JP7487695B2 - Semiconductor Device - Google Patents

Description

This disclosure relates to a semiconductor device.

In semiconductor devices such as power modules used in inverters, it is important to efficiently dissipate heat generated in the semiconductor elements when current is applied. In conventional semiconductor devices, screw fastening holes are provided in the case, and the semiconductor device and heat sink are attached closely by fastening with screws, allowing heat generated in the semiconductor elements to be dissipated from the heat sink (for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 8-162572

However, in the semiconductor device of Patent Document 1, the bushing provided as the screw fastening hole is molded into the case, and when the screw is fastened, the bushing moves in the direction in which the screw is fastened, causing the fastening stress of the screw to be transmitted to the case, resulting in the case cracking.

The present disclosure has been made to solve the above-mentioned problems, and aims to provide a semiconductor device that prevents the bush from moving in the direction in which the screw is tightened when the screw is tightened, thereby preventing the case from cracking.

The semiconductor device according to the present disclosure comprises an insulating substrate having a first main surface and a second main surface opposite to the first main surface, the insulating substrate having a circuit pattern constituting the first main surface, a heat sink constituting the second main surface, and an insulating member provided between the circuit pattern and the heat sink, a semiconductor element provided on the circuit pattern via a bonding member, a case connected to an end of the insulating substrate via an adhesive, exposing the second main surface of the insulating substrate and surrounding the insulating substrate and the semiconductor element, and a metal bush provided at the end of the case, penetrating the end of the case in a direction from the first main surface to the second main surface, and having a through hole therein in a direction from the first main surface to the second main surface, the through hole being cylindrical in shape with a constant inner diameter in the direction from the first main surface to the second main surface, and having an anchor portion whose outer diameter narrows in the direction from the first main surface to the second main surface and which is fixed to the case, the anchor portion having an arc-like shape with an outer diameter expanding at the center of the metal bush.

In the semiconductor device disclosed herein, the metal bushing has an anchor portion whose outer diameter narrows in the direction of travel when the screw is tightened, making it possible to prevent the bushing from moving in the direction of travel when the screw is tightened.

1 is a plan view showing a semiconductor device according to a first embodiment; 1 is a cross-sectional view showing a semiconductor device according to a first embodiment; 1 is an electric circuit diagram showing a configuration of a semiconductor device according to a first embodiment; 1 is a cross-sectional view showing a configuration in which a semiconductor device according to a first embodiment is attached to a heat sink; FIG. 2 is a partial enlarged view showing the configuration of a metal bush of the semiconductor device according to the first embodiment. FIG. 11 is an enlarged cross-sectional view showing a configuration of a metal bush of a semiconductor device according to a second embodiment. FIG. 11 is a block diagram showing a configuration of a power conversion device according to a third embodiment.

The following describes the embodiments with reference to the drawings. The drawings are schematic, and the relative sizes and positions may be changed. In the following description, the same or corresponding components are given the same reference numerals, and repeated description may be omitted.

In addition, in the following description, terms that indicate specific positions and directions, such as "top," "bottom," "front," "back," "left," "right," and "side," may be used. However, these terms are used for convenience to make it easier to understand the contents of the embodiments, and do not limit the positions and directions when implemented.

<First embodiment>
A semiconductor device 50 according to the first embodiment will be described below. Fig. 1 is a plan view showing the semiconductor device according to the first embodiment.

As shown in FIG. 1, the semiconductor device 50 has eight cylindrical metal bushes 10 at the left and right ends of the case 3, which is rectangular in plan view, and is provided on the upper surface of the case 3. The metal bushes 10 have through holes so that bolts that are screwed into a heat sink or the like can be inserted when the semiconductor device 50 is incorporated into an inverter unit. The semiconductor device 50 may be fastened to the inverter unit by screws via the metal bushes 10 and washers. The material of the metal bushes 10 may be any metal such as copper or iron, but metals that are easy to process and have low material costs, such as brass or aluminum, are preferable. The case 3 is a case in which the metal bushes 10 are embedded and insert-molded, but it may also be outsert-molded, in which the metal bushes 10 are fixed by press-fitting into through-holes that penetrate the case.

