PBGA 3D Sectioned Voids

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.

PBGA 3D Sectioned Voids

PBGA 3D Sectioned Voids in Molding Compound - Application Note 210

PBGA Sectioned Voids
Acoustic image left, optical image of PGBA middle, diagram right

Sample & Method

The Acoustic Solid shown in Application Notes #202 and #206 has been sectioned in two geometric planes to reveal the die attach region and other internal features.

Result

The die attach region (square blue area) shows some differences in acoustic intensity (light and dark blue), indicating variations in the die attach. The numerous small voids (yellow) in the molding compound, seen in Application Note #206, are also seen here.