JP6873382B2 - Semiconductor device - Google Patents

Description

The present invention relates to a semiconductor device suitable for drive control of an in-vehicle motor.

Vehicles such as hybrid vehicles and electric vehicles are provided with a plurality of motors and inverters for controlling these motors.
Of these, the power module constituting the inverter is often configured to have a power semiconductor element such as an IGBT (insulated gate bipolar transistor), and the semiconductor element generates heat due to the switching operation. Therefore, a cooler is installed to remove this heat and prevent the semiconductor from overheating. A combination structure of a cooler and a power module is disclosed in, for example, Patent Document 1.

As shown in FIG. 2 of Patent Document 1, the cooler main body (100) (the numbers in parentheses indicate the reference numerals described in Patent Document 1; the same applies hereinafter) is the lower housing (140) and the lower portion thereof. It is composed of an upper housing (130) that closes the opening of the housing (140). Then, the first element mounting area (101) and the second element mounting area (102) are assigned to the upper housing (130), and between the first element mounting area (101) and the second element mounting area (102). A bus bar (133) is arranged in the intermediate region (103) of the above.

As shown in FIG. 1 of Patent Document 1, a structure in which a bus bar (113) traverses between a power module in the first element mounting region (101) and a power module in the second element mounting region (102) like a spine. Therefore, the bus bar (113) becomes long. When the bus bar (113) becomes long, the parasitic inductance becomes large, the surge voltage becomes large, and as a result, the loss increases, and the cooler main body (100) becomes large, so that the semiconductor device becomes large.

Further, although not disclosed in Patent Document 1, it is desired that this type of semiconductor device includes a smoothing capacitor that suppresses voltage fluctuations.
In FIG. 2 of Patent Document 1, there is a vacancy in the vicinity of the lower housing (140) of the cooler main body (100) (the surface opposite to the upper housing (130)).
Therefore, conventionally, the smoothing capacitor is arranged on the side opposite to the bus bar (133) of the cooler main body (100). Then, the bus bar extending from the smoothing capacitor to the power module bypasses the cooler main body (100), the bus bar becomes longer, and the surge voltage becomes larger.

In addition, if the portion connecting the bus bars to each other has a fastening structure consisting of bolts and nuts, this fastening structure occupies space, which leads to an increase in the size of the semiconductor device.

With the demand for miniaturization of semiconductor devices, semiconductor devices that can omit the fastening structure consisting of bolts and nuts and have a small surge voltage are desired.

Japanese Unexamined Patent Publication No. 2012-230960

An object of the present invention is to provide a semiconductor device capable of omitting a fastening structure composed of bolts and nuts and reducing the surge voltage.

The invention according to claim 1 is a semiconductor device including a power module, a cooler arranged below the power module to cool the power module, and a smoothing capacitor arranged below the cooler.
The cooler has a through hole in a portion located between adjacent power modules.
The smoothing capacitor has a bus bar that reaches the power module through the through hole.
The power module has a module-side terminal extending toward the bus bar, and a terminal relay member interposed between the module-side terminal and the bus bar.
The bus bar is arranged so as to face the module side terminal.
The terminal relay member, the module side terminal, and the bus bar are joined by ultrasonic vibration.

The invention according to claim 2 is characterized in that the power module is housed in a resin module case, and the terminal relay member is integrally molded so as to be exposed from the module case.

The invention according to claim 3 is characterized in that the power module is molded with a molding resin, and the terminal relay member is integrally molded so as to be exposed from the molding resin.

The invention according to claim 4 is characterized in that the cooler has a ladder shape.

In the invention according to claim 1, a through hole is provided in the cooler interposed between the power module and the smoothing capacitor, and the bus bar extending from the smoothing capacitor reaches the power module after passing through the through hole.
Busbars can be short enough because there is no need to bypass the cooler. In addition, the lengths of a plurality of bus bars ranging from a plurality of smoothing capacitors to a plurality of power modules can be made uniform.
That is, since each bus bar connecting the smoothing capacitor and the power module is evenly distributed and the wiring length can be shortened, the surge voltage can be suppressed.

