Hi all,

I have fabricated copper inductors using through-photoresist electroplating..
50 nm Cr with 300 nm Au layer is used as seed layer. Thickness of copper
metal lines if about 4 microns and pitch between two metal lines is about 15
microns.

Now i want to etch seed layer without affecting the copper metal lines. i
have used KI+I2 solution to etch gold, however i have found that some copper
metal lines are also etched away and copper electroplated surface has become
rougher. It seems that this gold etchant has not good slectivity with
copper.

Can any one suggest some etchant/methods using which, Cr/gold seed layer can
be etched away without affecting copper lines.

Thanks,
Pradeep Dixit