Structure of micro-electro-mechanical-system microphone and method for fabricating the same

A method for fabricating MEMS microphone, comprising:

• providing a substrate;
• forming a dielectric layer on the substrate, wherein a membrane is embedded in the dielectric layer;
• forming an electrode layer on the dielectric layer, wherein the electrode layer has a plurality of first openings and a plurality of second openings over the membrane, wherein the second openings are distributed surrounding the first openings;
• forming an indent in the dielectric layer within each of the second openings of the electrode layer;
• forming a protection layer, covering on the electrode layer to form a backplate layer, wherein a portion of the dielectric layer with the indents within the second openings are also covered by the protection layer while a portion of the dielectric layer within the first openings of the electrode layer is exposed by the protection layer, and wherein the protection layer is formed on the top surface of the dielectric layer and not in contact with the substrate;
• forming a first electrode structure in the dielectric to contact the membrane and a second electrode structure on the protection layer to contact the electrode layer;
• patterning the substrate to have a substrate opening corresponding to the membrane to expose the dielectric layer;
• and
• etching a portion of the dielectric layer corresponding to the substrate opening to expose a portion of the membrane,
• wherein the electrode layer is also exposed and a portion of the protection layer within the second openings of the electrode layer is also exposed to form anti-sticky structures, and the anti-sticky structures as formed are distributed at an inner region within the electrode layer and an outer region out of a periphery of the electrode layer.