MEMS microphone

This application claims the priority benefit of Chinese Patent Applications Ser. No. 201820210098.7 filed on Feb. 6, 2018, the entire content of which is incorporated herein by reference.

The present disclosure relates to electro-acoustic conversion field, and in particular, to an MEMS microphone.

In recent years, mobile communications technologies have developed rapidly. Customers use mobile communications devices more frequently, for example, a portable phone, a portable phone that can access the Internet, a personal digital assistant, and other devices performing communication by using a dedicated communications network. A microphone, especially a micro-electro-mechanical system (MEMS) microphone, is one of the most important components in mobile communications devices.

The MEMS microphone is an electric transducer manufactured by using a micromechanical processing technology and has features such as a small volume, a good frequency response feature, and low noise. As electronic devices become smaller and thinner, MEMS microphones are widely applied to the devices.

An MEMS microphone in the related art includes a substrate having a back cavity and a capacitor system fixedly disposed on the substrate. The capacitor system includes a backplane and a vibrating diaphragm that are spaced apart from each other. The backplane includes a backplane insulation layer and a backplane conducting layer disposed on the backplane insulation layer.

However, in the related art, an outer edge of the backplane conducting layer is flush, an outline of the outer edge of the backplane conducting layer does not pass through any backplane hole. In an MEMS processing process, a crack occurs at a boundary between the backplane conducting layer and the backplane insulation layer, easily causing structural failure such as breaking of the backplane.

Therefore, it is desired to provide an improved MEMS microphone to resolve the foregoing problem.

To illustrate the technical schemes in the embodiments of the present disclosure, the following briefly describes the accompanying drawings required for describing the embodiments. Apparently, the accompanying drawings in the following description merely show some embodiments of the present disclosure, and a person of ordinary skill in the art can derive other drawings from these accompanying drawings without creative efforts.

FIG. 1 is a schematic structural diagram of an MEMS microphone according to the present disclosure;

FIG. 2 is an exploded view of an MEMS microphone according to the present disclosure;

FIG. 3 is a cross-sectional view of FIG. 1 along a line A-A; and

FIG. 4 is a schematic structural diagram of a backplane of an MEMS microphone according to the present disclosure.

The technical schemes of embodiments of the present disclosure are described clearly and completely in the following with reference to the accompanying drawings in the embodiments of the present disclosure. Apparently, the described embodiments are merely some embodiments of the present disclosure, rather than all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present disclosure without creative efforts shall fall within the protection scope of the present disclosure.

FIG. 1 to FIG. 2 shows an MEMS microphone 100 according to the present disclosure. The MEMS microphone 100 includes a substrate 10 having a back cavity 11 and a capacitor system 60 fixedly disposed on the substrate 10 . The capacitor system 60 includes a backplane 50 and a vibrating diaphragm 20 that are spaced apart from each other. The backplane 50 is fixed to the substrate 10 . The vibrating diaphragm 20 is located on a side of the backplane 50 close to the substrate 10 , and in other implementations, may alternatively be located on a side of the backplane away from the substrate.

The backplane 50 includes a backplane insulation layer 40 and a backplane conducting layer 30 disposed on the backplane insulation layer 40 . The backplane conducting layer 30 may be embedded in and fixed to a side of the backplane insulation layer 40 close to the substrate 10 , or may be embedded in and fixed to a side of the backplane insulation layer away from the substrate. The backplane conducting layer 30 is smaller than the backplane insulation layer 40 . The backplane conducting layer is fixed to the substrate 10 by the backplane insulation layer 40 .

Referring to FIG. 3 and FIG. 4 , the backplane insulation layer 40 is provided with a first through hole 41 . The first through hole 41 includes a first sound hole 411 . The backplane conducting layer 30 includes a notch 31 provided on an outer edge. The first sound hole 411 is located in a location corresponding to the notch 31 and is in communication with the notch 31 . That is, the first sound hole 411 and the notch 31 are provided at a boundary between the backplane insulation layer 40 and the backplane conducting layer 30 . Therefore, a peripheral outline of the backplane conducting layer 30 passes through the first sound hole 411 of the backplane insulation layer, thereby reducing stress concentration of the backplane 50 and reducing a risk of structural failure such as breaking of the backplane 50 . A plurality of notches 31 are provided, and a plurality of first sound holes 411 are correspondingly provided.

In addition, the first through hole 41 of the backplane insulation layer 40 further includes a second sound hole 412 and a third sound hole 413 . The backplane conducting layer 30 is provided with a second through hole 32 . The second sound hole 412 corresponds to and is in communication with the second through hole 32 . The second sound hole 412 and the second through hole 32 are configured to intake a sound, so that an external sound arrives at a vibrating diaphragm after sequentially passing through the second sound hole and the second through hole. The third sound hole 413 is located on an outer side of the backplane conducting layer 30 , and may be used as a sound hole or may be used as a vent hole.

The foregoing descriptions are merely implementations of the present disclosure. It should be noted that a person of ordinary skill in the art can make improvements without departing from the inventive concept of the present disclosure, and all the improvements shall fall within the protection range of the present disclosure.