Question re. electroplated gold. Thank you

[lodgezhao]

Hello, I have a question for electrodeposition of gold.

So I tried to electroplate gold on a Si wafer with gold seed layer on it. I used SU-8 as my photoresist to form a pattern. But my electroplated gold was black and granular.

Area is 19mm^2 and desired thickness is 50 um. I set the effective current to be 1.9 mA.

Any ideas?

Thank you so much!

 

[Graniar]

1. Try to reduce current, 100A/m^2 may be too much for electroplating.
2. What kind of electrolite do you use? Normally, it should slightly dissolve gold to remove defects of growing layer.