Dave, I can't tell you if it acceptable on a Class 3 board, but I can tell you that we used conductive epoxy successfully as a fix on some development boards that had an error. It "connected" the necessary internal layers and made the development boards work so we could continue testing. Phil -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Dave Connitt Sent: Tuesday, December 02, 2008 9:07 AM To: [log in to unmask] Subject: [TN] Conductive Epoxy filled Vias Hello List, We are considering implementing a 0.80 mm pitch BGA on a development project and I have question about escape vias. The part manufacturer recommends that we use a 0.019" pad with a 0.010" drill. The board has to be a IPC-6012 class 3 PWB and I would like to have a 0.003 annular ring on the escape vias. One of our board vendors suggested we use a epoxy filled via which would relieve us of the annular ring issue but I am not sure about still being a class 3 board. Does anybody know where I can confirm that epoxy filled vias are acceptable in a class 3 board? Thanks, Dave Connitt CID+ Printed Circuit Designer KDI Precision Products, Inc. A Wholly Owned Subsidiary of: L3 Communications 3975 McMann Road Cincinnati, Ohio 45245 Ph. 513- 943-2010 Fax 513-943-2288 --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- Note: All the information contained in this e-mail and its attachments is proprietary to Kaiser Systems, Inc. and it may not be reproduced without the prior written permission of sender. If you have received this email in error, please immediately return it to sender and delete the copy you received. --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------