\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 ##############################################################