Method for manufacturing photomask blank

Abstract

The present invention relates to a photomask blank obtained by forming a resist film after performing a silylation process on a silicon-containing inorganic film and provides a method for manufacturing a photomask blank having at least a silicon-containing inorganic film over a transparent substrate and a resist film on the inorganic film, comprising: forming the silicon-containing inorganic film; heat treating the formed silicon-containing inorganic film at a temperature more than 200° C. under an atmosphere containing oxygen; performing a silylation process after the heat treatment; and then forming the resist film by application. The method can inhibit generation of defects due to resist residues or the like after development.

Dependencies are inferred from the claim text.