CN215072978U

CN215072978U - Microphone chip, MEMS microphone and electronic equipment

Info

Publication number: CN215072978U
Application number: CN202121614808.0U
Authority: CN
Inventors: 孙恺; 荣根兰; 孟燕子; 胡维
Original assignee: Memsensing Microsystems Suzhou China Co Ltd
Current assignee: Memsensing Microsystems Suzhou China Co Ltd
Priority date: 2021-07-15
Filing date: 2021-07-15
Publication date: 2021-12-07
Anticipated expiration: 2031-07-15

Abstract

The utility model provides a pair of microphone chip, MEMS microphone and electronic equipment, the microphone chip includes: the substrate, the second insulating layer, the vibrating diaphragm structure, the first insulating layer and the first back plate are sequentially stacked from bottom to top; the vibrating diaphragm structure comprises a first vibrating diaphragm and a second vibrating diaphragm which are independently arranged, the second vibrating diaphragm is arranged on the periphery of the first vibrating diaphragm, and an isolation groove is formed between the first vibrating diaphragm and the second vibrating diaphragm; the first insulating layer is of a first annular structure, the second insulating layer is of a second annular structure, and on the vertical projection plane, the inner contour of the first annular structure and/or the inner contour of the second annular structure do not exceed the projection of the first diaphragm. The embodiment of the application provides a microphone chip, an MEMS microphone and electronic equipment which are high in sensitivity, regular in structure, easy to process and beneficial to packaging.

Description

Microphone chip, MEMS microphone and electronic equipment

Technical Field

The utility model relates to a microphone chip, MEMS microphone and electronic equipment.

Background

Existing MEMS (Micro-Electro-Mechanical systems) microphones typically include a substrate, a back electrode, and a diaphragm. The diaphragm is movably disposed between the substrate and the back electrode. And a capacitor is formed between the diaphragm and the back electrode. A back cavity is disposed on the substrate. When the sound wave is transmitted towards the back cavity, the sound wave will cause the vibration of the diaphragm, thereby converting the sound wave signal into an electrical signal.

Existing diaphragms generally include two types. The outer contour of the first diaphragm is almost equal in size to the outer contour of the substrate. The part of the diaphragm, which is positioned outside the back cavity, is a solid area. The solid areas are all parasitic capacitances. The parasitic capacitance voltage division reduces the ultimate sensitivity of the MEMS microphone. The outer contour dimension of the second diaphragm is almost equal to the inner contour dimension of the back cavity. Although parasitic capacitance can be removed by the second diaphragm, steps around the MEMS microphone are increased, so that the whole layer of the MEMS microphone is uneven, and the steps are enlarged and are not beneficial to subsequent packaging.

It should be noted that the above background description is only for the sake of clarity and complete description of the technical solutions of the present invention, and is set forth for facilitating understanding of those skilled in the art. These solutions are not considered to be known to the person skilled in the art merely because they have been set forth in the background section of the present invention.

SUMMERY OF THE UTILITY MODEL

In view of this, the technical problem to be solved by the present invention is to provide a microphone chip, a MEMS microphone and an electronic device, which have high sensitivity, regular structure, easy processing and are favorable for packaging.

A microphone chip comprising: the substrate, the second insulating layer, the vibrating diaphragm structure, the first insulating layer and the first back plate are sequentially stacked from bottom to top; the vibrating diaphragm structure comprises a first vibrating diaphragm and a second vibrating diaphragm which are independently arranged; the second diaphragm is arranged on the outer periphery of the first diaphragm; an isolation groove is formed between the first diaphragm and the second diaphragm; the first insulating layer is of a first annular structure, the second insulating layer is of a second annular structure, and on a vertical projection plane, the inner contour of the first annular structure and/or the inner contour of the second annular structure do not exceed the projection of the first diaphragm.

As a preferred embodiment, a third diaphragm is further disposed above the first back plate to form a dual-diaphragm microphone chip.

As a preferred embodiment, the first back plate comprises a two or more layer structure, wherein one layer is a conductive layer.

In a preferred embodiment, on the vertical projection plane, an outer contour of the conductive layer does not exceed an inner contour of the second diaphragm.

