Carmen,
I use 133 grams of KI, 33.5 grams I2, in 150 cc H2O, to etch my Au on Cr.  I
sputter both films in the same system.  Have you tried to etch an Au film on
Si without the Cr?  Can you sputter etch a little of your Cr in the Au
system before sputter the Au?  Breaking vacuum between layers is never
desired.
Hope this helps,

Brent

Carmen wrote:

> Dear all,
>
> I faced the problem when I tried to use a KI/I2 mixture to etch gold. I
> am going to pattern the Cr and Au layers on the silicon substrate, and I
> used thermal evaporator to deposit the Cr and then sputter to deposit
> the gold. After depositing the gold layer by using sputter, I used a
> KI/I2 mixture to etch the gold layer. After etching for about 10 mins, I
> saw the gold was completely etched and there should be a shiny Cr layer
> under the gold layer after the wet etching. However, there is a cloudy
> thin film in light brown color appeared at the bottom of the gold layer
> and that layer cannot be etched in the gold etchant. I would like to
> know whether you have seen this problem before, and do you have any
> suggestion of the reason to cause this problem and what the layer is? Is
> that layer caused by some compound generated after the gold etching?
> Thank you very much!
>
> Best Regards,
> Carmen
>
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