WO2022135213A1 - Mems sensor chip, microphone, and electronic device - Google Patents

Abstract

The present application discloses an MEMS sensor chip, a microphone and an electronic device. The MEMS sensor chip comprises a substrate, a sensing assembly and an annular protective layer; the sensing assembly comprises a first annular support layer, a second annular support layer, a third annular support layer, a first vibrating diaphragm, a second vibrating diaphragm and a back electrode plate; the first annular support layer is provided on the substrate, and the first annular support layer, the first vibrating diaphragm, the second annular support layer, the back electrode plate, the third annular support layer and the second vibrating diaphragm are sequentially stacked; and the annular protective layer is provided on the periphery of the sensing assembly, and the annular protective layer at least covers the first annular support layer and/or the second annular support layer and/or the third annular support layer.

Description

MEMS sensor chips, microphones and electronics

This application claims the priority of the Chinese patent application filed on December 25, 2020 with application number 202023199780.7, the entire contents of which are incorporated herein by reference.

technical field

The present application relates to the field of sensor technology, and in particular, to a MEMS sensor chip, a microphone and an electronic device.

Background technique

MEMS (Micro-Electro-Mechanical System) microphone is an acousto-electric transducer made by micro-machining (MEMS) technology. Because of its small size, good frequency response characteristics and low noise, it is widely used in mobile phones such as mobile phones. , tablet computers, cameras, hearing aids, smart toys and electronic devices such as surveillance devices. The MEMS microphone mainly includes a package shell and a MEMS sensor chip arranged in the package shell, so as to convert the sound signal into an electrical signal through the MEMS sensor chip.

At present, a MEMS sensor chip usually includes a substrate and a sensing component disposed on the substrate. The sensing component includes a diaphragm and a back plate opposite to each other, and a flat capacitive structure composed of the diaphragm and the back plate. Among them, the diaphragm vibrates under the action of sound waves, which causes the distance between the diaphragm and the back plate to change, so that the capacitance of the plate capacitor changes, thereby converting the sound wave signal into an electrical signal.

In the process of preparing MEMS sensor chips, a sacrificial layer (mostly an oxide layer) is set between the sensing component and the substrate, as well as between the diaphragm and the back plate of the sensing component, and then the sacrificial layer is passed through HF acid or BOE. A corrosive solution such as a solution is used to etch away part of the sacrificial layer to release the micro-motor structure; the remaining sacrificial layer is usually used as a support layer of the micro-motor structure to support the induction components.

However, during the etching process, the sacrificial layer is easily etched and transitioned, resulting in lower reliability of the support layer, thereby lowering the reliability of the MEMS sensor chip and the microphone.

technical problem

The main purpose of this application is to propose a MEMS sensor chip, which aims to solve the technical problem of low reliability of the support layer of the micro-motor structure in the existing MEMS sensor chip preparation process.

technical solutions

To achieve the above purpose, the present application proposes a MEMS sensor chip, comprising:

a substrate having a cavity;

an induction assembly, the induction assembly includes a first annular support layer, a second annular support layer, a third annular support layer, a first diaphragm, a second diaphragm and a back plate with a through hole, the first annular support layer is arranged on the substrate, and the first annular support layer, the first diaphragm, the second annular support layer, the back plate, the third annular support layer and the first annular support layer The two diaphragms are sequentially stacked in a direction away from the substrate; and

an annular protective layer, the annular protective layer is arranged on the peripheral side of the induction component, and the annular protective layer at least covers the first annular support layer and/or the second annular support layer and/or the first annular support layer Three annular support layers.

In one embodiment, the annular protective layer sequentially covers the first annular support layer, the first diaphragm, the second annular support layer, the back plate, the third annular support layer, and the the second diaphragm.

In one embodiment, the back plate includes a first conductive layer, an insulating layer and a second conductive layer, the first conductive layer is provided on a side of the second annular support layer away from the substrate, The insulating layer is arranged on the side of the first conductive layer away from the substrate, the second conductive layer is arranged on the side of the insulating layer away from the substrate, and the third annular support layer is provided on the side of the second conductive layer facing away from the substrate; or,

The back plate is a single-layer film structure.

In one embodiment, the annular protective layer is integrally connected with the second diaphragm.

In one embodiment, the annular protective layer is integrally connected with the first diaphragm.

In one embodiment, the first diaphragm has a first annular isolation hole, and the first annular support layer and the second annular support layer are integrally connected through the first annular isolation hole, or the induction The assembly also includes an isolation ring arranged in the first annular isolation hole; or,

The second diaphragm has a second annular isolation hole, and the induction assembly further includes an isolation member, the isolation member is at least partially arranged in the second annular isolation hole.

In one embodiment, the periphery of the first diaphragm is spaced from the annular protective layer, and the first annular support layer and the second annular support layer pass through the periphery of the first diaphragm and the annular protective layer. The spaces between the annular protective layers are integrally connected.

In one embodiment, the periphery of the back plate and the annular protective layer are spaced apart, and the second annular support layer and the third annular support layer pass through the gap between the periphery of the back plate and the annular protective layer. The space between them is connected as a whole.

In one embodiment, the annular protective layer is an insulating protective layer.

In one embodiment, the sensing component further includes a connecting column, the connecting column is movably disposed in the through hole, and two ends of the connecting column are respectively connected to the first diaphragm and the second diaphragm. Two diaphragms.

