Power conversion device and method for manufacturing power conversion device

Abstract

This power conversion device is provided with: a semiconductor element; a heat transfer plate connected to the semiconductor element; a semiconductor module formed by molding the semiconductor element and the heat transfer plate with a resin; a semi-solid heat conduction material which is in contact with the heat transfer plate and is arranged so as to cover one surface of the semiconductor module; and a heat dissipation member that dissipates heat from the semiconductor module via the heat conduction material.

Description

Technical Field

[0001] The present invention provides a power conversion device and a method for manufacturing the power conversion device. Background Art

[0002] The power conversion device with a double-sided cooling structure is provided with a thermally conductive material such as TIM (Thermal Interface Material) between the cooling water channel as a heat dissipation component, but the reliability of the device may be reduced depending on the contact condition between the thermally conductive material and the lead frame (heat transfer plate) of the semiconductor module. In addition, the power conversion device is also required to reduce costs and improve production efficiency.

[0003] Patent Document 1 listed below discloses a device having a structure in which a heat transfer layer is provided on the upper surface of a semiconductor element to effectively dissipate heat generated by the semiconductor element to the outside. Prior art literature Patent Literature

[0004] Patent Document 1: Patent Publication No. 5740995 Summary of the invention Problem that the invention aims to solve

[0005] In the structure described in Patent Document 1, the TIM as a heat transfer layer (heat conductive material) may be pumped out, thereby causing problems such as increased thermal resistance or reduced insulation. In view of this, an object of the present invention is to provide a power conversion device and a method for manufacturing a power conversion device that achieves cost reduction, improved production efficiency, and improved reliability. Technical means of solving problems

[0006] The power conversion device comprises: a semiconductor element; a heat transfer plate connected to the semiconductor element; a semiconductor module formed by molding the semiconductor element and the heat transfer plate with a resin; a semi-solid heat conductive material in contact with the heat transfer plate and arranged in a manner covering one surface of the semiconductor module; and a heat dissipation component for dissipating heat from the semiconductor module via the heat conductive material. In addition, as a method for manufacturing a power conversion device, the following method is adopted: a heat transfer plate connected to a semiconductor element is molded with a resin to form a semiconductor module, a part of the molded resin on one surface of the formed semiconductor module is removed to form a step portion that exposes the surface of the heat transfer plate and is formed in a manner to surround the surface of the heat transfer plate, a semi-solid heat conductive material and a heat dissipation member are assembled to the semiconductor module, the semi-solid heat conductive material is in contact with the exposed surface of the heat transfer plate and is arranged in a manner to cover the molded resin on the one surface, and the heat dissipation member dissipates heat from the semiconductor module via the heat conductive material. Effects of the Invention

[0007] It is possible to provide a power conversion device and a method for manufacturing a power conversion device that achieve cost reduction, improved production efficiency, and improved reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a circuit diagram of a power conversion device. Figure 2 This is an overall diagram of a power conversion device. Figure 3 It is a cross-sectional view of a power conversion device according to one embodiment of the present invention. Figure 4 It is a diagram for explaining a first method of manufacturing a power conversion device. Figure 5 It is a diagram for explaining the second method of manufacturing the power conversion device. Figure 6 It is a diagram for explaining the positional relationship between the first heat conductive material and the semiconductor module. Figure 7 It is a diagram for explaining the positional relationship between the second heat conductive material and the semiconductor module. DETAILED DESCRIPTION

[0009] 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, and appropriate omissions and simplifications have been made for clarity of the description. The present invention may also be implemented in various other ways. Unless otherwise specified, each constituent element may be singular or plural.

[0010] 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.

[0011] (One embodiment and overall structure of the present invention) ( Figure 1 ) In the power conversion device 100, a plurality of circuit bodies 1 constituting a power conversion circuit are each constituted by a semiconductor element such as an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). Two circuit bodies 1 connected in series and one capacitor 2 form a pair, each forming a power conversion circuit of one phase. The three-phase power conversion circuit is connected to a positive wiring 3 and a negative wiring 4, respectively.

[0012] The circuit body 1 (semiconductor module 1) has three terminals: a high-voltage side terminal for the main circuit (a collector terminal if it is an IGBT, a drain terminal if it is a MOSFET), a low-voltage side terminal for the main circuit (an emitter terminal if it is an IGBT, a source terminal if it is a MOSFET), and a control terminal (gate terminal).

