We are having an issue with bare boards, where it seems that one or two
panels get less plating thickness than others. The fact that it seems to be
a rare occurrence makes it even harder to pin down.
The fabricator says they are shooting for 1.2 mils plating thickness, but a
few of them at seemingly random times are more like an average 0.6-0.8 mil
(we require average 1.0 with nothing less than 0.8)
We can see it by cross sectioning coupons or x-out boards of course, but
are there any other non-destructive methods of checking plating thickness
accurately? The thought of doing a micro-section on every panel is
intimidating.