Address,
     
     I've found the recent discussions on Soldermask Residue interesting.  
     I've been faced with a similar problem and have investigated for 
     several weeks. After re-reading everyone's commments with information 
     I have, there are some discrepancies.  Would someone elaborate on 
     these items.  Again everyone has their method for each process, so 
     I'll leave names out.
     
     Which is correct items 1 or 2?
     
     1. Someone noted: Acid cleaners (pH 1 or micro-etchants; ph <1) would  
        remove some residual soldermask residues from the copper lands.
     
     2. OTHER:  Acid cleaners render soldermask residues insoluable, 
        in-turn "locking-in" soldermask onto the copper.  Alkalines are    
        recommended.
     
     My past experiences have been with item 2.
     
     Which is correct items 3 or 4?
     
     3. SERA testing can not detect chemical residues (i.e. soldermask      
        residue).
     
     4. SERA testing will detect chemical residues off a copper land.
     
     Please advise.  Thank you.
     
     John Gulley

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