Abstract:

Pre-plated leadframes packages with a new noble metal finish type were exposed to various electrochemical migration tests, and mixed flowing gas environments to assess the quality and reliability due to these environmental conditions. Packages were tested as discrete parts and also as parts mounted onto printed circuit boards to assess the effect of reflow soldering. Selected packages with SnPb plated leadframes were tested for comparison purposes. After test exposure, optical microscopy, SEM and EDS analyses were conducted to evaluate the corrosion behavior. Corrosion and creep corrosion on the leads were observed on all the pre-plated test samples subject to the mixed flowing gas. Creep corrosion over the mold compound surface was identified on the un-mounted QFN packages. The creep corrosion products were found to be electrically conductive and could bridge adjacent lead pairs.

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