Abstract: A method comprising the steps of receiving a mask assembly comprising a mask and a removable EUV transparent pellicle held by a pellicle frame, removing the pellicle frame and EUV transparent pellicle from the mask, using an inspection tool to inspect the mask pattern on the mask, and subsequently attaching to the mask an EUV transparent pellicle held by a pellicle frame. The method may also comprise the following steps: after removing the pellicle frame and EUV transparent pellicle from the mask, attaching to the mask an alternative pellicle frame holding an alternative pellicle formed from a material which is substantially transparent to an inspection beam of the inspection tool; and after using an inspection tool to inspect the mask pattern on the mask, removing the alternative pellicle held by the alternative pellicle frame from the mask in order to attach to the mask the EUV transparent pellicle held by the pellicle frame.

Abstract: The invention relates to an alignment apparatus for aligning a substrate, and a substrate processing system comprising such alignment apparatus. The alignment apparatus comprises an alignment base for supporting said substrate and/or a substrate support member, and a force generating device for applying a contact force on said substrate. The force generating device comprises: an arm comprising a rigid proximal end a rigid distal end provided with a contact section for contacting an edge of said substrate, and an elastically deformable arm section extending between the rigid proximal and distal ends, a connection part connecting said rigid proximal end to said alignment base, said arm being movable with respect to said alignment base via said connection part, and an actuator for acting on and causing a displacement of said rigid proximal end, whereby said contact force, defined by said elastically deformable arm section, is applied to said substrate by said contact section.

Abstract: A lithographic apparatus has a support structure constructed to support a patterning device and associated pellicle, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam, and a projection system configured to project the patterned radiation beam onto a target portion of a substrate, wherein the support structure is located in a housing and wherein pressure sensors are located in the housing.

Abstract: A substrate table configured to support a substrate for exposure in an immersion lithographic apparatus, the substrate table including: a support body having a support surface configured to support the substrate; and a cover ring fixed relative to the support body and configured to surround, in plan view, the substrate supported on the support surface, wherein the cover ring has an upper surface and at least a portion of the upper surface is configured so as to alter the stability of a meniscus of immersion liquid when moving along the upper surface towards the substrate.

Abstract: Methods of determining an optimal focus height are disclosed. In one arrangement, measurement data from a plurality of applications of the metrology process to a target are obtained. Each application of the metrology process includes illuminating the target with a radiation spot and detecting radiation redirected by the target. The applications of the metrology process include applications at different nominal focus heights. The measurement data includes, for each application of the metrology process, at least a component of a detected pupil representation of an optical characteristic of the redirected radiation in a pupil plane. The method includes determining an optimal focus height for the metrology process using the obtained measurement data.

Abstract: Focus performance of a lithographic apparatus is measured using pairs of targets that have been exposed (1110) with an aberration setting (e.g. astigmatism) that induces a relative best focus offset between them. A calibration curve (904) is obtained in advance by exposing similar targets on FEM wafers (1174, 1172). In a set-up phase, calibration curves are obtained using multiple aberration settings, and an anchor point (910) is recorded, where all the calibration curves intersect. When a new calibration curve is measured (1192), the anchor point is used to produce an adjusted updated calibration curve (1004?) to cancel focus drift and optionally to measure drift of astigmatism. Another aspect of the disclosure (FIGS. 13-15) uses two aberration settings (+AST, ?AST) in each measurement, reducing sensitivity to astigmatism drift. Another aspect (FIGS. 16-17) uses pairs of targets printed with relative focus offsets, by double exposure in one resist layer.

Abstract: One modified source-conversion unit and one method to reduce the Coulomb Effect in a multi-beam apparatus are proposed. In the modified source-conversion unit, the aberration-compensation function is carried out after the image-forming function has changed each beamlet to be on-axis locally, and therefore avoids undesired aberrations due to the beamlet tilting/shifting. A Coulomb-effect-reduction means with plural Coulomb-effect-reduction openings is placed close to the single electron source of the apparatus and therefore the electrons not in use can be cut off as early as possible.

Abstract: A liquid supply system for an immersion lithographic projection apparatus is disclosed in which a space is defined between the projection system, a barrier member and a substrate. The barrier member is not sealed such that, during use, immersion liquid is allowed to flow out the space and between the barrier member and the substrate.

Abstract: A mask assembly suitable for use in a lithographic process, the mask assembly comprising a patterning device; and a pellicle frame configured to support a pellicle and mounted on the patterning device with a mount; wherein the mount is configured to suspend the pellicle frame relative to the patterning device such that there is a gap between the pellicle frame and the patterning device; and wherein the mount provides a releasably engageable attachment between the patterning device and the pellicle frame.

