I don't think anyone has provided the information that tenting vias is required if you want to draw a vacuum for the tester. If there are a lot of holes open and you do not use a rubber "blanket" to close the holes, then you get "whisteling" and not a tight draw for pin contact. The true way to tent is to use dry film. If this is not acceptable then a dot pattern of UV cured ink on the bottom side is ok if there are no test points that need to be open. Fab vendors have a lot of methods with LPI. *************************************************************************** * 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. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************