Patent ID: 7315348

Claim:
An exposure apparatus comprising: an original stage arranged to hold a reflective original having a pattern; a substrate stage arranged to hold a substrate; an illumination optical system arranged to emit exposure light along a first direction inclined from a direction of a reflection surface of the reflective original; a projection optical system arranged to project the pattern onto the substrate along a second direction using the exposure light reflected by the reflection surface of the reflective original; an original reference member arranged on said original stage or the reflective original; a substrate reference member, having a substrate mark, arranged on said substrate stage or the substrate; and a detector arranged to detect measuring light from the substrate mark of said substrate reference member, which is illuminated with the measuring light, the measuring light illuminating said substrate reference member being emitted to said original reference member along the first direction, reflected by said original reference member, and passing through said projection optical system along the second direction, wherein said original stage moves along the first direction and said substrate stage moves along a third direction substantially perpendicular to the second direction, associated with a detecting operation by said detector, and wherein a focal point of said projection optical system is obtained based on a change in a detection signal of said detector in accordance with movement of said original stage in the first direction and movement of said substrate stage in the third direction.