Power converter, method for manufacturing a power converter

Abstract

This electric power conversion device is provided with: a semiconductor element; a heat transfer plate which is connected to the semiconductor element; a semiconductor module which is obtained by molding the semiconductor element and the heat transfer plate by means of a resin; a semi-solid heat conductive material which is arranged so as to be in contact with the heat transfer plate and so as to cover one surface of the semiconductor module; and a heat dissipation member which dissipates the heat of the semiconductor module through the heat conductive material.

Description

Technical Field

[0001] The present invention relates to a power conversion device and a method conversion device manufacturing method.

Background Art

[0002] In a power conversion device having a double-sided cooling structure, a heat conductive material such as TIM (Thermal Interface Material) is disposed between the device and a cooling water channel that is a heat dissipation member. However, the reliability of the device may decrease depending on the contact situation between this heat conductive material and the lead frame (heat transfer plate) provided in the semiconductor module. In addition, cost reduction and productivity improvement are also required for the power conversion device.

[0003] Patent Document disclosed below discloses a device having a structure in which a heat transfer layer is provided on the upper surface of a semiconductor element to efficiently dissipate heat generated in the semiconductor element to the outside.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the structure described in Patent Document 1, there is a possibility that TIM, which is a heat transfer layer (heat conductive material), may be pumped out, resulting in problems such as an increase in thermal resistance and a decrease in insulation. In view of this, an object of the present invention is to provide a power conversion device and a method for manufacturing the power conversion device that achieve cost reduction, productivity improvement, and reliability improvement.

Means for Solving the Problems

[0006] ​The power converter 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 resin, a semi-solid thermal conductive material that contacts the heat transfer plate and covers one side of the semiconductor module, and a heat dissipation member that dissipates heat from the semiconductor module via the thermal conductive material. The semiconductor module has a stepped portion formed on one surface that contacts the semi-solid thermal conductive material, such that it surrounds a portion of the thermal conductive material, and the thermal conductive material comprises a first thermal conductive material arranged so as to be surrounded by the stepped portion, and a second thermal conductive material that contacts the first thermal conductive material and has a larger area than the first thermal conductive material. . Furthermore, as a method for manufacturing a power converter, a semiconductor module is formed by molding a heat transfer plate connected to a semiconductor element with resin, and a portion of the molding resin on one side of the formed semiconductor module is removed to expose the surface of the heat transfer plate and to form a stepped portion that surrounds the surface of the heat transfer plate, which contacts the exposed surface of the heat transfer plate, and The semiconductor module So that it covers one of the aforementioned surfaces A semi-solid thermal conductive material is provided, comprising a first thermal conductive material positioned so as to surround the stepped portion, and a second thermal conductive material that is in contact with the first thermal conductive material and has a larger surface area than the first thermal conductive material. A heat dissipation member that dissipates heat from the semiconductor module via the heat conductive material is assembled to the semiconductor module. Manufacturing of power conversion equipment We will adopt this method. [Effects of the Invention]

[0007] We can provide a power converter and a method for manufacturing a power converter that achieve cost reduction, increased productivity, and improved reliability. [Brief explanation of the drawing]

[0008] [Figure 1] Circuit diagram of a power converter [Figure 2] Overall diagram of the power conversion device [Figure 3] Cross-sectional view of a power converter according to one embodiment of the present invention. [Figure 4] Diagram illustrating the first method of manufacturing a power converter. [Figure 5] Diagram illustrating the second method of manufacturing a power converter. [Figure 6] Diagram illustrating the positional relationship between the first thermal conductive material and the semiconductor module. [Figure 7] Diagram illustrating the positional relationship between the second thermal conductive material and the semiconductor module.

