side of the semiconductor device 300. These terminals are connected to the capacitor module 500 (see Fig.13 ) and the positive terminal 315B and the negative terminal 319B, and the motor generators 192 and 194 connected to the AC circuit (see Fig.13 ) of the AC side terminal 320B and other power terminals through which a large current flows. In addition, the terminals derived from the sealing material 360 on the side of the semiconductor device 300 are the lower arm gate terminal 325L, the collector sense terminal 325C, the emitter sense terminal 325E, the upper arm gate terminal 325U and other terminals. The circuit body 400 in which three semiconductor devices 300 are connected in parallel functions as a power conversion device, which converts direct current and alternating current through the switching action of the semiconductor elements 155 and 157. In addition, the number of semiconductor devices 300 in the circuit body 400 is not limited to three, but can be arbitrarily set according to various forms of the circuit body 400.

[0013] The cooling member 340 is arranged opposite to the heat dissipation part of the semiconductor device 300, and cools the heat generated by the switching action of the semiconductor elements 155 and 156. Specifically, the cooling member 340 forms a flow path for the refrigerant to flow inside, and cools the heat generated by the semiconductor device 300 by the refrigerant flowing in the flow path. The refrigerant can use water, antifreeze obtained by mixing ethylene glycol in water, etc. The cooling member 340 is preferably aluminum with high thermal conductivity and light weight. It is manufactured by extrusion molding, forging, brazing, etc.

[0014] Figure 2 yes Figure 1The cross-sectional view of the circuit body 400 at line XX is shown. Figure 3 yes Figure 1 The circuit body 400 is shown as a cross-sectional perspective view taken along line YY. Figure 4 yes Figure 1 The cross-sectional perspective view taken along line XX of the circuit body 400 shows the semiconductor device 300 after the cooling member 340 and the heat conduction member 453 are removed from the circuit body 400 .

[0015] like Figure 2 As shown, the circuit body 400 includes a pressurizing mechanism 341 that pressurizes the cooling members 340 provided on both sides of the semiconductor device 300 from both sides. The pressurizing mechanism 341 is not shown in the figure, but is a mechanism that connects the cooling members 340 on both sides with screws, etc., and pressurizes the semiconductor device 300 side.

[0016] like Figure 2 As shown, the first semiconductor element forming the upper arm circuit of the power conversion device includes an active element 155, a diode 156 (see the following Figure 5 , Figure 6 ). In addition, Si, SiC, GaN, GaO, C, etc. can be used as active elements. When the body diode of the active element 155 is used, the additional diode can be omitted. The collector side of the first semiconductor element 155 is bonded to the second conductor plate 431. Solder or sintered metal can be used for this bonding. The first conductor plate 430 is bonded to the emitter side of the first semiconductor element 155.

[0017] like Figure 3 As shown, as the second semiconductor element forming the lower arm circuit, it includes an active element 157, a diode 158 (refer to the following Figure 5 , Figure 6 ).like Figure 3 As shown, the collector side of the second semiconductor element 157 is bonded to the fourth conductor plate 433. The third conductor plate 432 is bonded to the emitter side of the second semiconductor element 157.

[0018] The conductor plates 430, 431, 432, 433 are not particularly limited as long as they are made of materials with high electrical conductivity and thermal conductivity, but preferably use metal materials such as copper or aluminum materials, composite materials of metal materials and high thermal conductivity diamond, carbon, ceramics, etc. These can be used alone or plated with Ni, Ag, etc. to improve bonding with solder or sintered metal.

[0019] like Figure 2 , Figure 3 , Figure 4As shown, the conductor plates 430, 431, 432, 433, in addition to the function of conducting current, also function as a heat conducting member that conducts heat generated by the semiconductor elements 155, 156, 157, 158 to the cooling member 340. The conductor plates 430, 431, 432, 433 and the cooling member 340 have different potentials, and therefore, it is preferable to use insulating sheets 440, 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 adhesion to the heat sink, but it is preferably an epoxy resin insulating layer in which a powdered inorganic filler is dispersed. This is because the balance between adhesion and heat dissipation is better. The insulating sheets 440 and 441 can be the resin insulating layer 443 alone, but it is preferable to set the metal foil 444 on the side that contacts the heat conduction member 453 described later. The insulating sheets 440 and 441 are cured simultaneously with the sealing material 360 in the transfer molding process. In the transfer molding process, when the insulating sheets 440 and 441 are mounted on the mold, in order to prevent adhesion to the mold, a release sheet or metal foil 444 is set on the contact surface between the insulating sheets 440 and 441 and the mold. Due to poor thermal conductivity, the release sheet needs to be peeled off in the process after transfer molding, but when the metal foil 444 is used, by selecting a metal with high thermal conductivity such as copper or aluminum, it can be used without peeling off after transfer molding.

