JP2002270738A - Heat sink for semiconductor device and semiconductor device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heat dissipating effect by preventing formation of a gap between a heat sink and a semiconductor device main body. SOLUTION: A heat sink for a semiconductor device is constituted by combination of a first heat sink 10 and a second heat sink 20. A first heat sink 10 side on which the semiconductor device main body 2 is mounted is formed of material of copper or the like whose thermal conductivity is higher than that of aluminum, aluminum alloy, etc., and heat generation from the semiconductor device main body 2 is conducted quickly to the second heat sink 20. As a result, warp is not generated in the semiconductor device main body 2, especially, in its heat dissipating plate, and a gap is not formed to the first heat sink 10, so that heat dissipating effect can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat sink for a semiconductor device used for heat dissipation of a semiconductor device.
And a semiconductor device using the same.

[0002]

2. Description of the Related Art As is well known, a semiconductor device having a high output and a large amount of heat is provided with a plurality of radiating fins (radiating fins).
Are provided so as to be in contact with each other, and the heat sink radiates heat from the semiconductor device.
Such a heat sink is generally made of a material having a high thermal conductivity such as aluminum or an aluminum alloy because the cooling efficiency is higher as the thermal conductivity is higher, and is formed by extrusion.

FIGS. 7A to 7C show an example of a semiconductor device using this type of heat sink. In the figure, 1
7 shows the entire semiconductor device, and the semiconductor device 1 is shown in FIG.
As shown in FIGS. 1A and 1B, a semiconductor device main body 2 and a heat sink 3 made of, for example, aluminum are provided. Although not shown, a semiconductor chip is mounted and fixed on a heat sink via an insulating plate inside the semiconductor device body 2, and a predetermined external lead-out terminal is led out from the upper surface of the insulating case. Also,
The outer surface of the heat sink on which the semiconductor chip is mounted is exposed on the lower surface side of the insulating case, and is fixed by screws 4 so that the exposed outer surface is in contact with the upper surface of the heat sink 3. FIG. 7C shows an example in which the semiconductor device main body 2 having no insulating case is directly mounted on the heat sink 3 by soldering or the like.

The heat sink 3 is formed by arranging a plurality of plate-shaped radiating fins 3a at predetermined intervals so as to have a sectional shape of a blade plate or a sectional shape provided with a plurality of slits 3b. It had been. These heat sinks 3 have a function of efficiently radiating the heat generated in the semiconductor device body 2 to the outside, and are designed so that the heat generation efficiency is optimized according to the electrical characteristics and the external shape of the semiconductor device. ing.

The conventional semiconductor device 1 is configured as described above. In particular, when the heat sink 3 is not optimally designed, as shown in FIG. Due to the expansion, a gap is generated between the heat sink 5 and the heat sink 3, and the heat generated from the semiconductor chip 6 can be efficiently conducted to the heat sink 3 and the heat cannot be dissipated. there were.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has been made to eliminate heat generated from a semiconductor chip without forming a gap between the heat sink and the semiconductor device body. It is an object of the present invention to provide a heat sink for a semiconductor device capable of efficiently dissipating heat through a semiconductor device and a semiconductor device using the same.

[0007]

The heat sinks for semiconductor devices of the present invention are made of different materials, for example, the first heat sink is made of copper (Cu) and the second heat sink is made of aluminum (Au). And the semiconductor device main body is mounted on the first heat sink side. The heat conductivity (20 ° C.) of Cu in the first heat sink is 3.72 (W / cm ° C.), and the heat conductivity of Al in the second heat sink is 2.04 (W / cm ° C.). And the first heat sink has a relatively higher thermal conductivity than the second heat sink. Further, the contact surface of the semiconductor device body mounted on the first heat sink is a heat radiating plate made of copper, and the heat radiating plate and the first heat sink are in contact with each other, but the heat conductivity of both are equal. The heat generated at the semiconductor junction inside the semiconductor device body due to this is transmitted to the first heat sink via the heat sink, and further from the first heat sink to the second heat sink. After being transmitted, it is released into the air. As a result, warpage due to thermal expansion of the radiator plate is prevented, and no gap is formed between the radiator plate and the first heat sink, so that the radiating effect can be improved. Further, the semiconductor device of the present invention becomes a semiconductor device having high performance and stable characteristics by using the heat sink having the above configuration.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
This will be described with reference to the drawings. FIG. 1 shows a first embodiment of the present invention. In the figure, the semiconductor device heat
The sink comprises a combination of a first heat sink 10 and a second heat sink 20 formed of different materials. And the first heat sink 10
Is formed of a material having a relatively higher thermal conductivity than the heat sink 20 of FIG.

