Slit-Mask Handler

The slit mask handler carries a cassette of up to 6 masks. The cassette is removable for loading a full set of masks, or masks can be added and removed individually from the cassette when installed. A motion stage positions the cassette in front of a transfer mechanism, which removes a mask from the cassette and carries it to the focal surface. Kinematic holding fixtures locate the mask repeatably to $\pm 25 \mu$m (0.001'') in all directions at the focal surface.