Harvey

Prior to the introduction of immersion silver into AT&T (at the time)
extensive work was done to convince Telcordia there were no migration
issues. This work was presented at a SMT conference in 96 (I believe) by
George Wenger and Bob Furrow. The results were unambiguous; there was no
evidence of migration.

Best regards

Lee

J. Lee Parker, Ph.D.
JLP Consultants LLC
804 779 3389


----- Original Message -----
From: "Harvey Miller" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Saturday, August 19, 2006 2:28 PM
Subject: [LF] Silver Migration


> Subject: Re: another dendrite question
> Date: Thu, 17 Aug 2006 12:44:29 +0100
> From: John Woodgate <[log in to unmask]>
> Organization: J M Woodgate and Associates
> Newsgroups: sci.electronics.design
> References: <[log in to unmask]>
>
> In message <[log in to unmask]>, dated Thu,
> 17 Aug 2006, Jeff_M <[log in to unmask]> writes
>  >I understand that to prevent silver migration between pads on a circuit
>  >board with a silver immersion finish it is necessary to have solder
>  >mask between the pads.  Is this true?  How much solder mask?
>
> I've seen silver migrate across 2.5 mm of a glass seal, with 5 V driving
> it. Enough conductivity for the affected device to show as a
> short-circuit.
> --
> OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk
> 2006 is YMMVI- Your mileage may vary immensely.
>
> John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
>
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