JPH0917920A - Semiconductor element cooling heat sink - Google Patents

Abstract

PURPOSE: To improve heat dissipation property without enlarging a configuration of a heat sink body at all by forming a hollow part inside a heat sink body and enclosing liquid which is gasified by heat generation of a semiconductor element in the hollow part. CONSTITUTION: A heat sink body 1 consists of aluminum and almost an entire of an inside thereof is formed as a hollow part 2. One outer surface of the body 1 is a plane since it becomes an attaching surface of a semiconductor element 4, and the other surface which becomes a heat dissipation part is provided with a fin 3 which projects to an inside of the hollow part 2 for raising heat conduction efficiency. The hollow part 2 is charged with liquid perphlorocarbon 5 and is sealed. Therefore, according to this constitution, a weight can be greatly reduced when compared to a heat sink of the same configuration whose body 1 is all formed of aluminum. Thereby, it is possible to improve heat dissipation property without enlarging a configuration of a device at all.

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 cooling semiconductor elements such as transistors and diodes used in power supply devices, control devices and the like in all fields, regardless of whether they are for commercial or industrial use.

[0002]

2. Description of the Related Art A mold type semiconductor element such as a diode has a decrease in capability when the temperature rises during use.
If it is terrible, it will be destroyed.

Therefore, conventionally, in order to cool the semiconductor element,
A heat sink integrally formed of an aluminum material or the like having good heat conduction by an extrusion die is used, and the semiconductor element is closely attached to the opposite side of the heat dissipation portion of the heat sink.

Due to this close contact structure, the heat generated from the semiconductor element is radiated into the air through the heat sink.

[0005]

However, since the conventional heat sink is made of metal, it is necessary to make its shape large in order to improve the heat dissipation characteristics, which increases the weight and volume. There was a problem that it would end up.

The present invention seeks to provide a heat sink.

[0007]

Therefore, in the heat sink for cooling a semiconductor element according to the present invention, a hollow portion is formed in the heat sink body, and a liquid that is vaporized by the heat generated by the semiconductor element is sealed in the hollow portion. It is characterized by

Here, the liquid is a liquid at room temperature, but a substance having a boiling point such that it is vaporized by the heat generation of the semiconductor element is used. Generally, the heat generated by semiconductor devices is about 40-100
Since it is ℃, it is possible to cite, for example, CFCs (especially R113), alcohols (especially methanol), acetone, perfluorocarbons, water, etc., which have a boiling point in that temperature range. From the viewpoint of corrosion resistance of the heat sink body, liquids other than water are preferable.

[0009]

The heat sink body of the present invention has a hollow interior, and a liquid that is vaporized by the heat generated by the semiconductor element is sealed therein. Therefore, even if the shape is increased, the weight can be significantly reduced as compared with the case where the main body is entirely made of metal.

When a semiconductor element is attached to such a heat sink, the heat in the semiconductor element causes the liquid in the hollow portion to reach the boiling point and vaporize. At that time, the heat of vaporization is taken away and the heat is conducted to the heat radiating portion of the heat sink body. However, since the transfer medium is a liquid or a gas, it is extremely fluid and efficiently conducts the heat. The heat that has been satisfactorily transferred is radiated from the heat radiation portion.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a heat sink showing a first embodiment. The heat sink body 1 is made of aluminum, and the inside thereof is formed as a hollow portion 2 which is almost hollow. One of the outer surfaces of the main body 1 is the semiconductor element 4
Although it is a flat surface because it serves as the mounting surface, the fins 3 that project to the inside of the hollow portion 2 are formed on the other surface that serves as a heat dissipation portion in order to enhance heat transfer efficiency. Liquid perfluorocarbon 5 is filled and sealed in the hollow portion 2.

FIG. 2 is a perspective view of a heat sink showing a second embodiment, FIG. 3 is a third embodiment, and FIG. 4 is a fourth embodiment. The internal structure of the main body 1 is similar to that of the first embodiment, but the outer shape of the main body 1 is different. That is, in the second embodiment, the fin 3 in the first embodiment is formed into a pin shape, and in the third embodiment, the comb-shaped projection 6 is formed on one side of the main body 1 by extrusion molding. In the fourth embodiment, the fin 3 of the first embodiment is pin-shaped on one side of the main body. Particularly, in the third embodiment, the inside of the protrusion 6 is used, and in the fourth embodiment, the fin 3 is used.
The inside is also hollow and integrated with the hollow portion 2.

In the embodiment of the present invention as described above, the hollow portion 2 is formed in the inside thereof, and the liquid perfluorocarbon 5 is filled and enclosed therein. The weight can be significantly reduced compared to the one formed by.

When the semiconductor element 4 is attached to the above embodiment as shown in FIG. 1, the liquid perfluorocarbon 5 enclosed in the hollow portion 2 reaches the boiling point and is vaporized by the heat generation of the semiconductor element. At that time, the heat of vaporization is removed while the heat is dissipated from the fins 3 or the protrusions 6 which are the heat radiation portion of the heat sink body 1.
It is conducted to and is radiated from there. At this time, since the perfluorocarbon 5, which is a transmission medium, is a liquid or a gas, it is extremely rich in fluidity and efficiently conducts heat.

[0016]

As described above, according to the heat sink for cooling the semiconductor device of the present invention, the heat dissipation characteristics can be improved without increasing the size of the heat sink.

Even if the shape is enlarged to further improve the heat dissipation property, the weight can be greatly reduced because the inside is hollow and only the liquid is enclosed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment.

FIG. 2 is a perspective view showing a second embodiment.

FIG. 3 is a perspective view showing a third embodiment.

FIG. 4 is a perspective view showing a fourth embodiment.

[Explanation of symbols]

 1 Heat sink body 2 Hollow part 3 Fin 4 Semiconductor element 5 Liquid perfluorocarbon 6 Protrusion

Claims (1)

[Claims] 1. A heat sink for cooling a semiconductor element, wherein a hollow portion is formed in a heat sink body, and a liquid which is vaporized by heat generation of the semiconductor element is enclosed in the hollow portion.