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Proceedings Paper

Sigma7500: an improved DUV laser pattern generator addressing sub-100-nm photomask accuracy and productivity requirements
Author(s): Henrik Sjöberg; Tord Karlin; Mats Rosling; Thomas Öström; Jonas Måhlén; Tom Newman
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Paper Abstract

As photomask pattern complexity continues to increase, it becomes more challenging to control write times of shaped e-beam tools. This raises the related concerns of increased mask costs and extended mask cycle times. A strategy for sub-100 nm technology nodes is to use high-speed DUV laser pattern generators for as many layers as possible, reserving e-beam tools for only the most critical layers. With 248 nm optics and high-NA partially coherent imaging, the Sigma7500 increases the application space available to laser pattern generators. Image profiles are steepened with phase shifting methods, and pattern fidelity is improved with on-line corner enhancement. In the Sigma architecture, mask patterns are imaged with full fidelity and addressability in each writing pass. Because of this, the Sigma7500 provides additional means to improve write time by reducing the number of exposure passes. Platform improvements have resulted in a 2-pass writing accuracy that meets the 4-pass specification of the previous system. Write time is typically under two hours in 2-pass mode, compared to approximately three hours for 4-pass. The Sigma7500 can generally be used for all binary mask layers at the 90 nm technology node, and for about half the layers at 45 nm. The ProcessEqualizerTM function addresses long range CD errors arising from mask process effects. Mask data is sized in real time to compensate for process errors related to local pattern density, and also to correct for static process CD signatures. With a through-the-lens alignment system and both grid matching and pattern matching capabilities, the tool is also suited to 2nd layer patterning for advanced phase shifting mask (PSM) applications down to 45 nm, with extendibility to 32 nm. Process integration is facilitated by the use of standard FEP-171 chemically amplified resist (CAR).

Paper Details

Date Published: 20 May 2006
PDF: 9 pages
Proc. SPIE 6283, Photomask and Next-Generation Lithography Mask Technology XIII, 628305 (20 May 2006); doi: 10.1117/12.681731
Show Author Affiliations
Henrik Sjöberg, Micronic Laser Systems AB (Sweden)
Tord Karlin, Micronic Laser Systems AB (Sweden)
Mats Rosling, Micronic Laser Systems AB (Sweden)
Thomas Öström, Micronic Laser Systems AB (Sweden)
Jonas Måhlén, Micronic Laser Systems AB (Sweden)
Tom Newman, Micronic Laser Systems AB (Sweden)

Published in SPIE Proceedings Vol. 6283:
Photomask and Next-Generation Lithography Mask Technology XIII
Morihisa Hoga, Editor(s)

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