Semiconductor device, method for manufacturing semiconductor device, and electric power conversion device

Abstract

A semiconductor device (100a) comprises a semiconductor element (1a), a main electrode-side terminal (4a), and a metal plate (5). The semiconductor element (1a) has a main electrode (2a) and a control electrode (3). The main electrode-side terminal (4a) is connected to the main electrode (2a). The metal plate (5) is connected to the control electrode (3).

Description

Semiconductor device, semiconductor device manufacturing method, and power conversion device

[0001] The present disclosure relates to a semiconductor device, a method for manufacturing a semiconductor device, and a power conversion device.

[0002] Conventionally, semiconductor devices have been known in which DLB (Direct Lead Bonding) connection is used on the main electrode side of a semiconductor element and wire connection is used on the control electrode side (see, for example, Japanese Patent Application Laid-Open No. 2011-258594). In Japanese Patent Application Laid-Open No. 2011-258594, the main electrode of the semiconductor element is directly connected to a terminal, and the control electrode is connected to the terminal via a wire.

[0003] JP 2011-258594 A

[0004] However, in the semiconductor device described above, problems arise due to wire connection. Specifically, wire connection can cause problems such as wire breakage due to thermal fatigue, the complication of the manufacturing process when DLB connection is used on the main electrode side, and the generation of dead space due to the movement of the bonding tool. Thus, there is room for improvement in the reliability of the semiconductor device. Furthermore, when DLB connection is used on the control electrode, high positional accuracy is required on the control electrode side.

[0005] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a semiconductor device in which the control electrode and the control electrode side terminal are easily connected and which has improved reliability.

[0006] A semiconductor device according to the present disclosure includes a semiconductor element, a main electrode side terminal, and a metal plate. The semiconductor element has a main electrode and a control electrode. The main electrode side terminal is connected to the main electrode. The metal plate is connected to the control electrode.

[0007] A power conversion device according to the present disclosure includes a main conversion circuit and a control circuit. The main conversion circuit has the semiconductor device described above and converts input power to output the converted power. The control circuit outputs a control signal to the main conversion circuit to control the main conversion circuit.

[0008] A method for manufacturing a semiconductor device according to the present disclosure includes the steps of preparing a semiconductor element having a plurality of control electrodes, a plurality of control electrode side terminals, and a metal plate assembly, connecting the metal plate assembly to the control electrodes and the control electrode side terminals, and cutting the metal plate assembly.

[0009] A method for manufacturing a semiconductor device according to the present disclosure includes the steps of: preparing a semiconductor element having a plurality of control electrodes, a plurality of control electrode terminals, and a plurality of metal plates; and connecting the metal plates to the control electrodes and the control electrode terminals. The plurality of metal plates are connected to each other by adhesive portions.

[0010] According to the above, the control electrode and the control electrode side terminal can be easily connected, and a semiconductor device with improved reliability can be obtained.

[0011] 8 is a schematic plan view of a semiconductor device according to a first embodiment. FIG. 9 is a schematic cross-sectional view of the semiconductor device taken along line II-II in FIG. 1 . FIG. 10 is a schematic partial cross-sectional view of a metal plate and a control electrode-side terminal of a first modified example of the semiconductor device according to the first embodiment. FIG. 11 is a schematic partial cross-sectional view of a metal plate and a control electrode-side terminal of a second modified example of the semiconductor device according to the first embodiment. FIG. 12 is a schematic partial cross-sectional view of a metal plate and a control electrode-side terminal of a third modified example of the semiconductor device according to the first embodiment. FIG. 13 is a schematic partial cross-sectional view of a metal plate and a control electrode-side terminal of a fourth modified example of the semiconductor device according to the first embodiment. FIG. 14 is a schematic partial cross-sectional view of a metal plate and a control electrode-side terminal of a fifth modified example of the semiconductor device according to the first embodiment. FIG. 15 is a schematic partial plan view of a control electrode and a metal plate of a sixth modified example of the semiconductor device according to the first embodiment. FIG. 16 is a schematic partial cross-sectional view of a semiconductor device according to the first embodiment. 19 is a schematic partial plan view of a semiconductor device according to a second embodiment. 20 is a schematic plan view of a semiconductor device according to a third embodiment. 21 is a schematic cross-sectional view of a semiconductor device taken along line XVIII-XVIII in Fig. 17. 22 is a schematic plan view of a semiconductor device according to a fourth embodiment. 23 is a schematic cross-sectional view of a semiconductor device taken along line XX-XX in Fig. 19. 24 is a block diagram showing the configuration of a power conversion system to which a power conversion device according to a fifth embodiment is applied.

[0012] Hereinafter, embodiments of the present disclosure will be described. Unless otherwise specified, the same or corresponding parts in the following drawings will be denoted by the same reference numerals, and the description thereof will not be repeated.

[0013] First Embodiment <Configuration of Semiconductor Device> Fig. 1 is a schematic plan view of a semiconductor device 100a according to a first embodiment. Fig. 2 is a schematic cross-sectional view of the semiconductor device 100a taken along line II-II in Fig. 1.

[0014] 1 is, for example, a power semiconductor device 100a, and mainly includes a semiconductor element 1, a main electrode side terminal 4a, four control electrode side terminals 4b, a heat sink side terminal 4c, four metal plates 5, a joint 7, a heat sink 8, an insulating sheet 9a, a metal foil 9b, and a sealing resin 6. Note that the rectangular dotted line in FIG. 1 indicates the outline of the sealing resin 6.

[0015] The joints 7 include first joints 71a and 71b, a second joint 72, a third joint 73, fourth joints 74a and 74b, and a fifth joint (not shown).

[0016] 1 and 2, the direction perpendicular to the first heat sink surface 81s is defined as the z direction. As will be described later, the first heat sink surface 81s is the surface of the heat sink 8 on which the semiconductor element 1 is mounted. As shown in FIG. 1, in a plan view seen from the z direction, the direction in which the main electrode side terminals 4a and the control electrode side terminals 4b extend is defined as the x direction. The direction perpendicular to the x direction and the z direction is defined as the y direction. From a different perspective, the direction perpendicular to the direction in which the metal plate 5 extends toward the control electrode side terminal 4b is defined as the y direction.

