CN214154838U

CN214154838U - Piezoelectric MEMS microphone

Info

Publication number: CN214154838U
Application number: CN202022828424.0U
Authority: CN
Inventors: 童贝; 石正雨; 沈宇; 段炼
Original assignee: Ruisheng Technology Nanjing Co Ltd
Current assignee: Ruisheng Technology Nanjing Co Ltd
Priority date: 2020-11-30
Filing date: 2020-11-30
Publication date: 2021-09-07
Anticipated expiration: 2030-11-30
Also published as: WO2022110442A1

Abstract

The utility model provides a piezoelectric MEMS microphone, which includes at least one piezoelectric MEMS unit. The piezoelectric MEMS unit includes: a base, including an annular peripheral wall enclosing a receiving cavity and a support structure arranged in the receiving cavity; a diaphragm; The structure is partially fixed to the support structure; the support structure includes a support portion spaced from the peripheral wall and a plurality of extension arms extending from the peripheral wall to the support portion; one end of the extension arm is connected to the support portion. The support part is connected, and the other end is connected with the peripheral wall to divide the receiving cavity into several cavities; the support part is formed with a through hole penetrating the support part along the vibration direction. The support structure of the utility model includes a support part spaced from the peripheral wall and several extension arms extending from the peripheral wall to the support part; the sound pressure of the air inlet is improved by arranging through holes in the support part.

Description

Piezoelectric MEMS microphone

[ technical field ] A method for producing a semiconductor device

The utility model relates to an acoustoelectric technology field especially relates to a piezoelectricity MEMS microphone.

[ background of the invention ]

The existing piezoelectric MEMS unit comprises a substrate, a support and a piezoelectric membrane, wherein the support comprises four support beam structures and support columns, the piezoelectric membrane comprises four cantilever beam membranes corresponding to the support beam structures, the piezoelectric membrane is fixed on the support column at the central position of the substrate, the tail ends of the cantilever beam membranes are warped under the action of sound pressure, so that the piezoelectric layer in the piezoelectric membrane is stressed to generate voltage output, and the piezoelectric membrane above the support column almost has no voltage output due to the large area of the support column; in addition, the sound pressure of the air inlet is affected when the patch is attached to the PCB.

[ Utility model ] content

An object of the utility model is to provide an improve air inlet acoustic pressure, and further promote MEMS microphone chip of sensitivity.

In order to achieve the above object, the present invention provides a piezoelectric MEMS microphone, including at least one piezoelectric MEMS element, the piezoelectric MEMS element includes: the substrate comprises an annular peripheral wall and a supporting structure, wherein the annular peripheral wall surrounds a containing cavity, and the supporting structure is arranged in the containing cavity; a diaphragm structure partially secured to the support structure; the supporting structure comprises a supporting part arranged at an interval with the peripheral wall and a plurality of extension arms extending from the peripheral wall to the supporting part; one end of the extension arm is connected with the supporting part, and the other end of the extension arm is connected with the peripheral wall so as to divide the accommodating cavity into a plurality of cavities; the supporting part is formed with a through hole penetrating the supporting part along a vibration direction.

Preferably, the base includes a first substrate, the accommodating cavity includes a first cavity formed in the first substrate, the peripheral wall includes a first peripheral wall enclosing the first cavity, the supporting portion includes a first supporting portion disposed in the first cavity and spaced from the first peripheral wall, the plurality of extension arms include a plurality of first extension arms extending from the first peripheral wall to the first supporting portion, and the through hole includes a first through hole formed along the vibration direction to penetrate through the first supporting portion.

Preferably, the substrate further includes an isolation layer disposed between the first substrate and the diaphragm structure, and a projection profile of the isolation layer along the vibration direction is the same as a projection profile of the first substrate along the vibration direction in shape.

Preferably, the diaphragm structure is structure as an organic whole, including fixed region and a plurality of movable part, fixed region include anchor portion and certainly a plurality of anchor arm that the edge radial extension of anchor portion formed, anchor portion is fixed in the supporting part, anchor arm is fixed in the extension arm, every movable part encircles anchor portion and with anchor arm interval sets up.

Preferably, the fixed region is disposed above the support structure, and the movable portion falls into the cavity along an axial orthographic projection of the base.

Preferably, the membrane structure includes a first electrode layer, a first piezoelectric layer and a second electrode layer stacked in sequence along the vibration direction, and the first electrode layer is disposed on one side of the membrane structure close to the support structure.

Preferably, the diaphragm structure further includes a second piezoelectric layer stacked on a side of the second electrode layer away from the first piezoelectric layer, and a third electrode layer stacked on the second piezoelectric layer.

