JP2002270742A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve durability and reliability by surely radiating heat generated by a semiconductor element. SOLUTION: On the surface 1A of a base plate 1, a projection part 3A is inserted to an opening part 2, and a peripheral part 3B is stuck so as to fit a bus-bar electrode 3. On the surface of the electrode 3, an IGBT 9 and a flow- back diode 12 are soldered via a stress relaxation metal plate 6. Thus, the heat generated by the IGBT 9 is radiated through the projection part 3A of the electrode 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulated gate bipolar transistor
IGBT), MOS transistor (hereinafter, MOS)
The present invention relates to a semiconductor device on which a semiconductor element such as an FET is mounted, and to a semiconductor device suitable for use in, for example, drive control of an electric motor.

[0002]

2. Description of the Related Art Generally, a power module such as an inverter used for motor control is known as a semiconductor device (for example, Japanese Patent Application Laid-Open No. 2000-299419). In such a conventional semiconductor device, a semiconductor element such as an IGBT is mounted on a surface of a ceramic substrate made of, for example, aluminum nitride via a metal foil such as copper or aluminum. Further, a heat radiating plate made of a conductive metal material such as aluminum is attached to the back surface of the ceramic substrate via an oil compound such as silicone grease.

When a semiconductor device operates,
The heat generated by the semiconductor element is transmitted to the heat radiating plate through the ceramic substrate having high thermal conductivity, and the heat from the semiconductor element is radiated.

[0004]

By the way, in the semiconductor device according to the prior art, a heat radiating plate is bonded to the back surface of the ceramic substrate with the silicone grease sandwiched therebetween. In general, an oil compound such as silicone grease has a large thermal resistance, and thus tends to be unable to sufficiently transmit heat generated by a semiconductor element to a heat sink. Further, a gap is easily formed between the ceramic substrate and the heat sink due to warpage of the ceramic substrate or the like, and this gap may increase thermal resistance. As a result, there is a problem that the temperature rise of the semiconductor element cannot be sufficiently suppressed, and the durability and reliability are poor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and it is an object of the present invention to provide a semiconductor device capable of reliably radiating heat generated by a semiconductor element such as an IGBT and improving durability and reliability. It is to provide a device.

[0006]

According to a first aspect of the present invention, there is provided a semiconductor device having a base plate having a penetrating opening, a semiconductor element provided on a front side, and a semiconductor element provided on a back side. A busbar electrode having a projection inserted into the opening of the base plate and having a peripheral edge abutting on the front surface side of the base plate, and bonding the peripheral edge of the rear surface side of the busbar electrode to the surface of the base plate. The present invention is configured such that the protrusion is positioned by cooling with air or water, or the protrusion is bonded to a radiator by using an adhesive.

[0007] With this configuration, the heat generated by the semiconductor element is directly or indirectly transmitted to the bus bar electrode via a stress relaxation metal plate or the like, and is released using the projecting portion of the bus bar electrode. Can be. That is, since there is no silicon grease portion having a large thermal resistance in the middle of the heat radiation path, the overall thermal resistance can be reduced.

Further, since the bus bar electrode is provided with a protruding portion,
The heat capacity of the entire bus bar electrode can be increased. Thus, even when the temperature of the semiconductor element rises transiently, this heat can be absorbed by the bus bar electrode.

Further, since the projecting portion of the bus bar electrode is inserted into the opening of the base plate, the bus bar electrode can be made thicker without largely changing the height of the entire semiconductor device.
For this reason, since the heat flow can be sufficiently diffused in the bus bar electrode having a small thermal resistance, heat can be radiated through the entire outer surface of the bus bar electrode. As a result, the bus bar electrode and the surrounding atmosphere,
The thermal resistance between the cooling water and the radiator can be reduced, and heat radiation can be promoted. Further, since the bus bar electrode is provided with the protruding portion, heat can be radiated not only from the back surface of the protruding portion but also from the side surface, and the heat radiation efficiency can be improved.

Further, since the bus bar electrode and the base plate are joined by bonding the peripheral portion of the bus bar electrode to the base plate, even if a semiconductor element or the like is soldered to the bus bar electrode, even if the bus bar electrode is warped, the bus bar electrode may be bonded. The electrode and the base plate can be securely bonded without causing excessive stress or the like at the bonding portion by solder.

In addition, even if the bottom surface of the bus bar electrode is warped, the overall thermal resistance does not increase since the bottom surface of the bus bar electrode is not connected to the base plate.
Furthermore, since a connection agent is applied to the peripheral portion of the bus bar electrode and adhered by crushing the connection agent, bonding can be performed without any problem even if the flatness of the bottom surface of the bus bar electrode is not sufficiently good.

Further, since the peripheral portion of the bus bar electrode is adhered to the base plate and the bus bar electrode and the base plate are joined, the joint area between them can be reduced as compared with the case where the entire surface is joined. For this reason, even when thermal stress due to a difference in the coefficient of thermal expansion acts between the bus bar electrode and the base plate, the stress due to this thermal stress can be reduced, and these members can be prevented from peeling.

Furthermore, since the joint area between the bus bar electrode and the base plate is small, there is no gap between them due to insufficient flatness or warpage, so that it is possible to prevent an increase in thermal resistance and to prevent separation of the bus bar electrode and the base plate. be able to.

According to a second aspect of the present invention, a semiconductor element is directly mounted on the surface side of the bus bar electrode, or indirectly via a stress relaxation metal plate or a ceramic substrate having a metal thin film on both surfaces. That is, a semiconductor element is mounted.

