Al2O3-Coated Bonding Wire with Electrical Insulation & Promoted Adhesion

Conventional bond wires composed of Au, Ag, & Cu don’t meet market demands for strong adhesion, electrical insulation, and corrosion passivation due to their conductive metallic surfaces. We propose a solution through the applications of a ceramic (Al2O3) coating at nanometer scales on these metal wires, thereby improving their adhesion to encapsulation, electrical insulation, and resistance to corrosion. We used ALD (Atomic Layer Deposition) methods to coat Au and Ag metal wires with diameters ranging from 18um to 48um (0.7mil~1.9mil) with Al2O3. Our paper details the innovative processes we used to incubate the idea of Al2O3 coating on conventional bond wires, focusing on wire bondability and dependability. Our findings demonstrate enhanced electrical insulation between crossing wires and increased reliability related to the wires’ adhesion to encapsulation.