| 摘要 |
PROBLEM TO BE SOLVED: To detect a light beam reflected from a reflective surface for a short time at a high accuracy by receiving the light beam through a projection optical system and reference mark with driving a movable stage in the reflective surface inclining direction to obtain an image formed position information, using signals from a photo-detecting element. SOLUTION: A reference mark 50 is placed on a reticle surface 1 or at a position equivalent to the reticle surface, and an inclined reflective surface 12 is placed on a wafer stage 5. The image from the mark 50 is projected on the inclined reflective surface 12 and reflected beam from this surface 12 is guided to a photo-detecting element 103 through the mark 50. The stage 5 with the inclined surface 12 is continuously scanned horizontally in the inclined direction to determine the best image formed plane position of the mark 50 by a focus position detection control means 1100, using signals from the element 103 to calculate the best image formed plane position of an exposure region. |
