Ta wet etching

Hi,

I was wondering if anyone has experience with wet etching of thin Ta
films. I only need to etch 5 nm and I don't mind a slow etch rate.
Most references I found online recommend using a concentrated solution
of HF and HNO3 but I would prefer something milder, especially since I
am not looking for a high etch rate.

Thanks a lot,
Arunanshu