Material characterization for nano wafer level packaging application

As the feature size of integrated circuit (IC) packages needs to be decreased significantly, computational methods in conjunction with experimental data have been employed to study the mechanical issues, which have become a concern for the components reliability. In this paper, the issues associated with and experimental methods necessary to perform material characterization for nano-wafer level packaging application will be investigated. Firstly, the need for nano-indentation to accurately characterize the modulus and hardness of copper thin film will be presented. Furthermore, some of the problems such as strain rate and thickness effects associated with extracting the modulus using nano-indentation will be addressed. Lastly, results from a fatigue experiment on a 200 μm pitch solder column will also be given and factors affecting the failure criterion of these solder columns in fatigue conditions will be investigated.