Effect of passivation on frit glass bonding method for wafer level hermetic sealing on MEMS devices

摘要

A wafer level hermetic package has been developed for micro-electronics mechanical system (MEMS) applications by wafer to wafer bonding method. A cap wafer, glass or silicon wafers was used on top of the MEMS device to protect the MEMS device during the assembly process. Frit glass paste is patterned on the cap wafer and is used as the intermediate layer for wafer bonding. The adhesion and reliability of frit glass bonding have been studied with different passivation materials, silicon oxide and silicon nitride. Verification of bonding quality was done by shear test, water test for the gross leak, fine leak test, and an X-ray technique for voids inspection. Compatibility of the frit glass on oxide passivation can be improved with an additional annealing step before frit glass deposition.