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Proceedings Paper

CD prediction by threshold energy resist model (TERM)
Author(s): Ji-Yong Yoo; Yeong-Keun Kwon; Jun-Taek Park; Dong-Soo Sohn; Sang-Gon Kim; Young-Soo Sohn; Hye-Keun Oh
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Paper Abstract

In the step of developing lithography devices, VTRM (Variable Threshold Resist Model), aerial image based simulation, is useful to get feedback for a resist process margin. VTRM is also used to compensate for the mask pattern's OPE (Optical Proximity Effect) and to optimize the optical system rather than the full simulation method that requires all the process parameters. However, VTRM has shown some problems that the exposure dose and focus should be fixed in one special condition to improve the prediction accuracy and cannot be combined together in one equation for pattern's size and type variation. In this paper, a new simulation method that has more accuracy and wider applicability than the VTRM method was suggested. The new simulation method can represent the photolithography process with simple formula. The parameters of this formula are composed of exposure dose and defocus as input components, CD as output component, and all the resist processes are kept constant to keep consistency for other resist processes. The first technical improvement of this equation is to use process-matched aerial image derived from the fact that the aerial images at the top resist surface cannot represent the bulk resist energy distribution. The second one is to introduce a new concept TERM (Threshold Energy Resist Model). The energy threshold level is used instead of the aerial image's intensity threshold level in order to predict CDs. Energy threshold level can be simply found by the simple equation and an experiment. The simple equation consists of a mask edge opening energy, the mask edge image intensity, and a process factor.

Paper Details

Date Published: 30 July 2002
PDF: 9 pages
Proc. SPIE 4691, Optical Microlithography XV, (30 July 2002); doi: 10.1117/12.474510
Show Author Affiliations
Ji-Yong Yoo, Hanyang Univ. (South Korea)
Yeong-Keun Kwon, Hanyang Univ. (South Korea)
Jun-Taek Park, Hanyang Univ. (South Korea)
Dong-Soo Sohn, Hanyang Univ. (South Korea)
Sang-Gon Kim, Hanyang Univ. (South Korea)
Young-Soo Sohn, Hanyang Univ. (South Korea)
Hye-Keun Oh, Hanyang Univ. (South Korea)

Published in SPIE Proceedings Vol. 4691:
Optical Microlithography XV
Anthony Yen, Editor(s)

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