Ah, Now I understand.

Conductive filaments can grow particularly conductive anodic filaments.
I was thinking of a dendrite of copper not conductive filaments. I
expect dendrites to be larger and of pure copper but you may get
dendritic growth with a contaminate, in the presents of water and with
an electrical potential.

Sorry for my misunderstanding.

Sincerely,  

 

Paul Reid 

Program Coordinator  

PWB Interconnect Solutions Inc. 
235 Stafford Rd., West, Unit 103 
Nepean, Ontario Canada, K2H 9C1 

613 596 4244 ext. 229  

Skype paul_reid_pwb 
[log in to unmask] 

 


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Guy Ramsey
Sent: July 6, 2012 9:23 AM
To: [log in to unmask]
Subject: Re: [TN] Copper Dendrites

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


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


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

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