Circuit body, power conversion device, and method for manufacturing circuit body

Abstract

The present application includes: a power semiconductor element; a first conductor plate connected to one face of the power semiconductor element; a first sheet member having a first resin insulating layer and covering at least a surface of the first conductor plate; a sealing material sealing the power semiconductor element, the first conductor plate, and an end portion of the first sheet member; and a first cooling member in close contact with the first sheet member, the first sheet member having: a buried portion in which the end portion of the first sheet member is covered with the sealing material; a heat dissipation surface portion as a region overlapping the surface of the first conductor plate; and a margin portion as a region between the buried portion and the heat dissipation surface portion, the margin portion being recessed inwardly more than the heat dissipation surface portion, and the buried portion being recessed inwardly more than the margin portion.

Description

Technical Field

[0001] This invention relates to circuit elements, power conversion devices, and methods for manufacturing circuit elements. Background Technology

[0002] Power conversion devices using power semiconductor components are widely used in civilian, automotive, railway, and power transmission equipment applications due to their high conversion efficiency. These power semiconductor components generate heat when energized, thus requiring excellent heat dissipation. For example, in automotive applications, water-cooled, high-efficiency devices are employed for miniaturization and weight reduction.

[0003] Patent document 1 discloses a circuit structure in which a molding resin for sealing semiconductor elements and a heat sink has a recess in the position surrounding the heat sink surface, an insulating sheet covers the entire heat sink surface, and the end is bonded to the recess.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2013-258334 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] In the case where a cooling component is closely attached to the heat dissipation surface of the device described in Patent Document 1, if the circuit body warps, the tightness between it and the cooling component weakens, and the heat dissipation is impaired.

[0009] Technical means to solve the problem

[0010] The circuit of the present invention comprises: a power semiconductor element; a first conductor plate connected to one side of the power semiconductor element; a first sheet member having a first resin insulating layer and at least covering the surface of the first conductor plate; a sealing material sealing the power semiconductor element, the first conductor plate, and the ends of the first sheet member; and a first cooling member in close contact with the first sheet member, the first sheet member having: a buried portion where the ends of the first sheet member are covered by the sealing material; a heat dissipation surface portion overlapping the surface of the first conductor plate; and a blank portion forming the area between the buried portion and the heat dissipation surface portion, the blank portion being recessed inwardly than the heat dissipation surface portion, and the buried portion being recessed inwardly than the blank portion.

[0011] The method for manufacturing the circuit body of the present invention comprises the following steps: a first step is to seal a power semiconductor element, a first conductor plate connected to one side of the power semiconductor element, and a first sheet member having a first resin insulating layer and at least covering the surface of the first conductor plate with a sealing material, wherein the first sheet member has: an embedded portion at the end of the first sheet member covered by the sealing material; a heat dissipation surface portion as a region overlapping the surface of the first conductor plate; and a blank portion as a region between the embedded portion and the heat dissipation surface portion, wherein the embedded portion is recessed inward compared to the heat dissipation surface portion and the blank portion, and sealed with the sealing material; a second step is to cure and shrink the sealing material, thereby causing the blank portion to be recessed inward compared to the heat dissipation surface portion; and a third step is to make a cooling member in close contact with the first sheet member.

[0012] The effects of the invention

[0013] According to the present invention, even if the circuit body warps, the tightness between it and the cooling component can be ensured without compromising heat dissipation. Attached Figure Description

[0014] Figure 1 It is a plan view of the circuit body.

[0015] Figure 2 It is a circuit body Figure 1 The cross-sectional view of line XX shown.

[0016] Figure 3 It is a circuit body Figure 1 The cross-sectional view of the YY line is shown.

[0017] Figure 4 yes Figure 1 The diagram shows a cross-sectional perspective view of the power module of the XX line.

[0018] Figure 5 (a) to (c) are cross-sectional views showing the manufacturing method of the circuit body.

[0019] Figure 6 (d) to (f) are cross-sectional views showing the manufacturing method of the circuit body.

[0020] Figure 7 This is a diagram showing the area near the end of the first sheet-like component.

[0021] Figure 8 This is a variation 1 showing the details near the end of the first sheet-like member.

[0022] Figure 9 This is a modified example 2, which shows the details near the end of the first sheet-like member.

[0023] Figure 10It is a graph showing the relationship between the shrinkage of the sealing material and temperature.

[0024] Figure 11 (a) is a cross-sectional view of the circuit body in this embodiment, (b) is a cross-sectional view of Comparative Example 1, and (c) is a cross-sectional view of Comparative Example 2.

[0025] Figure 12 This is a semi-perspective top view of the power module in this embodiment.

[0026] Figure 13 This is the circuit diagram of the power module in this embodiment.

[0027] Figure 14 It is a circuit diagram of a power conversion device that uses circuit elements.

[0028] Figure 15 This is a three-dimensional view of the power conversion device.

[0029] Figure 16 yes Figure 15 A three-dimensional cross-sectional view of the XV-XV line of the power conversion device shown. Detailed Implementation

[0030] Hereinafter, 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; appropriate omissions and simplifications have been made for clarity. The present invention may also be implemented in various other ways. Unless otherwise specified, the constituent elements may be singular or plural.

[0031] To facilitate understanding of the present invention, the positions, sizes, shapes, and extents of the constituent elements shown in the accompanying drawings may not represent their actual positions, sizes, shapes, or extents. Therefore, the present invention is not limited to the positions, sizes, shapes, and extents disclosed in the accompanying drawings.

