I'd say it depends on the material mix of your structure. The standard for
SiN would be (hot) phosphoric acid. Because we use hydrofluoric acid for
many other process steps, we also remove SiN layers from pure si-substrates
with 5% aqueous HF which removes approx 1nm/min at room temperature.

Best regards,
Ben


-----Ursprüngliche Nachricht-----
Von: kapil kumar jain [mailto:kkjain2002@gmail.com]
Gesendet: Donnerstag, 24. März 2011 06:24
An: mems-talk@memsnet.org
Betreff: [mems-talk] Etching of SiN

What is the optimum concentration of SiN etchant ? The thickness is of
the order of 1000 A.