Nanometrics Incorporated Patent applications |
Patent application number | Title | Published |
20150153165 | OPTICAL METROLOGY WITH MULTIPLE ANGLES OF INCIDENCE AND/OR AZUMITH ANGLES - 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. Beamlets produced by the plurality of pupils are detected, e.g., with one or more spectrophotometers, to produce data for the multiple AOIs and/or multiple azimuth angles. The data for multiple AOI and/or multiple azimuth angles may then be processed to determine at least one parameter of the sample, such as profile parameters or overlay error. | 06-04-2015 |
20150146193 | OPTICAL METROLOGY SYSTEM FOR SPECTRAL IMAGING OF A SAMPLE - 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 illumination line. Additionally, a broadband illumination source may be used to produce a second illumination line on the sample, where the detector spectrally images specular reflection of the broadband illumination along the second illumination line. The detector may also image scattered light from the first illumination line. The illumination lines may be scanned across the sample so that all positions on the sample may be measured. | 05-28-2015 |
20140098369 | ELLIPSOMETER FOCUSING SYSTEM - 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 by the beam splitter. A processor receives an image signal and finds the location of the spot from which focus error can be determined and used to correct the focal position of the ellipsometer. The processor compensates for movement of the spot caused by rotating optics. Additionally, a proportional-integral-derivative controller may be used to control exposure time and/or gain of the camera. | 04-10-2014 |
20130278942 | DARK FIELD DIFFRACTION BASED OVERLAY - 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 ±1 | 10-24-2013 |
20130257270 | PLASMA LAMP IGNITION SOURCE - A plasma lamp includes a capsule with a gas contained within the capsule and an ignition source to ionize the gas to produce a light emitting plasma. The ignition source includes field defining conductors within the capsule and a radio frequency source external to the capsule. The radio frequency source and the field defining conductors are configured so that the field defining conductors will produce electric fields in response to RF energy from the radio frequency source and the electric field ionizes at least a portion of the gas. | 10-03-2013 |
20130242303 | DUAL ANGLES OF INCIDENCE AND AZIMUTH ANGLES OPTICAL METROLOGY - A dual optical metrology system includes a first metrology device and a second metrology device, each producing light at different oblique angles of incidence on the same spot of a sample from different azimuth angles. The dual optical metrology system further includes a rotating stage or flip mirrors capable of altering the orientation of the light beams so the first and second metrology devices can measure the same spot on the sample at different orientations. Thus, the first and second metrology devices generate first and second sets of optical metrology data, respectively, at a first orientation with respect to the sample. After the sample is rotated, the first and second metrology devices generate third and fourth sets of optical metrology data. The first, second, third, and fourth sets of data can then be used to determine one or more parameters of the sample. | 09-19-2013 |
20130208279 | IMAGE BASED OVERLAY MEASUREMENT WITH FINITE GRATINGS - An image based overlay measurement is performed using an overlay target that includes shifted overlying gratings. The overlay target is imaged and an asymmetry is measured in the image of the overlaid gratings. The asymmetry is used to determine the overlay error. For each measurement direction, the overlay target may include two or more overlay measurement pads with different offsets between the top and bottom gratings. The measured asymmetries and offsets in the overlay measurement pads may be used to determine the overlay error, e.g., using self-calibration. The pitch and critical dimensions of the overlay target may be optimized to produce a greatest change of symmetry with overlay error for a numerical aperture and wavelength of light used by the image based metrology device. | 08-15-2013 |
20120276665 | APPARATUS AND METHOD FOR ELECTRICAL CHARACTERIZATION BY SELECTING AND ADJUSTING THE LIGHT FOR A TARGET DEPTH OF A SEMICONDUCTOR - 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 having a thickness no greater than the target depth and a surface of the specimen is illuminated with the light. An AC voltage signal induced in the specimen by the light is measured and this AC voltage may be used to quantify an aspect of the electrical property, e.g., to determine dopant concentration, of the target region. | 11-01-2012 |
20120271591 | Thin Films And Surface Topography Measurement Using Reduced Library - 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 measurement signal is compared to a library of film signals to determine the film parameters of the sample. The library of film signals is produced by processing each full signal in a library to similarly remove the height contributions leaving only the film contributions. Additionally, a post-analysis process may be applied to properly evaluate local topography. | 10-25-2012 |
20120257200 | Ellipsometer Focusing System - 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 by the beam splitter. A processor receives an image signal and finds the location of the spot from which focus error can be determined and used to correct the focal position of the ellipsometer. The processor compensates for movement of the spot caused by rotating optics. Additionally, a proportional-integral-derivative controller may be used to control exposure time and/or gain of the camera. | 10-11-2012 |
20120224176 | Parallel Acquisition Of Spectra For Diffraction Based Overlay - Spectra for diffraction based overlay (DBO) in orthogonal directions, i.e., along the X-axis and Y-axis, are acquired in parallel. A broadband light source produces unpolarized broadband light that is simultaneously incident on X-axis and Y-axis DBO targets. A polarization separator, such as a Wollaston prism or planar birefringent element, receives diffracted light from the X-axis and Y-axis DBO targets and separates the TE and TM polarization states of the diffracted light. A detector simultaneously detects the TE and TM polarization states of the diffracted light for both the X-axis DBO target and the Y-axis DBO target as a function of wavelength. | 09-06-2012 |
