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22 March 2011 Improving double patterning flow by analyzing the diffractive orders in the pupil plane
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To print sub 22nm node features, current lithography technology faces some tool limitations. One possible solution to overcome these problems is to use the double patterning technique (DPT). The principle of the double patterning technique is pitch splitting where two adjacent features must be assigned opposite masks (colors) corresponding to different exposures if their pitch is less than a predefined minimum coloring pitch. However, certain design orientations for which pattern features separated by more than the minimum coloring pitch cannot be imaged with either of the two exposures. In these directions, the contrast and the process window are degraded because constructive interferences between diffractive orders in the pupil plane are not sufficient. The 22nm and 16nm nodes require the use of very coherent sources that will be generated using SMO (source mask cooptimization). Such pixelized sources while helpful in improving the contrast for selected configurations, can lead to degrade it for configurations which have not been counted for during the SMO process. Therefore, we analyze the diffractive orders interactions in the pupil plane in order to detect these limited orientations in the design and thus propose a new double patterning decomposition algorithm to enlarge the process window and the contrast of each mask.
© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
N. Zeggaoui, V. Farys, M. Besacier, Q. Li, E. Yesilada, and Y. Trouiller "Improving double patterning flow by analyzing the diffractive orders in the pupil plane", Proc. SPIE 7973, Optical Microlithography XXIV, 79730M (22 March 2011);

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