That is, the first heat sink 10
For example, it is formed of a Cu material. Further, the first heat sink 10 has a mounting surface 11 on which the semiconductor device body 2 is mounted, and a surface 12 facing the second heat sink 20 on the back side of the mounting surface 11. ing. further,
A pair of second heat sinks 20 provided with an extending portion 13 protruding outwardly (downward in the figure) from a substantially central portion of the facing surface 12 and having a plurality of heat radiation fins 21 in the horizontal direction.
Are arranged in close contact with the extending portion 13.

[0010] The first heat sink 10 comprises:
Although it is formed of a Cu material, it can be easily manufactured by cold forging because it has a shape in which the central portion simply protrudes downward. Also, the second heat
The sink 20 is formed of a material such as aluminum, an aluminum alloy, iron, or the like as in the related art. However, in some cases, the second heat sink 20 may be formed of a copper material. The point is that the mounting surface that is in direct contact with the semiconductor device body 2 may be made of a material having a high thermal conductivity such as a copper material. Further, the first and second heat sinks 10 and 20 may be subjected to a surface treatment such as mica to further improve the thermal conductivity. Further, the direction of the plurality of radiating fins 21 is not necessarily limited to the horizontal direction, and may be, for example, diagonally upward, diagonally downward, vertically downward, or the like. Further, when a semiconductor device is manufactured using the heat sink having the above-described configuration, the heat radiation effect is significantly improved, and a semiconductor device having high performance and stable characteristics can be obtained.

FIG. 2 shows a modification of the first embodiment. In this modification, the opposing surface 1 of the first heat sink 10
A space 24 having a predetermined interval is formed between the second outer surface 23 and the upper outer surface 23 of the second heat sink.

The heat sink having the above-described configuration is used when the semiconductor device body 2 such as a power module is disposed on the mounting surface 11 of the first heat sink 10 and used. Sink 10 has a relatively higher thermal conductivity than second heat sink 20. And the first
The contact surface of the semiconductor device main body 2 mounted on the heat sink 10 is a copper radiator plate, and this radiator plate and the first heat sink 10 come into contact with each other, but since the two have the same thermal conductivity, the semiconductor device has Heat generated at the semiconductor junction inside the main body 2 is transmitted to the first heat sink 10 via the heat sink, and further transmitted from the first heat sink 10 to the second heat sink 20. After being released into the air. As a result, warpage due to thermal expansion of the radiator plate is prevented, and no gap is formed between the first heat sink 10 and the semiconductor device main body 2, so that the heat radiation effect can be improved.
In actual use, the semiconductor device body 2 and the first
A suitable thermal compound, joint compound or the like may be applied between the heat sink 10 and the heat sink 10.

In a modification of the first embodiment, the opposing surface 12 of the first heat sink 10 and the second heat sink
Since the space portions 24 are formed at predetermined intervals without making close contact with the upper outer surface 23 of the sink 20, the space portions 24 are designed by optimally designing the intervals of the space portions 24.
Can be expected to dissipate heat into the air due to natural convection.

FIG. 3 shows a second embodiment of the present invention. In this embodiment, a pair of second heat sinks 20 arranged in close contact with the extending portions 13 of the first heat sink 10 are formed in a box shape having a cavity 22. The hollow portion 22 may be a single one as shown, but may be a plurality of slits.

FIG. 4 shows a third embodiment of the present invention. In this embodiment, the first heat sink 10
A mounting surface 11 on which the semiconductor device body 2 is mounted;
And an extension 13A protruding outward at a substantially right angle from one end of the facing surface 12 and having an opposite surface 12 facing the second heat sink 20 on the back surface side of the first heat sink 20. The second heat sink 20 having a plurality of radiating fins 21 in the horizontal direction is arranged in close contact with the inner side surface of 13A.

