Polymer Adsorption Effects on Colloidal Stabilities of Ceria Particles and Chemical Mechanical Polishing of Silicone Oxide Films by Ceria Particles

Abstract

Characterization of ceria particles in the presence of poly(vinyl pyrrolidone) (PVP) was performed by the measurements of adsorbed amounts of PVP, average sizes, ζ potentials, and back scattering intensities of the ceria particles as functions of PVP molecular weight and PVP concentration. In particular, the measurements of the hydrodynamic average diameters, ζ potentials, and back scattering intensities of the ceria particles have been carried out for the re-dispersed ceria particles, whose particles were washed by the dispersion medium to remove the free PVP chains and then they were dispersed again in the corresponding dispersion medium after adsorption of PVP on the ceria particles and sedimentation of the ceria particles. PVP adsorption on the ceria surfaces enhanced the stability of ceria particles by the steric stabilization of the thicker adsorbed layer of PVP for the larger molecular weight of PVP. Moreover, the chemical mechanical polishing (CMP) of SiO₂ films deposited on Si wafers has been performed by the ceria slurries without and with PVP. Removal rates of the deposited SiO₂ films were increased with an increase in the adsorbed amount of PVP and their magnitudes were larger than that in the absence of PVP.

Keywords:

• Ceria particles
• chemical mechanical polishing
• poly(vinyl pyrrolidone)
• polymer adsorption
• removal rate
• steric stabilization