AN X-RAY STUDY ON THE MECHANICAL EFFECTS OF THE PEEL TEST IN A CU CR/POLYIMIDE SYSTEM/

In order to understand the effects of plastic deformation and the inte rfacial fracture energy on the peel strength, thickness of the metal l ayer and the pretreatment conditions of polyimide were varied in the C u/Cr polyimide system. The work expenditure during the peel test was e stimated using the stress-strain curves of metal films, X-ray measurem ents of the plastic strain in peeled films, and the elastoplastic beam analysis. Results indicate that the peel strength is strongly affecte d by the film thickness and the pretreatment condition in a synergisti c way, and that the peel strength shows a maximum at an intermediate t hickness level. The estimated work expenditure was close to measured p eel strength for most of the cases, which indicates that the measured peel strength is more a measure of the plastic deformation during the peel test than a measure of the true interfacial fracture energy. (C) 1997 Acta Metallurgica Inc.