Effects of mechanical properties of metal films on thf adhesion strength of Cr/polyimide interfaces

Abstract

Effects of mechanical properties of Cu/Cr metal films on the peel strength of Cr/PI interfaces have been studied. Or and Cu thin films were successively sputter-deposited on in-situ RT; plasma-treated polyimides, and 20 mu m-thick Cu was electroplated. With increasing the yield strength of Cu/Cr films from 156 MPa to 325 MPa, peel strength of Cr/FMDA-ODA and Cr/BPDA-PDA were lowered from 75 g/mm to 57 g/mm and from 69 g/mm to 20 g/mm, respectively. With identical Cu/Cr metal films, lower peel strength was obtained on Cr/BPDA-PDA interfaces, compared to the values of Cr/PMDA-ODA. Peel strength was also decreased more pronouncedly on Cr/BPDA-PDA with increasing the yield strength of Cu/Cr metal films. With T/H (80 degrees C/94% R.H.) exposure, however, peel strength was lowered much more pronouncedly on Cr/PMDA-ODA than on Cr/BPDA-PDA, especially for specimens with Cu/Cr metal films of lower yield strength.