Study of CVD Cu/IMP Cu/TaN/SiO2/Si Structures

摘要

We report the properties of the copper films deposited by metal-organic chemical vapour deposition (MOCVD) and the interaction between the copper film and its neighbour layers in the Cu/TaN/SiO_2/Si structures upon annealing in a furnace in a nitrogen environment. It is found that the sheet resistance of the copper film slightly decreases as the annealing temperature increases upto 500 ℃ and then increases drastically with the further increase of the annealing temperature. From x-ray diffraction, both CuTa_(10)O_(26) <200> and TaSi_2 can be observed in the MOCVD Cu/ TaN/SiO_2/Si structures at an annealing temperature of 600 ℃, indicating an interaction between the Cu film and the layer underneath. For the structures which have a deposited flash Cu layer between the CVD Cu film and TaN barrier, however, the TaSi_2 cannot be observed. SIMS analysis indicates that the addition of the flash Cu layer also impacts Cu diffusion across the barrier metal due likely to the change in the crystallographic plane of the Cu films.