CN211570110U

CN211570110U - MEMS chip and MEMS sensor

Info

Publication number: CN211570110U
Application number: CN202021593918.9U
Authority: CN
Inventors: 詹竣凯; 何宪龙; 罗松成; 李承勲
Original assignee: Gettop Acoustic Co Ltd
Current assignee: Gettop Acoustic Co Ltd
Priority date: 2020-08-04
Filing date: 2020-08-04
Publication date: 2020-09-25
Anticipated expiration: 2030-08-04

Abstract

The utility model provides a MEMS chip and MEMS sensor. The chip comprises a substrate, a diaphragm and a back plate, wherein the diaphragm and the back plate are installed on the substrate, the back plate and the diaphragm are opposite at intervals and jointly form a capacitor structure, the back plate comprises a first area and a second area surrounding the periphery of the first area, the first area is provided with a first through hole, the second area is provided with a second through hole, and the aperture ratio of the first through hole of the first area is smaller than that of the second through hole of the second area. The utility model discloses a MEMS chip, the percent opening that sees through to reduce backplate central zone region increases the air damping between diaphragm and backplate, borrows this displacement volume that reduces per unit pressure in order to enlarge the radio reception scope to see through the diameter that reduces backplate central zone region's through-hole or increase the distance between the through-hole and all can make the sensing area who is formed with the electric capacity between diaphragm and backplate increase, and then make the subassembly can obtain better electric capacity signal output in the same sensing displacement volume.

Description

MEMS chip and MEMS sensor

Technical Field

The utility model relates to an electroacoustic technology field, in particular to MEMS chip and MEMS sensor.

Background

MEMS (Micro Electro mechanical System) sensors have been widely used in various portable mobile devices, and the component structure thereof needs to etch a large diameter through hole on a bottom substrate as a back cavity structure, and the relative position of the back cavity and a sensing film directly affects the stress variation of the structure boundary and the acquisition of low frequency signals.

As a typical MEMS sensor, a MEMS microphone is applied in a voice device, and its components are usually sensed in a large sound pressure environment, so that linear output of AOP (Acoustic Overload Point) large sound pressure sensing is increasingly important.

In the process of large sound pressure operation, in order to avoid overloading of sound pressure, the capacitance sensing structure of the MEMS microphone needs to reduce the displacement per unit pressure by increasing the rigidity of the sensing structure to expand the sound receiving range, but this also greatly reduces the sensitivity of the MEMS microphone.

At present, a double-diaphragm structure or a double-backplate structure is usually adopted, and the purpose of increasing the sensitivity is achieved by combining the reverse capacitance output characteristic of a double-layer sensing capacitor with a differential circuit, but the derived defect is that the cost of the component is greatly increased due to the complex structure.

SUMMERY OF THE UTILITY MODEL

In view of the above, the present invention is directed to a MEMS chip and a MEMS sensor that can effectively solve the above problems.

The back plate and the diaphragm are arranged on the substrate at intervals and opposite to each other so that a capacitor is formed between the back plate and the diaphragm, the back plate comprises a first area and a second area surrounding the periphery of the first area, the first area is provided with a first through hole, the second area is provided with a second through hole, and the opening rate of the first through hole of the first area is smaller than that of the second through hole of the second area.

In some embodiments, the spacing between the first through holes of the first area is greater than the spacing between the second through holes of the second area.

In some embodiments, the aperture of the first through hole of the first region is equal to the aperture of the second through hole of the second region.

In some embodiments, the first through hole of the first region has an aperture smaller than an aperture of the second through hole of the second region.

In some embodiments, the spacing distance between the first through holes of the first area is 2-3 times of the spacing distance between the second through holes of the second area.

In some embodiments, the aperture of the first via of the first region is 1/5 to 1/3 of the aperture of the second via of the second region.

In some embodiments, the substrate is provided with a back cavity, and the centerline of the first region is collinear with the centerline of the back cavity.

In some embodiments, the first via of the first region has an opening ratio of 1/5 to 1/3 of an opening ratio of the second via of the second region.

In some embodiments, the area of the second region is 3 to 5 times the area of the first region.

In another aspect, the present application also provides a MEMS sensor including the MEMS chip as described above.

The MEMS chip can maintain the original structure of the MEMS microphone when being applied to an MEMS sensor such as the MEMS microphone, only the through hole structure of the central area of the back plate needs to be subjected to the aperture ratio optimization design, the air damping between the diaphragm and the back plate is increased by reducing the aperture ratio of the central area of the back plate, thereby reducing the displacement of each unit pressure to enlarge the radio reception range, and the sensing area of the capacitor formed between the diaphragm and the back plate can be increased by reducing the diameter of the first through hole of the central area of the back plate or increasing the distance between the first through holes, so that the component can obtain better capacitance signal output in the same sensing displacement.

Drawings

Fig. 1 is a schematic side view of a MEMS chip according to an embodiment of the present invention.

Fig. 2 is a schematic side view of a MEMS chip according to another embodiment of the present invention.

