Hi,
    I am using a so-called Protek B3 layer (spin coated) from Brewer Sciences as
a protecting layer for my wafer frontside during KOH wet etching. It serves its
purpose pretty well, but it is very hard to remove. I tried the remover (Protek
remover 100) they suggested as well as acetone overnight.

There is still an apparent layer there after overnight soaking in above
solutions. I also tried to use O2 plasma (as well as CF4/O2 combination), but
with no apparent effect.  I am wondering if someone has any experience with it,
and would share their insight with me. By the way, my sample is on Si substrate
coated with a thin layer of SiN. The features are just metal.

Thanks

Xiaoyong