Facility for extreme ultraviolet reflectometry of lithography optics

One of the most demanding applications of optics and optical coatings is in extreme ultraviolet lithography. Optical substrates must be polished to an accuracy of less than a nanometre, both the substrate and multilayer coatings must be atomically smooth, and the coatings must have a period that is controlled to a few tens of picometres. The metrology must have even greater capabilities to assure that the strict tolerances are met. Our extreme ultraviolet reflectometry facility has recently been furnished with the addition of a sample chamber that is capable of scanning the entire surface of a mirror up to 35 cm in diameter. The capabilities of this chamber will be described, as will the performance of the monochromator. Finally a plan will be presented to increase the stability of our monochromator in order to meet the needs of future generations of lithography tools.