CN116605834A - MEMS sensor and preparation method thereof - Google Patents

MEMS sensor and preparation method thereof Download PDF

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Publication number
CN116605834A
CN116605834A CN202310596728.4A CN202310596728A CN116605834A CN 116605834 A CN116605834 A CN 116605834A CN 202310596728 A CN202310596728 A CN 202310596728A CN 116605834 A CN116605834 A CN 116605834A
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China
Prior art keywords
wafer layer
layer
wafer
conductive
electrode
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CN202310596728.4A
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Chinese (zh)
Inventor
裘进
王鹏辉
杨云春
王飞飞
张向超
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Silex Microsystems Technology Beijing Co ltd
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Silex Microsystems Technology Beijing Co ltd
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Priority to CN202310596728.4A priority Critical patent/CN116605834A/en
Publication of CN116605834A publication Critical patent/CN116605834A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
    • B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
    • B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B3/00—Devices comprising flexible or deformable elements, e.g. comprising elastic tongues or membranes
    • B81B3/0018—Structures acting upon the moving or flexible element for transforming energy into mechanical movement or vice versa, i.e. actuators, sensors, generators
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
    • B81B7/0032—Packages or encapsulation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
    • B81B7/02—Microstructural systems; Auxiliary parts of microstructural devices or systems containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
    • B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
    • B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
    • B81C1/00023—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems without movable or flexible elements
    • B81C1/00039—Anchors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
    • B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
    • B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
    • B81C1/00134—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems comprising flexible or deformable structures
    • B81C1/00166—Electrodes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
    • B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
    • B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
    • B81C1/00261—Processes for packaging MEMS devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B2201/00—Specific applications of microelectromechanical systems
    • B81B2201/02—Sensors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
    • B81C2203/00—Forming microstructural systems
    • B81C2203/01—Packaging MEMS
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Abstract

The application discloses a preparation method of an MEMS sensor and the sensor, and belongs to the technical field of sensors. The method comprises the following steps: providing a third wafer layer, wherein the third wafer layer is provided with at least one second functional electrode perpendicular to the third wafer layer, and one surface of the third wafer layer for bonding with the second wafer layer is provided with a first groove; forming at least one raised support structure within the first recess; a second insulating layer and a third insulating layer are formed on the third wafer layer and on one side of the at least one bump support structure for bonding with the second wafer layer, respectively. The formation of raised support structures within the first recess may serve to strengthen the structural strength between the second wafer layer and the third wafer layer. And at least one second functional electrode is formed on the third wafer layer, so that the space of the third wafer layer can be fully utilized, and the requirement of the MEMS sensor on the functional electrode is met.

Description

MEMS sensor and preparation method thereof
Technical Field
The application relates to the technical field of sensors, in particular to a preparation method of an MEMS sensor and the sensor.
Background
The MEMS (micro electro mechanical systems) sensor is a micro-electromechanical system, has the characteristics of high precision, high sensitivity, low power consumption and the like, and is widely applied to the fields of mobile equipment, intelligent home, automobiles, medical treatment, industry and the like. MEMS sensors can be classified into gyroscopes, accelerometers, pressure sensors, temperature sensors, etc. according to the physical quantity measured and the field of application.
In the related art, there is provided a MEMS sensor including a first wafer layer, a second wafer layer, and a third wafer layer bonded in order, the first wafer layer being a fixed electrode wafer layer, and a plurality of functional electrodes being formed on the first wafer layer. The second wafer layer is a mass wafer layer and comprises a mass block, the mass block is hung on the first wafer layer through an anchor point structure, and the mass block can vibrate in the groove along the direction parallel to or perpendicular to the second wafer layer around the anchor point structure. The third wafer layer is a sealing wafer layer, and a groove is formed in one surface of the third wafer layer, which is bonded with the second wafer layer, so as to provide a vibration space for vibration of the mass block.
