Chemical Mechanical Polishing of Molybdenum in Potassium Iodate-Based Acidic Slurries

Chemical mechanical polishing (CMP) properties of molybdenum (Mo) by using potassium iodate (KIO3) as the oxidizer and colloidal silica as abrasives have been systematically investigated. It is revealed that the removal rate (RR) of Mo will increase as the concentration of KIO3 and colloidal silica abrasives increase. Both the static etching rate (SER) and the RR of Mo are much higher in the KIO3-based acidic solution than those in the alkaline solution. The lowest SER (around 2.2 nm/ min) and the highest RR (around 90 nm/min) are achieved in the 0.1 M KIO3 solution at pH 2. Comprehensive measurements find that in the KIO3-based acidic solution, the passivation films on the Mo surface are basically MoO3 and Mo2O5 with excellent passivation properties, which are very soft with a small hardness value and can be easily removed through mechanical interaction, especially at pH 2.