Sonoscan Application Note 355

Heat Sink and Adhesive

Acoustic image showing head sink and adhesive, no significant defects

A flip chip having an adhesively attached heat sink was imaged from the top side at 100 MHz. Gating is on the interface between the heat sink and the back of the die.

Result

The dark square area at center is the die. The heat sink is considerably larger than the die and has four cutouts (white and tan features). Note the somewhat irregular outline of the adhesive layer (dark brown). No significant defects are present at this depth in the package.