Hi Alvin,
Colin Lea in the UK did quite a bit of work on this in the late 80's--a good
deal of it can be found in his book "A Scientific Guide to Surface Mount
Technology," Electrochemical Publications, 1988.
It is a time/temperature issue--how long before the IMCs grow through the
surface and affect solderability. Yo my knowledge, little has been done in this
regard with LF-solders.
I will touch on some of this in my workshops that I will be giving in
Singapore May 4 & 5--for more detail on this please contact Chua Eng Guan at
www.upstar.com.sg.

Regards,
Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL 32174 USA
Phone: 386-437-8747, Fax: 386-437-8737, Cell: 386-316-5904
E-mail: [log in to unmask], Website: www.engelmaier.com


---------------------------------------------------
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
-----------------------------------------------------