Inhibitor-Free Area-Selective Atomic Layer Deposition with Feature Size Down to Nearly 10 nm

Abstract

Area-selective atomic layer deposition (AS-ALD) is gaining widespread attention due to the urgent demand for a self-aligned and “bottom-to-top” fabrication process in advanced semiconductor technology. In this study, an innovative concept of the “atomic layer nucleation engineering (ALNE)” and “surface recovery (SR)” techniques is proposed to realize AS-ALD of Al2O3 between metal (W) and dielectric (SiO2) without the involvement of inhibitors. The ALNE treatment is utilized to selectively remove the weakly adsorbed precursors on the metal surface, and the SR process can eliminate the oxidized layer on the metal surface caused by the exposure of oxidants in the ALD process. Accordingly, the AS-ALD with ∼100% selectivity is achieved up to 100 ALD cycles with a considerable difference in an Al2O3 thickness of ∼11.2 nm between the SiO2 and W surfaces. The accomplishment of AS-ALD is also demonstrated on the SiO2/W patterned substrates with the feature size scaling from 75 μm to ∼10 nm. Hence, the inhibitor-free AS-ALD implemented by the ALNE and SR techniques is a critical breakthrough for the further progress of Moore’s law.