(Invited) Surface Adsorption of CMP Slurry Additives on Abrasive Particles

Fluorescence correlation spectroscopy (FCS) is used to study additive-abrasive particle interactions in chemical-mechanical planarization (CMP) slurries. FCS provides quantitative determinations of the binding between additives and abrasive particles by characterizing the competitive adsorption of the additive and a fluorescent probe molecule, Alexa fluor 546 (A546) at the surface of a silica abrasive particle. Analysis of the adsorption of benzotriazole (BTA) on colloidal silica confirms the displacement of A546 by added BTA. However, glycine enhances the adsorption of A546 by colloidal silica. FCS is also shown to be a sensitive technique for detecting differences in the surface chemistry between different types of colloidal silica abrasive particles used in CMP processes.