Hi Hafizah,

Hot H3PO4 works on stoichiometric Nitride. Not on silicon-rich low-stress
nitride.
If you have 2um of Nitride, i suppose it is of the latter type?

Shivalik


> From: p.e.m.kuijpers@philips.com
> To: mems-talk@memsnet.org
> Date: Fri, 30 Oct 2009 15:42:32 +0100
> Subject: Re: [mems-talk] wet etch of 2um Si3N4
>
> Hello Hafizah,
>
> In here we also use hot H3PO4 (160°C).
> Etchrate on LPCVD SiN is app. 3nm/min
> Another method we use is etching in HF[48%], etchrate is also app. 4nm/min
>
> Regards,
>
> Peter Kuijpers