JPH05299546A - Semiconductor device - Google Patents

Abstract

(57) [Summary] [Structure] A heat radiation fin 2 is screwed to one surface of a heat diffusion plate 4 to which a semiconductor chip 8 is fixed so that the heat radiation fin 2 can be attached and detached. In a semiconductor device having a structure in which heat is dissipated by the heat radiation fins 2 via the diffusion plate 4, the heat radiation fins 2 and the heat diffusion plate 4 are
A semiconductor device characterized in that the heat radiation fin and the heat diffusion plate are bonded to each other with a silicone rubber adhesive 3 interposed therebetween. [Effect] When a silicone rubber adhesive is interposed between the heat radiation fins and the heat diffusion plate to join the heat radiation fins and the heat diffusion plate, the contact efficiency between them is improved due to the interposition of the elastic material. , When the heat dissipating fin is tightened and fixed to the heat diffusion plate with the nut, the elastic body made of the silicone rubber adhesive can absorb warp of the member.
The contact thermal resistance can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly, to a heat dissipating plate to which a semiconductor chip is fixed. The present invention relates to a technique capable of further improving heat dissipation in a semiconductor device having a structure in which heat is dissipated by a heat dissipation fin via the heat diffusion plate.

[0002]

2. Description of the Related Art A semiconductor chip (hereinafter, simply referred to as a chip) is fixed to a heat diffusion plate, a heat radiation fin is fixed to a top surface of the heat diffusion plate with a screw (bolt), and a ceramic bottom surface of the heat diffusion plate. There is a semiconductor device having a structure in which a wiring board is joined, the chip and the wiring board are electrically connected, and heat generated from the chip is radiated through the heat diffusion plate and the heat dissipation fin in order. In this case, copper (Cu) -tungsten alloy is used as the material of the heat diffusion plate in consideration of the thermal expansion coefficient of the ceramic wiring board, and
Silver brazing using silver brazing is used for screwing the heat radiation fins. On the other hand, in a plastic ping-lit array type package using a resin wiring board, the heat diffusion plate and the heat dissipation fin are bonded by a silicone rubber adhesive.

[0003]

However, in the structure for attaching and detaching the heat radiation fins, when the heat radiation fins are fixed to the heat diffusion plate with screws (bolts), when they are tightened and fixed with nuts,
Since warpage is generated on the side of these members, the contact thermal resistance between the heat diffusion plate and the heat dissipation fin has been a serious problem. Further, in the above-mentioned conventional technique, in order to reduce the thermal resistance,
Although a heat conductive sheet is interposed between the heat diffusion plate and the heat dissipation fin, the sheet has a large variation in contact thermal resistance and cannot absorb the warp, and the cost of the sheet itself is high. There was a problem. The present invention is
It is an object of the present invention to solve the drawbacks of the conventional technique and to provide a technique capable of further improving the heat dissipation in the semiconductor device having the above structure, particularly in the plastic pingrit array type package. The above and other objects and novel features of the present invention will be apparent from the description of the present specification and the accompanying drawings.

[0004]

The outline of a typical one of the inventions disclosed in the present application will be briefly described as follows. In the present invention, the heat dissipation fin and the heat diffusion plate are joined by interposing a silicone rubber adhesive between the heat dissipation fin and the heat diffusion plate.

[0005]

