TY - JOUR
T1 - Effect of Hydrogen Ion Energy in the Process of Reactive Ion Etching of Sn Thin Films by Hydrogen Plasmas
AU - Ji, Mengran
AU - Nagata, Ryo
AU - Uchino, Kiichiro
N1 - Funding Information:
The authors would like to thank Dr. Y. Kawai, Emeritus Professor of Kyushu University, for useful discussions. This work was supported by JSPS KAKENHI, Grant Number 18K03600.
Publisher Copyright:
© 2021 The Japan Society of Plasma Science and Nuclear Fusion Research
PY - 2021
Y1 - 2021
N2 - One of the problems in extreme ultraviolet (EUV) lithography is the deterioration in the reflectivity of the EUV mirror owing to the deposition of tin (Sn) debris. Such Sn adhesion films can be etched by hydrogen ions and atoms through a chemical reaction, forming a volatile SnH4 gas. In this study, the dependence of the hydrogen ion energy on the Sn etching was investigated. Samples covered by Sn thin films and with various applied bias voltages were exposed to hydrogen plasmas. The etched thicknesses of the Sn films were quantitatively analyzed using X-ray fluorescence. As a result, it was found that the threshold ion energy is approximately 7 eV, and that the peak of the Sn atom yield per hydrogen ion, which is the value indicating the efficiency of the reactive ion etching, is obtained at a hydrogen ion energy of approximately 14 eV.
AB - One of the problems in extreme ultraviolet (EUV) lithography is the deterioration in the reflectivity of the EUV mirror owing to the deposition of tin (Sn) debris. Such Sn adhesion films can be etched by hydrogen ions and atoms through a chemical reaction, forming a volatile SnH4 gas. In this study, the dependence of the hydrogen ion energy on the Sn etching was investigated. Samples covered by Sn thin films and with various applied bias voltages were exposed to hydrogen plasmas. The etched thicknesses of the Sn films were quantitatively analyzed using X-ray fluorescence. As a result, it was found that the threshold ion energy is approximately 7 eV, and that the peak of the Sn atom yield per hydrogen ion, which is the value indicating the efficiency of the reactive ion etching, is obtained at a hydrogen ion energy of approximately 14 eV.
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U2 - 10.1585/pfr.16.1406003
DO - 10.1585/pfr.16.1406003
M3 - Article
AN - SCOPUS:85101660971
SN - 1880-6821
VL - 16
SP - 1406003-1-1406003-5
JO - Plasma and Fusion Research
JF - Plasma and Fusion Research
ER -