A method of making a semiconductor device includes defining a pattern including a plurality of sub-patterns on the photomask in the pattern region based on the identifying information. The defining of the pattern includes defining a first sub-pattern of the plurality of sub-patterns having a first spacing from a second sub-pattern of the plurality of sub-patterns, wherein the first spacing is different from a second spacing between the second sub-pattern and a third sub-pattern of the plurality of sub-patterns, or rotating the first sub-pattern about an axis perpendicular to a top surface of the photomask relative to the second sub-pattern.