| 摘要 |
<p>A purge cover is equipped whose upper end is connected to an illumination unit and the lower end has a pair of plate sections facing an upper surface of a reticle stage and a reticle via a predetermined clearance. Therefore, gaseous circulation can be substantially blocked via the clearance between the reticle stage and the plate sections. This allows a space which is almost airtight surrounded by the purge cover, the reticle stage and/or the reticle to be formed on the optical path of the illumination light that reaches the projection optical system from the illumination unit. Further, the space above which is almost airtight serves as a purge space that is purged with clean dry air and the like.</p> |
