METHOD FOR PRODUCING GLASS SUBSTRATE FOR INFORMATION RECORDING MEDIUM, POLISHING APPARATUS AND GLASS SUBSTRATE FOR INFORMATION RECORDING MEDIUM

摘要

An information recording medium glass substrate manufactured by polishing the surface of a raw material glass plate. The polishing is divided into two steps, a step for performing a first polishing process to roughly polish the surface of the raw material glass plate to be smooth and a step for performing a second polishing process to finely polish the surface of the roughly polished raw material glass plate to be smoother. The second polishing process, using a polishing pad made of foam, is divided into two stages, pre-polishing with a polishing agent including abrasive grains of cerium oxide and post-polishing with a polishing agent including abrasive grains of silicon oxide. A rinsing process is performed between the pre-polishing and the post-polishing to rinse the raw material glass plate after the pre-polishing with a washing liquid to wash away the abrasive grains collected in the polishing pad in pre-polishing during the rinsing process.