Deposition of Ru using a metal organic Ru precursor and H₂ molecules as a non-oxidative reactant for emerging Ru interconnects

Efficient alternatives to Cu interconnects are gradually drawing attention from semiconductor industries. The complex nexus of Cu interconnects and narrow dimension architecture as required semiconductor device miniaturization further increases the devices' overall resistivity. In search of an efficient and reliable Cu interconnect replacement, we introduce plasma-free atomic layered deposition of Ru using a liquid metal-organic precursor, tricarbonyl(trimethylenemethane)ruthenium, [Ru(TMM)(CO)<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>]. Instead of conventionally used O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> reactant, we introduce H<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> as a non-oxidative reactant, optimizing all deposition conditions with respect to the already established O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> atomic layer deposition process. Precisely, a thin Ru film was deposited with excellent step coverage on a narrow trench substrate having a high aspect ratio. The post-deposition annealing (PDA) of the as-grown film demonstrated an industrially preferred low resistivity as compared to the unannealed one. The obtained high-quality, uniform Ru films, suitably low resistivity, without using any high energy plasma-enhanced techniques could serve as potential Ru interconnects to replace Cu.