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Journal of Micro/Nanolithography, MEMS, and MOEMS

Critical dimension scanning electron microscope local overlay measurement and its application for double patterning of complex shapes
Author(s): Shoji Hotta; Takumichi Sutani; Scott D. Halle; Daniel Moore; Chas N. Archie; Akiyuki Sugiyama; Masahiko Ikeno; Atsuko Yamaguchi; Kazuyoshi Torii
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Paper Abstract

We have developed a new local overlay measurement technique on actual device patterns using a critical dimension scanning electron microscope (CD-SEM), which can be applied to two-dimensional (2D) device structures such as a static random access memory contact hole array. CD-SEM overlay measurement can provide additional local overlay information at the site of device patterns, complementary to the optical overlay. The methodology includes the use of pattern symmetry to cancel out many process effects and reduce measurement uncertainty. CD-SEM overlay metrology was compared with conventional optical overlay metrology in terms of measurement uncertainty and overlay model analysis, and very good correlation was confirmed. The developed methodology was applied to local overlay measurement of double patterning contact hole layers of leading edge devices. The local overlay distribution was obtained across the device area, and spatial correlation of the overlay error vectors was examined over a large range of distances. The applications of CD-SEM overlay metrology were explored, and methodologies were introduced to examine both the overlay of double patterning contacts at the edge of an array and lithographic process-induced overlay shift of contacts. Finally, a hybrid optical CD-SEM overlay metrology was introduced in order to capture a high order, device weighted overlay response.

Paper Details

Date Published: 1 April 2011
PDF: 20 pages
J. Micro/Nanolith. 10(2) 023014 doi: 10.1117/1.3599867
Published in: Journal of Micro/Nanolithography, MEMS, and MOEMS Volume 10, Issue 2
Show Author Affiliations
Shoji Hotta, Hitachi America, Ltd. (United States)
Takumichi Sutani, Hitachi America, Ltd. (Japan)
Scott D. Halle, IBM Corp. (United States)
Daniel Moore, IBM Corp. (United States)
Chas N. Archie, IBM Corp. (United States)
Akiyuki Sugiyama, Hitachi High-Technologies Corp. (Japan)
Masahiko Ikeno, Hitachi High-Technologies Corp. (Japan)
Atsuko Yamaguchi, Hitachi, Ltd. (Japan)
Kazuyoshi Torii, Hitachi, Ltd. (Japan)

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