However, forming grooves on the side of the third wafer layer bonded to the second wafer layer may result in poor structural strength between the third wafer layer and the second wafer layer. Meanwhile, in the MEMS sensor structure, each functional electrode is located on the first wafer layer, and the space of the first wafer layer is limited, so that the setting requirement of the MEMS sensor on the functional electrode cannot be met.
Disclosure of Invention
The present application has been made in view of the above-mentioned problems, and has as its object to provide a method for manufacturing a MEMS sensor and a sensor which overcome or at least partially solve the above-mentioned problems, and which can serve to enhance the structural strength between the second wafer layer and the third wafer layer by providing a bump support structure in a recess of the third wafer layer. Meanwhile, an insulating layer is arranged between the second wafer layer and the third wafer layer, a second functional electrode is formed on the third wafer layer, the third wafer layer is fully utilized, and the requirement of the MEMS sensor on the functional electrode can be further met.
In one aspect, a method for preparing a MEMS sensor is provided, the method comprising:
providing a first wafer layer, wherein a plurality of first functional electrodes perpendicular to the first wafer layer are arranged on the first wafer layer, and the first functional electrodes are mutually insulated;
providing a second wafer layer, wherein the second wafer layer comprises at least one mass block;
providing a third wafer layer, wherein the third wafer layer is provided with at least one second functional electrode perpendicular to the third wafer layer, and one surface of the third wafer layer, which is used for bonding with the second wafer layer, is provided with a first groove;
forming at least one raised support structure within the first recess;
forming a second insulating layer on one surface of the third wafer layer for bonding with the second wafer layer;
forming a third insulating layer on a surface of the at least one raised support structure for bonding with the second wafer layer;
and sequentially bonding the first wafer layer, the second wafer layer and the third wafer layer, and enabling each mass block to be suspended on the first wafer layer through an anchor point structure, wherein the mass blocks can vibrate around the anchor point structure along a direction parallel to or perpendicular to the second wafer layer.
Optionally, before the first wafer layer, the second wafer layer and the third wafer layer are bonded in sequence, the preparation method further includes:
forming an isolation groove perpendicular to the first wafer layer on the first wafer layer, and dividing the first wafer layer into an inner wafer layer and an outer wafer layer which are isolated from each other in an insulating manner, wherein the plurality of first functional electrodes are positioned on the inner wafer layer;
and forming a second conductive hole on the second insulating layer, and forming a conductive material in the second conductive hole.
Optionally, after the first wafer layer, the second wafer layer and the third wafer layer are bonded in sequence, the preparation method further includes:
forming a first insulating layer on a side of the first wafer layer away from the second wafer layer;
forming a plurality of first conductive holes in the region of the first insulating layer corresponding to the inner wafer layer, wherein the first conductive holes are in one-to-one correspondence with the first functional electrodes;
and forming electrode pads for electrically connecting with the corresponding first functional electrodes in the first conductive holes.
Optionally, the preparation method further comprises:
forming a third conductive hole in a region of the first insulating layer corresponding to the outer wafer layer;
and forming an electrode pad in the third conductive hole, wherein the electrode pad is used for being electrically connected with the outer wafer layer.
Optionally, the preparation method further comprises:
and forming a conductive layer on one surface of the third wafer layer, which is far away from the second wafer layer, wherein the conductive layer is electrically connected with the at least one second functional electrode.
Optionally, the preparation method further comprises:
and forming a second groove on one surface of the second wafer layer bonded with the first wafer layer.
In a second aspect, a MEMS sensor is provided, where the MEMS sensor is prepared by using the preparation method of the first aspect, and the MEMS sensor includes a first wafer layer, a second wafer layer, and a third wafer layer that are sequentially bonded;
the first wafer layer is provided with a plurality of first functional electrodes perpendicular to the first wafer layer, and the first functional electrodes are mutually insulated;
the second wafer layer comprises at least one mass block, each mass block is suspended on the first wafer layer through an anchor point structure, and the mass blocks can vibrate around the anchor point structure along a direction parallel to or perpendicular to the second wafer layer;
a first groove is formed in one surface of the third wafer layer, which is bonded with the second wafer layer, at least one protruding supporting structure is arranged in the first groove, and at least one second functional electrode perpendicular to the third wafer layer is arranged on the third wafer layer;
the MEMS sensor further includes a second insulating layer between the third wafer layer and the second wafer layer, and a third insulating layer between the raised support structure and the second wafer layer.
