Do you have a statistic numbers of PCBs failed out of batch size?
Do you have photos of cross sections
Do you have profile temperature and soldering technology (LF or Leaded)?

I had a customer with the same failure and I found it as a process failure.

You should send the failed PCB sample to an objective Lab. for checking the
P content and IMC photos.
Reuven

On Sat, Oct 22, 2011 at 9:57 PM, Joyce Koo <[log in to unmask]> wrote:

> Without knowing what speed he was talking about, my gut feeling is he might
> be using parts that intended to work at -20 to 85 but actually, bin 0 to 70C
> somewhere in the assembly (not necessary the memory he was talking about, as
> you suggest, might be the processor or other parts associated with).  My 1
> cents.
> --------------------------
> Sent using BlackBerry
>
>
> ----- Original Message -----
> From: Bob Landman [mailto:[log in to unmask]]
> Sent: Saturday, October 22, 2011 12:43 PM
> To: [log in to unmask] <[log in to unmask]>
> Subject: Re: [TN] High Phosphorous content on ENIG PCB
>
> Fabian,
>
> I would not jump to the conclusion it's a fab problem unless all electronic
> issues have been ruled out.  You say the SDRAM quits talking to the FLASH at
> -20C.  I don't understand that statement.  Memory doesn't talk to memory,
> the processor reads and runs code from the FLASH and writes and reads SDRAM.
>   Can the processor run at -20C?  If so then the next question is can the
> processor read and write to SDRAM?  Anything stuck on the data bus or memory
> bus (any other parts like ADC or DAC or display... ) can have a stuck bit.
>  An electronics tech should be able at -20C to tell which data or memory
> line or read/write line does not toggle when the test program exercises the
> lines.
> That will point you to which part (could be the processor) is not working
> correctly.
>
> Just my 2 cents.
>
> Bob Landman
> H&L Instruments
>
> Sent from my iPhone
>
> On Oct 18, 2011, at 12:30 AM, Fabien Guizelin <[log in to unmask]> wrote:
>
> > Bob,
> >
> > Thanks for the prompt support.    Some more info :
> > On failed PWA, the communication between SDRAM and FLASH stops at -20oC.
>   The units boots and hang or just refuses to boot.   Once temperature
> reaches back -10oC, the unit operates again.
> > Dye&pry showed potential poor joints on the balls but nothing conclusive.
> > We conducted EDX on both failed PWA and fresh PCB.  Both showed P-content
> 0.5% above IPC specs.
> >
> > Black-pad originates from high Phosphorous content.   But, how severe is
> 10.4%wt P-content ?
> >
> > Regards,
> > Fabien
> >
> >
> > From: Bob METCALF [mailto:[log in to unmask]]
> > Sent: Tuesday, October 18, 2011 10:07
> > To: TechNet E-Mail Forum; Fabien Guizelin
> > Cc: [log in to unmask]
> > Subject: Re: [TN] High Phosphorous content on ENIG PCB
> >
> > Fabien,
> >
> > It would be helpful to understand the nature of the failure. You mention
> it was a low temp failure. I don't understand what the failure is. Could you
> please expand on this? As far as the P content being slightly about 10%,
> assuming it is a mid to high phos nickel, I wouldn't expect a problem, but
> not knowing what has failed it would be difficult to speculate.
> >
> > Regards,
> >
> > Bob Metcalf
> > Western Regional Manager
> >
> > Atotech USA Inc
> > 1750 Overview Drive
> > Rock Hill, South Carolina 29730 USA
> >
> > Mobile: 714-334-7667
> > e-mail: [log in to unmask]
> > Internet: www.atotech.com<http://www.atotech.com/>
> >
> > Managing Director: Kuldip Johal
> >
> > This e-mail and any attachments hereto are business documents of Atotech
> USA Inc. and may contain CONFIDENTIAL OR PROPRIETARY BUSINESS INFORMATION.
>  Unauthorized disclosure and/or use of information contained in this e-mail
> are prohibited.  If you are not the intended recipient, you should dispose
> of it and not use, disseminate or copy this message or any other files
> transmitted with it.
> >
> > [cid:[log in to unmask]]
> >
> > .
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > From:        Fabien Guizelin <[log in to unmask]>
> > To:        <[log in to unmask]>
> > Date:        10/17/2011 05:42 PM
> > Subject:        [TN] High Phosphorous content on ENIG PCB
> > Sent by:        TechNet <[log in to unmask]>
> > ________________________________
> >
> >
> >
> > Hi all,
> > I am facing a PWA failure at low temperature.  An EDX analysis revealed a
> P-content of 10.4%wt which is outside the IPC-4552 1.2.1 specifications
> (7-10%).   The PCB has an ENIG finish.
> > Could I be facing black-pad ?
> > How severe is the 0.4%wt additional Phosphorous content ?
> > Regards,
> > Fabien
> >
> >
> > ______________________________________________________________________
> > This email has been scanned by the MessageLabs Email Security System.
> > For more information please contact helpdesk at x2960 or
> [log in to unmask]
> > ______________________________________________________________________
> >
> > ---------------------------------------------------
> > Technet Mail List provided as a service by IPC using LISTSERV 16.0
> > 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
> > For additional information, or contact Keach Sasamori at [log in to unmask] 847-615-7100
> ext.2815
> > -----------------------------------------------------
> >
> > ______________________________________________________________________
> > This email has been scanned by the MessageLabs Email Security System.
> > For more information please contact helpdesk at x2960 or
> [log in to unmask]
> > ______________________________________________________________________
> >
> > ---------------------------------------------------
> > Technet Mail List provided as a service by IPC using LISTSERV 16.0
> > 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
> > For additional information, or contact Keach Sasamori at [log in to unmask] 847-615-7100
> ext.2815
> > -----------------------------------------------------
> >
>
> ______________________________________________________________________
> This email has been scanned by the MessageLabs Email Security System.
> For more information please contact helpdesk at x2960 or [log in to unmask]
> ______________________________________________________________________
>
> ---------------------------------------------------
> Technet Mail List provided as a service by IPC using LISTSERV 16.0
> 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
> For additional information, or contact Keach Sasamori at [log in to unmask] or
> 847-615-7100 ext.2815
> -----------------------------------------------------
>
> ---------------------------------------------------------------------
> This transmission (including any attachments) may contain confidential
> information, privileged material (including material protected by the
> solicitor-client or other applicable privileges), or constitute non-public
> information. Any use of this information by anyone other than the intended
> recipient is prohibited. If you have received this transmission in error,
> please immediately reply to the sender and delete this information from your
> system. Use, dissemination, distribution, or reproduction of this
> transmission by unintended recipients is not authorized and may be unlawful.
>
> ______________________________________________________________________
> This email has been scanned by the MessageLabs Email Security System.
> For more information please contact helpdesk at x2960 or [log in to unmask]
> ______________________________________________________________________
>
> ---------------------------------------------------
> Technet Mail List provided as a service by IPC using LISTSERV 16.0
> 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
> For additional information, or contact Keach Sasamori at [log in to unmask] or
> 847-615-7100 ext.2815
> -----------------------------------------------------
>



-- 

Best Regards,

*Reuven Rokah*

Mobile: 972-52-60-120-18
Tele-fax: 97239360688
<http://www.rokah-technologies.com/>[log in to unmask]
[log in to unmask]
www.rokah-technologies.com

**
This e-mail message is intended for the recipient only and contains
information which is CONFIDENTIAL and which may be proprietary of Rokah
Technologies. If you have received this transmission in error, please inform
me by e-mail, phone or fax, and then please delete all of the original files
and all other copies exist.


______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 16.0
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
For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------