Independently controllable shutters and variable area apertures for off axis illumination

摘要

Apertures to vary the size and shape of the aperture area without the need to change the whole aperture plate in off axis lithography. The off axis illumination apertures allow the size and shape of apertures to be changed without having to change the aperture plates for each step in the lithographic process. The aperture plate (40) is fitted with simple shutter mechanisms (41-44) that allow ready adjustment of the aperture openings.