CN110149582B - Preparation method of MEMS structure - Google Patents
Preparation method of MEMS structure Download PDFInfo
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- CN110149582B CN110149582B CN201910415714.1A CN201910415714A CN110149582B CN 110149582 B CN110149582 B CN 110149582B CN 201910415714 A CN201910415714 A CN 201910415714A CN 110149582 B CN110149582 B CN 110149582B
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- 239000002131 composite material Substances 0.000 claims abstract description 77
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- 238000004519 manufacturing process Methods 0.000 claims abstract description 20
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- 238000000034 method Methods 0.000 claims description 13
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- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 8
- 229910052451 lead zirconate titanate Inorganic materials 0.000 claims description 8
- 238000005192 partition Methods 0.000 claims description 6
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- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims description 4
- HFGPZNIAWCZYJU-UHFFFAOYSA-N lead zirconate titanate Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ti+4].[Zr+4].[Pb+2] HFGPZNIAWCZYJU-UHFFFAOYSA-N 0.000 claims description 4
- 239000012528 membrane Substances 0.000 claims description 4
- 229910021420 polycrystalline silicon Inorganic materials 0.000 claims description 4
- 239000011787 zinc oxide Substances 0.000 claims description 4
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 3
- 229910021421 monocrystalline silicon Inorganic materials 0.000 claims description 3
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 3
- 229910052814 silicon oxide Inorganic materials 0.000 claims description 3
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- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R17/00—Piezoelectric transducers; Electrostrictive transducers
- H04R17/02—Microphones
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R19/00—Electrostatic transducers
- H04R19/04—Microphones
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R31/00—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Manufacturing & Machinery (AREA)
- Micromachines (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
The present application provides a method of fabricating a MEMS (micro-electro-mechanical system) structure, comprising: etching a plurality of parallel first grooves on the front surface of a substrate, and depositing a piezoelectric composite vibration layer on the substrate, wherein the piezoelectric composite vibration layer formed on the bottom and the side walls of the first grooves forms a corrugated portion, wherein the corrugated portion is formed on the entire surface area of the piezoelectric composite vibration layer; etching the exposed substrate to form a second groove on the periphery of the piezoelectric composite vibration layer; etching the back surface of the substrate to form a cavity, a second groove being disposed adjacent to the periphery of the cavity, a piezoelectric composite vibration layer being formed right above the cavity, and a portion of the substrate located between the second groove and the cavity supporting the piezoelectric composite vibration layer. The manufactured MEMS structure improves the displacement and deformation of the piezoelectric composite vibration layer under the action of sound pressure, reduces the residual stress and further improves the sensitivity of the MEMS structure.
Description
Technical Field
The present application relates to the field of semiconductor technology, and in particular, to a method for fabricating a structure of a MEMS (micro electro Mechanical Systems, which is abbreviated as micro electro Mechanical Systems).
Background
MEMS microphones (microphones) mainly include both capacitive type and piezoelectric type. The MEMS piezoelectric microphone is prepared by utilizing a micro-electro-mechanical system technology and a piezoelectric film technology, and has small size, small volume and good consistency due to the adoption of semiconductor planar technology, bulk silicon processing technology and other technologies. Meanwhile, compared with a capacitor microphone, the MEMS piezoelectric microphone also has the advantages of no bias voltage, large working temperature range, dust prevention, water prevention and the like, but the sensitivity is low, so that the development of the MEMS piezoelectric microphone is restricted. Among them, the large residual stress of the diaphragm is an important cause of low sensitivity thereof.
Aiming at the problems of reducing the residual stress of the piezoelectric MEMS structure and improving the deformation of the vibrating membrane in the related technology, no effective solution is provided at present.
Disclosure of Invention
Aiming at the problem of large residual stress in the related technology, the application provides a preparation method of an MEMS structure, which can effectively reduce the residual stress.