In one embodiment, the connection post is an electrical connector; or,

The connecting column is an insulating column.

In one embodiment, the first diaphragm is provided with a first pressure relief hole, and/or the second diaphragm is provided with a second pressure relief hole.

The present application also proposes a microphone, comprising:

an encapsulation case; and

In the above-mentioned MEMS sensor chip, the MEMS sensor chip is provided in the package casing.

The present application also proposes an electronic device including the above microphone.

beneficial effect

In the present application, an annular protective layer covering at least the first annular supporting layer and/or the second annular supporting layer and/or the third annular supporting layer is provided on the outside of the induction assembly, so that the annular protective layer can protect the first annular supporting layer and/or the outer periphery of the second annular support layer and/or the third annular support layer is protected to prevent it from being corroded during the manufacturing process, so that the first annular support layer and/or the second annular support layer can be guaranteed or provided and/or the reliability of the third annular support layer, so that the performance and reliability of the microphone can be improved, and the yield of the MEMS sensor chip and the microphone can be improved.

Moreover, by making the induction assembly include a back plate, and a first vibrating film and a second vibrating film distributed on both sides of the back plate, the first vibrating film and the back plate can form a first parallel plate capacitor, The second diaphragm and the back plate form a second parallel plate capacitor, and the first parallel plate capacitor and the second parallel plate capacitor can be differentially controlled, so as to not only improve the sensitivity of the MEMS sensor chip, but also improve the MEMS sensor The signal-to-noise ratio of the chip can improve the performance of the MEMS sensor chip.

Description of drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained according to the structures shown in these drawings without any creative effort.

FIG. 1 is a schematic structural diagram of a first embodiment of a MEMS sensor chip of the present application;

FIG. 2 is a schematic structural diagram of the MEMS sensor chip in FIG. 1 before being etched;

3 is a schematic structural diagram of a second embodiment of the MEMS sensor chip of the present application;

FIG. 4 is a schematic structural diagram of a third embodiment of the MEMS sensor chip of the present application;

5 is a schematic structural diagram of a fourth embodiment of the MEMS sensor chip of the present application;

6 is a schematic structural diagram of a fifth embodiment of the MEMS sensor chip of the present application;

7 is a schematic structural diagram of a sixth embodiment of the MEMS sensor chip of the present application;

8 is a schematic structural diagram of an eighth embodiment of the MEMS sensor chip of the present application;

9 is a schematic structural diagram of a ninth embodiment of the MEMS sensor chip of the present application;

FIG. 10 is a schematic structural diagram of a tenth embodiment of the MEMS sensor chip of the present application.

Description of reference numbers:

label	name	label	name
100	MEMS sensor chip	244	through hole
10	substrate	25	third annular support layer
11	cavity	26	second diaphragm
twenty one	first annular support layer	27	connecting column
twenty two	first diaphragm	28	spacer
twenty three	second annular support layer	30	ring protective layer
twenty four	back plate	31	Limit flanging
241	first conductive layer	a	first sacrificial layer
242	Insulation	b	second sacrificial layer
243	second conductive layer	c	third sacrificial layer

The realization, functional characteristics and advantages of the purpose of the present application will be further described with reference to the accompanying drawings in conjunction with the embodiments.

Embodiments of the present invention

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

It should be noted that if there are descriptions involving "first", "second", etc. in the embodiments of this application, the descriptions of "first", "second", etc. are only used for description purposes, and should not be construed as instructions or Implicit their relative importance or implicitly indicate the number of technical features indicated. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature.

In addition, the meaning of "and/or" in the whole text is to include three parallel schemes. Taking "A and/or B" as an example, it includes scheme A, scheme B, or scheme that A and B satisfy at the same time.

This application proposes a MEMS sensor chip, which is mainly used for microphones.

In an embodiment of the present application, as shown in FIGS. 1 and 3-10 , the MEMS sensor chip 100 includes a substrate 10 , a sensing component and a ring-shaped protective layer 30 .

Wherein, as shown in FIGS. 1 and 3-10 , the substrate 10 has a cavity 11 , and the cavity 11 penetrates the substrate 10 .

Wherein, as shown in FIGS. 1 and 3-10 , the sensing component includes a first annular support layer 21 , a second annular support layer 23 , a third annular support layer 25 , a first diaphragm 22 , and a second diaphragm 26 and a back plate 24 having a through hole 244, the first annular support layer 21 is arranged on the substrate 10, the first diaphragm 22 is arranged on the side of the first annular support layer 21 away from the substrate 10, The second annular support layer 23 is disposed on the side of the first diaphragm 22 away from the substrate 10, the back plate 24 is disposed on the side of the second annular support layer 23 away from the substrate 10, and the first The three annular support layers 25 are disposed on the side of the back plate 24 away from the substrate 10 , and the second diaphragm 26 is disposed on the side of the third annular support layer 25 away from the substrate 10 .

In short, as shown in FIGS. 1 and 3-10 , the first annular support layer 21 is provided on the substrate 10 , the first annular support layer 21 , the first diaphragm 22 , and the second annular support The layer 23 , the back electrode plate 24 , the third annular support layer 25 and the second diaphragm 26 are sequentially stacked in a direction away from the substrate 10 .

Wherein, as shown in FIGS. 1 and 3-10 , the first diaphragm 22 is provided with a first pressure relief hole, and/or the second diaphragm 26 is provided with a second pressure relief hole.

