JPH0383366A - Semiconductor device - Google Patents

Abstract

PURPOSE:To alleviate a stress to be concentrated at the corner part of a die pad and to reduce cracks by rounding the corner. CONSTITUTION:A roundness 11 is formed at the corner part of a die pad 14 to reduce cracks from the corner part. The larger the radius of curvature of the roundness of the corner is, the more the effect appears. Accordingly, the maximum radius of curvature become half the thickness of the pad.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a resin-sealed semiconductor device, and more particularly to a method for reducing cracks occurring at the corner portions of a die pad.

BACKGROUND OF THE INVENTION In recent years, surface mounting methods have rapidly become popular for high-density mounting of semiconductor devices. The biggest problem with surface mounting is that the entire package is suddenly exposed to high temperatures of 215°C to 260°C. Due to this rapid thermal stress, the moisture absorbed by the package's sealing resin and segregated at the interface between the die pad and the resin turns into water vapor, causing separation at the interface, and the vapor pressure that evaporates and expands causes swelling at the bottom of the die pad, and finally Cracks begin to occur at the corners of the die pad where stress is most concentrated.

FIG. 2 is a cross-sectional view of a conventional semiconductor device, in which 1 and 2 are lead frames, 3 is a die pad, 4 is a semiconductor chip, 5 is a sealing resin, 6 is an interface between the die pad and the sealing resin, and 7. The part numbered 8 is the corner part where stress tends to concentrate.

In the semiconductor device configured as described above, the conventional die pad is formed by punching or the like, and therefore has a structure with sharp corners.

Problems to be Solved by the Invention However, the above-mentioned conventional technology has a problem in that stress is concentrated at the corner portions of the die pad, and cracks are likely to occur from those portions.

The present invention solves the above-mentioned conventional problems, and aims to provide a semiconductor device having a structure in which cracks are less likely to occur at the corner portions of a die pad.

lIl! Means for Solving the Problem In order to achieve this object, the present invention has rounded corners of the die pad to relieve stress concentrated on itself and reduce the occurrence of cracks. It is.

Effect: With this configuration, the roundness provided at the corners of the die pad attempts to relieve stress concentration, so that it is possible to reduce clarifications that occur at the corner portions of the die pad.

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

FIG. 1 shows a cross-sectional view of a semiconductor device according to an embodiment of the present invention. In FIG. 1, 9 and 10 are lead frames, 11 is a rounded part of the die pad,
Reference numeral 12 represents a semiconductor chip, and reference numeral 13 represents a sealing resin, which have the same structure as the conventional example. In FIG. 1, 14 is a die pad with rounded corners. The thicker the radius of curvature of the corner, the greater the effect. Therefore, the maximum radius of curvature is half the thickness of the die pad.

As described above, according to this embodiment, the roundness provided at the corners of the die pad prevents stress concentration, so that it is possible to reduce the occurrence of cracks that occur from the corners of the die pad. This roundness can be effective by simply cutting off the corners and making it into a polygon, but it is more effective to round it. Also, in order to obtain effective results, the minimum radius of curvature must be greater than or equal to 30 μm.

Effects of the Invention As described above, the present invention can reduce the occurrence of cracks from the corner portions of the die pad by rounding the corner portions of the die pad. Further, since only the die pad is different from the conventional one, the conventional molding device can be used without any change in the bulk caging process.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a semiconductor device in an embodiment of the present invention;
FIG. 2 is a sectional view of a conventional semiconductor device.

Claims (1)

[Claims] A semiconductor device characterized in that by rounding the corners of the die pad, cracks that occur from the corners of the die pad toward the sealing resin are reduced.