Abstract:
A method including determining a position of a first pattern in each of a plurality of target portions on a substrate, based on a fitted mathematical model, wherein the first pattern includes at least one alignment mark, wherein the mathematical model is fitted to a plurality of alignment mark displacements (dx, dy) for the alignment marks in the target portions, and wherein the alignment mark displacements are a difference between a respective nominal position of the alignment mark and measured position of the alignment mark; and transferring a second pattern onto each of the target portions, using the determined position of the first pattern in each of the plurality of target portions, wherein the mathematical model includes polynomials Z1 and Z2: Z1=r2 cos(2θ) and Z2=r2 sin(2θ) in polar coordinates (r, θ) or Z1=x2−y2 and Z2=xy in Cartesian coordinates (x, y).
Abstract:
A method including: determining first error information based on a first measurement and/or simulation result pertaining to a first patterning device in a patterning system; determining second error information based on a second measurement and/or simulation result pertaining to a second patterning device in the patterning system; determining a difference between the first error information and the second error information; and creating modification information for the first patterning device and/or the second patterning device based on the difference between the first error information and the second error information, wherein the difference between the first error information and the second error information is reduced to within a certain range after the first patterning device and/or the second patterning device is modified according to the modification information.
Abstract:
A lithography system configured to apply a pattern to a substrate, the system including a lithography apparatus configured to expose a layer of the substrate according to the pattern, and a machine learning controller configured to control the lithography system to optimize a property of the pattern, the machine learning controller configured to be trained on the basis of a property measured by a metrology unit configured to measure the property of the exposed pattern in the layer and/or a property associated with exposing the pattern onto the substrate, and to correct lithography system drift by adjusting one or more selected from: the lithography apparatus, a track unit configured to apply the layer on the substrate for lithographic exposure, and/or a control unit configured to control an automatic substrate flow among the track unit, the lithography apparatus, and the metrology unit.
Abstract:
An apparatus and method for performing a measurement operation on a substrate in accordance with one or more substrate alignment models. The one or more substrate alignment models are selected from a plurality of candidate substrate alignment models. The apparatus, which may be a lithographic apparatus, includes an external interface which enables selection of the substrate alignment model(s) and/or alteration of the substrate alignment model(s) prior to the measurement operation.
Abstract:
A method of measuring a parameter of a lithographic process, the method including: illuminating a diffraction measurement target on a substrate with radiation, the measurement target including at least a first sub-target, at least a second sub-target and at least third sub-target, wherein the first, second and third sub-targets each include a periodic structure and wherein the first sub-target, second sub-target and third sub-target each have a different design and wherein at least two of the sub-targets are respectively designed for determination of a different lithographic process parameter; and detecting radiation scattered by the at least two sub-targets to obtain for that target a measurement representing the different parameters of the lithographic process.
Abstract:
A reticle is loaded into a lithographic apparatus. The apparatus performs measurements on the reticle, so as to calculate alignment parameters for transferring the pattern accurately to substrates. Tests are performed to detect possible contamination of the reticle or its support. Either operation proceeds with a warning, or the patterning of substrates is stopped. The test uses may use parameters of the alignment model itself, or different parameters. The integrity parameters may be compared against reference values reflecting historic measurements, so that sudden changes in a parameter are indicative of contamination. Integrity parameters may be calculated from residuals of the alignment model. In an example, height residuals are used to calculate parameters of residual wedge (Rx′) and residual roll (Ryy′). From these, integrity parameters expressed as height deviations are calculated and compared against thresholds.
Abstract:
A method of determining a control setting for a lithographic apparatus. The method includes obtaining a first correction for a current layer on a current substrate based on first metrology data associated with one or more previous substrates, and obtaining a second correction for the current layer on the current substrate. The second correction is based on a residual determined based on second metrology data associated with a previous layer on the current substrate. The method further includes determining the control setting for the lithographic apparatus for patterning the current layer on the current substrate by combining the first correction and the second correction.
Abstract:
Performance measurement targets are used to measure performance of a lithographic process after processing a number of substrates. In a set-up phase, the method selects an alignment mark type and alignment recipe from among a plurality of candidate mark types by reference to expected parameters of the patterning process. After exposing a number of test substrates using the patterning process, a preferred metrology target type and metrology recipe are selected by comparing measured performance (e.g. overlay) of performance of the patterning process measured by a reference technique. Based on the measurements of position measurement marks and performance measurement targets after actual performance of the patterning process, the alignment mark type and/or recipe may be revised, thereby co-optimizing the alignment marks and metrology targets. Alternative run-to-run feedback strategies may also be compared during subsequent operation of the process.
Abstract:
A lithographic apparatus applies a pattern repeatedly to target portions across a substrate. Prior to applying the pattern an alignment sensor measures positions of marks in the plane of the substrate and a level sensor measures height deviations in a direction normal to the plane of the substrate. The apparatus applies the pattern to the substrate while positioning the applied pattern using the positions measured by the alignment sensor and using the height deviations measured by the level sensor. The apparatus is further arranged to calculate and apply corrections in the positioning of the applied pattern, based on derivatives of the measured height deviations. The corrections may be calculated on an intrafield and/or interfield basis. The corrections may be based on changes between the observed height deviations and height deviations measured previously on the same substrate.
Abstract:
A method for analyzing a process, the method including obtaining a multi-dimensional probability density function representing an expected distribution of values for a plurality of process parameters; obtaining a performance function relating values of the process parameters to a performance metric of the process; and using the performance function to map the probability density function to a performance probability function having the process parameters as arguments.