A fast and CMP-free TSV process based on wafer-level liquid-metal injection for MEMS packaging

In this paper, we proposed and demonstrated a MEMS packaging process that for the first time integrates a specifically developed TSV technology. In the proposed packaging process, after capping, alloy TSVs were fabricated by a wafer-level liquid-metal injection method that is based on combinative effect of liquid-bridge rupture and capillary action. Taking advantage of liquid-metal filling, the TSV filling can be finished in few minutes. Furthermore, the specific TSV process is capable to achieve flat via-surface, a feature that can dismiss the Chemical-Mechanical Polishing (CMP) process that is necessary after conventional plating-filling.