JP7363587B2 - semiconductor equipment - Google Patents

Description

The disclosure in this specification relates to a semiconductor device.

Patent Document 1 discloses a semiconductor device. This semiconductor device includes a semiconductor element having main electrodes on both sides. The contents of the prior art documents are incorporated by reference as explanations of technical elements in this specification.

Japanese Patent Application Publication No. 2004-40899

In Patent Document 1, heat from a semiconductor element is transmitted to an insulating member through a path via a conductive member bonded to a first main electrode and a path via a conductive member bonded to a second main electrode. Each of the conductive members is bonded to an insulating member using a conductive adhesive and has a high thermal resistance. Further, the semiconductor chip forming the lower arm is mounted upside down with respect to the semiconductor chip forming the upper arm of the upper and lower arm circuits. Further improvements in power conversion devices are required in the above-mentioned aspects or in other aspects not mentioned.

One object of the disclosure is to provide a semiconductor device with excellent heat dissipation.

Another object of the disclosure is to provide a semiconductor device with a simplified structure while having high heat dissipation.

The semiconductor device disclosed herein is
A wiring board (50) made of ceramic and having an insulating base material (51) having a front surface and a back surface opposite to the front surface in the thickness direction, and a surface metal body (52) provided on the front surface;
A plurality of electrodes each having a first main electrode (41C) provided on a surface facing the front surface and a second main electrode (41E) provided on a surface opposite to the facing surface, and forming an upper and lower arm circuit. a semiconductor element (40);
A plurality of conductive members (60) joined to the second main electrode.

The plurality of semiconductor elements includes an upper arm element (40H) that constitutes an upper arm of the upper and lower arm circuit, and a lower arm element (40L) that constitutes a lower arm,
The surface metal body includes a first metal part (521) joined to the first main electrode of the upper arm element, at least one second metal part (522) electrically separated from the first metal part, The third metal part (523) joined to the first main electrode of the lower arm element, and at least one fourth metal part electrically separated from the first metal part, second metal part, and third metal part. (524);
The conductive member is joined to the second main electrode and the second metal part of the upper arm element, and the first conductive member (61) electrically connected to the third metal part, and the second conductive member (61) of the lower arm element. a second conductive member (62) joined to the main electrode and the fourth metal part;
The second metal part is a dummy wiring part that is electrically isolated from the third metal part and does not provide a wiring function,
The first conductive member is joined to the second metal portion and the third metal portion of the surface metal body.

According to the disclosed semiconductor device, heat from the upper arm element is transmitted to the insulating base material made of ceramic through the first metal part joined to the first main electrode. Further, the power is transmitted to the insulating base material via the first conductive member and the second metal part joined to the second main electrode. The first metal part and the second metal part are provided as surface metal bodies of the wiring board, and have low thermal resistance at the bonding interface with the insulating base material. Therefore, the heat generated by the upper arm element can be effectively dissipated.

Similarly, the heat of the lower arm element is transmitted to the insulating base material made of ceramic through the third metal part joined to the first main electrode. Further, the power is transmitted to the insulating base material via the second conductive member and the fourth metal part joined to the second main electrode. The third metal part and the fourth metal part are also provided as surface metal bodies, and have low thermal resistance at the bonding interface with the insulating base material. Therefore, the heat generated by the lower arm element can be effectively radiated. As a result, it is possible to provide a semiconductor device with excellent heat dissipation.

According to the disclosed semiconductor device, in both the upper arm element and the lower arm element, the first main electrode is joined to the surface metal body, and the second main electrode is joined to the conductive member. That is, in the upper arm element and the lower arm element, the first main electrode is provided on the same side surface in the plate thickness direction. Since the main electrodes are arranged in the same way, the structure can be simplified. As a result, it is possible to provide a semiconductor device with a simplified structure while having high heat dissipation.

The multiple aspects disclosed in this specification employ different technical means to achieve their respective objectives. The claims and the reference numerals in parentheses described in this section exemplarily indicate correspondence with parts of the embodiment described later, and are not intended to limit the technical scope. The objects, features, and advantages disclosed in this specification will become more apparent by reference to the subsequent detailed description and accompanying drawings.

1 is a diagram showing a circuit configuration of a power conversion device to which a semiconductor device is applied. FIG. 1 is a perspective view showing a semiconductor device according to a first embodiment. FIG. 2 is a plan view showing a wiring board in the semiconductor device. FIG. 2 is a plan view of the semiconductor device in which a sealing resin body and an extending portion are omitted. 5 is a cross-sectional view of the semiconductor device along line V-V in FIG. 4. FIG. 5 is a cross-sectional view of the semiconductor device taken along line VI-VI in FIG. 4. FIG. It is a sectional view showing a modification. It is a sectional view showing a modification. It is a sectional view showing a modification. FIG. 7 is a plan view showing a wiring board in a semiconductor device according to a second embodiment. FIG. 2 is a plan view of the semiconductor device in which a sealing resin body and an extending portion are omitted. 12 is a cross-sectional view of the semiconductor device taken along line XII-XII in FIG. 11. FIG. FIG. 7 is a cross-sectional view showing a semiconductor device according to a third embodiment. It is a sectional view showing a modification. FIG. 7 is a cross-sectional view showing a semiconductor device according to a fourth embodiment. It is a sectional view showing a modification. It is a top view which shows a modification. FIG. 7 is a cross-sectional view showing a semiconductor device according to a fifth embodiment.

A plurality of embodiments will be described with reference to the drawings. In several embodiments, functionally and/or structurally corresponding parts are provided with the same reference numerals.

The semiconductor device of this embodiment is applied, for example, to a power converter device for a moving object that uses a rotating electric machine as a drive source. The moving object is, for example, an electric vehicle such as an electric vehicle (EV), a hybrid vehicle (HV), or a fuel cell vehicle (FCV), a flying object such as a drone, a ship, a construction machine, or an agricultural machine. An example applied to a vehicle will be described below.

(First embodiment)
First, based on FIG. 1, a schematic configuration of a vehicle drive system will be described.

<Vehicle drive system>
As shown in FIG. 1, a vehicle drive system 1 includes a DC power supply 2, a motor generator 3, and a power conversion device 4.

The DC power supply 2 is a DC voltage source composed of a rechargeable and dischargeable secondary battery. The secondary battery is, for example, a lithium ion battery or a nickel metal hydride battery. The motor generator 3 is a three-phase AC rotating electric machine. The motor generator 3 functions as a driving source for the vehicle, that is, an electric motor. The motor generator 3 functions as a generator during regeneration. Power conversion device 4 performs power conversion between DC power supply 2 and motor generator 3 .

<Power converter>
Next, the circuit configuration of the power conversion device 4 will be explained based on FIG. 1. The power converter 4 includes a smoothing capacitor 5 and an inverter 6.

The smoothing capacitor 5 mainly smoothes the DC voltage supplied from the DC power supply 2. The smoothing capacitor 5 is connected to a P line 7 which is a power line on the high potential side and an N line 8 which is a power line on the low potential side. The P line 7 is connected to the positive pole of the DC power supply 2, and the N line 8 is connected to the negative pole of the DC power supply 2. A positive terminal of the smoothing capacitor 5 is connected to a P line 7 between the DC power supply 2 and the inverter 6. Similarly, the negative electrode is connected to the N line 8 between the DC power supply 2 and the inverter 6. Smoothing capacitor 5 is connected in parallel to DC power supply 2 .

