Abstract: Methods and systems for generating unbiased wafer defect samples are provided. One method includes selecting the defects detected by each of multiple scans performed on a wafer that have the most diversity in one or more defect attributes such that a diverse set of defects are selected across each scan. In addition, the method may include selecting the defects such that any defect that is selected and is common to two or more of the scans is not selected twice and any defects that are selected are diverse with respect to the common, selected defect. Furthermore, no sampling, binning, or classifying of the defects may be performed prior to selection of the defects such that the sampled defects are unbiased by any sampling, binning, or classifying method.

Abstract: The present disclosure is directed to a method for inspecting a wafer, the wafer including a film deposited on a surface of the wafer. The film may have a thickness that varies over the surface of the wafer. The method includes the step of measuring the thickness, refractive index, and extinction coefficient of the film across the surface of the wafer. With this data a film curve is created in real time. The method also includes the step of determining a size of a defect on the surface based on at least the film curve.

Abstract: The disclosure is directed to a system and method of managing illumination energy applied to illuminated portions of a scanned wafer to mitigate illumination-induced damage without unnecessarily compromising SNR of an inspection system. The wafer may be rotated at a selected spin frequency for scanning wafer defects utilizing the inspection system. Illumination energy may be varied over at least one scanned region of the wafer as a function of radial distance of an illuminated portion from the center of the wafer and the selected spin frequency of the wafer. Illumination energy may be further applied constantly over one or more scanned regions of the wafer beyond a selected distance from the center of the wafer.

Abstract: Systems and methods for improving results of wafer higher order shape (HOS) characterization and wafer classification are disclosed. The systems and methods in accordance with the present disclosure are based on localized shapes. A wafer map is partitioned into a plurality of measurement sites to improve the completeness of wafer shape representation. Various site based HOS metric values may be calculated for wafer characterization and/or classification purposes, and may also be utilized as control input for a downstream application. In addition, polar grid partitioning schemes are provided. Such polar grid partitioning schemes may be utilized to partition a wafer surface into measurement sites having uniform site areas while providing good wafer edge region coverage.

Abstract: Systems and methods for prediction of in-plane distortions (IPD) due to wafer shape in semiconductor wafer chucking process is disclosed. A process to emulate the non-linear finite element (FE) contact mechanics model based IPD prediction is utilized in accordance with one embodiment of the present disclosure. The emulated FE model based prediction process is substantially more efficient and provides accuracy comparable to the FE model based IPD prediction that utilizes full-scale 3-D wafer and chuck geometry information and requires computation intensive simulations. Furthermore, an enhanced HOS IPD/OPD prediction process based on a series of Zernike basis wafer shape images is also disclosed.

Abstract: Methods and systems for detecting defects on a wafer using defect-specific information are provided. One method includes acquiring information for a target on a wafer. The target includes a pattern of interest formed on the wafer and a known DOI occurring proximate to or in the pattern of interest. The information includes an image of the target on the wafer. The method also includes searching for target candidates on the wafer or another wafer. The target candidates include the pattern of interest. The target and target candidate locations are provided to defect detection. In addition, the method includes detecting the known DOI in the target candidates by identifying potential DOI locations in images of the target candidates and applying one or more detection parameters to images of the potential DOI locations.

Abstract: The disclosure is directed to a system and method for determining at least one characteristic of an illumination beam emanating from an illumination source. A substrate having a plurality of apertures may be actuated through an illumination beam so that apertures at different spatial offsets are scanned through the illumination beam at one or more levels of focus. Portions of illumination directed through scanned apertures may be received by at least one detector. At least one characteristic of the illumination beam may be extracted from data points associated with intensity levels associated with detected portions of illumination. Furthermore, multiple determinations of a beam characteristic made over a period of time may be utilized to calibrate the illumination source.

Abstract: Methods, systems, and structures for monitoring incident beam position in a wafer inspection system are provided. One structure includes a feature formed in a chuck configured to support a wafer during inspection by the wafer inspection system. The chuck rotates the wafer in a theta direction and simultaneously translates the wafer in a radial direction during the inspection. An axis through the center of the feature is aligned with a radius of the chuck such that a position of the axis relative to an incident beam of the wafer inspection system indicates changes in the incident beam position in the theta direction.

Abstract: Methods for inspecting a wafer and/or predicting one or more characteristics of a device being formed on a wafer are provided. One method includes acquiring images for multiple die printed on a wafer, each of which is printed by performing a double patterning lithography process on the wafer and which include two or more die printed at nominal values of overlay for the double patterning lithography process and one or more die printed at modulated values of the overlay; comparing the images acquired for the multiple die printed at the nominal values to the images acquired for the multiple die printed at the modulated values; and detecting defects in the multiple die printed at the modulated values based on results of the comparing step.

Abstract: An inspection system with selectable apodization includes an illumination source configured to illuminate a surface of a sample, a detector configured to detect at least a portion of light emanating from the surface of the sample, the illumination source and the detector being optically coupled via an optical pathway of an optical system, a selectably configurable apodization device disposed along the optical pathway, wherein the apodization device includes one or more apodization elements operatively coupled to one or more actuation stages configured to selectably actuate the one or more apodization elements along one or more directions, and a control system communicatively coupled to the one or more actuation and configured to selectably control apodization of illumination transmitted along the optical pathway by controlling an actuation state of the one or more apodization elements.

