KOH tolerance of SiN

[masa]

Hi all,

I have a question about KOH tolerance of SiN by STS. I plan to use this
SiN as a mask for the Si etching in KOH. I'd like to etch through 400um
wafer. Since I heard this SiN is as bad as SiO against HF, I'm wondering this
may not be good to use long KOH etching. If you have any experience,
please let me know. I'm thinking to deposit SiN around 500nm thick.

Thanks.
Masafumi Nakamura