PQFP Production Scanning

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 Production Scanning

PQFPs Production Scanning - Application Note 434

PQFP Production Scanning

Sample & Method

A tray of 24 PQFPs was imaged at high resolution on the automated FACTS2 system, shown above. FACTS2 scans the entire width of the tray at a time, and thus scans the tray as though it were a single very large component. Gating of the return echoes was on the depth of the lead frame within the plastic PQFP packages. High resolution (4096 x 2048 pixels) was used to enable secondary use of the FACTS2 tray image for analysis.

Result

Ultrasonic reflections of medium intensity from the gated depth are imaged in gray. Medium intensity would be expected from bonded internal interfaces (such as those between the molding compound and the lead frame) that reflect a portion of the ultrasound.

The most intense reflections are red and are represented here by a single PQFP package in the top row. High resolution permits the magnification of this package as shown in the inset. The circular gap-type defect pattern surrounding the die is typical of a popcorn crack resulting from the sudden expansion of trapped moisture.