A method for manufacturing a high-sensitivity out-of-plane magnetic field sensor

Abstract

This invention relates to the field of sensor technology, specifically a method and apparatus for manufacturing a high-sensitivity out-of-plane magnetic field sensor. The out-of-plane magnetic field sensor comprises a substrate consisting of a base, a seed layer, a non-magnetic material layer, a magnetic material layer, and a protective layer, arranged in an overlapping manner from bottom to top. The non-magnetic material layer is used to ensure strong initial perpendicular magnetic anisotropy between adjacent magnetic material layers. The advantages of this invention are: simple and low-cost fabrication method; clear, flat interfaces and good adhesion of the fabricated multilayer film structure; and excellent initial perpendicular magnetic anisotropy. It also features a small size, facilitating integration and reducing the Z-axis volume. Furthermore, this out-of-plane magnetic field sensor further reduces perpendicular magnetic anisotropy by annealing the ferromagnetic layer, thereby improving the sensor's sensitivity.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to a method for manufacturing a high-sensitivity out-of-plane magnetic field sensor. Background Technology

[0002] Traditional magnetic field sensors are mostly sensitive to in-plane detection. To achieve out-of-plane magnetic field detection, the following schemes are mainly adopted: Based on the tunneling magnetoresistive effect: Tunneling magnetoresistive sensors with perpendicular magnetic anisotropy can effectively detect out-of-plane magnetic fields, but the large coercive field leads to low sensitivity. Based on the Hall effect: Hall sensors based on semiconductor materials are widely used for out-of-plane magnetic field detection, but their low sensitivity (below 2000 V / A / T) and low operating frequency (not exceeding MHz) hinder further development. Furthermore, Hall sensors based on non-magnetic metal materials have a very weak Hall effect due to their high carrier density, making them difficult to apply in devices. In contrast, magnetic metals not only exhibit the Hall effect but also an anomalous Hall effect. Generally, the anomalous Hall effect is several orders of magnitude larger than the normal Hall effect, resulting in a larger Hall effect in magnetic metals. However, current sensors based on the anomalous Hall effect have limited sensitivity due to their large saturation field. In-plane magnetic field sensors employ mechanical assembly: vertically encapsulating the in-plane sensor to detect out-of-plane magnetic fields increases the sensor's size. All three methods have significant drawbacks, greatly limiting out-of-plane magnetic field detection. Summary of the Invention

[0003] In view of the problems existing in the above or prior art, the present invention is proposed.

[0004] Therefore, the purpose of this invention is to provide a method for manufacturing a high-sensitivity out-of-plane magnetic field sensor, which can solve the problem of low out-of-plane sensitivity of existing magnetic field sensors.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for manufacturing a high-sensitivity out-of-plane magnetic field sensor, comprising: ultrasonically cleaning a substrate with acetone, alcohol, and deionized water respectively, drying it, and baking it in an oven; applying photoresist to the substrate, unspinning the photoresist using a spin coater, and then placing the substrate in an oven to cure the photoresist; exposing the photoresist layer to ultraviolet light through a mask with a first predefined pattern, and then developing it with a developer to remove excess photoresist, leaving a first predefined pattern on the substrate; and sequentially growing a seed layer and a non-magnetic layer on the treated substrate. A substrate is formed by adding a conductive material layer, a magnetic material layer, and a protective layer. The first layer of photoresist is removed, and photoresist is dropped onto the substrate on which the thin film has been grown. The photoresist is then spread using a spin coater, and the substrate is placed in an oven to cure the photoresist. The photoresist layer is exposed to ultraviolet light through a mask with a second predefined pattern, and then developed using a developer to remove excess photoresist, leaving a second predefined pattern on the substrate. Conductive metal is grown on the treated substrate using magnetron sputtering thin film growth technology. The second layer of photoresist is removed, and annealing technology is used to reduce the vertical magnetic anisotropy of the sensor.

[0006] As a preferred embodiment of the manufacturing method of the high-sensitivity out-of-plane magnetic field sensor of the present invention, the substrate is ultrasonically cleaned with acetone, alcohol and deionized water for 5 minutes respectively, then dried by blowing with N2, and then placed in an oven at 115°C for 20 minutes.

