A combined simulator linking gas flux data from a plasma reactor (experimental or simulated) to the feature profile evolution during etching/deposition processes is described. This combined simulator results from the coupling of surface etch, local flux calculation, and profile evolution modules. It is a modular tool, in the sense that different phenomena, surface models, and structures can be incorporated. In this work the combined simulator is applied in two processes: (a) in SiO2 feature etching to simulate reactive ion etching (RIE) lag and inverse RIE lag and (b) in etching of high aspect ratio Si trenches using the Bosch process. The profile evolution algorithm of the combined simulator, namely, the level set method, is applied to a process where etching and deposition occur, and tracking of two materials (Si and polymer formed during the Bosch deposition step) is needed. (C) 2004 American Vacuum Society.