A ground sensor sensitive chip based on magnetoelectric coupling material and a preparation method thereof

Abstract

A ground sensor sensitive chip based on magnetoelectric coupling material and a preparation method thereof, relate to the field of ground sensor and micro-electro-mechanical system (MEMS), and solve the problem that the ground sensor cannot meet the demand of ground target detection in terms of power consumption, miniaturization, sensitivity and other indexes. The mass block of the sensitive chip is arranged at the center of the fixed support frame, and the two are connected and fixed through four sensitive beams; the four sensitive beams are arranged in an axisymmetric form between the mass block and the fixed support frame, and the upper surfaces of the sensitive beams, the mass block and the fixed support frame are located on the same horizontal plane. The preparation process is roughly as follows: isolation layer manufacturing is performed on the silicon wafer; the bonding of the isolation layer and the magnetoelectric coupling sensitive area is realized by manufacturing a PI interlayer on the isolation layer; the magnetoelectric coupling sensitive area, the PI interlayer, the isolation layer and the single crystal silicon are patterned by using photoetching, dry etching and wet etching processes; and the mass block is installed by using a D2W process.

Description

Technical Field

[0001] This invention belongs to the field of ground sensor and microelectromechanical system (MEMS) technology, and particularly relates to a sensitive chip of a ground sensor and its fabrication method. Background Technology

[0002] Ground sensors are core sensing devices in fields such as battlefield reconnaissance, security monitoring, border security, and geological exploration. They primarily detect and process weak physical signals by sensing dynamic changes in physical quantities such as magnetic fields, sound waves, ground vibrations, and infrared radiation caused by the movement of ground targets. This allows for the accurate detection, identification, tracking, and positioning of ground targets. Compared to traditional detection equipment such as battlefield reconnaissance radar, optical reconnaissance equipment, and night vision reconnaissance equipment, ground sensors, based on the principle of sensing ground physical quantities, overcome the technical bottlenecks of traditional detection equipment, such as line-of-sight obstruction, terrain limitations, and ground object obstruction. They can effectively cover blind spots that traditional detection equipment cannot reach, and possess outstanding advantages such as all-weather, all-terrain capability, strong concealment, and flexible deployment. They are an indispensable core sensing unit in unmanned ground reconnaissance and distributed security monitoring systems, and have irreplaceable application value in modern intelligent unmanned monitoring, battlefield situational awareness, and border security early warning scenarios.

[0003] With the development trend of miniaturization, low power consumption, long endurance, and high sensitivity in unmanned monitoring systems, the industry has placed higher demands on the comprehensive performance indicators of ground sensors. Low power consumption, miniaturization, and high sensitivity in detecting characteristic signals have become the core R&D directions for the next generation of ground sensors. However, current ground sensor technology still has many technical shortcomings that are difficult to overcome, and its core performance indicators cannot meet the practical application requirements of high precision, long time range, and unattended operation. While the existing mainstream induction coil ground sensors have the advantage of high detection sensitivity under normal conditions and are a commonly used technical solution in the current ground sensing field, their inherent structure and working principle lead to two fatal flaws: First, the induction coil structure design is complex and has low integration, resulting in a large overall device size, making it difficult to achieve miniaturized chip integration design and unable to adapt to the application scenarios of miniaturized, lightweight, and high-density deployment of unattended sensing equipment; second, the power consumption of this type of sensor remains high, generally reaching the mW level or above, which consumes a lot of energy storage resources of unattended systems.

[0004] The shortcomings of existing technologies directly lead to a series of application challenges: high power consumption significantly shortens the battery life of unattended ground-based sensing systems, failing to meet the requirements for long-term unattended monitoring and 24 / 7 combat readiness in the field; the large size of the devices limits the integration and array deployment of sensors, reducing the flexibility and concealment of the monitoring system; simultaneously, traditional sensors have poor adaptability in the detection dimension of characteristic signal frequencies, insufficient ability to capture weak ground target disturbance signals, and their detection sensitivity and signal resolution are difficult to adapt to the precise detection requirements in complex field environments. In summary, traditional ground sensors have significant technical bottlenecks in the three core indicators of power consumption, miniaturization, and characteristic frequency detection sensitivity, severely restricting the iterative upgrade of ground-based sensing and monitoring systems towards miniaturization, low power consumption, high sensitivity, long battery life, and intelligence.

