Disparate tendency of stress evolution of thin and thick electroplated Cu films at room temperature

The self-annealing effect of electroplated copper films was investigated by measuring the time dependence of the film stress for different film thicknesses between 1.5μm and 20μm. This recrystallization process results in significant microstructure change and a film-thickness-dependent stress evolution at room temperature. This behavior can be explained by the superposition of grain growth and grain size dependent yielding. Existing models have been used and improved to describe the mechanisms related to stress evolution.