Aluminide intermetallics for advanced interconnect metallization: thin film studies

AlNi, Al
3
Sc, AlCu, and Al
2
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
3
Sc presents a resistivity of 12.5 μΩ cm after post-deposition annealing at 500°C (for 24 nm thick films). AlCu and Al
2
Cu outperform Ru films at 20 nm thickness and above (9.5 μΩ cm for 28 nm films). Challenges and integration feasibility are discussed.