Process solutions and polymer materials for 3D-WLP through silicon via filling

This paper deals with the development of a process for medium density through silicon via (TSV) polymer filling. This solution is driven by reliability considerations. Firstly, a set of specifications concerning the polymer selection is presented. Secondly, the process optimization with two kinds of polymers is presented: a liquid resin and a dry film resist. Issues with both of the solutions are also discussed. Different types of TSV are studied (shapes and dimensions). Finally, material characterizations are achieved in order to determine the ability of the polymer to be integrated in the TSV and 3D stacking processes. Other characterizations will be useful for further thermo-mechanical studies.