Optionally, the first wafer layer includes an inner wafer layer and an outer wafer layer located outside the inner wafer layer, an isolation groove perpendicular to the first wafer layer is formed between the inner wafer layer and the outer wafer layer, the inner wafer layer and the outer wafer layer are isolated from each other by insulation through the isolation groove, and the plurality of first functional electrodes are located on the inner wafer layer;
and a second conductive hole is formed in the second insulator, a conductive material is arranged in the second conductive hole, and the outer wafer layer and the second wafer layer are electrically connected with the at least one second functional electrode on the third wafer layer through the conductive material in the second conductive hole.
Optionally, the MEMS sensor further comprises a first insulating layer on a side of the first wafer layer remote from the second wafer layer;
a plurality of first conductive holes corresponding to the first functional electrodes one by one are formed in the first insulating layer, and electrode pads used for being electrically connected with the corresponding first functional electrodes are arranged in the first conductive holes.
Optionally, a third conductive hole corresponding to the outer wafer layer is formed in the first insulating layer, and an electrode pad for electrically connecting with the outer wafer layer is arranged in the third conductive hole.
The technical scheme provided by the embodiment of the application has at least the following technical effects or advantages:
according to the manufacturing method of the MEMS sensor and the sensor provided by the embodiment of the application, at least one raised supporting structure is arranged in the first groove of the third wafer layer, and can play a supporting role, so that the structural strength between the third wafer layer and the second wafer layer is enhanced. Meanwhile, by forming a second insulating layer between the third wafer layer and the second wafer layer and forming a third insulating layer between the bump support structure and the second wafer layer, electrical insulation of the third wafer layer from the second wafer layer is achieved. At this time, the space of the third wafer layer can be utilized to set at least one second functional electrode on the third wafer layer, so as to further meet the setting requirement of the MEMS sensor on the functional electrode.
The foregoing description is only an overview of the present application, and is intended to be implemented in accordance with the teachings of the present application in order that the same may be more clearly understood and to make the same and other objects, features and advantages of the present application more readily apparent.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the application. Also, like reference numerals are used to designate like parts throughout the figures.
In the drawings:
FIG. 1 is a flowchart of a method for manufacturing a MEMS sensor according to an embodiment of the present application;
FIG. 2 is a cross-sectional view of a MEMS sensor provided in an embodiment of the present application;
fig. 3 is a schematic diagram of a part of a structure of a MEMS sensor according to an embodiment of the present application.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present application more apparent, the embodiments of the present application will be described in further detail with reference to the accompanying drawings.
Fig. 1 is a flowchart of a preparation method of a MEMS sensor according to an embodiment of the present application, as shown in fig. 1, where the preparation method includes:
step S101, providing a first wafer layer, wherein the first wafer layer has a plurality of first functional electrodes perpendicular to the first wafer layer, and the plurality of first functional electrodes are insulated from each other.
Wherein the first wafer layer is a silicon wafer layer. In particular a highly doped monocrystalline silicon layer. The adjacent first functional electrodes are provided with isolation through holes perpendicular to the first wafer layer, and the plurality of first functional electrodes are mutually isolated and insulated through the isolation through holes. The plurality of first functional electrodes are all silicon material electrodes, and the isolation through holes can be formed by adopting a through silicon via technology (Through Silicon Via, TSV).
Alternatively, the plurality of first functional electrodes may include a first frequency modulation electrode, a mass electrode, a drive detection electrode, a feedback electrode, a detection electrode, and the like.
Step S102, providing a second wafer layer including at least one mass block.
Wherein the second wafer layer is a silicon wafer layer. In particular a highly doped monocrystalline silicon layer.