The technical scheme of the application is realized as follows:
according to an aspect of the present application, there is provided a method of fabricating a MEMS (micro electro mechanical system) structure, comprising:
etching a plurality of parallel first grooves on the front surface of a substrate, and depositing a piezoelectric composite vibration layer on the substrate, wherein the piezoelectric composite vibration layer formed on the bottom and the side walls of the first grooves forms a corrugated portion, wherein the corrugated portion is formed on the entire surface area of the piezoelectric composite vibration layer;
etching to form a second groove on the exposed substrate at the periphery of the piezoelectric composite vibration layer;
etching the back surface of the substrate to form a cavity, the second groove being disposed adjacent to the periphery of the cavity, the piezoelectric composite vibration layer being formed right above the cavity, and the substrate at a portion between the second groove and the cavity supporting the piezoelectric composite vibration layer.
Wherein the method of forming the piezoelectric composite vibration layer includes:
depositing a support material on the substrate with the first groove to form a vibration support layer;
depositing a first electrode material on the vibrating support layer and patterning the first electrode material to form a first electrode layer;
depositing a piezoelectric material over the first electrode layer and patterning the piezoelectric material to form a first piezoelectric layer;
depositing a second electrode material over the first piezoelectric layer, and patterning the second electrode material to form a second electrode layer.
Wherein the vibration support layer, the first electrode layer, the first piezoelectric layer, and the second electrode layer formed on the bottom and the side wall of the first groove constitute the corrugated portion.
Wherein the first electrode layer, the first piezoelectric layer, and the second electrode layer formed on the bottom and the side walls of the first groove are etched away, and the vibration support layer remaining on the bottom and the side walls of the first groove constitutes the corrugated portion.
Wherein a central plane of one of the first grooves passes through a central point of the piezoelectric composite vibration layer and divides the piezoelectric composite vibration layer into two regions.
Wherein the plurality of parallel first grooves are arranged at equal intervals.
Wherein the method of forming the piezoelectric composite vibration layer further comprises:
etching the substrate to form a plurality of parallel third grooves, wherein the central plane of one third groove passes through the central point of the piezoelectric composite vibration layer, and the first groove and the third groove divide the piezoelectric composite vibration layer into four regions;
and depositing and forming the piezoelectric composite vibration layer on the substrate with the first groove and the third groove.
The method for manufacturing the MEMS structure further comprises the steps of etching the first electrode layer and the second electrode layer respectively to form a fourth groove, separating the first electrode layer and the second electrode layer into at least two partitions by the fourth groove, forming electrode layer pairs by the partitions of the first electrode layer and the second electrode layer which correspond to each other, and then sequentially connecting the electrode pairs in series.
The vibration supporting layer comprises a single-layer or multi-layer composite membrane structure formed by silicon nitride, silicon oxide, monocrystalline silicon and polycrystalline silicon.
The vibration support layer comprises a piezoelectric material layer and electrode material layers positioned above and below the piezoelectric material layer, wherein the piezoelectric material layer comprises one or more layers of zinc oxide, aluminum nitride, an organic piezoelectric film, lead zirconate titanate (PZT) or perovskite type piezoelectric film.
Wherein the method of manufacturing the MEMS structure further includes etching a plurality of through holes penetrating the piezoelectric composite vibration layer, wherein the plurality of through holes are closer to a center of the piezoelectric composite vibration layer than the corrugated portion.
Wherein etching forms the plurality of through holes that continuously penetrate the vibration support layer, the first electrode layer, the first piezoelectric layer, and the second electrode layer.
Wherein a fifth groove extending from the upper surface of the second electrode layer to the lower surface of the first electrode layer is formed by etching, and the plurality of through holes are located in the fifth groove and penetrate through the vibration support layer only.
And the dividing straight line formed by connecting the through holes passes through the center of the piezoelectric composite vibration layer, the central plane of at least one first groove passes through the central point of the piezoelectric composite vibration layer, and the central plane of the first groove is coplanar with the dividing straight line.
In the MEMS structure manufactured by the method, the piezoelectric composite vibration layer is formed right above the cavity and in the middle of the second groove, so that part of the substrate material between the second groove and the cavity supports the piezoelectric composite vibration layer, and the piezoelectric composite vibration layer is converted from a solid support state to a similar simple support state, thereby improving the displacement and deformation of the piezoelectric composite vibration layer under the action of sound pressure, reducing the residual stress and further improving the sensitivity of the MEMS structure.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Various aspects of the present application may be better understood from the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale and are used for illustration purposes only. In fact, the dimensions of the various elements may be arbitrarily increased or decreased for clarity of discussion.
