CN116609550B - MEMS accelerometer and preparation method thereof - Google Patents
MEMS accelerometer and preparation method thereof Download PDFInfo
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- CN116609550B CN116609550B CN202310310799.3A CN202310310799A CN116609550B CN 116609550 B CN116609550 B CN 116609550B CN 202310310799 A CN202310310799 A CN 202310310799A CN 116609550 B CN116609550 B CN 116609550B
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- 238000002360 preparation method Methods 0.000 title abstract description 6
- 239000000463 material Substances 0.000 claims abstract description 162
- 239000000758 substrate Substances 0.000 claims abstract description 35
- 238000004519 manufacturing process Methods 0.000 claims abstract description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 6
- 235000012239 silicon dioxide Nutrition 0.000 claims description 6
- 239000000377 silicon dioxide Substances 0.000 claims description 6
- 229910021421 monocrystalline silicon Inorganic materials 0.000 claims description 5
- 229910052782 aluminium Inorganic materials 0.000 claims description 4
- 229910021420 polycrystalline silicon Inorganic materials 0.000 claims description 4
- 229910052581 Si3N4 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
- 230000006698 induction Effects 0.000 claims description 2
- 238000010030 laminating Methods 0.000 claims 2
- 230000001133 acceleration Effects 0.000 abstract description 18
- 230000009471 action Effects 0.000 description 6
- 230000007423 decrease Effects 0.000 description 4
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- 230000000670 limiting effect Effects 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
- 239000011521 glass Substances 0.000 description 3
- 238000000206 photolithography Methods 0.000 description 3
- 238000000623 plasma-assisted chemical vapour deposition Methods 0.000 description 3
- 238000005530 etching Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229940024548 aluminum oxide Drugs 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
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- 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]
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- 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
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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
- B81C1/00134—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems comprising flexible or deformable structures
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
- G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
- G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
- G01P15/12—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by alteration of electrical resistance
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- 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
- B81B2201/0228—Inertial sensors
- B81B2201/0235—Accelerometers
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- 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
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Abstract
The embodiment of the disclosure provides a MEMS accelerometer and a preparation method thereof. The MEMS accelerometer includes: a substrate; the support column is arranged on the substrate; the first connecting beam is arranged on one side of the support column, which is away from the substrate; the second connecting beam is arranged on the substrate and is arranged at an interval opposite to the first connecting beam; the sensing element and the mass block are arranged on the second connecting beam; the double-material elastic support component is positioned between the first connecting beam and the second connecting beam, two ends of the double-material elastic support component are respectively connected with the first connecting beam and the second connecting beam, and the double-material elastic support component is formed by manufacturing two materials with different expansion coefficients. The MEMS accelerometer can effectively reduce the possibility of fracture of the second connecting beam when the accelerometer bears larger acceleration, and has certain overload resistance; in addition, the mass block can be prevented from being displaced when not receiving acceleration, so that the zero drift phenomenon of the accelerometer is restrained; finally, temperature drift compensation of the accelerometer can also be achieved.
Description
Technical Field
The disclosure belongs to the technical field of sensors, and particularly relates to a MEMS accelerometer and a preparation method thereof.
Background
The accelerometer can convert acceleration signals into electric signals so as to be convenient for measurement, and is widely applied to the fields of industrial control, aerospace, automobile electronics and the like. Based on MEMS
The accelerometer manufactured by the technology has the advantages of small volume, high precision, easy integration and the like. The MEMS piezoresistive accelerometer has the advantages of good linearity and reliability, simple peripheral circuit and the like, thereby becoming the first choice of the design of a high-range micro accelerometer and being widely applied to the measurement of impact environment. Typical MEMS piezoresistive accelerometers generally employ a mass-to-beam structure. When external acceleration is applied to the mass block, the mass block drives the connecting beam to generate strain, the resistance value of the piezoresistor positioned on the connecting beam is changed, and the piezoresistor is converted into an electric signal through the Wheatstone bridge to be output. However, the MEMS piezoresistive accelerometer generally has a temperature drift problem, that is, the resistivity of the piezoresistor changes due to temperature changes, and then the resistance of the piezoresistor changes, so that the output precision of the sensor is reduced. In addition, the traditional MEMS accelerometer realizes high sensitivity, and the connecting beam is generally arranged to be slender, so that the mechanical strength is low, the overload resistance is poor, and the application range of the accelerometer is limited
Disclosure of Invention
The disclosure aims to at least solve one of the technical problems existing in the prior art, and provides a MEMS accelerometer and a preparation method thereof.