[0007] As a preferred embodiment of the manufacturing method of the high-sensitivity out-of-plane magnetic field sensor of the present invention, the substrate is deposited sequentially by magnetron sputtering or electron beam evaporation to obtain a multilayer film structure, and the obtained multilayer film structure is processed into an out-of-plane magnetic field detector with a Hall bar structure by photolithography and lift-off processes.

[0008] In a preferred embodiment of the manufacturing method of the high-sensitivity out-of-plane magnetic field sensor of the present invention, the Hall bar structure out-of-plane magnetic field detector formed by processing the multilayer film structure of the substrate is a cross-shaped Hall Bar structure arranged sequentially from bottom to top.

[0009] As a preferred embodiment of the manufacturing method of the high-sensitivity out-of-plane magnetic field sensor of the present invention, the HallBar structure is prepared by photolithography and lift-off techniques, such that the area of ​​the central rectangle of the structure is 100×100μm2~1000×1000μm2, and the area of ​​the overlapping part of the center of the cross-shaped structure is 5×5μm2~100×100μm2.

[0010] In a preferred embodiment of the manufacturing method of the high-sensitivity out-of-plane magnetic field sensor of the present invention, after photoresist is dropped onto a substrate on which a thin film has been grown, the substrate is first rotated at a speed of 600 rpm for 10 seconds on a spin coater to make the photoresist cover the substrate, and then rotated at a speed of 4000 rpm for 40 seconds to make the photoresist gradually thinner and ensure uniform thickness.

[0011] In a preferred embodiment of the manufacturing method of the high-sensitivity out-of-plane magnetic field sensor of the present invention, the vertical magnetic anisotropy intensity of the out-of-plane magnetic field sensor is related to the thickness of the non-magnetic material layer and the thickness of the magnetic material layer during sensor fabrication. The thickness of the non-magnetic material layer is controlled between approximately 2-3 nm, and the thickness of the magnetic material layer is controlled between approximately 0.6-0.7 nm.

[0012] In a preferred embodiment of the manufacturing method of the high-sensitivity out-of-plane magnetic field sensor of the present invention, the intensity of the perpendicular magnetic anisotropy of the out-of-plane magnetic field sensor is reduced by annealing. The annealing temperature is related to the thickness of the magnetic material, and when the thickness of the magnetic material layer is about 0.6-0.7 nm, the temperature range is 150℃ to 250℃.

[0013] In a preferred embodiment of the manufacturing method of the high-sensitivity out-of-plane magnetic field sensor of the present invention, the coercivity of the out-of-plane magnetic field sensor gradually decreases as the annealing temperature increases. When the coercivity of the out-of-plane magnetic field sensor approaches 0, the temperature reaches the optimal temperature T1. At this point, if the annealing temperature is further increased, the coercivity of the out-of-plane magnetic field sensor remains unchanged, and the magnetization saturation field of the out-of-plane magnetic field sensor increases as the temperature increases.

[0014] As a preferred embodiment of the manufacturing method of the high-sensitivity out-of-plane magnetic field sensor of the present invention, the out-of-plane magnetic field sensor, after annealing, has both in-plane and out-of-plane magnetic domains, exhibiting a weak perpendicular magnetic anisotropy.

[0015] The beneficial effects of this invention are as follows: This invention employs magnetron sputtering or electron beam evaporation to deposit a multilayer film structure on a substrate, and then uses photolithography and lift-off processes to fabricate the obtained multilayer film structure into an out-of-plane magnetic field detector with a Hall bar structure. This fabrication method is simple and low-cost. The fabricated multilayer film structure has a clear, flat interface with good adhesion and excellent initial perpendicular magnetic anisotropy. Furthermore, because the out-of-plane magnetic field detector is on the order of micrometers and its sensitivity direction is out-of-plane, its small size facilitates integration. The out-of-plane sensitivity allows for integration with in-plane sensitive sensors to achieve a three-dimensional magnetic field sensor, reducing the Z-axis volume. In addition, this out-of-plane magnetic field detector further reduces perpendicular magnetic anisotropy through annealing of the ferromagnetic layer, improving the sensor's sensitivity. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0017] Figure 1 This is a schematic diagram of the vertical anisotropy state in the initial state after the sensor is fabricated, which is part of the manufacturing method for a high-sensitivity out-of-plane magnetic field sensor.

