Hi Pat!

I don't think it's a good idea, we got burned by it once. The internal pads
will provide support during drilling, and will help prevent rough walls
during drilling.

In our case, the unused pads were removed (this was a fairly thick ~.093" or
so polyimide PCB) and plating chemicals were absorbed into the fibers from
the rough drilling. We built the boards, did ICT and a low power functional
test, everything was fine. The boards were shipped to our customer and they
plugged it into their system, powered it up, and then the board died after
about 20-minutes, internal short in the fab. They RMA'd the board back to us,
we sent it out for cross sectioning and found the problem.

Had the used pads put back in and haven't had a problem since.

-Steve Gregory-


> Hi TechNetters,
>
> For class 3 boards, is it acceptable to have unused pads removed on
> interanal
> layers.
>
> Thanks,
> Pat
>