Abstract

This condenser couples a small, incoherent source into the 60° ring-field of a camera designed for projection lithography. Quasi-Köhler illumination uniformly illuminates the whole field and a degree of partial coherence is achieved (σ≈0.8). This design was conceived with a soft-X-ray laser-plasma source in mind; hence, it is all reflective. However, it would also be suitable for any other lithographic system employing a small, bright source.

© 1993 Optical Society of America