| 摘要 |
PROBLEM TO BE SOLVED: To provide a lighting optical system for alignment which can form an illumination field having an even distribution of illumination and enough illumination NA(number of apertures) even if excimer laser is used as a source of light and also provide an aligner using the lighting optical system. SOLUTION: In this optical system and aligner, light from a source of excimer laser light is led to a light guide and an index plate 19 for alignment is illuminated by light which has passed through the light guide. In this case, a diffusion plate 15 is located on an optical axis near either an incident end or an emission end of the light guide or near each of the ends and a driver for rotating the diffusion plate 15 is also installed. Or, a driver for rocking the light guide is installed. |
