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Leaching Test Failure on Terminal

I am from a chip resister manufacturing company and we implement auto barrel PLC plating system. Recently I face the difficulties to plate Nickel on Ni-Chrome layer material (0.1 micron of combination 50% Ni and 50% Chrome sputtering layer and the base material is Alumina Ceramic substrate). Our processes are cleaning, acid activation by 5% sulfuric Acid, Nickel plating, rinsing, 5% MSA acid activated, rinsing, Solder plating.

We found some chips(50 pieces out of 1000 pieces) fail leaching test.(No coverage and some poor coverage) and we measure the failed area by XRF found no nickel thickness. I'm trying few actions, e.g.: increase Ni plating current, increase acid activator concentration from 5% to 10%,increase Ni metal concentrations but the problem still happens and randomly.

K.C.LOO
- Johor Bahru, Johor, Malaysia
2003

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It sounds like you have move of a mixing problem than chemical problem. Questions you should ask yourself are: Do I have the right chip to media ratio? Has the media been sized for the chip size? Are the barrels being over loaded? The company I worked for used to sort non-plated chips out with a magnetic. Another thing to look at is to be sure that parts are wetted in the etching process and don't float in the barrel. You may have to add a wetting agent.

Good luck!

Karl Weyermann
- Lebanon, Kentucky, USA
2003