METHOD OF MANUFACTURING PHOTOMASK BLANK AND METHOD OF MANUFACTURING PHOTOMASK

摘要

PURPOSE: A method for manufacturing a photomask blank and a method for manufacturing a photomask are provided to improve the resistance of a thin film to exposed light having a wavelength less than 200nm and to improve the lifespan of the mask. CONSTITUTION: A method for manufacturing a photomask blank comprises the following steps: forming a thin film containing metal and silica on a transparent substrate(1); and modifying the main surface of the thin film in advance to maintain the transcription property of a thin film pattern when light, having a wavelength less than 200nm, is irradiated on the thin film pattern of the photomask. A layer containing silica and oxygen is formed on the superficial layer of the thin film.