Dear all,

When I checked the references and found the etching rate of BHF is
100nm/min, if I wanna etch out 5 nm SiO2, just need 3 sec. That's too
short to operate.
Can I dilute the BHF to 1:10 concentration? Just using water to dilute it?
How can I check the etching rate for the diluted BHF?
Thanks for your help.

Best,
Jeff