Cobalt subtractive etch for advanced interconnects

A. Rogozhin; A. Miakonkikh; A. Tatarintsev; I. Amirov; K. Rudenko

doi:10.1117/12.2624333

30 January 2022 Cobalt subtractive etch for advanced interconnects

A. Rogozhin, A. Miakonkikh, A. Tatarintsev, I. Amirov, K. Rudenko

Proceedings Volume 12157, International Conference on Micro- and Nano-Electronics 2021; 1215718 (2022) https://doi.org/10.1117/12.2624333
Event: International Conference on Micro- and Nano-Electronics 2021, 2021, Zvenigorod, Russian Federation

Abstract

The modern IC process consists of a 13-layer metallization stack. Critical dimensions are 30-40 nm at the M0- M2 metal layers and due to barrier resistance and electromigration reasons, copper is not the perfect choice nowadays. There are two main alternatives to copper on M0-M2 layers: cobalt and ruthenium. Return to the subtractive scheme could be a powerful solution for future interconnects although the dry etching process of the metal is required for it. In this paper, different approaches to plasma etching of cobalt are studied. CO- and halogen-containing plasmas were considered. It seems that etching in CO-based plasma is inefficient. The rate was only 2 nm/min in a wide temperature range. The low-temperature (60°C) process of the cobalt etching in BCl₃/Ar plasma was developed. The etching rate for the process was 50 nm/min. All of the considered processes are found to be aggressive toward the mask.

Citation Download Citation

A. Rogozhin, A. Miakonkikh, A. Tatarintsev, I. Amirov, and K. Rudenko "Cobalt subtractive etch for advanced interconnects", Proc. SPIE 12157, International Conference on Micro- and Nano-Electronics 2021, 1215718 (30 January 2022); https://doi.org/10.1117/12.2624333

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