Dennis, Good to see from you again though your subject sucks. You know exactly what to do and what not. I'm fighting the same battle right now with some young engineers and designers. I did some of the first simple minded studies on BGA's with vias in pads many years ago. The solder goes away and you and everyone else knows it. Micro vias down about 4 mils are ok provide proper compensation is made for solder volume and the avoidance of outgassing. I've got some folks wanting to take a blind via down about 18 mils and just see what happens. Wow, will this never end. You know I respect you babe, MoonMan --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------