Copper Electrodeposition Parameters Optimization for Through-Silicon Vias Filling

Abstract

Filling of Through-Silicon Vias (TSV) is governed, similarly to the well-known Damascene process, by several plating parameters and filling mechanisms. However, due to their larger dimensions, the diffusion of species into this particular type of via is becoming the main obstacle for the superfilling phenomenon generation. It is thus of prime importance to adjust the electroplating process parameters in order to take into account the TSV specificity. In this paper, the impact on the filling mechanism of four plating parameters - plating time, current density, wafer rotation and accelerator concentration - was investigated using two distinct methodologies: a fundamental analysis of the plating parameters on a gold planar electrode and their direct impact on the via filling.