Last Metal Copper Metallization for Power Devices

摘要

High current-carrying capacity and low resistivity are key parameters for power devices. In this paper a copper based terminal metallurgy scheme for wire- and wedge-bonding is described, which improves these properties. The method of choice for depositing thick copper wires is pattern plating. However the plating process has to be optimized in order to get a homogeneous thickness distribution. An electroless coating of NiP, Pd and Au on top of the Cu layers is used as bond interface. This process provides high reliable gold-wire and aluminum-wedge bonds.