The metal bushes 10 are provided in one row on each side of the case 3, with the row of metal bushes 10 on the left side of the case 3 and the row of metal bushes 10 on the right side of the case 3 arranged in two parallel rows. The metal bushes 10 are also arranged at equal intervals within each row. Note that the number of metal bushes 10 needs to be two or more, and is of course not limited to eight. It is also possible to provide only one metal bush 10 at each of the four corners of the case 3. Furthermore, the metal bushes 10 do not need to be arranged parallel to each other and at equal intervals.

Electrodes 5a, 5b, and 5c are electrodes for electrically connecting the semiconductor device 50 to an external device, and are provided on the upper surface of the case 3. Electrode 5a is the P terminal of the semiconductor device 50, and electrode 5b is the N terminal of the semiconductor device 50. DC power is input between electrodes 5a and 5b from an external device such as a power supply device. Electrode 5c is the output terminal of the semiconductor device 50, and switches and outputs the DC power input from electrodes 5a and 5b to an external device such as a load device. Electrodes 5a, 5b, and 5c are provided on parallel sides facing each other on the upper surface of the case 3, and are provided on sides perpendicular to the side on which the row of metal bushes 10 on the upper surface of the case 3 is provided. Note that electrodes 5a, 5b, and 5c do not have to be provided on parallel sides facing each other on the upper surface of the case 3, and do not have to be provided perpendicular to the side on which the row of metal bushes 10 is provided. Therefore, they may be provided on the side on which the row of metal bushes is provided. Also, although electrodes 5a, 5b, and 5c are described as having three electrodes, the number of electrodes may be two or more.

The signal terminals 6 are terminals used for inputting and outputting electrical signals between the semiconductor device 50 and an external device. The signal terminals 6 are exposed from the sealing material 4. The signal terminals 6 may be provided on the upper surface of the case 3. The number of signal terminals may be one or more, and is not limited to six. The signal terminals 6 are provided between the rows of metal bushes 10 provided on the left and right sides of the case 3, and the signal terminals 6 are arranged in two rows parallel to the row of metal bushes 10 provided on the left side of the case 3 and the row of metal bushes 10 provided on the right side of the case 3. The signal terminals 6 are arranged parallel to each other, but they do not have to be arranged parallel to each other. The signal terminals 6 are not arranged at equal intervals from each other, but they may be arranged at equal intervals.

Figure 2 is a cross-sectional view showing a semiconductor device according to the first embodiment of the present disclosure. Figure 2 is a cross-sectional view of the semiconductor device 50 shown in Figure 1 taken along dashed line A-A. As shown in Figure 2, the semiconductor device 50 includes a semiconductor element 1, an insulating substrate 2, a case 3, a sealing material 4, an electrode 5, a signal terminal 6, a metal bush 10, and an anchor portion 11.

The semiconductor element 1 may be a switching element or a diode, for example, an insulated gate bipolar transistor (IGBT) or a metal-oxide-semiconductor field-effect transistor (MOSFET), and a diode may be used as the reflux element. The number of semiconductor elements is not necessarily limited to one, but may be two or more.

The insulating substrate 2 is composed of a metal plate 2a, an insulating member 2b, and a circuit pattern 2c. The semiconductor element 1 is joined to the circuit pattern 2c via solder, which is a conductive member 9. The insulating member 2b is provided on the metal plate 2a, and the insulating member 2b and the metal plate 2a are joined, for example, by solder or brazing material. The circuit pattern 2c is provided on the insulating member 2b, and the insulating member 2b and the circuit pattern 2c are joined, for example, by solder or a sintered material such as metal particles. The metal plate 2a and the circuit pattern 2c may be made of any metal, for example, copper. The metal plate 2a is a heat sink that dissipates heat generated by the semiconductor element 1, and the circuit pattern 2c forms an electric circuit of the semiconductor device 50. The insulating member 2b ensures electrical insulation from the outside of the semiconductor device 50, and may be made of, for example, an inorganic ceramic material, or may be made of a material in which ceramic powder is dispersed in a thermosetting resin such as an epoxy resin, or may be in the form of a sheet.

