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Proceedings Paper

Reworkable spin-on trilayer materials: optimization of rework process and solutions for manufacturability
Author(s): Ruzhi Zhang; Allen G. Timko; John Zook; Yayi Wei; Lyudmila Pylneva; Yi Yi; Chenghong Li; Hengpeng Wu; Dalil Rahman; Douglas S. McKenzie; Clement Anyadiegwu; Ping-Hung Lu; Mark Neisser; Ralph R. Dammel; Ron Bradbury; Timothy Lee
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Paper Abstract

Trilayer stacks with alternating etch selectivity were developed and extensively investigated for high NA immersion lithography at 32nm node and beyond. The conveyance of pattern transfer function from photoresist to Si-containing bottom anti-reflective coating (Si-BARC) and carbonrich underlayer hard-mask (UL) elegantly solved the small etch budget issue for ultra-thin photoresists in immersion lithography. However, due to the hybrid nature of Si-BARC, many different behaviors were observed in comparison to conventional BARC. Lithographic performance, stability, and reworkability were among the most challenging issues for trilayer scheme. Despite of the rapid improvement in lithographic performance and stability of trilayer materials reported by several papers, the rework and cleaning of trilayer materials by wet chemistry remained a challenging problem for manufacturability. The dual function requirement of reflection control and pattern transfer (i.e. hard-masking) for spin-on Si-BARC mandates hybrid materials. Si-BARC containing both organic moiety and inorganic backbone were extensively studied and demonstrated excellent performance. However, the hybrid nature of Si-BARC necessitates the revisit of different wet chemistries and process adjustment is essential to achieve desirable results. In addition, the similarity in chemical structures between Si-BARC and low-κ dielectrics demands subtle rework differentiation by wet chemistry from a chemistry point of view. In our development, we strived to identify rework solutions for trilayer materials in both front-end-of-line (FEOL) and back-end-of-line (BEOL) applications. Rework solutions including diluted HF, Piranha, and low-κ compatible strippers were extensively investigated. The optimization of solution mixture ratios and processing conditions was systematically studied. Thorough defect inspection after rework was performed to ensure the readiness for manufacturability. Extensive Piranha rework study on stack wafers and monitor wafers were carried out and excellent results are reported.

Paper Details

Date Published: 1 April 2009
PDF: 12 pages
Proc. SPIE 7273, Advances in Resist Materials and Processing Technology XXVI, 72732O (1 April 2009); doi: 10.1117/12.814708
Show Author Affiliations
Ruzhi Zhang, AZ Electronic Materials (United States)
Allen G. Timko, AZ Electronic Materials (United States)
John Zook, AZ Electronic Materials (United States)
Yayi Wei, AZ Electronic Materials (United States)
Lyudmila Pylneva, AZ Electronic Materials (United States)
Yi Yi, AZ Electronic Materials (United States)
Chenghong Li, AZ Electronic Materials (United States)
Hengpeng Wu, AZ Electronic Materials (United States)
Dalil Rahman, AZ Electronic Materials (United States)
Douglas S. McKenzie, AZ Electronic Materials (United States)
Clement Anyadiegwu, AZ Electronic Materials (United States)
Ping-Hung Lu, AZ Electronic Materials (United States)
Mark Neisser, AZ Electronic Materials (United States)
Ralph R. Dammel, AZ Electronic Materials (United States)
Ron Bradbury, AZ Electronic Materials (United States)
Timothy Lee, AZ Electronic Materials (United States)

Published in SPIE Proceedings Vol. 7273:
Advances in Resist Materials and Processing Technology XXVI
Clifford L. Henderson, Editor(s)

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