PURPOSE: To obtain an exposure mask which is hardly peeled off again by bringing a supplementary film into direct contact with an insulator substrate which is exposed by removing selectively a defect and a deficit part of a pattern film.

CONSTITUTION: The supplementary film 8a provided after the defect and deficit parts and their peripheries of the metallic pattern film are removed is a chromimum film. The supplementary film 3a contacts directly the surface of the substrate 1 at the defect and deficit parts of the pattern 2, so it is stuck more tightly. Further, the same effect is obtained by removing only part of the defect and deficit parts.