Investigation of RuZn alloy as barrier to Cu interconnect

Ru is an excellent adhesion layer to copper and possible conductor material yet it has poor barrier properties and poor adhesion with SiO 2 . In this work, a novel self-formed barrier, RuZn with around 0.3 at.% Zn has been prepared by sputtering and following annealing. Its adhesion property with SiO 2 and thermal stability are much improved. A very high average value of 42.42 J/m 2 for the interface fracture energy between RuZn and SiO 2 can be obtained through an improved four-point bending method. Results show that during the annealing, Zn from the RuZn migrates to the Ru/SiO 2 interface and Zn 2 SiO 4 forms at the Ru/SiO 2 interface, which inhibits the diffusion of Cu as well as improves the adhesion.