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

[0022] like Figure 2 As shown, in order to reduce the contact thermal resistance between the semiconductor device 300 and the cooling member 340, a heat conduction member 453 is arranged between the semiconductor device 300 and the cooling member 340. In addition, between the semiconductor device 300 and the cooling member 340, outside the projection area 460 of the heat dissipation portion in the stacking direction of the semiconductor device 300 and the cooling member 340, a resin member 454 is arranged in close contact with the heat conduction member 453.

[0023] In order to ensure workability and long-term reliability, the heat conduction component 453 is a cured resin material that has fluidity in the uncured state and no fluidity after curing. Curable resin materials have the advantages of low viscosity during coating, excellent workability, and the ability to improve mechanical properties through curing. Curing can be achieved by thermal curing, moisture curing, ultraviolet curing, etc., but thermal curing is preferred for deep curing. In order to make the semiconductor device 300 and the cooling component 340 with different thermal expansion coefficients fit closely together, the heat conduction component 453 needs to reduce stress. Therefore, the Young's modulus of the heat conduction component 453 is preferably 50 MPa or less. The Young's modulus in this embodiment is a value measured at a frequency of 10 Hz, a strain of 0.1%, and a temperature of 25°C in a dynamic viscoelasticity test in the tensile or compressive direction.

[0024] The heat conduction member 453 is a material obtained by mixing a filler material in a resin. The most preferred resin is a silicone resin whose elastic modulus changes little from about -40°C to about 200°C. The filler material is a high heat conduction material such as metal, ceramic, or carbon-based material. Since the heat conduction member 453 is filled with a filler material in the resin, the elastic modulus becomes low, and thus the heat conduction member 453 becomes a cured product that is easy to plastically deform with a large compression permanent strain. The compression permanent strain in this embodiment is the strain remaining 30 minutes after a 10% compression displacement is applied at room temperature for 30 minutes and the load is released.

[0025] For the sake of workability and heat dissipation, the resin member 454 is a cured resin that has fluidity in an uncured state and no fluidity after curing. The cured resin has low viscosity during application and excellent workability. In addition, it can be thinned to the same thickness as the heat conduction member 453 by pressurization and can function as a spacer between the semiconductor device 300 and the cooling member 340 by curing. Therefore, compared with the case of configuring a spacer of a certain thickness, the heat conduction member 453 can be thinned and the heat dissipation can be improved. Regarding this point, please refer to Fig.12 This will be described later.

[0026] The Young's modulus of the resin member 454 is preferably higher than that of the heat conduction member 453. The resin member 454 is arranged outside the projection region 460 in close contact with the heat conduction member 453, but has a higher stress than that of the heat conduction member 453 between the semiconductor device 300 and the cooling member 340, thereby suppressing 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 may be a material in which a filler material is mixed into the resin. In any case, the resin member 454 is a solidified material having a smaller compressive permanent strain than the heat conduction member 453. Since the compressive permanent strain of the resin member 454 is smaller than that of the heat conduction member 453, it is possible to share the pressure of pressing the cooling member 340 against the semiconductor device 300 by the pressurizing mechanism 341, thereby suppressing the heat conduction member 453 from plastically deforming and flowing out of the semiconductor device 300. That is, the resin member 454 is set to share a greater load than the heat conduction member 453. Regarding this point, reference will be made to Fig.10 This will be described later.

[0028] The resin member 454 is arranged in Figure 4 As shown, the resin member 454 is disposed outside the projection area 460 of the heat dissipation portion in the stacking direction of at least the semiconductor device 300 and the cooling member 340. As a result, the heat of the semiconductor elements 155 to 158 can be conducted to the heat conduction member 453 without being hindered by the resin member 454. Alternatively, the resin member 454 may be disposed outside the projection area 461 of the conductor plates 430, 431, 432, 433 in the stacking direction of the semiconductor device 300 and the cooling member 340. As a result, the heat conducted from the semiconductor elements 155 and 156 via the conductor plates 430, 431, 432, 433 can be conducted to the heat conduction member 453 without being hindered by the resin member 454. In any case, the resin member 454 is a material obtained by mixing a filler material as a high heat conduction material in a resin, and thus, although the heat conduction is less than that of the heat conduction member 453, it is possible to prevent the heat conduction from being seriously hindered. Furthermore, in any case, the filler and the like are blended so that the Young's modulus of the resin member 454 is higher than the Young's modulus of the heat conduction member 453 .

