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.

An imprint apparatus for forming a pattern of an imprint material on a substrate using a mold having a mesa including a pattern region where a pattern and a mark are formed. The apparatus includes an alignment optical system which includes an illumination system configured to illuminate the mark with illumination light and a detecting system configured to detect an image of the mark illuminated by the illumination system. The illumination system includes a limiter configured to limit incidence of the illumination light to a side of the mesa, a ridge line of the mesa, and an outer region of the side.

A patterning device pre-alignment sensor system is disclosed. The system comprises at least one illumination source configured to provide an incident beam along a normal direction towards a patterning device. The system further comprises an object lens group channel along the normal direction configured to receive a 0th order refracted beam from the patterning device. The system further comprises a first light reflector configured to redirect the 0th order refracted beam to form a first retroreflected beam. The system further comprises a first image lens group channel configured to transmit the first retroreflected beam to a first light sensor. The first light sensor is configured to detect the first retroreflected beam to determine a location feature of the patterning device.

A method including: determining recipe consistencies between one substrate measurement recipe of a plurality of substrate measurement recipes and each other substrate measurement recipe of the plurality of substrate measurement recipes; calculating a function of the recipe consistencies; eliminating the one substrate measurement recipe from the plurality of substrate measurement recipes if the function meets a criterion; and reiterating the determining, calculating and eliminating until a termination condition is met. Also disclosed herein is a substrate measurement apparatus, including a storage configured to store a plurality of substrate measurement recipes, and a processor configured to select one or more substrate measurement recipes from the plurality of substrate measurement recipes based on recipe consistencies among the plurality of substrate measurement recipes.

The present invention provides a measurement apparatus that measures a position of an object which includes a first mark and a second mark, comprising: an image capturing unit configured to capture the first mark and the second mark in a state in which the first mark and the second mark are contained in a field of view; and a polarizing element configured to generate different polarization directions from each other in light from the first mark and in light from the second mark which are incident on the image capturing unit.

An alignment apparatus includes an illumination system configured to direct one or more illumination beams towards an alignment target and receive the diffracted beams from the alignment target. The alignment apparatus also includes a self-referencing Interferometer configured to generate two diffraction sub-beams, wherein the two diffraction sub-beams are orthogonally polarized, rotated 180 degrees with respect to each other around an alignment axis, and spatially overlapped. The alignment apparatus further includes a beam analyzer configured to generate interference between the overlapped components of the diffraction sub-beams and produce two orthogonally polarized optical branches, and a detection system configured to determine a position of the alignment target based on light intensity measurement of the optical branches, wherein the measured light intensity is temporally modulated by a phase modulator.

A method of applying a measurement correction includes determining an orthogonal subspace used to characterize a first principal component of the measurement and a second principal component of the measurement, and rotating the orthogonal subspace by a first angle such that the first principle component rotates to become a first factor vector and the second principle component rotates to become a second factor vector. An asymmetry vector is generated by rotating the second factor vector by a second angle, where the asymmetry vector and the first factor vector define a non-orthogonal subspace. An asymmetry contribution is determined in the measurement based on the projection of the measurement onto the first factor vector in the non-orthogonal subspace. The method also includes subtracting the asymmetry contribution from the measurement.

According to one embodiment, a measurement method includes generating mark position information, determining at least one of a first arrangement pattern or a second arrangement pattern, and calculating displacement between a first member and a second member. The mark position information is generated after the second member is formed on the first member, and indicates a relative positional relationship between a first alignment mark formed on the first member and including bright portions and dark portions, and a second alignment mark formed on the second member and including the bright portions and the dark portions. The first arrangement pattern indicates an arrangement pattern of bright portions and dark portions of the first alignment mark. The second arrangement pattern indicates an arrangement pattern of the bright portions and the dark portions of the second alignment mark. The first arrangement pattern is determined on the basis of captured data of a reference mark formed in a region different from the region where the first alignment mark is formed and the region where the second alignment mark is formed. The displacement is calculated on the basis of the mark position information and at least one of the first arrangement pattern or the second arrangement pattern.

An illumination apparatus configured to provide illumination while changing a spectrum of light from a light source includes a wavelength variable unit configured to change a spectrum of irradiating light, and an optical system configured to irradiate the wavelength variable unit with the light from the light source. The wavelength variable unit is disposed so that an incident surface of the wavelength variable unit on which the light emitted from the optical system is incident is tilted with respect to a plane perpendicular to an optical axis of the optical system.

An apparatus for and method of sensing multiple alignment marks in which the optical axis of a detector is divided into multiple axes each of which can essentially simultaneously detect a separate alignment mark to generate a signal which can then be multiplexed and presented to a single detector or multiple detectors thus permitting more rapid detection of multiple marks.