New oxidants for thermal atomic layer etching of Cu

Persi Panariti; Adam S. Hock

doi:10.1117/12.3009007

9 April 2024 New oxidants for thermal atomic layer etching of Cu

Persi Panariti, Adam S. Hock

Proceedings Volume 12958, Advanced Etch Technology and Process Integration for Nanopatterning XIII; 129580I (2024) https://doi.org/10.1117/12.3009007
Event: SPIE Advanced Lithography + Patterning, 2024, San Jose, California, United States

Abstract

Thermal Atomic Layer Etching (ALE) has received attention in recent years as an emerging semiconductor fabrication technique, as the device dimensions are scaling down to only a few nm. Thermal ALE has the ability to etch material isotropically, which is especially useful for high aspect ratio features. Copper ALE is of considerable interest since Cu is still the metal of choice for interconnects. In order to etch a Cu thin film conformally, the first step (surface oxidation) needs to be carefully controlled. Currently used oxidants, like ozone, hydrogen peroxide or oxygen plasma tend to damage the copper surface and oxidize it up to a few nm deep. These are undesirable outcomes for ALE, because the surface should remain as uniform as possible post oxidation, so that the etch step yields a smooth and conformal Cu surface. Therefore, there is a need for more tunable oxidants which allow for better control of the oxidation strength and depth of Cu thin films. In this paper, we report new, mild oxidants for Cu ALE. The oxidation strength of these reagents has been probed by in-situ x-ray Absorption Spectroscopy and one of them has been tested in real ALE conditions together with a known etch ligand (hexafluoroacetylaceton) and probed by in-situ QCM.

Conference Presentation

(2024) Published by SPIE. Downloading of the abstract is permitted for personal use only.

Citation Download Citation

Persi Panariti and Adam S. Hock "New oxidants for thermal atomic layer etching of Cu", Proc. SPIE 12958, Advanced Etch Technology and Process Integration for Nanopatterning XIII, 129580I (9 April 2024); https://doi.org/10.1117/12.3009007

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