Power conversion device, and method for manufacturing power conversion device

Abstract

This power conversion device comprises: a plurality of semiconductor packages that have a first heat dissipation surface and a second heat dissipation surface, a semiconductor element being incorporated between the first heat dissipation surface and the second heat dissipation surface; a printed wiring board on which the plurality of semiconductor packages are mounted on one surface; a plurality of heat dissipation members that thermally connect to the first heat dissipation surface; a holding member that holds the plurality of heat dissipation members so as to allow for relative displacement, and that presses the second heat dissipation surface toward the one surface of the printed wiring board with the plurality of heat dissipation members therebetween; and a secondary heat dissipation member that is disposed on the other surface of the printed wiring board, said other surface being on the opposite side to the one surface, and said secondary heat dissipation member facing the second heat dissipation surface. The holding member is fixed to the one surface of the printed wiring board and supports the secondary heat dissipation member disposed on the other surface of the printed wiring board.

Description

Power conversion device and method for manufacturing the same

[0001] The present invention relates to a power converter and a method for manufacturing the power converter.

[0002] As inverter main circuits using printed wiring boards become smaller, improvements in the cooling performance of semiconductor packages mounted on the printed wiring boards are required. To improve cooling performance, it is important for each semiconductor package to be able to conform to the cooling structure. As an example of a configuration that ensures conformance of components, Patent Document 1 listed below discloses a power module configuration in which a step absorbing section and a buffer spacer contract and deform so as to absorb thickness variations and tilts due to the pressing force applied when the wiring board and the heat dissipation member are fastened together.

[0003] Japanese Patent Application Laid-Open No. 2022-057425

[0004] In the technology described in Patent Document 1, a contractile heat transfer member is interposed between the power module and the heat dissipation fins. However, to accommodate thickness variations and tilts between the power modules, the heat transfer member itself must be thick, which increases thermal resistance and reduces heat dissipation. Furthermore, if the heat transfer member is made thin enough to avoid reducing heat dissipation, excessive stress is generated at the terminal joints of the semiconductor package, resulting in vibration resistance issues. In light of this, the present invention aims to provide a power conversion device that achieves improved heat dissipation, improved vibration resistance, miniaturization, and improved reliability.

[0005] The power conversion device includes a plurality of semiconductor packages having a first heat dissipation surface and a second heat dissipation surface, each having a semiconductor element built in between the first heat dissipation surface and the second heat dissipation surface; a printed wiring board on one side of which the plurality of semiconductor packages are mounted; a plurality of heat dissipation members thermally connected to the first heat dissipation surface; a holding member that holds the plurality of heat dissipation members so that they can be displaced relative to each other and presses the second heat dissipation surface toward the one side of the printed wiring board via the plurality of heat dissipation members; and a secondary heat dissipation member that is arranged on the other side of the printed wiring board, which is the opposite side to the one side, and faces the second heat dissipation surface, and the holding member is fixed to the one side of the printed wiring board and supports the secondary heat dissipation member that is arranged on the other side of the printed wiring board.

[0006] It is possible to provide a power conversion device that achieves improved heat dissipation, improved vibration resistance, miniaturization, and improved reliability.

[0007] 1A and 1B are cross-sectional views of a power converter according to an embodiment of the present invention, and are diagrams illustrating a method for manufacturing a power converter according to an embodiment of the present invention.

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and some omissions and simplifications have been made as appropriate for clarity of explanation. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0009] In order to facilitate understanding of the invention, the position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0010] (One embodiment and overall configuration) (FIG. 1) A power conversion device 100 has a plurality of semiconductor packages 1, a printed wiring board 2, a holding member 3, and a secondary heat dissipation member 4. The power conversion device 100 has a double-sided cooling structure for the semiconductor packages 1 by mounting the plurality of semiconductor packages 1 on the printed wiring board 2 and arranging and fixing the holding members 3 and the secondary heat dissipation members 4 on both sides of the printed wiring board 2 so as to face the surface of the printed wiring board 2.