Step S103, providing a third wafer layer, wherein the third wafer layer is provided with at least one second functional electrode perpendicular to the third wafer layer, and one surface of the third wafer layer for bonding with the second wafer layer is provided with a first groove.
Wherein the third wafer layer is a silicon wafer layer. In particular a highly doped monocrystalline silicon layer. At least one of the second functional electrodes is an electrode of silicon material. In an implementation manner of this embodiment, the at least one second functional electrode may be a second fm electrode, and both the second fm electrode and the first fm electrode may be used to adjust the detection frequency of the MEMS sensor. In other implementations, the at least one second functional electrode may be a driving electrode, a driving detection electrode, a feedback electrode, or another functional electrode such as a detection electrode, which is not limited in this embodiment. The height of the at least one second functional electrode is smaller than the depth of the first recess in a direction perpendicular to the second wafer layer.
In a specific implementation, the first recess may be etched on the third wafer layer.
Step S104, at least one convex supporting structure is formed in the first groove.
Optionally, the at least one raised support structure is the same material as the third wafer layer, and is a single crystal silicon material.
In one implementation of this embodiment, at least one raised support structure may be formed between the anchor structures of the respective masses of the second wafer layer and the third wafer layer. In other implementations of this embodiment, at least one raised support structure may also be disposed between the third wafer layer and other regions of the second wafer layer than the respective masses to prevent contact with the raised support structure when the respective masses vibrate.
Step S105, forming a second insulating layer on a surface of the third wafer layer for bonding with the second wafer layer.
Step S106, forming a third insulating layer on one surface of the at least one protruding support structure for bonding with the second wafer layer.
Step S107, sequentially bonding the first wafer layer, the second wafer layer and the third wafer layer, and enabling each mass block to be suspended on the first wafer layer through an anchor point structure, wherein the mass blocks can vibrate around the anchor point structure along a direction parallel to or perpendicular to the second wafer layer.
In a specific implementation, the first wafer layer, the second wafer layer, and the third wafer layer may be bonded in sequence by a bonding layer. The bonding layer may be, for example, an Au-Si layer, or Si-SiO layer 2 A layer. Alternatively, the first wafer layer, the second wafer layer, and the third wafer layer may be bonded by si—si direct bonding. This embodiment is not limited thereto.
Optionally, before performing step S107, the preparation method may further include:
forming an isolation groove perpendicular to the first wafer layer on the first wafer layer, and dividing the first wafer layer into an inner wafer layer and an outer wafer layer which are isolated from each other in an insulating manner, wherein a plurality of first functional electrodes are positioned on the inner wafer layer; a second conductive via is formed in the second insulating layer and a conductive material is formed in the second conductive via.
At this time, the outer wafer layer and the second wafer layer may be electrically connected to at least one second functional electrode on the third wafer layer through the conductive material in the second conductive hole. The connection of the at least one second functional electrode to the external circuit can be achieved by connecting the outer wafer layer to the external circuit.
Optionally, after performing step S107, the preparation method may further include:
forming a first insulating layer on a surface of the first wafer layer away from the second wafer layer; forming a plurality of first conductive holes in the region of the first insulating layer corresponding to the inner wafer layer, wherein the first conductive holes are in one-to-one correspondence with the first functional electrodes; electrode pads for electrical connection with the corresponding first functional electrodes are formed in the plurality of first conductive holes.
At this time, the plurality of first functional electrodes may be electrically connected to external circuits of different voltages through the corresponding electrode pads, so as to respectively implement different functions.
Optionally, the preparation method may further include:
forming a third conductive hole in a region of the first insulating layer corresponding to the outer wafer layer; an electrode pad for electrical connection with the outer wafer layer is formed in the third conductive via.
At this time, since the at least one second functional electrode is electrically connected to the outer wafer layer, the at least one second functional electrode may be electrically connected to an external circuit through the electrode pad in the third conductive via.
In this embodiment, the electrode pad411 may be a metal electrode pad such as gold, silver, platinum, aluminum, or other conductive alloy materials, which is not limited in the present application.
