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1 June 1992 Evaluation of methods to reduce linewidth variation due to topography for i-line and deep-UV lithography
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For deep submicron lithography, reduction of linewidth variation due to topography is critical. While advanced resists are available which demonstrate wide process latitude on flat substrates, their performance on realistic topography is not adequate. A new method of predicting performance over topography using data taken from flat substrates is described. The method uses data from both maximum and minimum incoupling resist thicknesses to determine the overlapping depth of focus (ODOF). The usefulness of the ODOF approach in predicting process latitude for substrates with topography is shown. Results for both I-line and deep UV imaging on poly gate level topography are presented. Results obtained with 2 top anti-reflection (TAR) layers (Hoechst Aquatar and a non-commercial TAR material) are compared to those from a dyed resist, an anti-reflection coating (ARC) and a contrast enhancement material (CEM). Methods of determining the optimal TAR thickness experimentally are presented. TAR materials give the best results for I-line.
© (1992) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Miles J. Gehm Jr., Patrick Jaenen, Veerle Van Driessche, Anne-Marie Goethals, Nandasiri Samarakone, Luc Van den Hove, and Bart Denturck "Evaluation of methods to reduce linewidth variation due to topography for i-line and deep-UV lithography", Proc. SPIE 1674, Optical/Laser Microlithography V, (1 June 1992);

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