We use Scherring-Atotech high build chemistry for chemical copper and their GS818 additive brightener system for electrolytic copper plating for the last couple of years. Right from the beginning we have been observing tiny nodules in the through holes after doing 25 micron galvanic copper plating. No nodules are observed at the the high build electroless stage when the built up chemical copper is just 2 to 2.5 micron. There have been lot of back and forth visits by the vendors application staff and plus our own process engineers attempt to get over the problems but none of which has met with any significant success.We have tried out the following: 1 Thorough inspection of drilled holes and complete removal of epoxy dust through high pressure reciprocating water jet cleaning at brushing stage. 2 Transfering the electroless solution into another clean tank before commencing electroless. 3 Continuous filteration of electroless copper bath at the rate of 2000 litres per hourmaintained. 4 Optimum temperature and concentration of various baths maintained by periodic additions. 5 Close monitoring of brightener additions in electrolytic copper bath as per ampere hour. 6 Current density lowered to 2 amps to 2.5 amps per decimetre square for longer duration to eliminate the possibility of burning. None of the above have yielded any significant improvement. Suggestions invited. Thanking in advance. P. V. Khan Chief Quality Manager Linaks Microelectronics Ltd e-mail: [log in to unmask] *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * 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] * ***************************************************************************