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Proceedings Paper

Image-based overlay (IBO) target segment design on self-aligned patterning process
Author(s): Lei Ye; Huayong Hu; Weiming He
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Paper Abstract

Self-Aligned Double Patterning (SADP) is widely applied in advanced sub-4X patterning technology, especially for the 1D resolution shrinkage of memory technology. As the application of SADP makes lithography minimum pitch down to half of design pitch with the remaining spacer aside core, its alignment mark and overlay (OVL) mark have to be well-segmented to ensure enough mark contrast. In this paper, we designed two types of image-based overlay (IBO) bar in bar (BIB) OVL target: bar-segmentation and background–segmentation with different duty ratio. Based on these two designed types of marks, we focus on the OVL of 2nd photo layer to 1st SADP layer with the core removed (which means spacer grating structure remained). We studied the effect of the overlay target segmentation on the precision and robustness of wafer-level overlay performance. Different lithography processes were also studied, including single layer lithography and tri-layer lithography with planarized spacer grating structures. We found there are strong correlations between overlay measurement accuracy and background segmentation rules. The results of our study will be presented and discussed in this paper.

Paper Details

Date Published: 8 March 2016
PDF: 7 pages
Proc. SPIE 9778, Metrology, Inspection, and Process Control for Microlithography XXX, 977828 (8 March 2016); doi: 10.1117/12.2220017
Show Author Affiliations
Lei Ye, Semiconductor Manufacturing International Corp. (China)
Huayong Hu, Semiconductor Manufacturing International Corp. (China)
Weiming He, Semiconductor Manufacturing International Corp. (China)

Published in SPIE Proceedings Vol. 9778:
Metrology, Inspection, and Process Control for Microlithography XXX
Martha I. Sanchez, Editor(s)

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