Hi Per-Erik! Yes, I have found that mechanical abrasion can be used to restore BGA pads which have been impacted by black pad but I didn't offer that method of restoration as a solution - the amount of collateral damage to the soldermask around the pad sites usually results in bridging defects during the component replacement phase. And I don't seem to be very popular on the manufacturing floor when I suggest that we need to abrade every pad on a +500 I/O BGA! Dave Tegehall Per-Erik <per-erik.tegehal To: [log in to unmask] [log in to unmask]> cc: Sent by: TechNet Subject: Re: [TN] Black pad <TechNet@listserv .ipc.org> 08/12/2003 04:27 AM Please respond to "TechNet E-Mail Forum."; Please respond to Tegehall Per-Erik Hi Werner and Dave, The black colour on pads with the defect "black pad" is, in most cases, due to an enrichment of nickel phosphide that occurs during the plating of immersion gold. Some nickel is always etched from the surface in this process but if the process is not under control too much nickel may be etched away and the phosphorus in the electroless nickel will be enriched as NiP in the interface between nickel and gold. I believe it will be very difficult to remove it chemically. I think I have read somewhere that that someone removed it mechanically and then soldered directly to the nickel surface. A fresh electroless nickel surface has moderate solderability and with the right soldering process it might be possible to solder to it. Per-Erik Tegehall IVF, Sweden -----Ursprungligt meddelande----- Från: Dave Hillman [mailto:[log in to unmask]] Skickat: den 11 augusti 2003 21:31 Till: [log in to unmask] Ämne: Re: [TN] Black pad Hi Werner! We have tried to use our ROSA system to electrochemically reduce the degraded nickel surfaces with no success (nickel oxide/corroded nickel is tough stuff!). I have not heard of anyone being able to restore a "black pad" surface successfully without having collateral damage to adjacent regions of the printed wiring assembly. Hey Rudy S. - is there a chemical treatment potential/possibility? Dave Hillman Rockwell Collins [log in to unmask] Werner Engelmaier <[log in to unmask] To: [log in to unmask] OM> cc: Sent by: TechNet Subject: [TN] Black pad <TechNet@listserv .ipc.org> 08/11/2003 02:09 PM Please respond to "TechNet E-Mail Forum."; Please respond to Engelmaier Hi All, Are there any successful rework procedures for 'black pad'? Werner Engelmaier --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------