CUTTING METHOD OF DISK-SHAPED GLASS SUBSTRATE, MANUFACTURING METHOD OF MAGNETIC RECORDING MEDIUM GLASS SUBSTRATE

摘要

PROBLEM TO BE SOLVED: To provide a cutting method of a disk-shaped glass substrate capable of reducing the size of a clamshell-shaped crack generated near a cutting line on a principal plane of the disk-shaped glass substrate when the disk-shaped glass substrate is cut out of a plate-like glass substrate.SOLUTION: A cutting method of a disk-shaped glass substrate includes causing a core drill 11 to penetrate from one principal plane to the other principle plane 122 of a plate-like glass substrate 12 to cut out a disk-shaped glass substrate. A crack prevention part 31 containing a crack 311 is formed at least on the other principle plane 122 of the plate-like glass substrate 12.