Spin valve magnetic sensor array based on wheatstone bridge and method of manufacturing the same

Abstract

The application provides a spin valve magnetic sensing array based on a Wheatstone bridge and a preparation method thereof. Based on the problem of poor linearity of a conventional spin valve magnetic sensor under a low magnetic field, the application introduces a Wheatstone bridge structure, utilizes a differential measurement and a signal amplification mechanism, and achieves the technical effect of effectively improving the linear response of the sensor in a low magnetic field range.

Description

Technical Field

[0001] This invention relates to the technical field of flexible magnetoelectronic devices, and more specifically, to a spin valve magnetic sensing array based on a Wheatstone bridge and its fabrication method. Background Technology

[0002] Magnetoelectronic devices have been widely used in hard disk drive heads, magnetic random access memory, and high-precision sensors due to their unique physical effects (such as giant magnetoresistance (GMR) and tunnel magnetoresistance (TMR)). However, traditional magnetoelectronic devices are usually fabricated on rigid substrates such as silicon and glass, and their inherent brittleness and rigidity severely limit their application in emerging flexible and even stretchable electronics fields.

[0003] In recent years, with the rapid development of wearable devices, electronic skin, biomedical implantable devices, and soft robots, there has been an urgent demand for flexible, stretchable, lightweight, portable, and conformally fitting electronic devices. As a core component of flexible electronic systems, developing high-performance stretchable magnetic sensors has become a key technology for realizing functions such as motion tracking, biosignal detection (e.g., magnetocardiography, magnetoencephalography), human-computer interaction, and non-contact sensing. Currently, methods for fabricating anisotropic stretchable magnetic sensors have been obtained; however, the following technical drawbacks still exist: 1) signal drift caused by resistance baseline shift due to stress creep; 2) common-mode interference caused by the synchronous effect of temperature / humidity on all sensitive elements.

[0004] The Wheatstone bridge structure can effectively cancel common-mode signals and reduce drift errors, thereby significantly improving the stability and anti-interference capability of magnetic sensing signals. However, the structural integrity and conductivity consistency of existing Wheatstone bridges under large deformation or multi-directional tensile conditions cannot meet the practical requirements of stretchable magnetic sensors.

[0005] Therefore, there is an urgent need for a spin valve magnetic sensing array based on a Wheatstone bridge and its fabrication method. Summary of the Invention

[0006] In view of the above problems, the purpose of this invention is to provide a spin valve magnetic sensing array based on a Wheatstone bridge and a method for its fabrication, so as to solve at least one problem existing in the prior art.

[0007] In a first aspect, the present invention provides a spin valve magnetic sensing array based on a Wheatstone bridge, comprising: a flexible substrate; a plurality of rigid islands arranged in an array on the surface of the flexible substrate; a plurality of magnetic sensing units, each of the magnetic sensing units comprising a patterned giant magnetoresistive thin film disposed on a corresponding rigid island; and a liquid metal circuit disposed on the surface of the flexible substrate for connecting the various magnetic sensing units; the liquid metal circuit comprising a top electrode and a bottom electrode, and an isolation layer disposed at the intersection of the top electrode and the bottom electrode. That is, each rigid island has a giant magnetoresistive thin film patterned as a Wheatstone bridge.

[0008] Furthermore, a preferred technical solution is that the projected area of ​​the giant magnetoresistive film on the rigid island is smaller than the area of ​​the rigid island. It should be noted that the pattern of the giant magnetoresistive film is prepared using a lift-off process, which uses photoresist capable of forming inverted trapezoidal sidewalls of 70-85°. This process facilitates the deposition of the giant magnetoresistive film and the subsequent ultrasonic removal of the photoresist to form the final giant magnetoresistive film.

[0009] Furthermore, a preferred technical solution includes a flexible printed circuit board connected to the liquid metal circuit via anisotropic conductive tape.

[0010] Furthermore, a preferred technical solution is that the material of the liquid metal circuit is liquid metal or silver nanowires.

[0011] Secondly, the present invention provides a method for fabricating a spin valve magnetic sensing array based on a Wheatstone bridge, comprising: forming a sacrificial layer on a rigid temporary substrate and fabricating a flexible substrate on the sacrificial layer; forming an array of rigid islands on the flexible substrate by photolithography; forming a photoresist layer with a Wheatstone bridge pattern having inverted trapezoidal sidewalls on the rigid islands by photolithography; depositing a spin valve multilayer film material on a sample having the photoresist layer, and after resist removal and peeling, obtaining a giant magnetoresistive film corresponding to each rigid island; fabricating a liquid metal circuit; sequentially printing a bottom electrode through a mask, coating and curing a flexible polymer isolation material at the intersection of the bottom electrode and the top electrode to form an isolation layer, and printing a top electrode again through a mask; dissolving the sacrificial layer; and encapsulating the array to complete the fabrication of the magnetic sensing array.

