JP2002164500A - Semiconductor module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a built-up structure so as to achieve improvement in assembly and reliability and cost reduction keeping advantages of two-tier system wherein a control circuit and a power circuit are arranged up and down in a package. SOLUTION: In a semiconductor module sealed with a silicon gel injected into the package wherein the power circuit 5 mounting a power semiconductor (IGBT) on a power circuit board 5a and the control circuit 6 mounting circuit parts on a print circuit board 6a are built in a package comprising a metal base plate 1 and a built-in terminal surrounding case 2, the power circuit board is soldered on the metal base plate and other printed board is formed in U- shape, the printed board is arranged at the bottom of the surrounding case and put on support blocks 9 with relay terminals molded in and supported, after that the power circuit and the control circuit are wired via the relay terminal 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intelligent power module (Inte
More specifically, the present invention relates to an assembly structure of a semiconductor device for an integrated power module.

[0002]

2. Description of the Related Art As the above-mentioned intelligent power module, there is known an intelligent power module having a structure in which a main circuit block and a control circuit are housed in a package thereof. FIGS. 4 and 5 show a conventional assembly structure. In each of the figures, 1 is a metal base plate for heat radiation (copper base), 2 is an outer case (resin molded product) integrated with a terminal, and 3 is a main circuit terminal (an external lead-out terminal for input and output to the main circuit). Reference numeral 4 denotes a control terminal (externally derived terminal for the control circuit), 5 denotes a power circuit, 6 denotes a control circuit, and 7 denotes a bonding wire of an internal wiring.
Here, the power circuit 5 is mounted on the power circuit board 5a.
A power semiconductor element 5b such as GBT and a freewheeling diode 5c are mounted. The power circuit board 5a is formed by directly bonding a copper circuit pattern on the upper surface of a ceramic plate such as alumina or aluminum nitride and directly bonding a copper layer on the lower surface. Direct Bond Copper substrate is adopted. On the other hand, the control circuit 6 has a configuration in which a drive IC 6b for driving the power element 5b and various circuit components are mounted on a printed board 6a.

In the example shown in FIGS. 4A and 4B, the power circuit 5 and the control circuit 6 are mounted on the upper surface of the metal base plate 1 on the same surface. Assemble with First, the power circuit 5 is
The control circuit 6 attaches the printed circuit board 6a to the metal base plate 1 with an adhesive by soldering the copper layer a to the metal base plate 1 with the copper layer downward. Subsequently, wires 7 are bonded and connected between the power circuit 5 and the control circuit 6 to provide internal wiring. Next, after covering the metal base plate 1 with the terminal-integrated outer case 2 and joining with an adhesive, between the inner lead portion 3a of the main circuit terminal 3 and the circuit pattern of the power circuit board 5a, and The control terminal 4 and the circuit pattern of the control circuit board 6a are soldered. Then, a gel filler (for example, silicone gel) is injected into the package to seal the main circuit block 5 and the control circuit 6, and finally, the outer case 2 is covered with an upper lid (not shown).

On the other hand, the example shown in FIG. 5 has a configuration in which a power circuit 5 and a control circuit 6 are incorporated in a two-story type in a package. Here, the power circuit 5 is soldered on the metal base plate 1 as in FIG.
Means that the printed circuit board 6a is
The outer case 2 having a terminal integrated type is superposed on the metal base plate 1 on which the power circuit 5 is mounted, and the main circuit terminal 3 and the circuit pattern of the power circuit board 5a are soldered. After that, the resin frame 8 is placed on the power circuit 5.
a, the relay terminal block 8 including the relay terminal 8b is overlapped and soldered to the relay terminal 8b and the circuit pattern.
The control circuit 6 is mounted on the terminal block 8, and in this state, the printed circuit board 6a is soldered to the relay terminals 8b and the control terminals 4. Thereafter, a gel-like filler is injected into the package in the same manner as described with reference to FIG.

[0005]

The conventional semiconductor device having the assembly structure shown in FIG. 4 or 5 has the following problems. That is, (1) In the configuration shown in FIG. 4, the package occupies a large area and the semiconductor device becomes large, and the power circuit 5 and the control circuit 6 are mounted on the metal base plate 1 in the assembling process. If a defect of a circuit component mounted on the printed circuit board 6a of the control circuit 6 is found in the intermediate test of the product, the printed circuit board 6a has already been fixed to the metal base plate 1 with an adhesive, and only the printed circuit board 5a has been fixed. From the metal base plate 1 to replace defective parts is impossible.
The intermediate assembly of the product must be discarded, resulting in a large loss of parts.

