Method for forming multilayer indium bump contacts

摘要

A method for forming multilayer bump contacts for use in flip-chip bump bonding and the like. The method comprises applying a base layer to a substrate and then applying a malleable conductive layer to the base layer. In a first embodiment, individual bump contacts are formed by removing portions of the base layer and malleable layer such that a plurality of bump contacts are formed. In a second embodiment a photoresist and etching process is used. The need to precisely align a mark to define the position of the malleable layer relative to the base layer is eliminated since the positions of the malleable layer and the base layer are defined simultaneously in both embodiments. Thus, the number of process steps is reduced, yield is increased, and alignment accuracy is improved.