Been there, done that, have pieces of broken solder mask to prove it. If the ground plane is large enough on a sn/pb plated board, the bubbeling and flaking will occurr. With a dry film mask, if the clearance is small enough and the mask thick enough the via pads will not wet with solder. Don Vischulis [log in to unmask] wrote: > > It is unlikely that any LPI soldermask will survive such reflow conditions as > you describe when applied over tin/lead. Possibly, a thick (3mils) dryfilm > soldermask would have a better chance. Is it possible to use soldermask over > bare copper, instead? > > Mark Dowding > Regional Technical Specialist > Insulectro