(2) In the configuration shown in FIG. 5, a two-story system is employed, so that a semiconductor device is reduced in size and size, and a defect is found in a mounted part of a control circuit in an intermediate test performed during an assembly process. In this case, there is an advantage that the control circuit can be easily replaced with a non-defective one. On the other hand, when the control circuit 6 having a rectangular printed circuit board is mounted above the power circuit 5 in the package, the power circuit 5 becomes Since it is hidden behind the control circuit 6 and cannot be seen from the outside, the structure inside the package cannot be checked. In addition, in the step of injecting the gel filler into the package, only a narrow gap remains between the outer case 2 and the peripheral edge of the printed circuit board 6a of the control circuit 6, and it takes time to inject the filler. In addition, when a heat cycle is applied in the actual use state of the semiconductor device, the power circuit 5 has almost no problem because the entire surface of the ceramic substrate is joined to the metal base plate 1. The printed circuit board 6a of the control circuit 6 having a rectangular shape mounted and supported on the terminal block 8 is easily affected by a heat cycle, and therefore, a large stress is applied to the solder joint with the terminal and the solder joint is separated. May cause troubles such as

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to solve the above-mentioned problems and to improve the ease of assembly while taking advantage of a two-story system in which a control circuit and a power circuit are arranged vertically in a package. It is an object of the present invention to provide an improved semiconductor device assembly structure for improving reliability, and reducing cost.

[0008]

According to the present invention, a metal base plate for heat radiation and an external connection terminal of a main circuit and a control circuit are arranged on the upper surface of a peripheral portion of a resin case. A semiconductor device in which a power circuit and a control circuit are incorporated in a package formed of a terminal-integrated outer case, and each of the circuit blocks is sealed with a gel filler injected into the package. The power circuit board is equipped with power semiconductor elements, and the control circuit is configured with control circuit components mounted on a printed circuit board.The power circuit board is soldered and mounted on a metal base plate in the same way as before. On the other hand, the printed circuit board of the control circuit has a U-shape, and the printed circuit board is arranged in a two-story manner above the power circuit along the inner peripheral side of the outer case. Above, constitutes subjected to internal wiring between the power circuit, and a control terminal (claim 1).

According to this structure, the printed circuit board of the control circuit disposed above the power circuit is formed into a U-shape while taking advantage of the features of the two-story system, so that the printed circuit board is disposed on the bottom side in the package through the center opening. The assembly status of the arranged power circuit can be visually checked from the outside, and the gel-like filler can be smoothly injected into the package to every corner. In addition, the U-shaped printed circuit board has a smaller amount of deformation caused by a heat cycle than a rectangular printed circuit board, thereby reducing stress on a soldered portion and improving reliability. In addition, when multiple U-shaped printed circuit boards are taken from a large-sized material board, if the U-shaped pattern corresponding to each printed circuit board is patterned and cut so as to be intertwined on the left and right, the cut of the board Almost no broken material is generated, so that the U-shaped printed circuit board can be efficiently multi-faced using the board material with little waste, and the cost can be reduced.

Further, according to the present invention, the internal wiring structure between the power circuit and the control circuit in the above configuration can be realized in the following manner. (1) The outer case is provided with a support block with relay terminals that rises from the bottom side so as to face the printed circuit board of the control circuit incorporated in the package, and the support block is used as a support base and the control circuit is mounted thereon. After mounting the printed circuit board, the power circuit and the control circuit are interconnected by wire bonding via a relay terminal (Claim 2). Specifically, the support block with the relay terminal is provided. When the outer case is molded, the L-shaped relay terminal is inserted and molded integrally (claim 3).

