| 摘要 |
PURPOSE: To provide a projection aligner which is hardly affected by residual aberrations or thermal aberrations caused by exposure in an projection optical system and capable of carrying out a focus measurement stably. CONSTITUTION: A projection aligner is equipped with a projection optical system which projects a pattern of an object onto a substrate and a focus position detecting means which detects the image of a measurement mark having repetitive patterns for detecting the focus position of the projection optical system through the intermediary of the projection optical system. Provided that a numerical aperture is represented by NA, a projection magnifying factor isβ, wavelength of exposure light is represented byλ, and the period of the repetitive patterns is P, P is so set as to satisfy a formula, 2λ/(NAβ)<P<16λ/(NAβ). |
