ASML Holding N.V.
Lithographic apparatus and an object positioning system

Abstract:

A lithographic apparatus .[.comprising.]. .Iadd.includes .Iaddend.an object table .[.which carries an object.].. The lithographic apparatus may further .[.comprise at least one.]. .Iadd.include a .Iaddend.sensor .[.as part of a measurement system.]. to measure a characteristic of the object table, the environment surrounding the lithographic apparatus or another component of the lithographic apparatus. The measured characteristic may be used to estimate .[.the.]. .Iadd.a .Iaddend.deformation of .[.the.]. .Iadd.an .Iaddend.object due to .Iadd.a .Iaddend.varying .[.loads.]. .Iadd.load .Iaddend.during operation of the lithographic apparatus, for example .Iadd.a .Iaddend.varying .[.loads.]. .Iadd.load .Iaddend.induced by a two-phase flow in a channel formed .[.within.]. .Iadd.of .Iaddend.the object table. .[.Additionally, or alternatively, the.]. .Iadd.The .Iaddend.lithographic apparatus .[.comprises.]. .Iadd.may include .Iaddend.a predictor to estimate the deformation of the object based on a model. The positioning of the object table carrying the object can be controlled based on the estimated deformation. The positioning of a projection beam, used to .Iadd.provide a .Iaddend.pattern .[.a substrate.]., can be controlled relative to the object, to alter the position of the pattern and/or the projection beam on the substrate, based on the estimated deformation.