A high aspect ratio MEMS process with surface micromachined polysilicon for high accuracy inertial sensing

A unique process is described that has the advantages of high aspect ratio, deep reactive ion etched, single crystal silicon with the diversity of polysilicon surface micromachining to enable advances in capacitive inertial sensing. This process has been designed to incorporate a fully released via between the two structural layers which considerably increases the design capabilities, providing a means for improved package stress isolation and area efficiency. A high accuracy low-g XY accelerometer for the automotive electronic stability control market is presented using this technology.