Solder ball land metal structure of ball grid semiconductor package

Abstract

A solder ball land metal structure of a ball grid array semiconductor package capable of obtaining a maximum contact area between a solder ball land metal element and a solder ball fused on the land metal element. A solder mask defined type land metal structure according to the present invention has a single etching hole at the central portion thereof or a plurality of etching holes at the outer portion thereof in order to obtain an increased contact area for a solder ball. Each etching hole extends from the upper surface of the land metal element to the upper surface of the BT substrate throughout the land metal element or extends from the upper surface of the land metal element to a depth corresponding to about half the thickness of the land metal element. Each etching hole serves as a locking hole for fixing the fused solder ball. Thus, it is effectively prevent the solder ball from being separated from the land metal element. A non-solder mask defined type land metal structure according to the present invention has a plurality of tooth-shaped radial extensions provided at a land metal element having a conventional structure. The extension are interposed between a BT substrate and a solder mask. By such a configuration, it is effectively prevent the solder ball and land metal element from being separated from the BT substrate.

Dependencies are inferred from the claim text.