Title:

Contribution of Bondline and Ejector Needle Stress on the Occurrence of SOHED Cracked Die

Author(s):

Nelson Palang, Edgar Panganiban, Rose Galunan, Catalino Esteban Jr., Allegro Microsystems Phils., Inc.

Gist:

The cause of failures encountered in a particular Small Outlined Hall Effect Device (SOHED) was found to be die cracking. Furthermore, this die cracking issue was traced to the die attach station. The die cracks seen all traversed through the ejector needle mark of the die backside. This study showed that to reduce the occurrence of SOHED die cracking, there must be adequate die attach adhesive covering the whole die backside and its bondline must be consistently thick enough to absorb thermal and mechanical stresses. A less damaging ejector needle tip must also be used (in this study, the 10-deg needle was replaced with a 15-deg needle), while the ejector needle height must be minimized. The sequence timing of die pick-up and plunge-up was also found to be crucial to controlling the stress marks on the die backside.

Published in :

ASEMEP 1999 Proceedings; July, 1999