Abstract: Provided are light sources and methods of controlling them, and devices and methods for use in measurement applications, particularly in metrology, for example in a lithographic apparatus. The methods and devices provide mechanisms for detection and/or correction of variations in the light source, in particular stochastic variations. Feedback or feedforward approaches can be used for the correction of the source and/or the metrology outputs. An exemplary method of controlling the spectral output of a light source which emits a time-varying spectrum of light includes the steps of: determining at least one characteristic of the spectrum of light emitted from the light source; and using said determined characteristic to control the spectral output.

Abstract: Systems and methods for image enhancement are disclosed. A method for enhancing an image may include acquiring a scanning electron microscopy (SEM) image. The method may also include simulating diffused charge associated with a position of the SEM image. The method may further include providing an enhanced SEM image based on the SEM image and the diffused charge.

Abstract: A device manufacturing method, the method including: obtaining a measurement data time series of a plurality of substrates on which an exposure step and a process step have been performed; obtaining a status data time series relating to conditions prevailing when the process step was performed on at least some of the plurality of substrates; applying a filter to the measurement data time series and the status data time series to obtain filtered data; and determining, using the filtered data, a correction to be applied in an exposure step performed on a subsequent substrate.

Abstract: A method for optimizing a sequence of processes for manufacturing of product units, includes: associating measurement results of performance parameters (e.g., fingerprints) with the recorded process characteristics (e.g., context); obtaining a characteristic (e.g., context) of a previous process (e.g. deposition) in the sequence already performed on a product unit; obtaining a characteristic (e.g., context) of a subsequent process (e.g., exposure) in the sequence to be performed on the product unit; determining a predicted performance parameter (e.g., fingerprint) of the product unit associated with the sequence of previous and subsequent processes by using the obtained characteristics to retrieve measurement results of the performance parameters (e.g., fingerprints) corresponding to the recorded characteristics; and determining corrections to be applied to future processes (e.g. exposure, etch) in the sequence to be performed on the product unit, based on the determined predicted performance parameter.

Abstract: A feedthrough for providing an electrical connection is provided. The feedthrough comprises a conductor and a quartz or a glass structure configured to surround at least a portion of the conductor and provide isolation to the conductor. The conductor and the quartz or glass structure may be coaxially arranged. The feedthrough can provide an electrical connection between an inside and outside of a vacuum chamber that contains a sample.

Abstract: Disclosed herein an apparatus and a method for detecting buried features using backscattered particles. In an example, the apparatus comprises a source of charged particles; a stage; optics configured to direct a beam of the charged particles to a sample supported on the stage; a signal detector configured to detect backscattered particles of the charged particles in the beam from the sample; wherein the signal detector has angular resolution. In an example, the methods comprises obtaining an image of backscattered particles from a region of a sample; determining existence or location of a buried feature based on the image.

Abstract: A method of determining a measurement sequence for an inspection tool inspecting a structure generated by a lithographic process performed by a lithographic system is presented, the method including deriving a model for the lithographic process as performed by the lithographic system, the model including a relationship between a set of system variables describing the lithographic system and an output variable representing the structure resulting of the lithographic process, determining an observability of one or more system variables in the output variable, and determining the measurement sequence for the inspection tool, based on the observability.

Abstract: The invention provides a method of measuring an alignment mark or an alignment mark assembly, wherein the alignment mark comprises grid features extending in at least two directions, the method comprising: measuring the alignment mark or alignment mark assembly using an expected location of the alignment mark or alignment mark assembly, determining a first position of the alignment mark or alignment mark assembly in a first direction, determining a second position of the alignment mark or alignment mark assembly in a second direction, wherein the second direction is perpendicular to the first direction, determining a second direction scan offset between the expected location of the alignment mark or alignment mark assembly in the second direction and the determined second position, and correcting the first position on the basis of the second direction scan offset using at least one correction data set to provide a first corrected position.

Abstract: An object stage bearing system can include an object stage, a hollow shaft coupled to the object stage, and an in-vacuum gas bearing assembly coupled to the hollow shaft and the object stage. The in-vacuum gas bearing assembly can include a gas bearing, a scavenging groove, and a vacuum groove. The gas bearing is disposed along an inner wall of the in-vacuum gas bearing assembly and along an external wall of the hollow shaft. The scavenging groove is disposed along the inner wall such that the scavenging groove is isolated from the gas bearing. The vacuum groove is disposed along the inner wall such that the vacuum groove is isolated from the scavenging groove and the gas bearing.

Abstract: Methods of identifying a hot spot from a design layout or of predicting whether a pattern in a design layout is defective, using a machine learning model. An example method disclosed herein includes obtaining sets of one or more characteristics of performance of hot spots, respectively, under a plurality of process conditions, respectively, in a device manufacturing process; determining, for each of the process conditions, for each of the hot spots, based on the one or more characteristics under that process condition, whether that hot spot is defective; obtaining a characteristic of each of the process conditions; obtaining a characteristic of each of the hot spots; and training a machine learning model using a training set including the characteristic of one of the process conditions, the characteristic of one of the hot spots, and whether that hot spot is defective under that process condition.