[0017] The semiconductor element 1 includes a semiconductor element 1a and a semiconductor element 1b. The number of semiconductor elements 1 does not have to be limited to two. The number of semiconductor elements 1 may be one, or three or more. The semiconductor element 1a has a main electrode 2a and a plurality of control electrodes 3. Specifically, the main electrode 2a and four control electrodes 3 are formed on the surface of the semiconductor element 1a. The semiconductor element 1b has a main electrode 2b. No control electrode 3 is formed on the surface of the semiconductor element 1b.

[0018] 2, the semiconductor elements 1a and 1b are mounted on a first heat sink surface 81s. On the first heat sink surface 81s, the semiconductor elements 1a and 1b are spaced apart from each other in the x direction.

[0019] 1 and 2, the main electrodes 2a and 2b are connected to a common terminal. Specifically, the main electrode 2a is connected to the main electrode terminal 4a via a first joint 71a. The main electrode 2b is connected to the main electrode terminal 4a via a first joint 71b. The main electrodes 2a and 2b may be connected to different terminals.

[0020] On the surface of the semiconductor element 1a, the four control electrodes 3 are arranged spaced apart from one another in the y direction. The number of control electrodes 3 is not limited to four. The number of control electrodes 3 may be one, two, five or more.

[0021] The control electrode 3 is connected to the control electrode side terminal 4b via the metal plate 5. Specifically, the metal plate 5 has one end 5a and the other end 5b. The one end 5a of the metal plate 5 is connected to the control electrode 3 via a second joint 72. The other end 5b of the metal plate 5 is connected to the control electrode side terminal 4b via a third joint 73. As shown in FIG. 1 , the metal plate 5 extends in the x direction. The other end 5b is located on the opposite side of the one end 5a in the x direction.

[0022] The heat sink 8 has a first heat sink surface 81s and a second heat sink surface 82s. The first heat sink surface 81s is the surface on which the semiconductor element 1 is mounted. The second heat sink surface 82s is the surface located on the opposite side of the first heat sink surface 81s. The heat sink 8 is connected to the semiconductor element 1a via the fourth joint portion 74a. The heat sink 8 is connected to the semiconductor element 1b via the fourth joint portion 74b.

[0023] 1, the heat sink side terminal 4c is connected to the first heat sink surface 81s of the heat sink 8 via a fifth joint (not shown). On the first heat sink surface 81s, the heat sink side terminal 4c is spaced apart in the y direction from the control electrode side terminal 4b. As shown in FIGS. 1 and 2, the heat sink side terminal 4c extends in the x direction.

[0024] 2, a metal foil 9b is connected to the second heat sink surface 82s via an insulating sheet 9a. The surface of the metal foil 9b opposite to the surface connected to the insulating sheet 9a is exposed from the sealing resin 6.

[0025] The sealing resin 6 covers the semiconductor element 1, a portion of the main electrode side terminal 4a, a portion of the control electrode side terminal 4b, a portion of the heat sink side terminal 4c, the metal plate 5, the heat sink 8, and the insulating sheet 9a. This improves the insulation of the semiconductor device 100a and reduces the effects of the external environment, such as humidity and contamination. The main electrode side terminal 4a extends from the semiconductor element 1 to the outside of the sealing resin 6. The control electrode side terminal 4b extends from the other end 5b of the metal plate 5 to the outside of the sealing resin 6. The heat sink side terminal 4c extends from the first heat sink surface 81s of the heat sink 8 to the outside of the sealing resin 6. As shown in FIG. 1 , the main electrode side terminal 4a, the control electrode side terminal 4b, and the heat sink side terminal 4c extend in the x direction. The control electrode side terminal 4b and the heat sink side terminal 4c extend in a direction opposite to the extension direction of the main electrode side terminal 4a.

[0026] To enable connection to an external device outside the sealing resin 6, a portion of each of the main electrode side terminal 4a, the control electrode side terminal 4b, and the heat sink side terminal 4c extends outward from the surface of the sealing resin 6. The portions of the main electrode side terminal 4a, the control electrode side terminal 4b, and the heat sink side terminal 4c extending outward from the sealing resin 6 may be bent, for example, by forming.

[0027] The semiconductor element 1 is a so-called power semiconductor element 1 that controls electric power. Materials constituting the semiconductor element 1 include silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga ２ O ３ ), or diamond may also be used.

[0028] The type of semiconductor element 1 is not particularly limited, but may be, for example, an insulated gate bipolar transistor (IGBT), a metal oxide semiconductor field effect transistor (MOSFET), a Schottky barrier diode, or the like.

[0029] Any material having excellent electrical and mechanical properties may be used to form the main electrodes 2 a, 2 b and the control electrode 3. The material may be, for example, any one selected from the group consisting of aluminum, copper, silver, nickel, and gold, or an alloy containing at least one of these elements.

[0030] The main electrode side terminal 4 a, the control electrode side terminal 4 b, and the heat sink side terminal 4 c may be made of any material having high conductivity, for example, a material containing at least one of copper and aluminum.

[0031] The material constituting the metal plate 5 may be any material having high electrical conductivity, and may include, for example, at least one of copper and aluminum.

[0032] The material constituting the heat sink 8 and the metal foil 9b may be any metal with excellent thermal conductivity. The material constituting the heat sink 8 and the metal foil 9b may be, for example, any one selected from the group consisting of aluminum, copper, iron, and nickel, or an alloy containing at least one of these. Specifically, the material constituting the heat sink 8 and the metal foil 9b may be, for example, an aluminum alloy, a copper alloy, an iron alloy, a nickel alloy, or a composite material containing a nickel alloy. In particular, when a semiconductor element 1 with a large current capacity is used, the material constituting the heat sink 8 and the metal foil 9b may be copper, which has excellent thermal conductivity.

[0033] The metal foil 9b and the heat sink 8 are electrically insulated by an insulating sheet 9a. The material constituting the insulating sheet 9a may be, for example, a resin insulating sheet containing inorganic powder or glass fiber. Examples of inorganic powder include alumina, beryllia, boron nitride, magnesia, silica, silicon nitride, and aluminum nitride. Examples of the resin (matrix resin) contained in the insulating sheet include epoxy resin, unsaturated polyester resin, phenolic resin, melamine resin, silicone resin, and polyimide resin. Epoxy resin is particularly preferred as the resin contained in the insulating sheet.

[0034] The material constituting the joint 7 is preferably a high-temperature solder containing lead and tin. The material constituting the joint 7 does not have to be solder. Specifically, the material constituting the joint 7 may be a conductive adhesive containing silver or copper nanoparticle paste, or a conductive adhesive containing epoxy resin and either silver or copper particles.

