Rick, You will, of course require one via per BGA ball, and the only places to put them are either adjacent to the pad or in the pad itself. There just ain't no room to do surface fanout to the outside of the foot print. Conversely, there ain't enough room to put other vias inside the footprint, other than the ball interconnect vias, 'coz all the space is taken up. Or am I missing something here? Peter Rick Howieson <RHowieson@DELTAGRO To: [log in to unmask] UPINC.COM> cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST Sent by: TechNet Aero/ST Group) <[log in to unmask]> Subject: [TN] BGA/Vias 01/17/02 01:41 AM Please respond to "TechNet E-Mail Forum."; Please respond to RHowieson We have a board with a BGA that has quite a few vias on the board located under the BGA. My question is...Should there be a limit of vias on the board located under the BGA? When we need to rework the BGA that area of the board seems to "sink" causing more problems, not to mention the integrity of the vias. Thanks, Rick Howieson Delta Group Electronics, Inc. --------------------------------------------------------------------------------- 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 previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 --------------------------------------------------------------------------------- [This e-mail is confidential and may also be privileged. If you are not the intended recipient, please delete it and notify us immediately; you should not copy or use it for any purpose, nor disclose its contents to any other person. Thank you.] --------------------------------------------------------------------------------- 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 previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 ---------------------------------------------------------------------------------