Electrostatic excitation detection cantilever beam resonance device and accelerometer

Abstract

The invention provides a cantilever beam resonance device for electrostatic excitation detection and an accelerometer, and relates to the technical field of micromechanical electronic sensors, the resonance device comprises an excitation detection mechanism and a resonance mechanism; the resonance mechanism comprises a cantilever beam with one fixed end and one free end and a fixing unit, the excitation detection mechanism comprises an excitation unit and a detection unit which are located on the two sides of the cantilever beam respectively, and one end of the cantilever beam is fixedly connected with the fixing unit. The accelerometer comprises the resonance device, a cover plate, a device layer and a substrate layer, the device layer is sealed between the cover plate and the substrate layer in a vacuum mode, the device layer is provided with a mass block, a supporting beam, a connecting unit and other acceleration sensitive mechanisms, the cantilever beam is suspended above the substrate layer, and the mass block is connected to the fixed end of the cantilever beam through the connecting unit. The cantilever beam structure is used as a resonance unit, the vibration amplitude of a harmonic oscillator is large, the quality factor and the frequency resolution of the sensor are improved, the excitation detection difficulty is reduced, and subsequent structure parameter optimization is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of micro-mechanical electronic sensors, and in particular to a cantilever beam resonance device and an accelerometer for electrostatic excitation detection. Background Art

[0002] MEMS silicon micromechanical resonant accelerometer is an instrument that measures acceleration by detecting the change in the natural frequency of the resonant beam. Compared with traditional sensors, resonant accelerometers have the advantages of small size, light weight, easy integration, high measurement accuracy and mass production. It has broad development prospects in the future.

[0003] The current mainstream MEMS resonant accelerometers still have some deficiencies in terms of excitation and detection. Traditional MEMS resonant sensors usually use a double-ended fixed beam as a frequency conversion structure, such as Figure 1 As shown in the figure, although the vibration mode of this structure is stable, it also has the disadvantages of small amplitude and difficult excitation. This disadvantage can lead to the phenomenon of too small detection current signal and loss of detection signal, thus causing errors. Both ends of the double-end clamped beam structure are fixed ends, which usually requires the size adjustment of the overall structure when optimizing the parameters of the resonator. However, the change of the overall structure will cause the structural performance to change in an unknown direction, which brings difficulties to parameter optimization. In addition, due to the constraint of the two free ends, the double-end clamped beam has a higher damping effect in air and water, which reduces the structural quality factor and thus affects the detection accuracy.

[0004] Therefore, how to provide a MEMS silicon micromechanical resonant acceleration sensor with large resonator vibration amplitude, easy excitation detection, high quality factor, and good parameter adjustability is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] The object of the present invention is to provide a cantilever beam resonance device and an accelerometer for electrostatic excitation detection, which have large resonator vibration amplitude, are easy to excite and detect, have high quality factor and good parameter adjustability.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a cantilever beam resonance device for electrostatic excitation detection, comprising an excitation detection mechanism and a resonance mechanism; the resonance mechanism comprises a cantilever beam and a fixed unit, and the excitation detection mechanism comprises an excitation unit and a detection unit respectively located on both sides of the cantilever beam; one end of the cantilever beam is fixedly connected to the fixed unit, which is the fixed end of the cantilever beam, and the other end is a free end.

[0008] In order to further ensure the resonance effect of the cantilever beam, the present invention provides a preferred solution in the first aspect, wherein the cantilever beam includes a main body and two oppositely arranged beam feet fixedly connected to the main body, there is a gap between the beam feet, the fixing unit is fixedly connected to one of the beam feet, the top of the main body is the free end, and the beam feet are the fixed ends.

[0009] In order to better transfer stress, the present invention provides a preferred solution in the first aspect, wherein the beam feet are arranged on the main body in parallel with each other.