Optionally, the preparation method further comprises:
and forming a conductive layer on one surface of the third wafer layer, which is far away from the second wafer layer, wherein the conductive layer is electrically connected with at least one second functional electrode. By forming the conductive layer so as to facilitate packaging, the second functional electrode can be electrically connected to an external circuit through the conductive layer.
Optionally, the preparation method further comprises:
a second recess is formed in a face of the second wafer layer for bonding with the first wafer layer.
In a specific implementation, a second recess may be etched in the second wafer layer. By arranging the second grooves, the vibration space of the mass block can be increased, so that the mass block can vibrate in the second grooves and the first grooves along the direction parallel or perpendicular to the second wafer layer.
It should be noted that, in this embodiment, the above-described preparation method may be used to prepare a MEMS gyroscope. In other implementations, the above-described fabrication methods may also be used to fabricate other MEMS sensors such as accelerometers, pressure gauges, resonators, thermometers, and the like. The application is not limited in this regard.
The embodiment of the application also provides a MEMS sensor which is prepared by adopting the preparation method of the embodiment. Fig. 2 is a cross-sectional view of a MEMS sensor according to an embodiment of the present application, and as shown in fig. 2, the MEMS sensor includes a first wafer layer 10, a second wafer layer 20, and a third wafer layer 30 bonded in sequence.
The first wafer layer 10 has a plurality of first functional electrodes 11 perpendicular to the first wafer layer 10, and the plurality of first functional electrodes 11 are insulated from each other.
The second wafer layer 20 comprises at least one mass 21, each mass 21 being suspended from the first wafer layer 10 by an anchor structure 22, and the masses 21 being vibratable around the anchor structure 22 in a direction parallel or perpendicular to the second wafer layer 20.
The third wafer layer 30 has a first recess 30a on a surface bonded to the second wafer layer 20, and the first recess 30a has at least one raised support structure 31 therein. The third wafer layer 30 has at least one second functional electrode 32 thereon that is perpendicular to the third wafer layer 30.
In this embodiment, the MEMS sensor is a MEMS gyroscope. In other implementations, the MEMS sensor may also be an accelerometer, a pressure gauge, a resonator, a thermometer, etc., as the application is not limited in this regard.
The MEMS sensor further comprises a second insulating layer 42 between the third wafer layer 30 and the second wafer layer 20, and a third insulating layer 43 between the raised support structure 31 and the second wafer layer 20.
In this embodiment, the first wafer layer 10, the second wafer layer 20 and the third wafer layer 30 are all silicon wafer layers. In particular a highly doped monocrystalline silicon layer. The adjacent first functional electrodes 11 are provided with isolation through holes 10a perpendicular to the first wafer layer 10, and the plurality of first functional electrodes 11 are isolated from each other by the isolation through holes 10 a. The plurality of first functional electrodes 11 are all silicon material electrodes, and the isolation via 10a may be an insulating silicon via. At least one second functional electrode 32 is located within the first recess 30a, and the height of the at least one second functional electrode 32 is smaller than the depth of the first recess 30a in a direction perpendicular to the second wafer layer 20.
Illustratively, the difference between the height of the at least one second functional electrode 32 and the depth of the first recess 30a is greater than a set value. The set value is the maximum vibration amplitude in the first recess 30a when the mass 21 vibrates in the direction perpendicular to the second wafer layer 20, thereby ensuring that the second functional electrode 32 does not contact the mass 21 when the mass 32 vibrates.
In one implementation of this embodiment, the at least one raised support structure 31 is the same material as the third wafer layer 30, both being a single crystal silicon material. At least one raised support structure 31 may be disposed between the anchor structure 22 of each proof mass 21 of the second wafer layer 20 and the third wafer layer 30. In other implementations of the present embodiment, at least one raised support structure 31 may also be disposed between the third wafer layer 30 and other regions of the second wafer layer 20 than the respective masses 21 to prevent contact with the raised support structure 31 when the respective masses 21 vibrate.
