Abstract: A method for calibrating a mirror of an interferometer system configured to measure a position of an object using two interferometers of the interferometer system that are arranged at opposite sides of the object and configured to measure the position of the object in the same X-direction, wherein two sets of measurements are obtained for different rotational orientations about an axis perpendicular to the X-direction to determine a shape of the mirror. There is also provided a position measuring method in which the obtained shape of the mirror is used to adjust measurements in the X-direction, a lithographic apparatus and a device manufacturing method making use of such a lithographic apparatus.

Abstract: A position measurement system including a first interferometer and a second interferometer arranged to determine a distance of the object in a first direction when the object is in a first measurement area by emitting beams onto a target surface of the object. The position measurement system further has a third interferometer and a fourth interferometer arranged to determine a distance of the object in the first direction when the object is in a second measurement area by emitting beams onto the target surface of the object. An arrangement of relative positions in a second direction of beams spots impinging on the target surface from the beams emitted by the first and second interferometers is different from an arrangement of relative positions in the second direction of beams spots impinging on the target surface from the beams emitted by the third and fourth interferometers.

Abstract: A method for calibrating a mirror of an interferometer system configured to measure a position of an object using two interferometers of the interferometer system that are arranged at opposite sides of the object and configured to measure the position of the object in the same X-direction, wherein two sets of measurements are obtained for different rotational orientations about an axis perpendicular to the X-direction to determine a shape of the mirror. There is also provided a position measuring method in which the obtained shape of the mirror is used to adjust measurements in the X-direction, a lithographic apparatus and a device manufacturing method making use of such a lithographic apparatus.

Abstract: A position measurement system including a first interferometer and a second interferometer arranged to determine a distance of the object in a first direction when the object is in a first measurement area by emitting beams onto a target surface of the object. The position measurement system further has a third interferometer and a fourth interferometer arranged to determine a distance of the object in the first direction when the object is in a second measurement area by emitting beams onto the target surface of the object. An arrangement of relative positions in a second direction of beams spots impinging on the target surface from the beams emitted by the first and second interferometers is different from an arrangement of relative positions in the second direction of beams spots impinging on the target surface from the beams emitted by the third and fourth interferometers.

Abstract: A positioning system for positioning an object in a lithographic apparatus, including: a first and second object tables moveable in an operating area; a first position measurement system to provide an incremental position measurement of the second object table relative to a reference when in the operating area, wherein the first position measurement system is configured to provide an absolute position measurement of the first object table relative to the reference; a second position measurement system to provide an absolute position measurement of the first object table relative to the second object table, and wherein the first position measurement system is further configured to provide an absolute position measurement of the second object table relative to the reference based on the absolute position measurement of the first object table relative to the reference and on the absolute position measurement of the first object table relative to the second object table.

Abstract: A positioning system for positioning an object in a lithographic apparatus, including: a first and second object tables moveable in an operating area; a first position measurement system to provide an incremental position measurement of the second object table relative to a reference when in the operating area, wherein the first position measurement system is configured to provide an absolute position measurement of the first object table relative to the reference; a second position measurement system to provide an absolute position measurement of the first object table relative to the second object table, and wherein the first position measurement system is further configured to provide an absolute position measurement of the second object table relative to the reference based on the absolute position measurement of the first object table relative to the reference and on the absolute position measurement of the first object table relative to the second object table.

Abstract: Method to calibrate a substrate table position in a lithographic apparatus includes providing a substrate on the substrate table with a two dimensional arrangement of patterns; positioning the substrate table with a positioning system; measuring positions of the substrate table in at least two dimensions with a position measurement system; reading out the arrangement of patterns as a function of the measured positions of the substrate table with a pattern read out system to obtain pattern read out results; deriving position errors as a function of the measured positions of the substrate table compared with the pattern read out results; calibrating the positioning system using the position errors, the calibrating including determining drift influences of the positioning system, correcting the position errors as a function of the corresponding two dimensional position of the substrate table with the determined drift influences, and calibrating the positioning system with the corrected position errors.