[0005] To address the aforementioned shortcomings of existing technologies, this invention proposes a ground sensor sensitive chip based on magnetoelectric coupling materials and its fabrication method. It innovatively employs magnetoelectric coupling materials to construct the core sensing structure, achieving direct coupling between electromagnetic-vibration and piezoelectric-vibration transduction modes, thus overcoming the technical limitations of traditional induction coil sensors at the physical mechanism level. This invention achieves autonomous gain of the sensing signal through a novel transduction coupling design, significantly reducing sensor power consumption to the μW level. Simultaneously, it addresses the requirements of miniaturized device integration design and high-sensitivity detection of characteristic frequency signals, effectively solving the industry pain points of high power consumption, large size, and insufficient sensitivity in characteristic signal detection in traditional ground sensors. This provides a new and reliable technical solution for the optimized design and mass production of high-performance ground sensor sensitive chips. Summary of the Invention

[0006] This invention aims to address the problem that existing ground sensors cannot meet application requirements in terms of power consumption, miniaturization, and sensitivity, and proposes a ground sensor sensitive chip based on magnetoelectric coupling material and its fabrication method.

[0007] A ground sensor sensing chip based on magnetoelectric coupling material consists of four sensing microbeams, a central mass block, and a fixed support frame; the four sensing microbeams have the same geometric dimensions. The central mass block is coaxially arranged at the geometric center of the fixed frame. The central mass block and the fixed frame are elastically supported and rigidly connected by four sensitive microbeams. All sensitive microbeams are arranged symmetrically between the central mass block and the fixed frame along the central axis, and the upper surfaces of the sensitive microbeams, the central mass block, and the fixed frame are coplanar.

[0008] The method for fabricating a ground sensor sensitive chip based on a magnetoelectric coupling material according to the present invention is carried out according to the following steps: 1. A silicon-based insulating layer is generated by processing the silicon wafer substrate using a thermal oxidation process; II. A Cr / Au / Cr stacked lower electrode was fabricated on the surface of a PMNT piezoelectric substrate using magnetron sputtering to obtain a PMNT functional substrate. 3. A PI polyimide bonding layer is prepared by spin-coating on the surface of a silicon-based isolation layer. The heterogeneous bonding integration of the silicon substrate and the PMNT functional substrate is completed through a one-time wafer bonding, surface thinning and precision polishing process to obtain the bonded PMNT layer. IV. A Cr / Au / Cr stacked top electrode was deposited on the surface of the bonded PMNT layer using a magnetron sputtering process to obtain a composite substrate. 5. A PI adhesive layer is spin-coated onto the surface of the upper electrode of the composite substrate. After curing, it serves as an intermediate transition layer. This PI adhesive layer is used to complete the secondary wafer bonding between the Metglas magnetostrictive substrate and the existing composite substrate, thus constructing a complete PMNT / Metglas magnetoelectric coupling bilayer composite structure. 6. The unprotected Metglas regions are removed using photolithography and dry etching. Then, using the patterned Metglas layer as a hard mask, the PI layer is dry-etched using RIE (Reverse Etching). A photoresist mask is fabricated, and Au and Cr etchants are used to remove the unprotected areas of the Cr / Au / Cr layers in the upper electrode. Next, using the patterned upper electrode layer as a hard mask, the PMNT layer is etched using ICP (Inductively Coupled Printing) dry etching. A photoresist mask is then fabricated on the substrate surface. Au and Cr etchants are used to sequentially remove unprotected areas of each Cr / Au / Cr layer in the lower electrode until the PI layer is etched. RIE (Rapid Etching) is then used to dry-etch the substrate, removing areas of the PI layer not protected by the lithography machine, until the underlying SiO2 layer is etched. ICP (Inductively Coupled Printing) dry etching is then used to etch the back side of the substrate until the underlying SiO2 layer is etched. The remaining SiO2 layer on the back side of the substrate is removed with SiO2 etchant. This completes the patterning etching process for the sensitive chip. VII. Mass Block Integration and Packaging: Using the D2W wafer-to-wafer bonding process, a high-density mass block made of tungsten steel is precisely bonded and fixed to the center position of the sensitive microbeam structure, completing the fabrication of the overall magnetoelectric coupling type MEMS ground sensor sensitive chip.

