Design of beamline optics for large-field exposure

New mirror designs for an X-ray lithography (XRL) beamline have been devise d for the large-field, high-power irradiation of wafers. In contrast to ana lytically described mirrors, such as toroids, ellipsoids, etc., the new sha pes were numerically determined. The design method employed was developed b y Xiao, et al. A beamline employing such an optimized mirror design should provide a high X-ray power density of 58 mWV/cm(2) over a 50-mm-square expo sure area, and 88 mW/cm(2) over a 40-mm-square exposure area, with a unifor mity of better than +/-2%. The slope error margin was also estimated using numerical simulations, and it was found that the exposure characteristics d o not degrade when the slope error is less than 25 arcsecs over the whole s urface of the mirror.