Patent ID: 6420269
Filing Date: 2002-07-16
Classification: C01F,C01P,C09K,H01L

Abstract:
A cerium oxide abrasive for polishing an insulating film formed on predetermined substrates, which comprises a slurry of cerium oxide grains as dispersed in water, whereinsaid cerium oxide grains are obtained, without being baked, by oxidizing a water-insoluble, trivalent cerium compound as dispersed in water, with an oxidizing agent, wherein said cerium oxide grains have a specific surface area of not smaller than 50 m2/g and not larger than 500 m2/g, and an apparent density as measured in a still standing method of 0.8 g/ml to 1.30 g/ml, wherein the number of primary grains of said cerium oxide grains having a primary grain size of not larger than 10 nm are not smaller than 90% of the total number of primary grains; wherein the number secondary grains as formed through aggregation of said primary grains so that to have a secondary grain size of not larger than 1 &mgr;m are not smaller than 90% of the total number of the secondary grains, and said secondary grains each give an outline with no edges having an angle of smaller than 120Â°; and a powdery X-ray diffraction pattern of said cerium oxide grains gives a main peak having a half-value width of not smaller than 0.4Â° and not larger than 0.5Â°.