Abstract: An apparatus for use in a metrology process or a lithographic process, the apparatus including: an object support module adapted to hold an object; and a first gas shower arranged on a first side of the object support module and adapted to emit a gas with a first velocity in a first gas direction which is a horizontal direction to cause a net gas flow in the apparatus to be a substantially horizontal gas flow in the first gas direction at least above the object support module.

Abstract: A stage apparatus for an e-beam inspection apparatus comprising: an object table (3) comprising an supporting surface, the object table configured to support a substrate (190) on the supporting surface; a positioning device (180) configured to a position the object table; a position measurement system (5) comprising a position sensor (8-10) configured to measure a height position of the object table parallel to a first axis, the first axis being substantially perpendicular to the supporting surface, the position sensor comprising an interferometer measurement system having an interferometer sensor (9, 10, 22), wherein a measurement beam (11, 15) of the interferometer sensor is configured to irradiate a reflective surface (13, 17) of the object table in a measurement direction, the measurement direction having a first component parallel to the first axis and a second component parallel to a second axis, the second axis being substantially perpendicular to the first axis.

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 stage apparatus for an e-beam inspection apparatus comprising: an object table (3) comprising an supporting surface, the object table configured to support a substrate (190) on the supporting surface; a positioning device (180) configured to a position the object table; a position measurement system (5) comprising a position sensor (8-10) configured to measure a height position of the object table parallel to a first axis, the first axis being substantially perpendicular to the supporting surface, the position sensor comprising an interferometer measurement system having an interferometer sensor (9, 10, 22), wherein a measurement beam (11, 15) of the interferometer sensor is configured to irradiate a reflective surface (13, 17) of the object table in a measurement direction, the measurement direction having a first component parallel to the first axis and a second component parallel to a second axis, the second axis being substantially perpendicular to the first axis.

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 lithographic apparatus is calibrated by reference to a primary reference substrate. Using an apparatus which need not be the same as the one being calibrated, there is obtained an apparatus-specific fingerprint of the primary reference substrate. Using the same set-up there is then obtained an apparatus-specific fingerprint of a secondary reference substrate. The apparatus-specific fingerprint of the primary reference substrate is subtracted from the apparatus-specific fingerprint of the secondary reference substrate to obtain and store an apparatus-independent fingerprint of the secondary reference substrate. The secondary reference substrate and stored apparatus-independent fingerprint are subsequently used together in place of the primary reference substrate as a reference for the calibration of the lithographic apparatus to be calibrated.

Abstract: A lithographic apparatus is calibrated by reference to a primary reference substrate. Using an apparatus which need not be the same as the one being calibrated, there is obtained an apparatus-specific fingerprint of the primary reference substrate. Using the same set-up there is then obtained an apparatus-specific fingerprint of a secondary reference substrate. The apparatus-specific fingerprint of the primary reference substrate is subtracted from the apparatus-specific fingerprint of the secondary reference substrate to obtain and store an apparatus-independent fingerprint of the secondary reference substrate. The secondary reference substrate and stored apparatus-independent fingerprint are subsequently used together in place of the primary reference substrate as a reference for the calibration of the lithographic apparatus to be calibrated.

Abstract: A position measurement system includes a first position measurement unit configured to measure a position of an object in a first and a second direction, the first position measurement unit including a first sensor and a first grating that extends in a first direction, a second position measurement unit configured to measure the position of the object in the first and the second direction, the second position measurement unit including a second sensor and a second grating that extends in the first direction. The position measurement system is configured to initialize the second position measurement unit based on a position measurement of the first position measurement unit.

Abstract: A lithographic apparatus is presented that includes a substrate holder configured to hold a substrate, an illuminator configured to condition a beam of radiation, a support structure configured to support a patterning device that imparts a desired pattern to the beam of radiation, a projection system that projects the patterned beam onto a target portion of the substrate, and an interferometer system configured to measure a position of the object to assist in positioning the object.

