Abstract:
An apparatus for receiving an input radiation beam at a beam receiving location and outputting from the beam receiving location one or more output radiation beams. The apparatus comprises: an optical element; and a movement mechanism. The optical element comprises a plurality of portions for receiving the input radiation beam. The movement mechanism is operable to move the plurality of portions so as selectively position each of the plurality of portions at the beam receiving location. When one of the plurality of portions is disposed in the beam receiving location it is configured to receive the input radiation beam and to scatter the input radiation beam so as to form the one or more output radiation beams. A direction of each of the one or more output radiation beams formed by each of the plurality of portions is substantially the same as a direction of a corresponding output radiation beam formed by each of the other portions. One or more properties of each of the plurality of portions differs from that of the other portions such that a power of at least one of the one or more output radiation beams formed by each of the plurality of portions is different to that of the corresponding output radiation beam formed by at least one of the other portions.
Abstract:
Disclosed is a method of monitoring a focus parameter during a lithographic process. The method comprises acquiring first and second measurements of, respectively first and second targets, wherein the first and second targets have been exposed with a relative best focus offset. The method then comprises determining the focus parameter from first and second measurements. Also disclosed are corresponding measurement and lithographic apparatuses, a computer program and a method of manufacturing devices.
Abstract:
Described herein is a method. The method includes steps for obtaining (i) measurements of a parameter of the feature, (ii) data related to a process variable of a patterning process, (iii) a functional behavior of the parameter defined as a function of the process variable based on the measurements of the parameter and the data related to the process variable, (iv) measurements of a failure rate of the feature, and (v) a probability density function of the process variable for a setting of the process variable, converting the probability density function of the process variable to a probability density function of the parameter based on a conversion function, where the conversion function is determined based on the function of the process variable, and determining a parameter limit of the parameter based on the probability density function of the parameter and the measurements of the failure rate.
Abstract:
Disclosed is a method of monitoring a lithographic process parameter, such as focus and/or dose, of a lithographic process. The method comprises acquiring a first and a second target measurement using respectively a first measurement configuration and a second measurement configuration, and determining the lithographic process parameter from a first metric derived from said first target measurement and said second target measurement. The first metric may be difference. Also disclosed are corresponding measurement and lithographic apparatuses, a computer program and a method of manufacturing devices.
Abstract:
Disclosed is a method of determining a characteristic of interest relating to a structure on a substrate formed by a lithographic process, the method comprising: obtaining an input image of the structure; and using a trained neural network to determine the characteristic of interest from said input image. Also disclosed is a reticle comprising a target forming feature comprising more than two sub-features each having different sensitivities to a characteristic of interest when imaged onto a substrate to form a corresponding target structure on said substrate. Related methods and apparatuses are also described.
Abstract:
Disclosed is a method of measuring focus performance of a lithographic apparatus, and corresponding patterning device and lithographic apparatus. The method comprises using the lithographic apparatus to print one or more first printed structures and second printed structures. The first printed structures are printed by illumination having a first non-telecentricity and the second printed structures being printed by illumination having a second non-telecentricity, different to said first non-telecentricity. A focus dependent parameter related to a focus- dependent positional shift between the first printed structures and the second printed structures on said substrate is measured and a measurement of focus performance based at least in part on the focus dependent parameter is derived therefrom.
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 (Fig. 13-15) uses two aberration settings (+AST, -AST) in each measurement, reducing sensitivity to astigmatism drift. Another aspect (Fig. 16-17) uses pairs of targets printed with relative focus offsets, by double exposure in one resist layer.
Abstract:
Described herein is a method for reducing apparatus performance variation. The method includes obtaining (i) a reference performance (e.g., CD) of a reference apparatus (e.g., a reference scanner), (ii) a set of initial leading degrees of freedom selected from a plurality of degrees of freedom of a plurality of pupil facet mirrors of an apparatus (e.g., to be matched scanner) that is selected to reproduce the reference performance, and (iii) exposure data related to one or more parameters (e.g., CD, overlay, focus, etc.) of the patterning process indicating a performance of the apparatus based on the set of initial leading degrees of freedom; and determining a matching pupil of the apparatus based on the set of initial leading degrees of freedom and the exposure data such that the matching pupil reduces a difference between the performance of the apparatus and the reference performance.
Abstract:
Described herein is a method for inspection of a patterning device. The method includes obtaining (i) patterning device apparatus data of a patterning device making process, (ii) a patterning device substrate map based on the patterning device apparatus data, and (iii) predicted process window limiting pattern locations corresponding to the patterning device based on the patterning device substrate map, and based on the process window limiting pattern locations, guiding, by a hardware computer system, a patterning device inspection apparatus to the process window limiting pattern locations for defect inspection.
Abstract:
A method including: obtaining a value of a characteristic of a physical item instance of a physical system or object, using a non-probabilistic model; obtaining an attribute of a distribution of a residue of the non-probabilistic model with respect to an ensemble of physical item instances that is based on an attribute of a distribution of a residue of the non-probabilistic model with respect to at least one physical item instance corresponding to at least one physical item type of the ensemble; determining an attribute of a distribution of the characteristic based on the attribute of the distribution of the residue with respect to an ensemble of physical item instances and on the value of the characteristic of the physical item instance; and determining a probability that the physical item instance is out of specification, based on the attribute of the distribution of the characteristic.