Preferably, a plurality of the piezoelectric MEMS units are distributed in an array structure.

The utility model has the advantages that the utility model provides a piezoelectric MEMS microphone, the supporting structure of which comprises a supporting part arranged at an interval with the peripheral wall and a plurality of extension arms extending from the peripheral wall to the supporting part; the sound pressure of the air inlet is improved by arranging the through hole in the supporting part, and the sensitivity is further improved.

[ description of the drawings ]

FIG. 1 is a schematic structural diagram of a piezoelectric MEMS unit according to an embodiment of the present invention;

FIG. 2 is a front view of a piezoelectric MEMS unit of an embodiment of the present invention;

FIG. 3 is a perspective view of a piezoelectric MEMS unit of an embodiment of the present invention;

FIG. 4 is a bottom view of a piezoelectric MEMS element of an embodiment of the present invention;

FIG. 5 is a cross-sectional view taken along A-A of FIG. 3;

FIG. 6 is a schematic structural diagram of a substrate according to an embodiment of the present invention;

FIG. 7 is a perspective view of a substrate of an embodiment of the present invention;

FIG. 8 is a schematic structural diagram of a first substrate according to an embodiment of the invention;

FIG. 9 is a schematic structural diagram of an isolation layer according to an embodiment of the present invention;

FIG. 10 is a schematic structural diagram of a diaphragm structure according to an embodiment of the present invention;

FIG. 11 is a schematic structural diagram of a first electrode layer according to an embodiment of the invention;

fig. 12 is a schematic structural diagram of the first piezoelectric layer according to an embodiment of the invention.

[ detailed description ] embodiments

The present invention will be further described with reference to the accompanying drawings and embodiments.

It should be noted that all the directional indicators (such as upper, lower, left, right, front, back, inner, outer, top, bottom … …) in the embodiments of the present invention are only used to explain the relative position between the components in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is changed accordingly.

Referring to fig. 1 to 12, the utility model provides a piezoelectric MEMS microphone, piezoelectric MEMS microphone includes a plurality of piezoelectric MEMS unit 1 to a plurality of piezoelectric MEMS unit 1 is array structure and distributes, and in this embodiment, piezoelectric MEMS unit 1 is equipped with 4, and it is 2 a 2 array structure and distributes, is guaranteeing certain sensitivity or signal-to-noise ratio certainly, and piezoelectric MEMS unit 1 also can be 3 a 3 array structure and distribute, 4 a 4 array structure or more array structure.

Referring to fig. 1 to 5, a piezoelectric MEMS unit 1 includes a substrate 10 and a diaphragm structure 30, the square substrate 10 having a housing cavity 101; the diaphragm structure 30 is formed over the substrate 10.

Referring to fig. 6 and 7, the base 10 includes an annular peripheral wall 102 enclosing a housing chamber 101 and a support structure disposed in the housing chamber 101; the supporting structure includes a supporting portion 103 spaced from the peripheral wall 102 and a plurality of extending arms 104 extending from the peripheral wall 102 to the supporting portion 103, wherein the supporting portion 103 is disposed at a center position of the accommodating cavity 101. One end of the extension arm 104 is connected with the support portion 103, and the other end of the extension arm 104 is connected with the peripheral wall 102 so as to divide the accommodation cavity 101 into a plurality of cavities 105 arranged at intervals along the circumferential direction of the extension arm 104.

The substrate 10 includes a first substrate 11 and an isolation layer 12 disposed between the first substrate 11 and the diaphragm structure 30.

Referring to fig. 8, the first substrate 11 includes a first peripheral wall 112 enclosing a first cavity 111, a first supporting portion 113 disposed in the first cavity 111 and spaced apart from the first peripheral wall 112, and a first extension arm 114 extending from the first peripheral wall 112 to the first supporting portion 113, the first supporting portion 113 is disposed at a center position of the first cavity 111, and the first supporting portion 113 and the first extension arm 114 form a first supporting structure; one end of the first extension arm 114 is connected with the first support part 113, and the other end of the first extension arm 114 is connected with the first peripheral wall 112 so as to divide the first cavity 111 into a plurality of first sub-cavities 115 arranged at intervals along the circumferential direction of the first extension arm 114; wherein the first support part 113 is formed with a first through hole 116 penetrating the first support part 113 along the vibration direction, and the first through hole 116 is formed by etching.