As described above, by integrally forming the support block on the bottom side of the outer case, the control circuit can be mounted and supported, and the assembling process can be simplified.
By forming the relay terminal in the support block by insert molding, the internal wiring between the power circuit and the control circuit can be easily performed. (2) As an alternative to the support block with the relay terminal of the preceding paragraph (1), a support block integrally formed with the power element driving IC is formed upright on the bottom side of the outer case facing the control circuit board. There is a configuration in which a control circuit is mounted on the support block and leads of the IC are connected to the power circuit and the control circuit. In this configuration, a dual-in-line package type IC is used as a power element driving IC, and the package of the IC is placed in an upright posture, and leads are pulled out vertically from the side surface of the package. One is straightened upward and the other is bent into an L-shape, and then, when molding the outer case, the IC is insert-molded integrally with the support block (claim 5).

According to this structure, the position of the IC is closer to the power semiconductor element mounted on the power circuit, and the wiring length between the two is shorter than in the case where the IC is mounted on a two-story printed circuit board. Thereby, the influence of the wiring inductance can be suppressed low, and malfunction of the IC can be prevented.
Further, since the resin-sealed packaged IC is further molded integrally with the support block, it is more resistant to heat and moisture than the configuration in which the bare chip IC is mounted on a printed circuit board as shown in FIGS. Reliability can be ensured. Further, since the IC is separated from the printed circuit board of the control circuit and placed separately, the required area of the printed circuit board can be reduced correspondingly.

(3) As still another embodiment, an auxiliary board is formed by forming a lead extending sideways from the board on the power circuit board and forming a lead drawn from a circuit pattern on the power circuit board on the upper surface of the board. The board is formed integrally, the power circuit board is mounted on the metal base plate by soldering, and then the auxiliary board is bent and erected at a right angle. There is a configuration for connecting to a printed circuit board of a control circuit. In addition, this auxiliary substrate does not have a copper layer on the back side, and a scribe line is formed in advance along a boundary between the power substrate and the auxiliary substrate, and the auxiliary substrate is bent upright at a right angle while the leads are connected to stand. Be able to do it. In addition, the auxiliary board that has been erected as described above is fitted and held along a support block that is integrally formed on the bottom side of the outer case (claim 7).

With the above configuration, the support of the control circuit and the internal wiring can be performed simultaneously using the auxiliary substrate and the leads formed on the substrate. Also, by directly connecting the lead of the auxiliary board to the printed circuit board of the other party, the bonding wires between the power circuit and the control circuit or the relay terminal described in (1) above are omitted, and the internal wiring is greatly reduced. Can be simplified.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below with reference to the embodiments shown in FIGS. In each embodiment, the same reference numerals are given to members corresponding to FIGS. 4 and 5, and the description thereof is omitted. [Embodiment 1] FIGS. 1A and 1B are block diagrams of an embodiment according to claims 1 to 3 of the present invention. In this example,
The board 5a of the power circuit 5 is mounted on the upper surface of the metal base plate 1 by soldering as in FIG. On the other hand, the printed circuit board 6a of the control circuit 6 has a U-shape as shown. The printed circuit board 6 a is placed on a relay terminal block 9 integrally formed on the bottom side of the outer case 2 along the inner peripheral side of the outer case 2, and two stories above the power circuit 5. It is arranged so that it is soldered to the relay terminal 9a of the relay terminal block 9 which passes through the through hole of the printed board 6a at this position. A drive IC 6b (bare chip) for the power semiconductor elements 5b mounted on the power circuit 5 is mounted on the printed circuit board 6a so as to face each power semiconductor element 5b. As a result, the distance between the power semiconductor element 5b and the driving IC 6b is reduced, so that malfunction of the driving IC 6b can be prevented.

Here, when the U-shaped printed circuit board 6a is to be formed from a large-sized board material plate in a multi-faced manner, the U-shaped patterns corresponding to the individual printed boards are formed on the board material board so as to be intertwined with each other on the left and right sides. And cut it. As a result, hardly any broken material is generated due to the cutting of the substrate, whereby the U-shaped printed circuit board can be efficiently multi-faced using almost no waste of the substrate material, and the cost can be reduced.