[0012] Further, a preferred technical solution is that the method for depositing a spin valve multilayer film material on a sample having the photoresist layer and obtaining a giant magnetoresistive film corresponding to each rigid island after photoresist stripping includes: generating a spin valve multilayer film on the surface of a sample with a mechanical mask attached by magnetron sputtering; and placing the sample with the generated spin valve multilayer film into acetone for ultrasonic treatment to achieve patterning of the spin valve multilayer film.

[0013] Further, a preferred technical solution is that the step of depositing a spin valve multilayer film material on a sample having the photoresist layer includes: depositing the spin valve multilayer film material on the surface of the sample having the photoresist layer using magnetron sputtering technology, wherein a rigid mechanical mask is used to selectively deposit the spin valve multilayer film in the region where the rigid islands are located. Specifically, the photoresist layer is prepared using AZ5124 photoresist.

[0014] Furthermore, a preferred technical solution is that the sacrificial layer is generated using dextran, and the sacrificial layer is dissolved by soaking in deionized water.

[0015] Thirdly, the present invention provides an application of a spin valve magnetic sensing array based on a Wheatstone bridge, wherein the spin valve magnetic sensing array based on a Wheatstone bridge as described in any one of claims 1 to 4 is applied to an electronic device, and the spin valve magnetic sensing array has a linear response of the output voltage signal to the magnetic field.

[0016] Furthermore, a preferred technical solution is that when the flexible substrate is subjected to an omnidirectional tensile strain of up to 27%, the strain on the rigid island is less than 0.5%.

[0017] This invention discloses a spin valve magnetic sensing array based on a Wheatstone bridge and its fabrication method. By arranging rigid islands in an array and using a Wheatstone bridge pattern, the sensing performance is significantly improved while ensuring the stretchability of the device. The achieved technical effects are as follows: when a flexible substrate is subjected to an omnidirectional tensile strain of up to 27%, the strain in the rigid island region is effectively isolated to below 0.5%, ensuring the mechanical reliability of the magnetic sensor; the introduced Wheatstone bridge structure effectively suppresses common-mode interference and temperature drift, enabling the magnetic sensing array to exhibit excellent linear voltage response. Furthermore, this solution does not rely on complex post-stage compensation circuits. Through the device's own structural design and circuit integration, it maintains high signal stability and linearity under tensile conditions, exhibiting high process integration and reliable performance. This invention is applicable to fields such as tactile perception in humanoid robots, electronic skin, and biomedical sensing, providing an effective technical solution for developing flexible magnetoelectronic devices with both large deformation capabilities and high sensing performance.

[0018] To achieve the foregoing and related objectives, one or more aspects of the invention include the features that will be described in detail below. The following description and accompanying drawings illustrate certain exemplary aspects of the invention. However, these aspects indicate only a few of the various ways in which the principles of the invention can be used. Furthermore, the invention is intended to encompass all such aspects and their equivalents. Attached Figure Description

[0019] Other objects and results of the invention will become more apparent and readily understood with reference to the following description taken in conjunction with the accompanying drawings. In the drawings: Figure 1 A flowchart illustrating the fabrication of rigid islands on a flexible substrate, as provided in an embodiment of the present invention; Figure 2 A flowchart illustrating the fabrication of a patterned giant magnetoresistive thin film on a rigid island, as provided in an embodiment of the present invention; Figure 3 A physical diagram of the magnetic sensing array provided in an embodiment of the present invention; Figure 4 Voltage response curve of a spin valve unit tested by the four-point method according to an embodiment of the present invention; In all the accompanying drawings, the same reference numerals indicate similar or corresponding features or functions. Detailed Implementation

[0020] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. It should be noted that the following embodiments are only used to illustrate the implementation methods and typical parameters of the present invention, and are not intended to limit the parameter range described in the present invention. Reasonable variations derived therefrom are still within the protection scope of the claims of the present invention.

