[thedoors24]

Hi,

I want to build up a microfabrication process that includes Ti, Au, Cu and In. In the process I need to wet etch the Ti and Cu with CR7 (Cyantek) and 10:1 (H2O and HF). The thing is that I will have to immerge the Indium layer in these two etchants. I know that HCL slowly etches Indium but I don't know if CR7 and HF do as well. I hope they don't.

Can you guys help me out?

Regards,
Xavier

[Arkcon]

I don't expect a weak acid like HF to affect a metal like iridium.  I don't recognize the trade item CR&, can you tell us what chemicals it contains?

[thedoors24]

First, it is Indium not Iridium  .

The CR7 composition is: Ceric Ammonium Nitrate 9% and Perchloric Acid 6%.

Thank you very much!

[Arkcon]

That makes the problem easier.   I have etched away the Inconel coating of a first surface mirror with 10% Ceric Ammonium Nitrate in 0.1 N Nitric acid, so the CR7 may attack it..

[thedoors24]

The coating of the mirror was made of Indium? Do you remember what was the etch rate? (slow, fast ?)

[Arkcon]

Opps, I went and checked, and it seems Inconel alloy contains no Indium.  Sorry about my confusion, but I guess I have no information for you.