Patent ID: 7119878

Claim:
An exposure apparatus for exposing a substrate to light via a mask, said apparatus comprising: an optical system configured to direct light from a light source to the substrate via the mask; a barrel which holds a plurality of optical elements included in said optical system; a casing which accommodates therein said plurality of optical elements and said barrel; a first supplying line having a first port which is arranged in a first space, the first space being a space surrounded by said barrel and said plurality of optical elements; a second supplying line having a second port which is arranged in a second space, the second space being a space inside said casing and outside said barrel, said plurality of optical elements and the first space; a first discharging line having a third port which is arranged in the first space; a second discharging line having a fourth port which is arranged in the second space; a supplier configured to supply an inert gas into the first and second spaces through said first and second supplying lines; and an exhauster configured to exhaust gas from the first and second spaces through said first and second discharging lines.