Delaminations in Substrate
PBGA MC to Substrate Delamination - Application Note 2600
Sample & Method
The strongest signals were reflected by the large white area at right. This area is a large delamination between the molding compound and the substrate. Significantly, the delamination includes the area of the wire bonds, meaning that the wires are subject to mechanical movement as the result of thermal cycling or vibration.
In the image the echoes from the ultrasonic C-SAM transducer were gated on the interface between the molding compound and the substrate.