[0032] Figure 1 This is a top view of the circuit body 400 in this embodiment. Figure 2 It is circuit body 400. Figure 1 The cross-sectional view of line XX shown. Figure 3 It is circuit body 400. Figure 1 The cross-sectional view of the YY line is shown.

[0033] like Figure 1As shown, the circuit body 400 consists of three power modules 300 and a cooling component 340. The power modules 300 have the function of converting direct current and alternating current using semiconductor elements, and generate heat when energized. Therefore, a structure is formed in which refrigerant flows through the cooling component 340 for cooling. The refrigerant used is water or an antifreeze mixture of water and ethylene glycol. Alternatively, the cooling component 340 may also be configured with pin-shaped heat sinks vertically mounted on its base plate. The cooling component 340 is preferably made of aluminum, which has high thermal conductivity and is lightweight. The cooling component 340 is manufactured by extrusion molding, forging, brazing, etc.

[0034] The power module 300 has a capacitor module 500 connected to a DC circuit on one side (see below). Figure 14 The positive terminal 315B and negative terminal 319B are connected. On the other side of the positive terminal 315B and negative terminal 319B, there are electric generators 192 and 194 connected to the AC circuit (see below). Figure 14 The AC side terminal 320B and other power terminals that carry large currents are connected. Additionally, on the other side, there are signal terminals for power module control, such as the lower arm gate signal terminal 325L, mirror emitter signal terminal 325M, Kelvin emitter signal terminal 325K, upper arm gate signal terminal 325U, mirror emitter signal terminal 325M, and Kelvin emitter signal terminal 325K.

[0035] like Figure 2 As shown, the first power semiconductor element forming the upper arm circuit includes an active element 155 and a diode 156. The semiconductor material constituting the active element 155 can be, for example, Si, SiC, GaN, GaO, C, etc. When using a body diode for the active element 155, the diode 156 can be omitted. The collector side of the active element 155 and the cathode side of the diode 156 are bonded to a second conductor plate 431. A first conductor plate 430 is bonded to the emitter side of the active element 155 and the anode side of the diode 156. Solder or sintered metal can be used for these bonding processes. Furthermore, the first conductor plate 430 and the second conductor plate 431 are not particularly limited as long as they are materials with high electrical and thermal conductivity, but copper-based or aluminum-based materials are preferred. They can be used individually, or Ni or Ag plating can be applied to improve bonding with solder or sintered metal. To ensure insulation distance, the first conductor plate 430 has a recess on the outer periphery of the area where it connects with the first power semiconductor elements 155 and 156 (details to be described later). Figure 4 ).

[0036] On the first conductor plate 430, a cooling member 340 is closely connected through a first sheet member 440 and further through a heat conduction member 453. The first sheet member 440 is constructed by laminating a first resin insulating layer 442 and a metal foil 444, with the metal foil 444 side closely connected to the heat conduction member 453.

[0037] On the second conductor plate 431, a cooling member 340 is closely connected through a second sheet member 441 and further through a heat conduction member 453. The second sheet member 441 is constructed by laminating a second resin insulating layer 443 and a metal foil 444, with the metal foil 444 side closely connected to the heat conduction member 453.

[0038] like Figure 3 As shown, the second power semiconductor element forming the lower arm circuit includes an active element 157 and a diode 158 (described later). Figure 12 , Figure 13 Additionally, in Figure 3 In this configuration, diode 158 is positioned inside active element 157 along the X-axis. The collector side of active element 157 and the cathode side of diode 158 are connected to fourth conductor plate 433. Third conductor plate 432 is connected to emitter side of active element 157 and anode side of diode 158.

[0039] like Figure 2 As shown, the first sheet member 440 and the second sheet member 441 have an embedded portion C covered by a sealing material 360, a heat dissipation surface A that overlaps with the surfaces of the first conductor plate 430 and the second conductor plate 431, and a blank portion B that is the area between the embedded portion C and the heat dissipation surface A. The blank portion B is recessed into the interior of the circuit body 400 (in the Z-axis direction) than the heat dissipation surface A, and the embedded portion C is recessed into the interior of the circuit body 400 (in the Z-axis direction) than the blank portion B. Details will be described later.

[0040] like Figure 3 As shown, the first conductor plate 430, the second conductor plate 431, the third conductor plate 432, and the fourth conductor plate 433, in addition to their function of conducting electricity, also function as heat transfer components to transfer the heat generated by the first power semiconductor elements 155, 156, and the second power semiconductor elements 157, 158 to the cooling component 340. Because the potentials of each conductor plate 430, 431, 432, 433 and the cooling component 340 are different, therefore... Figure 2 As shown, a first sheet member 440 having a first resin insulating layer 442 is spaced between each conductor plate 430, 431, 432, 433 and the cooling member 340, and a second sheet member 441 having a second resin insulating layer 443 is spaced between them. A heat conduction member 453 is provided between each sheet member 440, 441 and the cooling member 340 to reduce contact thermal resistance.

[0041] There are no particular limitations on the material of the heat conduction component 453 as long as it has high thermal conductivity, but it is preferable to use a combination of high thermal conductivity materials such as metals, ceramics, and carbon-based materials with resin materials. This is because filling the space between the heat conduction component 453 and the cooling component 340, and between the heat conduction component 453 and each sheet component 440, 441 with resin material will reduce the contact thermal resistance.

