A light-shieldable film is formed on one principal plane of an optically
transparent substrate, and the light-shieldable film has a first
light-shieldable film and a second light-shieldable film overlying the
first light-shieldable film. The first light-shieldable film is a film
that is not substantially etched by fluorine-based (F-based) dry etching
and is primarily composed of chromium oxide, chromium nitride, chromium
oxynitride or the like. The second light-shieldable film is a film that
is primarily composed of a silicon-containing compound that can be etched
by F-based dry etching, such as silicon oxide, silicon nitride, silicon
oxynitride, silicon/transition-metal oxide, silicon/transition-metal
nitride or silicon/transition-metal oxynitride.