| 摘要 |
<p>An exposure apparatus for transferring a pattern on a mask (M) onto a photosensitive substrate (W) via a projection-optical system (L1-L23,Mc,Mp1,Mp2) can reduce gas fluctuation even if the length of the optical path through gas is relatively long, and even if the diameter of light flux through the gas is relatively large. The projection-optical system satisfies the condition <MATH> where lambda is a wavelength of exposure light used in the apparatus, SIGMA i is a sum over gas sections i in an optical path from the mask to the photosensitive substrate, Li is a length of a gas section i along the optical axis , in m, and Ri is an average of a mask-side diameter and a substrate-side diameter of a light flux in each gas section, the light flux emerging from a maximum image height and advancing within meridional plane, wherein at least one gas section i is filled with helium or neon. <IMAGE></p> |
