Chemical Mechanical Polishing of Ruthenium Barrier Layers for Advanced Integrated Circuits

Ruthenium (Ru) is gaining traction as an ultrathin barrier/liner for advanced Copper (Cu) interconnects because it couples low resistivity with excellent thermal stability and robust Cu diffusion blocking ability. However, the complex surface chemistry and heterogeneous oxide formation of ruthenium make its chemical mechanical polishing (CMP) inherently challenging, often forcing narrow trade‐offs among removal rate, selectivity to Cu and dielectrics, and defectivity caused by tribo‐electrochemical and galvanic corrosion. Herein, this review summarizes the materials rationale for Ru integration, distills prevailing oxidation–dissolution–abrasion mechanisms, and compares representative slurry designs (oxidants, complexing agents, inhibitors, surfactants, and abrasives) that enable controllable Ru planarization. We further discuss dominant defect modes and mitigation strategies, including corrosion suppression, roughness regulation, and selectivity engineering, and we highlight emerging opportunities in catalytic/advanced oxidation, environmentally benign formulations, post‐CMP cleaning, and data‐enabled process control. These perspectives are intended to guide rational slurry design and process integration for reliable Ru CMP at future technology nodes.