GLASS SUBSTRATE AND METHOD FOR FLATTENING GLASS SUBSTRATE

摘要

PROBLEM TO BE SOLVED: To provide a glass substrate having high flatness, particularly a glass substrate having 0.04-1.3 nm flatness per 1 cm<2> surface area as a silica glass substrate for a photomask used in a photolithographic process important to the production of IC, or the like, a silica glass substrate whose utilization is expected in the fields of microelectronics, microanalysis, or the like, a silica glass chip, or the like. SOLUTION: The surface of a glass substrate is subjected to local plasma etching to obtain the objective surface-flattened glass substrate.