Frictional and removal rate studies of silicon dioxide and silicon nitride CMP using novel cerium dioxide abrasive slurries

Novel slurries containing cerium dioxide particles as the abrasives were used for silicon dioxide and silicon nitride CMP in this study. Real-time frictional force was measured during polishing. Slurries with varying ceria abrasive concentrations achieved different friction forces during the silicon dioxide and silicon nitride polishing. The effects of the ceria abrasive concentration on the silicon dioxide and silicon nitride removal rates were also investigated. The silicon dioxide removal rates exhibited non-Prestonian behavior, which was attributed to the additives used in the slurries. Being specially formulated for shallow trench isolation (STI) applications, these novel slurries achieved high oxide-to-nitride removal rate selectivities.