[0035] The material constituting the sealing resin 6 may be, for example, an epoxy resin filled with silica powder. The content of silica powder in the epoxy resin is selected optimally, for example, taking into consideration the thermal expansion coefficients of the components used in the semiconductor device 100a according to the first embodiment. The thermal expansion coefficient of copper is 17 ppm / °C. Therefore, for example, when the main electrode side terminals 4a, the control electrode side terminals 4b, and the heat sink 8 are made of copper, the content of silica powder in the epoxy resin may be adjusted so that the thermal expansion coefficient of the sealing resin 6 is 17 ppm / °C. In this way, a semiconductor device 100a in which warping of the components used in the semiconductor device 100a is suppressed can be obtained.

[0036] In order to improve the heat dissipation property of the sealing resin 6, alumina powder may be used as a filler to be filled in the sealing resin 6 instead of silica powder.

[0037] The sealing resin 6 may be formed by transfer molding. When the sealing resin 6 is formed by transfer molding, a molding die is used. The molding die may be a die that can be separated into upper and lower halves. When the sealing resin 6 is formed by transfer molding, the upper and lower separated molding dies are arranged to sandwich the lead frame (terminals). After the sealing resin 6 is formed, each terminal protrudes from the side of the sealing resin 6.

[0038] 1 and 2, the semiconductor device 100a according to the first embodiment is characterized in that the main electrode side terminal 4a is connected to the main electrodes 2a and 2b, and the metal plate 5 is connected to the control electrode 3. The main electrodes 2a and 2b must have a large area so as to be able to handle large currents and high voltages. Therefore, DLB connection can be adopted on the main electrodes 2a and 2b side.

[0039] On the other hand, compared to the magnitude of the current and voltage flowing through the main electrodes 2 a and 2 b, the magnitude of the current and voltage required for the control electrode 3 need only be the current and voltage necessary for signal transmission. Therefore, the area required for the control electrode 3 is small. However, if the area of ​​the control electrode 3 is small, it becomes difficult to ensure the positional accuracy of the terminal when a DLB connection is adopted on the control electrode 3 side.

[0040] The positional accuracy required to connect the metal plate 5 to the control electrode 3 is lower than the positional accuracy required to directly connect a terminal to the control electrode 3. Therefore, in the semiconductor device 100a according to the first embodiment, the metal plate 5 is connected to the control electrode 3. This solves problems that arise from wire connection, such as wire breakage due to thermal fatigue of the wire, complication of the manufacturing process when DLB connection is used on the main electrode 2 side, and generation of dead space for moving the bonding tool, and also reduces the positional accuracy required on the control electrode 3 side.

[0041] 1, in a plan view of the first heat sink surface 81s, a portion of the control electrode side terminal 4b may overlap the first heat sink surface 81s. By connecting the control electrode 3 and the control electrode side terminal 4b via the metal plate 5 in this way, it is possible to reduce the dead space required for moving a joining tool caused by wire connection. As a result, it is possible to reduce the size of the semiconductor device 100a.

[0042] To ensure a large capacity in the main electrodes 2 a, 2 b, it is preferable to connect thick wiring (terminals) to the main electrodes 2 a, 2 b. However, in order to shorten the manufacturing process and reduce manufacturing costs, the main electrode side terminal 4 a, the control electrode side terminal 4 b, and the heat sink side terminal 4 c are each formed, for example, by punching out a single metal material using a die. Therefore, because each terminal is formed from a single metal material, the main electrode side terminal 4 a, the control electrode side terminal 4 b, and the heat sink side terminal 4 c have the same thickness, making it difficult to adjust the thickness of each.

[0043] 2 , the thickness of the metal plate 5 in the z direction may be smaller than the thicknesses of the main electrode side terminal 4 a, the control electrode side terminal 4 b, and the heat sink side terminal 4 c in the z direction. The main electrode side terminal 4 a, the control electrode side terminal 4 b, and the heat sink side terminal 4 c are preferably thicker to ensure their strength. On the other hand, the strength of the metal plate 5 may be equal to or smaller than the strength of the main electrode side terminal 4 a, the control electrode side terminal 4 b, and the heat sink side terminal 4 c.

[0044] Furthermore, the metal plate 5 is a constituent material independent of the main electrode side terminal 4a, the control electrode side terminal 4b, and the heat sink side terminal 4c. As described above, the control electrode 3 only needs to be able to carry the current and voltage necessary for signal transmission. Therefore, in order to reduce manufacturing costs, the metal plate 5 connected to the control electrode 3 may be thinner than the terminals. Using such a thin metal plate 5 improves the formability of the metal plate 5.

[0045] 3 to 7 are schematic partial cross-sectional views of the metal plate 5 and the control electrode side terminal 4b of Modifications 1 to 5 of the semiconductor device 100a according to Embodiment 1. The semiconductor device 100a shown in Figures 3 to 7 basically has the same configuration as the semiconductor device 100a shown in Figures 1 and 2 and can obtain the same effects, but the shapes of the metal plate 5 and the control electrode side terminal 4b are different.

[0046] The other end 5b of the metal plate 5 may be shaped to fit along the side and top surfaces of the control electrode terminal 4b. Also, the tip of the control electrode terminal 4b may be shaped to fit along the side and top surfaces of the metal plate 5.

[0047] As shown in FIG. 3 , in the metal plate 5 of the semiconductor device 100a according to the first embodiment, the metal plate 5 may have a first step portion 51 at the other end 5b. The first step portion 51 includes a first step surface 51s1 and a second step surface 51s2. The first step surface 51s1 is perpendicular to the x-direction. The second step surface 51s2 is perpendicular to the z-direction. The first step surface 51s1 is connected to the second step surface 51s2. The first step surface 51s1 and the second step surface 51s2 each face the control electrode-side terminal 4b. The metal plate 5 is connected to the control electrode-side terminal 4b at the first step portion 51 via a third joint portion 73. This configuration can prevent misalignment when connecting the metal plate 5 to the control electrode-side terminal 4b.

