An internal resonance coupled electromagnetic induction micromechanical magnetic sensor and its preparation method

Abstract

The present invention discloses an electromagnetic induction micro-machined magnetic sensor with internal resonance coupling and a preparation method. The electromagnetic induction micro-machined magnetic sensor comprises a first resonant structure, a second resonant structure, and a coupling beam between the two resonant structures. The present invention connects two resonant structures with an integer ratio of resonant frequencies via the coupling beam to form an internal resonance coupling resonant system. The system can transfer overloaded nonlinear energy to the other resonant structure through the internal resonance principle after a resonant structure reaches resonant nonlinearity, causing it to resonate. Thus, the performance of the magnetic sensor is improved by superimposing the electromagnetic induction magnetic signals output by the two resonant structures, overcoming the limitation of traditional electromagnetic induction magnetic sensors with a single resonant structure that it is difficult to improve device performance by increasing the overload of the electrostatic driving force.

Description

Technical Field

[0001] The present invention relates to a magnetic sensor and a preparation method thereof, and in particular to an internal resonance coupled electromagnetic induction micro-mechanical magnetic sensor and a preparation method thereof. Background Art

[0002] Magnetic field sensors are common sensing devices in everyday life. They utilize various physical principles to convert magnetic signals into electrical output signals and have widespread applications in consumer, industrial, and military applications. Since their inception, magnetic sensors have garnered widespread attention within the industry due to their excellent stability, anti-interference capabilities, and contactless measurement capabilities. Since the 1990s, the development of microelectronics and mechanical systems has enabled new advancements in magnetic field sensors. On the one hand, magnetic field sensors have become increasingly miniaturized, and on the other hand, the advancement of MEMS technology has solved the problem of measuring magnetic fields at microscales. Micromachining has also enabled the development of some micromechanical magnetic field sensors, such as MEMS magnetic sensors that utilize the Lorentz force of magnetic fields. Lorentz-force-based magnetic field sensors apply an alternating current at the same frequency as the resonant structure to a coil. This current, in the presence of an external magnetic field, is subjected to the Lorentz force, causing the resonant structure to resonate. The magnitude of the measured magnetic field is then determined using capacitive or piezoresistive detection methods. Lorentz-force-based magnetic field sensors offer advantages such as small size, light weight, low cost, and the absence of hysteresis and magnetic saturation, making them promising candidates for development in the sensor market. However, to achieve higher sensitivity, the current in the coil must be increased, which increases the device's power consumption. Furthermore, increased power consumption leads to higher temperatures, which affects device stability. Furthermore, the device exhibits significant nonlinearity under large displacements.

[0003] To address the aforementioned issues with Lorentz force magnetic sensors, a new type of MEMS magnetic field sensor based on electromagnetic induction has recently been proposed. When operating, this device generates a change in the magnetic flux passing through a closed coil. According to the law of electromagnetic induction, an induced electromotive force (EMF) is generated at both ends of the coil, proportional to the measured magnetic field. By detecting this induced EMF, the magnitude of the measured magnetic field can be determined. In addition to the advantages of Lorentz force sensors, this type of sensor also offers low power consumption, good linearity, and simple detection circuit design.

[0004] The functionality of electromagnetic induction magnetic field sensors relies on a resonant structure, but existing electromagnetic induction magnetic field sensor resonant structures are all single resonant structures. For example, the invention application with application publication number CN106443525A discloses a torsional micromechanical magnetic field sensor and its preparation method. Because the driving force and amplitude of the resonant structure are linearly proportional at low amplitudes, but nonlinearity occurs at large amplitudes, when the magnetic field sensor performance is further improved by increasing the electrostatic driving force, the traditional electromagnetic induction magnetic sensor will easily enter a resonant nonlinear amplitude saturation state due to its single resonator. Therefore, in this case, the electromagnetic induction magnetic field sensor cannot further improve its performance by increasing the driving force. Summary of the Invention

[0005] The present invention aims to overcome the above-mentioned problems and provides an internally resonant coupled electromagnetic induction micromachined magnetic sensor. The micromachined magnetic sensor connects two resonant structures with an integer ratio of resonant frequencies (frequency ratio greater than or equal to 2:1) through a coupling beam to form an internally resonant coupled resonant system. After one resonant structure reaches resonant nonlinearity, the system can transfer the overloaded nonlinear energy to the other resonant structure through the internal resonance principle to cause it to resonate. This improves the performance of the magnetic sensor by superimposing the electromagnetic induction magnetic field sensing signal outputs of the two resonant structures, overcoming the limitation of traditional single resonant structure electromagnetic induction magnetic sensors that are difficult to improve device performance by increasing the overload of electrostatic driving force.