As a preferred embodiment, the substrate has a first surface and a second surface that are arranged opposite to each other, and the substrate is provided with a back cavity that penetrates through the first surface and the second surface, the back cavity facing the first diaphragm.

As a preferred embodiment, the outer contour size of the second diaphragm is not smaller than the outer contour size of the substrate; on the vertical projection plane, the projection of the back cavity is located in the projection of the first diaphragm.

In a preferred embodiment, a side of the first insulating layer facing the diaphragm structure is embedded in the isolation groove.

As a preferred embodiment, a plurality of sound holes are arranged on the first back plate; the projection of the sound holes on the outermost side on the vertical projection plane does not exceed the inner contour of the first annular structure.

In a preferred embodiment, on the vertical projection plane, the inner contour of the second diaphragm does not exceed the outer contour of the second annular structure.

In a preferred embodiment, the width of the isolation trench is less than 5 μm.

In a preferred embodiment, the width of the isolation trench is greater than 0.1 μm.

In a preferred embodiment, a pressure relief hole is disposed on the first diaphragm.

A microphone chip comprising: the substrate, the second insulating layer, the first back plate, the first insulating layer and the vibrating diaphragm structure are sequentially stacked from bottom to top; the vibrating diaphragm structure comprises a first vibrating diaphragm and a second vibrating diaphragm which are independently arranged; the second diaphragm is arranged on the outer periphery of the first diaphragm; an isolation groove is formed between the first diaphragm and the second diaphragm; the first insulating layer is of a first annular structure, and on a vertical projection plane, the inner contour of the first annular structure does not exceed the projection of the first diaphragm.

In a preferred embodiment, a second back plate is further disposed above the diaphragm structure to form a dual-back-plate microphone chip.

A MEMS microphone comprises the microphone chip.

An electronic device comprises the microphone.

The utility model discloses microphone chip, MEMS microphone and electronic equipment, through setting up the vibrating diaphragm structure, this vibrating diaphragm structure is including the first vibrating diaphragm and the second vibrating diaphragm of independent setting. The second diaphragm is disposed at an outer periphery of the first diaphragm. An isolation groove is formed between the first diaphragm and the second diaphragm. On one hand, the first vibrating diaphragm and the second vibrating diaphragm are electrically isolated through the isolation groove; on the other hand, the processing of a semiconductor process is facilitated, so that the first vibrating diaphragm and the peripheral parasitic area (namely the second vibrating diaphragm) are electrically disconnected, the parasitic capacitance is reduced to the maximum extent, and the sensitivity of the microphone chip is improved. Furthermore, the outer contour of the conducting layer is within the projection range of the inner contour of the second diaphragm, and the conducting layer has no overlapping part with the second diaphragm on the vertical projection plane, so that the parasitic capacitance is reduced as much as possible. Furthermore, because the second vibrating diaphragm is located outside the first vibrating diaphragm, the second vibrating diaphragm can avoid increasing steps around the first vibrating diaphragm, so that the microphone chip has a regular structure and is beneficial to subsequent packaging. Further, one side of the first insulating layer facing the diaphragm structure is embedded into the isolation groove; so because filled into first insulating layer in the isolation groove, so make between first vibrating diaphragm and the second vibrating diaphragm through first insulating layer reinforcing insulating nature, and then guarantee the electrical isolation effect. Therefore, the microphone chip, the MEMS microphone and the electronic device have the advantages of high sensitivity, regular structure, easiness in processing and convenience in packaging.

Furthermore, the inner contour of the first annular structure and/or the inner contour of the second annular structure do not exceed the projection of the first diaphragm, and the diaphragm is fixed, so that compared with the prior art, for example, the first diaphragm is fixed through a plurality of supporting points, the process flows of the first annular structure and the second annular structure are simpler and more convenient, the stress on the peripheral side of the first diaphragm is more uniform and can not be concentrated on each supporting point, so that the first diaphragm is not easy to break near the supporting points, and the reliability is higher.

Specific embodiments of the present invention are disclosed in detail with reference to the following description and accompanying drawings, which specify the manner in which the principles of the invention may be employed. It should be understood that the embodiments of the present invention are not so limited in scope. The embodiments of the invention include many variations, modifications and equivalents within the spirit and scope of the appended claims.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments, in combination with or instead of the features of the other embodiments.

