JPH11307721A - Power module device and manufacture therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of part items and miniaturize a device by sealing the periphery of a power device mounting part in resin and mounting a circuit board on a sealing resin surface. SOLUTION: For example, a power transistor chip 1, power transistor mounting part 4, bonding wire 5 and a part of a lead 3 are incorporated in a power module device, and a sealing resin 6 such as epoxy resin is formed into a box shape having no lid. Then, on the rear plane of the sealing resin 6 arc on the bottom plane of a recess of the sealing resin 6, a part of the surface of the lead 3 is exposed, and furthermore, a part of the lead 3 is protruded to the external of the sealing resin 6 to provide electrical connection with the external. On the bottom plane inside the recess of the sealing resin 6, a control board 8 whereupon a control circuit is formed by a circuit component 8A is mounted. From the control board 8, a bonding wire 5A is connected with the surface of the lead 3 exposed on the part of the resin sealed bottom plane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power module device and a method of manufacturing the same, and more particularly to a semiconductor power module device having a structure in which a semiconductor power device and a control circuit thereof are integrated and a method of manufacturing the same. .

[0002]

2. Description of the Related Art A power module is a product in which a power device and a control circuit used for controlling the power device are housed in a single case, and contributes to downsizing of components and reduction of the number of components, so that demand is expanding. doing. Especially,
Demand for semiconductor power modules using semiconductor power devices that output power of about 30 W to 200 W (medium power) is rapidly increasing, especially for inverters and the like, because of their small size and high reliability.

Hereinafter, an outline of a conventional semiconductor power module device will be described with reference to FIG. FIG. 8 shows a top view and a sectional view of a conventional semiconductor power module device. FIG.
FIG. 8A is a top view of a conventional semiconductor power module device before potting resin sealing, and FIG.
Shows a cross-sectional view taken along a dashed line in FIG. 8A.

FIG. 8 (c) is a cross-sectional view taken along a dashed line in FIG. 8 (a) after the potting resin is sealed in FIG. 8 (a). 8A and 8B, the power transistor chip 1 is mounted on a heat spreader 21 made of copper, and the heat spreader 2 is mounted on the heat spreader 2.
1 is mounted on the electrode region 41 on the metal base substrate 31 on the surface of which a wiring pattern including the electrode region 41 is formed via an insulating film 31A.

On the other hand, a control board 80 on which circuit components 85 such as a resistor and a capacitor are mounted on the surface is a resin case 60.
Mounted on the bottom inside. The resin case 60 is formed in a box shape without a lid, and the control board 80
The above-mentioned metal base substrate 31 is attached to a portion other than the mounting portion.

An external connection lead 65 for connecting the inside and the outside of the resin case 60 penetrates through one side surface of the box-shaped resin case 60. A portion of the external connection lead 65 inside the resin case 60 is Part of the surface is exposed for electrical connection.

The electrode region 41 formed on the metal base substrate 31 and the power transistor chip 1 are electrically connected to the control substrate 80 by bonding wires 50.

The control board 80 and the resin case 6
The connection wires 50A are electrically connected to the external connection leads 65 exposed to the inside by using bonding wires 50A. Further, the inside of the box-shaped resin case 60 is filled with a potting resin 90 to form a semiconductor power module device (FIG. 8C).

Next, a method of manufacturing a conventional semiconductor power module device will be described with reference to FIGS.
FIG. 9 is a sectional view showing a main part of a manufacturing process of a conventional power module device.

First, the power transistor chip 1 is mounted on the upper surface of the metal heat spreader 21 by soldering.
Here, the heat spreader 21 is made of a material having good thermal conductivity and electric conductivity such as copper, and is electrically connected to the collector electrode on the back surface of the power transistor chip 1 (FIG. 9).
(A)).

