11 May 2007 Optimization of electrostatic chuck for mask-blank flatness control in extreme ultraviolet lithography
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Proceedings Volume 6607, Photomask and Next-Generation Lithography Mask Technology XIV; 66070J (2007) https://doi.org/10.1117/12.728933
Event: Photomask and Next-Generation Lithography Mask Technology XIV, 2007, Yokohama, Japan
Abstract
Overlay requirements of Extreme Ultra-violet Lithography (EUVL) dictate reticle flatness errors of 50nm or less. During the early phase of EUVL development, it was decided that an electrostatic chuck was required to flatten EUVL masks to these specifications. However current experience and test data have demonstrated that it will be very difficult to reach the desired mask flatness goal without a thorough understanding and advanced control of the echucking process. The results of a parametric model study are reported in this paper. In this study we calculated the chucking force dependence of activating voltage, e-chuck geometry, film material, and pin design, and then proposed an optimized chuck design. We have also engaged in a material study for the mask backside coating for the purpose of reducing flatness errors and minimizing backside particle generation. We have also designed and built an automated, vacuum based, interferometric metrology tool to enable e-chucking experimentation. An early status report of this tool will be included in this paper.
© (2007) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Emily Y. Shu, "Optimization of electrostatic chuck for mask-blank flatness control in extreme ultraviolet lithography", Proc. SPIE 6607, Photomask and Next-Generation Lithography Mask Technology XIV, 66070J (11 May 2007); doi: 10.1117/12.728933; https://doi.org/10.1117/12.728933
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