The fundamental mechanism of room-temperature grain growth during self-annealing in electroplated Cu films has been an issue of great interest. We have investigated the microstructure evolutions in a variety of electroplated Cu films prepared with different plating rates and their correlation with the crystalline defects in the as-deposited films. The recrystallization process in all Cu films is greatly accelerated as the plating current density is increased, while the grains are initially small and about the same in sizes (similar to0.1 mum) in as-deposited films regardless of the plating current density. Using plan-view transmission electron microscopy imaging, the existence of a high density of dislocation loops is demonstrated successfully in the pre-recrystallization grains of as-deposited Cu films. The density of the dislocation loops is higher for the film deposited at higher plating current density (higher plating rate). These observations lead us to propose that the change of self-annealing rate with the plating rate is related to the dislocation loop density in the film before the self-annealing starts. Plating with high deposition rate produces a large amount of intrinsic stress induced by the formation of dislocation loops and increases the total energy stored in the Cu film, which will act as the major driving force for self-annealing process. Kinetic calculations including this effect in the driving force for the self-annealing process give a good correspondence to the experimental observations. (C) 2004 American Vacuum Society.