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Proceedings Paper

Full phase-shifting methodology for 65-nm node lithography
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Paper Abstract

A new methodology for completely phase-shifting a poly layout without creating local phase conflicts was proposed for lithographic techniques combining one phase-shifting mask and one binary mask exposure1. Critical and non-critical areas of the layout are identified and phase conflicts are avoided by splitting the shifter regions from non-critical areas to non-critical areas without crossing critical areas. The out-of-phase splits of the shifter regions are removed using the binary exposure. Simulation results and experimental data collected for 90nm technology node show no sign of process latitude loss around the areas where the shifters are split. The overlay latitude is commensurate with 90nm technology scanner requirements (tool to itself). Simulation work shows that the two exposures are balancing each other out of focus in the 45-degree cut regions thus ensuring large focus latitude. The focus latitude reported is larger than the main feature process latitude; this result was confirmed experimentally. A set of phase-shifting design rules commensurate with an aggressive 65nm node technology (140nm pitch) was put together. Under these conditions, we have identified certain types of cuts that should be avoided during the generation of the phase-shifting layout; this is primarily the case for cuts in “elbow” structures which exhibit limited process latitude. Other cuts like line-end cuts will have to be modified. In this case we have proposed a side cut when the line-end is facing a perpendicular line with a minimum spacing. Despite these restrictions, test structures for the 65nm technology node were successfully converted with no phase conflicts. Experimental verification done on test structures using a 0.75 NA, 193nm scanner demonstrates 0.33 k1 capability using the full phase methodology.

Paper Details

Date Published: 26 June 2003
PDF: 12 pages
Proc. SPIE 5040, Optical Microlithography XVI, (26 June 2003); doi: 10.1117/12.485440
Show Author Affiliations
Christophe Pierrat, Synopsys, Inc. (United States)
Frank A. J. M. Driessen, Numerical Technologies, Inc. (Germany)
Geert Vandenberghe, IMEC (Belgium)


Published in SPIE Proceedings Vol. 5040:
Optical Microlithography XVI
Anthony Yen, Editor(s)

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