Electromigration evaluation of aluminum alloys in multilevel metallization

Abstract This paper focuses on Ti / Al −2.0% Si −0.5% Cu and Ti sandwiched Al−0.5%Cu metallurgies. The electrical reliability of the two Al alloys was determined by a standard electromigration technique (elevated d.c. current and temperature) utilizing single-level and two-level interconnect structures. Transmission electron microscopy and scanning electron microscopy have been used to characterize the film microstructure formed during processing and the types of failure modes observed electrically. For a linewidth approximating film thickness, the formation of a bamboo microstructure dominated the t 50 data. TACT films provided superior performance for a stripe linewidth of 2.7 μm and a maximum chain-link length of 100 μm. The common failure modes of the different metallurgies were described, with the TACT exhibiting extrusion.