[0029] Figure 5 FIG. 3 is a semi-transmissive top view of the semiconductor device 300 . Figure 6 is a circuit diagram of the semiconductor device 300 . like Figure 5 , Figure 6 As shown, the positive side terminal 315B is output from the collector side of the upper arm circuit and connected to the positive side of the battery or capacitor. The upper arm gate terminal 325U is output from the gate of the active element 155 of the upper arm circuit. The negative side terminal 319B is output from the emitter of the lower arm circuit in advance and connected to the negative side of the battery or capacitor, or GND. The lower arm gate terminal 325L is output from the gate of the active element 157 of the lower arm circuit. The AC side terminal 320B is output from the collector side of the lower arm circuit and connected to the motor. In the case of neutral point grounding, the lower arm circuit is connected to the negative side of the capacitor instead of 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] In addition, the conductor plate (emitter side of the upper arm circuit) 430 and the conductor plate (collector side of the upper arm circuit) 431 are arranged above and below the active element 155 and the diode 156 of the semiconductor element (upper arm circuit). The conductor plate (emitter side of the lower arm circuit) 432 and the conductor plate (collector side of the lower arm circuit) 433 are arranged above and below the active element 157 and the diode 158 of the semiconductor element (lower arm circuit).

[0032] The semiconductor device 300 of this embodiment has a structure in which two arm circuits of an upper arm circuit and a lower arm circuit are integrated into one module, that is, a 2-in-1 structure. In addition, a structure in which a plurality of upper arm circuits and lower arm circuits are integrated into one module can also be used. In this case, the number of output terminals from the semiconductor device 300 can be reduced and miniaturization can be achieved.

[0033] Figure 7 (a) Figure 7 (b) Figure 7 (c) Figure 7 (d) is a cross-sectional view for explaining the manufacturing process of the semiconductor device 300. Figure 2 Similarly, it is represented by a cross-sectional view taken along line XX corresponding to one module.

[0034] Figure 7 (a) is a temporary mounting process. The collector side of the semiconductor element 155 and the cathode side of the semiconductor element 156 are connected to the second conductor plate 431, and the gate electrode, emitter sense electrode, and collector electrode of the 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. In addition, the emitter side of the semiconductor element 155 and the anode side of the semiconductor element 156 are connected to the first conductor plate 430 to manufacture the circuit body 310 on the upper arm side. Similarly, the collector side of the semiconductor element 157 and the cathode side of the semiconductor element 158 ​​are connected to the fourth conductor plate 433, and the gate electrode, emitter sense electrode, and collector electrode of the 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 the semiconductor element 157 and the anode side of the semiconductor element 158 ​​are connected to the third conductor plate 432 to manufacture the circuit body 310 on the lower arm side. Figure 7 (a) Only the circuit body 310 on the upper arm side is shown, and the circuit body 310 on the lower arm side is not shown. Then, the insulating sheets 440 and 441 are temporarily installed on the conductor plates 430 to 433. The so-called temporary installation means that in the subsequent transfer molding process, the insulating sheets 440 and 441 are temporarily attached using the adhesion force of the insulating sheets 440 and 441 under the condition that the insulating sheets 440 and 441 are cured and there is room for adhesion.

[0036] Figure 7 (b)~ Figure 7 (d) is a transfer molding process. The transfer molding device 601 sets a spring 602 in a mold 603. Through the spring 602, even if the height of the circuit body 310 deviates, excessive pressure will not be applied to the semiconductor elements 155 to 158, and a specified load can be applied by the force of the spring 602. In addition, the transfer molding device 601 has a vacuum degassing mechanism not shown in the figure. Through vacuum degassing, even if the sealing material 360 composed of resin or the like is drawn into the gap, the gap can be compressed to be smaller, thereby improving the insulation. In addition, by covering the circuit body 310 with a release film not shown in the figure, it is possible to protect the spring drive part from the invasion of resin burrs.

[0037] like Figure 7 As shown in (b), the circuit body 310 to which the insulating sheets 440 and 441 are temporarily attached is set in the mold 603 which is preheated to a constant temperature of 175°C. Figure 7 As shown in (c), the upper and lower molds 603 are clamped. At this time, the insulating sheets 440, 441 and the conductor plates 430 to 433 are pressed and closely attached by the spring 602. When the terminal portions of the outer peripheries of the conductor plates 431, 433 are clamped by the mold, the conductor plates 431, 433 on the collector side are pressed toward the lower mold 603, and added to the force of the spring 602, they are pressed and attached to the insulating sheet 441 with a stronger force than the conductor plates 430, 432 on the emitter side.

