Subcritical Debonding of Multilayer Interconnect Structures: Temperature and Humidity Effects

Thin film structures may fail by progressive or time-dependent debonding at stresses far below those required for catastrophic failure. Previous work has shown that progressive debonding in a typical interconnect structure occurs either along the TiN/SiO 2 interface or parallel to this interface in the SiO 2 Such subcritical debonding was found to span several orders of magnitude of debond growth rates and occur at significantly reduced driving forces. The presence of SiO 2 at the failure location indicates that the mechanisms which give rise to stress corrosion cracking in bulk glasses may also play a role in the subcritical debonding behavior of multilayer interconnect structures. Accordingly, this work focuses on the effects of temperature and humidity on subcritical debonding and rationalizes them in terms of the relevant chemical reactions taking place at the debond tip.