FIG. 1 is a schematic perspective view of a MEMS structure according to some embodiments of the present application;
FIG. 2 is a cross-sectional perspective view of the MEMS structure of FIG. 1 taken along line A-A;
FIG. 3 is an enlarged schematic view of the corrugated portion shown in FIG. 2;
fig. 4, 5 and 7 are cross-sectional views of intermediate stages in forming a MEMS structure according to some embodiments of the present application;
FIG. 6 is a schematic perspective view of a MEMS structure according to other embodiments of the present application.
Detailed Description
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, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments that can be derived from the embodiments given herein by a person of ordinary skill in the art are intended to be within the scope of the present disclosure.
The following disclosure provides many different embodiments, or examples, for implementing different features of the application. Specific examples of components and arrangements are described below to simplify the present application. These are, of course, merely examples and are not intended to be limiting. For example, the dimensions of the elements are not limited to the disclosed ranges or values, but may depend on the process conditions and/or desired properties of the device. Further, in the following description, forming a first feature over or on a second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. Various components may be arbitrarily drawn in different sizes for simplicity and clarity.
Furthermore, for ease of description, spatially relative terms such as "below", "lower", "above", "upper", and the like may be used herein to describe one element or component's relationship to another (or other) element or component as illustrated in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Additionally, the term "made of can mean" including "or" consisting of.
According to the embodiment of the application, the MEMS structure 100 is provided, which can reduce low frequency sound leakage and improve the stability of the microphone operation and preparation while reducing the residual stress and improving the strain of the piezoelectric composite vibration layer 20.
Referring to fig. 1 and 2, fig. 2 is a sectional perspective view of fig. 1 taken along line a-a. Fig. 1 and 2 illustrate a MEMS structure according to one embodiment of the present application. The MEMS structure will be described in detail below.
The MEMS structure comprises a substrate 10, wherein the substrate 10 has a cavity 11 and a first recess 12 arranged adjacently, the first recess 12 being formed at the periphery of the cavity 11. The substrate 10 comprises silicon or any suitable silicon-based compound or derivative (e.g., silicon wafer, SOI, polysilicon on SiO 2/Si).
The piezoelectric composite vibration layer 20 is formed directly above the cavity 11 and in the middle of the first groove 12. And the piezoelectric composite vibration layer 20 has a corrugated portion 26. Referring to fig. 3, fig. 3 is an enlarged schematic view of the corrugated portion 26. The corrugated portion 26 will be described in detail below.
In the MEMS structure of the above embodiment, the piezoelectric composite vibration layer 20 is formed directly above the cavity 11 and located in the middle of the first groove 12, so that a part of the substrate material located between the first groove 12 and the cavity 11 supports the piezoelectric composite vibration layer 20, and further the piezoelectric composite vibration layer 20 is changed from a clamped state to a similar simply-supported state, and therefore, displacement and deformation of the piezoelectric composite vibration layer 20 under the action of sound pressure are improved, and further, the sensitivity of the MEMS structure is improved. Moreover, the corrugated portion 26 of the piezoelectric composite vibrating layer 20 can make the "taut" vibrating membrane "soft, so that each area of the piezoelectric composite vibrating layer 20 obtains larger displacement and deformation under the same sound pressure, thereby further improving the sensitivity of the MEMS structure.
The process for forming the MEMS structure will be described in detail below. For clarity of illustration, fig. 4, 5 and 7 below are not drawn to the scale shown in fig. 1, but rather the dimensions of the first recess 12 are relatively increased for ease of understanding and illustration.
Referring collectively to fig. 4, in some embodiments, the substrate 10 is etched to form a plurality of parallel second grooves 13 and another plurality of parallel third grooves 14. The central plane of one of the second grooves 13 passes through the central point of the substrate 10, and the second groove 13 divides the substrate 10 into two regions. And a central plane of one of the third grooves 14 passes through a central point of the substrate 10, and the second groove 13 and the third groove 14 divide the substrate 10 into four regions. In some embodiments, the plurality of parallel second grooves 13 are arranged at equal intervals. In some embodiments, the plurality of parallel third grooves 14 are disposed at equal intervals.
