Copper was deposited by electron beam evaporation onto both freshly cleaved bare and polyimide-coated (001) NaCl at substrate temperatures of 20°, 100°, 200° and 300°C at rates of 2 and 20,Åsec−1. For all substrate temperatures and deposition rates investigated, the Volmer-Weber mode of film growth was observed for copper both on polyimide and on NaCl. Comparisons of film growth on the two substrates for a constant substrate temperature revealed differences in film thickness at which copper became continuous or formed a completely coalesced film. It was found that copper grown on polyimide formed continuous and completely coalesced films at smaller film thicknesses than on NaCI. However once a completely coalesced film was obtained, grain growth in the copper films proceeded more rapidly on NaC1 substrates than on polyimide substrates.