The influence of Si in Al-0.5 mass%Cu-1 mass%Si alloy layered with TiW on the electromigration resistance and the interfacial reaction has been investigated using 0.3 and 0.5 µm wide test patterns.
It is found that Si in Al-Cu-Si alloy promotes interfacial reaction of above bilayer systems during annealing at 723 K. Intermetallics of W(Al, Si)2, WAl5 and WAl12 are formed during annealing. It is also found that these intermetallics increase resistance and deteriorate electromigration resistance of bilayered interconnections. Al-0.5 mass%Cu/TiW has slightly better electromigration resistance than Al-0.5 mass%Cu-1 mass%Si/TiW.
(Received November 11, 1991)
electromigration, LSI, interconnection, Al-Cu-Si/TiW, intermetallic compound submicronlinewidth, silicon precipitation, sintering, contact spiking, bamboo-structure