JPH03250650A - Heat sink for semiconductor device - Google Patents

Abstract

PURPOSE:To improve the adherence property between resin and a heat sink and moisture protection and to prevent the generation of resin burr on the back side of a header which obstructs lowering temperature resistance by installing a collar provided at the tip within a resin mold region on the top of the heat sink. CONSTITUTION:A semiconductor chip 7 is installed to a thick board header (in radiation shape). After each electrode of the chip is bonded with inner leads 2a, the header is partially molded with resin in such a manner that the semiconductor chip and the inner leads are enclosed. The tip of the header in a resin mold region (in chain line 8) is squeezed so as to provide 'collar', thereby producing a projection part 9. The projection part serves to enhance the bonding property between the resin and the header to a satisfactory extent.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to resin-sealed semiconductor devices. This invention relates to a heat sink for a manufactured package.

Two-Plate Structure [Prior Art] Regarding a resin-sealed semiconductor package with a two-plate structure that combines a heat dissipation plate (thick metal plate header) for attaching a semiconductor element and a member to be fixed such as a lead (lead frame), As described in Japanese Unexamined Patent Publication No. 57-155755, an embossing technique is used to caulk and fix a heat dissipation plate (header) and a lead frame using the protrusions of the header.

[Problem to be solved by the invention]

In resin-sealed semiconductor packages, the adhesion between the heat sink on which the elements are attached and the resin that covers it is not always sufficient, and peeling occurs between the two, allowing water etc. to enter through the gap. There was a problem in that the internal semiconductor elements were affected by corrosion and deterioration. In the conventional technology described above, holes (X3 holes) are made in the resin mold area of the heat sink as a means to improve the adhesion between the resin and the header and to prevent the header from peeling off from the resin due to shrinkage when the resin mold hardens. A portion of the resin was embedded there.

However, when holes are made in the heat sink, resin bulges are likely to occur on the uneven back surface of the header, which adversely affects thermal resistance during operation.

Additionally, extra work was required to remove this resin burr.

The present invention has been made to solve the above-mentioned problems, and its purpose is to improve moisture resistance by improving the adhesion between the resin and the heat sink in a resin-sealed package with a two-plate structure. [Means for Solving the Problems] In order to achieve the above object, the present invention provides a structure that does not produce resin burrs on the back side of the header, which hinders reduction in thermal resistance. , and a member to be fixed, such as a lead, in a resin-sealed package having a two-plate structure, which has a flange at the tip within a resin molded area on the upper surface of the heat sink.

The present invention also provides that the protrusion is formed on the heat sink G of the package by embossing and crushing.

[Effect]

The resin mold area on the surface of the heat sink is embossed to provide a protrusion, and the tip is closed to create an umbrella-like shape, thereby increasing the adhesion between the resin and the surface of the heat sink after molding. This can prevent the resin from peeling off from the heat sink due to curing shrinkage of the resin. In particular, it is possible to effectively prevent peeling due to stress when the heat sink is mounted on a wiring board with screws.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of a structure in which a header and a lead frame for one unit of a two-plate semiconductor package are combined.

1 is a thick plate header (heat sink), and a semiconductor chip (7) mounting portion is provided in the center thereof.

2B lead group, each lead is inner-1-
A saw 1' frame 5 is constructed by integrally connecting a plurality of leads with a dam 3 intersecting these leads and a frame 4 surrounding the periphery.

This lead frame is fixed by embossing and tightening with protrusions 6 on both sides (outside the resin mold area) of the thick plate header 1, thereby forming a semiconductor package substrate having a two-plate structure.

After the semiconductor chip '7 is mounted on the header and bonding is performed between each electrode of the chip and the inner lead 2a, a part of the header is molded with a resin body so as to surround the semiconductor chip and the inner lead. .

In this invention, within the resin molded area (dashed line 8) of the header, there is a protrusion 9 whose tip is crushed and has a "bubble" shape.
is provided, and this protrusion improves the bondability between the resin and the resin.

FIG. 2 shows an enlarged view of the emboss crushing protrusion 9, with (a) being a plan view and (b) being a sectional view.

As shown in (b), the umbrella-shaped portion 10 is formed by embossing from the lower surface side of the header.

In the conventional structure in which the thick plate header 1 and the resin molded body 8 are in close contact with each other only around the soda, the screw hole (11) side of the header is open, and the resin is removed during the molding process during assembly. A gap is likely to occur between the header surface and the resin due to curing shrinkage, and when screwing is done for mounting on a completed wiring board, a large stress is applied to the header screw hole, causing a gap between the header and the resin. Peeling may occur. However, in the present invention, the resin molded area of the header is embossed on the part near the large screw side, and the protrusion 9 is crushed to provide an umbrella-shaped part 10, thereby suppressing stress when the resin hardens and shrinks. , is effective in further improving adhesion with resin.

Fig. 3 shows another embodiment in which other parts such as rivets J12 with umbrella-shaped parts are driven into the holes drilled in the header instead of embossing. This is an example in which the same effect as embossing was achieved.

〔Effect of the invention〕

According to the present invention, the conventional embossing process for joining the header and lead frame can be used as is, and the structure is as simple as providing a protrusion in a part of the resin molded area of the header and crushing the tip of the protrusion. As a result, the header can be manufactured in one line using a press mold for manufacturing the header.

This protruding part maintains adhesion with the resin by providing an umbrella part, and since there is no part that directly affects the assembly process, there is no need for strict standards that require processing precision, etc., making it easy to manufacture. It is.

[Brief explanation of drawings]

FIG. 1 shows one embodiment of the present invention, and is a plan view of a resin-sealed package having a two-plate structure. FIG. 2 is a longitudinal sectional view of the embossed brim protrusion in FIG. 1. FIG. 3 shows another embodiment of the present invention, and is an enlarged longitudinal cross-sectional view of a protrusion formed by re-grooving. 1... Thick plate header (heat sink), 2... Lead, 3
...Dam, 4.Frame, 5.Lead frame 6..Protrusion connecting header and frame, 7.
・・Semiconductor chip, ・・Resin mold area, 9・・
・Emboss crushing protrusion, 10... Umbrella-shaped portion, 11・
...Screw hole, 12...Rivet.

Claims (1)

[Scope of Claims] 1. In a resin-sealed package with a two-plate structure consisting of a heat sink to which a semiconductor element is attached and a member to be fixed such as a lead, a flange is provided at the tip within the resin molded area on the upper surface of the heat sink. A heat dissipation plate for a semiconductor device, comprising: 2. In the heat dissipation plate for a semiconductor device according to claim 1, the protruding portion is provided on a side closer to a screw hole portion of the header. 3. In the heat dissipation plate for a semiconductor device according to claim 1 or 2, the protruding portion is formed by crushing the tip of the embossed portion.