Abstract: A method for calibrating an auxiliary sensor system is provided. The auxiliary sensor system measures a position of a grating relative to a reference, the grating forming part of an encoder measurement system. The encoder measurement system is adapted to measure a position of a substrate table of a lithographic apparatus and further comprises a sensor mounted to the substrate table. The method comprises exciting the grating to make a movement in at least one measurement direction of the auxiliary sensor system, obtaining an auxiliary sensor system output signal from the sensor system during the movement, and adjusting a parameter of the auxiliary sensor system based on the output signal obtained during the movement to thereby calibrate the auxiliary sensor system.

Abstract: A position measurement system configured to measure a position quantity of a movable object in a measurement direction, the system including a radiation source, a beam splitter to split the radiation beam in a measurement beam and a reference beam, a first reflective surface mounted on the movable object to receive the measurement beam, a second reflective surface mounted on a reference object to receive the reference beam, and a detector arranged to receive a first and second reflected beam reflected by the first and second reflective surface, respectively, and configured to provide a signal representative of the position quantity of the movable object based on the first and the second beam, wherein the radiation source and detector are mounted on an object that is different from the movable object and the reference object.

Abstract: A lithographic apparatus is provided with an optical encoder measurement system having an irradiation system to direct an irradiation beam to a first scale. The system has optics to direct a primary diffracted beam diffracted from the first scale upon irradiation by the irradiation beam to a second scale and a detector to detect a secondary diffracted beam after interference and a second diffraction of the primary diffracted irradiation beam on the second scale to measure the position of the first scale with respect to the second scale.

Abstract: A lithographic apparatus is disclosed that includes an encoder type sensor system configured to measure a position of a substrate table of the lithographic apparatus relative to a reference structure. The encoder type sensor system includes an encoder sensor head and an encoder sensor target and the lithographic apparatus comprises a recess to accommodate the encoder sensor target.

Abstract: A method for calibrating an auxiliary sensor system is provided. The auxiliary sensor system measures a position of a grating relative to a reference, the grating forming part of an encoder measurement system. The encoder measurement system is adapted to measure a position of a substrate table of a lithographic apparatus and further comprises a sensor mounted to the substrate table. The method comprises exciting the grating to make a movement in at least one measurement direction of the auxiliary sensor system, obtaining an auxiliary sensor system output signal from the sensor system during the movement, and adjusting a parameter of the auxiliary sensor system based on the output signal obtained during the movement to thereby calibrate the auxiliary sensor system.