JPH09102578A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an internal inductance by connecting the emitter of a first chip to an output bus bar, connecting the cathode of a second diode to the output bus bar, connecting the collector of a second chip to a negative bus bar, and connecting the cathode of a first diode to the negative bus bar. SOLUTION: A 1-GBT chip 30A having a collector connected and a diode 42A having anode connected are fixed on a positive bus bar 20. A 1-GBT chip 32A having a collector connected and a diode 40A having an anode connected are fixed on an output bus bar 22. The 1-GBT chip 30A is connected at its emitter with the output bus bar 22, and the diode 42A is connected at its cathode with the output bus bar 22. Fixed on the 1-GBT chip 30A and diode 42A through insulators 60A to 60F is a negative bus bar 24 which is parallel to the positive bus bar 20. The 1-GBT chip 32A is connected at its collector to the negative bus bar 24, and the diode 40A is connected at its cathode to the negative bus bar 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device that switches a large current at high speed, and more particularly to a semiconductor device suitable for use in an electric vehicle drive device or a vehicle-mounted motor control device.

[0002]

2. Description of the Related Art In electric vehicles, especially electric vehicles, there is a demand for reduction in size and weight of drive devices. In such a drive,
A semiconductor device that switches a large current at high speed is used in order to obtain an alternating current for driving a motor from a direct current power source such as a battery. In particular, due to recent advances in power electronics, IGBTs (Insulated G
As high-speed and high-power semiconductors such as an ATE Bipolar Transistor are being developed, it is important to reduce the internal inductance in order to reduce the loss generated.

Therefore, as described in, for example, Japanese Patent Publication No. 5-25392, a magnetic field is generated by making a conducting path leading to a collector of a transistor and a conducting path reaching an emitter close to each other in parallel. It is known to cancel and reduce the inductance.

Further, for example, as disclosed in Japanese Patent Laid-Open No. 6-69415, a two-circuit built-in system is known in which a series circuit of a transistor and a diode is arranged in parallel.
Also in such a two-circuit built-in system, it is known that the conducting path leading to the collector of the transistor and the conducting path reaching the emitter are closely parallel to each other to reduce the inductance.

[0005]

However, in the two-circuit built-in system, since the jumper plate is used to connect the first circuit and the second circuit, the inductance increases due to this jumper plate. There was a problem that.

An object of the present invention is to provide a semiconductor device of a two-circuit built-in type having a small internal inductance.

[0007]

In order to achieve the above object, the present invention provides a first circuit comprising a series circuit of a first IGBT chip and a first diode, a second IGBT chip and a second circuit. In a semiconductor device in which a second circuit composed of a series circuit of diodes is arranged in parallel, a positive busbar fixed on an insulating substrate, and an output busbar arranged in parallel with the positive busbar and fixed on the insulating substrate. A first IGBT chip fixed to the positive electrode bus bar and having a collector connected thereto, and a second diode fixed to the positive electrode bus bar and having an anode connected thereto, The second IGBT chip fixed to the output busbar and having its collector connected, and the second IGBT chip fixed to the output busbar. The first in which the anode is connected
A diode, a first connecting conductor connecting the emitter of the first IGBT chip and the output busbar, a second connecting conductor connecting the cathode of the second diode and the output busbar, and the first connecting conductor. Above the IGBT chip and the second diode, a negative electrode bus bar fixed in parallel with the positive electrode bus bar via an insulator, and a third collector connecting the collector of the second IGBT chip and the negative electrode bus bar. The connection conductor and the fourth connection conductor that connects the cathode of the first diode and the negative bus bar are provided. With such a configuration, the inductance can be reduced.

In the above semiconductor device, preferably, the third and fourth connection conductors are provided for the first and second connection conductors.
In this configuration, the connecting conductors are arranged in parallel and close to each other. With such a configuration, magnetic field canceling can reduce the inductance.

In the above semiconductor device, preferably, the first diode fixed on the output bus bar is arranged in proximity to the first IGBT chip fixed on the positive electrode bus bar, The second IGBT chip fixed on the output bus bar is arranged in proximity to the second diode fixed on the positive electrode bus bar, and magnetic field canceling by an alternating current component is performed. It will be possible.

In the above semiconductor device, preferably, the first series circuit and the second series circuit are symmetrically arranged, while the positive bus bar, the negative bus bar and the output bus bar are symmetrically arranged. The current distribution can be made uniform.

The above semiconductor device preferably further comprises a case fixed to the insulating plate, and a part of the negative electrode bus bar is held by the case. With such a structure, It becomes possible to firmly hold the negative electrode bus bar.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. 1 is a plan view of a semiconductor device according to an embodiment of the present invention.
3 is a sectional view taken along line XX of FIG. 1, and FIG. 3 is a circuit diagram of a semiconductor device according to an embodiment of the present invention.

