On Tue, 17 Sep 2002 17:23:00 -0700, Peter Lee <[log in to unmask]> wrote:

>Technet,
>
>If I may continue my question on BGA rework process:
>
>Recently we have seen intermitted failures from a few BGA assemblies.
>After removing the suspicious BGA on the rework station we noticed
>dewetting on a majority number of pads of the removed BGA. The solder
>ball residues were mostly attaching to the board.
>
>Has anyone seen this before? How likely can this be caused by a
>non-optimum rework removal profile Is baking of the board normal prior
>to rework (removal/re-placement)?
>
>We are tackling this issue from the part supplier side and looking at
>performing destructive X-ray analysis. Can someone give me an idea of
>what the ball attachment process is on the BGA?
>
>Rgds,
>Peter
>
>---------------------------------------------------------------------------
------
>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
>---------------------------------------------------------------------------
------

I saw your post on the list and it resembles some problems we've had here
with BGA's. I have a question, do the dewetted pads on the components look
dark? ("Black pads")

Rgds
Tore

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