A novel NiSi technology with bi-layer Co/TiN structure as a capping layer is proposed for the highly thermal immune Ni Silicide technology. Much better thermal immunity of Ni Silicide was certified up to 700, 30 min post silicidation furnace annealing by introducing Co/TiN bi-layer capping. The proposed structure is successfully applied to nano-scale CMOSFET with a gate length of 80 nm. The sheet resistance of nano-scale gate poly shows little degradation even after the high temperature furnace annealing of 650, 30 min. The Ni/Co/TiN structure is very promising for the nano-scale MOSFET technology which needs the ultra shallow junction and high temperature post silicidation processes