In this case, the cooling efficiency can be further improved by adopting the water cooling system as compared with the air cooling system. On the other hand, when joining the radiator to the back side of the bus bar electrode, an adhesive having a relatively small thermal resistance can be used, so that the temperature difference at the junction between the bus bar electrode and the radiator is reduced, and the inside of the radiator is reduced. The heat flow can be diffused, and the temperature rise of the semiconductor element can be further suppressed.

A third aspect of the present invention resides in that an insulating region is formed on at least the outer surface of the protruding portion on the back surface of the bus bar electrode.

Thus, even when the projection of the bus bar electrode is exposed and air-cooled, leakage from the outer surface of the projection can be prevented. Also, since the insulating region can keep the protrusion and the outside insulated,
Attach multiple busbar electrodes to the base plate,
Even when a high voltage is applied to the bus bar electrodes, a short circuit between the bus bar electrodes can be prevented.

According to a fourth aspect of the present invention, the bus bar electrode comprises a first metal plate on which a semiconductor element is mounted, and a second metal plate forming the protruding portion, and a back side of the first metal plate. Has a configuration in which the second metal plate is joined directly using solder or an adhesive or indirectly via an insulating substrate.

Thus, the bus bar electrode can be formed by two metal plates, and complicated processing for forming the protruding portion can be omitted. Further, by reducing the thickness of the first metal plate, it is possible to easily transmit X-rays and the like. For this reason, when the first metal plate and the stress relieving metal plate or the like are joined using solder, the presence or absence of a void (gap) at this joint can be confirmed using a method based on X-ray transmission or the like. Furthermore, after mounting the semiconductor element on the first metal plate, the first and second metal plates can be joined. For this reason, after confirming whether or not an abnormality has occurred in the semiconductor element while being mounted on the first metal plate, the first and second metal plates can be joined, and only the normal semiconductor element can be connected to the bus bar. Can be attached to electrodes.

Further, when the first and second metal plates are joined with the insulating substrate interposed therebetween, the first and second metal plates can be insulated from each other, and the first and second metal plates can be insulated. Even when a voltage is applied, it is possible to prevent electric leakage from the second metal plate that radiates heat.

According to a fifth aspect of the present invention, a closed box is provided on the back side of the base plate so as to cover the projecting portion of the bus bar electrode inserted into the opening, and a liquid is accommodated in the closed box to form the bus bar electrode. Liquid cooling or boiling cooling, the outer surface of the closed box is cooled by air cooling or water cooling, or the closed box is joined to a radiator using an adhesive.

Thus, the heat generated by the semiconductor element is
The light can be transmitted into the closed chamber through the protrusion provided on the back surface side of the bus bar electrode, and the heat can be radiated from the outer surface of the closed chamber to the surrounding atmosphere. In addition to the heat capacity of the bus bar electrode, the heat capacity of the liquid in the closed chamber or the latent heat associated with boiling cooling acts, so that even if the temperature changes transiently, it can absorb the temperature change and suppress the temperature rise. it can.

According to a sixth aspect of the present invention, in the radiator, a concave portion is formed at a portion joined to the back surface of the bus bar electrode, and the projecting portion of the bus bar electrode is inserted into the concave portion. is there.

[0024] Thus, the joint area between the bus bar electrode and the radiator can be increased. As a result, the heat flow density between the bus bar electrode and the radiator can be reduced, and the heat flow can be sufficiently diffused into the radiator. Further, the side surface (end surface) of the projecting portion of the bus bar electrode and the side surface of the concave portion of the radiator can be fitted, so that even when a mechanical stress or the like is applied, the bus bar electrode and the radiator are not separated. .

According to a seventh aspect of the present invention, an O-ring is provided between the surface of the base plate and the peripheral portion of the bus bar electrode so as to be located between the side surface of the projecting portion of the bus bar electrode and the adhesive. It is in.

Thus, even when the back surface of the bus bar electrode is water-cooled, the joint between the bus bar electrode and the base plate can be sealed in a liquid-tight manner by the O-ring, and leakage of cooling water can be prevented. .

The invention according to claim 8 is that the projecting portion of the bus bar electrode is formed in a fin shape. Thereby, the surface area (radiation area) of the protrusion can be increased, and the cooling efficiency when the protrusion is air-cooled or water-cooled can be increased. When connecting the bus bar electrode to the radiator,
The joint area between the bus bar electrode and the radiator can be increased, and the joint strength between them can be increased.

According to a ninth aspect of the present invention, a plurality of bus bar electrodes are provided on the base plate. Thus, the size of the entire semiconductor device can be reduced, and a three-phase inverter circuit, an H-bridge circuit, and the like can be formed.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A semiconductor device according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings, taking as an example a case where the present invention is applied to a three-phase inverter circuit.

FIGS. 1 to 3 show a semiconductor device according to a first embodiment. Reference numeral 1 denotes a base plate made of a conductive metal material such as copper or aluminum, and the base plate 1 has a substantially square plate shape. Is formed.
The base plate 1 is provided with, for example, six openings 2 penetrating therethrough.
A bus bar electrode 3 to be described later is provided at a position corresponding to A. The IGBT mounted on these bus bar electrodes 3
9 and the like form the three-phase inverter circuit shown in FIG.

