Effect of Amine Based Chelating Agent and H₂O₂on Cobalt Contact Chemical Mechanical Polishing

Abstract

When the technology node goes down to 7nm and below, cobalt (Co) has been identified as the promising candidate for the inter-connect/contact material. In this paper, we investigated the effect of amine based chelating agent and H2O2 on cobalt contact chemical mechanical polishing (CMP) in colloidal silica based slurry at pH 8. It revealed that the combination of H2O2 and FA/O II can significantly improve the cobalt removal rate (RR) by an order of magnitude. The electrochemical measurements, X-ray photoelectron spectroscopy (XPS), UV-visible (UV-vis) spectroscopy experiments were applied to explore the removal machanism of Co film. The high removal rate of Co may be due to the formation of the water-soluble Co(III)-FA/O II complex. And relatively low dissolution (≤1 nm/min) and good surface quality was achieved by adding a novel corrosion inhibitor.