Patent ID: 7474378

Claim:
A lithographic apparatus comprising: an illumination system for providing a beam of radiation; a support structure for supporting a patterning device, the patterning device serving to impart the beam of radiation with a pattern in its cross-section; a substrate table for holding a substrate; and a projection optics assembly for projecting the patterned beam onto a target portion of the substrate, said assembly comprising: a first element comprising a sensor having a predetermined functionality that is positioned with respect to a second element in a spaced relationship on a support frame, said support frame having an interface surface formed on or in said support frame for receiving said first element; and an interfacing element disposed between said interface surface and said first element, wherein said interface surface determines the position of said first element with respect to said second element, and is configured in accordance with said predetermined functionality so that said first element is positionable with respect to said second element with at least three degrees of freedom.