Hi,

how do you deposit the silicon nitride?
It should be LPCVD in order to avoid etching in KOH bath.

Hope this helps,

Jordi


On 5/21/07, Andrea Mazzolari  wrote:
> Hi all,
> i deposited about 20nm of silicon nitride on a silicon wafer.
> After patterning silicon nitride, i etched silicon in KOH (20%) at 100°C.
> After about 2 hours etch, silicon nitride was completely removed!
> I always knew silicon nitride perfecly mask against KOH etch!
> What could be happened ?