[0018] Figure 2 This is a schematic diagram of the magnetic domain arrangement after the sensor, which is annealed to become weakly vertically anisotropic, in the manufacturing method of a high-sensitivity out-of-plane magnetic field sensor.

[0019] Figure 3 This is a schematic diagram of the overall structure of an out-of-plane magnetic field sensor, illustrating the manufacturing method of a high-sensitivity out-of-plane magnetic field sensor.

[0020] Figure 4 This is a schematic diagram of the structure of an out-of-plane magnetic field sensor material used in the manufacturing method of a high-sensitivity out-of-plane magnetic field sensor.

[0021] Figure 5 This is a schematic diagram of the structure of an out-of-plane magnetic field sensor material used in the manufacturing method of a high-sensitivity out-of-plane magnetic field sensor. Detailed Implementation

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0023] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0024] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0025] Example 1

[0026] Reference Figures 1-3 The first embodiment of the present invention provides a method for manufacturing a high-sensitivity out-of-plane magnetic field sensor, which includes the specific structure of the out-of-plane magnetic field sensor and its generation method.

[0027] Specifically, the out-of-plane magnetic field sensor includes a substrate, which is divided into a base, a seed layer, a non-magnetic material layer, a magnetic material layer, and a protective layer, which are arranged in an overlapping manner from bottom to top.

[0028] Non-magnetic material layers are used to give adjacent magnetic material layers strong initial perpendicular magnetic anisotropy.

[0029] Furthermore, the substrate is one of Si(100) / SiO2 ordinary substrate, MgO single crystal substrate, SrTiO3 single crystal substrate and ferroelectric substrate, and the ferroelectric substrate is one of BaTiO3, PZT and PMN-PT.

[0030] Furthermore, the substrate is deposited sequentially with a seed layer, a non-magnetic material layer, a magnetic material layer, and a protective layer using magnetron sputtering or electron beam evaporation to obtain a multilayer film structure. The obtained multilayer film structure is then processed into an out-of-plane magnetic field detector with a Hallbar structure using photolithography and lift-off processes.

[0031] Furthermore, the Hallbar structure out-of-plane magnetic field detector, fabricated from the multilayer film structure of the substrate, consists of cross-shaped Hallbar structures arranged sequentially from bottom to top.

[0032] Furthermore, out-of-plane magnetic field sensors utilize the anomalous Hall effect to read Hall resistance.

[0033] Specifically, the sensor sensitivity is calculated as S = dVxy / dH. According to this formula, the sensor sensitivity can be effectively improved by reducing the sensor's saturation magnetic field H.

[0034] Furthermore, the thickness of the magnetic metal and the non-magnetic metal can be controlled to achieve perpendicular magnetic anisotropy under critical conditions (when the thickness of the magnetic metal continues to decrease, the perpendicular magnetic anisotropy disappears).

[0035] By further reducing the perpendicular magnetic anisotropy through magnetic annealing, the magnetic metal film of the sensor has both in-plane and out-of-plane magnetic domains, thereby effectively reducing the out-of-plane saturation field of the sensor and improving its sensitivity.

[0036] In summary, this invention employs magnetron sputtering or electron beam evaporation to deposit a multilayer film structure on a substrate, and then uses photolithography and lift-off processes to fabricate the obtained multilayer film structure into an out-of-plane magnetic field detector with a Hall bar structure. This fabrication method is simple and low-cost, and the prepared multilayer film structure has a clear, flat interface with good adhesion and excellent initial perpendicular magnetic anisotropy. Furthermore, because the out-of-plane magnetic field detector is on the order of micrometers and its sensitivity direction is out-of-plane, its small size facilitates integration. The out-of-plane sensitivity allows for integration with in-plane sensitive sensors to achieve a three-dimensional magnetic field sensor, reducing the Z-axis volume. In addition, the out-of-plane magnetic field detector further reduces perpendicular magnetic anisotropy through annealing of the ferromagnetic layer, improving the sensor's sensitivity.

[0037] Example 2

[0038] Reference Figures 1-3 The second embodiment of the present invention provides a method for manufacturing a high-sensitivity out-of-plane magnetic field sensor, which can improve the sensitivity of the sensor and reduce the excitation current of the sensor by weakening the vertical magnetic anisotropy of the magnetic sensor functional layer.

