Abstract: A reflective afocal telescope is described herein that has multiple field of views and can be packaged in a compact arrangement. In one embodiment, the reflective telescope includes two entrance pupils, a primary mirror, a secondary mirror, a tertiary mirror, a quaternary mirror, a moveable fold mirror and an exit pupil. The fold mirror can be moved into a non-bypass position and out of the way such that the incident beams transverse the primary, secondary, tertiary and quaternary mirrors and form a collimated region and a real external exit pupil. Or, the fold mirror can be moved into a bypass position where the incident beams bypass the primary, secondary, tertiary and quaternary mirrors and instead reflect off the fold mirror directly to the exit pupil. In an alternative embodiment, the tertiary mirror instead of the fold mirror can be moved into either the bypass position or the non-bypass position.

Abstract: The present invention provides an illumination system for varying the size of an illumination field incident to a scattering optical element. The illumination field is subsequently imaged to a reticle in a photolithographic process. The illumination system includes, in series along an optical axis of the illumination system, an optical source, a beam conditioner, a first optical integrator, a first or input collimating lens, a zoom array integrator (ZAI), a second or output collimating lens, the optical scattering element, a relay lens, and the reticle. The ZAI includes an assembly of fixed and moveable lens components arranged to vary the size of the illumination field throughout a zoom range of the ZAI while maintaining telecentric illumination at a substantially fixed numerical aperture. Illumination telecentricity and substantially fixed numerical apertures are maintained at both the scattering optical element and the reticle throughout the zoom range.

Abstract: An illumination source or condenser used to project the image of a reticle onto a photosensitive substrate used in photolithography having a first reflective fly's eye, faceted mirror, or mirror array with predeterminedly positioned facets or elements and a second reflective fly's eye, faceted mirror, or mirror array having predeterminedly positioned facets or elements for creating a desired radiant intensity, pupil fill, or angular distribution. A source of extreme ultraviolet electromagnetic radiation is provided to a first fly's eye or mirror array with arcuate shaped facets or elements. The arcuate shaped facets or elements are positioned to create an image of the source at corresponding facet in a second reflective fly's eye or mirror array. 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.

Abstract: A method and apparatus (30) for compensating for optical aberration created by a conformal window (60). The apparatus (30) comprises a one-dimensional corrector plate (32) for providing a varying amount of linear coma, first and second cylindrical lenses (34, 38) for providing a varying amount of astigmatism and a system for adjusting the corrector plate (32) and the lenses (34) and (38) to minimize the optical aberration created by the conformal window. The apparatus (30) of the present invention provides for correction of considerable amounts of optical aberration over a wide field of regard. The apparatus is simple in design, easy to install and cost effective.