Paper
4 October 2016 Phase-independent multilayer defect repair for EUV photomasks
Shuo Zhao, Zhengqing John Qi
Author Affiliations +
Abstract
EUV mask repair techniques have primarily focused on absorber biasing to recover the imaging contrast loss originating from multilayer blank defects, while exploratory efforts have investigated local multilayer modification for compensating any through-focus Bossung asymmetry. The work here evaluates these repair techniques and attempts to expand upon them through finite-difference time-domain (FDTD) simulations. In particular, the possibility of local material deposition as an added repair technique is considered, and the interactions between various compensation strategies and illumination modes are explored. A multilayer defect repair methodology that is non-disruptive to the multilayer stack is introduced for the recovery of both the amplitude loss and phase error originating from native blank defects. The effectiveness of the compensation technique is shown to be independent of the defect type, providing a repair solution that is impartial to the phase offset induced by the multilayer defect. Significant lithographic process window improvements are reported, as compared to conventional absorber-based repair, attributed primarily to the restoration of symmetric printing behavior through defocus. This provides an alternative, viable approach to HVM multilayer defect repair.
© (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Shuo Zhao and Zhengqing John Qi "Phase-independent multilayer defect repair for EUV photomasks", Proc. SPIE 9985, Photomask Technology 2016, 998517 (4 October 2016); https://doi.org/10.1117/12.2245442
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KEYWORDS
Multilayers

Printing

Phase shifts

Coating

Photomasks

Aluminum

Critical dimension metrology

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