Abstract: Methods and systems for enhancing metrology sensitivity to particular parameters of interest are presented. Field enhancement elements (FEEs) are constructed as part of a specimen to enhance the measurement sensitivity of structures of interest present on the specimen. The design of the FEEs takes into account measurement goals and manufacturing design rules to make target fabrication compatible with the overall device fabrication process. Measurement of opaque materials, high-aspect ratio structures, structures with low-sensitivity, or mutually correlated parameters is enhanced by the addition of FEEs. Exemplary measurements include critical dimension, film thickness, film composition, and optical scatterometry overlay. In some examples, a target element includes different FEEs to improve the measurement of different structures of interest. In other examples, different target elements include different FEEs.

Abstract: Determination of one or more optical characteristics of a structure of a semiconductor wafer includes measuring one or more optical signals from one or more structures of a sample, determining a background optical field associated with a reference structure having a selected set of nominal characteristics based on the one or more structures, determining a correction optical field suitable for at least partially correcting the background field, wherein a difference between the measured one or more optical signals and a signal associated with a sum of the correction optical field and the background optical field is below a selected tolerance level, and extracting one or more characteristics associated with the one or more structures utilizing the correction optical field.

Abstract: An optical reticle inspection tool is used during a first inspection to obtain, for each set of one or more patch areas of the reticle, a reference average of multiple reference intensity values corresponding to light measured from sub-areas of each patch area. After using the reticle in photolithography processes, the optical reticle inspection tool is used during a second inspection to obtain, for each set of one or more patch areas, an average of multiple test intensity values corresponding to light measured from the of sub-areas. The first and second inspections use the same tool setup recipe. A difference intensity map is generated, and such map comprises map values that each corresponds to a difference between each average of the test and reference intensity values for each set of one or more patches. The difference intensity map indicates whether the reticle has degraded over time more than a predefined level.

Abstract: One embodiment relates to a pattern data system for maskless electron beam lithography. The system includes a renderer that receives pre-exposure die image data, performs rendering of the pre-exposure die image data to generate raster data. The system further includes a plurality of data distributors communicatively coupled to the renderer. Each data distributor adapts the raster data to characteristics of an associated pattern writer. Other embodiments, aspects and feature are also disclosed.

Abstract: Methods and systems for segmenting pixels for wafer inspection are provided. One method includes determining a statistic for individual pixels based on a characteristic of the individual pixels in an image acquired for a wafer by an inspection system. The method also includes assigning the individual pixels to first segments based on the statistic. In addition, the method includes detecting one or more edges between the first segments in an image of the first segments and generating an edge map by projecting the one or more edges across an area corresponding to the image for the wafer. The method further includes assigning the individual pixels to second segments by applying the first segments and the edge map to the image for the wafer thereby segmenting the image. Defect detection is performed based on the second segments to which the individual pixels are assigned.

Abstract: Methods and systems for reducing wafer shape and thickness measurement errors resulted from cavity shape changes are disclosed. Cavity calibration process is performed immediately before the wafer measurement. Calibrating the cavity characteristics every time the method is executed reduces wafer shape and thickness measurement errors resulted from cavity shape changes. Additionally or alternatively, a polynomial fitting process utilizing a polynomial of at least a second order is utilized for cavity tilt estimation. High order cavity shape information generated using high order polynomials takes into consideration cavity shape changes due to temperature variations, stress or the like, effectively increases accuracy of the wafer shape and thickness information computed.

Abstract: A plasma cell for use in a laser-sustained plasma light source includes a plasma bulb configured to contain a gas suitable for generating a plasma, the plasma bulb being substantially transparent to light emanating from a pump laser configured to sustain the plasma within the plasma bulb, wherein the plasma bulb is substantially transparent to at least a portion of a collectable spectral region of illumination emitted by the plasma, and a filter layer disposed on an interior surface of the plasma bulb, the filter layer configured to block a selected spectral region of the illumination emitted by the plasma.

Abstract: Methods and systems for generating a wafer inspection process are provided. One method includes storing output of detector(s) of an inspection system during scanning of a wafer regardless of whether the output corresponds to defects detected on the wafer and separating physical locations on the wafer that correspond to bit failures detected by testing of the wafer into a first portion of the physical locations at which the defects were not detected and a second portion of the physical locations at which the defects were detected. In addition, the method includes applying defect detection method(s) to the stored output corresponding to the first portion of the physical locations to detect defects at the first portion of the physical locations and generating a wafer inspection process based on the defects detected by the defect detection method(s) at the first portion of the physical locations.

Abstract: Systems and methods are presented to enhance and isolate residual signals indicative of the speckle field based on measurements taken by optically based metrology systems. Structural irregularities such as roughness and topographical errors give rise to light scattered outside of the specularly reflected component of the diffracted light. The scattered light interferes constructively or destructively with the specular component in a high numerical aperture illumination and detection system to form a speckle field. Various methods of determining residual signals indicative of the speckle field are presented. Furthermore, various methods of determining structural irregularities based on analysis of the residual signals are presented. In various embodiments, illumination with a high degree of spatial coherence is provided over any of a wide range of angles of incidence, multiple polarization channels, and multiple wavelength channels.

Abstract: The disclosure is directed to providing high resolution stereoscopy with extended depth of focus. Wave front coding in optical paths going to a first detector and at least a second detector may be implemented to affect an intermediate set of images. The intermediate set of images may be filtered (i.e. decoded) to produce a filtered set of images with selected resolution and depth of focus properties. A first filtered image and a second filtered image may be substantially simultaneously presented to respective first and second eyes of an observer to further generate an illusion of enhanced depth (i.e. 3D perception).