The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 03, 2005
Filed:
Feb. 19, 2004
Isao Ota, Nei-gun, JP;
Kenji Tanimoto, Nei-gun, JP;
Tohru Nishimura, Sodegaura, JP;
Nissan Chemical Industries, Ltd., Tokyo, JP;
Abstract
There is provided an abrasive used for polishing a substrate which comprises silica as a main component, for example a rock crystal, a quartz glass for photomask, for CMP of an organic film, Inter Layer Dielectric (ILD) and shallow trench isolation of a semiconductor device, or for polishing a hard disk made of glass. A sol which particles are dispersed in a medium, wherein the particles have a particle size of 0.005 to 1 μm and comprise as a main component crystalline cerium oxide of the cubic system and as an additional component a lanthanum compound, a neodymium compound or a combination thereof, wherein the additional component is contained in X/(Ce+X) molar ratio of 0.001 to 0.5 in which X is lanthanum atoms, neodymium atoms or a combination thereof. The sol is prepared by reacting an aqueous solution which a cerium (III) salt is mixed with a lanthanum (III) salt and/or a neodymium (III) salt, with an alkaline substance to give a suspension in which cerium (III) hydroxide is homogeneously mixed with lanthanum (III) hydroxide and/or neodymium (III) hydroxide, and blowing oxygen or a gas containing oxygen into the suspension.