CERIA-BASED COMPOSITE FINE PARTICLE DISPERSION, PRODUCTION METHOD THEREFOR, AND POLISHING ABRASIVE GRAIN DISPERSION INCLUDING CERIA-BASED COMPOSITE FINE PARTICLE DISPERSION

摘要

The present invention addresses the problem of providing a ceria-based composite particle dispersion which is capable of performing polishing at high speed, even for silica films, Si wafers, and difficult to process materials, and which is simultaneously capable of achieving high surface accuracy. The present invention solves the abovementioned problem by providing a ceria-based composite fine particle dispersion which includes ceria-based composite fine particles which have an average particle size of 50-350 nm, and which have the following characteristics. The ceria-based composite fine particles are each provided with: a mother particle; a cerium-containing silica layer; child particles; and a layer including readily soluble silica. The mother particle has amorphous silica as a main component. The child particles have crystalline ceria as a main component. The ratio of the mass of the layer including the readily soluble silica to the mass of the ceria-based composite fine particles is in a specific range. The mass ratio of silica to ceria in the ceria-based composite fine particles is in a specific range. When the ceria-based composite fine particles are subjected to X-ray diffraction, only the crystal phase of the ceria is detected. The average crystallite size of the crystalline ceria measured by subjecting the ceria-based composite fine particles to X-ray diffraction is 10-25 nm.