Abstract: A method and apparatus to measure overlay from images of metrology targets, images obtained using acoustic waves, for example images obtained using an acoustic microscope. The images of two targets are obtained, one image using acoustic waves and one image using optical waves, the edges of the images are determined and overlay between the two targets is obtained as the difference between the edges of the two images.

Abstract: Methods of measuring a target formed by a lithographic process, a metrology apparatus and a polarizer assembly are disclosed. The polarizer assembly comprises a polarizing structure having a substantially planar form and configured to polarize radiation passing there through in a circular polarizing region. The circular polarizing region is configured to apply a first polarization to radiation passing through a first one of two pairs of diametrically opposite quadrants of the circular polarizing region and to apply a second polarization, orthogonal to the first polarization, to radiation passing through a second one of two pairs of diametrically opposite quadrants of the circular polarizing region.

Abstract: Disclosed is a metrology apparatus for measuring a parameter of a lithographic process, and associated computer program and method. The metrology apparatus comprises an optical system for measuring a target on a substrate by illuminating the target with measurement radiation and detecting the measurement radiation scattered by the target; and an array of lenses. Each lens of the array is operable to focus the scattered measurement radiation onto a sensor, said array of lenses thereby forming an image on the sensor which comprises a plurality of sub-images, each sub-image being formed by a corresponding lens of the array of lenses. The resulting plenoptic image comprises image plane information from the sub-images, wavefront distortion information (from the relative positions of the sub-images) and pupil information from the relative intensities of the sub-images.

Abstract: Methods and apparatuses for measuring a plurality of structures formed on a substrate are disclosed. In one arrangement, a method includes obtaining data from a first measurement process. The first measurement process including individually measuring each of the plurality of structures to measure a first property of the structure. A second measurement process is used to measure a second property of each of the plurality of structures. The second measurement process includes illuminating each structure with radiation having a radiation property that is individually selected for that structure using the measured first property for the structure.

Abstract: Measurement system comprising a radiation source configured to generate a measurement radiation beam, a polarizer and a grating to receive the measurement radiation beam and provide a polarized measurement radiation beam patterned by the grating, optics to form an image of the grating at a target location on a substrate. The image comprises a first part having a first polarization and a second part having a second polarization, detection optics to receive radiation from the target location of the substrate and form an image of the grating image at a second grating, and a detector to receive radiation transmitted through the second grating and produce a two output signal indicative of the intensity of the transmitted radiation for the first and second parts of the grating image respectively. Topography of the substrate can be determined from the signals.

Abstract: A topography measurement system comprising a radiation source configured to generate a radiation beam, a spatially coded grating configured to pattern the radiation beam and thereby provide a spatially coded radiation beam, optics configured to form an image of the spatially coded grating at a target location on a substrate, detection optics configured to receive radiation reflected from the target location of the substrate and form an image of the grating image at a second grating, and a detector configured to receive radiation transmitted through the second grating and produce an output signal.

Abstract: A lithographic apparatus comprises comprise a substrate table constructed to hold a substrate; and a sensor configured to sense a position of an alignment mark provided onto the substrate held by the substrate table. The sensor comprises a source of radiation configured to illuminate the alignment mark with a radiation beam, a detector configured to detect the radiation beam, having interacted with the alignment mark, as an out of focus optical pattern, and a data processing system. The data processing system is configured to receive image data representing the out of focus optical pattern, and process the image data for determining alignment information, comprising applying a lensless imaging algorithm to the out of focus optical pattern.

Abstract: An inspection apparatus, method, and system are described herein. An example inspection apparatus includes an optical system and an imaging system. The optical system may be configured to output an illumination beam incident on a target including one or more features, the illumination beam polarized with a first polarization when incident on the target. The imaging system may be configured to obtain intensity data representing at least a portion of the illumination beam scattered by the one or more features, where the portion of the illumination beam has a second polarization orthogonal to the first polarization. The inspection apparatus may be further configured to generate image data representing an image of each of the feature(s) based on the intensity data, and determine a measurement of a parameter of interest associated with the feature(s) based on an amount of the portion of the illumination beam having the second polarization.

Abstract: A scatterometer performs diffraction based measurements of one or more parameters of a target structure. To make two-color measurements in parallel, the structure is illuminated simultaneously with first radiation (302) having a first wavelength and a first angular distribution and with second radiation (304) having a second wavelength and a second angular distribution. The collection path (CP) includes a segmented wavelength-selective filter (21, 310) arranged to transmit wanted higher order portions of the diffracted first radiation (302X, 302Y) and of the diffracted second radiation (304X, 304Y), while simultaneously blocking zero order portions (302?, 304?) of both the first radiation and second radiation.

Abstract: Methods of measuring a target formed by a lithographic process, a metrology apparatus and a polarizer assembly are disclosed. The target comprises a layered structure having a first periodic structure in a first layer and a second periodic structure in a second layer. The target is illuminated with polarized measurement radiation. Zeroth order scattered radiation from the target is detected. An asymmetry in the first periodic structure is derived using the detected zeroth order scattered radiation from the target. A separation between the first layer and the second layer is such that the detected zeroth order scattered radiation is independent of overlay error between the first periodic structure and the second periodic structure. The derived asymmetry in the first periodic structure is used to derive the correct overlay value between the first periodic structure and the second periodic structure.

