Abstract: A radiation system to generate a radiation emitting plasma, the radiation system include a fuel emitter to provide a fuel target at a plasma formation region, a first laser arranged to provide a first laser beam at the plasma formation region incident on the fuel target to generate a radiation emitting plasma, an imaging device arranged to obtain a first image of the radiation emitting plasma at the plasma formation region, the first image indicating at least one image property of the radiation emitting plasma, and a controller. The controller is arranged to receive the first image, and to generate at least one instruction based on the at least one image property of the radiation emitting plasma to modify operation of at least one component of the radiation system to reduce a detrimental effect of debris.

Abstract: A radiation system to generate a radiation emitting plasma, the radiation system include a fuel emitter to provide a fuel target at a plasma formation region, a first laser arranged to provide a first laser beam at the plasma formation region incident on the fuel target to generate a radiation emitting plasma, an imaging device arranged to obtain a first image of the radiation emitting plasma at the plasma formation region, the first image indicating at least one image property of the radiation emitting plasma, and a controller. The controller is arranged to receive the first image, and to generate at least one instruction based on the at least one image property of the radiation emitting plasma to modify operation of at least one component of the radiation system to reduce a detrimental effect of debris.

Abstract: An EUV radiation source in the form of a plasma is focused at a virtual source point so as to pass through an exit aperture of a source collector module in an EUV lithographic apparatus. Plasma position is controlled in three directions, X, Y and Z using monitoring signals. By exploiting the photoacoustic effect, the monitoring is accomplished in a non-intrusive manner using acoustic sensors coupled to material of a cone which surrounds the exit aperture. Different angular positions of the radiation beam can be deduced by discriminating signals from the different sensors on the basis of relative arrival time or phase, and/or by comparing the amplitude/intensity of the signals. A sequencer function can be used to introduce a sequence of deliberate offsets in the beam position. This allows acoustic signals to be generated and detected for measurement purposes, when the beam would otherwise not impinge on the material.

Abstract: A method of exposing a substrate (e.g. in a lithographic apparatus comprising a substrate table to support a substrate) according to one embodiment of the invention includes performing first and a second height measurement of a part of at least one substrate with a first and second sensor, generating and storing an offset error map based on a difference between the measurements; generating and storing a height map of portions of the substrate (or another substrate that has had a similar processing as the part) by performing height measurements with the first sensor and correcting this height map by means of the offset error map; and exposing the substrate (or the other substrate).

Abstract: A level sensor for determining a height of a substrate. In one configuration, the level sensor forms part of a lithographic apparatus that includes a projection lens system. The level sensor generates one or more measurement beams and directs the measurement beam to a measurement spot on a substrate having a first reflecting surface, and produces a reflected measurement beam. The level sensor also generates one or more reference beams. A detector detects both the reflected measurement beam and the reference beam, respectively, and produces a measurement signal and a reference signal, respectively, the measurement signal being indicative for the height at the measurement spot. A processor that receives these signals and corrects the measurement signal based on the reference signal.

Abstract: A lithographic apparatus is disclosed. The apparatus includes a substrate table constructed to hold a substrate. The substrate table is moveable to transfer the substrate between a substrate measuring position and a substrate processing position. The apparatus also includes a measuring system configured to measure at least one aspect or characteristic of the substrate when the substrate table holds the substrate in the measuring position. The measuring system is configured to direct at least one measuring beam and/or field towards a surface of the substrate. A projection system is configured to project a patterned radiation beam onto a target portion of the substrate when the substrate table holds the substrate in the substrate processing position, and a conditioning system is configured to supply a conditioning fluid to at least part of a path of the measuring beam and/or field of the measuring system to condition the part of the path.

Abstract: The invention relates to a level sensor for determining a height of a substrate. The level sensor generates one or more measurement beam and directs the measurement beam to a measurement spot on the substrate and produces a reflected measurement beam. The level sensor also generates one or more reference beams. A detector detects both the reflected measurement beam and the reference beam, respectively, and produces a measurement signal and a reference signal, respectively, the measurement signal being indicative for the height at the measurement spot. A processor that receives these signals and corrects the measurement signal based on the reference signal. The level sensor has an optical arrangement in a predetermined area close to where the substrate is to be located. The measurement beam and the reference beam propagate along substantially equal optical paths of propagation in the predetermined area.

Abstract: The invention relates to a level sensor for determining a height of a substrate. The level sensor generates one or more measurement beam and directs the measurement beam to a measurement spot on the substrate and produces a reflected measurement beam. The level sensor also generates one or more reference beams. A detector detects both the reflected measurement beam and the reference beam, respectively, and produces a measurement signal and a reference signal, respectively, the measurement signal being indicative for the height at the measurement spot. A processor that receives these signals and corrects the measurement signal based on the reference signal. The level sensor has an optical arrangement in a predetermined area close to where the substrate is to be located. The measurement beam and the reference beam propagate along substantially equal optical paths of propagation in the predetermined area.