[0021] It should be noted that the endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0022] Unless otherwise defined, all terms, symbols, and other scientific terms used herein are intended to have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In some instances, terms having a conventional meaning are defined herein for clarification or ease of reference, and such definitions should not be construed as indicating a significant difference from conventional understanding in the art. The technical methods described or referenced herein are generally well understood by those skilled in the art and employed by conventional methods. Unless otherwise stated, the use of commercially available kits, reagents, and instruments shall be performed according to the manufacturer's instructions and parameters.

[0023] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0024] Glossary: ​​PI, polyimide; PDMS, polydimethylsilane; GMR, giant magnetoresistive; FPC, flexible printed circuit board.

[0025] Example 1

[0026] S1. Provide a 4-inch silicon wafer with a 300nm silicon dioxide layer on its surface as a rigid temporary substrate, which is then cleaned with oxygen plasma and ready for use.

[0027] A dextran solution was spin-coated onto the surface of a rigid temporary substrate to form a sacrificial layer. The specific method was as follows: Dextran powder was first dissolved in deionized water at a mass fraction of 10%. After thorough stirring at room temperature, the solution was heated on a 60°C heating stage for 3 hours until completely dissolved. Then, a 150W O2 plasma was used to coat a 15mm thick substrate. The surface of a 15mm rigid temporary substrate was treated for 3 minutes to modify the surface of the rigid temporary substrate. Then, the prepared dextran solution was spin-coated on the modified rigid temporary substrate surface at 3000rpm / min for 60s using a spin coater. Finally, it was heated on a heating stage at 180℃ for 60 minutes to completely remove surface moisture.

[0028] S2. Polydimethylsilane (PDMS) is spin-coated onto the surface of a rigid temporary substrate with a dextran film using a spin-coating method. It should be noted that the flexible substrate can be circular or polygonal, and the material used is an elastic substrate with low Young's modulus, such as PDMS or polyurethane.

[0029] The specific method includes: first, mixing the PDMS precursor and curing agent at a mass ratio of 10:1, stirring thoroughly, placing the mixture in a sealed container, and using a mechanical pump to perform vacuum treatment until no air bubbles remain. Then, spin-coating the prepared PDMS onto the dextran film sacrificial layer using a spin coater at a speed of 1000 r / min for 30 seconds and then at 3000 r / min for 1 second, and curing it in a 60 ℃ forced-air oven for 24 hours to form a flexible substrate with a thickness of approximately 100 μm.

[0030] S3. Form an array of rigid islands on a flexible substrate. Specific steps are as follows: Figure 1 As shown, the PDMS surface was treated with 300W O2 plasma for 15 seconds, followed by rotation with positive photoresist (JSR ELPAC WPR-5100) at 1500 r / min for 30 seconds, and then preheated on a 90℃ heating stage for 12 minutes to cure the photoresist. Because the thermal expansion coefficients of PDMS and PI differ significantly, large temperature changes can cause cracks in the semi-cured PI, affecting subsequent photolithography steps. Therefore, a stepped cooling method was used to reduce crack formation. A mask with a specific pattern was then mounted on a UV lithography machine, and UV lithography was performed using a soft-contact exposure mode with an exposure time of 57 seconds and a spacing of 160 μm. The lithographically patterned sample was immersed in developer (RZX-3038) for approximately 2 minutes, and then removed by blowing away the developer and residual photoresist with nitrogen gas at 1.5 atmospheres, resulting in a patterned PI rigid island array.

[0031] It should be noted that the pattern in the mask with the specific pattern can be circular or polygonal. In this embodiment, the pattern is circular. Rigid islands with the pattern are fabricated using photolithography, making their size much smaller than the flexible substrate. For example, circular rigid islands with a diameter of 5-40 μm can be obtained. The number of rigid islands can be 2×2, 3×3, 4×4, or 5×5. In this embodiment, it is 2×2.

[0032] S4. Fabricate patterned giant magnetoresistive thin films on rigid islands. Specific steps are as follows: Figure 2 As shown, the sample surface was treated with 300W O2 plasma for 20s. The positive / negative reversible photoresist (AZ5214) was spin-coated onto the modulus gradient film (PDMS / PI) at 3000rpm / min for 30s. After spin-coating, the sample was pre-baked on a 90℃ heating stage for 150s. The mask was then placed in a UV lithography machine for soft-contact exposure with parameters of 10s exposure time and 160μm spacing. The sample was then heated again on a 117℃ heating stage for 150s and then subjected to FLOOD-E mode overexposure for 35s using a UV lithography machine. The sample was then immersed in developer (ZX-238) for about 40s. After fixing with deionized water, the sample surface was dried with a nitrogen gun to obtain the Wheatstone bridge pattern on the PI rigid island.

