摘要:
An improved lithographic interferometer system, is presented herein. The lithographic interferometer system comprises a beam generating mechanism, mirrors which reflect those beams, and detection devices for detecting an interference pattern of overlapping reflected beams. The beam generating mechanism comprises a beam-splitter, which splits the beams into reference beams and measuring beams, a reference mirror that provides a plane mirror interferometer, and a reflective surface that emits at least one reference beam used in a differential plane mirror interferometer.
摘要:
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.
摘要:
A lithographic apparatus includes a radiation source configured to provide radiation to an illumination system, the radiation source configured to provide radiation in a first wavelength range and in a second wavelength range, the second wavelength range being different from the first wavelength range. A support is configured to support a patterning device, the patterning device is configured to impart the radiation with a pattern in its cross-section. A substrate table is configured to hold a substrate, and a projection system is configured to project the patterned radiation onto a target portion of a substrate. The first wavelength range is the primary wavelength of the lithographic apparatus. The second wavelength range is used for setup of the lithographic apparatus, the setup including one or more of calibration, qualification, performance test, and alignment. The second wavelength range may also be used for exposure of a further substrate.
摘要:
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.
摘要:
An encoder-type measurement system is configured to measure a position dependent signal of a movable object, the measurement system including at least one sensor mountable on the movable object a sensor target object mountable on a substantially stationary frame, and a mounting device configured to mount the sensor target object on the substantially stationary frame. The measurement system further includes a compensation device configured to compensate movements and/or deformations of the sensor target object with respect to the substantially stationary frame. The compensation device may include a passive or an active damping device and/or a feedback position control system. In an alternative embodiment, the compensation device includes a gripping device which fixes the position of the sensor target object during a high accuracy movement of the movable object.
摘要:
A position measurement system to measure a position of a movable stage includes a reference plate; a plurality of sensors arranged such that, depending on a position of the movable stage relative to the reference plate, at least a subset of the plurality of sensors is configured to cooperate with the reference plate to provide for each of the sensors in the subset respective sensor signals representative of a position of the respective sensor relative to the reference plate; and a processor arranged to determine from the sensor signals a stage position, the processing device configured so as to, when the stage is in a position where an over-determined number of sensor signals is provided by at least the subset of the sensors that are in operational cooperation with the reference plate, (a) determine the stage position from a subset of the over-determined number of sensor signals, and (b) correct a sensor signal of one or more of the sensors from a discrepancy between the determined stage position and a remainder of the sensors signals.
摘要:
A stage system includes a movable stage, at least two encoder heads each constructed to provide an encoder signal representative of a position of the movable stage with respect to an encoder target structure, and a controller to control a position of the stage. The controller is provided with the encoder signals of each of the encoder heads. The controller is arranged to apply a weighting function to the encoder signals and to derive a position of the stage from the weighted encoder signals.
摘要:
The present invention relates to a method for calibrating a grating of an encoder measurement system between two adjacent calibrated locations, the method includes moving one of a sensor object including an encoder-type sensor and a grating along the other one of the sensor object and the grating with a speed, wherein the speed is selected such that disturbances in the grating substantially extending over a distance smaller than a distance between the two calibrated locations can not or only partly be followed by the one of the sensor object and the grating, and measuring during the moving the position of the sensor object with respect to the grating at a plurality of locations between the two calibrated locations.
摘要:
A measurement unit to determine a position in a first and second dimension includes a diffraction type encoder and an interferometer. The diffraction type encoder determines by means of a diffraction on a first and a second diffraction grating the position in the first dimension of the second grating with respect to the first grating, The interferometer determines the position in the second dimension of a mirror. The measurement unit includes a combined optical unit to transfer an encoder measurement beam as well as an interferometer measurement beam. Further, the measurement unit may include a combined light source for the encoder as well as the interferometer. One of the first and second diffraction gratings may further show some degree of zero order reflection to provide the mirror of the interferometer.
摘要:
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.