CN220528234U

CN220528234U - Vibrating diaphragm, MEMS microphone and MEMS sensor

Info

Publication number: CN220528234U
Application number: CN202321877289.6U
Authority: CN
Inventors: 徐琦; 王飞飞; 王晓霞; 晋海涛; 张向超; 李建飞
Original assignee: Silex Microsystems Technology Beijing Co ltd
Current assignee: Silex Microsystems Technology Beijing Co ltd
Priority date: 2023-07-17
Filing date: 2023-07-17
Publication date: 2024-02-23
Anticipated expiration: 2033-07-17

Abstract

The utility model discloses a vibrating diaphragm, an MEMS microphone and an MEMS sensor, and belongs to the technical field of MEMS. The vibrating diaphragm comprises a vibrating diaphragm body, wherein the vibrating diaphragm body is disc-shaped, and a plurality of stress adjusting grooves which are arranged around the center of the vibrating diaphragm body along the circumferential direction of the vibrating diaphragm body are formed in the vibrating diaphragm body. The stress adjusting groove is arranged, so that the thickness of the vibrating diaphragm body can be changed. The thickness of the part of the vibrating diaphragm body provided with the stress adjusting groove is thinner, so that the distribution of the stress in the vibrating diaphragm body can be adjusted. And a plurality of stress adjustment grooves are arranged around the center of the vibrating diaphragm body along the circumference of the vibrating diaphragm body, so that the stress distribution of the film on the vibrating diaphragm can be further adjusted, and the warping degree of the vibrating diaphragm can be controlled and reduced. Compared with the conventional scheme of adjusting the technological parameters of the vibrating diaphragm through a test, the method shortens the time for solving the problem, accelerates the iteration of products and is beneficial to quickly realizing mass production.

Description

Vibrating diaphragm, MEMS microphone and MEMS sensor

Technical Field

The utility model relates to the technical field of MEMS (micro electro mechanical systems), in particular to a vibrating diaphragm, an MEMS microphone and an MEMS sensor.

Background

The diaphragm is a controlled vibration film widely used in MEMS (micro-electro-mechanical system, micro-electromechanical system) microphones and MEMS capacitive sensor products to sense external mechanical vibrations and convert them into electrical signals, and thus the diaphragm determines MEMS microphone and other types of MEMS capacitive sensor performance.

The vibrating diaphragm is generally divided into three types, namely a fixed supporting vibrating diaphragm, a semi-fixed supporting vibrating diaphragm and a free vibrating diaphragm according to the fixing mode of the vibrating diaphragm in the MEMS device structure. Whatever the fixing mode of the diaphragm is adopted, the warping degree of the diaphragm is required to meet the requirement. In the manufacturing process of the diaphragm, the stress of the diaphragm is controlled in a mode of debugging process parameters, so that the warping degree of the diaphragm is reduced, and the warping degree of the diaphragm meets the set requirement. For example, the diaphragms with different proportions of components (elements such as silicon, oxygen, phosphorus or boron) are manufactured, different diaphragm annealing conditions are set, and the like. However, the area of the fixed supporting point of the free vibrating diaphragm is smaller, the warping degree of the free vibrating diaphragm is more difficult to control, and verification proves that even if a mode of debugging technological parameters is adopted, the stable warping degree control effect of the free vibrating diaphragm is difficult to obtain, and the difficulty of mass production is high.

Disclosure of Invention

In view of the above problems, the present utility model provides a diaphragm, a MEMS microphone and a MEMS sensor, which can solve the problem that the diaphragm is easy to warp in the conventional MEMS microphone and MEMS sensor.

In a first aspect, a diaphragm is provided, the diaphragm includes a diaphragm body, the diaphragm body is discoid, a plurality of stress adjustment grooves are arranged along the circumference of the diaphragm body around the center of the diaphragm body on the diaphragm body.

Optionally, the orthographic projection of the stress adjustment groove on the vibrating diaphragm body is arc-shaped.

Optionally, when the diaphragm is a free diaphragm, the widths of the stress adjustment grooves increase in a gradient from the supporting point of the free diaphragm to a direction away from the supporting point.

Optionally, when the diaphragm is a fixed support diaphragm or a semi-fixed support diaphragm, the width of the stress adjustment grooves is increased in a gradient manner from the center point of the diaphragm body to a radial direction away from the center point.

Optionally, the width of the stress adjustment groove is 0.3 um-10 um.

Optionally, the depth of the stress adjusting groove is 0.1-0.7 times of the thickness of the vibrating diaphragm body.

Optionally, the diaphragm body has an upper surface and a lower surface opposite to each other, and the stress adjustment grooves are located on at least one of the upper surface and the lower surface.

