Conditions for which superconformal filling of vias can be expected are predicted using the curvature enhanced accelerator coverage mechanism to model the effect of accelerator accumulation and area change on local copper deposition rate. Superconformal filling of vias is predicted to occur over a more limited range of electrodeposition conditions than in trenches of similar aspect ratio with significant implications for dual damascene processing. Parameters for the model describing both the accumulation of accelerator on the copper/electrolyte interface and the impact of the accumulated accelerator on the local deposition rate come from voltammetry experiments on planar electrodes. An idealized geometry permits reduction of the 3D filling problem to solution of a system of coupled first-order, nonlinear ordinary differential equations. (C) 2002 The Electrochemical Society.