Tailoring Copper Island Density for Copper Plating on a RuTa Substrate

The electrochemical nucleation and growth of copper on a ruthenium-tantalum (RuTa) alloy has been studied using galvanostatic methods. The experimental results show that the island density is highly dependent on the bath composition and deposition parameters. High island density was achieved with higher applied current, addition of suppressor and low copper concentration in the plating bath.