Patent ID: 7644387

Claim:
A semiconductor mask correcting device for inspecting a defective portion of a photo mask, which has a mask substrate and a mask pattern drawn on the mask substrate on the basis of mask data in which a main pattern and an assist pattern are previously stored as drawing data, and correcting the defective portion, the device comprising: a stage on which the photo mask is placed to be movable in parallel to the surface of the mask substrate; an image acquiring unit acquiring a mask image of the mask pattern; an extraction unit extracting only the main pattern from the mask data; an inspection unit matching and comparing the extracted main pattern with a drawn main pattern which is obtained from the mask image, along with inspecting whether the defective portion exists in the drawn main pattern in accordance with differences between both main patterns, and specifying the location of the defective portion; and a correction unit correcting the defective portion specified by the inspection unit by using a focused ion beam, wherein the extraction unit includes a recognition section recognizing the main pattern and the assist pattern as figures surrounded by only an outline, respectively, a specification section specifying a figure, which has a predetermined space from the nearest figure and of which at least a width and a length satisfy predetermined values, among the recognized figures as the assist pattern, and a main pattern extracting section extracting as the main pattern the figures other than the figure specified as the assist pattern.