Adhesion of a novel flexible epoxy molding compound and its molecular dynamics simulation

To improve the flexibility and adhesion of epoxy molding compound (EMC), a flexibilizer named 1,3-propanediol bis (4-aminobenzoate) (PBA) was added in an EMC product to prepare a flexible EMC. Because of PBA in EMC, the reduction of storage modulus and lowered glass transition temperatures would be very great helpful to reduce thermal stress build-up during high temperature soldering process. With the increase of PBA, the variation trends of tab pull force of copper and silver plated lead frame within EMC increased accordingly, the increments were up to 58% and 117%, respectively. From the molecular dynamics simulation on interfacial bonding energies between EMC and lead frames, the interfacial bonding energy was 2.09 J m−2 and 1.89 J m−2 for epoxy molecules with Cu2O and Ag2O, respectively, that meant the interfacial bonding energy of copper plated lead frame within EMC was greater than silver plated lead frame within EMC.