Dear Technos, We're having an FR-4 PCB on which we will assemble a few SMT parts and then this board will be bonded onto a flex cable. The bonding will be done on about 140 x 50microns wide "gold fingers". The smallest SMT features on the board are the 232 pads of a BGA, 250 microns in diameter, so a little less than 10 microINCHES. The PCB plating spec that was proposed is 10 to 20 microINCHES of Au (per an ASTM spec, not sure, maybe 448?) on 150 to 250 microINCHES of Ni. Unfortunately, I don't know whether we talk about ENIG or rather hard or flash Au. Is this plating OK for bonding? What about the gold embrittlement on the SMT components side, the spec might be OK for the Ni, but strongly contradicts the 2 to 5 microinches of Au as per IPC-4552? Is it common practice, or at least acceptable to have the same finish on the SMT pads and the surfaces to be bonded? What would be a proper specification for this kind of PCB? Thank you, Ioan --------------------------------------------------- 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 -----------------------------------------------------