A high concentration silica slurry can be used for polishing of
substrates, such as semiconductor materials. The slurry contains a silica
powder dispersed in an solvent. The silica slurry has a silica
concentration of more than 50% by weight and a viscosity of less than
1000 mPas, wherein the silica powder has a ratio DL/DT of less than 1.3,
wherein DL is an average particle size of the silica powder measured by a
laser diffraction particle size distribution method and DT is an average
primary particle size of the silica powder measured by a TEM photography
observation, and wherein the silica powder has an average primary
particle size of from 0.08 .mu.m to 0.8 .mu.m.