In addition, in the invention according to claim 1 , a terminal relay member is interposed between the module side terminal and the bus bar.
The terminal relay member makes it easy to connect the module side terminal and the bus bar by ultrasonic waves or the like. Compared with the case of fastening with bolts and nuts, the number of parts can be reduced, the connection portion can be miniaturized, and the semiconductor device can be miniaturized.
Therefore, according to the present invention, there is provided a semiconductor device capable of omitting a fastening structure composed of bolts and nuts and reducing the surge voltage.

In the second aspect of the present invention, the power module is housed in a resin module case, and the terminal relay member is integrally molded so as to be exposed from the module case, so that the internal space of the power module is not sacrificed. , Terminal relay members can be installed.

In the invention according to claim 3 , since the power module is molded by the molding resin and the terminal relay member is integrally molded so as to be exposed from the molding resin, the terminals are not sacrificed in the internal space of the power module. A relay member can be installed.

In the invention according to claim 4 , since the cooler has a ladder shape, each bus bar connecting the condenser and the power module is evenly distributed, and the bus bar is formed through a through hole formed between the treads of the ladder. The wiring length can be shortened by passing it through.

It is a perspective view of the power module which concerns on this invention. It is an exploded perspective view, the main part enlarged view and the perspective view of the semiconductor device which concerns on this invention. It is a figure explaining the procedure of joining a module side terminal and a bus bar to a terminal relay member. It is a figure explaining the procedure of joining a module side terminal and a bus bar to a terminal relay member which concerns on a modification.

Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings shall be viewed in the direction of the reference numerals.

As shown in FIG. 1, the power module 20 constituting the semiconductor device 10 is provided in the cooler 30. The power module 20 includes an insulating substrate 21, a semiconductor element 28 and a diode 29 provided on the insulating substrate 21, a beam lead 22 as a module-side terminal connected to the insulating substrate 21, the semiconductor element 28 and the diode 29, and a motor. It includes an output bus bar 23 extending to the side and a plurality of signal pins 25 for connecting a gate drive board. The components of the power module 20 are surrounded by a module case 26, and the module case 26 is filled with a molding resin 27 (see FIG. 3).

As shown in FIG. 2A, the semiconductor device 10 according to the present invention cools a plurality of (six in this example) power modules 20 and the power modules 20 arranged below the power modules 20. It includes a cooler 30 and a smoothing condenser 40 arranged below the cooler 30.

The smoothing capacitor 40 is housed in a capacitor case 41 and has a PN (plus / minus) bus bar 42 extending upward to the outside of the capacitor case 41. The PN (plus / minus) bus bar 42 is hereinafter simply referred to as the bus bar 42.

The cooler 30 has a streak-like or elongated rectangular through-hole 31 that penetrates vertically at a portion located between the adjacent power modules 20 and 20. That is, the cooler 30 has a ladder shape. Since it has a ladder shape, it has a through hole 32 at a portion along the power module 20 at the end. In this example, the cooler 30 has five through holes 31 and one through hole 32.

As shown in FIG. 3, which is a sectional view taken along line 3-3 of FIG. 2C, the power module 20 includes an insulating substrate 21 provided on the cooler 30, a semiconductor element 28 provided on the insulating substrate 21, and the semiconductor element 28. It includes a beam lead 22 as a module-side terminal extending from the semiconductor element 28, and a plurality of gate drive board connection signal pins 25. Specifically, the insulating substrate 21 is composed of an insulating substrate 21a and a metal layer 21b integrally provided on both sides of the insulating substrate 21a. Members such as the insulating substrate 21 and the semiconductor element 28 are connected by solder.

In addition, the power module 20 has a module case 26 that encloses the components and a molding resin 27 (shown by an imaginary line) that fills the module case 26.
Further, in addition, the module case 26 is locally provided with a terminal relay member 50. The module case 26 is generally made of resin. On the other hand, the terminal relay member 50 is a metal piece. The metal piece has good electrical conductivity and high rigidity.

