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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 157nm lithography than for any previous generation of optical lithography. First, pellicle materials are not currently available which meet all the requirements for 157nm lithography. Polymeric materials used at 193nm higher wavelengths are not transmissive at 157nm, while modified fused silica materials have adequate transmission and durability but have mechanical issues that need to be resolved. 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 157nm 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. Forth 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 electro-static damage to the pattern (ESD).

Paper Details

Date Published: 5 September 2001
PDF: 9 pages
Proc. SPIE 4409, Photomask and Next-Generation Lithography Mask Technology VIII, (5 September 2001); doi: 10.1117/12.438400
Show Author Affiliations
Jerry Cullins, International SEMATECH (United States)
Edward G. Muzio, International SEMATECH (United States)

Published in SPIE Proceedings Vol. 4409:
Photomask and Next-Generation Lithography Mask Technology VIII
Hiroichi Kawahira, Editor(s)

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