Method for amending a photomask

A method for amending a defective mask pattern of a photomask which comprises a plurality of same mask patterns each of which comprises a plurality of pattern components, this method comprising the steps of:

• (a) representing an enlarged image of a normal mask pattern having the same pattern layout as that of the defective mask pattern to be amended in a view field;
• (b) irradiating a pattern component of said normal mask pattern by a spotlight;
• (c) aligning said spotlight with one of the pattern components of said normal mask pattern, said one of the pattern components corresponding to the pattern component of the defective mask pattern to be amended, so that the shape of said spotlight coincides with that of the one of the pattern components of said normal mask pattern;
• (d) representing at least one base mark optically in said view field said base mark including first and second independently movable base lines;
• (e) aligning at least one base mark with at least one pattern component near the irradiated portion while said normal mask pattern is irradiated by the spotlight;
• (f) fixing the position of said base mark relative to the position of said irradiated portion in the condition that said spotlight is aligned with the pattern component of sid normal mask pattern and said base mark is aligned with said one pattern component near the irradiated portion;
• (g) representing the defective mask pattern formed on the same photomask on which said normal mask pattern is formed in said view field by shifting said photomask so as to replace the normal mask pattern with said defective mask pattern;
• (h) aligning said base mark with a pattern component near the defective pattern component in the same manner as the alignment of the normal mask pattern, with the base mark being kept fixed with respect to the spotlight in the state of step (f);
• and
• (i) irradiating the defective mask pattern with an exposure light having the same shape as that of said spotlight, thereby amending the defective pattern component.