[0013] ( Figure 2 ) The power conversion device 100 includes: a plurality of circuit bodies 1 each having a plurality of power semiconductor elements, a wiring substrate 6 (hereinafter referred to as the substrate 6) electrically connected to the circuit bodies 1 and having a plurality of positive wirings 3 and negative wirings 4 stacked one on another in the thickness direction, and a plurality of smoothing capacitors 2 provided in correspondence with the plurality of circuit bodies 1. The positive wirings 3 and negative wirings 4 are arranged in the thickness direction ( Figure 2 The capacitors 2 and the circuit body 1 of each phase are connected (for details, see Figures 4 to 7 (described later in the text).

[0014] Figure 2 The following configuration example is shown: the circuit bodies 1 are arranged in parallel for every 4, and the positive wiring 3 and the negative wiring 4 are arranged opposite to each other in the middle, so that 8 circuit bodies 1 are used as a 1-phase circuit, and 3 phases are provided on the substrate 6. In this way, the circuit body 1 can also be set as a multi-parallel connection configuration according to the desired output current value. Similarly, in order to meet the capacitor capacity determined by the desired input voltage fluctuation amount, the capacitor 2 can also be connected to the substrate 6 in multi-parallel.

[0015] The substrate 6 has a plurality of conductor layers in the thickness direction, and each conductor layer is stacked with a resin layer interposed therebetween. A positive wiring 3, a negative wiring 4, an output wiring 7, and a signal wiring 9 are formed on the conductor layer of the substrate 6. The circuit body 1 and the capacitor 2 are connected to the positive wiring 3 and the negative wiring 4 through a bonding material such as solder. The circuit body 1 has a signal terminal 8 for connecting to the signal wiring 9. The positive wiring 3, the negative wiring 4, and the output wiring 7 are each formed thicker than the signal wiring 9 connected to the circuit body 1, and have a structure to cope with a current larger than that of other wirings for supplying a current to a load at a connection destination.

[0016] The positive wiring 3 and the negative wiring 4 have through-holes 5 (hereinafter referred to as through-holes 5). The through-holes 5 are provided in the regions where the positive wiring 3 and the negative wiring 4 of each phase are not stacked on each other. A plurality of positive wirings 3 or negative wirings 4 are respectively penetrated in the thickness direction of the substrate 6 to form through-holes 5, whereby wirings of the same potential are electrically connected to each other. Thus, the regions where the through-holes 5 are not provided suppress the reduction of the cross-sectional areas of the positive wiring 3 and the negative wiring 4, and the regions where the through-holes 5 are provided suppress the positive wiring 3 and the negative wiring 4 from being cut off.

[0017] In addition, when a blind hole is used as the through hole 5, the upper surface ( Figure 2 The first and second layers starting from the front surface of the substrate are used as positive wiring 3, and the third and fourth layers are used as negative wiring 4, so that the positive wiring 3 and the negative wiring 4 can be stacked without reducing the cross-sectional area of ​​the positive wiring 3 and the negative wiring 4.

[0018] The positive wiring 3 is connected to the positive terminal of a DC voltage source such as a battery (not shown), and the negative wiring 4 is connected to the negative terminal of a DC voltage source such as a battery (not shown). Thus, a DC voltage is supplied to the circuit of each phase.

[0019] In order to satisfy the capacitor capacitance determined by the desired input voltage variation, the capacitor 2 is arranged and connected along the substrate 6 and has a positive terminal 10 and a negative terminal 11 as terminals for connecting to the positive wiring 3 and the negative wiring 4 of the substrate 6 .

[0020] The positive terminal 10 of the capacitor 2 is connected to the positive wiring 3, thereby being electrically connected to the main circuit high-voltage side terminal of the circuit body 1 on the high side (upper arm). In addition, the positive wiring 3 is connected to the positive terminal 10 of the capacitor 2 of the other phase and the main circuit high-voltage side terminal of the circuit body 1 on the high side of the other phase. The negative terminal 11 of the capacitor 2 is connected to the negative wiring 4, thereby being connected to the main circuit low-voltage side terminal of the circuit body 1 on the low side (lower arm). The negative wiring 4 is connected to the negative terminal 11 of the capacitor 2 of the other phase and the main circuit low-voltage side terminal 12 of the low-side circuit body 1 of the other phase. The main circuit low-voltage side terminal of the circuit body 1 on the high side is connected to the main circuit high-voltage side terminal of the circuit body 1 on the low side through the output wiring 7 of each phase. The output wiring 7 of each phase is connected to a load such as a motor not shown.

