The lithography roadmap demands overlay reduction along with increased productivity. New applications are proposed
as lithography solution for the 32-nm node and possibly beyond. Most of them require very tight overlay and multiple
exposures. Major contributors in the overlay budget are coming from the exposure system, like thermal stability, lens
aberrations stability, stage positioning and alignment. An additional complexity is the interaction with the actual process
and the pattern on the reticle. To keep the lithography roadmap affordable, the cost per wafer needs to be tamed by
boosting the productivity of the exposure tool.
To enable new applications in a production environment a new generation lithographic exposure tools was developed,
with improved overlay and increased productivity. The optical column contains an improved 1.35 NA immersion lens.
Compared to the former generation the combination of overlay and productivity requirements are met by a high
acceleration wafer stage along with a new stage position measurement system, introducing new technologies paving the
way to meet the future roadmap requirements. The increased disturbances caused by the higher accelerations are
countered by a short-beam interferometer system thus ensuring optimal positioning performance. Further productivity
enhancements are reached by reducing non-exposure time.
The latest performance results will be presented; this will include overlay results as well as other critical system