A 3-D wafer level hermetical packaging for MEMS

In this paper, a 3D wafer-level hermetical packaging solution for micro-electromechanical-system (MEMS) is presented. The MEMS wafer is sandwiched between a top glass wafer and a bottom Si substrate wafer. With the assistance of a gold intermediate layer, the bottom Si wafer is hermetically sealed to the MEMS wafer with 3D electric feed-through connecting the metal pads on MEMS wafer with solder balls or bonding pads on bottom wafer for flip chip process. The bond strength is higher than 5 MPa.