Investigation of the Galvanic Effect between RuN Barriers and Cu Seed Layers

Abstract

In this study, we investigated the galvanic effect between the Cu metals and ruthenium nitride (RuNx) films that were deposited at various nitrogen (N-2) gas flow rates in chemical mechanical polishing slurries. It was found that the galvanic corrosion of the RuNx films was inhibited with increasing N-2 gas flow ratio, whereas the galvanic corrosion of the Cu seed layers was enhanced. Electrochemical impedance spectroscopy showed that the galvanic corrosion resistance of RuNx increased and that of the ruthenium oxide layer decreased as N-2 flow ratio increased. This was because the increase in the N content in the RuNx films inhibited the corrosion and oxidation of the Ru metals. (C) 2011 The Japan Society of Applied Physics