Coupling of equipment simulation and feature-scale profile simulation for dry-etching of polysilicon gate lines

Abstract

We demonstrate the coupling of plasma reactor equipment simulation and feature-scale profile simulation for dry etching of silicon in a chlorine plasma. Equipment simulation delivers fluxes of ions and neutrals, as well as the angular characteristics of the ions. These quantities are fed into a feature-scale simulator based on a Monte Carlo approach for determining relevant quantities on the feature surface, i.e. the concentration of adsorbed neutrals and the number of removed silicon atoms due to chemical sputtering. Using the coupled simulation system, we are able to study the influence of equipment parameters on the resulting etching profiles. As an example, we show the etching of polysilicon for gate formation and determine profile variations according to different positions on the wafer and according to varying bias applied to the substrate in the etching reactor.