Selective Nickel Platinum Removal without Titanium Nitride Metal Gate Corrosion

During silicide formation, unreacted NiPt metals is traditionally removed either by aqua regia (ESH concern) or SPM. This latter can easily degrade the device yield in HKMG (High K Metal Gate) nodes if the metal gates (usually TiN based) aren’t perfectly encapsulated. First some new characterizations are presented to better understand the NiPt metal alloy removal, then a new solution is given to be able to remove this alloy without degrading HKMG materials.