Aluminide intermetallics for advanced interconnect metallization: thin film studies
Jean-Philippe Soulié, Zsolt Tökei, Johan Swerts, Christoph Adelmann
Abstract
AlNi, Al <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Sc, AlCu, and Al <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> Cu thin films have been investigated as potential alternatives for Cu in interconnect metallization schemes. Stoichiometric NiAl thin films of 56 nm thickness show a resistivity of 13.9 μΩ cm after post-deposition annealing at 600°C. Different capping layers were tested to overcome the formation of an oxide top layer. Al <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Sc presents a resistivity of 12.5 μΩ cm after post-deposition annealing at 500°C (for 24 nm thick films). AlCu and Al <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> Cu outperform Ru films at 20 nm thickness and above (9.5 μΩ cm for 28 nm films). Challenges and integration feasibility are discussed.