[0048] As shown in FIG. 4 , the control electrode side terminal 4b of the semiconductor device 100a according to the first embodiment in Modification 2 may have a second step portion 41. The second step portion 41 includes a first step surface 41s1 and a second step surface 41s2. The first step surface 41s1 is perpendicular to the z-direction. The second step surface 41s2 is perpendicular to the x-direction. The first step surface 41s1 is connected to the second step surface 41s2. The first step surface 41s1 and the second step surface 41s2 each face the metal plate 5. The control electrode side terminal 4b is connected to the metal plate 5 at the second step portion 41 via a third joint portion 73. This configuration can prevent misalignment when connecting the metal plate 5 to the control electrode side terminal 4b.

[0049] As shown in FIG. 5 , both the metal plate 5 and the control electrode-side terminal 4b of Modification 3 of the semiconductor device 100a according to Embodiment 1 may have a step portion. Specifically, the metal plate 5 may have a first step portion 51 at the other end 5b. The control electrode-side terminal 4b may have a second step portion 41. The first step portion 51 and the second step portion 41 may be fitted together so that the second step surface 51s2 of the first step portion 51 faces the first step surface 41s1 of the second step portion 41. The first step portion 51 and the second step portion 41 are connected via a third joint portion 73. This configuration can prevent misalignment when connecting the metal plate 5 and the control electrode-side terminal 4b.

[0050] 6 , in the metal plate 5 of the fourth modification of the semiconductor device 100a according to the first embodiment, a convex portion 52 may be formed at the other end 5b. A concave portion 42 may be formed in the control electrode side terminal 4b. The concave portion 42 may be a through hole that reaches from the upper surface to the lower surface of the control electrode side terminal 4b. The convex portion 52 can be inserted into the concave portion 42. In this way, it is possible to prevent misalignment when connecting the metal plate 5 and the control electrode side terminal 4b.

[0051] 7 , a convex portion 43 may be formed on the control electrode side terminal 4b of the semiconductor device 100a according to the fifth modification of the first embodiment. A concave portion 53 may be formed on the metal plate 5. The concave portion 53 may be a through hole that reaches from the upper surface to the lower surface of the metal plate 5. The convex portion 43 may be inserted into the concave portion 53. In this way, it is possible to prevent misalignment when connecting the metal plate 5 and the control electrode side terminal 4b.

[0052] FIG. 8 is a schematic partial plan view of the control electrode 3 and the metal plate 5 of a sixth variation of the semiconductor device 100a according to the first embodiment. FIG. 9 is a schematic partial cross-sectional view of the semiconductor device 100a taken along line IX-IX in FIG. 8. The semiconductor device 100a shown in FIGS. 8 and 9 basically has the same configuration as the semiconductor device 100a shown in FIGS. 1 and 2 and can achieve the same effects, but differs in that the side surface of the second joint 72 is fillet-shaped. As shown in FIG. 8, the area of ​​the metal plate 5 connected to the control electrode 3 via the second joint 72 need only be smaller than the area of ​​the control electrode 3.

[0053] Specifically, the control electrode 3 has a first joint interface 3s with the second joint portion 72. The metal plate 5 has a second joint interface 5s with the second joint portion 72. In a plan view of the first joint interface 3s, the outer periphery 3l of the first joint interface 3s is larger than the outer periphery 5l of the second joint interface 5s. In this way, when the second joint portion 72 is formed, a fillet is naturally formed on the side surface of the second joint portion 72. As a result, thermal stress applied to the thermal stress concentration points in the control electrode 3 and the second joint portion 72 is reduced, and resistance to thermal fatigue is improved.

[0054] <Method of Manufacturing Semiconductor Device> Figure 10 is a flowchart of a method of manufacturing a semiconductor device 100a according to the first embodiment. Figures 11 to 13 are schematic plan views showing a step of a method of manufacturing a semiconductor device 100a according to the first embodiment. The method of manufacturing the semiconductor device 100a according to the present embodiment first performs a step (S1a) of preparing a semiconductor element 1a having a plurality of control electrodes 3, a plurality of control electrode side terminals 4b, and a metal plate assembly 50. As shown in Figure 11, a plurality of control electrodes 3 are formed on the surface of the semiconductor element 1a. The control electrode side terminal 4b is arranged spaced apart from the control electrode 3. Meanwhile, the main electrodes 2a, 2b may be directly connected to the main electrode side terminal 4a.

[0055] Next, a step (S2a) of connecting the metal plate assembly 50 is performed. In this step (S2a), as shown in FIG. 12 , the metal plate assembly 50 is connected to the control electrode 3 and the control electrode-side terminal 4b. The metal plate assembly 50 has a plurality of metal plates 5 and a common portion 55. As shown in FIG. 12 , the plurality of metal plates 5 are integrally formed via the common portion 55. The metal plate assembly 50 thus integrally formed is connected to a plurality of control electrodes 3 via second joint portions 72. The metal plate assembly 50 is also connected to a plurality of control electrode-side terminals 4b via third joint portions 73.

[0056] Next, a cutting step (S3a) is performed. In this step (S3a), as shown in FIG. 13 , the multiple metal plates 5 that were connected to each other via the common portion 55 are cut away. Specifically, the metal plate assembly 50 is cut along the cutting line L shown in FIG. 12 . In this manner, the multiple metal plates 5 can be cut away from the common portion 55. As a result, the multiple metal plates 5 connect the control electrodes 3 and the control electrode-side terminals 4b independently of each other. In this manner, the metal plates 5 are positioned collectively, thereby shortening the manufacturing process of the semiconductor device 100a. Furthermore, compared to DLB connection, the positional accuracy required on the control electrode 3 side can be reduced.

[0057] <Modification of Semiconductor Device Manufacturing Method> Fig. 14 is a flowchart of a modification of the method for manufacturing the semiconductor device 100a according to embodiment 1. Fig. 15 is a schematic plan view showing one step of the modification of the method for manufacturing the semiconductor device 100a according to embodiment 1. Fig. 15 corresponds to Fig. 12.

[0058] The modified manufacturing method of the semiconductor device 100a according to the present embodiment is basically the same as the manufacturing method of the semiconductor device 100a shown in FIGS. 11 to 13, but differs in that the control electrode 3 and the control electrode side terminal 4b are connected using a plurality of metal plates 5 connected to each other by adhesive portions 56, as shown in FIG. 15.

[0059] In a modified example of the method for manufacturing semiconductor device 100a according to the present embodiment, first, a step (S1b) is performed of preparing semiconductor element 1a having a plurality of control electrodes 3, a plurality of control electrode-side terminals 4b, and a plurality of metal plates 5. This step (S1b) is basically the same as the preparation step (S1a) shown in FIG.