It should be emphasized that the term "comprises/comprising" when used herein, is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps or components.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a first embodiment of a microphone chip according to an embodiment of the present invention.

Fig. 2 is a schematic structural diagram of a second embodiment of a microphone chip according to an embodiment of the present invention.

Fig. 3 is a schematic structural diagram of a diaphragm structure according to an embodiment of the present invention.

Description of reference numerals:

11. a substrate; 13. a back cavity; 15. a first diaphragm; 16. a second diaphragm; 18. an isolation trench; 19. a first back plate; 21. a first insulating layer; 23. a sound hole; 25. a second insulating layer; 26. a first central aperture; 27. a second central aperture; 29. a pressure relief vent; 31. a first layer; 33. a second layer; 35. a cavity; 37. a first surface; 39. a second surface; 41. a diaphragm structure.

Detailed Description

In order to make the technical solutions in the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts shall fall within the protection scope of the present invention.

It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a single embodiment.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In this specification, a component of an embodiment of the present invention is defined as "up" in a direction toward or facing a user and "down" in a direction away from the user in a normal use state.

Specifically, the upward direction illustrated in fig. 1 to 3 is defined as "up", and the downward direction illustrated in fig. 1 to 3 is defined as "down".

It should be noted that the definitions of the directions in the present specification are only for convenience of describing the technical solution of the present invention, and do not limit the directions of the microphone chip of the embodiments of the present invention in other scenarios, including but not limited to use, test, transportation, and manufacture, which may cause the orientation of the component to be reversed or the position of the component to be changed.

The embodiment of the utility model provides a microphone chip, its sensitivity is high, structural rule, easily processing and be favorable to the encapsulation. Specifically, fig. 1 is a schematic structural diagram of a first embodiment of a microphone chip according to an embodiment of the present invention. Fig. 2 is a schematic structural diagram of a second embodiment of a microphone chip according to an embodiment of the present invention. The structures of the first and second embodiments will be described below with reference to fig. 1 and 2, respectively.

As shown in fig. 1, in the present embodiment, the microphone chip includes a substrate 11, a second insulating layer 25, a diaphragm structure 41, a first insulating layer 21, and a first back plate 19, which are stacked in this order from bottom to top.

Further, in the present embodiment, the substrate 11 may be low-resistance silicon. The base 11 serves as a substrate to support the microphone chip structure. Further, a back cavity 13 is provided on the substrate 11. Specifically, the substrate 11 has a first surface 37 and a second surface 39 facing away from each other. The first surface 37 is located above the second surface 39. The back cavity 13 extends through the first surface 37 and the second surface 39. The back cavity 13 faces the first diaphragm 15. Further, the back cavity 13 is formed by etching on the substrate 11.

Further, as shown in fig. 1, a second insulating layer 25 is disposed between the substrate 11 and the diaphragm structure 41. The second insulating layer 25 is used to support the diaphragm structure 41 and the first backplate 19. Further, the second insulating layer 25 is a second ring structure. The second annular structure has a second central hole 27 for exposing the first diaphragm 15 towards the back cavity 13, thereby enabling acoustic wave energy to propagate towards the back cavity 13.

Further, as shown in fig. 1, the diaphragm structure 41 includes a first diaphragm 15 and a second diaphragm 16 which are independently provided. The second diaphragm 16 is provided at the outer periphery of the first diaphragm 15. And an isolation groove 18 is formed between the first diaphragm 15 and the second diaphragm 16. The isolation groove 18 is rounded, as shown in fig. 3, for example. Of course, the isolation groove 18 is not limited to a circle, but may have other shapes, such as a rectangle, and the application is not limited thereto. Further, as shown in fig. 3, for example, the first diaphragm 15 is circular. The second diaphragm 16 has an annular shape. The first diaphragm 15 is located within an annular second diaphragm 16. Further, the first diaphragm 15 and the second diaphragm 16 are independent of each other, and there is no mutual contact therebetween. In this way, the isolation groove 18 is provided to electrically isolate the first diaphragm 15 from the second diaphragm 16, so that the first diaphragm 15 is electrically disconnected from the peripheral parasitic region (i.e., the second diaphragm 16), thereby reducing the parasitic capacitance to the maximum extent and improving the sensitivity of the microphone. Further, in order to facilitate processing and enable electrical isolation between the first diaphragm 15 and the second diaphragm 16, the width of the isolation groove 18 is greater than 0.1 μm.

