---------------------------- Forwarded with Changes --------------------------- From: [log in to unmask]@INTERNET at #EMAIL Date: 2/12/97 1:32PM To: Misri Mohd RSB019 at ZMY04_CC03 *cc: [log in to unmask]@INTERNET at #EMAIL *cc: [log in to unmask]@INTERNET at #EMAIL Subject: Re: Discolouration in Electrochemistry ------------------------------------------------------------------------------- I'm working with Semiconductor reel-to-reel solder plating process. It is Solder over copper plating process. Among the problem that we face is "Discolouration", whereby the plated products change colour from shining white to gray, bluish or black marks. This situation normally occure during production line stoppages. What we observe is that chemical remain on the parts for extended period lead to oxidation process. Our process flow is something like this Cathodic stripping----->Anodic stripping---->acid Activation--> --->solder plating--->rinsing. Those parts remain in acid Activation and solder plating are the most critical. Some of the thing that i tried were 1)to immediately rinse the part when the production stop. The problem is that, the water rinse dilute the plating solution. 2)Reverse plating or deplate and plate. -Revese the cathode/anode polarity. The solder will be strip out during line stoppages. Then replate again. This method fail soldaribility due to not sufficient pre-cleaning and copper contamination. Do you have any opinion on this? Any other suggestion to resolve this problem? regards Mohamed Misri ISMF Seremban, Malaysia *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************