JP2000150776A - Semiconductor module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a semiconductor module to be operated continuously without spreading breakdown to other semiconductor chips even when a failure occurs in one semiconductor chip, when a plurality of semiconductor chips is used in a state where the chips are connected in parallel with each other. SOLUTION: A high-power semiconductor module, in which a plurality of power semiconductor chips is arranged side by side and used in a state where the chips are connected in parallel with each other, is provided with a plurality of mounting substrates 12 which are respectively mounted with the semiconductor chips and arranged side by side. The module is also provided with emitter leads 43 which respectively connect the emitters of the chips to the emitter terminal E of the module, gate leads which respectively connect the gates of the chips to the gate terminal G of the module, and collector leads 45 which respectively connect the collectors of the chips to the collector terminal C of the module and are more easily fused by overcurrents than the emitter leads 43.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to a semiconductor module (semiconductor stack) using a plurality of semiconductor chips connected in parallel. It is applied to an insulated gate type bipolar transistor) module.

[0002]

2. Description of the Related Art FIG. 8 schematically shows an example of the appearance of an IGBT module.

In FIG. 8, an IGBT module main body is housed in a case 80, and an emitter terminal E,
The gate terminal G and the collector terminal C are led out of the case 80.

FIG. 9 schematically shows a cross-sectional structure of an example of a recent IGBT module. IGBT Module In FIG. 9, an IGBT module main body 91 and a gate circuit 92 for controlling the IGBT module main body are provided inside a case 90.
Is stored. The gate circuit section 92 has a control element mounted on a printed circuit board, and is disposed on the upper side of the IGBT module main body 91.

FIG. 10A is a top view schematically showing the inside of a conventional generally used IGBT module, and its cross-sectional structure along the line BB is schematically shown in FIG.
FIG. 10B shows an equivalent circuit of the IGBT module shown in FIG.
It is shown in (c).

In FIGS. 10 (a) and 10 (b), a mounting substrate 12 in which a conductive pattern 122 such as Cu is formed on both sides of a high heat conductive insulating substrate such as ceramics 121 on a metal base 11 made of Cu or the like. It is installed. In this case, the mounting substrate 12 is divided into two parts, for example, since the mounting substrate 12 is easily broken when the size is large.

[0007] Then, the conductor pattern 12 of the mounting board 12 is formed.
On 2 are mounted, for example, the collector surfaces of four IGBT chips 13 and the cathode surfaces of four FRD (fast recovery diode) chips 14. Usually, the IGBT chip 13 and the FRD chip 14 are used in pairs.

An emitter terminal E, a gate terminal G, and a collector terminal C are fixed on the metal base 11 via an insulator (not shown).
Between the emitter of the T chip 13, the gate terminal G and the IGB
Between the gate of the T chip 13, between the collector terminal C and the chip mounting surface conductive pattern 122 of the mounting substrate 12, and between the emitter of the IGBT chip 13 and the FRD chip 14.
Between each of the bonding wires 15
Connected by

Thus, the four IGBT chips 1
3 each IGBT element and each FR of four FRD chips 14
The D elements are connected in parallel.

By connecting a plurality of IGBT modules as described above and connecting them in parallel, a high power IGB
A T module is configured. The inverter device is configured by using a plurality of high power IGBT modules.

A typical inverter device includes a four-chip IGBT module 10 as shown in FIGS. 10A and 10B, for example, as shown in the circuit of FIG.
One large power IGBT module group is used in parallel (i.e., a total of 60 IGBT modules 10 are used) to constitute one IGBT module group.

Further, in the neutral point clamp type three-level inverter device, ten IGBT modules 10 as shown in FIGS. 10 (a) and 10 (b) are arranged in parallel, for example, as shown in the circuit of FIG. 1 high power IGBT module group
By using two units (that is, using a total of 120 IGBT modules 10), one unit is configured.

In a large-sized plant using 10 to 30 inverters as described above,
Since a workpiece flows in a flow operation in each manufacturing process, if even one inverter device is stopped, all the processes are stopped, and it takes a long time to recover, so that a great loss is caused.

In particular, in a large-sized plant device using 30 three-level inverter devices as shown in FIG. 12, an IGBT as shown in FIGS.
The number of modules 10 used is 3600 (= 120 × 30), and the total number of IGBT chips and FRD chips used is 28800
(= 3600 × 4 × 2).

