Post Salicidation Clean: Removal of Unreacted Pt from High Pt Content NiPt Silicide

Silicides are used for providing stable ohmic contacts on gate, source and drain areas. After the silicide is formed, unreacted silicide is removed by using strongly oxidizing wet clean solutions. For 2x nm technologies, Ni Pt has been used as a salicide with progressively higher amounts of Pt used for each advanced node. Complete removal of unreacted Ni Pt was found to have become became intermittent when the Pt content in the silicide exceeded 10%. The residual unreacted Ni Pt stringers were found to be pure Pt. A wet clean process was developed to remove unreacted Pt in all cases and its manufacturability determined for a semiconductor high volume manufacturing production line.