SUBSTRATE FOR PHOTOMASK BLANK, PHOTOMASK BLANK AND PHOTOMASK

摘要

PURPOSE: A transparent substrate for a photo mask blank, a manufacturing method thereof, and a photo mask using thereof are provided to improve the quality of the photo mask by reducing the generation rate of particles from a side surface and a chamfer surface of the transparent substrate. CONSTITUTION: A transparent substrate(10) for a photo mask blank includes a main surface(11), a rear surface(12), and a side surface(13). Chamfer surfaces(14) are formed in between the main surface and the side surface, and the rear surface and the side surface. The cross section of the chamfer surfaces is an arched shape. The length of one side of the transparent substrate is longer than 300mm. The surface roughness of the side surface and the chamfer surfaces is 0.03-0.3 micrometers.