QFN Lead Delaminations - Application Note 2518
Sample & Method
Five Quad Flat No-Lead devices (QFNs). The return echoes were gated at the depth of the die, lead frame and paddle to molding compound interfaces.
The red and yellow areas are delaminations at these interfaces. These delaminations are a threat to reliability because they are close to the exterior of the package and provide a pathway by which moisture and contaminants can find their way to the wire bonds.