Patent attributes
A lithographic apparatus is disclosed. The apparatus includes a projection optics assembly for projecting a patterned beam of radiation onto a target portion of a substrate. The assembly includes a plurality of movable optical elements and a plurality of sensor units for sensing a position and/or orientation of a respective optical element. The movable optical elements are arranged in a spaced relationship on a support frame. The support frame is at least partly formed by an assembly of at least two interconnected segments. Each of the segments movably mount at least one of the optical elements and fixedly mount at least one of the sensor units. The support frame serves as a reference and mounting frame within which the optical elements are mounted in the spaced relationship.
