Automated S/TEM metrology on advanced semiconductor gate structures

Strauss, M.; Arjavac, Jason; Horspool, D. N.; Nakahara, Ken; Deeb, Chris; Hobbs, Chris

doi:10.1117/12.916526

Cited by 8 publications

(5 citation statements)

References 2 publications

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“…In this study, the magnification variation was evaluated using the (220) lattice spacing of crystalline Si. Because ( 220) and (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) are orthogonal and equivalent planes, no difference should be seen between their lattice spacings. However, there may be a slight difference between the lattice spacings of ( 220) and (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) in TEM images due to distortion of pixels in the CCD camera and/or residual astigmatism of the objective lens.…”

Section: Intermediate Precisionmentioning

confidence: 99%

“…Because ( 220) and (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) are orthogonal and equivalent planes, no difference should be seen between their lattice spacings. However, there may be a slight difference between the lattice spacings of ( 220) and (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) in TEM images due to distortion of pixels in the CCD camera and/or residual astigmatism of the objective lens. We evaluated the ∆10d 220 values due to 90 • rotation of the TEM image by comparing the measured values of 10d 220 obtained from the TEM images acquired to evaluate the intraday repeatability involving nonuniformity of the specimen structure and from the corresponding images after clockwise-rotation by 90 • .…”

Section: Intermediate Precisionmentioning

confidence: 99%

“…These studies have provided a strategy for measuring the CDs of reference materials consisting of Si single crystals by calibrating the magnification of the TEM images using the lattice spacing of Si as an internal reference (direct image calibration [3]). Moreover, automated CD-TEM and CD-STEM (CD-S/TEM) techniques in which the Si lattice spacing is used as an internal reference for magnification calibration have emerged as a practical approach for measuring the CDs of Si-based semiconductors in industrial metrology [1,13,14]. However, these previous studies and CD-S/TEM are not readily applicable to metrology of ultrafine structures on the subnanometer scale.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Experimental evaluation of uncertainty in sub-nanometer metrology using transmission electron microscopy due to magnification variation

Kobayashi

Misumi

Yamamoto

2021

Meas. Sci. Technol.

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Uncertainties due to the magnification variation in sub-nanometer metrology using transmission electron microscopy (TEM) were experimentally evaluated by comparing the measured values of the (220) lattice spacing of a crystalline Si specimen acquired under various conditions. Interday variation of the magnification, intraday repeatability, rotation of the TEM image, specimen exchange, specimen position, defocusing, magnetic hysteresis of the lenses, projection lens distortion, and measurement errors were considered as the uncertainty components. The obtained results reveal that the major uncertainty components are the interday magnification variation, intraday repeatability involving nonuniformity of the specimen structure, magnetic hysteresis of the intermediate lenses, and projection lens distortion. Among these components, it is expected to be feasible to suppress the interday magnification variation to a negligible level by daily magnification calibration, suggesting that minimizing the uncertainties due to magnetic hysteresis of the intermediate lenses, projection lens distortion, and nonuniformity of the specimen structure will be the key factor for further reducing the uncertainty of sub-nanometer metrology using TEM. Furthermore, we found that magnification calibration using an appropriate reference material (e.g. the lattice fringes of crystalline Si) before every measurement should enables sub-nanometer metrology with a relative uncertainty of 3.2%, even if the specimen is introduced into the TEM system by specimen exchange after magnification calibration.

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Section: Intermediate Precisionmentioning

confidence: 99%

Section: Intermediate Precisionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Experimental evaluation of uncertainty in sub-nanometer metrology using transmission electron microscopy due to magnification variation

Kobayashi

Misumi

Yamamoto

2021

Meas. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…In this study, we present an automated TEM metrology and EDS characterization workflow for plan view DRAM capacitors. [9][10][11][12] We utilized a new X-ray Energy-Dispersive Spectroscopy (EDS) detector namely Ultra-X detector for elemental analysis. The Ultra-X detector provides high collection efficiency, enhancing throughput and accuracy in EDS metrology characterization.…”

Section: Introductionmentioning

confidence: 99%

Automated TEM metrology and EDS characterization of plan view DRAM capacitors

Gnanasekaran,

Strauss,

Zhou

et al. 2024

Metrology, Inspection, and Process Control XXXVIII

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Capacitors play an essential role in dynamic random-access memory (DRAM) devices. With continuous DRAM device scaling, critical dimension measurements and elemental analysis of capacitor structures becomes more critical. Here, we present an automated TEM metrology and EDS characterization workflow for plan view DRAM capacitors. We utilized a Metrios 6 (Scanning) Transmission Electron Microscope ((S)TEM) equipped with an Ultra-X Energy Dispersive X-Ray Spectroscopy (EDS) detector to obtain high-quality analytical information of DRAM capacitors. The large solid angle of the Ultra-X detector provides approximately 3-4 times more X-ray counts than the previous generation Dual-X detector. Further, we show Ultra-X detector can characterize the elemental composition even on layers as thin as ~1 nm using low electron doses. Additionally, we demonstrate that the extended EDS acquisition induces elemental diffusion and structural alterations, leading to a ~4% reduction in the radius of certain DRAM layers. These findings underscore the importance of controlling the electron dose during imaging to ensure accurate, reliable, and reproducible CD measurements.

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“…In this study, we present (S)TEM metrology characterization [5][6][7][8][9] using an automated Thermo Scientific TM Metrios TM (S)TEM on two typical process challenges. We introduce an internal machine learning-based modeling algorithm to address the challenge of measuring GAA structures with sacrificial SiGe etch process variations using a forksheet device.…”

Section: Introductionmentioning

confidence: 99%

Automated (S)TEM metrology characterization of gate-all-around and 3D NAND devices

Strauss

Hakala

et al. 2023

Metrology, Inspection, and Process Control XXXVII

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Fab and defect inspection workflows have reached an inflection point with the introduction of (GAA) and high aspect ratio memory structures. Few existing inspection and metrology tools can match the sub-surface imaging and analytical capability provided by (Scanning) Transmission Electron Microscopy (). Fully automated (S)TEM workflows are becoming a necessity for the industry to deliver high volume metrology reference data. This atomic scale data must be available with fast turnaround and must also be statistically valid to speed up learning cycles. In this study, we present (S)TEM metrology characterization of advanced GAA and devices by an automated MetriosTM TEM. We introduce an internal -based modeling algorithm to address the challenges of recognizing GAA devices with process variations and provide faster access to highly accurate TEM reference metrology data. We present automated characterization of beam-sensitive ONO layers, which is a key challenge in 3D NAND device metrology, enabled by a new generation of EDS detector with a high collection efficiency. We also present results on (S)TEM metrology during process monitoring of GAA devices with a higher level of TEM .

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Automated S/TEM metrology on advanced semiconductor gate structures

Cited by 8 publications

References 2 publications

Experimental evaluation of uncertainty in sub-nanometer metrology using transmission electron microscopy due to magnification variation

Experimental evaluation of uncertainty in sub-nanometer metrology using transmission electron microscopy due to magnification variation

Automated TEM metrology and EDS characterization of plan view DRAM capacitors

Automated (S)TEM metrology characterization of gate-all-around and 3D NAND devices

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