Cerium salt, producing method thereof, cerium oxide and cerium based polishing slurry
AssigneeHitachi Chemical Company, Ltd.
InventorsKanshi Chinone, Seiji Miyaoka
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Abstract
A cerium salt wherein, when 20 g of the cerium salt is dissolved in a mixed liquid of 12.5 g of 6N nitric acid and 12.5 g of a 30% hydrogen peroxide aqueous solution, a concentration of an insoluble component present in the solution is 5 ppm or less by mass ratio to the cerium salt before dissolution and cerium oxide produced by processing the cerium salt at high temperatures. Scratch on a surface to be polished can be reduced when a cerium based polishing slurry containing the cerium oxide particles is used, since an amount of impurities in cerium oxide particles and cerium salt particles, raw material thereof, is reduced for high purification.
Claims12
A cerium salt wherein, when 20 g of the cerium salt is dissolved in a mixed liquid of 12.5 g of 6N nitric acid and 12.5 g of a 30% hydrogen peroxide aqueous solution, a concentration of an insoluble component present in the solution is 5 ppm or less by mass ratio.
A producing method of a cerium salt where through obtaining at least one kind of cerium-containing intermediate from a cerium compound a precipitating agent is added to obtain a precipitate of a cerium salt, comprising at least one time of separating and removing an insoluble component from the cerium-containing intermediate in a solution state.
Cerium oxide in which when 20 g of the cerium oxide is dissolved in a mixed liquid of 12.5 g of 6N nitric acid and 12.5 g of a 30% hydrogen peroxide aqueous solution, a concentration of an insoluble component present in the solution is 10 ppm or less by mass ratio.
A cerium based polishing slurry in which when 20 g of the cerium based polishing slurry is dissolved in a mixed liquid of 12.5 g of 6N nitric acid and 12.5 g of a 30% hydrogen peroxide aqueous solution, a concentration of an insoluble component present in the solution is 10 ppm or less by mass ratio.
Dependencies are inferred from the claim text.