[0039] Specifically, the HallBar structure is fabricated using photolithography and lift-off techniques, resulting in a central rectangle with an area of ​​100×100μm2 to 1000×1000μm2, and the overlapping portion of the cross-shaped structure with an area of ​​5×5μm2 to 100×100μm2.

[0040] Furthermore, the vertical magnetic anisotropy of the out-of-plane magnetic field sensor is related to the thickness of the non-magnetic material layer and the thickness of the magnetic material layer during sensor fabrication. The thickness of the non-magnetic material layer is controlled between approximately 2-3 nm, and the thickness of the magnetic material layer is controlled between approximately 0.6-0.7 nm, so that the sensor has a critical state of vertical magnetic anisotropy.

[0041] It should be noted that the stronger the perpendicular magnetic anisotropy, the larger the saturation magnetization field, and the lower the corresponding sensitivity. Therefore, reducing the perpendicular magnetic anisotropy can effectively improve the sensor sensitivity. However, when the perpendicular magnetic anisotropy is reduced to the in-plane easy axis, the sensor output will drop to 0. Therefore, it is necessary to ensure the highest sensor sensitivity within a suitable range.

[0042] Furthermore, the intensity of the perpendicular magnetic anisotropy of the out-of-plane magnetic field sensor is reduced using annealing technology. The annealing temperature is related to the thickness of the magnetic material; when the thickness of the magnetic material layer is approximately 0.6-0.7 nm, the temperature range is 150℃ to 250℃.

[0043] Furthermore, the coercive field of the out-of-plane magnetic field sensor gradually decreases as the annealing temperature increases. When the coercive field of the out-of-plane magnetic field sensor approaches 0, the temperature reaches the optimal temperature T1. At this point, if the annealing temperature is further increased, the coercive field of the out-of-plane magnetic field sensor remains unchanged, causing the magnetization saturation field of the out-of-plane magnetic field sensor to increase with the increase of temperature.

[0044] It should be noted that the optimal temperature value is determined by testing the anomalous Hall voltage and observing the out-of-plane saturation field. The out-of-plane saturation field first decreases and then increases with increasing temperature, and the optimal temperature corresponds to the minimum value of the coercive field. The value of the coercive field corresponds to the thickness of the magnetic layer, and different coercive fields correspond to different optimal temperatures, which correspond to the magnitude of the perpendicular magnetic anisotropy field mentioned earlier.

[0045] Furthermore, such as Figure 2 As shown, after annealing, the out-of-plane magnetic field sensor has both in-plane and out-of-plane magnetic domains, exhibiting a weak perpendicular magnetic anisotropy.

[0046] It should be noted that before annealing, if Figure 1 As shown, the out-of-plane magnetic field sensor exhibits strong vertical anisotropy in its initial state.

[0047] In summary, this invention employs magnetron sputtering or electron beam evaporation to deposit a multilayer film structure on a substrate, and then uses photolithography and lift-off processes to fabricate the obtained multilayer film structure into an out-of-plane magnetic field detector with a Hall bar structure. This fabrication method is simple and low-cost, and the prepared multilayer film structure has a clear, flat interface with good adhesion and excellent initial perpendicular magnetic anisotropy. Furthermore, because the out-of-plane magnetic field detector is on the order of micrometers and its sensitivity direction is out-of-plane, its small size facilitates integration. The out-of-plane sensitivity allows for integration with in-plane sensitive sensors to achieve a three-dimensional magnetic field sensor, reducing the Z-axis volume. In addition, the out-of-plane magnetic field detector further reduces perpendicular magnetic anisotropy through annealing of the ferromagnetic layer, improving the sensor's sensitivity.

[0048] Example 3

[0049] Reference Figures 4-5 This is the third embodiment of the present invention, which provides specific steps for manufacturing a high-sensitivity out-of-plane magnetic field sensor.

[0050] Specifically, such as Figure 4As shown, a high-sensitivity out-of-plane magnetic field sensor based on weak perpendicular magnetic anisotropy includes a substrate material, a seed layer, a non-magnetic material layer, a magnetic material layer, a protective layer, and an electrode material. The sensor adopts a cross-shaped structure, with the seed layer, non-magnetic material layer, magnetic material layer, and protective layer sequentially deposited on the substrate. The non-magnetic layer is composed of a heavy metal material with a thickness of 2 nm to 5 nm, and the magnetic material layer is composed of a perpendicular magnetization film. Both the seed layer and the protective layer are made of one of Ta, Ti, or Ru.