[0021] The control terminal of the circuit body 1 is connected to a control circuit (not shown) and is turned on or off according to a signal input from a higher-level control device such as a microcomputer, thereby outputting an AC voltage to a load such as a motor.

[0022] ( Figure 3 ) Figure 3 1 is a cross-sectional view showing the structure of a circuit body 1 (hereinafter referred to as a semiconductor module 1). The semiconductor module 1 includes a semiconductor element 23 and a heat transfer plate 20 (lead frame 20). The semiconductor element 23 and the heat transfer plate 20 are molded by a resin 24 (resin). The semiconductor element 23 is connected to the heat transfer plate 20 via solder on both sides of its chip. In addition, the connection between the semiconductor element 23 and the heat transfer plate 20 is not limited to solder, and a sintered material, a mixed material of metal and resin, etc. can also be used. The gate pad (not shown) on the upper surface of the chip of the semiconductor element 23 is connected to the lead terminal 12 by wire bonding 13.

[0023] The lead terminals 12 protruding from the heat transfer plate 20 are connected to the substrate 6 by solder. Figure 3 The upper heat transfer plate 20 (source side) is referred to as a first heat transfer plate 20 a , and the lower side is referred to as a second heat transfer plate 20 b .

[0024] Two heat-conducting materials 21a and 21b are arranged on the upper surface of the first heat transfer plate 20a. The heat-conducting materials 21a and 21b are, for example, TIM. The heat-conducting materials 21a and 21b are semi-solid heat-conducting materials that are in contact with the first heat transfer plate 20a and are arranged to cover one surface of the semiconductor module 1. The semi-solid heat-conducting material is a heat-conducting material that is made of a material such as a filler or grease and whose shape is deformed by pressing.

[0025] The heat conductive materials 21a and 21b are in contact with the insulating sheet 22 on the surface (surface of the second heat conductive material 21b) opposite to the surface (surface of the first heat conductive material 21a) in contact with the heat transfer plate 20a. The insulating sheet 22 is in contact with the first cooling water channel 26a on the surface opposite to the surface in contact with the second heat conductive material 21b. Due to such a structure, the heat generated from the semiconductor module 1 is dissipated by the first cooling water channel 26a as a heat dissipation member via the heat conductive materials 21a and 21b.

[0026] In addition, the semiconductor module 1 has a step portion 24a formed so as to surround the first heat conductive material 21a on one surface (upper surface side) in contact with the heat conductive materials 21a and 21b. The step portion 24a is formed by processing a part of the mold resin 24 at the upper surface end of the semiconductor module 1. Figure 3 The heat conductive material 21a and 21b are two convex shapes in the cross-sectional view. Of the heat conductive materials 21a and 21b, the first heat conductive material 21a is arranged on the inner side of the step portion 24a, so as to be surrounded by the step portion 24a. On the other hand, the second heat conductive material 21b has a larger area than the first heat conductive material 21a. In addition, from the viewpoint of demoldability, when the convex portion of the step portion 24a is formed by demolding, the draft angle of the mold is preferably 3 degrees or more.

[0027] After trial production and research, it was found that the height of the semiconductor module 1 including the heat transfer plate 20 to which the chip of the semiconductor element 23 is soldered has a deviation within a range of less than 100 μm. Therefore, from the viewpoint of thermal resistance and material cost, it is preferred that the thickness of the first heat conductive material 21a is 100 μm or less. In addition, from the viewpoint of pumping, making the second heat conductive material 21b as thin as possible can reduce thermal resistance, but at the same time, it is also necessary to absorb the deviation in the height of the upper surface of the step portion 24a of the semiconductor module 1 mounted on the substrate 6. Therefore, the thickness of the second heat conductive material 21b is preferably 100 μm or less.

[0028] The semiconductor module 1 is located below the substrate 6 ( Figure 3 The substrate 6 is in contact with the third heat conducting material 21c via the heat transfer plate 20b. Figure 3 The lower surface of the semiconductor module 1 contacts the heat sink 25. The heat sink 25 contacts the second cooling water channel 26b on the surface opposite to the surface in contact with the substrate 6. Due to such a structure, both surfaces of the semiconductor module 1 are covered with the heat conductive materials 21a, 21b, 21c, and the heat generated from the semiconductor module 1 and the substrate 6 is dissipated by the cooling water channels 26a, 26b arranged to sandwich the semiconductor module 1 from both sides.

