A new objective for EUV lithography, EUV microscopy, and 2D x-ray imaging

This paper describes a new objective for EUV lithography, EUV-microscopy, and 2D x-ray imaging, which similar to the well-known Schwarzschild objective and which consists of two concentric, convex and concave, spherical reflectors. Its essentially new feature is that it satisfies the Bragg condition for the wavelength of interest at every point on the surfaces of both reflectors. The reflectors would be spherical multi-layer structures with a uniform 2d-spacing, in the case of EUV radiation, and spherically bent crystals, in the case of x-rays. Thanks to this new feature, it is possible to obtain two-dimensional EUV or x-ray images from a large area, at once. The advantage for EUV lithography would be that an entire mask could be imaged onto a wafer, at once, and that a scanning of the mask by a narrow beam of EUV radiation – which is being used with present systems because the Bragg condition can only locally be satisfied - would no longer be necessary.