MEMS microphone

Abstract

The invention provides an MEMS microphone. A cavity is defined by a support wall body on a substrate, a vibrating diaphragm is suspended in the cavity, and the edge of the vibrating diaphragm extendsinto the support wall body to realize fixation. A release hole array on aback plate structure comprises a plurality of release holes which penetrate through the back plate structure and are communicated with the cavity, and in the process that the sacrificial layer is released through the release hole array to form the support wall body, the outline of the inner wall of the support wall body can follow the outline of the side, close to the support wall body, of the release hole in the outermost ring. The second side, back to the center of the release hole array, of the outermost circle of release holes in the release hole array is arranged to be flatter than the first side, facing the center of the release hole array, of the outermost circle of release holes, so that the outline of the inner wall of the wall is smoothly supported, sharp corners are inhibited from forming, the sharp corners are prevented from puncturing the vibrating diaphragm to cause falling of the vibrating diaphragm, and the service life and reliability are improved.

Description

technical field [0001] The invention relates to the technical field of micro-microphones, in particular to a MEMS microphone. Background technique [0002] The MEMS microphone is a MEMS (Micro-Electro-Mechanical System, Micro-Electro-Mechanical System) device manufactured by a micro-machining process. Due to the advantages of small size, high sensitivity, and good compatibility with existing semiconductor technologies, MEMS microphones are more and more widely used in mobile terminals such as mobile phones. [0003] The structure of the MEMS microphone has a vibrating membrane, a backplane structure and a supporting wall. The supporting wall forms a cavity B', the backplane structure is located on the supporting wall and covers the cavity B', and the vibrating membrane is suspended in the cavity B' And the edge extends into the supporting wall 200' for fixing. figure 1 Schematic diagram of the structure of the existing supporting wall 200', such as figure 1 As shown, in t...

AI Technical Summary

Problems solved by technology

figure 1 Schematic diagram of the structure of the existing supporting wall 200', such as figure 1 As shown, in the manufacturing process of the MEMS microphone, the supporting wall 200' is formed by releasing the sacrificial layer using the release hole array on the backplane structure (the etchant uses the release hole array as a channel to corrode part of the sacrificial layer, and the remaining The sacrificial layer forms the supporting wall 200', and the corroded part forms a cavity B'), resulting in that the contour of the inner wall of the supporting wall 200' is not smooth, but wavy, and has sharp corners Q in the wavy shape, due to the vibration The membrane needs to vibrate up and down in the cavity B', and the edge of the vibration membrane is fixed by the supporting wall 200'. During the vibration of the vibration membrane, the sharp corner Q is easy to pierce the vibration membrane, which will cause the vibration membrane to break and even fall from the support wall. Body 200' falls off, causing damage to the device

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