Bonding Wires For Power Modules: From Aluminum To Copper

Interconnections on the top surface of the chip are now limiting the lifetime of power modules. It is necessary to evaluate the die top interconnection technologies in order to help module manufacturers to find a solution to prolong the lifetime of power modules. In this review, the reliability performance of different die top interconnections, such as Al bond wires, Al-clad Cu bond wires and Cu bond wires are compared. The Cu wire bonding shows the best power cycling capability among the interconnection materials. The failure mechanism has been changed from the bond wire lift-off to the substrate fatigue. The substrate becomes the limitation of the lifetime of power modules.