Electro-Chemical Paper Published at SMTAI 2015

Electronic Assembly Pitting / Crevice Corrosion Research

 

ABSTRACT

 

Pitting or crevice corrosion on printed circuit boards has not been well studied in the industry. This mechanism has been seen at small solder mask openings near circuit traces on printed circuit boards when stored or shipped in a humid environment with soldering fluxes that pass all standard tests. Failure modes are theorized to be driven by openings or defects in solder masks, voltage bias, flux activity and humidity levels. The High Density Packaging User Group Consortium is investigating this failure mechanism and the factors that cause the defect to occur.

Pitting / crevice corrosion is different than the well-studied electrochemical migration dendritic corrosion events. Test vehicles used to simulate pitting / crevice corrosion failure have been designed. Experiments to test the research hypothesis that pitting / crevice corrosion can occur on printed circuit boards soldered with no-clean wave fluxes are in progress and results to date will be documented in this research paper. This paper covers the correlation phase by comparing and contrasting existing IPC Test Methods to a newly designed Pitting / Crevice Corrosion test method.

A description of the mechanism, data findings, inferences from the data findings and follow on research plans are reported in this paper.

 

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