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

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

[0011] (One embodiment of the present invention and its overall configuration) (Figure 1) In the power converter 100, each of the multiple circuit bodies 1 constituting the power conversion circuit is composed of semiconductor elements such as IGBTs (Insulated Gate Bipolar Transistors) and MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). Two circuit bodies 1 and one capacitor 2 connected in series form a pair, each constituting a power conversion circuit for one phase. The three-phase power conversion circuits are connected to positive terminal wiring 3 and negative terminal wiring 4, respectively.

[0012] The circuit body 1 (semiconductor module 1) has three terminals: a high-voltage terminal for the main circuit (collector terminal for IGBTs, drain terminal for MOSFETs), a low-voltage terminal for the main circuit (emitter terminal for IGBTs, source terminal for MOSFETs), 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 board 6 (hereinafter referred to as the board 6) that is electrically connected to the circuit bodies 1 and in which a plurality of positive electrode wirings 3 and negative electrode wirings 4 are laminated on each other in the thickness direction, and a plurality of smoothing capacitors 2 provided corresponding to the plurality of circuit bodies 1 respectively. The positive electrode wiring 3 and the negative electrode wiring 4 are laminated on each other in the thickness direction of the board 6 (the front - back direction of the paper surface in FIG. 2), and connect the capacitor 2 and the circuit body 1 of each phase (details will be described later in FIGS. 4 to 7).

[0014] FIG. 2 shows a configuration example in which four circuit bodies 1 are arranged in parallel, and eight circuit bodies 1 are used as a one - phase circuit by arranging them to face each other with the positive electrode wiring 3 and the negative electrode wiring 4 interposed therebetween, and three phases are provided on the board 6. Thus, the circuit bodies 1 may be arranged in a multi - parallel connection according to the desired output current value. Similarly, the capacitors 2 may be connected in multi - parallel to the board 6 in order to satisfy the capacitor capacitance determined according to the desired input voltage fluctuation amount.

[0015] The board 6 has a plurality of conductor layers in the thickness direction, and each conductor layer is laminated via a resin layer. On the conductor layer of the board 6, a positive electrode wiring 3, a negative electrode wiring 4, an output wiring 7, and a signal wiring 9 are formed. The circuit bodies 1 and the capacitors 2 are connected to the positive electrode wiring 3 and the negative electrode wiring 4 by a bonding material such as solder. The circuit body 1 has a signal terminal 8 for connecting to the signal wiring 9. The positive electrode wiring 3, the negative electrode 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 configuration corresponding to the fact that the current supplied to the load at the connection destination is a larger current than other wirings.

[0016] The positive electrode wiring 3 and the negative electrode wiring 4 have through vias 5 (hereinafter referred to as vias 5). The vias 5 are provided in regions where the positive electrode wiring 3 and the negative electrode wiring 4 of each phase are not laminated on each other. When a plurality of positive electrode wirings 3 or negative electrode wirings 4 penetrate in the thickness direction of the substrate 6 and the vias 5 are formed, wirings of the same potential are electrically connected to each other. Thereby, the region where the vias 5 are not provided suppresses a decrease in the cross-sectional area of the positive electrode wiring 3 and the negative electrode wiring 4, and the region where the vias 5 are provided suppresses the positive electrode wiring 3 and the negative electrode wiring 4 from being disconnected.

[0017] When blind vias are used for the vias 5, by setting the first and second layers as the positive electrode wiring 3 and the third and fourth layers as the negative electrode wiring 4 from the upper surface of the substrate 6 formed in four layers (the surface in front of FIG. 2), the positive electrode wiring 3 and the negative electrode wiring 4 can be laminated without reducing the cross-sectional areas of the positive electrode wiring 3 and the negative electrode wiring 4.

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

[0019] The capacitors 2 are connected side by side along the substrate 6 in order to satisfy a capacitor capacitance determined according to a desired input voltage fluctuation amount, and also have positive electrode terminals 10 and negative electrode terminals 11 as terminals for connecting to the positive electrode wiring 3 and the negative electrode wiring 4 of the substrate 6.

