A lithographic apparatus includes a substrate table capable of holding a substrate, a projection system that projects a patterned beam of radiation onto the substrate held by the substrate table, and a sensor table that is not capable of holding a substrate but that includes a sensor capable of sensing a property of the patterned beam of radiation. In addition, a first positioning system is connected to the substrate table and displaces the substrate table into and out of a path of the patterned beam of radiation, and a second positioning system is capable of positioning the sensor table into the path of the patterned beam of radiation when the substrate table is displaced out of the path of the patterned beam of radiation.

The present disclosure provides a method that includes capturing a first image of a mask in a first exposure apparatus using a first exposure source and a first imaging sensor; capturing a second image of the mask in a second exposure apparatus using a second exposure source and a second imaging sensor; comparing the first image of the mask and the second image of the mask for a difference therebetween; and determining an action according to the difference.

A reflective sample, such as a mask, is imaged in an optics system. A radiation source emits a light beam with relatively low coherence. A first focusing element focuses the beam before a mirror reflects the focused beam towards the sample at an incidence angle of between 2 and 25 A pinhole aperture plate upstream of the sample has a first aperture to focus and cut-off the beam diameter to form a more monochromatic beam. The sample is displaced by a mechanism in a direction perpendicular to the normal vector of the sample surface while it reflects the light beam. The reflected beam passes a second aperture in the pinhole aperture plate next to the first aperture on its way to a pixel detector. The second aperture limits the diameter of the reflected beam, thereby adjusting the diameter of the light beam before it reaches the pixel detector.

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.

Disclosed is a resist pattern prediction device, which includes an optical proximity correction module for generating both an optical proximity correction and a non-optical proximity correction. The optical proximity correction module generates an aerial image by performing an optical proximity correction based on a mask image. The module also generates a resist image by performing a non-optical proximity correction on the mask image and the aerial image. The resist pattern prediction device also includes a pattern prediction module that predicts information with respect to a resist pattern based on the resist image. The non-optical proximity correction includes performing a convolution operation on the aerial image using a Volterra kernel based on a coefficient of a quadratic term of a Volterra series.

The present invention provides an evaluation method of evaluating optical characteristics of a projection optical system by obtaining, by a prediction formula, a predicted value for a fluctuation amount of the optical characteristics relative to an exposure period of a substrate via the projection optical system, the method comprising determining the prediction formula by using a dedicated pattern in which a plurality of marks are arranged in a matrix on an object plane of the projection optical system, wherein the determining includes selecting, from the plurality of marks, at least two marks located in an illuminated region to be formed on the object plane when exposing the substrate, and obtaining the prediction formula based on positions of images of the at least two marks formed on an image plane of the projection optical system.

Disclosed is a method for determining a parameter of interest relating to at least one target on a substrate. The method comprises obtaining metrology data comprising at least one asymmetry signal, said at least one asymmetry signal comprising a difference or imbalance in a measurement parameter from the target; obtaining a trained model having been trained or configured to relate said at least one asymmetry signal to the parameter of interest, the trained model comprising at least one proxy for at least one nuisance component of the at least one asymmetry signal; and inferring said parameter of interest for said at least one target from said at least one asymmetry signal using the trained model.

In order to determine a production aerial image of an object to be measured as a result of an illumination and imaging with illumination and imaging conditions of an optical production system, firstly a measurement aerial image of the object to be measured is captured. This is carried out with illumination and imaging conditions of an optical measurement system, which conditions include a predefined measurement illumination setting. Data of the measurement aerial image are generated during the capturing. An object structure of the object to be measured is reconstructed from the data of the captured measurement aerial image by use of a reconstruction algorithm. Data of the reconstructed object structure are generated during the reconstructing. A production aerial image is simulated from the data of the reconstructed object structure with the illumination and imaging conditions of the optical production system. Said conditions include a production illumination setting, which is different than the measurement illumination setting. This results in a determining method in which the requirements made of an optical measurement system used in the determining method, even under demanding illumination and imaging conditions of the optical production system, are relaxed.

A method of determining a relationship between a stochastic variation of a characteristic of an aerial image or a resist image and one or more design variables, the method including: measuring values of the characteristic from a plurality of aerial images and/or resist images for each of a plurality of sets of values of the one or more design variables; determining a value of the stochastic variation, for each of the plurality of sets of values of the one or more design variables, from a distribution of the values of the characteristic for that set of values of the one or more design variables; and determining the relationship by fitting one or more parameters from the values of the stochastic variation and the plurality of sets of values of the one or more design variables.

A method for determining process window limiting patterns based on aberration sensitivity associated with a patterning apparatus. The method includes obtaining (i) a first set of kernels and a second set of kernels associated with an aberration wavefront of the patterning apparatus and (ii) a design layout to be printed on a substrate via the patterning apparatus; and determining, via a process simulation using the design layout, the first set of kernels, and the second set of kernels, an aberration sensitivity map associated with the aberration wavefront, the aberration sensitivity map indicating how sensitive one or more portions of the design layout are to an individual aberrations and an interaction between different aberrations; determining, based on the aberration sensitivity map, the process window limiting pattern associated with the design layout having relatively high sensitivity compared to other portions of the design layout.