Die Attach Delaminations
CSP Die Attach Delamination, Through Transmission - Application Note 657
Sample & Method
A group of 9 CSP packages were imaged with C-SAM® at 30 MHz. The die in these very thin packages is positioned face up. Wire bonds run from each die to a substrate attached to solder balls below the die. Molding compound protects the face of the die and the sides of the package, so that the area of the package is slightly larger than the area of the die.
The dark areas in the acoustic image are delaminations between the die attach material and the die. Probably many of the delaminations are larger than their original sizes because they have expanded laterally as thin cracks.