[0029] Alternatively, the first heat conductive material 21 a and the second heat conductive material 21 b , which are two heat conductive materials, may be integrated into one heat conductive material 21 and disposed on one surface of the semiconductor module 1 .

[0030] (First method for manufacturing a power conversion device) ( Figure 4 ) Figure 4 (a) is a diagram showing an example of the first manufacturing method, Figure 4 (b) is the resin molding flow Figure 4 FIG. 2 is a diagram of a mold (a) after solidification. A semiconductor element 23 is connected to the first heat transfer plate 20a by welding, and the semiconductor element 23 is wire-bonded 13 to the lead terminal 12. In addition, a semi-solid first heat conductive material 21a is arranged between the frame of the mold 28 and the first heat transfer plate 20a so as to be in contact with the first heat transfer plate 20a. As described above, after the heat transfer plates 20a, 20b, the semiconductor element 23, and the first heat conductive material 21a are set in the mold 28, transfer molding is performed using the resin 24. As a result, a semiconductor module 1 having a step portion 24a on one surface and an exposed surface of the first heat transfer plate 20a can be formed.

[0031] In this way, before resin molding, the state where the first heat conductive material 21a is arranged is set in the mold 28, so that no gap is generated between the first heat transfer plate 20 and the mold 28, and overmolding that increases thermal resistance can be prevented. In addition, the grinding or cleaning process to eliminate overmolding caused by the state where the first heat conductive material 21a is not arranged before resin molding is simplified. In addition, it is possible to prevent metal pieces and residues from remaining after cleaning, the reduction of insulation, and the peeling of the first heat conductive material 21a. In this way, the manufacturing method of the present invention can provide a semiconductor module 1 in which one electrode surface of the heat transfer plate 20 is exposed at the stage where resin molding is completed.

[0032] The semiconductor module 1 manufactured by this manufacturing method is mounted on the substrate 6, the second heat-conducting material 21b is further in contact with the upper surface (one surface) of the semiconductor module 1, and the third heat-conducting material 21c is in contact with the lower surface (the other surface), and the insulating sheets 22 are attached to each other, and finally, the cooling water paths 26a and 26b are sandwiched from the top and bottom. Thus, the power conversion device 100 is completed.

[0033] Conventionally, when a semiconductor module 1 without a step portion 24a is formed after resin molding, pumping out or voids are formed, which causes a problem of increased thermal resistance. However, by assembling the semiconductor module 1 using the manufacturing method of the present invention, the first heat conductive material 21a is sandwiched by the step portion 24a, and the second heat conductive material 21b is arranged on the upper surface thereof, so that pumping out of the second heat conductive material 21b can be suppressed.

[0034] (Second method for manufacturing power conversion device) ( Figure 5 ) Figure 5 (a)~ Figure 5 (c) is a diagram illustrating the second manufacturing method. Figure 5 In (a), the semiconductor element 23 and the lead terminal 12 connected to the first heat transfer plate 20a and the second heat transfer plate 20b, respectively, are mounted in the mold 28. At this time, a gap 28a is generated between the heat transfer plate 20a and the mold 28 due to the deviation of the solder thickness or the inclination of the first heat transfer plate 20a.

[0035] Then, in Figure 5 In (b), the resin 24 is flowed into the mold 28 to perform transfer molding. Figure 5 In the gap 28a above the first heat transfer plate 20a shown in (a), a semiconductor module 1 can be formed, and the semiconductor module 1 is formed with a portion covered with the mold 24b. Figure 5 In (c), only the resin 24 covered with the overmold 24b on the upper side of the heat transfer plate 20a, which is a part of the molded resin 24 on one surface of the semiconductor module 1, is removed by, for example, a laser decapsulator 27. By performing this step, a semiconductor module 1 can be provided in which the step portion 24a provided so as to surround the heat transfer plate 20a is formed and one electrode surface of the heat transfer plate 20a is exposed.

