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Proceedings Paper

Etch challenges for DSA implementation in CMOS via patterning
Author(s): P. Pimenta Barros; S. Barnola; A. Gharbi; M. Argoud; I. Servin; R. Tiron; X. Chevalier; C. Navarro; C. Nicolet; C. Lapeyre; C. Monget; E. Martinez
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Paper Abstract

This paper reports on the etch challenges to overcome for the implementation of PS-b-PMMA block copolymer’s Directed Self-Assembly (DSA) in CMOS via patterning level. Our process is based on a graphoepitaxy approach, employing an industrial PS-b-PMMA block copolymer (BCP) from Arkema with a cylindrical morphology. The process consists in the following steps: a) DSA of block copolymers inside guiding patterns, b) PMMA removal, c) brush layer opening and finally d) PS pattern transfer into typical MEOL or BEOL stacks. All results presented here have been performed on the DSA Leti’s 300mm pilot line. The first etch challenge to overcome for BCP transfer involves in removing all PMMA selectively to PS block. In our process baseline, an acetic acid treatment is carried out to develop PMMA domains. However, this wet development has shown some limitations in terms of resists compatibility and will not be appropriated for lamellar BCPs. That is why we also investigate the possibility to remove PMMA by only dry etching. In this work the potential of a dry PMMA removal by using CO based chemistries is shown and compared to wet development. The advantages and limitations of each approach are reported. The second crucial step is the etching of brush layer (PS-r-PMMA) through a PS mask. We have optimized this step in order to preserve the PS patterns in terms of CD, holes features and film thickness. Several integrations flow with complex stacks are explored for contact shrinking by DSA. A study of CD uniformity has been addressed to evaluate the capabilities of DSA approach after graphoepitaxy and after etching.

Paper Details

Date Published: 28 March 2014
PDF: 10 pages
Proc. SPIE 9054, Advanced Etch Technology for Nanopatterning III, 90540G (28 March 2014); doi: 10.1117/12.2046267
Show Author Affiliations
P. Pimenta Barros, CEA-LETI (France)
S. Barnola, CEA-LETI (France)
A. Gharbi, CEA-LETI (France)
M. Argoud, CEA-LETI (France)
I. Servin, CEA-LETI (France)
R. Tiron, CEA-LETI (France)
X. Chevalier, Arkema S.A. (France)
C. Navarro, Arkema S.A. (France)
C. Nicolet, Arkema S.A. (France)
C. Lapeyre, CEA-LETI (France)
C. Monget, STMicroelectronics (France)
E. Martinez, CEA-LETI (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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