Current status of EUV optics and future advancements in optical components

An essential component for the success of extreme ultraviolet lithography is realization of an all-reflective optical imaging system with a total wavefront error approaching 0.25 nm rms and total flare of 5-10%. The current thinking in the EUVL community is to produce beta-class tools with a numerical aperture of about 0.25 and operate them at an EUV wavelength of about 13 nm. If a system with these parameters and wavefront quality can be achieved, then an EWL camera will print lithographic-quality features with 30 nm dense lines and spaces. While no such system has been assembled to date, all the prototype systems fabricated thus far indicate that the final goal will be reached within the next one- to two-years. While the final success of EUVL depends on many factors beyond the optical system, this paper will concentrate on EUVL imaging optical components and the technologies necessary to support their commercial manufacture and use.