The electrochemical migration (ECM) behavior of Electroless Nickel Immersion Gold
(ENIG) surface finish was studied using Na2SO4 solutions with various concentrations.
The investigations were carried out by water drop (WD) test. During WD test the electrochemical
processes were followed by electrical and visual inspections. Based on the mean-time-to-failure
(MTTF) data it was shown that MTTF increased at 0.1 mM Na2SO4 solution, then on higher
concentrations MTTF significantly decreased and stabilized over the concentrations.
