Abstract: An actuator comprises a coil, a first cooling plate and a second cooling plate. The cooling plates are configured to cool the coil. The first and second cooling plates are arranged at opposite sides of the coil to be in thermal contact with the coil. The coil comprises a first coil part and a second coil part, the first coil part facing the first cooling plate and the second coil part facing the second cooling plate, the first and second coil parts being separated by a spacing there between. The first cooling plate, the first coil part, the spacing, the second coil part and the second cooling plate form a stacked structure whereby the coil parts are arranged between the cooling plates and the spacing is arranged between the coil parts. The actuator further comprises a filling element arranged in the spacing. The filling element to push the first coil part towards the first cooling plate and to push the second coil part towards the second cooling plate.

Abstract: Disclosed herein is an multi-array lens configured in use to focus a plurality of beamlets of charged particles along a multi-beam path, wherein each lens in the array comprises: an entrance electrode; a focusing electrode and a support. The focusing electrode is down beam of the entrance electrode along a beamlet path and is configured to be at a potential different from the entrance electrode. The support is configured to support the focusing electrode relative to the entrance electrode. The focusing electrode and support are configured so that in operation the lens generates a rotationally symmetrical field around the beamlet path.

Abstract: Disclosed is a method of metrology such as alignment metrology. The method comprises obtaining pupil plane measurement dataset at a pupil plane relating to scattered radiation resultant from a measurement of a structure. The method comprises determining a measurement value or correction therefor using the pupil plane measurement dataset and a sensor term relating to sensor optics used to perform said measurement.

Abstract: Apparatus and method for measuring one or more parameters of a substrate (300) using source radiation emitted from a radiation source (100) and directed onto the substrate. The apparatus comprises at least one reflecting element (710a) and at least one detector (720, 721). The at least one reflecting element is configured to receive a reflected radiation resulting from reflection of the source radiation from the substrate and further reflect the reflected radiation into a further reflected radiation.

Abstract: An alignment apparatus includes an illumination system configured to direct one or more illumination beams towards an alignment target and receive the diffracted beams from the alignment target. The alignment apparatus also includes a self-referencing Interferometer configured to generate two diffraction sub-beams, wherein the two diffraction sub-beams are orthogonally polarized, rotated 180 degrees with respect to each other around an alignment axis, and spatially overlapped. The alignment apparatus further includes a beam analyzer configured to generate interference between the overlapped components of the diffraction sub-beams and produce two orthogonally polarized optical branches, and a detection system configured to determine a position of the alignment target based on light intensity measurement of the optical branches, wherein the measured light intensity is temporally modulated by a phase modulator.

Abstract: An apparatus and method to determine a property of a substrate by measuring, in the pupil plane of a high numerical aperture lens, an angle-resolved spectrum as a result of radiation being reflected off the substrate. The property may be angle and wavelength dependent and may include the intensity of TM- and TE-polarized radiation and their relative phase difference.

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.

Abstract: Methods and apparatus for determining a subset of a plurality of relationships between a plurality of parameters describing operation of a lithographic apparatus, the method comprising: determining a first set of data describing first relationships between a plurality of parameters of a reference apparatus; based on one or more measurements, determining a second set of data describing second relationships between the plurality of parameters of the reference or a further apparatus; comparing the first set of data and the second set of data; and selecting from the second set of data a subset of the second relationships based on differences between the first set of data and the second set of data.

Abstract: Systems and methods for in-die metrology using target design patterns are provided. These systems and methods include selecting a target design pattern based on design data representing the design of an integrated circuit, providing design data indicative of the target design pattern to enable design data derived from the target design pattern to be added to second design data, wherein the second design data is based on the first design data. Systems and methods can further include causing structures derived from the second design data to be printed on a wafer, inspecting the structures on the wafer using a charged-particle beam tool, and identifying metrology data or process defects based on the inspection. In some embodiments the systems and methods further include causing the charged-particle beam tool, the second design data, a scanner, or photolithography equipment to be adjusted based on the identified metrology data or process defects.

Abstract: A high harmonic radiation source and associated method of generating high harmonic radiation is disclosed. The high harmonic radiation source is configured to condition a gas medium by irradiating the gas medium with a pre-pulse of radiation, thereby generating a plasma comprising a pre-pulse plasma distribution; and irradiate the gas medium with a main pulse of radiation to generate said high harmonic radiation. The conditioning step is such that the plasma comprising a pre-pulse plasma distribution acts to configure a wavefront of said main pulse to improve one or both of: the efficiency of the high harmonic generation process and the beam quality of the high harmonic radiation. The high harmonic radiation source further may comprise a beam shaping device configured to shape said customized pre-pulse prior to said conditioning.

