Alignment apparatus for use in exposure system for optically transferring pattern onto object

An exposure apparatus for exposing a wafer to exposure light to transfer a pattern to said wafer, comprising:

• an exposure light source for emitting a exposure light;
• a reticle on which pattern is formed, said reticle being illuminated with said exposure light emitted from said exposure light source, so that exposure light reflected from said reticle reflects said pattern of said reticle;
• a projection optical system for projecting said exposure light reflected from said reticle onto a wafer to form an image corresponding to said pattern of said reticle on said wafer, said projection optical system being positioned above said wafer;
• a light source optical system separated from said exposure light source for emitting coherent alignment light, the light source optical system being positioned at a distance from the water;
• a first optical system for leading said coherent alignment light emitted from said light source optical system toward said wafer through a first flexible light guide passage while bypassing said projection optical system and said reticle;
• a positional deviation detecting optical system for projecting said coherent alignment light directed through said first flexible light guide passage of said first optical system onto an alignment mark formed on said wafer to transform said coherent alignment light to beat light in which positional deviation information of said wafer is included, and for detecting said beat light, said positional deviation detecting optical system being disposed between said projection optical system and said wafer;
• a second optical system for directing said beat light detected in said positional deviation detecting optical system at a distance from said wafer through a second flexible light guide passage while passing through an outside of said projection lens and an outside of said reticle;
• a light-receiving optical system positioned at a distance from said wafer for receiving said beat light directed through said second flexible light guide passage of said second optical system to detect an amount of the positional deviation of said wafer included in said beat light;
• and
• moving means for moving said wafer on the basis of the positional deviation amount detected by said light-receiving optical system to align said wafer with said reticle, said pattern of said reticle being transferred to an image-formation area of said wafer moved by said moving means.