Adhesion behavior between epoxy molding compound and different leadframes in plastic packaging

Adhesion has been identified as one of the key elements in solving failure problems in electronic packaging. Understanding and improving the adhesion between epoxy molding compound (EMC) and leadframes is thought to be a key step towards improving package performance. The objective of this work was to study the effect on adhesion behavior and delamination of plastic packages using various metal coated leadframes that had been subjected to preconditions. In this work, the effects of moisture absorption testing and reflow process on the interface adhesion strength of the EMC/metal leadframes were studied. Three kinds of metal coated leadframes were used: copper, silver coated copper and nickel/palladium/gold coated copper. Adhesion strength was measured using the tab pull test. These data were correlated to some extent with the findings of package delamination observed by the C-mode Scanning Acoustic Microscope (C-SAM). Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) were employed to characterize the surface of EMC and metal leadframes after separation along the vertical plane.