使用负离子液体离子源蚀刻玻璃，硅和二氧化硅

严学俭

Etching of glass, silicon, and silicon dioxide using negative ionic liquid ion sources

使用负离子液体离子源蚀刻玻璃，硅和二氧化硅

Journal of Vacuum Science & Technology B 36, 052601 (2018);

https://doi.org/10.1116/1.5034131

Tiantong Xu1, Zhi Tao1, and Paulo C. Lozano2,a)
Hide Affiliations
1School of Energy and Power Engineering, Beihang University, 37 Xueyuan Road, Beijing 100191, China
2Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139
a)Electronic mail: plozano@mit.edu

ABSTRACT
摘要

Ionic liquid ion sources have been proposed as a new type of ion source for focused ion beam and broad ion beam applications.
In this paper, the ionic liquid EMI-BF4 (1-ethyl-3-methylimidazolium tetrafluoroborate) was used as an ion source to generate negatively charged ions and irradiate glass (Pyrex 7740), silicon, and silicon dioxide targets. The results indicate that negative EMI-BF4 ion beams can prevent issues related to surface charge accumulation on dielectric substrates, achieving etching selectivities of SiO2:Si of at least 1.55. The etching rate increases on glass, silicon, and silicon dioxide at higher ion landing energies. It is shown that the negative EMI-BF4 beam has a higher yield than traditional metal gallium ion beams, likely due to the chemical reactivity of fluorine radicals. This effect is also noticeable when compared to results using positive EMI-BF4 beams.

离子液体离子源作为用作聚焦离子束和宽离子束应用的新型离子源已经在业界提出。在本文中，离子液体EMI-BF4 (1-ethyl-3-methylimidazolium tetrafluoroborate)（1-乙基-3-甲基咪唑四氟硼酸盐）用作离子源以产生带负电的离子，并照射玻璃（Pyrex 7740），硅和二氧化硅靶。研究结果表明，带负电的EMI-BF4离子束可以防止与介电基板上的表面电荷累积相关的问题，实现SiO2:Si的蚀刻选择性至少为1.55。在较高的离子抵达能量的情况下，在玻璃、硅和二氧化硅上的蚀刻速率增加。这个结果表明，带负电的EMI-BF4束流比传统金属镓离子束具有更高的产率，这可能是由于氟自由基的化学反应性。与使用带正电的EMI-BF4束的结果相比较，这种效果也很明显。