Glass substrate for mask blank, and method for producing the same

Abstract

A glass substrate for a mask blank includes two main surfaces facing each other and surfaces to be chamfered. The surfaces to be chamfered are provided peripherally around the two main surfaces. A flatness of one of the main surfaces is 100 nm or less. On the surface to be chamfered from which substrate corner parts are excluded, each of the substrate corner part being portions where a distance from an outer end of a two-dimensional projection profile of the one of the main surfaces and the surface to be chamfered is within 10 mm, a waviness measured in a range of 2 mm at an arbitrary part in a direction parallel to one side closest to the surface to be chamfered in the two-dimensional projection profile is 50 nm or less.

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