In a large-scale plant apparatus using a large number of chips as described above, the defect rate of one chip is 10%.
If it is about 0 fit (failure in time), a failure occurs about once every four months, and if the whole system stops due to the occurrence of the failure, a large operation loss occurs.

By the way, in the conventional IGBT module, when one chip has a defect and is destroyed,
If an overcurrent occurs in the bonding wire 15 connected to the wire 15 and the wire 15 is broken, an arc (spark) generated when the wire 15 is broken causes the damage to spread to an adjacent chip.

In the conventional high power IGBT module, when one chip of a certain IGBT module is broken, the collector potential of this chip is applied to the gate inside the chip, and the gate circuit (see FIG. (Not shown), the gate of another IGBT module is added, and the other IGBT module also leads to overcurrent breakdown.

Therefore, in a conventional inverter device using a large number of high power IGBT modules and a large plant device using the same, if one of the chips of a certain IGBT module is damaged, the destruction spreads to another IGBT module, and the inverter device is damaged. Operation and the operation of the entire plant system are stopped.

[0019]

As described above, a conventional semiconductor module in which a plurality of semiconductor chips are juxtaposed and connected in parallel is connected when a chip is damaged due to a defect. There is a problem that an arc generated when an overcurrent occurs in the bonding wire and the wire breaks due to an overcurrent causes damage to be spread to an adjacent chip.

Also, in a conventional high-power semiconductor module in which a plurality of the above-described semiconductor modules are connected in parallel, an inverter using the same, and a large-sized plant using the same,
If one of the chips of a certain semiconductor module is damaged, the destruction spreads to another semiconductor module, and furthermore, there is a problem that the operation of the inverter device and the operation of the entire plant system are stopped.

The present invention has been made in order to solve the above-mentioned problem. Even when one of a plurality of semiconductor chips arranged in parallel and connected to each other fails, the other semiconductor chips are not destroyed. It is an object of the present invention to provide a semiconductor module which can be prevented from spreading and can be operated continuously.

[0022]

According to a first aspect of the present invention, there is provided a semiconductor module, comprising: a mounting substrate; a semiconductor chip mounted on the mounting substrate and connected in parallel; and an emitter of each semiconductor chip connected to an emitter terminal of the module. An emitter lead provided for connecting a gate of each semiconductor chip to a gate terminal of a module; and a gate lead provided for connecting a collector of each semiconductor chip to a collector terminal of the module. And a collector lead which is more easily melted than the emitter lead by an overcurrent.

According to a second aspect of the present invention, in the semiconductor module of the first aspect, a partition member having an arc shielding function is further provided between the plurality of mounting substrates.

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings.

<First Embodiment> FIG. 1A is a top view schematically showing the inside of an IGBT module according to a first embodiment, and schematically shows a cross-sectional structure along the line BB. 1
1 (b), the partition member in FIG. 1 (b) is taken out, and an example thereof is schematically shown in FIG. 1 (c).

The equivalent circuit of this IGBT module is the same as that shown in FIG.

In FIGS. 1A and 1B, an insulating substrate (for example, ceramics 121) having high thermal conductivity is placed on a metal base 11 made of Cu or the like via an insulator having good thermal conductivity. Conductor pattern 122 such as Cu on both surfaces
Is mounted.

In this case, since the mounting board 12 is liable to be broken when the size is large, the mounting board 12 is divided into, for example, four units in units of as small a size as possible. The collector surface of the IGBT chip 13 and the cathode surface of one FRD chip 14 are mounted.

The mounting substrate 12 may not be divided, and a plurality of IGBTs may be mounted on one substrate 12.

On the metal base 11, an emitter terminal E, a gate terminal G, and a collector terminal C are fixed via an insulator (not shown) having good thermal conductivity.

Then, the IGBT chip 13 and the FRD chip 14 on each of the mounting substrates 12 on the metal base 11
Is covered with an insulating case 15.

Further, a partition member 16 is provided between each of the mounting boards 12 to prevent an arc from turning to a chip on an adjacent mounting board 12 even if one of the chips is broken. ing.

