Patent Document ID: 20060114437
Application ID: 11000507
Patent Flag: 0

Claim One:
1. Lithographic projection apparatus comprising: a radiation system for providing a projection beam of radiation; a support structure for supporting a patterning device for imparting a pattern to the projection beam; a substrate table for holding a substrate; a projection system for projecting the patterned beam onto a target portion of the substrate so as to produce an image of the patterning means on the target portion; a measurement system for measuring changes in projection system aberrations with time; a predictive control system for predicting variation of projection system aberrations with time on the basis of model parameters and for generating a control signal for compensating a time-varying property of the apparatus; an inline model identification system for estimating model parameter errors on the basis of projection system aberration values provided by the predictive control system and measured projection system aberration values provided by the measurement system; and an updating system utilising the model parameter errors for updating the model parameters of the predictive control system in order to maintain the time-varying property within acceptable performance criteria.