Abstract: A position measurement system for measuring a position of an object is described, the system including: a first incremental measurement unit for measuring a first number of first distance steps in a distance between a reference frame and the object, wherein the first number equals a first integer value plus a first fraction, and a second incremental measurement unit for measuring a second number of second distance steps in a distance between the reference frame and the object, wherein the second number equals a second integer value plus a second fraction, wherein the position measurement system is constructed and arranged to initialize the second incremental measurement unit on the basis of the first number and the second fraction.

Abstract: A lithographic projection apparatus including an illumination system configured to provide a beam of radiation, a support configured to support a patterning device, the patterning device configured to impart the beam with a pattern in its cross section, a substrate table configured to hold a substrate, a projection system configured to project the patterned radiation onto a target portion of the substrate, a plurality of level sensors for sensing a level of a substrate carried on the substrate table at a plurality of different positions, and a system for determining the position of the substrate table.

Abstract: In a lithographic apparatus, a measurement of the position of an object in an ambient space by an object position measuring system which is influenced by pressure variations in the ambient space, is corrected by an accurate measurement of the pressure in the ambient space. A pressure difference is measured between a pressure in a reference pressure volume and an ambient pressure in an ambient space. An absolute pressure in the reference pressure volume is added to the pressure difference to determine a change of pressure in the ambient space. Alternatively, the pressure difference is integrated over time and a determined change of pressure in the reference pressure volume is added to the pressure difference to determine a change of pressure in the ambient space.

Abstract: A lithographic apparatus includes an interferometer configured to measure a position of a mirror of the lithographic apparatus. For measuring unflatness of the mirror the interferometer includes a modulator configured to modulate a position of an input beam of the interferometer, a synchronous detector configured to synchronously detect an interfered, modulated beam, and a calculator configured to calculate an unflatness of an area of the mirror from an effect of the modulation of the position of the input beam on an output signal of the synchronous detector. The modulator can include a rotatable, tilted, plan plate.

Abstract: Measurements of an interferometric measurement system are corrected for variations of atmospheric conditions such as pressure, temperature, and turbulence using measurements from a second harmonic interferometer (SHI). A ramp, representing the dependence of the SHI data on path length, is removed before utilizing the SHI data. The SHI may include a passive Q-switched laser as a light source and Brewster prisms in the receiver module. Optical fibers may be used to conduct light to the detectors. A mirror reflecting the measurement beams has a coating of a thickness selected to minimize the sensitivity of the SHI data to changes in coating thickness.

Abstract: Measurements of an interferometric measurement system are corrected for variations of atmospheric conditions such as pressure, temperature, and turbulence using measurements from a second harmonic interferometer (SHI). A ramp, representing the dependence of the SHI data on path length, is removed before utilizing the SHI data. The SHI may include a passive Q-switched laser as a light source and Brewster prisms in the receiver module. Optical fibers may be used to conduct light to the detectors. A mirror reflecting the measurement beams has a coating of a thickness selected to minimize the sensitivity of the SHI data to changes in coating thickness.

Abstract: Measurements of an interferometric measurement system are corrected for variations of atmospheric conditions such as pressure, temperature, and turbulence using measurements from a second harmonic interferometer (SHI). A ramp, representing the dependence of the SHI data on path length, is removed before utilizing the SHI data. The SHI may include a passive Q-switched laser as a light source and Brewster prisms in the receiver module. Optical fibers may be used to conduct light to the detectors. A mirror reflecting the measurement beams has a coating of a thickness selected to minimize the sensitivity of the SHI data to changes in coating thickness.

Abstract: A lithographic projection apparatus which uses one, and optionally also two or more color interferometric devices to accurately determine the position of a movable table within the apparatus. The apparatus comprises a purge gas source to supply purge gas to a space accommodating at least a part of said movable table, the purge gas being selected such that leakage of the purge gas into the area of operation of the interferometric devices does not cause significant error in the interferometric measurements.

Abstract: A lithographic projection apparatus which uses one, and optionally also two or more color interferometric devices to accurately determine the position of a movable table within the apparatus. The apparatus comprises a purge gas source to supply purge gas to a space accommodating at least a part of said movable table, the purge gas being selected such that leakage of the purge gas into the area of operation of the interferometric devices does not cause significant error in the interferometric measurements.