A method of training a generator model comprising: using the generator model to generate the predictive data based on the first measured data, wherein the first measured data and the predictive data can be used to form images of the sample; pairing subsets of the first measured data with subsets of the predictive data, the subsets corresponding to locations within the images of the sample that can be formed from the first measured data and the predictive data; using a discriminator to evaluate a likelihood that the predictive data comes from a same data distribution as second measured data measured from a sample after an etching process; and training the generator model based on: correlation for the pairs corresponding to a same location relative to correlation for pairs corresponding to different locations, the correlation being the correlation between the paired subsets of data, and the likelihood evaluated by the discriminator.

The invention relates to a computer implemented method for simulating an aerial image of a model of a photolithography mask illuminated by incident electromagnetic waves, the method comprising: obtaining the model of the photolithography mask, the model describing the photolithography mask at least partially in a dimension orthogonal to the mask carrier plane; simulating the propagation of the incident electromagnetic waves through the model of the photolithography mask using a machine learning model, wherein the machine learning model maps the model of the photolithography mask to a representation of an electromagnetic field generated by the incident electromagnetic waves on the photolithography mask; obtaining the aerial image of the model of the photolithography mask by applying a simulation of an imaging process. The invention also relates to corresponding computer programs, computer-readable media and systems.

A method for calculating a spatial map associated with a component, the spatial map indicating spatial variations of thermal expansion parameters in the component, the method comprising: providing or determining a temperature distribution in the component as a function of time; calculating the spatial map associated with the component using the provided or determined temperature distribution in the component and optical measurements of a radiation beam that has interacted directly or indirectly with the component, the optical measurements being time synchronized with the provided or determined temperature distribution in the component.

A method of optimizing maintenance of a lithographic apparatus. The method including obtaining productivity data relating to a productivity of a lithographic apparatus and error metric data relating to the effect of a maintenance action on exposure performance. The productivity data and error metric data is used to determine such that a loss of productivity metric is reduced or minimized, one or both of: a number of layers to ramp down in production of integrated circuits prior to the maintenance action on the lithographic apparatus, the layers being lithographically exposed on each of a plurality of substrates using the lithographic apparatus; and/or a maintenance schedule metric relating to the frequency of performance of the maintenance action.

An illumination mode selector for use in an illumination branch of an optical metrology tool, and an associated optical metrology tool. The illumination mode selector includes a plurality of illumination apertures; and at least one polarization-changing optical element. Each of the illumination apertures and each of the at least one polarization-changing optical element are individually switchable into an illumination path of the optical metrology tool.

An analytical method and an analytical apparatus for quantitatively calculating line edge roughness of plasmon super diffraction photolithography. The method includes: determining a theoretical point spread function of a light source based on field intensity distribution of the light source at an exit plane of a focusing element of the plasmon super diffraction photolithography; determining multiple transverse widths of spots in a spot-mapping pattern based on the spot-mapping pattern; determining actual point spread functions corresponding to the multiple transverse widths, based on the theoretical point spread function and the multiple transverse widths; and establishing an analytical equation of line edge roughness of the plasmon super diffraction photolithography based on the variation due to line edge roughness, an exposure dose of each line pattern, the near-field photoresist contrast, and the logarithmic slope of each line pattern. Applicability of surface plasma super diffraction photolithography technology is greatly improved.

A method for performing a lithographic apparatus setup calibration and/or drift correction for a specific lithographic apparatus of a population of lithographic apparatuses to be used in a manufacturing process for manufacturing an integrated circuit extending across a plurality of layers on a substrate. The method includes determining a spatial error distribution of an apparatus parameter across spatial coordinates on the substrate for each lithographic apparatus of the population of lithographic apparatuses and/or each layer of the plurality of layers; determining a reference distribution by aggregating each of the spatial error distributions to optimize the reference distribution such that a spatial distribution of a parameter of interest of the manufacturing process is co-optimized across the population of lithographic apparatuses and/or plurality of layers; and using the reference distribution as a target distribution for the apparatus parameter for each lithographic apparatus and/or layer.

In some implementations, a metrology optimization system may obtain three-dimensional (3D) model information associated with an object. The metrology optimization system may obtain optical sensor information associated with a metrology system that is to measure the object. The metrology optimization system may determine, based on the 3D model information and the optical sensor information, an initial configuration for the metrology system. The metrology optimization system may determine, based on the 3D model information, the optical sensor information, and the initial configuration, an optimal configuration for the metrology system. The metrology optimization system may provide the optimal configuration for the metrology system.

A method for estimating process characteristics is provided. The method can include collecting process data from a spectral emitter and a spectral sensor during a substrate processing operation, and generating a calibrated model for the process data. Generating a calibrated model can include selecting a calibration option from a set of calibration options, based on a degree of freedom associated with a given calibration option, and calibrating a base model to generate the calibrated model. The base model is calibrated using the selected calibration option and a portion of the first process data.

A method for generating a retargeted pattern for a target pattern to be printed on a substrate. The method includes obtaining (i) the target pattern comprising at least one feature, the at least one feature having geometry including a first dimension and a second dimension, and (ii) a plurality of biasing rules defined as a function of the first dimension, the second dimension, and a property associated with features of the target pattern within a measurement region; determining values of the property at a plurality of locations on the at least one feature of the target pattern, each location surrounded by the measurement region; selecting, from the plurality of biasing rules based on the values of the property, a sub-set of biases; and generating the retargeted pattern by applying the selected sub-set of biases to the at least one feature of the target pattern.