[0020] The positive terminal 10 of capacitor 2 is connected to the positive wire 3, thereby electrically connecting it to the high-voltage terminal of the main circuit of the circuit body 1 on the high-side (upper arm) side. The positive wire 3 is also connected to the positive terminal 10 of the capacitor 2 of the other phase and to the high-voltage terminal of the main circuit of the circuit body 1 on the high-side of the other phase. The negative terminal 11 of capacitor 2 is connected to the negative wire 4, thereby connecting it to the low-voltage terminal of the main circuit of the circuit body 1 on the low-side (lower arm) side. The negative wire 4 is also connected to the negative terminal 11 of the capacitor 2 of the other phase and to the low-voltage terminal 12 of the main circuit of the circuit body 1 on the low-side of the other phase. The low-voltage terminal of the main circuit of the circuit body 1 on the high-side side is connected to the high-voltage terminal of the main circuit of the circuit body 1 on the low-side side by the output wires 7 of each phase. The output wires 7 of each phase are connected to loads such as motors, which are not shown in the diagram.

[0021] The control terminals of circuit body 1 are connected to a control circuit (not shown) and are switched on or off based on signals input from a higher-level control device such as a microcontroller, thereby outputting an AC voltage to a load such as a motor.

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

[0023] The lead terminals 12 protruding from the heat transfer plate 20 are connected to the circuit board 6 by solder. The heat transfer plate 20 is divided into two parts: the upper heat transfer plate 20 (source side) in Figure 3 is designated as the first heat transfer plate 20a, and the lower heat transfer plate 20 is designated as the second heat transfer plate 20b.

[0024] Two thermal conductive materials 21a and 21b are arranged on the upper surface of the first heat transfer plate 20a. The thermal conductive materials 21a and 21b are, for example, TIM. The thermal conductive materials 21a and 21b are semi-solid thermal conductive materials that are in contact with the first heat transfer plate 20a and are arranged to cover one side of the semiconductor module 1. A semi-solid thermal conductive material refers to a thermal conductive material composed of materials such as fillers or grease that deforms when pressed.

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

[0026] Furthermore, the semiconductor module 1 has a stepped portion 24a formed on one surface (upper surface) that contacts the thermal conductive materials 21a and 21b, surrounding the first thermal conductive material 21a. The stepped portion 24a is formed by processing a part of the mold resin 24 at the upper end of the semiconductor module 1. The stepped portion 24a has two convex shapes in the cross-sectional view of Figure 3. Of the thermal conductive materials 21a and 21b, the first thermal conductive material 21a is positioned on the inside of the stepped portion 24a so that it is surrounded by the stepped portion 24a. On the other hand, the second thermal conductive material 21b has a larger area than the first thermal conductive material 21a. When forming the convex portion of the stepped portion 24a by mold release from the viewpoint of mold release, it is desirable that the draft angle of the mold be 3 degrees or more.

[0027] The height of the semiconductor module 1, including the heat transfer plate 20 to which the semiconductor element chip 23 is soldered, varied within a range of less than 100 μm during prototyping and testing. Therefore, from the viewpoint of thermal resistance and material cost, it is desirable that the thickness of the first thermal conductive material 21a be 100 μm or less. Furthermore, from the viewpoint of pump-out, the thinner the second thermal conductive material 21b, the lower the thermal resistance, but at the same time it is necessary to absorb the variation in the height of the upper surface of the stepped portion 24a of the semiconductor module 1 mounted on the substrate 6. For this reason, it is desirable that the thickness of the second thermal conductive material 21b be 100 μm or less.

[0028] The semiconductor module 1 is in contact with the third thermal conductive material 21c via a heat transfer plate 20b on the surface below the substrate 6 (lower side in Figure 3). The substrate 6 is in contact with the heat dissipation sheet 25 on the lower side in Figure 3. The heat dissipation sheet 25 is in contact with the second cooling water channel 26b on the surface opposite to the surface in contact with the substrate 6. Due to this structure, both sides of the semiconductor module 1 are covered with thermal conductive materials 21a, 21b, and 21c, and the heat generated from the semiconductor module 1 and the substrate 6 is dissipated by the cooling water channels 26a and 26b, which are positioned to sandwich the semiconductor module 1 from both sides.

