Nick,

     You need to determine the source of the discoloration and eliminate
     it.  Is it present right after immersion gold?  Could be poor rinsing
     or drying or both.  Do boards get soldermask before or after immersion
     gold?  If after, it could be mask or developer residue.  Are boards
     handled with bare hands or gloves after gold?  Should always handle
     immersion gold product with clean gloves, rack only, do not lay flat
     and slipsheet.

     A dip in a soap cleaner such as Morton's LAC-91 does wonders for
     cleaning up fingerprints and water stains from soft gold.  However,
     you must get a thorough rinse and sufficient drying or you just get
     more water stains after.

     Hope this helps...Andy


______________________________ Reply Separator _________________________________
Subject: [TN] Pad Discoloration???
Author:  Nick Liang <[log in to unmask]> at smtplink-hadco
Date:    06/04/99 11:17 AM


All:
One question about the Pad Discoloration Spec. (Immersion Gold pcs...)!!

I don't think the IPC has the Spec., right?
Is it required to use acid rising after the E/Test and FQC inspection???

You know, right now we just use the water rinse and 120mins baking
right after the Routing Process and then E/Test, FQC, OQC and Packing.

A lot of Pad Discoloration Quality Issue Feedback recent time!!!!

THKS.

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