Dave, There are several other studies that confirm the formation of Au0.5Ni0.5Sn4 on top of Ni3Sn4. This IMC layeris formed at a quite a short time at temperatures above 100 degree C. Below is a list of references to some of them. A. Eslambolchi, P. Johnson, M. Kaufmann och Z. Mei, Electroless Ni/Immersion Au Evaluation – Final Program Report, Electronic Assembly Development Center, Hewlett-Packard, Palo Alto, 1998. K. Zeng och K.N. Tu, Six Cases of Reliability Study of Pb-free Solder Joints in Electronic Packaging Technology, Materials Science and Engineering R, Vol. 38, 2002, sida 55-105. R. Darveaux, K. Banerji, A. Mawer och G. Dody, Reliability of Plastic Ball Grid Array Assembly, J.H. Lau (Ed.), Ball Grid Array Technology, McGraw-Hill, Inc., 1995, Kapitel 13. H.G. Song, J.P. Ahn, A.M. Minor och J.W. Morris, Au-Ni-Sn Intermetallic Phase Relationships in Eutectic Pb-Sn Solder Formed on Ni/Au Metallization, Journal of Electronic Materials, April 2001, Vol. 30, Issue 4, sida 409-414, http://www.lbl.gov/morris/private/papers.html. A.M Minor och J.W. Morris, Jr., Growth of Au-Ni-Sn Intermetallic Compound on the Solder-Substrate Interface After Aging, Metall. Mater. Trans, A, 31A, 2000, p. 789. http://www.lbl.gov/morris/private/papers.html. A.M. Minor och J.W. Morris, Inhibiting Growth of the Au0.5Ni0.5Sn4 Intermetallic Layer in Pb-Sn Solder Joints Reflowed on Au/Ni Metallization, Journal of Electronic Materials, October 2000, Vol. 29, Issue 10, sida 1170-1174. http://www.lbl.gov/morris/private/papers.html. Per-Erik Tegehall IVF Sweden -----Ursprungligt meddelande----- Från: Dave Chapman [mailto:[log in to unmask]] Skickat: den 4 juni 2003 17:09 Till: [log in to unmask] Ämne: Re: [TN] BGA problems on ENIG http://www.binghamton.edu/physics/cottsectc.pdf Here is the link to the study, sorry. Dave C. -----Original Message----- From: Eric Dawson [mailto:[log in to unmask]] Sent: Wednesday, June 04, 2003 9:53 AM To: [log in to unmask] Subject: Re: [TN] BGA problems on ENIG Dave, Do you have a reference so we can read the paper/study please? Regards Eric Dawson > -----Original Message----- > From: Dave Chapman [SMTP:[log in to unmask]] > Sent: Wednesday, June 04, 2003 3:39 PM > To: [log in to unmask] > Subject: Re: [TN] BGA problems on ENIG > > Hi, just got e-mail from board supplier warning of tendency of BGA breaking > off ENIG pads. Citing a study at University of NY at Binghamton from a few > years ago. Claim growth of (Au0.5Ni0.5) at the Ni3Sn4/solder interface > promoting brittle joints. Board house was using HASL and we prefer Immersion > Silver but hadn't heard of the ENIG problem with BGA's > Any comments? > Dave Chapman > Manufacturing Engineer > Circuit Service Inc. > > --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------