Referring to fig. 9, the isolation layer 12 includes a second peripheral wall 122 enclosing a second cavity 121, a second supporting portion 123 disposed in the second cavity 121 and spaced apart from the second peripheral wall 122, and a second extension arm 124 extending from the second peripheral wall 122 to the second supporting portion 123, the second supporting portion 123 is disposed at a central position of the second cavity 121, and the second supporting portion 123 and the second extension arm 124 form a second supporting structure; one end of the second extension arm 124 is connected to the second support portion 123, and the other end of the second extension arm 124 is connected to the second peripheral wall 122 so as to divide the second cavity 121 into a plurality of second sub-cavities 125 arranged at intervals along the circumferential direction of the second extension arm 124; wherein the second supporting portion 123 is formed with a second through hole 126 penetrating the second supporting portion 123 along the vibration direction, and the second through hole 126 is formed by etching.

The first cavity 111 is communicated with the second cavity 121 to form a containing cavity 101, and the first peripheral wall 112 and the second peripheral wall 122 enclose to form an annular peripheral wall 102; the first supporting portion 113 and the second supporting portion 123 are overlapped to form a supporting portion 103 of the substrate, the first extension arm 114 and the second extension arm 124 form an extension arm 104 of the substrate, and the supporting portion 103 and the extension arm 104 form a supporting structure; the first subchamber 115 communicates with the second subchamber 125 to form the chamber 105. The extension arms 104 may be used to provide some support protection to the diaphragm structure 30 when the diaphragm structure 30 is greatly deformed, thereby preventing the diaphragm structure 30 from breaking.

The first through hole 116 and the second through hole 126 form the through hole 106 of the support portion 103, that is, the support portion 103 is a circular cylinder structure; the through hole 106 is arranged in the supporting part 103, so that the diaphragm structure 30 positioned above the through hole is stressed to generate voltage output, the overall sensitivity of the piezoelectric MEMS unit 1 is further improved, and meanwhile, the influence of sound pressure entering on the air inlet is reduced.

The diaphragm structure 30 is a structure, and includes fixed region 301 and a plurality of movable part 302, fixed region 301 includes anchor portion 303 and the anchor arm 304 that a plurality of interval set up, each anchor arm 304 certainly the edge radial extension of anchor portion 303 forms, anchor portion 303 is fixed in the supporting part 103, anchor arm 304 is fixed in extension arm 104, every movable part 302 encircle anchor portion 303, and with anchor arm 304 interval sets up.

The diaphragm structure 30 of the piezoelectric MEMS unit 1 is fixed on the supporting structure of the substrate 10 through the anchoring portion 303 and a plurality of anchoring arms 304 formed by radially extending from the edge of the anchoring portion 303, so that the contact area between the diaphragm structure 30 and the substrate 10 is increased, and the risk of peeling off the diaphragm structure 30 from the substrate 10 is effectively reduced.

In the present embodiment, an orthographic projection of the movable portion 302 along the axial direction of the substrate 10 falls into the cavity 105. Specifically, one movable portion 302 is suspended above each cavity 105, and the projection contour of each movable portion 302 in the direction perpendicular to the diaphragm structure 30 is located within the projection contour of the corresponding cavity 105 in the direction perpendicular to the diaphragm structure 30.

In the present embodiment, the projection profile of the inner sidewall of the annular peripheral wall 102 in the direction perpendicular to the diaphragm structure 30 may be a circle or a polygon, the number of the extension arms 104 may be set according to actual needs, the specific number is not limited, and as a preferred embodiment, the number of the extension arms 104 is four.

In the present embodiment, the projection profiles of the inner sidewall of the annular peripheral wall 102 and the outer sidewall of the support 103 in the substrate 10 in the direction perpendicular to the diaphragm structure 30 are both circular; the projection contour of the anchoring part 303 in the direction vertical to the diaphragm structure 30 is circular, and the projection contour of the anchoring arm 304 in the direction vertical to the diaphragm structure 30 is strip-shaped; the projection profile of the single movable portion 302 in the direction perpendicular to the diaphragm structure 30 is a fan-ring shape.

The membrane structure 30 is formed by stacking at least three layers of materials. Alternatively, the membrane structure 30 includes a first electrode layer 31, a first piezoelectric layer 32, and a second electrode layer 33, which are sequentially stacked in the vibration direction; alternatively, the membrane structure 30 includes a first electrode layer 31, a first piezoelectric layer 32, a second electrode layer 33, a second piezoelectric layer 34, and a third electrode layer 35, which are sequentially stacked in the vibration direction; alternatively, any other membrane structure formed by stacking an electrode layer and a piezoelectric layer is also applicable to the present invention. Wherein the first electrode layer 31 is disposed on a side of the membrane structure 30 close to the support structure.

