Abstract

We are doing physical optics modeling of soft-x-ray projection lithography experiments; the wavelength is 14 nm, and the desired feature size on the wafer is 100 nm. The projection optics consist of an off-axis, two-mirror Schwarzschild operating at f/5. The condenser optics are arranged in Köhler geometry for two different x-ray source types. An off-axis elliptical mirror is used to image an x-ray plasma source into the entrance pupil of the Schwarzschild. The other source is an XUV undulator storage ring. Its output radiation is brought to a focus in the entrance pupil and then scanned in a circle. We change the geometries to vary the amount of partial coherence. We also examine the effects of aberrations in the condenser.

© 1992 Optical Society of America