Sample & Method

A PQFP was imaged from the top side at a frequency of 15 MHz. Gating was on the die attach.

Result

The yellow central area is die attach material. The red area is an extensive delamination where the die attach material is not bonded to the die above. Delaminations, whether large or small, are sites where moisture is likely to collect. Heat can cause the moisture to expand, further enlarging the delamination.