Nanometrics Patent Grants

Simultaneous measurement of multiple overlay errors using diffraction based overlay

Granted: January 17, 2017
Patent Number: 9547244
A plurality of overlay errors in a structure is determined using a target that includes a plurality of diffraction based overlay pads. Each diffraction based overlay pad has the same number of periodic patterns as the structure under test. Additionally, each diffraction based overlay pad includes a programmed shift between each pair of periodic patterns. The pads are illuminated and the resulting light is detected and used to simultaneously determine the plurality of overlay errors in…

Ellipsometer focusing system

Granted: January 26, 2016
Patent Number: 9243999
An ellipsometer includes an integrated focusing system with a beam splitter between the sample and the ellipsometer detector. The beam splitter provides a portion of the radiation to a lens system that magnifies any deviation from a best focus position by at least 2×. The focusing system includes a 2D sensor, where the spot of light focused on the sensor is 50 percent or smaller than the sensor. The focusing system may further include a compensator to correct optical aberrations caused…

Diffraction based overlay linearity testing

Granted: January 19, 2016
Patent Number: 9239523
An empirical diffraction based overlay (eDBO) measurement of an overlay error is produced using diffraction signals from a plurality of diffraction based alignment pads from an alignment target. The linearity of the overlay error is tested using the same diffraction signals or a different set of diffraction signals from diffraction based alignment pads. Wavelengths that do not have a linear response to overlay error may be excluded from the measurement error.

Optical metrology system for spectral imaging of a sample

Granted: November 10, 2015
Patent Number: 9182351
An optical metrology device is capable of detection of any combination of photoluminescence light, specular reflection of broadband light, and scattered light from a line across the width of a sample. The metrology device includes a first light source that produces a first illumination line on the sample. A scanning system may be used to scan an illumination spot across the sample to form the illumination line. A detector spectrally images the photoluminescence light emitted along the…

Optical metrology with multiple angles of incidence and/or azimuth angles

Granted: August 25, 2015
Patent Number: 9115987
An optical metrology device simultaneously detects light with multiple angles of incidence (AOI) and/or multiple azimuth angles to determine at least one parameter of a sample. The metrology device focuses light on the sample using an optical system with a large numerical aperture, e.g., 0.2 to 0.9. Multiple channels having multiple AOIs and/or multiple azimuth angles are selected simultaneously by passing light reflected from the sample through a plurality of pupils in a pupil plate.…

Apparatus and method for electrical characterization by selecting and adjusting the light for a target depth of a semiconductor

Granted: August 18, 2015
Patent Number: 9110127
The present disclosure provides methods and apparatus that enable characterization of an electrical property of a semiconductor specimen, e.g., dopant concentration of a near-surface region of the specimen. In exemplary method, a target depth for measurement is selected. This thickness may, for example, correspond to a nominal production thickness of a thin active device region of the specimen. A light is adjusted to an intensity selected to characterize a target region of the specimen…

Simultaneous measurement of multiple overlay errors using diffraction based overlay

Granted: April 14, 2015
Patent Number: 9007584
A plurality of overlay errors in a structure is determined using a target that includes a plurality of diffraction based overlay pads. Each diffraction based overlay pad has the same number of periodic patterns as the structure under test. Additionally, each diffraction based overlay pad includes a programmed shift between each pair of periodic patterns. The pads are illuminated and the resulting light is detected and used to simultaneously determine the plurality of overlay errors in…

Automated system check for metrology unit

Granted: September 2, 2014
Patent Number: 8825444
A metrology unit includes an integrated reference target with which an automated system check process is performed. The automated system check process includes measuring a feature on the reference target and determining if the measurement is within a desired specification for the metrology unit. When the metrology unit fails the automated system check, or if otherwise warranted, an automated diagnosis process may be performed using the same integrated reference target. The automated…

Dark field diffraction based overlay

Granted: August 26, 2014
Patent Number: 8817273
A dark field diffraction based overlay metrology device illuminates an overlay target that has at least three pads for an axis, the three pads having different programmed offsets. The overlay target may be illuminated using two obliquely incident beams of light from opposite azimuth angles or using normally incident light. Two dark field images of the overlay target are collected using ±1st diffraction orders to produce at least six independent signals. For example, the +1st diffraction…

Thin films and surface topography measurement using reduced library

Granted: August 26, 2014
Patent Number: 8818754
The properties of a surface of an object in presence of thin transparent films are determined by generating a library of model signals and processing a measurement signal via searching the library to evaluate films properties and topography. The library may be reduced with principal component analysis to enhance computation speed. Computation enhancement may also be achieved by removal of the height contributions from the signal leaving only the film contribution in the signal. The film…

