JPS60169156A - Cooling-fin attaching structure of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the mutual bridge of solders, when soldering an electrode metal plate and a cooling fin, by making the thickness of a part of an electrode metal plate corresponding to the metallized part of the insulating main surface of an insulating plate thicker than the other part, and forming a cross sectional shape, which is protruded to the insulating side. CONSTITUTION:A part of an electrode metal plate 1A corresponding to the metallized part of the main surface of an insulating plate 3 is made thicker than the other part. A cross sectional structure, which is protruded to the side of the plate 3 is formed. Therefore, the gap between the metal plate 1A and a cooling fin 2 becomes wide at the part outside the periphery of the plate 3. The mutual welding of solders 4a and 4b, which solder the fin 2 and the metal plate 1A, becomes less, and the insulating function of the plate 3 is maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in the structure of a semiconductor device, in which cooling fins are attached to an electrode plate.

[Prior art]

Figure 1 is a cross-sectional view showing the structure of a cooling fin with a throat in a conventional semiconductor device. fins, (3) is an insulating plate, (4a) and (4b) are soldered between the metal plate (1) and the insulating plate (3) and between the insulating plate (3) and the cooling fin (2), respectively. This is solder.

In this way, an insulating plate (3) such as a ceramic plate is provided between the metal plate (1) and the cooling fins (2) for electrical insulation.
), but in the above conventional structure.

Because the distance between the metal plate (1) and the cooling fins (2) is small.

As shown in Figure 2, when the solder (4a) and (4b) slightly flow out to the surrounding area, they immediately weld to each other and the insulating plate (
There was a drawback that the insulating effect of 3) was completely lost.

[Summary of the invention]

This invention has been made in view of the above points, and the thickness of the portion of the electrode metal plate corresponding to the metallized portion of the main surface of the insulating plate is increased so that the cross-sectional shape protrudes toward the insulating plate side. This provides a structure in which the cooling fins are pressed against the electrode plate in which mutual welding of the solders on the main surface side of the insulating plate is less likely to occur.

[Embodiments of the invention]

FIG. 3 is a sectional view showing the structure of an embodiment of the present invention, in which the same reference numerals as in the conventional example of FIG. 1 indicate equivalent parts. (1 person) is the electrode metal plate in this example, and the thickness of the part corresponding to the metallized part (in the figure, excluding the peripheral part) of the main surface of the insulating plate (3) such as a ceramic plate. Make it thicker;
It has a cross-sectional structure that protrudes toward the insulating plate (3) side. Therefore, the gap between the electrode metal plate (IA) and the cooling fins (2) becomes wider in the area outside the periphery of the insulating plate (3).
Welding of the solders (4a) and (4b) to each other becomes extremely rare, and the insulating function of the insulating plate (3) is maintained.

Note that the present invention can be widely applied to general semiconductor devices such as transistors, thyristors, and diodes.

〔Effect of the invention〕

As explained above, in the present invention, the cooling fin mounting structure is such that the cooling fin is attached by sequentially soldering the insulating plate and the cooling fin to the electrode metal plate of the semiconductor device. The thickness of this part is made thicker than other parts, and the cross-sectional shape protrudes toward the insulating plate, so in the part outside the periphery of the insulating plate, the gap between the electrode metal plate and the cooling fin is wide, and the insulating plate Mutual welding of the solders on both sides is less likely to occur, and the defective rate can be reduced.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing the structure of a conventional semiconductor device with cooling fin holes, and Fig. 2 is a cross-sectional view showing the situation in which defects occur.
FIG. 3 is a sectional view showing the structure of an embodiment of the present invention. In the figure, (IA) is an electrode metal plate, (2) is a cooling fin, (3) is an insulating plate, and (4a) + (4b) is a solder. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent Masuo Oiwa

Claims (2)

[Claims] (1) In a structure in which an insulating plate and cooling fins are sequentially soldered to an electrode metal plate of a semiconductor device. A semiconductor device characterized in that the electrode metal plate has a cross-sectional shape that protrudes toward the insulating plate by making the portion of the electrode metal plate that faces the metallized portion of the main surface of the insulating plate thicker than other portions. The cooling fin mounting structure. (2) A cooling fin attachment structure for a semiconductor device according to claim 1, wherein the insulating plate is a ceramic plate.