.. Represent the surface 1A of the base plate 1.
The bus bar electrode 3 is formed in a substantially square plate shape using a conductive metal material such as copper similarly to the base plate 1. In addition, the bus bar electrode 3
Is a protruding portion 3A located on the center portion side and having a rear surface side protruding.
And a flange-shaped peripheral portion 3B surrounding the protruding portion 3A and located on the peripheral side. The bus bar electrode 3 has its protruding portion 3A inserted into and fitted into the opening 2 to protrude from the back surface 1B of the base plate 1, and its peripheral portion 3B is located around the opening 2 so that the bus bar electrode 3 It is joined to the surface 1A by the adhesive 4. Here, the adhesive 4 is mixed with particles such as aluminum oxide (alumina) and has high thermal conductivity.

The protruding portion 3A of the bus bar electrode 3 is exposed to the outside air and cooled by air. Thereby, the bus bar electrode 3 is
The heat generated by the IGBT 9, the reflux diode 12, and the like, which will be described later, is released into the outside air through the protrusion 3A.

Reference numeral 5 denotes an insulating region formed on the back surface side of the bus bar electrode 3. The insulating region 5 is formed of an oxide film such as copper or a film of silicon or the like. Is covered over the entire surface.

Reference numerals 6, 6,... Denote a stress relaxation metal plate disposed on the surface side of the bus bar electrode 3. The stress relaxation metal plate 6 is formed of, for example, an alloy of copper and molybdenum. This serves to reduce the thermal stress acting between the bus bar electrode 3 and the like 12. For this reason, the coefficient of thermal expansion of the stress relaxation metal plate 6 is set to an intermediate value between the coefficient of thermal expansion of the IGBT 9 or the like and the coefficient of thermal expansion of the bus bar electrode 3. The stress relaxation metal plate 6 is joined to the center of the bus bar electrode 3 by, for example, solder 7 (eutectic solder) that melts at a relatively low temperature.

Are the arms of a three-phase inverter.
The arm 8 includes an IGBT 9 and a free wheel diode 12 described later provided on the stress relaxation metal plate 6 as semiconductor elements.

9, 9, ... are 1 on the surface of the stress relaxation metal plate 6.
The IGBTs 9 are individually provided, and the IGBTs 9 are joined to the stress relieving metal plate 6 by soldering, for example, using a solder 10 (high-temperature solder) that melts at a relatively high temperature at the back side thereof, and The emitter terminal located on the front side is connected to a free-wheeling diode 12 described later by wire bonding 11. Also, IGB
The gate terminal of T9 is located on the front side of the IGBT 9 and is connected to a drive control circuit (not shown) by wiring or the like.

Reference numerals 12, 12,... Are freewheeling diodes provided one by one on the surface of the stress relaxation metal plate 6 in the vicinity of the IGBT9. The freewheeling diode 12 has a cathode terminal located on the back side thereof. In the same manner as described above, for example, by soldering using a solder 10, the anode terminal located on the front surface side is connected to the emitter terminal of the IGBT 9 by wire bonding 11.

As shown in FIG. 2, three arms 8 of the six arms 8 configured as described above
The collector terminal of T9 and the cathode terminal of the freewheel diode 12 are connected to the P phase of the three-phase inverter circuit through each stress relaxation metal plate 6, and the emitter terminal of the IGBT 9 and the anode terminal of the freewheel diode 12 are connected to the U phase, V phase, Each is connected to the W phase.

The remaining three arms 8 are connected to the collector terminal of the IGBT 9 and the freewheel diode 1 as shown in FIG.
2 cathode terminals through each stress relaxation metal plate 6
The emitter terminal of the IGBT 9 and the anode terminal of the freewheel diode 12 are connected to the V and W phases, respectively.
Connected to the phase. Thereby, the six arms 8 constitute a three-phase inverter circuit.

The semiconductor device according to the present embodiment has the above-described configuration, and its operation will be described.

First, the collector current of the IGBT 9 and the cathode current of the reflux diode 12 flow from the P phase through the stress relaxation metal plate 6. The emitter current of the IGBT 9 and the anode current of the free wheel diode 12 are determined by the wire bonding (not shown) formed on the surface of these elements.
Through the other stress-relief metal plate 6. This allows
The six arms 8 are controlled as three-phase inverters by switching between the ON state and the OFF state of the current to the three-phase induction motor M and the like.

In this embodiment, however, the bus bar electrode 3
Is inserted into the opening 2 on the surface 1A side of the base plate 1 and the peripheral portion 3B is inserted into the surface 1A of the base plate 1.
And the protrusion 3A is air-cooled, so that the heat generated by the IGBT 9 and the reflux diode 12 is indirectly transmitted to the bus bar electrode 3 via the stress relaxation metal plate 6, It can be emitted to the outside using the protrusion 3A of the bus bar electrode 3.

In this case, since the heat generated by the IGBT 9 and the like can be radiated through the protruding portion 3A which is a part of the bus bar electrode 3, it is necessary to provide an oil compound or the like having a large thermal resistance in the middle of the heat radiation path as in the prior art. There is no. Further, since the projecting portion 3A is formed integrally with the bus bar electrode 3, a gap serving as thermal resistance does not occur in the heat radiation path. As a result, the heat resistance in the heat radiation path can be reduced, and the heat can be efficiently radiated.

Further, since the bus bar electrode 3 is provided with the protruding portion 3A, the bus bar electrode 3 is not provided with the protruding portion 3A.
The heat capacity of the entire A can be increased. As a result, even when the temperature of the IGBT 9 or the like transiently rises, this heat can be absorbed by the bus bar electrode 3, and damage to the IGBT 9 or the like due to transient heating can be prevented, and reliability and durability can be improved. .