Detailed Description

Before the embodiments are described in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The utility model discloses can be the embodiment that other modes realized. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," "having," and the like, herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. In particular, when "a certain component" is described, the present invention is not limited to the number of the component being one, and may include a plurality of components.

Referring to fig. 1, a MEMS chip includes a substrate 10, a diaphragm 30 mounted on the substrate 10, and a back plate 50, wherein the back plate 50 and the diaphragm 30 are spaced and opposed to each other and form a capacitor structure. The shape of the diaphragm 30 and the back plate 50 may be circular, square, hexagonal, etc.

The back plate 50 includes a first region 52 located at a central position and a second region 54 surrounding the first region 52, the first region 52 is provided with a first through hole 522, the second region 54 is provided with a second through hole 542, and external sound pressure enters a gap between the back plate 50 and the diaphragm 30 through the first through hole 522 and the second through hole 542 and causes the diaphragm 30 to move relative to the back plate 50, so that capacitance changes and corresponding electrical signals are output.

The opening ratio of the first through holes 522 of the first area 52 is smaller than the opening ratio of the second through holes 542 of the second area 54. The open porosity referred to herein refers to a ratio of a sum of cross-sectional areas of the first through-hole 522 (or the second through-hole 542) to an area of the first region 52 (or the second region 54).

In some embodiments, the first vias 522 of the first region 52 have an opening ratio that is 1/5 through 1/3 of the opening ratio of the second vias 542 of the second region 54.

In some embodiments, the spacing between the first through holes 522 of the first area 52 is greater than the spacing between the second through holes 542 of the second area 54. In some embodiments, the spacing between the first through holes 522 of the first area 52 is 2-3 times the spacing between the second through holes 542 of the second area 54. The spacing between vias as referred to herein refers to the shortest distance between the boundaries of adjacent vias.

In some embodiments, the aperture of the first through-hole 522 of the first area 52 is equal to the aperture of the second through-hole 542 of the second area 54.

Referring to fig. 2, in some embodiments, the interval between the first through holes 522 of the first area 52 is greater than the interval between the second through holes 542 of the second area 54, and the aperture of the first through holes 522 of the first area 52 is smaller than the aperture of the second through holes 542 of the second area 54.

In some embodiments, the aperture of the first through-hole 522 of the first region 52 is 1/5 through 1/3 of the aperture of the second through-hole 542 of the second region 54.

In some embodiments, the substrate 10 is provided with a back cavity 12, and the centerline of the first region 52 is collinear with the centerline of the back cavity 12.

In some embodiments, the area of the second region 54 is 3 to 5 times the area of the first region 52.

The MEMS chip of the present application can be used in a MEMS sensor such as a MEMS microphone, and when applied to a MEMS microphone, the original structure of the MEMS microphone can be maintained, and the aperture ratio optimization design is performed only for the acoustic aperture structure of the first region of the backplate 50 (i.e., the region directly facing the center of the back cavity 12), and the air damping between the diaphragm 30 and the backplate 50 is increased by reducing the aperture ratio of the center region of the backplate 50, thereby reducing the displacement per unit pressure to expand the sound reception range, and the sensing area of the capacitor formed between the diaphragm and the backplate can be increased by reducing the diameter of the first through hole 522 of the center region of the backplate 50 or increasing the distance between the first through holes 522, so that the device can obtain better capacitance signal output in the same sensing displacement.

The concepts described herein may be embodied in other forms without departing from the spirit or characteristics thereof. The particular embodiments disclosed should be considered illustrative rather than limiting. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. Any changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

1. A MEMS chip comprises a substrate, a diaphragm and a back plate, wherein the diaphragm and the back plate are arranged on the substrate, the back plate and the diaphragm are opposite at intervals and jointly form a capacitor structure, the back plate comprises a first area and a second area surrounding the periphery of the first area, and the MEMS chip is characterized in that: the first area is provided with a first through hole, the second area is provided with a second through hole, and the opening rate of the first through hole of the first area is smaller than that of the second through hole of the second area.

2. The MEMS chip of claim 1, wherein a spacing between the first vias of the first area is greater than a spacing between the second vias of the second area.

3. The MEMS chip of claim 2, wherein an aperture of the first via of the first region is equal to an aperture of the second via of the second region.

4. The MEMS chip of claim 1 or 2, wherein an aperture of the first via of the first region is smaller than an aperture of the second via of the second region.

5. The MEMS chip of claim 2 or 3, wherein a spacing distance between the first through holes of the first area is 2-3 times a spacing distance between the second through holes of the second area.

6. The MEMS chip of claim 4, wherein an aperture of the first via of the first region is 1/5 to 1/3 of an aperture of the second via of the second region.

7. The MEMS chip of claim 1 wherein the substrate is provided with a back cavity, and a centerline of the first region is collinear with a centerline of the back cavity.

8. The MEMS chip of claim 1, wherein an opening ratio of the first via of the first region is 1/5 through 1/3 of an opening ratio of the second via of the second region.

9. The MEMS chip of claim 1, wherein the second region has an area 3 to 5 times an area of the first region.

10. A MEMS sensor, characterized in that it comprises a MEMS chip according to any one of claims 1 to 9.