[0029] The two thermal conductive materials, the first thermal conductive material 21a and the second thermal conductive material 21b, may be integrated into a single thermal conductive material 21 and placed on one side of the semiconductor module 1.

[0030] (First method for manufacturing a power converter) (Figure 4) Figure 4(a) shows an example of the first manufacturing method, and Figure 4(b) shows the mold in Figure 4(a) after resin mold has been poured in and cured. The semiconductor element 23 is soldered to the first heat transfer plate 20a, and wire bonding 13 is applied to the semiconductor element 23 and the lead terminal 12. Furthermore, a semi-solid first thermal conductive material 21a is placed 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. After setting the heat transfer plates 20a, 20b, semiconductor element 23 and first thermal conductive material 21a in the mold 28 as described above, transfer molding is performed with resin 24. This makes it possible to form a semiconductor module 1 which has a stepped portion 24a on one side and the surface of the first heat transfer plate 20a is exposed.

[0031] In this way, by setting the first heat conductive material 21a in place in the mold 28 before resin molding, no gap is created between the first heat transfer plate 20a and the mold 28, preventing overmolding that increases thermal resistance. Furthermore, the grinding and cleaning processes that are performed to eliminate overmolding that occurs when the first heat conductive material 21a is not placed before resin molding are simplified. In addition, metal fragments and residues remain after cleaning, preventing a decrease in insulation performance and peeling of the first heat conductive material 21a. Thus, with the manufacturing method of the present invention, a semiconductor module 1 can be provided in which one electrode surface of the heat transfer plate 20 is exposed at the stage when resin molding is completed.

[0032] The semiconductor module 1 manufactured by this method is mounted on a substrate 6. A second thermal conductive material 21b is then brought into contact with the upper surface (one side) of the semiconductor module 1, and a third thermal conductive material 21c is brought into contact with the lower surface (the other side). Insulating sheets 22 are attached to each, and finally, the module is sandwiched from above and below by cooling water channels 26a and 26b. This completes the power conversion device 100.

[0033] Conventionally, when a semiconductor module 1 without a stepped portion 24a was produced after resin molding, problems arose such as increased thermal resistance due to pump-out or void formation. However, by assembling the semiconductor module 1 using the manufacturing method of the present invention, the first thermal conductive material 21a is sandwiched in the stepped portion 24a and the second thermal conductive material 21b is placed on its upper surface, thereby suppressing the pump-out of the second thermal conductive material 21b.

[0034] (Second method of manufacturing a power converter) (Figure 5) Figures 5(a) to 5(c) illustrate the second manufacturing method. First, in Figure 5(a), the semiconductor element 23 connected to the first heat transfer plate 20a and the second heat transfer plate 20b, and the lead terminal 12 are mounted on the mold 28. At this time, a gap 28a is created between the heat transfer plate 20a and the mold 28 due to variations in solder thickness and the tilt of the first heat transfer plate 20a.

[0035] Next, in Figure 5(b), resin 24 is poured into the mold 28 to perform transfer molding. As a result, resin flows into the gap 28a above the first heat transfer plate 20a shown in Figure 5(a), creating a semiconductor module 1 with an overmolded portion 24b. Then, in Figure 5(c), a portion of the molded resin 24 on one side of the semiconductor module 1, specifically the overmolded resin 24b on the upper side of the heat transfer plate 20a, is removed, for example, by a laser decapper 27. By performing this process, a stepped portion 24a is formed to surround the heat transfer plate 20a, providing a semiconductor module 1 in which one electrode surface of the heat transfer plate 20a is exposed.