[0006] Another object of the present invention is to provide a method for preparing an internal resonant coupled electromagnetic induction micromechanical magnetic sensor.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] An internal resonant coupled electromagnetic induction micro-mechanical magnetic sensor comprises a first resonant structure component, a second resonant structure component and a coupling beam between the two resonant structures;

[0009] The first resonant structure component includes a driving electrode, a first resonant structure, a first silicon body insulating layer, a first induction coil, a first coil insulating layer, and a first coil metal layer; the first silicon body insulating layer is disposed on the first resonant structure; the driving electrode is located on a side of the first resonant structure away from the first silicon body insulating layer; the first induction coil is disposed on the first silicon body insulating layer; the first coil insulating layer is disposed on the first induction coil; and the first coil metal layer is disposed on the first coil insulating layer;

[0010] The second resonant structure component includes a second resonant structure, a second silicon body insulating layer, a second induction coil, a second coil insulating layer, and a second coil metal layer; the second silicon body insulating layer is disposed on the second resonant structure; the second induction coil is disposed on the second silicon body insulating layer; the second coil insulating layer is disposed on the second induction coil; and the second coil metal layer is disposed on the second coil insulating layer;

[0011] In a working state, the driving electrode drives the first resonant structure into a torsional or translational resonant mode by electrostatic drive. When the first resonant structure is in the torsional or translational resonant mode, the first induction coil cuts the magnetic flux lines in an external magnetic field, generating an induced electromotive force signal proportional to the magnitude of the external magnetic field. When the applied driving voltage causes the first resonant structure to approach a critical point of a nonlinear state, if the electrostatic driving voltage is further increased to increase the driving force, the first resonant structure enters a nonlinear amplitude saturation state.

[0012] Based on the principle of internal resonance, the nonlinear resonant energy on the overload-driven first resonant structure is transferred to the second resonant structure through a coupling beam, driving the second resonant structure to perform torsional or translational resonant motion. The second induction coil cuts the magnetic flux lines and generates a new induced electromotive force signal. The two output electromotive force signals are processed and converted into DC signals respectively, and then the two DC signals are summed to reflect the strength of the magnetic field.

[0013] The working principle of the above-mentioned internal resonant coupled electromagnetic induction micromechanical magnetic sensor is as follows:

[0014] During operation, the first resonant structure is electrostatically driven by applying an AC drive voltage at the same frequency as the first resonant structure, causing it to undergo resonant motion. When the first resonant structure is in a torsional or translational resonant mode, the first induction coil of the first resonant structure cuts the magnetic flux lines, generating an induced electromotive force signal proportional to the magnitude of the external magnetic field. Furthermore, when the applied drive voltage causes the first resonant structure to approach the critical point of the nonlinear state, further increasing the electrostatic drive voltage to increase the driving force causes the first resonant structure to enter a nonlinear amplitude saturation state. Based on the principle of internal resonance, the nonlinear energy of the overloaded first resonant structure can be transferred to the second resonant structure through internal resonance, thereby driving the second resonant structure to undergo torsional or translational resonant motion. The second induction coil of the second resonant structure also cuts the magnetic flux lines, generating a new induced electromotive force signal. By processing the two output electromotive force signals separately and converting them into DC signals, the two DC signals are summed to reflect the magnetic induction intensity of the surrounding magnetic field, thereby improving the performance of the magnetic sensor.

[0015] In a preferred embodiment of the present invention, the ratio of the torsional (or translational) resonant mode frequency of the first resonant structure to the torsional (or translational) resonant mode frequency of the second resonant structure is an integer multiple and the high-to-low frequency ratio is greater than or equal to 2:1.

[0016] In a preferred embodiment of the present invention, the first resonant structure adopts a low-frequency structure, and the second resonant structure adopts a high-frequency structure; or the first resonant structure adopts a high-frequency structure, and the second resonant structure adopts a low-frequency structure.

