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Proceedings Paper

Near-0.3 k1 full pitch range contact hole patterning using chromeless phase lithography (CPL)
Author(s): Douglas J. Van Den Broeke; Robert Socha; Stephen D. Hsu; J. Fung Chen; Thomas L. Laidig; Noel Corcoran; Uwe Hollerbach; Kurt E. Wampler; Xuelong Shi
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Paper Abstract

Resolution Enhancement Techniques (RET), or low k1 imaging, has been deployed successfully to extend the resolution limits of optical lithography significantly below half-λ for today's poly gate mask in the state-of-the-art manufacturing processes. However, achieving satisfactory contact hole patterning through the full pitch range required for the 90nm and 65nm technology nodes has greatly challenged the leading process development effort. Currently, attenuated PSM's with transmission between 5% and 9% are used to enhance the resolution of dark field contact hole patterns. Using conventional illumination with a low sigma, which is the common method employed for att-PSM, limits the minimum pitch that can be resolved on the wafer. By using off-axis illumination (OAI) it is possible to image smaller pitches. However, the same attributes that enhance imaging for dense patterns severely degrade the imaging of isolated patterns. Using Chromeless Phase Lithography (CPL), sub-wavelength isolated contact patterns can be imaged using strong off-axis illumination, such as Quasar, dipole and double dipole, etc. By applying modeled sub-resolution and non-printing features, we found it is possible to achieve very high-resolution contact imaging with exceptional process latitude. Both phase shifted and non-phase shifted patterns can be much larger than sub-resolution assist features (or anti-Scattering Bars) used on dark field binary reticles (~three times larger), making the reticle pattern easier to manufacture. Using this method, sub-wavelength bright patterns on a dark field can be imaged through the full pitch range. We have shown that it is feasible to push the contact resolution limit to 0.33 k1 or smaller.

Paper Details

Date Published: 17 December 2003
PDF: 12 pages
Proc. SPIE 5256, 23rd Annual BACUS Symposium on Photomask Technology, (17 December 2003); doi: 10.1117/12.518308
Show Author Affiliations
Douglas J. Van Den Broeke, ASML MaskTools, Inc. (United States)
Robert Socha, ASML MaskTools, Inc. (United States)
Stephen D. Hsu, ASML MaskTools, Inc. (United States)
J. Fung Chen, ASML MaskTools, Inc. (United States)
Thomas L. Laidig, ASML MaskTools, Inc. (United States)
Noel Corcoran, ASML MaskTools, Inc. (United States)
Uwe Hollerbach, ASML MaskTools, Inc. (United States)
Kurt E. Wampler, ASML MaskTools, Inc. (United States)
Xuelong Shi, ASML MaskTools, Inc. (United States)

Published in SPIE Proceedings Vol. 5256:
23rd Annual BACUS Symposium on Photomask Technology
Kurt R. Kimmel; Wolfgang Staud, Editor(s)

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