CN213694153U

CN213694153U - Back electrode plate structure, MEMS sensor and electronic equipment

Info

Publication number: CN213694153U
Application number: CN202023090937.2U
Authority: CN
Inventors: 刘松; 周宗燐; 邱冠勋
Original assignee: Qingdao Goertek Intelligent Sensor Co Ltd
Current assignee: Qingdao Goertek Intelligent Sensor Co Ltd
Priority date: 2020-12-18
Filing date: 2020-12-18
Publication date: 2021-07-13
Anticipated expiration: 2030-12-18

Abstract

The utility model discloses a back of body polar plate structure, MEMS sensor and electronic equipment. Wherein, this back plate structure includes: a first insulating layer; the conducting layer covers the surface of the first insulating layer, one side of the conducting layer, facing the first insulating layer, is provided with a protruding structure, and the protruding structure penetrates through the first insulating layer; and the second insulating layer covers one side of the conducting layer, which is back to the first insulating layer. The utility model discloses technical scheme's back of the body polar plate structure can avoid appearing the phenomenon of conducting layer short circuit, inefficacy.

Description

Back electrode plate structure, MEMS sensor and electronic equipment

Technical Field

The utility model relates to a microphone technical field, in particular to back of body polar plate structure, MEMS sensor and electronic equipment.

Background

The back plate of the microphone in the related art generally forms a capacitance system with the diaphragm, and when the diaphragm vibrates, the capacitance of the capacitance system changes due to the change of the distance between the diaphragm and the back plate, so that sound wave signals are converted into different electric signals, and the corresponding functions of the microphone are realized. However, in the conventional back plate, the conductive layer is mostly exposed at a side facing the diaphragm or a side opposite to the diaphragm, which causes a phenomenon that foreign matters fall on the conductive layer to cause short circuit and failure.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a back of body polar plate structure aims at avoiding appearing the phenomenon of conducting layer short circuit, inefficacy.

In order to achieve the above object, the utility model provides a back plate structure, include:

a first insulating layer;

the conducting layer covers the surface of the first insulating layer, a protruding structure is arranged on the surface, facing the first insulating layer, of the conducting layer, and the protruding structure penetrates through the first insulating layer; and

and the second insulating layer covers the surface of the conducting layer, which is opposite to the first insulating layer.

Optionally, the second insulating layer is the same or different in thickness from the first insulating layer.

Optionally, the first insulating layer and/or the second insulating layer is a silicon nitride layer or a silicon oxide layer.

Optionally, the first insulating layer is provided with a yielding hole, and the protruding structure passes through the yielding hole and is attached to the hole wall of the yielding hole.

Optionally, the material of the protruding structure is a conductor material.

Optionally, the protruding structures are arranged in a tapered shape, and the cross-sectional area gradually decreases in a direction away from the conductive layer.

Optionally, the conductive layer includes a non-sensitive region and a sensitive region, a gap is formed between the non-sensitive region and the sensitive region, and the protruding structure is disposed in the non-sensitive region.

Optionally, the number of the sensitive areas and the number of the non-sensitive areas are both multiple, and the multiple sensitive areas and the multiple non-sensitive areas are sequentially and alternately arranged.

The utility model also provides an MEMS sensor, which comprises;

a substrate;

the vibrating diaphragm is arranged on the surface of the substrate; and

the back plate structure is arranged on one side, back to the substrate, of the vibrating diaphragm and comprises a first insulating layer, a conducting layer and a second insulating layer; the conducting layer covers the surface of the first insulating layer, a protruding structure is arranged on the surface, facing the first insulating layer, of the conducting layer, and the protruding structure penetrates through the first insulating layer; the second insulating layer covers the surface of the conducting layer, which is opposite to the first insulating layer; the first insulating layer is arranged facing the vibrating diaphragm, a vibrating gap is formed between the first insulating layer and the vibrating diaphragm, and the protruding structure extends into the vibrating gap.

