Failure analysis of printed circuit boards in the main telephone system of marine product factory

摘要

The failure of themain telephone systemin amarine product factory due to copper sulfide (Cu2S) creep was analyzed by themeasurement of hydrogen sulfide (H2S) in the atmosphere, elemental analysis with energy dispersive X-ray spectroscopy, and cross-sectional observation of vias in the printed circuit boards. Indoor H2S concentrations were higher than outdoor ones and these corresponded to the G2 and/or G3 levels defined in ISA S71.04-1985. The chemical composition of the copper sulfide creep indicates that it consisted of copper, oxygen, and sulfur. Crosssectional observation and elemental mapping analysis showed that Cu2S creep initiated not at the edge of the organic coating (organic solder preservative, OSP) inside the vias butmainly at defects in the organic coating covering the copper. (C) 2016 Elsevier Ltd. All rights reserved.