An apparatus and method are provided. The apparatus includes an imaging device; a stage movable relative to the imaging device; an isolation plate provided between the imaging device and the stage, including a horizontal glass plate; and a plurality of interferometers in electronic communication with a processor. The plurality of interferometers include three interferometers disposed on the imaging device, configured to direct a first beam set in a first direction toward the horizontal glass plate; and three interferometers disposed on the stage, configured to direct a second beam set in a second direction toward the horizontal glass plate, the second direction being opposite to the first direction. The processor is configured to measure distances between the imaging device and the isolation plate and distances between the stage and the isolation plate based on the first beam set and the second beam set reflected from the horizontal glass plate.

An overlay metrology system may include an illumination source and illumination optics to illuminate an overlay target on a sample with illumination from the illumination source as the sample is in motion with respect to the illumination from the illumination source in accordance with a measurement recipe. The overlay target may include one or more cells, where a single cell is suitable for measurement along a particular direction. Such a cell may include two or more gratings with different pitches. Further, the system may include two or more photodetectors, each configured to capture three diffraction lobes from the two or more grating structures. The system may further include a controller to determine an overlay measurement associated with each cell of the overlay target.

A method and a system for preparing a substrate with three dimensional features for immersion based inspection. The method may include (a) receiving, by a secondary chamber, an article that includes the substrate, a housing, and a transparent element; wherein the transparent element is sealingly coupled to the housing to provide a sealed inner space; wherein the sealed inner space may include a gap between a first surface of the substrate to a second surface of the transparent element; wherein the gap is filled with gas during the receiving of the article; (b) evacuating the gas from the gap while reducing a pressure within the secondary chamber and maintaining an integrity of the transparent element; (c) filling the gap with fluid while increasing the pressure within a secondary chamber inner space and maintaining an integrity of the transparent element; and (d) outputting the article from the secondary chamber.

A method for determining a likelihood that an assist feature of a mask pattern will print on a substrate. The method includes obtaining (i) a plurality of images of a pattern printed on a substrate and (ii) variance data the plurality of images of the pattern; determining, based on the variance data, a model configured to generate variance data associated with the mask pattern; and determining, based on model-generated variance data for a given mask pattern and a resist image or etch image associated with the given mask pattern, the likelihood that an assist feature of the given mask pattern will be printed on the substrate. The likelihood can be applied to adjust one or more parameters related to a patterning process or a patterning apparatus to reduce the likelihood that the assist feature will print on the substrate.

A system for measuring a beam. The system includes a measurement device configured to measure the beam and determine a signal based on the measured beam, and a fluid supply device configured to provide fluid as a fluid stream to, or surrounding, the beam. The system is configured to calculate noise of the signal, and to adjust a parameter of the fluid of the fluid stream to reduce the calculated noise.

A metrology system may include an optical metrology tool configured to produce an optical metrology output for one or more features on a processed substrate, and a metrology machine learning model that has been trained using a training set of (i) profiles, critical dimensions, and/or contours for a plurality of features, and (ii) optical metrology outputs for the plurality of features. The metrology machine learning model may be configured to: receive the optical metrology output from the optical metrology tool; and output the profile, critical dimension, and/or contour of the one or more features on the processed substrate.

Embodiments disclosed herein include a method of monitoring a photoresist deposition process. In an embodiment, the method comprises depositing a photoresist layer to a first thickness over a substrate, measuring a property of the photoresist layer with a first electromagnetic (EM) radiation source, depositing the photoresist layer to a second thickness over the substrate, and measuring the property of the photoresist layer with the first EM radiation source.

A metrology system may include an optical metrology tool configured to produce an optical metrology output for one or more features on a processed substrate, and a metrology machine learning model that has been trained using a training set of (i) profiles, critical dimensions, and/or contours for a plurality of features, and (ii) optical metrology outputs for the plurality of features. The metrology machine learning model may be configured to: receive the optical metrology output from the optical metrology tool; and output the profile, critical dimension, and/or contour of the one or more features on the processed substrate.

A metrology apparatus for measuring a parameter of interest of a target on a substrate, the metrology apparatus including: mn detectors, wherein m1 and n1; a first frame; and (n1) second frames; and (m1)n intermediate frames, wherein each detector is connected to one of the intermediate or first or second frames via a primary positioning assembly; and each intermediate frame is connected to one of the first or second frames via a secondary positioning assembly.

A laser beam metrology system (500) configured to co-operate with a laser beam system that is configured to sequentially direct a first laser beam pulse and a second laser beam pulse (430) to a target along two independent optical paths, the laser beam metrology system comprising a beam steering device (470) and a detection system (510). A laser beam system comprising the laser beam metrology system and a EUV source is also described.