Abstract: A condenser lens system is provided for forming an effective circular source of NUV-DUV radiation which is the telecentric stop of the system and is characterized by a short focal length and higher marginal irradiance to compensate for marginal cosine losses. The system utilizes a long arc medium/low pressure mercury lamp which is surrounded by a large paraboloidal reflector and is mounted below the focal point of the reflector to generate a converging radiation beam directed to the condenser lens system. The system then projects the effective circular source of NUV-DUV radiation to a lens system comprising two plano convex lenses to convert the effective circular source into a collimated beam for out-of-contact printing of large substrates. The highly collimated and spatially coherent beam can be used to irradiate a telecentric objective for projection exposure on wafer steppers or flood exposure systems.

Abstract: An optical system is provided for forming an effective image source of DUV radiation which is characterized by symmetry, high uniformity of ray bundle distribution, high spatial stability and high brightness. The system utilizes an elongated medium/low pressure mercury lamp which is surrounded by a large lightly diffused ellipsoidal reflector. The elongated medium/low pressure mercury source is converted by the lightly diffused ellipsoidal reflector into a large circular radiant source which becomes the effective object source of a condenser lens system. The effective object source of the ellipsoidal reflector is projected through a small diameter condenser lens system where it is reduced between six to ten times to an effective image source.