This partition member 16 is, for example, shown in FIG.
As shown in FIG. 3, the lower end face of the frame 160 and the lower end face of the partition plate 16 are fixed on the metal base 11 by, for example, an adhesive. You. The insulating frame 160 and the partition plate 16 are made of, for example, hexafluoride resin, PPS, PBT, or the like.

The metal base 11 is covered with the IG.
A portion that is higher than the BT chip 13 and the FRD chip 14 and lower than the height of the partition plate 16 and the frame 160 is covered with a gel-like insulating material (for example, Si gel) 17.

Then, the emitter terminal E and the emitter of the IGBT chip 13 are connected by a bonding wire 43, and the gate terminal G and the gate of the IGBT chip 13 are connected by a bonding wire 44.
The collector terminal C and the chip-mounting surface conductive pattern 122 of the mounting substrate 12 are connected by bonding wires 45, and the emitter of the IGBT chip 13 is connected to the FRD.
A bonding wire 41 is provided between the chip 14 and the cathode.
Connected by

In this case, as the bonding wire 41 between the emitter of the IGBT chip 13 and the cathode of the FRD chip 14, four Al wires having a diameter of about 500 μm are used.

The bonding wire 43 between the emitter terminal E and the emitter of the IGBT chip 13 is
Four Al (aluminum) wires of about 500 μmφ are used.

The bonding wire 44 between the gate terminal G and the gate of the IGBT chip 13 is
One thin Al wire of about 0 μmφ is used.

The collector terminal C and the mounting substrate 12
As the bonding wire 45 between the chip mounting surface conductive pattern 122 and the chip mounting surface conductive pattern 122, two Al wires of about 500 μmφ are used.

Such bonding wires 41 to 45
Of each of the four IGBT chips 13
The BT element and each FRD element of the four FRD chips 14 are connected in parallel.

A high-power IGBT module is configured by using a plurality of IGBT modules as described above and connected in parallel, and an inverter device is configured by using a plurality of the high-power IGBT modules.

It is to be noted that a normal inverter device has a large power I in which ten IGBT modules as shown in FIGS. 1A and 1B are arranged in parallel as in the circuit shown in FIG. 11, for example.
Uses 6 GBT modules (that is, IGBT modules)
One module is constituted by using a total of 60 modules).

Further, the three-level inverter device of the neutral point clamp system is, for example, as shown in the circuit of FIG.
A high-power IGBT module group in which ten IGBT modules as shown in FIGS.
(I.e., a total of 120 IGBT modules
One unit is configured.

In a large plant,
One system is constituted by using, for example, 10 to 30 inverter devices as described above.

500 μm included in the collector lead path
The wire 45 composed of two Al wires of about φ and the wire 44 composed of one thin Al wire of about 200 μm φ included in the gate lead path are different from the wire 43 composed of four Al wires of about 500 μm φ included in the emitter lead path. Are also easily cut.

Therefore, according to the IGBT module of the first embodiment and the semiconductor device using the same, when one IGBT or FRD chip is broken by an overcurrent, the wire 45 on the collector side is connected to the emitter side. And the connection of the destructive chip is cut off.

Further, even if the collector is short-circuited with the collector inside the chip due to the destruction of the chip, the gate becomes high potential and current flows to an external gate circuit (not shown).
Since the bonding wire 44 of the gate is melted, no other module is broken through the gate circuit.

Therefore, even if one chip is destroyed for some reason, the destruction does not spread to other element blocks and other modules, the operation of the entire system is not stopped, and continuous operation is possible.

In the first embodiment, the collector side,
Although an Al wire was used as the bonding wire on the gate side, a wire having a fuse function may be used as the wire material on the collector side and the gate side (the emitter side does not have a fuse function as a wire material). It does not matter).

In this case, the operation of disconnecting the circuit of the destroyed element block from the system is further accelerated. When a wire having a fuse function is used, the number and thickness of the collector-side and gate-side bonding wires are changed to the number and thickness of the emitter-side bonding wires as in the first embodiment. You don't have to.

<First Modification of First Embodiment> FIG. 2 is a top view schematically showing a part (mainly a gate wiring portion) of an IGBT module according to a first modification of the first embodiment. The cross-sectional structure along the -B line is the same as that shown in FIG. 1B, and its equivalent circuit is the same as that shown in FIG.