Specifically, the annular hole of the first annular support layer 21 is arranged corresponding to the cavity 11 , and the annular hole of the first annular support layer 21 is communicated with the cavity 11 ; the annular hole of the second annular support layer 23 is connected to the cavity 11 . The annular holes of an annular support layer 21 are arranged correspondingly, the annular holes of the third annular support layer 25 are arranged corresponding to the annular holes of the second annular support layer 23 , and the through holes 244 on the back plate 24 are connected to the third annular support layer. 25 and the ring hole of the second annular support layer 23; and the first pressure relief hole on the first diaphragm 22 communicates with the ring hole of the second annular support layer 23 and the ring hole of the first annular support layer 21 , and/or, the second pressure relief hole on the second diaphragm 26 communicates with the annular hole of the third annular support layer 25 and the external environment.

Specifically, the through hole 244 may be provided in one or a plurality of through holes (ie, greater than or equal to two). In this embodiment, a plurality of the through holes 244 are arranged on the back plate 24 at intervals.

Specifically, the first pressure relief hole and/or the second pressure relief hole may be provided in one or a plurality of holes (ie, greater than or equal to two). In this embodiment, a plurality of the first pressure relief holes are arranged on the first diaphragm 22 at intervals, and/or a plurality of second pressure relief holes are arranged on the second diaphragm 26 at intervals.

Specifically, the diameter or equivalent diameter of the first pressure relief hole and/or the second pressure relief hole may be smaller than the diameter or equivalent diameter of the through hole 244, and the first pressure relief hole and/or the second pressure relief hole may be The number of the two pressure relief holes is less than the number of the through holes 244 .

Specifically, the through holes 244 can be used as sound holes, pressure relief holes and corrosion holes. Specifically, when preparing the MEMS sensor chip 100, the through hole 244 is used as an etching hole for the etching liquid to pass through, so as to facilitate the removal of the second sacrificial layer b and/or the third sacrificial layer c; when assembling the microphone or assembling the microphone When connected to the main control board of the electronic device, the through hole 244 can be used as a pressure relief hole; when working, the through hole 244 can be used as a sound hole for transmitting sound to the first diaphragm 22 and/or the second diaphragm Diaphragm 26 .

Specifically, the first pressure relief hole and/or the second pressure relief hole can also be used as etching holes, so as to allow the etching liquid to pass through when the MEMS sensor chip 100 is prepared. Of course, other dedicated etching channels may also be provided to allow the etching liquid to pass through during the preparation of the MEMS sensor chip 100 .

Wherein, the annular protective layer 30 is provided on the peripheral side of the induction component, and the annular protective layer 30 at least covers the first annular support layer 21 and/or the second annular support layer 23 and/or the third annular support layer Support layer 25 . In this way, it is convenient to protect the first annular support layer 21 and/or the second annular support layer 23 and/or the third annular support layer 25 to ensure/improve the reliability thereof.

Specifically, the first diaphragm 22 and the back plate 24 can form a first parallel plate capacitor, the second diaphragm 26 and the back plate 24 can form a second parallel plate capacitor, and the first parallel plate The capacitor is differentially controlled with the second parallel plate capacitor to improve the performance of the MEMS sensor chip 100 . Specifically, during operation, the first vibrating membrane 22 and the second vibrating membrane 26 vibrate under the action of sound waves, resulting in the gap between the first vibrating membrane 22 and the back plate 24 and the second vibrating membrane 26 and the back plate 24 . The distances of the two are changed, so that the capacitances of the first parallel plate capacitor and the second parallel plate capacitor are changed, so that the acoustic wave signal is converted into two electrical signals.

In order to facilitate the detailed description of the function of the annular protective layer 30, the present application also provides a preparation process of the MEMS sensor chip 100, which is as follows:

1. A first sacrificial layer a, a first vibrating film 22, a second sacrificial layer b, a back plate 24, a third sacrificial layer c and a second vibrating film 26 are sequentially formed (deposited) on the substrate 10, wherein the The back plate 24 is formed with a through hole 244 ; the first diaphragm 22 is formed with a first pressure relief hole, and/or the second diaphragm 26 is formed with a second pressure relief hole.

2. As shown in FIG. 2, the first sacrificial layer a, the first vibrating film 22, the second sacrificial layer b, the back plate 24, the third sacrificial layer c and the peripheral side (deposition) of the second vibrating film 26 are formed The annular protective layer 30 is formed to cover at least the first sacrificial layer a and/or the second sacrificial layer b and/or the third sacrificial layer c.

3. Remove part of the first sacrificial layer a, the second sacrificial layer b and the third sacrificial layer c (by wet etching or vapor phase HF fumigation with corrosive liquids such as HF acid or BOE solution) to release the micro-motor structure; Meanwhile, the remaining first sacrificial layer a forms a first annular supporting layer 21 , the remaining second sacrificial layer b forms a second annular supporting layer 23 , and the remaining third sacrificial layer c forms a third annular supporting layer 25 .

