Real dimensional simulation of anisotropic etching of silicon in CF 4+O 2 plasma

Abstract

The reactive ion etching (RIE) of silicon in CF 4+O 2 plasma is considered. The profiles of etched grooves are calculated as a function of mask dimensions, fluxes of chemically active and non-active plasma components and parameters of ion bombardment. To achieve this goal the chemical composition of CF 4+O 2 plasma is calculated and the one-dimensional plasmochemical etching (PCE) of Si in this plasma is considered. The values of phenomenological constants are found by extrapolation from experimental results. Using values of phenomenological constants, found by analysis of chemical composition of plasma and one-dimensional etching, the etched groove profiles at real dimensions are calculated. Special attention is given to the etching anisotropy and lateral etching. The influence of oxygen addition to fluorocarbon plasma on etched groove profile is considered. The conditions under which anisotropic etching prevails are found.