Development of RIE Processes for the Etching of Single Crystal Silicon, Silicon Dioxide

Etching of micro-structures in a single crystal Si, SiO2 has been obtained using reactive ion etching with SF6/O2 and CF4/O2 gas mixtures respectively. The variation in etch rate of Si and SiO2 has been observed by varying gas composition, reactants flow rate, pressure and duration of plasma process. The reactive ion etching is normally carried out using RF (Radio frequency) plasma. In the present work, we have utilized LF (Low frequency) for the RIE (Reactive ion etching) processes. High etch rate of Si of 0.344m/min has been achieved with SF6/O2 plasma and etch rates of SiO2 are 0.0316m/min achieved using CF4/O2 at 40 KHz. The results show that O2 concentration and pressure has strong effect on etch rates. Also the variation in etch rate is influenced by variation in power. The etching processes developed in this work are aimed for surface micro-machining of silicon for the fabrication of MEMS (micro electro mechanical system) devices.