Hello Gabriela,
Yes, we have, but not in BGAs. In our case it was the source electrode
connection with the MESFET. We ran a lot of current + very high temperature,
got a too strong electron wind, which I suppose you've done too. We FIB'ed
the samples, only way to get indisputable images.
Inge
----- Original Message -----
From: "Gabriela" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, August 21, 2008 10:16 AM
Subject: [TN] Electromigration in solder bumps HELP!!
> Dear Technetters!
>
> I am sending these links because lately I performed cross sections with
> very
> similar results on a flip chip BGA which failed at our customer's site.
>
> As stated by our customer, by applying force on the component, the
> electrical results seemed to change, and the first supposition was that
> the
> solder joints between the BGA and the circuit had failed. X-ray results
> can
> not show cracks, but the re-reflow was not successful, and in the meantime
> a
> second identical component failed.
>
> I was given the first one for analysis and checked it by x-ray,
> separately,
> so that I had a much better image of the inner solder bumps. I found that
> the bumps had random voids.
>
> I started a very time consuming cross section of the bumps under the die
> and
> reached a region with voids under UBM and even melted bumps. The damaged
> bumps were random, and on the same row there were perfectly good ones.
>
> Question:
>
> Has anybody encountered such a problem?
>
> <http://www.jedec.org/download/search/JEP154.pdf>
> http://www.jedec.org/download/search/JEP154.pdf
>
>
> https://nscnt12.nsc.gov.tw/APPLYFORM/WRITINGS/L120452153/pb1-36.pdf
>
>
> http://www.imec.be/ngfcs/13_Labie_EM_public.pdf
>
>
>
>
> ---------------------------------------------------
> 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
-----------------------------------------------------
|
