Subject: | |
From: | |
Reply To: | |
Date: | Fri, 10 Oct 2008 09:34:54 -0400 |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
-----------------------------------------------------
Hi Paymon,
The root cause is ENIG 'Black Pad.'
In order to protect the electroless Ni from the immersion Au plating bath, P is codeposited.
As more and more Ni is dissolved during numerous soldering processes more P is left behind
weakening the interfacial structure--the more P, te weaker the interface.
Werner
-----Original Message-----
From: Paymon Sani <[log in to unmask]>
To: [log in to unmask]
Sent: Thu, 9 Oct 2008 9:57 am
Subject: [TN] PCB pad non-wetting issues
Hello All,
We are experiencing a pad non-wetting issue for the though-hole
component pads ONLY! The PCB goes through few heat cycles with top and
bottom side assembly during at SMT process and then through-hole
assembly at wave process. The problem is found at Wave process. The Pb
solder does not wet to the through-hole component pads on the solder
side only! An SEM/EDS evaluation revealed high concentration of P in the
Nickel and Nickel/Tin intermetalic layer of 11% to 21%. I would like to
ask anyone if they have experienced a similar defect in the past. What
is the Root Cause?
Thank you in advance,
Paymon
---------------------------------------------------
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
-----------------------------------------------------
|
|
|