Effect of Electric Potential and Mechanical Force on Copper Electro-Chemical Mechanical Planarization

Abstract

In this study, the dependence of Cu electrochemical mechanical planarization (ECMP) rate on electric potential and mechanical force in electrolyte is investigated using potentiodynamic analysis, electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS). In chemical etching, CMP, electropolishing, and ECMP processes, the Cu removal rate is mainly affected by the interplay between electric potential and mechanical force. An equivalent circuit is built by fitting the EIS results to explain the behavior of Cu dissolution and Cu passive film. The Cu dissolution rate increased with decreasing charge-transfer time-delay. The resistance of the Cu passive film (R-p) is proportional to the intensity ratio of Cu2O/[Cu(OH)(2) + CuO]. (C) 2012 The Japan Society of Applied Physics