[0010] In a second aspect, the present invention provides an accelerometer, comprising the above-mentioned cantilever beam resonance device for electrostatic excitation detection, and also comprising a cover plate, a device layer and a base layer, wherein the device layer is vacuum-sealed between the cover plate and the base layer, and the device layer comprises an acceleration sensitive mechanism; the acceleration sensitive mechanism comprises a mass block, a support beam and a connecting unit; the mass block, the support beam, the connecting unit and the cantilever beam are suspended above the base layer; the support beam is fixedly connected to the mass block for supporting the mass block to be suspended in the air; the mass block is connected to the fixed end of the cantilever beam through the connecting unit.

[0011] Preferably, the accelerometer further comprises a sacrificial layer between the device layer and the base layer, the fixing unit, the excitation unit and the detection unit are connected to the base layer through the sacrificial layer, and the mass block, the support beam, the connection unit and the cantilever beam are suspended by releasing the sacrificial layer. This suspension processing method has good process compatibility and good application value.

[0012] Furthermore, the sacrificial layer is released for suspension treatment by opening a release hole on the front side to release the sacrificial layer and / or engraving the sacrificial layer on the back side to release the sacrificial layer. The suspension treatment process has many options and good application value.

[0013] Preferably, the cover plate and / or the base layer is provided with a metal-filled hole, the metal-filled hole leads to the device layer, the metal-filled hole is filled with a metal material for leading out the signal of the device layer, and the metal-filled hole is obtained by etching through the TSV silicon via technology or the TGV glass via technology.

[0014] Preferably, the device layer is etched and released based on an SOI wafer, the cover plate is made of glass, the base layer is made of silicon, and after the cover plate is cavity etched, the device layer is vacuum-encapsulated between the cover plate and the base layer using a silicon-glass bonding process. The process is simple and has good application value.

[0015] Compared with the prior art, the above technical solution has the following advantages:

[0016] The present invention adopts a cantilever beam resonance device and an accelerometer for electrostatic excitation detection, and adopts a cantilever beam structure with one end fixed and the other end free as a resonance unit. The vibration amplitude of the resonator is large, which improves the quality factor and frequency resolution of the sensor, reduces the difficulty of excitation detection, and facilitates subsequent structural parameter optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0018] Figure 1 It is a structural schematic diagram of a traditional double-end clamped beam;

[0019] Figure 2 A schematic diagram of the structure of a cantilever beam in a cantilever beam resonance device for electrostatic excitation detection according to a first embodiment of the present invention;

[0020] Figure 3 It is a schematic diagram of the overall appearance and hierarchical three-dimensional structure of the accelerometer according to the second embodiment of the present invention;

[0021] Figure 4 It is a schematic diagram of the internal cross-sectional hierarchical structure of the accelerometer according to the second embodiment of the present invention;

[0022] Figure 5 This is a schematic diagram of the internal three-dimensional structure of the accelerometer of Embodiment 2 of the present invention with half of the cover plate hidden;

[0023] Figure 6 This is a schematic diagram of the internal three-dimensional structure of the accelerometer of the second embodiment of the present invention after the entire cover plate is hidden;

[0024] Figure 7 It is a schematic diagram of the device cross-section obtained in steps S1 to S5 in the first manufacturing process of the accelerometer of the third embodiment of the present invention;

[0025] Figure 8 It is a schematic diagram of the device cross-section obtained in steps S6 to S8 in the first manufacturing process of the accelerometer of the third embodiment of the present invention;

[0026] Fig. 9 It is a schematic diagram of the device cross-section obtained in steps S9 to S11 in the first manufacturing process of the accelerometer of the third embodiment of the present invention;

[0027] Fig.10 Schematic diagram of device cross-section obtained in steps S12 to S14 in the first manufacturing process of the accelerometer of the third embodiment of the present invention;

[0028] Fig.11 It is a schematic diagram of the device cross-section obtained in steps S1' to S5' in the second manufacturing process of the accelerometer of the fourth embodiment of the present invention;

[0029] Fig.12 It is a schematic diagram of the device cross-section obtained in steps S6' to S8' in the second manufacturing process of the accelerometer of the fourth embodiment of the present invention;

[0030] Fig.13 It is a schematic diagram of the device cross-section obtained in steps S9' to S11' in the second manufacturing process of the accelerometer of the fourth embodiment of the present invention;

[0031] Fig.14 It is a schematic diagram of the device cross-section obtained in steps S12' to S14' in the second manufacturing process of the accelerometer of the fourth embodiment of the present invention;

[0032] Fig.15 It is a schematic diagram of the device cross-section obtained in steps S15' to S16' in the second manufacturing process of the accelerometer according to the fourth embodiment of the present invention;

[0033] Fig.16 It is a schematic diagram of the device cross-section obtained in step S17' in the second manufacturing process of the accelerometer according to the fourth embodiment of the present invention.