Next, the heat spreader 21 on which the power transistor chip 1 is mounted is mounted on a metal base substrate 31. The metal base substrate 31 is made of a material having good thermal conductivity and electric conductivity like the heat spreader 21. However, when a plurality of power transistor chips 1 are mounted on the metal base substrate 31, It is necessary to independently control the potential on the back surface of the chip. For this reason, an insulating film 31A is formed on the front surface, and an electrode region 41 is formed for each transistor chip.
Is formed so that the back potential of each chip can be controlled independently (FIG. 9B).

On the other hand, a control circuit for controlling the output of the power transistor includes circuit components 85 such as a resistor and a capacitor.
Is soldered to a control board 80 made of glass epoxy or the like (FIG. 9C).

Next, the control board 80 is bonded to a predetermined location on the inner bottom surface of the resin case 60 on which the external connection leads 65 are formed in advance (FIG. 9D). Subsequently, the metal base substrate 31 on which the heat spreader 21 is mounted is mounted in a predetermined space formed on the bottom surface of the resin case 60 (FIG. 9E).

Next, the power transistor 1, the control board 8
The necessary parts of 0 are connected to each other by a bonding wire 50. Further, the control board 80 and the external connection leads 65 inside the resin case 60 are connected by the bonding wires 50A. As a result, necessary electrical connections are obtained (FIG. 8B).

Next, the bonding wires 50, 5
In order to protect the surface of the power transistor chip 1 and the power transistor chip 0A, a potting resin 90 is formed on the entire concave portion in the resin case 60, and a characteristic test is performed to complete the power module device (FIG. 8C). .

[0016]

The above-mentioned conventional semiconductor power module device has the following problems. 1) The power transistor chip 1 is connected to the metal base substrate 31.
The metal base substrate 31 has an epoxy-based insulating film 31A formed on the surface thereof to ensure electrical insulation of each power transistor chip 1. However, even if a filler is mixed, the thermal conductivity of the insulating film 31A is A
It is about two orders of magnitude worse than 1 and Cu, thereby degrading transient heat dissipation characteristics. To compensate for this, the power transistor chip 1 is mounted on a heat spreader 21 made of copper, and the heat spreader 21 is mounted on a metal base substrate 31.

Due to such a configuration, the number of mounted components around the power transistor chip 1 is large, and the price of the components is high. 2) Since the metal base substrate 31 and the control substrate 80 are arranged in the resin case 60 and connected to each other by the bonding wires 50, the metal base substrate 31 and the control substrate 80 are substantially flat enough to allow bonding. It is necessary to arrange it. Therefore, the metal base substrate 31 and the control substrate 80 cannot be stacked and arranged, and the required area increases.

Further, the above-mentioned conventional method for manufacturing a semiconductor power module device has the following problems. 1) The number of components such as a resin case, a metal base substrate, and a control substrate is large, and the manufacturing process is long accordingly. For this reason,
High production price. 2) The process from mounting the power transistor chip 1 to filling the potting resin 90 is long, during which the surface of the power transistor chip 1 is exposed. For this reason,
During the process, the surface of the power transistor chip 1 is often scratched, and the power transistor chip 1 is likely to be defective. 3) An accurate electrical characteristic test of the power transistor chip 1 cannot be performed until the step of forming the bonding wires 50 and 50A is completed. For this reason, electrical characteristic failure of the power transistor chip 1 cannot be removed until the final step, and the failure rate in the final step increases.

The present invention has been made in view of the above problems, and has a small number of parts, a small power module device, a short manufacturing process, high device reliability, and An object of the present invention is to provide a method of manufacturing a power module device, which can remove a defect of a power device generated in a previous process.

[0020]

In order to solve the above problems, in a power module device according to the present invention, a power device, a power device mounting portion having the power device mounted on a surface, and a power device mounting portion are provided. A power device lead having conductivity and formed integrally from the same material, and a control circuit for controlling the power of the power device formed on a circuit board different from the power device mounting portion, The power device and the periphery of the power device mounting portion of the power device mounting portion are sealed inside a sealing resin, and the circuit board is mounted on the sealing resin surface.

