Method for preparing photomask blank, photomask blank, method for preparing photomask, photomask, and metallic chromium target

摘要

A method for preparing a photomask blank comprising a transparent substrate and a chromium-containing film contiguous thereto involves the step of depositing the chromium-containing film by sputtering a metallic chromium target having an Ag content of up to 1 ppm. When a photomask prepared from the photomask blank is repeatedly used in patternwise exposure to ArF excimer laser radiation, the number of defects formed on the photomask is minimized.