[0034] The figure numbers are as follows: 1 is a metal filling hole; 2 is a cover plate; 3 is an excitation unit; 4 is a device layer; 5 is a cantilever beam; 6 is a sacrificial layer; 7 is a base layer; 8 is a detection unit; 9 is a mass block; 10 is a metal electrode; 11 is a fixing unit; 12 is a connecting unit; 13 is a main body; 14 is a beam foot; and 15 is a supporting beam. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Embodiment 1

[0037] This embodiment 1 first provides a cantilever beam resonance device for electrostatic excitation detection, which is mainly composed of a cantilever beam 5 and a fixing unit 11, wherein one end of the cantilever beam 5 is fixedly connected to the fixing unit 11, which is the fixed end of the cantilever beam 5, and the other end is a free end. The fixed end of the cantilever beam 5 is also used to connect the acceleration sensitive mechanism.

[0038] This embodiment 2 also provides an accelerometer, which is mainly composed of the cantilever beam resonance device for electrostatic excitation detection, the cover plate 2, the device layer 4 and the base layer 7. The device layer 4 is vacuum-sealed between the cover plate 2 and the base layer 7, and the device layer 4 is provided with an acceleration sensitive mechanism; the acceleration sensitive mechanism is mainly composed of a mass block 9, a support beam 15 and a connecting unit 12; the mass block 9, the support beam 15, the connecting unit 12 and the cantilever beam 5 are suspended above the base layer 7; the support beam 15 is fixedly connected to the mass block 9, and is used to support the mass block 9 to be suspended in the air; the mass block 9 is connected to the fixed end of the cantilever beam 5 through the connecting unit 12.

[0039] External acceleration acts on the accelerometer, and the internal mass block 9 converts the acceleration information into stress information. The stress acting on the bottom fixed end of the cantilever beam 5 changes its axial equivalent stiffness and ultimately changes the output frequency signal of the cantilever beam 5. The frequency signal is picked up by the excitation detection unit 8 and the frequency change value is analyzed to calculate the external pressure.

[0040] The cantilever beam resonant accelerometer with electrostatic excitation detection using the cantilever beam 5 structure as the stress-frequency conversion unit has the following advantages: (1) One end of the cantilever beam 5 is fixed and the other end is free. Its fundamental frequency is lower than that of the double-end fixed beam, which is beneficial for application scenarios that require low-frequency response. (2) The boundary conditions of the cantilever beam 5 are relatively simple. One end is fixed and the other end is free. It is easy to analyze theoretically and verify experimentally, which is beneficial for subsequent design and optimization. (3) The displacement and vibration amplitude generated at the free end of the cantilever beam 5 are large, which makes it easier to excite and detect signals. (4) When the cantilever beam 5 is subjected to external excitation, the displacement of the free end is large, which enables the cantilever beam 5 to provide higher resolution. (5) The free end of the cantilever beam 5 is not constrained, and the damping effect in the air or liquid is small, which helps to maintain a high quality factor, thereby improving the performance of the resonator. (6) Because the cantilever beam 5 is in a form with one end fixed and the other end free, its geometric parameters such as length, width and thickness can be flexibly adjusted to change its resonant frequency and mechanical properties. This adjustability makes the accelerometer have higher design flexibility. The cantilever beam 5 itself is suspended in the air, with no constraint at one end, and the parameters can be freely changed according to the performance, that is, the length, width and other parameters of the cantilever beam can be adjusted according to actual needs. If the existing double-end clamped beam needs to increase the length of the beam, the overall size needs to be adjusted, such as increasing the size of the entire accelerometer device or reducing the mass block, which will change the performance of the accelerometer, thus affecting the overall parameter requirements of the final product.

