Clad bonding wire for semiconductor device

摘要

A clad bonding wire for electrically connecting the bonding pad of a semiconductor device to an external lead comprises a core wire formed on one of high-purity Pd or a Pd alloy, high-purity Au or a Au alloy, high-purity Pt or a Pt alloy, and high-purity Ag or a Ag alloy, and a cladding cladding the core wire and formed of another one of the foregoing materials other than that forming the core wire. The wire-to-cladding diameter ratio D2/D1 is in the range of 15% to 60% or 85% to 99. When the tip of the clad bonding wire is heated to form a ball, part of the core wire and part of the cladding in a neck formed behind the ball diffuse into each other to form an alloy of the materials forming the core wire and the cladding between the core wire and the cladding to enhance the mechanical strength of the neck beyond that of other portion of the clad bonding wire.