Design of aluminum/polyimide stretchable interconnects investigated through in-situ testing

In this paper, the mechanics of Aluminum/Polyimide stretchable interconnects is investigated in relation to the structural design of the metal conductor. In-situ electron- and laser-scanning microscopy are combined with mechanical testing to perform both morphological and topographical analysis of failure mechanisms at the small scale. An interplay between interface delamination and metal film buckling is observed and connected to the mismatch between the kinematics of the polymer substrate and the meandering metal film. The role of the metal/polymer interface as a constraint to negotiate the aforementioned kinematics mismatch is discussed, suggesting the relevance of interface mechanics characterization in the view of reliable meander design.