[0017] Furthermore, the vibration modes corresponding to the resonant modes of the first resonant structure and the second resonant structure are the same, and are both torsional resonant modes or both in-plane translational modes;

[0018] If it is a torsional mode, the driving electrode and the sensing electrode should be respectively arranged between the first resonant structure and the substrate sheet, and between the second resonant structure and the substrate sheet;

[0019] If it is an in-plane translational mode, the driving electrodes and the sensing electrodes are arranged at any position suitable for driving and detecting the translational mode of the structure around the first resonant structure and the second resonant structure.

[0020] In a preferred embodiment of the present invention, the first resonant structure assembly and the second resonant structure assembly each further include an anchor point and a support beam;

[0021] The anchor point is provided on the substrate;

[0022] One end of the support beam is fixedly connected to the anchor point, and the other end of the support beam is fixedly connected to the first resonant structure or the second resonant structure.

[0023] In a preferred embodiment of the present invention, the first induction coil and the second induction coil form at least one layer; and the number of turns of the first induction coil and the second induction coil in each layer is at least one turn.

[0024] Furthermore, when the first induction coil is multi-layered, an isolation insulating layer is provided between two adjacent layers of the first induction coil; when the second induction coil is multi-layered, an isolation insulating layer is provided between two adjacent layers of the second induction coil;

[0025] When the first induction coil has multiple turns, the winding direction of each turn of the first induction coil is the same; when the second induction coil has multiple turns, the winding direction of each turn of the second induction coil is the same.

[0026] In a preferred embodiment of the present invention, the first resonant structure component and the second resonant structure component each further include at least two pads.

[0027] The two pads are respectively connected to two ends of the first induction coil or two ends of the second induction coil.

[0028] A preferred embodiment of the present invention is that the resonant motion mode of the first resonant structure and the second resonant structure can be set according to the direction of the required measurement magnetic field, which can be a torsional motion suitable for in-plane magnetic field measurement as exemplified in this embodiment, or a resonant structure translational motion suitable for out-of-plane magnetic field measurement, as well as other motion modes.

[0029] A method for preparing an internal resonant coupled electromagnetic induction micromechanical magnetic sensor comprises the following steps:

[0030] (1) preparing a device silicon wafer and forming a cavity structure on the surface of the device silicon wafer by photolithography and etching processes;

[0031] (2) preparing a substrate sheet and forming a substrate insulating layer on the surface of the substrate sheet;

[0032] (3) depositing a driving electrode metal layer on the surface of the insulating layer at the substrate, and forming the driving electrode and the substrate metal layer by photolithography and etching processes;

[0033] (4) performing face-to-face eutectic bonding of the metal dielectric layer on the cavity pattern side of the device silicon wafer and the electrode pattern side of the substrate wafer;

[0034] (5) Thinning the device silicon wafer by etching;

[0035] (6) depositing an insulating layer on the surface of the device silicon wafer, and forming a first silicon body insulating layer and a second silicon body insulating layer by photolithography and etching processes;

[0036] (7) forming a first induction coil and a second induction coil on the surfaces of the first silicon body insulating layer and the second silicon body insulating layer respectively by deposition and etching processes;

[0037] (8) depositing an insulating layer on the surface of the first induction coil and the second induction coil, and forming a first coil insulating layer and a second coil insulating layer respectively by photolithography and etching processes;

[0038] (9) depositing a metal layer on the first coil insulation layer and the second coil insulation layer, and forming a first coil metal layer and a second coil metal layer by etching;

[0039] (10) Etching the device silicon wafer to form a coupling beam to connect the internal resonance coupling resonant structure of the two resonant structures.

[0040] In a preferred embodiment of the present invention, in step (2), before forming the insulating layer at the substrate, alignment marks are photoetched on the back side of the substrate using a forward and reverse alignment photolithography method.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The micromechanical magnetic sensor of the present invention connects two resonant structures with an integer ratio of resonant frequencies (frequency ratio greater than or equal to 2:1) through a coupling beam to form an internally resonant coupled resonant system. This system can transfer the overloaded nonlinear energy to the other resonant structure through the internal resonance principle after one resonant structure reaches resonant nonlinearity, causing it to resonate. This improves the performance of the magnetic sensor by superimposing the electromagnetic induction magnetic field sensing signals output by the two resonant structures, overcoming the limitation of traditional electromagnetic induction magnetic sensors with a single resonant structure that it is difficult to improve device performance by increasing the overload of the electrostatic driving force. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a working flow diagram of the internal resonant coupled electromagnetic induction micromechanical magnetic sensor of the present invention.

