Synchrotron-based EUV lithography illuminator simulator

Abstract

A lithographic illuminator to illuminate a reticle to be imaged with a range of angles is provided. The illumination can be employed to generate a pattern in the pupil of the imaging system, where spatial coordinates in the pupil plane correspond to illumination angles in the reticle plane. In particular, a coherent synchrotron beamline is used along with a potentially decoherentizing holographic optical element (HOE), as an experimental EUV illuminator simulation station. The pupil fill is completely defined by a single HOE, thus the system can be easily modified to model a variety of illuminator fill patterns. Also the HOE allows the generated pupil fill pattern to be arbitrary. Because a HOE can be designed to generate any desired angular spectrum such a device can serve as the basis for an arbitrary illuminator simulator. In one embodiment of the illuminator, which is used for an optical image processing system, wherein the image processing system includes an optical system that employs an arbitrary pupil fill pattern, the illuminator device includes: (i) a source of coherent or partially coherent radiation, (ii) a holographic optical element (HOE) having a surface that receives incident radiation from said source, and (iii) a condenser optic that re-images a surface of the holographic optical element to the entrance of said image processing system. The device can be employed to generate an arbitrary pupil fill pattern in the entrance of an image processing system that includes the steps of: (a) directing incident radiation onto a surface of a holographic optical element (HOE) wherein the radiation is coherent or partially coherent radiation, and (ii) (b) re-imaging the surface of the HOE to the entrance of the image process system.

Dependencies are inferred from the claim text.