PQFP Die Cracks

Pictured

Time Domain Imaging (TDI)™
Utilizes an echo (amplitude & polarity) arrival ‘time’ as a reference, such as standard A-Scan, B-Scan and C-Mode type images.

PQFP Die Cracks

PQFP Die Cracks - Application Note 147

Sample & Method

A PQFP was imaged from the top side at a frequency of 50 MHz. Gating was at the die surface to mold compound interface.

Result

The longer red areas are cracks in the die. Gray areas are free from cracks and are well bonded to the molding compound. Some of the smaller red areas at the periphery of the die (at the upper left corner, for example) are small delaminations rather than cracks. Small portions of some of the cracks are black rather than red. Die cracks frequently result from poor handling mechanisms, but the number and distribution of cracks in this sample make it more difficult to diagnose the cause.