Preparing method of silica slurry for wafer polishing

Abstract

Disclosed herein is a method of preparing silica slurry for wafer polishing. This method includes pre-treating relatively inexpensive and commercially available fumed or colloidal silica particles as a seed by a settling, a crushing using a ball mill and a paint shaker, and a sonication to produce an aqueous dispersion of the silica particles. The pre-treated silica particles are then combined with tetraethylorothosilicate as a precursor, an alcohol solvent and a base, and grown to a desired size by hydrolysis and polycondensation of the precursor, tetraethylorothosilicate. Then, the alcohol solvent, in which the silica particles are grown, are displaced with water by a vacuum distillation. The resulting aqueous dispersion of the grown silica dispersion is hydrothermally treated in an autoclave. Thus, this method allows the economical preparation of the spherical silica particles having a highly uniform size and a very high purity.