The utility model also provides an electronic equipment, be in including equipment body and setting MEMS sensor on the equipment body, the MEMS sensor includes:

a substrate;

the vibrating diaphragm is arranged on the surface of the substrate; and

The utility model discloses technical scheme's back of body polar plate structure is through covering the surface on the first insulation layer with the conducting layer to through covering the second insulating layer in the conducting layer one side on the conducting layer back to the first insulation layer, promptly, first insulation layer and second insulating layer are located the both sides surface that the conducting layer is relative respectively, so make the conducting layer wrap up by two-layer insulating layer and form the protection, thereby effectually prevent that the foreign matter from falling on the surface of conducting layer, avoid the conducting layer short circuit, the phenomenon of inefficacy to appear. Furthermore, in the technical scheme of the application, the protruding structure is arranged on the conductive layer and penetrates out of the first insulating layer, so that the protruding structure is not easily corroded by corrosive liquid in a subsequent corrosion process, and the structural integrity of the protruding structure is ensured.

Drawings

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

Fig. 1 to 5 are schematic cross-sectional views of the MEMS sensor according to the present invention in various production states;

fig. 6 is a schematic cross-sectional view of an embodiment of the MEMS sensor of the present invention.

The reference numbers illustrate:

reference numerals	Name (R)	Reference numerals	Name (R)
				10	Back electrode plate structure	11	A first insulating layer
111	Passing hole	12	Conductive layer
				12a	Non-sensitive area	12b	Sensitive area
121	Bump structure	13	A second insulating layer
				20	Substrate	21	Back cavity
30	Vibrating diaphragm	40	Vibration gap
				50	Sacrificial layer	100	MEMS sensor

The objects, features and advantages of the present invention will be further described with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely 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, 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 belong to the protection scope of the present invention.

It should be noted that all the directional indicators (such as upper, lower, left, right, front and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is changed accordingly.

In the present application, unless expressly stated or limited otherwise, the terms "connected" and "fixed" are to be construed broadly, e.g., "fixed" may be fixedly connected or detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In addition, descriptions in the present application as to "first", "second", and the like are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit to the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and/or" appearing throughout is to include three juxtapositions, exemplified by "A and/or B," including either the A or B arrangement, or both A and B satisfied arrangement. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should not be considered to exist, and is not within the protection scope of the present invention.

The utility model provides a back polar plate structure 10.

Referring to fig. 6, in the embodiment of the present invention, the back plate structure 10 includes:

a first insulating layer 11;

the conductive layer 12 covers the surface of the first insulating layer 11, a protruding structure 121 is arranged on the surface of the conductive layer 12 facing the first insulating layer 11, and the protruding structure 121 penetrates through the first insulating layer 11; and

and the second insulating layer 13 covers the surface of the conducting layer 12, which is opposite to the first insulating layer 11.

In practical applications, after the first insulating layer 11 is formed, the conductive layer 12 may be formed on the upper surface of the first insulating layer 11 by deposition, and then the second insulating layer 13 is formed on the upper surface of the conductive layer 12 by deposition, so that the first insulating layer 11, the conductive layer 12 and the second insulating layer 13 are sequentially stacked, and the conductive layer 12 is protected by the outer insulating layer in the middle.

The conductive layer 12 may be a polysilicon layer or a metal layer, which when energized may be used to attract the diaphragm 30 of the microphone, thereby converting into a different electrical signal through a change in capacitance. In the embodiment of the present application, the thickness of the conductive layer 12 may be set to 0.5 μm to ensure good conductivity of the conductive layer 12.

The protrusion structure 121 is mainly used in a microphone, and is used to prevent the diaphragm 30 of the microphone from receiving sound waves and vibrating toward the back plate structure 10, and the diaphragm 30 is attached to the back plate structure 10, thereby preventing the microphone from failing. It can be understood that, in the embodiment of the present application, the number of the protruding structures 121 may be multiple, the multiple protruding structures 121 are uniformly spaced from each other, and centers of the multiple protruding structures 121 are located on the same straight line, such an arrangement enables the diaphragm 30 to be prevented from adhering to the back plate structure 10 by stopping the multiple protruding structures 121 when the diaphragm 30 vibrates, and the stress of the diaphragm 30 is relatively uniform and distributed.

