Patent ID: 7679185

Claim:
A microcircuit package comprising: a substrate having a first surface, said substrate formed of copper, a copper alloy, silver or a silver alloy; a layer of ductile material having a first surface and a second surface, the first surface of the layer attached to the first surface of the substrate; a barrier layer having a first surface and a second surface, the first surface of the barrier layer attached to the second surface of the layer of ductile material; a gold layer having a first surface and a second surface, the first surface of the gold layer attached to the second surface of the barrier layer; and a eutectic layer having a first surface and a second surface, the first surface of the eutectic layer attached to the second surface of the gold layer, said eutectic layer formed of a gold-tin (AuSn) alloy, a gold-silicon (AuSi) alloy or a gold-germanium (AuGe) alloy, said first surface of said eutectic layer for mounting a semiconductor die thereon.