Origin of high oxide to nitride polishing selectivity of ceria-based slurry in the presence of picolinic acid**Project supported by the Center for Advanced Materials Processing (CAMP) at Clarkson University, the National Integrate Circuit Research Program of China (Grant No. 2009ZX02023-3), the National Basic Research Program of China (GrantNos. 2007CB935400, 2010CB934300 and 2006CB302700), the National High Technology Development Program of China

Abstract

We report on the investigation of the origin of high oxide to nitride polishing selectivity of ceria-based slurry in the presence of picolinic acid. The oxide to nitride removal selectivity of the ceria slurry with picolinic acid is as high as 76.6 in the chemical mechanical polishing. By using zeta potential analyzer, particle size analyzer, horizon profilometer, thermogravimetric analysis and Fourier transform infrared spectroscopy, the pre- and the post-polished wafer surfaces as well as the pre- and the post-used ceria-based slurries are compared. Possible mechanism of high oxide to nitride selectivity with using ceria-based slurry with picolinic acid is discussed.