Abstract: A target structure such as an alignment mark on a semiconductor substrate becomes obscured by an opaque layer so that it cannot be located by an alignment sensor. A position for the mark is determined using an edge position sensor and relative position information that defines the position of the mark relative to one or more edge portions of the substrate is stored prior to formation of the opaque layer. A window can be opened in the opaque layer, based on the determined position. After revealing the target structure, the alignment sensor can, if desired, measure more accurately the position of the target structure, for use in controlling a further lithographic step. The edge position sensor may be a camera having an angle-selective behavior. The edge position sensor may be integrated within the alignment sensor hardware.

Abstract: In a method of controlling a lithographic apparatus, historical performance measurements are used to calculate a process model relating to a lithographic process. Current positions of a plurality of alignment marks provided on a current substrate are measured and used to calculate a substrate model relating to a current substrate. Additionally, historical position measurements obtained at the time of processing the prior substrates are used with the historical performance measurements to calculate a model mapping. The model mapping is applied to modify the substrate model. The lithographic apparatus is controlled using the process model and the modified substrate model together. Overlay performance is improved by avoiding over- or under-correction of correlated components of the process model and the substrate model. The model mapping may be a subspace mapping, and dimensionality of the model mapping may be reduced, before it is used.

Abstract: A method for determining one or more optimized values of an operational parameter of a sensor system configured to measure a property of a substrate is disclosed. The method includes: determining a quality parameter for a plurality of substrates; determining measurement parameter values for the plurality of substrates using the sensor system for a plurality of values of the operational parameter; comparing a substrate to substrate variation of the quality parameter and a substrate to substrate variation of a mapping of the measurement parameter values; and determining the one or more optimized values of the operational parameter based on the comparing.

Abstract: A lithographic apparatus has a substrate table on which a substrate is positioned, and an alignment sensor used to measure the alignment of the substrate. In an exemplary processing method, the alignment sensor is used to perform one or more edge measurements in a first step. In a second step, one or more edge measurements are performed on the notch of the substrate. The edge measurements are then used to align the substrate in the lithographic apparatus. In a particular example, the substrate is arranged relative to the alignment sensor such that a portion of the edge surface is positioned at the focal length of the lens. When the alignment sensor detects radiation scattered by the edge surface at the focal length of the lens, the presence of the edge of the substrate is detected.

Abstract: A pattern formed on a substrate includes first and second sub-patterns positioned adjacent one another and having respective first and second periodicities. The pattern is observed to obtain a combined signal which includes a beat component having a third periodicity at a frequency lower than that of the first and second periodicities. A measurement of performance of the lithographic process is determined by reference to a phase of the beat component. Depending how the sub-patterns are formed, the performance parameter might be critical dimension (CD) or overlay, for example. For CD measurement, one of the sub-patterns may comprise marks each having of a portion sub-divided by product-like features. The measurement can be made using an existing alignment sensor of a lithographic apparatus. Sensitivity and accuracy of the measurement can be adjusted by selection of the first and second periodicities, and hence the third periodicity.

Abstract: A method of characterizing a deformation of a plurality of substrates is described. The method comprising the steps of: —measuring, for a plurality of n different alignment measurement parameters ? and for a plurality of substrates, a position of the alignment marks; —determining a positional deviation as the difference between the n alignment mark position measurements and a nominal alignment mark position; —grouping the positional deviations into data sets; —determining an average data set; —subtracting the average data set from the data sets to obtain a plurality of variable data sets; —performing a blind source separation method on the variable data sets, thereby decomposing the variable data sets into a set of eigenwafers representing principal components of the variable data sets; —subdividing the set of eigenwafers into a set of mark deformation eigenwafers and a set of substrate deformation eigenwafers.

Abstract: A lithographic apparatus is described, the apparatus comprising: an illumination system configured to condition a radiation beam; a support constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam; a substrate table constructed to hold a substrate; and a projection system configured to project the patterned radiation beam onto a target portion of the substrate, wherein the apparatus further comprises an alignment system configured to perform, for one or more alignment marks that are present on the substrate: —a plurality of alignment mark position measurements for the alignment mark by applying a respective plurality of different alignment measurement parameters, thereby obtaining a plurality of measured alignment mark positions for the alignment mark; the apparatus further comprising a processing unit, the processing unit being configured to: —determine, for each of the plurality of a

Abstract: A lithographic apparatus is described, the apparatus comprising: an illumination system configured to condition a radiation beam; a support constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam; a substrate table constructed to hold a substrate; and a projection system configured to project the patterned radiation beam onto a target portion of the substrate, wherein the apparatus further comprises an alignment system configured to perform, for one or more alignment marks that are present on the substrate: —a plurality of alignment mark position measurements for the alignment mark by applying a respective plurality of different alignment measurement parameters, thereby obtaining a plurality of measured alignment mark positions for the alignment mark; the apparatus further comprising a processing unit, the processing unit being configured to: —determine, for each of the plurality of a

Abstract: A measurement apparatus including an optical system to provide illumination radiation into a spot on a periodic structure and to receive radiation redirected by the periodic structure, the optical system including a first stop to block zero order radiation from the periodic structure and allow non-zero order radiation to pass, and a second stop to block zero order radiation passing the first stop and to allow the non-zero order radiation to pass, and a radiation detector, downstream of the optical system, to receive the non-zero order radiation.

