Inertial transducer design for manufacturability and performance at Motorola

Manufacturability and performance are key criteria for successful commercial MEMS products. The design of surface micro-machined z-axis capacitive transducers in particular offers challenges to achieving these criteria. These challenges include mechanical layer intrinsic stress and stress gradients (and resulting curvature), package induced deformation, and product standardization. A comparison of a prior transducer design and its present successor illustrates some solutions to these challenges. A design technique is presented that greatly reduces the effect of capacitor plate curvature on device performance. Production data concretely demonstrates the actual improvements achieved.