Further, since the projecting portion 3A of the bus bar electrode 3 is inserted into the opening 2 of the base plate 1, the bus bar electrode 3 can be made thicker without largely changing the height of the entire semiconductor device. For this reason, the heat flow can be sufficiently diffused in the bus bar electrode 3 having a small thermal resistance as indicated by an arrow in FIG. 3, so that heat can be radiated through the entire outer surface of the bus bar electrode 3. As a result, the thermal resistance between the bus bar electrode 3 and the surrounding atmosphere can be reduced, and heat radiation can be promoted. In addition, the projecting portion 3A of the bus bar electrode 3 can emit heat not only from the back surface but also from the side surface, and the heat radiation efficiency can be improved.

Further, since the peripheral portion 3 B of the bus bar electrode 3 is bonded to the base plate 1, the bus bar electrode 3 is joined to the bus bar electrode 3 with the stress relieving metal plate 6 using solder 7.
Even when warpage or the like occurs, the joining between the bus bar electrode 3 and the base plate 1 can be performed reliably and without causing excessive stress or the like at the joint portion by the solder 7. For this reason, peeling of the solder 7 at the joint portion can be prevented, and reliability and durability can be improved.

The peripheral portion 3B of the bus bar electrode 3 is adhered to the base plate 1, and the bus bar electrode 3 and the base plate 1
Therefore, these bonding areas can be made smaller than when bonding is performed over the entire surface. For this reason, even when a thermal stress due to a difference in the coefficient of thermal expansion acts between the bus bar electrode 3 and the base plate 1, the stress due to the thermal stress can be reduced.

Further, the bus bar electrode 3 and the base plate 1
Since the bonding area between them is small, there is no gap between them due to insufficient flatness or warpage, so that it is possible to prevent an increase in thermal resistance and to prevent their separation.

In addition, even when the bottom surface of the bus bar electrode 3 is warped, the overall thermal resistance does not increase because the bottom surface of the bus bar electrode 3 and the base plate 1 are not connected. Further, since the adhesive 4 is applied to the peripheral portion 3B of the bus bar electrode 3 and is crushed and adhered, bonding can be performed without any problem even if the flatness of the bottom surface of the bus bar electrode 3 is not sufficiently good.

Since the insulating region 5 is formed on at least the outer surface of the protruding portion 3A of the back surface of the bus bar electrode 3,
Even when the projecting portion 3A of the bus bar electrode 3 is exposed and air-cooled, it is possible to prevent electric leakage from the outer surface of the projecting portion 3A. In addition, since the insulating region 5 can keep the protruding portion 3A insulated from the outside, a plurality of busbar electrodes 3 are attached to the base plate 1 and a high voltage is applied to the busbar electrodes 3. Also, a short circuit between the bus bar electrodes 3 can be prevented, and the reliability can be improved.

Further, since a plurality of bus bar electrodes 3 are provided on the base plate 1, the whole semiconductor device can be reduced in size and the number of parts can be reduced as compared with the case where a plurality of base plates are used. Cost can be reduced.

In the first embodiment, the projection 3A of the bus bar electrode 3 is air-cooled in the outside air.
A water-cooled radiator 13 for flowing cooling water is attached to the back surface 1B of the base plate 1 as in a first modification shown in FIG.
The protrusion 3A may be configured to be water-cooled.

As described above, by employing the water cooling system as compared with the air cooling system, the cooling efficiency can be further improved.

Further, as in the second modification shown in FIG. 5, a radiator 14 made of copper or the like having a fin-shaped (irregular shape) rear surface is attached to the back surface 1B of the base plate 1, and is attached to the surface of the radiator 14. The back surface of the protruding portion 3A 'of the bus bar electrode 3' may be joined using a high thermal conductive adhesive 15 mixed with particles such as alumina.

As described above, when the radiator 14 is joined to the back surface side of the bus bar electrode 3 ′, the adhesive 15 having a relatively small thermal resistance can be used. The temperature difference in the part can be reduced. Therefore, compared with the case where the protruding portion 3A 'is directly cooled by air or water, the heat generated by the IGBT 9 and the return diode 12 is easily transmitted from the bus bar electrode 3 to the radiator 14, and the heat flow is diffused inside the radiator 14. I can
The temperature rise of the GBT 9 and the like 2 can be further suppressed.

Further, as in the third modification shown in FIG. 6, the bottom surface (back surface) of the projection 3A "of the bus bar electrode 3" may be formed in a fin shape (irregular shape). In addition, when the radiator 16 is attached to the radiator 16 similar to the radiator 14 according to the second modification attached to the back surface 1B of the base plate 1, the radiator 1
6 is provided with a fin-shaped engaging portion 16A having an uneven shape corresponding to the fin-shaped projecting portion 3A ". In a state where the fin engaging portion 16A and the projecting portion 3A" of the bus bar electrode 3 "are engaged with each other. These are joined together using an adhesive 17 having high thermal conductivity.

As a result, the surface area (radiation area) of the projection 3A "can be increased, and the cooling efficiency when the projection 3A" is air-cooled or water-cooled can be increased. When connecting the bus bar electrode 3 ″ to the radiator 16,
The joining area between the bus bar electrode 3 ″ and the radiator 16 can be increased, and the joining strength of these can be increased.