[0051] Furthermore, the substrate is one of Si(100) / SiO2 ordinary substrate, MgO single crystal substrate, SrTiO3 single crystal substrate and ferroelectric substrate, wherein the ferroelectric substrate is one of BaTiO3, PZT and PMN-PT.

[0052] Furthermore, the vertical magnetization film of the sensor is one of the following: a vertically magnetized Co / Pt monolayer film, a Co / Pd monolayer film, and a CoFeB / MgO film.

[0053] Specifically, a substrate is provided and ultrasonically cleaned for 5 minutes each with acetone, alcohol, and deionized water, then dried with N2 and baked at 115°C for 20 minutes in an oven.

[0054] Furthermore, using APR-3510P photoresist, after the photoresist is dropped onto the substrate, it is first rotated at 600 rpm for 10 seconds on a spin coater to make the photoresist cover the substrate, and then rotated at 4000 rpm for 40 seconds to make the photoresist thickness uniform. The photoresist used is a positive photoresist.

[0055] Furthermore, the substrate with spin-coated photoresist is placed in an oven and heated at 115°C for 20 minutes to allow the photoresist to fully cure.

[0056] Furthermore, the first photoresist layer is exposed to ultraviolet light through a mask with a first predefined pattern. The ultraviolet light passes through the mask and irradiates the photoresist layer. Under the action of ultraviolet light, the polymer chains in the photoresist in the unmasked parts will break, making the photoresist easier to dissolve. The mask is a transparent or semi-transparent template containing the desired pattern, usually made of quartz glass, with a layer of chromium (or other material) as an opaque layer to block ultraviolet light.

[0057] Furthermore, the photoresist layer is immersed in a developing solution to develop it, dissolving the photoresist in the exposed area and removing the excess photoresist from the wafer, leaving only the unexposed photoresist on the substrate as the first predefined pattern.

[0058] Furthermore, using magnetron sputtering thin film growth technology, a thin film is grown on the prepared substrate, consisting of a seed layer, a non-magnetic material layer, a magnetic material layer, and a protective layer.

[0059] It should be noted that magnetron sputtering is a physical vapor deposition method. Its basic principle is as follows: an orthogonal magnetic field and electric field are applied between the target (cathode) and the anode. An inert gas (usually Ar) is then introduced into a vacuum chamber. Ar atoms are bombarded by electrons accelerated by the electric field, producing Ar ions. Simultaneously, electrons are generated at the cathode under the influence of the electric field. These electrons fly towards the anode, but are confined by the magnetic field, forming a high-concentration plasma region near the target surface. Finally, a large number of Ar ions, under the influence of the electric field, fly at high speed towards and bombard the target surface, sputtering out a large number of target atoms, which are then deposited on the substrate to form a thin film.

[0060] Electron beam evaporation is a physical vapor deposition method. Its basic principle is to use accelerated electrons to bombard the surface of a target material, converting the electrons' kinetic energy into heat energy to evaporate the target material (placed in a water-cooled crucible), which then melts and deposits onto a substrate. Electron guns are classified as direct-fire, annular, and E-type. Electron beam evaporation is characterized by its extremely high energy density, reaching up to 10⁹ W / cm², and heating temperatures of 3000–6000 °C. It can evaporate refractory metals or compounds, enabling the preparation of high-purity thin films.

[0061] Furthermore, the photoresist left after development is removed by a stripping process. This process requires the selection of a chemical stripper that can dissolve or soften the positive photoresist. Generally, it can be removed by organic solvents (such as acetone, isopropanol, etc.) or specific chemical strippers.

[0062] Furthermore, photoresist is dropped onto the substrate on which the thin film has been grown, and a spin coater is first rotated at 600 rpm for 10 seconds to make the photoresist uniformly cover the substrate, and then rotated at 4000 rpm for 40 seconds to make the photoresist thickness uniformly thinner.

