Diffraction-based overlay metrology for double patterning technologies

Prasad Dasari; Rahul Korlahalli; Jie Li; Nigel Smith; Oleg Kritsun; Cathy Volkman

doi:10.1117/12.816590

24 March 2009 Diffraction-based overlay metrology for double patterning technologies

Prasad Dasari, Rahul Korlahalli, Jie Li, Nigel Smith, Oleg Kritsun, Cathy Volkman

Proceedings Volume 7272, Metrology, Inspection, and Process Control for Microlithography XXIII; 727212 (2009) https://doi.org/10.1117/12.816590
Event: SPIE Advanced Lithography, 2009, San Jose, California, United States

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.

Citation Download Citation

Prasad Dasari, Rahul Korlahalli, Jie Li, Nigel Smith, Oleg Kritsun, and Cathy Volkman "Diffraction-based overlay metrology for double patterning technologies", Proc. SPIE 7272, Metrology, Inspection, and Process Control for Microlithography XXIII, 727212 (24 March 2009); https://doi.org/10.1117/12.816590

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