[0060] Next, a step (S2b) of connecting metal plates 5 is performed. In this step (S2b), as shown in FIG. 15 , metal plates 5 are connected to control electrodes 3 and control electrode-side terminals 4b. As described above, the plurality of metal plates 5 are connected to one another by adhesive portions 56. Adhesive portions 56 may be, for example, resin or adhesive tape. The plurality of metal plates 5 connected to one another by adhesive portions 56 in this manner are connected to the plurality of control electrodes 3 via second joint portions 72. The plurality of metal plates 5 are also connected to the plurality of control electrode-side terminals 4b via third joint portions 73.

[0061] When the adhesive portion 56 is made of resin, it is preferable to use a material for the adhesive portion 56 that has a thermal expansion behavior similar to that of the sealing resin 6. This can prevent peeling and cracking caused by thermal stress. Therefore, as will be described later, when sealing is performed using a case mold, it is preferable to use a potting resin for the sealing resin 6. On the other hand, when sealing is performed using a transfer mold, handling is difficult at room temperature or temperatures close to room temperature. Therefore, it is preferable to make the composition and particle size distribution of the filler in the sealing resin 6 as uniform as possible and to use a matrix resin with low viscosity.

[0062] If the adhesive portion 56 is made of resin, the process proceeds to the next step. On the other hand, if the adhesive portion 56 is made of adhesive tape, the adhesive tape is peeled off before the process proceeds to the next step.

[0063] In the modified manufacturing method of the semiconductor device 100a according to the present embodiment, the cutting step (S3a) is omitted because the plurality of metal plates 5 are not integrated by the common portion 55. As the next step, for example, a sealing step may be performed.

[0064] <Operation and Effect> The semiconductor device 100a according to the present disclosure includes a semiconductor element 1a, a main electrode side terminal 4a, and a metal plate 5. The semiconductor element 1a has a main electrode 2a and a control electrode 3. The main electrode side terminal 4a is connected to the main electrode 2a. The metal plate 5 is connected to the control electrode 3.

[0065] This solves problems that arise when connecting wires, such as wire breakage due to thermal fatigue, the complication of the manufacturing process when DLB connection is used on the main electrode 2 side, and the occurrence of dead space for moving the bonding tool, and also reduces the positional accuracy required on the control electrode 3 side. In other words, it is easy to connect the control electrode 3 and the control electrode-side terminal 4b, and a semiconductor device 100a with improved reliability can be obtained.

[0066] In the semiconductor device 100a, the main electrode 2a and the main electrode side terminal 4a are connected via a first joint 71a, and the control electrode 3 and the metal plate 5 are connected via a second joint 72.

[0067] This solves problems that arise when connecting wires, such as wire breakage due to thermal fatigue, the complication of the manufacturing process when DLB connection is used on the main electrode 2 side, and the occurrence of dead space for moving the bonding tool, and also reduces the positional accuracy required on the control electrode 3 side. In other words, it is easy to connect the control electrode 3 and the control electrode-side terminal 4b, and a semiconductor device 100a with improved reliability can be obtained.

[0068] The semiconductor device 100a further includes a control electrode terminal 4b. The metal plate 5 has one end 5a and the other end 5b. The one end 5a is connected to the control electrode 3. The other end 5b is located on the opposite side of the one end 5a. The control electrode terminal 4b is connected to the other end 5b via a third joint 73.

[0069] This solves problems that arise when connecting wires, such as wire breakage due to thermal fatigue, the complication of the manufacturing process when DLB connection is used on the main electrode 2 side, and the occurrence of dead space for moving the bonding tool, and also reduces the positional accuracy required on the control electrode 3 side. In other words, it is easy to connect the control electrode 3 and the control electrode-side terminal 4b, and a semiconductor device 100a with improved reliability can be obtained.

[0070] The semiconductor device 100a includes a heat sink 8, an insulating sheet 9a, a metal foil 9b, and a sealing resin 6. The heat sink 8 has a first heat sink surface 81s and a second heat sink surface 82s. The first heat sink surface 81s carries the semiconductor element 1a. The second heat sink surface 82s is disposed on the opposite side of the first heat sink surface 81s. The insulating sheet 9a is connected to the second heat sink surface 82s. The metal foil 9b is connected to the insulating sheet 9a. The sealing resin 6 seals the semiconductor element 1a inside.

[0071] This improves the insulating properties of the semiconductor device 100a, and reduces the influence of the external environment such as humidity and contamination.

[0072] In the semiconductor device 100a, at least a portion of the main electrode side terminals 4a and the control electrode side terminals 4b are disposed outside the sealing resin 6. This facilitates the formation of the sealing resin 6 by transfer molding.

[0073] In the semiconductor device 100a, a portion of the control electrode terminal 4b overlaps the first heat sink surface 81s in a plan view of the first heat sink surface 81s, which solves the problem of dead space that occurs when connecting wires and is required for moving a joining tool, and allows the semiconductor device 100a to be made smaller.

[0074] In the semiconductor device 100a, the thickness of the metal plate 5 is smaller than the thickness of the control electrode side terminal 4b. This allows for a reduction in manufacturing costs by making the metal plate 5 thinner. Furthermore, using a thin metal plate 5 improves the formability of the metal plate 5.

[0075] In the semiconductor device 100a, the metal plate 5 has a first step portion 51 at the other end 5b. The metal plate 5 is connected to the control electrode side terminal 4b at the first step portion 51. This configuration makes it possible to suppress misalignment when connecting the metal plate 5 and the control electrode side terminal 4b.

[0076] In the semiconductor device 100a, the control electrode side terminal 4b has a second step portion 41. The control electrode side terminal 4b is connected to the metal plate 5 at the second step portion 41. This configuration makes it possible to suppress misalignment when connecting the metal plate 5 and the control electrode side terminal 4b.

[0077] In the semiconductor device 100a, the metal plate 5 has a first step portion 51 at the other end 5b. The control electrode side terminal 4b has a second step portion 41. The first step portion 51 is connected to the second step portion 41. This configuration makes it possible to suppress misalignment when connecting the metal plate 5 and the control electrode side terminal 4b.

[0078] In the semiconductor device 100a, a convex portion 52 is formed at the other end 5b. A concave portion 42 is formed in the control electrode side terminal 4b. The convex portion 52 can be inserted into the concave portion 42. This makes it possible to prevent misalignment when connecting the metal plate 5 and the control electrode side terminal 4b.

