Abstract
IC manufacturers have a strong demand for transferring a working process from one scanner to another. Recently, a
programmable illuminator (FlexRayTM) became available on ASML ArF immersion scanners that, besides all the
parameterized source shapes of the earlier AerialTM illuminator (based on diffractive optical elements) can also produce
any desired freeform source shape. As a consequence, a fabrication environment may have scanners with each of the
illuminator types so both FlexRay-to-Aerial and FlexRay-to-FlexRay matching is of interest. Moreover, the FlexRay
illuminator itself is interesting from a matching point-of-view, as numerous degrees of freedom are added to the
matching tuning space.
This paper demonstrates how the upgrade of an exposure tool from Aerial to FlexRay illuminator shows identical
proximity behavior without any need for scanner tuning. Also, an assessment of the imaging correspondence between
exposure tools each equipped with a FlexRay illuminator is made. Finally, for a series of use-cases where proximity
differences do exist, the application of FlexRay source tuning is demonstrated. It shows an enhancement of the scanner
matching capabilities, because FlexRay source tuning enables matching where traditional NA and sigma tuning are
shortcoming. Moreover, it enables tuning of freeform sources where sigma tuning is not relevant. Pattern MatcherTM
software of ASML Brion is demonstrated for the calculation of the optimized FlexRay tuned sources.