[0041] In short, the cantilever beam resonance device and accelerometer for electrostatic excitation detection provided in this embodiment have large vibration amplitude of the resonator, are easy to excite and detect, have a high quality factor, and have good parameter adjustability.

[0042] Embodiment 2

[0043] Please refer to Figure 2 On the basis of the first embodiment, a more preferred embodiment is provided. The cantilever beam 5 in this embodiment is mainly composed of a main body 13 and two oppositely arranged beam feet 14 fixedly connected to the main body 13. There is a gap between the beam feet 14. The fixing unit 11 is fixedly connected to one of the beam feet 14, and the other of the beam feet 14 is used to connect the acceleration sensitive mechanism in the accelerometer. The top of the main body 13 is a free end, and the beam feet 14 are fixed ends. In a more preferred embodiment, the beam feet 14 are arranged on the main body 13 in parallel with each other, and the overall shape of the cantilever beam 5 is "n" shaped, which is called an n-type cantilever beam. The accelerometer of the present invention is a uniaxial accelerometer, which only senses horizontal forces. Therefore, the beam feet 14 are arranged to be parallel, so that stress can be better transferred along the direction of the force.

[0044] Please refer to Figures 3 to 6 Based on the accelerometer in Example 1, this embodiment provides a more preferred accelerometer, which is mainly different from the accelerometer in Example 1 in that its acceleration sensitive mechanism is also mainly composed of a mass block 9, a support beam 15 and a connecting unit 12, and the connecting unit 12 is connected to the other end of the beam foot 14 of the cantilever beam 5, that is, the two beam feet 14 of the cantilever beam 5 are respectively connected to the fixing unit 11 and the connecting unit 12. A plurality of support beams 15 can be provided. In this embodiment, Figure 6 As shown, four support beams 15 are provided, two by two are located at the upper and lower sides of the mass block 9, and are respectively embedded in the mass block 9 to achieve reliable support in a limited space.

[0045] When external acceleration acts on the accelerometer, the mass block 9 inside the accelerometer converts the acceleration into stress and transmits the signal through the connection unit 12. One of the beam legs 14 at the fixed end of the cantilever beam 5 is fixed by the fixing unit 11, and the other beam leg 14 receives the stress information transmitted by the mass block 9 through the connection unit 12. The external stress acts on the other beam leg 14 of the n-type cantilever beam 5, causing the structure of the n-type cantilever beam 5 to deform and change its axial equivalent stiffness, thereby changing the resonant frequency of the cantilever beam 5, and achieving the goal of converting stress information into a frequency signal.

[0046] Please refer to Figure 4The accelerometer of this embodiment is also provided with a sacrificial layer 6, which is located between the device layer 4 and the base layer 7. The fixing unit 11, the excitation unit 3 and the detection unit 8 are connected to the base layer 7 through the sacrificial layer 6. The mass block 9, the support beam 15, the connection unit 12 and the cantilever beam 5 are suspended by releasing the sacrificial layer 6. At the same time, the material of the key layer is provided, such as the cover plate 2 is made of glass, the base layer 7 and the device layer are both made of silicon, the sacrificial layer is made of SiO2, the device layer 4 is etched and released based on the SOI wafer, and after the cover plate 2 is cavity-etched, the device layer 4 is vacuum-encapsulated between the cover plate 2 and the base layer 7 by using the silicon-glass bonding process.

