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Effects of Ce3+ on removal rate of ceria slurries in chemical mechanical polishing for SiO2

Ceria abrasives which are made with wet chemical precipitation method are expected to reduce defects on SiO2 films, but improvement of removal rate is required. When picolinic acid or additive A was added in the ceria slurries, the removal rate improved to the same level as conventional calcined ceria. Many researches about mechanisms of removal rate enhancement of ceria slurries have been conducted and there are still some hypotheses of the mechanisms. In this research, we focused on effects of Ce3+ atoms in the ceria slurries on the removal rate. The results, using UV-visible spectroscopy and X-ray photoelectron spectroscopy (XPS), indicate that the Ce3+ atoms in the slurries can facilitate the reaction between ceria and SiO2 film.