Effect of Organic Additives on Ceria Slurry in Shallow Trench Isolation Chemical Mechanical Planarization

Abstract

An increase in the removal selectivity between silicon oxide and silicon nitride was attempted by adding organic additives to a ceria slurry for the application of shallow trench isolation (STI) chemical mechanical planarization (CMP). The protection behavior of poly(acrylic acid) (PAA) and the acceleration behavior of RE-610 in a ceria slurry were studied. PAA served as a protector of the silicon nitride due to the change in zeta potential. RE-610 worked as a hydration accelerator of the silicon oxide. When the two additives were added to the ceria slurry, the removal selectivity increased to 31 : 1. Moreover, PAA improved the stability of the ceria slurry.