Inverter 6 is a DC-AC conversion circuit. Inverter 6 converts the DC voltage into three-phase AC voltage and outputs it to motor generator 3 according to switching control by a control circuit (not shown). Thereby, the motor generator 3 is driven to generate a predetermined torque. During regenerative braking of the vehicle, the inverter 6 converts the three-phase AC voltage generated by the motor generator 3 in response to the rotational force from the wheels into a DC voltage under switching control by the control circuit, and outputs the DC voltage to the P line 7. In this way, the inverter 6 performs bidirectional power conversion between the DC power supply 2 and the motor generator 3.

The inverter 6 includes upper and lower arm circuits 9 for three phases. The upper and lower arm circuits 9 are sometimes referred to as legs. The upper and lower arm circuits 9 each have an upper arm 9H and a lower arm 9L. The upper arm 9H and the lower arm 9L are connected in series between the P line 7 and the N line 8, with the upper arm 9H on the P line 7 side. A connection point between upper arm 9H and lower arm 9L is connected to a corresponding phase winding of motor generator 3 via output line 10. Inverter 6 has six arms.

In this embodiment, an n-channel type insulated gate bipolar transistor 11 (hereinafter referred to as IGBT 11) is employed as a switching element constituting each arm. A freewheeling diode 12 is connected in antiparallel to each of the IGBTs 11. In the upper arm 9H, the collector of the IGBT 11 is connected to the P line 7. In the lower arm 9L, the emitter of the IGBT 11 is connected to the N line 8. The emitter of the IGBT 11 in the upper arm 9H and the collector of the IGBT 11 in the lower arm 9L are connected to each other. The anode of the diode 12 is connected to the emitter of the corresponding IGBT 11, and the cathode is connected to the collector.

The power conversion device 4 may further include a converter as a power conversion circuit. A converter is a DC-DC conversion circuit that converts DC voltage to DC voltages of different values. A converter is provided between DC power supply 2 and smoothing capacitor 5. The converter includes, for example, a reactor and the above-mentioned upper and lower arm circuits 9. The power conversion device 4 may include a filter capacitor that removes power supply noise from the DC power supply 2. A filter capacitor is provided between the DC power supply 2 and the converter.

The power conversion device 4 may include a drive circuit for switching elements that constitute the inverter 6 and the like. The drive circuit supplies a drive voltage to the gate of the IGBT 11 of the corresponding arm based on a drive command from the control circuit. The drive circuit drives the corresponding IGBT 11 by applying a drive voltage, that is, turns it on and turns it off. A drive circuit is sometimes referred to as a driver.

The power conversion device 4 may include a control circuit for switching elements. The control circuit generates a drive command for operating the IGBT 11 and outputs it to the drive circuit. The control circuit generates a drive command based on a torque request input from a host ECU (not shown) and signals detected by various sensors. Various sensors include, for example, a current sensor, a rotation angle sensor, and a voltage sensor. The current sensor detects the phase current flowing through the windings of each phase. The rotation angle sensor detects the rotation angle of the rotor of the motor generator 3. The voltage sensor detects the voltage across the smoothing capacitor 5. The control circuit outputs a PWM signal as a drive command. The control circuit includes, for example, a microcomputer. ECU is an abbreviation for Electronic Control Unit. PWM is an abbreviation for Pulse Width Modulation.

<Semiconductor device>
Next, a semiconductor device constituting the power conversion device 4 (inverter 6) will be described based on FIGS. 2 to 6. FIG. 2 is a perspective view of the semiconductor device 20. In FIG. 2, for convenience, the sealing resin body 30 is partially transparent to show elements inside the sealing resin body 30 and elements hidden by the sealing resin body 30. FIG. 3 is a plan view showing the wiring board 50. In FIG. 3, the semiconductor element 40 and the bonding member 80 are illustrated together. However, the description of the bonding member 80 on the emitter electrode 41E of the semiconductor element 40 is omitted for convenience. FIG. 4 is a plan view of the semiconductor device 20 with the sealing resin body 30 and the extending portion 621 omitted. FIG. 5 is a cross-sectional view of the semiconductor device 20 taken along line VV in FIG. FIG. 6 is a cross-sectional view of the semiconductor device 20 taken along line VI-VI in FIG.

Hereinafter, the thickness direction of the wiring board 50 (insulating base material 51) will be referred to as the Z direction. The direction perpendicular to the Z direction and the direction in which the semiconductor elements 40 are arranged is referred to as the X direction. A direction perpendicular to both the Z direction and the X direction is referred to as the Y direction. Unless otherwise specified, the planar shape is the shape viewed from the Z direction, in other words, the shape along the XY plane defined by the X direction and the Y direction. A planar view from the Z direction may be simply referred to as a planar view.

As shown in FIGS. 2 to 6, the semiconductor device 20 includes a sealing resin body 30, a plurality of semiconductor elements 40, a wiring board 50, a plurality of conductive members 60, and a plurality of external connection terminals 70. There is. The semiconductor device 20 of this embodiment constitutes an upper and lower arm circuit 9 for one phase. For example, the inverter 6 is composed of three semiconductor devices 20.

The sealing resin body 30 seals some of the other elements constituting the semiconductor device 20. The remaining parts of the other elements are exposed outside the sealing resin body 30. The sealing resin body 30 is made of, for example, epoxy resin. The sealing resin body 30 is molded, for example, by a transfer molding method. The sealing resin body 30 has a substantially rectangular shape in plan view. The sealing resin body 30 has one surface 30a and a back surface 30b which is the opposite surface to the one surface 30a in the Z direction. One side 30a and back side 30b are, for example, flat surfaces.

The semiconductor element 40 is formed on a semiconductor substrate made of silicon (Si), a wide bandgap semiconductor having a wider bandgap than silicon, or the like. Examples of wide bandgap semiconductors include silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga ₂ O ₃ ), and diamond. The semiconductor element 40 is sometimes referred to as a semiconductor chip.

The element has a vertical structure so that the main current flows in the Z direction. IGBT, MOSFET, diode, etc. can be used as the vertical element. In this embodiment, an IGBT 11 and a diode 12 forming one arm are formed as vertical elements. The vertical element is an RC (Reverse Conducting)-IGBT. The semiconductor element 40 has a gate electrode (not shown). The gate electrode has, for example, a trench structure.

The semiconductor element 40 has main electrodes on both sides in the thickness direction, that is, in the Z direction. Specifically, as a main electrode, a collector electrode 41C is provided on one side facing the wiring board 50, and an emitter electrode 41E is provided on a surface opposite to the surface on which the collector electrode 41C is formed. The collector electrode 41C also serves as the cathode electrode of the diode 12, and the emitter electrode 41E also serves as the anode electrode of the diode 12. The collector electrode 41C corresponds to the first main electrode, and the emitter electrode 41E corresponds to the second main electrode.

The semiconductor element 40 has a substantially rectangular shape in plan view. The collector electrode 41C is formed on almost the entire surface of the semiconductor substrate. The semiconductor element 40 has a pad 41P formed at a different position from the emitter electrode 41E on the back surface. The emitter electrode 41E and the pad 41P are exposed from a protective film (not shown) provided on the back surface of the semiconductor substrate. The emitter electrode 41E is formed on a portion of the back surface of the semiconductor element 40. The pad 41P is a signal electrode. The pads include a gate pad for the IGBT 11 and the like. On the back surface, an emitter electrode 41E is formed at one end in the X direction, and a pad 41P is formed at the other end.

The semiconductor device 20 includes a plurality of semiconductor elements 40 having the configuration described above. The semiconductor device 20 includes, as the semiconductor elements 40, a semiconductor element 40H forming an upper arm 9H and a semiconductor element 40L forming a lower arm 9L. The semiconductor element 40H corresponds to an upper arm element, and the semiconductor element 40L corresponds to a lower arm element. The semiconductor device 20 of this embodiment includes two semiconductor elements 40, one semiconductor element 40H and one semiconductor element 40L.

