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Proceedings Paper

Integration of optical inspection and metrology functions into DUV femtosecond laser repair tool for large-area FPD photomasks
Author(s): Leon Treyger; Jon Heyl; Donald Ronning; Donald Ducharme
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Paper Abstract

In this paper we describe the early stages of introduction of the inspection and metrology capabilities for the large area mask repair tools. Commercially available MRT platform was used as a basis for integration of defect repair, metrology, review, inspection, and verification functions into a single MiRT prototype system. This system was designed for large area LCD/PDP photomasks of Generation 7 and beyond. Advanced DUV femtosecond laser technology was developed for repair of both clear and opaque defects on Chrome-on-Glass masks using laser CVD and laser ablation. Specifics of the system design and architecture is discussed. Laser processing module was based on the projection optics with imaged aperture. Image formation in such optical system is reviewed and outcome of the computer simulation is compared with the experimental data. For the first time, we report results of the feasibility study of grayscale photomask repair using laser CVD technology. By carefully controlling process parameters, we were able to deposit films with different thickness and therefore variable transmittance. We also discuss die-to-database inspection of half-tone masks and capabilities of the integrated metrology and review of the repaired photomask sites. Proprietary die-to-database inspection and verification algorithms combined with distributed super-fast computer architecture allowed effective process control with accurate, repeatable, and timely measurements. Different subsystems that enable integration of repair, metrology, and inspection functions into the MiRT system are discussed.

Paper Details

Date Published: 15 May 2007
PDF: 15 pages
Proc. SPIE 6607, Photomask and Next-Generation Lithography Mask Technology XIV, 66072N (15 May 2007); doi: 10.1117/12.729006
Show Author Affiliations
Leon Treyger, Controlled Semiconductor, Inc. (United States)
Jon Heyl, Controlled Semiconductor, Inc. (United States)
Donald Ronning, Lite Enterprises Inc. (United States)
Donald Ducharme, Lite Enterprises Inc. (United States)

Published in SPIE Proceedings Vol. 6607:
Photomask and Next-Generation Lithography Mask Technology XIV
Hidehiro Watanabe, Editor(s)

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