The effects of ion beam treatment on the interfacial adhesion of Cu/polyimide system

Abstract

In microelectronics packaging, the reliability of the metal/polymer interface is an important issue, as the adhesion strength between dissimilar materials is often inherently poor. The modification of polymer surfaces using Ar ion beam irradiation and RF plasma deposition has been commonly used to enhance the adhesion strength of the interface. In this study, the treatment of polyimide surfaces with Ar or O2 ion beam irradiation and the DC magnetron sputtering of Cu films were adopted to prepare the specimens of Cu/polyimide systems. The results indicate that the peel strength increases as the Ar or O2 ion beam irradiation energy increases at a fixed metal-layer thickness. Additionally, the treatment of polyimide surfaces using O2 ion beam irradiation showed a higher peel strength than if Ar ion beam irradiation was utilized. This increase in peel strength mainly results from an increase in the surface roughness as well as an increase in the functional group on the polyimide film, both caused by ion beam irradiation.