Environmental data from the Engineering Test Stand

The EUV Engineering Test Stand (ETS) has demonstrated the printing of 100 nm resolution scanned images. This milestone was achieved with the ETS operating in an initial low-power configuration using a 40 W laser combined with a Xe clusterjet. The third condenser component is referred to as "C3, of which there are six individual optics. The first set of "C3" Illuminator optics was removed after this low-power operation, and extensively characterized for EUV-induced contamination. EUV reflectivity data indicate a decrease in reflectivity from an initial 66% to similar to48-56% (depending on location), with the more intensely illuminated areas of the C3 having the smaller final reflectivity. Auger electron spectroscopy indicated the observed reflectivity decrease can be largely attributed to carbon contamination, similar to 150-300Angstrom thick depending on location. No evidence was found for optic oxidation, indicating EtOH successfully prevented EUV/H2O oxidation of the outermost Si layer during exposure to both EUV and out-of-band radiation. Measurements of the reflectivity centroid wavelength showed a negligible change, suggesting the observed variations were due to surface contamination and not bulk multilayer radiation damage. The carbon contamination could be removed by RF-O-2 cleaning.