[0042] The first power semiconductor elements 155 and 156, the second power semiconductor elements 157 and 158, the conductor plates 430, 431, 432, and 433, and the sheet members 440 and 441 are sealed by a sealing material 360 through transfer molding. The first resin insulating layer 442 and the second resin insulating layer 443 of each sheet member 440 and 441 are not particularly limited as long as they are materials that have adhesiveness to each conductor plate 430, 431, 432, and 433, but epoxy resin insulating layers with dispersed powdered inorganic fillers are preferred. This is because it provides a good balance between adhesion and heat dissipation. Each sheet member 440 and 441 can be a single resin insulating layer, but it is preferable to have a metal foil 444 on the side in contact with the heat-conducting member 453. In the transfer molding process, when the sheet-like components 440 and 441 are mounted on the mold, release tabs or metal foils 444 are provided on the contact surfaces between the sheet-like components 440 and 441 and the mold to prevent adhesion to the mold. Release tabs, due to their poor thermal conductivity, require a peeling process after transfer molding. However, with metal foils 444, by selecting copper-based or aluminum-based metals with high thermal conductivity, they can be used without peeling after transfer molding. By performing transfer molding including the sheet-like components 440 and 441, and with the ends of the sheet-like components 440 and 441 covered by sealing material 360, the reliability of the product is improved.

[0043] Figure 4 yes Figure 1 The cross-sectional perspective view of the power module 300 of the XX line shown indicates the state after removing the cooling component 340 from the circuit body 400. For example... Figure 4 As shown, the first sheet member 440 has an embedded portion C covered by a sealing material 360, a heat dissipation surface A that overlaps with the surface of the first conductor plate 430, and a blank portion B that forms the area between the embedded portion C and the heat dissipation surface A. The blank portion B is recessed into the power module 300 than the heat dissipation surface A, and the embedded portion C is recessed into the power module 300 than the blank portion B. Therefore, even if the circuit body 400 warps, the tightness between the cooling member 340 and the cooling member 340 can be ensured without compromising heat dissipation, even when the cooling member 340 is tightly attached to the first sheet member 440.

[0044] Figure 5 (a)~(c) Figure 6Figures (d) to (f) are cross-sectional views showing the manufacturing method of circuit element 400. The left side of each figure indicates... Figure 1 The cross-sectional view of one power module of the XX line shown is displayed on the right. Figure 1 The diagram shows a cross-sectional view of one power module of the YY line.

[0045] Figure 5 Figure (a) shows the welding and wire bonding processes. The collector side of the active element 155 (serving as a first power semiconductor element) and the cathode side of the diode 156 are connected on the second conductor plate 431, and the gate electrode of the active element 155 is connected via wire bonding. The emitter side of the active element 155 and the anode side of the diode 156 are connected to the first conductor plate 430. Similarly, the collector side of the active element 157 (serving as a second power semiconductor element) and the cathode side of the diode 158 are connected on the fourth conductor plate 433, and the gate electrode of the active element 157 is connected via wire bonding. The emitter side of the active element 157 and the anode side of the diode 158 are connected to the third conductor plate 432.

[0046] Figure 5 (b) is a diagram showing the mold setting process. The transfer molding device 601 vacuum-adheres the spring 602 and sheet members 440 and 441 onto the mold. The vacuum degassing mechanism for vacuum-adhereing the sheet members 440 and 441 onto the mold is omitted from the diagram. Inside the mold, which is preheated to a constant temperature of 175°C, the sheet members 440 and 441 are held in place by vacuum adsorption using a clamp. Here, the circuit body 310, preheated to 175°C, is placed inside the mold in a state away from the sheet members 440 and 441.

[0047] Figure 5 (c) is a diagram illustrating the transfer molding process. With the sheet members 440 and 441 separated from the circuit body 310, the upper and lower molds are brought close together, with only the gaskets (not shown) surrounding the upper and lower molds in contact. Next, a vacuum is applied to the mold cavity. When the vacuum is complete and the pressure reaches below a specified level, the upper and lower molds are fully tightened to further flatten the gaskets. At this point, the sheet members 440 and 441 are in contact with the circuit body 310. Under vacuum conditions, the sheet members 440 and 441 are in contact with the circuit body 310 and are tightly sealed by the pressure of the spring 602, thus ensuring a tight seal without entrainment in gaps.

[0048] Next, sealing material 360 is injected into the mold cavity. The mold used for transfer molding has a shape where the heat dissipation surface A and the blank portion B are on the same surface and do not recede inwards, while the embedded portion C recedes inwards compared to the heat dissipation surface A and the blank portion B. That is, in this process, the embedded portion C recedes inwards compared to the heat dissipation surface A and the blank portion B, and is sealed with sealing material 360. In other words, the heat dissipation surface A and the blank portion B are on the same surface and do not recede inwards, while the embedded portion C recedes inwards to seal.

[0049] Figure 6 (d) is a diagram showing the curing process. The power module 300, sealed with sealing material 360, is removed from the transfer molding device 601 and cooled at room temperature for at least 2 hours to cure. As a result, due to the curing shrinkage and cooling shrinkage of the sealing material 360, the remaining portion B recedes into the interior of the power module 300 compared to the heat dissipation portion A. The embedded portion C recedes into the interior of the power module 300 compared to the remaining portion B. In particular, the power module 300 has a capacitor module 500 (see below) on one side in the X-axis direction. Figure 14 The positive terminal 315B and negative terminal 319B are connected, and on the other side are electric generators 192 and 194 connected to the AC circuit (see below). Figure 14 The AC side terminal 320B and other power terminals are connected. Therefore, at both ends of the power module 300 in the X-axis direction, the amount of sealing material 360 increases. Through the curing shrinkage and cooling shrinkage of the sealing material 360, the effect of the blank part B being pushed back into the power module 300 is more significant than that of the heat dissipation surface A.