The above-mentioned relay terminal block 9 is formed at the same time when the outer case (resin molded product) 2 is molded, and an L-shaped relay terminal 9a is insert-molded in the block. I have. The semiconductor device having the above configuration is assembled in the following order. First, the substrate 5a of the power circuit 5 is mounted on the upper surface of the metal base plate 1 by soldering. Subsequently, the terminal-integrated outer case 2 is put on and adhered to the metal base plate 1, and in this state, between the circuit pattern formed on the substrate of the power circuit 5 and the main circuit terminal 3, and A bonding connection is made between the relay terminal block 9 and the relay terminal 9 a by the wire 7. Next, after placing the U-shaped printed circuit board 6a of the control circuit 6 on the relay terminal block 9, soldering is performed between the relay terminal 9a projecting from the upper surface of the substrate and the control terminal 4, or Connection is made using a conductive adhesive. Thereafter, a gel filler such as silicone gel is injected into the outer case 2 from the upper surface side of the package to seal the power circuit 5 and the control circuit 6. At this time, the gel filler flows into the back side of the U-shaped printed board 6a through the central opening 6a-1 to fill the corners. Finally, an upper cover (not shown) is put on the outer case 2 and bonded.

As can be seen from the above description, even during the assembly in which the power circuit 5 and the control circuit 6 are incorporated in the package, the power semiconductor element 5b and the like in the power circuit 5 can be passed through the central opening 6a-1 of the printed circuit board 6a. You can visually check the mounting status of. The U-shaped printed circuit board 6a is more easily bent than the rectangular printed circuit board shown in FIG. 5, and the peripheral edge of the printed circuit board 6a is placed on the relay terminal block 9 so that the relay terminal 9a and the control terminal Soldering with No. 4 also has the effect of reducing the stress applied to the solder joint due to the heat cycle.

[Embodiment 2] FIGS. 2 (a) to 2 (c) show an embodiment corresponding to claims 4 and 5 of the present invention, which is an applied embodiment of the embodiment 1 described above. In this embodiment, the basic assembling structure is the same as that of the first embodiment. The power circuit 5 and the control circuit 6 are mounted in a package in a two-story system, and the printed circuit board 6a of the control circuit 6 has a U-shape. However, in this embodiment, the following support structure is employed instead of the relay terminal block 9 in FIG.

That is, in the first embodiment, the driving IC (bare chip) 6b for the power semiconductor element 5b is mounted on the printed circuit board 6a of the control circuit 6, but in this embodiment, the driving IC shown in FIG. A package type IC 6c sealed with resin as shown in the figure is used, and is not mounted on the printed circuit board 6a, but is mounted on the support block 10 integrally formed on the bottom side along the inner peripheral side of the outer case 2. Then, insert molding is performed in a posture standing upright as shown in the figure. In the package type IC 6c, one of the IC leads 6c-1 and 6c-2 extending vertically from the side surface of the package is formed by straightly extending one lead 6c-1 upward and the other lead 6c-2.
Is bent into an L-shape, and its tip is directed toward the inside of the outer case 2.

When assembling the semiconductor device, the power semiconductor element 5b mounted on the substrate 5a of the power circuit 5 and the lead of the IC 6c are mounted on the metal base plate 1 on which the power circuit 5 is mounted with the surrounding case 2 covered. 6c-2 is connected by bonding with a wire 7. Thereafter, the printed circuit board 6a of the control circuit 6 is placed on the support block 10 integrated with the IC 6c as a support base, and the leads 6c-1 of the IC 6c protruding toward the upper surface of the board through the through holes of the board are printed. It is connected to the circuit pattern of the substrate 6a by soldering or using a conductive adhesive. The driving IC 6c is arranged at the same position as in the embodiment of FIG.

According to the above configuration, the position of each IC 6c is closer to the power semiconductor element 5b mounted on the power circuit 5 as compared with the assembly structure of FIG. 5 in which the bare chip IC 6b is mounted on the two-story printed circuit board 6a. As a result, the length of the wiring between them can be shortened, whereby the influence of the wiring inductance can be suppressed to a low level, and malfunction of the IC can be prevented. Further, by adopting a double-molded structure in which the resin-sealed package type IC 6c is insert-molded in the support block 10, compared with a configuration in which a bare chip IC is directly mounted on the printed circuit board 6a as shown in FIGS. ,heat,
High reliability against moisture can be secured. Furthermore, IC6
By separating c from the printed circuit board 6a of the control circuit 6, it is possible to reduce the required area of the printed circuit board 6a and widen the central opening 6a-1 accordingly.