[0063] Furthermore, the substrate with spin-coated photoresist is placed in an oven and heated at 115°C for 20 minutes to allow the photoresist to fully cure.

[0064] Furthermore, the second photoresist layer is exposed to ultraviolet light through a mask with a second predefined pattern. The ultraviolet light passes through the mask and irradiates the photoresist layer. Under the action of ultraviolet light, the polymer chains in the photoresist in the unmasked parts will break, making the photoresist easier to dissolve.

[0065] Furthermore, the photoresist layer is immersed in a developing solution to develop it, dissolving the photoresist in the exposed area and removing the excess photoresist from the wafer, leaving only the unexposed photoresist on the substrate as a second predefined pattern.

[0066] Furthermore, conductive metals are grown on the prepared substrate using magnetron sputtering thin film growth technology.

[0067] Furthermore, the photoresist left after development is removed through a stripping process.

[0068] Furthermore, annealing technology is used to reduce the vertical magnetic anisotropy of the sensor. As the annealing temperature increases, the coercive field of the sensor gradually decreases. When the temperature reaches the optimal annealing temperature T1, the coercive field of the sensor approaches 0. If the annealing temperature continues to increase, the coercive field of the sensor remains unchanged, but the saturation field will increase with the increase of temperature, affecting the sensitivity of the sensor.

[0069] Furthermore, the sensitivity of the out-of-plane magnetic field sensor is determined by comparing the saturation field, such as... Figure 5 As shown, the two exhibit an inverse proportional relationship. The saturation field of existing sensors is typically in the hundreds of Oe, while the saturation field of this invention is only 2 Oe. This means that the sensor can detect even small changes in the magnetic field. In other words, the magnetization direction of the sensor can be reversed under the influence of a small external magnetic field, making it more sensitive to changes in the external magnetic field and thus significantly improving its sensitivity.

[0070] In summary, this invention employs magnetron sputtering or electron beam evaporation to deposit a multilayer film structure on a substrate, and then uses photolithography and lift-off processes to fabricate the obtained multilayer film structure into an out-of-plane magnetic field detector with a Hall bar structure. This fabrication method is simple and low-cost, and the prepared multilayer film structure has a clear, flat interface with good adhesion and excellent initial perpendicular magnetic anisotropy. Furthermore, this out-of-plane magnetic field detector further reduces perpendicular magnetic anisotropy through annealing of the ferromagnetic layer, improving the sensor's sensitivity. The increased sensitivity means the sensor can resolve smaller magnetic field changes, thereby improving measurement resolution. Simultaneously, the low-saturation field sensor can detect a wider range of magnetic field strengths and responds more rapidly to magnetic field changes.

[0071] It is important to note that the constructions and arrangements of this application shown in several different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, those who consult this disclosure will readily understand that many modifications are possible (such as variations in installation arrangement, use of materials, color, orientation, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in this application. For example, an element shown as integrally formed may be composed of multiple parts or elements, the position of the element may be inverted or otherwise changed, and the nature or number or position of the discrete elements may be altered or changed. Therefore, all such modifications are intended to be included within the scope of the invention. The order or sequence of any process or method steps may be changed or rearranged according to alternative embodiments. In the claims, any "support plus function" clause is intended to cover the structure performing the function described herein, and not only structurally equivalent but also equivalent in structure. Other substitutions, modifications, alterations, and omissions may be made in the design, operation, and arrangement of the exemplary embodiments without departing from the scope of the invention. Therefore, the invention is not limited to the particular embodiments but extends to a variety of modifications that still fall within the scope of the appended claims.

[0072] Furthermore, in order to provide a concise description of exemplary embodiments, not all features of actual embodiments may be omitted.

[0073] It should be understood that numerous specific implementation decisions can be made during the development of any practical implementation, such as in any engineering or design project. Such development efforts may be complex and time-consuming, but for those of ordinary skill in the art who benefit from this disclosure, the development effort will be a routine task in design, manufacturing, and production without requiring extensive experimentation.

