Making semiconductor packages with stacked dies and reinforced wire bonds

Abstract

This invention provides a method for making a semiconductor package with stacked dies that substantially reduces risk of fracturing of the dies and prevents breakage of the wire bonds caused by wire sweep. One embodiment of the method includes the provision of a substrate and a pair of semiconductor dies, each having opposite top and bottom surfaces and a plurality of wire bonding pads around the peripheries of their respective top surfaces. One die is attached and wire bonded to a top surface of the substrate. A measured quantity of an uncured, fluid adhesive is dispensed onto the top surface of the first die, and the adhesive is squeezed out to the edges of the dies by pressing the bottom surface of the second die down onto the adhesive until the two dies are separated by a layer of the adhesive. The adhesive is cured and the second die is wire bonded to the substrate. A bead of an adhesive is dispensed around the periphery of the dies such that it covers the wire bonds and bonding pads on the second die. A plastic body is molded over the dies and the bead of adhesive. The bead of adhesive prevents bending or breakage of the wire bonds caused by wire sweep during the subsequent molding operation.