Process optimization to reduce NiSi pipes and NiSi agglomeration on 28nm Nickel silicide LSA ms anneal process

NiSi pipes are formed on SiGe during conventional (He based) RTA anneal processes in NiSi module due to Ni diffusion. NiSi pipes increase leakage and reduce device Vt's. The control of Nickel diffusion is essential for device control. In this paper we use a laser anneal tool at NiSi RTA2 to control Ni diffusion. The formation of NiSi-pipes is studied as a response of process factors, such as laser and chuck temperature, wafer rotation, and dwell time. The high process temperature in the range of 700–950°C can melt NiSi. The onset of NiSi melting as a function of process parameters and layout locations are studied.