Influence of carbon nanotubes on the electrodeposition of copper interconnects

The electrochemistry of the co-deposition of Cu with carbon nanotubes, CNTs, is studied by voltammetry and chronoamperometry experiments. Electrochemical data show that CNTs have a slightly accelerating influence on the Cu electrodeposition when nafion was added in the bath as a surfactant of CNTs. The amount of CNTs in the deposit is up to 2% by weight. Kinetic data confirm that the addition of CNTs to the Cu baths increases the Cu exchange current density and decreases the equilibrium potential value. The electrical resistivity results show that at room temperature the resistivity of a Cu/CNT composite film (2.47 μΩ·cm) is close to the resistivity of Cu film (2.15 μΩ·cm). A clear decrease of sample resistivity is observed with increasing anneal temperature up to 315°C The resistivity also increases when die concentration of CNTs is increased from 10 mg/l to 100 mg/l in the bath.