| 摘要 |
PROBLEM TO BE SOLVED: To provide an illumination optical system of an aligner, which can minimize variations in illumination on a mask, even when a plurality of primary light sources are used to illuminate facet-eye lenses as secondary light sources. SOLUTION: An illumination optical system of an aligner includes a plurality of primary illumination light sources 2 to 5, a first group of facet-eye lenses 12 to 15 arranged in light paths of illuminating lights P1 to P4, emitted from the primary light sources 2 to 5 to be illuminated from mutually different directions by the primary light sources, a group of deflection optical systems for deflecting the illumination lights P1 to P4 passed through the first group of facet-eye lenses 12 to 15 toward an identical direction where a mask 25 is present, and a second group of facet-eye lenses 16 to 19 as secondary light sources arranged in light paths of the illumination lights deflected by the group of deflection optical systems 20 to 23. The illumination optical system acts to illuminate the mask 25 with the illumination light P5 which passed through the second group of facet-eye lenses 16 to 19. |
