Methodology for High Aspect Ratio PULSE PLATING

摘要

The potential of periodic reversed pulse (PRP) copper plating couldn't be ignored in 1999, when IBM Endicott began its design of a new copper plating line for manufacturing. It was decided that the line should incorporate pulse plating, but it was premature to commit all production to it. The ultimate design incorporated multiple smaller tanks, all of which could readily be converted to pulse, but only a few tanks were fitted upfront with the (more expensive) PRP rectifiers. Tank desing. Field studies provided no clear view of the best tank design - or the best source. Most data from suppliers had come from retrofitted DC tanks with whatever designs the customers had. Often the only changes that could be made were the cabling, rectifiers and bath chemistry, without any clear understanding of what "best practices" or optimal design would be. Some recommendations supported eductors; others pushed air agitation. Some promoted short anode-cathode distances; others suggested conventional spacing instead. Multiple inputs on cabling, rectifier suppliers and debates on square vs. complex waveforms had to be sorted out. Absent a clear consensus, experience and best-engineering assessments were the guides.