1, the electrodes 5 are the electrode 5a which is the P terminal of the semiconductor device 50, the electrode 5b which is the N terminal of the semiconductor device 50, and the electrode 5c which is the output terminal of the semiconductor device 50. One end of the electrode 5 is electrically connected to the semiconductor element 1 via the circuit pattern 2c, and the other end is used for electrically connecting the semiconductor device 50 to an external device. One end of the signal terminal 6 is electrically connected to the control electrode on the surface of the semiconductor element 1 via a conductive wire 7, and the other end is used for inputting and outputting electrical signals to and from the external device of the semiconductor device 50. The circuit pattern 2c may or may not be passed through. The electrodes 5 and the signal terminals 6 may be conductive, and may be made of copper, for example. The control electrode may be provided in addition to the gate electrode for controlling the on/off of the semiconductor element 1, and may be, for example, a current sense electrode or a Kelvin emitter electrode. The current sense electrode is an electrode for detecting the current flowing in the cell region of the semiconductor device 50, and the Kelvin emitter electrode is an electrode for measuring the temperature of the semiconductor device 50. Therefore, a plurality of signal terminals 6 may be provided corresponding to the control electrodes.

The semiconductor element 1 and the insulating substrate 2 are surrounded by the case 3. The case 3 is fixed via the end of the insulating member 2b and the adhesive 8, and the adhesive 8 is provided on the four sides of the insulating member 2b corresponding to the shape of the rectangular case 3 in order to fix the rectangular case 3 in a plan view. The adhesive 8 may be provided so that the sealing material 4 does not leak from between the insulating substrate 2 and the case 3 when the sealing material 4 is filled in the case as a result of the insulating substrate 2 and the case 3 being connected. In addition, the insulating member 2b and the case 3 are fixed with an adhesive, but the metal plate 2a or the circuit pattern 2c may be fixed to the case 3 with an adhesive. The case 3 is formed of an insulator such as PPS (Poly Phenylene Sulfide Resin).

The semiconductor element 1, insulating substrate 2, electrodes 5, signal terminals 6, and conductive wires 7, which are surrounded by the case 3, are covered with the sealing material 4. The ends of the electrodes 5 and signal terminals 6 are exposed from the sealing material 4 in order to connect to an external device of the case 3. In the first embodiment, an outsert case structure is described in which the case 3, the electrodes 5, and the signal terminals 6 are fixed to the case by press-fitting or screwing, but an insert case structure in which the electrodes 5 and the signal terminals 6 are embedded inside the case and the electrodes 5 and the signal terminals 6 are integrated with the case may be used. In addition, the back surface of the insulating substrate 2 is exposed from the sealing material 4 in order to be cooled by a heat sink or the like. The sealing material 4 is not particularly limited as long as it is a material having insulating properties, but it may be, for example, silicone gel or epoxy resin, or may be direct potting resin sealed with liquid epoxy resin. In the case of direct potting resin, etc., a lid or case, which is a member provided on the top of the sealing material to protect the sealing material such as silicone gel, may not be required.

Figure 3 is an electrical circuit diagram showing the configuration of a semiconductor device according to the first embodiment of the present disclosure. As shown in Figure 3, in the semiconductor device 50, when the semiconductor element is an IGBT, a diode is positioned on the circuit pattern, and two sets of circuits in which an IGBT and a diode are connected in parallel are prepared and connected in series to form a half-bridge circuit of a 2-in-1 module.

The electrode 5a is electrically connected to the collector electrode 31a, which is the back electrode of the semiconductor element 1a, via the circuit pattern 2c or conductive wire 7. The collector electrode 31a of the semiconductor element 1a and the cathode electrode 35a of the diode 15a are electrically connected to each other via the conductive wire 7 or circuit pattern 2c, and the emitter electrode 32a, which is the front electrode of the semiconductor element 1a, and the anode electrode of the diode 15a are electrically connected to each other via the conductive wire 7 or circuit pattern 2c, forming a parallel circuit of the semiconductor element 1a and the diode 15a. The electrode 5b is electrically connected to the emitter electrode 32b of the semiconductor element 1b via the circuit pattern 2c or conductive wire 7. In addition, the emitter electrode 32b, which is the surface electrode of the semiconductor element 1b, and the cathode electrode 35b of the diode 15b are electrically connected via a conductive wire 7 or a circuit pattern 2c, and the collector electrode 31b of the semiconductor element 1a and the anode electrode 36b of the diode 15b are electrically connected via a conductive wire 7 or a circuit pattern 2c, forming a parallel circuit of the semiconductor element 1b and the diode 15b. The electrode 5c is electrically connected to the emitter electrode 32a of the semiconductor element 1a and the emitter electrode 32b of the semiconductor element 1b via a conductive wire 7 or a circuit pattern 2c.