It can be understood that in the process of removing part of the first sacrificial layer a, the second sacrificial layer b and the third sacrificial layer c, since the annular protective layer 30 at least covers the first sacrificial layer a and/or the second sacrificial layer b and/or The third sacrificial layer c, so that the outer periphery of the first sacrificial layer a may not be removed/etched, and/or, the outer periphery of the second sacrificial layer b may not be removed/etched, and/or, may So that the outer periphery of the third sacrificial layer c will not be removed/etched, so that the annular protective layer 30 can achieve the outer periphery of the first sacrificial layer a and/or the second sacrificial layer b and/or the third sacrificial layer c. protection, so that excessive corrosion of the first sacrificial layer a and/or the second sacrificial layer b and/or the third sacrificial layer c can be avoided, thereby ensuring or providing the first annular support layer 21 and/or the second annular support layer 23 and /or the reliability of the third annular support layer 25, so that the performance and reliability of the microphone can be improved, and the yield of the MEMS sensor chip 100 and the microphone can be improved.

That is to say, the annular protective layer 30 can protect the outer periphery of the first annular support layer 21 and/or the second annular support layer 23 and/or the third annular support layer 25 from being corroded during the preparation process, As a result, the reliability of the first annular support layer 21 and/or the second annular support layer 23 and/or the third annular support layer 25 can be guaranteed or provided, so that the performance and reliability of the microphone can be improved, and the MEMS sensor chip 100 and the microphone can be improved. yield rate.

Moreover, by making the induction assembly include the back plate 24 and the first diaphragm 22 and the second diaphragm 26 distributed on both sides of the back plate 24, the first diaphragm 22 and the back plate 24 can be formed. The first parallel plate capacitor, the second diaphragm 26 and the back plate 24 form a second parallel plate capacitor, and by differentially controlling the first parallel plate capacitor and the second parallel plate capacitor, not only can the MEMS sensor chip 100 be improved The sensitivity of the MEMS sensor chip 100 can be improved, and the signal-to-noise ratio of the MEMS sensor chip 100 can be improved, so that the performance of the MEMS sensor chip 100 can be improved.

In this embodiment, the annular protective layer 30 covers at least the first annular support layer 21 , the second annular support layer 23 and the third annular support layer 25 to ensure the first annular support layer 21 and the second annular support layer Reliability of layer 23 and third annular support layer 25.

Further, as shown in FIGS. 1 and 3-10 , the sensing component further includes a connecting column 27 , the connecting column 27 is movably disposed in the through hole 244 , and both ends of the connecting column 27 The first diaphragm 22 and the second diaphragm 26 are respectively connected, so that the first diaphragm 22 and the second diaphragm 26 can be mechanically coupled.

Specifically, the peripheral surface of the connecting column 27 at the through hole 244 should be spaced or slidably connected to the inner wall surface of the through hole 244 , so that the connecting column 27 can be movably disposed in the through hole 244 .

In a specific embodiment, the connecting post 27 can be an electrical connector to electrically connect the first diaphragm 22 and the second diaphragm 26, so that the first diaphragm 22 and the second diaphragm 26 can also be electrically coupled It can also be that the connecting column 27 is an insulating column, so that the first vibrating film 22 and the second vibrating film 26 are only mechanically coupled; specifically, according to the connection between the annular protective layer 30 and the first vibrating film 22 and the second vibrating film 26 relationship is set.

In some embodiments, as shown in FIGS. 8 , 9 and 10 , the outer annular surface of the annular protective layer 30 may be a stepped surface. In this part of the embodiments, in one embodiment, the outer peripheries of the third annular support layer 25 , the second diaphragm 26 and the back plate 24 can be flush, and the second annular support layer 23 radially (ie, in the direction away from the centerline of the substrate 10 ) protruding from the back plate 24 , the first diaphragm 22 protrudes radially (ie, in the direction away from the centerline of the substrate 10 ) from the second annular support layer 23, the first annular support layer 21 protrudes from the first diaphragm 22 radially (ie, in the direction away from the centerline of the substrate 10), so that the shape of the peripheral side of the induction component is a stepped structure, and the The shape of the annular protective layer 30 is suitable for the shape of the peripheral side of the induction component, so that the thickness of the annular protective layer 30 is relatively uniform to ensure the protection effect, that is, the outer annular surface of the annular protective layer 30 can be a stepped surface .

In this part of the embodiments, in one embodiment, the third annular support layer 25 can also be made to protrude from the second diaphragm 26 radially (ie, in the direction away from the centerline of the substrate 10 ), and the back pole The plate 24 protrudes radially (ie, in a direction away from the centerline of the substrate 10 ) beyond the third annular support layer 25 , which protrudes radially (ie, in a direction away from the centerline of the substrate 10 ) Protruding from the back plate 24 , the first diaphragm 22 protrudes from the second annular support layer 23 radially (ie, in the direction away from the centerline of the substrate 10 ), and the first annular support layer 21 radially (that is, in the direction away from the centerline of the substrate 10) protruding from the first diaphragm 22, so that the shape of the peripheral side of the induction component is a stepped structure, and the shape of the annular protective layer 30 is the same as that of the peripheral side of the induction component. The shape is suitable, so that the thickness of the annular protective layer 30 is relatively uniform to ensure the protection effect, that is, the outer annular surface of the annular protective layer 30 can be a stepped surface.

In yet another embodiment, as shown in FIGS. 1 and 3-7 , the outer ring surface of the annular protective layer 30 may be a flat surface. In this part of the embodiment, the outer peripheries of the first annular supporting layer 21 , the first diaphragm 22 , the second annular supporting layer 23 , the third annular supporting layer 25 and the second diaphragm 26 can be flush, so as to The outer annular surface of the annular protective layer 30 is made a flat surface.