Further, on a vertical projection plane, the projection of the back cavity 13 is located within the projection of the first diaphragm 15. The substrate 11 can thus form a support for the first diaphragm 15, so that the first diaphragm 15 can be supported above the back cavity 13. And since the second diaphragm 16 is located outside the first diaphragm 15, on the one hand, the substrate 11 can also support the second diaphragm 16, so that the second diaphragm 16 can be supported above the substrate 11. On the other hand, the second diaphragm 16 can avoid increasing steps around the first diaphragm 15, so that the microphone has a regular structure and is beneficial to subsequent packaging. Further, the first diaphragm 15 and the second diaphragm 16 are both silicon diaphragms made of polysilicon.

Further, the outer contour size of the second diaphragm 16 is not smaller than the outer contour size of the substrate 11. Preferably, the outer contour dimension of the second diaphragm 16 is equal to the outer contour dimension of the substrate 11. Therefore, the second diaphragm 16 can occupy the space formed by the substrate 11 and the first diaphragm 15, so that the microphone has a more regular structure, and the increase of steps around the first diaphragm 15 is avoided, which is beneficial to subsequent packaging.

Further, as shown in fig. 1, the first insulating layer 21 is disposed between the first back plate 19 and the diaphragm structure 41. The first insulating layer 21 is used for isolating the first back plate 19 from the diaphragm structure 41. Further, the first insulating layer 21 is a first ring structure. Specifically, the first annular structure has a first central bore 26.

Further, as shown in fig. 1, the first back plate 19 is disposed on a side of the diaphragm structure 41 away from the first insulating layer 21. As shown in fig. 1, the first back plate 19 is located above the diaphragm structure 41. Further, the first back plate 19 and the diaphragm structure 41 form a capacitor. Specifically, the first diaphragm 15, the second diaphragm 16, and the first back plate 19 all have a conductive function. The first back plate 19 is disposed opposite to the diaphragm structure 41. Thus, the first back plate 19 and the diaphragm structure 41 form a capacitor plate. Further, a cavity 35 is formed between the first back plate 19 and the first diaphragm 15. Further, the first back plate 19 is provided with a plurality of sound holes 23. The number may be 1 or more. In the present embodiment, for example, as shown in fig. 1, the number of the sound holes 23 is 9. Of course, the number of the sound holes 23 is not limited to 9, and may be other numbers, which is not specified in the present application. The sound hole 23 is opposed to the first diaphragm 15. So that air can enter the cavity 35 through the sound holes 23. The air pressure generated by the sound causes the first diaphragm 15 to vibrate, thereby changing the capacitance, and thus realizing the acoustoelectric conversion. Further, the first back plate 19 includes a two-layer or more-layer structure. One of the first back plate 19 is a conductive layer. As shown for example in fig. 1, the first back plate 19 comprises a first layer 31 and a second layer 33. The first layer 31 is located above the second layer 33. The first layer 31 is a conductive layer.

Further, in the first embodiment, a third diaphragm is further disposed above the first back plate 19 to form a dual-diaphragm microphone chip.

Further, on the vertical projection plane, the outer contour of the conductive layer does not exceed the inner contour of the second diaphragm 16. The outer contour of the conductive layer is within the projection range of the inner contour of the second diaphragm 16, and the conductive layer does not overlap with the second diaphragm 16 on the vertical projection plane, so that the parasitic capacitance is reduced as much as possible.

