Letter 40091

Leveled rhodium for electronics industry  

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Hi...I'm trying to get information on how to achieve bottom up plating or "superfilling" of small via structures. Has anyone used additives in Rhodium bath to accomplish this?

David Clarke
electonics mfgr - Beaverton, Oregon

I haven't heard of anything but copper being used for that yet, David. Hopefully, someone else has.

Ted Mooney, P.E.  finishing.com Brick, New Jersey

Try Pulse plating ... you have to play around with duty cycle to get the desired fill. Normal Forward pulse will do, but reverse pulse will be a better option too.

Karthik Thambidurai
- Austin, Texas