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Setting up Electroplating Bath

I am currently setting up an experiment to electroplate a pattern in photoresist on fused silica wafers. The electroplated metal will be used as a mask, and therefore needs to fill in the grooves, but does not need to have a perfect level finish. I was wondering if anyone had advice for setting up a bath: power supply, electrodes, plating solutions, additives, etc. I will probably be trying different metals: currently Cu or Ni, and also need to know what type of seed layer is preferred.

Julie Jay
- Waitsfield, Vermont, USA
2002

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You are actually setting up something very similar to an electroforming process, so you will need a low stress electrolyte with good throwing power. The power supply will be dependent on the size of the workpiece, but tank filtration is critical for good replication. I would personally recommend up to 10 tank turnovers per hour and careful electrolyte composition control. Depending on the size of your pattern you may need a clean room type environment - if you are replicating grooves of 10um, you don't want a 20um particle landing on the pattern as it will destroy the replica. The best metals for this work are probably nickel or copper; preferably based on nickel sulphamate and copper cyanide respectively. If you are rich, you can use silver or gold cyanide solutions.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2002