Systems, apparatuses, and methods are provided for correcting the detected positions of alignment marks disposed on a substrate and aligning the substrate using the corrected data to accurately expose patterns on the substrate. An example method can include receiving a measurement signal including a combined intensity signal corresponding to first and second diffracted light beams diffracted from first and second alignment targets having different orientations. The example method can further include fitting the combined intensity signal using templates to determine weight values and determining, based on the templates and weight values, first and second intensity sub-signals corresponding to the first and second diffracted light beams. The method can further include determining first and second intensity imbalance signals based on the first and second intensity sub-signals and determining a set of corrections to the measurement signal based on the first and second intensity imbalance signals.

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 alignment mark position measurements, a positional deviation as a difference between an expected alignment mark position and a measured alignment mark position, the measured alignment mark position being determined based on the respective alignment mark position measurement; define a set of functions as possible causes for the positional deviations, the set of functions including a substrate deformation function representing a deformation of the substrate, and at least one mark deformation function representing a deformation of the one or more alignment marks; generating a matrix equation PD=M*F whereby a vector PD comprising the positional deviations is set equal to a weighted combination, represented by a weight coefficient matrix M, of a vector F comprising the substrate deformation function and the at least one mark deformation function, whereby weight coefficients associated with the at least one mark deformation function vary depending on applied alignment measurement; determining a value for the weight coefficients of the matrix M; determining an inverse or pseudo-inverse matrix of the matrix M, thereby obtaining a value for the substrate deformation function as a weighted combination of the positional deviations. applying the value of the substrate deformation function to perform an alignment of the target portion with the patterned radiation beam.

A metrology system includes a radiation source that generates light, an optical modulation unit, a reflector, an interferometer, and a detector. The optical modulating unit temporally separates a first polarization mode of the light from a second polarization mode of the light. The reflector directs the light towards a substrate. The interferometer interferes the diffracted light from a pattern on the substrate, or reflected light from the substrate, and produces output light from the interference. The detector receives the output light from the interferometer. The first and second polarization modes of the output light are temporally separated at the detector.

An inspection apparatus (for example a scatterometer) comprises: a substrate support for supporting a substrate and an optical system. An illumination system illuminates a target (T) with radiation. A positioning system (518) moves one or both of the optical system and the substrate support so as to position an individual target (T) relative to the optical system so that the imaging optics can use a portion of the diffracted radiation to form an image of the target structure on an image sensor (23). A liquid lens (722) is controlled (902) by feed-forward control to maintain said image stationary against vibration and/or scanning movement between the optical system and the target structure. In a second aspect, a liquid lens (1324, 1363) to correct chromatic aberration during measurements made at different wavelengths. This may improve focusing of the illumination on the target (T), and/or focusing of an image on the image sensor (23).

Disclosed is a metrology apparatus and method for measuring a structure formed on a substrate by a lithographic process. The metrology apparatus comprises an illumination system operable to provide measurement radiation comprising a plurality of wavelengths; and a hyperspectral imager operable to obtain a hyperspectral representation of a measurement scene comprising the structure, or a part thereof, from scattered measurement radiation subsequent to the measurement radiation being scattered by the structure.

Target structures such as overlay gratings (Ta and Tb) are formed on a substrate (W) by a lithographic process. The first target is illuminated with a spot of first radiation (456a, Sa) and simultaneously the second target is illuminated with a spot of second radiation (456b, Sb). A sensor (418) detects at different locations, portions (460x, 460x+) of said first radiation that have been diffracted in a first direction by features of the first target and portions (460y, 460y+) of said second radiation that have been diffracted in a second direction by features of the second target. Asymmetry in X and Y directions can be detected simultaneously, reducing the time required for overlay measurements in X and Y. The two spots of radiation at soft x-ray wavelength can be generated simply by exciting two locations (710a, 710b) in a higher harmonic generation (HHG) radiation source or inverse Compton scattering source.

A detection system (200) includes an illumination system (210), a first optical system (232), a phase modulator (220), a lock-in detector (255), and a function generator (230). The illumination system is configured to transmit an illumination beam (218) along an illumination path. The first optical system is configured to transmit the illumination beam toward a diffraction target (204) on a substrate (202). The first optical system is further configured to transmit a signal beam including diffraction order sub-beams (222, 224, 226) that are diffracted by the diffraction target. The phase modulator is configured to modulate the illumination beam or the signal beam based on a reference signal. The lock-in detector is configured to collect the signal beam and to measure a characteristic of the diffraction target based on the signal beam and the reference signal. The function generator is configured to generate the reference signal for the phase modulator and the lock-in detector.

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 alignment mark position measurements, a positional deviation as a difference between an expected alignment mark position and a measured alignment mark position, the measured alignment mark position being determined based on the respective alignment mark position measurement; define a set of functions as possible causes for the positional deviations, the set of functions including a substrate deformation function representing a deformation of the substrate, and at least one mark deformation function representing a deformation of the one or more alignment marks; generating a matrix equation PD=M*F whereby a vector PD comprising the positional deviations is set equal to a weighted combination, represented by a weight coefficient matrix M, of a vector F comprising the substrate deformation function and the at least one mark deformation function, whereby weight coefficients associated with the at least one mark deformation function vary depending on applied alignment measurement; determining a value for the weight coefficients of the matrix M; determining an inverse or pseudo-inverse matrix of the matrix M, thereby obtaining a value for the substrate deformation function as a weighted combination of the positional deviations. applying the value of the substrate deformation function to perform an alignment of the target portion with the patterned radiation beam.

A measurement system is disclosed in which a first optical system splits an input radiation beam into a plurality of components. A modulator receives the plurality of components and applies a modulation to at least one of the components independently of at least one other of the components. A second optical system illuminates a target with the plurality of components and directs radiation scattered by the target to a detection system. The detection system distinguishes between each of one or more components, or between each of one or more groups of components, of the radiation directed to the detection system based on the modulation applied to each component or each group of components by the modulator.

A system 100 for enabling interactive annotation of an image 102, comprising a user input 160 for receiving a placement command 162 from a user, the placement command being indicative of a first placement location of a marker 140 in the image 102, and a processor 180 arranged for (i) applying an image processing algorithm to a region 130 in the image, the region being based on the first placement location, and the image processing algorithm being responsive to image portions which visually correspond to the marker 140 for establishing a plurality of match degrees between, on the one hand, the marker, and, on the other hand, a plurality of image portions within the region, (ii) establishing a second placement location in dependence on the plurality of match degrees and the respective plurality of image portions for matching the marker 140 to the region in the image, and (iii) placing the marker 140 at the second placement location in the image 102.