Lithographic apparatus, device manufacturing method, and device manufactured by said method

摘要

On-the-Fly leveling in a lithographic apparatus is conducted using a setpoint derived by filtering the output of the combination of the output of a level sensor and another position sensor (LVDT or IFM). The level sensor may include look-ahead. The filter may be a low pass filter to cut-off level variations of wavelength shorter than the width of the slit during a scanning exposure. The filter may also be selected to reduce cross-talk between tilt movements and horizontal displacements.