SAW Cavity Sealing using Dielectric film in Wafer-level packaging

A SAW filter cavity sealing method using Dielectric film was demonstrated in wafer level packaging process flow in this work. This cavity sealing test vehicle is based on various cavity sizes ranges from 300um up to 1800um wide. The demonstration was done by sealing the cavity structure with dielectric film. The sealed cavity then covered with PVD layer and molded by epoxy mold compound. The cavity structure tested to withstands the pressures of PVD and molding. Various supported cavity sealing was studied such as with fin structure support, pillar support and with no support structure inside the sealed cavity. All three structures are found to withstand the pressures of PVD and molding processes.