Abstract:
A method of determining overlay of a patterning process, the method including: illuminating a substrate with a radiation beam such that a beam spot on the substrate is filled with one or more physical instances of a unit cell, the unit cell having geometric symmetry at a nominal value of overlay; detecting primarily zeroth order radiation redirected by the one or more physical instances of the unit cell using a detector; and determining, by a hardware computer system, a non-nominal value of overlay of the unit cell from values of an optical characteristic of the detected radiation.
Abstract:
A method for assigning features into at least first features and second features, the first features being for at least one first patterning device configured for use in a lithographic process to form corresponding first structures on a substrate and the second features being for at least one second patterning device configured for use in a lithographic process to form corresponding second structures on a substrate, wherein the method including assigning the features into the first features and the second features based on a patterning characteristic of the features.
Abstract:
A method including: computing a value of a first variable of a pattern of, or for, a substrate processed by a patterning process by combining a fingerprint of the first variable on the substrate and a certain value of the first variable; and determining a value of a second variable of the pattern based at least in part on the computed value of the first variable.
Abstract:
A substrate has first and second target structures formed by a lithographic process. Each target structure has a two-dimensional periodic structure formed in a single layer using first and second lithographic steps. The first target structure has features defined in the second lithographic step displaced relative to features defined in the first lithographic step by a first bias amount. The second target structure has features defined in the second lithographic step displaced relative to features defined in the first lithographic step by a second bias amount. An angle-resolved scatter spectrum of the first target structure and an angle-resolved scatter spectrum of the second target structure is obtained. A measurement of a parameter of a lithographic process is derived from the measurements using asymmetry found in the scatter spectra of the first and second target structures.
Abstract:
A method of correcting an image characteristic of a substrate onto which one or more product features have been formed using a lithographic process, and an associated inspection apparatus method. The method includes measuring an error in the image characteristic of the substrate, and determining a correction for a subsequent formation of the product features based upon the measured error and a characteristic of one or more of the product feature(s).
Abstract:
A method of determining a parameter of a patterning process, the method including: obtaining a detected representation of radiation redirected by a structure having geometric symmetry at a nominal physical configuration, wherein the detected representation of the radiation was obtained by illuminating a substrate with a radiation beam such that a beam spot on the substrate was filled with the structure; and determining, by a hardware computer system, a value of the patterning process parameter based on optical characteristic values from an asymmetric optical characteristic distribution portion of the detected radiation representation with higher weight than another portion of the detected radiation representation, the asymmetric optical characteristic distribution arising from a different physical configuration of the structure than the nominal physical configuration.
Abstract:
A substrate has first and second target structures formed thereon by a lithographic process. Each target structure has two-dimensional periodic structure formed in a single material layer on a substrate using first and second lithographic steps, wherein, in the first target structure, features defined in the second lithographic step are displaced relative to features defined in the first lithographic step by a first bias amount that is close to one half of a spatial period of the features formed in the first lithographic step, and, in the second target structure, features defined in the second lithographic step are displaced relative to features defined in the first lithographic step by a second bias amount close to one half of said spatial period and different to the first bias amount. An angle-resolved scatter spectrum of the first target structure and an angle-resolved scatter spectrum of the second target structure is obtained, and a measurement of a parameter of a lithographic process is derived from the measurements using asymmetry found in the scatter spectra of the first and second target structures.
Abstract:
A method of evaluating a patterning process, the method including: obtaining the result of a first measurement of a first metrology target; obtaining the result of a second measurement of a second metrology target, the second metrology target having a structural difference from the first metrology target that generates a sensitivity difference and/or an offset, of a process parameter of the patterning process between the first and second metrology targets; and determining a value pertaining to the patterning process based on the results of the first and second measurements.
Abstract:
A method including: computing a value of a first variable of a pattern of, or for, a substrate processed by a patterning process by combining a fingerprint of the first variable on the substrate and a certain value of the first variable; and determining a value of a second variable of the pattern based at least in part on the computed value of the first variable.
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.