Patent ID: 7611639

Claim:
A method for manufacturing a glass substrate for an information recording medium, the manufacturing method comprising: forming a surface layer on a surface of a disk-shaped glass plate having a predetermined composition and a predetermined chemical resistance, with the surface layer having a composition differing from the predetermined composition and a chemical resistance that is lower than the predetermined chemical resistance; scrubbing the surface in a circumferential direction with an abrasive and a scrub member to form a texture including a plurality of projections each extending in a circumferential direction of the surface, the scrubbing forming the projections extending over the surface layer and a lower layer adjacent to the surface layer by removing the surface layer and the lower layer; and thereafter selectively removing an upper portion of the projections included in the surface layer with an etching liquid, wherein a ratio of a maximum peak height, R p , to an arithmetic mean roughness, R a , of the surface layer is 8 or less.