In FIG. 1, a rectangular frame-shaped case 12 is fixed on a rectangular insulating plate 10. The insulating plate 10 is made of, for example, an aluminum nitride plate. Insulating plate 10
A positive electrode bus bar 20 used as a rectangular positive electrode terminal is joined to the upper side of the drawing on the left side of the drawing. A brazing material such as silver brazing is used for joining. The insulating plate 1 is on the right side of the positive electrode bus bar 20.
Above 0 is an output busbar 2 used as an output terminal.
2 are joined by brazing. Positive bus bar 2
0 and the output busbar 22 are mounted on the same insulating plate 10 and thus are parallel to each other. Further, the long axis direction of the rectangular positive electrode bus bar 20 and the long axis direction of the output bus bar 22 are parallel to each other, and in this respect also, the positive electrode bus bar 20 and the output bus bar 22 are parallel to each other.

On the positive electrode bus bar 20, solder I (not shown) for switching, which is a power module, is used.
GBT chips 30A and 30B and commutation diode 42
A and 42B are fixed. Therefore, in terms of an electric circuit, the collectors of the IGBT chips 30A and 30B and the anodes of the diodes 42A and 42B are connected to the positive busbar 20.

Here, assuming that the current capacity of each of the IGBT chips 30A and 30B is 100A, in order to set the current capacity of the entire power module to 200A, the IGBT chips are
The chip 30A and the IGBT chip 30B are connected in parallel with each other. Therefore, when the current capacity of the entire power module may be 100 A, only the IGBT chip 30A may be used.

On the output bus bar 22, IGBT chips 32A, 32B for switching which are power modules and diodes 40A, 40B for commutation are fixed by solder (not shown). Therefore, in terms of electric circuit, the collectors of the IGBT chips 32A and 32B and the anodes of the diodes 40A and 40B are connected to the output bus bar 2
2 are connected.

Here, assuming that the current capacity of each of the IGBT chips 32A and 32B is 100A, in order to set the current capacity of the entire power module to 200A, the IGBT is
The chip 32A and the IGBT chip 32B are connected in parallel with each other. Therefore, when the current capacity of the entire power module may be 100 A, only the IGBT chip 30A may be used.

The output bus bar 22 is formed integrally with the connection terminal portions 22x1, 22x2, 22x3, 2 having an uneven shape.
2 × 4, the emitter of the IGBT chip 30A is connected to the output busbar 22 by the aluminum wire 50A1.
Connected to the connection terminal portion 22x2 of the IGBT chip 30
The B emitter is connected to the connection terminal portion 22x3 of the output busbar 22 by an aluminum wire 50A2.
The cathode of the diode 42B is connected to the aluminum wire 5
0A4 allows connection terminal 22x1 of output busbar 22
The cathode of the diode 42A is connected to the connection terminal 2 of the output busbar 22 by the aluminum wire 50A3.
It is connected to 2x1. Here, aluminum wire 50A
Each of 1,50A2, 50A3, and 50A4 is represented by two lines, but in reality, a plurality of lines are used in parallel. Aluminum wire 50A1, 50A2, 50A
Since 3,50A4 are provided by wire bonding, the diameter of one wire is limited, and a plurality of wires are used according to the magnitude of the current flowing from the IGBT chip or the diode.

On the positive electrode bus bar 20, three cylindrical insulators 60A, 60B and 60C are fixed. Further, three cylindrical insulators 60D, 60E, 60F are fixed on the output bus bar 22. And
6 insulators 60A, 60B, 60C, 60D, 60
The negative electrode bus bar 24 is fixed on E and 60F. Therefore, the negative electrode bus bar 24 and the positive electrode bus bar 20 are parallel to each other, and the directions of the currents flowing through the negative electrode bus bar 24 and the positive electrode bus bar 20 are opposite to each other. The negative electrode bus bar 24 is also held by the case 12.

On the right side of the negative electrode bus bar 24, there are integrally formed concavo-convex connection terminal portions 24x1, 24x2, 24.
x3, 24x4, the emitter of the IGBT chip 32A is connected to the connection terminal portion 24x2 of the negative busbar 24 by the aluminum wire 50B1, and the emitter of the IGBT chip 32B is connected to the negative busbar 24 by the aluminum wire 50B2. It is connected to the terminal portion 24x3. The cathode of the diode 40A is connected to the connection terminal 24x1 of the negative busbar 24 by the aluminum wire 50B3, and the cathode of the diode 40B is
It is connected to the connection terminal 24x1 of the negative electrode bus bar 24 by an aluminum wire 50B3. Here, each of the aluminum wires 50B1, 50B2, 50B3, and 50B4 is represented by two lines, but in reality, a plurality of aluminum wires are used in parallel. Aluminum wire 50B1, 50B
Since 2,50B3 and 50B4 are provided by wire bonding, the diameter of one wire is limited,
A plurality of IGBT chips or diodes are used depending on the magnitude of the current flowing from them.

