Not sure about the etch rate but KI (potassium iodide) will etch nicely if your
device can tolerate the ions. I would avoid aqua regia if possible. It is
sometimes difficult to get photoresists to hold up well for long etches in it.

-Mike M.
 U. of Louisville

>>> [email protected] 11/30/05 8:33 AM >>>
Hello,

I'm trying to remove a 15 micron thick layer of gold over silica glass.  I have
some TFA old etch from Transene, but it takes a long time (1 hour) to do the job
- I would like to reduce the etch time to about 2-3 minutes.  Besides Aqua
Regia, what are the other solutions I could experiment with that could etch
faster?

I know aqua regia should do the job, but I would have to buy the nitric and
chloridric acids and I'm not sure which grades are best for this - any hints on
what acid concentrations and grades of HCl HNO3 to use in order to etch 15
microns of Au in 2-3 minutes?