Next, FIG. 7 shows a semiconductor device according to a second embodiment, which is characterized in that the bus bar electrode is formed by joining two metal plates.
In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

Reference numeral 21 denotes a bus bar electrode according to the present embodiment.
The bus bar electrode 21 has a first metal plate 22 formed in a substantially rectangular flat plate shape, and a second metal plate 22 provided on the back surface side of the first metal plate 22 and having a smaller area than the first metal plate 22. And the metal plate 23. Further, the second metal plate 23 has, for example, a thickness dimension larger than that of the first metal plate 22 and is located at the center of the first metal plate 22, and is provided with an adhesive 24 having a high thermal conductivity. The first metal plate 22 is joined to the back surface side.

As a result, the bus bar electrode 21 has a protruding portion 21 A formed by the second metal plate 23, and a peripheral portion 21 B formed by the outer peripheral edge of the first metal plate 22. Then, the second metal plate 2 forming the protrusion 21A
3 is inserted and fitted into the opening 2 of the base plate 1,
The peripheral portion 21B is joined to the surface 1A of the base plate 1 by the adhesive 4.

An insulating region 25 covers the entire outer surface of the second metal plate 22. The insulating region 25 is, like the insulating region 5 according to the first embodiment, an oxide film such as copper or the like. It is formed of a film such as silicon.

Thus, in the present embodiment, the same operation and effect as in the first embodiment can be obtained. However, in the present embodiment, the bus bar electrode 21 is composed of the first metal plate 22 on which the IGBT 9 and the like are mounted and the second metal plate 23 forming the protrusion 21A. As compared with the case where the bus bar electrode 3 is integrally formed, complicated processing for forming the protruding portion 21A can be eliminated, and productivity can be improved.

Further, by reducing the thickness of the first metal plate 22, X-rays and the like can be easily transmitted.
Therefore, when the first metal plate 22 and the stress relieving metal plate 6 and the like are joined by using the solder 7, it is necessary to confirm the presence or absence of a void (gap) in the joint using a method such as X-ray transmission. Can be. As a result, it is possible to use a material having a low void content at the bonding portion, to prevent deterioration of heat radiation due to an increase in voids, and to enhance reliability.

Further, the IGBT is placed on the first metal plate 22.
9. After mounting the freewheel diode 12, the first and second metal plates 22, 23 can be joined. For this reason, after confirming whether or not an abnormality has occurred in the IGBT 9 or the like in a state where the IGBT 9 is mounted on the first metal plate 22, the first and second metal plates 22, 23 can be joined, and a normal IGBT 9 can be joined. And the like can be attached to the bus bar electrode 21 and the yield can be improved.

In the second embodiment, the second metal plate 23 is directly joined to the first metal plate 22 by using the adhesive 24. However, a modification shown in FIG. As described above, the configuration may be such that the insulated substrate 26 is indirectly joined with the insulating substrate 26 interposed between the first and second metal plates 22 and 23. In this case, the first and second metal plates 22 and 23 and the insulating substrate 26 may be joined using an adhesive 27. When a metal thin film or the like is formed on both surfaces of the insulating substrate 26, solder is used. May be joined together.

Thus, the first and second metal plates 22 and 2
3 can be insulated, and even when a high voltage is applied to the first metal plate 22, the second metal plate
3 can be prevented, and reliability can be improved. Further, since it is not necessary to form the insulating region 25 in the second metal plate 23, the manufacturing process can be simplified, and the productivity can be improved.

Next, FIG. 9 shows a semiconductor device according to a third embodiment. The feature of this embodiment is that a closed box is provided on the back side of the base plate to cover the projecting portion of the bus bar electrode. The bus bar electrode is configured to be liquid-cooled or boil-cooled by containing a liquid therein. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

Reference numeral 31 denotes a bus bar electrode according to the present embodiment.
The bus bar electrode 31 is formed by joining the first and second metal plates 32 and 33 using an adhesive 34 in the same manner as the bus bar electrode 21 according to the second embodiment. The bus bar electrode 31 has a protruding portion 31A formed by the second metal plate 33 and a peripheral edge 31B formed by the outer peripheral edge of the first metal plate 32. Then, the second metal plate 33 forming the protruding portion 31A is inserted and fitted into the opening 2 of the base plate 1, and the peripheral portion 31B is
To the surface 1A of the base plate 1.

Reference numeral 35 denotes a closed box attached to the back surface 1B side of the base plate 1. The closed box 35 is provided so as to cover the protruding portion 31A protruding from the opening 2, and contains therein, for example, cooling water, Freon or the like. The liquid 36 is accommodated and constitutes a so-called heat sink. The semiconductor device is a liquid 36
It is used in a state where the back surface 1B of the base plate 1 is located on the upper side so that the base plate 1 can be contacted.

Thus, in the present embodiment, the same operation and effect as in the first embodiment can be obtained. However, in the present embodiment, a closed box 35 is provided on the back surface 1B side of the base plate 1 so as to cover the protruding portion 31A, and the bus bar electrode 31 is liquid-cooled or boil-cooled by storing the liquid 36 inside the closed box 35. IGBT9,
The heat generated by the reflux diode 12 can be transmitted to the liquid 36 in the closed chamber 35 through the protrusion 31A of the bus bar electrode 31. Then, since the heat is radiated to the surrounding atmosphere and the like through the large outer surface of the closed box 35, the heat radiation resistance can be further reduced, and the heat radiation can be promoted. Further, in addition to the heat capacity of the bus bar electrode 31, the heat capacity of the liquid 32 in the closed box 35 or the latent heat associated with the boiling cooling acts, so that even if the temperature changes transiently, the temperature change is absorbed and the temperature rise is reduced. Can be suppressed.

