The behavior of TiN and Ti barrier metals in Al-barrier-Al via structures was investigated. When a reactive-sputtered TiN film is deposited onto an Al-1 weight percent (w/o) Si-0.5 w/o Cu surface, AlN is formed at the TiN/Al interface due to the reaction of N2 to Al, and causes an increase in via contact resistance. To suppress the increase in via contact resistance, it is crucial to interpose a Ti buffer layer at the TiN/Al interface. The via contact resistance of the Al/TiN/Ti/Al structure increases at annealing temperatures over 450-degrees-C, since AlN is formed at both the Al/TiN and TiN/Ti/Al interfaces. The Al/TiAl via contact structure presents a specific low resistance after annealing above 450-degrees-C, Al3Ti is formed at both the Al/Ti and Ti/Al interfaces. Further, the Al3Ti layer can improve the electromigration performance of the interconnection which consists of a TiN/Ti/Al structure. The electromigration performance for various via structures also was investigated. Al/Ti/Al and Al/TiN/Ti/Al via contact structures tend to increase the chain resistance before via open failure, where the dominant mechanism is the void formation originating from the migration of Al atoms in the vias rather than the via lift-off mode. This means that Al atoms migrate easier on a TiN layer than on a Ti layer. As a result, an Al/Ti/Al via structure is better for electromigration performance.