POSITIONING SYSTEM, A LITHOGRAPHIC APPARATUS AND A METHOD FOR POSITIONAL CONTROL

摘要

A positioning system for controlling a relative position between a first component and a second component of a lithographic apparatus, wherein a position of each component is defined by a set of orthogonal coordinates, the positioning system including: a measuring device configured to determine an error in the momentary position of one of the components with respect to a setpoint position in a measurement coordinate; and a controller configured to control movement of the other component in a control coordinate based on the determined error; wherein the measurement coordinate is different from the control coordinate.