MASK BLANK SUBSTRATE, MASK BLANK, EXPOSURE MASK, MASK BLANK SUBSTRATE MANUFACTURING METHOD, AND SEMICONDUCTOR MANUFACTURING METHOD

摘要

In a mask blank substrate to be chucked by a mask stage of an exposure system, the flatness of a rectangular flatness measurement area excluding an area of 2 mm inward from an outer peripheral end surface on a main surface of the mask blank substrate on its side to be chucked by the mask stage is 0.6 μm or less, and at least three of four corner portions of the flatness measurement area each have a shape that rises toward the outer peripheral side.