Abstract: A micromirror array comprises a substrate, a plurality of minors for reflecting incident light and, for each mirror (20) of the plurality of minors, at least one piezoelectric actuator (21) for displacing the minor, wherein the at least one piezoelectric actuator is connected to the substrate. The micromirror array further comprises one or more pillars (24) connecting the minor to the at least one piezoelectric actuator. Also disclosed is a method of forming such a micromirror array. The micromirror array may be used in a programmable illuminator. The programmable illuminator may be used in a lithographic apparatus and/or in an inspection apparatus.

Abstract: A substrate holder for supporting a substrate, a lithographic apparatus having the substrate holder and a method of supporting the substrate. The substrate holder includes a main body, a plurality of supporting pins, and a plate. The plate is positioned between a surface of the main body and a support surface formed by the plurality of supporting pins. The plate is actuatable in a direction along the plurality of supporting pins between the surface of the main body and the support surface. The substrate holder may also include a main body, a flexible member and a fixed member protruding from a surface of the main body. The flexible member defines an enclosed cavity therein and configured to form a seal with the substrate supported on the substrate holder. The substrate holder is configured to reduce pressure in the enclosed cavity of the flexible member.

Abstract: A method of controlling a computer process for designing or verifying a photolithographic component, the method including building a source tree including nodes of the process, including dependency relationships among the nodes, defining, for some nodes, at least two different process conditions, expanding the source tree to form an expanded tree, including generating a separate node for each different defined process condition, and duplicating dependent nodes having an input relationship to each generated separate node, determining respective computing hardware requirements for processing the node, selecting computer hardware constraints based on capabilities of the host computing system, determining, based on the requirements and constraints and on dependency relations in the expanded tree, an execution sequence for the computer process, and performing the computer process on the computing system.

Abstract: The disclosure relates to determining information about a target structure formed on a substrate using a lithographic process. In one arrangement, a cantilever probe is provided having a cantilever arm and a probe element. The probe element extends from the cantilever arm towards the target structure. Ultrasonic waves are generated in the cantilever probe. The ultrasonic waves propagate through the probe element into the target structure and reflect back from the target structure into the probe element or into a further probe element extending from the cantilever arm. The reflected ultrasonic waves are detected and used to determine information about the target structure.

Abstract: A method for training a machine learning model configured to predict values of a physical characteristic associated with a substrate and for use in adjusting a patterning process. The method involves obtaining a reference image; determining a first set of model parameter values of the machine learning model such that a first cost function is reduced from an initial value of the cost function obtained using an initial set of model parameter values, where the first cost function is a difference between the reference image and an image generated via the machine learning model; and training, using the first set of model parameter values, the machine learning model such that a combination of the first cost function and a second cost function is iteratively reduced, the second cost function representing a difference between measured values and predicted values.

Abstract: A method of determining an overlay measurement associated with a substrate and a system to obtain an overlay measurement associated with a patterning process. A method for determining an overlay measurement may be used in a lithography patterning process. The method includes generating a diffraction signal by illuminating a first overlay pattern and a second overlay pattern using a coherent beam. The method also includes obtaining an interference pattern based on the diffraction signal. The method further includes determining an overlay measurement between the first overlay pattern and the second overlay pattern based on the interference pattern.

Abstract: A sensor apparatus includes a sensor chip, an illumination system, a first optical system, a second optical system, and a detector system. The illumination system is coupled to the sensor chip and transmits an illumination beam along an illumination path. The first optical system is coupled to the sensor chip and includes a first integrated optic to configure and transmit the illumination beam toward a diffraction target on a substrate, disposed adjacent to the sensor chip, and generate a signal beam including diffraction order sub-beams generated from the diffraction target. The second optical system is coupled to the sensor chip and includes a second integrated optic to collect and transmit the signal beam from a first side to a second side of the sensor chip. The detector system is configured to measure a characteristic of the diffraction target based on the signal beam transmitted by the second optical system.

Abstract: A method of reducing variability of an error associated with a structure on a substrate in a lithography process is disclosed. The method includes determining, based on one or more images obtained based on a scan of the substrate by a scanning electron microscope (SEM), a first error due to a SEM distortion in the image. The method also includes determining, based on the image, a second error associated with a real error of the structure, where the error associated with the structure includes the first error and the second error. A command is generated by a data processor that enables a modification of the lithography process and an associated reduction of the variability of the error based on reducing any of the first error or the second error.

Abstract: A method of determining a set of metrology point locations, the set including a subset of potential metrology point locations on a substrate, the method including: determining a relation between noise distributions associated with a plurality of the potential metrology point locations using existing knowledge; and using the determined relation and a model associated with the substrate to determine the set.

Abstract: A method of calculating process corrections for a lithographic tool, and associated apparatuses. The method comprises measuring process defect data on a substrate that has been previously exposed using the lithographic tool; fitting a process signature model to the measured process defect data, so as to obtain a model of the process signature for the lithographic tool; and using the process signature model to calculate the process corrections for the lithographic tool.