Patent Grant
12284473
The present disclosure relates to a field of sound-electric conversion technology, in particular to a micro-electro-mechanical system (MEMS) microphone.
With rapid development of the mobile communication technology in recent years, mobile communication devices such as portable phones, portable phones capable of accessing Internet, personal digital assistants and other devices that perform communication specially utilizing communication networks are used more and more. A microphone, especially a MEMS microphone, is one of the most important units used in the above-described devices.
A micro-electro-mechanical system (MEMS) microphone is an electroacoustic transducer produced by micro-mechanical technology, with small volume, excellent frequency response characteristic, low noise and the like. As electronic devices are getting miniaturized, lightened and thinned, MEMS microphones are increasingly widely used in those devices.
The MEMS microphone in the related art includes a substrate with a back cavity and a capacitor system arranged on the substrate, the capacitor system includes a back plate and a diaphragm arranged opposite to the back plate. In the manufacturing process of MEMS microphone, if the oxide between the diaphragm and the back plate is not cleaned, the reliability of the back plate will be affected. Usually, a release hole is added around the outer ring of the back plate hole of the back plate, and the oxide etchant enters from the release hole to clean the oxide between the diaphragm and the back plate, but this will make the MEMS microphone more venting channels, for the MEMS microphone with sound input from the top, the signal-to-noise ratio is reduced; for the MEMS microphone with sound input from the bottom, the low attenuation is affected.
Thus, it is necessary to provide a MEMS microphone to solve the problem.
In the view of the above, an objective of the present disclosure is to provide a MEMS microphone with a high reliability of the back plate.
In order to achieve the objective mentioned above, the present disclosure discloses a MEMS microphone, including: a substrate including a back cavity; a capacitive system arranged on the substrate, the capacitive system including a back plate and a diaphragm opposite to the back plate; wherein the diaphragm includes a vibration portion and a fixing portion surrounding the vibration portion and fixed to the substrate, the vibration portion and the fixing portion are spaced apart from each other by a slit, the fixing portion includes a plurality of releasing portions, and the releasing portions pass through the fixing portion.
Further, a plurality of through holes forms the releasing portions, and the plurality of through holes is evenly distributed in the fixing portion.
Further, a cross section of each through hole perpendicular to a vibration direction of the diaphragm is circular.
Further, a cross section of each through hole perpendicular to a vibration direction of the diaphragm is elliptical.
Further, each through hole extends toward a center of the diaphragm.
Further, each through hole includes a plurality of through portions which communicates with each other in sequence, each through portion includes a first through portion, a second through portion, a third through portion, a fourth through portion that communicates with the first through portion and the second through portion, and a fifth through portion that communicates with the second through portion and the third through portion, the fourth through portion and the fifth through portion are respectively located on both sides of the second through portion.
Further, the first through portion, the second through portion and the third through portion are parallel to each other.
Further, the fourth through portion and the fifth through portion are perpendicular to the second through portion.
Further, the diaphragm is in a shape of a racetrack, corners of the fixing portion are provided with a plurality of circular holes, and the through portions are located on a long axis side and a short axis side of the diaphragm.
Further, the diaphragm is located on a side of the back plate close to the substrate.
Many aspects of the exemplary embodiment can be better understood with reference to the following drawings. The components in the drawing are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure.
The present disclosure will hereinafter be described in detail with reference to exemplary embodiments. To make the technical problems to be solved, and technical solutions and beneficial effects of the present disclosure more apparent, the present disclosure is described in further detail together with the figure and the embodiment. It should be understood the specific embodiment described hereby is only to explain the disclosure, not intended to limit the disclosure.
Referring to
The diaphragm 12 is in a shape of a racetrack, and includes a vibrating portion 121, and a fixing portion 122 surrounding the vibrating portion 121 and fixed to the substrate 10. The vibration portion 121 and the fixing portion 122 are spaced apart from each other by a slit 120, the slit 120 has a continuous annular structure. The slit 120 is used to adjust the low attenuation value of the MEMS microphone 100, thereby adjusting the performance of the MEMS microphone 100. A support member 14 is located between the vibration portion 121 and the back plate 13, and the vibration portion 121 is fixedly connected to the back plate 13 through the support member 14.
The fixing portion 122 is provides with a plurality of releasing portions 1220, and each releasing portion 1220 penetrates through the fixing portion 122. During the manufacturing process of the MEMS microphone 100, an oxide etching solution can enter the diaphragm 12 through the releasing portion 1220, so as to remove the oxide between the diaphragm 12 and the back plate 13 and to improve the reliability of the back plate 13.
A plurality of through holes forms the releasing portions 1220, and the plurality of through holes 1220 is evenly distributed in the fixing portion 122. In this embodiment, the cross section of the through hole 1220 perpendicular to the vibration direction of the diaphragm 12 is circular, that is, the through hole 122 is a circular hole.
In addition, the back plate 13 is further provided with a blocking portion 15 on the side close to the diaphragm 12, the edge of the back plate 13 is fixed to the substrate 10 by connecting with the inner side of the connecting portion 101, and the diaphragm 12 is fixed to the substrate 10 by an insulating layer 3.
Referring to
Referring to
It can be seen that compared with the related art, since the diaphragm is provided with several releasing portion, the oxide etchant can enter the diaphragm through the releasing portion, so as to remove the oxide between the diaphragm and the back plate, and to improve the reliability of the back plate.
It is to be understood, however, that even though numerous characteristics and advantages of the present exemplary embodiment have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms where the appended claims are expressed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202221705318.6 | Jul 2022 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2022/114905 | 8/25/2022 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2024/000773 | 1/4/2024 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20100084721 | Wu | Apr 2010 | A1 |
| 20230217191 | Tong | Jul 2023 | A1 |
