Abstract: A supercontinuum radiation source comprises: a radiation source, an optical amplifier and a non-linear optical medium. The radiation source is operable to produce a pulsed radiation beam. The optical amplifier is configured to receive the pulsed radiation beam and increase an intensity of the pulsed radiation beam. The non-linear optical medium is configured to receive the amplified pulsed radiation beam and to broaden its spectrum so as to generate a supercontinuum radiation beam. The optical amplifier may supply a pump radiation beam to a gain medium, an intensity of the pump radiation beam being periodic and having a pump frequency that is an integer multiple of the frequency of the pulsed radiation beam. The optical amplifier may supply pump energy to a gain medium only when the pulses of the pulsed radiation beam propagate through the gain medium.

Abstract: A method to improve a lithographic process of processing a portion of a design layout onto a substrate using a lithographic apparatus, the method including: adjusting a first processing parameter among processing parameters of the lithographic process to cause the processing to be more tolerant to perturbations of at least one of the processing parameters during processing; and adjusting a second processing parameter among processing parameters of the lithographic process to cause the processing to be more tolerant to perturbations of at least one of the processing parameters during processing.

Abstract: A lithographic apparatus including a support to support a patterning device, a substrate table to hold a substrate, and a projection system to project a radiation beam patterned by the patterning device onto a target portion of the substrate. A transparent layer is provided to protect the pattering device. The apparatus further includes a transparent layer deformation-determining device to determine a deformation profile of the transparent layer, the deformation profile of the transparent layer expressing a deformation of the transparent layer during a scanning movement of the lithographic apparatus, and a compensator device which is configured to control the projection system, the substrate table and/or the support in response to the deformation profile of the transparent layer to compensate for the deformation of the transparent layer during the scanning movement of the apparatus.

Abstract: A radiation source for a lithographic apparatus, in particular a laser-produced plasma source includes a fan unit surrounding but not obstructing the collected radiation beam that is operated to generate a flow in a buffer gas away from the optical axis. The fan unit can include a plurality of flat or curved blades generally parallel to the optical axis and driven to rotate about the optical axis.

Abstract: A method to improve a lithographic process for imaging a portion of a design layout onto a substrate using a lithographic projection apparatus having an illumination system and projection optics, the method including: obtaining an illumination source shape and a mask defocus value; optimizing a dose of the lithographic process; and optimizing the portion of the design layout for each of a plurality of slit positions of the illumination source.

Abstract: In an inspection apparatus, a target on the surface is illuminated with illuminating radiation that comprises first and second illuminating components. The illuminating components form one or more periodic illuminating patterns on the surface. A plurality of scattered radiation patterns formed by the illuminating radiation after scattering by the target is captured at a detector for a number of values of a controllable characteristic of at least one of the illuminating components. The captured radiation is then used to reconstruct data describing the target.

Abstract: Methods of determining a value of a parameter of interest are disclosed. In one arrangement, a symmetric component and an asymmetric component of a detected pupil representation from illuminating a target are derived. A first metric characterizing the symmetric component and a second metric characterizing the asymmetric component vary non-monotonically as a function of the parameter of interest over a reference range of values of the parameter of interest. A combination of the derived symmetric component and the derived asymmetric component are used to identify a correct value from a plurality of candidate values of the parameter of interest.

Abstract: A method of reducing effects of reticle heating and/or cooling in a lithographic process, the method including calibrating a linear time invariant reticle heating model using a system identification method; predicting distortions of the reticle using the reticle heating model and inputs in the lithographic process; and calculating and applying a correction in the lithographic process on the basis of the predicted distortions of the reticle.

Abstract: An immersion lithographic projection apparatus is disclosed in which liquid is provided between a projection system of the apparatus and a substrate. The use of both liquidphobic and liquidphilic layers on various elements of the apparatus is provided to help prevent formation of bubbles in the liquid and to help reduce residue on the elements after being in contact with the liquid.

Abstract: A patterning device comprising a reflective marker, wherein the marker comprises: a plurality of reflective regions configured to preferentially reflect radiation having a given wavelength; and a plurality of absorbing regions configured to preferentially absorb radiation having the given wavelength; wherein the absorbing and reflective regions are arranged to form a patterned radiation beam reflected from the marker when illuminated with radiation, and wherein the reflective regions comprise a roughened reflective surface, the roughened reflective surface being configured to diffuse radiation reflected from the reflective regions, and wherein the roughened reflective surface has a root mean squared roughness of about an eighth of the given wavelength or more.

