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Proceedings Paper

Assessment of 5-pole illumination for 65nm-node contact holes
Author(s): Francois Weisbuch; Scott Warrick; Will Conley; Jerome Depre
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Paper Abstract

The greatest challenge for 65-nm contact holes and via printing is ensuring an acceptable process window (250-nm DoF @ 8% EL) for a wide range of pitches with a MEEF lower than 3.5. To print dense contact holes / vias with a CD less than 100-nm, very high Numerical Apertures (≥ 0.85) are required. Consequently DoF through pitch is dramatically reduced, such that it becomes absolutely necessary to develop new techniques to enhance process latitude. In this paper, we will study the use of customized illuminations formed by combination of small radius conventional illumination and quasar. Generically, this type of illumination is commonly referred to as 5-pole illumination. Specifically this paper, the “windmill” and “soft quasar” options are investigated. These designs are based upon the assumption, that there is a way to optimize for all pitches, the imaging lens pupil filling with diffracted orders. Using a combination of aerial image simulations and experimental (double) exposures, the optimal 5-pole illumination designs are derived, with their simulated performance being compared to conventional illumination settings. For the optimised designs, experimental data is presented for “real” device structures based on the Crolles2 65-nm technology design rules.

Paper Details

Date Published: 12 May 2005
PDF: 12 pages
Proc. SPIE 5754, Optical Microlithography XVIII, (12 May 2005); doi: 10.1117/12.599760
Show Author Affiliations
Francois Weisbuch, STMicroelectronics (France)
Scott Warrick, Freescale Semiconducteurs SAS (France)
Will Conley, Freescale Semiconductor, Inc. (United States)
Jerome Depre, ASML (France)

Published in SPIE Proceedings Vol. 5754:
Optical Microlithography XVIII
Bruce W. Smith, Editor(s)

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