Next, see fig. 5. A vibration support layer 24, a first electrode layer 21, a first piezoelectric layer 22, and a second electrode layer 23 are sequentially deposited and patterned on the substrate 10 having the second and third grooves 13 and 14. Here, the vibration support layer 24, the first electrode layer 21, the first piezoelectric layer 22, and the second electrode layer 23 constitute the piezoelectric composite vibration layer 20. It is to be noted that the piezoelectric composite vibration layer 20 includes portions formed at the bottom and the side walls of the second groove 13 and the third groove 14, i.e., the corrugated portion 26 shown in fig. 3.
Since the piezoelectric composite vibration layer 20 has the portions, i.e., the corrugated portions 26, formed on the bottom and the side walls of the second groove 13 and the third groove 14, the corrugated portions 26 divide the piezoelectric composite vibration layer 20 into four regions, and the edges of each region are connected by the corrugated portions 26, so that the stress of the entire piezoelectric composite vibration layer 20 is released, and at the same time, the effect of the cantilever-like structure is achieved, so that the "tight" piezoelectric composite vibration layer 20 becomes "soft". Thus, under the same sound pressure, each area of the piezoelectric composite vibration layer 20 obtains larger displacement and strain, and the effect of improving the sensitivity of the MEMS structure is also achieved.
In further embodiments, the first electrode layer 21, the first piezoelectric layer 22 and the third electrode layer 23 in the second recess 13 and the third recess 14 may be etched away. The vibration support layer 24 is retained only in the second and third recesses 13, 14. In this case, the corrugated portion 26 includes only the material of the vibration support layer 24.
In some embodiments, the substrate 10 may have only the second recess 13, and not the third recess 14.
In some embodiments, the vibration support layer 24 comprises silicon nitride (Si)3N4) Silicon oxide, monocrystalline silicon, polycrystalline silicon, or other suitable support material.
In some embodiments, the vibration support layer 24 may include a layer of piezoelectric material and layers of electrode material on top of and below the layer of piezoelectric material. Wherein the piezoelectric material layer comprises one or more layers of zinc oxide, aluminum nitride, an organic piezoelectric film, lead zirconate titanate (PZT), a perovskite-type piezoelectric film, or other suitable materials. In this case, the vibration support layer 24 functions as both support and piezoelectric.
In some embodiments, the first piezoelectric layer 22 may convert the applied pressure into a voltage, and the first electrode layer 21 and the second electrode layer 23 may transmit the generated voltage to other integrated circuit devices. In some embodiments, the first piezoelectric layer 22 comprises zinc oxide, aluminum nitride, an organic piezoelectric film, lead zirconate titanate (PZT), a perovskite-type piezoelectric film, or other suitable material. The first electrode layer 21 and the second electrode layer 23 include aluminum, gold, platinum, molybdenum, titanium, chromium, and a composite film composed of them or other suitable materials.
Next, referring to fig. 6, in some embodiments where the second and third grooves 13 and 14 are not formed in the middle portion of the substrate 10, a plurality of through holes 25 continuously penetrating the vibration support layer 24, the first electrode layer 21, the first piezoelectric layer 22, and the second electrode layer 23 are etched in the middle portion of the substrate 10. Alternatively, a fifth groove (not shown in the figure) extending from the upper surface of the second electrode layer 23 to the lower surface of the first electrode layer 21 may be etched in the middle portion of the substrate 10, and the plurality of through holes 25 may be located in the fifth groove, in which case the plurality of through holes 25 only penetrate the vibration support layer 24. In other words, the plurality of through holes 25 in the embodiment of the present application may penetrate four layers, i.e., the vibration support layer 24, the first electrode layer 21, the first piezoelectric layer 22, and the second electrode layer 23, in succession, or may penetrate only one vibration support layer 24.
The plurality of through holes 25 are closer to the center of the piezoelectric composite vibration layer 20 than the corrugated portion 26. In some embodiments, the straight dividing line connecting the plurality of through holes 25 passes through the center point of the piezoelectric composite vibration layer 20. Wherein the central plane of at least one second groove 13 passes through the central point of the piezoelectric composite vibration layer 20, and the central plane of the second groove 13 is coplanar with the dividing straight line. The plurality of through holes 25 release the stress of the middle portion of the piezoelectric composite vibration layer 20, and achieve the effect of a cantilever-like structure. In some embodiments, the step of forming the plurality of vias 25 may be omitted or skipped.