[0036] The semi-solid heat-conductive materials 21a and 21b that are in contact with the exposed surface of the heat transfer plate 20a of the semiconductor module 1 and are arranged so as to cover one surface, and the cooling water channels 26a and 26b, which are heat dissipation members that dissipate heat from the semiconductor module 1 via the heat-conductive materials 21a and 21b, are assembled onto the manufactured semiconductor module 1. Thereby, the power conversion device 100 of the present invention can be provided.

[0037] ( Figure 6 ) In the resin 24 of the semiconductor module 1, the following relationship holds between the stepped portion 24a and the first heat-conductive material 21a. Let the widths of the stepped portion 24a in the direction having the lead terminals 12 be a1 and a2 from the left of Figure 6 , and let the widths of the stepped portion 24a in the direction without the lead terminals 12 be b1 and b2 from the top of Figure 6 . At this time, a1 > b1 or a1 > b2. In addition, a2 > b1 or a2 > b2. Thus, in the past, a part of the heat-conductive material 21 pumped out by the second heat-conductive material 21b fell between the lead terminals 12, resulting in a problem of reduced insulation. However, according to the present invention, the heat-conductive material 21 is difficult to be pumped out, and the resistance of the cooling water channel 26 becomes large. In addition, even if the heat-conductive material 21b is pumped out and falls, since it preferentially falls to the side without the lead terminals 12, the insulation will not decrease.

[0038] ( Figure 7 ) Regarding the second heat-conductive material 21b in contact with the upper surface of the semiconductor module 1, the following relationship holds for the length of the second heat-conductive material 21b protruding from the stepped portion 24a of the semiconductor module 1. Let the distances that the second heat-conductive material 21b protrudes from the stepped portion 24a in the direction having the lead terminals 12 be c1 and c2 from the left of Figure 7 , and let the distances that the second heat-conductive material 21b protrudes from the stepped portion 24a in the direction without the lead terminals 12 be d1 and d2 from the top of Figure 7 . At this time, 0 < c1 < d1 or 0 < c1 < d2. In addition, 0 < c2 < d1 or 0 < c2 < d2. Thus, even if the second heat-conductive material 21b is pumped out and falls, it will preferentially fall to the side without the lead terminals 12, so the insulation of the lead terminals 12 will not decrease.

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

[0040] (1) A power conversion device 100 is provided which comprises: a semiconductor element 23; heat transfer plates 20a and 20b connected to the semiconductor element 23; a semiconductor module 1 formed by molding the semiconductor element 23 and the heat transfer plates 20a and 20b with a resin 24; semi-solid heat conducting materials 21a and 21b which are arranged in contact with the heat transfer plates 20a and 20b and cover one surface of the semiconductor module 1; and a heat dissipation member 26 which dissipates heat from the semiconductor module via the heat conduction materials 21a and 21b. Thus, it is possible to provide a power conversion device 100 which can achieve cost reduction, improved productivity, and improved reliability.

[0041] (2) The semiconductor module 1 has a step portion 24a formed on one surface in contact with the semi-solid heat-conducting materials 21a and 21b so as to surround a portion of the heat-conducting materials 21a and 21b (the first heat-conducting material 21a). Thus, it is possible to provide a semiconductor module 1 in which pumping is suppressed and one electrode surface of the heat transfer plate 20a is exposed.

[0042] (3) The heat-conductive material 21 includes: a first heat-conductive material 21a disposed so as to be surrounded by a step portion 24a; and a second heat-conductive material 21b in contact with the first heat-conductive material 21a and having a larger area than the first heat-conductive material 21a. Thus, both surfaces of the semiconductor module 1 are covered with the heat-conductive material 21, and the heat generated from the semiconductor module 1 and the substrate 6 is dissipated by the cooling water channels 26a and 26b disposed so as to sandwich the semiconductor module 1 from both surfaces.

[0043] (4) The first heat conductive material 21a and the second heat conductive material 21b are integrally arranged on one surface of the semiconductor module 1. This improves the connectivity between the first heat conductive material 21a and the second heat conductive material 21b, and contributes to the heat dissipation of the semiconductor module 1.

[0044] (5) One surface of the semiconductor module 1 is exposed to the surface of the heat conductive material 21a, and the other surface of the semiconductor module 1 is in contact with a third heat conductive material 21c different from the heat conductive material 21a, and the third heat conductive material 21c is in contact with a second heat dissipation member 26b different from the heat dissipation member 26a on the surface opposite to the surface in contact with the semiconductor module 1. Thus, it is possible to provide a power conversion device 100 in which the semiconductor module 1 is cooled on both sides.