[0047] Please refer to Figure 4 In a more preferred embodiment, a signal lead-out structure is designed, specifically: a metal-filled hole 1 is provided on the cover plate 2, the metal-filled hole 1 leads to the device layer 4, and a metal material is filled in the metal-filled hole 1 to lead out the signal of the device layer 4. The metal-filled hole 1 can be obtained by etching through TSV silicon through hole technology or TGV glass through hole technology. At the same time, in order to ensure the reliability of the connection between the metal material filled in the metal-filled hole 1 and the device layer 4, a metal electrode 10 is provided between the metal-filled hole 1 and the device layer 4. Since the device layer 4 is made of silicon, and silicon is relatively hard, it is not easy to connect directly with the metal material above, so a metal electrode 10 is added, one side of the metal electrode 10 is connected to the metal material in the metal-filled hole 1, and the other side is connected to the device layer 4. The contact area of ​​the connection is increased by the metal electrode 10 to achieve a more stable connection. The metal electrode 10 is preferably made of Au material, mainly for the following considerations and advantages: the contact resistance between gold and many materials is relatively low, which can achieve better electrical connection and improve the performance of the device. Gold is relatively soft and has good connectivity with other materials. The metal material filled in the metal-filled hole 1 is preferably made of Cu copper, mainly for the following considerations and advantages: 1. Matching of thermal expansion coefficients: The thermal expansion coefficients of glass and copper are similar, so when the temperature changes, copper can better maintain consistent thermal expansion with the glass, reducing the impact of thermal stress on the structure. 2. Conductive properties: Copper is an excellent conductive material with good electrical conductivity and low resistivity. In MEMS, through holes are often used to connect conductive lines, so filling copper can provide good electrical properties and ensure the quality of signal transmission. 3. Cost and process advantages: Copper is a common metal material with a wide range of applications and low cost. At the same time, the copper filling process is relatively simple and can be achieved through methods such as electroplating, which has good compatibility with the MEMS manufacturing process.

[0048] The n-type cantilever beam 5 is connected to a DC voltage to generate charges on the surface of the resonant beam. The excitation unit 3 is connected to a DC plus AC voltage to form an excitation capacitor with the n-type cantilever beam 5. The n-type resonant beam 5 enters a resonant state through the alternating Coulomb force generated by the excitation capacitor. The detection unit 8 is connected to a DC voltage to form a detection capacitor with the horizontally vibrating n-type cantilever beam 5, and converts the displacement information of the resonant beam into capacitance information and sequentially outputs it through the metal electrode 10 and the metal filling hole 1. By analyzing the output signal, the resonant frequency of the resonant beam is measured, and then the acceleration of the environment in which the accelerometer is located is calculated.

[0049] Embodiment 3

[0050] This embodiment further provides a specific method for suspending the device layer 4, and the sacrificial layer is released by opening a release hole process on the front side, as shown in steps S7 to S13. In conjunction with the accompanying drawings, the first manufacturing process of the accelerometer of the present invention is provided, which includes the process of releasing the sacrificial layer. The first manufacturing process will be described in detail below. For the purpose of exemplary description, specific dimensions and materials are provided, but they should not be regarded as limiting the scope of protection of the present invention, and the materials and dimensions are not limited thereto.

[0051] The first manufacturing process of accelerometer, please refer to Figures 7 to 10 :

[0052] S1 cover plate spare: six-inch or four-inch glass plate, cleaned.

[0053] S2 signal lead-out structure fabrication: TGV glass through hole, filled with Cu as the signal lead-out structure.

[0054] S3 bonding electrode production: spin coating photoresist, patterning, sputtering Au, as a bonding electrode, which can be bonded with the metal electrode 10.

[0055] S4 one-step debonding: stripping Au spin-coated photoresist and patterning.

[0056] S5 etching and secondary degumming: etching the cavity structure of the upper glass cover plate and degumming.

[0057] S6 substrate and device layer preparation wafer: six-inch or four-inch double-polished SOI wafer (top silicon is highly doped, bottom silicon is low doped), cleaned.

[0058] S7 one-step patterning coating: spin coating photoresist, patterning.

[0059] S8 metal sputtering: sputtering Au, thickness 200nm.

[0060] S9 three times of degumming: degumming to complete the production of Au electrode (metal electrode 10).

[0061] S10 secondary patterning coating: spin coating photoresist, patterning.

[0062] S11 device layer etching: etching the device layer structure.

[0063] S12 four times of degumming.

[0064] S13 device layer release: Use HF (hydrofluoric acid) to etch the sacrificial layer and release the device layer structure (for the parts with a single side larger than 15um but need to be released, release hole etching is performed to assist release).

[0065] S14, bonding cover plate: bonding the glass cover plate to complete the overall structure.