Therefore, the utility model discloses technical scheme's back plate structure 10 is through covering conducting layer 12 on the surface of first insulating layer 11 to through covering second insulating layer 13 in the conducting layer 12 one side of carrying away from first insulating layer 11, promptly, first insulating layer 11 and second insulating layer 13 are located the relative both sides surface of conducting layer 12 respectively, so make conducting layer 12 wrap up by two-layer insulating layer and form the protection, thereby the effectual foreign matter that prevents falls in the surface of conducting layer 12, avoid conducting layer 12 to appear short circuit, the phenomenon of inefficacy. Further, in the technical scheme of the application, the protruding structure 121 is disposed on the conductive layer 12, and the protruding structure 121 penetrates out of the first insulating layer 11, so that the protruding structure 121 is not easily corroded by a corrosive liquid in a subsequent corrosion process, and the structural integrity of the protruding structure 121 is ensured.

Further, in an embodiment of the present application, the second insulating layer 13 and the first insulating layer 11 have the same thickness. In this embodiment, the thickness of the first insulating layer 11 and the second insulating layer 13 may range in value from 1 μm to 2 μm. The thicknesses of the first insulating layer 11 and the second insulating layer 13 are not too thick or too thin, and if the thicknesses of the first insulating layer 11 and the second insulating layer 13 are too thin, the impact of the diaphragm 30 is easily damaged; if the thickness is too thick, the micro-design of the microphone is not facilitated. In this embodiment, the thicknesses of the first insulating layer 11 and the second insulating layer 13 may be 1 μm or 1.5 μm, and the design that the thicknesses of the two layers are the same can make the thicknesses of the upper and lower sides of the conductive layer 12 uniform, so that the stress on the two sides of the conductive layer 12 is more uniform, and the sensing of capacitance change caused by vibration is facilitated. Of course, in the actual design, the thicknesses of the first insulating layer 11 and the second insulating layer 13 may be designed to be different.

In an embodiment of the back plate structure 10 of the present application, the first insulating layer 11 and/or the second insulating layer 13 are silicon nitride layers. Silicon nitride is very strong, especially hot pressed silicon nitride, and is one of the hardest substances in the world. The high-temperature-resistant aluminum alloy is extremely high-temperature-resistant, the strength can be maintained to 1200 ℃ without reduction, the aluminum alloy can not be melted into a melt after being heated, the aluminum alloy can not be decomposed until 1900 ℃, and the aluminum alloy has remarkable chemical resistance, can resist almost all inorganic acids and caustic soda solution with the concentration of less than 30 percent, and can resist corrosion of a plurality of organic acids; and is a high-performance electric insulating material. Therefore, in the etching process of the back plate structure 10, the first insulating layer 11, the second insulating layer 13 and the conductive layer 12 therebetween can be effectively prevented from being etched by the etching solution. Of course, in another embodiment, the material of the first insulating layer 11 and the second insulating layer 13 may be either boron nitride or silicon carbide, or may be silicon oxide.

In an embodiment of the present application, the first insulating layer 11 has been provided with a yielding hole 111, and the protruding structure 121 passes through the yielding hole 111 and is attached to the hole wall of the yielding hole 111. In this embodiment, the protruding structure protrudes out of the first insulating layer 11 through the yield hole 111, and the protruding structure 121 is attached to the hole wall of the yield hole 111, so that the hole wall of the yield hole 111 can limit and stabilize the protruding structure 121, thereby preventing the diaphragm 30 from having too large amplitude during operation and being damaged due to impact force generated by direct impact with the conductive layer 12.

