Copper pulse plating on Ru/TaSiN barrier

The properties of pulse plated copper electrodeposits (1 mum) on ruthenium (5nm)/TaSiN (5nm) diffusion barrier with current density ranging from 2 to 20 A/dm² are studied. The resistivity of the Cu film is about 2.7muOmegamiddotcm. A (111) preferential orientation is found in almost all cases, which would be good to electromigration performance. Grain size of Cu electrodeposits reduces with increasing current density. Different growth mode is found in low and high current densities. The surface morphology of the copper electrodeposits is very rough at low current densities, due to the bigger grain size.