[0050] Figure 6 (e) is a diagram showing the installation process of the cooling member 340. The cooling member 340 is attached to the two surfaces of the power module 300 through the heat conduction member 453. Thus, the cooling member 340 is in close contact with the first sheet member 440 and the second sheet member 441 through the heat conduction member 453.

[0051] Figure 6 (f) is a diagram showing the circuit body 400 manufactured through the above processes. Thus, cooling components 340 are provided on both sides of the power module 300 to manufacture the circuit body 400.

[0052] Figure 7 It means Figure 5 (c) shows a view near the end of the first sheet member 440 in the transfer molding process. Figure 7 In the diagram, the first sheet member 440 is indicated by a dashed line. The first sheet member 440 is pressed onto the first conductor plate 430 by the transfer molding device 601. Then, it is sealed with sealing material 360.

[0053] Because the embedded portion C of the sheet member 440 is recessed further inward than the blank portion B, the end of the sheet member 440 is covered by the sealing material 360 in the embedded portion C. Then, in the embedded portion C, the sealing material 360 and the resin flash composed of the resin component of the sealing material 360 are prevented from flowing into the blank portion B between the sheet member 440 and the mold.

[0054] The sheet member 440 is vacuum-adhered to the mold of the transfer molding device 601, but its adsorption force is much smaller than the molding pressure Pa of the injection of the sealing material 360. Furthermore, the adsorption force weakens further when the interior of the mold containing the sealing material 360 is vented due to vacuum molding. Therefore, between the sheet member 440 and the mold of the transfer molding device 601, the sealing material 360 and resin flash composed of the resin component of the sealing material 360 flow from the outer periphery (end) 440-1 of the sheet member 440. If the mold is processed to create a protrusion 601-1 slightly inward from the outer periphery (end) 440-1 of the sheet member 440, the sealing material 360 or resin flash stops at this protrusion 601-1.

[0055] The principle behind stopping the sealing material 360 or resin flash at the protrusion 601-1 will be explained. For example... Figure 7As shown, during the process of the sealing material 360 flowing into the mold, firstly, the molding pressure Pa generated by the flowing sealing material 360 presses the sheet member 440 onto the mold. Then, after the mold is substantially filled with the sealing material 360, a final molding pressure Pa, which is larger than before, is applied to the sealing material 360 as hydrostatic pressure. At this time, the sealing material 360 also flows into the tiny gap, and the sealing material 360 and resin flash flow from the outer periphery (end) 440-1 of the sheet member 440 into the narrow gap between the sheet member 440 and the mold. However, due to the narrow gap, the pressure Pb of the sealing material 360 flowing in is lost. If there is a protrusion 601-1 before the sealing material 360 flows into the gap between the sheet member 440 and the mold, the pressure Pb of the sealing material 360 flowing into the narrow gap between the sheet member 440 and the mold acts in the opposite direction to the molding pressure Pa that presses the sheet member 440 onto the mold. At this point, the molding pressure Pa, which presses the sheet member 440 onto the mold, is higher than the pressure Pb due to the flow in the narrow gap. Therefore, the sealing material 360 flowing between the sheet member 440 and the mold is stopped by the protrusion 601-1. In particular, when the protrusion 601-1, which is close to a right angle, is a very small part, the molding pressure Pa, which presses the sheet member 440 onto the mold, completely counteracts the pressure Pb, which causes the sealing material 360 to flow into the narrow gap between the sheet member 440 and the mold. Therefore, it works very effectively in stopping the sealing material 360 or resin flash. Thus, in the embedded part C, the outer periphery (end) 440-1 of the sheet member 440 is covered by the sealing material 360 or resin flash.

[0056] And, through Figure 6 In the curing process shown in (d), the blank portion B is recessed inward compared to the heat dissipation surface A, and the buried portion C is recessed inward compared to the blank portion B. Therefore, even if warping occurs on the circuit body 400, as detailed below, the heat dissipation surface A can be pressed against the cooling member 340 with a higher surface pressure.

[0057] Figure 8 This is a variation of Example 1, a diagram showing details near the end of the first sheet-like member 440. In Figure 8 In the diagram, the first sheet-like member 440 is indicated by a dashed line. The first sheet-like member 440 is disposed between the first conductor plate 430 and the cooling member 340. Furthermore, through... Figure 6 In the curing process shown in (d), the blank portion B is recessed inward compared to the heat dissipation surface A, and the embedded portion C is recessed inward compared to the blank portion B. In this modified example 1, an example is shown in which the blank portion B is recessed sharply inward compared to the heat dissipation surface A through the curing process, but such a shape is also possible.

[0058] Figure 9This is variation 2, a diagram showing details near the end of the first sheet-like member 440. In Figure 9 In the diagram, the first sheet-like member 440 is indicated by a dashed line. The first sheet-like member 440 is disposed between the first conductor plate 430 and the cooling member 340. Furthermore, through... Figure 6 In the curing process shown in (d), the blank portion B is recessed inward compared to the heat dissipation surface A, and the embedded portion C is recessed inward compared to the blank portion B. In this modified example 2, an example is shown in which the blank portion B gradually recedes inward as it leaves the heat dissipation surface A through the curing process, but such a shape is also possible.

