Degradation of moulding compounds during highly accelerated stress tests - A simple approach to study adhesion by performing button shear tests

High temperature storage can degrade moulding compounds for chip encapsulation to such an extent that the adhesion to surfaces like copper (lead frames) or polyimide (chip coating) decreases drastically causing delamination. Also during normal operation of electronic components heat is generated locally (bond wire or chip surface) degrading the moulding compound and reducing the adhesion which in extreme cases can destroy the metallisation or the bond wires.