The power device mounting part and the power device lead are provided with a plurality of conductive leads formed from the same material as the power device mounting part. The power device electrode and the conductive lead are included in the sealing resin. And a second connecting means for electrically connecting the conductive lead exposed from the sealing resin and the signal terminal of the circuit board.

Further, the sealing resin is formed in a box shape having a concave cross section, and the circuit board is mounted on a bottom surface of the concave portion of the sealing resin. Further, in the method for manufacturing a power module device according to the present invention, a step of mounting a power device on a power device mounting portion formed from a conductive thin plate; and a step of mounting the power device on a plurality of conductive leads formed from the conductive thin plate. Electrically connecting the power device, resin-sealing the power device to form a resin-sealed body, and a circuit board on which a control circuit for controlling the power of the power device is formed on the resin-sealed body. And a step of electrically connecting the conductive leads to a desired portion of the circuit board.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A power module device according to a first embodiment of the present invention will be described with reference to FIG.
This will be described in detail with reference to FIG.

FIG. 1 is a sectional view of a semiconductor power module device. In FIG. 1, a power transistor chip 1 (power device) is mounted on a surface of a power transistor mount portion 4 (power device mounting portion) formed of a thin metal plate such as copper. Power transistor chip 1
From then on, the bonding wire 5 is connected to the lead 3 to establish electrical continuity.

The power transistor chip 1,
A sealing resin 6 such as an epoxy resin or the like is formed in a box shape without a lid, in which the power transistor mount portion 4, the bonding wires 5, and a part of the leads 3 are incorporated.

On the back surface of the box-shaped sealing resin 6 without the lid, the back surface of the power transistor mount 4 is provided.
The lead 3 is provided on the bottom surface of the box-shaped sealing resin 6 having no lid.
A part of the surface of the lead 3 is exposed, and a part of the lead 3 is configured to protrude outside the sealing resin 6 so that an electrical connection with the outside can be obtained.

A control board 8 on which a control circuit is formed by circuit components 8A is mounted on the bottom inside the concave portion of the box-shaped sealing resin 6 without a lid. Is connected to the surface of the lead 3 exposed on a part of the bottom surface of the sealing resin.

A potting resin 9 such as a silicone resin is filled in the recess of the box-shaped sealing resin 6 which covers the control board 8 and the bonding wires 5A.

Here, one or a plurality of power transistor chips 1 can be sealed in one sealing resin 6 as needed. Even when a plurality of power transistor chips 1 are sealed, as shown in FIG.
Are formed separately, the power transistor chip 1 can be mounted in the sealing resin 6 while being electrically insulated. However, in this case, in the form as shown in FIG. 2C, the back surfaces of the plurality of power transistor mounts 4 are electrically connected to each other by the radiation fins usually provided on the lower surfaces. Such inconvenience is caused by forming the sealing resin 6 thinly on the back surface of the power transistor mount,
This can be solved by securing electrical insulation within a range that does not significantly impede heat dissipation.

According to the power module device according to the first embodiment of the present invention described above, 1) the power transistor chip 1 is mounted on the power transistor mount 4, but a plurality of power transistor chips are used. However, it is easy to separate a plurality of power transistor mounts 4 in the same sealing resin 6 and to electrically insulate and fix them. For this reason, it is possible to secure electrical insulation and to secure good transient heat dissipation characteristics with a substantially small number of components. 2) The electrical connection between the power transistor chip 1, the power transistor mount 4 and the control board 8 can be made via the leads 3. For this reason, it is not necessary to arrange them on the same surface, and they can be arranged by being stacked inside and above the sealing resin 6. Therefore, the required area is small.

Next, a method of manufacturing the power module device according to the first embodiment will be described in detail with reference to FIG. FIG. 2 is a process top view and a process cross-sectional view of the manufacturing process of the semiconductor device according to the first embodiment of the present invention.

