Subject: | |
From: | |
Reply To: | |
Date: | Wed, 5 Sep 2007 11:21:26 -0400 |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
Gil
I am dubious that this is a CAF failure. CAF failures have specific
earmarks. They are cause by operating a board in a very high humidity
environment at the board surface.
This is normally precluded because of the heat generated by the board which
drives the local humidity to a low value even if the ambient humidity is
high. The defect is by definition a growth that originates at the anode and
eventually reaching a cathode.
I suspect that a conductive residue was present in or on the innerlayer that
eventually caused a short to form between adjacent features. Some of the
causes that I have seen for such a failure are: poor cleaning after etch,
conductive residues such as human hair entrapped between layers and moisture
in the innerlay and prepreg which eventually cause a short.
Best regards
Lee
J. Lee Parker, Ph.D.
JLP Consultants LLC
804 779 3389
----- Original Message -----
From: "Zilber Gil" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, September 04, 2007 1:25 PM
Subject: [TN] Help needed on motherboard failure analysis
> Hi,
>
> Recently one of our motherboard failed. It reaches very high temperature
> that melts the copper and explodes shooting (from the side of the board)
> the melt copper to over 20 cm. the shooting hole cause delamination of
> the board in the area. A lot of black smoke and was also seen. The max
> voltage of the board is about 50V. The board worked fine for more then a
> year. What could be the failure mechanism? Could it be due to conductive
> filament formation (although the PCB should be free of that)?
>
> Thanks
>
> Gil Zilber
> Elta Systems
>
> The information contained in this communication is proprietary to Israel
> Aerospace Industries Ltd.
> and/or third parties, may contain classified or privileged information,
> and is intended only for
> the use of the intended addressee thereof. If you are not the intended
> addressee, please be aware
> that any use, disclosure, distribution and/or copying of this
> communication is strictly prohibited.
> If you receive this communication in error, please notify the sender
> immediately and delete it from
> your computer. Thank you.
>
>
> This message is processed by the PrivaWall Email Security Server.
>
> ---------------------------------------------------
> 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
-----------------------------------------------------
|
|
|