Hi all TN,

     Solder on gold finger has existed in our factory for a long time. We
     have put a lot of efforts to tackle it, but the result is still
     unsatisfactory. We have done several kind of experiments in order to
     investigate the source. We have checked the incoming PCBs and our
     process prior to do testing. All the PCBs were cleaned with Ultrasonic
     bath and visual inspection using 40x microscope before conducting
     experiment.

     The problems are:
     1. the gold plating PCBs (no HASL)appeared solder on G/F after
     reflowed under bare condition.

     2. all via holes are plugged on HASL PCB but solder on G/F still saw after
     reflow.

     3. Gold fingers are covered with tape and then reflow but still happens
     this problem.


     Does anybody have such experience? Any feedback would be appreciated.

     Best Regards,

     Poon Man

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