Semiconductor chip package assembly with deflection- resistant leadfingers

Abstract

The invention relates to leadframes and semiconductor chip package assemblies using leadframes, and to methods for their assembly. A disclosed embodiment of the invention includes a semiconductor package leadframe with a chip mounting surface for receiving a semiconductor chip and a plurality of leadfingers. The leadfingers have a proximal end for receiving one or more wirebond, and a distal end for providing an electrical path from the proximal end. One or more of the leadfingers also has an offset portion at its proximal end for increasing the clearance between the leadfinger and underlying heat spreader, increasing the stiffness of the leadfinger, and increasing leadfinger deflection-resistance and spring-back. The offset is in the direction opposite the plane of a heat spreader thermally coupled to the mounting surface. Preferred embodiments of the invention further include a semiconductor chip affixed to the mounting surface and a plurality of bondwires operably coupling bond pads of the chip to the offset portions of the proximal ends of individual leadfingers.