Article ID: M2018221
This work details how devices mechanically separated from wafers with a dummy pattern in their scribe region can undergo serious reliability degradation due to Si3N4 damage. Experimentally, it was found that although chipping damage occurs only within the scribe region, Si3N4 damage can grow up to the active region, which is far away, beyond the chipping damage range, because inappropriate Si3N4 coverage in the scribe region can be a carrier for damage propagation during sawing. Further, this work shows that Si3N4 damage existing in the scribe region even after wafer separation completion can further attack the active region and cause device failure during thermal-cycling. So, this work suggests that appropriate design of the amorphous Si3N4 layer in the scribe region is essential in order to allow the devices to have better reliability margins during thermal-cycling as well as mechanical wafer separation.