Heterointerfacial adhesion failure mechanism of ultrahigh filler loading containing epoxy composite films for chip substrates

Abstract

High adhesion force of chip substrates is crucial for improving chip reliability in the field of microelectronics. However, the flip chip ball grid array (FCBGA) substrate has faced a huge challenge in that the adhesion mechanism of epoxy composite film/copper is not clear so far. Herein, epoxy resin composite film, copper and core board are used to fabricate FCBGA substrates by the lamination method, and then two kinds of FCBGA substrates were obtained based on epoxy–cyanate ester/silica composite and epoxy–phenolic/silica composite films. Their adhesion behavior and mechanism were analyzed by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), contact angle measurement and interference microscopy. It is demonstrated that compared with the epoxy–phenolic/silica composite, the ultrahigh filler loading containing epoxy–cyanate ester/silica composite film has a lower adhesion strength, which is mainly attributed to weak mechanical anchoring, low work of adhesion and low bonding force in chemistry as well as high copper oxides at the heterointerfacial areas. This work will provide a guidance in theory and experiment to enhance the interfacial adhesion force of epoxy resin composite films for advanced chip substrates in the future.