[0011] The semiconductor package 1 includes a semiconductor element and a conductive member, each of which is sealed with a sealing member such as resin, thereby insulating the semiconductor element from its surroundings and protecting it from foreign matter. The semiconductor element may be an IGBT, MOSFET, diode, or the like.

[0012] The conductive members of the semiconductor package 1 are made of a material with low electrical resistance, such as copper. The semiconductor package 1 also has terminals 1c for electrically connecting to a printed wiring board 2. Within the semiconductor package 1, the semiconductor element is electrically connected to the conductive members and terminals 1c via connection wiring such as bonding wires or conductive bonding materials such as solder. The terminals 1c and conductive members of the semiconductor package 1 are each electrically connected to one surface 2a of the printed wiring board 2 by conductive bonding materials such as solder, thereby forming a power conversion circuit.

[0013] Each of the semiconductor packages 1 has a first heat dissipation surface 1a on one side and a second heat dissipation surface 1b on the other side as heat dissipation surfaces for cooling the semiconductor element. The semiconductor package 1 also has a semiconductor element built in between the first heat dissipation surface 1a and the second heat dissipation surface 1b.

[0014] In the semiconductor package 1, the first heat dissipation surface 1a and the second heat dissipation surface 1b are exposed surfaces of the conductive member that are exposed from the sealing member. This improves the heat dissipation performance of the semiconductor element. The first heat dissipation surface 1a is a heat dissipation surface formed on the side where the bonding area between the semiconductor element and the conductive member is large. The second heat dissipation surface 1b is a heat dissipation surface formed on the side where the bonding area between the semiconductor element and the conductive member is small.

[0015] The first heat dissipation surface 1a of the semiconductor package 1 is thermally connected to a heat dissipation member 6, such as a movable fin, via a heat conduction member 5, which is a thermally conductive member such as a heat dissipation sheet or heat dissipation grease that can be displaced relative to the heat dissipation member 6. The heat conduction member 5 may be configured, for example, by combining an insulating member with high insulation properties, such as a ceramic plate, with an insulating material that reduces contact thermal resistance, such as heat dissipation grease, which is softer than the ceramic plate, with insulating materials disposed on both sides of the insulating member. The heat dissipation member 6 is made of a material with high thermal conductivity, such as aluminum or copper. This configuration improves the insulation and heat dissipation properties of the semiconductor package 1.

[0016] The holding member 3 has a frame 3c and a holding member cover 3d. The frame 3c is formed as a single piece and is integrated with the auxiliary heat dissipation member fixing portion 3a and the substrate fixing portion 3b, which will be described later. A plurality of heat dissipation members 6 are respectively attached to the frame 3c. The holding member cover 3d is, for example, in the form of a leaf spring, and is attached to the frame 3c so as to cover the heat dissipation members 6. By attaching the holding member cover 3d and the plurality of heat dissipation members 6 to the frame 3c, a refrigerant flow path 8 is formed within the holding member 3.

[0017] The heat dissipation member 6 is provided with fins and pins on the surface that comes into contact with the refrigerant that is pumped by a pump (not shown) and flows through the refrigerant flow path 8. This increases the surface area that comes into contact with the refrigerant, thereby improving heat dissipation. The heat dissipation member 6 is held by the holding member 3 so that it can be relatively displaced.

[0018] An elastic seal member 6a having elasticity is provided at the portion where the heat dissipation member 6 is fitted into the frame 3c. This ensures sealing of the refrigerant flow path 8 when the heat dissipation member 6 is displaced relative to the holding member 3.