In a specific embodiment, as shown in FIG. 1 , the annular protective layer 30 can cover the first annular support layer 21 , the first diaphragm 22 , the second annular support layer 23 , the first annular support layer 21 , the first annular diaphragm 22 , the second annular support layer 23 , The back plate 24 , the third annular support layer 25 and the second diaphragm 26 . Specifically, one end of the annular protective layer 30 is hermetically connected to the upper surface of the substrate 10 , and the other end covers the second diaphragm 26 .

In a specific embodiment, the first vibrating membrane 22 and the second vibrating membrane 26 can be selected as single-layer membrane structures, and the materials thereof are all conductive materials, such as polysilicon.

In a specific embodiment, the material of the annular protective layer 30 may be the same as the material of the second diaphragm 26 (for example, both can be selected as polysilicon, etc.), or may be different from the material of the second back plate 24 (for example, annular The protective layer 30 is made of insulating materials, such as silicon nitride, and the vibrating film is made of polysilicon); but it should be different from the materials of the first sacrificial layer a, the second sacrificial layer b and the third sacrificial layer c (such as the first sacrificial layer The layer a and/or the second sacrificial layer b and/or the second sacrificial layer b may be selected from silicon oxide, etc.) to prevent the ring-shaped protective layer 30 from being corroded during the preparation process, which will be described with examples below.

In a specific embodiment, the back plate 24 can either be a single-layer conductive layer structure, such as a single-layer film structure, or a three-layer film structure. The conductive layer 241 , the insulating layer 242 and the second conductive layer 243 , and the through hole 244 penetrates the first conductive layer 241 , the insulating layer 242 and the second conductive layer 243 in sequence.

It should be noted that, when the back plate 24 is configured as a three-layer film structure, the first conductive layer 241 can be provided on the side of the second annular support layer 23 away from the substrate 10, and the insulating layer 242 is provided on the side of the first conductive layer 241 away from the substrate 10, the second conductive layer 243 is provided on the side of the insulating layer 242 away from the substrate 10, and the third annular support layer 25 is provided on the second The side of the conductive layer 243 away from the substrate 10; and the first conductive layer 241 and the first diaphragm 22 can form a first parallel plate capacitor, and the second conductive layer 243 and the second diaphragm 26 can form a second parallel plate capacitor.

In a specific embodiment, the annular protective layer 30 may be integrally connected with the second diaphragm 26, or the annular protective layer 30 may be connected with the second diaphragm 26 separately (in this case, the annular protective layer 30 is an insulating protective layer to prevent the first vibrating film 22, the back plate 24 and the second vibrating film 26 from being short-circuited through the annular protective layer 30), so as to realize the differential control of the first parallel plate capacitor and the second parallel plate capacitor respectively, Examples are given below.

It should be pointed out that when the annular protective layer 30 is integrally connected with the second diaphragm 26, the periphery of the back plate 24 can be spaced from (the inner surface of) the annular protective layer 30 to prevent the back plate 24 from passing through the annular protective layer. 30 is short-circuited with the first diaphragm 22 and/or the second diaphragm 26 .

In some embodiments, as shown in FIGS. 1 and 3-7 , the annular protective layer 30 is integrally connected with the second diaphragm 26 . In this way, when the second diaphragm 26 is formed (deposited), the annular protective layer 30 can be formed (deposited) together, thereby simplifying the fabrication process of the MEMS sensor chip 100 .

In the first embodiment of the MEMS sensor chip 100 of the present application, as shown in FIG. 1 , the annular protective layer 30 is integrally connected with the second diaphragm 26 . Specifically, the materials of the annular protective layer 30 and the second diaphragm 26 are both conductive materials, such as polysilicon.

In this embodiment, specifically, as shown in FIG. 1 , the annular protective layer 30 is integrally connected with the first diaphragm 22 . Wherein, the material of the first vibrating film 22 is a conductive material, such as polysilicon.

In this embodiment, further, as shown in FIG. 1 , the periphery of the back plate 24 is spaced from (the inner surface of) the annular protective layer 30 to prevent the back plate 24 from passing through the annular protective layer 30 and the first The diaphragm 22 and/or the second diaphragm 26 are short-circuited.

In this embodiment, specifically, as shown in FIG. 1 , the second annular support layer 23 and the third annular support layer 25 are connected as a whole through the interval between the periphery of the back plate 24 and the annular protective layer 30 . In this way, the reliability of the second annular support layer 23 and the third annular support layer 25 can be improved.

In this embodiment, further, as shown in FIG. 1 , the back plate 24 includes a first conductive layer 241 , an insulating layer 242 and a second conductive layer 243 that are stacked in sequence, and the through holes 244 pass through the first conductive layer in sequence. 241, an insulating layer 242 and a second conductive layer 243, and the first conductive layer 241 is provided on the side of the second annular support layer 23 away from the substrate 10, and the insulating layer 242 is provided on the side of the first conductive layer 241 On the side facing away from the substrate 10 , the second conductive layer 243 is provided on the side of the insulating layer 242 facing away from the substrate 10 , and the third annular support layer 25 is provided on the side of the second conductive layer 243 facing away from the substrate 10 . side.

In this way, since the insulating layer 242 is disposed between the first conductive layer 241 and the second conductive layer 243, the short circuit between the first conductive layer 241 and the second conductive layer 243 can be avoided, so that the first conductive layer 241 and the first diaphragm can be connected. 22 forms a first parallel plate capacitor, and the second conductive layer 243 and the second diaphragm 26 form a second parallel plate capacitor.

