Hi Leo - Don Cullin of MacDermid just presented the "latest and greatest" on the microvoiding phenomena associated with immersion silver finishes at the CMAP Conference in Toronto. I recommend you contact Don for a copy of his presentation. There were a significant number of very good technical ppts and discussions at the CMAP Conference. Dave Hillman Rockwell Collins [log in to unmask] Leo Higgins <Leo_Higgins@ASAT .COM> To Sent by: TechNet [log in to unmask] <[log in to unmask]> cc Subject 05/16/2006 08:39 Re: [TN] Question about ENIG and PM other surface finishing Please respond to TechNet E-Mail Forum <[log in to unmask]> ; Please respond to Leo Higgins <Leo_Higgins@ASAT .COM> In my experience microvoids associated with leadframe soldering to PCB pads are often associated with minor organic contamination of the leadframe surface prior to leadframe plating. This has been shown to result in significant decreased drop test performance in hand-held electronics. Based upon readings from a few sources it appears that microvoids associated with Immersion Silver are due to high organic level in a thick Ag deposit. Cookson/Enthone provides an interesting presentation on their AlphaStar ImmAg with a relatively thin deposit with low organic content (approx 1 -6 %, vs. a competitor level reported to be 22%). In my past experience with fluoroborate-based immersion Sn that produced a tin deposit about 0.2 micrometers thick, I never saw microvoids, but I did see degraded solderability with time and temp due to the thin deposit and tin consumption with the creation of Sn-Cu IMCs. While I have no direct experience with this Enthone tin, the presentation shows it to be quite environmentally robust even with a deposit about the same thickness. Best regards, Leo Leo M. Higgins III, Ph.D. Vice President, Technical Operations ASAT, Inc. 3755 Capital of Texas Highway, Suite 100 Austin, Texas 78704 office phone 512-383-4593 mobile 512-423-2002 [log in to unmask] www.asat.com -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Werner Engelmaier Sent: Tuesday, May 16, 2006 4:05 PM To: [log in to unmask] Subject: Re: [TN] Question about ENIG and other surface finishing Hi Kerry, Here are pics of micro-voids. Werner --------------------------------------------------- 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 -----------------------------------------------------