Optionally, the first wafer layer 10 includes an inner wafer layer S1 and an outer wafer layer S2 located outside the inner wafer layer S1, where an isolation groove 10b perpendicular to the first wafer layer 10 is provided between the inner wafer layer S1 and the outer wafer layer S2, and the inner wafer layer S1 and the outer wafer layer S2 are isolated from each other by the isolation groove 10b in an insulating manner. The plurality of first functional electrodes 11 are located on the inner wafer layer S1.
The second insulating layer 42 is provided with a second conductive hole 42a, and the second conductive hole 42a is provided with a conductive material. The outer wafer layer S2, the second wafer layer 20 are electrically connected to at least one second functional electrode 32 on the third wafer layer 30 by a conductive material within the second conductive via 42 a.
Optionally, the MEMS sensor further comprises a first insulating layer 41 on a side of the first wafer layer 10 remote from the second wafer layer 20.
The first insulating layer 41 is provided with a plurality of first conductive holes 41a corresponding to the first functional electrodes 11 one by one, and the first conductive holes 41a are internally provided with electrode pads 411 for electrically connecting with the corresponding first functional electrodes 11. The plurality of first functional electrodes 11 may be electrically connected to an external circuit through the corresponding electrode pad411 to achieve different functions.
In this embodiment, the electrode pad411 may be a metal electrode pad such as gold, silver, platinum, aluminum, or other conductive alloy materials, which is not limited in the present application.
Optionally, a third conductive hole 41b corresponding to the outer wafer layer S2 is formed on the first insulating layer 41, and an electrode pad411 for electrically connecting to the outer wafer layer S2 is disposed in the third conductive hole 41 b.
In the above-described implementation, at least one second functional electrode 32 and a plurality of first functional electrodes 31 may be electrically connected to external circuits of different voltages through the electrode pad411 to respectively implement different functions.
In one implementation of this embodiment, the second wafer layer 20 and the third wafer layer 30 are bonded together by a bonding layer 50, and the bonding layer 50 is a conductive layer. The conductive material within the second conductive via 42a may be a bonding layer 50 to serve both conductive and bonding functions. Specifically, the bonding layer 50 may be an Au-Si layer or an Si-SiO layer 2 A layer.
In other implementations of the present embodiment, the second wafer layer 20 and the first wafer layer 10 are also bonded together by the bonding layer 50. Alternatively, the first wafer layer, the second wafer layer 20 and the third wafer layer 30 may be bonded together by si—si direct bonding. This embodiment is not limited thereto.
Optionally, a conductive layer 60 electrically connected to the at least one second functional electrode 22 is provided on a side of the third wafer layer 30 remote from the second wafer layer 20. By providing the conductive layer 60 for packaging, the second functional electrode 22 can be electrically connected to an external circuit through the conductive layer 60.
In this embodiment, at least one second functional electrode 32 may be electrically connected to an external circuit through the conductive layer 60, or may be electrically connected to the external circuit through the electrode pad411 in the third conductive hole 41b, so as to implement a frequency modulation function.
Optionally, the second wafer layer 20 has a second groove 20a on a surface bonded to the first wafer layer 10. The mass 21 vibrates in the second recess 20a and the first recess 30a in a direction parallel or perpendicular to the second wafer layer 20 to ensure that the mass has a sufficient moving space.
In one implementation of the present embodiment, the plurality of first function electrodes 11 includes a first tuning electrode 11a, and the at least one second function electrode 32 includes a second tuning electrode, and the first tuning electrode 11a and the second tuning electrode are used to adjust a detection frequency of the MEMS sensor.
In other implementations of the present embodiment, the plurality of first functional electrodes 11 further includes a mass electrode 11b, a driving electrode, a driving detection electrode, a feedback electrode, and a detection electrode (not shown in the figure). The second functional electrode 32 may further include a driving electrode, a driving detection electrode, a feedback electrode, or other functional electrodes such as detection electrodes.
