Exploration on functional groups of complexing agents during chemical mechanical polishing for Co interconnects

This study systematically investigated the effects of complexing agents with different functional groups on the material removal rates (MRRs) of cobalt (Co) and titanium (Ti) during chemical mechanical polishing (CMP) of Co interconnects and Ti barrier structures. The results indicated that Co removal is predominantly governed by corrosion removal and corrosion-induced wear, which are primarily driven by chemical corrosion mechanisms, with rapid removal facilitated by mechanical action. Complexing agents containing ─NH₂ functional groups significantly enhanced the removal rate; in contrast, Ti removal primarily relies on mechanical removal and exhibits lower sensitivity to chemical corrosion. Based on the experimental results, a database of functional groups for complexing agents was constructed and validated, demonstrating that adjusting the types and concentrations of these functional groups can effectively achieve selective control over material removal. This finding provides a scientific basis for further optimizing the composition and performance of CMP slurries.