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Proceedings Paper

Efficient simulation and optimization of wafer topographies in double patterning
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Paper Abstract

As the technology marches towards the 32nm node and beyond in semiconductor manufacturing, double patterning and double exposure techniques are currently regarded as the potential candidates to produce lines and spaces (L&S) and contact holes (C/H), respectively. In this paper, the Waveguide method, a rigorous electromagnetic field (EMF) solver, is employed to investigate the impact of wafer topographies on two specific double patterning techniques. At first, the topography effects induced by the first patterning on the second lithography process in a lithography-etch-lithographyetch (LELE) process are demonstrated. A new methodology of the bottom anti-reflective coating (BARC) optimization is proposed to reduce the impact of wafer topography on resist profiles. Additionally, an optical proximity correction (OPC) of the second lithography mask is demonstrated to compensate the wafer topography induced asymmetric deformations of line ends. Rigorous EMF simulations of lithographic exposures are also applied to investigate wafer topography effects in a freezing process. The difference between the optical properties of the frozen (first) resist and the second resist potentially causes linewidth variations. Quantitative criteria for tolerable refractive index and extinction differences between the two resist materials are given. The described studies can be used for the optimizations of topographic waferstacks, the OPC of the second litho mask, and for the development of resist materials with appropriate optical properties.

Paper Details

Date Published: 16 March 2009
PDF: 14 pages
Proc. SPIE 7274, Optical Microlithography XXII, 72740O (16 March 2009); doi: 10.1117/12.814176
Show Author Affiliations
Feng Shao, Fraunhofer Institute of Integrated Systems and Device Technology (Germany)
Peter Evanschitzky, Fraunhofer Institute of Integrated Systems and Device Technology (Germany)
Tim Fühner, Fraunhofer Institute of Integrated Systems and Device Technology (Germany)
Andreas Erdmann, Fraunhofer Institute of Integrated Systems and Device Technology (Germany)

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

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