The outer surface of the closed box 35 may be air-cooled or water-cooled. Alternatively, the closed box 35 may be joined to a radiator and cooled by the radiator.

Next, FIG. 10 shows a semiconductor device according to a fourth embodiment. The feature of this embodiment is that a radiator is formed with a recessed portion at a portion joined to the back surface of a bus bar electrode.
The configuration is such that the projection of the bus bar electrode is inserted into the recess. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

Reference numeral 41 denotes a radiator made of a metal material or the like attached to the back surface 1B of the base plate 1.
A fin-shaped heat dissipating portion 41A is formed on the back surface side, and a bottomed concave portion 4 recessed in a substantially square shape at a position corresponding to the protruding portion 3A of the bus bar electrode 3 on the front surface side.
1B is formed. And, the concave portion 4 of the radiator 41
1B, a projection 3A of the bus bar electrode 3 projecting from the back surface 1B of the base plate 1 is inserted and fitted into the projection 1B.
A and the recess 41B are joined by an adhesive 42 having a high thermal conductivity.

Thus, in the present embodiment, the same operation and effect as in the first embodiment can be obtained. However, in the present embodiment, since the radiator 41 is formed with the concave portion 41B and the projecting portion 3A of the bus bar electrode 3 is inserted into the concave portion 41B, the joining between the bus bar electrode 3 and the radiator 41 is performed. The area can be increased. As a result, the heat flow density between the bus bar electrode 3 and the radiator 41 is reduced, and the heat flow can be sufficiently diffused into the radiator 41. Therefore, heat can be radiated through the outer surface of the radiator 41 having a large area, and the heat radiation efficiency can be increased.

Further, the side surface (end surface) of the projecting portion 3A of the bus bar electrode 3 and the side surface of the concave portion 41B of the radiator 41 can be fitted, so that even when a mechanical stress or the like is applied, the bus bar electrode 3 and the The device 41 is not peeled off, and the reliability and durability are improved.

Next, FIG. 11 shows a semiconductor device according to a fifth embodiment. The feature of this embodiment is that the semiconductor device is located between the side surface of the projecting portion of the bus bar electrode and the adhesive so that the surface of the base plate and the surface of the base plate are separated from each other. An O-ring is provided between the busbar electrode and the peripheral edge. In the present embodiment,
The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

Reference numeral 51 denotes an O-ring mounted around the base end of the protruding portion 3A of the bus bar electrode 3;
It is located closer to the protruding portion 3A than the adhesive 4 joining the peripheral portion 3B and the base plate 1, and is disposed between the side surface of the protruding portion 3A and the adhesive 4. And the O-ring 51
The surface 1 of the base plate 1 is formed of an elastic material.
A is elastically deformed by being sandwiched between A and the peripheral portion 3B of the bus bar electrode 3. Thereby, the O-ring 51
Is for sealing between the peripheral portion 3B and the base plate 1.

Thus, in the present embodiment, the same operation and effect as in the first embodiment can be obtained. However, in the present embodiment, since the O-ring 51 is provided between the peripheral portion 3B of the bus bar electrode 3 and the base plate 1, even if the back surface of the bus bar electrode 3 is water-cooled, for example, Connect the O-ring 5 to the joint with the base plate 1.
1 enables a liquid-tight seal and prevents leakage of cooling water.

Next, FIG. 12 shows a semiconductor device according to a sixth embodiment, which is characterized in that an IGBT and a free wheel diode are mounted on the surface of a base plate via a ceramic substrate. . In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

Reference numeral 61 is a flat ceramic substrate formed of a ceramic material such as alumina. The ceramic substrate 61 has a metal thin film 61 on both surfaces thereof.
A, 61A are formed, and these metal thin films 61A are IG
Solder 62 to BT 9, freewheel diode 12, bus bar electrode 3
Respectively.

Thus, in this embodiment, the same operation and effect as in the first embodiment can be obtained.

In the first to fifth embodiments, the IGB is connected to the bus bar electrode 3 via the stress relaxation metal plate 6.
T9, the freewheeling diode 12 is attached. However, as in the sixth embodiment, an IGBT or the like may be attached via a ceramics substrate instead of the stress relaxation metal plate 6, and the IGBT or the like may be directly connected to the bus bar. It may be configured to be soldered to the electrodes and mounted.

In each of the above embodiments, the case where a three-phase inverter is configured as a semiconductor device has been described as an example. However, for example, an H-bridge circuit or the like may be configured.

In each of the above embodiments, the IGBT 9 and the freewheeling diode 12 are used as semiconductor elements. However, a configuration using a MOSFET, a bipolar transistor, or an electrostatic induction transistor (SIT) may be used.

[0085]

As described in detail above, according to the first aspect of the present invention, the projecting portion of the bus bar electrode is inserted into the opening on the front side of the base plate, and the peripheral portion is joined to the surface of the base plate using an adhesive. The projecting portion of the bus bar electrode is cooled by air cooling or the like, or the projecting portion is joined to the radiator by using an adhesive. It can be transmitted indirectly to the bus bar electrode via the bus bar electrode, and can be emitted to the outside using the protrusion of the bus bar electrode.

In this case, the heat generated by the semiconductor element can be dissipated through the protruding portion which is a part of the bus bar electrode, so that there is no need to provide an oil compound or the like having a large thermal resistance in the heat dissipation path as in the prior art. In addition, the heat resistance in the heat radiation path can be reduced, and the heat can be efficiently radiated.