Abstract: A metrology apparatus for determining a parameter of interest of a structure formed by a lithographic process on a substrate, the metrology apparatus comprising: an illuminator for illuminating the structure; a lens for collecting at least a portion of radiation diffracted from the structure; and an image sensor for receiving and obtaining a recording of the collected diffracted radiation; wherein the illuminator comprises at least one optical fiber for illuminating the structure directly.

Abstract: A radiation analysis system comprising a target comprising two marks which are separated from each other, the target being configured to undergo thermal expansion when illuminated with radiation; a position measurement system configured to measure a change in the separation of the marks; and a processor configured to determine a power of the radiation using the measured change in separation of the marks.

Abstract: Offline metrology measurements are performed on substrates that have been subjected to lithographic processing. Model parameters are calculated by fitting the measurements to an extended high-order substrate model defined using a combination of basis functions that include an edge basis function related to a substrate edge. A radial edge basis function may be expressed in terms of distance from a substrate edge. The edge basis function may, for example, be an exponential decay function or a rational function. Lithographic processing of a subsequent substrate is controlled using the calculated high-order substrate model parameters, in combination with low-order substrate model parameters obtained by fitting inline measurements to a low order model.

Abstract: A method of determining an estimated intensity of radiation scattered by a target illuminated by a radiation source, has the following steps: obtaining and training (402) a library REFLIB of wavelength-dependent reflectivity as a function of the wavelength, target structural parameters and angle of incidence R(?,?,x,y); determining (408) a wide-band library (W-BLIB) of integrals of wavelength-dependent reflectivity R of the target in a Jones framework over a range of radiation source wavelengths ?; training (TRN) (410) the wide-band library; and determining (412), using the trained wide-band library, an estimated intensity (INT) of radiation scattered by the target illuminated by the radiation source.

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: Overlay error of a lithographic process is measured using a plurality of target structures, each target structure having a known overlay bias. A detection system captures a plurality of images (740) representing selected portions of radiation diffracted by the target structures under a plurality of different capture conditions (?1, ?2). Pixel values of the captured images are combined (748) to obtain one or more synthesized images (750). A plurality of synthesized diffraction signals are extracted (744) from the synthesized image or images, and used to calculate a measurement of overlay. The computational burden is reduced compared with extracting diffraction signals from the captured images individually. The captured images may be dark-field images or pupil images, obtained using a scatterometer.

Abstract: An overlay metrology target (600, 900, 1000) contains a plurality of overlay gratings (932-935) formed by lithography. First diffraction signals (740(1)) are obtained from the target, and first asymmetry values (As) for the target structures are derived. Second diffraction signals (740(2)) are obtained from the target, and second asymmetry values (As?) are derived. The first and second diffraction signals are obtained using different capture conditions and/or different designs of target structures and/or bias values. The first asymmetry signals and the second asymmetry signals are used to solve equations and obtain a measurement of overlay error. The calculation of overlay error makes no assumption whether asymmetry in a given target structure results from overlay in the first direction, in a second direction or in both directions. With a suitable bias scheme the method allows overlay and other asymmetry-related properties to be measured accurately, even in the presence of two-dimensional overlay structure.

Abstract: A lithographic process is performed on a plurality of semiconductor substrates. The method includes selecting one or more of the substrates as one or more sample substrates. Metrology steps are performed only on the selected one or more sample substrates. Based on metrology results of the selected one or more sample substrates, corrections are defined for use in controlling processing of the substrates or of future substrates. The selection of the one or more sample substrates is based at least partly on statistical analysis of object data measured in relation to the substrates. The same object data or other data can be used for grouping substrates into groups. Selecting of one or more sample substrates can include selecting substrates that are identified by the statistical analysis as most representative of the substrates in their group and/or include elimination of one or more substrates that are identified as unrepresentative.

Abstract: A method and control system for determining stress in a substrate. The method includes determining a measured position difference between a measured position of at least one first feature and a measured position of at least one second feature which have been applied on a substrate, and determining local stress in the substrate from the measured position difference.

Abstract: A method including: obtaining a portion of a design layout; determining characteristics of assist features based on the portion or characteristics of the portion; and training a machine learning model using training data including a sample whose feature vector includes the characteristics of the portion and whose label includes the characteristics of the assist features. The machine learning model may be used to determine characteristics of assist features of any portion of a design layout, even if that portion is not part of the training data.

Abstract: A motor assembly includes linear motors, each linear motor configured to generate a driving force in a driving direction and each having a first electromagnetic assembly and a second electromagnetic assembly, configured to co-operate with the first electromagnetic assembly, for generating the driving force, wherein the first electromagnetic assembly and the second electromagnetic assembly face each other and define a gap between each other in a direction perpendicular to the driving direction. A first interface connects the first electromagnetic assemblies to a common member. A second interface connects the second electromagnetic assemblies to the object to be driven.