In this paper, we study the influence of additives in the filling process of via holes for LSI Cu interconnections by using the kinetic Monte Carlo method. As a model for electroplating, we extended the Solid‐by‐Solid model for crystal growth to include additives which inhibit the adsorption of new atoms. This enables us to control the local surface growth rate to find out the optimal deposition condition for void‐free filling. The distribution of additives on the surface and their influence on the surface and void structures are carefully examined. © 2004 American Institute of Physics