Stress-induced voids in Ni-Pt silicide: Disconnection of narrow (Ni-Pt)Si between gate canyons on wide active area

Stress-induced voids (SIVs) in Ni-Pt silicide have been discovered at the six sigma level. These voids led to disconnection of the silicide between gate canyons caused by tensile stress loaded from a shallow trench isolation (STI) structure. The SIVs were suppressed by forming a mono-silicide at the second silicidation annealing. This is possible because Ni migration did not occur under the thermal budget of interconnect fabrication. Therefore, the defect density of 8-Mbit static random access memory of 45-nm-node was improved.