An IR LED was submitted for failure analysis. The LED had failed during process validation testing.
These are optical images of the IR LED documenting the results of external examination.
This image shows a microsection just after grinding into the cup. The angle of the gold bond wire near the wire bond appeared to be anomalous.
The open-circuit failure was caused by bond wire fracture that occurred just above the wire bond.
This is a higher magnification image of the fractured bond wire.
The failure was most likely caused by thermal (or possibly mechanical) stress putting tension on the bond wire, and there may have also been some damage to the bond wire as a result of the original wire bonding process during fabrication of the LED.