Electron beam overlay targets and method of performing overlay measurements on a target using a semiconductor metrology tool are provided. One target includes a plurality of electron beam overlay elements and a plurality of two-dimensional elements that provide at least one two-dimensional imaging. The plurality of two dimensional elements are an array of evenly-spaced polygonal gratings across at least three rows and at least three columns. Another target includes a plurality of electron beam overlay elements and a plurality of AIMid elements. Each of the electron beam overlay elements includes at least two gratings that are overlaid at a perpendicular orientation to each other. The plurality of AIMid elements includes at least two gratings that are overlaid at a perpendicular orientation to each other.

An overlay metrology system may receive overlay data for in-die overlay targets within various fields on a skew training sample from one or more overlay metrology tools, wherein the in-die overlay targets within the fields have a range programmed overlay offsets, wherein the fields are fabricated with a range of programmed skew offsets. The system may further generate asymmetric target signals for the in-die overlay targets using an asymmetric function providing a value of zero when physical overlay is zero and a sign indicative of a direction of physical overlay. The system may further generate corrected overlay offsets for the in-die overlay targets on the asymmetric target signals, generate self-calibrated overlay offsets for the in-die overlay targets based on the programmed overlay offsets and the corrected overlay offsets, generate a trained overlay recipe, and generate overlay measurements for in-die overlay targets on additional samples using the trained overlay recipe.

An acoustic scatterometer has an acoustic source operable to project acoustic radiation onto a periodic structure and formed on a substrate. An acoustic detector is operable to detect the −1st acoustic diffraction order diffracted by the periodic structure and while discriminating from specular reflection (0th order). Another acoustic detector is operable to detect the +1st acoustic diffraction order diffracted by the periodic structure, again while discriminating from the specular reflection (0th order). The acoustic source and acoustic detector may be piezo transducers. The angle of incidence of the projected acoustic radiation and location of the detectors and are arranged with respect to the periodic structure and such that the detection of the −1st and +1st acoustic diffraction orders and discriminates from the 0th order specular reflection.

Metrology methods and targets are provided for reducing or eliminating a difference between a device pattern position and a target pattern position while maintaining target printability, process compatibility and optical contrast—in both imaging and scatterometry metrology. Pattern placement discrepancies may be reduced by using sub-resolved assist features in the mask design which have a same periodicity (fine pitch) as the periodic structure and/or by calibrating the measurement results using PPE (pattern placement error) correction factors derived by applying learning procedures to specific calibration terms, in measurements and/or simulations. Metrology targets are disclosed with multiple periodic structures at the same layer (in addition to regular target structures), e.g., in one or two layers, which are used to calibrate and remove PPE, especially when related to asymmetric effects such as scanner aberrations, off-axis illumination and other error sources.

An overlay correcting method capable of optimizing correction of an overlay within a scanner correction limit of a scanner of a scanner system, and a photolithography method, a semiconductor device manufacturing method and the scanner system which are based on the overlay correcting method are provided. The overlay correcting method includes collecting overlay data by measuring an overlay of a pattern; calculating correction parameters of the overlay by performing regularized regression using the overlay data, the regularized regression being based on a correction limit of the scanner such that the correction parameters fall within the correction limit of the scanner; and providing the correction parameters to the scanner.

A method of manufacturing a semiconductor device includes: forming a first outer box and a second outer box on a wafer, providing a photoresist layer on the wafer; and by removing a portion of the photoresist layer, forming a photoresist pattern including a first opening and a second opening that are horizontally apart from each other, wherein the first opening defines a first inner box superimposed on the first outer box in a plan view, the second opening defines a second inner box superimposed on the second outer box in the plan view, and a horizontal distance between the first opening and the second opening is about 150 μm to about 400 μm.

A method for monitoring performance of a manufacturing process is described. The method includes receiving one or more input signals that convey information related to geometry of a substrate generated by the manufacturing process; and determining, with a prediction model, variation in the manufacturing process based on the one or more input signals. A method for predicting substrate geometry associated with a manufacturing process is also described. The method includes receiving input information including geometry information and manufacturing process information for a substrate; and predicting, using a machine learning prediction model, output substrate geometry based on the input information. The method may further include tuning the predicted output substrate geometry. The tuning includes comparing the output substrate geometry to corresponding physical substrate measurements and/or predictions from a different non-machine learning prediction model, generating a loss function based on the comparison, and optimizing the loss function.

A measuring and calculating apparatus to measure and calculate a positional displacement amount of a pattern on a surface of a target object. The apparatus includes: a measuring unit to measure a first two-dimensional intensity distribution of a first diffracted light and a second two-dimensional intensity distribution of a second diffracted light; a storage unit to store a first and a second measurement data respectively indicating the first and the second two-dimensional intensity distribution; and an arithmetic unit to execute arithmetic processing using the first and the second measurement data to acquire difference data between the first and the second measurement data, and calculate a positional displacement amount of a difference pattern between the first and second patterns in accordance with the difference data.

Methods and systems for measurement of wafer tilt and overlay are described herein. In some embodiments, the measurements are based on the value of an asymmetry response metric and known wafer statistics. Spectral measurements are performed at two different azimuth angles, preferably separated by one hundred eighty degrees. A sub-range of wavelengths is selected with significant signal sensitivity to wafer tilt or overlay. An asymmetry response metric is determined based on a difference between the spectral signals measured at the two different azimuth angles within the selected sub-range of wavelengths. The value of the asymmetry response metric is mapped to an estimated value of wafer tilt or overlay. In some other embodiments, the measurement of wafer tilt or overlay is based on a trained measurement model. Training data may be programmed or determined based on one or more asymmetry response metrics at two different azimuth angles.

A recipe selection method includes obtaining measurements from metrology targets, metrology targets positioned on a semiconductor substrate, obtaining measurements from in-device targets, in-device targets positioned on the semiconductor substrate, and determining a recipe for accurate metrology using both metrology target measurements and in-device metrology measurements.