Effects of the TiN diffusion barrier and post‑annealing between Ru and SiO2 films on the interfacial adhesion energy for advanced interconnections

This study investigated the effects of the atomic layer deposited (ALD) TiN diffusion barrier and post-annealing on the interfacial adhesion energy between the ALD Ru and SiO2 films using a four-point bending test. The interfacial adhesion energy of the Ru/SiO2 structure without the TiN diffusion barrier was as low as 3.20 J m−2, and it increased to 10.10 J m−2 with the TiN diffusion barrier between the Ru and SiO2 films. After post-annealing at 400 °C for 100 h, the interfacial adhesion energies of the Ru/SiO2 and Ru/TiN/SiO2 structures increased to 7.16 and 25.26 J m−2, respectively. X-ray photoelectron spectroscopy analysis revealed that the interfacial adhesion energy of Ru/TiN/SiO2 thin films increased due to the formation of a TiN x O y reaction layer at the TiN/SiO2 interface. After post-annealing at 400 °C, the interfacial adhesion energy further increased, which is attributed to the formation of RuSiO x bonds at the Ru/SiO2 interface and TiO2 bonds at the TiN/SiO2 interface.