Patent ID: 7517621
Filing Date: 2009-04-14
Classification: G03F

Abstract:
1. An exposure method comprising: preparing a photomask having first main openings and second main openings by which corresponding patterns are to be formed in a photo resist and first assist openings and second assist openings by which no corresponding patterns are to be formed in the photo resist; preparing an illumination having a first light emitting area and a second light emitting area; and irradiating the photo resist with illumination light from the illumination via the photomask, the first main openings being arranged at a first pitch on a first straight line extending in a first direction, the second main openings being arranged at the first pitch on a second straight line extending in the first direction and being away from the first straight line by a first distance, the second main openings being displaced relative to the first main openings by half the first pitch in the first direction, the first assist openings being arranged at the first pitch on a third straight line extending in the first direction and being away from the first straight line by the first distance and away from the second straight line by double the first distance, the first assist openings being displaced relative to the first main openings by half the first pitch in the first direction, the second assist openings being arranged at the first pitch on a fourth straight line extending in the first direction and being away from the second straight line by the first distance and away from the first straight line by double the first distance, the second assist openings being displaced relative to the second main openings by half the first pitch in the first direction, 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 in a second direction perpendicular to the first direction.