The semiconductor elements 40H and 40L have the same configuration and are located at substantially the same height in the Z direction. The semiconductor elements 40H and 40L are arranged such that their collector electrodes 41C are on the same side in the Z direction, and their emitter electrodes 41E are on the same side in the Z direction. Semiconductor elements 40H and 40L are arranged side by side in the X direction. In this embodiment, the emitter electrodes 41E are arranged so that their ends facing each other in the X direction face each other.

The wiring board 50 has an insulating base material 51 and metal bodies 52 and 53. The insulating base material 51 is a plate-shaped member made of ceramic. The insulating base material 51 is sometimes referred to as a ceramic substrate. As the ceramic, oxide ceramics and nitride ceramics having good thermal conductivity can be used. More specifically, alumina, aluminum nitride, silicon nitride (silicon nitride), etc. can be used. The insulating base material 51 has a substantially rectangular planar shape.

The wiring board 50 is arranged on one surface side of the semiconductor element 40, that is, on the collector electrode 41C side in the Z direction. The insulating base material 51 has a front surface 51a and a back surface 51b, which is the opposite surface to the front surface 51a in the Z direction, which is the thickness direction of the wiring board 50 (insulating base material 51). A metal body 52 is provided on the front surface 51a of the insulating base material 51, and a metal body 53 is provided on the back surface 51b. The metal body 52 corresponds to the front metal body, and the metal body 53 corresponds to the back metal body.

The metal bodies 52 and 53 are provided as, for example, a metal plate, metal foil, or metal film. In this embodiment, a DBC (Direct Bonded Copper) board is used as the wiring board 50. The metal bodies 52 and 53 are provided as copper (Cu) plates or copper foils. The thickness of the metal bodies 52 and 53 is, for example, about 0.2 mm to 0.8 mm. Each of the metal bodies 52 and 53 is directly bonded to an insulating base material 51 (eg, alumina). The wiring board 50 is a thick copper board to which copper is pasted.

At least a portion of the metal body 52 provides a wiring function. The metal body 52 has a first metal part 521 , a second metal part 522 , a third metal part 523 , and a fourth metal part 524 . Below, they may be simply referred to as metal parts 521, 522, 523, and 524.

A semiconductor element 40H is arranged on the first metal part 521. The first metal portion 521 forms a stacked body with the semiconductor element 40H. The stacking direction of the laminate is approximately parallel to the Z direction. The first metal portion 521 is connected to the collector electrode 41C of the semiconductor element 40H via the bonding member 80. The first metal portion 521 is joined to the collector electrode 41C. The first metal part 521 provides a wiring function.

Similarly, the semiconductor element 40L is arranged on the third metal portion 523. The third metal portion 523 forms a stacked body with the semiconductor element 40L. The third metal portion 523 is connected to the collector electrode 41C of the semiconductor element 40L via the bonding member 80. The third metal portion 523 is joined to the collector electrode 41C. The third metal part 523 provides a wiring function.

The second metal part 522 is joined to the first conductive member 61, which is one of the conductive members 60. The second metal part 522 is also connected to the first conductive member 61 via the joining member 80. The second metal part 522 is soldered to the first conductive member 61. The second metal part 522 of this embodiment is a dummy wiring part that does not provide a wiring function. The second metal part 522 is electrically isolated from the third metal part 523.

The fourth metal portion 524 is joined to a second conductive member 62, which is one of the conductive members 60. The fourth metal portion 524 is also connected to the second conductive member 62 via the joining member 80. The fourth metal part 524 is soldered to the second conductive member 62. The fourth metal part 524 of this embodiment is a dummy wiring part that does not provide a wiring function. The fourth metal part 524 is electrically isolated from the other metal parts 521, 522, and 523.

The joining member 80 is a member that can be joined at a lower temperature than the joining between the metal bodies 52 and 53 and the insulating base material 51. For example, solder or a sintered body of metal such as silver (Ag) or copper can be used. In this embodiment, solder is used as the joining member 80. The first metal part 521 and the third metal part 523 are soldered to the corresponding collector electrode 41C. The second metal part 522 and the fourth metal part 524 are soldered to the corresponding conductive members 60.

For example, as shown in FIG. 3, the surface 51a of the insulating base material 51 includes one first metal portion 521, two second metal portions 522, one third metal portion 523, and two fourth metal portions. 524 is arranged. Each of the metal parts 521, 522, 523, and 524 has a substantially planar shape with the X direction as the longitudinal direction and the Y direction as the lateral direction.

In the Y direction, the first metal part 521 is arranged between two second metal parts 522, and the second metal part 522, first metal part 521, and second metal part 522 are arranged in this order. A predetermined gap is provided between each of the second metal parts 522 and the first metal part 521 for electrical isolation. The first metal portion 521 is provided so as to enclose the semiconductor element 40H in plan view. The lengths of the metal parts 521 and 522 in the X direction are longer than the semiconductor element 40H and are substantially equal to each other. Regarding the length in the Y direction, the first metal part 521 where the semiconductor element 40H is arranged is longer than each of the second metal parts 522.

Similarly, in the X direction, the third metal part 523 is arranged between the two fourth metal parts 524, and the fourth metal part 524, the third metal part 523, and the fourth metal part 524 are arranged in this order. A predetermined gap is provided between each of the fourth metal parts 524 and the third metal part 523 for electrical isolation. The third metal portion 523 is provided so as to enclose the semiconductor element 40L in plan view. The lengths of the metal parts 523 and 524 in the X direction are longer than the semiconductor element 40L and are substantially equal to each other. Regarding the length in the Y direction, the third metal part 523 where the semiconductor element 40L is arranged is longer than each of the fourth metal parts 524.

In this embodiment, the lengths of the metal parts 521 and 523 in the Y direction are substantially equal to each other. Further, the lengths of the metal parts 522 and 524 in the Y direction are substantially equal to each other. The metal parts 521 and 523 are arranged in the X direction. Similarly, the metal parts 522 and 524 are arranged in the X direction. The metal bodies 52 are arranged symmetrically with respect to a virtual center line CL that bisects the insulating base material 51 in the X direction. The length of the metal body 52 in the Z direction, that is, the thickness thereof, is approximately equal within the plane. That is, the thicknesses of the metal parts 521, 522, 523, and 524 are substantially equal to each other.

The metal body 53 is electrically isolated from the metal body 52 by the insulating base material 51. The metal body 53 functions as a heat sink. The planar shape of the metal body 53 is not particularly limited. It may have a planar shape (pattern) different from that of the metal body 52. In this embodiment, the metal body 53 is configured to substantially match the metal body 52 in plan view. The thickness of the metal body 53 is greater than or equal to the thickness of the metal body 52. In this embodiment, the thicknesses of the metal bodies 52 and 53 are approximately equal. The surface of the metal body 53 opposite to the bonding surface with the insulating base material 51 is exposed from the sealing resin body 30 and is substantially flush with the back surface 30b. Since the metal body 53 has the exposed surface 53a, heat can be effectively radiated to the outside of the semiconductor device 20.

The conductive member 60 is formed using a conductive material with excellent electrical conductivity and thermal conductivity in order to provide a wiring function and a heat dissipation (heat transfer) function. In this embodiment, the material is a flat plate made of metal such as copper or copper alloy. The conductive member 60 is connected to the emitter electrode 41E via the bonding member 80. The conductive member 60 is soldered to the emitter electrode 41E. The semiconductor device 20 includes a first conductive member 61 and a second conductive member 62 as the conductive member 60 .

