Thanks, Reuven This brings me to the question of PbCO3 lead whiskers. They must be caused by internal stressors. If seen around the widest diameter of the lead balls like in Inge's case where no electro-chemical reaction would be the cause if the balls were actually a Pb90/Sn10 alloy, the whiskers are likely caused by the lateral stresses from the CTE mismatch between the aluminum oxide CBGA substrate and the PWB substrate the components are soldered to. These stresses would thus be concentrated near the widest part of the ball. If the balls are lead plating over some other metal, the lead whiskers would be from stresses due to the plating, and would not be focused on the equator, but distributed evenly over the ball. -----Original Message----- From: [log in to unmask] [mailto:[log in to unmask]] Sent: Tuesday, September 12, 2006 8:17 AM To: Stadem, Richard D. Subject: RE: [TN] PbCO3 I don't think so, dendrites caused by electro - chemical reaction and whiskers caused by internal stress and because of metallurgical structure. Best Regards Reuven ROKAH e mail: [log in to unmask] "Stadem, Richard D." <Richard.Stadem@g To d-ais.com> <[log in to unmask]> cc 12/09/2006 16:07 Subject RE: [TN] PbCO3 So is there a relationship between the microcrystalline dendritic growth (size and shape) in metals and whisker formation? -----Original Message----- From: [log in to unmask] [mailto:[log in to unmask]] Sent: Tuesday, September 12, 2006 8:02 AM To: TechNet E-Mail Forum; Stadem, Richard D. Subject: Re: [TN] PbCO3 Hi Stadem, According my best knowledge, Dendrites phenomenon, look like roots and they are on the surface, Whiskers phenomenon, look like a needle and grow from the surface / solder joint in different angels. Best Regards Reuven ROKAH "Stadem, Richard D." <Richard.Stadem@G To D-AIS.COM> [log in to unmask] Sent by: TechNet cc <[log in to unmask]> Subject Re: [TN] PbCO3 12/09/2006 15:44 Please respond to TechNet E-Mail Forum <[log in to unmask]> ; Please respond to "Stadem, Richard D." <Richard.Stadem@G D-AIS.COM> Reuven, Can you tell us the difference between dendrites and whiskers? -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Reuven ROKAH Sent: Tuesday, September 12, 2006 7:04 AM To: [log in to unmask] Subject: Re: [TN] PbCO3 Hi Ingemar, 1. Are you sure its Lead (Pb) Wishers? pls inform how? 2. Dendrites is another phenomenon than whiskers. 3. Can you repeat with this kind of failure? ("whiskers?"). Best Regards Reuven ROKAH e mail: [log in to unmask] "Ingemar Hernefjord (KC/EMW)" To <ingemar.hernefjo [log in to unmask] [log in to unmask]> cc Sent by: TechNet <[log in to unmask]> Subject Re: [TN] PbCO3 12/09/2006 12:56 Please respond to TechNet E-Mail Forum <[log in to unmask]> ; Please respond to "Ingemar Hernefjord (KC/EMW)" <ingemar.hernefjo [log in to unmask]> Klein Wassink mentiones a little about Tin Whiskers (dendrites). One guy here at our company has written a paper about Tin whiskers. NASA have a lot about Tin whiskers. Et cetera. But few have anything about Lead whiskers. Only thread I have is one picture from Klein Wassink. That picture is like a copy of our own photos. Question is if anyone of you have any idea about the following: A. Can Lead whiskers grow through Humiseal acrylic? I've heard that Tin whiskers can. B. Can alcalic saponifier cleaning of BGA high lead balls start whisker formation? C. Do Lead whiskers burn off easily like Tin whiskers, or are they "stronger" ? D. What can the reason be that the Lead whiskers grow only around the ball's "equator" ? E. The CBGA platform is said to come from IBM. Do they differ from others on ball making? These questions may not be suitable for this forum, but I make a try, well knowing that many of you are extremly experienced. Thx in advance Ingemar Hernefjord Now SAAB Microwave Systems --------------------------------------------------- Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------