[0045] (6) As a method for manufacturing a power conversion device 100 of the present invention, heat transfer plates 20a and 20b connected to a semiconductor element 23 are molded with a resin 24 to form a semiconductor module 1, a portion of the molded resin 24 on one surface of the formed semiconductor module 1 is removed to form a step portion that exposes the surface of the heat transfer plate 20a and surrounds the surface of the heat transfer plate, a semisolid heat conductive material 21a that contacts the exposed surface of the heat transfer plate 20a and is arranged to cover the molded resin 24 on one surface, and a heat dissipation member 26 that dissipates heat from the semiconductor module 1 via the heat conductive material 21a are assembled to the semiconductor module 1. Thus, a power conversion device 100 that can achieve cost reduction, improved productivity, and improved reliability can be manufactured.

[0046] In addition, the present invention is not limited to the above-mentioned embodiments, and various modifications or other configurations can be combined within the scope of the gist thereof. In addition, the present invention is not limited to a configuration having all the configurations described in the above-mentioned embodiments, and also includes a configuration in which a part of the configuration is deleted. Explanation of symbols

[0047] 1 Circuit body (semiconductor module) 2 Capacitors 3 Positive wiring 4 Negative wiring 5 Through holes 6 Wiring substrate 6a Centerline 7 Output Wiring 8 signal terminals 9Signal wiring 10 Capacitor positive terminal 11 Capacitor negative terminal 12-lead terminal 13 Wire bonding 20 heat transfer plate (lead frame) 20a1st heat transfer plate 20b 2nd heat transfer plate 21 Thermally Conductive Material (TIM) 21a 1st heat conducting material 21b Second heat conductive material 21c 3rd heat conduction material 22 Insulation sheet 23Semiconductor components (chips) 24 Molding resin (molding resin) 24a Step portion (convex portion) 24b Overmolding 25 heat sink 26 Cooling water circuit (heat dissipation component) 26a 1st cooling water circuit 26b Second cooling water circuit 27Laser opening machine 28 Mould 28a Gap between die and lead frame 100 Power conversion device a1 has the width of the upper surface of the step portion in the direction of the lead terminal b1 Width of the upper surface of the step portion in the direction without the lead terminal c1 The distance that the second heat dissipating member protrudes in the direction having the lead terminal d1 is the distance that the second heat dissipating member protrudes in the direction where there is no lead terminal.

Claims

1. A power conversion device, characterized in that: have: Semiconductor components; a heat transfer plate connected to the semiconductor element; A semiconductor module formed by molding the semiconductor element and the heat transfer plate with resin; a semisolid heat conductive material in contact with the heat transfer plate and arranged to cover one surface of the semiconductor module; as well as A heat dissipation member that dissipates heat from the semiconductor module via the heat conductive material.

2. The power conversion device according to claim 1, characterized in that: The semiconductor module has a step portion formed so as to surround a part of the heat conductive material on the one surface in contact with the semi-solid heat conductive material.

3. The power conversion device according to claim 2, characterized in that: The heat conductive material includes: a first heat conductive material disposed so as to be surrounded by the step portion; and a second heat conductive material in contact with the first heat conductive material and having a larger area than the first heat conductive material.

4. The power conversion device according to claim 3, characterized in that: The first heat conductive material and the second heat conductive material are integrally arranged on the one surface of the semiconductor module.

5. The power conversion device according to claim 1, characterized in that: One surface of the semiconductor module is exposed to the surface of the heat conductive material, and the other surface of the semiconductor module is in contact with a third heat conductive material different from the heat conductive material. The third heat conductive material is in contact with a second heat dissipating member different from the heat dissipating member on a surface opposite to a surface in contact with the semiconductor module.

6. A method for manufacturing a power conversion device, characterized in that: The semiconductor module is formed by molding the heat transfer plate connected to the semiconductor element with resin. A portion of the mold resin on one surface of the formed semiconductor module is removed to form a step portion that exposes the surface of the heat transfer plate and surrounds the surface of the heat transfer plate. A semisolid heat-conductive material and a heat-dissipating member are assembled into the semiconductor module. The semisolid heat-conductive material contacts the exposed surface of the heat transfer plate and is arranged so as to cover the molded resin on the one surface. The heat-dissipating member dissipates heat from the semiconductor module via the heat-conductive material.

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