Investigation of amorphous RuMoC alloy films as a seedless diffusion barrier for Cu/p-SiOC:H ultralow-k dielectric integration

Ultrathin RuMoC amorphous films prepared by magnetron co-sputtering with Ru and MoC targets in a sandwiched scheme Si/ p -SiOC:H/RuMoC/Cu were investigated as barrier in copper metallization. The evolution of final microstructure of RuMoC alloy films show sensitive correlation with the content of doped Mo and C elements and can be easily controlled by adjusting the sputtering power of the MoC target. There was no signal of interdiffusion between the Cu and SiOC:H layer in the sample of Cu/RuMoC/ p -SiOC:H/Si, even annealing up to 500 °C. Very weak signal of oxygen have been confirmed in the RuMoC barrier layer both as-deposited and after being annealed, and a good performance on preventing oxygen diffusion has been proved. Leakage current and resistivity evaluations also reveal the excellent thermal reliability of this Si/ p -SiOC:H/RuMoC/Cu film stack at the temperatures up to 500 °C, indicating its potential application in the advanced barrierless Cu metallization.