Green chemical mechanical polishing of copper with 2,5-dihydroxy-1,4-dithianeas as the inhibitor: Experimental and theoretical studies

Abstract

It is a great challenge to develop green chemical mechanical polishing (CMP) technique owing to the limited inhibitory performance of green inhibitors. In this study, 2,5-dihydroxy-1,4-dithiane (DHD) was found and utilized as a superior inhibitor in CMP slurry, which realized nanometer-scale smoothness for copper surface. The strong inhibition effect of DHD, in both static and dynamic situations, was demonstrated by microscopic observations and electrochemical characterizations. The effectiveness of DHD was achieved mainly through its chemisorption onto copper surface, determined by Langmuir adsorption isotherm. X-ray photoelectron spectroscopy and density-functional-theory calculations proved that the chemisorption occurred between the S atom of DHD and Cu. Overall, DHD as an efficient and eco-friendly inhibitor with low-cost exhibits immense potential for applications in chip fabrication, particularly at a low technology node.