20120176618 | Mueller Matrix Spectroscopy Using Chiroptic - 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 the Mueller matrix of the sample by adjusting the parameters of the model until an acceptable fit between the simulated spectra and measured spectra from the Mueller matrices is produced. The varied parameters are then used as the sample parameters of interested, which can be reported, such as by storing in memory or displaying. | 07-12-2012 |
20120039568 | In-Plane Optical Metrology - 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 received by the optical metrology device. The optical metrology device then uses the information from the received light to determine one or more desired parameters of the measurement target. Additional structures may be used to receive light that is transmitted through or scattered by the measurement target if desired. | 02-16-2012 |
20110265578 | Local Stress Measurement - 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 using the mapped thickness of the substrate, the determined surface curvature, and the mapped thickness of the film. The local stress may be determined using Stoney's equation that is corrected for non-uniform substrate curvature, non-uniform film thickness, and non-uniform substrate thickness. | 11-03-2011 |
20110238365 | Diffraction Based Overlay Linearity Testing - 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. | 09-29-2011 |
20110141460 | Silicon Filter for Photoluminescence Metrology - 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 reduces or eliminate photoluminescence in the silicon filter in response to the excitation light, thereby improving the signal to noise ratio of the signal received by the detector. | 06-16-2011 |
20110096339 | Optical Metrology On Textured Samples - 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 and one or more variable parameters. The value(s) of the one or more variable parameters from the model associated with the simulated data having the best fit is reported as measurement result. | 04-28-2011 |
20110080585 | Scatterometry Measurement of Asymmetric Structures - 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 elements to a calibrated linear response. The use of the Mueller matrix elements in the asymmetry measurement permits, e.g., overlay analysis using in-chip devices thereby avoiding the need for special off-chip targets. | 04-07-2011 |
20100274521 | Simulating Two-Dimensional Periodic Patterns Using Compressed Fourier Space - The process of modeling a complex two-dimensional periodic structure is improved by selectively truncating the Fourier expansion used in the calculation of resulting scatter signature from the model. The Fourier expansion is selectively truncated by determining the contribution for each harmonic order in the Fourier transform of the permittivity function and retaining the harmonic orders with a contribution that is above a threshold. The Fourier space may be compressed so that only the selected harmonic orders are used, thereby reducing the required memory and calculation times. The compressed Fourier space may be used in a real-time analysis of a sample or to generate a library that is used in the analysis of a sample. | 10-28-2010 |
20100156445 | Apparatus and Method for Electrical Characterization by Selecting and Adjusting the Light for a Target Depth of a Semiconductor - 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 having a thickness no greater than the target depth and a surface of the specimen is illuminated with the light. An AC voltage signal induced in the specimen by the light is measured and this AC voltage may be used to quantify an aspect of the electrical property, e.g., to determine dopant concentration, of the target region. | 06-24-2010 |
20100135571 | Method for Evaluating Microstructures on a Workpiece Based on the Orientation of a Grating on the Workpiece - In a measuring system, a method for evaluating parameters of a workpiece includes measuring a periodic structure, such as a grating, on the workpiece to produce image data. An orientation of features in the image data, produced by higher order diffractions from the periodic structure, is identified. An orientation of the periodic structure is determined based on the orientation of the features in the image data. The image data is then modified, based on the orientation of the periodic structure, to correlate with, and for comparison to, simulated image data to ascertain parameters of the workpiece. Alternatively, optical components in the measuring system, or the workpiece itself, are adjusted to provide a desired alignment between the optical components and the periodic structure. A microstructure on the workpiece may then be measured, and the resulting image data may be compared to the simulated image data to ascertain parameters of the microstructure. | 06-03-2010 |
20090296075 | Imaging Diffraction Based Overlay - An overlay error is determined using a diffraction based overlay target by generating a number of narrow band illumination beams that illuminate the overlay target. Each beam has a different range of wavelengths. Images of the overlay target are produced for each different range of wavelengths. An intensity value is then determined for each range of wavelengths. In an embodiment in which the overlay target includes a plurality of measurement pads, which may be illuminated and imaged simultaneously, an intensity value for each measurement pad in each image is determined. The intensity value may be determined statistically, such as by summing, finding the mean or median of the intensity values of pixels in the image. Spectra is then constructed using the determined intensity value, e.g., for each measurement pad. Using the constructed spectra, the overlay error may then be determined. | 12-03-2009 |