The IGBT module shown in FIG.
As compared with the IGBT module of the first embodiment shown in FIG. 1A, a gate relay connection terminal GT corresponding to each mounting substrate 12 is disposed on a metal base 11 via an insulator having good thermal conductivity. , This gate relay connection terminal GT and each IGB
Bonding wires 15 are connected to the gates of the T chips 13 respectively. A difference is that a fuse (or a gate series resistor with a fuse function) 21 is connected between each of the gate relay connection terminals GT and the gate terminal G, and the other components are the same.

When a plurality of IGBT modules are connected in parallel, the gate terminal G is connected to a plurality of I
It is connected to a gate bus bar 22 commonly used in the GBT module via, for example, a screwed Cu plate 23.

According to the IGBT module of FIG. 2, when an element on a certain chip is destroyed, the gate potential inside the chip rises, and when a current tries to flow into an external gate circuit, a fuse (or a fuse with a fuse function) is required. The current is blocked by shutting off the gate series resistor 21). In this case, if the resistor 21 with the fuse function is used, it functions not only as a cutoff of the circuit but also as a balance resistor inserted in series with the gate of each chip.

<Modification 2 of First Embodiment> FIG. 3 is a top view schematically showing a part (mainly a collector wiring portion) of an IGBT module according to a second modification of the first embodiment. The cross-sectional structure along the -B line is the same as that shown in FIG. 1B, and its equivalent circuit is the same as that shown in FIG.

The IGBT module shown in FIG.
As compared with the IGBT module of the first embodiment shown in FIG. 3A, a fuse (or a gate series resistor with a fuse function) is provided between the collector (conductive pattern on the mounting substrate 12) and the collector terminal C of each IGBT chip. ) 31 is, for example, connected by soldering, and the others are the same.

When a plurality of IGBT modules are connected in parallel, the collector terminal C is connected, for example, to a Cu plate 33 screwed to a collector bus bar 32 commonly used by the plurality of IGBT modules. Connected through.

Parts not shown (such as gate circuits) are the same as in the first embodiment or the first modification.

According to the IGBT module of FIG. 3, when an element of a certain chip is destroyed and an overcurrent flows through a corresponding fuse (or a gate series resistor with a fuse function) 31, the connection of the destroyed element block is cut off. It has a function to do.

<Second Embodiment> FIG. 4 shows a part (mainly a collector wiring portion) of an IGBT module according to a second embodiment.
FIG. 10B is a top view schematically showing a cross-section taken along a line BB. The cross-sectional structure is almost the same as that shown in FIG. 1B, and its equivalent circuit is the same as that shown in FIG. The same is true.

The IGBT module shown in FIG.
(1) Compared with the IGBT module of the first embodiment shown in (a), (1) a collector terminal C1 corresponding to each mounting substrate 12 on a metal base 11 via an insulator (not shown) having good thermal conductivity. To C4 are arranged and led out, and bonding wires 15 are connected between the collector terminals C1 to C4 and the collector of each IGBT chip 13, respectively. (2) Further, a plurality of IGB
T modules are connected in parallel, and a fuse 7 is immediately blown between a collector bus bar 71 commonly used by a plurality of IGBT modules and the collector terminals C1 to C4.
2 is connected for example by screwing,
Others are the same.

Parts not shown (gate circuits and the like) are the same as those in the first embodiment or its modifications.

According to the high power IGBT module in which a plurality of IGBT modules are connected in parallel as shown in FIG. 4, when an element of a certain chip is destroyed and an overcurrent flows through the corresponding immediate blow fuse 72, the connection of the destroyed element block is performed. Has the function of cutting off.

<Modification 1 of Second Embodiment> FIG. 5 is a top view schematically showing a part (mainly a gate wiring portion) of an IGBT module according to a first modification of the second embodiment. The cross-sectional structure along the -B line is the same as that shown in FIG. 1B, and its equivalent circuit is the same as that shown in FIG.