In this embodiment, further, as shown in FIG. 1 , the sensing assembly further includes a connecting column 27 , the connecting column 27 is movably disposed in the through hole 244 , and two of the connecting column 27 The ends are respectively connected to the first diaphragm 22 and the second diaphragm 26 .

In this embodiment, further, as shown in FIG. 1 , the connecting column 27 is an electrical connecting member to electrically connect the first vibrating film 22 and the second vibrating film 26 .

In this embodiment, in an embodiment, as shown in FIG. 1 , the first annular supporting layer 21 , the first diaphragm 22 , the second annular supporting layer 23 , the third annular supporting layer 25 and the The outer periphery of the dither diaphragm 26 is flush, so that the outer ring surface of the annular protective layer 30 is a flat surface.

In the second embodiment of the MEMS sensor chip 100 of the present application, as shown in FIG. 3 , the difference between this embodiment and the first embodiment of the MEMS sensor chip 100 of the present application is that, in this embodiment, the connection Post 27 is an insulating member.

In the third embodiment of the MEMS sensor chip 100 of the present application, as shown in FIG. 4 , the difference between this embodiment and the first embodiment of the MEMS sensor chip 100 of the present application is that the first parallel plate capacitor and the first parallel plate capacitor are specifically formed. Two parallel plate capacitors work differently.

In this embodiment, as shown in FIG. 4 , one end of the annular protective layer 30 is integrally connected with the second diaphragm 26, and the other end of the annular protective layer 30 is integrally connected with the first diaphragm 22; the The back electrode plate 24 is a single-layer film structure, and the periphery of the back electrode plate 24 is spaced from (the inner surface of the annular protective layer 30 ), and the second annular support layer 23 and the third annular support layer 25 pass through the back electrode The peripheral edge of the plate 24 is integrally connected with the space between the annular protective layer 30 .

As shown in FIG. 4 , the second diaphragm 26 has a second annular isolation hole, and the sensing assembly further includes an isolation member 28 , and the isolation member 28 is at least partially disposed in the second annular isolation hole; and when the When the sensing assembly includes the connecting column 27, the connecting column 27 is an insulating column. Specifically, the spacer 28 is made of insulating material, such as silicon nitride.

In this way, due to the provision of the second annular isolation hole, the short circuit between the first diaphragm 22 and the second diaphragm 26 through the annular protective layer 30 can be avoided, so that the back plate 24 and the first diaphragm 22 can form a first parallel plate capacitor , the back plate 24 and the second diaphragm 26 form a second parallel plate capacitor.

In this embodiment, in one embodiment, as shown in FIG. 4 , the cross-sectional shape of the spacer 28 is T-shaped.

In this embodiment, in one embodiment, the spacer 28 is an annular structure.

In the fourth embodiment of the MEMS sensor chip 100 of the present application, as shown in FIG. 5 , the difference between this embodiment and the third embodiment of the MEMS sensor chip 100 of the present application is that, in this embodiment, the back The electrode plate 24 has a three-layer film structure, that is, the back electrode plate 24 includes a first conductive layer 241, an insulating layer 242 and a second conductive layer 243 that are stacked in sequence, and the through holes 244 run through the first conductive layer 241 and the insulating layer 242 in sequence. and the second conductive layer 243, so that the first conductive layer 241 and the first diaphragm 22 can form a first parallel plate capacitor, and the second conductive layer 243 and the second diaphragm 26 can form a second parallel plate capacitor.

In the fifth embodiment of the MEMS sensor chip 100 of the present application, as shown in FIG. 6 , the difference between this embodiment and the first embodiment of the MEMS sensor chip 100 of the present application is that the first parallel plate capacitor and the first parallel plate capacitor are specifically formed. Two parallel plate capacitors work differently.

In this embodiment, as shown in FIG. 1 , the annular protective layer 30 is integrally connected with the second diaphragm 26 , the back plate 24 is a single-layer film structure, and the periphery of the back plate 24 is connected to the annular The protective layer 30 (the inner surface) is arranged at intervals, and the second annular supporting layer 23 and the third annular supporting layer 25 are connected as a whole through the interval between the periphery of the back plate 24 and the annular protective layer 30; and when the When the sensing assembly includes the connecting column 27, the connecting column 27 is an insulating column. Specifically, the spacer 28 is made of insulating material, such as silicon nitride.

In this way, since the periphery of the back plate 24 is spaced from (the inner surface of) the annular protective layer 30, the first diaphragm 22 and the second diaphragm 26 can be prevented from being short-circuited through the annular protective layer 30, so that the back plate 24 can be prevented from being short-circuited. 24 and the first diaphragm 22 form a first parallel plate capacitor, and the back plate 24 and the second diaphragm 26 form a second parallel plate capacitor.

In the sixth embodiment of the MEMS sensor chip 100 of the present application, as shown in FIG. 7 , the difference between this embodiment and the first embodiment of the MEMS sensor chip 100 of the present application is that in this embodiment, the back The electrode plate 24 has a three-layer film structure, that is, the back electrode plate 24 includes a first conductive layer 241, an insulating layer 242 and a second conductive layer 243 that are stacked in sequence, and the through holes 244 run through the first conductive layer 241 and the insulating layer 242 in sequence. and the second conductive layer 243, so that the first conductive layer 241 and the first diaphragm 22 can form a first parallel plate capacitor, and the second conductive layer 243 and the second diaphragm 26 can form a second parallel plate capacitor.