[0059] In addition to variations 1 and 2, as long as the blank portion B is recessed inward compared to the heat dissipation surface A, and the buried portion C is recessed inward compared to the blank portion B, for example, although the illustration is omitted, a groove can also be formed on the blank portion B.

[0060] Figure 10 This is a graph showing the relationship between the shrinkage of the sealing material (360°) and temperature. The horizontal axis represents temperature, and the vertical axis represents shrinkage.

[0061] For example, at a Tmold temperature of 175°C, sealing material 360 is injected into the mold of the transfer molding device 601. Using the dimensions immediately after injection as a reference, note the shrinkage in the Z-axis direction of the components of the power module 300. When viewing the components from the emitter side to the collector side of the active elements 155 and 157 of the power module 300, they are: a first sheet component 440, a first conductor plate 430 and a third conductor plate 432, solder, first power semiconductor elements 155 and 156 and second power semiconductor elements 157 and 158, solder, a second conductor plate 431 and a fourth conductor plate 433, and a second sheet component 441. Each sheet component 440 and 441 is formed by laminating a resin insulating layer with a thickness of 100 μm to 500 μm and a metal foil with a thickness of 30 μm to 200 μm. Each conductor plate 430 and 431 is made of a copper-based material with a thickness of 1 mm to 5 mm. The solder is made of tin-based material with a thickness of 50 μm to 200 μm. The first power semiconductor elements 155 and 156 and the second power semiconductor elements 157 and 158 are made of silicon-based material with a thickness of 80 μm to 200 μm.

[0062] Although composed of various materials, in this embodiment, the thickest constituent material, namely copper-based material, is used as a representative, and the shrinkage in the Z-axis direction of these constituent components is approximately described using the thermal shrinkage of pure copper. After being injected into the mold of the transfer molding device 601, the sealing material 360 cures and shrinks as the curing reaction proceeds. The amount of curing shrinkage varies depending on the composition of the sealing material 360. It varies depending on the proportion of epoxy resin components undergoing the curing reaction and the proportion of other fillers that do not undergo the curing reaction; the higher the proportion of epoxy resin components, the greater the curing shrinkage. Even if the proportion of epoxy resin components is the same, the greater the proportion of epoxy groups, which are reactive components, in the epoxy resin components, the greater the curing shrinkage. The power module 300, removed from the mold of the transfer molding device 601, is cooled to room temperature.

[0063] like Figure 10 As shown in the sealing materials α and γ, when the glass transition temperatures αt and γt are lower than Tmold, they shrink with a large amount of shrinkage up to the glass transition temperatures αt and γt, respectively. If the temperature is lower than the glass transition temperatures αt and γt, they shrink with a smaller amount of shrinkage.

[0064] like Figure 10 As shown in the diagram, the sealing material β shrinks by a certain amount when its glass transition temperature is higher than Tmold. T1 is the minimum operating ambient temperature of the power module 300, and T2 is the maximum operating ambient temperature; for example, T1 is -40°C and T2 is 125°C. Within this temperature range, when the shrinkage is greater than that of copper Cu, that is, when the shrinkage of the sealing material 360 enters... Figure 10 In the case of the shaded area H shown, within the operating temperature range T1-T2, the blank portion B recedes inward compared to the heat dissipation surface A. The sealing materials β and γ correspond to this, becoming the sealing material 360 used in this embodiment. Sealing material β is, for example, a multifunctional epoxy resin (66 vol% silica filler). Sealing material γ is, for example, a phenolic varnish-type epoxy resin (66 vol% silica filler). Since sealing material α indicates that the heat dissipation surface A recedes inward compared to the blank portion B, it does not conform to the sealing material 360 used in this embodiment.

[0065] The difference in shrinkage between the sealing material 360 and Cu recedes into the interior of the circuit body 400 in the Z-axis direction. That is, the shrinkage of the sealing material 360 with respect to temperature is greater than that of the first conductor plate 430, the second conductor plate 431, the third conductor plate 432, and the fourth conductor plate 433. Therefore, in the normal operating temperature range, the blank portion B and the buried portion C recede into the interior of the circuit body 400 more than the heat dissipation portion A.

[0066] Furthermore, the difference in shrinkage between the sealing material 360 and Cu results in warping in the XY direction. Generally, the second conductor plate 431 and the fourth conductor plate 433 on the collector side of the circuit body 400 typically have a larger volume than the first conductor plate 430 and the third conductor plate 432 on the emitter side. When the shrinkage of the sealing material 360 is greater than that of Cu, the sealing material 360 shrinks more than Cu. If comparing the collector side and the emitter side, the emitter side, which occupies a larger proportion of the sealing material 360, shrinks more than the collector side, resulting in a warping concave shape on the emitter side.

[0067] In the case of a circuit 400 with a single-sided cooling structure where the cooling member 340 is located on one side, even if the emitter side is recessed, the possibility of problems arising from heat dissipation from the collector side is small. In the case of a circuit 400 with a double-sided cooling structure where the cooling member 340 is located on both sides, the warping caused by the emitter side recess increases the distance between the heat dissipation surface A on the emitter side and the cooling member 340, and the heat dissipation performance may decrease.

