In this paper we describe the basic principle of FlexWave, a new high resolution
wavefront manipulator, and discuss experimental data on imaging, focus and overlay.
For this we integrated the FlexWave module in a 1.35 NA immersion scanner. With
FlexWave we can perform both static and dynamic wavefront corrections. Wavefront
control with FlexWave minimizes lens aberrations under high productivity usage of the
scanner, hence maintaining overlay and focus performance, but moreover, the high
resolution wavefront tuning can be used to compensate for litho related effects.
Especially now mask 3D effects are becoming a major error component, additional
tuning is required. Optimized wavefront can be achieved with computational lithography,
by either co-optimizing source, mask, and Wavefront Target prior to tape-out, or by
tuning Wavefront Targets for specific masks and scanners after the reticle is made.