Electrochemical migration and dendrite growth between two electrodes: Experiments and Brownian dynamics simulations

Electrochemical migration (ECM) is a common cause of failure in printed circuit boards (PCB) due to dendrite growth between exposed metallic conductors under moisture especially in the presence of flux residues. Understanding this phenomenon, therefore, is of interest from technological and economical points of view. Here, we report experimental results of water drop tests on surfaces contaminated by various amount of flux residues, which are supplemented with Brownian dynamics (BD) results to gain molecular insight into ECM and dendrite growth. BD is a particle simulation method where the ions are modeled explicitly. We show dendrite growth curves (the length of the longest dendrite as a function of time) obtained from visual examination with digital video microscope and from BD simulations. Results for the time to failure are also shown for various values of the electric field strength and cation (Sn 2 + ) concentration (dilution of contamination). We report a mapping of experimental and simulation results that is necessary due to the large concentrations and electric field strengths used in the BD simulations. • Experimental results of water drop tests on printed circuit board surfaces contaminated by various amount of flux residues are reported. • They are supplemented by Brownian dynamics simulations results. • Dendrite growth curves and results for time to failure are reported. • A procedure to map experimental data into simulation results is reported.