Bromine ions react with the aluminum in the gold-aluminum intermetallic phase to form AlBr3 and precipitate gold. The aluminum bromide then hydrolyses to Al2O3, reliberating the bromine so that it may continue the corrosion cycle. Corrosion changes the chemical makeup of the bond and can therefore lead to resistance changes that range from minor to catastrophic. Corrosion of the bond pad will lead to lower conductivity due to the formation of resistive compounds at the interface. Broken wires may also be induced, leading to shorts or opens.
Electrical noise can also be a byproduct of corrosion.