Hi Vlad! If I am interpreting Inge's photo number 4 correctly [realize I didn't get to see it on the SEM in person : - ) ], I see the nickel surfaces which have no wetting of solder. Gold dissolves into solder at 100 uinches per second (Bader data) there should be no gold on those surfaces. In brittle interface fracture, I expect to see very few regions of nonwetting - the failure is due to the poor properties of the Sn/Ni intermetallic (e.g I get good wetting, its just not a strong interface). In cases of black pad, I expect to see very few regions of good wetting, the nickel surface has been corrupted such that I don't form the Sn/Ni intermetallic (e.g I get terrible wetting and never form a good interface). Thus my comments for picture 4. Dave Vladimir Igoshev <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 05/04/2007 04:12 PM Please respond to TechNet E-Mail Forum <[log in to unmask]>; Please respond to Vladimir Igoshev <[log in to unmask]> To [log in to unmask] cc Subject Re: [TN] Metalurgists, need assistance Hi Dave, I'm lost:-) how come you know there was no Au in the areas where we see Ni? Brittlle Failed ENIG joints wqill have a similar "muddy" appearance Regards, Vladimir -----Original Message----- From: TechNet To: [log in to unmask] Sent: Fri May 04 16:45:09 2007 Subject: Re: [TN] Metalurgists, need assistance Hi folks and thank you Steve for being "TechNet Picture Central"! Sorry but just to warn everyone but I am going to use the "B" word shortly. Inge - take a close look at picture 4. As Werner pointed out the gold is non-wetting the nickel in number of locations. What really jumped out at me is that "mud flat" appearance on some of the nickel surface regions - a "mud flat" appearance is a classic indication of black pad! I recommend you complete a cross-section to confirm that you have nickel grain boundary attack. But since it is Friday, go have a beer and worry about this on Monday! Dave Hillman Rockwell Collins [log in to unmask] Steve Gregory <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 05/04/2007 01:45 PM Please respond to TechNet E-Mail Forum <[log in to unmask]>; Please respond to Steve Gregory <[log in to unmask]> To [log in to unmask] cc Subject Re: [TN] Metalurgists, need assistance Hi Inge! Got your pictures posted. Took me a bit, I was swapping our wave solderpot from 63/37 to HMP. Done now. I'm getting quicker, I can do it in 20-minutes now. Took me about 45-minutes when I first did it... Anyways, here's the links: http://stevezeva.homestead.com/files/Pic1.jpg http://stevezeva.homestead.com/files/Pic2.jpg http://stevezeva.homestead.com/files/Pic3.jpg http://stevezeva.homestead.com/files/Pic4.jpg http://stevezeva.homestead.com/files/Pic5.jpg http://stevezeva.homestead.com/files/Pic6.jpg -Steve- -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Hfjord Sent: Friday, May 04, 2007 12:22 PM To: [log in to unmask] Subject: [TN] Metalurgists, need assistance Have an issue with (randomly) lifted FPGA leads. Pic 1: good joint after pull test Pic 2: ditto but high magnification Pic 3: "rotten" joint after pull test Pic 4: ditto but high magnification Pic 5: "rotten" cross section Pic 6: ditto but high magnification 60Sn on ENIG, obviously a brittle region. Suspect Kirkendall voids, but the pockets with zillions of Tin spheres (0.1 to 2 um in size) points at insufficient peak temperature to make 100% melt and good solidifying. If these little balls were Lead, I could understand, but they are Tin! Never seen like. Any "quickhead" out there, need fast advice. Note: Pic 2, you can see the underlying board pad nickel as dark areas. An experienced analyst will hopefully recognize. No Phosphorous peaks! My Friday headache. Inge --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------