[0033] S5. A mechanical mask is attached to the sample surface, and then a multilayer film is grown using magnetron sputtering. The resulting multilayer film is Pt (2nm) / IrMn (10nm) / FeCo (5nm) / Cu (3nm) / FeCo (1nm) / FeNi (6nm) / FeCo (1nm) / Cu (3nm) / FeCo (5nm) / IrMn (10nm) / Ta (4nm), which are respectively a Pt buffer layer (2nm), an IrMn antiferromagnetic layer (10nm), a FeCo ferromagnetic layer (5nm), a Cu nonmagnetic layer (3nm), and a FeNi ferromagnetic layer (6nm). After removing the sample, it is immersed in an acetone solution for ultrasonic treatment at 30°C for 30 seconds. The residual liquid on the sample surface is dried with a nitrogen gun to obtain a patterned GMR film. In other words, a GMR multilayer film is grown on the sample surface with a mechanical mask attached using magnetron sputtering, where only the rigid islands of the mechanical mask are exposed. In this embodiment, the patterned GMR film has inverted trapezoidal sidewalls at 70-85°. The inverted trapezoidal structure ensures that the sputtered metal is discontinuously covered on the photoresist sidewalls (creating breakpoints), ensuring that the metal is deposited very thinly or discontinuously at the top edge of the photoresist, while also forming a noticeable break at the bottom corner. The metal on the substrate and the metal on the photoresist are physically separated. This fundamentally solves the problems of metal residue and pattern roughness after acetone stripping.

[0034] It should be noted that the GMR membrane pattern is not limited to the Wheatstone bridge pattern of this invention, but can also be other types of Wheatstone bridge patterns. For example, in addition to the full-bridge Wheatstone bridge pattern of this invention, a half-bridge Wheatstone bridge pattern can also be used. Specifically, in this invention, a full-bridge Wheatstone bridge pattern is used to achieve linear output. The angle of the Wheatstone bridge arms is a specific 45°.

[0035] S6. Place the mechanical mask onto the sample surface and grow a PT electrode (10nm) using magnetron sputtering. For example... Figure 3 As shown, a platinum metal contact layer is formed at the electrode outlet of the giant magnetoresistive thin film by magnetron sputtering for electrical connection with the subsequent liquid metal circuit. In this embodiment, a PT electrode is used, but in specific implementations, other materials such as copper, gold, or silver can also be used.

[0036] S7. The sample surface was treated with 150W O2 plasma for 3 minutes to increase the surface tension between the PDMS surface and the liquid metal. A 100μm linewidth liquid metal conductor was then applied as the bottom electrode using a mechanical mask. Next, a 0.06mm inner diameter screw-type dispensing needle was used to accurately coat the degassed PDMS mixture at the conductive intersection of the top and bottom electrodes. Heating at 60℃ formed an insulating layer to prevent short circuits. Subsequently, a 100μm linewidth liquid metal conductor was applied as the top electrode using a mechanical mask. The sample after applying the liquid metal circuitry is shown below. Figure 3 As shown. In this embodiment, the liquid metal is gallium, and the elastic electrodes are led out from each rigid island. The material is a stretchable conductor, such as liquid metal or silver nanowires. The liquid metal can be a gallium-based alloy, such as gallium-indium alloy.

[0037] S8. Apply anisotropic conductive tape (3M9703) to the FPC connection, then heat at 150°C for 5 hours to connect the FPC cable board to the spin valve array to achieve selective path of the conductive tape.

[0038] S9. A small incision is made on the surface of the cured PDMS film, and it is immersed in a petri dish filled with deionized water for about 1 hour to allow the dextran at the bottom of the flexible substrate to fully dissolve in the water. This releases the flexible substrate, rigid island, giant magnetoresistive film, and liquid metal circuit structure from the rigid temporary substrate. In other words, multiple magnetic sensing units are obtained, each comprising a patterned giant magnetoresistive film fabricated on a corresponding rigid island, with the giant magnetoresistive film having an area smaller than that of the rigid island.

[0039] S10. Finally, PU is used for bottom and surface encapsulation to form a stable sandwich structure. That is, the top and bottom electrodes are printed with liquid metal, and PDMS is used as an isolation layer to isolate the cross circuits of the top and bottom electrodes. Anisotropic conductive tape (3M9703) is used to achieve electrical and mechanical connection between the flexible printed circuit board (FPC) and the spin valve array. Finally, PU tape is used for encapsulation.

