A new approach to aspect ratio independent etching

Abstract

An influence of physisorbed states at the surface on scaling of etch rates with aspect ratio, feature width, and temperature is investigated. A non-linear adsorption model for the inhibitor particles is applied for description of plasma etching of trenches in silicon. Etch rates are aspect ratio independent at definite temperatures and flux ratios: ion/(passivating neutrals) and (active neutrals)/(passivating neutrals) ratios which affect this process and can be varied independently. Lowering of the temperature may be necessary for obtaining aspect ratio independent etching with a small decrease of the etch rate.