Abstract: Disclosed is a method and associated apparatus for measuring a characteristic of interest relating to a structure on a substrate. The method comprises calculating a value for the characteristic of interest directly from the effect of the characteristic of interest on at least the phase of illuminating radiation when scattered by the structure, subsequent to illuminating said structure with said illuminating radiation.

Abstract: A method provides the steps of receiving an image from a metrology tool, determining individual units of said image and discriminating the units which provide accurate metrology values. The images are obtained by measuring the metrology target at multiple wavelengths. The discrimination between the units, when these units are pixels in said image, is based on calculating a degree of similarity between said units.

Abstract: A method includes obtaining, for each particular feature of a plurality of features of a device pattern of a substrate being created using a patterning process, a modelled or simulated relation of a parameter of the patterning process between a measurement target for the substrate and the particular feature; and based on the relation and measured values of the parameter from the metrology target, generating a distribution of the parameter across at least part of the substrate for each of the features, the distribution for use in design, control or modification of the patterning process.

Abstract: Disclosed is a method and associated apparatus for measuring a characteristic of interest relating to a structure on a substrate. The method comprises calculating a value for the characteristic of interest directly from the effect of the characteristic of interest on at least the phase of illuminating radiation when scattered by the structure, subsequent to illuminating said structure with said illuminating radiation.

Abstract: A method includes obtaining, for each particular feature of a plurality of features of a device pattern of a substrate being created using a patterning process, a modelled or simulated relation of a parameter of the patterning process between a measurement target for the substrate and the particular feature; and based on the relation and measured values of the parameter from the metrology target, generating a distribution of the parameter across at least part of the substrate for each of the features, the distribution for use in design, control or modification of the patterning process.

Abstract: Disclosed is a method and associated apparatus for measuring a characteristic of interest relating to a structure on a substrate. The method comprises calculating a value for the characteristic of interest directly from the effect of the characteristic of interest on at least the phase of illuminating radiation when scattered by the structure, subsequent to illuminating said structure with said illuminating radiation.

Abstract: A method includes obtaining, for each particular feature of a plurality of features of a device pattern of a substrate being created using a patterning process, a modelled or simulated relation of a parameter of the patterning process between a measurement target for the substrate and the particular feature; and based on the relation and measured values of the parameter from the metrology target, generating a distribution of the parameter across at least part of the substrate for each of the features, the distribution for use in design, control or modification of the patterning process.

Abstract: An overlay metrology target (600, 900, 1000) contains a plurality of overlay gratings (932-935) formed by lithography. First diffraction signals (740(1)) are obtained from the target, and first asymmetry values (As) for the target structures are derived. Second diffraction signals (740(2)) are obtained from the target, and second asymmetry values (As?) are derived. The first and second diffraction signals are obtained using different capture conditions and/or different designs of target structures and/or bias values. The first asymmetry signals and the second asymmetry signals are used to solve equations and obtain a measurement of overlay error. The calculation of overlay error makes no assumption whether asymmetry in a given target structure results from overlay in the first direction, in a second direction or in both directions. With a suitable bias scheme the method allows overlay and other asymmetry-related properties to be measured accurately, even in the presence of two-dimensional overlay structure.

Abstract: Disclosed is a process monitoring method, and an associated metrology apparatus.

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: An overlay metrology target (600, 900, 1000) contains a plurality of overlay gratings (932-935) formed by lithography. First diffraction signals (740(1)) are obtained from the target, and first asymmetry values (As) for the target structures are derived. Second diffraction signals (740(2)) are obtained from the target, and second asymmetry values (As?) are derived. The first and second diffraction signals are obtained using different capture conditions and/or different designs of target structures and/or bias values. The first asymmetry signals and the second asymmetry signals are used to solve equations and obtain a measurement of overlay error. The calculation of overlay error makes no assumption whether asymmetry in a given target structure results from overlay in the first direction, in a second direction or in both directions. With a suitable bias scheme the method allows overlay and other asymmetry-related properties to be measured accurately, even in the presence of two-dimensional overlay structure.

Abstract: A method of measuring a property of a substrate, the substrate having a plurality of targets formed thereon, the method comprising: measuring N targets of the plurality of targets using an optical measurement system, where N is an integer greater than 2 and each of said N targets is measured Wt times, where Wt is an integer greater than 2 so as to obtain N*Wt measurement values; and determining R property values using Q equations and the N*Wt measurement values, where R<Q?N*Wt; wherein the optical measurement system has at least one changeable setting and, for each of the N targets, measurement values are obtained using different setting values of at least one changeable setting.

Abstract: Disclosed is a method and associated apparatus for measuring a characteristic of interest relating to a structure on a substrate. The method comprises calculating a value for the characteristic of interest directly from the effect of the characteristic of interest on at least the phase of illuminating radiation when scattered by the structure, subsequent to illuminating said structure with said illuminating radiation.

Abstract: Disclosed is a process monitoring method, and an associated metrology apparatus.

Abstract: Disclosed is a process monitoring method, and an associated metrology apparatus. The method comprises: comparing measured target response spectral sequence data relating to the measurement response of actual targets to equivalent reference target response sequence data relating to a measurement response of the targets as designed; and performing a process monitoring action based on the comparison of said measured target response sequence data and reference target response sequence data. The method may also comprise determining stack parameters from the measured target response spectral sequence data and reference target response spectral sequence data.

Abstract: An overlay metrology target (600, 900, 1000) contains a plurality of overlay gratings (932-935) formed by lithography. First diffraction signals (740(1)) are obtained from the target, and first asymmetry values (As) for the target structures are derived. Second diffraction signals (740(2)) are obtained from the target, and second asymmetry values (As?) are derived. The first and second diffraction signals are obtained using different capture conditions and/or different designs of target structures and/or bias values. The first asymmetry signals and the second asymmetry signals are used to solve equations and obtain a measurement of overlay error. The calculation of overlay error makes no assumption whether asymmetry in a given target structure results from overlay in the first direction, in a second direction or in both directions. With a suitable bias scheme the method allows overlay and other asymmetry-related properties to be measured accurately, even in the presence of two-dimensional overlay structure.

Abstract: Disclosed is a process monitoring method, and an associated metrology apparatus. The method comprises: comparing measured target response spectral sequence data relating to the measurement response of actual targets to equivalent reference target response sequence data relating to a measurement response of the targets as designed; and performing a process monitoring action based on the comparison of said measured target response sequence data and reference target response sequence data. The method may also comprise determining stack parameters from the measured target response spectral sequence data and reference target response spectral sequence data.

Abstract: A method of measuring a property of a substrate, the substrate having a plurality of targets formed thereon, the method comprising: measuring N targets of the plurality of targets using an optical measurement system, where N is an integer greater than 2 and each of said N targets is measured Wt times, where Wt is an integer greater than 2 so as to obtain N*Wt measurement values; and determining R property values using Q equations and the N*Wt measurement values, where R<Q?N*Wt; wherein the optical measurement system has at least one changeable setting and, for each of the N targets, measurement values are obtained using different setting values of at least one changeable setting.