Dear Mr ,
We have a in house facility for making hi reliability PCBs.
We use Park Nelco N4000-6 material (Tg=175 C ).
We use hot mounting techniques for PWB coupon micro section.
We polish up to 5 microns normally bur if a problem is found we go up to 0.05 micron polish.
We don't do micro etch. A Hi reliability PCB has failed in the field trials.
We analyzed the coupon again no problem found. We polished up to 1 microns still no problem found.
But when we micro etched the specimen we found a barrel separation.
Do the micro etch is essential in finding a fault?.
What are the false alarms possible and how to exclude ?
Kindly advise . regards.
Ramakrishnan Saravanan