Optionally, the orthographic projection of the stress adjustment groove on the diaphragm body is a straight line, a rectangle, a circle, an ellipse or a polygon.

In a second aspect, there is provided a MEMS microphone comprising a diaphragm as described in the first aspect.

In a third aspect, there is provided a MEMS sensor comprising a diaphragm as described in the first aspect.

The technical scheme provided by the embodiment of the utility model has at least the following technical effects or advantages:

according to the vibrating diaphragm, the MEMS microphone and the MEMS sensor provided by the embodiment of the utility model, the thickness of the vibrating diaphragm body can be changed by arranging the plurality of stress adjusting grooves on the disc-shaped vibrating diaphragm body. The part provided with the stress adjusting groove is thinner in the thickness of the vibrating diaphragm body, so that the distribution of the stress in the vibrating diaphragm body can be adjusted. And a plurality of stress adjustment grooves are arranged around the center of the vibrating diaphragm body along the circumference of the vibrating diaphragm body, so that the stress distribution of the film on the vibrating diaphragm can be further adjusted, and the warping degree of the vibrating diaphragm can be controlled and reduced.

The foregoing description is only an overview of the present utility model, and is intended to be implemented in accordance with the teachings of the present utility model in order that the same may be more clearly understood and to make the same and other objects, features and advantages of the present utility model more readily apparent.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the utility model. Also, like reference numerals are used to designate like parts throughout the figures. In the drawings:

fig. 1 is a schematic structural diagram of a diaphragm according to an embodiment of the present utility model;

FIG. 2 is a schematic illustration of a free diaphragm of conventional construction;

FIG. 3 is a schematic cross-sectional view of a free diaphragm according to an embodiment of the present utility model;

FIG. 4 is a schematic cross-sectional view of another free diaphragm according to an embodiment of the present utility model;

fig. 5 is a schematic structural diagram of a MEMS capacitive sensor according to an embodiment of the present utility model.

Detailed Description

Exemplary embodiments of the present utility model will be described in more detail below with reference to the accompanying drawings.

Various structural schematic diagrams according to embodiments of the present utility model are shown in the accompanying drawings. The figures are not drawn to scale, wherein certain details are exaggerated for clarity of presentation and may have been omitted. The shapes of the various regions, layers and relative sizes, positional relationships between them shown in the drawings are merely exemplary, may in practice deviate due to manufacturing tolerances or technical limitations, and one skilled in the art may additionally design regions/layers having different shapes, sizes, relative positions as actually required.

In the context of the present utility model, when a layer/element is referred to as being "on" another layer/element, it can be directly on the other layer/element or intervening layers/elements may be present therebetween. In addition, if one layer/element is located "on" another layer/element in one orientation, that layer/element may be located "under" the other layer/element when the orientation is turned. In the context of the present utility model, similar or identical components may be indicated by identical or similar reference numerals.

In order to better understand the above technical solutions, the following detailed description will be made with reference to specific embodiments, and it should be understood that specific features in the embodiments and examples of the present disclosure are detailed descriptions of the technical solutions of the present disclosure, and not limiting the technical solutions of the present disclosure, and the technical features in the embodiments and examples of the present disclosure may be combined with each other without conflict.

Fig. 1 is a schematic structural diagram of a diaphragm according to an embodiment of the present utility model, as shown in fig. 1, the diaphragm 100 includes a diaphragm body 101, and the diaphragm body 101 is disc-shaped. The diaphragm body 101 has thereon a plurality of stress adjustment grooves 102 arranged around the center of the diaphragm body 101 in the circumferential direction of the diaphragm body 101.

In this embodiment, the plurality of stress adjustment grooves 102 may be set to a set shape in a simulation manner, and the distribution densities of the plurality of stress adjustment grooves 102 are designed and matched according to the local different warping degrees of the vibrating diaphragm, so as to play a better role in adjusting stress, avoid the complicated steps of repeatedly debugging the manufacturing process parameters of the vibrating diaphragm, and obtain the vibrating diaphragm with the warping degree meeting the requirements only by changing the shape and the distribution of the stress adjustment grooves, thereby having stronger flexibility.

The distribution density of the stress adjustment grooves 102 may be the area occupied by the stress adjustment grooves 102 on the surface of the diaphragm. For the position (the position with large warping degree) where the diaphragm is easy to warp locally, the stress adjusting groove 102 with larger area can be correspondingly arranged in the region, so that a better stress adjusting effect is achieved.

