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Proceedings Paper

Fast and accurate laser bandwidth modeling of optical proximity effects
Author(s): Ivan Lalovic; Oleg Kritsun; Joeseph Bendik; Mark Smith; Chris Sallee; Nigel Farrar
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Paper Abstract

In this work, we model the effects of excimer laser bandwidth on optical proximity effects in high-NA ArF dry and immersion lithography. We quantify the errors introduced by using common approximation methods for the laser spectrum, such as the modified Lorentzian and Gaussian forms. Although these approximations are simple to use, and their symmetry properties can lead to reduced simulation run-times, they typically induce significant CD error when compared to the use of measured spectral profiles, which are obtained from high-resolution spectrophotometry. In this paper we establish some accuracy benchmarks and demonstrate the need for inclusion of information about the spectral profile - for the laser type of interest - in order to achieve sub-nanometer image calculation accuracy required for optical proximity correction. We further assess the speed-accuracy tradeoffs in terms of data truncation and sampling, and propose some practical limits for sampling the illumination spectrum. Additionally, in this work, we propose a new physically-based spectrum approximation method, which significantly reduces computation time at a cost of less than 0.25nm residual image-CD error from the fully-sampled image calculation. In addition to aerial image, we compare 45nm-node calibrated resist models and latent image results for 0.92NA dry and 1.2NA immersion processes using measured illumination profiles and lens aberrations. Finally, we consider the laser bandwidth sensitivity of 2D line-end patterns and typical post-OPC designs for a logic gate-process.

Paper Details

Date Published: 30 October 2007
PDF: 14 pages
Proc. SPIE 6730, Photomask Technology 2007, 67301X (30 October 2007); doi: 10.1117/12.746594
Show Author Affiliations
Ivan Lalovic, Cymer, Inc. (United States)
Oleg Kritsun, Advanced Micro Devices (United States)
Joeseph Bendik, Dynamic Intelligence Inc. (United States)
Mark Smith, KLA-Tencor Corp. (United States)
Chris Sallee, KLA-Tencor Corp. (United States)
Nigel Farrar, Cymer, Inc. (United States)

Published in SPIE Proceedings Vol. 6730:
Photomask Technology 2007
Robert J. Naber; Hiroichi Kawahira, Editor(s)

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