Abstract: Methods and systems disclosed herein can measure thin film stacks, such as film on grating and bandgap on grating in semiconductors. For example, the thin film stack may be a 1D film stack, a 2D film on grating, or a 3D film on grating. One or more effective medium dispersion models are created for the film stack. Each effective medium dispersion model can substitute for one or more layers. A thickness of one or more layers can be determined using the effective medium dispersion based scatterometry model. In an instance, three effective medium dispersion based scatterometry models are developed and used to determine thickness of three layers in a film stack.

Abstract: Methods and systems for focusing and measuring by mean of an interferometer device, having an optical coherence tomography (OCT) focusing system, by separately directing an overlapped measurement and reference wavefront towards a focus sensor and towards an imaging sensor; where a predefined focusing illumination spectrum of the overlapped wavefront is directed towards the focus sensor, and where a predefined measurement illumination spectrum of the overlapped wavefront is directed towards the imaging sensor. Methods and systems for maintaining focus of an interferometer device, having an OCT focusing system, during sample's stage moves.

Abstract: Imaging objectives and inspection systems equipped with such imaging objectives are disclosed. The imaging objective may include a front objective configured to produce a diffraction limited intermediate image. The imaging objective may also include a relay configured to receive the intermediate image produced by the front objective. The relay may include three spherical mirrors positioned to deliver a projection of the intermediate image to a fixed image plane.

Abstract: Systems and methods for defection classification in a semiconductor process are provided. The system includes a communication line configured to receive a defect image of a wafer from the semiconductor process and a deep-architecture neural network in electronic communication with the communication line. The neural network has a first convolution layer of neurons configured to convolve pixels from the defect image with a filter to generate a first feature map. The neural network also includes a first subsampling layer configured to reduce the size and variation of the first feature map. A classifier is provided for determining a defect classification based on the feature map. The system may include more than one convolution layers and/or subsampling layers. A method includes extracting one or more features from a defect image using a deep-architecture neural network, for example a convolutional neural network.

Abstract: A library expansion system, method, and computer program product for metrology are provided. In use, processing within a first multi-dimensional library is performed by a metrology system. During the processing within the first multi-dimensional library, a second multi-dimensional library is identified. The processing is then transitioned to the second multi-dimensional library. Further, processing within the second multi-dimensional library is performed by the metrology system.

Abstract: Defects from a hot scan can be saved, such as on persistent storage, random access memory, or a split database. The persistent storage can be patch-based virtual inspector virtual analyzer (VIVA) or local storage. Repeater defect detection jobs can determined and the wafer can be inspected based on the repeater defect detection jobs. Repeater defects can be analyzed and corresponding defect records to the repeater defects can be read from the persistent storage. These results may be returned to the high level defect detection controller.

Abstract: Methods and systems are presented to reduce the illumination spot size projected onto a measurement target and associated spillover onto area surrounding a measurement target. In one aspect, a spatial light modulator (SLM) is located in the illumination path between the illumination light source and the measurement sample. The SLM is configured to modulate amplitude, phase, or both, across the path of the illumination light to reduce wavefront errors. In some embodiments, the desired state of the SLM is based on wavefront measurements performed in an optical path of the metrology system. In another aspect, an illumination aperture having an image plane tilted at an oblique angle with respect to a beam of illumination light is employed to overcome defocusing effects in metrology systems that employ oblique illumination of the measurement sample. In some embodiments, the illumination aperture, objective lens, and specimen are aligned to satisfy the Scheimpflug condition.

Abstract: A scanning electron microscopy system with improved image beam stability is disclosed. The system includes an electron beam source configured to generate an electron beam and a set of electron-optical elements to direct at least a portion of the electron beam onto a portion of the sample. The system includes an emittance analyzer assembly. The system includes a splitter element configured to direct at least a portion secondary electrons and/or backscattered electrons emitted by a surface of the sample to the emittance analyzer assembly. The emittance analyzer assembly is configured to image at least one of the secondary electrons and/or the backscattered electrons.

Abstract: For three-dimensional topography measurement of a surface of an object patterned illumination is projected on the surface through an objective. A relative movement between the object and the objective is carried out, and plural images of the surface are recorded through the objective by a detector. The direction of the relative movement includes an oblique angle with an optical axis of the objective. Height information for a given position on the surface is derived from a variation of the intensity recorded from the respective position. Also, patterned illumination and uniform illumination may be projected alternatingly on the surface, while images of the surface are recorded during a relative movement of the object and the objective along an optical axis of the objective. Uniform illumination is used for obtaining height information for specular structures on the surface, patterned illumination is used for obtaining height information on other parts of the surface.

Abstract: Disclosed are methods and apparatus for inspecting an extreme ultraviolet (EUV) reticle using an optical inspection tool. An inspection tool having a pupil filter positioned at an imaging pupil is used to obtain a test image or signal from an output beam that is reflected and scattered from a test portion of an EUV test reticle. The pupil filter is configured to provide phase contrast in the output beam. A reference image or signal is obtained for a reference reticle portion that is designed to be identical to the test reticle portion. The test and reference images or signals are compared and it is determined whether the test reticle portion has any candidate defects based on such comparison. For each of a plurality of test reticle portions of the reticle, the operations for using the inspection tool, obtaining a reference image or signal, comparing, and determining are repeated. A defect report is generated based on any candidate defects that have been determined to be present.

