Importance of PCBA cleanliness in humidity interaction with electronics

Probability of Failure due to Electrochemical Migration on Surface Mount Capacitor under Electrolyte Condition with same Contamination and Conductivity Level

“…The soldering process, especially wave soldering because of the use of liquid flux by spraying process, introduces ionic residues on the PCBA surface during the manufacturing process, which along with other factors, affects the corrosion failures related to humidity on the PCB surface [6], [7]. Most of the no-clean flux systems today are based on weak organic acid (WOA) activators [8]. Typically, these acids can be adipic, succinic, and glutaric, to name a few, which are hygroscopic similar to sodium chloride (NaCl).…”

Humidity in Power Converters of Wind Turbines—Field Conditions and Their Relation with Failures

“…However, comprehensive field-experience based research of the Fraunhofer Institute for Wind Energy Systems IWES, Germany, using failure data from thousands of wind turbines (WT) around the world in combination with post-mortem analysis of field-returned converter components revealed that the above fatigue effects are not among the prevailing causes of the converter failures observed in today's wind turbines [4][5][6]. Instead, the observed strong seasonal clustering of failures points to climatic influences, in particular to humidity, as a Energies 2021, 14,1919 2 of 27 relevant stressor and likely cause of converter failure [4,6]. Wind-power specific results of other research groups confirm the relevance of humidity in the context of converter failure: based on data from an older WT fleet, Tavner et al [7] revealed a clear correlation between WT failures and weather conditions, with temperature and humidity having an even more significant effect than wind speed.…”

“…This is indicated by publications such as [10][11][12], but also by the numerous contributions and strong industrial interest in a recent workshop of the European Center for Power Electronics (ECPE) on this subject [13]. In general, the trend towards miniaturization and higher component density in electronics increases their susceptibility to humidity, as pointed out in [14,15]. This is due to (1) higher packaging densities coming along with reduced distances of components and conducting tracks that facilitate a bridging, e.g., by water droplets or growing filaments; (2) higher electrical field strengths being a key driver for migration and corrosion effects; and (3) lower heat generation and with that reduced self-heating.…”