Dear Group,

When I am doing Si etching by KOH 45%wt(80C), I coated thermal oxide as a
etchmask.
First, the Si etchrate is about 40 um/hr.It seems lower than others(60 um/hr).
Second,the oxide etchrate is about 1 um/hr,  much higher than others(80 nm/hr).
Is that normal ?

Thank you.
Sincerely,
Nick Lin