Further, since the bus bar electrode is provided with a protruding portion,
The heat capacity of the entire bus bar electrode can be increased. As a result, even when the temperature of the semiconductor element rises transiently, this heat can be absorbed by the bus bar electrode,
The semiconductor element can be prevented from being damaged by heating, and reliability and durability can be improved.

Further, since the projecting portion of the bus bar electrode is inserted into the opening of the base plate, the bus bar electrode can be made thicker without largely changing the height of the entire semiconductor device.
For this reason, since the heat flow can be sufficiently diffused in the bus bar electrode having a small thermal resistance, heat can be radiated through the entire outer surface of the bus bar electrode. As a result, the bus bar electrode and the surrounding atmosphere,
The thermal resistance between the cooling water and the radiator can be reduced, and heat radiation can be promoted. Further, the projecting portion of the bus bar electrode can emit heat not only from the back surface but also from the side surface, and the heat radiation efficiency can be improved.

Further, since the bus bar electrode and the base plate are joined by bonding the peripheral portion of the bus bar electrode to the base plate, even if the bus bar electrode is warped while the peninsula element or the like is soldered to the bus bar electrode. ,
The connection between the bus bar electrode and the base plate can be performed reliably and without causing an excessive stress or the like at the connection portion by the solder. For this reason, the peeling of the solder at the joint can be prevented, and the reliability and durability can be improved.

Further, since the peripheral portion of the bus bar electrode is adhered to the base plate and the bus bar electrode and the base plate are joined, the joint area can be reduced as compared with the case where the entire surface is joined. For this reason, even when thermal stress due to a difference in the coefficient of thermal expansion acts between the bus bar electrode and the base plate, the stress due to this thermal stress can be reduced, and these members can be prevented from peeling.

Further, since the joint area between the bus bar electrode and the base plate is small, there is no gap between them due to insufficient flatness or warpage, so that it is possible to prevent an increase in thermal resistance and to prevent the separation thereof. be able to.

According to the second aspect of the present invention, a semiconductor element is directly mounted on the surface side of the bus bar electrode, or indirectly via a stress relief metal plate or a ceramic substrate having a metal thin film on both sides. Since the semiconductor element is mounted on the substrate, the cooling efficiency can be further improved by adopting the water cooling system as compared with the air cooling system. On the other hand, when joining a radiator to the back side of the bus bar electrode,
Since an adhesive having a relatively small thermal resistance can be used, the temperature difference at the junction between the bus bar electrode and the radiator can be reduced, the heat flow can be diffused inside the radiator, and the temperature of the semiconductor element can be further increased. Can be suppressed.

According to the third aspect of the present invention, since the insulating region is formed on at least the outer surface of the protruding portion on the back surface of the bus bar electrode, even when the protruding portion of the bus bar electrode is exposed and air-cooled, Electric leakage from the outer surface of the protrusion can be prevented. Further, since the insulating region can keep the protruding portion and the outside insulated from each other, a plurality of busbar electrodes can be attached to the base plate, and even when a high voltage is applied to the busbar electrodes, the busbar electrodes can be maintained. Short circuit between each other can be prevented.

According to the fourth aspect of the present invention, the bus bar electrode has the first metal plate on which the semiconductor element is mounted and the second metal plate forming the projecting portion.
, And on the back side of the first metal plate,
Since the second metal plate is joined directly using solder or adhesive or indirectly via an insulating substrate, the bus bar electrode can be formed by two metal plates, and the projecting portion can be formed. Can eliminate complicated processing for forming
Productivity can be improved.

Further, by reducing the thickness of the first metal plate, X-rays and the like can be easily transmitted. For this reason, when the first metal plate and the stress relieving metal plate or the like are joined using solder, the presence or absence of a void (gap) at this joint can be confirmed using a method based on X-ray transmission or the like.
As a result, it is possible to use a material having a low content of voids in the joint portion, prevent deterioration of heat dissipation due to an increase in voids, and improve reliability.

Furthermore, after mounting the semiconductor element on the first metal plate, the first and second metal plates can be joined. For this reason, after confirming whether or not an abnormality has occurred in the semiconductor element while being mounted on the first metal plate, the first and second metal plates can be joined, and only the normal semiconductor element can be connected to the bus bar. It can be attached to the electrode, and the yield can be improved.

When the first and second metal plates are joined with the insulating substrate interposed therebetween, the first and second metal plates can be insulated from each other, and the first and second metal plates can be insulated. Even when a voltage is applied, it is possible to prevent electric leakage from the second metal plate that radiates heat.

According to the fifth aspect of the present invention, a closed box is provided on the back surface side of the base plate to cover the projecting portion of the bus bar electrode inserted into the opening, and the liquid is stored in the closed box. Liquid or boil the busbar electrode,
Because the outer surface of the closed box was air-cooled or water-cooled, or the closed box was bonded to a radiator using an adhesive,
The heat generated by the semiconductor element can be transmitted into the closed chamber through the protrusion provided on the back surface side of the bus bar electrode, and can be radiated from the outer surface of the closed chamber to the surrounding atmosphere. In addition to the heat capacity of the bus bar electrode, the heat capacity of the liquid in the closed chamber or the latent heat associated with boiling cooling acts, so that even if the temperature changes transiently, it can absorb the temperature change and suppress the temperature rise. it can.