[0079] In the semiconductor device 100a, the control electrode side terminal 4b has a protrusion 43 formed thereon. The other end 5b has a recess 53 formed therein. The protrusion 43 can be inserted into the recess 53. This configuration makes it possible to prevent misalignment when connecting the metal plate 5 and the control electrode side terminal 4b.

[0080] In the semiconductor device 100a, the control electrode 3 has a first bonding interface 3s with the second bonding portion 72. The metal plate 5 has a second bonding interface 5s with the second bonding portion 72. In a plan view of the first bonding interface 3s, an outer periphery 3l of the first bonding interface 3s is larger than an outer periphery 5l of the second bonding interface 5s.

[0081] In this way, when forming the second joint portion 72, a fillet is naturally formed on the side surface of the second joint portion 72. As a result, the thermal stress applied to the thermal stress concentration points in the control electrode 3 and the second joint portion 72 is reduced, and resistance to thermal fatigue is improved.

[0082] A manufacturing method of a semiconductor device 100a according to the present disclosure includes a step (S1a) of preparing a semiconductor element 1a having a plurality of control electrodes 3, a plurality of control electrode side terminals 4b, and a metal plate assembly 50, a step (S2a) of connecting the metal plate assembly 50 to the control electrodes 3 and the control electrode side terminals 4b, and a step (S3a) of cutting the metal plate assembly 50.

[0083] In this way, the metal plates 5 are positioned all at once, thereby shortening the manufacturing process of the semiconductor device 100a. Furthermore, the positional accuracy required on the control electrode 3 side can be reduced compared to DLB connection. As a result, the semiconductor device 100a can be obtained that solves problems that occur with wire connection, such as wire breakage due to thermal fatigue, the complication of the manufacturing process when DLB connection is used on the main electrode 2 side, and the occurrence of dead space for moving the bonding tool.

[0084] The method for manufacturing the semiconductor device 100a according to the present disclosure includes a step (S1b) of preparing a semiconductor element 1a having a plurality of control electrodes 3, a plurality of control electrode-side terminals 4b, and a plurality of metal plates 5, and a step (S2b) of connecting the metal plates 5 to the control electrodes 3 and the control electrode-side terminals 4b. The plurality of metal plates 5 are connected to each other by adhesive portions 56.

[0085] In this way, the metal plates 5 are positioned all at once, thereby shortening the manufacturing process of the semiconductor device 100a. Furthermore, the positional accuracy required on the control electrode 3 side can be reduced compared to DLB connection. As a result, the semiconductor device 100a can be obtained that solves problems that occur with wire connection, such as wire breakage due to thermal fatigue, the complication of the manufacturing process when DLB connection is used on the main electrode 2 side, and the occurrence of dead space for moving the bonding tool.

[0086] Second Embodiment <Configuration of Semiconductor Device> Figure 16 is a schematic partial plan view of a semiconductor device 100b according to a second embodiment. The semiconductor device 100b shown in Figure 16 basically has the same configuration as the semiconductor device 100a shown in Figures 1 and 2 and can achieve the same effects, but differs in that the width in the y direction of the metal plate 5 is not uniform. Specifically, the width w2 in the y direction of the other end 5b of the metal plate 5 is larger than the width w1 in the y direction of the one end 5a.

[0087] In plan view, the width of the metal plate 5 in the y direction may gradually increase from the control electrode 3 toward the control electrode side terminal 4b.

[0088] In this way, when connecting the metal plate 5 and the control electrode side terminal 4b, a large clearance can be ensured to prevent misalignment of the metal plate 5 and the control electrode side terminal 4b.

[0089] <Effects> In the semiconductor device 100b, the y direction is defined as the direction perpendicular to the direction in which the metal plate 5 extends toward the control electrode terminal 4b in a plan view of the semiconductor element 1a. The width w2 of the metal plate 5 in the y direction at the other end 5b is greater than the width w1 of the one end 5a in the y direction.

[0090] In this way, when connecting the metal plate 5 and the control electrode side terminal 4b, a large clearance can be ensured to prevent misalignment of the metal plate 5 and the control electrode side terminal 4b.

[0091] Third Embodiment <Configuration of Semiconductor Device> Figure 17 is a schematic plan view of a semiconductor device 100c according to a third embodiment. Figure 17 corresponds to Figure 1. Figure 18 is a schematic cross-sectional view of the semiconductor device 100c taken along line XVIII-XVIII in Figure 17. Figure 18 corresponds to Figure 2. The semiconductor device 100c shown in Figures 17 and 18 basically has the same configuration as the semiconductor device 100a shown in Figures 1 and 2 and can achieve the same effects, but differs in that an insulating substrate 11 is used instead of the heat sink 8. If the thermal conductivity of the insulating substrate 11 is sufficiently ensured and the thermal resistance is small, the heat sink 8 for the purpose of heat diffusion may not be used.

[0092] The insulating substrate 11 has a metal circuit pattern 11a, a ceramic substrate 11b, and a metal foil 11c. As shown in Figures 17 and 18, the semiconductor element 1 is mounted on the metal circuit pattern 11a. The metal circuit pattern 11a is connected to the ceramic substrate 11b. The metal foil 11c is connected to the surface of the ceramic substrate 11b opposite to the surface to which the metal circuit pattern 11a is connected. The surface of the metal foil 11c opposite to the surface connected to the ceramic substrate 11b is exposed from the sealing resin 6.

[0093] The material constituting the ceramic substrate 11b may be, for example, DBC (Direct Bonding Copper). The material constituting the ceramic substrate 11b preferably contains, for example, any one selected from the group consisting of alumina, aluminum nitride, and silicon nitride.

[0094] The materials constituting the metal circuit pattern 11 a and the metal foil 11 c may be any materials that can be bonded by direct bonding or active metal bonding, and are preferably, for example, thin films of copper, which is a material with high electrical conductivity.

[0095] The direct bonding method is a method of bonding two constituent materials by a direct reaction. For example, the two constituent materials may be a ceramic substrate 11b and a metal circuit pattern 11a. For example, the two constituent materials may be a ceramic substrate 11b and a metal foil 11c.

[0096] The active metal bonding method is a method of bonding two constituent materials with a brazing material containing an active metal such as titanium or zirconium. For example, the two constituent materials may be a ceramic substrate 11b and a metal circuit pattern 11a, or the two constituent materials may be a ceramic substrate 11b and a metal foil 11c, using the active metal bonding method.