[0040] Through the above process, an omnidirectionally stretchable spin valve magnetic sensing array based on an energized bridge can be obtained.

[0041] The voltage response curves were measured using the four-point method when the applied magnetic field was perpendicular to and parallel to the pinning direction. Figure 4 As shown, curve H is obtained. Y Hx. Among them, the testing equipment is an electromagnet from Beijing Chaorui Renda Technology Co., Ltd.

[0042] Through observation Figure 4It can be seen that when an external magnetic field Hy is applied along the Y direction to a spin valve unit with a full-bridge Wheatstone bridge, the spin valve exhibits a linear response within the magnetic field range of -50 Oe to 50 Oe. In contrast, when an external magnetic field Hx is applied along the X direction to the spin valve unit, the output signal of the device remains essentially unchanged within this linear range.

[0043] Comparative Example 1

[0044] S1. Provide a 4-inch silicon wafer with a 300nm silicon dioxide layer on its surface as a rigid temporary substrate, which is then cleaned with oxygen plasma and ready for use.

[0045] S2. Mix the precursor of the high elastic substrate and the curing agent evenly according to the preset weight ratio and spin coat them onto the upper layer. After drying and curing, a high elastic substrate thin film layer is obtained.

[0046] S3. Spin-coat photoresist onto the upper layer, dry and cure it, and then use a photolithography plate with a specific pattern to perform photolithography to obtain an array of rigid islands. Then, perform development, fixing, drying and curing in sequence to obtain several rigid islands.

[0047] S4. Several magnetic thin films with spin valve structures are grown on the previous layer by magnetron sputtering to obtain the magnetic sensor layer.

[0048] S5. Each rigid island in the array of rigid islands has several elastic electrodes led out from the corresponding magnetic sensor, and the led-out elastic electrodes are attached to the highly elastic substrate thin film layer.

[0049] The above process yields an omnidirectionally stretchable magnetic sensing array. Using the four-point method of Example 1, the voltage response curves when the applied magnetic field is perpendicular to and parallel to the pinning direction were tested. The response of the spin valve unit in Comparative Example 1 to the magnetic field signal is nonlinear. Therefore, existing magnetic sensing arrays are only suitable for use with switch-type sensors and are difficult to quantitatively detect.

[0050] Example 2

[0051] Integrating a spin valve magnetic sensing array, prepared according to the method of this invention and possessing omnidirectional stretchability and excellent linear output, onto the skin surface of a humanoid robot's fingertips or joints can constitute a high-precision tactile sensing unit. By embedding a micromagnet array at the contact interface and sensing the local magnetic field changes caused by contact with an object, the sensing array can output an electrical signal in real time that is linearly related to the magnitude and distribution of the contact force. Thanks to the strain isolation characteristics and signal stability of the device under tension, it can deform with the bending and stretching of the robot's joints without affecting its sensing performance. This tactile sensing unit features high spatial resolution, high linearity, and resistance to temperature interference, providing a reliable sensing solution for humanoid robots to achieve precise operation, adaptive grasping, and safe interaction.

[0052] Example 3

[0053] By integrating the spin valve magnetic sensing array prepared according to the method of this invention with a flexible power supply and signal processing circuit, a magnetic induction functional layer for electronic skin can be constructed. This functional layer can be adhered to the surface of human skin or a biomimetic carrier, and by detecting changes in the distribution of the surrounding magnetic field, it can achieve functions such as gesture recognition, limb movement trajectory tracking, and non-contact interaction. Due to the array's omnidirectional stretchability and high linear response, the electronic skin can maintain the stability and accuracy of signal acquisition during bending, stretching, and other deformations, and can adapt to complex curved surfaces. This embodiment demonstrates the application potential of this invention in wearable devices, flexible human-computer interfaces, and intelligent prostheses.

[0054] Example 4

[0055] By encapsulating the spin valve magnetic sensing array prepared according to the method of the present invention in a biocompatible flexible material, a magnetic sensing patch that can be adhered to the human body surface can be fabricated. This patch can be used to monitor weak magnetic field changes generated by physiological activities, such as myomagnetic signals (muscle contraction), cardiac magnetoencephalogram (cardiac electrical activity), or the movement of magnetic markers in the digestive tract. Thanks to the array's high linearity, low noise, and suppression of temperature drift, a high signal-to-noise ratio physiological magnetic signal can be obtained, and its stretchable design ensures long-term comfort and signal reliability during daily activities. This embodiment provides novel device support for non-invasive, dynamic, and wearable biomedical magnetic sensing.

