Adhesion strength of leadframe/EMC interfaces

Abstract

Cu-based leadframe sheets were oxidized in alkaline solutions to produce brown and/or black oxide on the surfaces, and molded with epoxy molding compound (EMC). The adhesion strength of leadframe/EMC interface was measured using sandwiched double-cantilever beam (SDCB) specimens and pull-out specimens. Results showed that the adhesion strength of leadframe/EMC interface was inherently very poor but could be increased drastically with the nucleation of acicular CuO precipitates. The presence of smooth-faceted Cu(2)O on the surface of the leadframe gave close to zero fracture toughness (G(C)) and suitable pull strength (PS). A direct correlation between G(C) and PS showed that PS can be a measure of G(C) only in a limited range.