As described above, in the heat radiation fin attachment / detachment structure, the contact thermal resistance between the heat diffusion plate and the heat radiation fin becomes a serious problem. As in the present invention, when the heat dissipation fin and the heat diffusion plate are joined by interposing a silicone rubber adhesive between the heat dissipation fin and the heat diffusion plate, the contact efficiency of the heat dissipation fin and the heat diffusion plate is increased due to the interposition of the elastic material. When the heat dissipating fins are tightened and fixed to the heat diffusion plate with a nut, the elastic body made of the silicone rubber adhesive can absorb warp of the member, thereby reducing the contact heat resistance. be able to. In this case, a silicone rubber adhesive may be applied to either the heat diffusion plate or the radiating fins, but if a high heat conductive silicone rubber adhesive is applied to both of them, they will come into contact with each other. Elastic materials are located on both sides of the member, and both can absorb warpage, so the thermal resistance can be further reduced, and since the contact area and contact pressure surely increase compared to only one side, the thermal resistance is further reduced. it can. Further, by devising the shape of the adhesive, for example, by making it triangular, the contact of the tip portions can be achieved, and the thermal resistance can be further reduced as compared with the contact between flat surfaces. Further, in the above structure, heat is directly conducted and radiated to the tapped portion, so if the silicone rubber adhesive is concentratedly applied to that portion, the thermal resistance can be further reduced, which is advantageous. Is.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. Example 1 . One embodiment will be described with reference to FIGS.
The present embodiment shows a case of being applied to a plastic pin grid array type package, which includes a screw 1, a heat radiation fin 2, a silicone rubber adhesive 3, a heat diffusion plate 4, a bonding material 5, a package (wiring board). ) 6, die bonding agent 7, chip 8, connector wire 9, cap 10, lead pin 11, and nut 12. As shown in FIG. 1, a silicone rubber adhesive 3 is applied to the entire bottom surface of the heat dissipation fin 2. That is, the silicone rubber adhesive 3 is applied to the entire area where the lower surface of the heat radiation fin 2 and the upper surface of the heat diffusion plate 4 are in contact with each other. As shown in the figure, the chip 8 is fixed to the lower convex surface of the inversely convex heat diffusion plate 4 by the die bonding agent 7. The heat generated from the chip 8 is radiated from the heat dissipation fin 2 via the heat diffusion plate 4. The other surface of the inversely convex heat diffusion plate 2 excluding the convex portion is fixed to the upper surface of the wiring board 6 by the bonding material 5. Although not shown, external wiring is laid on the step portion of the wiring board 6, and electrodes (not shown) of the chip 8 and the external wiring of the step portion are electrically connected by the connector wire 9. It is connected. The external wiring is electrically connected to an external lead pin 11 which is provided so as to extend downward from the wiring board 6 to input / output a signal to / from the chip 8 and cause the chip 8 to function. As shown in FIGS. 1 and 2, the lower surface of the heat dissipation fin 2 and the upper surface of the heat spreader 4 which are hardened and coated with a silicone rubber adhesive 3 are joined together to form the heat dissipation fin 2.
Pass the screw 1 through the hole formed in the hole and tighten with the nut 12. The heat dissipation fin 2 is made of a metal such as aluminum. The heat diffusion plate 4 is made of a metal plate such as aluminum. The wiring board 6 is
For example, it is composed of a resin wiring board or a ceramic wiring board. The chip 8 is made of, for example, a silicon single crystal substrate, has a large number of circuit elements formed therein by a well-known technique, and is given one circuit function. A specific example of the circuit element is, for example, a MOS transistor,
The circuit functions of the logic circuit and the memory are formed by these circuit elements, for example. The cap 10 is made of a metal plate such as aluminum. The connector wire 9 is made of, for example, an Au thin wire. The lead pin 11 is made of, for example, a Ni—Fe alloy. The bonding material 5 is preferably made of a silicone rubber-based bonding material similar to the silicone rubber-based adhesive 3. The silicone rubber adhesive 3 (5)
As the main component, a silicone rubber having a rubber-like property having a Si-O molecular skeleton can be used, and a heat vulcanization type that vulcanizes by heating or a mixture of curing agents is used when moisture in air is used. Room temperature vulcanization type (RTV silicone)
Can be used. As the silicone rubber-based adhesive, one having high thermal conductivity may be used. According to the present embodiment, as a structure for attaching / detaching the heat dissipation fins 2, a highly heat-conductive silicone rubber adhesive 3 is applied to the entire surface where the heat dissipation fins 2 and the heat diffusion plate 4 are in contact with each other and vulcanized. As a result, an elastic body is formed from a silicone rubber adhesive, and the elasticity improves contact efficiency. When the heat radiation fin 2 and the heat diffusion plate 4 are tightened and fixed by the bolt 1 and the nut 12, these members 2 Even if warp occurs on the 4th side, it can be absorbed, so the contact thermal resistance can be reduced. Further, since the silicone rubber itself constituting the silicone rubber adhesive 3 has good thermal conductivity, the thermal resistance can be reduced throughout the package.

