Optimization of the optics matching a storage ring to an X-ray lithography camera

An oscillating grazing incidence mirror can be used to achieve vertically uniform illumination with a synchrotron radiation source. To increase the intensity it has been suggested previously to use a figured mirror rather than a plane mirror so that light from a larger horizontal angle can be directed into the exposure area. This paper presents results of ray-tracing calculations that show how much the intensity can actually be increased while maintaining good horizontal uniformity. Cylindrical, parabolic and elliptical mirrors are investigated and geometrical parameters are optimized. It is shown further that with an ellipsoid the throughput of a step-and-repeat camera is almost independent of the exposure field size. The parameters of the IBM X-ray lithography beamline are discussed. © 1984 SPIE.