Abstract: A deoxidation system for purifying target material for an EUV light source includes a furnace having a central region and a heater for heating the central region in a uniform manner. A vessel is inserted in the central region of the furnace, and a crucible is disposed within the vessel. A closure device covers an open end of the vessel to form a seal having vacuum and pressure capability. The system also includes a gas input tube, a gas exhaust tube, and a vacuum port. A gas supply network is coupled in flow communication with an end of the gas input tube and a gas supply network is coupled in flow communication with an end of the gas exhaust tube. A vacuum network is coupled in flow communication with one end of the vacuum port. A method and apparatus for purifying target material also are described.

Abstract: A method of determining a parameter of a patterning process, the method including: obtaining a detected representation of radiation redirected by a structure having geometric symmetry at a nominal physical configuration, wherein the detected representation of the radiation was obtained by illuminating a substrate with a radiation beam such that a beam spot on the substrate was filled with the structure; and determining, by a hardware computer system, a value of the patterning process parameter based on optical characteristic values from an asymmetric optical characteristic distribution portion of the detected radiation representation with higher weight than another portion of the detected radiation representation, the asymmetric optical characteristic distribution arising from a different physical configuration of the structure than the nominal physical configuration.

Abstract: Disclosed is an inspection apparatus and associated method for measuring a target structure on a substrate. The inspection apparatus comprises an illumination source for generating measurement radiation; an optical arrangement for focusing the measurement radiation onto said target structure; and a compensatory optical device. The compensatory optical device may comprise an SLM operable to spatially modulate the wavefront of the measurement radiation so as to compensate for a non-uniform manufacturing defect in said optical arrangement. In alternative embodiments, the compensatory optical device may be located in the beam of measurement radiation, or in the beam of pump radiation used to generate high harmonic radiation in a HHG source. Where located in the beam of pump radiation, the compensatory optical device may be used to correct pointing errors, or impart a desired profile or varying illumination pattern in a beam of the measurement radiation.

Abstract: A method of measuring wear of a substrate holder that is configured to hold a production substrate, the method includes: clamping a measurement substrate to the substrate holder; and measuring strain in the measurement substrate to generate a measurement result. The measurement substrate may have a body having dimensions similar to that of the production substrate; and a strain sensor in the body configured to measure strain in a peripheral portion of the measurement substrate.

Abstract: A method including: for a metrology target, having a first biased target structure and a second differently biased target structure, created using a patterning process, obtaining metrology data including signal data for the first target structure versus signal data for the second target structure, the metrology data being obtained for a plurality of different metrology recipes and each metrology recipe specifying a different parameter of measurement; determining a statistic, fitted curve or fitted function through the metrology data for the plurality of different metrology recipes as a reference; and identifying at least two different metrology recipes that have a variation of the collective metrology data of the at least two different metrology recipes from a parameter of the reference that crosses or meets a certain threshold.

Abstract: A substrate table for an immersion lithographic apparatus is disclosed having a recess, configured to receive a substrate of a given size, and a fluid extraction system, configured to extract fluid from a gap between the edge of the substrate and the edge of the recess, the fluid extraction system configured such that the rate of flow of fluid extracted from a localized section of the gap is greater than the rate of flow of fluid extracted from another section of the gap.

Abstract: A substrate holder for use in a lithographic apparatus and configured to support a substrate, the substrate holder including: a main body having a main body surface; and a plurality of burls projecting from the main body surface; wherein each burl has a distal end configured to engage with the substrate; the distal ends of the burls substantially conform to a support plane whereby a substrate can be supported in a substantially flat state on the burls; a frictional force between the distal end of each burl and a substrate engaged therewith arises in a direction parallel to the support plane in the event of a relative movement of the substrate and substrate holder in the direction; and distal end surfaces of the burls are provided with a release structure configured so that the frictional force is less than would arise in the absence of the release structure.

Abstract: A method of reducing an aberration of a lithographic apparatus, the method including measuring the aberration, taking the measured aberration into account, estimating a state of the lithographic apparatus, calculating a correction using the estimated state, and applying the correction to the lithographic apparatus.

Abstract: An immersion lithographic apparatus is provided with a liquid confinement structure which defines at least in part a space configured to contain liquid between the projection system and the substrate. In order to reduce the crossing of the edge of the substrate which is being imaged (which can lead to inclusion of bubbles in the immersion liquid), the cross-sectional area of the space in a plane parallel to the substrate is made as small as possible. The smallest theoretical size is the size of the target portion which is imaged by the projection system. In an embodiment, the shape of a final element of the projection system is also changed to have a similar size and/or shape in a cross-section parallel to the substrate to that of the target portion.

Abstract: A method including: obtaining a resist process dose sensitivity value for a patterning process; applying the resist process dose sensitivity value to a stochastic model providing values of a stochastic variable as a function of resist process dose sensitivity to obtain a value of the stochastic variable; and designing or modifying a parameter of the patterning process based on the stochastic variable value.