Issued Date: 2018/6/14
Issued By: iST
Components found burnt out when assembling finished goods in the system manufacturers, and the IC design house claims EOS is to blame.
As an IC designer, how do you quickly identify the location of burns and change circuits?
Static exists everywhere. Components tend to burn out due to electrical over stress (EOS) under current or voltage overload.
Finished goods manufacturers are pressed to deliver products as scheduled while assemblers are squeezing IC design houses to come up with solutions. Being an IC designer, what should you do to identify burnt areas in order to proceed with circuit design modification? The iST Tech Classroom presents some typical cases to help you pinpoint component EOS abnormal hot spots in 3 simple steps.
Step 1: Localization
Detect packaging defect by phase differences of thermal radiation at the failure point without damaging powered devices to quickly position the failure point (getting its XYZ coordinates).
Figure: Thermal EMMI image
Step 2: Identify delamination
Components suffering EOS tend to result in IC surface and packaging layer damaged due to high temperature which, in turn, leads to delamination at the EOS point. A scan with a non-destructive SAT (Scanning Acoustic Tomography) ultrasound may identify the position of packaging layer delamination, which is in the same location pinpointed by the thermal EMMI.
Figure: SAT image
Figure: Take out the die and OM verification