JPS5980949A - Resin-encapsulated semiconductor device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an IC, L, in which the entire semiconductor substrate is molded with resin.
This relates to the structure of resin-sealed semiconductor devices such as SI.

The structure of a semiconductor device molded with resin is shown in FIG. 1, in which a semiconductor substrate 2 is placed between a tab 3 made of a metal plate.
It is suspended by resin 1 while being fixed to. Since the mold resin 1, the semiconductor substrate 2, and the tab 30 have different linear expansion coefficients, thermal stress occurs in each component due to temperature changes. The metal plate tab 3 used here is formed by punching a single metal plate together with the lead 4 shown in FIG. For this reason, a sharp burr 6 remains at one corner of the tab as shown in FIG. In the prior art, the semiconductor substrate was fixed to the surface opposite to the surface where the burr 6 remained, and then molded with resin. For this reason, high stress concentration occurred around the tab, and breakage points 7 were likely to occur in the mold resin.

An object of the present invention is to prevent mold resin from breaking in a semiconductor device molded with resin.

The present invention was made as a result of analyzing the stress generated in the vicinity of the tab of a semiconductor device molded with resin. According to the present invention, the semiconductor substrate 2 is fixed to the tab surface with sharp corners such as burrs 6 of the tab 3 around the periphery, as shown in FIG. 3, as a means of reducing the high stress generated at the corners of the tab.

The cheapest and most mass-producible processing method for producing tabs and lead frames from metal plates is the die-cutting method. According to this processing method, one of the angles formed between the side surface and the front and back surfaces of the punched plate becomes a sharp corner like a burr 6, and the other becomes a curved surface due to the plastic flow of the metal. Therefore, by positioning the curved square semiconductor substrate on the opposite side to the surface to which it is fixed, the stress concentration can be reduced.

Furthermore, if the burr 6 is located on the side where a semiconductor substrate with a sharp corner is fixed, high stress concentration due to the burr 6 can be prevented since the burr 6 is located near a semiconductor device with a high elastic modulus. can. This eliminates the need for tab deburring and corner rounding.

An embodiment of the present invention will be explained with reference to FIGS. 3 and 4.

The semiconductor substrate 2 is fixed to the burr side of the tab 3,
The entire body is molded with mold resin 1. The radius of curvature R of the corner of this tab 3 opposite to the surface to which the semiconductor substrate Z is fixed is 0.02111. Comparing the stress at the corner of the tab in this example with the stress at the corner of the conventional product, it was found that the stress in this example was reduced by nearly 30% compared to the conventional product.

According to the present invention, it is possible to reduce the concentration of stress occurring at the corners of the tab 3 in the semiconductor device, thereby preventing the mold resin from breaking. As shown in FIG. 3, if the distance L1 from the surface of the tab 3 with the sharp corner 6 to the resin surface is greater than the distance from the opposite surface of the tab 30 to the resin surface (back surface), the semiconductor The reliability of the device is the same as above. That is, by increasing the distance from the part of the resin where stress tends to concentrate to the resin surface, even if a local fracture occurs in the resin, the fracture is less likely to reach the resin surface. As a result, K is set such that the semiconductor substrate can be sufficiently protected from contamination from outside the sealing resin.

Further, there is no need to deburr or round the corners of the punched tab.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional perspective view of an LSI packaged by resin molding, FIG. 2 is a cross-sectional view of a conventional product, FIG. 3 is a cross-sectional view of an embodiment of the present invention, and FIG. 4 is a portion of an embodiment of the present invention. FIG. 1...Mold resin, 2...Semiconductor substrate, 3...
Tab, 4...Lead frame, 5...Leader line, 6
...Burr, 7...Broken point. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. A resin-sealed semiconductor device in which a semiconductor substrate is fixed onto a tab made of a metal plate, and the tab and the semiconductor substrate are sealed with resin, the tab being y-orthogonal to the main surface thereof. The semiconductor substrate has a side surface, a corner that is a sharp corner between the main surface and the side surface, and a corner that is gently curved between the surface opposite to the main surface and the side surface. is fixed to the main surface.