As a manufacturer of high-rel and Mil Printed Circuits, we have seen an increasing number of board designs that require the use of (LPI)Liquid Photo Imageable soldermask. The LPI masks perform well in most cases, but many of these designs incorporate tented via's. In the past, Dryfilm soldermasks have been used for boards with tented via's, but many customers are moving away from the dryfilm soldermask. We are currently using a "via fill" process in which we fill the holes with an epoxy s/m by screen printing. This is followed by application of the Liquid Photo Imageable (LPI) soldermask over the surface of the board. The result is an LPI mask with tented via's. To me, this process seems to be a step backward on the technology curve. It requires more process steps and more time. We would like to get away from the screen printing and pursue a 100% Photo process. I have discussed this issue with several soldermask suppliers, and I have been told that this is a very common procedure and that many other board shops use the same process. None of our suppliers have offered a more effective solution. I would be interested in any feedback related to the use of LPI soldermask when tented via's are required. Would anyone like to share their "success" stories or recommend a supplier that could help with this issue. Thank you in advance for your comments. Sincerely, Jim McNeal ===================================================== Jim McNeal Q.A.and Eng. Mgr. Electro Plate Circuitry, Inc. Carrollton, Tx Ph. 214-466-0818 EMAIL [log in to unmask]