Two parallel circuits are formed, one of which is the upper arm and the other is the lower arm, which are connected in series with the upper arm to form a half-bridge circuit of a 2-in-1 module. Of course, a circuit different from the circuit configuration described above may be configured, for example, a parallel circuit of a 1-in-1 module or a three-phase inverter circuit of a 6-in-1 module may be formed. Note that, depending on the circuit configuration, the electrode 5c may not be necessary.

Figure 4 is a cross-sectional view showing a configuration in which a semiconductor device according to the present disclosure is attached to a heat sink. The configuration in Figure 4 other than the heat sink 20 is the same as that shown in Figure 2, and Figure 4 is a cross-sectional view showing a configuration in which the semiconductor device 50 and the heat sink 20 are fastened together by screws 12.

The heat sink 20 is fixed to the semiconductor device 50 by screws 12 via the metal bush 10. The metal bush 10 has a through hole that is cylindrical and has a constant inner diameter in the direction from the front surface to the back surface of the insulating substrate 2, allowing the screw 12 to be inserted. When the semiconductor device 50 is in use, the semiconductor element 1 generates heat, so the heat sink 20 is brought into contact with the back surface of the metal plate 2a to dissipate the heat. Therefore, the semiconductor device 50 and the heat sink 20 are screwed together via the metal bush 10 by screws 12 so that the metal plate 2a and the heat sink 20 can be maintained in contact with each other.

The metal bush 10 is provided with an anchor portion 11 whose outer diameter narrows in the direction from the front surface to the back surface of the insulating substrate 2. That is, the outer diameter of the anchor portion 11 narrows in the direction of advancement when the screw 12 is tightened. The anchor portion 11 is a part of the metal bush 10, and has the function of fixing the case 3 and the metal bush 10. When the screw is tightened, the metal bush 10 moves in the direction of advancement of the screw, and the tightening stress of the screw 12 is directly transmitted to the resin case 3, preventing the case from cracking. In the plan view of FIG. 1, the inner and outer diameters of the metal bush 10 are concentric circles within the range of manufacturing tolerance.

Figure 5 is a partially enlarged view showing the configuration of the metal bush of the semiconductor device according to the first embodiment of the present disclosure. Figure 5 is a partially enlarged view showing the configuration of the metal bush of the semiconductor shown in Figure 2, and shows an enlarged view of the area surrounded by the dashed line 30.

As shown in FIG. 5, the anchor portion 11 may have a taper in which the outer diameter narrows in the direction of travel when the screw is fastened to the case 3. The taper has an angle θ between the taper and the top surface of the case 3 that is less than 45°. In other words, if the flat top surface of the metal bush 10 is parallel to the top surface of the case 3 on which the metal bush 10 is provided, it can be said that the angle between the flat top end of the metal bush 10 and the taper is less than 45°. Note that even if the flat top end of the metal bush 10 is not parallel to the top surface of the case 3 on which the metal bush 10 is provided, it is sufficient that the angle between the flat top end of the metal bush 10 and the taper is less than 45°.

In the semiconductor device 50 of the present disclosure, the anchor portion 11 of the metal bush 10 is tapered, which increases the contact area between the case 3 and the metal bush 10, prevents the metal bush 10 from moving in the direction of travel when the screw is tightened, and suppresses cracking of the case. Note that the upper surface of the case 3 on which the metal bush 10 is provided refers to the surface of the case 3 on which the metal bush 10 is provided. That is, in FIG. 2, the case 3 is formed with multiple upper surfaces in a stepped shape, but the upper surface side of the case 3 on which the metal bush 10 is provided is the upper surface of the case 3 on which the metal bush 10 is provided. Of course, the case 3 does not need to have multiple upper surfaces in a stepped shape, and may have only one upper surface.

Next, a method for manufacturing a metal bush 10 whose outer diameter narrows in the direction of travel when the screw is tightened will be described. A metal bush 10 whose outer diameter narrows in the direction of travel when the screw is tightened is manufactured by turning a thick cylindrical metal bush with a cutting tool to adjust the angle during lathe processing. In this way, an anchor portion 11 is formed in the metal bush 10, and a metal bush 10 whose outer diameter narrows in the direction of travel when the screw is tightened is manufactured. Note that a metal bush 10 having a tapered shape can also be manufactured in the same way.

