The influence of liners with Ti, Ta or Ru finish on thin Cu films

The influence of the different liner material stacks Ti-N/Ti, Ta-N/Ta and Ta-N/Ru on the microstructure of 1 μm thick sputtered Cu films is examined prior to and after annealing. It is shown that the liner has an impact on the crystallographic orientation distribution of the Cu grains and seriously affects the defect density in the Cu films. The measured Cu resistivity shows a strong dependence on the microstrain.