| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a substrate for a mask blank having high flatness of a prescribed value or less, high symmetry on the substrate main surface of the substrate after polished, and the suppressed surface defect on the main surface.SOLUTION: A method for producing a substrate for a mask blank includes a polishing step in which a substrate held by a carrier is sandwiched between both polishing pads of both upper and lower surface plates having the polishing pads on rotating faces, a substrate 100 is relatively moved to polishing faces of the polishing pads while supplying polishing liquid, and both main surfaces of the substrate are polished. The polishing pad is composed of at least a base material, and a nap layer formed on the base material and comprising a foamed resin having open holes on the surface, and 100% modulus of the resin forming the snap layer is 11 MPa or more and 20 MPa or less. |
