Magnetic sensor and method for manufacturing a magnetic sensor

Abstract

The application provides a magnetic sensor and a preparation method of the magnetic sensor, and relates to the technical field of semiconductor devices and processes.The method comprises the following steps: etching a first substrate to form a first protrusion; forming a second substrate on the first substrate after etching treatment, the second substrate having a first recess corresponding to the first protrusion; forming a first magnetic resistance, a second magnetic resistance, a third magnetic resistance and a fourth magnetic resistance connected in a full bridge on the second substrate, the first magnetic resistance and the third magnetic resistance being located on one side of the first recess, and the second magnetic resistance and the fourth magnetic resistance being located on the other side of the first recess; peeling off the first substrate to obtain a magnetic sensor body; and folding the magnetic sensor body along the first recess.The application realizes the folding treatment of two adjacent magnetic resistance elements by folding the magnetic sensor body along the first recess, so that the magnetic resistance units on the two adjacent bridge arms of the Wheatstone full bridge structure have opposite magnetic pinning directions, the stability of the performance of the magnetic sensor is improved, and the process is relatively simple.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor devices and processes, and particularly relates to a magnetic sensor and a preparation method of the magnetic sensor. BACKGROUND

[0002] In recent years, the Internet of Things and intelligent technology are developing rapidly, and the magnetic sensor plays an important role in the development of the Internet of Things and intelligent technology. Therefore, it is very important to ensure the performance of the magnetic sensor. The output of the magnetic sensor changes due to the change of temperature, which leads to the instability of the magnetic sensor. In order to improve the temperature stability of the magnetic sensor, it is required that the magnetoresistance units on the adjacent two bridge arms of the Wheatstone full-bridge structure in the magnetic sensor have opposite changes with the external magnetic field, which means that the adjacent two magnetoresistance units constituting the bridge arm should have opposite magnetic pinning directions.

[0003] In the prior art, the magnetoresistance units on the adjacent two bridge arms of the Wheatstone full-bridge structure in the magnetic sensor have opposite magnetic pinning directions by the following methods: the first method is a mechanical assembly method, which rotates the magnetoresistance units on the adjacent bridge arms by 180 degrees, and the magnetoresistance units are connected by wire bonding; the second method is to change the pinning direction of the magnetoresistance units on the bridge arm by local annealing through current or radiation; the third method is to deposit thin films with different structures in different regions on the same wafer to make the pinning directions opposite; and the fourth method is to bend the magnetic induction lines by the magnetic flux concentrator structure to make the directions of the external magnetic field detected by the magnetoresistance units on the adjacent bridge arms opposite. However, the above methods are difficult to control accurately and efficiently, which makes it difficult to ensure that the magnetic pinning directions of the magnetoresistance units on the adjacent two bridge arms of the Wheatstone full-bridge structure are completely opposite, and the process is complex, the preparation cost is high, the performance consistency of the magnetoresistance units is poor, the volume of the magnetic sensor is increased, and it is not conducive to miniaturization. SUMMARY

[0004] The first object of the present application is to provide a preparation method of a magnetic sensor to control the relative rotation of the magnetoresistance units by 180 degrees, so as to satisfy that the magnetoresistance units on the adjacent two bridge arms of the Wheatstone full-bridge structure have opposite magnetic pinning directions, and improve the stability of the performance of the magnetic sensor. The second object of the present application is to provide a magnetic sensor. The third object of the present application is to provide a dual-axis magnetic sensor. The fourth object of the present application is to provide a tri-axial magnetic sensor.

[0005] In order to achieve the above object, the application discloses a preparation method of a magnetic sensor, which comprises the following steps: etching a first substrate to form a first protrusion; forming a second substrate on the first substrate after the etching treatment, the second substrate having a first recess corresponding to the first protrusion; forming a first magnetoresistance, a second magnetoresistance, a third magnetoresistance and a fourth magnetoresistance in full-bridge connection on the second substrate, wherein the pinning directions of the first magnetoresistance, the second magnetoresistance, the third magnetoresistance and the fourth magnetoresistance are the same, one end of the first magnetoresistance is electrically connected with the second magnetoresistance and the fourth magnetoresistance respectively, the other end of the third magnetoresistance is electrically connected with the second magnetoresistance and the fourth magnetoresistance respectively, the first magnetoresistance and the third magnetoresistance are located on one side of the first recess, and the second magnetoresistance and the fourth magnetoresistance are located on the other side of the first recess; peeling off the first substrate to obtain a magnetic sensor body; and folding the magnetic sensor body along the first recess to make the pinning directions of the first magnetoresistance and the third magnetoresistance opposite to the pinning directions of the second magnetoresistance and the fourth magnetoresistance.