FIG. 2A shows a top view of a state in which the power transistor chip 1 is mounted on the power transistor mounting portion 4 of the lead frame 2 by using solder (not shown) and connected to the power device leads 3A by bonding wires 5. FIG. Here, the power transistor mount portion 4 in the lead frame 2 is formed by supporting portions 2A on both sides of the lead frame 2 formed so as to extend in a belt shape.
Is fixed on the lead frame 2 by a mounting portion lead 2B extending inward from the mounting portion lead 2B.
A power device lead 3A to be a power module lead and a control board lead 3B are formed on both sides of the power module. Here, the control board leads 3B are formed for electrical connection to the control board 8 to be mounted in a later step.

FIG. 2B is a cross-sectional view taken along a dashed line in FIG. 2A. Here, the power transistor mount 4 is formed to be thicker than other parts of the lead frame 2 in order to improve the heat diffusion.

Next, the power transistor chip is resin-encapsulated with epoxy resin so that the external shape becomes a box shape without a lid by an ordinary resin encapsulation technique, and unnecessary portions of the lead frame are cut and removed. FIG. 2C is a cross-sectional view of the power transistor portion after resin sealing. Here, the resin sealing is performed so that the leads 3 can be easily bonded in a later step.
Is performed so that a part of the surface of the resin is exposed from the inner bottom surface of the box-shaped sealing resin 6 concave portion without the lid. In order to sufficiently dissipate heat in the power transistor chip 1, the back surface of the power transistor mount portion 4 of the power transistor chip 1 is also sealed in a box-like shape without a lid so that it can directly contact a heat sink outside the power module device. It is formed so as to be exposed from the back surface of the sealing resin 6.

Next, the control board 8 on which the circuit components 8A are mounted in advance is formed on the bottom surface of the concave portion of the sealing resin formed in a box shape without a lid.
Adhesively fixed. Further, a desired portion of the control board 8 is connected to the surface 3A of the lead 3 exposed from the surface of the sealing resin 6 by a bonding wire 5A to make necessary electrical connection.

Next, by filling the concave portion of the sealing resin 6 with a potting resin 9 such as a silicone resin, the control board 8 and the bonding wires 5A are protected, and a power module device can be obtained (FIG. 1D). ).

According to the method of manufacturing the power module device of the first embodiment of the present invention, the following effects can be obtained. That is: 1) The number of parts is smaller than that of the conventional power module device. That is, a part of the role of the resin case and the role of the metal base of the conventional power module device is a sealing resin, and the lead frame plays the role of the conventional lead, heat spreader, and the role of the metal-based wiring, The number of parts is reduced as a whole. In addition, since the step of mounting the heat spreader on the metal base substrate and the step of bonding the metal base substrate to the case are not required, the manufacturing process is short. 2) Since resin sealing is performed immediately after mounting and wire bonding of the power transistor chip 1, the number of steps in which the surface of the power transistor chip 1 is exposed is small,
There is less danger of scratching the surface. Therefore, there is little possibility that a failure of the power transistor chip 1 occurs during the process. 3) After the resin sealing step, it is possible to inspect the electric characteristics of the power transistor chip 1 before mounting the control substrate, and it is possible to remove electric characteristic defects during the process. For this reason, the defective rate in the final step can be significantly reduced, and the manufacturing cost can be significantly reduced.

Next, a modified example of the power module device according to the first embodiment of the present invention will be described in detail with reference to FIGS. 3, 4, and 5, taking a semiconductor power module as an example.

FIG. 3 is a sectional view showing a first modification of the semiconductor power module device according to the first embodiment of the present invention. In FIG. 3, the same portions as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. In the modified example of the semiconductor power module device shown in FIG. 3, the control board 8 and the leads 3 are electrically connected by soldering a metal jumper wire 5B instead of the bonding wire 5A. By using such a metal jumper 5B, in addition to the above-described effects of the power module device according to the first embodiment of the present invention, when the surface of the lead 3 is deteriorated due to oxidation or the like. Also, there is an effect that sufficient electrical conduction can be reliably obtained.