[0036] A semi-solid thermal conductive material 21a, 21b is arranged to contact the exposed surface of the heat transfer plate 20a of the semiconductor module 1 and cover the mold resin 24 on one side. Cooling water channels 26a, 26b, which are heat dissipation members that dissipate heat from the semiconductor module 1 via the thermal conductive materials 21a, 21b, are then assembled to the semiconductor module 1 manufactured as described above. In this way, 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 for the relationship between the stepped portion 24a and the first heat conductive material 21a. Let the widths of the stepped portion 24a in the direction where the lead terminal 12 is present be a1 and a2 from the left in FIG. 6, and the widths of the stepped portion 24a in the direction where the lead terminal 12 is not present be b1 and b2 from the top in FIG. 6. At this time, a1 > b1 or a1 > b2. Also, a2 > b1 or a2 > b2. As a result, conventionally, there has been a problem that the second heat conductive material 21b has a decrease in insulation due to a part of the pumped-out heat conductive material 21 falling between the lead terminals 12. However, according to the present invention, it becomes difficult to pump out the heat conductive material 21, and the resistance of the cooling water channel 26 increases. Further, even if the heat conductive material 21b is pumped out and falls downward, it will preferentially fall in the direction where there is no lead terminal 12, so the insulation will not decrease.

[0038] (Figure 7) Regarding the second heat conductive material 21b that contacts the upper surface of the semiconductor module 1, the following relationship holds for the length of the second heat conductive material 21b that protrudes from the stepped portion 24a of the semiconductor module 1. Let the distances by which the second heat conductive material 21b protrudes from the stepped portion 24a in the direction where the lead terminal 12 is present be c1 and c2 from the left in FIG. 7, and the distances by which the second heat conductive material 21b protrudes from the stepped portion 24a in the direction where the lead terminal 12 is not present be d1 and d2 from the top in FIG. 7. At this time, 0 < c1 < d1 or 0 < c1 < d2. Also, 0 < c2 < d1 or 0 < c2 < d2. As a result, even if the second heat conductive material 21b is pumped out and falls downward, it will preferentially fall in the direction where there is no lead terminal 12, so the insulation of the lead terminal 12 will not decrease.

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

[0040] (1) The power converter 100 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 resin 24, semi-solid thermal conductive materials 21a and 21b that are in contact with the heat transfer plates 20a and 20b and are arranged to cover one side of the semiconductor module 1, and a heat dissipation member 26 that dissipates heat from the semiconductor module via the thermal conductive materials 21a and 21b. In this way, a power converter 100 can be provided that achieves cost reduction, improved productivity, and improved reliability.

[0041] (2) The semiconductor module 1 has a stepped portion 24a formed on one surface that is in contact with the semi-solid thermal conductive materials 21a and 21b, surrounding a portion of the thermal conductive materials 21a and 21b (the first thermal conductive material 21a). This suppresses pump-out and provides a semiconductor module 1 in which one electrode surface of the heat transfer plate 20a is exposed.

[0042] (3) The thermal conductive material 21 comprises a first thermal conductive material 21a arranged so as to be surrounded by the stepped portion 24a, and a second thermal conductive material 21b that is in contact with the first thermal conductive material 21a and has a larger surface area than the first thermal conductive material 21a. In this manner, both sides of the semiconductor module 1 are covered by the thermal 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 arranged to sandwich the semiconductor module 1 from both sides.

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

[0044] (5) One side of the semiconductor module 1 has the surface of the thermal conductive material 21a exposed, and the other side of the semiconductor module 1 is in contact with a third thermal conductive material 21c different from the thermal conductive material 21a, and the third thermal conductive material 21c is in contact with a second heat dissipation member 26b different from the heat dissipation member 26a on the side opposite to the side in contact with the semiconductor module 1. In this way, a power conversion device 100 can be provided in which the semiconductor module 1 is cooled on both sides.

