Abstract: The present invention provides a sulfonium compound represented by the formula (I): wherein Q1 and Q2 each independently represent a fluorine atom or a C1-C6 perfluoroalkyl group, and A+ represents an organic counter ion.

Abstract: The present invention provides a sulfonium compound represented by the formula (I): wherein Q1 and Q2 each independently represent a fluorine atom or a C1-C6 perfluoroalkyl group, and A+ represents an organic counter ion.

Abstract: The present invention provides a chemically amplified positive resist composition comprising (i) a polymer which is insoluble or poorly soluble in an alkali aqueous solution but becomes soluble in an alkali aqueous solution by the action of an acid, (ii) an acid generator, and (iii) a compound of the formula (I). The present invention also provides an ester derivative useful as a component of the chemically amplified positive resist composition, and process for producing the ester derivative.

Abstract: An abrasive composition for polishing a substrate for a magnetic recording disc is described, which comprises finely divided zirconium oxide particles, an abrasion promoter, an optional water-soluble oxidizing agent, and water. This abrasive composition is used for polishing a substrate for a magnetic recording disc by a process wherein the substrate is polished with a pad while the abrasive composition is supplied between the substrate and the pad, and at least one of the pad and the substrate is rotated. The contents of the finely divided zirconium oxide particles, the abrasion promoter and the optional water-soluble oxidizing agent are 2-20 wt. %, 1-20 wt. % and up to 10 wt. %, respectively, based on the weight of the abrasive composition as used for polishing the substrate.