Systems and methods for tuning photolithographic processes are described. A model of a target scanner is maintained defining sensitivity of the target scanner with reference to a set of tunable parameters. A differential model represents deviations of the target scanner from the reference. The target scanner may be tuned based on the settings of the reference scanner and the differential model. Performance of a family of related scanners may be characterized relative to the performance of a reference scanner. Differential models may include information such as parametric offsets and other differences that may be used to simulate the difference in imaging behavior.

For determining a focus position of a lithography mask (e.g., 5), a focus stack of a measurement region free of structures to be imaged is recorded and the speckle patterns of the recorded images are evaluated.

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 for mitigating an effect of non-uniform pellicle degradation on control of a substrate patterning process and an associated lithographic apparatus. The method includes quantifying an effect of the non-uniform pellicle degradation on one or more properties of patterned features, such as one or more metrology targets, formed on the substrate by the substrate patterning process. A process control correction is then determined based on the quantification of the effect of the non-uniform pellicle degradation.

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.

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.

Apparatuses and methods for metrology on devices using fast marching level sets are disclosed herein. An example method at least includes initiating a fast marching level set seed on an image, propagating a fast marching level set curve from the fast marching level set seed to locate boundaries of a plurality of regions of interest within the image, and performing metrology on the regions of interest based in part on the boundaries.

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 facet mirror for EUV projection lithography has a plurality of facets for reflecting EUV illumination light. At least some of the facets are in the form of alignment facets and have a reflection surface, the edge contour of which is aligned along two alignment coordinates of an overall facet arrangement. The reflection surface of at least one of the alignment facets has a surface shape that exhibits different curvatures along two axes of curvature. The axes of curvature are tilted about a finite axis tilt angle relative to the alignment coordinates of the overall facet arrangement. The result is a facet mirror with increased EUV throughput, particularly for prolonged operation of a projection exposure apparatus that is equipped therewith.

An object is to provide an illumination apparatus that achieves illumination with a uniform illuminance distribution, while reducing a light quantity loss. An illumination apparatus for illuminating an illumination target surface has: a deflection member configured to form an illuminance distribution with a periodic pattern along a predetermined direction on a predetermined face traversing an optical path; and an optical integrator system having a plurality of wavefront division facets arrayed on the predetermined face and configured to form secondary light sources with use of a beam from the deflection member; the deflection member forms the illuminance distribution with the periodic pattern of an integer times or a unit fraction times an array period of the plurality of wavefront division facets.