In the embodiment of the present application, the protruding structure 121 is made of a conductive material. The material of the protruding structure 121 may be the same polysilicon material as the conductive layer 12, and the protruding structure 121 and the conductive layer 12 may be formed as an integral structure. Through setting up the material with protruding structure 121 to the conductor material, can avoid protruding structure 121 among the correlation technique to be insulating material, lead to protruding structure 121 and vibrating diaphragm 30 electric charge accumulation after contacting, produce the adhesion and cause the phenomenon that can not kick-back after the vibrating diaphragm 30 vibrates, conductor material can release electric charge, ensures that protruding structure 121 can not accumulate electric charge, the effectual static adhesion who reduces between protruding structure 121 and the vibrating diaphragm 30.

Further, the protruding structures 121 are disposed in a tapered shape, and the cross-sectional area gradually decreases in a direction away from the conductive layer 12. So set up for the terminal surface area that protruding structure 121 is close to vibrating diaphragm 30 one end is less than the terminal surface area of the other end, and when vibrating diaphragm 30 vibrates, the area that protruding structure 121 and vibrating diaphragm 30 contacted is less like this, thereby makes the adhesive force between the two also less, guarantees that vibrating diaphragm 30's resilience force can be greater than the adhesive force, and then can further reduce the risk that vibrating diaphragm 30 can not kick-back, increases the reliability of microphone.

Of course, in other embodiments, the shape of the protruding structure 121 may be a truncated cone shape, a semicircular shape, or the like.

In practical application, when the back plate structure 10 and the diaphragm 30 form a microphone, the electrically connected diaphragm 30 and the back plate structure 10 form a capacitor system of the microphone, and when the diaphragm 30 vibrates, the distance between the diaphragm 30 and the back plate structure 10 changes, which results in the change of the capacitance of the capacitor system, and then converts the sound wave signal into different electrical signals, thereby realizing the corresponding function of the microphone.

In order to enable the back plate structure 10 to form an effective capacitance area, in the embodiment of the present application, the conductive layer 12 includes a non-sensitive region 12a and a sensitive region 12b, a gap is formed between the sensitive region 12b and the non-sensitive region 12a, and the protruding structure 121 is disposed on the non-sensitive region 12 a. In this way, when the protrusion structure 121 is disposed in the non-sensitive region 12a, the protrusion structure 121 does not affect the capacitance of the spaced sensitive regions 12b, so as to prevent a short circuit caused by the contact between the protrusion structure 121 and the diaphragm 30.

Further, in the present application, the number of the sensitive areas 12b and the number of the non-sensitive areas 12a are both multiple, and the multiple sensitive areas 12b and the multiple non-sensitive areas 12a are sequentially and alternately arranged. In this embodiment, the number of the convex structures 121 is plural and is the same as the number of the non-sensitive regions 12 a. It can be understood that, by alternately arranging the plurality of sensitive regions 12b and the non-sensitive regions 12a, the conductive layer 12 can be ensured to have a sufficient effective capacitance area, so that when the diaphragm 30 vibrates, a corresponding capacitance change can be generated between the conductive layer 12 and the diaphragm 30, and the sensitive response performance is good.

The present invention further provides a MEMS sensor 100 (micro electro mechanical system microphone), the MEMS sensor 100 includes a substrate 20, a vibrating diaphragm 30 and a back plate structure 10, the vibrating diaphragm 30 is disposed on the surface of the substrate 20; the back plate structure 10 is disposed on a side of the diaphragm 30 back to the substrate 20, the first insulating layer 11 of the back plate structure 10 faces the diaphragm 30, a vibration gap 40 is formed between the first insulating layer and the diaphragm 30, and the protrusion structure 121 partially extends into the vibration gap 40. The specific structure of the back plate structure 10 refers to the above embodiments, and since the MEMS sensor 100 adopts all the technical solutions of all the above embodiments, at least all the beneficial effects brought by the technical solutions of the above embodiments are achieved, and no further description is given here.