As shown in fig. 1, in an implementation manner of this embodiment, an orthographic projection of the stress adjustment groove 102 on the diaphragm body 101 is a circular arc. Simulation verification shows that when the orthographic projection is in the shape of a circular arc, the stress adjustment groove 102 has a better effect on adjusting the stress of the diaphragm. In other implementations of the present embodiment, the orthographic projection of the stress adjustment groove 102 on the diaphragm body 101 may be a straight line, a rectangle, a circle, an ellipse, or a polygon, which may also play a role in stress adjustment.

Illustratively, the center of each arc coincides with the center of the diaphragm body 101.

The vibrating diaphragm is generally divided into three types, namely a fixed supporting vibrating diaphragm, a semi-fixed supporting vibrating diaphragm and a free vibrating diaphragm according to the fixing mode of the vibrating diaphragm in the MEMS device structure. Wherein, fixed support vibrating diaphragm and semi-fixed support vibrating diaphragm all have a plurality of strong points, and free vibrating diaphragm only has a strong point and area of support is littleer.

Alternatively, as shown in fig. 1, when the diaphragm is a fixed support diaphragm or a semi-fixed support diaphragm, the width of the stress adjustment grooves 102 is increased in a gradient manner from the center point of the diaphragm body 101 to a radial direction away from the center point. Since the farther from the center point of the diaphragm body 101, the greater the degree of warpage of the diaphragm, the width is set to be increased in a gradient, and a better stress improvement effect can be achieved.

Optionally, when the diaphragm is a fixed support diaphragm or a semi-fixed support diaphragm, and the orthographic projection of the stress adjustment groove 102 on the diaphragm body 101 is circular arc, the arc length of each section of circular arc is gradually increased in the radial direction from the center point of the diaphragm body 101 to the radial direction away from the center point, so as to achieve a better stress improvement effect.

Fig. 2 is a schematic structural view of a free diaphragm of a conventional structure, and as shown in fig. 2, the free diaphragm 200 includes a diaphragm body 201 and supporting points 202. When the free diaphragm 200 is not warped, the end of the diaphragm body 201 away from the supporting point 202 is at the position a in fig. 2; when the free diaphragm 200 is warped, the end of the diaphragm body 201 away from the supporting point 202 is at the position B in fig. 2.

Fig. 3 is a schematic cross-sectional structure of a free diaphragm according to an embodiment of the present utility model, and as shown in fig. 3, the free diaphragm 300 includes a diaphragm body 301, a plurality of stress adjustment grooves 302, and support points 303.

When the diaphragm is the free diaphragm 300, the width of the stress adjustment grooves 302 increases in a gradient from the support point 303 of the free diaphragm 300 to a direction away from the support point 303. Since the farther away from the supporting point 303, the greater the warping degree of the diaphragm, the greater the width of the stress adjustment grooves 302 is, the greater the area occupied by the stress adjustment grooves 302 on the surface of the diaphragm can be, so as to play a better role in adjusting stress.

Optionally, when the diaphragm is the free diaphragm 300 and the orthographic projection of the stress adjustment groove 302 on the diaphragm body 301 is a circular arc, the arc length of each circular arc is gradually increased from the supporting point 303 of the free diaphragm 300 to the direction away from the supporting point 303, so as to achieve a better stress improvement effect.

Optionally, the width of the stress adjustment groove is 0.3um to 10um. If the width of the stress adjustment groove is too narrow, a good stress adjustment effect cannot be achieved. If the width of the stress adjusting groove is too wide, the performance of the vibrating diaphragm is affected.

It should be noted that, in this embodiment, for different types of diaphragms (fixed support diaphragm, semi-fixed support diaphragm and free diaphragm), the width of the stress adjustment grooves may be changed in a gradient manner in the width range in the above manner, so as to achieve a better stress adjustment effect. The width of the plurality of stress accommodating grooves may be the same.

Optionally, the depth of the stress adjustment groove is 0.1-0.7 times of the thickness of the vibrating diaphragm body. Because the depth of each stress adjustment groove of the diaphragm has a relatively large influence on the performance of the MEMS device provided with the diaphragm, the processing error of the diaphragm needs to be controlled. The diaphragm corresponding to the stress adjusting groove cannot be cut through in general, and the diaphragm at the position where the stress adjusting groove is reserved needs to have a certain thickness. If the depth of the stress adjusting groove is too deep, the performance of the vibrating diaphragm is also affected; too shallow depth can not achieve better stress adjustment effect.

Optionally, the diaphragm body has opposite upper and lower surfaces, and the plurality of stress adjustment grooves are located on at least one of the upper and lower surfaces.

