That was a very good explanation. With the advances in process controllers and software I would think or expect that the ENIG process is less risky now than some 10 years ago when I used to hear about these issues. I know from a manufacturing poit I'll take ENIG over OSP any day. -------------- Original message -------------- From: Inge <[log in to unmask]> > Can we call it 'Black Pudding' instead, as it is a mess of obscure > ingredients? > Inge > > > ----- Original Message ----- > From: "Wenger, George M." > To: > Sent: Friday, November 21, 2008 10:47 AM > Subject: Re: [TN] black pad > > > That is how a lot of the confusion around (I hate t > > Peter, > > That is how a lot of the confusion around (I hate the name but I need to > use it here) Black Pad started. Creep fatigue cracking, brittle > fracture, etc. are recognized failure modes or mechanisms, "Black Pad"," > Black Line Nickel", etc. are not names of recognized failure modes. > They are names of what people see when they look at a failure. They > are short cute names that people like to repeat but they don't help to > describe what the failure is or what caused it. All I know about "Black > Pad" is that it happens with ENIG, it's a low level problem that follows > Murphy's Law (i.e., it happens when you least expect it and usually and > an inappropriate time), it might be caused by a high P content at the > interface, it might be caused by "weak" electroless nickel, it might be > caused by cavitation and attack at grain boundaries, it might be cause > by too much gold plating attaching the under lying nickel, it might be > caused by board shops not controlling the ENIG process properly, etc. > There are just too many "might". The data that has been generated by > many over the last couple of years certainly shows that control of the > plating chemistry is a key to reducing the occurrences of "Black Pad" > failures and the number of occurrences has certainly decreased but the > failures certainly have not been eliminated. Many of the ENIG failures > I've seen over the years are fractures at an interface. Vladimir would > certainly not agree with calling all ENIG failures "Black Pad" and I'd > agree with him. I'd much rather refer to the ENIG failures as "ENIG > Interface Failures" rather than "Black Pad" but that will never happen > because "Black Pad" is a cute and short 8 letter name that can even be > shorted to two ("BP"). It takes 23 key strokes to type "ENIG Interface > failures". > > > Sorry for the long answer but it's Friday and I had an exhausting week. > > Regards, > George > George M. Wenger > Andrew Wireless Solutions > Senior Principle FMA/Reliability Engineer > 40 Technology Drive, Warren, NJ 07059 > (908) 546-4531 (Office) (732) 309-8964 (cell) > [log in to unmask] > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Pete Houwen > Sent: Friday, November 21, 2008 12:54 PM > To: [log in to unmask] > Subject: Re: [TN] black pad > > not to step in a place I don't beloing, between werner and Vladimir, but > how > about "dark line defect" instead of "black pad"? > > Similar phenomenon for a different reason. > > We went through this a while ago, wondering why suddenly boards from a > very > good ENiG supplier were looking like black pad, all that P on top of the > pad. > Changing reflow profiles to reduce TAL and max temp, reducing rework > cycles > made it all go away. All that extra time at temperature just continued > the > Ni/Sn reaction, leaving P behind. Quantities of Ni in the Sn tipped us > off that > we weren't starting out with black pad, but we were ending up with it. > > I do get why people don't like ENiG, but we've done very well with it by > making > sure we use good suppliers. > > Pete > > --------------------------------------------------- > 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 > ----------------------------------------------------- > > -------------------------------------------------------------------------------- > ---------------- > This message is for the designated recipient only and may > contain privileged, proprietary, or otherwise private information. > If you have received it in error, please notify the sender > immediately and delete the original. 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