Simulation of silicon dry etching through a mask in low pressure fluorine-based plasma

Abstract

The ion beam assisted etching of silicon through a mask in a low pressure fluorocarbon plasma is considered. The two-dimensional profiles of etched grooves are calculated using a proposed model involving a function of mask size, the fluxes of incident chemically active and non-active species from the plasma and bombarding ions. The model also includes the processes of adsorption, heterogeneous reactions, desorption, physical sputtering, activation of surface atoms and stochastic mixing between monolayers. Special attention is given to the etching anisotropy, lateral etching and elemental composition at the surface of a groove. It is shown, that formation of an inhibiting film on the sidewall of groove increases the etching anisotropy, however, the process of stochastic mixing leads to the formation of the altered layer in the near surface region. The thickness of altered layer and elemental composition at different surface regions of etched groove is considered.