Ruthenium Polishing Using Potassium Periodate as the Oxidizer and Silica Abrasives

Silica-based slurries containing potassium periodate at concentration, close to its solubility limit of , polished ruthenium at at an applied pressure of . Moreover, by utilizing the increase in the solubility of achieved by the addition of potassium hydroxide, ruthenium removal rates (RRs) were enhanced to at 9. At this , the toxic does not form, making it potentially attractive for a manufacturing environment. The RRs obtained with silica abrasives are higher than those obtained with alumina abrasives at . A removal mechanism with as the oxidizing agent is proposed based on the formation of several ruthenium oxides, some of which formed residues on the polishing pad below a of . The removal rate selectivities of ruthenium to copper and silicon dioxide are and , respectively.