[0068] Figure 11 (a) is a cross-sectional view of the circuit body 400 of this embodiment. Figure 11 (b) is a cross-sectional view of Comparative Example 1. Figure 11 (c) is a cross-sectional schematic diagram of Comparative Example 2. Both indicate the case where a warping Q with an emitter-side depression occurs.

[0069] like Figure 11 As shown in (a), in this embodiment, the blank portion B is recessed inward compared to the heat dissipation surface A, and the buried portion C is recessed inward compared to the blank portion B. Therefore, even if a warpage Q occurs on the circuit body 400, the end of the sealing material 360 will not come into contact with the cooling member 340, and the heat dissipation surface A will be in close contact with the cooling member 340. Therefore, it has an excellent heat dissipation effect. In particular, the warpage Q of the circuit body 400 is significant in the X-axis direction of the circuit body 400, but the amount of sealing material 360 increases at both ends of the circuit body 400 in the X-axis direction. Through the curing shrinkage and cooling shrinkage of the sealing material 360, the blank portion B is recessed inward compared to the heat dissipation surface A into the power module 300.

[0070] On the other hand, such as Figure 11 As shown in (b), in Comparative Example 1, the blank portion B and the buried portion C do not recede further inward than the heat dissipation surface A. Therefore, when warping Q occurs on the circuit body 400, the end of the sealing material 360 abuts against the cooling member 340, thus increasing the distance between the cooling member 340 and the heat dissipation surface A, resulting in poor heat dissipation.

[0071] In addition, such as Figure 11As shown in (c), in Comparative Example 2, the buried portion C is recessed inwards compared to the blank portion B, but the blank portion B is not recessed inwards compared to the heat dissipation surface A. Therefore, when warping Q occurs on the circuit body 400, the sealing material 360 near the end of the blank portion B comes into contact with the cooling member 340, thus creating a gap between the cooling member 340 and the heat dissipation surface A, resulting in poor heat dissipation.

[0072] Figure 12 This is a semi-perspective top view of the power module 300 in this embodiment. Figure 13 This is a circuit diagram of the power module 300 in this embodiment.

[0073] like Figure 12 , Figure 13 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 signal terminal 325U is induced from the gate and emitter of the active element 155 of the upper arm circuit. The negative side terminal 319B is output from the emitter side of the lower arm circuit and connected to the negative side of the battery or capacitor or GND. The lower arm gate signal terminal 325L is induced from the gate and emitter 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 not connected to GND, but to the negative side of the capacitor.

[0074] Furthermore, a first conductor plate (emitter side of the upper arm circuit) 430 and a second conductor plate (collector side of the upper arm circuit) 431 are arranged above and below the active element 155 and diode 156 of the first power semiconductor element (upper arm circuit). A third conductor plate (emitter side of the lower arm circuit) 432 and a fourth conductor plate (collector side of the lower arm circuit) 433 are arranged above and below the active element 157 and diode 158 of the second power semiconductor element (lower arm circuit).

[0075] The power module 300 in this embodiment has a 2-in-1 structure that integrates the upper arm circuit and the lower arm circuit into a single module. Alternatively, a structure that integrates multiple upper arm circuits and lower arm circuits into a single module can also be used. In this case, the number of output terminals from the power module 300 can be reduced, thus achieving miniaturization.

[0076] Figure 14 This is a circuit diagram of the power conversion device 200 using circuit body 400.

[0077] The power conversion device 200 includes inverter circuits 140 and 142, an auxiliary inverter circuit 43, and a capacitor module 500. Inverter circuits 140 and 142 are configured by a circuit body 400 (not shown) containing multiple power modules 300, which are connected to form a three-phase bridge circuit. In cases of high current capacity, the power modules 300 are further connected in parallel. By performing these parallel connections corresponding to each phase of the three-phase inverter circuit, the increased current capacity can be accommodated. Furthermore, by connecting the power semiconductor elements built into the power modules 300, namely active elements 155 and 157 and diodes 156 and 158, in parallel, the increased current capacity can also be accommodated.

[0078] Inverter circuit 140 and inverter circuit 142 have the same basic circuit structure, and their control methods and operations are also basically the same. Since the general outline of the circuit operation of inverter circuit 140, etc., is well known, detailed descriptions are omitted here.

[0079] As described above, the upper arm circuit includes an active element 155 and an upper arm diode 156 as power semiconductor elements for switching, and the lower arm circuit includes an active element 157 and a lower arm diode 158 as power semiconductor elements for switching. The active elements 155 and 157 receive drive signals output from one or the other of the two drive circuits constituting the drive circuit 174 to perform switching operations, converting the DC power supplied from the battery 136 into three-phase AC power.

[0080] As described above, the active element 155 for the upper arm and the active element 157 for the lower arm include 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 each include two electrodes: a cathode electrode and an anode electrode. Figure 13 As shown, 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. Therefore, the current flow from the emitter electrodes of the active element 155 (upper arm) and the active element 157 (lower arm) toward the collector electrodes becomes positive.

[0081] Alternatively, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) can be used as an active element, in which case the diode 156 for the upper arm and the diode 158 for the lower arm are not needed.

[0082] The positive terminal 315B and negative terminal 319B of each upper and lower arm series circuit are connected to the DC terminals 362A and 362B of the capacitor module 500, respectively. Alternating current 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 terminal 320B of each power module 300. The AC terminal 320B of each power module 300 of each phase is connected to the AC output terminal of the power conversion device 200, and the generated AC power is supplied to the stator windings of the electric generator 192 or 194.

