Patent ID: 7300335

Claim:
A method for manufacturing a glass substrate of an information recording medium by polishing a surface of a glass workpiece with a polishing pad, wherein the polishing pad comprises a nap layer having an inner layer and an outer layer, wherein the inner layer comprises a plurality of closed cells, and a plurality of pores are formed on the surface of the outer layer, and wherein the sizes of said pores are minute compared to those of said closed cells, wherein polishing includes a first polishing step for subjecting a surface of the glass workpiece to rough polishing, and a second polishing step for subjecting the surface of the glass workpiece to precision polishing so that the surface is further smoothed, wherein the polishing pad is used in a second polishing step, wherein said polishing pad comprises from 400 to 10,000 of said pores in 1 mm 2 , wherein a compression deformation amount of the polishing pad is 40 to 60 μm, wherein the compression deformation amount is computed by subtracting the thickness of the polishing pad when compressed to the limit along the thickness from the original thickness, and, wherein said pores have an opening size of from 10 to 60 μm.