Surface cleaning method for elimination of Cu-oxide layer formed on Cu film

摘要

We investigated the effects of surface cleaning to eliminate the surface native oxide on Cu film. The Cu seed layer was deposited on Ti/p-Si (100) by sputter deposition. NH4OH and H2SO4 solutions after TS-40A pretreatment were used to remove the Cu-oxide, and then the changed surface of Cu film was estimated by AFM, SEM, and XPS. By H2SO4 treatment after TS-40A pretreatment, the Cu-oxides on surface of Cu seed film [including CuO, Cu(OH)2, and CuCO3 contaminants] were eliminated uniformly. However, by NH4OH treatment after TS-40A pretreatment numerous large and small etch pits formed and the RMS roughness of Cu film surface was larger. Consequently, we found that H2SO4 cleaning after TS-40A pretreatment is very effective at Cu-oxide removal.