Abstract: An optical integrator having a first surface and a second surface that is used in a lithographic apparatus to modify light. The first surface is reflective, defines a volume, and is configured to be disposed in an optical illumination system along an optical axis, to surround the optical axis, and to reflect a light along a path incident upon the first surface. The second surface is disposed in the volume and has a first section of the second surface that is semi-reflective and is configured to reflect a first portion of a light along a path incident upon the first section of the second surface and to transmit a second portion of the light along the path incident upon the first section of the second surface. The second surface increases the number of reflections of the light to increase the uniformity of the intensity distribution of the light.

Abstract: An interferometric lithography system produces a pattern having a sharp field edge and minimal optical path length difference. Light passes through a beamsplitter into an input prism. The two beams produced by the beamsplitter are reflected off respective surfaces of the input prism toward a substrate prism. The substrate prism is symmetric to the input prism such that the incidence angle at an image plane is approximately equal to the beamsplitter diffraction angle. Alternatively, light passes through a beamsplitter into a prism. The two beams produced by the beamsplitter are reflected off respective surfaces of the prism toward an output surface of the prism, such that the incidence angle at the output surface is approximately equal to the beamsplitter diffraction angle. A plurality of these interferometers can be stacked, each being optimized for a given pitch, such that the stack provides a variable pitch interferometry system.

Abstract: A system and method are used to substantially homogenizing and removing at least some coherence from a beam of light.