LithoTalk

[Jhon]

What is the best sulotion to etche Si3N4

[Guest]

Do you want to etch the Si3N4 wet chemically? In this case, BOE (buffered hydrofluoric acid) is a good choice. Do you want to use a photoresist etch mask for this process? If yes, you would have to consider two main points:

1) The adhesion of photoresist on Si3N4 is often very poor - maybe an extended softbake or a hardbake after development (e.g. 140?C for 5-10 minutes) will help a little bit.

2) Etching with HF-containing media is often accompanied by a lift-off of the resist film during etching or the subsequent rinsing, caused by the permeability of HF in resist causing swelling of the resist and etching under the resist mask. In this reason, a thicker resist film is very beneficial.

Hope this helps a little bit!