Example 2 The embodiment shown in FIG. 3 is a plastic pin grid array type similar to the embodiment 1 except that the silicone rubber adhesive 3 is applied to both the lower surface of the heat dissipation fin 2 and the upper surface of the heat diffusion plate 4. An example of configuring a package is shown. According to the present embodiment, since the silicone rubber adhesive 3 having high thermal conductivity is applied to both the heat diffusion plate 4 and the heat dissipation fin 2, the high thermal conductivity is applied to both sides of the members 2 and 4 which are in contact with each other. Since the elastic substance composed of the silicone rubber adhesive 3 is located, and the elastic substance composed of the silicone rubber adhesive 3 can absorb the sled, the thermal resistance can be further reduced, and more than one side, Since the contact area and the contact pressure are surely increased, the thermal resistance can be further reduced.

Example 3 The embodiment shown in FIG. 4 is the same as the embodiment 1 except that the shape of the silicone rubber adhesive 3 applied to the lower surface of the heat dissipation fin 2 is devised and the shape of the adhesive is triangular as shown in the figure. An example of constructing a plastic pin grid array type package is shown below. As a result, the contact between the adhesive 3 on the lower surface of the heat dissipation fin 2 and the upper surface of the heat diffusion plate 4 becomes a contact at the tip portion, and the thermal resistance is further reduced as compared with the contact between the flat surfaces shown in the above embodiment. it can.

Example 4 The example shown in FIG. 5 is an example in which a plastic pin grid array type package is configured in the same manner as in Example 1 except that the high thermal conductive silicone rubber adhesive 3 is applied only to the vicinity of the tap. Show. Since heat is directly conducted and radiated to the tapped portion, heat resistance can be further reduced by applying the silicone rubber adhesive 3 intensively to the tapped portion as shown in the figure. Therefore, it is advantageous. The invention made by the present inventor has been specifically described based on the embodiments.
It is needless to say that the present invention is not limited to the above-mentioned embodiments and can be variously modified without departing from the gist thereof. In the above description, the case where the invention made by the present inventor is mainly applied to a pingrit array type package which is a field of application which is the background of the invention has been described, but the invention is not limited thereto and other semiconductor devices can be used. Applicable.

[0010]

The effects obtained by the representative ones of the inventions disclosed in this application will be briefly described as follows. According to the present invention, it is possible to provide a technique capable of further improving the heat dissipation in the semiconductor device having the above structure, particularly in the plastic ping-lit array type package.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an entire semiconductor device showing an embodiment of the present invention, which is a cross-sectional view of a heat dissipation fin before screwing;

FIG. 2 is a cross-sectional view of the entire semiconductor device showing one embodiment of the present invention, which is a cross-sectional view after screwing the heat radiation fins;

FIG. 3 is a sectional view showing another embodiment of the present invention.

FIG. 4 is a sectional view showing still another embodiment of the present invention.

FIG. 5 is a sectional view showing still another embodiment of the present invention.

[Explanation of sign]

 DESCRIPTION OF SYMBOLS 1 ... Screw, 2 ... Heat dissipation fin, 3 ... Silicone rubber adhesive, 4 ... Thermal diffusion plate, 5 ... Bonding material, 6 ... Wiring board (package), 7 ... Die bonding agent, 8 ... Chip, 9 ... Connector wire, 10 ... Cap, 11 ... Lead pin, 12 ... Nut

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshihiro Tsuboi 5-20-1, Josuihonmachi, Kodaira-shi, Tokyo Inside Hiritsu Cho-LS Engineering Co., Ltd. (72) Inventor Hiroshi Ozaki Kodaira, Tokyo 5-20-1 Joumizu Honmachi, Ichi, Japan, within Hitate Cho-LS Engineering Co., Ltd. (72) Inventor, Yoshiyuki Shirai 2326 Imai, Ome-shi, Tokyo Hitachi, Ltd. Device Development Center (72) Invention Takashi Miwa 2326 Imai, Imai, Ome-shi, Tokyo, Hitachi, Ltd. Device Development Center (72) Toshihiro Matsunaga 2326, Imai, Ome, Tokyo, Tokyo, Hitachi, Ltd. Device Development Center

Claims (2)

[Claims] 1. A heat dissipating fin is screwed to one surface of a heat diffusion plate plate to which a semiconductor chip is fixed so that the heat dissipating fin can be attached and detached. In a semiconductor device having a structure for radiating heat, the heat radiation fin and the heat diffusion plate are joined by interposing a silicone rubber adhesive between the heat radiation fin and the heat diffusion plate. Semiconductor device. 2. The heat radiation fin and the heat diffusion plate are joined together by partially applying a silicone rubber adhesive around the tapped portion between the heat radiation fin and the heat diffusion plate. Characteristic semiconductor device.