Roger, I'm working on electroplated Nickel on copper, I would like to more about your experience with Copper diffusion into Nickel layer. We work on silicon wafers here. Any input from you will be greatly appreciated. Yasmeen Roger Massey-G14195 wrote: > 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 ##############################################################