FTIR, SEM/EDS and ion chromatography used in concert with a pair of extraction methods offered varying degrees of precision.
A group of 25 conformal-coated, no-clean assemblies was placed in an environmental test chamber at 40°C/90%RH for 168 hr. under functional conditions. Each assembly was tested with its plastic/metal enclosure on the unit; large openings in the enclosures permitted the assemblies to be exposed to the environmental conditions. Twenty-two units produced dendrites in multiple locations; all grew shorts on the SMT pad without components (FIGURE 1). The units were biased with 3.3V for 168 hr. at 40oC/90%RH.
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