Abstract
A simple method of protecting film bulk acoustic resonator (FBAR) filters by wafer-level packaging is proposed. This method employs a reliable silicon microcap structure to encapsulate FBAR filters. Since only conventional processes and facilities were required to accomplish this work, it is a cost-effective way to package FBAR filters. The fabrication process consists of three steps: cavity etching, wafer bonding and wafer singulation. In this study, the design and fabrication processes are described in detail. Moreover, a filter designed for personal communication systems (PCS) transmitter band is measured to demonstrate the performance variation after the microcap process. The fabrication results and measurement results have ensured the effectiveness of this process. © 2005 IOP Publishing Ltd.