I agree with Ted. I have used the .019 pad stack with excellent success. Dog bone at .008 min and direct hit to plane & .0275 clearance. 4n4 (.005 bonus for fabricator). External row route only on BGA side. Tent vias and if possible don't use as test points. I have used this on 13 x13 +inch boards that are .100 thick, no sequential lam or microVia. You will have aspect ratio of >7.5/1 so select a supplier that can perform. Allow tangency not breakout. Boston Brad --------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e 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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) 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 -----------------------------------------------------