Polymer Adsorption Effects on Stabilities and Chemical Mechanical Polishing Properties of Ceria Particles

Characterization of ceria particles in the presence of poly(vinyl pyrrolidone) (PVP) was performed by the measurements of adsorbed amounts of PVP, average sizes, and back scattering intensities of the ceria particles as functions of PVP molecular weight and PVP concentration. Adsorption of PVP on the ceria particles enhanced the stability of ceria particles due to steric stabilization of the thick adsorbed layer of PVP. Moreover, SiO2 and Si3N4 films deposited on Si wafers were polished by the ceria particles in the presence of PVP in order to understand the effect of PVP adsorption on chemical mechanical polishing (CMP) technique, together with ceria particles without PVP and re-dispersed ceria particles adsorbed by PVP in water (re-dispersed ceria). Removal rates of the deposited SiO2 and Si3N4 films were decreased with an increase in the concentration of free PVP chains in the dispersion media, while the removal rates by the re-dispersed ceria were the same as those by the ceria particles in the absence of PVP.