Here, the aluminum wires 50A1 and 50A
2,50A3,50A4 and aluminum wire 50B1,50
B2, 50B3, and 50B4 are kept parallel to each other. That is, although this point will be described in detail with reference to FIG. 2, the aluminum wire 50A1 and the aluminum wire 50B1 are
Are parallel to each other, and the flowing current directions are opposite to each other, and the aluminum wires 50A2 and 50B2 are parallel to each other, and the flowing current directions are opposite to each other. Further, the aluminum wire 50A3 and the aluminum wire 50B3 are parallel to each other, and the flowing current directions are opposite to each other, and the aluminum wire 50A4 and the aluminum wire 50B4 are
They are parallel to each other, and the directions of flowing currents are opposite to each other.

Therefore, the emitter of the IGBT chip 30A is connected to the anode of the diode 40A to form a first series circuit. Further, the emitter of the IGBT chip 30B is connected to the anode of the diode 40B,
This also constitutes the first series circuit. The series circuit of the IGBT chip 30A and the diode 40A is connected in parallel with the series circuit of the IGBT chip 30B and the diode 40B. The current capacity of the series circuit of the IGBT chip 30A and the diode 40A is 100 A, and the IGBT chip 3
0B and diode 40B series circuit current capacity 100
Assuming A, these circuits are connected in parallel, and the current capacity is 200A. Therefore, the current capacity is 100
When A is sufficient, IGBT chip 30A and diode 4
Only a 0A series circuit need be used.

The emitter of the IGBT chip 32A is connected to the anode of the diode 42A to form a second series circuit. The emitter of the IGBT chip 32B is connected to the anode of the diode 42B,
This also constitutes the second series circuit. The series circuit of the IGBT chip 32A and the diode 42A is connected in parallel to the series circuit of the IGBT chip 32B and the diode 42B. The current capacity of the series circuit of the IGBT chip 32A and the diode 42A is 100A, and the IGBT chip 3
Set the current capacity of the series circuit of 2B and diode 42B to 100.
Assuming A, these circuits are connected in parallel, and the current capacity is 200A. Therefore, the current capacity is 100
When A is sufficient, IGBT chip 32A and diode 4
Only a 2A series circuit need be used.

The first series circuit and the second series circuit are connected in parallel to the positive bus bar 20 and the negative bus bar 24, respectively, and the IGBT of the first series circuit is connected.
The connection point between the chip emitter and the diode anode, and the diode cathode and the IGBT in the second series circuit.
The connection points of the chip collectors are commonly connected to the output bus bar 22.

A terminal block 70 is attached to the left side of the positive electrode bus bar 20 and on the insulating plate 10. Gate resistors 74A and 74B are fixed on the terminal block 70 by soldering. Gate resistance 74A
Is an IGBT chip 30A with an aluminum wire 78A1.
Connected to the base. The gate resistor 74B is connected to the base of the IGBT chip 30B by an aluminum wire 78B1. A terminal block 72 is mounted on the insulating plate 10 on the right side of the output bus bar 22. Gate resistors 76A and 76B are fixed on the terminal block 72 by soldering. Gate resistance 76A
Is an IGBT chip 32A with an aluminum wire 78A2.
Connected to the base. The gate resistor 76B is connected to the base of the IGBT chip 32B by an aluminum wire 78B2.

Heat is dissipated from the IGBT chip by the insulating plate 10.
Done through.

Next, the sectional structure of the semiconductor device according to the embodiment of the present invention shown in FIG. 1 will be described with reference to FIG.

A frame-shaped case 12 is fixed on the insulating plate 10. A positive electrode bus bar 20 used as a positive electrode terminal is joined to the left side of the insulating plate 10 in the drawing. A brazing material such as silver brazing is used for joining. On the right side of the positive bus bar 20 and on the insulating plate 10, an output bus bar 22 used as an output terminal is joined by brazing. The positive bus bar 20 and the output bus bar 22 are mounted on the same insulating plate 10, and thus are parallel to each other. Further, the long axis direction of the positive electrode bus bar 20 (direction orthogonal to the drawing) and the long axis direction of the output bus bar 22 (direction orthogonal to the drawing) are parallel to each other. , Parallel to each other.

On the positive electrode bus bar 20, a switching IGBT, which is a power module, is connected by solder 80.
The chip 30A and a diode for commutation (not shown) are fixed. Therefore, in terms of electric circuit, the IGBT chip 3
The collector of 0 A and the anode of the diode are connected to the positive bus bar 20.

Further, the solder 8 is placed on the output bus bar 22.
2, I for switching which is a power module
The GBT chip 32A and a diode for commutation (not shown) are fixed. Therefore, in terms of an electric circuit, the collector of the IGBT chip 32A and the anode of the diode are connected to the output bus bar 22.

The output bus bar 22 has an integrally formed concavo-convex connection terminal portion 22x2, and the emitter of the IGBT chip 30A is connected to the connection terminal portion 22x2 of the output bus bar 22 by an aluminum wire 50A1. ing. The cathode of the diode (not shown) is connected to the connection terminal of the output bus bar 22 by an aluminum wire. Here, a plurality of aluminum wires 50A1 are used in parallel. Since the aluminum wire 50A1 is provided by wire bonding, the diameter of one wire is limited, and a plurality of aluminum wires 50A1 are used according to the magnitude of the current flowing from the IGBT chip or the diode.

