Mems microphone structure and method of manufacturing the same

A method of manufacturing a MEMS microphone structure comprising the following steps:

• forming a first dielectric layer, a lower diaphragm electrode and a second dielectric layer successively on a substrate;
• performing lithography and etching processes to form an annular trench, at least a part of the bottom of which extending to the lower diaphragm electrode while the rest of the bottom of which extending to the substrate, wherein an area enclosed by an inner sidewall of the annular trench forms a back plate region;
• depositing a first insulating layer, wherein the first insulating layer filled in the annular trench forms an annular supporter;
• depositing an upper electrode and patterning to form a patterned upper electrode covering at least a part of the first insulating layer within the back plate region;
• depositing a second insulating layer;
• forming an upper electrode connection and a lower electrode connection;
• etching to form multiple holes penetrating the first insulating layer and the second insulating layer within the back plate region to form a back plate;
• forming a cavity extending through the substrate, the top of which is within the area enclosed by the inner sidewall of the annular trench;
• and
• performing releasing process to remove the first dielectric layer and the second dielectric layer within the back plate region and above the cavity together, so as to form an air gap between the back plate and the lower diaphragm electrode.