A laser light scattering technique was used for the identification of defects on silicon dioxide (SiO2) wafers polished with a tungsten CMP slurry. Defects were then classified as scratches and particles using scanning electron microscopy (SEM). The effects of the incident beam illumination and scattering geometry on the defect detection are examined. Appropriate experimental conditions for selective detection of scratches and particles are discussed in conjunction with the estimated defect count and fractional ratio for specific defect types and sizes. The findings are qualitatively consistent with predicted light scattering distributions simulated from silicon bare substrates.