Each of the functional electrodes may be connected to an external circuit through a corresponding electrode pad. When the sensor works, the external circuit applies differential driving voltage to the driving electrode to excite the driving mode of the MEMS sensor, and the driving detection electrode can differentially detect the motion state of the driving mode and feed the detection result back to the driving electrode through the external circuit to realize closed-loop driving. The detection electrode can differentially detect the motion state of the MEMS sensor in the detection mode, and the detection result is fed back to the feedback electrode through an external circuit to form closed loop detection.
Fig. 3 is a schematic view of a part of a MEMS sensor according to an embodiment of the present application, and as shown in fig. 3, the second wafer layer 20 includes four masses 21 symmetrically arranged along the center of the sensor, which are respectively denoted as a first mass 21a, a second mass 21b, a third mass 21c and a fourth mass 21d. Wherein the first mass 21a and the third mass 21c are axisymmetrically arranged about the negative X-axis direction; the second mass 21b and the fourth mass 21d are axisymmetrically arranged about the positive X-axis direction; the first mass 21a and the second mass 21b are axisymmetrically arranged about the Y-axis positive direction; the third mass 21c and the fourth mass 21d are axisymmetrically arranged about the Y-axis negative direction; the first mass block 21a and the fourth mass block 21d are arranged in a central symmetry manner; the third mass 21c is arranged centrally symmetrically to the second mass 21 b. The mass blocks are connected through coupling elastic beams.
Wherein, a three-dimensional space coordinate system comprising an X axis, a Y axis and a Z axis is established by taking the center point of the second wafer layer 20 as an origin, the X axis and the Y axis are parallel to the end face of the second wafer layer 20, and the Z axis is perpendicular to the end face of the second wafer layer 20.
In this embodiment, the third wafer layer 30 has a second fm electrode disposed corresponding to each mass block, and the first wafer layer 10 has a first fm electrode 11a, a mass block electrode, a driving detection electrode, a feedback electrode, and a detection electrode (not shown) disposed corresponding to each mass block, so as to respectively perform the functions of driving, detecting, and the like for each mass block.
The technical scheme provided by the embodiment of the application has at least the following technical effects or advantages:
according to the manufacturing method of the MEMS sensor and the MEMS sensor provided by the embodiment of the application, at least one protruding support structure is arranged in the first groove of the third wafer layer, and the protruding support structure can play a supporting role, so that the structural strength between the third wafer layer and the second wafer layer is enhanced. Meanwhile, by forming a second insulating layer between the third wafer layer and the second wafer layer and forming a third insulating layer between the bump support structure and the second wafer layer, electrical insulation of the third wafer layer from the second wafer layer is achieved. At this time, the space of the third wafer layer can be utilized to set at least one second functional electrode on the third wafer layer, so as to further meet the setting requirement of the MEMS sensor on the functional electrode.
In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the application may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.
Similarly, it should be appreciated that in the foregoing description of exemplary embodiments of the application, various features of the application are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. However, the disclosed method should not be construed as reflecting the intention that: i.e., the claimed application requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this application.
It should be noted that the above-mentioned embodiments illustrate rather than limit the application, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The application may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The use of the words first, second, third, etc. do not denote any order. These words may be interpreted as names.

Claims (10)

1. A method of manufacturing a MEMS sensor, the method comprising:
providing a first wafer layer, wherein a plurality of first functional electrodes perpendicular to the first wafer layer are arranged on the first wafer layer, and the first functional electrodes are mutually insulated;
providing a second wafer layer, wherein the second wafer layer comprises at least one mass block;
providing a third wafer layer, wherein the third wafer layer is provided with at least one second functional electrode perpendicular to the third wafer layer, and one surface of the third wafer layer, which is used for bonding with the second wafer layer, is provided with a first groove;
forming at least one raised support structure within the first recess;
forming a second insulating layer on one surface of the third wafer layer for bonding with the second wafer layer;
forming a third insulating layer on a surface of the at least one raised support structure for bonding with the second wafer layer;
and sequentially bonding the first wafer layer, the second wafer layer and the third wafer layer, and enabling each mass block to be suspended on the first wafer layer through an anchor point structure, wherein the mass blocks can vibrate around the anchor point structure along a direction parallel to or perpendicular to the second wafer layer.