[0009] The beneficial effects of this invention are: This invention employs a PMNT piezoelectric layer / Metglas magnetostrictive layer magnetoelectric coupling transduction mechanism, completely eliminating the energy-consuming structure of traditional coils from a physical perspective. The core principle is as follows: vibration stress caused by ground target disturbance is transmitted to the sensitive microbeam, simultaneously exciting the magnetostrictive layer to undergo magnetostrictive deformation and the piezoelectric layer to generate a piezoelectric effect, achieving direct coupling through both electromagnetic-vibration and piezoelectric-vibration dual transduction methods. This coupling mechanism enables passive physical signal self-gain, eliminating the need for continuous power supply to maintain the induced magnetic field. It relies solely on the magnetoelectric coupling effect of the materials themselves to efficiently convert weak physical signals into electrical signals, without requiring additional gain compensation from backend circuitry. Based on this physical mechanism, the device's power consumption is significantly reduced from the traditional mW level to the μW level, fundamentally solving the application problems of high power consumption, short battery life, and inability to operate unattended for extended periods inherent in traditional sensors.

[0010] This invention utilizes MEMS micro-nano fabrication technology to construct a thin-film stacked magnetoelectric coupling composite structure. It highly integrates a PMNT piezoelectric functional layer, a Metglas magnetostrictive functional layer, and nanoscale stacked electrodes onto a silicon substrate, eliminating the bulky structure of traditional discrete coils and independent magnetic cores. Simultaneously, it combines a symmetrical microbeam + central mass block integrated chip structure design, with all functional structures integrally etched and formed, eliminating additional discrete components. This significantly reduces the overall device size, achieving chip-level miniaturization and integration of the sensor. This meets the requirements for miniaturized, high-density, and highly concealed field deployments, solving the problems of large size, poor integration, and limited deployment of traditional sensors.

[0011] This invention enhances detection sensitivity through a dual mechanism of material coupling gain and structural anti-interference optimization: First, the magnetoelectric coupling composite structure combines piezoelectric and magnetostrictive effects. The synergistic coupling of these two physical effects enables dual sensing and amplification of weak ground vibrations and magnetic field characteristic signals, significantly improving the ability to identify and convert low-frequency weak characteristic signals, thus adapting to weak target detection scenarios in complex field environments. Second, the four-microbeam central axis symmetrical layout structure ensures that under acceleration excitation, the central mass block only translates along the excitation direction without torsional offset. The tensile and compressive deformations are completely symmetrical, which can completely eliminate invalid lateral sensitivity output, avoid stray signal interference, and greatly improve the detection accuracy and resolution of effective signals, solving the problems of insufficient characteristic frequency detection sensitivity and poor signal anti-interference capability of traditional sensors. Attached Figure Description

[0012] Figure 1 This is a top view of the ground sensor sensitive chip designed in this invention, wherein 1 is the sensitive beam, 2 is the mass block, 3 is the fixed support frame, and 5 is the metal electrode and lead wire. Figure 2This is a cross-sectional schematic diagram of the ground sensor sensitive chip designed in this invention, wherein 1 is the sensitive beam, 2 is the mass block, 3 is the fixed support frame, 4 is the magnetoelectric coupling sensitive area, and 5 is the metal electrode and lead wire. Figure 3 This is a cross-sectional view of the silicon wafer in the embodiment; Figure 4 This is a cross-sectional view of the substrate after the isolation layer was prepared in the embodiment; Figure 5 This is a cross-sectional view of the substrate after the lower electrode was fabricated in the embodiment; Figure 6 This is a cross-sectional view of the sensitive chip after one bonding and thinning polishing process in the embodiment. Figure 7 This is a cross-sectional view of the sensitive chip after the upper electrode is fabricated in the embodiment; Figure 8 This is a cross-sectional view of the sensitive chip after secondary bonding in the embodiment; Figure 9 This is a cross-sectional view of the sensitive chip after patterned etching in the embodiment; Figure 10 This is a cross-sectional view of the ground sensor sensing chip after the mass block is installed in the embodiment. Detailed Implementation

[0013] Specific Implementation Method 1: In this implementation method, a ground sensor sensitive chip based on magnetoelectric coupling material consists of four sensitive microbeams 1, a central mass block 2, and a fixed support frame 3; the four sensitive microbeams have the same geometric dimensions; The central mass block 2 is coaxially arranged at the geometric center of the fixed support frame 3. The central mass block 2 and the fixed support frame 3 are elastically supported and rigidly connected by four sensitive microbeams. All sensitive microbeams 1 are arranged symmetrically between the central mass block 2 and the fixed support frame 3 along the central axis, and the upper surfaces of the sensitive microbeams 1, the central mass block 2, and the fixed support frame 3 are coplanar.