As described above, in the semiconductor device according to the first embodiment, the metal bush 10 has an anchor portion whose outer diameter narrows in the direction of travel when the screw is tightened, which increases the contact area between the case 3 and the metal bush 10, prevents the metal bush 10 from moving in the direction of travel when the screw is tightened, and suppresses cracking of the plastic case.

<Embodiment 2>
Next, a semiconductor device according to a second embodiment will be described. Fig. 6 is a cross-sectional view of a metal bush 10 in a semiconductor device according to a second embodiment. In the second embodiment, the same components as those described in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 6, in the semiconductor device of the second embodiment, the anchor portion 11 has an outer diameter that narrows in the direction of travel when the screw is tightened into the case 3, and an outer diameter that widens from the center of the metal bush 10 in the direction of travel when the screw is tightened. That is, the anchor portion 11 is an arc-shaped depression toward the center of the metal bush 10. The diameter 13 of the arc-shaped depression may be larger than the resin thickness 14 at the end of the case 3 where the metal bush is provided, in other words, it may be larger than the length of the metal bush 10 in the direction of travel when the screw is tightened.

Next, a method for manufacturing the metal bush 10 having an arc-shaped dent will be described. The metal bush 10 having an arc-shaped dent is manufactured by cutting a thick cylindrical metal bush with a circular cutting tool having a diameter larger than the resin thickness of the case 3 during lathe processing. In this way, the anchor portion 11 is formed in the metal bush 10, and the metal bush 10 having an arc-shaped dent is manufactured.

As described above, in the semiconductor device according to the second embodiment, the metal bush 10 has an anchor portion 11 with an arc-shaped recess, which increases the contact area between the case 3 and the metal bush 10, prevents the metal bush 10 from moving in the direction of travel when the screw is tightened, and suppresses cracking of the plastic case.

<Third embodiment>
In this embodiment, the semiconductor device according to the above-mentioned embodiments 1 and 2 is applied to a power conversion device. Although the present invention is not limited to a specific power conversion device, a case in which the present invention is applied to a three-phase inverter will be described below as embodiment 3.

Figure 7 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. 7 is composed of a power source 100, a power conversion device 200, and a load 300. The power source 100 is a DC power source and supplies DC power to the power conversion device 200. The power source 100 can be composed of various things, for example, a DC system, a solar cell, or a storage battery, or it may be composed of a rectifier circuit connected to an AC system or an AC/DC converter. The power source 100 may also be composed of a DC/DC converter that converts the DC power output from the DC system into a specified power.

The power conversion device 200 is a three-phase inverter connected between the power source 100 and the load 300, converts DC power supplied from the power source 100 into AC power, and supplies the AC power to the load 300. As shown in FIG. 7, 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.

The load 300 is a three-phase motor driven by AC power supplied from the power conversion device 200. Note that the load 300 is not limited to a specific use, but is a motor mounted on various electrical devices, and is used, for example, as a motor for hybrid cars, electric cars, railroad cars, elevators, or air conditioning equipment.

The power conversion device 200 will be described in detail below. The main conversion circuit 201 includes switching elements and free wheel diodes (not shown), and converts DC power supplied from the power source 100 into AC power by switching the switching elements, and supplies the AC power to the load 300. There are various specific circuit configurations of the main conversion circuit 201, but the main conversion circuit 201 according to this embodiment is a two-level three-phase full bridge circuit, and can be configured with six switching elements and six free wheel diodes connected in reverse parallel to each switching element. The semiconductor device according to any of the above-mentioned embodiments 1 and 2 is applied to at least one of the switching elements and free wheel diodes of the main conversion circuit 201. The six switching elements are connected in series with two switching elements to form upper and lower arms, and each upper and lower arm forms each phase (U phase, V phase, W phase) of the 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 the load 300.