In one aspect of the present disclosure, there is provided a MEMS accelerometer, the MEMS accelerometer comprising:
A substrate;
the support column is arranged on the substrate;
the first connecting beam is arranged on one side, away from the substrate, of the supporting column;
the second connecting beam is arranged on the substrate and is arranged at an interval opposite to the first connecting beam;
the sensing element and the mass block are arranged on the second connecting beam;
The double-material elastic support assembly is located between the first connecting beam and the second connecting beam, two ends of the double-material elastic support assembly are respectively connected with the first connecting beam and the second connecting beam, and the double-material elastic support assembly is formed by manufacturing materials with two different expansion coefficients.
In some alternative embodiments, the bi-material resilient support assembly comprises:
The first end of the elastic piece is connected with the first connecting beam, and the second end of the elastic piece is connected with the second connecting beam;
the double-material layer comprises a first material layer and a second material layer which are sequentially stacked, wherein both ends of the first material layer and both ends of the second material layer are respectively connected with the elastic piece, and the expansion coefficient of the first material layer is larger than that of the second material layer.
In some alternative embodiments, the bi-material resilient support assembly includes two sets of bi-material layers disposed in opposed spaced relation;
A first material layer of a group of bi-material layers facing one side of the first connecting beam is arranged away from the first connecting beam, and a second material layer is arranged close to the first connecting beam;
the first material layer of the group of bi-material layers facing towards the side of the second connection beam is arranged away from the second connection beam, and the second material layer is arranged close to the second connection beam.
In some alternative embodiments, the mass is located in a central region of the substrate, and the second connection beams are disposed around the mass and are located at central regions of each side of the mass, respectively.
In some alternative embodiments, the bi-material resilient support assembly is disposed in correspondence with the sensing element.
In some alternative embodiments, the MEMS accelerometer includes four sensing elements;
The four sensing elements are respectively located at one side of the substrate corresponding to the second connection Liang Beili, two of the sensing elements are located at one side of the second connection beam close to the mass block, and the other two sensing elements are located at one side of the second connection beam far away from the mass block.
In some alternative embodiments, the first material layer is formed from one of Al, cu, au, and Mo materials; and/or the number of the groups of groups,
The thickness of the first material layer ranges from 100nm to 2000nm.
In some alternative embodiments, the second material layer is formed from one of monocrystalline silicon, polycrystalline silicon, silicon dioxide, and silicon nitride; and/or the number of the groups of groups,
The thickness of the second material layer ranges from 100nm to 2000nm.
In some alternative embodiments, the sensing element employs a piezo-resistor.
In another aspect of the present disclosure, a method of manufacturing a MEMS accelerometer is provided, the method comprising:
providing a substrate and a first connection beam;
forming a second connection beam and a mass block pattern on the upper surface of the substrate;
releasing the second connection beam and the mass at the back side of the substrate;
P-type doping is carried out on the second connecting beam, so that an induction element is formed;
Preparing a bi-material elastic support assembly on the second connection beam; wherein the bi-material elastic support component is formed by two materials with different expansion coefficients;
Forming a support column matched with the height of the bi-material elastic support component on the upper surface of the substrate;
And combining the lower surface of the first connecting beam with the upper surfaces of the support columns and the bi-material elastic support assembly to obtain the MEMS accelerometer.
According to the MEMS accelerometer and the preparation method thereof, the arranged bi-material elastic support component has a limiting effect on the movable space of the second connecting beam, so that the possibility that the second connecting beam breaks when the accelerometer bears larger acceleration is effectively reduced, and the accelerometer has certain overload resistance. The lifting action of the first connecting beam and the bi-material elastic support assembly on the mass block is counteracted with the self gravity of the mass block, so that the mass block can be prevented from being displaced when not subjected to acceleration, and the zero drift phenomenon of the accelerometer is restrained. And the dual-material elastic support component is made of two materials with different expansion coefficients, so that temperature drift compensation of the accelerometer is realized.
