Moisture ingression in plastic packages essentially occurs through delaminated interfaces. Hence, package reliability depends on the interfacial integrity between the various materials. In the present work, the adhesion of epoxy-based molding compound and the copper leadframe is discussed. Results show that by the growth of a copper oxide layer, the surface roughness improves which promotes interlocking between the molding compound and leadframe during mold packing stage. Also by controlling the oxide thickness with pore-free structure, the adhesion strength can be significantly improved. (c) 2005 Elsevier B.V All rights reserved.