[0014] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that: the four sensitive microbeams 1 are arranged one-to-one at the midpoints of each side of the upper surface of the central mass block 2, and the corresponding connecting edges of a single sensitive microbeam 1 and the central mass block 2 are arranged perpendicularly and orthogonally. Everything else is the same as in Specific Implementation Method One.

[0015] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One in that each of the aforementioned sensitive microbeams 1 has a magnetoelectric coupling sensitive unit 4 integrated on its surface, and the ground sensor sensitive chip based on the magnetoelectric coupling material integrates a total of four magnetoelectric coupling sensitive units 4. Everything else is the same as in Specific Implementation Method One.

[0016] Specific Implementation Method Four: This implementation method differs from Specific Implementation Method Three in that the four magnetoelectric coupling sensing units 4 adopt a homogeneous and identical design; each magnetoelectric coupling sensing unit 4 is located at both ends of the upper surface of the corresponding sensing microbeam 1, and adjacent magnetoelectric coupling sensing units 4 are interconnected through metal electrodes and leads 5. Everything else is the same as in Specific Implementation Method Three.

[0017] Specific Implementation Method Five: This implementation method differs from Specific Implementation Method Four in that the magnetoelectric coupling sensitive unit 4 adopts a double-layer heterogeneous composite functional structure. The stacked structure from the substrate to the surface consists of a PMNT piezoelectric layer and a Metglas magnetostrictive layer, forming a regular magnetoelectric coupling composite heterogeneous structure. The thicknesses of the two functional layers are 50 μm and 20 μm, respectively. Everything else is the same as in Specific Implementation Method Four.

[0018] Specific Implementation Method Six: The preparation method of the ground sensor sensitive chip based on magnetoelectric coupling material in this implementation method is carried out according to the following steps: 1. A silicon-based insulating layer is generated by processing the silicon wafer substrate using a thermal oxidation process; II. A Cr / Au / Cr stacked lower electrode was fabricated on the surface of a PMNT piezoelectric substrate using magnetron sputtering to obtain a PMNT functional substrate. 3. A PI polyimide bonding layer is prepared by spin-coating on the surface of a silicon-based isolation layer. The heterogeneous bonding integration of the silicon substrate and the PMNT functional substrate is completed through a one-time wafer bonding, surface thinning and precision polishing process to obtain the bonded PMNT layer. IV. A Cr / Au / Cr stacked top electrode was deposited on the surface of the bonded PMNT layer using a magnetron sputtering process to obtain a composite substrate. 5. A PI adhesive layer is spin-coated onto the surface of the upper electrode of the composite substrate. After curing, it serves as an intermediate transition layer. This PI adhesive layer is used to complete the secondary wafer bonding between the Metglas magnetostrictive substrate and the existing composite substrate, thus constructing a complete PMNT / Metglas magnetoelectric coupling bilayer composite structure. 6. The unprotected Metglas regions are removed using photolithography and dry etching. Then, using the patterned Metglas layer as a hard mask, the PI layer is dry-etched using RIE (Reverse Etching). A photoresist mask is fabricated, and Au and Cr etchants are used to remove the unprotected areas of the Cr / Au / Cr layers in the upper electrode. Next, using the patterned upper electrode layer as a hard mask, the PMNT layer is etched using ICP (Inductively Coupled Printing) dry etching. A photoresist mask is then fabricated on the substrate surface. Au and Cr etchants are used to sequentially remove unprotected areas of each Cr / Au / Cr layer in the lower electrode until the PI layer is etched. RIE (Rapid Etching) is then used to dry-etch the substrate, removing areas of the PI layer not protected by the lithography machine, until the underlying SiO2 layer is etched. ICP (Inductively Coupled Printing) dry etching is then used to etch the back side of the substrate until the underlying SiO2 layer is etched. The remaining SiO2 layer on the back side of the substrate is removed with SiO2 etchant. This completes the patterning etching process for the sensitive chip. VII. Mass Block Integration and Packaging: Using the D2W wafer-to-wafer bonding process, a high-density mass block made of tungsten steel is precisely bonded and fixed to the center position of the sensitive microbeam structure, completing the fabrication of the overall magnetoelectric coupling type MEMS ground sensor sensitive chip.

