Study of a single layer ultrathin CoMo film as a direct plateable adhesion/barrier layer for next generation interconnect

In this work, a novel single layer CoMo alloy film is investigated as an excellent adhesion/diffusion barrier to copper metallization. The ultrathin (<;3nm) CoMo film can withstand 400°C/30min annealing on the ULK(k =2.25) and the electrical barrier properties on the p-cap SiO2 structure for the Cu/CoMo can be even better than the Cu/Ta/TaN structure. The CMP of the CoMo film are studied and the direct Cu electroplating on the CoMo film are demonstrated.