SIMULATION OF SILICON DRY-ETCHING THROUGH A MASK IN LOW-PRESSURE FLUORINE-BASED PLASMA

The ion beam assisted etching of silicon through a mask in a low press ure fluorocarbon plasma is considered. The two-dimensional profiles of etched grooves are calculated using a proposed model involving, a fun ction of mask size, the fluxes of incident chemically active and non-a ctive species from the plasma and bombarding ions. The model also incl udes the processes of adsorption, heterogeneous reactions, desorption, physical sputtering, activation of surface atoms and stochastic mixin g between monolayers. Special attention is given to the etching anisot ropy, lateral etching and elemental composition at the surface of a gr oove. It is shown, that formation of an inhibiting film on the sidewal l of groove increases the etching anisotropy, however, the process of stochastic mixing leads to the formation of the altered layer in the n ear surface region. The thickness of altered layer and elemental compo sition at different surface regions of etched groove is considered. Co pyright (C) 1996 Elsevier Science Ltd