| 摘要 |
In a stage slit type focus position detecting system, an opening pattern unit (11A) on a reticle (10) is illuminated with exposure light (IL1) from a light source system (1), and light passing through the opening pattern unit (11A) is received through a projection optical system (13) and a reference pattern plate (23). In a stage emission type focus position detecting system, the reference pattern plate (23) is illuminated with illuminating light from a light source (35), and light passing through the reference pattern plate (23) and further going and returning through the projection optical system (13) is received by a photoelectric detector (42). An oblique incidence type AF sensor has a light-transmitting system (24) and a converging optical system (28). Thus, even if the projection optical system absorbs thermal energy of exposure light and thus causes the position of its image-formation plane to change, calibration of the oblique incidence type AF sensor can be readily made by using the stage slit type focus position detecting system and the stage emission type focus position detecting system.
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