Ruthenium catalyst processing and oxidation for scalable complementary metal-oxide-semiconductor-compatible metal-assisted chemical etch

Mark Hrdy; Akhila Mallavarapu; Raul Lema Galindo; S.V. Sreenivasan

doi:10.1117/1.JMM.23.4.043601

12 October 2024 Ruthenium catalyst processing and oxidation for scalable complementary metal-oxide-semiconductor-compatible metal-assisted chemical etch

Mark Hrdy, Akhila Mallavarapu, Raul Lema Galindo, S.V. Sreenivasan

Author Affiliations +

Journal of Micro/Nanopatterning, Materials, and Metrology, Vol. 23, Issue 4, 043601 (October 2024). https://doi.org/10.1117/1.JMM.23.4.043601

Abstract

Background

Metal-assisted chemical etching (MacEtch) of Si is a catalyst-based etch technique that has demonstrated better performance at attaining high-aspect ratio structures than reactive ion etching but developing a complementary metal-oxide-semiconductor (CMOS)-compatible process is an ongoing challenge. Ruthenium (Ru) is a highly desirable catalyst for CMOS manufacturing but is too catalytically active.

Aim

To create a scalable Ru MacEtch process, the Ru catalyst must be tailored to have lower activity. Ru catalyst patterning must consider CMOS compatibility and fidelity of large area, nanoscale pattern transfer.

Approach

The catalytic activity of Ru and MacEtch uniformity is tailored through optimization of Ru deposition and oxidation with CMOS-compatible patterning.

Results

This report contains an entirely CMOS-compatible process for MacEtch of Si with feature dimensions down to 50 nm. To our knowledge, this is the first example of patterning a catalyst for MacEtch using dry etch processing. It also demonstrates that oxidation of the Ru catalyst can significantly reduce its catalytic activity and allow for a 100% increase in patterned area without porosity compared with previous publications.

Conclusion

A drop-in replacement to plasma etching is demonstrated for CMOS devices and CMOS-compatible foundries. Catalyst design parameters such as deposition rate and heat treatment have a great influence on MacEtch performance.

Citation Download Citation

Mark Hrdy, Akhila Mallavarapu, Raul Lema Galindo, and S.V. Sreenivasan "Ruthenium catalyst processing and oxidation for scalable complementary metal-oxide-semiconductor-compatible metal-assisted chemical etch," Journal of Micro/Nanopatterning, Materials, and Metrology 23(4), 043601 (12 October 2024). https://doi.org/10.1117/1.JMM.23.4.043601

Received: 12 March 2024; Accepted: 16 September 2024; Published: 12 October 2024

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KEYWORDS

Ruthenium

Etching

Heat treatments

Oxidation

Silicon

Nanowires

Dry etching

Background

Aim

Approach

Results

Conclusion

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