Abstract: A computer-implemented method for determining an optimized purge gas flow in a semi-conductor inspection metrology or lithography apparatus, comprising receiving a permissible contaminant mole fraction, a contaminant outgassing flow rate associated with a contaminant, a contaminant mass diffusivity, an outgassing surface length, a pressure, a temperature, a channel height, and a molecular weight of a purge gas, calculating a flow factor based on the permissible contaminant mole fraction, the contaminant outgassing flow rate, the channel height, and the outgassing surface length, comparing the flow factor to a predefined maximum flow factor value, calculating a minimum purge gas velocity and a purge gas mass flow rate from the flow factor, the contaminant mass diffusivity, the pressure, the temperature, and the molecular weight of the purge gas, and introducing the purge gas into the semi-conductor inspection metrology or lithography apparatus with the minimum purge gas velocity and the purge gas flow rate.

Abstract: Methods and systems for performing semiconductor metrology directly on device structures are presented. A measurement model is created based on measured training data collected from at least one device structure. The trained measurement model is used to calculate process parameter values, structure parameter values, or both, directly from measurement data collected from device structures of other wafers. In some examples, measurement data from multiple targets is collected for model building, training, and measurement. In some examples, the use of measurement data associated with multiple targets eliminates, or significantly reduces, the effect of under layers in the measurement result, and enables more accurate measurements. Measurement data collected for model building, training, and measurement may be derived from measurements performed by a combination of multiple, different measurement techniques.

Abstract: Metrology methods and respective software and module are provided, which identify and remove measurement inaccuracy which results from process variation leading to target asymmetries. The methods comprise identifying an inaccuracy contribution of process variation source(s) to a measured scatterometry signal (e.g., overlay) by measuring the signal across a range of measurement parameter(s) (e.g., wavelength, angle) and targets, and extracting a measurement variability over the range which is indicative of the inaccuracy contribution. The method may further assume certain functional dependencies of the resulting inaccuracy on the target asymmetry, estimate relative donations of different process variation sources and apply external calibration to further enhance the measurement accuracy.

Abstract: A reticle is inspected with an imaging system to obtain a measured image of a structure on the reticle, and the structure has an unknown critical dimension (CD). Using a model, a calculated image is generated using a design database that describes a pattern used to form the structure on the reticle. The model generates the calculated image based on: optical properties of reticle materials of the structure, a computational model of the imaging system, and an adjustable CD. A norm of a difference between the measured and calculated images is minimized by adjusting the adjustable CD and iteratively repeating the operation of generating a calculated image so as to obtain a final CD for the unknown CD of the structure. Minimizing the norm of the difference is performed simultaneously with respect to the adjustable CD and one or more uncertain parameters of the imaging system.

Abstract: Disclosed are methods and apparatus for inspecting a semiconductor sample. This system comprises an illumination optics subsystem for generating and directing an incident beam towards a defect on a surface of a wafer. The illumination optics subsystem includes a light source for generating the incident beam and one or more polarization components for adjusting a ratio and/or a phase difference for the incident beam's electric field components. The system further includes a collection optics subsystem for collecting scattered light from the defect and/or surface in response to the incident beam, and the collection optics subsystem comprises an adjustable aperture at the pupil plane, followed by a rotatable waveplate for adjusting a phase difference of electric field components of the collected scattered light, followed by a rotatable analyzer.

Abstract: Methods and systems for minimizing of algorithmic inaccuracy in scatterometry overlay (SCOL) metrology are provided. SCOL targets are designed to limit the number of oscillation frequencies in a functional dependency of a resulting SCOL signal on the offset and to reduce the effect of higher mode oscillation frequencies. The targets are segmented in a way that prevents constructive interference of high modes with significant amplitudes, and thus avoids the inaccuracy introduced by such terms into the SCOL signal. Computational methods remove residual errors in a semi-empirical iterative process of compensating for the residual errors algorithmically or through changes in target design.

Abstract: A device and method for surface height profiling are presented. The device has a source with a source slit through which light is provided. The device includes an objective lens having a reference surface. The objective lens is configured to illuminate a sample with test light from the source and to combine test light reflected from the sample with reference light reflected from the reference surface to form combined light. A spectrometer is positioned to receive the combined light at an entrance slit. The spectrometer is configured to image the combined light as a 2D image with a wavelength dimension and a spatial position dimension. A processor in electrical communication with the spectrometer is programmed to receive a signal representing the 2D image and to determine a surface height profile of the sample based on the signal.

Abstract: Systems and methods for providing improved wafer geometry measurements are disclosed. A wafer geometry measurement system may utilize techniques that enable the wafer geometry measurement system to identify and reduce wafer surface errors caused by structures such as patterns on the wafers being measured. The wafer geometry measurement system may also utilize techniques that enable the wafer geometry measurement system to accurately reconstruct patterned wafer surfaces.

Abstract: Metrology targets and methods are provided, which provide self-Moiré measurements of unresolved target features, i.e., interaction of electromagnetic fields re-scattered off elements within a single target layer provides signals with Moiré pitches that are measurable, although the actual target pitches are unresolved and possibly device-like. Targets comprise cell(s) with interlaced lines of elements having different device-like pitches which are selected to yield resolved Moiré pitch(es). Different target designs are presented for scatterometry and imaging metrology measurements, as well as for critical dimension, dose and focus, and pitch walk measurements—of device-like targets.

Abstract: Methods and systems for dynamic design attributes for wafer inspection are provided. One method includes, at run time of a wafer inspection recipe, prompting a user of a wafer inspection tool on which the wafer inspection recipe is performed for information for a design based binning (DBB) process. The information includes one or more formulae for calculating design attributes from a design for a wafer. The design attributes are used to bin the defects in the DBB process. The method also includes performing inspection of a wafer according to an updated wafer inspection recipe. Performing the inspection includes binning defects detected on the wafer according to the DBB process in the updated wafer inspection recipe.

