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 T0 curve, Cu immiscibility with the interlayer, and interface reaction between the interlayer and SiO2. The results confirmed Co–Zr and Co–Ti alloys to be potential candidates for the interlayer as experimentally reported in our previous work.