Shape evolution during electrodeposition of copper in microtrenches was studied numerically by a model which incorporates adaptive meshing capabilities. Filling of trenches with copper without creating a void was related to plating additives in solution. The shape-change behavior of this system resulting from variation of the feature's aspect ratio, bulk composition, and level of additive components was investigated. The operating window of bath conditions for void-free electrodeposition was studied in the range of 0.25 x 10(-4) to 10(-4) M bulk concentration of additive in a 0.25 M CuSO4 + 0.2 M H2SO4 plating solution and for aspect ratios (depth:width) from 0.5 to 4. The mathematical model includes fluid flow, transport by diffusion, migration and convection, multiple species, and reactions in complex geometries. (C) 2000 The Electrochemical Society. All rights reserved.