A cylindrical insulator 60B is fixed on the positive electrode bus bar 20. A cylindrical insulator 60E is fixed on the output bus bar 22. The negative electrode bus bar 24 is fixed on the insulators 60B and 60E. Therefore, the negative bus bar 2
4 is parallel to the positive electrode bus bar 20 and the directions of the currents flowing through the negative electrode bus bar 24 and the positive electrode bus bar 20 are opposite to each other.

On the right side of the negative electrode bus bar 24, there is an integrally formed concavo-convex connecting terminal portion 24x2,
The emitter of the GBT chip 32A is an aluminum wire 50B.
1 is connected to the connection terminal portion 24x2 of the negative busbar 24. The cathode of the diode (not shown) is connected to the connection terminal of the negative bus bar 24 by an aluminum wire. Here, aluminum wire 50B1
Used in parallel. Aluminum wire 50B1
Since the wire is provided by wire bonding, the diameter of one wire is limited, and a plurality of wires are used according to the magnitude of the current flowing from the IGBT chip or the diode.

The negative electrode bus bar 24 is made of an insulator 60.
Since the positive electrode bus bar 20 and the output bus bar 22 are supported on different planes via B and 60E, there is a step between the negative electrode bus bar 24 and the emitter of the IGBT chip 32A, which is a conventional wire bonding technique. Then
If there is such a step, it was impossible to bond with aluminum wire, but in recent years, a bonding technology that can be applied to such a step has been developed, and such an arrangement is possible. Has become. Further, since the cylindrical insulators 60B and 60E are used between the positive electrode bus bar 20 and the negative electrode bus bar 24, it is possible to prevent a resonance phenomenon during ultrasonic bonding.

Here, the aluminum wire 50A1 and the aluminum wire 50B1 are kept parallel to each other. That is, the aluminum wire 50A1 and the aluminum wire 50B1 are
They are parallel to each other, and the directions of flowing currents are opposite to each other.

Therefore, the emitter of the IGBT chip 30A is connected to the anode of a diode (not shown) fixed on the output bus bar 22 to form a first series circuit. Further, the emitter of the IGBT chip 32A is connected to the anode of a diode (not shown) fixed on the positive electrode bus bar 20 to form a second series circuit.

The first series circuit and the second series circuit are connected in parallel to the positive bus bar 20 and the negative bus bar 24, respectively, and the IGBT of the first series circuit is connected.
The connection point between the chip emitter and the diode anode, and the diode cathode and the IGBT in the second series circuit.
The connection points of the chip collectors are commonly connected to the output bus bar 22.

Further, a terminal block 70 is attached on the left side of the positive electrode bus bar 20 and on the insulating plate 10. A gate resistor 74A is fixed on the terminal block 70 by soldering. The gate resistor 74A is connected to the base of the IGBT chip 30A by an aluminum wire 78A1. A terminal block 72 is mounted on the insulating plate 10 on the right side of the output bus bar 22. The gate resistor 76A is fixed on the terminal block 72 by soldering. The gate resistor 76A is connected to the base of the IGBT chip 32A by an aluminum wire 78A2. A copper pattern 90 is provided on the back of the insulating plate 10.
Is formed, and heat is dissipated from the IGBT chip through the insulating plate 10.

The positive bus bar 20 and the output bus bar 22 are
A portion thinned to about 0.4 mm is joined to the insulating plate 10 by brazing.

The surfaces of the IGBT chips 30A and 32A are
Covered with a coating agent for chip protection,
In the space formed by the frame-shaped case 12 fixed on the insulating plate 10, a gel 100 is provided for chip protection.
Is filled.

According to the present embodiment, the positive electrode bus bar 20
Since the output busbar 22 and the output busbar 22 are arranged in parallel with each other, the inductance can be reduced.

The IGBT chip has a positive electrode bus bar 20.
Further, since it is directly attached to the output bus bar 22, the wiring distance can be further shortened.

Further, the negative electrode bus bar 24 is replaced by the positive electrode bus bar 2
0 is arranged in parallel with each other and the direction of the current flowing through the positive electrode bus bar 20 and the direction of the current flowing through the negative electrode bus bar 24 are opposite to each other, so that the inductance can be reduced.

Further, the negative electrode bus bar 24 is connected to the positive electrode bus bar 2
Since they are arranged parallel to each other on 0, it is not necessary to use a jumper plate as in the conventional case, and thus the inductance can be reduced.

In addition, the negative electrode bus bar 24 is connected to the positive electrode bus bar 2
0 arranged in parallel and further connecting the negative electrode bus bar 24 and the emitter chip of the IGBT chip fixed on the output bus bar 22 and the emitter and output of the IGBT chip fixed on the positive electrode bus bar 20. The inductance can be further reduced by making the aluminum wires connecting the busbars 22 parallel to each other and making the directions of the currents flowing through them opposite to each other.

Next, a circuit diagram of the semiconductor device according to the embodiment of the present invention will be described with reference to FIG.

