PackagePrep CE Tin S
QFN Packages: Small, Thin, and Now Inspection Friendly
QFN’s have become the preferred high density leadframe-based surface mount package. But the advantage of this versatile package comes at a price. Exposed copper at the singulated edge of the package solders poorly, preventing conventional solder fillets from forming. The lack of a visible solder fillet inhibits recognition by automated optical inspection (AOI). Furthermore, the smaller solder footprint creates reliability risk, limiting the end-use applications that designers will consider.
PackagePrep CE Tin S solves these problems. PackagePrep deposits an easily soldered metal finish on the exposed copper edges. After paste reflow, solder wicks up the side of the QFN flanks. The new QFN fillets are easily inspected by existing top-down AOI as well as visual inspection, supplementing x-ray inspection.
Planning to use QFN’s in your high reliability application, but concerned about reliability and inspectability? Let PackagePrep CE Tin S be your solution.
Components that operate in harsh environments, such as automotive and aerospace assemblies, must meet more stringent demands than other components. They must endure high temperatures, mechanical stress and corrosive conditions. While meeting reliability standards, components for automotive applications also require high density performance. The leadframe based QFN surface mount component has been a preferred product to meet both the reliability and higher density requirements and continues to show significant market growth. A past limitation has been the inspection difficulty of the assembled QFN. Before PackagePrep CE Tin S, terminal solder joints on QFN’s were hidden under the package and could only be inspected by x-ray. Exposed copper alloy on the outer QFN edges was often missing a visible solder fillet on the flank. The AOI inspection of the soldered, tin plated copper flanks allowed by PackagePrep enables a low cost high reliability solution to the stringent requirements placed upon QFN packages in automotive applications.