[0044] Figure 2 This is a schematic diagram of the working principle of the first embodiment of the internal resonant coupled electromagnetic induction micromechanical magnetic sensor of the present invention.

[0045] Figure 3 1 is a schematic top view of the structure of a second embodiment of the internal resonant coupled electromagnetic induction micromechanical magnetic sensor of the present invention.

[0046] Figure 4-13 It is a schematic diagram of the cross-sectional structure of each step in the method for preparing the internal resonance coupled electromagnetic induction type micro-mechanical magnetic sensor of the present invention.

[0047] Description of labels

[0048] 1. The first resonant structure at the device silicon wafer

[0049] 2. Second resonant structure at the device silicon wafer

[0050] 111. Insulating layer at substrate

[0051] 112. First silicon body insulating layer

[0052] 113. Second silicon body insulation layer

[0053] 114. First coil insulation layer

[0054] 115. Second coil insulation layer

[0055] 121. First induction coil

[0056] 122. Second induction coil

[0057] 13. Anchor

[0058] 15. Support beam

[0059] 16. Metal layer at substrate

[0060] 161. Bonding metal layer

[0061] 162. Driving Electrode

[0062] 17. First coil metal layer

[0063] 18. Second coil metal layer

[0064] 19. Solder pad

[0065] 20. Coupled beam

[0066] 21. Substrate

[0067] 22. Structural pieces

[0068] 221. Cavity Structure

[0069] 30. Alignment marks on the substrate DETAILED DESCRIPTION

[0070] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0071] Example 1

[0072] See also Figure 2 The internal resonant coupled electromagnetic induction micromechanical magnetic sensor of this embodiment is suitable for detecting a unidirectional magnetic field in a plane, and includes a first resonant structural component and a second resonant structural component coupled by a coupling beam 20, and the two resonant structural components are connected by the coupling beam 20 to form an internal resonant coupled resonant system.

[0073] See also Figure 2 The first resonant structure component includes: a first resonant structure 1, a first silicon body insulation layer 112, a first coil insulation layer 114, a first coil metal layer 17, a first induction coil 121, and a driving electrode 162; the first silicon body insulation layer 112 is located on the surface of the first resonant structure 1; the first induction coil 121 is located on the surface of the first silicon body insulation layer 112; the first coil insulation layer 114 is located on the surface of the first induction coil 121; the first coil metal layer 17 is located on the surface of the first coil insulation layer 114; the driving electrode 162 is suitable for driving the first resonant structure 1 in an electrostatic driving manner, so that the first resonant structure 1 is in a torsional or translational resonant mode.

[0074] See also Figure 2The second resonant structure component includes: a second resonant structure 2, a second silicon body insulation layer 113, a second coil insulation layer 115, a second coil metal layer 18, and a second induction coil 122; the second silicon body insulation layer 113 is located on the surface of the second resonant structure 2; the second induction coil 122 is located on the surface of the second silicon body insulation layer 113; the second coil insulation layer 115 is located on the surface of the second induction coil 122; and the second coil metal layer 18 is located on the surface of the second coil insulation layer 115.

[0075] Specifically, the ratio of the torsional (or translational) resonance modal frequency of the first resonant structure 1 to the torsional (or translational) resonance modal frequency of the second resonant structure 2 is greater than or equal to 2:1, and the integer multiple relationship between the two can be set according to actual needs.

[0076] Furthermore, the first resonant structure 1 and the second resonant structure 2 can adopt high frequency, low frequency or low frequency and high frequency. In this embodiment, the first resonant structure 1 adopts a low frequency structure and the second resonant structure 2 adopts a high frequency structure.

[0077] Furthermore, the shapes of the first resonant structure 1 and the second resonant structure 2 can be set according to actual needs. In this embodiment, the shapes of the first resonant structure 1 and the second resonant structure 2 are both rectangular plate structures.