[0083] The control circuit 172 generates timing signals 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 sensor (e.g., current sensor 180) on the vehicle side. The drive circuit 174 generates drive signals for switching 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. Additionally, 181, 182, and 188 are connectors.

[0084] The upper and lower arm series circuit includes a temperature sensor (not shown), and the temperature information of the upper and lower arm series circuit is input to the control circuit 172. Additionally, the voltage information of the DC positive terminal of the upper and lower arm series circuit is input to the control circuit 172. Based on this information, the control circuit 172 performs over-temperature and over-voltage detection. If over-temperature or over-voltage is detected, the switching of all active components 155 for the upper arm and active components 157 for the lower arm is stopped, protecting the upper and lower arm series circuit from the effects of over-temperature or over-voltage.

[0085] Figure 15 yes Figure 14 The diagram shows a perspective view of the power conversion device 200. Figure 16 yes Figure 15 A three-dimensional cross-sectional view of the XV-XV line of the power conversion device 200 shown.

[0086] like Figure 15As shown, the power conversion device 200 has a frame 12, which is composed of a lower housing 11 and an upper housing 10, and is formed into a generally rectangular parallelepiped shape. Inside the frame 12 are housed circuit components 400, capacitor modules 500, etc. The circuit component 400 has a cooling flow path, and a cooling water inlet pipe 13 and a cooling water outlet pipe 14, which communicate with the cooling flow path, protrude from one side of the frame 12. The lower housing 11 has an opening on its upper side (Z direction), and the upper housing 10 is mounted on the lower housing 11, blocking the opening. The upper housing 10 and the lower housing 11 are formed of aluminum alloy or the like and are fixed in a sealed manner relative to the outside. Alternatively, the upper housing 10 and the lower housing 11 can be integrally formed. By making the frame 12 a simple rectangular parallelepiped shape, installation in vehicles, etc., becomes easier, and productivity is also improved.

[0087] A connector 17 is mounted on one side of the housing 12 along its length, and an AC terminal 18 is connected to the connector 17. In addition, a connector 21 is provided on the surface of the cooling water inlet pipe 13 and the cooling water outlet pipe 14.

[0088] like Figure 16 As shown, a circuit body 400 is housed within the housing 12. A control circuit 172 and a drive circuit 174 are positioned above the circuit body 400, and a capacitor module 500 is housed on the DC terminal side of the circuit body 400. By positioning the capacitor module at the same height as the circuit body 400, the power conversion device 200 can be made thinner, increasing its flexibility in vehicle installation. The AC terminal 320B of the circuit body 400 passes through the current sensor 180 and is connected to the busbar. Furthermore, the DC terminals of the circuit body 400, namely the positive terminal 315B and the negative terminal 319B, are respectively connected to the positive and negative terminals of the capacitor module 500. Figure 13 Connect the DC terminals 362A and 362B.

[0089] The following effects can be obtained by implementing the methods described above.

[0090] (1) The circuit body 400 includes: a power semiconductor element 155; a first conductor plate 430 connected to one side of the power semiconductor element 155; a first sheet member 440 having a first resin insulating layer 442 and at least covering the surface of the first conductor plate 430; a sealing material 360 sealing the ends of the power semiconductor element 155, the first conductor plate 430, and the first sheet member 440; and a first cooling member 340 in close contact with the first sheet member 440. The first sheet member 440 has an embedded portion C whose ends are covered by the sealing material 360, a heat dissipation surface A that overlaps with the surface of the first conductor plate 430, and a blank portion B that is the area between the embedded portion C and the heat dissipation surface A. The blank portion B is recessed inward compared to the heat dissipation surface A, and the embedded portion C is recessed inward compared to the blank portion B. Thus, even if warping occurs in the circuit body, the tightness between the member and the cooling member can be ensured, and heat dissipation is not compromised.

[0091] (2) The manufacturing method of the circuit body 400 comprises the following steps: First step, sealing a power semiconductor element 155, a first conductor plate 430 connected to one side of the power semiconductor element 155, and a first sheet member 440 having a first resin insulating layer 442 and at least covering the surface of the first conductor plate 430 with a sealing material 360. The first sheet member 440 has an embedded portion C whose end is covered by the sealing material 360, a heat dissipation surface A overlapping the surface of the first conductor plate 430, and a blank portion B between the embedded portion C and the heat dissipation surface A. The embedded portion C is recessed inwards compared to the heat dissipation surface A and the blank portion B, and then sealed with the sealing material 360. Second step, curing and shrinking the sealing material 360, causing the blank portion B to recede inwards compared to the heat dissipation surface A. Third step, making the cooling member 340 in close contact with the first sheet member 440. Thus, even if warping occurs in the circuit body, the tightness between the cooling member and the cooling member can be ensured, without compromising heat dissipation.

[0092] This invention is not limited to the above-described embodiments. Other methods that can be considered within the scope of the technical concept of this invention, as long as they do not impair the features of this invention, are also included within the scope of this invention.

