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Ru thin films were deposited by plasma enhanced atomic layer deposition using MethylCyclopentadienylPyrrolylRuthenium (MeCpPy)Ru and N2/NH3 plasma. The growth characteristics have been studied on titanium nitride or tantalum nitride substrates of various thicknesses. On SiO2, a large incubation period has been observed, which can be resolved by the use of a metal nitride layer of ∼ 0.8 nm. The growth characteristics of Ru layers deposited on ultra-thin metal nitride layers are similar to those on thick metal nitride substrates despite the fact that the metal nitride layers are not fully closed. Scaled Ru/metal nitride stacks were deposited in narrow lines down to 25 nm width. Thinning of the metal nitride does not impact the conformality of the Ru layer in the narrow lines. For the thinnest lines the Ru deposited on the side wall showed a more granular structure when compared to the bottom of the trench, which is attributed to the plasma directionality during the deposition process. [ABSTRACT FROM AUTHOR]

Abstract: Atomic layer deposition is a promising technique to deposit conformal, nm-thin metal barriers in high-aspect-ratio trenches. However, exactly because of its excellent conformality, the deposition can also occur inside the nanopores of the most advanced low-k materials. In this work, the mechanisms of atomic layer deposition on and in low-k, porous dielectric films were studied, using HfO2 as a test material. Exhaustive analyses showed firstly that the HfCl4 precursor penetrated uniformly in the pores throughout a 44nm thick low-k film. Secondly, it was shown that the pores were sealed as function of precursor size, i.e. there are conditions where the pores became inaccessible for HfCl4, while the – smaller – H2O molecules could still penetrate the pores. From these analyses, a deposition model was proposed. [Copyright &y& Elsevier]