Environmental effects on interfacial adhesion

The effects of temperature and moisture on the reliability of interfaces commonly found in thin-film interconnect structures were investigated. Debond growth rate vs. debond driving energy curves (V-G curves) were collected over a range of environmental conditions for both metal/SiO2 and polymer/SiO2 interfaces. For the metal/SiO2 system, the V-G curves were found to be relatively insensitive to increases in temperature over the range of 0 - 85 degreesC but strongly influenced by the moisture content in the surrounding environment. The exact behavior in the metal/SiO2 system depended on the debond path and the structure of the thin film stack. The controlling mechanism for debond advance was found to change as the overall stack structure was altered. The polymer/SiO2 system was found to show the same sensitivity to moisture as the metal/SiO2 system indicating a similar mechanism was leading to debond advance. The mechanisms identified in both systems are explained in terms of the salient chemical reactions occurring at the debond tip. The relationship between the work of adhesion, or bond breaking process, and the macroscopic work of fracture, which includes non-linear energy absorbing processes such as plasticity, was explored. (C) 2001 Elsevier Science Ltd. All rights reserved.