Hi, all.
I am trying to etch the center area (2.5 inch diameter) of the backside of
500 um thick Si wafers (4inch diameter) using KOH wet etching process. I am
considering to use 300 nm LPCVD nitride to protect the edge area of the Si
backside. I am just wondering whether 300 nm thick nitride will be enough to
etch the center area of 500 um thick Si wafers.

Please let me know. Your help will be greatly appreciated.

Daniel