Single-molecule spectroscopic analysis of adsorption phenomena on colloidal silica abrasives used in chemical-mechanical planarization slurries

Advances in the use of a single-molecule spectroscopic method, fluorescence correlation spectroscopy (FCS), for the determination of the particle size distribution (PSD) of fine dispersions of colloidal silica and ceria abrasive particles employed in CMP slurries are described. The Maximum Entropy Method (MEM) is shown to be an effective approach for PSD analysis using FCS data for fluorescently dyed abrasive particles. FCS also provides an analysis of absorption phenomena on CMP abrasive particles using a fluorescent dye for the quantitative determination of adsorption isotherms. Extension of the FCS technique to the characterization of the adsorption of CMP slurry additive to colloidal silica and ceria abrasives is proposed.