P3I-3 Wafer Level Chip Size Packaging of SAW Devices Using Low Temperature Sacrifice Process

In this paper, we report a basic study on wafer level chip size packaging (WL-CSP) process of SAW devices using low temperature sacrifice process. We used the dry film photoresist as sacrifice layer because it has advantage such as low treating temperature (<120 degree), easily coating on the surface of wafer and easily to removal by organic solution. We proposed several processes using dry film photoresist for different purpose. We investigated various processing conditions and successfully fabricated a cavity with small size as active area of the SAW device. The experimental results confirmed feasibility of the dry film photoresist used in WL-CSP technology of SAW device.