Abstract:
The invention provides a wavelength tracking system comprising a wavelength tracking unit and an interferometer system. The wavelength tracking unit has reflection surfaces at stabile positions providing a first reflection path with a first path length and a second reflection path with a second path length. The first path length is substantially larger than the second path length. The interferometer system comprises: a beam splitter to split a light beam in a first measurement beam and a second measurement beam; at least one optic element to guide the first measurement beam, at least partially, along the first reflection path and the second measurement beam, at least partially, along the second reflection path; a first light sensor arranged at an end of the first reflection path to receive the first measurement beam and to provide a first sensor signal on the basis of the first measurement beam; a second light sensor arranged at an end of the second reflection path to receive the second measurement beam and to provide a second sensor signal on the basis of the second measurement beam; and a processing unit to determine a wavelength or change in wavelength on the basis of the first sensor signal and the second sensor signal.
Abstract:
An encoder includes an optical component and an enclosing device having a first surface portion and a second surface portion. The first surface portion is arranged to receive from an ambient environment a first radiation beam. The second surface portion is arranged to receive from the ambient environment a second radiation beam. The optical component is arranged to combine the first and second radiation beams. The enclosing device is arranged to propagate the first radiation beam along a first path. The first path is between the first surface portion and the optical component. The enclosing device is arranged to propagate the second radiation beam along a second path. The second path is between the second surface portion and the optical component. The enclosing device is arranged to enclose a space, so as to isolate the first path and the second path from the ambient environment.
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:
An interferometer system, including a heterodyne interferometer and a processing system. The heterodyne interferometer is arranged to provide a reference signal and a measurement signal. The reference signal has a reference phase. The measurement signal has a measurement phase and an amplitude. The processing system is arranged to determine a cyclic error of the heterodyne interferometer based on the reference phase, the measurement phase and the amplitude.
Abstract:
A lithographic apparatus includes an optical sensor, a movable body, a support, a deflector system, a first drive system and a second drive system. The movable body is moveable relative to the sensor. The support is for holding the sensor. The first drive system is arranged to move the movable body relative to the sensor. The second drive system is arranged to move the first drive system relative to the sensor. The second drive system is arranged to move the deflector system relative to the sensor. A disturbance is induced by a movement of the movable body. The deflector system is arranged to create a deflecting area for reflecting the disturbance away from the support.
Abstract:
A lithographic apparatus includes an optical sensor, a movable body, a support, a deflector system, a first drive system and a second drive system. The movable body is moveable relative to the sensor. The support is for holding the sensor. The first drive system is arranged to move the movable body relative to the sensor. The second drive system is arranged to move the first drive system relative to the sensor. The second drive system is arranged to move the deflector system relative to the sensor. A disturbance is induced by a movement of the movable body. The deflector system is arranged to create a deflecting area for reflecting the disturbance away from the support.