Buckle delamination on patterned substrates

Abstract

Lithographic techniques applied to a substrate prior to film deposition can create areas of low interface adhesion surrounded by regions of high adhesion. If the film is under compression and if buckle delamination is nucleated, conditions can be controlled such that delaminations are confined to the patterned areas of low adhesion. When the area of low adhesion is a strip, the width of the strip controls the buckle morphology: smooth Euler buckles for narrow strips, asymmetric telephone cord buckles for wider strips, and symmetric varicose buckles under a very limited range of conditions. Results for the elastic energy in the buckled state show that above a critical stress the telephone cord morphology is the preferred morphology. Energy release rates for propagating delaminations are determined for each of the three morphologies. Tapered strips provide an accurate means of measuring interface adhesion based on the width of the strip where the delamination arrests.