Measurement methodology of advanced nanostructures
Granted: October 26, 2021
Patent Number:
11156548
A parameterized geometric model of a structure can be determined based on spectra from a wafer metrology tool. The structure can have geometry-induced anisotropic effects. Dispersion parameters of the structure can be determined from the parameterized geometric model. This can enable metrology techniques to measure nanostructures that have geometries and relative positions with surrounding structures that induce non-negligible anisotropic effects. These techniques can be used to…
Cross layer common-unique analysis for nuisance filtering
Granted: October 19, 2021
Patent Number:
11151711
Common events between layers on a semiconductor wafer are filtered. Common events should contain the majority of defects of interest. Only nuisance events that are common between layers on the semiconductor wafer remain, which reduces the nuisance rate. Defects that are common across layers can be filtered based on, for example, defect coordinates, a difference image, or defect attributes.
Process monitoring of deep structures with X-ray scatterometry
Granted: October 12, 2021
Patent Number:
11145559
Methods and systems for estimating values of process parameters, structural parameters, or both, based on x-ray scatterometry measurements of high aspect ratio semiconductor structures are presented herein. X-ray scatterometry measurements are performed at one or more steps of a fabrication process flow. The measurements are performed quickly and with sufficient accuracy to enable yield improvement of an on-going semiconductor fabrication process flow. Process corrections are determined…
System, method and non-transitory computer readable medium for tuning sensitivities of, and determining a process window for, a modulated wafer
Granted: October 5, 2021
Patent Number:
11139216
A system, method, and non-transitory computer readable medium are provided for tuning sensitivities of, and determining a process window for, a modulated wafer. The sensitivities for dies of the modulated wafer are tuned dynamically based on a single set of parameters. Further, the process window is determined for the modulated wafer from prior determined parameter-specific nominal process windows.
Differential imaging for single-path optical wafer inspection
Granted: October 5, 2021
Patent Number:
11138722
Methods and systems for enhanced defect detection based on images collected by at least two imaging detectors at different times are described. In some embodiments, the time between image measurements is at least 100 microseconds and no more than 10 milliseconds. In one aspect, one or more defects of interest are identified based on a composite image of a measured area generated based on a difference between collected images. In a further aspect, measurement conditions associated with…
Metrology targets and methods with oblique periodic structures
Granted: October 5, 2021
Patent Number:
11137692
Metrology targets, design methods and measurement methods thereof are provided with periodic structure(s) which are oblique with respect to orthogonal production axes X and Y of the lithography tool—enabling more accurate overlay measurements of devices having diagonal (oblique, tilted) elements such as DRAM devices. One or more oblique periodic structure(s) may be used to provide one- or two-dimensional signals, with respect to one or more layers, possibly providing overlay…
Apparatus and methods for measuring phase and amplitude of light through a layer
Granted: September 28, 2021
Patent Number:
11131629
In one embodiment, disclosed are apparatus, methods, and targets for determining a phase shift of a photomask having a phase-shift target. An inspection or metrology system is used to direct an incident beam towards the target and then detect a plurality of intensity measurements that are transmitted through the target in response to the incident beam. A phase shift value for the target may then be determined based on the intensity measurements.
Defect location accuracy using shape based grouping guided defect centering
Granted: September 14, 2021
Patent Number:
11119060
Defect location accuracy can be increased using shape based grouping with pattern-based defect centering. Design based grouping of defects on a wafer can be performed. A spatial distribution of the defects around at least one structure on the wafer, such as a predicted hot spot, can be determined. At least one design based defect property for a location around the structure can be determined. The defects within an x-direction threshold and a y-direction threshold of the structure may be…
Moiré target and method for using the same in measuring misregistration of semiconductor devices
Granted: September 14, 2021
Patent Number:
11119419
A target for use in the optical measurement of misregistration in the manufacture of semiconductor devices, the target including a first periodic structure formed on a first layer of a semiconductor device and having a first pitch along an axis and a second periodic structure formed on a second layer of the semiconductor device and having a second pitch along the axis, different from the first pitch, the second periodic structure extending beyond the first periodic structure along the…
Hermetic sealing of a nonlinear crystal for use in a laser system
Granted: September 14, 2021
Patent Number:
11119384
Disclosed are methods and apparatus for hermetically sealing a nonlinear optical (NLO) crystal for use in a laser system. A mounted NLO crystal, an enclosure base, a lid, and a plurality of window components are moved into an oven. A vacuum bake process is then performed on the mounted NLO crystal, enclosure base, lid, and plurality of window components until a humidity level that is less than a predefined amount is reached. The mounted NLO crystal, enclosure base, lid, and plurality of…
Back-illuminated sensor and a method of manufacturing a sensor
Granted: September 7, 2021
Patent Number:
11114489
