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Proceedings Paper

Detection of lateral CD shift with scatterometry on grating structures in production layout
Author(s): Jacky Huang; Jiarui Hu; Willie Wang; Ya-Ping Lee; Chih-Ming Ke; Tsai-Sheng Gau
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Paper Abstract

In 32nm/22nm advanced technology node, double patterning lithography is considered for semiconductor manufacturing. It necessitates tightened requirement of overlay measurement, i.e. to measure the position of a pattern with respect to that of a pattern in the underlying layer. The measurement target design plays a fundamental role in overlay precision and accuracy. Typical alignment target, such as bar-in-bar or box-in-box (BIB), has precision, accuracy, and size restrictions. This prompts us to look into better alignment targets. Recently, scatterometry-based metrology and profile model capability have been extended to measure multi-level grating structures. In addition, scatterometry has been shown to be the best choice for integrated metrology to perform wafer-to-wafer control. Therefore, it makes sense to consider using scatterometry for overlay measurement. In this research, the modeling analysis is performed on the spectra taken directly from a real pattern area with grating-ongrating structure. The critical dimension (CD) at the grating on top and the lateral shift between the top and the bottom gratings can be detected simultaneously. The lateral shift between the layers can be verified with the traditional overlay box. Unlike the traditional BIB target that has micrometer CD size, the CD size of the scatterometry overlay (S_OVL) target is much closer to that on the real device. So, it can much better reflect the overlay (OVL) shift on real devices. We also studied the non-model-based S_OVL measurement using a 673-nm semiconductor laser with a 10μm x 20μm target size, wafer-to-wafer control of CD and lateral shifts on some critical layers with grating-on-grating structure, as well as the CD and OVL variations within layer and from layer to layer for double patterning.

Paper Details

Date Published: 2 April 2010
PDF: 9 pages
Proc. SPIE 7638, Metrology, Inspection, and Process Control for Microlithography XXIV, 76381Q (2 April 2010); doi: 10.1117/12.848522
Show Author Affiliations
Jacky Huang, Taiwan Semiconductor Manufacturing Co., Ltd. (Taiwan)
Jiarui Hu, Taiwan Semiconductor Manufacturing Co., Ltd. (Taiwan)
Willie Wang, Taiwan Semiconductor Manufacturing Co., Ltd. (Taiwan)
Ya-Ping Lee, Taiwan Semiconductor Manufacturing Co., Ltd. (Taiwan)
Chih-Ming Ke, Taiwan Semiconductor Manufacturing Co., Ltd. (Taiwan)
Tsai-Sheng Gau, Taiwan Semiconductor Manufacturing Co., Ltd. (Taiwan)


Published in SPIE Proceedings Vol. 7638:
Metrology, Inspection, and Process Control for Microlithography XXIV
Christopher J. Raymond, Editor(s)

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