-
公开(公告)号：US11137350B2
公开(公告)日：2021-10-05
申请号：US16741734
申请日：2020-01-13
Applicant: KLA Corporation
Inventor： David Y. Wang , Shankar Krishnan , Guorong V. Zhuang
IPC: G01N21/35 , G01N21/47 , G01N21/3563 , G01N21/33
Abstract: Methods and systems for performing high throughput spectroscopic measurements of semiconductor structures at mid-infrared wavelengths are presented herein. A Fourier Transform Infrared (FTIR) spectrometer includes one or more measurement channels spanning a wavelength range between 2.5 micrometers and 12 micrometers. The FTIR spectrometer measures a target at multiple different angles of incidence, azimuth angles, different wavelength ranges, different polarization states, or any combination thereof. In some embodiments, illumination light is provided by a laser sustained plasma (LSP) light source to achieve high brightness and small illumination spot size. In some embodiments, FTIR measurements are performed off-axis from the direction normal to the surface of the wafer. In some embodiments, a Stirling cooler extracts heat from the detector of an FTIR spectrometer. In another aspect, measurements performed by one or more spectrometer measurement channels are combined with measurements performed by a mid-infrared FTIR spectrometer channel to characterize high aspect ratio structures.
-
公开(公告)号：US20210242060A1
公开(公告)日：2021-08-05
申请号：US17028878
申请日：2020-09-22
Applicant: KLA Corporation
Inventor： Shankar Krishnan , David Y. Wang , Johannes D. de Veer
Abstract: A metrology system for characterizing a sample formed from a first wafer and a second wafer bonded at an interface with a metrology target near the interface may include a metrology tool and a controller. The metrology tool may include one or more illumination sources and an illumination sub-system to direct illumination from the one or more illumination sources to the metrology target, a detector, and a collection sub-system to collect light from the sample. The light collected from the sample may include light from the metrology target and light from a top surface of the first wafer, and the collection sub-system is may direct the light from the metrology target to the detector. The controller may execute program instructions causing the one or more processors to generate estimates of one or more parameters associated with the sample based on data received from the detector.
-
公开(公告)号：US20250146893A1
公开(公告)日：2025-05-08
申请号：US18936993
申请日：2024-11-04
Applicant: KLA CORPORATION
Inventor： Houssam Chouaib , Zhengquan Tan , Shova Subedi , Shankar Krishnan , David Y. Wang , Oleg Shulepov , Kevin Peterlinz , Natalia Malkova , Dawei Hu , Carlos Ygartua , Isvar Cordova , Eric Cheek , Roman Sappey , Anderson Chou
Abstract: A workpiece is measured using multiple-pass spectroscopic ellipsometry and multi-wavelength Raman spectroscopy, which may be performed in the same system. These measurements are combined to form combined measured data. A stress measurement of the workpiece is determined using the combined measured data. The stress measurement can be determined using a model or a machine learning algorithm.
-
14.发明公开
公开(公告)号：US20240353321A1
公开(公告)日：2024-10-24
申请号：US18136772
申请日：2023-04-19
Applicant: KLA Corporation
Inventor： David Y. Wang , Shankar Krishnan
IPC: G01N21/31 , G01N21/21 , G01N21/95 , G06T7/00 , G06V10/143 , G06V10/145 , G06V10/147 , G06V10/70 , H04N23/11 , H04N25/71
CPC classification number: G01N21/31 , G01N21/211 , G01N21/9505 , G06T7/0004 , G06V10/143 , G06V10/145 , G06V10/147 , G06V10/70 , H04N23/11 , H04N25/71 , G06T2207/20081 , G06T2207/30148
Abstract: Methods and systems for combined Spectroscopic Reflectometry (SR) and Pattern Recognition (PR) based image measurements of semiconductor structures at high throughput are presented herein. Measurements of large pitch targets and thick targets through die with improved fringe contrast, resolution, and spectral fidelity are enabled. A PR based imaging subsystem generates illumination light ranging from visible to short infrared wavelengths. A SR subsystem generates illumination light ranging from the deep ultraviolet to short infrared wavelengths. The SR subsystem includes low Numerical Aperture (NA) optics to realize a relatively large size illumination and collection spot. Both the SR subsystem and the PR based imaging subsystem share the same objective and resolve signals from different depths of a structure under measurement. In some embodiments, a combined machine learning based measurement model estimates values of one or more parameters of interest based on both SR and PR image signals.
-
公开(公告)号：US20230131913A1
公开(公告)日：2023-04-27
申请号：US17541037
申请日：2021-12-02
Applicant: KLA Corporation
Inventor： Shankar Krishnan , David Y. Wang
Abstract: A monolithic optical retarder formed from a monolithic prism may include an input face for receiving a light beam, an output face aligned with an optical axis of the light beam prior to entering the input face, and three or more reflection faces. The three or more reflection faces may be oriented to provide an optical path for the light beam from the input face to the output face via reflection by the three or more reflection faces, where the monolithic optical retarder imparts a selected optical retardation on the light beam based on total internal reflection on at least one of the reflection faces. Further, the input face, the output face, and the three or more reflection faces may be oriented such that an optical axis of the light beam exiting the output face is equal to the optical axis of the light beam entering the input face.
