Numerical modeling and experimental verification of copper electrodeposition for through silicon via (TSV) with additives

Since voids and seams are easily formed during the process of filling TSVs with high aspect ratio, good methods that can achieve the superfilling of TSVs are eagerly needed. This paper presents the numerical modeling of TSV filling concerning the influence of three additives (accelerator, suppressor and leveler). By changing the additives' doses and current density, the following three different simulation results were obtained: the pinch-off effect, seam-inside filling model and “V” shaped filling model. The corresponding distributions of the current density along the cathode surface were analyzed to investigate the filling mechanism. Moreover, TSV filling experiments in the presence of additives were also conducted to validate the proposed numerical model. The simulation results matched well with the experimental results. TSVs with a diameter of 20 μm and depth of 200 μm were fully filled in the appropriate conditions.