[0097] This makes it possible to insulate the back surface of the semiconductor element 1. As a result, it becomes possible to form more complex semiconductor circuits.

[0098] Fourth Embodiment <Configuration of Semiconductor Device> Fig. 19 is a schematic plan view of a semiconductor device 100d according to a fourth embodiment. Fig. 19 corresponds to Fig. 17. Fig. 20 is a schematic cross-sectional view of the semiconductor device 100d taken along line XX-XX in Fig. 19. Fig. 20 corresponds to Fig. 18. The semiconductor device 100d shown in Figs. 19 and 20 basically has the same configuration as the semiconductor device 100c shown in Figs. 17 and 18 and can achieve the same effects, but differs in that a sealing resin 6 is formed by a case mold. For example, a potting resin is used as the sealing resin 6.

[0099] Specifically, insulating substrate 11 is connected onto heat sink 8 via sixth joint 76. As shown in Figures 19 and 20, case 12 is disposed so as to surround insulating substrate 11. Case 12 is connected to heat sink 8.

[0100] Each terminal is insert-molded in advance into the case 12. Specifically, the main electrode side terminal 4a, the control electrode side terminal 4b, and a portion of the heat sink side terminal 4d are disposed inside the case 12 and extend in the z direction.

[0101] The material of case 12 is preferably injection moldable and has high heat resistance and insulating properties, and may be any material selected from the group consisting of polyphenylene sulfide, polybutylene terephthalate, liquid crystal resin, and fluorine-based resin.

[0102] When the sealing resin 6 is a potting resin, the material constituting the sealing resin 6 is preferably, for example, an epoxy resin filled with silica powder. The potting resin preferably has fluidity that allows potting at room temperature or a temperature close to room temperature. Therefore, the composition of the epoxy resin matrix and the content and particle size distribution of the silica powder to be filled may be adjusted. In order to improve the heat dissipation properties of the potting resin, alumina powder filler may be used instead of silica powder.

[0103] When the sealing resin 6 is formed by transfer molding, the size of the mold is limited, making it difficult to obtain a large semiconductor device. On the other hand, when the sealing resin 6 is formed by case molding as described above, a large semiconductor device 100d can be obtained.

[0104] Fifth Embodiment Here, a power conversion device to which the semiconductor devices described in the above-mentioned first to fifth embodiments are applied will be described. Although the present disclosure is not limited to a specific power conversion device, the following will describe a case in which the present disclosure is applied to a three-phase inverter as the fifth embodiment.

[0105] Fig. 21 is a block diagram showing the configuration of a power conversion system to which the power conversion device according to this embodiment is applied. The power conversion system shown in Fig. 21 is composed of a power supply 400, a power conversion device 200, and a load 300. The power supply 400 is a DC power supply and supplies DC power to the power conversion device 200. The power supply 400 can be composed of various elements, such as a DC system, a solar cell, or a storage battery. It may also be composed of a rectifier circuit or an AC / DC converter connected to an AC system. The power supply 400 may also be composed of a DC / DC converter that converts DC power output from the DC system into a predetermined power.

[0106] The power conversion device 200 is a three-phase inverter connected between a power source 400 and a load 300, and converts DC power supplied from the power source 400 into AC power and supplies the AC power to the load 300. As shown in Fig. 21 , the power conversion device 200 includes a main conversion circuit 201 that converts DC power into AC power and outputs it, and a control circuit 203 that outputs a control signal to the main conversion circuit 201 to control the main conversion circuit 201.

[0107] The load 300 is a three-phase electric motor that is driven by AC power supplied from the power conversion device 200. The load 300 is not limited to a specific application, but is an electric motor mounted on various electrical devices, and is used as an electric motor for, for example, a hybrid vehicle, an electric vehicle, a railroad car, an elevator, or an air conditioning device.

[0108] The power conversion device 200 will be described in detail below. The main conversion circuit 201 includes switching elements and freewheel diodes (neither of which is shown). When the switching elements are switched, DC power supplied from the power source 400 is converted into AC power and supplied to the load 300. There are various specific circuit configurations for the main conversion circuit 201, but the main conversion circuit 201 according to this embodiment is a two-level three-phase full-bridge circuit that can be configured from six switching elements and six freewheel diodes connected in anti-parallel to each switching element.

[0109] The semiconductor device 100a, 100b, 100c, or 100d according to at least one of the above-described first to fourth embodiments is configured as a semiconductor module 202, with at least one of the switching elements and freewheeling diodes of the main conversion circuit 201. Six switching elements are connected in series in pairs to form upper and lower arms, each of which constitutes a phase (U phase, V phase, or W phase) of a full-bridge circuit. The output terminals of each upper and lower arm, i.e., the three output terminals of the main conversion circuit 201, are connected to a load 300.

[0110] The main conversion circuit 201 also includes a drive circuit (not shown) that drives each switching element. The drive circuit may be built into the semiconductor module 202, or may be provided separately from the semiconductor module 202. The drive circuit generates drive signals that drive the switching elements of the main conversion circuit 201 and supplies them to the control electrodes of the switching elements of the main conversion circuit 201. Specifically, in accordance with control signals from a control circuit 203 (described later), the drive circuit outputs to the control electrodes of each switching element a drive signal that turns the switching element on and a drive signal that turns the switching element off. To maintain a switching element in the on state, the drive signal is a voltage signal (on signal) that is equal to or greater than the threshold voltage of the switching element, and to maintain a switching element in the off state, the drive signal is a voltage signal (off signal) that is equal to or less than the threshold voltage of the switching element.

[0111] The control circuit 203 controls the switching elements of the main conversion circuit 201 so that the desired power is supplied to the load 300. Specifically, it calculates the time (on time) that each switching element of the main conversion circuit 201 should be in the on state based on the power to be supplied to the load 300. For example, the main conversion circuit 201 can be controlled by PWM control, which modulates the on time of the switching elements according to the voltage to be output. The control circuit 203 then outputs a control command (control signal) to a drive circuit included in the main conversion circuit 201 so that an on signal is output to a switching element that should be in the on state at each time point, and an off signal is output to a switching element that should be in the off state at each time point. In accordance with this control signal, the drive circuit outputs an on signal or an off signal as a drive signal to the control electrode of each switching element.

