MEMS microphone and method for forming the same

The present invention discloses an MEMS microphone and method for forming the same, wherein the method for forming the MEMS microphone comprises: providing a wafer with a conductive plate on a front side thereof, the conductive plate including a vibration region and a support region; forming several through holes in the conductive plate in positions corresponding to the position of the vibration region, and forming a first sacrifice layer on the conductive plate and in the through holes; forming several grooves in the first sacrifice layer in positions corresponding to the position of the support region, the grooves passing through a side wall of the first sacrifice layer; forming a second sacrifice layer in the grooves; forming a vibration membrane on the first and second sacrifice layers; forming a back cavity on a back side of the first wafer in a position corresponding to the position of the vibration region; and removing the first and second sacrifice layers in positions corresponding to the vibration region. Air in the gap of the MEMS microphone is exhausted through the grooves, which reduces the damping for sound propagation from air so that acoustics energy reaching the vibration membrane is high. Therefore, the sensitivity of the MEMS microphone is improved, such that the MEMS microphone has better performance.