Dr. Lewis Flanagin Profile

Dr. Lewis Flanagin

Design Engineer

SPIE Involvement:

Author

Area of Expertise:

photolithography , optical proximity correction , design for manufacturability , process development , resolution enhancement technology

Experienced chemical process engineer in research and advanced technology development. Extensive background in model formulation and computer simulation. Adept at technical writing and presentations. Manifested ability to interact with international business partners. Proven team leadership and effectiveness in training others. Demonstrated flexibility across engineering disciplines.

Proceedings Article | 17 March 2008 Paper

Inverse lithography as a DFM tool: accelerating design rule development with model-based assist feature placement, fast optical proximity correction and lithographic hotspot detection

Lewis Flanagin, Guangming Xiao, Sean O'Brien, Steve Prins, Thuc Dam, James Blatchford, Simon Chang, Bob Gleason, Timothy Lin, Scott Jessen

Proceedings Volume 6925, 69250E (2008) https://doi.org/10.1117/12.774581

KEYWORDS: Lithography, SRAF, Photomasks, Logic, Optical proximity correction, Lithographic illumination, Printing, Critical dimension metrology, Design for manufacturing, Model-based design

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Design rule (DR) development strategies were fairly straightforward at earlier technology nodes when node-on-node scaling could be accommodated easily by reduction of λ/NA. For more advanced nodes, resolution enhancement technologies such as off-axis illumination and sub-resolution assist features have become essential for achieving full shrink entitlement, and DR restrictions must be implemented to comprehend the inherent limitations of these techniques (e.g., forbidden pitches) and the complex and unanticipated 2D interactions that arise from having a large number of random geometric patterns within the optical ambit. To date, several factors have limited the extent to which 2D simulations could be used in the DR development cycle, including exceedingly poor cycle time for optimizing OPC and SRAF placement recipes per illumination condition, prohibitively long simulation time for characterizing the lithographic process window on large 2D layouts, and difficulty in detecting marginal lithographic sites using simulations based on discrete cut planes. We demonstrate the utility of the inverse lithography technology technique [1] to address these limitations in the novel context of restrictive DR development and design for manufacturability for the 32nm node. Using this technique, the theoretically optimum OPC and SRAF treatment for each layout are quickly and automatically generated for each candidate illumination condition, thereby eliminating the need for complex correction and placement recipes. "Ideal" masks are generated to explore physical limits and subsequently "Manhattanized" in accordance with mask rules to explore realistic process limits. Lithography process window calculations are distributed across multiple compute cores, enabling rapid full-chip-level simulation. Finally, pixel-based image evaluation enables hot-spot detection at arbitrary levels of resolution, unlike the 'cut line' approach. We have employed the ILT technique to explore forbidden-pitch contact hole printing in random logic. Simulations from cells placed in random context are used to evaluate the effectiveness of restricting pitches in contact hole design rules. We demonstrate how this simulation approach may not only accelerate the design rule development cycle, but also may enable more flexibility in design by revealing overly restrictive rules, or reduce the amount of hot-spot fixing required later in the design phase by revealing where restrictions are needed.

Proceedings Article | 14 March 2006 Paper

Accurate OPC model generation through use of a streamlined data flow incorporating automated test-structure layout and CD-SEM recipe generation

Lewis Flanagin, James Blatchford, Steve Prins, Ben Rathsack, Mary Coles

Proceedings Volume 6156, 615614 (2006) https://doi.org/10.1117/12.660600

KEYWORDS: Data modeling, Optical proximity correction, Scanning electron microscopy, SRAF, Semiconducting wafers, Photomasks, Image filtering, Process modeling, Error analysis, Data processing

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Proceedings Article | 24 August 2001 Paper

Understanding nonlinear dissolution rates in photoresists

Paula Wetmore, Sean Burns, Lewis Flanagin, Jodie Lutkenhaus, Gerard Schmid, Val Krukonis, C. Grant Willson, Allen Gardiner

Proceedings Volume 4345, (2001) https://doi.org/10.1117/12.436876

KEYWORDS: Polymers, Oxygen, Surface roughness, Picture Archiving and Communication System, Medium wave, Polymer thin films, Photoresist materials, Ionization, FT-IR spectroscopy, Oxidation

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Proceedings Article | 23 June 2000 Paper

Recent advances in a molecular level lithography simulation

Sean Burns, C. Grant Willson, Lewis Flanagin, Michael Stewart, Vivek Singh, Gerard Schmid

Proceedings Volume 3999, (2000) https://doi.org/10.1117/12.388354

KEYWORDS: Polymers, Computer simulations, Molecules, Diffusion, Lithography, Monte Carlo methods, Photoresist materials, Performance modeling, Deep ultraviolet, Polymer thin films

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Proceedings Article | 29 June 1998 Paper

Dissolution of phenolic polymers in aqueous base: the influence of polymer structure

Christopher McAdams, Adam Pawlowski, Clifford Henderson, C. Grant Willson, Lewis Flanagin, Pavlos Tsiartas

Proceedings Volume 3333, (1998) https://doi.org/10.1117/12.312345

KEYWORDS: Polymers, Ionization, Hydrogen, Photoresist materials, Diffusion, Deep ultraviolet, Chromophores, Photoresist developing, Polarization, Ions

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Proceedings Article | 29 June 1998 Paper

Probabilistic model for the mechanism of phenolic polymer dissolution

Clifford Henderson, C. Grant Willson, Christopher McAdams, William Hinsberg, Lewis Flanagin, Pavlos Tsiartas

Proceedings Volume 3333, (1998) https://doi.org/10.1117/12.312416

KEYWORDS: Polymers, Polymerization, Ionization, Photoresist materials, Data modeling, Diffusion, Polymer thin films, Photoresist developing, Etching, Polymethylmethacrylate

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Proceedings Article | 7 July 1997 Paper

Photoresist characterization for lithography simulation: IV. Processing effects on resist parameters

Lewis Flanagin, Ammar Chinwalla, C. Grant Willson, Sajed Chowdhury, Sanju Pancholi, Clifford Henderson, Pavlos Tsiartas, Katherine Dombrowski

Proceedings Volume 3049, (1997) https://doi.org/10.1117/12.275820

KEYWORDS: Photoresist developing, Semiconducting wafers, Photoresist materials, Lithography, Picture Archiving and Communication System, Refractive index, Absorption, Photoresist processing, Statistical analysis, Data modeling

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