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

Abstract 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 SiO 2 films using a four-point bending test. The interfacial adhesion energy of the Ru/SiO 2 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 SiO 2 films. After post-annealing at 400 °C for 100 h, the interfacial adhesion energies of the Ru/SiO 2 and Ru/TiN/SiO 2 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/SiO 2 thin films increased due to the formation of a TiN x O y reaction layer at the TiN/SiO 2 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/SiO 2 interface and TiO 2 bonds at the TiN/SiO 2 interface.