Abstract: Method to calibrate a substrate table position in a lithographic apparatus includes providing a substrate on the substrate table with a two dimensional arrangement of patterns; positioning the substrate table with a positioning system; measuring positions of the substrate table in at least two dimensions with a position measurement system; reading out the arrangement of patterns as a function of the measured positions of the substrate table with a pattern read out system to obtain pattern read out results; deriving position errors as a function of the measured positions of the substrate table compared with the pattern read out results; calibrating the positioning system using the position errors, the calibrating including determining drift influences of the positioning system, correcting the position errors as a function of the corresponding two dimensional position of the substrate table with the determined drift influences, and calibrating the positioning system with the corrected position errors.

Abstract: Method to calibrate a substrate table position in a lithographic apparatus includes providing a substrate on the substrate table with a two dimensional arrangement of patterns; positioning the substrate table with a positioning system; measuring positions of the substrate table in at least two dimensions with a position measurement system; reading out the arrangement of patterns as a function of the measured positions of the substrate table with a pattern read out system to obtain pattern read out results; deriving position errors as a function of the measured positions of the substrate table compared with the pattern read out results; calibrating the positioning system using the position errors, the calibrating including determining drift influences of the positioning system, correcting the position errors as a function of the corresponding two dimensional position of the substrate table with the determined drift influences, and calibrating the positioning system with the corrected position errors.

Abstract: A device manufacturing method includes projecting a patterned beam of radiation onto a substrate, wherein the position of a movable object is determined in a number of degrees of freedom using a number of sensors, the number of sensors being larger than the number of degrees of freedom, wherein the position of the movable object in the number of degrees of freedom is determined using signals of each of the sensors, wherein the signals of the sensors are weighed on the basis of the difference between noise levels of each of the sensors. Accuracy of the position measurement of movable object and/or overlay and focus performance are improved in lithographic apparatus.

Abstract: Method to calibrate a substrate table position in a lithographic apparatus includes providing a substrate on the substrate table with a two dimensional arrangement of patterns; positioning the substrate table with a positioning system; measuring positions of the substrate table in at least two dimensions with a position measurement system; reading out the arrangement of patterns as a function of the measured positions of the substrate table with a pattern read out system to obtain pattern read out results; deriving position errors as a function of the measured positions of the substrate table compared with the pattern read out results; calibrating the positioning system using the position errors, the calibrating including determining drift influences of the positioning system, correcting the position errors as a function of the corresponding two dimensional position of the substrate table with the determined drift influences, and calibrating the positioning system with the corrected position errors.

Abstract: In an interferometric displacement measuring system, a correction for beamshear is made. The correction may be a polynomial of a variable proportional to the length of the optical path traversed by the measurement beam and the angle of the measurement mirror. The correction compensates for errors caused by non-planarity of the wavefront of the measurement beam.

Abstract: A lithographic apparatus includes an object support configured to support an object. The apparatus further includes X, Y and Z interferometer measurement systems, and an object support positioning system configured to position the object support in a number of degrees of freedom on the basis of measurements of the interferometer measurement systems. A calibration device is configured to measure Ry of the object support with the X interferometer measurement system in at least two different Z positions, measure Ry of the object support with the Z interferometer measurement system in at least two different Z positions, calibrate a linear Z dependency of Ry on the basis of the measurements, and calibrating a linear X dependency of Z on the basis of the previous calibration. Similarly, a linear Y dependency of Z is calibrated.

Abstract: A method of calibration according to one embodiment includes moving a table to a plurality of exposure positions. At each position, a first part of a measurement system measures a position of the table along each of two orthogonal axes in the plane, and a mark is exposed onto the substrate. For each mark, and for two different orientations of the substrate, a second part of the measurement system measures measurement positions of the table corresponding to the mark. Based on the measured positions, a characterization of a position measurement error of the measurement system along one of the orthogonal axes, as a function of position along both of the orthogonal axes, is obtained.