Environmentally assisted debonding of copper/barrier interfaces

Environmentally assisted debonding at Cu/barrier interfaces is reported for oxidizing and reducing environments. Both moist and dry oxidizing environments are considered, and the effects of different oxidizing species and their chemical activity on the rate of debonding of a Cu/SiN interface is quantified. The type of oxidizing species is shown to play a critical role in the kinetics of environmentally assisted debonding. Additionally, the effect of varying the activity and temperature of reducing hydrogen environments is investigated. The mechanisms responsible for environmentally assisted debonding of Cu/SiN and Cu/SiCN interfaces are elucidated using an atomistic bond rupture model. An activation energy for debonding of Cu/SiCN interfaces in a hydrogen environment is calculated. Finally, a connection between environmentally assisted debonding and the time-dependent dielectric breakdown properties of Cu interconnects is proposed. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.