Vacuum based wafer level encapsulation (WLE) of MEMS using physical vapor deposition (PVD)

In this paper, we demonstrate wafer level encapsulation of MEMS using physical vapor deposition of aluminum (Al). A cavity area, which simulates the area of a MEMS device, is fully encapsulated by dual layer of amorphous silicon and Al. The encapsulation process takes place in the PVD chamber, thus the vacuum level in the sealed cavity is assumed to be high. The proposed processes are entirely CMOS compatible and readily deployed into any standard CMOS foundry and semiconductor wafer fabrication.