Etched multilayer mask in EUV lithography for 16 nm node and below

Kim, Guk-Jin; Yeung, Michael S.; Barouch, Eytan; Oh, Hye−Keun

doi:10.1117/12.2069404

Cited by 3 publications

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References 4 publications

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“…[3][4][5][6] Moreover, Kim et al also confirmed this observation by numerical analysis. 7,8 However, the mask structure should be taken into account when dealing with the mask fabrication processes, such as patterned mask inspection, 9-13 critical dimension measurement (CD metrology), 14,15 mask repair, 16,17 and cleaning. 18 Takai et al reported that the reduction of the ML stack down to 20 pairs effectively avoided the collapse of the lines by the cleaning process.…”

Section: Introductionmentioning

confidence: 99%

Pattern inspection of etched multilayer extreme ultraviolet mask

Iida¹,

Hirano²,

Amano³

et al. 2016

J. Micro/Nanolith. MEMS MOEMS

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Abstract. Patterned mask inspection for an etched multilayer (ML) extreme ultraviolet mask was investigated. In order to optimize the mask structure from the standpoint of a pattern inspection the mask structure not only from the standpoint of a pattern inspection by using a projection electron microscope but also by using a projection electron microscope but also by considering the other fabrication processes using electron beam techniques such as critical dimension metrology and mask repair, we employed a conductive layer between the ML and substrate. By measuring the secondary electron emission coefficients of the candidate materials for the conductive layer, we evaluated the image contrast and the influence of the charging effect. In the cases of 40-pair ML, 16-nm-sized extrusion and intrusion defects were found to be detectable more than 10 sigma in half pitch 44, 40, and 32 nm line-and-space patterns. Reducing 40-pair ML to 20-pair ML degraded the image contrast and the defect detectability. However, by selecting B 4 C as a conductive layer, 16-nm-sized defects and etching residues remained detectable. The 16-nm-sized defects were also detected after the etched part was refilled with Si. A double-layer structure with 2.5-nm-thick B 4 C on metal film used as a conductive layer was found to have sufficient conductivity and also was found to be free from the surface charging effect and influence of native oxide. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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