Journal of Vacuum Science & Technology B, Vol.14, No.6, 3706-3708, 1996
Precision Optical Aspheres for Extreme-Ultraviolet Lithography
We have demonstrated significant advances in the production of aspheric optics for extreme ultraviolet lithography. An optic has been fabricated with an aspheric departure of 1.5 mu m, a figure error of 0.7 nm rms, and a nanoroughness of 0.25 nm rms. Further improvements are required in the figure and nanoroughness to reach high throughput and near diffraction limited performance in an extreme ultraviolet lithography system.