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Proceedings Paper

Layout optimization for thick-film resist overlay metrology
Author(s): Liang Zhu; James Li; Brian Zhou; Yili Gu; Steve Yang
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Paper Abstract

Design for Manufacturing (DFM) is being widely accepted as one of the keywords in cutting edge lithography and OPC technologies. DFM solutions impact the design-to-silicon flow at various stages, often during different time-point in the product life cycle, and often with both process equipments and metrology tools. As the design rule shrinks and mask field size increases, tighter specifications are applied on non-critical layers, including thick implant resist typically with thickness of 3.0um and above. Various functions, as Enhanced Global Alignment (EGA), Super Distortion Matching (SDM), and Grid Compensation for Matching (GCM), are widely used to achieve improved overlay accuracy. However, poor uniformity for CD and overlay was observed for thick resist implant layers. Systematic uncorrectable overlay residue was observed from the overlay map. Cross-section analysis shows asymmetric resist profile existed, causing inaccurate signal reading during the measurement. Although there are some recent researches focusing on CD-SEM metrology of overlay residue, overlay tools in current foundries are mainly optical-based ones, which are limited by the optical resolution. Instead of locally focusing on the manufacturing, an innovative methodology is proposed in this paper, by applying the newly designed overlay marks to solve this manufacturing problem. From the comparison of overlay performances between the proposed layout and the original design, it is shown that the taper asymmetry induced errors are significantly reduced.

Paper Details

Date Published: 21 November 2007
PDF: 8 pages
Proc. SPIE 6827, Quantum Optics, Optical Data Storage, and Advanced Microlithography, 682726 (21 November 2007); doi: 10.1117/12.756182
Show Author Affiliations
Liang Zhu, Shanghai Institute of Microsystem And Information Technology (China)
Graduate School of Chinese Academy of Science (China)
Grace Semiconductor Manufacturing Corp. (China)
James Li, Grace Semiconductor Manufacturing Corp. (China)
Brian Zhou, Grace Semiconductor Manufacturing Corp. (China)
Yili Gu, Grace Semiconductor Manufacturing Corp. (China)
Steve Yang, Grace Semiconductor Manufacturing Corp. (China)

Published in SPIE Proceedings Vol. 6827:
Quantum Optics, Optical Data Storage, and Advanced Microlithography
Chris A. Mack; Guangcan Guo; Guofan Jin; Song-hao Liu; Kees A. Schouhamer Immink; Jinfeng Kang; Jun-en Yao; Keiji Shono; Osamu Hirota, Editor(s)

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