We shipped a small field exposure tool (SFET) to Selete (Semiconductor Leading Edge Technologies, Japanese
Consortium) in 2006. The SFET was founded for the purpose of EUVL mask and resist development. We have been
working on the exposure test and the tool evaluation in collaboration with Selete.
In the development of the SFET, We have experienced to connect two types of light source to the SFET, LPP light
source and DPP light source. And now we operate the SFET with DPP light source. On exchanging light source for DPP
light source from LPP light source, we planed to apply the new illuminator unit optimized for DPP light source. The new
illuminator unit of the SFET will improve dose uniformity on the imaging surface. We have installed the new illuminator
unit of the SFET at Selete in 2007, and evaluated the effects of dose uniformity.
In EUV lithography, the system performance reflects sensitively to the exposure results. We have been evaluating the
SFET quantitatively on mainly sensitive factors, in the system performance, to exposure result. We try to take a
correlation between the system performance and exposure results. In the system performance, the synchronization error
between the wafer and mask stages is one of the main factors to exposure sensitivity. We continue to evaluate the
relations between the system performance and the exposure results.