Core-shell particles and their manufacturing methods

Abstract

This invention provides a core-shell particle capable of reducing the surface roughness of a polished silicon dioxide film and achieving a sufficient polishing speed for the silicon dioxide film, and a method for manufacturing the same. The core-shell particle uses silicon dioxide particles as a core and has a shell, the shell being coated with the silicon dioxide particles and containing cerium oxide; the core-shell particle is characterized by: (1) the cerium oxide content in the core-shell particle is 4.0% to 80.0% by mass; (2) the crystallite diameter of the cerium oxide is 2.0 nm to 9.0 nm; and (3) the average secondary particle size retention rate after disintegration treatment is 0.70 to 1.0.