A system and methods for OCD metrology are provided including receiving multiple first sets of scatterometric data, dividing each set into k sub-vectors, and training, in a self-supervised manner, k2 auto-encoder neural networks that map each of the k sub-vectors to each other. Subsequently multiple respective sets of reference parameters and multiple corresponding second sets of scatterometric data are received and a transfer neural network (NN) is trained. Initial layers include a parallel arrangement of the k2 encoder neural networks. Target output of the transfer NN training is set to the multiple sets of reference parameters and feature input is set to the multiple corresponding second sets of scatterometric data, such that the transfer NN is trained to estimate new wafer pattern parameters from subsequently measured sets of scatterometric data.

A method for determining a process window of a patterning process based on a failure rate. The method includes obtaining a plurality of features printed on a substrate, grouping, based on a metric, the features into a plurality of groups, and generating, based on measurement data associated with a group of features, a base failure rate model for the group of features, wherein the base failure rate model identifies the process window related to the failure rate of the group of features. The method can further include generating, using the base failure rate model, a feature-specific failure rate model for a specific feature, wherein the feature-specific failure rate model identifies a feature-specific process window such that an estimated failure rate of the specific feature is below a specified threshold.

The present disclosure provides a measurement mark, a measurement layout, and a semiconductor structure measurement method. A measurement mark includes a first pattern, a second pattern, and a third pattern, the first pattern includes multiple first marks extending in a first direction and arranged in parallel at intervals in a second direction, the second pattern includes multiple second marks arranged at intervals in a staggered manner, and the third pattern includes multiple third marks arranged at intervals in a staggered manner; in projection of the measurement mark on the substrate, projection of the second mark separates projection of the first mark in the first direction; projection of the second pattern does not overlap with projection of the third pattern, and there is an offset distance between the projection of the third pattern and the projection of the second pattern in a third direction.

An assembly for collimating broadband radiation, the assembly including: a convex refractive singlet lens having a first spherical surface for coupling the broadband radiation into the lens and a second spherical surface for coupling the broadband radiation out of the lens, wherein the first and second spherical surfaces have a common center; and a mount for holding the convex refractive singlet lens at a plurality of contact points having a centroid coinciding with the common center.

Embodiments of the present disclosure relate to a metrology method and system for critical dimensions based on a dispersion relation in momentum space. The method comprises: establishing, in accordance with parameters of incident light and a modeled geometric topography of the target to be measured, a simulation dataset associated with a dispersion curve of the target to be measured in momentum space; training a neural-network-based prediction model based on the simulation dataset; obtaining, based on an actual measurement of the target to be measured by incident light, a dispersion relation pattern of the target to be measured in momentum space, wherein the dispersion relation pattern at least indicates a dispersion curve associated with the critical dimensions of the target to be measured; extracting, based on the dispersion relation pattern, features related to the dispersion curve from the dispersion relation pattern via the trained prediction model, to determine an estimated value associated with at least one critical dimension of the target to be measured. According to the method disclosed herein, at least one critical dimension is measured in a more efficient, economical and accurate way.

A metrology system includes a radiation source, first, second, and third optical systems, and a processor. The first optical system splits the radiation into first and second beams of radiation and impart one or more phase differences between the first and second beams. The second optical system directs the first and second beams toward a target structure to produce first and second scattered beams of radiation. The third optical system interferes the first and second scattered beams at an imaging detector. The imaging detector generates a detection signal based on the interfered first and second scattered beams. The metrology system modulates one or more phase differences of the first and second scattered beams based on the imparted one or more phase differences. The processor analyzes the detection signal to determine a property of the target structure based on at least the modulated one or more phase differences.

A pattern according to an embodiment includes first and second line patterns, each of the first and second line patterns extends in a direction intersecting a <111> direction and has a side surface, the side surface has at least one {111} crystal plane, the side surface of the first line pattern has a first roughness, and the side surface of the second line pattern has a second roughness larger than the first roughness.

The present disclosure provides a method for overlay error correction. The method includes: obtaining an overlay error based on a lower-layer pattern and an upper-layer pattern of a wafer, wherein the lower-layer pattern is obtained by first fabrication equipment through which the wafer passes, and the upper-layer pattern is obtained by exposure equipment; generating a corrected overlay error based on the overlay error and fabrication processes performed on the wafer after the first fabrication equipment and prior to the exposure equipment; and adjusting the exposure equipment based on the corrected overlay error.

A reflector comprising a hollow body having an interior surface defining a passage through the hollow body, the interior surface having at least one optical surface part configured to reflect radiation and a supporter surface part, wherein the optical surface part has a predetermined optical power and the supporter surface part does not have the predetermined optical power. The reflector is made by providing an axially symmetric mandrel; shaping a part of the circumferential surface of the mandrel to form at least one inverse optical surface part that is not rotationally symmetric about the axis of the mandrel; forming a reflector body around the mandrel; and releasing the reflector body from the mandrel whereby the reflector body has an optical surface defined by the inverse optical surface part and a supporter surface part defined by the rest of the outer surface of the mandrel.

An optical measurement apparatus includes a light source unit generating and outputting light, a polarized light generating unit generating polarized light from the light, an optical system generating a pupil image of a measurement target, using the polarized light, a self-interference generating unit generating multiple beams that are split from the pupil image, and a detecting unit detecting a self-interference image generated by interference of the multiple beams with each other.