JP2002198477A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reliable semiconductor device in which such small and low-cost semiconductor chip as a IGBT can be used for good workability in assembling and the like and for assured heat dissipating characteristics, by solving problems related to a semiconductor device of a conventional heat dissipating structure, especially the one in which a semiconductor chip comprises an insulating gate type bipolar transistor(IGBT), where the semiconductor chip rises because it is directly fitted to a fixed member with a screw and the like, otherwise the resin of semiconductor chips cracks when the screw or the like is excessively tightened. SOLUTION: A fixing member 1 such as a screw fixes an elastic member 11 which contacts a semiconductor chip 2 by a surface opposite to the surface of the semiconductor chip 2 which faces a heat dissipating member 4, to provide a compressing force, so that the semiconductor chip 2 is pressurized toward the heat dissipating member 4 by an even surface pressure. An insulating sheet 3 is provided away from the fixing member 1 such as a screw, with no hole opened through which a fixing member such as a screw which can cause a short circuit is inserted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device having a heat dissipation structure, and more particularly to a semiconductor device in which a semiconductor chip is an insulated gate bipolar transistor (IGBT).

[0002]

2. Description of the Related Art Conventionally, a power switching device such as an IGBT has a structure in which a device is directly screwed to a heat radiating member in order to release heat generated by its high-speed and large-power operation. FIG. 4 shows a typical conventional example of a semiconductor device having a heat dissipation structure. In FIG. 4, a fixing member 1 is a member for fixing a semiconductor chip 2 to a heat radiating member 4 via an insulating sheet 3, and is typically a screw or the like. A hole 5 is formed in the semiconductor chip 2 and a hole 6 is formed in the insulating sheet 3 for passing the fixing member 1 such as a screw. Note that a semiconductor chip is generally used when referring to an individual semiconductor chip such as a transistor or a monolithic semiconductor integrated circuit chip. Here, however, a wide variety of multichip integrated circuits including two or more monolithic semiconductor LSIs and devices other than semiconductor chips are used. Including hybrid integrated circuits, etc., broadly refers to those in which a semiconductor element is included in a single chip, and in the present invention, in particular, a mold IGBT will be described in detail including a comparison with a conventional example. It is not limited to. Referring to the case where the semiconductor chip 2 is, for example, a molded IGBT in FIG. 4, the emitter terminal 7, the collector terminal 8,
It has a gate terminal 9. In addition to the external terminals connected to these circuit boards, the emitter electrode 10 of the IGBT is exposed on the back of the mold.

The operation of this structure will be described. In the molded IGBT, the emitter terminal 7 is set to 0 V (GND), the collector terminal 8 is set to, for example, +216 V, and the gate terminal 9 is set.
To control high-speed power switching operation,
The operating heat is transmitted to the exposed emitter electrode 10 on the back of the mold. Here, the fixing member 1 is a mold IG
Since the BT is directly and firmly fixed to the heat radiating member 4 via the insulating sheet 3, the exposed back surface of the molded IGBT is closely attached to the heat radiating member 4 made of, for example, a metal material having good heat conductivity through the insulating sheet 3. Heat is dissipated.
The insulating sheet 3 electrically insulates the exposed emitter electrode 10 from the heat dissipation member 4 made of, for example, a metal material.

Japanese Patent Laid-Open Publication No. Hei 8-236667 discloses a semiconductor device having an insulating plate on which a semiconductor chip is mounted, a resin case surrounding the semiconductor chip, and a heat sink attached with the insulating plate. As means for attaching to the radiator plate, a semiconductor device having a structure in which the insulating plate is pressed against the radiator plate using the resin case has been proposed.In an embodiment of the present invention, the resin case is connected via a spring. Bolts against the heat sink. Further, in JP-A-2000-299419,
In a semiconductor device in which a substrate on which a semiconductor chip is mounted is pressed against both ends of the substrate by applying a pressing force to a heat radiating member,
The present invention proposes a semiconductor device characterized in that the substrate is formed so as to be curved toward the pressure contact side of the heat radiating member, and in the embodiment of the invention, both ends of the substrate are pressed by leaf springs. The leaf spring is fastened to the heat radiating member with a screw.

