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Proceedings Paper

Enabling virtual wafer CD (WCD) using inverse pattern rendering (IPR) of mask CD-SEM images
Author(s): Thuc Dam; Dongxue Chen; Hsien-Min Chang; Noel Corcoran; Paul Yu; Linyong Pang; Chia-Wei Chang; Rick Lai; Peter Chang; Laurent Tuo
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Paper Abstract

A wafer's printed CD error can be impacted by unaccounted mask making process variation. Unaccounted mask CD and/or corner rounding alters the intended drawn mask pattern contributing to a wafer's printed CD error. During OPC wafer calibration, average mask bias and corner rounding are accounted for in the OPC model, but random local mask making process variations or mask-to-mask variations can be difficult to account in such model calibration. Thus when a wafer's CD has error, it can be difficult to determine if the general root cause was due to mask or wafer or both. An in-line monitoring application has been developed to extract accurate mask CD and rendered mask polygon from collected mask CD-SEM images. Technical information will be presented on the challenges of accurately extracting information from SEM images. In particular, discussions include SEM image calibration, contour extraction, inverse pattern rendering, and general image processing to account for mask SEM aberrations (translation, rotation, & dilation), tool-to-tool variation, vendor-to-vendor variation, run-to-run variation, and dark/bright field pattern-to-pattern variation. After accurate mask SEM contours are obtained, lithographic simulations are performed on extracted polygon contours to determine the impact of mask variation on wafer CD. This paper will present detail information about the Inverse Pattern Rendering (IPR) capabilities developed for a virtual Wafer CD (WCD) application and its results, which is proven to achieved 0.5 nm accuracy across multiple critical layers from 28 nm to 40 nm nodes on multiple CD-SEM tools over multiple mask shop locations.

Paper Details

Date Published: 13 October 2011
PDF: 14 pages
Proc. SPIE 8166, Photomask Technology 2011, 81660O (13 October 2011); doi: 10.1117/12.896951
Show Author Affiliations
Thuc Dam, Luminescent Technologies, Inc. (United States)
Dongxue Chen, Luminescent Technologies, Inc. (United States)
Hsien-Min Chang, Luminescent Technologies, Inc. (United States)
Noel Corcoran, Luminescent Technologies, Inc. (United States)
Paul Yu, Luminescent Technologies, Inc. (United States)
Linyong Pang, Luminescent Technologies, Inc. (United States)
Chia-Wei Chang, Taiwan Semiconductor Manufacturing Co. Ltd. (Taiwan)
Rick Lai, Taiwan Semiconductor Manufacturing Co. Ltd. (Taiwan)
Peter Chang, Taiwan Semiconductor Manufacturing Co. Ltd. (Taiwan)
Laurent Tuo, Taiwan Semiconductor Manufacturing Co. Ltd. (Taiwan)

Published in SPIE Proceedings Vol. 8166:
Photomask Technology 2011
Wilhelm Maurer; Frank E. Abboud, Editor(s)

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