IPC Minimum Via Wall Specification Deviation

[ashepard]

Does anyone out there have any experience using via wall plating thicknesses less than the IPC-A-600 standard (18 microns). I have a vendor that wants me to approve a deviation allowing them to meet a reduced plating thickness of 6 microns. I understand the potential risks involved with this reduction in via wall plating thickness, but need cold-hard facts to back-up my objection.

 

[SteveBull]

I should be very careful, this sort of thickness will be very likely to suffer from voids in the barrel of the via, and dependant on the method of manufacture, you may not even get the copper to meet in the centre of the hole.
Ally this to the fact the 6um is likely to break open under significant thermal shock, like the soldering process, and I would be hiding my pens. Please tell me this is going into childrens toys, or something equally non-safety critical.

Steve Bull

Circuit and Quality Engineer

PS...why do they want to do this, was the circuit badly designed? had they drilled the holes too small? tell me, I'm fascinated

 

[jbartos]

Suggestion: Visit

http://www.techplate.com

http://www.techplate.com/specchart1rev.htm

http://www.ipc.org/html/A600F.htm

http://standards.nasa.gov/stdsearch.taf?discpln=9

etc. for more info