Atomic layer deposition of Ruthenium on different interfaces for an advanced metallization system of ICs

Nucleation effects were experimentally studied for ruthenium thin films grown by plasma-enhanced atomic layer deposition (PEALD) using O2 plasma. Bis(ethylcyclopentadienyl)ruthenium (II) (Ru(EtCp)2) was used as Ru precursor. The films with the thickness 10 nm on different underlying thin layers (interfaces), including Si, SiO2, Ta2O5, TiN, and TaN were deposited to investigate the effects of interfaces for nucleation of the Ru in ALD process. Some of the samples were previously processed in ammonia and oxygen plasma to enhance nucleation. The processes of forming barrier layers based on titanium and tantalum nitrides by plasma-enhanced atomic layer deposition were also studied. Films properties were evaluated by spectral ellipsometry, scanning electron microscopy and atomic force microscopy.