19 March 2018 EUV vote-taking lithography: crazy... or not?
Author Affiliations +
Vote-taking lithography is a method for mitigating mask defects, which has been applied in the 1980’s to enhance yield. Vote-taking sums up N different mask images with identical content, each at 1/N dose, to mitigate the defects on each individual mask. The fundamental assumption is that the mask defects do not correlate in position from mask to mask, and so each individual defect will be blended with good images from the other N-1 masks. Vote-taking has recently been brought under the attention again for consideration in EUV lithography, where it might provide a temporary solution for situations in which the defectivity conditions are not yet meeting expectations.

This paper provides a thorough experimental assessment of the implementation of vote-taking, and discusses its pro’s and con’s. Based on N=4 vote-taking, we demonstrate the capability to mitigate different types of mask defects. Additionally, we found that blending different mask images brings clear benefit to the imaging, and provide experimental confirmation of improved local CDU and intra-field CDU, reduction of stochastic failures, improved overlay, ... Finally, we perform dedicated throughput calculations based on the qualification performance of ASML’s NXE:3400B scanner.

This work must be seen in the light of an open-minded search for options to optimally enable and implement EUV lithography. While defect-free masks and EUV pellicles are without argument essential for most of the applications, we investigate whether some applications could benefit from vote-taking.
Conference Presentation
© (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Joost Bekaert, Peter De Bisschop, Christophe Beral, Eric Hendrickx, Mark A. van de Kerkhof, Sander Bouten, Michiel Kupers, Guido Schiffelers, Erik Verduijn, Timothy A. Brunner, "EUV vote-taking lithography: crazy... or not?", Proc. SPIE 10583, Extreme Ultraviolet (EUV) Lithography IX, 105830I (19 March 2018); doi: 10.1117/12.2299509; https://doi.org/10.1117/12.2299509


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