[0038] Afterwards, if Figure 7 As shown in (d), the sealing material 360 is injected into the mold 603. Thereafter, the semiconductor device 300 sealed with resin is taken out from the transfer molding device 601 and post-cured at 175°C for more than 2 hours.

[0039] Figure 8 (a) Figure 8 (b) is a cross-sectional view illustrating a manufacturing process of the circuit body 400. This process uses Figure 7 The semiconductor device 300 manufactured by the step (d) is performed. Figure 8 (a) is a coating step. The heat conducting member 453 and the resin member 454 are coated on the cooling member 340. For details about the coating location, etc., refer to Fig.11 To be described later.

[0040] Figure 8 (b) is a bonding / curing step in which the cooling member 340 coated with the heat conduction member 453 and the resin member 454 is bonded to the semiconductor device 300. Then, the heat conduction member 453 and the resin member 454 are cured to produce the circuit body 400.

[0041] Fig. 9 (a) Fig. 9 (b) Fig. 9 (c) is a cross-sectional view for explaining plastic deformation of the heat conduction member 453 of the comparative example. This comparative example is a case where the present embodiment is not applied.

[0042] like Fig. 9 As shown in (a), the heat conduction member 453 is pressed by the pressurizing mechanism 341 and comes into close contact with the semiconductor device 300 .

[0043] like Fig. 9 As shown in (b), when the semiconductor elements 155 and 156 generate heat due to power supply, the temperature of the conductor plate 430 joined to the semiconductor elements 155 and 156 rises, and the conductor plate 430 partially expands toward the cooling member 340 in the direction of arrow A with the projection area 460 of the heat dissipation portion as the center. As a result, the heat conduction member 453 is partially compressed and plastically deformed, and is pushed outward B of the projection area 460.

[0044] like Fig. 9 As shown in (c), when the conduction of electricity to the semiconductor elements 155 and 156 is stopped and the conductor plate 430 is cooled, the local thermal expansion of the conductor plate 430 returns to its original state. The portion of the heat conduction member 453 that is plastically deformed has a reduced compressive stress due to the plastic deformation, and therefore cannot share the pressure C of the pressurizing mechanism 341. Therefore, the pressure C of the pressurizing mechanism 341 increases the pressure on the heat conduction member 453 outside the projection area 460 that is not plastically deformed. As a result, the heat conduction member 453 outside the projection area 460 is plastically deformed, and the heat conduction member 453 flows out to the outside D of the semiconductor device 300, and the thickness of the heat conduction member 453 is reduced. In addition, due to the repetition of this outflow, the density of the filling material filled in the heat conduction member 453 becomes sparse, and the heat dissipation of the heat conduction member 453 is reduced. In addition, if the outflowing heat conduction member 453 contacts the terminal or the like led out from the semiconductor device 300, there is a concern that the insulation is reduced.

[0045] Fig.10 (a) Fig.10 (b) Fig.10(c) is a cross-sectional view for explaining plastic deformation of the heat conduction member 453 according to the present embodiment.

[0046] like Fig.10 As shown in (a), the heat conduction member 453 and the resin member 454 are pressed by the pressurizing mechanism 341 and come into close contact with the semiconductor device 300 .

[0047] like Fig.10 As shown in (b), when the semiconductor elements 155 and 156 generate heat due to power supply, the temperature of the conductor plate 430 bonded to the semiconductor elements 155 and 156 rises, and the conductor plate 430 is locally thermally expanded in the direction of arrow A toward the cooling member 340 with the projection area 460 of the heat dissipation portion as the center. As a result, the heat conduction member 453 is locally compressed and plastically deformed, and tries to move to the outside B of the projection area 460. However, since the resin member 454 having a smaller permanent compression strain than the heat conduction member 453 is disposed between the semiconductor device 300 and the cooling member 340 and outside the projection area 460 of the heat dissipation portion, the force of the heat conduction member 453 to move to the outside B is pushed back in the direction of arrow E by the repulsive force of the resin member 454, thereby suppressing the movement.