Abstract: The broadband light source includes a gas containment structure and a pump laser for generating a pump beam including illumination of a wavelength near that of a weak absorption line of a neutral gas contained in the gas containment structure. The broadband light source also includes anamorphic optics for focusing the pump beam into an elliptical beam waist positioned in or near the center of the gas containment structure. The broadband light source also includes collection optics for collecting broadband radiation emitted by the plasma in a direction aligned with a longer axis of the elliptical beam waist.

Abstract: Disclosed are methods and apparatus for facilitating an inspection of a sample using an inspection tool. An inspection tool is used to obtain an image or signal from an EUV reticle that specifies an intensity variation across the EUV reticle, and this intensity variation is converted to a CD variation that removes a flare correction CD variation so as to generate a critical dimension uniformity (CDU) map without the flare correction CD variation. This removed flare correction CD variation originates from design data for fabricating the EUV reticle, and such flare correction CD variation is generally designed to compensate for flare differences that are present across a field of view (FOV) of a photolithography tool during a photolithography process. The CDU map is stored in one or more memory devices and/or displayed on a display device, for example, of the inspection tool or a photolithography system.

Abstract: A spot scanning imaging system with run-time alignment includes a beam scanning device configured to linearly scan a focused beam of illumination across a sample, one or more detectors positioned to receive light from the sample, and a controller communicatively coupled to the beam scanning apparatus, the sample stage, and the one or more detectors. The controller is configured to store a first image, transmit a set of drive signals to at least one of the beam scanning device, the sample stage, or the one or more detectors, compare at least a portion of the second sampling grid to at least a portion of the first sampling grid to determine one or more offset errors, and adjust at least one drive signal in the set of drive signals based on the one or more offset errors such that the second sample grid overlaps the first sample grid.

Abstract: Disclosed are methods and apparatus for detecting defects or reviewing defects in a semiconductor sample. The system has a brightfield (BF) module for directing a BF illumination beam onto a sample and detecting an output beam reflected from the sample in response to the BF illumination beam. The system has a modulated optical reflectance (MOR) module for directing a pump and probe beam to the sample and detecting a MOR output beam from the probe spot in response to the pump beam and the probe beam. The system includes a processor for analyzing the BF output beam from a plurality of BF spots to detect defects on a surface or near the surface of the sample and analyzing the MOR output beam from a plurality of probe spots to detect defects that are below the surface of the sample.

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: A rotatable compensator configured to transmit non-collimated light over a broad range of wavelengths, including ultraviolet, with a high degree of retardation uniformity across the aperture is presented. In one embodiment, a rotatable compensator includes a stack of four individual plates in optical contact. The two thin plates in the middle of the stack are made from a birefringent material and are arranged to form a compound, zeroth order bi-plate. The remaining two plates are relatively thick and are made from an optically isotropic material. These plates are disposed on either end of the compound, zeroth order bi-plate. The low order plates minimize the sensitivity of retardation across the aperture to non-collimated light. Materials are selected to ensure transmission of ultraviolet light. The optically isotropic end plates minimize coherence effects induced at the optical interfaces of the thin plates.

Abstract: Pixel aperture size adjustment in a linear sensor is achieved by applying more negative control voltages to central regions of the pixel's resistive control gate, and applying more positive control voltages to the gate's end portions. These control voltages cause the resistive control gate to generate an electric field that drives photoelectrons generated in a selected portion of the pixel's light sensitive region into a charge accumulation region for subsequent measurement, and drives photoelectrons generated in other portions of the pixel's light sensitive region away from the charge accumulation region for subsequent discard or simultaneous readout. A system utilizes optics to direct light received at different angles or locations from a sample into corresponding different portions of each pixel's light sensitive region.

Abstract: Systems and methods to control particle generation in a reticle inspection system are presented. The number of particles added to a reticle during an entire load-inspect-unload sequence of a reticle inspection system is reduced by performing all reticle contact events in a controlled, flowing air environment. In one embodiment, the reticle is fixed to a carrier by clamping outside of the vacuum environment, and the carrier, rather than the reticle, is coupled to the reticle stage of the inspection system. In this manner, the high levels of back-side particulation associated with electrostatic chucking are avoided. In addition, the carrier is configured to be coupled to the reticle stage in any of four different orientations separated by ninety degrees.

Abstract: Methods and metrology modules and tools are provided, which minimize an estimated overlay variation measure at misalignment vector values obtained from a derived functional form of an overlay linear response to non-periodic effects. Provided methods further quantifying target noise due to the non-periodic effects using multiple repeated overlay measurements of the target cells, calculating an ensemble of overlay measurements between the cells over the multiple measurement repeats and expressing the target noise as a statistical derivative of the calculated overlay measurements. Sub-ensembles may be selected to further characterize the target noise. Various outputs include optimized scanning patterns, target noise metrics and recipe and target optimization.

Abstract: Methods and systems for detecting defects on a wafer using defect-specific and multi-channel information are provided. One method includes acquiring information for a target on a wafer. The target includes a pattern of interest (POI) formed on the wafer and a known defect of interest (DOI) occurring proximate to or in the POI. The method also includes detecting the known DOI in target candidates by identifying potential DOI locations based on images of the target candidates acquired by a first channel of an inspection system and applying one or more detection parameters to images of the potential DOI locations acquired by a second channel of the inspection system. Therefore, the image(s) used for locating potential DOI locations and the image(s) used for detecting defects can be different.