Morphology of electrodeposited Cu on 300 mm PEALD Ru substrates

Abstract

The morphology of thin layers of Cu electrodeposited on 300 mm Ru substrates (deposited by plasma enhanced atomic layer deposition or PEALD) is studied. To reduce the terminal effect, a layer of physical vapor deposited (PVD) Cu is employed beneath the Ru, allowing the characterization of the electrodeposited Cu on PEALD Ru across an entire 300 mm substrate. The morphology of the initially deposited Cu is studied for different current densities and entry biases using topdown scanning electron microscopy (SEM) and post-plating sheet resistance measurements. Electrodeposited Cu particle densities increase with deposition current density, while the particle size appears to change little. Despite the presence of the Cu underlayer, the morphology of the Cu deposited on Ru varies across the wafer, with higher deposited particle densities observed near the wafer edge as compared to the rest of the wafer. © The Electrochemical Society.