Reflective fly's eye condenser for EUV lithography

摘要

An illumination source or condenser (10) used to project the image of a reticle (24) onto a photosensitive substrate (28) used in photolithography having a first reflective fly's eye, faceted mirror, or mirror array (16) with predeterminedly positioned facets or elements (42) and a second reflective fly's eye, faceted mirror, or mirror array having predeterminedly positioned facets or elements (52) for creating a desired radiant intensity, pupil fill, or angular distribution. A source (12) of extreme ultraviolet electromagnetic radiation is provided to a first fly's eye or mirror array (16) with arcuate shaped facets or elements (42). The arcuate shaped facets or elements (42) are positioned to create an image of the source (12) at corresponding a facet (52) in a second reflective fly's eye or mirror array (18). A desired shape and irradiance together with a desired radiant intensity, pupil fill, or angular distribution is obtained. An arcuate illumination field or image is formed with high efficiency in a compact package. The illumination system of the present invention facilitates imaging of feature sizes as small as 0.025 microns, utilizing electromagnetic radiation in the extreme ultraviolet and ranging from 1 nanometer to approximately 157 nanometers.