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Proceedings Paper

Open issues in mask technology as EUV enters high volume manufacturing
Author(s): Moshe Preil; James W. Westphal
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Paper Abstract

After years of optimistic projections and false starts, 2019 is finally the year that EUV will enter volume production. Mask shop investment in EUV-capable equipment, including writing, inspection, metrology, repair, review and cleaning tools as well as related infrastructure for storage, transportation, and pellicle support has been substantial. However, in both mask shops and wafer fabs, key questions remain unanswered even as high volume manufacturing (HVM) begins in the fab. We will highlight several of these questions that still need to be answered to develop comprehensive, end-to-end strategies for mask inspection, use, and qualification strategies. In particular, we will show how uncertainty over pellicle technology options and timing cascade into a series of questions related to reticle qualification flows throughout the lifetime of a mask. Additional uncertainty comes from the lack of data on reticle contamination mechanisms during use in high-power EUV exposure tools. Concerns over hydrocarbon deposition and reaction with intense EUV photons as well as with the out-of-band DUV present in the system, will require the development of careful monitoring and re-qualification plans. Reticle requalification cycles will be gated not just by the number of wafers exposed, but by the number of times a reticle is loaded and unloaded from the scanner and how long it sits in storage between cycles. We anticipate that a combination of wafer-based and reticle-based inspection will be required to fully ensure reticle quality, especially if a pellicle solution is adopted which does not allow 193nm based inspection. These tradeoffs and uncertainties will be discussed in the context of a full, mask blank to wafer fab reticle qualification strategy for EUV volume manufacturing.

Paper Details

Date Published: 27 June 2019
PDF: 5 pages
Proc. SPIE 11178, Photomask Japan 2019: XXVI Symposium on Photomask and Next-Generation Lithography Mask Technology, 111780C (27 June 2019); doi: 10.1117/12.2536308
Show Author Affiliations
Moshe Preil, KLA Corp. (United States)
James W. Westphal, KLA Corp. (United States)

Published in SPIE Proceedings Vol. 11178:
Photomask Japan 2019: XXVI Symposium on Photomask and Next-Generation Lithography Mask Technology
Akihiko Ando, Editor(s)

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