Area-Selective Deposition by a Combination of Organic Film Passivation and Atomic Layer Deposition

Abstract

Area-Selective Deposition (ASD) has the potential to enable self-aligned patterning schemes, which are implemented in the effort of keeping pace with the more and more challenging downscaling of the integrated circuit components. ASD can be achieved by exploiting surface-sensitive deposition techniques, such as Atomic Layer Deposition (ALD). However, the inherent selectivity of ALD is confined to very few ALD cycles (very thin films). Self-Assembled Monolayers (SAMs) are evaluated as a metal passivation coating to extend the ASD inhibition window. We present a successful strategy to achieve the selective deposition of Al oxide on Cu/SiO2 patterned substrate down to 50 nm half-pitch (HP) lines. We exploit the selective chemisorption of 1-octadecylthiol (ODT) on Cu to confine Al2O3 deposition on Si oxide. A study of ODT deposition on Cu allows to determine the best deposition conditions, which enable the demonstration of ASD of 6 nm Al2O3 film at relevant nano-scale dimensions. Selectivity toward Cu is demonstrated through the absence of Al signal in energy dispersive X-ray spectroscopy.