[0006] Preferably, the method further comprises: determining a folding line in the first recess; and the folding the magnetic sensor body along the first recess comprises: folding the magnetic sensor body along the folding line.

[0007] Preferably, the determining the folding line in the first recess comprises: determining the folding line at the thinnest part of the first recess.

[0008] Preferably, the thickness of the thinnest part of the first recess is less than one third of the thickness of the second substrate.

[0009] Preferably, the folding the magnetic sensor body along the folding line comprises: folding the magnetic sensor body on one side of the first recess along the folding line to above or below the magnetic sensor body on the other side of the first recess.

[0010] Preferably, the forming the first magnetoresistance, the second magnetoresistance, the third magnetoresistance and the fourth magnetoresistance in full-bridge connection on the second substrate comprises: forming bottom electrodes of the four magnetoresistances on the second substrate, the bottom electrodes comprising a first bottom electrode shared by the first magnetoresistance and the second magnetoresistance and a second bottom electrode shared by the third magnetoresistance and the fourth magnetoresistance; forming the four magnetoresistances on the bottom electrodes respectively; forming top electrodes on the four magnetoresistances respectively; forming external electrodes, the external electrodes comprising a first excitation electrode, a first output electrode, a second excitation electrode and a second output electrode, the first bottom electrode being electrically connected with the first excitation electrode, the second bottom electrode being electrically connected with the second excitation electrode, the top electrode shared by the second magnetoresistance and the third magnetoresistance being electrically connected with the first output electrode, and the top electrode shared by the first magnetoresistance and the fourth magnetoresistance being electrically connected with the second output electrode.

[0011] Preferably, the forming four bottom electrodes of magnetic resistors on the second substrate comprises: depositing a first conductive material on the second substrate; and patterning the first conductive material to form four bottom electrodes of magnetic resistors.

[0012] Preferably, the forming four bottom electrodes of magnetic resistors on the second substrate comprises: depositing a first conductive material on the second substrate; and patterning the first conductive material to form four bottom electrodes of magnetic resistors.

[0013] Preferably, the forming four bottom electrodes of magnetic resistors on the second substrate comprises: depositing a first conductive material on the second substrate; and patterning the first conductive material to form four bottom electrodes of magnetic resistors.

[0014] Preferably, the forming four bottom electrodes of magnetic resistors on the second substrate comprises: depositing a first conductive material on the second substrate; and patterning the first conductive material to form four bottom electrodes of magnetic resistors.

[0015] Preferably, the method further comprises: forming a protective layer on the top electrode.

[0016] Preferably, the forming a second substrate on the first substrate after etching comprises: forming a sacrificial layer on the first substrate after etching; and forming the second substrate on the sacrificial layer.

[0017] Preferably, the second substrate is made of a flexible material.

[0018] The application further discloses a magnetic sensor prepared by the preparation method of the magnetic sensor.

[0019] The application further discloses a dual-axis magnetic sensor comprising two stacked magnetic sensors, at least one of which is prepared by the preparation method of the magnetic sensor; wherein the magnetic sensitive directions of the two magnetic sensors are arranged orthogonally in a plane.

[0020] The application further discloses a three-axis magnetic sensor comprising a first magnetic sensor, a second magnetic sensor and a third magnetic sensor stacked together, at least one of which is prepared by the preparation method of the magnetic sensor; wherein the magnetic sensitive directions of the first magnetic sensor and the second magnetic sensor are arranged orthogonally in a plane, and the magnetic sensitive direction of the third magnetic sensor is arranged orthogonally to the magnetic sensitive directions of the first magnetic sensor and the second magnetic sensor out of the plane.

