UMEMS: A Robust Technology Platform For Quality Automotive Inertial Sensor Manufacturing

Abstract

A new MEMS technology platform, UMEMS, has been developed and released for automotive inertial sensors manufacturing. Several features, including 1) single crystal Silicon MEMS proof mass, 2) polysilicon Through-Si-Via (TSV), 3) AlGe eutectic wafer bonding, and 4) metal redistribution layer (RDL) routing, have been employed in UMEMS to improve reproducibility, reliability, flexibility and reduce cost. The single crystal Silicon proof mass has minimal internal stress. AlGe bonding serves the dual function of 1) electrically connecting TSV in the cap wafer and the silicon electrodes/interconnects in the device wafer, and 2) hermetically sealing the MEMS cavity from external environment. The TSV and RDL allow great design flexibility and re-use for large automotive product families. We also introduced a quality methodology called Above-and-Beyond ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$A$</tex> aB) in the development and product introduction, which enables UMEMS to be released in volume manufacturing with sub-lppm defectivity at early phase of production.