Referring to fig. 11, the first electrode layer 31 includes a first electrode sheet 311 located in the movable portion 302, a second electrode sheet 312 located in the anchor portion 303, and a third electrode sheet 313 located in the anchor arm 304, and the first electrode sheet 311, the second electrode sheet 312, and the third electrode sheet 313 are disposed at intervals, and are integrally circular. The second electrode layer 33 and the third electrode layer 35 have the same structure as the first electrode layer 31.

The second electrode layer 33 includes a fourth electrode sheet located in the movable portion 302, a fifth electrode sheet located in the anchor portion 303, and a sixth electrode sheet located in the anchor arm 304, and the fourth, fifth, and sixth electrode sheets are disposed at intervals.

The third electrode layer 35 includes a seventh electrode piece located in the movable portion 302, an eighth electrode piece located in the anchor portion 303, and a ninth electrode piece located in the anchor arm 304, and the seventh electrode piece, the eighth electrode piece, and the ninth electrode piece are disposed at an interval from each other.

Referring to fig. 12, the first piezoelectric layer 32 includes a first movable portion 321 located at the movable portion 302 and a first fixed region 322 located at the fixed region 301, and the first movable portion 321 is connected to the first fixed region 322. The first piezoelectric layer 32 is integrally formed and has a circular structure as a whole, that is, the first movable portion 321 is connected to the first fixing area 322, so as to improve the reliability of the membrane structure 30. The second piezoelectric layer 34 is identical in structure to the first piezoelectric layer 32.

The second piezoelectric layer 34 includes a second movable portion located at the movable portion 302 and a second fixed region located at the fixed region 301, the second movable portion being connected to the second fixed region.

The above embodiments of the present invention are only described, and it should be noted that, for those skilled in the art, modifications can be made without departing from the inventive concept, but these all fall into the protection scope of the present invention.

Claims

1. A piezoelectric MEMS microphone comprising at least one piezoelectric MEMS element, the piezoelectric MEMS element comprising: the substrate comprises an annular peripheral wall and a supporting structure, wherein the annular peripheral wall surrounds a containing cavity, and the supporting structure is arranged in the containing cavity; a diaphragm structure partially secured to the support structure; the method is characterized in that: the supporting structure comprises a supporting part arranged at an interval with the peripheral wall and a plurality of extension arms extending from the peripheral wall to the supporting part; one end of the extension arm is connected with the supporting part, and the other end of the extension arm is connected with the peripheral wall so as to divide the accommodating cavity into a plurality of cavities; the supporting part is formed with a through hole penetrating the supporting part along a vibration direction.

2. A piezoelectric MEMS microphone as defined in claim 1, wherein: the basement includes first base plate, accept the chamber including form in the first cavity of first base plate, the perisporium is including enclosing into the first perisporium of first cavity, the supporting part including locate first cavity and with the first supporting part that first perisporium interval set up, it is a plurality of the extension arm includes certainly first perisporium extends to a plurality of first extension arms of first supporting part, the through-hole includes is formed with along the vibration direction and link up the first through-hole of first supporting part.

3. A piezoelectric MEMS microphone as defined in claim 2, wherein: the base further comprises an isolation layer arranged between the first substrate and the diaphragm structure, and the shape of the projection profile of the isolation layer along the vibration direction is the same as that of the projection profile of the first substrate along the vibration direction.

4. A piezoelectric MEMS microphone as defined in claim 1, wherein: the diaphragm structure is structure as an organic whole, including fixed region and a plurality of movable part, fixed region include anchor portion and certainly a plurality of anchor arm that the edge radial extension of anchor portion formed, anchor portion is fixed in the supporting part, the anchor arm is fixed in the extension arm, every the movable part encircles anchor portion and with the anchor arm interval sets up.

5. A piezoelectric MEMS microphone as claimed in claim 4, wherein: the fixed area is arranged above the supporting structure, and the movable part falls into the cavity along the axial orthographic projection of the substrate.

6. A piezoelectric MEMS microphone as claimed in claim 4, wherein: the diaphragm structure is including the first electrode layer, first piezoelectric layer and the second electrode layer that stack gradually along the vibration direction, first electrode layer set up in the diaphragm structure is close to one side of bearing structure.

7. A piezoelectric MEMS microphone as claimed in claim 6, wherein: the diaphragm structure further comprises a second piezoelectric layer and a third electrode layer, wherein the second piezoelectric layer is stacked on one side, far away from the first piezoelectric layer, of the second electrode layer, and the third electrode layer is stacked on the second piezoelectric layer.

8. Piezoelectric MEMS microphone according to claim 7, characterized in that: the piezoelectric MEMS units are distributed in an array structure.