A method comprising determining aberrations caused by each lithographic apparatus of a set of lithographic apparatuses, calculating adjustments of the lithographic apparatuses which minimize differences between the aberrations caused by each of the lithographic apparatuses, and applying the adjustments to the lithographic apparatuses, providing better matching between the aberrations of patterns projected by the lithographic apparatuses.

A method including obtaining a selected component of optical aberration of or for a lithography apparatus, under a processing condition; computing an approximate of a cost function, based on the selected component; and producing an adjustment of the lithography apparatus or a patterning process that uses the lithography apparatus, based on the approximate of the cost function.

A method involving: obtaining a process model of a patterning process that includes or accounts for an average optical aberration of optical systems of a plurality of apparatuses for use with a patterning process; and applying the process model to determine an adjustment to a parameter of the patterning process to account for the average optical aberration.

Projection objective wave-front aberration detecting device and a detecting method thereof, wherein the projection objective wave-front aberration detecting device comprises a light source and illuminating system, an object plane grating, an object plane displacement stage, a measured projection objective, an image plane grating, a two-dimensional photoelectric sensor, an image plane displacement stage and a control processing unit. According to the invention, by controlling the length of the object plane grating line, or the periodic structure of the object plane grating perpendicular to the shearing diffraction direction, or the object plane grating to adopt a sinusoidal grating, or the image plane grating to adopt an amplitude-phase hybrid grating, the complexity of an interference field is reduced, and the wave-front aberration detection speed and precision are improved, and the precision and speed of in-situ wave-front aberration detection can be improved.

A method of adjusting a metrology apparatus, the method including: spatially dividing an intensity distribution of a pupil plane of the metrology apparatus into a plurality of pixels; and reducing an effect of a structural asymmetry in a target on a measurement by the metrology apparatus on the target, by adjusting intensities of the plurality of pixels.

A lithographic apparatus comprises a projection system comprising position sensors to measure a position of optical elements of the projection system. The positions sensors are referenced to a sensor frame. Damping actuators damp vibrations of the sensor frame. A control device drives the actuators and is configured to derive sensor frame damping force signals from at least one of the acceleration signals and the sensor frame position signals, derive an estimated line of sight error from the position signals, determine actuator drive signals from the sensor frame damping force signals and the estimated line of sight error, drive the actuators using the actuator drive signals to dampen the sensor frame and to at least partly compensate the estimated line of sight error.

A method for quantifying the effect of pupil function variations on a lithographic effect within a lithographic apparatus is disclosed. The method comprises: determining a discrete, two-dimensional sensitivity map in a pupil plane of the lithographic apparatus, wherein the lithographic effect is given by the inner product of said sensitivity map with a discrete, two-dimensional pupil function variation map of a radiation beam in the pupil plane. The pupil plane of a lithographic apparatus generally refers to the exit pupil of a projection system of the lithographic apparatus. Pupil function variations may comprise: relative phase variations within the pupil plane and/or relative intensity variations within the pupil plane.

An appliance for moiré measurement of an object (12) includes a grating arrangement having a first grating (11) positioned upstream of the object and including test structures to be imaged, a second grating (14) positioned downstream of the object, and an evaluation unit having at least one detector evaluating moiré structures produced by superposing the two gratings in a detection plane situated downstream of the second grating. The object is an anamorphic imaging system, and the respective grating periods of the first grating and of the second grating are selected so that the grating period of the second grating corresponds to a common multiple or a common divisor of the respective periods of two test structure images of the test structures of the first grating produced by the imaging system in two different measurement positions. The two measurement positions differ in relative grating arrangement position and test object position.

Disclosed is a method of, and associated metrology apparatus for, determining a characteristic of a target on a substrate. The method comprises obtaining a plurality of intensity asymmetry measurements, each intensity asymmetry measurement relating to a target formed on the substrate and determining a sensitivity coefficient corresponding to each target, from the plurality of intensity asymmetry measurements. Using these sensitivity coefficients a representative sensitivity coefficient is determined for said plurality of targets or a subset greater than one thereof. The characteristic of the target can then be determined using the representative sensitivity coefficient.

A refractive projection lens for imaging a pattern in an object plane of the projection lens into an image plane of the projection lens via electromagnetic radiation of a mercury vapor lamp includes a multiplicity of lens elements are arranged along an optical axis between the object and image planes. The lens elements image a pattern in the object plane into the image plane with a reducing imaging scale. The lens elements include first lens elements made of a first material with a relatively low Abbe number and a second lens elements made of a second material with a higher Abbe number relative to the first material.