FIG. 4 is a sectional view showing a second modification of the semiconductor power module device according to the first embodiment of the present invention. In FIG. 4, the same portions as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. In the modification of the semiconductor power module device shown in FIG. 4, the back surface of the power transistor mount 4 is not exposed to the back surface of the sealing resin 6 but is sealed in the sealing resin 6.

By adopting such a form, in addition to the effects described for the power module device according to the first embodiment of the present invention, the exposed back surface of the power transistor mount 4 is prevented from being deteriorated. You can also
It is possible to prevent water from entering from the interface between the power transistor mount 4 and the sealing resin 6. In addition, by adopting such an embodiment, the power transistor mount 4
Since the insulating layer of the sealing resin 6 is formed on the back surface,
Even if conductive radiating fins are brought into contact with the back surface of the sealing resin, there is no electrical conduction, and electrical control of the power transistor mount can be performed independently of the radiating fins.

FIG. 5 is a sectional view showing a third modification of the semiconductor power module device according to the first embodiment of the present invention. In FIG. 5, the same portions as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. In the modified example of the semiconductor power module device shown in FIG. 5, the back surface of the power transistor mount portion 4 is not exposed to the back surface of the sealing resin 6 and is sealed in the sealing resin 6 as in the second modified example. Has been stopped. In the third modification, a metal plate-shaped heat radiation fin 35 larger than the power transistor mount portion 4 is placed on the back surface of the power transistor mount portion 4 with a thin sealing resin 6 interposed therebetween. The back surface of 35 is exposed on the back surface of the sealing resin 6. By taking such a form, in addition to the effects described in the above second modification,
By incorporating the radiation fins 35 into the power module, stable radiation characteristics can be obtained.

(Second Embodiment) Next, a power module device according to a second embodiment of the present invention will be described in detail using a semiconductor power module as an example with reference to FIG.

FIG. 6 is a sectional view of a semiconductor power module device according to a second embodiment of the present invention. In FIG.
The same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. In FIG. 6, as in the first embodiment shown in FIG. 1, the lead frame 2 shown in FIG. 1A is used to mount the power transistor mount 4 as shown in FIG. The power transistor chip 1 is mounted and connected by bonding wires 5. However, in the second embodiment of the present invention, unlike the first embodiment, the concave portion is not formed in a box shape without a lid at the time of resin sealing,
The surface is formed flat.

Further, similarly to the power module device according to the first embodiment, the control substrate 8 is adhered to the surface of the sealing resin and connected by the bonding wires 5A. Further, the surface of the sealing resin 6 is potted with a highly viscous potting resin 9 such as an epoxy resin or a silicone resin,
A power module device is formed.

In the second embodiment of the present invention, in addition to the effects described in the first embodiment, since the surface of the mold resin is formed on a flat surface without a concave portion,
There is an effect that the releasability from the mold after the resin molding is good and the dimensional accuracy of the resin sealing body is also good. In addition, there is an advantage that the amount of the sealing resin is small and the module can be easily miniaturized.

Next, a power module device according to a third embodiment of the present invention will be described in detail using a semiconductor power module as an example with reference to FIG. FIG. 7 is a sectional view of a power module device according to the third embodiment of the present invention.

In FIG. 7, the method of forming the sealing resin 6 is substantially the same as that of the power module device according to the first embodiment shown in FIG. 1, except that the size of the box-shaped concave portion without the lid is small. This is the same, and the same parts as those in FIG.

In FIG. 7, the size of the control board 8 is larger than that of the first embodiment, and is formed substantially equal to the bottom area of the sealing resin 6. The circuit component 8A is
The control substrate 8 is mounted on a portion corresponding to the concave portion of the sealing resin 6 on the back surface of the control substrate 8, and the control substrate 8 and the sealing resin 6 are fixed to each other by bonding, screwing, or the like.