In the third embodiment, as in the first embodiment, the heat generated at the semiconductor junction inside the semiconductor device body 2 is supplied to the first heat sink 10 via the heat sink. To the first heat sink 1
After being transmitted from 0 to the second heat sink 20, it is dissipated into the air. As a result, warpage due to thermal expansion of the radiator plate is prevented, and no gap is formed between the first heat sink 10 and the semiconductor device main body 2, so that the heat radiation effect can be improved.

FIG. 5 shows a modification of the third embodiment. In this modification, the opposing surface 1 of the first heat sink 10
A space 24 having a predetermined space is formed between the second heat sink 2 and the upper outer surface 23 of the second heat sink.

FIG. 6 shows a fourth embodiment of the present invention. In this embodiment, the first heat sink 10
The second heat sink 20, which is disposed in close contact with the inner surface of the extending portion 13A, is formed in a box shape having a cavity or a plurality of slits (a single cavity 22A in the figure). . According to this embodiment as well, no gap is formed between the first heat sink 10 and the semiconductor device body 2 as described above, and the heat radiation effect can be improved.

[0019]

As described above, according to the present invention, a heat sink for a semiconductor device is constituted as a combination of a first heat sink and a second heat sink, and a first heat sink for mounting a semiconductor device main body. Aluminum on the heat sink side
It is made of a material such as copper having higher thermal conductivity than aluminum alloy and the like, and heat generated from the semiconductor device main body is quickly transferred to the second heat sink. No warpage occurs, and no gap is formed between the first heat sink and the first heat sink, so that the heat radiation effect can be improved. Also, as in the past, the heat sink itself was increased in size to enhance the heat radiation effect, or the heat sink was made complex in order to increase the surface area of the fin,
There is no need to increase the plate thickness, and the cost is reduced. Further, when the entire heat sink is made of a copper material, it is difficult to shape the heat radiating fins and the like. However, in the present invention, the first heat sink made of copper has a simple shape, and thus is formed by cold forging or the like. Can be manufactured. Further, when a semiconductor device is manufactured using the heat sink having the above-described configuration, there is an excellent effect that a heat radiation effect is remarkably improved, and a semiconductor device having high performance and stable characteristics is obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is a perspective view showing a modification of the first embodiment.

FIG. 3 is a perspective view showing a second embodiment of the present invention.

FIG. 4 is a perspective view showing a third embodiment of the present invention.

FIG. 5 is a perspective view showing a modification of the third embodiment.

FIG. 6 is a perspective view showing a fourth embodiment of the present invention.

FIGS. 7A, 7B, and 7C are perspective views each showing an example of use of a conventional heat sink.

FIG. 8 is a front view showing a state where a gap is formed between the heat sink and the semiconductor device body when a conventional heat sink is used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor device 2 Semiconductor device main body 3 Heat sink 3a Radiation fin 4 Screw 5 Heat sink 6 Semiconductor chip 10 First heat sink 11 Mounting surface 12 Opposite surface 13, 13A Extension part 20 Second heat sink 21 Heat radiation Fin 22, 22A cavity 23 upper outer surface 24 space

Claims (7)

[Claims] 1. A heat sink attached to a semiconductor device, the heat sink including a first heat sink and a second heat sink, facing a mounting surface on which a semiconductor device body is mounted. A first heat sink having a heat radiating portion extending from the opposing surface; and a second heat sink disposed immediately below the opposing surface of the first heat sink. Heat sink for semiconductor devices. 2. The heat sink for a semiconductor device according to claim 1, wherein a material of said first heat sink is copper. 3. A first heat sink having a heat radiating portion extending from an opposing surface opposite to a mounting surface on which a semiconductor device main body is mounted, and disposed immediately below the opposing surface of the first heat sink. A second heat sink, and a semiconductor device body mounted on the mounting surface of the first heat sink.
A fixed semiconductor device. 4. The heat sink for a semiconductor device according to claim 1, wherein an opposing surface of said first heat sink and an outer surface of said second heat sink are brought into close contact with each other. 5. The semiconductor according to claim 1, wherein a predetermined space is formed between a facing surface of said first heat sink and an outer surface of said second heat sink. Heat sink for equipment. 6. The heat sink for a semiconductor device according to claim 1, wherein said second heat sink disposed immediately below said first heat sink has a plurality of radiating fins.
sink. 7. The second heat sink disposed immediately below the first heat sink is formed in a box shape having a single cavity or a plurality of slits. Item 6. A heat sink for a semiconductor device according to Item 1.