[0005]

In the prior art shown in FIG. 4 of the above-mentioned semiconductor devices, for example, a mold IG
Since the semiconductor chip such as BT is directly attached with a fixing member such as a screw, there is a problem that the semiconductor chip floats due to loosening of the screw or the like, or a crack occurs in the resin of the semiconductor chip due to excessive tightening of the screw or the like.

For example, electrical insulation between the exposed emitter electrode on the back surface of the IGBT and a heat radiating member made of a material such as metal is performed by an insulating sheet. Since the hole 6) of No. 4 is formed, the position of the insulating sheet is shifted, so that the entire emitter electrode cannot be covered with the insulating sheet, and there is a risk that an electrical short circuit may occur between the heat radiation member and the emitter electrode.

Further, since the fixing portion of the fixing member such as a screw is disposed apart from the emitter electrode for transmitting heat, the semiconductor chip such as an IGBT by tightening the screw uniformly applies a surface pressure to the heat radiating member. No heat radiation was observed. Due to this decrease in heat radiation, the expected characteristics of the semiconductor chip cannot be sufficiently exhibited, and as a result, a semiconductor chip having a larger power capacity is used, resulting in an increase in size and cost of the semiconductor device.

In the example of the semiconductor device proposed in the patent publication, the insulating plate or the substrate on which the semiconductor chip is mounted is not directly attached to the heat radiating member by a fixing member such as a bolt or a screw. The case has a structure in which both ends of the insulating plate or the substrate on which the semiconductor chip is mounted are pressed or pressed against the heat dissipating member via a spring. Or, since it is an end portion, surface pressure is not evenly applied to the entire insulating plate or substrate on which the semiconductor chip is mounted, and there is a problem that heat dissipation is reduced. In addition, since it has a complicated structure, it is difficult to assemble and cannot be reduced in size, resulting in a high price.

An object of the present invention is to solve the problems of a conventional semiconductor device having a heat dissipation structure, particularly a semiconductor chip having an insulated gate bipolar transistor (IGBT), and to provide a small and inexpensive semiconductor chip such as an IGBT. An object of the present invention is to provide a semiconductor device which can be used, has excellent workability in assembling and the like, secures heat dissipation, and has high reliability.

[0010]

According to a first aspect of the present invention, there is provided a semiconductor device having an integrated circuit chip and a heat radiating member, wherein the semiconductor chip has a heat radiating member. On the surface opposite to the surface facing the fin, the elastic member is pressed against the heat radiating member by the compressive force of the elastic member.

A semiconductor device according to a second aspect of the present invention is the semiconductor device according to the first aspect, wherein the elastic member is a leaf spring, and is located on a side opposite to the heat radiation member with the semiconductor chip interposed therebetween. Is characterized by being covered.

In a semiconductor device according to a third aspect of the present invention, in the second aspect, the leaf spring is a part of a plate formed by processing a resilient plate, and the plate has at least one plate. It has a leaf spring portion and a portion extending along the leaf spring portion, and the extended portion is provided with at least one positioning member for a terminal of the semiconductor chip.

In the first aspect of the invention, the semiconductor chip is not directly attached to the heat radiating member by a fixing member such as a screw, but the surface of the semiconductor chip opposite to the surface facing the heat radiating member is elastically fixed by using an elastic member. Since the semiconductor chip is pressed against the heat radiating member by the compressive force of the member, the semiconductor chip does not float or crack, and the surface pressure is evenly applied, so that sufficient heat radiation can be obtained. Further, the insulating sheet has no hole through which a fixing member such as a screw which causes an electric short circuit passes.

In the second aspect of the present invention, since the elastic member is formed of a leaf spring and covers the upper part of the semiconductor chip, it can be manufactured inexpensively and easily, and can have a shielding effect.