[0019] The holding member 3 presses the first heat dissipation surface 1a of the semiconductor package 1 toward one surface 2a of the printed wiring board 2 via the plurality of heat dissipation members 6. This not only cools the plurality of semiconductor packages 1 from the first heat dissipation surface 1a, but also presses the heat dissipation member 6 toward the printed wiring board 2 and causes relative displacement due to the elastic force of the holding member 3 and the elastic sealing member 6a, eliminating the need to increase the thickness of the heat conduction member 5 to ensure compliance, thereby achieving a thinner heat conduction member 5 and improved heat dissipation.

[0020] The printed wiring board 2 has an insulating resin layer and a layer of board wiring 11. The insulating layers and the layers of board wiring 11 through which current flows are alternately stacked, thereby insulating the layers of board wiring 11 from each other. The board wiring 11 also has current supply wiring that supplies current to the semiconductor packages 1. This current supply wiring is formed in a position between the multiple semiconductor packages 1 in the planar direction of the printed wiring board 2. A sub-heat dissipation member 4, which will be described later, overlaps the position where the current supply wiring is formed in the thickness direction of the printed wiring board 2. This enables the cooling performance of the current supply wiring through which a large current flows to be improved in the printed wiring board 2.

[0021] The board wiring 11 electrically connects the semiconductor package 1 mounted on one surface 2a of the printed wiring board 2 to electronic components (not shown) on the printed wiring board 2. The one surface 2a of the printed wiring board 2 is connected to the second heat dissipation surface 1b of the semiconductor package 1 with a conductive bonding material such as solder. The semiconductor package 1 is metal-bonded to the current supply wiring of the printed wiring board 2 on the second heat dissipation surface 1b, so that current is supplied to the semiconductor package 1 from the current supply wiring. This configuration improves the wiring current density of the board wiring 11.

[0022] The board wiring 11 of the printed wiring board 2 is laminated to form multiple layers, which increases the cross-sectional area of ​​copper and allows a larger current to flow. The printed wiring board 2 has multiple thermal vias 9 on the surface facing the second heat dissipation surface 1b of the semiconductor package 1. The thermal vias 9 penetrate the printed wiring board 2 in the thickness direction. The multiple laminated layers of the board wiring 11 are electrically connected to each other by the thermal vias 9. This improves heat transfer from one surface 2a to the other surface 2b of the printed wiring board 2, and improves heat dissipation from the semiconductor package 1 to the secondary heat dissipation member 4 via the thermal vias 9.

[0023] A secondary heat dissipation member 4 is disposed on the other surface 2b of the printed wiring board 2, which is the surface opposite to the one surface 2a. The secondary heat dissipation member 4 includes a frame 4a, a cover 4b, a thermally conductive member 5, and a heat dissipation member 6, and faces the second heat dissipation surface 1b of the semiconductor package 1 via the printed wiring board 2. With this configuration, the multiple semiconductor packages 1 are cooled from the second heat dissipation surface 1b side.

[0024] In addition, the heat conduction member 5 arranged between the heat dissipation member 6 assembled to the auxiliary heat dissipation member 4 and the printed wiring board 2 is a heat conduction member similar to the heat conduction member 5 arranged between the heat dissipation member 6 assembled to the holding member 3 described above and the first heat dissipation surface 1a of the semiconductor package 1.

[0025] The other surface 2b of the printed wiring board 2 is thermally connected to the auxiliary heat dissipation member 4 via a heat conduction member 5. The auxiliary heat dissipation member 4 has a cover 4b and a heat dissipation member 6 attached to a single frame 4a, thereby forming a refrigerant flow path 8 therein. The refrigerant flowing through the refrigerant flow path 8 in the auxiliary heat dissipation member 4 cools the printed wiring board 2 and the semiconductor package 1 via the heat conduction member 5.

[0026] In this configuration, the holding member 3 is fixed to one surface 2a of the printed wiring board 2, presses the first heat dissipation surface 1a of the semiconductor package 1 via the relatively displaceable heat dissipation member 6, and supports the auxiliary heat dissipation member 4 arranged on the other surface 2b of the printed wiring board 2. As a result, the second heat dissipation surface 1b of the semiconductor package 1 is cooled by the refrigerant flowing through the refrigerant flow path 8 of the auxiliary heat dissipation member 4 via the printed wiring board 2.

