The etch rate of SiN is about 1nm/min for room temperature BHF. For 180 nm SiN,
about 180 mins etching is needed. As far as I know, the photoresist will peel
off after such a long time in BHF. You can try the H3PO4 wet etching.

Regards!


2009-12-29
xudehui0108



发件人： Aleksandar Tomovic
发送时间： 2009-12-28  19:27:40
收件人： mems-talk
抄送：
主题： [mems-talk] wet etch of SiN revisited

Dear All,
i need to do a wet etch of SiN (don't have equipment for dry etch),i read that
it is  possible to do a wet etch with BHF, while using photoresist as etch
mask, but i also read somewhere that the photoresist will last only for a
short period of time (20 min). My SiN layer is 180nm thick. If anyone could
give me more data on this subject i would appreciate it.
Thanks in advance!

A.Tomovic