A current design in our CAD department has vias inbetween BGA pads. They want to tent the vias. I was thinking of covering half of the pad of the vias with solder mask to increase the solder mask wall between a via and solder pad while still leaving the via open. Otherwise I have a question concerning via tenting. I know that the best situation is to leave the vias open. I know that you shouldn't tent only one side to avoid possible entrapment of flux. I know that if you tent both sides there is a chance of blow-out. What exactly happens to the PCB if there is blow-out and what is the actual cause of via blowout. Thank you. Best Regards, Mike Forrester [log in to unmask] ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################