Interferometric characterization of surface topography
Granted: November 26, 2019
Patent Number:
10488184
An interferometric metrology device characterizes a surface topography of a sample at different length scales by combining the interferometric data into blocks of different length scales or by filtering the interferometric data at different length scales and then determining statistical moments or surface properties of the surface topography at the different length scales. The interferometric metrology device determines a best focus position for a processing tool based on different…
Local purge within metrology and inspection systems
Granted: October 22, 2019
Patent Number:
10451542
A purge system includes a purge gas distribution manifold that includes at least one port through which light beam from an optical metrology or inspection head is transmitted. The purge gas distribution manifold includes a bottom surface having one or more apertures through which purge gas is expelled. The bottom surface is held in close proximity to the top surface of the substrate and the apertures may be distributed over the bottom surface of the purge gas distribution manifold so…
Correction of angular error of plane-of-incidence azimuth of optical metrology device
Granted: May 21, 2019
Patent Number:
10296554
Optical metrology is used to calibrate the plane-of-incidence (POI) azimuth error by determining and correcting an azimuth angle offset. The azimuth angle offset may be determined by measuring at least a partial Mueller matrix from a calibration grating on a sample held on a stage for a plurality of POI azimuth angles. An axis of symmetry is determined for a curve describing a value of a Mueller matrix element with respect to POI azimuth angle, for each desired wavelength and each…
Scanning white-light interferometry system for characterization of patterned semiconductor features
Granted: May 14, 2019
Patent Number:
10288408
A white light interferometric metrology device operates in the image plane and objective pupil plane. The interferometric metrology device extracts the electric field with complex parameters and that is a function of azimuth angle, angle of incidence and wavelength from interferometric data obtained from the pupil plane. Characteristics of the sample are determined using the electric field based on an electric field model of the azimuth angle, the angle of incidence and the wavelength…
Deconvolution to reduce the effective spot size of a spectroscopic optical metrology device
Granted: April 30, 2019
Patent Number:
10274367
The effective spot size of a spectroscopic metrology device is reduced through deconvolution of a measurement spectra set acquired from a measurement target combined with a training spectra set obtained from a training target. The measurement spectra set may be obtained using sparse sampling of a grid scan of a measurement target. The training spectra set is obtained from a grid scan of a training target that is similar to the measurement target. The training spectra set and the…
Via characterization for BCD and depth metrology
Granted: April 9, 2019
Patent Number:
10254110
An optical metrology device determines physical characteristics of at least one via in a sample, such as a through-silicon vias (TSV), using signal strength data for modeling of the bottom critical dimension (BCD) and/or for refinement of the data used to determine a physical characteristic of the via, such as BCD and/or depth. The metrology device obtains interferometric data and generates height and signal strength data, from which statistical properties may be obtained. The height and…
Image based overlay measurement with finite gratings
Granted: October 23, 2018
Patent Number:
10107621
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…
Optical metrology with purged reference chip
Granted: September 25, 2018
Patent Number:
10082461
An integrated metrology module includes a chuck for holding a sample and positioning the sample with respect to an optical metrology device, a reference chip for the optical metrology device, the reference chip being movable to various positions with respect to the optical metrology device, and a reference chip purge device provides a flow of purge gas or air over the reference chip while the reference chip is in the various positions. The reference chip purge device may be static or…
3D target for monitoring multiple patterning process
Granted: August 28, 2018
Patent Number:
10061210
A metrology target is designed for monitoring variations in a multiple patterning process, such as a self-aligned doubled patterning (SADP) or self-aligned quadruple patterning (SAQP) process. The metrology target may include a plurality of sub-patterns. For example, the metrology target may be a three-dimensional (3D) target rather than a conventional two-dimensional line-space target design. The 3D target design includes multiple sub-patterns arranged with a pitch in a direction that…
Optical metrology using differential fitting
Granted: June 12, 2018
Patent Number:
9995689
Parameters of a sample are measured using a model-based approach that utilizes the difference between experimental spectra acquired from the sample and experimental anchor spectra acquired from one or more reference samples at the same optical metrology tool. Anchor parameters of the one or more reference samples are determined using one or more reference optical metrology tools. The anchor spectrum is obtained and the target spectrum for the sample is acquired using the optical…
Protected lens cover plate for an optical metrology device
Granted: May 1, 2018
Patent Number:
9958673
A cover plate or lens for an optical metrology device that is positioned under a wafer during measurement is protected with a purge device. The purge device may include a ring that extends around a periphery of the cover plate or lens. The ring includes a plurality of apertures through which a purge gas or air is expelled over the surface of the cover plate or lens. Additionally or alternatively, one or more heating elements may be provided that extend around the periphery of the cover…
Deconvolution to reduce the effective spot size of a spectroscopic optical metrology device
Granted: May 1, 2018
Patent Number:
9958327
The effective spot size of a spectroscopic metrology device is reduced through deconvolution of a measurement spectra set acquired from a measurement target combined with a training spectra set obtained from a training target. The measurement spectra set may be obtained using sparse sampling of a grid scan of a measurement target. The training spectra set is obtained from a grid scan of a training target that is similar to the measurement target. The training spectra set and the…
Focusing system with filter for open or closed loop control
Granted: February 27, 2018
Patent Number:
9903806
An optical metrology device, such as an ellipsometer, includes a focusing system that adjusts the focal position of the metrology device in real time so that focus may be maintained during movement of the measurement locations on the sample, e.g., using closed loop control. A filtered focus signal may be used to adjust the focal position while moving to a measurement location. Additionally, the focus signal may be coarsely filtered and finely filtered, where a coarse filtered focus…
Optical metrology system for spectral imaging of a sample
Granted: December 19, 2017
Patent Number:
9846122
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 collects the photoluminescence light emitted along the…
Optical critical dimension target design
Granted: November 21, 2017
Patent Number:
9824176
A measurement target for a semiconductor device is designed. The semiconductor device includes a structure to be measured that has a spectrum response that is comparable to or below system noise level for an optical critical dimension measurement device to be used to measure the structure. The measurement target is designed by obtaining a process window and design rules for the semiconductor device and determining prospective pitches through modeling to identify pitches that produce a…
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.…
