Conformal Coating Characterization Using Stacked Silver Thin Films

Data center proliferation continues unabated consuming ever-increasing amounts of energy. The rising energy-associated computing costs can be somewhat contained by cost cutting measures such as not tightly controlling the temperature and humidity levels in data centers and in many cases resorting to airside economizers and direct evaporative air cooling, but as a result, exposing hardware to the associated risk of reliability degradation from particulate and gaseous contamination entering data centers. Conformal coating is a proven means of physically protecting electronic hardware so that it can operate reliably in polluted and humid environments. There are two obvious ways of testing the performance of conformal coatings. One is the conventional approach based on determining the mean time to failure of coated hardware exposed to a corrosive environment. The other method, that is the subject of this paper, is based on conformally coating metal thin films and measuring their corrosion rates in a corrosion environment. A convenient corrosive environment is a flowers of sulfur chamber. In this paper, the performance of conformal coatings was determined, via this second approach, as a function of temperature under very low and relatively constant humidity condition. The results were compared to those from the convention approach involving coating the actual hardware. The activation energies of metal thin film corrosion and diffusion of the corrodents through the conformal coatings will also be reported.