Surface modification of nanocolloidal silica for use as polishing abrasive particles

A new type of abrasive particle for polishing the dielectric layer on silicon wafers has been synthesized by modifying colloidal silica with cerium ions. Cerium ions in active silicic acid were titrated into a basic solution at 100 °C to modify the surface of the colloidal silica. The new abrasive particles are easily suspended in an aqueous medium. The removal rate of the dielectric film was higher when the modified colloidal silica was used for polishing than when the original colloidal silica was used as a polishing slurry. The effects of cerium-ion concentration [Ce4+] and seed concentration on the mean particle size of modified colloidal silica and the polishing performance of colloidal silica were investigated in the present study.