Etch Selectivity of Silicon Dioxide over Titanium Silicide Using CF 4 / H 2 Reactive Ion Etching

Selective reactive ion etching of over in a flexible diode reactor has been studied using and . Different flow rates, and quartz and Teflon electrode materials, were evaluated and shown to have a profound effect on the etch selectivity. Addition of greatly increases the selectivity without markedly affecting the oxide etch rate. Teflon was shown to be the more effective electrode material over quartz for high oxide etch rates and selectivity with the addition of to the plasma. Increasing the total flow rate increased the etch selectivity in most cases, and we have achieved etch rate ratios greater than 40:1. Using x‐ray photoemission spectroscopy, a surface region was observed under all conditions. The lowering of the etch rate correlates to the increase in fluorocarbon film and appears to be primarily due to the selective formation of the film on and not on .