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Proceedings Paper

Hyper NA polarized imaging of 45nm DRAM
Author(s): Chang-Moon Lim; Sarohan Park; Yoon-Suk Hyun; Jin-Soo Kim; Tae-Seung Eom; Jun-Taek Park; Seung-Chan Moon; Jin-Woong Kim
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Paper Abstract

In this paper, we will present experimental results on 45nm node patterning of DRAM and some technical issues for polarized illumination in hyper NA imaging. First, practical k1 limit of 1.2NA ArF immersion system is investigated through experiment. Process window and mask error enhancement factors are measured with respect to various design rules, i.e., different k1 levels at fixed NA. Reasonable process window and MEEF value of around 3 are achieved in DRAM gate and isolation layers at around 0.28 k1 regime. It is obvious that feasibility of this lowered k1 was realized by the help of polarized illumination when we compared the results with that of 60nm patterning at 0.93NA tool - corresponding k1 is 0.29 - without polarized illumination. Then consideration about degree of polarization state must come next to the benefit of polarized illumination. Input polarization state is changed by birefringence of lens or mask materials but it is very difficult to correlate the birefringence level and critical dimension of patterns experimentally. Double exposing method was contrived to measure the effect of degree of polarization on DICD. And we also measure the polarization dependent transmittance of light on mask by using 1.2NA immersion scanner. As a result, birefringence and mask feature interaction with light seems not to be a serious issue for 45nm hyper NA polarized imaging.

Paper Details

Date Published: 26 March 2007
PDF: 8 pages
Proc. SPIE 6520, Optical Microlithography XX, 65200B (26 March 2007); doi: 10.1117/12.712442
Show Author Affiliations
Chang-Moon Lim, Hynix Semiconductor Inc. (South Korea)
Sarohan Park, Hynix Semiconductor Inc. (South Korea)
Yoon-Suk Hyun, Hynix Semiconductor Inc. (South Korea)
Jin-Soo Kim, Hynix Semiconductor Inc. (South Korea)
Tae-Seung Eom, Hynix Semiconductor Inc. (South Korea)
Jun-Taek Park, Hynix Semiconductor Inc. (South Korea)
Seung-Chan Moon, Hynix Semiconductor Inc. (South Korea)
Jin-Woong Kim, Hynix Semiconductor Inc. (South Korea)

Published in SPIE Proceedings Vol. 6520:
Optical Microlithography XX
Donis G. Flagello, Editor(s)

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