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Proceedings Paper

Diffraction-based overlay metrology for double patterning technologies
Author(s): Prasad Dasari; Rahul Korlahalli; Jie Li; Nigel Smith; Oleg Kritsun; Cathy Volkman
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Paper Abstract

The extension of optical lithography to 32nm and beyond is made possible by Double Patterning Techniques (DPT) at critical levels of the process flow. The ease of DPT implementation is hindered by increased significance of critical dimension uniformity and overlay errors. Diffraction-based overlay (DBO) has shown to be an effective metrology solution for accurate determination of the overlay errors associated with double patterning [1, 2] processes. In this paper we will report its use in litho-freeze-litho-etch (LFLE) and spacer double patterning technology (SDPT), which are pitch splitting solutions that reduce the significance of overlay errors. Since the control of overlay between various mask/level combinations is critical for fabrication, precise and accurate assessment of errors by advanced metrology techniques such as spectroscopic diffraction based overlay (DBO) and traditional image-based overlay (IBO) using advanced target designs will be reported. A comparison between DBO, IBO and CD-SEM measurements will be reported. . A discussion of TMU requirements for 32nm technology and TMU performance data of LFLE and SDPT targets by different overlay approaches will be presented.

Paper Details

Date Published: 24 March 2009
PDF: 12 pages
Proc. SPIE 7272, Metrology, Inspection, and Process Control for Microlithography XXIII, 727212 (24 March 2009); doi: 10.1117/12.816590
Show Author Affiliations
Prasad Dasari, Nanometrics Inc. (United States)
Rahul Korlahalli, Nanometrics Inc. (United States)
Jie Li, Nanometrics Inc. (United States)
Nigel Smith, Nanometrics Inc. (United States)
Oleg Kritsun, GLOBAL FOUNDRIES Inc. (United States)
Cathy Volkman, GLOBAL FOUNDRIES Inc. (United States)


Published in SPIE Proceedings Vol. 7272:
Metrology, Inspection, and Process Control for Microlithography XXIII
John A. Allgair; Christopher J. Raymond, Editor(s)

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