[0019] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method Six in that the silicon substrate used in step one is an N-type 100 monocrystalline silicon wafer with a resistivity of 2–6 Ω·cm. Everything else is the same as in Specific Implementation Method Six.

[0020] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method Six in that the thickness of the silicon-based isolation layer in step one is controlled at 300~360nm. Everything else is the same as in Specific Implementation Method Six.

[0021] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Method Six in that the SiO2 etching solution mentioned in step six is ​​a mixed solution of HF, NH4F, and deionized water. Everything else is the same as in Specific Implementation Method Six.

[0022] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Method Six in that both the Cr / Au / Cr stacked upper electrode and the Cr / Au / Cr stacked lower electrode adopt a Cr / Au / Cr multilayer composite conductive structure, with the thickness parameters of each electrode layer being 10nm, 100nm, and 10nm respectively. Everything else is the same as in Specific Implementation Method Six.

[0023] The beneficial effects of the present invention are verified through the following embodiments: This embodiment provides a ground sensor sensitive chip and its fabrication method, namely: a mass block is suspended from a fixed frame by four sensitive beams connected to its upper surface, such as... Figure 1As shown.

[0024] Under lateral acceleration excitation, the mass block is in torque equilibrium and translates along the acceleration direction, without torsion due to the fixing effect of the four sensitive beams. The sensitive beam at one end of the mass block is stretched, while the other end is compressed. Due to the structural symmetry, the tensile and compressive deformations are equal in magnitude, resulting in equal changes in the magnetoelectric coupling sensitive area. This design completely eliminates the lateral sensitivity output of the ground sensor.

[0025] This embodiment describes a method for fabricating a ground sensor sensing chip based on magnetoelectric coupling materials. The method includes: Using an N-type 100 monocrystalline silicon wafer with a resistivity of 2–6 Ω·cm, determine the crystal orientation tangent of the (100) double-polished monocrystalline silicon wafer. For example... Figure 3 As shown; A SiO2 isolation layer with a thickness of 300-360 nm was prepared on a single-crystal silicon wafer using a thermal oxidation film deposition process; Figure 4 As shown; Electrodes were sputtered onto the surface of a PMNT substrate using magnetron sputtering. The electrodes had a stacked structure, consisting of Cr / Au / Cr layers with thicknesses of 10 / 100 / 10 nm. Figure 5 As shown; A 10 μm thick polyimide (PI) layer was prepared on a silicon wafer with an isolation layer using a spin coating process and a spin coater.

[0026] Next, using polyimide as an interlayer, this substrate was bonded to a PMNT substrate with a lower electrode. The bonding surfaces of the two substrates were the side with polyimide and the side with the lower electrode, respectively. After this bonding, mechanical thinning and polishing processes were used to thin the PMNT layer on the substrate to 50 μm. Figure 6 As shown; A top electrode was sputtered onto the PMNT surface of a thinned and polished substrate using magnetron sputtering. The top electrode had a stacked structure, with each layer consisting of Cr / Au / Cr layers, corresponding to thicknesses of 10 / 100 / 10 nm. Figure 7 As shown; PI adhesive was uniformly coated onto the substrate using spin coating and a spin coater, with the thickness controlled to be between 5 μm and 7 μm. The PI adhesive layer was then pre-cured, serving as an intermediary layer for secondary bonding between the Metalas substrate and the substrate. Figure 8 As shown; Curing temperature: 250℃-400℃, time: 5min-10min, pressure: 2000N; The unprotected Metglas portion was removed using photolithography and dry etching processes. RIE: Etching power: 680 W, gas ratio: Ar, etching rate: 80-1000 Å / min, etching time: 3h-6h; Next, using the patterned Metglas layer as a hard mask, the PI layer is dry etched using the RIE dry etching process. RIE: Etching gas: O2, etching rate: 1-2 μm / min, etching time: 5-10 min.