[0027] The above-described configuration provides the following advantages. In a conventional configuration in which the printed wiring board 2 is not provided between the semiconductor packages 1 and the auxiliary heat dissipation member 4, stress is applied to each semiconductor package 1, resulting in issues with the vibration resistance of the terminals 1c of each semiconductor package 1 and the ability to conform between the semiconductor packages 1. However, in the present invention, stress is applied to the auxiliary heat dissipation member 4 supported by the printed wiring board 2, distributing and reducing the stress applied to the terminals 1c of the semiconductor packages 1, thereby improving vibration resistance. Furthermore, by holding the semiconductor packages 1 from the holding member 3 side so that they can be displaced relative to each other, the conformability between the semiconductor packages 1 is ensured. Furthermore, by forming the heat conduction member 5 uniformly thin, thermal resistance can be reduced, thereby improving heat dissipation performance. Furthermore, the vibration resistance, heat dissipation performance, and reliability of the power conversion device 100 can be improved without impeding the function of the main heat dissipation path in the semiconductor packages 1. The ability to ensure conformability contributes to miniaturization and cost reduction.

[0028] (Manufacturing Method) (FIG. 2) The manufacturing process of the power conversion device 100 will be described. As shown in FIG. 2(a), first, the semiconductor package 1 is bonded and mounted on the printed wiring board 2 by a method such as reflow mounting, with the second heat dissipation surface 1b (see FIG. 1) of the semiconductor package 1 facing one surface 2a of the printed wiring board 2.

[0029] Furthermore, after the heat dissipation members 6 are assembled to the holding member 3 and the refrigerant flow paths 8 are formed in the holding member 3 to hold the heat dissipation members 6 so that they can be relatively displaced, the thermally conductive members 5 are pre-positioned on the surfaces that are in thermal contact with the first heat dissipation surfaces 1a of the semiconductor packages 1. Then, as shown by the arrows in FIG. 2A , the printed wiring board 2 and the semiconductor packages 1 are fixed to the holding member 3 so that one surface 2a of the printed wiring board 2 and the first heat dissipation surfaces 1a of the semiconductor packages 1 face the holding member 3. Specifically, this is a process in which the printed wiring board 2 on which the semiconductor packages 1 are mounted is fastened to the board fixing portions 3b of the holding member 3 with bolts 7 or the like. This thermally connects the plurality of heat dissipation members 6 to the first heat dissipation surfaces 1a.

[0030] 2(b), when fixing the auxiliary heat dissipation member 4 to the holding member 3, a thermally conductive member 5 is placed in advance on either the other surface 2b of the printed wiring board 2 or the auxiliary heat dissipation member 4. Then, the auxiliary heat dissipation member 4 is fixed to the other surface 2b, which is the surface opposite to the one surface 2a of the printed wiring board 2, and to the holding member 3. Specifically, this is a step in which the auxiliary heat dissipation member 4 is fastened to the auxiliary heat dissipation member fixing portion 3a of the holding member 3 with bolts 7 or the like.

[0031] 2(a) and 2(b), the heat dissipation members 6 are held in a relatively displaceable manner by being pressed independently of one another by the holding member cover 3d, which is a pressure mechanism, for each corresponding semiconductor package 1. Note that between the holding member cover 3d and each heat dissipation member 6, a coil spring or elastic rubber material (not shown) is disposed as an independent pressure mechanism, and may be separate from or integrated with the holding member cover 3d.

[0032] By pressing each of the heat dissipation members 6 using independent pressure mechanisms, the holding member 3 holds the multiple heat dissipation members 6 so that they can be displaced relative to each other, and presses the first heat dissipation surface 1a of the semiconductor package 1 toward one surface 2a of the printed wiring board 2 via the multiple heat dissipation members 6, and supports the secondary heat dissipation member 4.

