Effects of Ceria Abrasives on the Chemical Mechanical Polishing of Molybdenum Film with Alkaline H₂O₂ Slurries

The impact of ceria abrasives on the chemical mechanical polishing (CMP) of molybdenum (Mo) films was examined in alkaline slurries utilizing H 2 O 2 as an oxidizer and ceria abrasives. The static etching rate (SER) decreased after the addition of ceria abrasives to the alkaline H 2 O 2 -based slurry, while the removal rate (RR) increased except for that of the slurry at pH 9. At pH 9, following the etching of the Mo film in an H 2 O 2 solution with ceria, the surface became coated with MoO 3 and Ce 2 Mo 4 O 15 species. These species originated from the interaction between ceria, H 2 O 2 , and molybdic acid. The Ce 2 Mo 4 O 15 particles envelop the MoO 3 surface, thereby preventing the etching of loose MoO 3 and hindering further oxidation of Mo to MoO 3 . This process effectively reduces the RR of Mo. Utilizing ceria slurries at appropriate pH values facilitates achieving a smooth surface with a reasonable RR.