In FIG. 2A, the cooler 30 is mounted on the smoothing condenser 40. At this time, the bus bar 42 shown in FIG. 2B passes through the through hole 31 or 32 provided in the cooler 30. Then, in FIG. 2C, the bus bar 42 approaches the terminal relay member 50.
Traditional busbars are longer because they bypass the cooler. On the other hand, the bus bar 42 of the present invention is sufficiently short because it penetrates the cooler 30 as is clear from the figure. As is clear from FIG. 2A, the plurality of bus bars 42 have the same shape and length.

Next, as shown in FIG. 3, the vibrators 52 and 52 are placed on the beam lead 22 and the bus bar 42 with the terminal relay member 50 interposed between the beam lead 22 as the module side terminal and the bus bar 42. .. Next, these oscillators 52 and 52 are narrowed. Then, the beam lead 22 comes into contact with one surface of the terminal relay member 50, and the bus bar 42 comes into contact with the other surface. In this state, the vibrators 52 and 52 are ultrasonically vibrated. This vibration causes the contact area to generate heat and melt. When the vibration is stopped in this state, the beam lead 22 and the bus bar 42 are joined to the terminal relay member 50.
This joint structure is much smaller in space than when fastening with bolts and nuts. Moreover, since bolts and nuts are not required, the number of parts can be reduced.
The terminal relay member 50 may be interposed between the output bus bar 23 and the beam lead 22.

The advantages of the terminal relay member 50 will be further described.
In FIG. 3, when the terminal relay member 50 is omitted and the bus bar 42 is directly fused to the beam reed 22, the beam reed 22 and the bus bar 42 are both thin metal plates and have low rigidity, so that ultrasonic vibrations occur. At that time, there is a concern that the beam reed 22 will vibrate together. This vibration may adversely affect the elements and circuits mounted on the power module 20. In this respect, if the terminal relay member 50 having high rigidity is provided, the terminal relay member 50 prevents vibration, so that the vibration of the beam lead 22 and the bus bar 42 can be suppressed.

Next, a modified example according to the present invention will be described with reference to FIG.
As shown in FIG. 4, a flat plate-shaped terminal relay member 50 is placed on the module-side terminal (metal layer) 22 of the insulating substrate 21 and connected by solder (a part of the solder is a module-side terminal) or the like. Then, the entire power module is molded with the molding resin 27.
Next, the tip of the bus bar 42 is placed on the terminal relay member 50, and the vibrator 52 is applied to the bus bar 42 from above. The bus bar 42 is fused with the terminal relay member 50 by the vibrator 52.

In Figure 4, since the terminal relay member 50 across more power modules are supported directly by the module terminal (copper layer) 22 is molded, it is possible to omit the module case 26. Therefore, the terminal relay member 50 may be included in the power module 20, and the arrangement position is arbitrary as long as it is in the power module 20.

The present invention is suitable for semiconductor devices mounted on vehicles such as hybrid vehicles and electric vehicles.

10 ... Semiconductor device, 20 ... Power module, 22 ... Module side terminal (beam lead / copper layer), 26 ... Module case, 27 ... Molding resin, 30 ... Cooler, 31, 32 ... Through hole, 40 ... Smoothing capacitor, 42 ... Bus bar (PN bus bar), 50 ... Terminal relay member.

Claims (4)

In a semiconductor device including a power module, a cooler arranged below the power module to cool the power module, and a smoothing capacitor placed below the cooler.
The cooler has a through hole in a portion located between adjacent power modules.
The smoothing capacitor has a bus bar that reaches the power module through the through hole.
The power module has a module-side terminal extending toward the bus bar, and a terminal relay member interposed between the module-side terminal and the bus bar.
The bus bar is arranged so as to face the module side terminal.
A semiconductor device characterized in that the terminal relay member, the module side terminal, and the bus bar are joined by ultrasonic vibration. The power module is housed in a resin module case.
The semiconductor device according to claim 1, wherein the terminal relay member is integrally molded so as to be exposed from the module case. The power module is molded with a molding resin.
The semiconductor device according to claim 1, wherein the terminal relay member is integrally molded so as to be exposed from the molding resin. The semiconductor device according to any one of claims 1 to 3, wherein the cooler has a ladder shape.

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