[0078] See also Figure 2 The first resonant structure component and the second resonant structure component also include an anchor point 13 and a support beam 15; the anchor point 13 is located on the surface of the substrate 21; the first resonant structure 1 and the second resonant structure 2 are both separated from the anchor point 13 and the surface of the substrate 21 by a certain distance; one end of the support beam 15 is fixedly connected to the anchor point 13, and the other end is fixedly connected to the first resonant structure 1 or the second resonant structure 2.

[0079] Furthermore, the number of the anchor points 13 and the support beams 15 can be set according to actual needs. In this embodiment, in the first resonant structure 1 and the second resonant structure 2, the number of the anchor points 13 and the support beams 15 are both two, and are symmetrically distributed on both sides of the first resonant structure 1 and the second resonant structure 2.

[0080] See also Figure 2 A substrate insulating layer 111 is further provided between the substrate 21 and the driving electrode 162 . The substrate insulating layer 111 is located on the surface of the substrate 21 , and the driving electrode 162 is located on the surface of the substrate insulating layer 111 .

[0081] See also Figure 2The driving electrode 162 is located between the first resonant structure 1 and the substrate 21 and on the surface of the substrate 21. The number of the driving electrodes 162 can be set according to actual needs. In this embodiment, the number of the driving electrodes 162 is one or more; in this embodiment, the number is two.

[0082] Specifically, the first induction coil 121 and the second induction coil 122 form at least one layer, and each layer of the first induction coil 121 and the second induction coil 122 has at least one turn. If the induction coils are multi-layered and multi-turn, the multi-turn induction coils in each layer have the same winding direction, and an insulating layer (not shown) is provided between the induction coils in each layer to isolate adjacent induction coils.

[0083] The number of coil layers, the number of turns, and the winding direction of the first induction coil 121 and the second induction coil 122 can be set according to actual needs.

[0084] See also Figure 2 The first resonant structure component and the second resonant structure component further include a pad 19. The number of the pads 19 can be set according to actual needs. In this embodiment, there are two pads 19, one of which is connected to one end of the first induction coil 121 and the second induction coil 122, and the other pad 19 is connected to the other end of the above-mentioned induction coil.

[0085] See also Figure 1 and Figure 13 The working principle of the internal resonant coupled electromagnetic induction micro-machined magnetic sensor of this embodiment is as follows:

[0086] In an internally resonant coupled resonant system consisting of two resonant structures coupled by a coupling beam 20, an AC drive voltage at the same frequency as the first resonant structure 1 is applied to electrostatically drive the first resonant structure 1, causing it to undergo resonant motion. When the first resonant structure 1 is in a torsional or translational resonant mode, the first induction coil 121 at the first resonant structure cuts the magnetic flux lines, thereby generating an induced electromotive force signal proportional to the magnitude of the external magnetic field. When the applied drive voltage causes the first resonant structure 1 to reach a critical point in the nonlinear state, if the drive voltage is further increased to further increase the driving force, a conventional electromagnetic induction magnetic sensor, due to its single resonator, will easily enter a state of amplitude saturation due to the resonant nonlinearity. However, the magnetic field sensor structure described in the present invention has two resonant structures and can transfer the resonant nonlinear energy of the overloaded resonant structure to the second resonant structure 2 through internal resonance, thereby driving the second resonant structure 2 to undergo resonant motion. The second induction coil 122 at the second resonant structure also cuts the magnetic flux lines, thereby generating a new induced electromotive force signal. The two output electromotive force signals are processed separately to convert them into DC signals, and then the two DC signals are added together to reflect the strength of the magnetic field.

[0087] Example 2

[0088] See also Figure 3 , which is different from Example 1, the first resonant structure 1 of this embodiment adopts a high-frequency structure, and the second resonant structure 2 adopts a low-frequency structure.

[0089] Example 3

[0090] See also Figures 4 to 13 The method for preparing the internal resonant coupled electromagnetic induction micro-mechanical magnetic sensor of this embodiment includes the following steps:

[0091] (1) See Figure 4 A silicon wafer is provided as a structural wafer 22, a cavity pattern is defined by photolithography, and a cavity structure 221 is etched in the structural wafer 22 using deep reactive ion etching technology.

[0092] (2) See Figure 5 , prepare a silicon substrate 21 (can be but not limited to Si substrate), and use the front and back alignment photolithography method to lithography alignment marks 30 on the back side of the silicon substrate 21.