Drawings
FIG. 1 is a schematic structural view of one embodiment of a MEMS accelerometer of the present disclosure;
FIG. 2 is a top view of the MEMS accelerometer shown in FIG. 1;
FIG. 3 is a schematic diagram of a Wheatstone bridge of a MEMS accelerometer of the disclosure;
fig. 4-11 are flowcharts of one embodiment of a method of preparing a MEMS acceleration of the present disclosure.
Detailed Description
In order that those skilled in the art will better understand the technical solutions of the present disclosure, the present disclosure will be described in further detail with reference to the accompanying drawings and detailed description.
As shown in fig. 1 and 2, embodiments of the present disclosure relate to a MEMS accelerometer, the MEMS accelerometer comprising: the device comprises a first connecting beam 1, a supporting column 2, a second connecting beam 5, a substrate 6, a bi-material elastic support assembly 7, a mass block 8 and a sensing element 9.
Specifically, as shown in fig. 1 and 2, in some embodiments, the first connecting beam 1 is at least one of monocrystalline silicon or glass, and has a thickness ranging from 5 μm to 200 μm, the first connecting beam 1 connects the support column 2 and the upper end of the bi-material elastic support assembly 7, one end of the first connecting beam 1 is connected to the support column 2, and the other end is connected to the bi-material elastic support assembly 7, and the width is equal to or slightly greater than the width of the support column 2.
With continued reference to fig. 1 and 2, in some embodiments, the support columns 2 are made of at least one of monocrystalline silicon, polycrystalline silicon or silicon dioxide, and have a thickness ranging from 5 μm to 100 μm, and the support columns 2 are symmetrically disposed below the first connection beams 1 and supported on the upper surface of the substrate 1, and the support columns and the first connection beams 1 together play a role in fixing the upper ends of the bi-material elastic support assemblies 7.
With continued reference to fig. 1 and 2, in some embodiments, the MEMS accelerometer includes four first connection beams 1 and four second connection beams 5, the four second connection beams 5 being located on the upper surface of the substrate 6, around the mass 8, respectively at the midpoints of each side of the mass 8, the second connection beams 5 having a thickness in the range of 2um to 200 um.
In some embodiments, referring to fig. 1-3 together, the mems accelerometer includes four sensing elements 9, the sensing elements 9 being piezoresistors. The four inductive elements 9 are each located on the side of the corresponding second connection beam 5 facing away from the substrate 6, i.e. on the upper surface of the second connection beam 5, and two of them are located on the side of the second connection beam 5 adjacent to the mass 8, the remaining two are located on the side of the second connection beam 5 facing away from the mass 8. The function of the arrangement is that opposite resistance changes are generated between every two sensing elements 9 under the action of acceleration, and the four sensing elements 9 are connected in a Wheatstone bridge mode, so that acceleration signals can be converted into electric signals output by the Wheatstone bridge.
In some embodiments, as shown in fig. 1 and 2, the mass 8 is located in a central region of the substrate 6, with a thickness ranging from 2 μm to 400 μm.
In some embodiments, as shown in fig. 1 and 2, the bi-material elastic support member 7 is located between the first connection beam 1 and the second connection beam 5, and both ends of the bi-material elastic support member 7 are connected to the first connection beam 1 and the second connection beam 5, respectively. That is, the bi-material elastic support member 7 has one end connected to the first connection beam 1 and the other end connected to the second connection beam 5, thereby limiting the movable space of the second connection beam 5, and thus effectively reducing the possibility of breakage of the second connection beam 5 when the accelerometer is subjected to a large acceleration, so that the MEMS acceleration of the present embodiment has overload resistance. In addition, the lifting action of the first connecting beam 1 and the bi-material elastic support assembly 7 on the mass block 8 is counteracted with the gravity of the mass block 8, so that the mass block 8 can be prevented from being displaced when not subjected to acceleration, and the zero drift phenomenon of the accelerometer is restrained. In addition, the bi-material elastic support component 7 is made of two materials with different expansion coefficients, and can effectively compensate the output reduction caused by temperature rise when the temperature rises due to the different thermal expansion coefficients of the materials; when the approximate temperature is reduced, the bi-material elastic support assembly can effectively compensate the output increase caused by the temperature reduction. Therefore, the MEMS accelerometer of the embodiment also realizes temperature drift compensation of the accelerometer through the arranged bi-material elastic support component.
