Paul, Another thought to echo what others have said. Copper build-up in electroless nickel solutions, while not necessarily visible to the naked eye, will be incorporated into the nickel deposit. Then, as if by magic, the copper can migrate along grain boundaries in the nickel (solid State diffusion) and basically relocate to the surface of the nickel. This is one possible scenario for the copper you are seeing. Good luck, Mike Carano -----Original Message----- From: Roger Massey-G14195 [SMTP:[log in to unmask]] Sent: Thursday, August 26, 1999 3:02 AM To: [log in to unmask] Subject: Re: [TN] Nickel plating contaminants ; cracking propagations Paul, If the CuSn intermetallics are forming randomly across the surface, have you considered that the Ni layer is not strictly continuous, or more likely its porous. This would result with rapid Cu diffusion (via pore and grain boundaries) up onto the Ni layer, and hey presto theres yer CuSn chunks. Have you tried a surface scan of incoming boards looking for Cu? follow this with "reflowing" a board (without any components) and repeating the surface scans, if you see Cu at any time, then your boards are bad, and should be returned for cleaning, and replating if it can be done For the analysis, you may need to use a low penetration technique like auger, EDX may just punch through any small or thin Cu deposits. alternativly, cross sectioning and doing a Cu Xray map or line scan may show an increase in Cu concentration through the Ni layer Ive experienced this before with an electroplated Ni layer on Cu. Then the Hydrogen embrittled plating was cracking during transit, and also reflow. This resulted with rapid Cu diffusion up onto the surface, which was giving the same style of thing. Hope it helps, Roger Motorola AIEG ______________________________ Reply Separator _________________________________ Subject: [TN] Nickel plating contaminants ; cracking propagations ? Author: "TechNet E-Mail Forum." <[log in to unmask]> at #email Date: 26/08/99 10:51 This must be a problem season : after flakes, cabbages and roses , I have this copper "boulders" alloy problem : On our routine microsectioning of (4umNi + 0.3umAu; 63/37) joints we discovered we have rather interesting phenomenon : After the obvious dissolution of gold ; there are sitting on top of Nickel (admittedly bit thin ; still , continuous) microcracked boulders (about same dia as the Ni layer) . when we zoomed scan on them ; we found they're CuSn alloy ! Looks like a smallpoxed nickel face . Now our regular profiling 's telling us we're nowhere near this alloying scenarios ; and we ponder about the cracking propagations ; the Q is : Where are this aliens coming from ? Contaminants of tubs from some previous process ? Smudged sample polish ? Appears only on one specific fab supply . Paul Klasek http://www,resmed,com ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ############################################################## ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ############################################################## ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################