Polishing composition

摘要

A polishing composition containing a silica, an acid, a surfactant, and water, wherein (a) the acid has solubility in water at 25° C. of 1 g or more per 100 g of an aqueous saturated solution; (b) the surfactant is a sulfonic acid represented by the formula (1) or (2), or a salt thereof; and (c) the polishing composition has a pH of a specified range; and a polishing process of a substrate using the polishing composition are provided. The polishing composition is suitably used, for example in polishing a substrate for disk recording media such as magnetic disks, optical disks and opto-magnetic disks.

主权项

1. A method for manufacturing a hard disk substrate, comprising the steps of:
feeding a polishing composition at a flow rate of 0.05 mL/minute or more per 1 cm2 of a substrate to be polished; and polishing the substrate at a polishing pressure of from 5 to 50 kPa; wherein said polishing composition comprises a silica, an acid, a surfactant, an oxidizing agent, and water, wherein:
(a′) the acid has solubility in water at 25° C. of 1 g or more per 100 g of an aqueous saturated solution;(b′) the surfactant is a sodium salt of a sulfonic acid represented by the following formula (2):
R′—O-(AO)n—SO3H  (2)wherein R′ is a hydrocarbon group having 12 carbon atoms; AO is an oxyalkylene group having 2 carbon atoms; and n, which is an average number of moles of alkylene oxide added, is from 2.0 to 3.0; and
(c′) the polishing composition has a pH of from 0 to 3; wherein the surfactant is contained in an amount of from 0.01 to 2% by weight of the polishing composition; wherein the hard disk substrate has a roll-off of 1.05 nm/mg or less; and wherein primary particles of said silica have an average particle size of 5 to 35 nm.