In the seventh embodiment of the MEMS sensor chip 100 of the present application, the difference between this embodiment and the first embodiment of the MEMS sensor chip 100 of the present application mainly lies in the specific manner of forming the first parallel plate capacitor and the second parallel plate capacitor different.

In this embodiment, one end of the annular protective layer 30 is integrally connected with the second diaphragm 26 , and the other end of the annular protective layer 30 is integrally connected with the first diaphragm 22 ; The second annular support layer 23 and the third annular support layer 25 are connected as a whole through the interval between the periphery of the back plate 24 and the annular protection layer 30; and all The first diaphragm 22 has a first annular isolation hole, and the first annular support layer 21 and the second annular support layer 23 are integrally connected through the first annular isolation hole. The isolation ring in the isolation hole is an insulating ring.

In this way, by arranging the first annular isolation hole, the first diaphragm 22 and the second diaphragm 26 can be prevented from being short-circuited through the annular protective layer 30, and by making the periphery of the back plate 24 and the annular protective layer 30 (the inner surface) The back plate 24 and the first diaphragm 22 can form a first parallel plate capacitor, and the back plate 24 and the second diaphragm 26 can form a second parallel plate capacitor.

In this embodiment, specifically, the back plate 24 can be a single-layer film structure or a three-layer film structure; and when the sensing component includes a connecting column 27 , the connecting column 27 is an insulating column. Specifically, the spacer 28 is made of insulating material, such as silicon nitride.

In yet another embodiment, as shown in FIGS. 8-10 , the annular protective layer 30 can be an insulating protective layer to prevent the first diaphragm 22 , the back plate 24 and the second diaphragm 26 from passing through the annular protective layer 30 short circuit.

In the eighth embodiment of the MEMS sensor chip 100 of the present application, as shown in FIG. 8 , the diaphragm is an insulating protective layer, one end of the insulating protective layer is connected to the side surface of the substrate 10 , and the other end is connected to the second Diaphragm 26.

In this embodiment, as shown in FIG. 8 , the back plate 24 has a three-layer film structure, that is, the back plate 24 includes a first conductive layer 241 , an insulating layer 242 and a second conductive layer 243 that are stacked in sequence. , the through hole 244 penetrates the first conductive layer 241, the insulating layer 242 and the second conductive layer 243 in sequence, and the first conductive layer 241 is provided on the side of the second annular support layer 23 away from the substrate 10, the insulating layer 241 The layer 242 is provided on the side of the first conductive layer 241 away from the substrate 10, the second conductive layer 243 is provided on the side of the insulating layer 242 away from the substrate 10, and the third annular support layer 25 is provided on the side of the insulating layer 242 away from the substrate 10. The side of the second conductive layer 243 facing away from the substrate 10 .

In this way, since the insulating layer 242 is disposed between the first conductive layer 241 and the second conductive layer 243, the short circuit between the first conductive layer 241 and the second conductive layer 243 can be avoided, so that the first conductive layer 241 and the first diaphragm can be connected. 22 forms a first parallel plate capacitor, and the second conductive layer 243 and the second diaphragm 26 form a second parallel plate capacitor.

In this embodiment, specifically, as shown in FIG. 8 , one end of the annular protective layer 30 is provided with a limiting flange 31 , and the limiting flange 31 is provided on a side of the second diaphragm 26 away from the substrate 10 . side.

In this embodiment, further, as shown in FIG. 8 , the sensing component further includes a connecting column 27 , the connecting column 27 is movably disposed in the through hole 244 , and two of the connecting column 27 The ends are respectively connected to the first diaphragm 22 and the second diaphragm 26 to achieve mechanical coupling.

In this embodiment, further, as shown in FIG. 8 , the connecting column 27 is an electrical connecting piece to electrically connect the first vibrating film 22 and the second vibrating film 26 to realize electrical coupling. Specifically, both ends of the connecting column 27 are integrally connected to the first diaphragm 22 and the second diaphragm 26 respectively.

In this embodiment, further, as shown in FIG. 8 , the outer annular surface of the annular protective layer 30 is a stepped surface. Specifically, the third annular support layer 25 protrudes from the second diaphragm 26 radially (ie, in the direction away from the centerline of the substrate 10 ), and the back plate 24 radially (ie, in the direction away from the centerline of the substrate 10 ) direction) protrudes from the third annular support layer 25, the second annular support layer 23 protrudes from the back plate 24 radially (ie in the direction away from the centerline of the substrate 10), the first vibration The membrane 22 protrudes radially (ie, in a direction away from the centerline of the substrate 10 ) beyond the second annular support layer 23 , which is radially (ie, in a direction away from the centerline of the substrate 10 ) Protruding from the first diaphragm 22 . In this way, the shape of the peripheral side of the induction component is a stepped structure, and the shape of the annular protective layer 30 is suitable for the shape of the peripheral side of the induction component, so that the thickness of the annular protective layer 30 is relatively uniform to ensure the protection effect.

In the ninth embodiment of the MEMS sensor chip 100 of the present application, as shown in FIG. 9 , the difference between this embodiment and the eighth embodiment of the MEMS sensor chip 100 of the present application is that, in this embodiment, the connection Post 27 is an insulating member.

