Provided are methods of reducing the stress of a semiconductor wafer. A wafer map of a free-standing wafer is created using metrology tools. The wafer map is then converted into a power spectral density (PSD) using a spatial frequency scale. The fundamental component of bow is then compensated with a uniform film, e.g., silicon nitride (SiN), deposited on the back side of the wafer.

Described herein is a method for training a machine learning model to determine a source of error contribution to multiple features of a pattern printed on a substrate. The method includes obtaining training data having multiple datasets, wherein each dataset has error contribution values representative of an error contribution from one of multiple sources to the features, and wherein each dataset is associated with an actual classification that identifies a source of the error contribution of the corresponding dataset; and training, based on the training data, a machine learning model to predict a classification of a reference dataset of the datasets such that a cost function that determines a difference between the predicted classification and the actual classification of the reference dataset is reduced.

There is provided a system and method of a method of mask inspection, comprising: obtaining a first image representative of at least part of the mask; applying a printing threshold on the first image to obtain a second image; estimating a contour for each structural element of interest (SEI) of a group of SEIs, and extracting a set of attributes characterizing the contour, giving rise to a group of contours corresponding to the group of SEIs and respective sets of attributes associated therewith; for each given contour, identifying, among the remaining contours in the group of contours, one or more reference contours similar to the given contour, by comparing between the respective sets of attributes associated therewith; and measuring a deviation between the given contour and each reference contour thereof, giving rise to one or more measured deviations indicative of whether a defect is present.

An inspection apparatus for inspecting an object such as a pellicle for use in an EUV lithographic apparatus, the inspection apparatus including: a vacuum chamber; a load lock forming an interface between the vacuum chamber and an ambient environment; and a stage apparatus configured to receive the object from the load lock and displace the object inside the vacuum chamber, wherein the vacuum chamber includes a first parking position and a second parking position for temporarily storing the object.

Disclosed is an object table for holding an object, comprising: an electrostatic clamp arranged to clamp the object on the object table; a neutralizer arranged to neutralize a residual charge of the electrostatic clamp; a control unit arranged to control the neutralizer, wherein the residual charge is an electrostatic charge present on the electrostatic clamp when no voltage is applied to the electrostatic clamp.

A semiconductor device manufacturing system includes a photolithography apparatus that performs exposure. On a semiconductor substrate including a chip area and a scribe lane area. An etching apparatus etches the exposed semiconductor substrate. An observing apparatus images the etched semiconductor substrate. A controller controls the photolithography apparatus and the etching apparatus. The controller generates a first mask pattern and provides the first mask pattern to the photolithography apparatus. The photolithography apparatus performs exposure on the semiconductor substrate using the first mask pattern. The etching apparatus performs etching on the exposed semiconductor substrate to provide an etched semiconductor substrate. The observing apparatus generates a first semiconductor substrate image by imaging the etched semiconductor substrate corresponding to the scribe lane area. The controller generates a second mask pattern based on the first mask pattern and the first semiconductor substrate image, and provides the second mask pattern to the photolithography apparatus.

Disclosed herein is a method for increasing signal-to-noise (SNR) in optical imaging of defects on unpatterned wafers. The method includes: (i) irradiating a region of an unpatterned wafer with a substantially polarized, incident light beam, and (ii) employing relay optics to collect and guide, radiation scattered off the region, onto a segmented polarizer comprising at least four polarizer segments characterized by respective dimensions and polarization directions. The respective dimensions and polarization direction of each of the at least four polarizer segments are such that an overall power of background noise radiation, generated in the scattering of the incident light beam from the region and passed through all of the at least four polarizer segments, is decreased as compared to utilizing a linear polarizer.

Disclosed is a method of measuring a periodic structure on a substrate with illumination radiation having at least one wavelength, the periodic structure having at least one pitch. The method comprises configuring, based on a ratio of said pitch and said wavelength, one or more of: an illumination aperture profile comprising one or more illumination regions in Fourier space; an orientation of the periodic structure for a measurement; and a detection aperture profile comprising one or more separated detection regions in Fourier space. This configuration is such that: i) diffracted radiation of at least a pair of complementary diffraction orders is captured within the detection aperture profile, and ii) said diffracted radiation fills at least 80% of the one or more separated detection regions. The periodic structure is measured while applying the configured one or more of illumination aperture profile, detection aperture profile and orientation of the periodic structure.

A method of processing a wafer is provided. The method includes providing a reference plate below the wafer. The reference plate includes a reference pattern. The reference plate is imaged to capture an image of the reference pattern by directing light through the wafer. A first pattern is aligned using the image of the reference pattern. The first pattern is applied to a working surface of the wafer based on the aligning.

An inspection apparatus, including: an optical system configured to provide a beam of radiation to a surface to be measured and to receive redirected radiation from the surface; and a detection system configured to measure the redirected radiation, wherein the optical system includes an optical element to process the radiation, the optical element including a Mac Neille-type multilayer polarizing coating configured to produce a reduced chromatic offset of the radiation.