Hi, all. We are having a sandwich structure- bottom substrate is Si, middle is
SiO2(10nm), top is Cr/Au(200nm).

we would like to etch away the middle SiO2 layer. Is it possible if we dip it in
HF or BOE? Since the solution can only touch the side (10nm, very thin), I am
afraid it will not separate the sandwich completely.

Any suggestion is appreciated!

Thanks.