[0027] A photoresist mask is fabricated, and Au and Cr etching solutions are used to remove the unprotected areas of each Cr / Au / Cr layer in the upper electrode. Au etching solution: Composition: a mixed solution of I2 and KI (I2: 5 g / L, KI: 20 g / L), etching temperature: 20℃-30℃, etching rate: 0.8 μm / min.

[0028] Cr corrosion solution: ratio: cerium ammonium nitrate: nitric acid: deionized water = 14:1:85 (weight ratio), corrosion temperature: 20℃-30℃, corrosion rate: 1μm / min.

[0029] Next, using the patterned upper electrode layer as a hard mask, the PMNT layer was etched using an ICP dry etching process. ICP: Etching power: 1000 W, gas ratio: Ar, etching rate: 80-1500 Å / min, etching time: 3h-6h.

[0030] A photoresist mask is fabricated on the substrate surface. Au etchant and Cr etchant are used to remove the unprotected areas of each Cr / Au / Cr layer in the lower electrode in turn until the PI layer is etched. Au etching solution: Composition: a mixed solution of I2 and KI (I2: 5 g / L, KI: 20 g / L), etching temperature: 20℃-30℃, etching rate: 0.8 μm / min.

[0031] Cr corrosion solution: ratio: cerium ammonium nitrate: nitric acid: deionized water = 14:1:85 (weight ratio), corrosion temperature: 20℃-30℃, corrosion rate: 1μm / min.

[0032] Next, the substrate is dry-etched using RIE (Reverse Etching) to remove areas of the PI layer not protected by the photolithography machine, until the underlying SiO2 is etched down. The back side of the substrate is then etched using ICP (Inductively Coupled Printing) dry etching until the underlying SiO2 layer is reached. Any remaining SiO2 layer on the back side of the substrate is removed using a SiO2 etchant (a mixed solution of HF, NH4F, and deionized water). This completes the patterning etching process for the sensitive chip. Figure 9 As shown; RIE: Etching gas: O2, etching rate: 1-2 μm / min, etching time: 5-10 min.

[0033] ICP: Etching power: 2000W, gas ratio: SF6+CF4, etching rate: 8-10μm / min, etching time: 40min~50min. The mass block was bonded to the center of the cantilever beam of the sensing unit using the D2W process to complete the fabrication of the sensing chip. The mass block was made of tungsten carbide. Microbeam length: 1000±10μm, width: 50±5μm, thickness: 10±1μm; Mass block dimensions: 200μm×200μm×200μm, material: tungsten carbide; D2W: Alignment accuracy: <500 nm; Operating temperature: 20℃~40℃.

[0034] The ground sensor fabricated using this sensitive chip was tested and found to have a vibration sensitivity of ≥5V / g.

Claims

1. A ground sensor sensing chip based on magnetoelectric coupling material, characterized in that... The ground sensor sensitive chip based on magnetoelectric coupling material consists of four sensitive microbeams (1), a central mass block (2), and a fixed support frame (3); the four sensitive microbeams have the same geometric dimensions; The central mass block (2) is coaxially arranged at the geometric center of the fixed support frame (3). The central mass block (2) and the fixed support frame (3) are elastically supported and rigidly connected by four sensitive microbeams. All sensitive microbeams (1) are arranged symmetrically between the central mass block (2) and the fixed support frame (3) along the central axis, and the upper surfaces of the sensitive microbeams (1), the central mass block (2), and the fixed support frame (3) are coplanar.

2. The ground sensor sensing chip based on magnetoelectric coupling material according to claim 1, characterized in that... The four sensitive microbeams (1) are arranged one-to-one at the midpoint of each side of the upper surface of the central mass block (2), and the corresponding connecting side of each sensitive microbeam (1) and the central mass block (2) are arranged perpendicularly and orthogonally.

3. A ground sensor sensing chip based on magnetoelectric coupling material according to claim 1, characterized in that... Each of the aforementioned sensitive microbeams (1) has a magnetoelectric coupling sensitive unit (4) integrated on its surface. The ground sensor sensitive chip based on the magnetoelectric coupling material integrates a total of four magnetoelectric coupling sensitive units (4).

4. A ground sensor sensing chip based on magnetoelectric coupling material according to claim 3, characterized in that... The four magnetoelectric coupling sensitive units (4) adopt a homogeneous and homogeneous design; each magnetoelectric coupling sensitive unit (4) is set at both ends of the upper surface of the corresponding sensitive microbeam (1), and adjacent magnetoelectric coupling sensitive units (4) are interconnected by metal electrodes and leads (5).