Abstract: A charged-particle assessment tool comprising a plurality of beam columns. Each beam column comprises: a charged-particle beam source configured to emit charged particles; a plurality of condenser lenses configured to form charged particles emitted from the charged-particle beam source into a plurality of charged-particle beams; and a plurality of objective lenses, each configured to project one of the plurality of charged-particle beams onto a sample. The beam columns are arranged adjacent one-another so as to project the charged particle beams onto adjacent regions of the sample.

Abstract: A charged-particle assessment tool comprising: a condenser lens array, a collimator, a plurality of objective lenses and an electric power source. The condenser lens array configured to divide a beam of charged particles into a plurality of sub-beams and to focus each of the sub-beams to a respective intermediate focus. The collimator being at each intermediate focus and configured to deflect a respective sub-beam so that it is incident on the sample substantially normally. The plurality of objective lenses, each configured to project one of the plurality of charged-particle beams onto a sample. Each objective lens comprises: a first electrode; and a second electrode that is between the first electrode and the sample. The electric power source configured to apply first and second potentials to the first and second electrodes respectively such that the respective charged-particle beam is decelerated to be incident on the sample with a desired landing energy.

Abstract: A calibration system includes a plate, a fixed alignment mark, and a variable diffraction grating. The plate is adjacent to a wafer alignment mark disposed on a wafer. The fixed alignment mark is disposed on the plate and is configured to act as a reference mark for an initial calibration of the calibration system. The variable diffraction grating is disposed on the plate and includes a plurality of unit cells configured to form a plurality of variable alignment marks. The variable diffraction grating is configured to calibrate a shift-between-orders of one of the variable alignment marks and the fixed alignment mark.

Abstract: Disclosed is a method of determining calibrated reference exposure and measure grids for referencing position of a substrate stage in a lithographic system. The method comprises obtaining calibration data relating to one or more calibration substrates; and determining an exposure grid for an exposure side of the lithographic system from said calibration data and a measure grid for a measure side of the lithographic system from said calibration data. The exposure grid and said measure grid are decomposed so as to remove a calibration substrate dependent component from said exposure grid and from said measure grid to obtain a substrate independent exposure grid and substrate independent measure grid.

Abstract: A radiation source for an EUV lithography apparatus is disclosed. The radiation source comprises a chamber comprising a plasma formation region, a radiation collector arranged in the chamber and configured to collect radiation emitted at the plasma formation region and to direct the collected radiation towards an intermediate focus region, and a radiation conduit disposed between the radiation collector and the intermediate focus region. The radiation conduit comprises at least one outlet on an inner surface of a wall of the radiation conduit for directing a protective gas flow, and at least one guide portion extending from the inner surface of the wall of the radiation conduit and configured to redirect the protective gas flow. Also disclosed is a method of reducing debris and/or vapor deposition in the radiation conduit by providing a protective gas flow to the at least one outlet of the radiation conduit.

Abstract: Disclosed herein is an electron-optical assembly testing system for testing an electron-optical assembly, the system comprising: a source of charged particles configured to emit a beam of charged particles; an electron-optical assembly holder configured to hold an electron-optical assembly to be tested such that, when the system is in use with an electron-optical assembly held by the electron-optical assembly holder, the electron-optical assembly is illuminated by the beam; and a sub-beam detector for detecting sub-beams of charged particles that have been transmitted through the electron-optical assembly.

Abstract: A method of optimizing an apparatus for multi-stage processing of product units such as wafers, the method includes: receiving object data representing one or more parameters measured across the product units and associated with different stages of processing of the product units; and determining fingerprints of variation of the object data across the product units, the fingerprints being associated with different respective stages of processing of the product units. The fingerprints may be determined by decomposing the object data into components using principal component analysis for each different respective stage; analyzing commonality of the fingerprints through the different stages to produce commonality results; and optimizing an apparatus for processing product units based on the commonality results.

Abstract: An optical height detection system in a charged particle beam inspection system. The optical height detection system includes a projection unit including a modulated illumination source, a projection grating mask including a projection grating pattern, and a projection optical unit for projecting the projection grating pattern to a sample; and a detection unit including a first detection grating mask including a first detection grating pattern, a second detection grating mask including a second detection grating pattern, and a detection optical system for forming a first grating image from the projection grating pattern onto the first detection grating mask and forming a second grating image from the projection grating pattern onto the second detection grating masks. The first and second detection grating patterns at least partially overlap the first and second grating images, respectively.

Abstract: A method including: computing a value of a first variable of a pattern of, or for, a substrate processed by a patterning process by combining a fingerprint of the first variable on the substrate and a certain value of the first variable; and determining a value of a second variable of the pattern based at least in part on the computed value of the first variable.

Abstract: Disclosed is a method for determining a stage position or correction therefor in a lithographic process. The method comprises obtaining transmission data describing the transmission of alignment radiation onto the substrate; obtaining position data relating to a stage position of said stage and/or a sensor position of said sensor. A weighting is determined for the position data based on said transmission data. The position based on said transmission data, position data and weighting.