[0045] (6) As a method for manufacturing the power converter 100 of the present invention, a semiconductor module 1 is formed by molding heat transfer plates 20a and 20b connected to a semiconductor element 23 with resin 24, a portion of the molded resin 24 on one side of the formed semiconductor module 1 is removed to expose the surface of the heat transfer plate 20a, and a stepped portion is formed to surround the surface of the heat transfer plate, and a semi-solid thermal conductive material 21a is placed in contact with the exposed surface of the heat transfer plate 20a and to cover the molded resin 24 on one side, and a heat dissipation member 26 dissipates heat from the semiconductor module 1 via the thermal conductive material 21a is assembled to the semiconductor module 1. In this way, a power converter 100 can be manufactured that achieves cost reduction, improved productivity, and improved reliability.

[0046] It should be noted that the present invention is not limited to the embodiments described above, and various modifications and combinations of other configurations can be made without departing from the spirit of the invention. Furthermore, the present invention is not limited to having all the configurations described in the embodiments described above, and may also include configurations in which some of those configurations are omitted. [Explanation of symbols]

[0047] 1. Circuit unit (semiconductor module) 2 Capacitors 3. Positive Wiring 4. Negative wiring 5 Beers 6 Wiring board 6a center line 7 Output Wiring 8 signal terminals 9. Signal Wiring 10 Capacitor positive terminal 11 Capacitor negative terminal 12 Lead terminals 13. Wire bonding 20 Heat transfer plates (lead frames) 20a First heat transfer plate 20b Second heat transfer plate 21 Thermal Insulators (TIM) 21a First thermal conductive material 21b Second thermal conductive material 21c Third thermal conductive material 22 Insulating Sheet 23. Semiconductor devices (chips) 24. Mold resin 24a Stepped section (protruding section) 24b Overmolding 25 Heat dissipation sheets 26 Cooling water channel (heat dissipation component) 26a 1st cooling channel 26b 2nd cooling channel 27 Laser Decapper 28 molds 28a Gap between the mold and the lead frame 100 Power converter a1 Width of the upper surface of the stepped portion in the direction of the lead terminals b1 Width of the upper surface of the stepped portion in the direction without lead terminals c1 Distance the second heat dissipation component extends in the direction of the lead terminal. d1: The distance the second heat dissipation component extends in the direction without lead terminals.

Claims

1. Semiconductor elements and A heat transfer plate connected to the aforementioned semiconductor element, A semiconductor module formed by molding the semiconductor element and the heat transfer plate with resin, A semi-solid thermal conductive material is arranged to contact the heat transfer plate and cover one side of the semiconductor module, A heat dissipation member that dissipates heat from the semiconductor module via the heat conductive material, Equipped with, The semiconductor module has a stepped portion formed on one surface that contacts the semi-solid thermal conductive material, such that it surrounds a portion of the thermal conductive material. The thermal conductive material comprises a first thermal conductive material arranged so as to surround the stepped portion, and a second thermal conductive material that is in contact with the first thermal conductive material and has a larger surface area than the first thermal conductive material. Equipped with Power converter.

2. A power conversion device according to claim 1, The first thermal conductive material and the second thermal conductive material are integrated and arranged on one side of the semiconductor module. Power converter.

3. A semiconductor module is formed by molding a heat transfer plate, which connects to the semiconductor element, with resin. By removing a portion of the mold resin on one side of the formed semiconductor module, the surface of the heat transfer plate is exposed, and a stepped portion is formed to surround the surface of the heat transfer plate. A semi-solid thermal conductive material is provided, comprising: a first thermal conductive material that contacts the exposed surface of the heat transfer plate and is arranged so as to cover one of the semiconductor modules, with its periphery surrounded by the stepped portion; and a second thermal conductive material that contacts the first thermal conductive material and has a larger surface area than the first thermal conductive material. A heat dissipation member that dissipates heat from the semiconductor module via the heat conductive material is assembled to the semiconductor module. A method for manufacturing a power conversion device.

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