[0066] Embodiment 4

[0067] This embodiment further provides a specific method for suspending the device layer 4, and the sacrificial layer is released by engraving the back substrate layer, as shown in steps S7' to S16'. In conjunction with the accompanying drawings, a second manufacturing process of the accelerometer of the present invention is provided, which includes the process of releasing the sacrificial layer. The second manufacturing process will be described in detail below. For the purpose of exemplary description, specific dimensions and materials are provided, but they should not be regarded as limiting the scope of protection of the present invention, and the materials and dimensions are not limited thereto.

[0068] The second manufacturing process of accelerometer, please refer to Figures 11 to 16 :

[0069] S1' Cover plate preparation: six-inch or four-inch glass plate, cleaned.

[0070] S2' signal lead-out structure fabrication: TGV glass through hole, filled with Cu as the signal lead-out structure.

[0071] S3 ′ bonding electrode fabrication: spin coating photoresist, patterning, and sputtering Au as a bonding electrode that can be bonded to the metal electrode 10 .

[0072] S4' one-step stripping: stripping off Au spin-coated photoresist and patterning.

[0073] S5' etching and secondary debonding: etching the cavity structure of the upper glass cover plate and debonding.

[0074] S6' Base layer and device layer preparation: six-inch or four-inch double-polished SOI wafer (top silicon is highly doped, bottom silicon is low doped), cleaned.

[0075] S7' back cavity etching mask preparation: grow SiO2 on the back side as the back cavity etching mask.

[0076] S8' Patterning of back-coating and etching: Spin-coat photoresist on the back, patterning, and etching SiO2.

[0077] S9' three times of stripping and etching: stripping, etching the back cavity to SiO2.

[0078] S10' Patterning coating: Spin coating photoresist, patterning.

[0079] S11' Metal sputtering: sputtering Au, thickness 200nm.

[0080] S12' Fourth stripping: stripping to complete the production of the Au electrode (metal electrode 10).

[0081] S13' Secondary patterning coating: spin coating photoresist, patterning.

[0082] S14' device layer etching: etching the device layer structure.

[0083] S15' five times of degumming.

[0084] S16' device layer release: HF is used to etch the sacrificial layer to release the device layer structure.

[0085] S17' Bonding cover plate: Bond the upper and lower glass cover plates to complete the overall structure.

[0086] Compared with the second process of Example 4, Example 3 uses the first manufacturing process to manufacture the accelerometer of the present invention. The manufacturing process is relatively simple and has certain advantages in production cost and production efficiency. Compared with the first process, the second process of Example 4 has more process steps and more complicated processes, but the release from the back cavity can release the silicon dioxide at the bottom of the device layer more cleanly, and will not cause the device layer to adhere to the bottom. And the back release does not require the release hole structure on the front, and the factors that need to be considered in the structural design can be reduced. Therefore, in terms of product structure design and product quality.

[0087] Based on the above embodiments, the present invention realizes stress-frequency conversion through a cantilever beam resonance device and an accelerometer for electrostatic excitation detection, wherein the resonance device is composed of a cantilever beam and a fixing unit. The excitation unit and the detection unit fixed on the silicon dioxide layer respectively form an excitation capacitor and a detection capacitor with the cantilever beam to form an excitation detection structure for driving the resonant structure to resonate and detect the output signal. This embodiment uses a cantilever beam structure as a resonance unit, which improves the quality factor and frequency resolution of the sensor, reduces the difficulty of excitation detection, and facilitates subsequent structural parameter optimization. In this embodiment, the device layer 4 is completed by one-time etching of SOI, and then vacuum packaging is completed by silicon-glass bonding. The process is simple, and there is no very fine structure inside. The process compatibility is good, the error tolerance is high, and it has good application value.

[0088] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0089] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present invention. It should be pointed out that, for those skilled in the art, several deformations and improvements can be made without departing from the concept of the present invention. The n-type cantilever beam resonant device proposed in the accelerometer of the above-mentioned embodiment should include structures formed by simple deformation thereof without changing its stress transfer mechanism, which all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A cantilever beam resonance device for electrostatic excitation detection, comprising an excitation detection mechanism and a resonance mechanism; the resonance mechanism comprises a cantilever beam (5) and a fixing unit (11); the excitation detection mechanism comprises an excitation unit (3) and a detection unit (8) respectively located on both sides of the cantilever beam (5); characterized in that: One end of the cantilever beam (5) is fixedly connected to the fixing unit (11) and is the fixed end of the cantilever beam (5), and the other end is a free end.