The first conductive member 61 is connected to the emitter electrode 41E of the semiconductor element 40H via a bonding member 80. The first conductive member 61 is bonded to a second metal portion 522, which is a dummy wiring portion, and a third metal portion 523, which provides a wiring function, via a bonding member 80. The first conductive member 61 is soldered to the corresponding emitter electrode 41E, second metal portion 522, and third metal portion 523. The first conductive member 61 functions to transmit heat generated by the semiconductor element 40H to the second metal portion 522. The first conductive member 61 functions to electrically relay the emitter electrode 41E of the semiconductor element 40H and the collector electrode 41C of the semiconductor element 40L.

As shown in FIG. 4, the first conductive member 61 has a substantially rectangular planar shape with the Y direction as the longitudinal direction and the X direction as the lateral direction. In plan view, the first conductive member 61 includes the semiconductor element 40H. In the Y direction, one end of the first conductive member 61 is joined to one of the second metal parts 522, and the other end is joined to another one of the second metal parts 522. The center portion of the first conductive member 61 is joined to the emitter electrode 41E. Further, in the X direction, the first conductive member 61 is arranged so as to straddle the metal parts 521 and 523. In plan view, the first conductive member 61 includes a part of the first metal part 521 including a part where the semiconductor element 40H is arranged, and a part of the third metal part 523 which is closer to the metal part 521 than the part where the semiconductor element 40L is arranged. It is arranged so that it overlaps a part of the In an ideal mounting state, the first conductive member 61 is also line symmetrical with the center line CL as the axis of symmetry.

The second conductive member 62 is connected to the emitter electrode 41E of the semiconductor element 40L via a bonding member 80. The second conductive member 62 is connected to a fourth metal portion 524, which is a dummy wiring portion, via a bonding member 80. The second conductive member 62 is soldered to the corresponding emitter electrode 41E and fourth metal portion 524. The second conductive member 62 functions to transmit heat generated by the semiconductor element 40L to the fourth metal portion 524.

The second conductive member 62 has a main body portion 620 and an extension portion 621. The main body portion 620 is soldered to the emitter electrode 41E and the fourth metal portion 524. Like the first conductive member 61, the main body portion 620 has a generally rectangular planar shape with the Y direction as the longitudinal direction and the X direction as the lateral direction. In plan view, the main body portion 620 includes the semiconductor element 40L. In the Y direction, one end of the main body 620 is joined to one of the fourth metal parts 524, and the other end is joined to another one of the fourth metal parts 524. The center portion of the main body portion 620 is joined to the emitter electrode 41E. Note that, as shown in FIG. 6, the length (thickness) of the first conductive member 61 and the main body portion 620 in the Z direction is thicker than the metal body 52.

The extension portion 621 is a portion extending from the main body portion 620. The extending portion 621 is connected to the main body portion 620 by, for example, joining. The extending portion 621 may be connected to the main body portion 620 by an integral configuration. The main body portion 620 and the extension portion 621 are integrally formed by processing common members. The extension portion 621 electrically relays the main body portion 620 and a negative electrode terminal 70N, which will be described later. As shown in FIGS. 2 and 5, the extending portion 621 of this embodiment crosses the first conductive member 61 in the X direction. The extending portion 621 is arranged to face the first conductive member 61 with a predetermined distance therebetween. The extending portion 621 is connected to the vicinity of the end on the first conductive member 61 side on the surface of the main body portion 620 that is opposite to the bonding surface with the semiconductor element 40L.

The external connection terminal 70 is formed using a metal material such as copper or copper alloy. The external connection terminal 70 includes a positive terminal 70P, a negative terminal 70N, and an output terminal 70A as main terminals connected to the main electrode. The positive terminal 70P is electrically connected to the positive electrode of the smoothing capacitor 5, that is, the P line 7. The positive terminal 70P is sometimes referred to as a high-potential side DC terminal, a high-potential power supply terminal, or a P terminal. The negative terminal 70N is electrically connected to the negative electrode of the smoothing capacitor 5, that is, the N line 8. The negative electrode terminal 70N is sometimes referred to as a low potential side DC terminal, a low potential power supply terminal, or an N terminal. Output terminal 70A is electrically connected to the windings of motor generator 3 via output line 10. The output terminal 70A is sometimes referred to as an AC terminal.

The positive electrode terminal 70P is joined to the first metal portion 521. The positive electrode terminal 70P is electrically connected to the collector electrode 41C of the semiconductor element 40H via the first metal portion 521. The positive electrode terminal 70P of this embodiment extends both inside and outside the sealing resin body 30 in the X direction. The positive electrode terminal 70P protrudes from one side surface 30c of the sealing resin body 30 to the outside. Inside the sealing resin body 30, one end of the positive electrode terminal 70P is bonded to the first metal portion 521 via a bonding member (not shown) such as solder. As shown in FIG. 4, the positive electrode terminal 70P is joined to a portion (one end) of the first metal portion 521 where the first conductive member 61 does not overlap. The other end of the positive electrode terminal 70P is located outside the sealing resin body 30.

The negative electrode terminal 70N is joined to the second conductive member 62. The negative electrode terminal 70N is electrically connected to the emitter electrode 41E of the semiconductor element 40L via the second conductive member 62. The negative electrode terminal 70N of this embodiment extends both inside and outside the sealing resin body 30 in the X direction. The negative electrode terminal 70N is arranged in parallel with the positive electrode terminal 70P in the Y direction, and protrudes to the outside from the same side surface 30c as the positive electrode terminal 70P. By arranging the positive terminal 70P and the negative terminal 70N in parallel, wiring inductance can be reduced. The negative electrode terminal 70N is connected to the second conductive member 62 within the sealing resin body 30. The negative electrode terminal 70N may be connected to the second conductive member 62 by being provided integrally therewith, or may be provided as a separate member and connected to the second conductive member 62 by joining. In this embodiment, one end of the negative electrode terminal 70N is joined to the extending portion 621 of the second conductive member 62 via a joining member (not shown). The other end of the negative electrode terminal 70N is located outside the sealing resin body 30.

The output terminal 70A is electrically connected to the emitter electrode 41E of the semiconductor element 40H and the collector electrode 41C of the semiconductor element 40L. The output terminal 70A of this embodiment extends both inside and outside the sealing resin body 30 in the X direction. The output terminal 70A protrudes to the outside from a side surface 30d opposite to the side surface 30d. Inside the sealing resin body 30, one end of the output terminal 70A is bonded to the third metal portion 523 via a bonding member (not shown). The second conductive member 62 is bonded to a portion (one end) of the output terminal 70A and the third metal portion 523 that does not overlap. The other end of the output terminal 70A is located outside the sealing resin body 30.

The external connection terminal 70 includes a signal terminal 70S connected to the pad 41P of the semiconductor element 40. The signal terminal 70S is electrically connected to the pad 41P via, for example, a bonding wire. The signal terminal 70S is configured on a common lead frame with the positive terminal 70P, the negative terminal 70N, and the output terminal 70A. The semiconductor device 20 of this embodiment includes three signal terminals 70S for one semiconductor element 40. The signal terminal 70S corresponding to the semiconductor element 40H is arranged to sandwich the positive terminal 70P between it and the negative terminal 70N in the Y direction, and protrudes outward from the side surface 30c. The signal terminal 70S corresponding to the semiconductor element 40L is arranged in line with the output terminal 70A in the Y direction, and protrudes to the outside from the side surface 30d.

Note that the external connection terminal may have a bent portion as necessary. For example, when a circuit board on which a control circuit and a drive circuit are formed is arranged above one surface 30a in the Z direction, the signal terminal 70S has a bent part outside the sealing resin body 30, and the signal terminal 70S has a bent part outside the sealing resin body 30, and The tip end side portion extends in the Z direction and is mounted on the circuit board.