[0074] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for manufacturing a high-sensitivity out-of-plane magnetic field sensor, characterized in that: include, The substrate was ultrasonically cleaned with acetone, alcohol and deionized water respectively, dried and then placed in an oven to bake. Photoresist is dropped onto the substrate, and the photoresist is spread out using a spin coater. The substrate is then placed in an oven to cure the photoresist. The photoresist layer is exposed to ultraviolet light through a mask with a first predefined pattern, and then developed with a developer to remove excess photoresist, leaving the first predefined pattern on the substrate. A seed layer, a non-magnetic material layer, a magnetic material layer, and a protective layer are sequentially grown on the prepared substrate to form a substrate. Remove the first layer of photoresist, and drop photoresist onto the substrate on which the thin film has been grown. Spin the photoresist using a spin coater, and then place the substrate into an oven to cure the photoresist. The photoresist layer is exposed to ultraviolet light through a mask with a second predefined pattern, and then developed with a developer to remove excess photoresist, leaving the second predefined pattern on the substrate. Conductive metals are grown on a prepared substrate using magnetron sputtering thin film growth technology. The second layer of photoresist is removed, and annealing is used to reduce the vertical magnetic anisotropy of the sensor. The substrate is deposited sequentially with a seed layer, a non-magnetic material layer, a magnetic material layer, and a protective layer using magnetron sputtering or electron beam evaporation to obtain a multilayer film structure. The obtained multilayer film structure is then processed into an out-of-plane magnetic field detector with a Hall bar structure using photolithography and lift-off processes.

2. The manufacturing method of the high-sensitivity out-of-plane magnetic field sensor as described in claim 1, characterized in that: The substrate was ultrasonically cleaned with acetone, alcohol and deionized water for 5 minutes each, then dried with N2, and then placed in an oven at 115°C for 20 minutes.

3. The manufacturing method of the high-sensitivity out-of-plane magnetic field sensor as described in claim 2, characterized in that: The Hall bar structure of the substrate, fabricated from a multilayer film structure, forms an out-of-plane magnetic field detector in the shape of a cross, arranged sequentially from bottom to top.

4. The manufacturing method of the high-sensitivity out-of-plane magnetic field sensor as described in claim 3, characterized in that: The HallBar structure was fabricated using photolithography and lift-off techniques, resulting in a central rectangular area of ​​100 × 100 μm. 2 ~1000×1000μm 2 Furthermore, the area of ​​the overlapping portion at the center of the cross-shaped structure is 5×5μm. 2 ~100×100μm 2 .

5. The method for manufacturing a high-sensitivity out-of-plane magnetic field sensor as described in claim 4, characterized in that: After photoresist is dropped onto the substrate on which the thin film has been grown, the substrate is first rotated at 600 rpm for 10 seconds on a spin coater to cover the substrate with photoresist, and then rotated at 4000 rpm for 40 seconds to gradually thin the photoresist and ensure uniform thickness.

6. The method for manufacturing a high-sensitivity out-of-plane magnetic field sensor as described in claim 5, characterized in that: The vertical magnetic anisotropy intensity of the out-of-plane magnetic field sensor is related to the thickness of the non-magnetic material layer and the thickness of the magnetic material layer during sensor fabrication. The thickness of the non-magnetic material layer is controlled between 2-3 nm, and the thickness of the magnetic material layer is controlled between 0.6-0.7 nm.

7. The method for manufacturing a high-sensitivity out-of-plane magnetic field sensor as described in claim 6, characterized in that: The intensity of the vertical magnetic anisotropy of the out-of-plane magnetic field sensor is reduced by annealing. The annealing temperature is related to the thickness of the magnetic material. When the thickness of the magnetic material layer is 0.6-0.7 nm, the temperature range is 150℃~250℃.

8. The method for manufacturing a high-sensitivity out-of-plane magnetic field sensor as described in claim 7, characterized in that: The coercive field of the out-of-plane magnetic field sensor gradually decreases as the annealing temperature increases. When the coercive field of the out-of-plane magnetic field sensor approaches 0, the temperature reaches the optimal temperature T1. At this point, if the annealing temperature is further increased, the coercive field of the out-of-plane magnetic field sensor remains unchanged, causing the magnetization saturation field of the out-of-plane magnetic field sensor to increase with the increase of temperature.

9. The method for manufacturing a high-sensitivity out-of-plane magnetic field sensor as described in claim 8, characterized in that: After annealing, the out-of-plane magnetic field sensor has both in-plane and out-of-plane magnetic domains, exhibiting a weak perpendicular magnetic anisotropy.

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