Hi, everyone,

Can anybody please tell me how to improve the sticking of PMMA on Si O2
surface? I am trying to etch a trench of ~50 nm wide and 15 nm deep in
the SiO2 layer using HF but the PMMA lift off from the surface when I
dip the wafer into HF solution.Any comment is greatly appreciated.

Thanks.

Jie Liu
Rice University