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Proceedings Paper

Inspection and repair issues for Step and Flash Imprint Lithography templates
Author(s): Kevin J. Nordquist; William J. Dauksher; David P. Mancini; Douglas J. Resnick; Harald F. Hess; Donald W. Pettibone; David Adler; Kirk Bertsche; Roy White; Jeffrey E. Csuy; David Lee
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Paper Abstract

Step and Flash Imprint Lithography (S-FIL) 1X templates must eventually achieve and maintain the very low defect counts commensurate to current production masks. This requires typically fewer than ten or even no defects over the entire field and to minimize template fabrication costs and techniques must be identified to repair defects on templates when they do occur. We describe inspection and repair methodologies and how it can be applied to the imprint template. For inspection, test patterns etched onto the template enable both a die-to-die comparison, to find nuisance defects, and also calibration of sensitivity to different types of preprogrammed defects. A state of the art deep UV photomask inspection system (KLA-Tencor model 526) can detect these events with about 70 nm threshold for imprint masks using reflection mode contrast. Initial scans are made at various stages of the imprint process: the processed mask, after dicing, and after several imprints. The scans show mostly isolated point defects at a density of ~ 10 to 100 per mm2. To repair defects, studies were undertaken using RAVE’s nm650 tool which is essentially an AFM platform that relies upon a nano-machining technique for opaque defect removal. On S-FIL templates, the standard deviation for depth repairs in quartz from the target depth was found to be 3.1 nm (1σ). The spread in edge placement data for opaque line protrusions was 21.5 nm (1σ). Trench cuts through lines were successfully created with a minimum size of about 55nm. The repairs on the template were verified by imprinting the features on wafers. The range of depth offsets studied (-15 to +15) had no bearing on the imprinting process and the edge placement on wafers replicated the edge placement of the repaired templates. Trench cuts on the template were successfully filled with the imprint monomer and measured slightly larger than the minimum gap size. Finally, the imprinted wafers were used to pattern transfer features into 100nm of oxide.

Paper Details

Date Published: 6 December 2004
PDF: 11 pages
Proc. SPIE 5567, 24th Annual BACUS Symposium on Photomask Technology, (6 December 2004); doi: 10.1117/12.569846
Show Author Affiliations
Kevin J. Nordquist, Motorola Labs. (United States)
William J. Dauksher, Motorola Labs. (United States)
David P. Mancini, Motorola Labs. (United States)
Douglas J. Resnick, Motorola Labs. (United States)
Harald F. Hess, KLA-Tencor Corp. (United States)
Donald W. Pettibone, KLA-Tencor Corp. (United States)
David Adler, KLA-Tencor Corp. (United States)
Kirk Bertsche, KLA-Tencor Corp. (United States)
Roy White, RAVE LLC (United States)
Jeffrey E. Csuy, RAVE LLC (United States)
David Lee, RAVE LLC (United States)

Published in SPIE Proceedings Vol. 5567:
24th Annual BACUS Symposium on Photomask Technology
Wolfgang Staud; J. Tracy Weed, Editor(s)

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