Advantage of Siconi¿ Preclean over Wet Clean for Pre Salicide Applications Beyond 65nm Node

For advanced devices at 65 nm node and beyond, nickel silicide formed by depositing Ni or its alloys with subsequent annealing has been chosen as the source/drain and gate contact materials. An in-situ dry chemical cleaning technology (Siconi ) has been developed to be integrated with PVD nickel deposition, thus forming a defect-free silicide/Si interface. Queue time related surface contamination and defects caused by using wet (HF) chemical cleaning are thus eliminated. The dry and wet etch methods are compared in this paper in terms of the film Rs, microstructure and thermal stability, as well as the line width effects measured on test wafers.