Embodiment 3 FIGS. 3A to 3C show an embodiment corresponding to claims 6 and 7 of the present invention. In this embodiment, an auxiliary substrate 5d is formed on a substrate 5a of the power circuit 5 so as to be connected to the ceramic substrate and extends laterally. The upper surface of the auxiliary substrate 5d has a power circuit substrate 5a.
5 for internal wiring to be pulled out from the board and connected to the control circuit
d-1 is patterned. The tip of the lead 5d-1 protrudes forward from the peripheral edge of the auxiliary substrate 5d. A copper layer is not provided on the back side of the auxiliary substrate 5d, and a scribe line is formed along the boundary with the power circuit substrate 5a. The auxiliary substrate 5d can be divided at the scribe line 5e while the lead 5d-1 is connected.

As shown in FIG. 3 (c), the inner case 2 has a width corresponding to the auxiliary substrate 5d on the inner peripheral bottom side thereof, and the auxiliary substrates 5a
The support block 11 in which the engaging claws or the engaging grooves are formed so as to be held in the upright posture by inserting the support case is formed at the same time when the outer case is formed. Then, in the assembly process of the semiconductor device, the substrate 5a of the power circuit 5 is mounted on the metal base plate 1 as shown in the figure and soldered, and then the auxiliary substrate 5d is bent along the scribe line 5e to stand upward. After the surrounding case 2 is put on the metal substrate 1, the auxiliary substrate 5d, which has been raised as described above, is inserted into its claw or engagement groove along the support block 11 and held in the upright posture. Next, in order to support the control circuit 6 in a two-story manner, the printed circuit board 6a is placed on the support block 11 as a support base, and the tips of the leads 5d-1 patterned on the auxiliary board 5d in this state. And printed circuit board 6
a is soldered.

According to the above configuration, the internal wiring between the power circuit 5 and the control circuit 6 is directly connected to the other side of the power circuit board 5a via the leads 5d-1 formed on the auxiliary board 5d by patterning. The connection between the power circuit 5 and the control circuit 6 can be omitted by using a bonding wire or the relay terminal 9a (see FIG. 1) described in the first embodiment. The structure is greatly simplified.

[0026]

As described above, according to the structure of the present invention, the following effects can be obtained. The power circuit board is mounted on a metal base plate, and the printed circuit board has a U-shape, and is placed above the power circuit along the inner circumference of the outer case, and then the power circuit and control According to the configuration of claim 1 in which the internal wiring is provided between the circuit and the external lead-out terminal, (a) the semiconductor device can be reduced in size and size.

(B) It is possible to visually check the status of the power circuit arranged on the bottom side of the package through the central opening of the substrate. (c) It becomes easier to inject the gel filler into the package. (d) The stress is reduced to the soldered portion of the printed circuit board by the heat cycle, and the reliability is improved.

(E) When multiple U-shaped printed circuit boards are formed from a substrate material, the U-shaped printed circuit boards are efficiently patterned by patterning the U-shaped patterns corresponding to the individual printed circuit boards so as to be intertwined with each other on the right and left sides. Can be multi-faceted well. Also, an L-shaped casting terminal is inserted into a support block that stands from the bottom side of the outer case facing the substrate of the control circuit to be integrally formed with the outer case, and the control circuit is mounted on the support block. The power circuit and the control circuit are interconnected via the relay terminal after being mounted. According to the configurations of the claims 2 and 3, (a) the printed circuit board is mounted on the support block with the relay terminal. And the internal wiring between the power circuit and the control circuit can be easily performed at the same time via the relay terminal in this state.

A support block integrated with a dual-in-line-package-type power element driving IC is formed on the bottom side of the outer case facing the control circuit board. After placing the control circuit on the
According to the configuration of the fourth or fifth aspect, the lead drawn from the IC is connected to the power circuit and the control circuit. (A) The position of the IC approaches the power semiconductor element mounted on the power circuit, and the wiring length between the two is reduced. Shorter, which reduces the effect of wiring inductance.

(B) By integrally molding the package type IC with the support block, higher reliability against heat and moisture can be ensured as compared with a configuration in which a bare chip IC is mounted on a printed circuit board. (c) Since the IC is separated from the printed circuit board and placed separately, the required size of the printed circuit board can be reduced.

