The Triboelectrochemical Properties and Mechanism of Ruthenium ECMP

Electrochemical mechanical polishing (ECMP) has emerged as a promising alternative to conventional chemical mechanical polishing (CMP), particularly for addressing challenges in planarizing ruthenium (Ru)—a critical barrier-layer material in advanced copper interconnects. This study systematically investigates the triboelectrochemical behavior and underlying mechanisms of ruthenium during ECMP, with a focus on the effects of mechanical power (induced by load and rotational speed) and applied potential. Through open-circuit potential measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS), we demonstrate that mechanical energy input significantly enhances electrochemical reactions, with rotational speed exerting a more pronounced influence than applied load. Notably, the corrosion potential increases with load at constant speed, while the friction coefficient rises as rotational speed decreases. EIS analyses further reveal that higher rotational speeds promote the formation and growth of a thicker passive oxide film on ruthenium surfaces. These insights provide a theoretical foundation for optimizing ECMP processes toward high-efficiency, high-selectivity, and low-damage planarization of Ru-based interconnect structures.