Adhesion improvement of Epoxy Molding Compound – Pd Preplated leadframe interface using shaped nickel layers

The weak adhesion between the Epoxy Molding Compound (EMC) and Pd Preplated leadframes (Pd PPF’s) often causes delaminations and reduces the reliability of integrated circuit. This paper reports on a practical method of dramatically improving the adhesion between EMC and Pd PPF’s using electroplating of shaped nickel layers. Button shear tests indicate that the adhesions between the EMC and three different shaped PPF’s are 100%, 160%, 169% higher than that of conventional PPF’s. The mechanical interlocking effect caused by increased surface roughness is the major reason for the improved adhesion as well as for the failure mode transition from adhesive failure to cohesive failure.

► 3 shaped PPF electroplated.
► EMC–PPF adhesion improved by 169%.
► Interlocking caused the improvement.
► Adhesive failure changed to cohesive.