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Proceedings Paper

157-nm photomask handling and infrastructure: requirements and feasibility
Author(s): Jerry Cullins; Edward G. Muzio
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Paper Abstract

Photomask handling is significantly more challenging for 157 nm lithography than for any previous generation of optical lithography. First, pellicle materials are not currently available which meet all the requirements for 157 nm lithography. Polymeric materials used at 193 nm higher wavelengths are not sufficiently transmissive at 157 nm, while modified fused silica materials have adequate transmission properties but introduce optical distortion. Second, the problem of molecular level contamination on the reticle must be solved. This contamination is due to the presence of oxygen, carbon dioxide, water, and other attenuators of 157 nm radiation on the mask surface. It must be removed using something other than the lithography laser due to throughput and cost of ownership considerations. Third, there is the issue of removing attenuators from under the pellicle after a material becomes available. Both the ambient atmosphere and other introduced contaminants must be removed from the space between the reticle and pellicle after cleaning but before exposure. Fourth are the potential issues for storage of reticles both during transportation from the mask shop and after it is in the wafer fab. Finally, the problems associated with operating in an optically inert dry environment must be addressed. The lack of moisture in the environment removes one of the key electrical discharge paths off of the reticle, which greatly increases the risk of electrostatic damage to the pattern (ESD). In order to address these and related issues in a timeframe consistent with the aggressive implementation plan for 157 nm lithography, International Sematech (ISMT) formed the 157 nm Reticle Handling Team in November of 1999. This paper details the most critical results to date of this industry-wide team, and gives a prognosis for successful completion of the team's primary goal: a demonstration of a feasible 157 nm reticle handling strategy by December of 2000.

Paper Details

Date Published: 14 September 2001
PDF: 9 pages
Proc. SPIE 4346, Optical Microlithography XIV, (14 September 2001); doi: 10.1117/12.435770
Show Author Affiliations
Jerry Cullins, International SEMATECH (United States)
Edward G. Muzio, International SEMATECH (United States)

Published in SPIE Proceedings Vol. 4346:
Optical Microlithography XIV
Christopher J. Progler, Editor(s)

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