Try tin immerse or even a thin coating of oxide on one panel.
     If you suspect surface contaminates, this is a simple easy test
     that can be stripped off. If your problem is tape residue, good luck.
     That's a hard one to get rid of. (Until you remove the tape variable)
     
     Groovy
______________________________ Reply Separator _________________________________
Subject: Exposed copper after electroless nickel gold
Author:  [log in to unmask] at SMTPLINK-HADCO
Date:    4/25/96 9:22 AM


Recently we encounter exposed copper problem after electroless nickel gold 
process ,
we wish to know if there any way to determine the stubborn film on top of 
the copper
that prevent the plating to take place . We understand that soldermask on pad or
poor rinsing after final development could give rise to such problem . Such 
problem
of soldermask on pad could be easily found after HAL but cases of minor 
soldermask
on pad could not be detected in HAL . Please advise .