Patent attributes
An exposure method includes preparing a photomask having first and second main openings by which corresponding patterns are to be formed in a photo resist and first and second assist openings by which no corresponding patterns are to be formed in the photo resist, preparing an illumination having first and second light emitting areas, and irradiating the photo resist with illumination light from the illumination via the photomask, the first light emitting area and the second light emitting area being symmetric with respect to a center of the illumination, the first light emitting area and the second light emitting area containing a first point and a second point, respectively, the first point and the second point being symmetric with respect to the center of the illumination, the first point and the second point being symmetric with respect to a straight line extending through the center of the illumination.
