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Proceedings Paper

Automated CD-error compensation for negative-tone chemically amplified resists by zone-controlled post-exposure bake
Author(s): Lothar Berger; Peter Dress; Thomas Gairing; J. J. Chen; Ren-Guey Hsieh; Hsin-Chang Lee; Hung-Chang Hsieh
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Paper Abstract

Negative-tone chemically amplified resists (nCARs), like NEB22 are promising candidates for next-generation lithography, e.g. 90 nm and 65 nm technology node and next-generation lithography. For these resists, e-beam exposure and post-exposure bake (PEB) are most critical processes, since these resists show a strong sensitivity to post-exposure delay (PED) in vacuum during e-beam writing of about 0.5 nm/h, and in air while waiting for PEB. Further, such resists show a strong PEB temperature sensitivity of up to 8 nm/K. The multi-zone hotplate approach of the APB AFB 5500 bake system with its use prior temperature uniformity results in excellent global CD-uniformity already. However, all kinds of systematic large area effects of processes, e.g. blank coat/bake, exposure, PED, the PEB itself, etch loading, etc. may transfer in additional systematic CD-errors. Such systematic, repeatable errors can be reduced during PEB by superimposing an appropriate non-uniform temperature profile onto the regular, optimized uniform bake temperature profile, thereby compensating for such CD-non-uniformities. The required temperature profile can automatically be calculated from a suitable gobal CD measurement, determined in a typical process flow. The compensation of CD-errors resulting from vacuum PED and hotplate temperature characteristics is demonstrated here, by using automated temperature profile calculation. The global CD uniformity was improved significantly, the achieved results show a typical reduction of about 20-30%, from a total global range of about 9nm to about 6-7nm on leading-edge production photomasks.

Paper Details

Date Published: 17 December 2003
PDF: 12 pages
Proc. SPIE 5256, 23rd Annual BACUS Symposium on Photomask Technology, (17 December 2003); doi: 10.1117/12.517202
Show Author Affiliations
Lothar Berger, STEAG HamaTech AG (Germany)
Peter Dress, STEAG HamaTech AG (Germany)
Thomas Gairing, STEAG HamaTech AG (Germany)
J. J. Chen, Taiwan Semiconductor Manufacturing Co., Ltd. (Taiwan)
Ren-Guey Hsieh, Taiwan Semiconductor Manufacturing Co., Ltd. (Taiwan)
Hsin-Chang Lee, Taiwan Semiconductor Manufacturing Co., Ltd. (Taiwan)
Hung-Chang Hsieh, Taiwan Semiconductor Manufacturing Co., Ltd. (Taiwan)

Published in SPIE Proceedings Vol. 5256:
23rd Annual BACUS Symposium on Photomask Technology
Kurt R. Kimmel; Wolfgang Staud, Editor(s)

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