HADCO uses LPI soldermasks almost exclusively, and we also "plug" the vias from one side with a wet mask dot pattern. Tha only difference is that we perform the process in the following sequence: LPI soldermask hot air solder level wet mask via plug In this way, the via barrels have a solder coating on them, which we consider more reliable. I agree with you 100% that this is almost a technology step backwards, but it is the best we can do for now for those of our customers who need plugged vias, either for vacuum purposes at loaded board test, or to reduce bridging vias sitting under components. Always make sure that you don't plug a via which is needed as a test point. We have also found it difficult to plug vias drilled >.020". Tom Coyle Customer Services Engineer HADCO Corporation [log in to unmask]