Here, in the plan view shown in FIG. 1, four IGBT chips and four diodes are arranged. In this case, the first series circuit is arranged in parallel, and further,
This is because the second series circuit is also arranged in parallel. Here, the first series circuit is composed of one IGBT chip and a diode.
Only the second series circuit including the series circuit of 1 and the IGBT chip and the diode will be described.

In FIG. 3, thick solid lines represent bus bars, and broken lines represent aluminum wires.

IGBT chip 30A and diode 40A
The first circuit is configured by a series circuit including. In addition, the second circuit is configured by a series circuit including the IGBT chip 32B and the diode 42B.

The positive electrode bus bar 20 is an IGBT chip 30.
It is connected to the collector of A and the anode of the diode 42B. The negative electrode bus bar 24 is connected to the cathode side of the diode 40A via an aluminum wire 50B3, and I
Aluminum wire 50B on the emitter side of GBT chip 32B
2 are connected.

It is. Further, the output bus bar 22 is IG
A point through the aluminum wire 50A1 to the BT chip 30A, a connection point of the anode of the diode 40A, and the IGB
It is connected to a connection point between the collector of the T chip 32B and a point on the cathode side of the diode 42B via an aluminum wire 50A4.

When a signal is applied to the base of the IGBT chip 30A, a positive half wave is taken out via the output bus bar 22, and when a signal is applied to the base of the IGBT chip 32B, a negative half wave is output. It is taken out via 22 and an AC signal is obtained.

Diode 40A and diode 42B
Is a diode for commutation.

Here, according to the present embodiment, the positive electrode bus bar and the negative electrode bus bar are arranged in parallel with each other, and the currents flowing through them are in opposite directions.
Inductance can be reduced.

The output bus bar and the positive bus bar are also arranged in parallel with each other, so that the inductance can be reduced.

Further, the aluminum wire is parallel to the aluminum wire which is the opposite arm, and the flowing currents are in the opposite directions, so that the inductance can be reduced.

Further, the aluminum wire is parallel to the aluminum wire which is the opposite arm, and the flowing currents are in opposite directions, so that the inductance can be reduced.

Further, the distance between the reciprocating line from the current flowing from the positive electrode through the chip and returning to the output terminal can be made as small as the wire height and the insulator height, so that the inductance can be reduced by the magnetic field canceling action. . Therefore, the self-inductance and the mutual inductance in each part are greatly reduced, which can reduce the surge voltage and the switching loss. Since multiple chips have large inductance at distant positions and current imbalance is likely to occur, internal bending is eliminated as much as possible,
Inductance is reduced by paralleling closely.

The coefficient of linear expansion of the chip is about ⅙ times that of copper, and the coefficient of linear expansion of aluminum nitride is about ⅕ times that of copper. Since the chip, copper and aluminum nitride are connected in this order, Although expected to be affected by thermal stress, it is possible to prevent the solder life from being affected by the thermal stress action by optimizing the thickness of the IGBT chip mount portion of the bus bar.

Hereinafter, another embodiment of the present invention will be described.
This will be described with reference to FIGS. FIG. 4 is a plan view of a semiconductor device according to another embodiment of the present invention, and FIG.
FIG. 5 is a sectional view taken along line YY of FIG. 4.

In this embodiment, the IGBT chip and the diode arranged in series with the IGBT chip are arranged close to each other. Further, the busbars are arranged vertically symmetrically, that is, the first series circuit and the second series circuit forming the paired arms are arranged symmetrically, whereas the busbars are arranged symmetrically. In addition, although an arrangement including two IGBT chips and two diodes is shown here, the same arrangement as in FIG.
It may be arranged such that each IGBT chip and four diodes are arranged.

In FIG. 4, a positive electrode bus bar 120B used as a rectangular positive electrode terminal is joined on the rectangular insulating plate 110 on the left side of the drawing. A brazing material such as silver brazing is used for joining. The insulating plate 110 is made of, for example, an aluminum nitride plate.
The insulating plate 11 is on the right side of the positive electrode bus bar 120.
Above 0 is an output busbar 1 used as an output terminal.
22A is joined by brazing. The positive bus bar 120B and the output bus bar 122A are the same insulating plate 1
Mounted on 10, they are parallel to each other.
Further, the long axis direction of the rectangular positive electrode bus bar 120B and the long axis direction of the output bus bar 122A are parallel to each other, and in this respect as well, the positive electrode bus bar 120B and the output bus bar 1 are arranged.
22A are parallel to each other.

On the positive electrode bus bar 120B, an IGBT chip 130A for switching which is a power module and a diode 142 for commutation are formed by solder (not shown).
B is fixed. Therefore, in terms of electrical circuit, IGB
The collector of the T-chip 130A and the anode of the diode 142B are connected to the positive busbar 120B.

On the output bus bar 122A, a switching IGBT chip 132B which is a power module and a commutation diode 140A are fixed by solder (not shown). Therefore, in terms of electric circuit,
IGBT chip 132B collector and diode 140
The anode of A is connected to the output bus bar 22A.