[0093] (3) See Figure 6Thermal oxidation or chemical vapor deposition (e.g., low-pressure chemical vapor deposition (LPCVD)) is used to form an insulating thin film, such as a silicon oxide film, on the upper surface of the silicon substrate 21. Then, photolithography and reactive ion etching are performed to form the substrate insulating layer 111 region. Physical vapor deposition, such as sputtering, is used to deposit a layer of drive electrode material, such as a gold layer, on the surface of the substrate insulating layer 111. Photolithography and reactive ion etching are then performed to form the drive electrode material layer to form the drive electrode 162 region and the substrate metal layer 16 region. Specifically, the number of drive electrodes 162 can be one, or two as in this embodiment, but is not limited to two.

[0094] (4) See Figure 7 The cavity pattern side of the structural sheet 22 and the electrode pattern side of the substrate sheet 21 are face to face and the wafer metal dielectric layer is aligned and bonded, such as using gold-silicon eutectic bonding; the metal layer 16 at the substrate is transformed into a metal bonding layer 161.

[0095] (5) See Figure 8 The structural sheet 22 is thinned by chemical mechanical polishing or wet etching such as KOH etching process.

[0096] (6) See Figure 9 An insulating layer film such as a silicon oxide film is deposited on the structural piece 22 using plasma enhanced chemical vapor deposition (PECVD) technology, and then the insulating layer pattern is defined by photolithography, and the insulating layer is etched using reactive ion etching technology to form a first silicon body insulating layer 112 region and a second silicon body insulating layer 113 region.

[0097] (7) See Figure 10 A metal layer such as an aluminum layer is formed on the surface of the first silicon body insulating layer 112 and the second silicon body insulating layer 113 by physical vapor deposition such as sputtering, and then a first induction coil 121 and a second induction coil 122 are formed respectively by a plasma etching process.

[0098] (8) See Figure 11 An insulating layer film, such as a silicon oxide film, is deposited on the first induction coil 121 and the second induction coil 122 using plasma enhanced chemical vapor deposition (PECVD) technology. Subsequently, the insulating layer pattern is defined by photolithography, and the insulating layer is etched using reactive ion etching technology to form a first coil insulating layer 114 region and a second coil insulating layer 115 region.

[0099] (9) See Figure 12 A metal layer such as an aluminum layer is formed on the surface of the first coil insulation layer 114 and the second coil insulation layer 115 by chemical vapor deposition or physical vapor deposition, and a first coil metal layer 17 region and a second coil metal layer 18 region are formed by reactive ion etching.

[0100] (10) See Figure 13 A deep reactive ion etching process is used on the structure sheet 22 to etch and release to form the first resonant structure 1 and the second resonant structure 2.

[0101] Furthermore, the support beam 15 is formed by etching while forming the first resonant structure 1 and the second resonant structure 2 .

[0102] The above is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited to the above content. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. An internal resonant coupled electromagnetic induction micromechanical magnetic sensor, characterized in that: The invention comprises a first resonant structural component, a second resonant structural component and a coupling beam coupled between the first resonant structural component and the second resonant structural component; The first resonant structure component includes a driving electrode, a first resonant structure, a first silicon body insulating layer, a first induction coil, a first coil insulating layer, and a first coil metal layer; the first silicon body insulating layer is disposed on the first resonant structure; the driving electrode is located on a side of the first resonant structure away from the first silicon body insulating layer; the first induction coil is disposed on the first silicon body insulating layer; the first coil insulating layer is disposed on the first induction coil; and the first coil metal layer is disposed on the first coil insulating layer; The second resonant structure component includes a second resonant structure, a second silicon body insulating layer, a second induction coil, a second coil insulating layer, and a second coil metal layer; the second silicon body insulating layer is disposed on the second resonant structure; the second induction coil is disposed on the second silicon body insulating layer; the second coil insulating layer is disposed on the second induction coil; and the second coil metal layer is disposed on the second coil insulating layer; In a working state, the driving electrode drives the first resonant structure into a torsional or translational resonant mode by electrostatic drive. When the first resonant structure is in the torsional or translational resonant mode, the first induction coil cuts the magnetic flux lines in an external magnetic field, generating an induced electromotive force signal proportional to the magnitude of the external magnetic field. When the applied driving voltage causes the first resonant structure to approach a critical point of a nonlinear state, if the electrostatic driving voltage is further increased to increase the driving force, the first resonant structure enters a nonlinear amplitude saturation state. Based on the principle of internal resonance, the nonlinear resonant energy of the overload-driven first resonant structure is transferred to the second resonant structure through a coupling beam, driving the second resonant structure to perform torsional or translational resonant motion. The second induction coil cuts the magnetic flux lines, generating a new induced electromotive force signal. The two output electromotive force signals are processed and converted into DC signals respectively, and then the two DC signals are summed to reflect the strength of the magnetic field. The ratio of the natural frequency of the first resonant structure to the natural frequency of the second resonant structure is an integer multiple; The first resonant structure adopts a low-frequency structure, and the second resonant structure adopts a high-frequency structure; or the first resonant structure adopts a high-frequency structure, and the second resonant structure adopts a low-frequency structure.