[0093] Symbol Explanation

[0094] 10…Upper housing, 11…Lower housing, 13…Cooling water inlet pipe, 14…Cooling water outlet pipe, 17…Connector, 18…AC terminal, 21…Connector, 43, 140, 142…Inverter circuit, 155…First power semiconductor element (upper arm circuit active element), 156…First power semiconductor element (upper arm circuit diode), 157…Second power semiconductor element (lower arm circuit active element), 158…Second power semiconductor element (lower arm circuit diode), 172…Control circuit, 174…Drive circuit, 180…Current sensor, 181, 182, 188…Connectors, 192, 194…Electric generator, 200…Power conversion device, 300…Power module, 310…Circuit body, 315B…Positive side terminal, 319B…Negative side terminal, 320B…AC side terminal, 325K…Open 325L… Lower arm gate signal terminal, 325M… Mirror emitter signal terminal, 325U… Upper arm gate signal terminal, 340… Cooling component, 360… Sealing material, 400… Circuit body, 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 sheet component (emitter side), 441… Second sheet component (collector side), 442… First resin insulating layer (emitter side), 443… Second resin insulating layer (collector side), 444… Metal foil, 453… Heat conduction component, 500… Capacitor module, 601… Transfer molding device, 602… Spring, A… Heat dissipation surface, B… Remaining portion, C… Embedded portion.

Claims

1. A circuit element, characterized in that, It comprises: a power semiconductor element; a first conductor plate connected to one side of the power semiconductor element; a first sheet member having a first resin insulating layer and at least covering the surface of the first conductor plate; a sealing material sealing the ends of the power semiconductor element, the first conductor plate, and the first sheet member; and a first cooling member in close contact with the first sheet member. The first sheet-like member has: a buried portion including the end of the first sheet-like member and covered by the sealing material; a heat-dissipating surface portion as a region overlapping with the first conductor plate and whose surface is exposed from the sealing material; and a blank portion as a region between the buried portion and the heat-dissipating surface portion and whose surface is exposed from the sealing material. The heat dissipation surface and the remaining portion of the first sheet member protrude from the surface of the sealing material covering the embedded portion, and the protrusion height of the remaining portion of the first sheet member relative to the surface of the sealing material covering the embedded portion is lower than that of the heat dissipation surface.

2. The circuit body according to claim 1, characterized in that, It comprises: a second conductor plate connected to the other side of the power semiconductor element; a second sheet member having a second resin insulating layer and at least covering the surface of the second conductor plate; and a second cooling member in close contact with the second sheet member. The sealing material seals the ends of the second conductor plate and the second sheet-like member. The second sheet-like member has: a recessed portion comprising the second sheet-like member and the end of which is covered by the sealing material; a heat-dissipating surface portion, which overlaps with the second conductor plate and whose surface is exposed from the sealing material; and a blank portion, which is the area between the recessed portion and the heat-dissipating surface portion and whose surface is exposed from the sealing material. The heat dissipation surface and the remaining portion of the second sheet member protrude from the surface of the sealing material covering the embedded portion, and the protrusion height of the remaining portion of the second sheet member relative to the surface of the sealing material covering the embedded portion is lower than that of the heat dissipation surface.

3. The circuit body according to claim 1, characterized in that, The first sheet-like component is formed by stacking the first resin insulating layer and the first metal foil. The first cooling component is in close contact with the heat dissipation surface of the first sheet component through the first metal foil.

4. The circuit body according to claim 2, characterized in that, The second sheet-like component is formed by stacking the second resin insulating layer and the second metal foil. The second cooling component is in close contact with the heat dissipation surface of the second sheet component through the second metal foil.

5. The circuit body according to claim 1, characterized in that, The first cooling component is in close contact with the first sheet-like component through the heat conduction component.

6. The circuit body according to claim 2, characterized in that, The second cooling component is in close contact with the second sheet-like component through the heat conduction component.

7. The circuit body according to claim 1 or 3, characterized in that, The shrinkage of the sealing material with respect to temperature is greater than that of the first conductor plate with respect to temperature.

8. The circuit body according to claim 2 or 4, characterized in that, The shrinkage of the sealing material with respect to temperature is greater than that of the second conductor plate with respect to temperature.

9. The circuit body according to claim 1 or 2, characterized in that, have: A first terminal, which extends from the power semiconductor element and is connected to a capacitor; and The second terminal is led out from the power semiconductor element on the side opposite to the first terminal and is connected to the motor.

10. A power conversion device, characterized in that, It is composed of any one of the circuit bodies in claims 1 to 9, and converts DC power into AC power.

11. A method for manufacturing a circuit element, characterized in that, It consists of the following processes: The first step is to seal a power semiconductor element, a first conductor plate connected to one side of the power semiconductor element, and a first sheet member having a first resin insulating layer and at least covering the surface of the first conductor plate with a sealing material. The first sheet member has: a buried portion including the end of the first sheet member covered by the sealing material; a heat dissipation surface portion as a region overlapping with the first conductor plate and whose surface is exposed from the sealing material; and a blank portion as a region between the buried portion and the heat dissipation surface portion and whose surface is exposed from the sealing material. The power semiconductor element, the first conductor plate, and the first sheet member are sealed with the sealing material such that the buried portion is covered by the sealing material, and the heat dissipation surface portion and the blank portion protrude from the surface of the sealing material covering the buried portion. The second step involves curing and shrinking the sealing material, causing the protrusion height of the remaining portion relative to the surface of the sealing material covering the embedded portion to become lower than that of the heat dissipation surface; and The third step involves making the cooling component and the first sheet-like component in close contact.

12. The method for manufacturing a circuit element according to claim 11, characterized in that, The third step includes the step of making the cooling component and the first sheet component in close contact through the heat conduction component.

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