According to the MEMS accelerometer, through the arranged bi-material elastic support component, the bi-material elastic support component plays a role in limiting the movable space of the second connecting beam, so that the possibility that the second connecting beam breaks when the accelerometer bears larger acceleration is effectively reduced, and the accelerometer has certain overload resistance. The lifting action of the first connecting beam and the bi-material elastic support assembly on the mass block is counteracted with the self gravity of the mass block, so that the mass block can be prevented from being displaced when not subjected to acceleration, and the zero drift phenomenon of the accelerometer is restrained. And the dual-material elastic support component is made of two materials with different expansion coefficients, so that temperature drift compensation of the accelerometer is realized.
Illustratively, as shown in fig. 1 and 2, the bi-material elastic support assembly 7 includes: an elastic member (not numbered in the figure) and two sets of bi-material layers arranged at opposite intervals, wherein a first end of the elastic member is connected with the first connecting beam 1, and a second end of the elastic member is connected with the second connecting beam 5. Each group of double-material layers comprises a first material layer 3 and a second material layer 4 which are sequentially stacked, wherein both ends of the first material layer 3 and both ends of the second material layer 4 are respectively connected with the elastic piece, and the expansion coefficient of the first material layer 3 is larger than that of the second material layer 4.
Specifically, as shown in fig. 1 and 2, the first material layer 3 and the second material layer 4 together form a horizontally disposed bi-material layer in the bi-material elastic support member 7. The first material layer 3 of the set of bi-material layers facing the side of the first connection beam 1 is arranged away from the first connection beam 1 and the second material layer 4 is arranged close to the first connection beam 1. The first material layer 3 of the set of bi-material layers facing the side of the second connection beam 5 is arranged away from the second connection beam 5 and the second material layer 4 is arranged close to the second connection beam 5. That is, as shown in fig. 1, the second material layer 4 is located above the first material layer 3 on the side of the bi-material elastic support member 7 adjacent to the first connection beam 1, and the first material layer 3 is located above the second material layer 4 on the side of the bi-material elastic support member 7 adjacent to the second connection beam 5.
It should be noted that, the bi-material elastic support assembly in the MEMS accelerometer includes two sets of bi-material layers, and those skilled in the art may design other sets of bi-material layers according to actual needs, which is not limited in this embodiment.
In some embodiments, the material of the first material layer 3 is Al, cu, au, mo or the like with a higher thermal expansion coefficient, the thickness is in the range of 100nm to 2000nm, the material of the second material layer 4 is monocrystalline silicon, polycrystalline silicon, silicon dioxide or silicon nitride or the like with a lower thermal expansion coefficient, the thickness is in the range of 100nm to 2000nm, and the thickness of the first material layer 3 is the same as the thickness of the second material layer 4.
In some embodiments, as shown in fig. 1 and 2, the lower end of the bi-material elastic support member 7 is disposed above the sensing element 9 (i.e., the varistor). When the temperature rises, the resistivity of the piezoresistor is reduced, the resistance value is reduced, the output of the accelerometer is reduced, the first material layer 3 expands more than the second material layer 4 in volume due to the difference of the thermal expansion coefficients of the materials, the bi-material elastic support assembly 7 stretches, and compressive stress is applied to the first connecting beam 1 and the second connecting beam 5, so that the resistance value of the piezoresistor is increased, and the output reduction caused by temperature rise is compensated. Similarly, when the temperature is reduced, the piezoresistive coefficient of the piezoresistor is increased, the output of the accelerometer is increased, the second material layer 4 is larger than the volume expansion of the first material layer 3, the bi-material elastic support assembly 7 is contracted, and a tensile stress is applied to the first connecting beam 1 and the second connecting beam 5, so that the resistance value of the piezoresistor is reduced, and the output increase caused by temperature reduction is compensated. In summary, the dual-material elastic support assembly of the embodiment realizes temperature drift compensation for the accelerometer
The MEMS accelerometer of the present disclosure works as follows:
as shown in fig. 1 to 3, the mass block 8 drives the second connecting beam 5 to generate displacement under the action of external acceleration, the stress distribution on the second connecting beam 5 changes, the stress close to the mass block 8 and the stress far away from the mass block 8 are opposite in direction, so that piezoresistors R1, R2, R3 and R4 distributed on the mass block are caused to generate reverse resistance change, and four piezoresistors are interconnected to form a wheatstone bridge, and therefore the acceleration can be detected by detecting the voltage output by the wheatstone bridge.