<Summary of the first embodiment>
In FIG. 6, the two-dot chain arrow indicates a heat transfer path from the semiconductor element 40L to the wiring board 50. According to the semiconductor device 20 of this embodiment, the heat generated in the semiconductor element 40L by energization is transmitted to the insulating base material 51 made of ceramic through the third metal part 523 joined to the collector electrode 41C. . The third metal part 523 is provided as the metal body 52 of the wiring board 50, and the thermal resistance of the bonding interface between the third metal part 523 and the insulating base material 51 is small.

Further, the heat of the semiconductor element 40L is transmitted to the insulating base material 51 via the second conductive member 62 (conductive member 60) and the fourth metal portion 524 joined to the emitter electrode 41E. The fourth metal part 524 is also provided as the metal body 52, and the thermal resistance of the bonding interface between the fourth metal part 524 and the insulating base material 51 is small. Heat can be radiated from one surface (back surface 30b) of the semiconductor device 20 while radiating heat from the semiconductor element 40L from both surfaces.

The heat transfer path from the semiconductor element 40H to the wiring board 50 is also similar to the heat transfer path of the semiconductor element 40L. Heat generated in the semiconductor element 40H by energization is transmitted to the insulating base material 51 made of ceramic through the first metal part 521 joined to the collector electrode 41C. The first metal part 521 is provided as the metal body 52 of the wiring board 50, and the thermal resistance of the bonding interface between the first metal part 521 and the insulating base material 51 is small.

Further, the heat of the semiconductor element 40H is transmitted to the insulating base material 51 via the first conductive member 61 (conductive member 60), the second metal part 522, and the third metal part 523 joined to the emitter electrode 41E. Ru. The metal parts 522 and 523 are also provided as the metal body 52, and the thermal resistance of the bonding interface between the metal parts 522 and 523 and the insulating base material 51 is small. Heat can be released from one surface (back surface 30b) of the semiconductor device 20 while radiating heat from the semiconductor element 40H from both surfaces. As a result, it is possible to provide a semiconductor device 20 with superior heat dissipation compared to adhesive bonding using a conductive adhesive.

Furthermore, the semiconductor elements 40H and 40L are arranged such that their collector electrodes 41C are on the same side in the Z direction, and their emitter electrodes 41E are on the same side in the Z direction. Therefore, the structure of the semiconductor device 20 can be simplified compared to an inverted configuration. Since the semiconductor elements 40 (40H, 40L) have pads 41P on the same side, electrical connection (for example, wire bonding) to the pads 41P is easy. As a result, the connection structure can be simplified.

In particular, in this embodiment, the metal body 52 including the metal parts 521, 522, 523, and 524 and the insulating base material 51 are directly joined. Since no bonding material is used, the thermal resistance of the bonding interface can be lowered and heat dissipation can be improved.

Furthermore, in this embodiment, the wiring board 50 has a metal body 53 joined to the back surface 51b of the insulating base material 51. Heat from the semiconductor element 40 (40H, 40L) is transferred to the metal body 53 via the insulating base material 51. Therefore, heat dissipation can be improved. Further, by disposing metal on the back surface 51b side, it is possible to suppress warping of the semiconductor device 20. On the surface 51a side of the insulating base material 51, not only the metal body 52 but also the semiconductor element 40 and the conductive member 60 are arranged. Therefore, the metal body 53 may be made thicker than the metal body 52 so as to maintain a balance with the structure on the surface 51a side.

In the wiring board 50 which is a thick copper board, the method of joining the insulating base material 51 and the metal body 52 is not limited to the above-described direct joining. As in a modification shown in FIG. 7, bonding may be performed using a brazing filler metal 54 containing an active metal. FIG. 7 corresponds to FIG. 6. The brazing filler metal 54 is an Ag-based, Cu-based, or Ag-Cu-based bonding material containing an active metal such as titanium (Ti). In FIG. 7 , the metal body 53 is also bonded to the insulating base material 51 with a brazing material 54 . The brazing material 54 is suitable for the insulating base material 51 made of nitride ceramic. By using the brazing filler metal 54, wettability at the bonding interface is improved, and thermal resistance can be reduced. Furthermore, when the metal body 52 is made of aluminum, a molten aluminum bonding method may be used.

In any of the bonding methods, when bonding the insulating base material 51 and the metal body 52 (53) to form a thick copper substrate, a high temperature state is required. For example, in the case of a direct bonding method, heating is required just below the melting point of copper, specifically about 1000 to 1100°C. If the above-mentioned high-temperature bonding is applied to the joints between the collector electrode and the metal body of a semiconductor element, the joint between the emitter electrode and the conductive member, and the joint between the conductive member and the metal body, the temperature will change from the heated state to room temperature. Residual strain due to the temperature difference upon returning acts on the semiconductor element.

In contrast, in this embodiment, a bonding member 80 (for example, solder) that can be bonded at a lower temperature than the bonding that forms the wiring board 50 is used. The joining member 80 can be joined at 200 to 300°C. Therefore, residual strain acting on the semiconductor element 40, that is, element strain, can be reduced. Moreover, since the metal body 52 and the insulating base material 51 are bonded together using a bonding method (for example, a direct bonding method) that forms a thick copper substrate, the thermal resistance can be reduced as described above. Furthermore, connection reliability can be ensured at the joint between the insulating base material 51 (ceramic) and the metal body 52 (53).

Furthermore, in this embodiment, the second metal part 522 is a dummy wiring part that is electrically isolated from the third metal part 523 and does not provide a wiring function. The first conductive member 61 is joined to the metal parts 522 and 523. By intentionally providing the second metal portion 522 that does not provide a wiring function on the surface 51a side of the wiring board 50 where the circuit is formed, the thermal resistance at the bonding interface with the insulating base material 51 is reduced, thereby improving heat dissipation. can be increased.

Furthermore, in this embodiment, the first conductive member 61 is arranged so as to straddle the stack of the first metal part 521 and the semiconductor element 40H in plan view. In the first conductive member 61, a joint part with the semiconductor element 40H (emitter electrode 41E) is located between the joint parts with the two second metal parts 522. Thereby, the heat of the semiconductor element 40H is diffused in the first conductive member 61 in the direction (X direction) orthogonal to the Z direction. Therefore, heat dissipation can be improved. In this embodiment, the arrangement is line symmetrical with respect to the center line CL. Since the symmetry is good, warpage can be suppressed.

Similarly, the second conductive member 62 is arranged so as to straddle the stack of the third metal portion 523 and the semiconductor element 40L in plan view. In the second conductive member 62, a joint portion with the semiconductor element 40L (emitter electrode 41E) is located between the two joint portions with the fourth metal portions 524. Thereby, the heat of the semiconductor element 40L is diffused in the second conductive member 62 in the direction (X direction) orthogonal to the Z direction. Therefore, heat dissipation can be improved. In this embodiment, the arrangement is line symmetrical with respect to the center line CL. Since the symmetry is good, warpage can be suppressed.

The thickness of the conductive member 60 is not limited to the above example. The thickness of the conductive member 60 may be less than or equal to the thickness of the metal body 52. In this embodiment, since the conductive member 60 is thicker than the metal body 52, heat is easily diffused in the conductive member 60 in a direction perpendicular to the Z direction. This also makes it possible to improve heat dissipation. Note that the thickness of the second conductive member 62 is the thickness of the main body portion 620. Further, the linear expansion coefficient of the conductive member 60 may be made different from that of the metal body 52. For example, element strain can be reduced by making the linear expansion coefficient of the conductive member 60 smaller than that of the metal body 52 at least in the Z direction.

