A SAW filter integrated on a silicon passive substrate used for system in package

A packaging method for dies containing an electro-mechanical component on a silicon substrate with a polymer seal ring is described in this paper. A Surface Acoustic Wave (SAW) filter, which is a kind of Micro Electro-Mechanical System (MEMS), is used as a capping substrate. Two different polymers are tested, Benzocyclobutene (BCB) and SU-8. The polymer and the assembly processes are described. The package has been characterized mechanically and the influence of the package on the electrical operation of the filter has been evaluated. A finite element thermo-mechanical analysis has been performed to simulate and understand the behaviour of this heterogeneous flip-chip package. This package enables to decrease the size of the assembly around 50% in term of thickness and footprint area without any electrical degradation compared to a stand-alone component.