METHOD OF PRODUCING GLASS SUBSTRATE FOR USE IN INFORMATION RECORDING MEDIUM, AND INFORMATION RECORDING MEDIUM

摘要

A method of producing a glass substrate for use in an information recording medium comprises preparing a glass blank (S10), forming a substantially circular glass substrate using the glass blank (S20), performing a lapping process with respect to the glass substrate (S31), performing polishing processes with respect to the glass substrate (S33,S34), removing multiple deposits that have adhered to the main surface of the glass substrate by cleaning the main surface of the glass substrate (S40), and performing a chemical strengthening process on the main surface of the glass substrate (S50). The main surface of the glass substrate is washed such that, of the deposits, the number of deposits having a size of no more than 0.1µm is no more than 10 per 2.5 inch disk, the deposits being detected on the basis of respective reflecting beams by irradiating the main surface of the glass substrate in different directions with laser light of two wavelengths.