Thiol-based self-assembly nanostructures in promoting interfacial adhesion for copper-epoxy joint

Adhesion promotion between copper-epoxy interfaces without roughening the copper substrates is critical for new generation electronic devices. This paper demonstrates a pronounced adhesion promotion of a copper-epoxy joint from 4.8 J m−2 for the untreated samples to 159 J m−2 for the interfaces prepared with a thiol-based self-assembly molecular layer (SAM). The 33-fold improvement was related to the presence of nanostructures with the SAM treatment. The adhesion enhancement is attributed to both chemical bonding between copper and epoxy and the formation of nanosized features on copper substrates. The thiol promoter enhances the interfacial adhesion with no roughening of the substrates.