For wet etching of silicon nitride, the standard etchant phosphoric acid,
heated to around 160 C. This is hard to mask however.

PECVD nitrides can be etch with HF solutions. I suggest 5:1 BHF for its
stability.
The etch rate will vary with the composition. I have measured 8-60 nm/min
for different PECVD recipes. BHF can be masked with photoresist.

For dry etching, both CF4 + O2 and SF6 + O2 plasmas work,
and can be patterned with photoresist (but the selectivity may not be good).

        --Kirt Williams, Ph.D.  Consultant

> -----Original Message-----
> From: Patrick Carlberg [mailto:[email protected]]
> Sent: Thursday, March 13, 2003 1:15 AM
> To: [email protected]
> Subject: [mems-talk] Etching of SiN
>
>
> Dear all,
>
> Could anyone tell me how what to use for dry and wet etching of SiN
> grown in PECVD (So there is probably some H in ther as well)
>
> Thanks
> Patrick Carlberg
> __________________________________________________
> Patrick Carlberg, Ph.D Student, MSc
> Lund University, Solid State Physics/Nanometer Consortium
> Box 118, SE-221 00 LUND, Sweden
>
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