Further, as shown in fig. 1, on the vertical projection plane, the inner contour of the first ring-shaped structure and/or the inner contour of the second ring-shaped structure does not exceed the projection of the first diaphragm 15, so as to fix the first diaphragm 15. As shown in fig. 1, for example, the inner diameter of the first center hole 26 is smaller than the outer diameter of the first diaphragm 15. On the one hand, the first central hole 26 can expose the first back plate 19 to the first diaphragm 15, so that a capacitor is formed between the first back plate 19 and the first diaphragm 15. The first insulating layer 21 can be used for isolating the first back plate 19 from the diaphragm structure 41, and can be used for supporting and fixing the first back plate 19; and on the other hand for fixing the first diaphragm 15. The relatively closed design of the first diaphragm 15 can better improve the low-frequency performance of the device. Further, the side of the first insulating layer 21 facing the diaphragm structure 41 is embedded in the isolation groove 18. Specifically, the material of the first insulating layer 21 is silicon oxide. During manufacturing, silicon oxide may be coated on the diaphragm structure 41 through a semiconductor manufacturing process, and a portion of the silicon oxide is filled in the isolation trench 18. Thus, since the first insulating layer 21 is filled in the isolation groove 18, the insulation between the first diaphragm 15 and the second diaphragm 16 is enhanced by the first insulating layer 21, and the electrical isolation effect is ensured. Further, in order to facilitate the filling of the first insulating layer 21 into the isolation groove 18, the width of the isolation groove 18 is less than 5 μm. In some embodiments, the width of isolation trench 18 may be 4.5 microns, 4 microns, 3.5 microns, 3 microns, 2.5 microns, 2 microns, 1.5 microns, 1 micron, 0.5 microns, or some value between any two adjacent of the foregoing, without limitation.

Further, as shown in fig. 1, on the vertical projection plane, the inner contour of the second annular structure does not exceed the projection of the first diaphragm 15. Specifically, the inner diameter of the second center hole 27 is not larger than the outer diameter of the first diaphragm 15. The second ring-shaped structure thus supports and fixes the first diaphragm 15. Further, the second annular structure is used to seal the first diaphragm 15. This second annular structure can thus also be used to achieve a sealing of the first diaphragm 15. The relatively closed design of the first diaphragm 15 can better improve the low-frequency performance of the device.

Further, on the vertical projection plane, the inner contour of the second diaphragm 16 is located within the outer contour of the first insulating layer 21. In this way, the first insulating layer 21 at least partially overlaps the second diaphragm 16 on the projection plane, thus reducing the parasitic capacitance.

Further, the projection of the outermost sound holes 23 on the perpendicular projection plane does not exceed the inner contour of the first annular structure. Thus the low frequency performance of the device is enhanced by the first annular structure as air enters the cavity 35 through the acoustic holes 23.

Further, the outer contour dimension of the first insulating layer 21 is not smaller than the outer contour dimension of the substrate 11. Preferably, the outer contour dimension of the first insulating layer 21 is equal to the outer contour dimension of the substrate 11. Therefore, the structure of the microphone is more regular, the steps around the first insulating layer 21 are prevented from being increased, and subsequent packaging is facilitated.

Further, on the vertical projection plane, the inner contour of the second diaphragm 16 does not exceed the outer contour of the second annular structure. On one hand, the structure of the microphone is more regular, steps around the second insulating layer 25 are prevented from being increased, and subsequent packaging is facilitated; the second insulating layer 25 on the other hand can support and fix the second diaphragm 16. Further, the material of the second insulating layer 25 is silicon oxide. Further, the outer diameter of the second insulating layer 25 is not smaller than the outer contour dimension of the substrate 11. Preferably, the outer contour dimension of the second insulating layer 25 is equal to the outer contour dimension of the substrate 11. Therefore, the microphone has a more regular structure, and the increase of steps around the substrate 11 is avoided, thereby being beneficial to subsequent packaging.

Further, the first diaphragm 15 is provided with a pressure relief hole 29. The pressure relief hole 29 is used to prevent the first diaphragm 15 from being damaged by excessive pressure in the cavity 35.

Further, as shown in fig. 2, the microphone chip includes a substrate 11, a second insulating layer 25, a first back plate 19, a first insulating layer 21, and a diaphragm structure 41, which are stacked in this order from bottom to top.

In this embodiment, the substrate 11 may be low-resistance silicon. The base 11 serves as a substrate to support the microphone chip structure. Further, a back cavity 13 is provided on the substrate 11. Specifically, the substrate 11 has a first surface 37 and a second surface 39 facing away from each other. The first surface 37 is located above the second surface 39. The back cavity 13 extends through the first surface 37 and the second surface 39. The back cavity 13 faces the first diaphragm 15. Further, the back cavity 13 is formed by etching on the substrate 11.

