Hi Bill! Yes, you may see a change in the solder joint appearance with the
use of the new alternative solderable finishes (e.g. immersion silver,
immersion gold, immersion tin, immersion palladium) depending on the type
of reflow profile you are using (inert or not inert, temperatures) and the
amount of solder paste you deposit (stencil thickness). Provided you have
acceptable wetting angles and acceptable solder geometries you should not
have a reliability issue unless you have a solder joint metallurgy issue
(such as intermetallic embrittlement). Sorry but the days of having a
"bright and shiny" solder joint are quick fading - they will totally
disappear when you begin utilizing a NoPb solder process. Having a "bright
and shiny" solder joint is not good reliability figure of merit - you would
be much better off using wetting angle and wetting geometries metrics.
Dave Hillman
Rockwell Collins
[log in to unmask]
"Brooks,Bill" <[log in to unmask]>@ipc.org> on 05/09/2002 02:09:54 PM
Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please respond
to "Brooks,Bill" <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
To: [log in to unmask]
cc:
Subject: [TN] Solder after reflow on Gold Immersion finish
I'm curious, has anyone seen the solder brightness become dull after reflow
when switching from HASL on the board finish to gold immersion? Any idea
how
to correct for it?
-Bill
-----Original Message-----
From: Furrow, Robert Gordon (Bob) [mailto:[log in to unmask]]
Sent: Thursday, May 09, 2002 10:59 AM
To: [log in to unmask]
Subject: Re: [TN] 63/37 solder paste with silver plated boards
Ron,
We routinely use eutectic tin lead solder paste with immersion silver
finished boards with no negative effects. The silver dissolves into the
molten solder pretty uniformly and the concentration is so low as to not be
relevant. The tin/copper intermetallic formation is essentially the same as
with HASL or OSP boards.
Thanks,
Robert Furrow
Printed Wiring Board Engineer
Supply Chain Networks
Lucent Technologies
978-960-3224 [log in to unmask]
-----Original Message-----
From: Vandendolder, Ron [mailto:[log in to unmask]]
Sent: Thursday, May 09, 2002 1:27 PM
To: [log in to unmask]
Subject: [TN] 63/37 solder paste with silver plated boards
Dear Technetters,
We would like to change from sn 62/pb/36/ag2 solder paste to standard tin
lead eutectic for silver plated boards. Does anyone know if there are any
issues with silver leaching that would force us to remain with the Ag
paste.
We started using the Ag paste years ago and now no one remembers why. The
silver plating on the boards is very thin (immersion 3-8 micro inches).
Regards,
Ron VandenDolder
Telaxis Communications
----------------------------------------------------------------------------
-----
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
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 delivery of Technet send e-mail to [log in to unmask]:
SET
Technet NOMAIL
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 1.8d
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 delivery of Technet send e-mail to [log in to unmask]:
SET
Technet NOMAIL
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 1.8d
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 delivery of Technet send e-mail to [log in to unmask]:
SET Technet NOMAIL
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 1.8d
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 delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL
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
---------------------------------------------------------------------------------
|
