Patent ID: 8873830

Claim:
A method for extracting a contour of a pattern on a photo mask, the method comprising: acquiring, by a scanning electron microscope, information about a two-dimensional distribution of secondary electron intensity or reflection electron intensity for a measurement target pattern formed on a photo mask; extracting, by a first method, an edge position of an edge for correction value acquisition included in the measurement target pattern based on the information about the two-dimensional distribution; extracting, by a second method, an edge position of the edge for correction value acquisition based on the information about the two-dimensional distribution; acquiring a difference between the edge position extracted by the first method and the edge position extracted by the second method, as a correction value; extracting, by the second method, an edge position of a desired edge included in the measurement target pattern based on the information about the two-dimensional distribution; and correcting the edge position of the desired edge based on the correction value, wherein the edge for correction value acquisition is determined based on design data about the measurement target pattern.