Taking the free diaphragm as an example, as shown in fig. 3, the stress adjustment grooves 302 of the free diaphragm 300 are all located on the upper surface of the diaphragm body 300. Fig. 4 is a schematic cross-sectional view of another free diaphragm according to an embodiment of the present utility model, as shown in fig. 4, in which a plurality of stress adjustment grooves 302 of the free diaphragm 300 are located on the lower surface of the diaphragm body 301. In other embodiments, the diaphragm body 301 has stress accommodating grooves 302 on both the upper and lower surfaces. On one hand, the warping degree of the vibrating diaphragm can be reduced, and on the other hand, the uniform equivalent capacitance can be obtained. For other types of diaphragms, multiple stress accommodating grooves 302 may also be provided on the upper and/or lower surfaces of each diaphragm body to meet different usage requirements.

In a specific implementation manner of this embodiment, the diameter of the diaphragm body 101 is about 900um, and the diaphragm body 101 is provided with a plurality of stress adjustment grooves 102 with circular arc shape orthographic projection on the diaphragm body 101. The distribution of the stress adjustment grooves 102 on the diaphragm body 101 is shown in fig. 1. The width of each stress adjustment groove 102 is 4.5um, the radial distance is 2.5um, the depth is 0.6um, and the thickness is 1/2 of the diaphragm body 101, i.e. half of the diaphragm thickness is reserved to be not etched, and the thickness is 1.2um. The stress adjustment grooves 102 may be etched on the upper surface of the diaphragm body 101 by an etching process.

The embodiment of the utility model also provides a MEMS microphone, which comprises the vibrating diaphragm in the embodiment. The specific structure of the diaphragm may be referred to the related description of the above embodiments, and will not be repeated here.

The embodiment of the utility model also provides a MEMS sensor, which comprises the vibrating diaphragm in the embodiment. Fig. 5 is a schematic structural diagram of a MEMS capacitive sensor according to an embodiment of the present utility model, as shown in fig. 5, where the MEMS capacitive sensor 500 includes a diaphragm 501, a back-electrode plate 502, and a substrate silicon wafer 503. The diaphragm 501 is located between the backplate 502 and the substrate silicon wafer 503. The equivalent capacitance formed between the diaphragm 501 and the backplate 502 is stable and device performance is therefore stable because the diaphragm 501 does not substantially warp due to the stress accommodating grooves in the diaphragm 501. Compared with the conventional scheme of adjusting the technological parameters of the vibrating diaphragm through a test, the method shortens the time for solving the problem, accelerates the iteration of products and is beneficial to quickly realizing mass production.

In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the utility model may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

Similarly, it should be appreciated that in the above description of exemplary embodiments of the utility model, various features of the utility model are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. However, the disclosed method should not be construed as reflecting the intention that: i.e., the claimed utility model requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this utility model.

It should be noted that the above-mentioned embodiments illustrate rather than limit the utility model, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The use of the words first, second, third, etc. do not denote any order. These words may be interpreted as names.

Claims

1. The vibrating diaphragm is characterized by comprising a vibrating diaphragm body, wherein the vibrating diaphragm body is disc-shaped, and a plurality of stress adjusting grooves are formed in the vibrating diaphragm body and are arranged around the center of the vibrating diaphragm body along the circumferential direction of the vibrating diaphragm body;

when the vibrating diaphragm is a free vibrating diaphragm, the width of the stress regulating grooves is increased in a gradient manner from the supporting point of the free vibrating diaphragm to the direction away from the supporting point.

2. The diaphragm of claim 1, wherein the orthographic projection of the stress adjustment groove on the diaphragm body is circular arc.

3. The diaphragm of claim 1, wherein when the diaphragm is a fixed support diaphragm or a semi-fixed support diaphragm, the plurality of stress adjustment grooves have a width that increases in a gradient from a center point of the diaphragm body to a radial direction away from the center point.

4. A diaphragm according to claim 1 or 3, wherein the stress accommodating groove has a width of 0.3um to 10um.

5. The diaphragm of claim 1, wherein the stress adjustment groove has a depth of 0.1 to 0.7 times the thickness of the diaphragm body.

6. The diaphragm of claim 1 wherein the diaphragm body has opposed upper and lower surfaces, the plurality of stress accommodating grooves being located on at least one of the upper and lower surfaces.

7. The diaphragm of claim 1, wherein the orthographic projection of the stress adjustment groove on the diaphragm body is a straight line, a rectangle, a circle, an ellipse, or a polygon.

8. A MEMS microphone comprising a diaphragm according to any one of claims 1 to 7.

9. A MEMS sensor comprising a diaphragm according to any one of claims 1 to 7.