Wire bonding of Au-coated Ag wire: Bondwire properties, bondability and IMCs formation

We recently developed cost effective and highly stable bond wire and more corrosion-resistant than that of conventional Ag base wire. An efficient and environmental-friendly method, featuring a non-cyanide Au plating process was made for Au-coated Ag wire. Therefore, it can serve as feasible Au or PCC wires alternatives for the next generation. ACA wire has several advantages including excellent conductivity. This new Ag wire can meet reliability standards of wire bonding. The proposed ACA wire was studied to ensure compatibility with electrical properties; characterization of IMCs. The results show that electrical properties at high temperature manifest that the ACA wire maintains superior electrical resistance. Interfacial IMC grew Ag2Al and AuAl2 from Ag-Au ball and Al pad after aging for 500h at 175 degrees C. ACA wire formed by the non-cyanide plating method has wide application prospects in IC packaging processes.