[0048] like Fig.10 As shown in (c), when the power supply to the semiconductor elements 155 and 156 is stopped and the conductor plate 430 is cooled, the local thermal expansion of the conductor plate 430 returns to its original state. The portion of the heat conduction member 453 that is plastically deformed does not share the pressure of the pressure mechanism 341 due to the plastic deformation, so the pressure applied to the heat conduction member 453 outside B of the projection area 460 increases. However, since the permanent compression strain of the resin member 454 is smaller than that of the heat conduction member 453, the resin member 454 shares the pressure as shown by the arrow F. In other words, the resin member 454 is set to share a greater load than the heat conduction member 453, so it shares the pressure. As a result, it is possible to suppress the reduction in the thickness of the heat conduction member 453. The thickness of the heat conduction member 453 does not change, so it is possible to prevent the heat conduction member 453 from moving or flowing out on a large scale. As a result, it is possible to suppress the reduction in heat dissipation. Furthermore, by arranging the resin member 454 on the terminal side of the semiconductor device 300 , it is possible to suppress and prevent the heat conduction member 453 from flowing out to the outside of the semiconductor device 300 and reaching the terminal and the like.

[0049] Fig.11 (a) Fig.11 (b) Fig.11 (c) Fig.11 (d) is a top view showing the arrangement of the resin member 454. Figure 5 The semi-transmissive top view of the semiconductor device 300 shown in FIG. 1 shows the arrangement position of the resin member 454. Fig.11 (a) represents an embodiment, Fig.11(b) shows modification example 1, Fig.11 (c) represents modification example 2, Fig.11 (d) shows Modification 3. In these figures, the heat conduction member 453 is shown in a transparent state.

[0050] like Fig.11 As shown in (a), in this embodiment, the resin member 454 surrounds the outer periphery of the heat conduction member 453 and is arranged in a belt shape in close contact with the heat conduction member 453. The resin member 454 is arranged outside the projection area 461 of the conductor plates 430, 431, 432, and 433. In addition, the resin member 454 only needs to be arranged outside the projection area 460 of the heat dissipation portion. The load sharing of the resin member 454 has an effect of suppressing the outflow of the heat conduction member 453. In addition, there is an effect of preventing the outflow due to the resin member 454 surrounding the heat conduction member 453. Generally, the thermal conductivity of the resin member 454 is lower than that of the heat conduction member 453, but by arranging it outside the projection area 460 of the heat dissipation portion, it is possible to suppress the reduction in the cooling performance of the semiconductor device 300. In addition, by arranging the resin member 454 outside the projection area 460 of the heat dissipation portion, the cooling performance of the semiconductor device 300 can be maintained to the same level as when the resin member 454 is not provided.

[0051] like Fig.11 As shown in (b), in the first modification, the terminals 315B, 319B, 320B connected to the semiconductor elements 155, 156, 157, 158 are led out from the side surface of the semiconductor device 300, but the resin member 454 is arranged in a strip shape in close contact with the heat conduction member 453 on the side surface. The load sharing of the resin member 454 has an effect of suppressing the outflow of the heat conduction member 453. In particular, by arranging the resin member 454 on the terminal side, it is possible to suppress the outflow of the heat conduction member 453 to the terminal side. In addition, when the terminals 315B, 319B, 320B are located on both sides of the side surface of the semiconductor device 300, the resin member 454 can be formed in a manner of pulling two lines, so that the workability is excellent.

[0052] like Fig.11 As shown in (c), in the second modification, the resin member 454 is arranged in a strip shape between the projection areas 460 of the heat dissipation parts of the plurality of semiconductor elements 155, 156, 157, 158 built into the semiconductor device 300. In addition, the resin member 454 is arranged between the projection areas 461 of the conductor plates 430, 431, 432, 433. While maintaining the cooling performance of the semiconductor device 300, there is an effect of increasing the load sharing of the resin member 454 and suppressing the outflow of the heat conduction member 453.

[0053] like Fig.11As shown in (d), in variant example 3, the resin member 454 is arranged in a dot shape on the outside of the projection area 460 of the heat dissipation portion and is closely attached to the heat conduction member 453. As an example, the resin member 454 is arranged at the four corners and the center of the heat conduction member 453 on the outside of the projection area 460 of the heat dissipation portion. In this case, the load sharing of the resin member 454 also has the effect of suppressing the outflow of the heat conduction member 453. In addition, since the resin member 454 can be formed in a dot shape, the operability is excellent. The shape or number of the resin members 454 arranged in a dot shape is appropriately set so that the load sharing of the resin member 454 is greater than the load sharing of the heat conduction member 453. In addition, in Fig.11 (a) Fig.11 (b) Fig.11 In (c), an example in which the resin member 454 is arranged in a strip shape is described, but the resin members 454 may be arranged in a dot shape.