The emitter of the IGBT chip 130A is connected to the output busbar 22 by the aluminum wire 150A1, and the cathode of the diode 142B is connected to the output busbar 122A by the aluminum wire 150A3. Here, aluminum wires 150A1 and 150A
Although each 3 is represented by two lines, a plurality of lines 3 are actually used in parallel. Aluminum wire 150
Since A1 and 150A3 are provided by wire bonding, there is a limit to the diameter of one wire.
Depending on the magnitude of the current flowing from the T-chip or diode, a plurality of them are used.

Positive bus bar 120B and output bus bar 12
On top of 2A, three cylindrical insulators 160A, 160
B and 160C are fixed. And this insulator 1
On top of 60A, 160B and 160C, the negative bus bar 1
24 is fixed. Therefore, the negative bus bar 124
Is parallel to the positive electrode bus bar 120B,
The directions of the currents flowing through the negative busbar 124 and the positive busbar 120B are opposite to each other.

To the negative bus bar 124, the emitter of the IGBT chip 132B is connected by the aluminum wire 150B1, and the cathode of the diode 140A is connected by the aluminum wire 150B3. Here, each of the aluminum wires 150B1 and 150B3 is represented by two lines, but in reality, a plurality of aluminum wires are used in parallel. Aluminum wires 150B1 and 150B3 are
Since the wire is provided by wire bonding, there is a limit to the diameter of one wire, and a plurality of wires are used depending on the magnitude of the current flowing from the IGBT chip or the diode.

Here, the aluminum wires 150A1 and 150
A3 and the aluminum wires 150B1 and 150B3 are kept parallel to each other. That is, although this point will be described in detail with reference to FIG. 5, the aluminum wire 150A1 and the aluminum wire 150B1 are parallel to each other, and the flowing current directions are opposite to each other. The aluminum wires 50B3 are parallel to each other and the flowing currents are in opposite directions.

Therefore, the emitter of the IGBT chip 130A is connected to the anode of the diode 140A, and the first
Constitutes a series circuit of. In addition, the IGBT chip 13
The 2B emitter is connected to the anode of the diode 142B to form a second series circuit. The IGBT chip 130A and the diode 140A that form the first circuit
Are arranged close to each other, so that magnetic field canceling can be performed by an alternating current component when the current is transferred from the IGBT chip to the diode during the commutation operation of the inverter. Further, the IGBT chip 132B and the diode 142B forming the 21st circuit are also arranged close to each other for the same reason.

The first series circuit and the second series circuit are connected in parallel to the positive bus bar 120B and the negative bus bar 124, respectively, and I of the first series circuit is connected.
The connection point between the emitter of the GBT chip and the anode of the diode, and the cathode of the diode of the second series circuit and the IG
The connection point of the collector of the BT chip is the output bus bar 122.
Commonly connected to A.

Further, a terminal block 170 is mounted on the insulating plate 110 on the left side of the positive electrode bus bar 120B. The gate resistor 174A is fixed on the terminal block 170 by soldering. Gate resistance 174
A is an IGBT chip 1 with an aluminum wire 178A1.
It is connected to the base of 30A. A terminal block 172 is mounted on the insulating plate 110 on the right side of the output bus bar 122A. A gate resistor 176B is fixed on the terminal block 172 by soldering. The gate resistor 176B is connected to the base of the IGBT chip 32B by an aluminum wire 178B2.

Further, the positive electrode bus bar 120B is connected to the positive electrode bus bar 120A, and the positive electrode bus bar 120B is connected to the positive electrode bus bar 120B.
The terminal portions on the left side of A and the negative bus bar 24 are parallel to each other. An output busbar 122B is connected to the output busbar 122A. The configurations of the positive electrode bus bar 120A and the output bus bar 122B will be described later with reference to FIG.

Heat is dissipated from the IGBT chip by the insulating plate 11.
Through 0.

Next, with reference to FIG. 5, a cross-sectional structure of the semiconductor device according to another embodiment of the present invention shown in FIG. 4 will be described.

A positive electrode bus bar 120B used as a positive electrode terminal is joined on the insulating plate 110 on the left side of the drawing. A brazing material such as silver brazing is used for joining. An L-shaped positive electrode bus bar 120A used as an input terminal is soldered to the positive electrode bus bar 120B. On the right side of the positive bus bar 120B and on the insulating plate 110, an output bus bar 122A used as an output terminal is joined by brazing. An L-shaped output bus bar 122B used as an output terminal is soldered to the output bus bar 122A. Positive bus bar 120B and output bus bar 122A
Are mounted on the same insulating plate 110,
Parallel to each other. Further, the long axis direction of the positive electrode bus bar 120B (direction orthogonal to the drawing) and the long axis direction of the output bus bar 122A (direction orthogonal to the drawing) are parallel to each other,
Also in this respect, the positive bus bar 120B and the output bus bar 122A are parallel to each other.