[0112] In the power conversion device of this embodiment, the semiconductor devices 100a, 100b, 100c, and 100d of the above-mentioned embodiments 1 to 4 are applied as semiconductor modules 202 to at least one of the switching elements and freewheel diodes of the main conversion circuit 201, thereby improving electrical insulation and improving the reliability of the power conversion device.

[0113] In the present embodiment, an example in which the present disclosure is applied to a two-level three-phase inverter has been described, but the present disclosure is not limited to this and can be applied to various power conversion devices. In the present embodiment, a two-level power conversion device is described, but a three-level or multi-level power conversion device may also be used. When supplying power to a single-phase load, the present disclosure may also be applied to a single-phase inverter. Furthermore, when supplying power to a DC load, etc., the present disclosure may also be applied to a DC / DC converter or an AC / DC converter.

[0114] Furthermore, the power conversion device to which the present disclosure is applied is not limited to cases in which the above-mentioned load is an electric motor, but can also be used, for example, as a power supply device for an electric discharge machine, a laser processing machine, an induction heating cooker, or a non-contact power supply system, and can also be used as a power conditioner for a solar power generation system, a power storage system, etc.

[0115] The semiconductor devices described in the respective embodiments can be combined in various ways as needed. In addition, the dependent claims described in the claims also have dependent aspects corresponding to the combinations.

[0116] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. Unless there is a contradiction, at least two of the embodiments disclosed herein may be combined. The basic scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0117] REFERENCE SIGNS LIST 1, 1a, 1b Semiconductor element, 2, 2a, 2b Main electrode, 3 Control electrode, 3l Outer periphery, 3s First bonding interface, 4a Main electrode side terminal, 4b Control electrode side terminal, 4c, 4d Heat sink side terminal, 5 Metal plate, 5a One end, 5b Other end, 5l Outer periphery, 5s Second bonding interface, 6 Sealing resin, 7 Bonding portion, 8 Heat sink, 9a Insulating sheet, 9b Metal foil, 11 Insulating substrate, 11a Metal circuit pattern, 11b Ceramic substrate, 11c Metal foil, 12 Case, 41 Second step portion, 41s1 First step surface, 41s2 Second step surface, 42 Convex portion, 43 Convex portion, 50 Metal plate assembly, 51 First step portion, 51s1 First step surface, 51s2 Second step surface, 52 Convex portion, 53 Convex portion, 55 Common part, 56 adhesive part, 71a, 71b first joint part, 72 second joint part, 73 third joint part, 74a, 74b fourth joint part, 76 sixth joint part, 81s first heat sink surface, 82s second heat sink surface, 100a, 100b, 100c, 100d semiconductor device, 200 power conversion device, 201 main conversion circuit, 202 semiconductor module, 203 control circuit, 300 load, 400 power supply, L cutting line, w1 width, w2 width.

Claims

1. A semiconductor device comprising: a semiconductor element having a main electrode and a control electrode; a main electrode side terminal connected to the main electrode; and a metal plate connected to the control electrode.

2. The semiconductor device according to claim 1, wherein the main electrode and the main electrode side terminal are connected via a first joint, and the control electrode and the metal plate are connected via a second joint.

3. The semiconductor device according to claim 2, further comprising a control electrode side terminal, the metal plate having one end connected to the control electrode and another end located opposite the one end, the control electrode side terminal being connected to the other end via a third joint.

4. The semiconductor device described in claim 3, comprising: a heat sink having a first heat sink surface on which the semiconductor element is mounted and a second heat sink surface arranged on the opposite side of the first heat sink surface; an insulating sheet connected to the second heat sink surface; metal foil connected to the insulating sheet; and a sealing resin that seals the semiconductor element inside.

5. The semiconductor device according to claim 4, wherein at least a portion of said main electrode side terminal and said control electrode side terminal are disposed outside said sealing resin.

6. The semiconductor device according to claim 4 or 5, wherein a portion of said control electrode side terminal overlaps said first heat sink surface in a plan view of said first heat sink surface.

7. The semiconductor device according to claim 3, wherein the thickness of the metal plate is smaller than the thickness of the control electrode side terminal.

8. A semiconductor device according to any one of claims 3 to 7, wherein the metal plate has a first step portion at the other end, and the metal plate is connected to the control electrode side terminal at the first step portion.

9. A semiconductor device according to any one of claims 3 to 7, wherein the control electrode side terminal has a second step portion, and the control electrode side terminal is connected to the metal plate at the second step portion.

10. A semiconductor device according to any one of claims 3 to 7, wherein the metal plate has a first step portion at the other end, the control electrode side terminal has a second step portion, and the first step portion is connected to the second step portion.

11. A semiconductor device according to any one of claims 3 to 10, wherein a convex portion is formed at the other end, and a concave portion is formed in the control electrode side terminal, and the convex portion can be inserted into the concave portion.

12. A semiconductor device according to any one of claims 3 to 10, wherein the control electrode side terminal has a protrusion formed thereon, and the other end has a recess formed therein, and the protrusion can be inserted into the recess.

13. A semiconductor device according to any one of claims 3 to 12, wherein, in a plan view of the semiconductor element, a direction perpendicular to a direction in which the metal plate extends toward the control electrode side terminal is defined as a y direction, and the width of the metal plate in the y direction at the other end is greater than the width of the metal plate in the y direction at the one end.

14. A semiconductor device as claimed in any one of claims 2 to 13, wherein the control electrode has a first bonding interface with the second bonding portion, the metal plate has a second bonding interface with the second bonding portion, and in a planar view at the first bonding interface, the outer periphery of the first bonding interface is larger than the outer periphery of the second bonding interface.

15. A power conversion device comprising: a main conversion circuit having a semiconductor device according to any one of claims 1 to 14, which converts input power and outputs it; and a control circuit which outputs a control signal for controlling said main conversion circuit to said main conversion circuit.

16. A method for manufacturing a semiconductor device, comprising the steps of: preparing a semiconductor element having a plurality of control electrodes, a plurality of control electrode side terminals, and a metal plate assembly; connecting the metal plate assembly to the control electrodes and the control electrode side terminals; and cutting the metal plate assembly.

17. A method for manufacturing a semiconductor device, comprising the steps of: preparing a semiconductor element having a plurality of control electrodes, a plurality of control electrode side terminals, and a plurality of metal plates; and connecting the metal plates to the control electrodes and the control electrode side terminals, wherein the plurality of metal plates are connected to each other by adhesive joints.

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