Patent ID: 6545746
Filing Date: 2003-04-08
Classification: G03F

Abstract:
An exposure apparatus comprising:an illumination optical system that illuminates a mask having a transfer pattern formed thereon under illuminating light, said illumination optical system being positioned on an optical path of said illuminating light; a projection optical system that projects an image of the pattern on said mask onto a photosensitive substrate, said projection optical system being positioned on the optical path of said illuminating light; a plurality of casings that independently accommodate said illumination optical system and said projection optical system; a first gas supply device that is connected to at least one of said casings and is adapted to supply said first gas into said casing; a second gas supply device that is connected to at least one of said casings and is adapted to supply said second gas into said casing, an absorbency index of said illuminating light of said second gas being higher than that of said first gas; and a gas replacement device that is connected to said first gas supply device and said second gas supply device, said gas replacement device controlling the selective supply of said first gas and said second gas in such a way that said first gas is supplied into at least one of said casings under a first condition in which said image of the pattern is transferred onto said photosensitive substrate and said second gas is supplied into at least one of said casings under a second condition which is different from the first condition.