I know of two etchants:
Hot (~160 C) 85% phosphoric acid, and 49% hydrofluoric acid.
Both require a mask other than photoresist, such as polycrystalline or
amorphous silicon.
See online papers for etch rates.
    --Kirt Williams

----- Original Message -----
From: "Sampo Tuukkanen" 
To: "MemsTalk" 
Sent: Thursday, September 23, 2004 8:11 AM
Subject: [mems-talk] Wet etching of silicon nitride?


> Hi,
>
> I would like to wet etch Si3N4 (LPCVD) to prevent the damages of silicon
> surface during RIE.
> BHF seems to be quite slow to that.
>
>
> Best regards,
>
> Sampo Tuukkanen, NanoScience Center, Jyväskylä.
>
> _______________________________________________
> MEMS-talk@memsnet.org mailing list: to unsubscribe or change your list
> options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk
> Hosted by the MEMS Exchange, providers of MEMS processing services.
> Visit us at http://www.memsnet.org/