Further, as shown in fig. 2, a second insulating layer 25 is disposed between the substrate 11 and the first back plate 19. The second insulating layer 25 is used to support the diaphragm structure 41 and the first backplate 19. Further, the second insulating layer 25 is a second ring structure. The second annular structure has a second central aperture 27.

Further, as shown in fig. 2, the first back plate 19 is disposed on the second insulating layer 25. Further, the first back plate 19 includes a two-layer or more-layer structure. One of the first back plate 19 is a conductive layer. As shown for example in fig. 2, the first back plate 19 comprises a first layer 31 and a second layer 33. The first layer 31 is a conductive layer.

Further, as shown in fig. 2, the first insulating layer 21 is disposed between the first back plate 19 and the diaphragm structure 41. The first insulating layer 21 is used for isolating the first back plate 19 from the diaphragm structure 41. Further, the first insulating layer 21 is a first ring structure. Specifically, the first annular structure has a first central bore 26.

In the present embodiment, the diaphragm structure 41 includes the first diaphragm 15 and the second diaphragm 16 which are independently provided. The second diaphragm 16 is provided at the outer periphery of the first diaphragm 15. And an isolation groove 18 is formed between the first diaphragm 15 and the second diaphragm 16. The isolation groove 18 is rounded, as shown in fig. 3, for example. Of course, the isolation groove 18 is not limited to a circle, but may have other shapes, such as a rectangle, and the application is not limited thereto. Further, as shown in fig. 3, for example, the first diaphragm 15 is circular. The second diaphragm 16 has an annular shape. The first diaphragm 15 is located within an annular second diaphragm 16. Further, the first diaphragm 15 and the second diaphragm 16 are independent of each other, and there is no mutual contact therebetween. In this way, the isolation groove 18 is provided to electrically isolate the first diaphragm 15 from the second diaphragm 16, so that the first diaphragm 15 is electrically disconnected from the peripheral parasitic region (i.e., the second diaphragm 16), thereby reducing the parasitic capacitance to the maximum extent and improving the sensitivity of the microphone. Further, in order to facilitate processing and enable electrical isolation between the first diaphragm 15 and the second diaphragm 16, the width of the isolation groove 18 is greater than 0.1 μm.

Further, in the second embodiment, a second backplate is further disposed above the diaphragm structure 41 to form a dual-backplate microphone chip.

Further, the outer contour size of the second diaphragm 16 is not smaller than the outer contour size of the substrate 11. Preferably, the outer contour dimension of the second diaphragm 16 is equal to the outer contour dimension of the substrate 11. Therefore, the structure of the microphone is more regular, the steps around the first diaphragm 15 are prevented from being increased, and subsequent packaging is facilitated.

Further, the first back plate 19 and the diaphragm structure 41 form a capacitor. Specifically, the first diaphragm 15, the second diaphragm 16, and the first back plate 19 all have a conductive function. The first back plate 19 is disposed opposite to the diaphragm structure 41. Thus, the first back plate 19 and the diaphragm structure 41 form a capacitor plate. Further, a cavity 35 is formed between the first back plate 19 and the first diaphragm 15. Further, the first back plate 19 is provided with a plurality of sound holes 23. The number may be 1 or more.

Further, as shown in fig. 2, on the vertical projection plane, the inner contour of the first ring-shaped structure does not exceed the projection of the first diaphragm 15, so as to fix the first diaphragm 15. Specifically, as shown in fig. 2, for example, the inner diameter of the first center hole 26 is smaller than the outer diameter of the first diaphragm 15. So that on the one hand the first central opening 26 enables a capacitance to be formed between the first back plate 19 and the first diaphragm 15. The first insulating layer 21 can be used for isolating the first back plate 19 from the diaphragm structure 41, and can be used for supporting and fixing the first back plate 19; and on the other hand for fixing the first diaphragm 15. The relatively closed design of the first diaphragm 15 can better improve the low-frequency performance of the device.

The present application further provides a MEMS microphone comprising a microphone chip as described above. Further, the microphone also includes an ASIC (Application specific in-programmed Circuit) chip. The microphone chip and the ASIC chip are connected through a lead.

