Dr. Meghali C. Chopra Profile

Dr. Meghali C. Chopra

CEO at SandBox Semiconductor

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Author

Publications (17)

Proceedings Article | 1 May 2023 Presentation + Paper

A method for achieving sub-2nm across-wafer uniformity performance

Meghali Chopra, Leandro Medina, Yang Ban, Michael Da Silva, Sebastian Naranjo

Proceedings Volume 12499, 1249907 (2023) https://doi.org/10.1117/12.2662423

KEYWORDS: Semiconducting wafers, Metrology, Image segmentation, 3D modeling, Etching, Critical dimension metrology, Artificial intelligence, 3D metrology, Scanning electron microscopy, Image processing

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Reducing process development time and speeding up time to market are perennial challenges in the microelectronics industry. The development of etch models that permit optimizations across the wafer would enable manufacturers to optimize process design flows and predict process defects before a single wafer is run. The challenges of across-wafer uniformity optimizations include the large variety of features across the wafer, etch variations that occur at multiple scales within the plasma chamber, feature metrology, and computationally expensive model development. Compounding these challenges are trade-offs between data quality and time/cost-effectiveness, the wide variety of measurement information provided by different tools, and the sparsity and inconsistency of human-collected data. We address these challenges with a feature and wafer level modeling approach. First, experiments are conducted for a variety of etch conditions (e.g., pressure, gas composition, flow rate, temperature, power, and bias). Second, a feature level model is calibrated at multiple sites across the wafer based on OCD and/or cross-sectional SEM measurements. Finally, the calibrated model is used to predict an optimal set of process conditions to preserve uniformity across the wafer and to meet recipe targets. We demonstrate the methodology using SandBox Studio™ AI for a FinFET application. Specifically, we show the rapid and automated calibration of feature level models using experimental measurements of the 3D feature etch at a variety of process conditions. Automated image segmentation of X-SEM data is also performed here for single case using Weave^® to demonstrate how such data can be acquired quickly in a development environment. We then demonstrate the effectiveness of the reduced-order model to predict optimal recipe conditions to improve overall recipe performance. We show how, with this hybrid-metrology computational approach, a process window that yields 89.2% of the wafer can be captured.

Proceedings Article | 26 May 2022 Poster + Paper

Automated extraction of critical dimension from SEM with Weave

Meghali Chopra, Bryan Sundahl, Yang Ban, Roger Bonnecaze, Jawad Ahmed, Crystal Barrera, S.V. Sreenivasan

Proceedings Volume 12053, 1205327 (2022) https://doi.org/10.1117/12.2614282

KEYWORDS: Scanning electron microscopy, Image segmentation, Artificial intelligence, Image processing, Process engineering, Image analysis, Wet etching, Semiconductors, Neural networks, Metals

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Proceedings Article | 25 May 2022 Poster + Paper

Creating new multistep etch and deposition processes with recycled etch data using SandBox Studio AI

Meghali Chopra, Kara Kearney, Leandro Medina, Roger Bonnecaze

Proceedings Volume 12056, 120560E (2022) https://doi.org/10.1117/12.2614301

KEYWORDS: Etching, Calibration, Data modeling, Surface roughness, Process modeling, Photomasks, Extreme ultraviolet, Artificial intelligence, Deposition processes, Optimization (mathematics)

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Proceedings Article | 25 May 2022 Presentation + Paper

Automated, high throughput optimization of multistep and cyclic etch and deposition processes using SandBox Studio AI

Meghali Chopra, Roger Bonnecaze, Kara Kearney, Leandro Medina

Proceedings Volume 12056, 1205608 (2022) https://doi.org/10.1117/12.2614284

KEYWORDS: Etching, Calibration, Artificial intelligence, Data modeling, Deposition processes, Physics, Machine learning, Optimization (mathematics), Semiconductors, Tolerancing

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Proceedings Article | 22 February 2021 Presentation + Paper

Fast etch recipe creation with automated model-based process optimization

Roger Bonnecaze, Meghali Chopra, Leandro Medina, Bryan Sundahl, Yang Ban, Kara Kearney

Proceedings Volume 11615, 116150L (2021) https://doi.org/10.1117/12.2583868

KEYWORDS: Process modeling, Etching, Optimization (mathematics), Model-based design, 3D modeling, Calibration, Statistical modeling, Statistical analysis, Space mirrors, Process engineering

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Proceedings Article | 22 February 2021 Poster + Presentation + Paper

Automated extraction of critical dimension from SEM images with WeaveTM

Roger Bonnecaze, Meghali Chopra, Leandro Medina, Bryan Sundahl

Proceedings Volume 11611, 1161135 (2021) https://doi.org/10.1117/12.2583900

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Proceedings Article | 25 March 2020 Paper

Accelerated optimization of multilayer trench etches using model-based experimental design

Roger Bonnecaze, Xilan Zhu, Sonali Chopra, Yang Ban, Meghali Chopra, Kara Kearney

Proceedings Volume 11329, 113290Z (2020) https://doi.org/10.1117/12.2552156

KEYWORDS: Etching, System on a chip, Silicon, Calibration, Model-based design, Argon, Optimization (mathematics), Critical dimension metrology, Semiconductors, Plasma etching

