| 摘要 |
PURPOSE:To enable accurate, sure and quick alignment by synthesizing and observing the reflected light from the second object after transmitted through a projection lens and the reflected light from the first object in every wavelength, the first and the second objects being illuminated by exposure wavelength light and non-exposure wavelength light. CONSTITUTION:An illumination system which illuminates the first region on the first object 1 and the second region on the second object 3 with exposure wavelength light, an illumination system which illuminates the third region on the first object 1 and the second region on the second object 3 with non-exposure wavelength light, a movable mirror 4 which can be inserted in or removed from the exposure luminous flux between the first object 1 and a projection lens 2 and introduces the reflected light from the second region entered through the projection lens 2 when the mirror is inserted to a branch optical path outside the exposure luminous flux, the means which separate the reflected light passing through the branch optical path into exposure wavelength light and non-wavelength light, the means for synthesizing and observing the exposure wavelength light from the first region and the exposure wavelength light from the second region and the means tor synthesizing and observing the non- exposure wavelength light from the third region and the non-exposure wavelength light from the second region are provided. |
