Published online by Cambridge University Press: 17 March 2011
We have developed platinum (Pt) deposition and chlorine-based Reactive IonEtch (RIE) processes that are needed to deposit, pattern and embedelectrodes deep within a MEMS process flow. Various combinations ofchlorinebased gases were tested to find the optimum gas mixture for RIE. A1: 0.4 mixture ratio of pure chlorine to argon and 100-150 Watts of RFmicrowave power were found to be optimum conditions for the RIE of platinummetal. The addition of argon gas to chlorine was found to contribute to theanisotropic etching of platinum, obtaining vertical shaped sidewallpatterns. A simple model of the platinum etching mechanism is proposed.Following the plasma enhanced formation of platinum and chlorine ions,volatile products of platinum chlorides were formed and driven away atelevated temperature. As a demonstration of our RIE process, micron-sizedplatinum patterns with vertical sidewalls were fabricated. Etch chemistrywas investigated using ToF SIMS analysis. This etch technique will be usefulto device developers intending to use the unique properties of platinummetal as an electrode that is deeply embedded within a MEMS processflow.