[0054] exist Fig.11 (a) Fig.11 (b) Fig.11 (c) Fig.11 In any of the cases shown in (d), the volume ratio of the resin member 454 and the heat conduction member 453, their respective Young's moduli, the density of the filler material, the cross-linked structure of the resin, etc. are set so that the load sharing of the resin member 454 is greater than the load sharing of the heat conduction member 453.

[0055] exist Fig.11 (a) Fig.11 (b) Fig.11 (c) Fig.11 In (d), the heat dissipation portion of the semiconductor elements 155 and 157 on one side of the semiconductor device 300 is described, but the resin member 454 and the heat conduction member 453 are similarly 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 can be the same as that of Fig.11 (a) Fig.11 (b) Fig.11 (c) Fig.11 The arrangement shape of the resin member 454 on one side shown in (d) may be the same, that is, the same on both sides or different on both sides.

[0056] Fig.12 (a), 12(b) are Figure 1 A cross-sectional view of the circuit body 400 taken along line YY is shown. Fig.12 (a) shows an embodiment of the present invention, Fig.12 (b) shows a comparative example.

[0057] like Fig.12 (a) Fig.12(b) shows a case where there is a variation in thickness of the semiconductor device 300 in the stacking direction of the semiconductor device 300 and the cooling member 340. In these figures, the variation in thickness is depicted to be large for easy understanding, and the actual thickness is not shown.

[0058] In this embodiment, the heat conducting member 453 and the resin member 454 are resin cured materials that have fluidity in an uncured state and lose fluidity after curing. Figure 8 In the bonding step described in (b), the cooling member 340 coated with the uncured heat conducting member 453 and the resin member 454 is bonded to the semiconductor device 300. Fig.12 As shown in (a), even if there is a variation in the thickness of the semiconductor device 300, the variation can be absorbed and the cooling member 340 can be brought into close contact with the semiconductor device 300. Thereafter, the heat conduction member 453 and the resin member 454 are cured.

[0059] A comparative example not applying this embodiment shows a case of using a solid spacer 455. In this case, since variations in the thickness of the semiconductor device 300 cannot be absorbed, the cooling member 340 and the semiconductor device 300 are not in close contact, and the reliability of the circuit body 400 such as heat dissipation is reduced.

[0060] In this embodiment, since the resin member 454 having a small compression permanent strain is arranged in close contact with the heat conduction member 453, it is possible to suppress the reduction in heat dissipation due to the outflow of the heat conduction member 453, and provide a circuit body 400 with high reliability. In addition, the heat conduction member 453 and the resin member 454 are resin cured materials that have fluidity in an uncured state and lose fluidity after curing, and thus it is possible to absorb the thickness variation of the semiconductor device 300, and provide a circuit body 400 with high reliability without reducing heat dissipation. In addition, by arranging the resin member 454 on the terminal side, it is possible to suppress the outflow of the heat conduction member 453 to the terminal side, and provide a circuit body 400 with high reliability.

[0061] Fig.13 2 is a circuit diagram of a power conversion device 200 using a semiconductor device 300 . The power conversion device 200 includes inverter circuit units 140 and 142, an inverter circuit unit 43 for auxiliary machines, and a capacitor module 500. The inverter circuit units 140 and 142 have a plurality of semiconductor devices 300, and a three-phase bridge circuit is formed by connecting them. In the case of a large current capacity, the semiconductor devices 300 are further connected in parallel, and these parallel connections are performed corresponding to each phase of the three-phase inverter circuit, so that the increase in current capacity can be coped with. In addition, by connecting the active elements 155 and 157, diodes 156 and 158 as semiconductor elements built into the semiconductor device 300 in parallel, it is also possible to cope with the increase in current capacity.

[0062] The inverter circuit unit 140 and the inverter circuit unit 142 have the same basic circuit configuration, and their control methods and operations are also basically the same. The outline of the circuit operation of the inverter circuit unit 140 and the like is well known, so a detailed description thereof will be omitted here.

[0063] As described above, the upper arm circuit includes the upper arm active element 155 and the upper arm diode 156 as semiconductor elements for switching, and the lower arm circuit includes the lower arm active element 157 and the lower arm diode 158 as semiconductor elements for switching. The active elements 155 and 157 receive a drive signal output from one or the other of the two drive circuits constituting the drive circuit 174 to perform a switching operation, and convert the DC power supplied from the battery 136 into a three-phase AC power.

