With the commercialization of extreme ultraviolet (EUV) lithography underway, there is
considerable effort underway to improve EUV photoresists, so that they can meet the ITRS 2006 update
requirements for resolution, line edge roughness and sensitivity. Nevertheless, the present limited
availability of EUV exposure tools, and the high cost of such tools, has hampered the resist development
effort. We have developed a simple, low-cost, technique to characterize different photoresist formulations
for printing sub-100-nm features using EUV radiation. In the method presented here, a transmission mask
is placed in close proximity to the resist sample and the resist is exposed through the mask. The mask used
for this technique is a silicon nitride membrane with 50 nm gold layer which is patterned using a focused
ion beam tool. The source for EUV light is a xenon based discharge plasma source from Energetiq. After
developing, the resist images are measured in a scanning electron microscope to determine the feature size.
Here we present results demonstrating sub-100 nm feature size using this method.