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Published October 2022 | Published
Journal Article Open

Sensitivity enhancement of a high-resolution negative-tone nonchemically amplified metal organic photoresist for extreme ultraviolet lithography


A new class of negative-tone resist materials has been developed for electron beam and extreme ultraviolet lithography. The resist is based on heterometallic rings. From initial electron beam lithography studies, the resist performance demonstrated a resolution of 40-nm pitch but at the expense of a low sensitivity. To improve the sensitivity, we incorporated HgCl₂ and HgI₂ into the resist molecular design. This dramatically improved the resist sensitivity while maintaining high resolution. This improvement was demonstrated using electron beam and extreme ultraviolet lithography.

Additional Information

© 2022 Society of Photo-Optical Instrumentation Engineers (SPIE). Received: 9 February 2022; Accepted: 4 May 2022; Published: 2 June 2022. We acknowledge the EPSRC (UK) for funding (Grant No. EP/R023158/1) and Innovate UK for funding (project 72472). The University of Manchester also supported this work. The authors gratefully acknowledge the critical support and infrastructure provided for this work by the Kavli Nanoscience Institute at Caltech. REPW thanks the European Research Council for an Advanced Grant (ERC-2017-ADG-786734) and the EPSRC (UK) for an Established Career Fellowship (EP/R011079/1). This project has received funding from the EU-H2020 research and innovation program under Grant Agreement No. 654360 having benefitted from the access provided by PSI in Villigen within the framework of the Nanoscience Foundries and Fine Analysis Europe Transnational Access Activity. The manuscript was written through the contributions of all authors. All authors have given approval to the final version of the manuscript. These authors contributed equally; Scott M. Lewis designed the research and wrote the manuscript, Hayden R. Alty designed and programmed the Excalibur Monte Carlo Simulator software, Michaela Vockenhuber ran the XIL beamline at the PSI and performed the EUV exposures on the photoresists, Dimitrios Kazazis performed the EUV exposures and acquired the SEM images of the photoresist. Paul. L. Winpenny designed and programmed the pattern analysis software, Guy A. Derose provided the EPBG5200 EBL tool and fabricated the patterns, Axel Scherer provided the EPBG5200 EBL tool and lab facilities necessary to verify the results, Yasin Ekinci provided the XIL beam EUV exposure tool and lab facilities necessary to verify the results. Grigore A. Timco and Richard Grindell made the compounds studied. Richard E. P. Winpenny provided the chemistry facilities and lab infrastructure. EPSRC (UK) Grant EP/R023158/1; Innovate UK project 72472; European Research Council ERC-2017-ADG-786734; EPSRC (UK) EP/R011079/1.

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August 22, 2023
October 23, 2023