MEMS microphone, micro-electromechanical structure and manufacturing method thereof

Abstract

The invention discloses an MEMS microphone, a micro-electromechanical structure and a manufacturing method thereof. The micro-electromechanical structure includes: a first back polar plate having a first through hole; a second back polar plate provided with a second through hole and positioned on the first back polar plate; a vibrating diaphragm located between the first back polar plate and the second back polar plate, wherein the vibrating diaphragm and the first back polar plate form a first variable capacitor, and the vibrating diaphragm and the second back polar plate form a second variable capacitor; a first protective layer, wherein the first protective layer and the vibrating diaphragm are positioned on two sides of the first back polar plate respectively and are used for preventing foreign matters from entering a gap between the first back polar plate and the vibrating diaphragm through the first through hole; a second protective layer, wherein the second protective layer andthe vibrating diaphragm are positioned on two sides of the second back polar plate respectively and are used for preventing foreign matters from entering a gap between the second back polar plate andthe vibrating diaphragm through the second through hole; and a second connecting part positioned on the surface of the second back polar plate and fixedly connected between the second protective layerand the second back polar plate, so that the second protective layer is separated from the second back polar plate.

Description

technical field [0001] The present application relates to the field of semiconductor device manufacturing, and more specifically, to MEMS microphones, micro-electromechanical structures and manufacturing methods thereof. Background technique [0002] Devices manufactured based on Micro Electro Mechanical Systems (MEMS) are called MEMS devices. MEMS devices mainly include a vibrating membrane and a back plate, and there is a gap between the vibrating membrane and the back plate. The change of air pressure will cause the deformation of the vibrating membrane, and the capacitance value between the vibrating membrane and the electrode plate will change, which will be converted into an electrical signal output. [0003] In the traditional MEMS microphone structure, it is mainly composed of two parallel plate capacitor structures, the back plate and the vibrating membrane. When the chip size is determined, the performance improvement is limited. Output signal, but this will intro...

AI Technical Summary

Problems solved by technology

[0003]In the traditional MEMS microphone structure, it is mainly composed of two parallel plate capacitor structures, the back plate and the vibrating membrane. When the chip size is fixed, the performance improvement is limited , in order to improve the signal-to-noise ratio of the microphone, the differential output signal of the double back pole microphone structure is adopted, but this will introduce a problem. Such as dust particles, water, oil, etc., if these foreign objects enter the gap between the vibrating membrane and the back plate, these foreign objects can easily cause a short circuit between the vibrating membrane and the electrode plate, and then make the MEMS device fail

At present, most of the solutions in the industry to solve such problems are to introduce dust-proof materials on the back side of the package. This kind of dust-proof materials and processing costs are high, and it only plays a dust-proof role on the back of the MEMS microphone, and there is no protection on the front.

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