Journal of the Microelectronics and Packaging Society

The quantitative interfacial adhesion energies of transition metal nitride materials were evaluated using the double cantilever beam method for advanced Ru interconnect applications, and the delaminated surfaces were analyzed to identify the failure locus. When TiN and MoN were applied as diffusion barrier layers, the interfacial adhesion energy was 1.42 ± 0.27 and 3.53 ± 0.61 J/m² , respectively. This indicates that the MoN exhibited approximately 1.5 times higher adhesion than TiN. The X-ray photoelectron spectroscopy results confirmed that both samples exhibited delamination between the diffusion barrier and the SiO₂ interface. This suggests that the higher interfacial adhesion energy observed in the MoN sample is attributed to the lower mismatch in coefficient of thermal expansion with SiO₂, resulting in reduced residual stress during film deposition and thermal processing. In addition, the higher oxidation activation energy of MoN compared to TiN leads to the formation of a more stable oxide, thereby contributing to its higher interfacial adhesion energy.

Keywords Ru interconnect, Transition metal nitride, Diffusion barrier, Atomic layer deposition, Interfacial adhesion energy, Double cantilever beam