Optimization of NH3 plasma surface treatment using Cu silicide formation for EM/SM improvement

Authors investigated optimization of NH₃ plasma surface pre-clean treatment using Cu silicide formation in order to improve electromigration (EM) and stressmigration (SM). NH₃ plasma treatment removed Cu oxide but also led to reduced Cu silicide at the Cu/capping layer interface. Despite Cu oxide removal, EM/SM was observed to degrade due to the reduction of Cu silicide. It was critical to restore Cu silicide at the interface when employing NH₃ plasma treatment to improve EM/SM.