Further, on the power circuit board of the power circuit,
An auxiliary substrate extending sideways from the substrate and patterned with leads on the upper surface of the substrate is integrally formed, and after mounting the power circuit board on the metal base plate, the auxiliary substrate is bent and erected. According to the configuration of the sixth or seventh aspect, the auxiliary substrate is fitted and held along with a support block integrally formed on the bottom side of the outer case. (A) The auxiliary substrate and pattern formation on the substrate The support of the control circuit and the internal wiring can be performed at the same time by using the formed leads.

(B) By connecting the lead of the auxiliary board directly to the printed circuit board of the other party, the bonding wires or relay terminals are omitted between the power circuit and the control circuit, and the internal wiring is greatly simplified. I can do it.

[Brief description of the drawings]

FIG. 1 is an assembly structural view of a semiconductor device according to a first embodiment of the present invention, in which (a) is an exploded perspective view, and (b) is a perspective view in an assembled state.

FIGS. 2A and 2B are assembly structural views of a semiconductor device according to a second embodiment of the present invention, wherein FIG. 2A is an exploded perspective view, FIG. 2B is a sectional view of a main part in an assembled state, and FIG. Front view

FIGS. 3A and 3B are main part configuration diagrams of a semiconductor device according to a third embodiment of the present invention, wherein FIGS. 3A and 3B are a plan view and a side view, respectively, showing a state where a power circuit board is mounted on a metal base plate; Figure,
(c) is a cross-sectional view of main parts in the assembled state mounted on the package.

FIG. 4 is an assembly structure diagram of a conventional semiconductor device, and FIG.
Is an exploded perspective view, and (b) is an assembled perspective view.

5A and 5B are an exploded perspective view and an exploded perspective view of the semiconductor device of the conventional example different from FIG. 4, and FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal base plate 2 Surrounding case 3 Main circuit terminal 4 Control terminal 5 Power circuit 5a Power circuit board 5b Power semiconductor element 5d Auxiliary board 5d-1 Lead 5e Scribe line 6 Control circuit 6a Printed board 6c Package type IC 6c-1, 6c-2 IC lead 7 Bonding wire 9 Support block with relay terminal 9a Relay terminal 10, 11 Support block

Claims (7)

[Claims] A power circuit and a control circuit are provided in a package comprising a metal base plate for heat radiation and a terminal-integrated outer case in which a main circuit and an external lead-out terminal of a control circuit are arranged on a peripheral portion of a resin case. And a semiconductor device in which each of the circuit blocks is sealed with a gel filler injected into a package, wherein the power circuit has a power semiconductor element mounted on a power circuit board, and the control circuit has a control circuit mounted on a printed circuit board. In the configuration where components are mounted, the power circuit board is mounted on a metal base plate, and the printed circuit board has a U-shape, and it is located above the power circuit along the inner circumference of the outer case. A semiconductor device, wherein an internal wiring is provided between a power circuit and an external lead-out terminal of a control circuit after being arranged. 2. A semiconductor device according to claim 1, further comprising: a support block with a relay terminal, which stands from the bottom side of the outer case and faces the control circuit board, and mounts the control circuit on the support block. And a power circuit and a control circuit are interconnected via a relay terminal. 3. The semiconductor device according to claim 2, wherein the support block with a relay terminal is formed integrally with the surrounding case by inserting an L-shaped relay terminal. 4. A semiconductor device according to claim 1, further comprising: a support block integrated with the power element driving IC at a bottom side of the outer case facing the printed circuit board of the control circuit;
A semiconductor device comprising: a control circuit mounted on the support block; and a lead of the IC connected to the power circuit and the control circuit. 5. The semiconductor device according to claim 4, wherein the power element driving IC is of a dual-in-line package type, wherein one of the leads is placed above and the other is placed with the package of the IC standing upright. A semiconductor device, wherein the semiconductor device is drawn out, inserted into a support block in this position, and integrally molded with an outer case. 6. The semiconductor device according to claim 1, wherein an auxiliary substrate extending laterally from said substrate and having leads formed on the upper surface of said substrate is integrally formed on a power circuit substrate of said power circuit. A semiconductor device, comprising: mounting a circuit board on a metal base plate; bending the auxiliary board to stand up; and connecting its lead to a control circuit disposed above. 7. A semiconductor device according to claim 6, wherein the auxiliary substrate that has been erected is held in a fitting manner along with a support block integrally formed on the bottom side of the outer case.