Study of EMC for Cu bonding wire application

The influence of EMC (Epoxy Molding Compound) and reliability with fine Cu wire was studied. It is found that the failure mode was corrosion at the intermetallic layer of the wire bonding part by failure analysis after HAST (Highly Accelerated Temperature & Humidity Stress Test). Al elution and Cl ion was observed at the intermetallic layer. EMC with lower Cl ion content and Al inhibitor of corrosion shows better HAST property. The selection of flame retardant for green EMC is important because some retardant has a negative impact on HAST performance.