A stress-relief model was developed to explain the phenomenon of spontaneous morphology change observed during room-temperature aging of electrodeposited copper and gold films. The model is based on excess vacancies due to which as-deposited films are initially expanded. These are gradually annihilated at the film surface. Quantitative modeling of vacancy diffusion revealed a well-defined vacancy-depleted zone near the film surface. A tensile stress developed in the near-surface region, the relaxation of which occurred with the formation of surface cracks or islands. The model is general and can be applied to both single-crystal and polycrystalline materials. (c) 2006 The Electrochemical Society.