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Proceedings Article | 23 March 2020 Presentation + Paper

Optimal etch recipe prediction for 3D NAND structures

Roger Bonnecaze, Meghali Chopra, Leandro Medina, Bryan Sundahl

Proceedings Volume 11329, 113290C (2020) https://doi.org/10.1117/12.2552121

KEYWORDS: Etching, Calibration, 3D modeling, Process modeling, Solid modeling, Silicon, Model-based design, Data modeling, 3D acquisition, Visual process modeling

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Proceedings Article | 20 March 2019 Presentation + Paper

Simulation and optimization of etch on flexible substrates for roll-to-roll processing

Roger Bonnecaze, Meghali Chopra, Sofia Helpert, Yang Ban

Proceedings Volume 10963, 109630T (2019) https://doi.org/10.1117/12.2515104

KEYWORDS: Etching, Calibration, Plasma etching, Amorphous silicon, Plasma, Manufacturing, Reactive ion etching, Analytics, Data modeling

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Proceedings Article | 20 March 2019 Presentation + Paper

Predicting and optimizing etch recipes for across the wafer uniformity

Roger Bonnecaze, Meghali Chopra, Yang Ban, Sofia Helpert

Proceedings Volume 10963, 1096309 (2019) https://doi.org/10.1117/12.2515097

KEYWORDS: Semiconducting wafers, Etching, Neural networks, Calibration, Process modeling, Cadmium sulfide, Critical dimension metrology, Plasma, Plasma etching, Data modeling

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Proceedings Article | 20 March 2018 Presentation + Paper

A cellular automata simulation of atomic layer etching

Roger Bonnecaze, Meghali Chopra, Jan Strotmann

Proceedings Volume 10589, 105890H (2018) https://doi.org/10.1117/12.2297435

KEYWORDS: Etching, Chemical species, Focus stacking software, Silicon, Argon, Chlorine, Plasma, Ions, Surface roughness

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Proceedings Article | 20 March 2018 Presentation + Paper

A model-based, Bayesian approach to the CF4/Ar etch of SiO2

Meghali Chopra, Xilan Zhu, Zizhuo Zhang, Sofia Helpert, Rahul Verma, Roger Bonnecaze

Proceedings Volume 10588, 105880G (2018) https://doi.org/10.1117/12.2297482

KEYWORDS: Etching, Plasma, Autoregressive models, Systems modeling, Calibration, Argon, Data modeling, Ions, Model-based design, Chemistry

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Proceedings Article | 20 March 2018 Presentation + Paper

Minimum reaction network necessary to describe Ar/CF4 plasma etch

Meghali Chopra, Roger Bonnecaze, Sofia Helpert

Proceedings Volume 10589, 105890J (2018) https://doi.org/10.1117/12.2297502

KEYWORDS: Plasma, Autoregressive models, Plasma etching, Databases, Argon, Etching, Data modeling, Plasma systems, Temperature metrology, Particles

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Proceedings Article | 21 March 2017 Paper

A method to accelerate creation of plasma etch recipes using physics and Bayesian statistics

Meghali Chopra, Roger Bonnecaze, Rahul Verma, Austin Lane, C. Willson

Proceedings Volume 10149, 101490X (2017) https://doi.org/10.1117/12.2263507

KEYWORDS: Plasma, Plasma etching, Etching, Data modeling, Calibration, Physics, Chemistry, Parallel computing, Semiconducting wafers, Sputter deposition, Diffractive optical elements, Anisotropy, Plasma systems, Process engineering, Ions

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Proceedings Article | 16 March 2016 Paper

Rapid recipe formulation for plasma etching of new materials

Meghali Chopra, Zizhuo Zhang, John Ekerdt, Roger Bonnecaze

Proceedings Volume 9781, 978111 (2016) https://doi.org/10.1117/12.2219171

KEYWORDS: Etching, Plasma, Data modeling, Plasma etching, Dry etching, Magnesium, Oxides, Chemistry, Optimization (mathematics), Bayesian inference, Calibration, Ions, Autoregressive models, Electrons, Statistical modeling

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SPIE Journal Paper | 21 October 2015

Impact of polymer curing on two-dimensional and three-dimensional shape change in nanoimprint lithography

Meghali Chopra, Roger Bonnecaze

JM3, Vol. 14, Issue 04, 044502, (October 2015) https://doi.org/10.1117/12.10.1117/1.JMM.14.4.044502

KEYWORDS: Etching, Polymers, Diamond, Nanoimprint lithography, Distortion, Anisotropic etching, Oxides, Image processing, 3D modeling, 3D image processing

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Proceedings Article | 15 April 2015 Paper

Shape change of cured 2D and 3D nanostructures from imprint lithography

Meghali Chopra, Roger Bonnecaze

Proceedings Volume 9423, 94230W (2015) https://doi.org/10.1117/12.2186050

KEYWORDS: Polymers, Nanoimprint lithography, 3D modeling, Nanostructures, Lithography, Ultraviolet radiation, Diamond, Image processing, Manufacturing, Finite element methods

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Showing 5 of 17 publications

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