Condenser for extreme-UV lithography with discharge source

A condenser system for use with a scanning ringfield camera comprising:

• a discharge source of radiation;
• at least two sets of collector mirrors facing said discharge source wherein each set comprises at least two quasi-grazing incidence mirrors that are coated with a radiation reflective material and that are arranged such that radiation is reflected at a quasi-grazing incidence angle, with each set of collector mirrors having one focus at the radiation source and a second focus filling the object field of the camera at the radius of the ringfield and each producing a beam of radiation;
• and
• a corresponding number of sets of correcting mirror means which are capable of light beam translation or rotation, or both, such that all of the beams of radiation pass through the entrance pupil of the camera and form a coincident arc image at the ringfield radius.