[0064] As described above, the upper arm active element 155 and the lower arm active element 157 include a collector electrode, an emitter electrode, and a gate electrode. The upper arm diode 156 and the lower arm diode 158 include two electrodes, a cathode electrode and an anode electrode. Figure 6 As shown, the cathode electrodes of the diodes 156 and 158 are electrically connected to the collector electrodes of the active elements 155 and 157, respectively, and the anode electrodes of the diodes 156 and 158 are electrically connected to the emitter electrodes of the active elements 155 and 157, respectively. As a result, the current flows from the emitter electrodes of the active elements 155 for the upper arm and the active elements 157 for the lower arm toward the collector electrodes in a clockwise 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 an active element. In this case, the upper arm diode 156 and the lower arm diode 158 are unnecessary.

[0066] The positive terminal 315B and the negative terminal 319B of each upper and lower arm series circuit are respectively connected to the DC terminal for capacitor connection of the capacitor module 500. The connection parts of the upper arm circuit and the lower arm circuit respectively generate AC power, and the connection parts of the upper arm circuit and the lower arm circuit of each upper and lower arm series circuit are connected to the AC side terminal 320B of each semiconductor device 300. The AC side terminal 320B of each semiconductor device 300 of each phase is respectively connected to the AC output terminal of the power conversion device 200, and the generated AC power is supplied to the stator winding of the motor generator 192 or 194.

[0067] The control circuit 172 generates a timing signal for controlling 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 a control device or a sensor (e.g., a current sensor 180) on the vehicle side. The drive circuit 174 generates a drive signal for switching the active element 155 for the upper arm and the active element 157 for the lower arm based on the timing signal output from the control circuit 172. In addition, 181, 182, and 188 are connectors.

[0068] The upper and lower arm series circuits include a temperature sensor (not shown), and the temperature information of the upper and lower arm series circuits is input to the microcomputer. In addition, the voltage information of the DC positive side of the upper and lower arm series circuits is input to the microcomputer. Based on this information, the microcomputer performs over-temperature detection and over-voltage detection. When over-temperature or over-voltage is detected, the microcomputer stops the switching action of all the active elements 155 for the upper arm and the active elements 157 for the lower arm to protect the upper and lower arm series circuits from over-temperature or over-voltage.

[0069] Fig.14 yes Fig.13 The external perspective view of the power conversion device 200 is shown in FIG. Fig.15 yes Fig.14 The power conversion device 200 is a cross-sectional perspective view taken along line XV-XV shown in FIG.

[0070] The power conversion device 200 has a frame 12 formed of a lower shell 11 and an upper shell 10 and formed in a roughly rectangular shape. The circuit body 400, the capacitor module 500, etc. are housed inside the frame 12. The circuit body 400 has a cooling flow path flowing to the cooling member 340, and a cooling water inlet pipe 13 and a cooling water outlet pipe 14 connected to the cooling flow path protrude from one side of the frame 12. The upper side of the lower shell 11 is open, and the upper shell 10 is installed on the lower shell 11 by blocking the opening of the lower shell 11. The upper shell 10 and the lower shell 11 are formed of aluminum alloy, etc., and are sealed and fixed relative to the outside. The upper shell 10 and the lower shell 11 can be integrally formed. By setting the frame 12 to a simple rectangular shape, it is easy to install on a vehicle, etc., and it is also easy to produce.

[0071] The connector 17 is mounted on one side surface in the longitudinal direction of the housing 12, and the AC terminal 18 is connected to the connector 17. In addition, a connector 21 is provided on the surface from which the cooling water inflow pipe 13 and the cooling water outflow pipe 14 are led out.

[0072] like Fig.15 As shown, the circuit body 400 is housed in the frame 12. The control circuit 172 and the drive circuit 174 are arranged above the circuit body 400, and the capacitor module 500 is housed on the DC terminal side of the circuit body 400. By arranging the capacitor module at the same height as the circuit body 400, the power conversion device 200 can be made thinner, and the degree of freedom of installation in the vehicle can be improved. The AC side terminal 320B of the circuit body 400 passes through the current sensor 180 and is connected to the connector 188. In addition, the positive side terminal 315B and the negative side terminal 319B as the DC terminal of the semiconductor device 300 are respectively connected to the positive / negative terminals 362A and 362B of the capacitor module 500.

