\0
   TO:         I4235700 IBMMAIL   new address for ipc technet 25.6.96

   FROM:       DSTEWART EX2       D.Stewart        - Product Development Manager.

   DATE:       7 October 1997
   SUBJECT:    YTECHNET? IMMERSION AU, NPTH DEPOSITS

    David, what you are seeing is ENAu depositing onto the palladium
    residues from the original electroless copper process, left in the
    holes after etch and tin strip. If your boards are soldermasked
    prior to ENAu, the temperature of stoving 'fixes' this palladium
    deposit and it cannot be 'poisoned' by the preactivation stages of
    the ENAu line. We had to do all over ENAu for a long time because
    of this problem, but by working with our chemistry supplier, we no
    longer have an issue. The reason why you don't see it on the
    drilled after plate holes is because they never had palladium in to
    start with.

    Dougal Stewart
    Viasystems, Selkirk

##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TECHNET <your full name>
To unsubscribe:   SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information.
For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311
##############################################################