I agree. I have seen dendrites grow under solder mask from on conductor to
another, and from a PTH to a conductor, under solder mask. 

If the residue were benign, until exposed to water, and the coating were to
protect it from exposure, it could help.

Still, I am skeptical, that it would reduce risk of failure. It would need
to be a designed process, not a band aid.

It might make things worse.

Guy

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Graham Naisbitt
Sent: Friday, July 06, 2012 8:23 AM
To: [log in to unmask]
Subject: Re: [TN] Copper Dendrites

Hi Neil

I stand by my earlier posting on this. Neither a solder resist nor a
conformal coating will PREVENT dendrites, they might delay it for a while,
but then what is lurking and festering underneath..just when you thought it
was safe to go back in the water!?

Graham Naisbitt


On 5 Jul 2012, at 19:50, Neil Atkinson wrote:

> Thanks everyone for comments so far - haven't been on Technet for a while
so it was good to get such good responses.
> 
> Really miss Werner for questions like this...
> 
> Actually we have never seen a failure for dendrites; however, we have a
customer who has a past problem with another supplier due to dendrites on
PCBs and as a result wants us to cover vias with solder resist or conformal
coating.
> 
> Tha,
> 
> Neil
> 
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