I would bet the original problem was caused by "compromised"
 developing of the solder mask.   And there was soldermask 
remaining on the surface of the Copper.   I suspect that any 
repaired area would have the same problem.   Not knowing the 
process used to develop, I would venture to say that raising the
pH of the setting on the developer chamber (or improving rinsing)
would minimize or eliminate the issue.

Rudy Sedlak
RD Chemical Company


----- Original Message -----
From: TechNet <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Sent: Tue Nov 11 22:46:51 2008
Subject: [TN] Repair to ImAg plating?

Hi everyone,



We have an issue with loss of plating adhesion on some ImAg finished
PCBs.
The affected area is small and consistent in location across the PCBs
with
the defect.  All other areas seem to be ok when tested per a tape test.
The
PCB supplier is proposing to visit and "repair" them here at our
site.
I
was not even aware plating could be repaired, let alone away from a PCB
fab
shop without plating lines etc.  Is this even possible?  I am very
hesitant,
as I very seriously doubt the control and/or quality of the "repair"
process.  At the very least, how would thickness be controlled?  We
specify
micro 5-12 inches in thickness per IPC-4553, and the overall PCB is to
meet
IPC-6012 Class 3.

-----------------------------------------------------



      

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