The main conversion circuit 201 also includes a drive circuit (not shown) that drives each switching element, but the drive circuit may be built into the power module 202, or may be configured to include a drive circuit separate from the power module 202. The drive circuit generates a drive signal that drives the switching element of the main conversion circuit 201 and supplies it to the control electrode of the switching element of the main conversion circuit 201. Specifically, in accordance with a control signal from the control circuit 203 described later, a drive signal that turns the switching element on and a drive signal that turns the switching element off are output to the control electrode of each switching element. When the switching element is maintained in the on state, the drive signal is a voltage signal (on signal) that is equal to or higher than the threshold voltage of the switching element, and when the switching element is maintained in the off state, the drive signal is a voltage signal (off signal) that is equal to or lower than the threshold voltage of the switching element.

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, the time (on time) that each switching element of the main conversion circuit 201 should be in the on state is calculated based on the power to be supplied to the load 300. For example, the main conversion circuit 201 can be controlled by PWM control that modulates the on time of the switching elements according to the voltage to be output. Then, a control command (control signal) is output to the drive circuit provided in the main conversion circuit 201 so that an on signal is output to the switching element that should be in the on state at each point in time, and an off signal is output to the switching element that should be in the off state. The drive circuit outputs an on signal or an off signal as a drive signal to the control electrode of each switching element according to this control signal.

In the power conversion device according to this embodiment, the semiconductor devices according to the first and second embodiments are used as the switching elements and free wheel diodes of the main conversion circuit 201, and the metal bush 10 has an anchor portion whose outer diameter narrows in the direction of travel when the screw is tightened, which has the effect of preventing the bush from moving in the direction of travel when the screw is tightened.

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

In addition, the power conversion device to which the present invention is applied is not limited to the case where the load described above 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.

The present invention allows the embodiments to be freely combined and modified or omitted as appropriate within the scope of the invention. The conductive member that joins the components may be a metal with low electrical resistance, such as solder, a metal paste using a metal filler, or a fired metal that is metallized by heat.

REFERENCE SIGNS LIST 1 (1a, 1b) Semiconductor element 2 Insulating substrate 2a Metal plate 2b Insulating member 2c Circuit pattern 3 Case 4 Sealing material 5 Electrode 5a P terminal 5b N terminal 5c Output terminal 6 Signal terminal 7 Conductive wire 8 Adhesive 9 Conductive member 10 Metal bush 11 Anchor portion 12 Screw 13 Diameter of circular arc recess 14 Resin thickness 15 (15a, 15b) Diode 20 Heat sink 50 Semiconductor device 100 Power source 200 Power conversion device 201 Main conversion circuit 202 Power module 203 Control circuit 300 Load

Claims (7)

an insulating substrate having a first main surface and a second main surface opposite to the first main surface, the insulating substrate having a circuit pattern constituting the first main surface, a heat sink constituting the second main surface, and an insulating member provided between the circuit pattern and the heat sink;
a semiconductor element provided on the circuit pattern via a bonding member;
a case connected to an end of the insulating substrate via an adhesive, exposing the second main surface of the insulating substrate and surrounding the insulating substrate and the semiconductor element;
a metal bush provided at an end of the case, penetrating the end of the case in a direction from the first main surface toward the second main surface, and having a through hole therein in a direction from the first main surface toward the second main surface;
Equipped with
the metal bushing has a cylindrical through hole having a constant inner diameter in a direction from the first main surface to the second main surface, and an anchor portion having an outer diameter narrowing in a direction from the first main surface to the second main surface and fixed to the case;
The semiconductor device according to the present invention is characterized in that the anchor portion has an arc-like shape with the outer diameter expanding from the center of the metal bush . The semiconductor device according to claim 1, wherein the anchor portion has a tapered shape in a cross-sectional view in a direction from the first main surface to the second main surface. The semiconductor device according to claim 2, wherein the tapered shape has an angle of less than 45 degrees with respect to the surface on the first main side of the case. 4. The semiconductor device according to claim 3, wherein a diameter of the arc is larger than a thickness of the end of the case at which the metal bush is provided, in a direction from the first main surface toward the second main surface. 5. The semiconductor device according to claim 1, wherein the case has a rectangular shape in a plan view, and the metal bushes are provided at four corners of the case. 6. The semiconductor device according to claim 1, further comprising a heat sink in contact with the second main surface of the insulating substrate. A main conversion circuit having the semiconductor device according to any one of claims 1 to 6 , which converts input power and outputs the converted power;
a control circuit that outputs a control signal for controlling the main conversion circuit to the main conversion circuit;
A power conversion device comprising:

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