Effect of Potassium Oleate as Inhibitor on Copper Chemical Mechanical Polishing

The effect of potassium oleate (PO, C₁₈H₃₃KO₂) in a glycine-based weakly alkaline slurry on copper chemical mechanical polishing (CMP) process was discussed. The corrosion inhibitor in the slurry could balance the over etching to realize the global planarization of the copper layers. The experimental results verified PO was indeed effective in inhibiting copper removal rate. The corrosion and passivation mechanism were also discussed. SEM and XPS test results confirmed that PO can adsorb on the copper surface to form a passivation film.