Solder 18 is placed on the positive electrode bus bar 120B.
0, a switching IGBT chip, which is a power module (not shown), and a commutation diode 142B.
Has been fixed. Therefore, in terms of electric circuit, the IGBT
The collector of the chip and the anode of the diode 142B
It is connected to the positive electrode bus bar 120B.

On the output bus bar 122A, a switching IGBT chip 132B which is a power module and a commutation diode (not shown) are fixed by solder 182. Therefore, in terms of electric circuit, I
The collector of the GBT chip 132B and the anode of the diode are connected to the output bus bar 122A.

The output bus bar 122A has a diode 1
The cathode of 42B is connected by an aluminum wire 150A3. Here, a plurality of aluminum wires 150A3 are used in parallel. Aluminum wire 150A3
Since the wire is provided by wire bonding, the diameter of one wire is limited, and a plurality of wires are used according to the magnitude of the current flowing from the IGBT chip or the diode.

Positive bus bar 120B and output bus bar 1
A cylindrical insulator 160B is fixed on 22A. Then, on the insulator 60B, the negative electrode bus bar 1
24 is fixed. Therefore, the negative bus bar 124
Are parallel to the positive busbar 120B and the positive busbar 120A, and the directions of the currents flowing through the negative busbar 124 and the positive busbars 120A and 120B are opposite to each other. In addition, the positive electrode bus bar 120A
An insulating spacer 19 is provided between the negative electrode bus bar 24 and the negative electrode bus bar 24.
2 is fixed.

The emitter of the GBT chip 132B is connected to the right side of the negative bus bar 124 by an aluminum wire 150A3. Further, the cathode of the diode (not shown) is connected to the negative electrode bus bar 12 by an aluminum wire.
4 are connected to the connection terminals. Here, a plurality of aluminum wires 150A3 are used in parallel. Since the aluminum wire 150A3 is provided by wire bonding, there is a limit to the diameter of one wire.
Depending on the magnitude of the current flowing from the chip or diode, a plurality are used.

The negative electrode bus bar 124 is made of the insulating material 60.
Via the positive electrode bus bar 120B and the output bus bar 12
Since it is supported on a plane different from that of 2A, there is a step between the negative electrode bus bar 124 and the emitter of the IGBT chip 132B. In the conventional wire bonding technology, when such a step is present, aluminum is used. Bonding with wires has been impossible, but since such a bonding technology has been developed in recent years that can be applied to such a stepped portion, such an arrangement is possible. Further, since the columnar insulator 160B is used between the positive electrode bus bar 120B and the negative electrode bus bar 124, the resonance phenomenon during ultrasonic bonding can be prevented.

Here, the aluminum wire 150A3 and the aluminum wire 150B1 are kept parallel to each other.
That is, aluminum wire 150A3 and aluminum wire 150B
1 are parallel to each other and the flowing currents are in opposite directions.

Therefore, the emitter of the IGBT chip 132B is connected to the anode of a diode (not shown) fixed on the positive electrode bus bar 120B to form a first series circuit. The emitter of the IGBT chip (not shown) fixed on the positive bus bar 120B is connected to the anode of a diode (not shown) fixed on the output bus bar 122A to form a second series circuit. The first series circuit and the second series circuit are connected in parallel to the positive bus bar 120B and the negative bus bar 124, respectively, and the IG of the first series circuit is connected.
The connection point between the emitter of the BT chip and the anode of the diode, and the cathode of the diode of the second series circuit and the IGB
The connection point of the collector of the T chip is the output bus bar 122A.
Connected in common. Further, since the first circuit and the second circuit are symmetrically arranged, the positive electrode bus bar 120A,
Since 120B and the negative bus bar 124 can be made symmetrical, and the currents evenly flow in the first and second circuits, the current distribution becomes uniform and the current imbalance can be reduced.

Further, a terminal block 170 is attached on the left side of the positive electrode bus bar 120 and on the insulating plate 110. The gate resistor 174A is fixed on the terminal block 170 by soldering. Gate resistance 174A
Is an IGBT chip 13 with an aluminum wire 178A1.
It is connected to the base of 0A. Also, output bus bar 1
A terminal block 172 is mounted on the insulating plate 110 on the right side of 22A. A gate resistor 176B is fixed on the terminal block 172 by soldering. The gate resistor 176B is connected to the base of the IGBT chip 132B by an aluminum wire 178B2. A copper pattern 190 is formed on the back side of the insulating plate 110, so that heat radiation from the IGBT chip is prevented from occurring in the insulating plate 110.
Done through.

Positive bus bar 120B and output bus bar 12
In 2A, the thinned portion of about 0.4 mm is joined to the insulating plate 110 by brazing.

The surface of the IGBT chip is covered with a coating agent for chip protection, and a gel 100 is filled on the surface of the IGBT chip for chip protection.

According to this embodiment, the first circuit and the second circuit
Since the circuits are arranged symmetrically, the currents from the positive busbars and the negative busbars flow evenly, so that the current distribution becomes uniform.

Since the IGBT chip and the diode forming the first circuit are arranged close to each other, the magnetic field canceling by the alternating current component becomes possible.

