PHOTO MASK BLANK, METHOD FOR MANUFACTURING PHOTO MASK BLANK, AND PHOTO MASK

摘要

PURPOSE: A photomask blank, a manufacturing method thereof, and a photomask are provided to reduce the manufacturing cost of a photomask blank by minimizing the auxiliary pattern defect caused by the edge bead. CONSTITUTION: More than one layer of metal layers(12) including more than one kind of metal is formed on a transparent substrate(11). A resis film(13) is formed on the front side of the metal layer. The resist film comprises an edge bead(14). The edge bead is formed on the periphery of the resist film. The edge bead has the film thickness being thicker than the average film thickness of the resist film.