Next, in some embodiments, the vibration support layer 24, the first electrode layer 21, the first piezoelectric layer 22, and the second electrode layer 23 are etched, thereby exposing portions of the substrate 10.
Referring to fig. 7, in some embodiments, a first recess 12 extending into the substrate 10 is etched and formed on the exposed substrate 10 at the periphery of the first electrode layer 21, the first piezoelectric layer 22, and the second electrode layer 23. In still other embodiments, the outer peripheral portion of the vibration support layer 24 may be exposed by etching the first electrode layer 21, the first piezoelectric layer 22, and the second electrode layer 23. A groove extending into the substrate 10 is then etched in the periphery of the vibration support layer 24, the portion of the groove within the substrate 10 constituting the first groove 12. The portions of the substrate 10 and the portion of the vibration support layer 24 outside the first recess 12 are then removed, resulting in the first recess 12 shown in fig. 7.
In some embodiments, the back surface of the substrate 10 is etched to form a cavity 11, and the first groove 12 is disposed at the periphery of the cavity 11. And, the vibration support layer 24, the first electrode layer 21, the first piezoelectric layer 22, and the second electrode layer 23 are formed right above the cavity 11. Specifically, the method comprises the following steps: an insulating material (not shown) and a photoresist are sequentially deposited on the back surface of the substrate 10 by a standard photolithography process, the photoresist is patterned to form a mask layer, and the exposed insulating material and the substrate 10 are etched to form the cavity 11. The insulating material of the backside of the substrate 10 is then removed. In fig. 7, the portion of the substrate 10 located between the second recess 13 and the cavity 11 is small in size, so that the piezoelectric composite vibration layer 20 can be in contact and supported with the substrate 10 only in a small area, thereby improving displacement and deformation of the piezoelectric composite vibration layer 20 under the sound pressure.
Based on the above embodiment, referring to fig. 3, after the cavity 11 is formed, the piezoelectric composite vibration layer 20 is formed into the corrugated portion 26 as shown in fig. 3. The piezoelectric composite vibration layer 20 is formed right above the cavity 11 and is located in the middle of the first groove 12, so that part of the substrate material located between the first groove 12 and the cavity 11 supports the piezoelectric composite vibration layer 20, and further the piezoelectric composite vibration layer 20 is changed from a solid support state to a similar simple support state, and therefore, the displacement and the deformation of the piezoelectric composite vibration layer 20 under the action of sound pressure are improved, and the sensitivity of the MEMS structure is further improved.
Further, the method for manufacturing the MEMS structure further includes etching the first electrode layer 21 and the second electrode layer 23 to form a fourth groove (not shown in the figure), where the fourth groove separates the first electrode layer 21 and the second electrode layer 23 into at least two partitions, and the partitions of the first electrode layer 21 and the second electrode layer 23 corresponding to each other form an electrode pair, and then sequentially connect the electrode pairs in series, so that the piezoelectric thin film transducers of the cantilever structures are electrically connected in series, thereby further improving the sensitivity of the MEMS structure.
In summary, according to the above technical solution of the present application, by using the method for manufacturing the MEMS structure, the residual stress of the piezoelectric composite vibration layer 20 is reduced, and the deformation of the piezoelectric composite vibration layer 20 under the action of the sound pressure is improved, so that the sensitivity of the MEMS structure is improved.
The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.
Claims (14)
1. A method of fabricating a MEMS structure, comprising:
etching a plurality of parallel first grooves on a front surface of a substrate, depositing a piezoelectric composite vibration layer on the substrate, wherein the piezoelectric composite vibration layer formed on a bottom and a side wall of the first grooves constitutes a corrugated portion, wherein the corrugated portion is formed over an entire surface area of the piezoelectric composite vibration layer, one of the first grooves is in a radial direction of the piezoelectric composite vibration layer, and divides the piezoelectric composite vibration layer into at least two regions;
etching the back surface of the substrate to form a cavity, wherein the piezoelectric composite vibration layer is formed right above the cavity.