The application also provides an electronic device, which comprises the microphone and has the characteristics of high sensitivity and easiness in packaging. The electronic equipment is an artificial intelligent terminal product.

It should be noted that, in the description of the present invention, the terms "first", "second", and the like are used for descriptive purposes only and for distinguishing similar objects, and no order is shown between the two, and no indication or suggestion of relative importance is understood. In addition, in the description of the present invention, "a plurality" means two or more unless otherwise specified.

The above-mentioned embodiments, further detailed description of the objects, technical solutions and advantages of the present invention, it should be understood that the above-mentioned embodiments are only specific embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A microphone chip, comprising:

the substrate, the second insulating layer, the vibrating diaphragm structure, the first insulating layer and the first back plate are sequentially stacked from bottom to top;

the diaphragm structure comprises a first diaphragm and a second diaphragm which are independently arranged, the second diaphragm is arranged on the outer periphery of the first diaphragm, and an isolation groove is formed between the first diaphragm and the second diaphragm;

the first insulating layer is of a first annular structure, the second insulating layer is of a second annular structure, and on a vertical projection plane, the inner contour of the first annular structure and/or the inner contour of the second annular structure do not exceed the projection of the first diaphragm.

2. The microphone chip of claim 1, wherein a third diaphragm is further disposed above the first backplate to form a dual-diaphragm microphone chip.

3. The microphone chip of claim 1, wherein the first backplate comprises a two or more layer structure, one of which is a conductive layer.

4. The microphone chip of claim 3, wherein an outer contour of the conductive layer does not exceed an inner contour of the second diaphragm on the vertical projection plane.

5. The microphone chip as recited in claim 1, wherein the substrate has a first surface and a second surface disposed opposite to each other, the substrate being provided with a back cavity extending through the first surface and the second surface, the back cavity facing the first diaphragm.

6. The microphone chip as claimed in claim 5, wherein the outer contour dimension of the second diaphragm is not smaller than the outer contour dimension of the substrate; on the vertical projection plane, the projection of the back cavity is located in the projection of the first diaphragm.

7. Microphone chip according to one of claims 1 to 6, characterized in that the side of the first insulating layer facing the diaphragm structure is embedded in the isolation groove.

8. The microphone chip according to any one of claims 1 to 6, wherein the first back plate is provided with a plurality of sound holes; the projection of the sound holes on the outermost side on the vertical projection plane does not exceed the inner contour of the first annular structure.

9. The microphone chip according to any one of claims 1 to 6, wherein an inner contour of the second diaphragm does not exceed an outer contour of the second annular structure on the vertical projection plane.

10. The microphone chip of any of claims 1 to 6, wherein the isolation trench has a width of less than 5 microns.

11. The microphone chip of any of claims 1 to 6, wherein the isolation trench has a width greater than 0.1 microns.

12. The microphone chip as claimed in any one of claims 1 to 6, wherein a pressure relief hole is formed in the first diaphragm.

13. A microphone chip, comprising:

the substrate, the second insulating layer, the first back plate, the first insulating layer and the vibrating diaphragm structure are sequentially stacked from bottom to top;

the first insulating layer is of a first annular structure, and on a vertical projection plane, the inner contour of the first annular structure does not exceed the projection of the first diaphragm.

14. The microphone chip of claim 13, wherein a second backplate is further disposed above the diaphragm structure to form a dual-backplate microphone chip.

15. The microphone chip of claim 13, wherein the first backplate comprises a two or more layer structure, one of which is a conductive layer.

16. The microphone chip of claim 15, wherein an outer contour of the conductive layer does not exceed an inner contour of the second diaphragm on the vertical projection plane.

17. The microphone chip according to any one of claims 13 to 16, wherein the first backplate is provided with a plurality of sound holes; the projection of the sound holes on the outermost side on the vertical projection plane does not exceed the inner contour of the first annular structure.

18. The microphone chip of any of claims 13 to 16, wherein the isolation trench has a width greater than 0.1 micron.

19. The microphone chip as claimed in any one of claims 13 to 16, wherein a pressure relief hole is formed in the first diaphragm.

20. A MEMS microphone comprising a microphone chip as claimed in any one of claims 1 to 19.

21. An electronic device comprising the microphone of claim 20.