[0033] This reduces height variations between each semiconductor package 1, ensures tracking ability, and since the heat dissipation members 6 placed on both sides of each semiconductor package 1 are each formed thin, heat dissipation performance can also be improved.

[0034] (Fig. 3) Fig. 3(a) is a plan view seen from direction A in Fig. 1, and Fig. 3(b) is a plan view seen from direction B in Fig. 1. By mounting a plurality of semiconductor packages 1 on a printed wiring board 2, the packages can be electrically connected in series or in parallel, and Fig. 3(a) shows an example in which two semiconductor packages 1 are connected in series and two in parallel to form a three-phase power conversion circuit.

[0035] Fixing portions 2d, into which fastening members or the like (not shown) are inserted to fix the printed wiring board 2, are provided near the ends of the printed wiring board 2. This improves the vibration resistance of the printed wiring board 2. Furthermore, auxiliary heat dissipation member holding portions 2c, into which fastening members or the like are inserted to fasten the auxiliary heat dissipation member 4 to the printed wiring board 2, are provided near the position where the heat dissipation member 6 is disposed. This makes it possible to suppress deformation of the holding member 3 and the auxiliary heat dissipation member 4 due to pressing force.

[0036] In addition, it is desirable that the board fixing portion 2d and the auxiliary heat dissipation member holding portion 2c of the printed wiring board 2 be located outside the area where the heat dissipation member 6 is arranged in the vertical direction (short direction of the printed wiring board 2) in Figure 3 so as not to interfere with the refrigerant flow path 8.

[0037] 3(b) is provided for each of the plurality of semiconductor packages 1 shown in Fig. 3(a), so that even if the height of the heat dissipation surface varies among the plurality of semiconductor packages 1, the heat dissipation members 6 can follow the variations and apply pressure, ensuring conformance and contributing to improved heat dissipation. Note that if the degree of variation in height among the semiconductor packages 1 is small, the heat dissipation members 6 shown in Fig. 3(b) may be combined into one heat dissipation member 6 and used to press the plurality of semiconductor packages 1 together.

[0038] In this way, the first heat dissipation surface 1a of the semiconductor package 1 is pressed by the heat dissipation member 6, and the second heat dissipation surface 1b of the semiconductor package 1 is supported by the auxiliary heat dissipation member 4 via the printed wiring board 2, thereby making it possible to thin the heat conduction member 5 on the first heat dissipation surface 1a side and reducing thermal resistance, and by dissipating heat from the second heat dissipation surface 1b to the auxiliary heat dissipation member 4 via the heat conduction member 5 and the printed wiring board 2, the heat dissipation performance of the semiconductor package 1 is improved and contributes to miniaturization and cost reduction.

[0039] According to the embodiment of the present invention described above, the following advantageous effects are achieved.

[0040] (1) A power conversion device 100 includes a plurality of semiconductor packages 1 each having a first heat dissipation surface 1 a and a second heat dissipation surface 1 b and incorporating a semiconductor element between the first heat dissipation surface 1 a and the second heat dissipation surface 1 b, a printed wiring board 2 on one side 2 a of which the plurality of semiconductor packages 1 are mounted, a plurality of heat dissipation members 6 thermally connected to the first heat dissipation surface 1 a, a holding member 3 that holds the plurality of heat dissipation members 6 so as to be relatively displaceable and presses the second heat dissipation surface 1 b toward the one side 2 a of the printed wiring board 2 via the plurality of heat dissipation members 6, and a secondary heat dissipation member 4 that is disposed on the other side 2 b of the printed wiring board 2 opposite the one side 2 a and faces the second heat dissipation surface 1 b, and the holding member 3 is fixed to the one side 2 a of the printed wiring board 2 and supports the secondary heat dissipation member 4 that is disposed on the other side 2 b of the printed wiring board 2. This configuration makes it possible to provide a power conversion device 100 that achieves improved heat dissipation performance, improved vibration resistance, miniaturization, and improved reliability.

