Steve:

Just read a bunch of the responses and thought I'd add my comments.  The defects
appear to be "mouse bite" type defects rather than resist breakdown.  Air saturation
is one possible cause of mouse bites and inadequate or improper cleaning before
copper is another.  A plated resist (tin or tin/lead) will often exhibit
circumferential voids at the knee of the hole before pits appear in the circuits.
The suggestion to examine a cross section of a pit is the best way to determine if it
is a copper plating defect or an etching defect.

In any case, IMO the boards do not comply with the requirements of IPC-6012.  My past
experience is that your supplier may have a on-going process issue, and you should
meet with them soon to review the defects you received and how they will guarantee
that you won't receive any more defects.

Regards,
Don Vischulis

"Stephen R. Gregory" wrote:

> Hi Ya'll!!
>
> It's picture time again! Got some boards in at incoming inspection that are
> really weird looking Go to:
>
> http://www.driveway.com/share?sid=e25a88c4.8e904&name=Pictures
>
> Look at Pits.jpg and Pits2.jpg...very, very strange! Never have seen
> something like
> this before...and it's only on the backside of the board? What could cause
> this?
>
> Looking in the IPC-A-600F, it only talks about reductions in conductor width
> of more than 20% (for class-2), but doesn't talk about reductions in
> thickness by pits such as these...it's hard to tell if they've gone all the
> way through the trace because the pits are filled with solder mask and you
> can't see all the way down to the bottom of the pits.
>
> Common sense tells me that these boards are rejectable...am I right?
>
> -Steve Gregory-
>
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