We developed a solvent soluble polymer formulation in the late 1970's that  
could be applied to gold fingers prior to the soldering process. It had a 
UV  sensitive polymer in it that glowed under UV ("black light") inspection, 
so you  could check for complete coverage. The formulation interacted with 
the  co-deposited organics in the gold plating, so when the flux residues and 
the  gold finger protective coating dissolved in the solvent cleaner, the  
co-deposited organics were also removed. 
Comparative contact resistance measurements on incoming PWBs and completed  
assemblies clearly showed the contact resistance was much lower on the gold 
 fingers that had gone through the process. Black light inspection after  
soldering and cleaning showed that all the gold finger protection formulation 
 was removed. 
Papers were presented at NEPCON West on the technology by me (pp 565, 1980) 
 and G. J. Engelland (pp 228, 1981) and contained in the appropriate 
Proceedings.  The papers also describe the extension of the technology into a 
complete family  of solvent soluble manufacturing aids, including temporary 
solder mask, gold  finger masking and webbing spray to hold components in place 
prior to soldering.  All the materials were easily applied and automatically 
removed in the cleaning  step without additional labor costs. 
 


Bill  Kenyon
Global Centre Consulting
3336 Birmingham Drive
Fort Collins, CO  80526
Tel: 970.207.9586   Cell: 970.980.6373

 
 
 
In a message dated 5/21/2009 9:51:37 P.M. Mountain Daylight Time,  
[log in to unmask] writes:

Dear  all:
Anybody know that if there has  special method to clean the
golden finger's foreign matter or not. And if  there have some industry
standard indicate how to handle it?If can use the  IPA to clean the
golden finger or not? 
For  the protect method, we apply the Kapton tape cover the
golden finger before  build.

Best  Regards

Wang Rong

"This email is  confidential. Any unauthorized use or disclosure is 
strictly  prohibited."

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