Lithographic apparatus and thermal optical manipulator control method

摘要

A control method is provided for controlling a heating of a thermal optical element, the thermal optical element having a matrix of heater elements. The method includes stabilizing a nominal temperature of the thermal optical element with a feedback loop to control the heating of heater elements; providing a desired temperature profile of the thermal optical element by a set point signal; determining a feedforward control of the heater elements from the set point signal; and forwardly feeding an output of the feedforward control into the feedback loop.