A Reverse Selectivity Ceria Slurry for the Damascene Gate Chemical Mechanical Planarization Process

The reverse selectivity of nanosized ceria slurry for the damascene gate chemical mechanical planarization (CMP) process has been investigated. The relationship between the electrokinetic behaviors of abrasive ceria particles and the plasma-enhanced tetraethylorthosilicate (PETEOS), and CVD Si 3 N 4 films in an aqueous medium were observed to determine the reverse selectivity performance in the CMP process. The surface potentials of abrasive and PETEOS/CVD Si 3 N 4 films were found to have different surface charges in certain pH regions and these differences were found to be key parameters in the selective removal performance of damascene gate CMP process. The ceria slurry with polymeric additives showed reverse selectivity with a low PETEOS removal rate and a high CVD Si 3 N 4 film removal rate.