Enhancement of silicon etching rate in XeF 2 ambient in the presence of activated polymer

Abstract

Enhancement of silicon etching rate in XeF 2 ambient is considered by a proposed model, which includes processes of adsorption, activation, chemical reactions, relaxation, desorption, and sputtering. The enhancement of silicon etching rate is explained by considering hydrocarbon species present in the vacuum chamber and assuming that activated sites (radicals) in the polymer film enhance the etching rate. The composition of the adsorbed layer during silicon etching in XeF 2 ambient is calculated. It is found that activated polymer intensifies reaction of XeF 2 molecules with Si atoms on the surface and causes the variation of the etching rate. Using the obtained theoretical results the difference in kinetics of the etching rates of first and subsequent runs is explained.