5. A ground sensor sensing chip based on magnetoelectric coupling material according to claim 4, characterized in that... The magnetoelectric coupling sensitive unit (4) adopts a double-layer heterogeneous composite functional structure. The stacked structure from the substrate to the surface layer consists of a PMNT piezoelectric layer and a Metglas magnetostrictive layer, forming a regular magnetoelectric coupling composite heterogeneous structure. The thicknesses of the two functional layers are 50 μm and 20 μm, respectively.

6. The method for fabricating a ground sensor sensitive chip based on a magnetoelectric coupling material as described in claim 1, characterized in that... The fabrication method of the ground sensor sensitive chip based on magnetoelectric coupling material is carried out according to the following steps:

1. A silicon-based insulating layer is generated by processing the silicon wafer substrate using a thermal oxidation process; II. A Cr / Au / Cr stacked lower electrode was fabricated on the surface of a PMNT piezoelectric substrate using magnetron sputtering to obtain a PMNT functional substrate.

3. A PI polyimide bonding layer is prepared by spin-coating on the surface of a silicon-based isolation layer. The heterogeneous bonding integration of the silicon substrate and the PMNT functional substrate is completed through a one-time wafer bonding, surface thinning and precision polishing process to obtain the bonded PMNT layer. IV. A Cr / Au / Cr stacked top electrode was deposited on the surface of the bonded PMNT layer using a magnetron sputtering process to obtain a composite substrate.

5. A PI adhesive layer is spin-coated onto the surface of the upper electrode of the composite substrate. After curing, it serves as an intermediate transition layer. This PI adhesive layer is used to complete the secondary wafer bonding between the Metglas magnetostrictive substrate and the existing composite substrate, thus constructing a complete PMNT / Metglas magnetoelectric coupling bilayer composite structure.

6. The unprotected Metglas portion is removed using photolithography and dry etching processes; then, using the patterned Metglas layer as a hard mask, the PI layer is dry etched using RIE dry etching process. A photoresist mask is fabricated, and Au and Cr etchants are used to remove the unprotected areas of each Cr / Au / Cr layer in the upper electrode. Then, using the patterned upper electrode layer as a hard mask, the PMNT layer is etched using an ICP dry etching process. A photoresist mask is fabricated on the substrate surface. Au etchant and Cr etchant are used to remove the unprotected areas of each Cr / Au / Cr layer in the lower electrode in turn until the PI layer is etched. Continue using the RIE process to dry etch the substrate to remove the areas of the PI layer that are not protected by the photolithography machine, until the SiO2 layer below is etched down; The back side of the substrate is etched using the ICP dry etching process until the underlying SiO2 layer is reached; the remaining SiO2 layer on the back side of the substrate is removed using SiO2 etchant; and the patterning etching process of the sensitive chip is completed. VII. Mass Block Integration and Packaging: Using the D2W wafer-to-wafer bonding process, a high-density mass block made of tungsten steel is precisely bonded and fixed to the center position of the sensitive microbeam structure, completing the fabrication of the overall magnetoelectric coupling type MEMS ground sensor sensitive chip.

7. The method for fabricating a ground sensor sensitive chip based on a magnetoelectric coupling material according to claim 6, characterized in that... The silicon substrate mentioned in step one is an N-type 100 monocrystalline silicon wafer with a resistivity of 2 to 6 Ω·cm.

8. The method for fabricating a ground sensor sensitive chip based on a magnetoelectric coupling material according to claim 6, characterized in that... In step one, the thickness of the silicon-based isolation layer is controlled at 300~360nm.

9. The method for fabricating a ground sensor sensitive chip based on a magnetoelectric coupling material according to claim 6, characterized in that... The SiO2 etching solution mentioned in step six is ​​a mixed solution of HF, NH4F and deionized water.

10. A method for fabricating a ground sensor sensitive chip based on a magnetoelectric coupling material according to claim 6, characterized in that... Both the Cr / Au / Cr stacked upper electrode and the Cr / Au / Cr stacked lower electrode adopt a Cr / Au / Cr multilayer stacked composite conductive structure, and the thickness parameters of each layer of the electrode are 10nm, 100nm, and 10nm respectively.

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