IC-compatible processing of inertial sensors using SF6-O2 cryogenic plasma process

An IC-technology compatible process lor high aspect ratio trench based microinertial devices was developed, using cryogenic SF₆-O₂ plasma etching as a single postprocessing step. Furthermore it involves either silicon to silicon dry etch BCB bonding, Si wafer thinning and a method for front-to-backside alignment using ASML PAS5000/50 waferstepper. The wafer thinning is performed using TMAH wet etching bringing the advantage of possible batch fabrication. The process flow includes a single resist mask for both the Al etching and the high aspect ratio plasma etching of the mechanical structure.