The IGBT module shown in FIG.
(1) Compared with the IGBT module of the first embodiment shown in (a), (1) a gate terminal corresponding to each mounting substrate 12 on a metal base 11 via an insulator (not shown) having good thermal conductivity. G1 to G4 are provided and led out to the outside. The gate terminals G1 to G4 and each IGBT chip 1
(2) Further, a plurality of IGBT modules are connected in parallel, and a gate bus bar 51 commonly used by a plurality of IGBT modules. The difference is that a fuse (or a resistor with a fuse function) 52 is connected between each of the gate terminals G1 to G4 by, for example, screwing, and the others are the same.

Parts not shown (collectors and the like) are the same as in the second embodiment.

According to the IGBT module of FIG. 5, when an element of a certain chip is destroyed, the gate potential inside the chip rises and the fuse 52 is cut off when current tries to flow into an external gate circuit. This blocks the current. In this case, if the resistor 52 having a fuse function is used, the resistor 52 functions not only as a circuit breaker but also as a balance resistor inserted in series with the gate of each chip.

<Modification 2 of Second Embodiment> FIG. 6 schematically shows a part (mainly a gate wiring portion) of an IGBT module according to a second modification of the second embodiment as viewed from the top, and shows an IGBT module. The connection relationship between the gate terminal and the gate circuit outside the IGBT module is shown.
The sectional structure of the T module along the line BB is the same as that shown in FIG. 1B, and its equivalent circuit is shown in FIG.
This is the same as that shown in FIG.

The IGBT module shown in FIG.
(1) Compared to the IGBT module of the first embodiment shown in (a), (1) a gate terminal G1 corresponding to each mounting substrate on a metal base 11 via an insulator (not shown) having good thermal conductivity. To G4 and are led out to the outside. The gate terminals G1 to G4 and each IGBT chip 13
(2) Furthermore, the output signal of the gate control circuit 61 is supplied to the individual power supply circuit 6 via the photocoupler 62.
A gate circuit 60 coupled (transferred) to the input side of an output stage circuit (gate driver) 64 having a gate circuit 3 is provided outside the IGBT module. (3) Each of the gate terminals G1 to G4 is The difference is that it is connected to the output node of the gate driver 64 in the circuit 60, and the others are the same.

Note that the gate circuit 60 is, for example, as shown in FIG.
As shown in (1), it is mounted and housed on a printed circuit board disposed above the IGBT module inside the same case.

Parts not shown (collectors and the like) are the same as in the second embodiment.

According to the IGBT module of FIG. 6, a gate terminal is derived for each element block, and each gate is controlled by a driver 64 that receives an output signal of a gate control circuit through a photocoupler 62.

Therefore, one gate of the IGBT module (and the gate terminal connected to it)
Does not spread to other element blocks or other modules.

The entire gate circuit shown in FIG.
An intelligent IGBT module incorporated in the GBT module may be configured.

FIG. 7 shows a modification of the partition member shown in FIG.

The partition member shown in FIG. 7 is integrated with an insulating case 70 which is put on the metal base 11 shown in FIG. 1B so as to surround the IGBT chip 13 and the FRD chip 14 on each mounting board 12. The lower end surface of the case 70 and the lower end surface of the partition plate 71 are fixed on the metal base 11.

In this case, the case 70 has an emitter terminal E, a gate terminal G and a collector terminal C (not shown) fixed on the metal base 11 via an insulator (not shown) having good heat conductivity. And one end of each of the emitter terminal E, the gate terminal G, and the collector terminal C is led out of the case 70.

[0078]

As described above, according to the semiconductor module of the present invention, even if a failure occurs in one of a plurality of semiconductor chips arranged in parallel and connected in parallel, the damage is spread to other semiconductor chips. So that continuous operation is possible.

Further, when the present invention is applied to a large plant using a large number of semiconductor modules, even if one of a plurality of semiconductor chips arranged in parallel and damaged is broken, only that part can be disconnected from the system. Since other element blocks, other modules, or control circuits are not destroyed, it is possible to prevent the operation of the plant from being lost without stopping the entire system.

[Brief description of the drawings]

FIG. 1 is a top view and a sectional view schematically showing the inside of an IGBT module according to a first embodiment of the present invention, and a perspective view schematically showing a partition member taken out.

FIG. 2 is an IGBT according to a first modification of the first embodiment of the present invention;
FIG. 3 is a top view schematically showing a part (mainly a gate wiring part) of a module.

