Area-selective atomic layer deposition (AS-ALD) holds great potential for advancing device manufacturing.¹ Recently, outstanding progress on this topic has been made in terms of understanding and developing highly selective processes for various material systems; some of these processes have already been transferred into fabs.²

In this work we provide an overview of AS-ALD of silicon-based materials with high selectivity and high throughput, especially silicon oxide and nitride. While the selectivity is mostly governed by the method of choice and the underpinning chemistry, the aspect of high-throughput is ensured by using spatial ALD, which is, in our case, performed at atmospheric pressure.

The processes presented here comprise three steps: selective inhibitor chemisorption, plasma-based spatial ALD and spatial back-etching. Particular focus is given to the choice of inhibitors as the most critical step in enabling high-selectivity. Here, density functional theory (DFT) calculations have been employed to unveil the chemistries governing the selectivity for the two different inhibitors within the same growth system. General guidelines on the inhibitor chemistries are derived by combining experimental and DFT results.

Finally, process details and effect of plasma chemistries on different surfaces are discussed in an effort to expand the selectivity toolbox to other silicon-based materials.

[1] A. Mameli, et al., “Area-Selective Atomic Layer Deposition of SiO₂ using acetylacetone as a chemoselective inhibitor in an ABC-type cycle”, ACS Nano, 11, 9303, 2017.

[2] H.-P. Chen, , et al., “Fully Self-Aligned Via Integration for Interconnect Scaling Beyond 3nm Node”, IEDM 2021, paper 22-1.