In a third aspect of the present invention, the leaf spring constituting the elastic member is a part of a plate formed by processing a resilient plate. Since the extending portion has the positioning member for the terminal of the semiconductor chip, the semiconductor chip can be easily assembled. When one plate has at least one, that is, a plurality of leaf springs and a positioning member, a plurality of semiconductor chips can be easily integrated with a reduced volume of the entire semiconductor device.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a first embodiment according to the first and second inventions. Here, the same reference numerals are given to the same components as those in FIG. The fixing member 1 such as a screw fixes the elastic member 11, and the elastic member 11 contacts the semiconductor chip 2 on the surface of the semiconductor chip 2 opposite to the surface facing the heat radiating member 4 to generate a compressive force, The elastic member 11 is pressed against the heat radiating member 4 from above the heat generating portion (emitter electrode 10). The insulating sheet 3 is arranged at a position separated from the fixing member 1 such as a screw. The elastic member 11 has a structure shown in FIG.
As shown in (a), the upper surface of the semiconductor chip 2 is covered.

In the first embodiment, the semiconductor chip 2 includes the elastic member 1 supported by the fixing member 1.
Due to the compressive force of 1, the elastic member 1 is moved from above the heating portion (emitter electrode 10) of the semiconductor chip 2 via the insulating sheet 3.
At 1, the pressure is pressed against the heat radiating member 4, the surface pressure is uniformly applied, and a decrease in heat radiation due to uneven surface pressure is prevented. The elastic member 11 can be made as a leaf spring or the like from a springy plate material such as high-carbon steel, stainless steel, a copper alloy or the like.
In this case, since the surface pressure is uniformly applied to the semiconductor chip, for example, the mold of +216 V and 300 A class described in the embodiment is used.
In the case of one IGBT, the pressing force is about 10 kg and the heat radiation characteristics can be sufficiently secured. The heat dissipating member 4 can be made of a metal plate, preferably a metal plate such as copper or aluminum. Further, since the insulating sheet 3 can be made of a silicon resin sheet or the like and has no holes for passing the fixing members 1 such as screws, the insulation between the emitter electrode 10 and the heat radiating member 4 made of a metal material or the like is completely electrically insulated. Is done. The elastic member 11 is a semiconductor chip 2
It has a shielding effect because it covers the upper surface of the.

FIG. 2 shows a second embodiment according to the second and third inventions. Here, the same components as those in FIGS. 4 and 1 are denoted by the same reference numerals. Here, a fixing member 1 such as a screw
Fixes the elastic member 11, and the elastic member 11 comes into contact with the semiconductor chip 2 on the surface opposite to the surface facing the heat radiating member 4 of the semiconductor chip 2, generates a compressive force, and generates a heat generating portion (emitter) of the semiconductor chip 2. The electrode 10) is pressed against the heat radiating member 4 by the elastic member 11 from above to prevent a decrease in heat radiating property due to uneven surface pressure. The insulating sheet 3 is disposed at a position separated from the fixing member 1 such as a screw. This is the same configuration and operation as in FIG. Here, the elastic member 11 is a plate 14
Formed as part of That is, the plate 14 corresponds to FIG.
As can be understood from the comparison, in addition to the portion 11 constituting the elastic member, the elastic member has a portion 12 extending along the portion 11 constituting the elastic member. Terminal 7 of the semiconductor chip
Eight and nine positioning members 13 are provided. The positioning member 13 has three tapered holes having a large hole diameter on the semiconductor chip side, and the terminals 7,
8 and 9 are inserted, and the substrate 1 of the target device (not shown)
5 is connected.

In the second embodiment, the semiconductor chip 2 is separated from the semiconductor chip 2 by the compressive force of the portion 11 forming an elastic member as a part of the plate 14 supported by the fixing member 1 via the insulating sheet 3. The elastic member 11 is pressed against the heat dissipating member 4 from the upper part of the heat generating portion (emitter electrode 10) 2 to apply a uniform surface pressure to the semiconductor chip. The operation is the same as in the first embodiment. Further, since the upper surface of the semiconductor chip 2 is covered by the portion 11 forming the elastic member of the plate 14 and the portion 12 extending along the portion 11 forming the elastic member, the shielding effect is reduced in the first embodiment.
Even better. Further, the terminals 7, 7 of the semiconductor chip are located at positions of the extending portions 12 beyond the semiconductor chip 2.
Since the semiconductor chip side has three tapered holes having a large hole diameter, the positioning members 13 are provided with the terminals 7, 8, 9 of the semiconductor chip 2 in these three holes. Can be inserted smoothly, and the assemblability is greatly improved. The positioning member 13 having such a shape can be easily manufactured integrally with a plate made of a resilient material such as a metal material by an outsert molding method or the like, for example, using resin as a material. Further, the portion 1 constituting the elastic member on the plate 14 as described above.
Since the positioning member 1 and the positioning member can be manufactured integrally, the number of parts is greatly reduced.

