Modeling the bottom-up filling of through silicon vias with different additives

The superfilling of through silicon vias (TSVs) is a technical challenge for the fabrication of modern 3D Electronic packaging. In order to achieve void-free-filling for TSVs with different aspect ratios, various organic additives need to be added into the plating bath. Since TSV filling is a complex electrochemical and physical process, it is difficult and very time-consuming to get an optimal additive ratio through experiments. So, numerical simulation will play an important role in the optimization of vias filling. To explain the mechanism of void-free filling, different models have been developed recently. In this paper, a numerical model was built to simulate the electroplating process in different conditions. The arbitrary Lagrange-Eulerian (ALE) method for solving moving boundaries in Finite Element Method (FEM) was used for the simulation. Since the working mechanism of the additives is still not totally clear, the results in this study try to explain the roles of different additives qualitatively. The tool used in this experiment is Comsol Multiphysics, a commercial FEM software. The parameters used in this study are based on the experimental results or published literatures.