Patent ID: 7455785

Claim:
A method of manufacturing a mask blank by forming, over a principal surface of a glass substrate, a thin film for transferring a pattern onto an object, the method comprising the steps of: polishing the principal surface of the glass substrate; measuring a flatness and a surface profile on the principal surface of the glass substrate to obtain measured data; locally modifying a flatness and a profile of the principal surface on the basis of the measured data at a convex portion projected relative to a reference surface, so that the principal surface has a convex shape or a concave shape and has a desired flatness; forming, over the principal surface, the thin film that causes an optical change to exposure of light and that has a tensile stress when the principal surface has the convex shape and has a compressive stress when the principal surface has the concave shape, by carrying out sputtering, so that the flatness of the mask blank has a variation resulting from a film stress of the thin film and is not greater than 1 micron meter.