When the temperature rises, the resistivity of the piezoresistor decreases, and thus the resistance value decreases, resulting in a decrease in the output of the accelerometer, and the first material layer 3 expands more than the second material layer 4 in volume due to the difference in thermal expansion coefficients of the materials, and the bi-material elastic support member 7 stretches while applying compressive stress to the first connection beam 1 and the second connection beam 5, resulting in an increase in the resistance value of the piezoresistor, thereby compensating for a decrease in the output caused by the temperature rise. Similarly, when the temperature is reduced, the resistivity of the piezoresistor is increased, and then the resistance is increased, so that the output of the accelerometer is increased, the second material layer is larger than the first material layer 3 in volume expansion, the bi-material elastic support assembly 7 is contracted, and simultaneously, the tensile stress is applied to the first connecting beam 1 and the second connecting beam 5, so that the resistance of the piezoresistor is reduced, and the output increase caused by cooling is compensated, so that the temperature drift compensation of the accelerometer is realized.
In addition, the bi-material elastic support member 7 has one end connected to the first connection beam 1 and one end connected to the second connection beam 5, thus limiting the movable space of the second connection beam 5, thereby effectively reducing the possibility of breakage of the second connection beam 5 when the accelerometer is subjected to a large acceleration, and thus the MEMS accelerometer of the present disclosure has overload resistance. The lifting action of the first connecting beam 1 and the bi-material elastic support assembly 7 on the mass block 8 is counteracted with the self gravity of the mass block 8, so that the mass block 8 can be prevented from being displaced when not subjected to acceleration, and the zero drift phenomenon of the accelerometer is restrained.
In another aspect of the embodiments of the present disclosure, a method for manufacturing a MEMS accelerometer is provided, and the structure of the MEMS accelerometer may be described in the foregoing related description, which is not repeated herein. The method comprises the following steps:
Step one, providing a substrate.
Specifically, as shown in FIG. 4, an N-type (100) silicon wafer having a thickness of 500 μm was prepared as the substrate layer 6.
And step two, forming a second connecting beam and a mass block pattern on the upper surface of the substrate.
Specifically, as shown in fig. 5, the second connection beam 5 and the mass 8 are patterned by photolithography and etching of the upper surface of the substrate 6.
And thirdly, releasing the second connecting beam and the mass block on the back surface of the substrate.
Specifically, as shown in fig. 6, the second connection beam 5 and the mass block 8 are released by back side lithography and etching.
And step four, performing P-type doping on the second connecting beam to form the sensing element.
Specifically, as shown in fig. 7 and 8, the second connection beam 5 is doped P-type by ion implantation to form four piezoresistors.
Step five, preparing a bi-material elastic support assembly on the second connecting beam; wherein the bi-material resilient support assembly is formed from two materials of different coefficients of expansion.
Specifically, as shown in fig. 9, four aluminum and silicon dioxide bi-material flexible support members 7 having a height of 5 μm were prepared by photolithography, magnetron sputtering, and Plasma Enhanced Chemical Vapor Deposition (PECVD).
And step six, forming support columns on the upper surface of the substrate, wherein the height of the support columns is matched with that of the bi-material elastic support component.
Specifically, as shown in fig. 10, the silicon dioxide support columns 2 having the same height as the bi-material elastic support members 7 are formed by photolithography and PECVD.
And step seven, combining the lower surface of the first connecting beam with the upper surfaces of the support columns and the bi-material elastic support assembly to obtain the MEMS accelerometer.
Specifically, as shown in fig. 11, four glass sheets having a thickness of 5 μm were prepared as the first connection beams 1, and the lower surfaces of the glass sheets were bonded to the support columns 2 and the upper surfaces of the bi-material elastic support members 7 by an assembly process, thereby completing the fabrication of the MEMS accelerometer of the present invention.
It is to be understood that the above embodiments are merely exemplary embodiments employed to illustrate the principles of the present disclosure, however, the present disclosure is not limited thereto. Various modifications and improvements may be made by those skilled in the art without departing from the spirit and substance of the disclosure, and are also considered to be within the scope of the disclosure.