2. The cantilever beam resonance device for electrostatic excitation detection according to claim 1, characterized in that: The cantilever beam (5) comprises a main body (13) and two beam feet (14) which are arranged opposite to each other and are fixedly connected to the main body (13); a gap is provided between the beam feet (14); the fixing unit (11) is fixedly connected to one of the beam feet (14); the top end of the main body (13) is the free end, and the beam feet (14) are the fixed ends.

3. The cantilever beam resonance device for electrostatic excitation detection according to claim 2, characterized in that: The beam feet (14) are arranged on the body (13) in parallel with each other.

4. An accelerometer, comprising the cantilever beam resonance device for electrostatic excitation detection according to any one of claims 1 to 3, characterized in that: It also comprises a cover plate (2), a device layer (4) and a base layer (7), wherein the device layer (4) is vacuum-sealed between the cover plate (2) and the base layer (7), and the device layer (4) comprises an acceleration sensitive mechanism; The acceleration sensitive mechanism comprises a mass block (9), a support beam (15) and a connection unit (12); the mass block (9), the support beam (15), the connection unit (12) and the cantilever beam (5) are suspended above the base layer (7); The support beam (15) is fixedly connected to the mass block (9) and is used to support the mass block (9) to be suspended in the air; the mass block (9) is connected to the fixed end of the cantilever beam (5) through the connection unit (12).

5. The accelerometer according to claim 4, characterized in that: It also includes a sacrificial layer (6) located between the device layer (4) and the base layer (7); the fixing unit (11), the excitation unit (3) and the detection unit (8) are connected to the base layer (7) via the sacrificial layer (6); and the mass block (9), the support beam (15), the connection unit (12) and the cantilever beam (5) are suspended by releasing the sacrificial layer (6).

6. The accelerometer according to claim 5, characterized in that: The sacrificial layer (6) is released for suspension treatment by opening a release hole on the front side to release the sacrificial layer and / or by engraving the back side base layer to release the sacrificial layer.

7. The accelerometer according to claim 4, characterized in that: The cover plate (2) is provided with a metal filling hole (1), the metal filling hole (1) leads to the device layer (4), the metal filling hole (1) is filled with a metal material for leading out a signal of the device layer (4), and the metal filling hole (1) is obtained by etching through the TSV silicon via technology or the TGV glass via technology.

8. The accelerometer according to claim 7, characterized in that: A metal electrode (10) is provided between the metal filling hole (1) and the device layer (4); one side of the metal electrode (10) is connected to the metal material in the metal filling hole (1), and the other side is connected to the device layer (4).

9. The accelerometer according to claim 4, characterized in that: The device layer (4) is etched and released based on an SOI wafer, the cover plate (2) is made of glass, the base layer (7) is made of silicon, and after cavity etching of the cover plate (2), the device layer (4) is vacuum-sealed between the cover plate (2) and the base layer (7) using a silicon-glass bonding process.

10. The accelerometer according to claim 4, characterized in that: The accelerometer is manufactured by the first process or the second process; the first process includes the following steps: preparing a cover plate, manufacturing a signal lead-out structure, manufacturing bonding electrodes, primary degumming, etching and secondary degumming, preparing a base layer and a device layer, primary patterning, metal sputtering, tertiary degumming, secondary patterning, device layer etching, fourth degumming, device layer release and bonding the cover plate; the second process includes the following steps: preparing a cover plate, manufacturing a signal lead-out structure, manufacturing bonding electrodes, primary degumming, etching and secondary degumming, preparing a base layer and a device layer, manufacturing a back cavity etching mask, patterning back glue coating and etching, tertiary degumming and etching, patterning, metal sputtering, fourth degumming, secondary patterning, device layer etching, fifth degumming, device layer release and bonding the cover plate.

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