Patent ID: 7500904

Claim:
A method for manufacturing a glass substrate for an information recording medium manufactured by polishing the surface of a raw material glass plate, the method comprising: performing a first polishing process pad of a hard polisher to roughly polish the surface of the raw material glass plate to be smooth; and a second polishing process with a polishing pad of a soft polisher to finely polish the surface of the roughly polished glass raw plate to be smoother; wherein the surface of the polishing pad of the hard polisher that contacts the raw material glass has an average undulation height, as measured by a stylus measuring instrument with a measuring wavelength of 0.25 to 1.4 mm, of 4 to 25 μm, and a surface roughness as measured with a cut-off value of 2.5 mm, of 3 to 8 μm, wherein the polishing pad of the hard polisher is subjected to a pad dressing process before being used in the first polishing process to polish the surface of the polishing pad by sliding the polishing pad on a pad dresser, which includes abrasive grains, and wherein the pad dressing process is performed so that the product of a load applied to the polishing pad by the pad dresser (in g/cm 2 ) and a task time, in minutes, required for the pad dressing process is 500 to 3000.