What is the board/card surface finish? ENIG or OSP? I have seen similar growth on return samples which exhibit the whitish spots. I suspect a repair/rework site in which the flux residue was not completely burnt off, over saturated. What was their environment? Sulfur
Victor,
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Friday, July 06, 2012 11:19 AM
To: [log in to unmask]
Subject: Re: [TN] AW: [TN] Copper Dendrites
Hi Günter!
Got your pictures posted, they're here:
http://stevezeva.homestead.com/Dendrite_1.jpg
http://stevezeva.homestead.com/Dendrite_2.jpg
Steve
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Grossmann, Guenter
Sent: Friday, July 06, 2012 12:03 PM
To: [log in to unmask]
Subject: [TN] AW: [TN] Copper Dendrites
I sent the to Steve.
Cheers
Günter
>-----Ursprüngliche Nachricht-----
>Von: TechNet [mailto:[log in to unmask]] Im Auftrag von Victor Hernandez
>Gesendet: Freitag, 6. Juli 2012 17:55
>An: [log in to unmask]
>Betreff: Re: [TN] Copper Dendrites
>
>What happened to the pictures?
>
>Victor,
>
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of Paul Reid
>Sent: Friday, July 06, 2012 10:33 AM
>To: [log in to unmask]
>Subject: Re: [TN] Copper Dendrites
>
>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
>>
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