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Proceedings Paper

Effect of etch pattern transfer on local overlay (OVL) margin in 28nm gate integration.
Author(s): Onintza Ros; Pascal Gouraud; Bertrand Le-Gratiet; Christian Gardin; Julien Ducoté; Erwine Pargon
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Paper Abstract

One of the main process control challenges in logic process integration is the contact to gate overlay. Usual ways for overlay control are run to run corrections (high order process corrections) and scanner control (baseliner control loop) to keep overlay within the very tight ITRS specifications, i.e. 7nm mean+3sigma. It is known that process integration can lead to specific overlay distortion (CMP, thermal treatment etc…) which are usually partly handled by high order process corrections at scanner level. In addition, recently we have shown that etch process can also lead to local overlay distortions, especially at the wafer edge [1]. In this paper we look into another overlay distortion level which can happen during etch processes. We will show that resist cure steps during gate patterning affect lithography defined profiles leading to local pattern shifting. This so called gate shifting has been characterized by etch process partitioning during a typical high-K metal gate patterning with spinon carbon and Si-ARC lithography stack onto a high-K metal gate / poly-silicon / oxide hard mask stack. We will show that modifying the resist-cure / Si-ARC open chemistry strongly contributes to gate shifting reduction by an equivalent of 40% overlay margin reduction.

Paper Details

Date Published: 28 March 2014
PDF: 10 pages
Proc. SPIE 9054, Advanced Etch Technology for Nanopatterning III, 905406 (28 March 2014); doi: 10.1117/12.2042080
Show Author Affiliations
Onintza Ros, STMicroelectronics (France)
Pascal Gouraud, STMicroelectronics (France)
Bertrand Le-Gratiet, STMicroelectronics (France)
Christian Gardin, STMicroelectronics (France)
Julien Ducoté, STMicroelectronics (France)
Erwine Pargon, LTM CNRS (France)

Published in SPIE Proceedings Vol. 9054:
Advanced Etch Technology for Nanopatterning III
Gottlieb S. Oehrlein; Qinghuang Lin; Ying Zhang, Editor(s)

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