[0056] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be embraced within the present invention. No reference numerals in the appended diagrams should be construed as limiting the scope of the claims. Furthermore, it is clear that the word "comprising" does not exclude other elements or steps, and the singular does not exclude the plural.

[0057] However, those skilled in the art should understand that various modifications can be made to the method for fabricating the spin valve magnetic sensing array based on a Wheatstone bridge proposed in this invention without departing from the scope of the invention. Therefore, the scope of protection of this invention should be determined by the appended claims.

Claims

1. A spin valve magnetic sensing array based on a Wheatstone bridge, characterized in that, include, Flexible substrate; Multiple rigid islands are arranged in an array on the surface of the flexible substrate; Multiple magnetic sensing units, each of which includes a patterned giant magnetoresistive film disposed on a corresponding rigid island; A liquid metal circuit is disposed on the surface of the flexible substrate for connecting various magnetic sensing units; the liquid metal circuit includes a top electrode and a bottom electrode, and an isolation layer disposed at the intersection of the top electrode and the bottom electrode.

2. The spin valve magnetic sensing array based on a Wheatstone bridge according to claim 1, characterized in that, The projected area of ​​the giant magnetoresistive film on the rigid island is smaller than the area of ​​the rigid island.

3. The spin valve magnetic sensing array based on a Wheatstone bridge according to claim 1, characterized in that, It also includes a flexible printed circuit board, which is connected to the liquid metal circuit via anisotropic conductive tape.

4. The spin valve magnetic sensing array based on a Wheatstone bridge according to claim 1, characterized in that, The liquid metal circuit is made of liquid metal or silver nanowires.

5. A method for fabricating a spin valve magnetic sensing array based on a Wheatstone bridge, characterized in that, A sacrificial layer is formed on a rigid temporary substrate, and a flexible substrate is fabricated on the sacrificial layer; An array of rigid islands is formed on the flexible substrate using a photolithography process; A photoresist layer with an inverted trapezoidal sidewall Wheatstone bridge pattern is formed on the rigid island using a photolithography process; Spin valve multilayer film material is deposited on the sample with the photoresist layer, and after photoresist stripping, giant magnetoresistive film corresponding to each rigid island is obtained. Fabrication of liquid metal circuits: sequentially printing bottom electrodes through a mask, coating and curing flexible polymer insulating material at the intersection of bottom and top electrodes to form an insulating layer, and printing top electrodes again through a mask; Dissolve the sacrificial layer; The magnetic sensing array is then encapsulated to complete its fabrication.

6. The method for fabricating a spin valve magnetic sensing array based on a Wheatstone bridge according to claim 5, characterized in that, The method for depositing a spin valve multilayer film material on a sample having the photoresist layer, and then performing resist stripping to obtain the giant magnetoresistive film corresponding to each of the rigid islands includes: Spin valve multilayer films were generated on the surface of a sample with a mechanical mask attached using magnetron sputtering technology. The sample with the spin valve multilayer film generated is placed in acetone and subjected to ultrasonic treatment to achieve patterning of the spin valve multilayer film.

7. The method for fabricating a spin valve magnetic sensing array based on a Wheatstone bridge according to claim 5, characterized in that, The step of depositing a spin valve multilayer film material on a sample having the photoresist layer includes: Spin valve multilayer film material is deposited on the sample surface with the photoresist layer by magnetron sputtering, wherein a rigid mechanical mask is used to selectively deposit the spin valve multilayer film in the region where the rigid island is located.

8. The method for fabricating a spin valve magnetic sensing array based on a Wheatstone bridge according to claim 5, characterized in that, The sacrificial layer is formed using dextran, and is dissolved by soaking in deionized water.

9. An application of a spin valve magnetic sensing array based on a Wheatstone bridge, characterized in that, The spin valve magnetic sensing array based on the Wheatstone bridge as described in any one of claims 1 to 4 is applied to an electronic device, wherein the spin valve magnetic sensing array has a linear response of the output voltage signal to the magnetic field.

10. The application according to claim 9, characterized in that, When the flexible substrate is subjected to an omnidirectional tensile strain of up to 27%, the strain on the rigid island is less than 0.5%.

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