SPEL has introduced the QFN packaging with Wettable terminal flank option for automotive applications. To ensure that cars meet today’s demand for safety and high reliability, the automotive industry needs original equipment manufacturers (OEMs) to perform 100% automatic visual inspection (AVI) post-assembly. In the case of quad-flat no-lead (QFN) packages, there is no easily viewed solderable or exposed pins/terminals that enable one to determine whether or not the package is successfully soldered on to the printed circuit board (PCB).

To resolve the issue of side lead wetting of leadless packaging for automotive and other commercial component manufacturers, the wettable flank process was developed. This provides a visual indicator of solderability and lowers the inspection time.

The technique makes a step cut into the leadframe on the bottom side before plating. This increases the solder joint surface between the package and substrate, improving solder wettability to allow for easy verification of solder condition after mounting. Hence using a QFN package with a wettable flank option enables optical inspection of the soldering which can increase solderability while reducing cost.