Monte Carlo simulations of sputter deposition and step coverage of thin films

A combined reactor scale and feature scale Monte Carlo model of sputter dep osition has been developed. The model is based on the statistically average d behavior of a large number of sputtered atoms which undergo gas phase col lisions in the physical vapor deposition (PVD) chamber and surface interact ions within the reactor scale and feature scale domains. The feature scale module is directly coupled with the reactor scale module to predict step co verage at selected locations on the wafer. The simulation results compare f avorably with experimental measurements of cross-wafer uniformity and step coverage of PVD Ti films. Application of the integrated model to assist in optimizing PVD processes for high aspect ratio features and tailoring targe t magnet designs for optimal cross-wafer uniformity is demonstrated. (C) 19 98 Elsevier Science S.A. All rights reserved.