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Proceedings Paper

The impact of 14-nm photomask uncertainties on computational lithography solutions
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Paper Abstract

Computational lithography solutions rely upon accurate process models to faithfully represent the imaging system output for a defined set of process and design inputs. These models, which must balance accuracy demands with simulation runtime boundary conditions, rely upon the accurate representation of multiple parameters associated with the scanner and the photomask. While certain system input variables, such as scanner numerical aperture, can be empirically tuned to wafer CD data over a small range around the presumed set point, it can be dangerous to do so since CD errors can alias across multiple input variables. Therefore, many input variables for simulation are based upon designed or recipe-requested values or independent measurements. It is known, however, that certain measurement methodologies, while precise, can have significant inaccuracies. Additionally, there are known errors associated with the representation of certain system parameters. With shrinking total CD control budgets, appropriate accounting for all sources of error becomes more important, and the cumulative consequence of input errors to the computational lithography model can become significant. In this work, we examine with a simulation sensitivity study, the impact of errors in the representation of photomask properties including CD bias, corner rounding, refractive index, thickness, and sidewall angle. The factors that are most critical to be accurately represented in the model are cataloged. CD Bias values are based on state of the art mask manufacturing data and other variables changes are speculated, highlighting the need for improved metrology and awareness.

Paper Details

Date Published: 12 April 2013
PDF: 11 pages
Proc. SPIE 8683, Optical Microlithography XXVI, 868307 (12 April 2013); doi: 10.1117/12.2013748
Show Author Affiliations
John Sturtevant, Mentor Graphics Corp. (United States)
Edita Tejnil, Mentor Graphics Corp. (United States)
Tim Lin, Mentor Graphics Corp. (United States)
Steffen Schultze, Mentor Graphics Corp. (United States)
Peter Buck, Toppan Photomasks, Inc. (United States)
Franklin Kalk, Toppan Photomasks, Inc. (United States)
Kent Nakagawa, Toppan Photomasks, Inc. (United States)
Guoxiang Ning, GLOBALFOUNDRIES Inc. (United States)
Paul Ackmann, GLOBALFOUNDRIES Inc. (United States)
Fritz Gans, Advanced Mask Technology Ctr. (Germany)
Christian Buergel, Advanced Mask Technology Ctr. (Germany)


Published in SPIE Proceedings Vol. 8683:
Optical Microlithography XXVI
Will Conley, Editor(s)

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