2. The method of fabricating a MEMS structure of claim 1, wherein the method of forming the piezoelectric composite vibration layer comprises:
depositing a support material on the substrate with the first groove to form a vibration support layer;
depositing a first electrode material on the vibrating support layer and patterning the first electrode material to form a first electrode layer;
depositing a piezoelectric material over the first electrode layer and patterning the piezoelectric material to form a first piezoelectric layer;
depositing a second electrode material over the first piezoelectric layer, and patterning the second electrode material to form a second electrode layer.
3. The method of manufacturing a MEMS structure according to claim 2, wherein the vibration support layer, the first electrode layer, the first piezoelectric layer, and the second electrode layer formed on the bottom and the side wall of the first groove constitute the corrugated portion.
4. The method of manufacturing a MEMS structure according to claim 2, wherein the first electrode layer, the first piezoelectric layer, and the second electrode layer formed on the bottom and the side wall of the first groove are etched away, and the vibration support layer remaining on the bottom and the side wall of the first groove constitutes the corrugated portion.
5. A method of fabricating a MEMS structure according to claim 1 wherein a plurality of parallel first grooves are provided at equal intervals.
6. The method of fabricating a MEMS structure of claim 1, wherein the method of forming the piezoelectric composite vibration layer further comprises:
etching the substrate to form a plurality of parallel third grooves, wherein one of the third grooves is in the radial direction of the piezoelectric composite vibration layer, and the first groove and the third groove divide the piezoelectric composite vibration layer into at least four areas;
and depositing and forming the piezoelectric composite vibration layer on the substrate with the first groove and the third groove.
7. The method of manufacturing a MEMS structure according to claim 2, further comprising etching the first electrode layer and the second electrode layer respectively to form a fourth groove, the fourth groove separating the first electrode layer and the second electrode layer into at least two partitions, the partitions of the first electrode layer and the second electrode layer corresponding to each other constituting an electrode layer pair, and then sequentially connecting a plurality of the electrode layer pairs in series.
8. The method of fabricating a MEMS structure of claim 2, wherein the vibrating support layer comprises a single or multi-layer composite membrane structure of silicon nitride, silicon oxide, single crystal silicon, polysilicon.
9. The method of fabricating a MEMS structure of claim 2, wherein the vibration support layer comprises a piezoelectric material layer and electrode material layers on and under the piezoelectric material layer, wherein the piezoelectric material layer comprises one or more of zinc oxide, aluminum nitride, an organic piezoelectric film, lead zirconate titanate (PZT), or a perovskite-type piezoelectric film.
10. The method of fabricating a MEMS structure of claim 2, further comprising etching a plurality of through holes through the piezoelectric composite vibration layer, wherein the plurality of through holes are closer to a center of the piezoelectric composite vibration layer than the corrugated portion.
11. The method of fabricating a MEMS structure of claim 10, wherein etching forms the plurality of vias continuously through the vibration support layer, the first electrode layer, the first piezoelectric layer, and the second electrode layer.
12. The method of fabricating a MEMS structure of claim 10 wherein etching forms a fifth recess extending from the upper surface of the second electrode layer to the lower surface of the first electrode layer, and the plurality of vias are located within the fifth recess, the plurality of vias extending only through the vibration support layer.
13. The method of manufacturing a MEMS structure according to claim 10, wherein a dividing line connecting the plurality of through holes passes through a center of the piezoelectric composite vibration layer, wherein a central plane of at least one of the first grooves passes through a center point of the piezoelectric composite vibration layer, and the central plane of the first groove is coplanar with the dividing line.
14. The method of manufacturing a MEMS structure according to claim 1, wherein a second groove is etched on the exposed substrate at a periphery of the piezoelectric composite vibration layer, the second groove is disposed adjacent to a periphery of the cavity, and a portion of the substrate between the second groove and the cavity supports the piezoelectric composite vibration layer.
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| CN112584283B (en) * | 2020-11-30 | 2022-02-18 | 瑞声新能源发展(常州)有限公司科教城分公司 | Piezoelectric MEMS microphone, array thereof and preparation method thereof |
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| CN115567024B (en) * | 2022-08-26 | 2023-06-06 | 见闻录(浙江)半导体有限公司 | Bulk acoustic wave resonator, manufacturing method thereof, filter and electronic equipment |
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