The shape of the conductive member 60 is not limited to a flat plate shape. For example, as in a modification shown in FIG. 8, the second conductive member 62 may have a base 63 and convex portions 64a and 64b continuous to the base 63. FIG. 8 corresponds to FIG. 6. The second conductive member 62 is a deformed strip. The protrusions 64a and 64b protrude from the surface of the base 63 on the semiconductor element 40L side. The convex portion 64a is provided at a position overlapping the emitter electrode 41E in a plan view, and the tip of the convex portion 64a is joined to the emitter electrode 41E. The convex portion 64b is provided at a position overlapping the fourth metal portion 524 in plan view, and the tip of the convex portion 64b is joined to the fourth metal portion 524. By providing the convex portion 64a, it becomes easier to connect the signal terminal 70S to the pad 41P of the semiconductor element 40L. By providing the convex portion 64b, the joining member 80 interposed between the second conductive member 62 and the fourth metal portion 524 can be made thinner, and heat dissipation can be improved. A configuration having only one of the protrusions 64a and 64b may be used.

The convex portion 64a may be separated from the base portion 63 as in a modification shown in FIG. Such a convex portion 64a is sometimes called a terminal. FIG. 9 corresponds to FIG. 6. The convex portion 64a is connected to the base portion 63 via a joining member 64c. The same material as the joining member 80 can be used as the joining member 64c. According to this, the same effect as in FIG. 8 can be achieved. Due to the presence of the bonding member 64c, the thermal resistance in the heat transfer path on the emitter side is increased compared to the configuration shown in FIG. 8. The convex portion 64b may be separated from the base portion 63. Note that although FIGS. 8 and 9 show the second conductive member 62 as an example, a similar configuration can be used for the first conductive member 61 as well.

(Second embodiment)
This embodiment is a modification based on the previous embodiment, and the description of the previous embodiment can be used. In the preceding embodiment, the second metal portion 522 was used as a dummy wiring portion. Alternatively, the second metal portion 522 may have a wiring function. In the previous embodiment, the first conductive member 61 was joined to the metal parts 522 and 523. Alternatively, it may be joined only to the second metal portion 522.

FIG. 10 is a plan view showing the wiring board 50 in the semiconductor device 20 of this embodiment, and corresponds to FIG. 3. In FIG. 10, like FIG. 3, the semiconductor element 40 and the bonding member 80 are shown together. However, the description of the bonding member 80 on the emitter electrode 41E of the semiconductor element 40 is omitted for convenience. FIG. 11 is a plan view of the semiconductor device 20 with the sealing resin body 30 and the extension portion 621 omitted, and corresponds to FIG. 4. 12 is a cross-sectional view of the semiconductor device 20 taken along the line XII-XII in FIG. 11, and corresponds to FIG. 5.

The two second metal parts 522 are continuous with the third metal part 523. The integrally constructed metal parts 522 and 523 have a substantially Y-shape. The first conductive member 61 extends in the Y direction, and is joined to each of the second metal parts 522 near both ends. It is then bonded to the emitter electrode 41E of the semiconductor element 40L between the bonding portion with the second metal portion 522. The first conductive member 61 does not overlap the metal parts 523 and 524 in plan view, and does not form a joint with the third metal part 523. The first conductive member 61 is electrically connected to the third metal part 523 via the second metal part 522. The other configurations are the same as those described in the preceding embodiment (see, for example, FIG. 4). Therefore, the effects described in the preceding embodiment can be achieved.

<Summary of the second embodiment>
As described above, the second metal portion 522 is continuous with the third metal portion 523. The first conductive member 61 is bonded only to the second metal portion 522. Thereby, the number of connections between the first conductive member 61 (conductive member 60) and the metal body 52 of the wiring board 50 can be reduced. Specifically, there are four in this embodiment, compared to five in the previous embodiment. Therefore, it is possible to simplify the manufacturing process and reduce costs.

In the preceding embodiment, a current flows from the emitter electrode 41E of the semiconductor element 40H to the third metal portion 523 via the first conductive member 61. In contrast, in this embodiment, a current flows from the emitter electrode 41E of the semiconductor element 40H to each of the two second metal parts 522 via the first conductive member 61. In this way, two current paths are formed. Therefore, wiring inductance can be reduced.

(Third embodiment)
This embodiment is a modification based on the previous embodiment, and the description of the previous embodiment can be used. In the preceding embodiment, the first metal part 521 was provided between the two second metal parts 522 and the third metal part 523 was provided between the two fourth metal parts 524 in the Y direction. On the other hand, the metal body 52 may be arranged differently from the example described above. In the preceding embodiment, the output terminal 70A is provided to extend in the X direction, which is the direction in which the semiconductor elements 40 are arranged, and in the opposite direction to the positive electrode terminal 70P and the negative electrode terminal 70N. On the other hand, the external connection terminals 70 may be arranged differently from the above example. In the preceding embodiment, the second conductive member 62 had the extending portion 621. Instead of this, a configuration may be adopted in which the extension portion 621 is excluded.

FIG. 13 is a plan view of the semiconductor device 20 of this embodiment, with the sealing resin body 30 omitted. The wiring board 50 has one metal portion 521 , 522 , 523 , and 524 as the metal body 52 . The carp wiring board 50 has a configuration in which metal parts 522 and 524 are removed one by one compared to the previous embodiment (see FIG. 4). The first conductive member 61 is joined to the metal parts 522 and 523. The second conductive member 62 is joined to the fourth metal portion 524. The second conductive member 62 does not have the extending portion 621 and only has a portion corresponding to the main body portion 620 described in the preceding embodiment.

The positive electrode terminal 70P has one end joined to the first metal part 521 and extends in the Y direction. The negative electrode terminal 70N is connected to the second conductive member 62 and extends on the same side as the positive electrode terminal 70P in the Y direction. The positive electrode terminal 70P and the negative electrode terminal 70N are arranged side by side in the X direction. As in the previous embodiment, the output terminal 70A is joined to the third metal portion 523 and extends in the X direction.

<Summary of the third embodiment>
With the above-described configuration, as in the configuration described in the preceding embodiment, it is possible to provide the semiconductor device 20 that has high heat dissipation properties and is easy to connect to the pad 41P. Since the positive electrode terminal 70P and the negative electrode terminal 70N are arranged side by side in the X direction, wiring inductance can be reduced. Further, since the extending portion 621 of the second conductive member 62 can be eliminated, the configuration of the conductive member 60 can be simplified. Note that, compared to the second embodiment (see FIG. 11), the metal parts 522 and 524 may be removed one by one, and the positive electrode terminal 70P and the negative electrode terminal 70N may be arranged in the same manner as in FIG. 13.

In the modification shown in FIG. 14, the metal body 52 has two second metal parts 522 and two fourth metal parts 524. One of the second metal parts 522 is arranged in parallel with the first metal part 521 in the Y direction, and the other one is arranged in parallel with the first metal part 521 in the X direction. Similarly, one of the fourth metal parts 524 is arranged in parallel with the third metal part 523 in the Y direction, and the other one is arranged in parallel with the third metal part 523 in the X direction. In the X direction, the second metal part 522, the first metal part 521, the third metal part 523, and the fourth metal part 524 are arranged in this order. The metal parts 522 and 524 arranged in parallel in the Y direction are arranged in the X direction. The first conductive member 61 has a substantially L-shape in plan, is arranged to straddle the stack of the first metal part 521 and the semiconductor element 40H, and is joined to the second metal part 522 near both ends thereof. There is.

The second conductive member 62 does not have the extending portion 621 as in FIG. 13 . The negative electrode terminal 70N is connected to the second conductive member 62. The positive terminal 70P, the negative terminal 70N, and the output terminal 70A extend on the same side in the Y direction. In the X direction, the positive terminal 70P, the negative terminal 70N, and the output terminal 70A are arranged in this order. The configuration in FIG. 14 can also produce the same effects as in FIG. 13. Furthermore, since there are two metal parts 522 and 524 each, heat dissipation can be improved more than the configuration shown in FIG. 13. Note that a configuration may be adopted in which the metal parts 522 and 524 arranged in parallel in the Y direction from FIG. 14 are excluded.