-
公开(公告)号：US11231362B1
公开(公告)日：2022-01-25
申请号：US16723565
申请日：2019-12-20
Applicant: KLA Corporation
Inventor： Guorong V. Zhuang , Shankar Krishnan , David Y. Wang , Xuefeng Liu , Mengmeng Ye , Dawei Hu
IPC: G01N21/55 , G01N21/35 , G01N21/21 , G01N21/3563
Abstract: A system includes a light source, a Fourier transform infrared reflectometer (FTIR) spectrometer, and broadband reflectometer optics. The system is configured to measure polarized light and unpolarized reflectivities in a wavelength range from 2 μm to 20 μm. The light source can be a laser-driven light source. The spectroscopic reflectometer can include a single channel or two channels.
-
公开(公告)号：US11043239B2
公开(公告)日：2021-06-22
申请号：US16821192
申请日：2020-03-17
Applicant: KLA Corporation
Inventor： Jun Wang , Yaolei Zheng , Chunxia Li , Changfei Yan , Lansheng Dong , Yang Zhou , Hai-Yang You , Haijing Peng , Jianou Shi , Rui Ni , Shankar Krishnan , David Y. Wang , Walter H. Johnson
IPC: G11B11/105
Abstract: A laser beam is directed through a transmissive axicon telescope or a reflective axicon telescope such as in a magneto-optic Kerr effect metrology system. With the transmissive axicon telescope, a Gaussian beam profile is directed through a first axicon lens and a second axicon lens. The first axicon lens and second axicon lens transfer the Gaussian beam profile of the laser beam to a hollowed laser ring. The laser beam with a hollowed laser ring can be directed through a Schwarzschild reflective objective. With the reflective axicon telescope, the laser beam is directed through two conical mirrors that are fully reflective. One of the conical mirrors defines a central hole that the laser beam passes through.
-
公开(公告)号：US20200302965A1
公开(公告)日：2020-09-24
申请号：US16821192
申请日：2020-03-17
Applicant: KLA Corporation
Inventor： Jun Wang , Yaolei Zheng , Chunxia Li , Changfei Yan , Lansheng Dong , Yang Zhou , Hai-Yang You , Haijing Peng , Jianou Shi , Rui Ni , Shankar Krishnan , David Y. Wang , Walter H. Johnson , Barry Blasenheim
IPC: G11B11/105
Abstract: A laser beam is directed through a transmissive axicon telescope or a reflective axicon telescope such as in a magneto-optic Kerr effect metrology system. With the transmissive axicon telescope, a Gaussian beam profile is directed through a first axicon lens and a second axicon lens. The first axicon lens and second axicon lens transfer the Gaussian beam profile of the laser beam to a hollowed laser ring. The laser beam with a hollowed laser ring can be directed through a Schwarzschild reflective objective. With the reflective axicon telescope, the laser beam is directed through two conical mirrors that are fully reflective. One of the conical mirrors defines a central hole that the laser beam passes through.
-
公开(公告)号：US20250164411A1
公开(公告)日：2025-05-22
申请号：US18911630
申请日：2024-10-10
Applicant: KLA Corporation
Inventor： William McGahan , Shankar Krishnan
IPC: G01N21/95 , G01N23/20025
Abstract: Methods and systems for measuring structural parameters characterizing a measurement target based on changes in measurement signal values due to one or more perturbations of an effective illumination angle of incidence on the measurement target are presented herein. In some examples, a measurement model estimates values of the structural parameters based on the changes in measurement signal values. In some examples, at least one derivative of detected measurement signals with respect to effective illumination angle is determined, and values of the structural parameters are estimated based on the at least one derivative. In some examples, values of one or more tunable measurement model parameters are estimated based on at least one derivative. In some examples, the fitting performance of a measurement model is quantified based on measurements performed at both unperturbed and perturbed orientations of a structure under measurement with respect to the illumination beam.
-
20.发明公开
公开(公告)号：US20240201073A1
公开(公告)日：2024-06-20
申请号：US18231688
申请日：2023-08-08
Applicant: KLA Corporation
Inventor： Shankar Krishnan , Kaichun Yang , Xi Chen
IPC: G01N21/21 , G01N21/956 , G01N21/958
CPC classification number: G01N21/211 , G01N21/956 , G01N21/958 , G01N2021/213
Abstract: Methods and systems for performing spectroscopic ellipsometry (SE) measurements of surface structures of optical elements fabricated on transparent substrates are presented herein. The SE measurement system is configured to detect light from the measured structures without contamination from light reflected from the backside surface of the transparent substrate. Surface structures of optical elements include film structures and grating structures fabricated on thin transparent substrates. The SE based measurement system is configured with a relatively large illumination Numerical Aperture (NA) and relatively high demagnification from the illumination source to the measurement spot on the optically transparent substrate. This configuration results in a relatively small measurement spot size and small depth of focus that minimizes the amount of light reflected from the backside of the optically transparent substrate. In addition, a relatively small collection aperture size further minimizes backside reflected light from reaching the detector.