In the tenth embodiment of the MEMS sensor chip 100 of the present application, as shown in FIG. 10 , the difference between this embodiment and the ninth embodiment of the MEMS sensor chip 100 of the present application is that, in this embodiment, the back The electrode plate 24 is a single-layer film structure.

Of course, in specific embodiments, the annular protective layer 30 can also be set to other structural forms, so as to achieve "at least covering the first annular support layer 21 and/or the second annular support layer 23 and/or the third annular support layer" Layer 25".

For example, the annular protection layer 30 may include a first protection ring layer and a second protection ring layer, wherein the first protection ring layer covers the first annular support layer 21 and the second protection ring layer covers the second annular support layer 23 and the third annular support layer 25; and so on.

In addition, it should be noted that the technical solutions between the above embodiments can be combined with each other, but must be based on the realization by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be realized, it should be considered that this The combination of these technical solutions does not exist and is not within the scope of protection claimed in this application.

The present application also proposes a microphone, comprising:

an encapsulation case; and

In the above-mentioned MEMS sensor chip, the MEMS sensor chip is provided in the package casing.

The specific structure of the MEMS sensor chip refers to the above-mentioned embodiments. Since the microphone of the present application adopts all the technical solutions of all the above-mentioned embodiments, it at least has all the functions brought by the technical solutions of the above-mentioned embodiments, and will not be repeated here. .

The present application also proposes an electronic device, which includes a main control board and a microphone, and the microphone is electrically connected to the main control board. The specific structure of the microphone refers to the above-mentioned embodiments. Since the electronic device of the present application adopts all the technical solutions of the above-mentioned embodiments, it at least has all the functions brought by the technical solutions of the above-mentioned embodiments, and will not be repeated here.

Wherein, the electronic device can be selected from electronic devices such as a mobile phone, a tablet computer, a camera, a hearing aid, a smart toy or a listening device.

The above descriptions are only optional embodiments of the present application, and are not intended to limit the patent scope of the present application. Under the inventive concept of the present application, any equivalent structural transformations made by using the contents of the description and drawings of the present application, or direct/indirect Applications in other related technical fields are included in the scope of patent protection of this application.

Claims (14)

1. A MEMS sensor chip, comprising:

   a substrate having a cavity;

   an induction assembly, the induction assembly includes a first annular support layer, a second annular support layer, a third annular support layer, a first diaphragm, a second diaphragm and a back plate with a through hole, the first annular support layer is arranged on the substrate, and the first annular support layer, the first diaphragm, the second annular support layer, the back plate, the third annular support layer and the first annular support layer The two diaphragms are sequentially stacked in a direction away from the substrate; and

   an annular protective layer, the annular protective layer is arranged on the peripheral side of the induction component, and the annular protective layer at least covers the first annular support layer and/or the second annular support layer and/or the first annular support layer Three annular support layers.
2. The MEMS sensor chip according to claim 1, wherein the annular protective layer sequentially covers the first annular support layer, the first diaphragm, the second annular support layer, the back plate, the the third annular support layer and the second diaphragm.
3. The MEMS sensor chip according to claim 2, wherein the back plate comprises a first conductive layer, an insulating layer and a second conductive layer, and the first conductive layer is provided at a position away from the second annular support layer. one side of the substrate, the insulating layer is arranged on the side of the first conductive layer away from the substrate, and the second conductive layer is arranged on the side of the insulating layer away from the substrate , the third annular support layer is provided on the side of the second conductive layer away from the substrate; or,

   The back plate is a single-layer film structure.
4. The MEMS sensor chip of claim 3, wherein the annular protective layer is integrally connected with the second diaphragm.
5. The MEMS sensor chip of claim 4, wherein the annular protective layer is integrally connected with the first diaphragm.
6. The MEMS sensor chip of claim 5, wherein the first diaphragm has a first annular isolation hole, and the first annular support layer and the second annular support layer are integrated through the first annular isolation hole connected, or, the induction assembly further includes an isolation ring arranged in the first annular isolation hole; or,

   The second diaphragm has a second annular isolation hole, and the induction assembly further includes an isolation member, the isolation member is at least partially arranged in the second annular isolation hole.
7. The MEMS sensor chip according to claim 4, wherein the periphery of the first diaphragm is spaced from the annular protective layer, and the first annular support layer and the second annular support layer pass through the first annular support layer. The periphery of the diaphragm is integrally connected with the space between the annular protective layers.
8. The MEMS sensor chip according to claim 4, wherein the periphery of the back plate is spaced from the annular protective layer, and the second annular support layer and the third annular support layer pass through the periphery of the back plate It is integrated with the space between the annular protective layers.
9. The MEMS sensor chip of claim 3, wherein the annular protective layer is an insulating protective layer.
10. The MEMS sensor chip according to any one of claims 1 to 9, wherein the sensing component further comprises a connection post, the connection post is movably disposed in the through hole, and two of the connection post The ends are respectively connected to the first vibrating film and the second vibrating film.
11. The MEMS sensor chip of claim 10 , wherein the connection posts are electrical connectors; or,

    The connecting column is an insulating column.
12. The MEMS sensor chip according to any one of claims 1 to 9, wherein a first pressure relief hole is formed on the first diaphragm, and/or a second pressure relief hole is formed on the second diaphragm Press the hole.
13. A microphone comprising:

    an encapsulation case; and

    The MEMS sensor chip according to any one of claims 1 to 12, wherein the MEMS sensor chip is provided in the package housing.
14. An electronic device comprising the microphone of claim 13 .