2. The internal resonant coupled electromagnetic induction micromechanical magnetic sensor according to claim 1, characterized in that: The vibration modes corresponding to the resonant modes of the first resonant structure and the second resonant structure are the same, and are both torsional resonant modes or both in-plane translational modes; If it is a torsional mode, the driving electrode and the sensing electrode should be respectively arranged between the first resonant structure and the substrate sheet, and between the second resonant structure and the substrate sheet; If it is an in-plane translational mode, the driving electrodes and the sensing electrodes are arranged at any position suitable for driving and detecting the translational mode of the structure around the first resonant structure and the second resonant structure.

3. The internal resonant coupled electromagnetic induction micromechanical magnetic sensor according to claim 1, characterized in that: The first resonant structural assembly and the second resonant structural assembly each further include an anchor point and a support beam; The anchor point is provided on the substrate; One end of the support beam is fixedly connected to the anchor point, and the other end of the support beam is fixedly connected to the first resonant structure or the second resonant structure.

4. The internal resonant coupled electromagnetic induction micromechanical magnetic sensor according to claim 1, characterized in that: The first induction coil and the second induction coil form at least one layer; the number of turns of each layer of the first induction coil and the second induction coil is at least one turn; When the first induction coil is multi-layered, an isolation insulating layer is provided between two adjacent layers of the first induction coil; when the second induction coil is multi-layered, an isolation insulating layer is provided between two adjacent layers of the second induction coil; When the first induction coil has multiple turns, the winding direction of each turn of the first induction coil is the same; when the second induction coil has multiple turns, the winding direction of each turn of the second induction coil is the same.

5. The internal resonant coupled electromagnetic induction micro-machined magnetic sensor according to claim 1, wherein: The first resonant structure component and the second resonant structure component each further include at least two pads, The two pads are respectively connected to two ends of the first induction coil or two ends of the second induction coil.

6. The internal resonant coupled electromagnetic induction micro-machined magnetic sensor according to claim 1, characterized in that: The resonant motion modes of the first resonant structure and the second resonant structure are torsional motion or translational motion.

7. A method for preparing an electromagnetic induction micro-machined magnetic sensor with internal resonance coupling according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Prepare a device silicon wafer and form a cavity structure on the surface of the device silicon wafer through photolithography and etching processes; (2) preparing a substrate sheet and forming a substrate insulating layer on the surface of the substrate sheet; (3) depositing a driving electrode metal layer on the surface of the insulating layer at the substrate, and forming the driving electrode and the substrate metal layer by photolithography and etching processes; (4) Perform face-to-face eutectic bonding of the metal dielectric layer on the cavity pattern side of the device silicon wafer and the electrode pattern side of the substrate wafer; (5) Thinning the device silicon wafer by etching; (6) depositing an insulating layer on the surface of the device silicon wafer, and forming a first silicon body insulating layer and a second silicon body insulating layer by photolithography and etching processes; (7) forming a first induction coil and a second induction coil on the surface of the first silicon body insulating layer and the second silicon body insulating layer respectively by deposition and etching processes; (8) depositing an insulating layer on the surface of the first induction coil and the second induction coil, and forming a first coil insulating layer and a second coil insulating layer respectively by photolithography and etching processes; (9) depositing a metal layer on the first coil insulation layer and the second coil insulation layer, and forming a first coil metal layer and a second coil metal layer by etching; (10) Etching the device silicon wafer to form a coupling beam to connect the internal resonance coupling resonant structure of the two resonant structures.

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