It appears to be inside - it doesn't clean off.
 


Kevin Glidden
Manufacturing Engineer
Luminescent Systems Inc.
4 Lucent Drive
Lebanon, NH 03766
(603) 643-7766 x3152
 

-----Original Message-----
From: Ian Hanna [mailto:[log in to unmask]] 
Sent: Friday, September 28, 2007 10:07 AM
To: TechNet E-Mail Forum; Kevin Glidden
Subject: RE: [TN] Copper Staining in PCB laminate

IS this staining on the surface of the laminate or does it appear to be
inside.  Is there any indication of residue on the copper surface.  My first
guess would be pigment from the black solder-mask, but that's just a first
guess...Ian

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Kevin Glidden
Sent: Friday, September 28, 2007 9:06 AM
To: [log in to unmask]
Subject: [TN] Copper Staining in PCB laminate

We recently received a shipment of PCBs where the exposed outer layer
laminate has staining that looks like copper. I have a photo -
<http://tinyurl.com/yp9za2> http://tinyurl.com/yp9za2 My question is what
would cause this?  I've never seen it before, but I am thinking something in
the Copper plating process.  The vendor is telling us it is staining but it
is an asthetic issue only. What would cause it?
Is it
an asthetic issue only?  It seems to me if the staining was caused by some
plating chemistry, then it would effect the laminate properties,
particularly the insulation resistance.
 
Thanks!
 
Kevin Glidden
Manufacturing Engineer
Luminescent Systems Inc.
 
 
 

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