Abstract: Methods and systems are disclosed for determining overlay in a semiconductor manufacturing process. Radiation reflected from a diffraction pattern in a metrology target may include +1 and ?1 diffraction patterns at different wavelengths and focal positions. The different wavelengths of radiation may be in a waveband where the sensitivity of contrast to wavelength is at a maximum. The reflected radiation may be analysed to obtain measured values of overlay as well as amplitude and/or phase corresponding to points distributed over the target, for different wavelengths and focal positions. The measured values of overlay may undergo a series of operations to determine the overlay. The determination may use an assumption that the amplitude and phase are unequal in the +1 and ?1 diffraction orders.

Abstract: A system for illuminating a sample with a spectrally filtered illumination source includes an illumination source configured to generate a beam of illumination having a first set of wavelengths. In addition, the system includes a wavelength filtering sub-system, a sample stage, an illumination sub-system, a detector, and an objective to focus illumination from the surface of one or more samples and focus the collected illumination to the detector. Further, the wavelength filtering sub-system includes one or more first dispersive elements positioned to introduce spatial dispersion into the beam, a spatial filter element, and one or more dispersive elements positioned to remove spatial dispersion from the beam. The spatial filter element is further positioned to pass at least a portion of the beam including a second set of wavelengths, wherein the second set of wavelengths is a subset of the first set of wavelengths.

Abstract: Methods and systems for evaluating the performance of multiple patterning processes are presented. Patterned structures are measured and one or more parameter values characterizing geometric errors induced by the multiple patterning process are determined. In some examples, a single patterned target and a multiple patterned target are measured, the collected data fit to a combined measurement model, and the value of a structural parameter indicative of a geometric error induced by the multiple patterning process is determined based on the fit. In some other examples, light having a diffraction order different from zero is collected and analyzed to determine the value of a structural parameter that is indicative of a geometric error induced by a multiple patterning process. In some embodiments, a single diffraction order different from zero is collected. In some examples, a metrology target is designed to enhance light diffracted at an order different from zero.

Abstract: Disclosed are methods and apparatus for facilitating defect detection in a multilayer stack. The method includes selection of a set of structure parameters for modeling a particular multilayer stack and a particular defect contained within such particular multilayer stack and a set of operating parameters for an optical inspection system. Based on the set of structure and operating parameters, an electromagnetic simulation is performed of waves scattered from the particular multilayer stack and defect and arriving at a collection pupil of the optical inspection system.

Abstract: Methods and systems for matching measurement spectra across one or more optical metrology systems are presented. The values of one or more system parameters used to determine the spectral response of a specimen to a measurement performed by a target metrology system are optimized. The system parameter values are optimized such that differences between measurement spectra generated by a reference system and the target system are minimized for measurements of the same metrology targets. Methods and systems for matching spectral errors across one or more optical metrology systems are also presented. A trusted metrology system measures the value of at least one specimen parameter to minimize model errors introduced by differing measurement conditions present at the time of measurement by the reference and target metrology systems. Methods and systems for parameter optimization based on low-order response surfaces are presented to reduce the compute time required to refine system calibration parameters.

Abstract: Electron source designs are disclosed. The emitter structure, which may be silicon, has a layer on it. The layer may be graphene or a photoemissive material, such as an alkali halide. An additional layer between the emitter structure and the layer or a protective layer on the layer can be included. Methods of operation and methods of manufacturing also are disclosed.

Abstract: Methods and systems are disclosed that provide nuisance reduction in images, such as semiconductor images that include one or more metal lines. A potential defect is correlated against pixel grey level intensity charts for two perpendicular axes. A position of the potential defect relative to a pattern, such as a metal line, is determined along the two axes. The potential defect can be classified as a defect of interest or nuisance event.

Abstract: Metal film thickness can be determined using the sheet resistance, resistivity, and temperature coefficient of resistivity for the metal film. Variation in film thickness measurements caused by resistivity can be reduced or eliminated. A probe head may be used for some of the measurements of the metal film. The probe head can include a temperature sensor used during sheet resistance measurements. A wafer on a chuck is heated, such as using the chuck or the probe head, for the measurements.

Abstract: Information from metrology tools can be used during inspection or review with a scanning electron microscope. Metrology measurements of a wafer are interpolated and/or extrapolated over a field, which creates modified metrology data. The modified metrology data is associated with defect attributes from inspection measurements of a wafer. A wafer review sampling plan is generated based on the defect attributes and the modified metrology data. The wafer review sampling plan can be used during review of a wafer using the scanning electron microscope.

Abstract: The disclosure is directed to providing visual feedback for inspection algorithms and difference filters used to process test and reference images from an inspection system. A user interface may be configured for displaying information and accepting user commands. A computing system communicatively coupled to the user interface may be configured to receive at least one set of test and reference images collected by the inspection system. The computing system may be further configured to provide at least one visual representation of the test and reference images via the user interface to show effects of an inspection algorithm and/or difference filter.