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Proceedings Paper

Achieving overlay budgets for double patterning
Author(s): Andrew J. Hazelton; Nobutaka Magome; Shinji Wakamoto; Akira Tokui; Céline Lapeyre; Sébastien Barnola; Guillaume Jullien; Vincent Salvetat
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Paper Abstract

The problem of the alignment tree for double patterning (DP) is presented. When the 2nd DP exposure is aligned to the underlying zero layer, the space CD uniformity is shown to be well outside the budget for the 32 nm HP node. Aligning the 2nd DP layer to the zero layer gives better overlay results, but aligning the 2nd DP pattern to the 1st DP pattern gives results well within the overlay requirements for the 32 nm HP. Aligning the 2nd DP layer to the 1st DP layer is recommended to give the best CD uniformity and overlay results. Experimental results show, qualitatively, the CD uniformity is significantly worse when the 2nd pattern is aligned to the zero layer, but the overlay for both alignment trees could be corrected to roughly the same levels. The raw overlay data shows a significantly different signature for the two alignment trees, possibly caused by alignment mark signal differences between the marks on the zero and 1st layers, or distortion of the zero layer after the first etch. The requirements for a DP exposure tool were reviewed and can be summarized as improved dose control, improved overlay performance, and significantly higher throughput.

Paper Details

Date Published: 16 March 2009
PDF: 11 pages
Proc. SPIE 7274, Optical Microlithography XXII, 72740X (16 March 2009); doi: 10.1117/12.813599
Show Author Affiliations
Andrew J. Hazelton, Nikon Corp. (Japan)
Nobutaka Magome, Nikon Corp. (Japan)
Shinji Wakamoto, Nikon Corp. (Japan)
Akira Tokui, Nikon Corp. (Japan)
Céline Lapeyre, CEA/LETI-Minatec (France)
Sébastien Barnola, CEA/LETI-Minatec (France)
Guillaume Jullien, CEA/LETI-Minatec (France)
Vincent Salvetat, Nikon Precision Europe GmbH (Germany)

Published in SPIE Proceedings Vol. 7274:
Optical Microlithography XXII
Harry J. Levinson; Mircea V. Dusa, Editor(s)

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