Patent ID: 7847919

Claim:
A lithographic apparatus comprising: an illumination system configured to condition a radiation beam; a patterning support constructed and arranged to hold a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam; a substrate support constructed and arranged to hold a substrate; a projection system constructed and arranged to project the patterned radiation beam onto a target portion of the substrate; a first driving device constructed and arranged to move an optical component of the lithographic apparatus; a second driving device constructed and arranged to move the substrate support so as to be synchronous with the motion of the optical component; a first position measuring device constructed and arranged to provide a momentary position of the optical component; a second position measuring device constructed and arranged to provide a momentary position of the substrate support at a first sampling rate; an optical component position comparator constructed and arranged to compare the measured momentary position of the optical component with a desired momentary position of the optical component to generate an optical component position error signal in accordance with a difference between the two optical component positions; a substrate support position comparator constructed and arranged to compare the measured momentary position of the substrate support with a desired momentary position of the substrate support to generate a substrate support position error signal in accordance with a difference between the two substrate support positions; and a correcting device constructed and arranged to adjust the momentary position of the optical component so as to compensate for the difference between the two substrate support positions, the correcting device constructed and arranged to: add a position error signal, generated from the substrate support position error signal, to the optical component position error signal; add a force to the optical component creating a motion to match the addition of the position error signal to the optical component position error signal, wherein: at substantially non-constant velocity of the substrate support, the force is generated from the substrate support position error signal; and at substantially constant velocity of the substrate support, the force is generated from the momentary position provided by the second position measuring device at a second sampling rate higher than the first sampling rate.