Further, since the positive electrode bus bar and the output bus bar are arranged in parallel with each other, the inductance can be reduced.

Since the IGBT chip is directly mounted on the positive electrode bus bar and the output bus bar, the wiring distance can be further shortened.

Further, since the negative electrode bus bar is arranged in parallel on the positive electrode bus bar and the direction of the current flowing through the positive electrode bus bar is opposite to the direction of the current flowing through the negative electrode bus bar, the inductance can be reduced.

Further, since the negative electrode bus bar is arranged in parallel on the positive electrode bus bar, it is not necessary to use a jumper plate as in the prior art, so that the inductance can be reduced.

Further, the negative electrode bus bar was arranged in parallel on the positive electrode bus bar, and further, it was fixed on the positive electrode bus bar and the aluminum wire connecting the negative electrode bus bar and the emitter of the IGBT chip fixed on the output bus bar. IGBT
The inductance can be further reduced by making the emitter of the chip and the aluminum wire connecting the output busbar parallel to each other, and by making the directions of the currents flowing through them opposite to each other.

Further, the distance between the reciprocating line from the current flowing from the positive electrode through the chip and returning to the output terminal can be made as small as the wire height and the insulator height, so that the inductance can be reduced by the magnetic field canceling action. . Therefore, the self-inductance and the mutual inductance in each part are greatly reduced, which can reduce the surge voltage and the switching loss. Since multiple chips have large inductance at distant positions and current imbalance is likely to occur, internal bending is eliminated as much as possible,
Inductance is reduced by paralleling closely.

The coefficient of linear expansion of the chip is about 1/6 times that of copper, and the coefficient of linear expansion of aluminum nitride is about 1/5 times that of copper. Since the chip, copper and aluminum nitride are connected in this order, Although expected to be affected by thermal stress, it is possible to prevent the solder life from being affected by the thermal stress action by optimizing the thickness of the IGBT chip mount portion of the bus bar.

[0096]

According to the present invention, it is possible to reduce the internal inductance in a semiconductor device of the two-circuit built-in type.

[0097]

[Brief description of the drawings]

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

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a circuit diagram of a semiconductor device according to an embodiment of the present invention.

FIG. 4 is a plan view of a semiconductor device according to another embodiment of the present invention.

FIG. 5 is a sectional view taken along line YY of FIG. 4;

[Explanation of symbols]

10, 110 ... Insulating plate 12 ... Case 20, 120A, 120B ... Positive busbar 22, 124A, 124B ... Output busbar 24, 124 ... Negative busbar 30A, 30B, 32A, 32B ... IGBT chip 40A, 40B, 42A, 42B ... Diode chips 50A1, 50A2, 50A3, 50A4, 50B1,
50B2, 50B3, 50B4, 78A1, 78A2
78B1, 78B2 ... Aluminum wire 60A, 60B, 60C, 60D, 60E, 60F ... Insulator 70, 72 ... Terminal block 74A, 74B, 76A, 76B ... Chip resistance 80, 82, 180, 182 ... Solder 90 ... Copper plate 100 ... Gel 192 ... Spacer

Claims (5)

[Claims] 1. A semiconductor in which a first circuit including a series circuit of a first IGBT chip and a first diode and a second circuit including a series circuit of a second IGBT chip and a second diode are arranged in parallel. In the device, a positive electrode bus bar fixed on an insulating substrate, an output bus bar arranged in parallel with the positive electrode bus bar, fixed on the insulating substrate, and fixed on the positive electrode bus bar, and its collector is connected. The above-mentioned first IGBT chip, which is fixed on the positive busbar, and the second diode whose anode is connected, and the second diode which is fixed on the output busbar and whose collector is connected. And the second IGBT chip, and the first diode fixed on the output busbar and having its anode connected A first connection conductor connecting the emitter of the first IGBT chip and the output busbar, a second connection conductor connecting the cathode of the second diode and the output busbar, and the first IGBT chip And above the second diode, a negative electrode bus bar fixed in parallel with the positive electrode bus bar via an insulator, and a third connecting conductor connecting the collector of the second IGBT chip and the negative electrode bus bar. A semiconductor device comprising: a cathode of the first diode and a fourth connection conductor that connects the negative busbar. 2. The semiconductor device according to claim 1, wherein the third and fourth connection conductors are arranged in parallel and close to the first and second connection conductors. 3. The semiconductor device according to claim 1, wherein the first IGBT fixed on the positive electrode bus bar.
The first diode fixed on the output bus bar is arranged in proximity to the chip, and the second diode fixed on the positive bus bar is fixed on the output bus bar. A semiconductor device in which the above-mentioned second IGBT chip is arranged in proximity. 4. The semiconductor device according to claim 3, wherein the first series circuit and the second series circuit are arranged symmetrically with respect to the positive electrode bus bar, the negative electrode bus bar, and the output bus bar. A semiconductor device characterized by being arranged. 5. The semiconductor device according to claim 1, further comprising a case fixed to the insulating plate, wherein a part of the negative electrode bus bar is held by the case.