Risk assessment of bond pad stacks: Combined utilization of nanoindentation and FE-modeling

Wire bonding as well as wafer probing can lead to oxide layer cracking. In combination with metal migration electrical failures may occur. Loading conditions comparable to the wire bonding process can be achieved using a nanoindenter. In this work a spherical tip has been used at first to determine material properties of the silicon nitride film and also to attain cracking of the film material. Based on the experimental results a finite element model using ABAQUS standardTM was established representing the experimentally observed load-displacement behavior. The introduction of the extended finite element method as well as the cohesive surface approach allow to describe different failure modes. The results of these investigations can be used to avoid failures like oxide layer cracking during wire bonding or during the wafer testing process.