HIGH NA (NUMERICAL APERTURE) RECTANGULAR FIELD EUV CATOPTRIC PROJECTION OPTICS USING TILTED AND DECENTERED ZERNIKE POLYNOMIAL MIRROR SURFACES

摘要

A catoptric system for EUV lithography includes six freeform reflective surfaces that are specified based on fringe Zernike polynomials. Each of the surfaces is tilted and/or decentered in a meridian plane and with respect to a common axis so that image and object planes are parallel. Rectangular fields can be imaged with image space numerical aperture of at least 0.5.