| abstract |
PROBLEM TO BE SOLVED: To suppress scratches and etch pits on a substrate surface and polish the substrate surface flatly. SOLUTION: A silica sol having a solid concentration of 5 to 50% by weight in which spherical silica fine particles whose surfaces are treated with silica and alumina are dispersed in an aqueous dispersion medium, and a) the average particle size of the spherical silica fine particles is 20. -110 nm, b) The number of coarse particles having a particle diameter of 800 nm or more is 3000 particles / ml or less per 1% by weight of the spherical silica fine particles, c) the pH range is pH 1-4 or pH 8-11, and d) inorganic anions. Satisfies the respective conditions of 20 ppm or less. [Selection figure] None |