(Fourth embodiment)
This embodiment is a modification based on the previous embodiment, and the description of the previous embodiment can be used. In the preceding embodiment, a metal member was used as the conductive member 60. That is, the conductive member 60 had isotropy in thermal conduction. Instead of this, a conductive member having heat conduction anisotropy may be used.

FIG. 15 is a cross-sectional view showing the semiconductor device 20 of this embodiment, and corresponds to FIG. 6. The semiconductor device 20 includes a second conductive member 62 (conductive member 60) having thermal conduction anisotropy. The main body 620 of the second conductive member 62 is constructed by laminating a plurality of plates 65 made of graphite in the thickness direction and integrating them. The second conductive member 62 is formed, for example, by laminating a plurality of plate materials 65 and then baking them, or by sequentially spraying a gaseous material (graphite material) onto a flat surface.

Graphite has a structure (layered structure) in which carbon atoms form covalent bonds with adjacent carbon atoms in three directions within a plane to form a condensed six-membered ring, and each layer is connected by van der Waals forces. It has anisotropy. Because of this layered structure, the properties are different in the parallel and perpendicular directions to the layers. Specifically, it has high thermal conductivity (approximately 1000 W/mK) in two of the three axes that are orthogonal to each other, that is, the above-mentioned parallel direction, and has high thermal conductivity (about 1000 W/mK) in the remaining one axis direction, that is, the above-mentioned perpendicular direction. It has lower thermal conductivity (approximately 5 to 200 W/mK) than in the parallel direction. That is, it has anisotropy of heat conduction.

The plate material 65 has a rectangular planar shape, and its thickness direction coincides with the above-mentioned vertical direction of the graphite, and the longitudinal direction and the lateral direction of the plane long direction coincide with the above-mentioned parallel direction of the graphite. Therefore, the second conductive member 62 has high thermal conductivity in the X direction and the Y direction.

The main body portion 620 of the second conductive member 62 has a metal layer 66 on the surface of a laminate made of plate materials 65 to improve bondability with the bonding member 80 . The metal layer 66 is formed by a physical deposition method such as sputtering or vapor deposition, or a plating method, and is formed at least on the surface of the stacked body facing the semiconductor element 40L. In this embodiment, in order to improve bondability with the extension portion 621, a metal layer 66 is also formed on the surface opposite to the surface on the semiconductor element 40L side. The metal layer 66 may have a single layer structure or a multilayer structure. The other configurations are the same as those described in the preceding embodiment (see FIG. 6).

Although not shown, the first conductive member 61 also has the same configuration as the main body portion 620. The first conductive member 61 is a surface of a stacked body made of graphite plates 65, and has a metal layer 66 on at least the surface on the semiconductor element 40H side.

<Summary of the fourth embodiment>
The conductive member 60 of this embodiment is arranged so that the thermal conductivity in the direction orthogonal to the Z direction is higher than the thermal conductivity in the Z direction. Thereby, the heat transferred from the emitter electrode 41E side of the semiconductor element 40 can be effectively diffused in a direction perpendicular to the Z direction, that is, in the XY plane. Heat from the semiconductor element 40 spreads from directly above the semiconductor element 40 to a position that does not overlap with the semiconductor element 40. Therefore, heat dissipation can be improved.

The constituent material of the conductive member 60 is not limited to graphite. Any material having heat conduction anisotropy can be used. The conductive member 60 having heat conduction anisotropy can be combined with various configurations shown in the preceding embodiments. The conductive member 60 having heat conduction anisotropy may be applied to either the first conductive member 61 or the second conductive member 62, or to both. The present invention may be applied to the main body portion 620 of the second conductive member 62 having the extending portion 621, or may be applied to the second conductive member 62 not having the extending portion 621.

In the case of the conductive member 60 made of laminated graphite plates 65, the thermal conductivity in the Z direction is lower than the thermal conductivity in the direction perpendicular to the Z direction, as described above. Therefore, as in a modification shown in FIG. 16, a metal column 67 may be provided on the conductive member 60. FIG. 16 corresponds to FIG. 15. The metal column 67 is formed by placing metal in a through hole formed in the plate material 65. The through hole penetrates the laminate of the plate materials 65 in the Z direction. The through hole may have the metal layer 66 as the bottom, or may penetrate the laminate together with the metal layer 66.

The metal fills a considerable amount of the through holes in the laminate. The through hole may be completely filled, or a hollow portion may be provided near the center of the hole. The metal pillar 67 may be formed in advance before mounting the conductive member 60, or may be formed at the time of mounting. In this embodiment, a metal thin film having good wettability with respect to the bonding member 80 is provided on the wall surface of the through hole, and the bonding member 80 (for example, solder) spreads in the through hole to form the metal column 67. There is. The conductive member 60 has a plurality of metal columns 67. A portion of the metal column 67 is formed at a position overlapping the emitter electrode 41E in plan view. Another metal column 67 is formed at a position overlapping with the second metal part 522 or the fourth metal part 524 in plan view.

By providing the metal pillar 67 on the conductive member 60 in this way, the heat diffused in the direction orthogonal to the Z direction can be transmitted in the Z direction by the metal pillar 67. Therefore, heat dissipation through the heat transfer path on the emitter electrode 41E side can be improved.

The arrangement of the conductive member 60 having the graphite plate 65 is not limited to the above example. For example, as in a modified example shown in FIG. 17, a configuration in which a plurality of plate materials 65 are stacked in the X direction may be used. 17 corresponds to the portion of FIG. 4 on the semiconductor element 40L side, and for convenience, the external connection terminal 70 is omitted. In this case, the thermal conductivity is low in the X direction, which is the plate thickness direction, and the thermal conductivity is high in the Y direction and the Z direction. Therefore, the heat of the semiconductor element 40L can be transmitted in the Z direction and the Y direction in the second conductive member 62, and can be transmitted to the fourth metal part 524. Even when applied to the first conductive member 61, the same effect can be achieved.

(Fifth embodiment)
This embodiment is a modification based on the previous embodiment, and the description of the previous embodiment can be used. In the preceding embodiment, a conductive member 60 having anisotropic thermal conductivity was used. Alternatively, a heat pipe may be used.

FIG. 18 is a cross-sectional view showing the semiconductor device 20 of this embodiment, and corresponds to FIG. 6. The semiconductor device 20 includes a second conductive member 62 (conductive member 60). The main body portion 620 of the second conductive member 62 includes a sealed pipe 68 and a liquid 69 disposed within the sealed pipe 68 . Such a second conductive member 62 (main body portion 620) is sometimes referred to as a heat pipe. The closed pipe 68 is a closed container. The closed pipe 68 has an end closed by, for example, welding. The liquid 69 is a liquid that can evaporate (vaporize) and condense (liquefy) in the operating environment, such as water. The other configurations are the same as those described in the preceding embodiment (see FIG. 6). Although not shown, the first conductive member 61 also has the same configuration as the main body portion 620.

<Summary of the fifth embodiment>
The dashed-dotted arrows in FIG. 18 indicate the movement of the liquid 69 and its vapor. According to the conductive member 60 (heat pipe), the temperature of the portion directly above the semiconductor element 40 increases due to the heat of the semiconductor element 40, and the liquid 69 evaporates. At this time, the latent heat of vaporization is absorbed. The vapor moves at a high speed to a portion of the conductive member 60 where the temperature is lower. The conductive member 60 is connected to the metal body 52 of the wiring board 50 via the bonding member 80 . Therefore, in the conductive member 60, the temperature at the joint with the metal body 52 is low.

