Electrochemical migration of Nickel and Electroless Nickel Immersion Gold surface finishes during Thermal Humidity Bias test
The electrochemical migration (ECM) mechanism occurs at the presence of moisture in the case of operating circuits and resulted in shorts (dendrites) between adjacent conductor traces. Dendrite growth occurs as a result of metal ions being dissolved into a solution from the anode and deposited at the cathode, thereby growing in tree like formations. In this study the water condensation process and ECM behavior of Ni, Electroless Nickel Immersion Gold (ENIG) and Cu (as reference) was investigated using Thermal Humidity Bias (THB) test. Preliminary results shows that Ni and ENIG surface finishes have lower MTTF values than Cu.