Process compensated micromechanical resonators

Abstract

Manufacturability and yield are the major challenges prior to adoption of micromechanical resonators as frequency references. In this paper, a design for manufacturability (DFM) technique to achieve absolute frequency accuracy is presented. Non-idealities of a deep reactive ion etching process are examined and determined to be random. The variations in resonator geometry are assumed to be locally systematic and are represented as a process bias. The effect of process bias on resonator center frequency is modeled and the procedure for optimizing for zero sensitivity is explained. Process bias on a 10 MHz optimized design was replicated with electron-beam lithography and supporting data demonstrating DFM is reported.