Depending on the process used, LPI can effectively plug vias. The question is how large the vias are and what percent failure is acceptable. As you state, however, the only way for 100% coverage of vias is to use a dry film solder mask. Many companies will accept 90% coverage and use an LPI. Bob Metcalf Morton Electronic Materials >>> <[log in to unmask]> 10/14/96 03:46pm >>> Item Subject: PLUGGED VIAS -Reply The only soldermask I am aware of that can plug vias is dry film mask. If there is an LPI mask that can covers vias can someone tell me about this. Thank You: Steve O'Hara ______________________________ Reply Separator _________________________________ Subject: PLUGGED VIAS -Reply Author: Non-HP-bmetcalf ([log in to unmask]) at HP-Vancouver,shargw2 Date: 10/14/96 11:12 AM If you are using a photo defined solder mask, you can control which pads are covered/filled and which pads are cleared. Bob Metcalf Morton Electronic Materials >>> Barry Darnell <[log in to unmask]> 10/14/96 11:41am >>> I have run into a problem with a board that has vias in smt pads. We need all of the vias plugged, and I am told that solder mask is the best way to do that. This is to ensure that a good vacuum is maintained for our ATE equipment. That is the problem. I can not have a via covered with solder mask on top of an smt pad. The board house I am using says this is difficult for them because they have to determine which vias are plugged and which are not. Anyone out there with any suggestions? Thanks, Barry Darnell (864)627-8800 Ext. 231 [log in to unmask] CD Electronics, Inc. Printed Circuit Board Designer *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * *************************************************************************** *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * *************************************************************************** *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * ***************************************************************************