Photo mask and fabrication process therefor

摘要

After forming a light shielding layer 2 of ruthenium in a thickness of 70 nm and a reflection preventing layer 3 of a ruthenium oxide in thickness of 30 nm, and a photosensitive resin layer, a sililated layer is formed by electron beam lithography and sililation. Etching is performed for the photosensitive resin layer, and the reflection preventing layer and the light shielding layer are dry etched using oxygen gas with taking the sililated layer as a mask. By this, dimensional precision of a pattern of a photo mask can be improved.