I have a .035 dia soldermask pad with no hole in a circular array pattern
that I use over our mounting holes so we can skip a spot mask process in
manufacturing. My question is : is this size pad too small to expose or
develop when using LPI soldermask . I have two vendor who are having
trouble with this pattern and when I get the boards in I have what looks
like exposed copper contained on some of the pads. We know that they are
not really exposed or else they would have covered in the HASL process or
would be discolored due to contamination. The pads are just as bright
copper color as you would expect to see before LPI soldermask is applied.
Anyone have any thoughts.

Steve Collins
PCB Design Supervisor
Antec
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