Share Email Print
cover

Proceedings Paper

Overlay accuracy of EUV1 using compensation method for nonflatness of mask
Format Member Price Non-Member Price
PDF $14.40 $18.00

Paper Abstract

Two EUVL masks were made using the compensation method for nonflatness of a mask; and the EUV1 was used to evaluate the resulting overlay accuracy. For the same mask, the reproducibility of the intra-field overlay errors was better than 1 nm (3σ) without linear components; and that of the flatness was better than 20 nm PV. In contrast, the overlay errors were about 3 nm (3σ) for the two masks. The main cause of this degradation in overlay accuracy might be the difference in mask flatness (~260 nm PV). Using overlay patterns corrected by the compensation method reduced the overlay errors to about 2.5 nm (3σ). Although the compensation method produced only a small change, it definitely improved the intra-field overlay of the EUV1. Furthermore, the EUV1 was used to evaluate the intra-wafer overlay for 23 shots. The single-machine overlay (SMO) was found to be better than 4.5 nm (Mean + 3σnonlinear), and the mix-and-match overlay (MMO) between the EUV1 and an ArF immersion scanner (NSR-S610C) was about 20 nm (Mean + 3σnonlinear). The main cause of the MMO errors might be the nonflatness of the mask and wafer chucks of the EUV1. Thus, the chucks must be made flatter to reduce MMO errors. This work was supported in part by NEDO.

Paper Details

Date Published: 8 April 2011
PDF: 11 pages
Proc. SPIE 7969, Extreme Ultraviolet (EUV) Lithography II, 796936 (8 April 2011); doi: 10.1117/12.879340
Show Author Affiliations
Yuusuke Tanaka, MIRAI-Semiconductor Leading Edge Technologies, Inc. (Japan)
Takashi Kamo, MIRAI-Semiconductor Leading Edge Technologies, Inc. (Japan)
Kazuya Ota, MIRAI-Semiconductor Leading Edge Technologies, Inc. (Japan)
Hiroyuki Tanaka, MIRAI-Semiconductor Leading Edge Technologies, Inc. (Japan)
Osamu Suga, MIRAI-Semiconductor Leading Edge Technologies, Inc. (Japan)
Masamitsu Itoh, Toshiba Corp. (Japan)
Shusuke Yoshitake, NuFlare Technology, Inc. (Japan)


Published in SPIE Proceedings Vol. 7969:
Extreme Ultraviolet (EUV) Lithography II
Bruno M. La Fontaine; Patrick P. Naulleau, Editor(s)

© SPIE. Terms of Use
Back to Top