Thermodynamic evaluation of the liner and barrier properties of a single-phase interlayer for advanced Cu interconnections

Cu interconnection would face rapid increase in resistivity due to the thick double layer of Ta/TaN. In this paper, we propose a single interlayer having dual function of liner and barrier to replace Ta/TaN. Thermodynamic simulation was employed to explore suitable interlayer materials. Key parameters for material selections included T
0
curve, Cu immiscibility with the interlayer, and interface reaction between the interlayer and SiO
2
. The results confirmed Co–Zr and Co–Ti alloys to be potential candidates for the interlayer as experimentally reported in our previous work.