20090276198 | Modeling Conductive Patterns Using An Effective Model - A model of a sample with a periodic or non-periodic pattern of conductive and transparent materials is produced based on the effect that the pattern has on TE polarized incident light. The model of the pattern may include a uniform film of the transparent material and an underlying uniform film of the conductive material. When the pattern has periodicity in two directions, the model may include a uniform film of the transparent material and an underlying portion that based on the physical characteristics of the periodic pattern in the TM polarization direction. When the sample includes an underlying periodic pattern that is orthogonal to the top periodic pattern, the sample may be modeled by modeling the physical characteristics of the top periodic pattern and the effect of the bottom periodic pattern. The model may be stored and used to determine a characteristic of the sample. | 11-05-2009 |
20090229997 | Sealing Ring Assembly and Mounting Method - A sealing ring assembly and an improved method for mounting a sealing ring into an electrochemical cell used for Electrochemical Capacitance Voltage (ECV) profiling measurements. The ring is located in a holder having at least one secondary bore providing fluid communication between a forward face of the holder and the central bore of the ring, directed parallel to but tangentially offset relative to the inner wall of the central bore so as to impart a degree of rotational flow to electrolyte entering the sealing ring through the or each secondary bore which effectively removes gas bubbles and refreshes the electrolyte. The holder facilitates ring removal with a much reduced risk of damage to the delicate sealing surface. | 09-17-2009 |
20090190138 | Line Profile Asymmetry Measurement - This disclosure provides methods for measuring asymmetry of features, such as lines of a diffraction grating. On implementation provides a method of measuring asymmetries in microelectronic devices by directing light at an array of microelectronic features of a microelectronic device. The light illuminates a portion of the array that encompasses the entire length and width of a plurality of the microelectronic features. Light scattered back from the array is detected. One or more characteristics of the back-scattered light may be examined by examining data from the complementary angles of reflection. This can be particularly useful for arrays of small periodic structures for which standard modeling techniques would be impractically complex or take inordinate time. | 07-30-2009 |
20090148256 | Support Pin with Dome Shaped Upper Surface - A chuck, which may hold a substrate during stress measurements, includes a number of pins that support the substrate. Each support pin has a dome shaped upper surface that contacts a bottom surface of a substrate when supporting the substrate. The dome shaped upper surface minimizes contact with the substrate as well as assists in maintaining the same contact location with the substrate regardless of substrate shape. The dome shaped upper surface may be formed of a layer of soft material having a high coefficient of static friction to hold the substrate stationary with respect to the pins when the chuck is accelerated moved during or between stress measurements. Additionally, the layer of soft material may be a thin layer that covers a hard internal dome to reduce creep. | 06-11-2009 |
20090116014 | Determining Overlay Error Using an In-chip Overlay Target - Overlay error between two layers on a substrate is measured using an image of an overlay target in an active area of a substrate. The overlay target may be active features, e.g., structures that cause the device to function as desired when manufacturing is complete. The active features may be permanent structures or non-permanent structures, such as photoresist, that are used define the permanent structures during manufacturing. The image of the overlay target is analyzed by measuring the light intensity along one or more scan lines and calculating a symmetry values for the scan lines. Using the symmetry values, the overlay error can be determined. | 05-07-2009 |
20090040613 | In-Plane Optical Metrology - 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 received by the optical metrology device. The optical metrology device then uses the information from the received light to determine one or more desired parameters of the measurement target. Additional structures may be used to receive light that is transmitted through or scattered by the measurement target if desired. | 02-12-2009 |
20090010529 | Method for Automatically De-Skewing of Multiple Layer Wafer for Improved Pattern Recognition - A method for processing wafers includes learning a first pattern at a de-skew site on a first wafer layer, saving the first patterns in a recipe for de-skewing wafers, learning a second pattern at the de-skew site a second wafer layer, and saving the second pattern in the same recipe for de-skewing wafers. Learning the first pattern may include determining a score of uniqueness for the first pattern. The method further includes finding the de-skew site on the second wafer layer using the first pattern before learning the second pattern. Finding the de-skew site includes determining a score of similarity between the first pattern and the second pattern. Learning the second pattern is performed when the score of similarity is less than a threshold value. A recipe for de-skewing wafers includes multiple patterns of a de-skew site of a wafer, wherein the patterns include a first pattern at the de-skew site on a first wafer layer and a second pattern at the de-skew site on a second wafer layer. | 01-08-2009 |
20080217794 | Overlay Measurement Target - In an overlay metrology method used during semiconductor device fabrication, an overlay alignment mark facilitates alignment and/or measurement of alignment error of two layers on a semiconductor wafer structure, or different exposures on the same layer. A target is small enough to be positioned within the active area of a semiconductor device combined with appropriate measurement methods, which result in improved measurement accuracy. | 09-11-2008 |