Patent ID: 6084673
Filing Date: 2000-07-04
Classification: G03F

Abstract:
A lithographic projection apparatus for step-and-scan imaging of a mask pattern present in a mask, each time on a different area of a substrate provided with a radiation-sensitive layer, said apparatus, viewed in the direction of a projection beam, successively comprising:a radiation system supplying a projection beam whose cross-section in the plane of the mask is smaller than the mask pattern;a mask table being movable in at least a first direction, the scan direction, and provided with a mask holder in which the mask can be fixed;a projection system constructed and arranged to image the irradiated part of the mask pattern on the substrate with a magnification M;a substrate table which is movable in the first direction and in a second direction perpendicular thereto and is provided with a substrate holder in which the substrate can be fixed;a mask table drive unit constructed and arranged to move the mask table during each imaging operation in at least the scan direction with respect to the projection beam and the projection system;a substrate table drive unit constructed and arranged to move the substrate table during each imaging operation in at least the scan direction at a rate which is equal to M times a rate at which the mask is moved, anda first and a second interferometer system constructed and arranged to measure during each imaging operation, the mutual position of the mask and the substrate, wherein the measuring mirrors of the interferometer systems are constituted by reflecting side faces of the mask holder and the substrate holder, respectively.