[0041] (2) The printed wiring board 2 has a plurality of thermal vias 9 on the surface facing the semiconductor package 1. This improves the heat dissipation performance to the secondary heat dissipation member 4.

[0042] (3) The printed wiring board 2 has board wiring 11 through which a current flows, and the board wiring 11 has current supply wiring that supplies a current to the semiconductor package 1, and the semiconductor package 1 is metal-bonded to the current supply wiring at the second heat dissipation surface 1b. This improves the wiring current density of the board wiring 11.

[0043] (4) The current supply wiring is formed in a position between the plurality of semiconductor packages 1 in the planar direction, and the sub-heat dissipation member 4 overlaps the position where the current supply wiring is formed in the thickness direction of the printed wiring board 2. This makes it possible to improve the heat dissipation performance of the current supply wiring through which a large current flows.

[0044] (5) The holding member 3 includes a frame 3c to which the plurality of heat dissipation members 6 are respectively attached, and a holding member cover 3d that covers the frame 3c and the heat dissipation members 6. This configuration makes it possible to ensure uniformity in height between the heat dissipation members 6 and to allow the heat dissipation members 6 to move relative to each other, which contributes to making the heat dissipation members 6 thinner.

[0045] (6) The heat dissipation members 6 are pressed by independent pressure mechanisms for each corresponding semiconductor package 1. This improves the height conformity between the semiconductor packages 1, thereby improving heat dissipation performance.

[0046] (7) A thermally conductive heat conduction member 5 is disposed between the holding member 3 and the heat dissipation member 6, and between the printed wiring board 2 and the auxiliary heat dissipation member 4. The heat conduction member 5 includes an insulating member with high insulation properties and insulating materials that are softer in heat conduction than the insulating member and disposed on both sides of the insulating member. This improves the height conformability between the semiconductor packages 1, thereby improving heat dissipation performance.

[0047] (8) A method for manufacturing a power conversion device 100 including: a plurality of semiconductor packages 1 each having a first heat dissipation surface 1a and a second heat dissipation surface 1b and incorporating a semiconductor element between the first heat dissipation surface 1a and the second heat dissipation surface 1b; a printed wiring board 2; a plurality of heat dissipation members 6; a holding member 3 to which the plurality of heat dissipation members 6 are attached and which cools the plurality of semiconductor packages from the first heat dissipation surface 1a; and a sub-heat dissipation member 4 to cool the plurality of semiconductor packages 1 from the second heat dissipation surface 1b, wherein the plurality of semiconductor packages 1 are attached to the printed wiring board 2 with the second heat dissipation surface 1b side facing one surface 2a of the printed wiring board 2. By mounting the printed wiring board 2 on the plate 2, the plurality of heat dissipation members 6 and the first heat dissipation surface 1a are thermally connected, the printed wiring board 2 is fixed to the holding member 3 so that one side 2a of the printed wiring board 2 faces the holding member 3, and the auxiliary heat dissipation member 4 is fixed to the other side 2b of the printed wiring board 2, which is the side opposite to the one side 2a, and to the holding member 3, so that the holding member 3 holds the plurality of heat dissipation members 6 so that they can be relatively displaced, and presses the first heat dissipation surface 1a via the plurality of heat dissipation members 6 toward the one side of the printed wiring board 2, thereby supporting the auxiliary heat dissipation member 4. By adopting such a manufacturing method, it is possible to provide a power conversion device 100 that achieves improved heat dissipation performance, improved vibration resistance, miniaturization, and improved reliability.

[0048] The present invention is not limited to the above-described embodiments, and various modifications and combinations of other configurations are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited to those having all of the configurations described in the above-described embodiments, and includes those in which some of the configurations are omitted.

