Hi, I am looking for some commercially available (or maybe I have to make it myself) wet etchant for Si3Ni4 film using photoresist as mask (protect some area). I heard that some people are using H3PO4. If it's true how is the composition ratio. (Al film can be etched by H3PO4, right ? what is the difference )? Can anybody provide some detail information ? Thanks for your help Gu