Ellipsometer focusing system

Granted: October 15, 2013
Patent Number: 8559008
An ellipsometer includes an integrated focusing system with a beam splitter between the sample and the ellipsometer detector. The beam splitter provides a portion of the radiation to a lens system that magnifies any deviation from a best focus position by at least 2×. The focusing system includes a 2D sensor, where the spot of light focused on the sensor is 50 percent or smaller than the sensor. The focusing system may further include a compensator to correct optical aberrations caused…

Capacitive displacement transducer for a weak-motion inertial sensor

Granted: October 1, 2013
Patent Number: 8544325
A broadband weak-motion inertial sensor includes a frame, a movable inertial mass, a forcing transducer for keeping the inertial mass stationary relative to the frame during operation, and a flexure for suspending the movable mass in the frame. Two or more closely spaced, substantially parallel capacitor plates, at least one attached to the frame, and one attached to the movable inertial mass, form a capacitive displacement transducer. The capacitor plates have a plurality of apertures…

Local stress measurement

Granted: September 17, 2013
Patent Number: 8534135
An optical metrology device determines the local stress in a film on a substrate. The metrology device maps the thickness of the substrate prior to processing. After processing, the metrology device determines the surface curvature of the substrate caused by the processing and maps the thickness of a film on the top surface after of the substrate after processing. The surface curvature of the substrate may be determined as basis functions. The local stress in the film is then determined…

Scatterometry measurement of asymmetric structures

Granted: September 3, 2013
Patent Number: 8525993
Asymmetry metrology is performed using at least a portion of Mueller matrix elements, including, e.g., the off-diagonal elements of the Mueller matrix. The Mueller matrix may be generated using, e.g., a spectroscopic or angle resolved ellipsometer that may include a rotating compensator. The Mueller matrix is analyzed by fitting at least a portion of the elements to Mueller matrix elements calculated using a rigorous electromagnetic model of the sample or by fitting the off-diagonal…

Measurement of a sample using multiple models

Granted: August 6, 2013
Patent Number: 8501501
A sample with at least a first structure and a second structure is measured and a first model and a second model of the sample are generated. The first model models the first structure as an independent variable and models the second structure. The second model of the sample models the second structure as an independent variable. The measurement, the first model and the second model together to determine at least one desired parameter of the sample. For example, the first structure may…

In-plane optical metrology

Granted: June 11, 2013
Patent Number: 8462345
A structure that is located adjacent to a measurement target on a substrate is used to convert incident radiation from an optical metrology device to be in-plane with the measurement target. The structure may be, e.g., a grating or photonic crystal, and may include a waveguide between the structure and the measurement target. The in-plane light interacts with the measurement target and is reflected back to the structure, which converts the in-plane light to out-of-plane light that is…

Mueller matrix spectroscopy using chiroptic

Granted: April 23, 2013
Patent Number: 8427645
An optical metrology device produces a broadband beam of light that is incident on and reflected by a sample and introduces multiple variations in the polarization state of the beam of light induced by an optical chiral element. Using the detected light, the Muller matrix or partial Mueller matrix for the sample is determined, which is then used to determine a characteristic of the sample. For example, simulated spectra for a Mueller matrix for a model is fit to the measured spectra for…

Optical metrology on textured samples

Granted: February 19, 2013
Patent Number: 8379227
One or more parameters of a sample that includes a textured substrate and one or more overlying films is determined using, e.g., an optical metrology device to direct light to be incident on the sample and detecting light after the incident light interacts with the sample. The acquired data is normalized using reference data that is produced using a textured reference sample. The normalized data is then fit to simulated data that is associated with a model having an untextured substrate…

Multilayer alignment and overlay target and measurement method

Granted: December 25, 2012
Patent Number: 8339605
A target system for determining positioning error between lithographically produced integrated circuit fields on at least one lithographic level. The target system includes a first target pattern on a lithographic field containing an integrated circuit pattern, with the first target pattern comprising a plurality of sub-patterns symmetric about a first target pattern center and at a same first distance from the first target pattern center. The target system also includes a second target…

Silicon filter for photoluminescence metrology

Granted: December 11, 2012
Patent Number: 8330946
A method and apparatus identifies defects in a sample using photoluminescence with a silicon filter to filter out the primary excitation light from the return light received by the detector. The silicon filter passes the light emitted by the sample in response to the excitation light, while absorbing the lower wavelength excitation light that is reflected by or transmitted through the sample. The silicon filter has introduced impurities that reduce the recombination lifetime which…