
Proceedings Paper
Roadmap to sub-nanometer OPC model accuracyFormat | Member Price | Non-Member Price |
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Paper Abstract
OPC models describe the entire patterning process, including photomask, optics, resist, and etch as a set of
separately characterized modules. It is difficult, however, to definitively calibrate the optics model since the aerial
image is not easily measurable. It is therefore common to calibrate relevant optical parameters using a constant
threshold applied to the aerial image in order to best fit the experimentally measured photoresist CDs. With the
optical model thus fixed, a subsequent tuning of resist model parameters is enabled. Alternatively, both optical and
resist parameters can be tuned in a single lumped calibration to the measurement data. The parameters associated
with the calibration of the photomask, optical, resist and etch processes can be sorted into three classes. There are
parameters that are directly measurable or known as designed-in values, such as wavelength, numerical aperture
(NA), illumination source profile, and film stack optical constants. A second class of parameters is associated with
physical phenomena, where direct measurement is not done, but rather the model contains mathematical proxies for
the parameters. A final class of calibration options includes software options for altering the approximations used in
the model, such as number of optical kernels, optical diameter, and the functional form of the resist or etch model.
The degree to which the model can faithfully decouple photomask from optical exposure from resist processing is
related not only to the details of the resist model, but also to the nature of the approximations "upstream" in the
representation of the mask and optical system. This paper will systematically explore the impact of all components
in the photomask and optical models, and will provide a pathway to sub-nanometer accuracy required for 20 nm
technology.
Paper Details
Date Published: 29 June 2012
PDF: 12 pages
Proc. SPIE 8441, Photomask and Next-Generation Lithography Mask Technology XIX, 84410H (29 June 2012); doi: 10.1117/12.978190
Published in SPIE Proceedings Vol. 8441:
Photomask and Next-Generation Lithography Mask Technology XIX
Kokoro Kato, Editor(s)
PDF: 12 pages
Proc. SPIE 8441, Photomask and Next-Generation Lithography Mask Technology XIX, 84410H (29 June 2012); doi: 10.1117/12.978190
Show Author Affiliations
John L. Sturtevant, Mentor Graphics Corp. (United States)
Edita Tejnil, Mentor Graphics Corp. (United States)
Published in SPIE Proceedings Vol. 8441:
Photomask and Next-Generation Lithography Mask Technology XIX
Kokoro Kato, Editor(s)
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