Abstract: A substrate is provided with device structures and metrology structures (800). The device structures include materials exhibiting inelastic scattering of excitation radiation of one or more wavelengths. The device structures include structures small enough in one or more dimensions that the characteristics of the inelastic scattering are influenced significantly by quantum confinement. The metrology structures (800) include device-like structures (800b) similar in composition and dimensions to the device features, and calibration structures (800a). The calibration structures are similar to the device features in composition but different in at least one dimension. Using an inspection apparatus and method implementing Raman spectroscopy, the dimensions of the device-like structures can be measured by comparing spectral features of radiation scattered inelastically from the device-like structure and the calibration structure.

Abstract: A measurement apparatus including an optical system to provide illumination radiation into a spot on a periodic structure and to receive radiation redirected by the periodic structure, the optical system including a first stop to block zero order radiation from the periodic structure and allow non-zero order radiation to pass, and a second stop to block zero order radiation passing the first stop and to allow the non-zero order radiation to pass, and a radiation detector, downstream of the optical system, to receive the non-zero order radiation.

Abstract: A patterning device, for use in forming a marker on a substrate by optical projection, the patterning device including a marker pattern having a density profile that is periodic with a fundamental spatial frequency corresponding to a desired periodicity of the marker to be formed. The density profile is modulated (such as sinusoidally) so as to suppress one or more harmonics of the fundamental frequency, relative to a simple binary profile having the fundamental frequency.

Abstract: A method to determine the usefulness of an alignment mark of a first pattern in transferring a second pattern to a substrate relative to the first pattern already present on the substrate includes measuring the position of the alignment mark, modeling the position of the alignment mark, determining the model error between measured and modeled position, measuring a corresponding overlay error between first and second pattern and comparing the model error with the overlay error to determine the usefulness of the alignment mark. Subsequently this information can be used when processing next substrates thereby improving the overlay for these substrates. A lithographic apparatus and/or overlay measurement system may be operated in accordance with the method.

Abstract: Position and curvature information of a patterning device may be determined directly from the patterning device and controlled based on the determined information. In an embodiment, a lithographic apparatus includes a position determining system operative to determine a relative position of the patterning device. The patterning device may be configured to create a patterned radiation beam from a radiation beam incident on a major surface of the patterning device. The patterning device may have a side surface having an edge in common with the major surface. The position determining system may include an interferometer operative to transmit light to the side surface and to receive the transmitted light after the transmitted light has been reflected at the side surface. The position determining system is operative to determine a quantity representative of the relative position of the patterning device from the received reflected transmitted light.

Abstract: A substrate is provided with device structures and metrology structures (800). The device structures include materials exhibiting inelastic scattering of excitation radiation of one or more wavelengths. The device structures include structures small enough in one or more dimensions that the characteristics of the inelastic scattering are influenced significantly by quantum confinement. The metrology structures (800) include device-like structures (800b) similar in composition and dimensions to the device features, and calibration structures (800a). The calibration structures are similar to the device features in composition but different in at least one dimension. Using an inspection apparatus and method implementing Raman spectroscopy, the dimensions of the device-like structures can be measured by comparing spectral features of radiation scattered inelastically from the device-like structure and the calibration structure.

Abstract: An alignment measurement system measures an alignment target on an object. A measurement illuminates the target and is reflected. The reflected measurement beam is split and its parts are differently polarized. A detector receives the reflected measurement beam. A processing unit determines alignment on the basis of the measurement beam received by the detector. An alternative arrangement utilizes an optical dispersive fiber to guide a multi-wavelength measurement beam reflected from the object to a detector.

Abstract: An alignment measurement system measures an alignment target on an object. A measurement illuminates the target and is reflected. The reflected measurement beam is split and its parts are differently polarized. A detector receives the reflected measurement beam. A processing unit determines alignment on the basis of the measurement beam received by the detector. An alternative arrangement utilizes an optical dispersive fiber to guide a multi-wavelength measurement beam reflected from the object to a detector.

Abstract: An alignment measurement system measures an alignment target on an object. A measurement illuminates the target and is reflected. The reflected measurement beam is split and its parts are differently polarized. A detector receives the reflected measurement beam. A processing unit determines alignment on the basis of the measurement beam received by the detector. An alternative arrangement utilizes an optical dispersive fiber to guide a multi-wavelength measurement beam reflected from the object to a detector.

Abstract: A method to determine the usefulness of an alignment mark of a first pattern in transferring a second pattern to a substrate relative to the first pattern already present on the substrate includes measuring the position of the alignment mark, modeling the position of the alignment mark, determining the model error between measured and modeled position, measuring a corresponding overlay error between first and second pattern and comparing the model error with the overlay error to determine the usefulness of the alignment mark. Subsequently this information can be used when processing next substrates thereby improving the overlay for these substrates. A lithographic apparatus and/or overlay measurement system may be operated in accordance with the method.

Abstract: A method is used to estimate a value representative for a level of alignment mark deformation on a processed substrate using an alignment system. The alignment sensor system is able to emit light at different measuring frequencies to reflect from an alignment mark on the substrate and to detect a diffraction pattern in the reflected light in order to measure an alignment position of the alignment mark. The two or more measuring frequencies are used to measure an alignment position deviation per alignment mark associated with each of the two or more measuring frequencies relative to an expected predetermined alignment position of the alignment mark. A value is determined representative for the spread in the determined alignment position deviations per alignment mark in order to estimate the level of alignment mark deformation.