An image sensor for electrons or short-wavelength light includes a semiconductor membrane, circuit elements formed on one surface of the semiconductor membrane, and a pure boron layer on the other surface of the semiconductor membrane. The circuit elements are connected by metal interconnects comprising a refractory metal. An anti-reflection or protective layer may be formed on top of the pure boron layer. This image sensor has high efficiency and good stability even under continuous use…
Mitigation of inaccuracies related to grating asymmetries in scatterometry measurements
Granted: September 7, 2021
Patent Number:
11112704
Scatterometry overlay targets as well as target design and measurement methods are provided, which mitigate the effects of grating asymmetries in diffraction based overlay measurements. Targets comprise additional cells with sub-resolved structures replacing resolved coarse pitch gratings and/or comprise alternating sub-resolved structures with coarse pitch periodicity—to isolate and remove inaccuracies that result from grating asymmetries. Measurement methods utilize orthogonally…
Hybrid overlay target design for imaging-based overlay and scatterometry-based overlay
Granted: September 7, 2021
Patent Number:
11112369
Designs for a hybrid overlay target design that includes a target area with both an imaging-based target and a scatterometry-based target are disclosed. The imaging-based overlay target design can include side-by-side grating structure. A scatterometry-based overlay target design at a different location in the target area can include grating-over-grating structure. A method of measuring the hybrid overlay target design and a system with both an imaging optical system and a scatterometry…
Charge control device for a system with multiple electron beams
Granted: August 10, 2021
Patent Number:
11087950
Systems and methods to focus and align multiple electron beams are disclosed. A camera produces image data of light from electron beams that is projected at a fiber optics array with multiple targets. An image processing module determines an adjustment to a voltage applied to a relay lens, a field lens, or a multi-pole array based on the image data. The adjustment minimizes at least one of a displacement, a defocus, or an aberration of one of the electron beams. Using a control module,…
Optimizing computational efficiency by multiple truncation of spatial harmonics
Granted: August 10, 2021
Patent Number:
11086288
Methods and systems for solving measurement models of complex device structures with reduced computational effort and memory requirements are presented. The computational efficiency of electromagnetic simulation algorithms based on truncated spatial harmonic series is improved for periodic targets that exhibit a fundamental spatial period and one or more approximate periods that are integer fractions of the fundamental spatial period. Spatial harmonics are classified according to each…
Photocathode including silicon substrate with boron layer
Granted: August 3, 2021
Patent Number:
11081310
A photocathode is formed on a monocrystalline silicon substrate having opposing illuminated (top) and output (bottom) surfaces. To prevent oxidation of the silicon, a thin (e.g., 1-5 nm) boron layer is disposed directly on the output surface using a process that minimizes oxidation and defects. An optional second boron layer is formed on the illuminated (top) surface, and an optional anti-reflective material layer is formed on the second boron layer to enhance entry of photons into the…
Hybrid overlay target design for imaging-based overlay and scatterometry-based overlay
Granted: August 3, 2021
Patent Number:
11079335
Designs for a hybrid overlay target design that includes a target area with both an imaging-based target and a scatterometry-based target are disclosed. The imaging-based overlay target design can include side-by-side grating structure. A scatterometry-based overlay target design at a different location in the target area can include grating-over-grating structure. A method of measuring the hybrid overlay target design and a system with both an imaging optical system and a scatterometry…
Misregistration measurements using combined optical and electron beam technology
Granted: July 27, 2021
Patent Number:
11075126
A misregistration metrology system useful in manufacturing semiconductor device wafers including an optical misregistration metrology tool configured to measure misregistration at at least one target between two layers of a semiconductor device which is selected from a batch of semiconductor device wafers which are intended to be identical, an electron beam misregistration metrology tool configured to measure misregistration at the at least one target between two layers of a…
Methods and systems for characterization of an x-ray beam with high spatial resolution
Granted: July 27, 2021
Patent Number:
11073487
Methods and systems for positioning a specimen and characterizing an x-ray beam incident onto the specimen in a Transmission, Small-Angle X-ray Scatterometry (T-SAXS) metrology system are described herein. A specimen positioning system locates a wafer vertically and actively positions the wafer in six degrees of freedom with respect to the x-ray illumination beam without attenuating the transmitted radiation. In some embodiments, a cylindrically shaped occlusion element is scanned across…
High accuracy of relative defect locations for repeater analysis
Granted: July 20, 2021
Patent Number:
11067516
Methods and systems for transforming positions of defects detected on a wafer are provided. One method includes aligning output of an inspection subsystem for a first frame in a first swath in a first die in a first instance of a multi-die reticle printed on the wafer to the output for corresponding frames, swaths, and dies in other reticle instances printed on the wafer. The method also includes determining different swath coordinate offsets for each of the frames, respectively, in the…
