Uniform deep ultraviolet radiant source for sub micron resolution systems

An optical system for providing an ultraviolet radiation pattern for photolithography, comprising:

• an elongated pressurized mercury lamp operative to support an elongated arc of a given length to width ratio;
• an ellipsoidal reflector symmetrically surrounding said lamp and having an inner lightly diffused surface for reflecting radiation from said lamp to provide a circular object source pattern of a given diameter symmetrically disposed about an optical system axis;
• a short focal length condenser lens assembly located on said axis and adapted to receive said object source pattern to provide at an output a reduced diameter circular pattern indicative of an effective image source;
• an entrance pupil lens and a collimation lens positioned along said axis and operative to provide at an output a collimated beam of high uniformity and stable ray bundles for projecting said beam to a mask/wafer plane to illuminate said mask and wafer with said beam.

An ultraviolet radiation source apparatus, comprising:

• a mercury lamp pressurized between 1 to 1.5 atmospheres operating to support an elongated arc having a length to width ratio greater than 20;
• an ellipsoid reflector having a lightly diffused inner surface to reflect the ultraviolet illumination energy radiated by said mercury lamp, and thereby to provide an effective circular object source of a given diameter;
• a condenser lens system responsive to said effective circular object source to provide an effective image source of a diameter reduced by a factor of 6 to 10;
• and
• means responsive to said effective image source to direct said effective image source to a given target area at a given plane.