Atomic layer deposition of Ru in nanoTSV with high coverage and low resistivity

Abstract

With the advancement of Moore's Law, the metal linewidth has gradually reduced and Cu interconnection has lost its advantages. This paper explores the advantage of ruthenium (Ru) as a next-generation interconnection material. An Ru film with a resistivity of 15 μΩ cm and roughness of 0.8 nm was fabricated via atomic layer deposition (ALD) using the metal–organic precursor (bis(ethylcyclopentadienyl)ruthenium [Ru(EtCp)₂]) and oxygen as the reactant. Excellent step coverage and filling in nanoTSV arrays with a critical dimension (CD) of 30 nm and an aspect ratio (AR) of approximately 15 demonstrate that the reported process is highly promising for fabricating Ru as a replacement for Cu interconnects in advanced integrated circuits (ICs).