In the power module device according to the third embodiment of the present invention, in addition to the effects described in the device according to the first embodiment of the present invention, since the potting resin is not used, The effect is that the surface of the device is robust and resistant to external impact.

In each of the above embodiments and modifications thereof, the case where only the power device is mounted and sealed in the sealing resin has been described. However, the present invention is not limited to this. Alternatively, another device such as a part of a control circuit of a power device may be sealed in the same resin.

Further, in each of the above embodiments and the modifications thereof, the power transistor mount portion of the lead frame is formed flat and thick for heat dissipation, but the present invention is not limited to this. Instead, the thickness may be the same as that of the other parts of the lead frame, and if necessary, a recess may be formed in the power transistor mount.

In the above embodiments, the potting resin is a silicone resin. However, the potting resin may be a thixotropic silicone gel, silicone rubber, or epoxy.

[0054]

As described above, by using the present invention, a power module device having a small number of components and a small size, and a power module device capable of shortening the process and selecting defects in a previous process. Can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a semiconductor power module device according to a first embodiment of the present invention.

FIG. 2 is a process top view and a process cross-sectional view of a manufacturing process of the semiconductor device according to the first embodiment of the present invention.

FIG. 3 shows a first modification of the semiconductor power module device according to the first embodiment of the present invention.

FIG. 4 shows a second modification of the semiconductor power module device according to the first embodiment of the present invention.

FIG. 5 shows a third modification of the semiconductor power module device according to the first embodiment of the present invention.

FIG. 6 is a sectional view of a power module device according to a second embodiment of the present invention.

FIG. 7 is a sectional view of a power module device according to a third embodiment of the present invention.

FIG. 8 shows a top view and a sectional view of a conventional semiconductor power module device.

FIG. 9 is a process sectional view of a manufacturing process of a conventional semiconductor power module device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Power transistor chip 2 ... Lead frame 2A ... Support part (lead frame) 2B ... Mount part lead 3 ... Lead (part of lead frame) 3A ... Power device lead 3B: Lead for control board 35: Heat radiation fin 4: Power transistor mount (part of lead frame) 5, 5A: Bonding wire 5B: Metal jumper wire 6: Sealing Resin 7: concave portion (upper part of sealing resin) 8: control board 8A: circuit component 9: potting resin 21: heat spreader 31: metal base substrate 31A: insulating film (On the metal base substrate 31) 41: electrode region (on the insulating film 31A) 50, 50A: bonding wire 60: resin case 65: outside Connection lead 80 ... control board 85 ... circuit parts 90 ... potting resin

Claims (4)

[Claims] 1. A power device, a power device mounting portion having the power device mounted on a surface thereof, and a conductive power device lead integrally formed with the power device mounting portion and formed from the same material; A control circuit for controlling the power of the power device formed on a circuit board different from the power device mounting portion, wherein the power device and the power device mounting portion of the power device mounting portion are surrounded by a sealing resin. A power module device sealed inside, wherein the circuit board is mounted on the surface of the sealing resin. 2. A power supply device comprising: a plurality of conductive leads formed by processing the same material as the power device mounting portion and the power device lead; and an electrode of the power device and the conductive lead included in the sealing resin. And a second connection means for electrically connecting the conductive lead exposed from the sealing resin and a signal terminal of the circuit board. 2. The power module device according to 1. 3. The power module device according to claim 2, wherein the sealing resin is formed in a box shape having a concave cross section, and the circuit board is mounted on a bottom surface of the concave portion of the sealing resin. 4. A step of mounting a power device on a power device mounting portion formed from a conductive thin plate; a step of electrically connecting the power device to a plurality of conductive leads formed from the conductive thin plate; A step of resin-sealing the power device to form a resin-sealed body; a step of mounting a circuit board on which a control circuit for controlling the power of the power device is formed on the resin-sealed body; Electrically connecting a desired portion of the circuit board to a desired portion of the circuit board.