Demonstrate replacement without optical readjustment

Demonstrate whether degraded planar mirror facets in the modular two-mirror faceted EUV projection system can be replaced without optical readjustment while preserving alignment, phase control, and imaging performance.

Background

The faceted architecture is described as potentially allowing modular changes to the accepted numerical aperture and local replacement of degraded elements. However, because the system relies on channel-specific facet positions, angular alignment, and phase relationships, the practical possibility of replacing a facet without subsequent optical adjustment remains unresolved.