The vapor condenses at the low temperature section, ie at the junction with the metal body 52. At this time, latent heat of vaporization is released. The heat is transferred to the insulating base material 51 and eventually to the metal body 53 via the joining member 80 and the metal body 52. The condensed liquid 69 is returned directly above the semiconductor element 40 . Therefore, the amount of heat transport can be increased. Thereby, heat dissipation can be improved.

The above-described conductive member 60 can be combined with various configurations shown in the preceding embodiments. The heat pipe may be applied to either the first conductive member 61 or the second conductive member 62, or to both. The present invention may be applied to the main body portion 620 of the second conductive member 62 having the extended portion 621, or may be applied to the second conductive member 62 from which the extended portion 621 is excluded.

(Other embodiments)
The disclosure in this specification, drawings, etc. is not limited to the illustrated embodiments. The disclosure includes the illustrated embodiments and variations thereon by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and/or elements illustrated in the embodiments. The disclosure can be implemented in various combinations. The disclosure may have additional parts that can be added to the embodiments. The disclosure includes those in which parts and/or elements of the embodiments are omitted. The disclosure encompasses any substitutions or combinations of parts and/or elements between one embodiment and other embodiments. The disclosed technical scope is not limited to the description of the embodiments. The technical scope of some of the disclosed technical scopes is indicated by the description of the claims, and should be understood to include equivalent meanings and all changes within the scope of the claims.

The disclosure in the specification, drawings, etc. is not limited by the scope of the claims. The disclosure in the specification, drawings, etc. includes the technical ideas described in the claims, and further extends to a more diverse and broader range of technical ideas than the technical ideas described in the claims. Therefore, various technical ideas can be extracted from the disclosure of the specification, drawings, etc. without being restricted by the claims.

The switching elements that constitute the power conversion circuit (inverter 6) are not limited to the IGBT 11. For example, a MOSFET may be used.

The number of semiconductor elements 40H and 40L is not limited to the above example. A plurality of semiconductor elements 40H may be arranged between the first metal part 521 and the first conductive member 61 and connected in parallel to each other. Similarly, a plurality of semiconductor elements 40L may be arranged between the third metal part 523 and the second conductive member 62 and connected in parallel to each other.

Although a copper-clad board is shown as an example of the wiring board 50, the present invention is not limited thereto. For example, the metal bodies 52 and 53 may be formed by plating, sputtering, vapor deposition, or the like. Although an example of a double-sided substrate having metal bodies 52 and 53 has been shown, the present invention is not limited thereto. The wiring board 50 only needs to have at least the metal body 52. In the case of a configuration in which the metal body 53 is excluded, heat may be radiated from the insulating base material 51 to an external heat exchange section, for example.

Although an example has been shown in which the semiconductor device 20 includes the sealing resin body 30, the present invention is not limited thereto. It is also possible to adopt a configuration in which the sealing resin body 30 is excluded.

The wiring board 50 includes, as the metal body 52, a first metal part 521 to which the semiconductor element 40H is bonded, at least one second metal part 522, and at least one third metal part 523 to which the semiconductor element 40L is bonded. The fourth metal portion 524 may be provided. The first conductive member 61 may be joined to the emitter electrode 41E and the second metal portion 522 of the semiconductor element 40H, and may be electrically connected to the third metal portion 523. The second conductive member 62 may be bonded to the emitter electrode 41E and the fourth metal portion 524 of the semiconductor element 40L.

Although an example has been shown in which the collector electrode 41C is the first main electrode and the emitter electrode 41E is the second main electrode, the present invention is not limited thereto. For example, the emitter electrode 41E may be used as the first main electrode, and the collector electrode 41C may be used as the second main electrode. In this case, the emitter electrode 41E is joined to the corresponding metal parts 521 and 523, and the collector electrode 41C is joined to the corresponding conductive member 60.

1... Drive system, 2... DC power supply, 3... Motor generator, 4... Power converter, 5... Smoothing capacitor, 6... Inverter, 7... P line, 8... N line, 9... Upper and lower arm circuit, 9H... Upper arm , 9L...lower arm, 10...output line, 11...IGBT, 12...diode, 20...semiconductor device, 30...sealing resin body, 30a...one side, 30b...back side, 30c, 30d...side surface, 40, 40H, 40L ... Semiconductor element, 41C... Collector electrode, 41E... Emitter electrode, 41P... Pad, 50... Wiring board, 51... Insulating base material, 51a... Front surface, 51b... Back surface, 52, 53... Metal body, 521... First metal part , 522, 522A, 522B...second metal part, 523...third metal part, 524...fourth metal part, 53a...exposed surface, 54...brazing material, 60...conductive member, 61...first conductive member, 62... 2nd conductive member, 620... Main body part, 621... Extension part, 63... Base, 64a, 64b... Convex part, 64c... Joining member, 65... Plate material, 66... Metal layer, 67... Metal column, 68... Sealed pipe , 69...Liquid, 70...External connection terminal, 70A...Output terminal, 70N...Negative terminal, 70P...Positive terminal, 70S...Signal terminal, 80...Joining member

Claims (10)

A wiring board (50) that is made of ceramic and has an insulating base material (51) having a front surface and a back surface opposite to the front surface in the thickness direction, and a surface metal body (52) provided on the front surface. and,
A first main electrode (41C) provided on a surface opposite to the surface, and a second main electrode (41E) provided on a surface opposite to the opposing surface, forming an upper and lower arm circuit. a plurality of semiconductor elements (40),
a plurality of conductive members (60) joined to the second main electrode;
Equipped with
The plurality of semiconductor elements include an upper arm element (40H) forming an upper arm of the upper and lower arm circuit, and a lower arm element (40L) forming a lower arm,
The surface metal body includes a first metal part (521) joined to the first main electrode of the upper arm element, and at least one second metal part (521) electrically separated from the first metal part. 522), a third metal part (523) joined to the first main electrode of the lower arm element, the first metal part, the second metal part, and the third metal part are electrically connected to each other. at least one separated fourth metal part (524),
The conductive member is joined to the second main electrode and the second metal part of the upper arm element, and also includes a first conductive member (61) electrically connected to the third metal part; a second conductive member (62) joined to the second main electrode and the fourth metal part of the lower arm element;
The second metal part is a dummy wiring part that is electrically isolated from the third metal part and does not provide a wiring function,
In the semiconductor device, the first conductive member is joined to the second metal part and the third metal part of the surface metal body. a first conductive member is arranged to straddle the stack of the first metal part and the upper arm element,
The semiconductor device according to claim 1, wherein the first conductive member is joined to each of the two second metal parts. 3. The semiconductor device according to claim 1, wherein the conductive member is thicker than the surface metal body. 4. The semiconductor device according to claim 1, wherein the surface metal body and the insulating base material are directly bonded. The semiconductor device according to any one of claims 1 to 3, wherein the surface metal body and the insulating base material are joined by a brazing material (54) containing an active metal. 6. The semiconductor device according to claim 1, wherein the wiring board has a back metal body (53 ) provided on the back surface. At least one of the electrically conductive members has heat conduction anisotropy, and is arranged such that the thermal conductivity in a direction perpendicular to the plate thickness direction is higher than the thermal conductivity in the plate thickness direction. The semiconductor device according to any one of claims 1 to 6 . The semiconductor device according to claim 7 , wherein the conductive member includes a plate material (65) made of graphite, and a metal layer (66) provided on a surface of the conductive member on the semiconductor element side. . 9. The semiconductor device according to claim 8 , wherein the conductive member has a metal column (67) in which metal is placed in a through hole formed in the plate material. 7. The semiconductor device according to claim 1, wherein at least one of the conductive members includes a sealed pipe (68) and a liquid (69) disposed within the sealed pipe.

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