Patent ID: 7116397

Claim:
An exposure apparatus for exposing a substrate to light through a reticle, said apparatus comprising: a barrel configured to house therein a lens that directs the light; a first lens unit, said first lens unit separating a first space and a second space in said barrel from each other, said first lens unit having a first aperture and a second aperture; a second lens unit, said second lens unit separating the second space and a third space in said barrel from each other, said second lens unit having a third aperture and a fourth aperture; a first piping configured to supply a gas to said first space; and a second piping configured to discharge a gas out of said third space, wherein said first to fourth apertures are disposed in an order of first aperture, third aperture, second aperture, and fourth aperture, with respect to a rotational direction about an optical axis of said first and second lens units.