Abstract: Methods and apparatuses for measuring a plurality of structures formed on a substrate are disclosed. In one arrangement, a method includes obtaining data from a first measurement process. The first measurement process including individually measuring each of the plurality of structures to measure a first property of the structure. A second measurement process is used to measure a second property of each of the plurality of structures. The second measurement process includes illuminating each structure with radiation having a radiation property that is individually selected for that structure using the measured first property for the structure.

Abstract: Disclosed is a metrology apparatus for measuring a parameter of a lithographic process, and associated computer program and method. The metrology apparatus comprises an optical system for measuring a target on a substrate by illuminating the target with measurement radiation and detecting the measurement radiation scattered by the target; and an array of lenses. Each lens of the array is operable to focus the scattered measurement radiation onto a sensor, said array of lenses thereby forming an image on the sensor which comprises a plurality of sub-images, each sub-image being formed by a corresponding lens of the array of lenses. The resulting plenoptic image comprises image plane information from the sub-images, wavefront distortion information (from the relative positions of the sub-images) and pupil information from the relative intensities of the sub-images.

Abstract: The disclosure relates to methods of determining a value of a parameter of interest of a patterning process, and of cleaning a signal containing information about the parameter of interest. In one arrangement, first and second detected representations of radiation are obtained. The radiation is provided by redirection of polarized incident radiation by a structure. The first and second detected representations are derived respectively from first and second polarization components of the redirected radiation. An asymmetry in the first detected representation comprises a contribution from the parameter of interest and a contribution from one or more other sources of asymmetry. An asymmetry in the second detected representation comprises a larger contribution from said one or more other sources of asymmetry relative to a contribution from the parameter of interest. A combination of the first and second detected representations is used to determine a value of the parameter of interest.

Abstract: An acoustic scatterometer 502 has an acoustic source 520 operable to project acoustic radiation 526 onto a periodic structure 538 and 540 formed on a substrate 536. An acoustic detector 518 is operable to detect the ?1st acoustic diffraction order 528 diffracted by the periodic structure 538 and 540 while discriminating from specular reflection (0th order 532). Another acoustic detector 522 is operable to detect the +1st acoustic diffraction order 530 diffracted by the periodic structure, again while discriminating from the specular reflection (0th order 532). The acoustic source and acoustic detector may be piezo transducers. The angle of incidence of the projected acoustic radiation 526 and location of the detectors 518 and 522 are arranged with respect to the periodic structure 538 and 540 such that the detection of the ?1st and +1st acoustic diffraction orders 528 and 530 discriminates from the 0th order specular reflection 532.

Abstract: A metrology apparatus is disclosed that has an optical system to focus radiation onto a structure and directs redirected radiation from the structure to a detection system. The optical system applies a plurality of different offsets of an optical characteristic to radiation before and/or after redirected by the structure, such that a corresponding plurality of different offsets are provided to redirected radiation derived from a first point of a pupil plane field distribution relative to redirected radiation derived from a second point of the pupil plane field distribution. The detection system detects a corresponding plurality of radiation intensities resulting from interference between the redirected radiation derived from the first point of the pupil plane field distribution and the redirected radiation derived from the second point of the pupil plane field distribution. Each radiation intensity corresponds to a different one of the plurality of different offsets.

Abstract: Described is a metrology system for determining a characteristic of interest relating to at least one structure on a substrate, and associated method. The metrology system comprises a processor being configured to computationally determine phase and amplitude information from a detected characteristic of scattered radiation having been reflected or scattered by the at least one structure as a result of illumination of said at least one structure with illumination radiation in a measurement acquisition, and use the determined phase and amplitude to determine the characteristic of interest.

Abstract: An inspection apparatus, including: an objective configured to receive diffracted radiation from a metrology target having positive and negative diffraction order radiation; an optical element configured to separate the diffracted radiation into portions separately corresponding to each of a plurality of different values or types of one or more radiation characteristics and separately corresponding to the positive and negative diffraction orders; and a detector system configured to separately and simultaneously measure the portions.

Abstract: Devices and methods for processing a radiation beam with coherence are disclosed. In one arrangement, an optical system receives a radiation beam with coherence. The radiation beam comprises components distributed over one or more radiation beam spatial modes. A waveguide supports a plurality of waveguide spatial modes. The optical system directs a plurality of the components of the radiation beam belonging to a common radiation beam spatial mode and having different frequencies onto the waveguide in such a way that each of the plurality of components couples to a different set of the waveguide spatial modes, each set comprising one or more of the waveguide spatial modes.

Abstract: A method comprising: evaluating a plurality of polarization characteristics associated with measurement of a metrology target of a substrate processed using a patterning process, against one or more measurement quality parameters; and selecting one or more polarization characteristics from the plurality of polarization characteristics based on one or more of the measurement quality parameters

Abstract: A method and apparatus to measure overlay from images of metrology targets, images obtained using acoustic waves, for example images obtained using an acoustic microscope. The images of two targets are obtained, one image using acoustic waves and one image using optical waves, the edges of the images are determined and overlay between the two targets is obtained as the difference between the edges of the two images.