We do copper pours on FR-4 boards and have run into similar problems.
  With a dry film type of mask you will get peeling unless you hatch the
  copper. LPI works great, so that's what we use now. If you absolutely
  have to have solid copper pours, you'll probably have to pay the higher
  price for the LPI.

  Andy Buonviri
  ([log in to unmask])

  >We recently completed a single sided FR-4 design with a large area that
  we "poured" copper into.  Two of our three high volume board shops said
  no problem >when they reviewd this design. However our third house said
  that it there is a possibility of a problem because we use a screenable
  solder mask and they have a >worry about possible flaking of the mask on
  the large copper area.  They recommended two ideads:
  >
          1.  Hatch the copper pour instead of leaving it solid.

  >Our answer to this? (Ameritech Commercial guy) ....MMMMM.......NO.  We
  need it there for RF and ESD reasons I can't discuss.

          2.  Hatch the solder mask every 1/8 of an inch.

  >Again our answer to this is .....MMMMMM.......No.  This would gobble
  solder out of our wave machines for no good reason.
  >
  >So we said how about LPI and they said sure for a significant price
  increase.  Out of the three board houses this is the one who always gives
  us the best product >at the cheapest price with the least amount of
  rejects.
  >
  >SO WHAT DO WE DO NOW ?  We want to continue to use the solid copper pour
  feature on future products.
  >
  >Your thoughts would be appreciated.


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