The substrate 20 may be made of monocrystalline silicon, the substrate 20 is formed with a back cavity 21, the vibration gap 40 corresponds to the back cavity 21, and the diaphragm 30 may be made of polycrystalline silicon. In order to stably connect the back plate structure 10 and the diaphragm 30, a sacrificial layer 50 is disposed between the back plate structure 10 and the diaphragm 30, and the back plate structure 10 and the diaphragm 30 are respectively located on two sides of the sacrificial layer 50. The sacrificial layer 50 may be silicon oxide, and in an actual production process, the sacrificial layer 50 may be deposited on the diaphragm 30, and then the back plate structure 10 is deposited on the sacrificial layer 50, and the sacrificial layer 50 is etched to form the vibration gap 40 for the diaphragm 30 to vibrate.

As shown in fig. 1 to fig. 6, in an actual production process, after the sacrificial layer 50, the diaphragm 30 and the first insulating layer 11 are sequentially deposited on the substrate 20, the relief hole 111 may be formed by etching in the first insulating layer 11, then the conductive layer 12 is deposited, the protruding structure 121 provided on the conductive layer 12 passes through the relief hole 111, then the conductive layer 12 is separated into the sensitive region 12b and the non-sensitive region 12a, and then the second insulating layer 13 may be deposited on the conductive layer 12, and finally the substrate 20 and the sacrificial layer 50 are etched to form the back cavity 21 and the vibration gap 40.

When the microphone is used, the sound wave of the external sound reaches the diaphragm 30 through the back cavity 21, so as to drive the diaphragm 30 to vibrate, the electrically connected diaphragm 30 and the back plate structure 10 form a capacitance system of the MEMS sensor 100, when the diaphragm 30 vibrates, the capacitance of the capacitance system changes due to the change of the distance between the diaphragm 30 and the back plate structure 10, and then the sound wave signal is converted into different electrical signals, so as to realize the corresponding function of the microphone.

The utility model also provides an electronic equipment, wherein, this electronic equipment can be smart mobile phone, panel computer, TWS earphone or audiphone etc.. The electronic device includes a device body and the MEMS sensor 100 module disposed on the device body, and the specific structure of the MEMS sensor 100 module refers to the above embodiments, and since the electronic device adopts all the technical solutions of all the above embodiments, the electronic device at least has all the beneficial effects brought by the technical solutions of the above embodiments, and details are not repeated herein.

The above only is the preferred embodiment of the present invention, not limiting the scope of the present invention, all the equivalent structure changes made by the contents of the specification and the drawings under the inventive concept of the present invention, or the direct/indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A backplate structure, comprising:

a first insulating layer;

2. The backplate structure of claim 1, wherein the second insulating layer is the same or different thickness than the first insulating layer.

3. The backplate structure of claim 1, wherein the first insulating layer and/or the second insulating layer is a silicon nitride layer or a silicon oxide layer.

4. The back plate structure of claim 1, wherein the first insulating layer is formed with a relief hole, and the protruding structure passes through the relief hole and adheres to a wall of the relief hole.

5. The back plate structure of claim 4, wherein the raised structure is made of a conductive material.

6. The back plate structure of claim 4, wherein said raised structures are tapered and decrease in cross-sectional area in a direction away from said conductive layer.

7. The back plate structure of any one of claims 1-6, wherein the conductive layer comprises a non-sensitive region and a sensitive region, a gap is formed between the non-sensitive region and the sensitive region, and the protruding structure is disposed on the non-sensitive region.

8. The back plate structure of claim 7, wherein the number of the sensitive regions and the number of the non-sensitive regions are both plural, and the plural sensitive regions and the plural non-sensitive regions are alternately arranged in sequence.

9. A MEMS sensor, comprising;

a substrate;

the vibrating diaphragm is arranged on the surface of the substrate; and

the backplate structure of any one of claims 1-8, wherein the backplate structure is disposed on a side of the diaphragm facing away from the substrate, the first insulating layer is disposed facing the diaphragm and forms a vibration gap with the diaphragm, and the protrusion structure partially protrudes into the vibration gap.

10. An electronic device comprising a device body and a MEMS sensor disposed on the device body, the MEMS sensor being the MEMS sensor of claim 9.