Claims (8)
1. A MEMS accelerometer, comprising:
A substrate;
the support column is arranged on the substrate;
the first connecting beam is arranged on one side, away from the substrate, of the supporting column;
the second connecting beam is arranged on the substrate and is arranged at an interval opposite to the first connecting beam;
the sensing element and the mass block are arranged on the second connecting beam;
The two-material elastic support component is positioned between the first connecting beam and the second connecting beam, two ends of the two-material elastic support component are respectively connected with the first connecting beam and the second connecting beam, and the two-material elastic support component is made of two materials with different expansion coefficients;
The bi-material resilient support assembly includes:
The first end of the elastic piece is connected with the first connecting beam, and the second end of the elastic piece is connected with the second connecting beam;
Two sets of bi-material layers of relative interval setting, bi-material layer is including laminating in proper order setting and the first material layer and the second material layer that the level was placed, first material layer with the both ends of second material layer all respectively with the elastic component is connected, the expansion coefficient of first material layer is greater than the expansion coefficient of second material layer, and
A first material layer of a group of bi-material layers facing one side of the first connecting beam is arranged away from the first connecting beam, and a second material layer is arranged close to the first connecting beam; the first material layer of the group of bi-material layers facing towards the side of the second connection beam is arranged away from the second connection beam, and the second material layer is arranged close to the second connection beam.
2. The MEMS accelerometer of claim 1, wherein the mass is located at a central region of the substrate, and the second connection beams are disposed around the mass and are located at central regions of each side of the mass, respectively.
3. The MEMS accelerometer of claim 1, wherein the bi-material resilient support assembly is disposed in correspondence with the sensing element.
4. A MEMS accelerometer according to any one of claims 1 to 3, wherein the MEMS accelerometer comprises four sensing elements;
The four sensing elements are respectively located at one side of the substrate corresponding to the second connection Liang Beili, two of the sensing elements are located at one side of the second connection beam close to the mass block, and the other two sensing elements are located at one side of the second connection beam far away from the mass block.
5. A MEMS accelerometer according to any one of claims 1 to 3, wherein the first material layer is formed from one of Al, cu, au and Mo materials; and/or the number of the groups of groups,
The thickness of the first material layer ranges from 100nm to 2000nm.
6. A MEMS accelerometer according to any one of claims 1 to 3, wherein the second material layer is formed from one of monocrystalline silicon, polycrystalline silicon, silicon dioxide and silicon nitride; and/or the number of the groups of groups,
The thickness of the second material layer ranges from 100nm to 2000nm.
7. A MEMS accelerometer according to any one of claims 1 to 3, wherein the sensing element employs a piezo-resistor.
8. A method of manufacturing a MEMS accelerometer, the method comprising:
providing a substrate and a first connection beam;
forming a second connection beam and a mass block pattern on the upper surface of the substrate;
releasing the second connection beam and the mass at the back side of the substrate;
P-type doping is carried out on the second connecting beam, so that an induction element is formed;
Preparing a bi-material elastic support assembly on the second connection beam; wherein the bi-material elastic support component is formed by two materials with different expansion coefficients;
Forming a support column matched with the height of the bi-material elastic support component on the upper surface of the substrate;
combining the lower surface of the first connecting beam with the upper surfaces of the support columns and the bi-material elastic support assembly to obtain the MEMS accelerometer; wherein,
The bi-material resilient support assembly includes:
The first end of the elastic piece is connected with the first connecting beam, and the second end of the elastic piece is connected with the second connecting beam;
Two sets of bi-material layers of relative interval setting, bi-material layer is including laminating in proper order setting and the first material layer and the second material layer that the level was placed, first material layer with the both ends of second material layer all respectively with the elastic component is connected, the expansion coefficient of first material layer is greater than the expansion coefficient of second material layer, and
A first material layer of a group of bi-material layers facing one side of the first connecting beam is arranged away from the first connecting beam, and a second material layer is arranged close to the first connecting beam; the first material layer of the group of bi-material layers facing towards the side of the second connection beam is arranged away from the second connection beam, and the second material layer is arranged close to the second connection beam.
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| TWI477780B (en) * | 2011-10-12 | 2015-03-21 | Richwave Technology Corp | Piezoresistive type z-axis accelerometer |
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| US5922955A (en) * | 1995-06-14 | 1999-07-13 | Commissariat A L'energie Atomique | Gravity-compensation type accelerometer and process for producing such an accelerometer |
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