[0049] REFERENCE SIGNS LIST 1 semiconductor package 1a first heat dissipation surface 1b second heat dissipation surface 1c terminal 2 printed wiring board 2a one side 2b other side 2c auxiliary heat dissipation member holding portion 2d fixing portion 3 holding member 3a auxiliary heat dissipation member fixing portion 3b board fixing portion 3c frame 3d holding member cover 4 auxiliary heat dissipation member 4a frame 4b cover 5 heat conduction member 5a first heat conduction member 5b second heat conduction member 6 heat dissipation member 6a elastic seal member 7 bolt 8 refrigerant flow path 9 thermal via 11 board wiring 100 power conversion device

Claims

1. A power conversion device comprising: a plurality of semiconductor packages each having a first heat dissipation surface and a second heat dissipation surface, each having a semiconductor element embedded between the first heat dissipation surface and the second heat dissipation surface; a printed wiring board on one side of which the plurality of semiconductor packages are mounted; a plurality of heat dissipation members thermally connected to the first heat dissipation surface; a holding member that holds the plurality of heat dissipation members so that they can be relatively displaced and presses the first heat dissipation surface toward the one side of the printed wiring board via the plurality of heat dissipation members; and a secondary heat dissipation member that is arranged on the other side of the printed wiring board, which is the surface opposite to the one side, and faces the second heat dissipation surface, wherein the holding member is fixed to the one side of the printed wiring board and supports the secondary heat dissipation member that is arranged on the other side of the printed wiring board.

2. The power conversion device according to claim 1, wherein the printed wiring board has a plurality of thermal vias on a surface facing the semiconductor package.

3. The power conversion device according to claim 2, wherein the printed wiring board has board wiring through which a current flows, the board wiring has current supply wiring that supplies a current to the semiconductor package, and the semiconductor package is metal-bonded to the current supply wiring at the second heat dissipation surface.

4. A power conversion device as described in claim 3, wherein the current supply wiring is formed at a position between a plurality of semiconductor packages in a planar direction, and the secondary heat dissipation member overlaps the position where the current supply wiring is formed in the thickness direction of the printed wiring board.

5. The power conversion device according to claim 1, wherein the holding member comprises a frame to which each of the plurality of heat dissipation members is attached, and a holding member cover that covers the frame and the heat dissipation members.

6. The power conversion device according to claim 5, wherein the plurality of heat dissipation members are pressed by independent pressure mechanisms for the respective semiconductor packages.

7. A power conversion device as described in claim 1, wherein a heat-conducting member having thermal conductivity is arranged between the holding member and the heat dissipation member, and between the printed wiring board and the secondary heat dissipation member, and the heat-conducting member comprises an insulating member having high insulating properties and an insulating material having thermal conductivity softer than the insulating member, arranged on both sides of the insulating member.

8. A method for manufacturing a power conversion device comprising: a plurality of semiconductor packages having a first heat dissipation surface and a second heat dissipation surface, each having a semiconductor element built in between the first heat dissipation surface and the second heat dissipation surface; a printed wiring board; a plurality of heat dissipation members; a holding member to which the plurality of heat dissipation members are assembled and which cools the plurality of semiconductor packages from the first heat dissipation surface; and a sub-heat dissipation member which cools the plurality of semiconductor packages from the second heat dissipation surface, the method comprising: mounting the plurality of semiconductor packages on the printed wiring board with the second heat dissipation surface side facing one side of the printed wiring board, thereby thermally connecting the plurality of heat dissipation members and the first heat dissipation surface; fixing the printed wiring board to the holding member so that the one side of the printed wiring board faces the holding member; A method for manufacturing a power conversion device in which the secondary heat dissipation member is fixed to the other side of the printed wiring board, which is the side opposite to the one side, and to the holding member, so that the holding member holds the multiple heat dissipation members so that they can be displaced relative to each other, and presses the first heat dissipation surface toward the one side of the printed wiring board via the multiple heat dissipation members, thereby supporting the secondary heat dissipation member.

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