Ta-based barrier layer improved by plasma immersion ion implantation

Ta and TaN have been proved to be effective barrier layer materials in copper interconnection. Carbon is implanted into 25nm Ta and TaN films with different doses by Plasma Immersion Ion Implantation (PHI). After annealed under 700°C for half an hour, a Secondary Ion Mass Spectrometer (SIMS) study shows that, the performance of implanted Ta-based barrier layer is much better than before implanted. Transmission Electron Microscopy (TEM) investigates the microstructure of samples. Mechanism of this effect is discussed based on detailed comparison between samples with and without PIII. The author would like to acknowledge the contribution of Institute of Microelectronics of Singapore who prepares the nano-scale Ta based thin film. And PHI processing is supported by Plasma Laboratory, Department of Physics and Materials Science, City University of Hong Kong.