Impact of low-k moisture absorption during queue-time on Cu-alloy/low-k reliability and its suppression

The moisture absorption impacts on electromigration (EM) and time-dependent dielectric breakdown (TDDB) were investigated in Cu alloy/low-k interconnects. A long queue time (Q-time) has a serious impact on kinetics of both EM and TDDB characteristics. The moisture absorption causes the loss of alloy effects on EM lifetime improvements. The ultra-thin SiN (UT-SiN) remarkably suppresses the moisture absorption impacts due to Q-time. It also improves kinetics degradations of EM and TDDB that depend on the moisture absorption to low-k.