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

A combined reactor scale and feature scale Monte Carlo model of sputter deposition has been developed. The model is based on the statistically averaged behavior of a large number of sputtered atoms which undergo gas phase collisions in the physical vapor deposition (PVD) chamber and surface interactions within the reactor scale and feature scale domains. The feature scale module is directly coupled with the reactor scale module to predict step coverage at selected locations on the wafer. The simulation results compare favorably 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 target magnet designs for optimal cross-wafer uniformity is demonstrated. (C) 1998 Elsevier Science S.A. All rights reserved.