2. The method of manufacturing of claim 1, wherein prior to bonding the first wafer layer, the second wafer layer, and the third wafer layer in that order, the method of manufacturing further comprises:
forming an isolation groove perpendicular to the first wafer layer on the first wafer layer, and dividing the first wafer layer into an inner wafer layer and an outer wafer layer which are isolated from each other in an insulating manner, wherein the plurality of first functional electrodes are positioned on the inner wafer layer;
and forming a second conductive hole on the second insulating layer, and forming a conductive material in the second conductive hole.
3. The method of manufacturing of claim 2, wherein after the sequentially bonding the first wafer layer, the second wafer layer, and the third wafer layer, the method of manufacturing further comprises:
forming a first insulating layer on a side of the first wafer layer away from the second wafer layer;
forming a plurality of first conductive holes in the region of the first insulating layer corresponding to the inner wafer layer, wherein the first conductive holes are in one-to-one correspondence with the first functional electrodes;
and forming electrode pads for electrically connecting with the corresponding first functional electrodes in the first conductive holes.
4. A method of preparing according to claim 3, further comprising:
forming a third conductive hole in a region of the first insulating layer corresponding to the outer wafer layer;
and forming an electrode pad in the third conductive hole, wherein the electrode pad is used for being electrically connected with the outer wafer layer.
5. The method of manufacturing according to claim 1, characterized in that the method of manufacturing further comprises:
and forming a conductive layer on one surface of the third wafer layer, which is far away from the second wafer layer, wherein the conductive layer is electrically connected with the at least one second functional electrode.
6. The method of manufacturing according to claim 1, characterized in that the method of manufacturing further comprises:
and forming a second groove on one surface of the second wafer layer bonded with the first wafer layer.
7. A MEMS sensor, characterized in that it is manufactured by the manufacturing method according to any one of the preceding claims 1 to 6, comprising a first wafer layer, a second wafer layer and a third wafer layer bonded in sequence;
the first wafer layer is provided with a plurality of first functional electrodes perpendicular to the first wafer layer, and the first functional electrodes are mutually insulated;
the second wafer layer comprises at least one mass block, each mass block is suspended on the first wafer layer through an anchor point structure, and the mass blocks can vibrate around the anchor point structure along a direction parallel to or perpendicular to the second wafer layer;
a first groove is formed in one surface of the third wafer layer, which is bonded with the second wafer layer, at least one protruding supporting structure is arranged in the first groove, and at least one second functional electrode perpendicular to the third wafer layer is arranged on the third wafer layer;
the MEMS sensor further includes a second insulating layer between the third wafer layer and the second wafer layer, and a third insulating layer between the raised support structure and the second wafer layer.
8. The MEMS sensor of claim 7, wherein the first wafer layer comprises an inner wafer layer and an outer wafer layer located outside the inner wafer layer, wherein an isolation trench perpendicular to the first wafer layer is provided between the inner wafer layer and the outer wafer layer, wherein the inner wafer layer and the outer wafer layer are isolated from each other by the isolation trench, and wherein the plurality of first functional electrodes are located on the inner wafer layer;
and a second conductive hole is formed in the second insulator, a conductive material is arranged in the second conductive hole, and the outer wafer layer and the second wafer layer are electrically connected with the at least one second functional electrode on the third wafer layer through the conductive material in the second conductive hole.
9. The MEMS sensor of claim 8, further comprising a first insulating layer on a side of the first wafer layer remote from the second wafer layer;
a plurality of first conductive holes corresponding to the first functional electrodes one by one are formed in the first insulating layer, and electrode pads used for being electrically connected with the corresponding first functional electrodes are arranged in the first conductive holes.
10. The MEMS sensor of claim 9, wherein a third conductive via corresponding to the outer wafer layer is formed in the first insulating layer, and an electrode pad for electrically connecting to the outer wafer layer is disposed in the third conductive via.
CN202310596728.4A 2023-05-24 2023-05-24 MEMS sensor and preparation method thereof Pending CN116605834A (en)

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