[0073] According to the above-described embodiment, the following effects can be obtained. (1) The circuit body 400 includes: a semiconductor device 300 having semiconductor elements 155 and 157 built therein and having a heat dissipation portion for the semiconductor elements 155 and 157 formed on at least one surface; a cooling member 340 disposed opposite to the heat dissipation portion of the semiconductor device 300 and cooling heat generated by the semiconductor elements 155 and 157; a heat conduction member 453 disposed between the semiconductor device 300 and the cooling member 340; and a resin member 454 disposed between the semiconductor device 300 and the cooling member 340 and in close contact with the heat conduction member 453 on the outside of a projection area 460 of the heat dissipation portion in the stacking direction of the semiconductor device 300 and the cooling member 340, wherein the compressive permanent strain of the resin member 454 is smaller than that of the heat conduction member 453. Thus, a highly reliable device can be provided.

[0074] The present invention is not limited to the above-mentioned embodiments, and other modes that can be considered within the technical concept of the present invention are also included in the scope of the present invention as long as the characteristics of the present invention are not impaired. In addition, a structure combining the above-mentioned embodiments and a plurality of modified examples is also possible. Description of symbols

[0075] 10 upper case, 11 lower case, 13 cooling water inlet pipe, 14 cooling water outlet pipe, 17, 21, 181, 182, 188 connector, 18 AC terminal, 43, 140, 142 inverter circuit unit, 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 drive circuit, 180 current sensor, 192, 194 electric generator, 200 power conversion device, 300 semiconductor device, 315B positive electrode side terminal, 319B negative electrode side terminal, 320B AC side terminal, 325E emitter sense terminal, 325L lower arm gate terminal, 325C collector 325U upper arm gate terminal, 340 cooling member, 341 pressurizing mechanism, 360 sealing material, 400 circuit body, 420 conductor plate, 430 first conductor plate (emitter side of upper arm circuit), 431 second conductor plate (collector side of upper arm circuit), 432 third conductor plate (emitter side of lower arm circuit), 433 fourth conductor plate (collector side of lower arm circuit), 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 conduction member, 454 resin member, 455 spacer, 460 projection area of ​​heat dissipation portion, 461 projection area of ​​conductor plate, 500 capacitor module, 601 transfer molding device, 602 spring.

Claims

1. A circuit body, characterized in that: include: A semiconductor device having a built-in semiconductor element and having 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 cooling heat generated by the semiconductor element; a heat conduction member disposed between the semiconductor device and the cooling member; as well as a resin member disposed between the semiconductor device and the cooling member and in close contact with the heat conducting member outside a projection area of ​​the heat dissipation portion in a stacking direction of the semiconductor device and the cooling member, The resin member has a smaller compressive permanent strain than the heat conductive member.

2. The circuit body according to claim 1, characterized in that: The heat conduction member and the resin member are resin cured products that have fluidity in an uncured state and lose the fluidity after curing.

3. The circuit body according to claim 1, characterized in that: The resin member has a Young's modulus higher than that of the heat conduction member.

4. The circuit body according to claim 1, characterized in that: The semiconductor device includes a conductive plate bonded to the semiconductor element. The resin member is arranged in close contact with the heat conductive member outside a projection area of ​​the conductor plate in the stacking direction.

5. The circuit body according to any one of claims 1 to 4, characterized in that: A terminal connected to the semiconductor element is led out from at least one side surface of the semiconductor device. The resin member is arranged on a side of the one side surface from which the terminal is led out.

6. The circuit body according to claim 5, characterized in that: The resin member is disposed on the outer periphery of the heat conduction member.

7. The circuit body according to claim 6, characterized in that: The semiconductor device has a plurality of semiconductor elements built therein. The resin member is arranged between projection areas of the heat dissipating portions of the built-in semiconductor elements.

8. The circuit body according to any one of claims 1 to 4, characterized in that: The resin member is configured in a belt shape.

9. The circuit body according to any one of claims 1 to 4, characterized in that: The resin members are arranged in a dot pattern.

10. The circuit body according to claim 4, characterized in that: The semiconductor device includes an insulating sheet between the conductor plate, the heat conduction member, and the resin member.

11. The circuit body according to any one of claims 1 to 4, characterized in that: The heat dissipation portion is formed on both sides of the semiconductor element, The cooling member is arranged on both sides facing the heat dissipation portion of the semiconductor device. The heat conduction member and the resin member are disposed on both surfaces between the semiconductor device and the cooling member.

12. A power conversion device, characterized in that: The circuit comprises the circuit body as claimed in any one of claims 1 to 4, and converts direct current into alternating current.

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