Patent ID: 7262831

Claim:
Lithographic projection apparatus comprising: a radiation system configured to provide a beam of radiation; a support structure configured to hold a patterning device, the patterning device capable of imparting a pattern to the beam; a substrate table configured to hold a substrate; a projection system configured to project the patterned beam onto a target portion of the substrate; a measurement system configured to measure changes in projection system aberrations with time; a predictive control system configured to predict variation of projection system aberrations with time on the basis of model parameters and to generate a control signal to compensate a time-varying property of the apparatus; an inline model identification system configured to estimate 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 configured to utilize the model parameter errors to update the model parameters of the predictive control system in order to maintain the time-varying property within acceptable performance criteria.