FIG. 3 is an IGBT according to a modification 2 of the first embodiment of the present invention;
FIG. 4 is a top view schematically showing a part of a module (mainly, a collector wiring part).

FIG. 4 is a top view schematically showing a part (mainly a collector wiring portion) of an IGBT module according to a second embodiment of the present invention.

FIG. 5 is an IGBT according to a first modification of the second embodiment of the present invention.
FIG. 3 is a top view schematically showing a part (mainly a gate wiring part) of a module.

FIG. 6 is an IGBT according to a second modification of the second embodiment of the present invention.
FIG. 4 is a diagram schematically showing a part (mainly a gate wiring portion) of a module as viewed from above, and showing a connection relationship between a gate terminal of the IGBT module and a gate circuit outside the IGBT module.

FIG. 7 is a perspective view showing a modification of the partition member shown in FIG. 1 (c).

FIG. 8 is a perspective view schematically showing an example of the appearance of the IGBT module.

FIG. 9 is a sectional view schematically showing an example of a recent IGBT module.

FIG. 10 is a top view, a cross-sectional view, and an equivalent circuit diagram showing the inside of a conventional generally used IGBT module.

FIG. 11 is a configuration explanatory diagram showing an example of one normal inverter device using a large number of IGBT modules.

FIG. 12 is a structural explanatory view showing an example of one neutral-point-clamped three-level inverter device using a large number of IGBT modules.

[Explanation of symbols]

 11: Metal base, 12: Mounting board, 13: IGBT chip, 14: FRD chip, E: Emitter terminal, G: Gate terminal, C: Collector terminal, 15: Insulating case, 16: Partition member.

Claims (10)

[Claims] A mounting board; a semiconductor chip mounted on the mounting board and connected in parallel; an emitter lead provided to connect an emitter of each semiconductor chip to an emitter terminal of a module; A gate lead provided to connect the gate of the chip to the gate terminal of the module; and a gate lead provided to connect the collector of each semiconductor chip to the collector terminal of the module. A semiconductor module comprising: a collector lead. 2. The semiconductor module according to claim 1, wherein said gate lead is more easily melted than said emitter lead due to an overcurrent. 3. The semiconductor module according to claim 1, wherein the emitter lead, the gate lead, and the collector lead each include a bonding wire in series, and the number of bonding wires connected to the collector of each of the semiconductor chips. Is smaller than the number of bonding wires connected to the emitter of each semiconductor chip. 4. The semiconductor module according to claim 3, wherein a bonding wire connected to a gate of each semiconductor chip is thinner than a bonding wire connected to a collector of each semiconductor chip. module. 5. The semiconductor module according to claim 1, wherein said collector lead includes a fuse or a bonding wire made of a material having a fuse function in series. 6. The semiconductor module according to claim 2, wherein the gate lead includes, in series, a fuse, a bonding wire of a material having a fuse function, or a resistor having a fuse function. A semiconductor module characterized by the above-mentioned. 7. The semiconductor module according to claim 1, wherein a partition member having an arc shielding function is provided between said plurality of mounting boards. 8. A plurality of mounting boards arranged in parallel, a semiconductor chip mounted on each of the plurality of mounting boards and connected in parallel, and provided to correspond to each of the mounting boards and led out to the outside. A plurality of collector terminals connected to the collector of the semiconductor chip on the corresponding mounting substrate, and a plurality of fuses respectively connected between the respective collector terminals and an external collector bus bar. A semiconductor module characterized by the above-mentioned. 9. A plurality of mounting boards arranged in parallel, and a plurality of gate terminals provided corresponding to each of the mounting boards and led out to the outside and connected to gates of semiconductor chips on the corresponding mounting boards. And a plurality of fuses or resistors with a fuse function respectively connected between the respective gate terminals and an external gate bus bar. 10. A plurality of mounting boards arranged in parallel, and a plurality of gate terminals provided corresponding to each of the mounting boards and led out to the outside and connected to gates of semiconductor chips on the corresponding mounting boards. A plurality of outputs of a gate control circuit, each of which is coupled to an input side of a plurality of output stage gate drivers each having an individual power supply circuit via a photocoupler. A semiconductor module, wherein a gate drive signal is supplied independently from an output stage gate driver.