FIG. 3 shows a third embodiment according to the third invention. 3, the same components as those in FIGS. 1, 2, and 4 are denoted by the same reference numerals. In the third embodiment, a plurality of parts of the second embodiment are integrally manufactured, and the configuration and operation of basic units are the same as those of the second embodiment.
FIG. 3 shows an example in which six units of the second embodiment are integrally manufactured, but the number is not limited to six. Here, the fixing member 1 is arranged, for example, in FIG. 3 by arranging three semiconductor chips 2 in two rows and in the middle of the row. This greatly reduces the number of fixing members 1 as compared with the case where the second embodiment is individually adopted. Also, due to the operation of the positioning member 13, even if the number of semiconductor chips increases, the semiconductor chip can be easily assembled.

[0021]

As described above, in the first aspect, the semiconductor chip is not directly attached to the heat radiating member by the fixing member such as the screw, but the semiconductor chip is provided on the surface opposite to the surface facing the heat radiating member. Since the semiconductor chip is pressed against the heat radiating member by the compressive force of the elastic member, the semiconductor chip does not float or crack, and the surface pressure is evenly applied. As a result, a semiconductor chip having a smaller power capacity can be used, and the size and price of the semiconductor device can be reduced.

Further, since the insulating sheet has no hole for passing a fixing member such as a screw which causes an electric short circuit, an electric short circuit does not occur between the heat radiation member and the emitter electrode.

In the second invention, since the elastic member is constituted by a leaf spring and covers the upper part of the semiconductor chip, it can be manufactured easily at low cost and has a shielding effect.

In a third aspect of the present invention, the plate spring is a part of a plate formed by processing a resilient plate, and a portion extending along the plate spring portion is provided with the semiconductor chip. Since it has a terminal positioning member,
Semiconductor chips can be easily incorporated. When one plate has at least one plate spring, that is, a plurality of leaf springs and positioning members, the number of components in a semiconductor device having a plurality of semiconductor chips is greatly reduced, and the semiconductor device can be easily incorporated. As a result, the cost and size can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view and a plan view of a first embodiment of the present invention.

FIG. 2 is a front view and a plan view of a second embodiment of the present invention.

FIG. 3 is a plan view and a front view of a third embodiment of the present invention.

FIG. 4 is a front view and a plan view of a conventional example.

[Explanation of symbols]

1 fixing member, 2 semiconductor chip, 3 insulating sheet, 4
Heat dissipation member, 5 holes, 6 holes, 7 emitter terminals, 8
Collector terminal, 9 gate terminal, 10 emitter electrode,
11 elastic member, 12 a portion extending along the elastic member,
13 positioning member, 14 plate, 15 substrate.

Claims (3)

[Claims] 1. A semiconductor device having a semiconductor chip and a heat radiating member, wherein the semiconductor chip is pressed against the heat radiating member by a compressive force of an elastic member on a surface opposite to a surface facing the heat radiating member. A semiconductor device characterized in that: 2. The semiconductor device according to claim 1, wherein the elastic member is a leaf spring, and is located on a side opposite to the heat radiating member across the semiconductor chip and covers an upper part of the semiconductor chip. . 3. The plate spring according to claim 2, wherein the plate spring is a part of a plate formed by processing a spring plate.
The plate has at least one leaf spring portion and a portion extending along the leaf spring portion, and the extending portion has at least one positioning member for a terminal of the semiconductor chip. A semiconductor device characterized by the above-mentioned.