Generalized Thermal Design Model for Comb-Capacitor MEMS Devices Fabricated by Bonding-DRIE Process: A Preliminary Framework

Abstract

Bonding-deep reaction ion etching (DRIE) is a standard microelectromechanical system (MEMS) fabrication technique, especially for widely-applied comb-capacitor microdevices. Being the key structure in the comb-capacitor devices, long and narrow suspended beams suffer a serious heat transfer problem during their releasing in the fabrication because of the high heat flux input and the large thermal resistance. Temperature increment of the micro beam in the DRIE releasing, especially in the unavoidable over etching stage, may cause serious problem, even lead to a failed etch. This work introduced a generalized thermal design model to estimate the possible temperature increment of microstructure in DRIE. The preliminary results indicated that this model was able to capture the basic trend of temperature variation with the geometrical parameters in a comb-capacitor MEMS device during its DRIE releasing.