The Effect of Grain Boundary Characteristics on Microstructure and Stress Void Evolution in Electroplated and Sputtered Cu Films

摘要

The evolution of stress-induced damage in copper films during annealing was investigated. Various Cu films were fabricated using sputtering and electroplating with and without additives. After annealing at 435°C, the differences in the morphology of stress-induced surface damage were observed. Some films showed shallow grain boundary wedges along the grain boundaries while in others deep voids at grain boundary triple junction were observed. It was found that the grain size and film thickness as well as fraction of the high energy grain boundaries determines these morphological differences. A model based on relative contribution of the grain boundary and the surface diffusion was suggested.