According to the sixth aspect of the present invention, the radiator has a configuration in which a recessed portion is formed at a portion joined to the back surface of the bus bar electrode, and the projection of the bus bar electrode is inserted into the recessed portion. Therefore, the joint area between the bus bar electrode and the radiator can be increased. As a result, the heat flow density between the bus bar electrode and the radiator can be reduced, and the heat flow can be sufficiently diffused into the radiator. Therefore, heat can be radiated through the outer surface of the radiator having a large area, and the heat radiation efficiency can be increased. Further, the side surface (end surface) of the projecting portion of the bus bar electrode and the side surface of the concave portion of the radiator can be fitted, so that even when a mechanical stress or the like is applied, the bus bar electrode and the radiator are not separated. .

According to the seventh aspect of the present invention, an O-ring is provided between the surface of the base plate and the peripheral portion of the bus bar electrode, between the side surface of the projecting portion of the bus bar electrode and the adhesive. Therefore, even when the back side of the bus bar electrode is water-cooled, the joint between the bus bar electrode and the base plate can be sealed in a liquid-tight manner by the O-ring,
Leakage of cooling water can be prevented.

According to the eighth aspect of the present invention, since the projecting portion of the bus bar electrode is formed in a fin shape, the surface area (radiation area) of the projecting portion can be increased, and cooling when the projecting portion is air-cooled or water-cooled. Efficiency can be increased. Also,
When connecting the bus bar electrode to the radiator, the joining area between the bus bar electrode and the radiator can be increased, and the joining strength between them can be increased.

According to the ninth aspect of the present invention, since a plurality of bus bar electrodes are provided on the base plate, the entire semiconductor device can be reduced in size, and a three-phase inverter circuit, an H-bridge circuit and the like can be formed. be able to.

[Brief description of the drawings]

FIG. 1 is a plan view showing a semiconductor device according to a first embodiment of the present invention.

FIG. 2 illustrates a semiconductor device according to the first embodiment;
It is an electric circuit diagram showing a phase inverter.

FIG. 3 is a cross-sectional view of the semiconductor device as viewed from a direction indicated by arrows III-III in FIG. 1;

FIG. 4 is a cross-sectional view illustrating a semiconductor device according to a first modification of the first embodiment.

FIG. 5 is a sectional view showing a semiconductor device according to a second modification of the first embodiment.

FIG. 6 is a cross-sectional view illustrating a semiconductor device according to a third modification of the first embodiment.

FIG. 7 is a sectional view showing a semiconductor device according to a second embodiment;

FIG. 8 is a sectional view showing a semiconductor device according to a modification of the second embodiment.

FIG. 9 is a sectional view showing a semiconductor device according to a third embodiment.

FIG. 10 is a sectional view showing a semiconductor device according to a fourth embodiment.

FIG. 11 is a sectional view showing a semiconductor device according to a fifth embodiment;

FIG. 12 is a sectional view showing a semiconductor device according to a sixth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base plate 2 Opening 3,3 ', 3 ", 21,31 Bus bar electrode 3A, 3A', 3A", 21A, 31A Projecting part 3B, 3B ', 3B ", 21B, 31B Peripheral part 5,25 Insulating area 6 Stress relaxation metal plate 9 IGBT (semiconductor element) 12 circulating diode (semiconductor element) 13 water-cooled radiator 14, 16, 41 radiator 22, 32 first metal plate 23, 33 second metal plate 26 insulating substrate 35 closed chamber 41B Recess 51 O-ring 61 Ceramic substrate

Claims (9)

[Claims] 1. A base plate having a penetrating opening, and a peripheral edge provided with a semiconductor element on the front side and having a projecting part inserted into the opening of the base plate on the back side and contacting the front side of the base plate. A bus bar electrode having a portion, the peripheral portion of the back side of the bus bar electrode is bonded to the surface of the base plate using an adhesive, and the protrusion located on the back side of the bus bar electrode is air-cooled or water-cooled. A semiconductor device having a configuration in which the projection is cooled or bonded to the radiator by using an adhesive. 2. The semiconductor element is directly mounted on the surface side of the bus bar electrode, or the semiconductor element is mounted indirectly via a stress relieving metal plate or a ceramic substrate having a metal thin film on both surfaces. The semiconductor device according to claim 1, wherein 3. The semiconductor device according to claim 1, wherein an insulating region is formed on at least an outer surface of said projecting portion on a back surface of said bus bar electrode. 4. The bus bar electrode includes a first metal plate on which the semiconductor element is mounted, and a second metal plate forming the protruding portion, and a back surface of the first metal plate includes: 4. The semiconductor device according to claim 1, wherein the second metal plate is bonded directly using solder or an adhesive or indirectly via an insulating substrate. 5. 5. A closed box is provided on the back side of the base plate to cover the projecting portion of the bus bar electrode inserted into the opening, and a liquid is accommodated in the closed box so that the bus bar electrode is liquid. 5. The structure according to claim 1, wherein the enclosure is cooled by cooling or boiling, the outer surface of the enclosure is cooled by air or water, or the enclosure is joined to a radiator using an adhesive. Semiconductor device. 6. The radiator has a configuration in which a recessed portion is formed at a portion joined to the back surface of the bus bar electrode, and a projection of the bus bar electrode is inserted into the recessed portion. , 4 or 5. 7. An O-ring is provided between a surface of the base plate and a peripheral portion of the bus bar electrode, which is located between a side surface of the projecting portion of the bus bar electrode and the adhesive. 7. The semiconductor device according to 1, 2, 3, 4, 5, or 6. 8. The semiconductor device according to claim 1, wherein said projecting portion of said bus bar electrode is formed in a fin shape. 9. The system according to claim 1, wherein a plurality of bus bar electrodes are provided on said base plate.
9. The semiconductor device according to 6, 7, or 8.