JPS61256749A - Resin case of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent cracks, by providing grooves, which are communicated to the outer edges of a bottom plate, at a parts of tightening holes in the bottom plate of a resin case, thereby releasing stress and strain accompanied by the deformation of the case. CONSTITUTION:Grooves 20 and 20a, which are communicated to the edges of a bottom plate, are provided at parts of tightening screws 8 and 8a are inserted through the holes 3 and 3a and tightened to a heat radiating fin 9. Then, stress and strain yielded in the bottom plate 2 are released to the grooves 20 and 20a. Therefore, cracks are not yielded in the bottom plate 2 itself.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a resin case for a semiconductor device.

[Conventional technology]

FIG. 3 is a perspective view of a conventional resin case for a semiconductor device, and FIG. 4 is a bottom view thereof. In both figures, (1) is the resin case, (2) is the bottom plate of the resin case (1), and (3) is the resin case.

(3a) are fastening holes provided on both sides of the bottom plate (2).

The conventional resin case (1) of a semiconductor device is constructed as described above, and in order to store and use a semiconductor element in the resin case (1), as shown in FIG. 2) On the back side of the bottom plate (2), tighten the holes (3) and (3a).
Tighten the holes (4J, (4a) in the same position as the number of holes) and fix the heat plate (5) with adhesive (6).Next, connect each other with wiring and connect the terminals (7) of the nine semiconductor elements. is housed in the resin case (1) so as to protrude outward from the resin case (1), and is covered with mold resin to isolate it from the outside environment.

In this way, the semiconductor element is housed, the heat sink (5) is attached and fixed, and the resin case (1) is then tightened with the tightening screws (8) and (8a) as shown in Figure 6. Hole (3), (4)
.

(3a) and (4a) and tightened to the radiation fin (9) with a torque of 20 to 30 Kf-α to form a semiconductor device. As a result, heat generated by the semiconductor device is dissipated from the heat radiation fins, thereby preventing malfunctions and failures due to heat generation. However, as shown in Figure 7, the tightening screw (8)
By tightening (8a), the bottom plate (2) of the resin case (1)
A crack α0 may occur at the end of the plate.

[Problem that the invention seeks to solve]

The resin case (1) for the semiconductor device described above needs to be molded from a synthetic resin that has excellent heat resistance and mechanical properties, and has almost no gas permeability. Since it is difficult to obtain excellent synthetic wood,
Generally, it is molded from polypterene terethalate (PBT) resin, which has excellent mechanical properties and has no gas permeability. Polyphenylene sulfide (PPS) 411., which has excellent heat resistance, is used in relation to the heat generation amount of semiconductor devices.
It may also be molded with J-boxy resin or the like. However, in either case, warping is likely to occur after molding, and therefore, cranking is likely to occur when fastened to the heat radiation fin.

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to obtain an inexpensive resin case for a semiconductor device that does not cause cracks when fastened.

[Elaborate means to solve problems]

In the resin case for a semiconductor device according to the present invention, a part of the fastening hole provided in the bottom plate is provided with a groove that communicates with the edge of the bottom plate.

[Effect]

In this invention, even if the resin case housing the semiconductor device is tightened to the heat dissipation fin with a tightening screw through a hole, stress and distortion due to deformation of the resin case escapes to the resin case. No cracks will occur.

〔Example〕

FIG. 1 is a perspective view of an embodiment of the invention, and FIG. 2 is a bottom view thereof. In the figure, the frame (20a) is a groove that communicates a part of the tightening hole (3), (3a) with the edge of the bottom plate (2) of the resin case (1). This ditch.

To provide (20a) on the bottom plate (2), use the '-% groove (a).
, (20a) 'For tightening, use holes (3), (3a
) is integrally molded, or the resin case (1a) has holes (3), (3+!L) for tightening.

Cut out part (20a).

The resin case (1a) is generally made of synthetic resin such as polybutylene terephthalate (PBT), but if heat resistance is required, polyphenylene sulfide (PPS) resin or epoxy resin may be used. use

To attach the resin case (1) configured as described above, apply adhesive (6) to the bottom surface of the resin case (1a) and the surface of the heat sink (5) in advance, and heat it in an oven. to secure both. However, in the case of a reactive adhesive, both can be fixed without heating. Next, the semiconductor elements connected to each other by wiring are housed in the resin case (1a) with the terminals ( ) 1 protruding to the outside.
Epoxy resin or the like is injected to protect the semiconductor element by insulating it from the outside atmosphere. In order to further dissipate heat generated from the semiconductor device, the semiconductor device completed by housing the semiconductor element in the resin case (1a) is fitted with tightening screws (8) and (8a) as shown in FIG. Tighten the hole (
3) and (3a) and is fastened to the heat radiation fin (9). However, when tightening the tightening screws (8) and (8a),
Stress and strain generated in the bottom plate (2) of the resin case (1a) escapes to the grooves (A) and CZoa), so the bottom plate (2)
No cracks will occur in itself.

In the above explanation, the semiconductor element housed in the resin case (1a) K is a transistor module.
It can also be applied when a thyristor module, diode module, hybrid IC, etc. are housed in a resin case (1a).

〔Effect of the invention〕

As explained above, in this invention, the resin case can be tightened by providing a groove in a part of the hole that communicates with the edge of the bottom plate of the resin case, so the resin case can be tightened with a tightening screw through the hole and onto the radiation fin. No cracks will occur in the bottom plate even when tightened. In addition, even if a resin case made of synthetic resin, which has excellent heat resistance but is brittle, is fastened to a heat dissipation fin, no cracks will occur, so it can be applied to semiconductor devices that generate a large amount of heat. There is.

[Brief explanation of the drawing]

Figure 1 is a perspective view of an embodiment of the present invention, Figure 2 is a bottom view, Figure 6 is a perspective view of a conventional resin case, Figure 4 is a bottom view, and Figure 5 houses a semiconductor element. Figure 6 is a side sectional view showing a conventional resin case housing a semiconductor element fixed to a heat radiation fin; Figure 7 is a partial perspective view of the state shown in Figure 6. It is. In the figure, (1), (1a) are the resin case, (2) is the bottom plate, (3), (3a), (4), (4a
) is the hole for tightening, (5) is the heat sink, (6) is the adhesive, (7
) Vi terminal, (8), (8a) is the tightening screw, (9
) are heat radiation fins, (1), (20a) are Vi grooves. In each figure, the same reference numerals indicate the same or corresponding parts. Agent: Patent Attorney Tadashi Sato Figure 1 Figure 3

Claims (1)

[Claims] A structure in which a plurality of semiconductor elements connected to each other by wiring are housed in one resin case, the resin case is filled with molded resin to isolate it from the external atmosphere, and the resin case is attached to a heat radiation fin with screws. 1. A resin case for a semiconductor device according to claim 1, wherein a part of a tightening hole provided in a bottom plate of the resin case is provided with a groove communicating with an outer edge of the bottom plate.