A mirror array, at least some of the mirrors of the array comprising a reflective surface and an arm which extends from a surface opposite to the reflective surface, wherein the mirror array further comprises a support structure provided with a plurality of sensing apparatuses, the sensing apparatuses being configured to measure gaps between the sensing apparatuses and the arms which extend from the mirrors.

Correction information is acquired for compensating for a measurement error of a second encoder system that occurs due to a displacement between four sections of a scale member of the second encoder system, based on measurement information of the second encoder system obtained in a fifth area in which four heads of the second encoder system that are provided on a second stage, which holds a substrate, respectively face the four sections of the scale member.

An evaluation method for evaluating an aberration of a projection optical system in an exposure apparatus is provided. A first prediction coefficient of a first prediction formula for an aberration that is symmetrical with respect to an optical axis of the projection optical system is obtained, and a second prediction coefficient of a second prediction formula for an aberration that is asymmetrical with respect to the optical axis of the projection optical system is obtained. The aberration of the projection optical system is evaluated using the first prediction coefficient in a case where the shape of the illuminated region is determined as symmetrical with respect to the optical axis, and the aberration of the projection optical system is evaluated using the first and the second prediction coefficients in a case where the shape of the illuminated region is asymmetrical with respect to the optical axis.

A method including: obtaining a measurement of a metrology target on a substrate processed using a patterning process, the measurement having been obtained using measurement radiation; and deriving a parameter of interest of the patterning process from the measurement, wherein the parameter of interest is corrected by a stack difference parameter, the stack difference parameter representing an un-designed difference in physical configuration between adjacent periodic structures of the target or between the metrology target and another adjacent target on the substrate.

Within area where of four heads installed on a wafer stage, heads included in the first head group and the second head group to which three heads each belong that include one head different from each other face the corresponding areas on a scale plate, the wafer stage is driven based on positional information which is obtained using the first head group, as well as obtain the displacement (displacement of position, rotation, and scaling) between the first and second reference coordinate systems corresponding to the first and second head groups using the positional information obtained using the first and second head groups. By using the results and correcting measurement results obtained using the second head group, the displacement between the first and second reference coordinate systems is calibrated, which allows the measurement errors that come with the displacement between areas on scale plates where each of the four heads face.

Within area where of four heads installed on a wafer stage, heads included in the first head group and the second head group to which three heads each belong that include one head different from each other face the corresponding areas on a scale plate, the wafer stage is driven based on positional information which is obtained using the first head group, as well as obtain the displacement (displacement of position, rotation, and scaling) between the first and second reference coordinate systems corresponding to the first and second head groups using the positional information obtained using the first and second head groups. By using the results and correcting measurement results obtained using the second head group, the displacement between the first and second reference coordinate systems is calibrated, which allows the measurement errors that come with the displacement between areas on scale plates where each of the four heads face.

An illuminance distribution response amount as the change amount of the illuminance distribution pattern, associating the position in the irradiation region in the lengthwise direction with the change amount of the illuminance with respect to the change in the drive current, has previously been acquired and stored in a storage unit for each light-emitting block. There is provided an arithmetic processing unit that determines (estimates) a current command value of each of the light-emitting blocks based on a present current command value of each of the light-emitting blocks and the change amount of the illuminance distribution pattern of each light-emitting block in order to bring a present illuminance distribution pattern in the irradiation region in a lengthwise direction close to a target illuminance distribution pattern.

A measurement apparatus (10) for measuring a wavefront aberration of an imaging optical system (12) includes (i) a measurement wave generating module (24) which generates a measurement wave (26) radiated onto the optical system and which includes an illumination system (30) illuminating a mask plane (14) with an illumination radiation (32), as well as coherence structures (36) arranged in the mask plane, and (ii) a wavefront measurement module (28) which measures the measurement wave after passing through the optical system and determines from the measurement result, with an evaluation device (46), a deviation of the wavefront of the measurement wave from a desired wavefront. The evaluation device (46) determines an influence of an intensity distribution (70) of the illumination radiation in the region of the mask plane on the measurement result and, when determining the deviation of the wavefront, utilizes the influence of the intensity distribution.

A method for setting an illumination setting for illuminating an object field of a projection exposure apparatus includes taking into account the sensitivity of a performance variable for changes in the intensity of the illumination radiation in the illumination pupil.

The present disclosure provides an extreme ultraviolet (EUV) lithography system including a radiation source and an EUV control system integrated with the radiation source. The EUV control system includes a 3-dimensional diagnostic module (3DDM) designed to collect a laser beam profile of a laser beam from the radiation source in a 3-dimensional (3D) mode, an analysis module designed to analyze the laser beam profile, a database designed to store the laser beam profile, and an EUV control module designed to adjust the radiation source. The analysis module is coupled with the database and the EUV control module. The database is coupled with the 3DDM and the analysis module. The EUV control module is coupled with the analysis module and the radiation source.