Bottom-up filling of Through Silicon Via (TSV) with Parylene as sidewall protection layer

In this paper, we present our recent advances in streamlining via-last TSV process flow. Parylene deposition, which is of excellent conformability to the substrate landscape, was introduced into TSV blind via filling process to realize uniform sidewall protection. Simulation was made to analyze the impacts of Parylene sidewall on the electric field distribution inside a blind via with high aspect ratios during electroplating, which indicates that a uniform plating current density distribution may be achieved with the help of the Parylene sidewall, and thus a void-free filling can be guaranteed. Then in experimental microfabrication runs, with Parylene sidewall protection, we achieved bottom-up filling of blind TSV of large ratio aspect at a higher rate. Besides, during our experiments, a “bottom-up plus non-bottom-up” filling methodology is proposed and the microfabrication trials demonstrate its potential capability of filling TSV blind via at a much higher rate.