PHOTOMASK-FORMING GLASS SUBSTRATE AND MAKING METHOD

摘要

PURPOSE: A glass substrate for a photo mask, and a manufacturing method thereof are provided to secure the productivity of the glass substrate with the controlled surface shape change. CONSTITUTION: A manufacturing method of a glass substrate for a photo mask comprises the following steps: setting two belt-shaped domains and a main surface domain containing the belt-shaped domains; calculating a minimum square flat surface based on the distance of each coordinate within an arbitrary common standard flat surface on the main surface domain; comparing the minimum square flat surface(6) with the actual shape of the two belt-shaped domains; calculating the removal amount on each coordinate within the belt-shaped domains by the difference obtained from the previous step; and removing a substrate surface unit on the two belt-shaped domains by local grinding or local etching.