Is the Dupont APG715 Dry Film fully aqueous? Are your holes completely dry 
 before you laminate the resist? I've seen wet holes before resist 
 lamination cause voids. The resist partially disolves and leaves a residue 
 on the hole wall that does not always develop out.


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Subject: Plated Through Hole Rim Voids
Author:  [log in to unmask] at corp
Date:    12/18/95 7:31 PM


We have experienced a random problem with three or four parts relative to rim 
voids.
 
In some cases it was part of the lot and in others it was the whole lot. 
 
They have been partial, full, top and or bottom. (no consistency) 
 
They are typically one to two mils down from the surface copper and one to 
three mils in height. 
 
They are not specific to any hole size. 
 
We use Dupont APG715 Dry Film, and develop on a Atotech/Chemcut horizontal 
system using Potassium Carbonate.
 
 
 
I would appreciate any suggestions, as to the cause.