Prediction of Removal Rates in Chemical–Mechanical Polishing (CMP) Using Tribocorrosion Modeling

Abstract

The influence of electrochemical parameters, open circuit potential, and passivation kinetics, on the removal rates of tungsten in chemical–mechanical polishing (CMP) was investigated in the presented study. Removal rates were measured on a CMP machine, while electrochemical test were performed separately, both using technical CMP slurries. Electrochemical parameters are shown to have a strong influence on tungsten removal rate in CMP. Tungsten removal rate increases with the open circuit potential (electrode potential) and with passivation charge density. A model of Kaufman mechanism previously developed for sliding tribocorrosion of tungsten was adapted to the CMP conditions. This model describes removal rate in terms of both mechanical and electrochemical parameters and was found to effectively rationalize experimental results obtained in different CMP solutions according to their electrochemical properties.