[0021] The magnetic sensor prepared by the embodiment of the application realizes the folding processing of the adjacent two magnetoresistance elements by folding the magnetic sensor body along the first recess, better controls the relative rotation of the adjacent two magnetoresistance elements by 180 degrees, and thus can better meet the requirement that the magnetoresistance units on the adjacent two bridge arms of the Wheatstone full-bridge structure have opposite magnetic pinning directions, and improve the stability of the performance of the magnetic sensor. In addition, the magnetoresistance elements are formed by one process, the magnetoresistance characteristics are the same, and the consistency of the magnetoresistance is ensured. Moreover, compared with the existing methods of adding an extra device, depositing by partition, radiation, and current, the above folding method has relatively simple process and accurate control, and thus simplifies the preparation process of the magnetic sensor. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0023] Figure 1 Fig. 1 shows a flowchart of one specific embodiment of a preparation method of a magnetic sensor of the application;

[0024] Figure 2 Fig. 2 shows a flowchart of forming a second substrate on a first substrate after etching in one specific embodiment of a preparation method of a magnetic sensor of the application;

[0025] Figure 3 Fig. 3 shows a flowchart of forming a first magnetoresistance, a second magnetoresistance, a third magnetoresistance and a fourth magnetoresistance in full-bridge connection on a second substrate in one specific embodiment of a preparation method of a magnetic sensor of the application;

[0026] Figure 4 Fig. 4 shows a circuit diagram of the first magnetoresistance, the second magnetoresistance, the third magnetoresistance and the fourth magnetoresistance in full-bridge connection in one specific embodiment of a preparation method of a magnetic sensor of the application;

[0027] Figure 5 Fig. 5 shows a flowchart of forming a top electrode on the four magnetoresistances respectively in one specific embodiment of a preparation method of a magnetic sensor of the application;

[0028] Figure 6 Fig. 6 shows another flowchart of one specific embodiment of a preparation method of a magnetic sensor of the application;

[0029] Figure 7 Fig. 7 shows a third flowchart of one specific embodiment of a preparation method of a magnetic sensor of the application;

[0030] Figure 8 Fig. 1 shows a structure diagram of a first substrate with a first protrusion in one embodiment of the preparation method of the magnetic sensor according to the present application;

[0031] Figure 9 Fig. 2 shows a structure diagram of the device after depositing a sacrificial layer in one embodiment of the preparation method of the magnetic sensor according to the present application;

[0032] Figure 10 Fig. 3 shows a structure diagram of the device after forming a solidification layer on the sacrificial layer in one embodiment of the preparation method of the magnetic sensor according to the present application;

[0033] Figure 11 Fig. 4 shows a structure diagram of the device after forming a bottom electrode and four magnetoresistances on the bottom electrode on the second substrate in one embodiment of the preparation method of the magnetic sensor according to the present application;

[0034] Figure 12 Fig. 5 shows a structure diagram of the device after forming a dielectric layer on the four magnetoresistances and the bottom electrode in one embodiment of the preparation method of the magnetic sensor according to the present application;

[0035] Figure 13 Fig. 6 shows a structure diagram of the device after forming a top electrode and an external electrode on the dielectric layer in one embodiment of the preparation method of the magnetic sensor according to the present application;

[0036] Figure 14 Fig. 7 shows a structure diagram of the device after forming a protective layer on the top electrode in one embodiment of the preparation method of the magnetic sensor according to the present application;

[0037] Figure 15 Fig. 8 shows a structure diagram of the magnetic sensor body in one embodiment of the preparation method of the magnetic sensor according to the present application;

[0038] Figure 16 Fig. 9 shows a structure diagram of the magnetic sensor in one embodiment of the preparation method of the magnetic sensor according to the present application. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0040] In the prior art, the magnetic resistance units on the adjacent two bridge arms of the Wheatstone full-bridge structure in the magnetic sensor have opposite magnetic pinning directions by the following way:

[0041] The first method is a mechanical assembly method, which rotates the adjacent bridge arms of the magnetoresistance unit by 180 degrees, and the magnetoresistance units are connected by wire bonding. However, it is difficult to ensure the accuracy of the rotation angle, and thus the magnet pinning directions of the magnetoresistance units on the adjacent two bridge arms of the Wheatstone full bridge structure cannot be completely opposite.

[0042] The second method is to change the pinning direction of the magnetoresistance unit on the bridge arm by local annealing through current or radiation, but this method is inefficient and complex, and is not suitable for mass production.

[0043] The third method is to deposit different structures of thin films in different regions on the same wafer to make their pinning directions opposite, which requires two times of thin film deposition, and the process difficulty is increased, the cost is higher, and it is difficult to ensure the consistency of the magnetic resistance performance of the two thin film structures.

[0044] The fourth method is to bend the magnetic induction lines by the magnetic flux concentrator structure, so that the external magnetic field directions detected by the adjacent bridge arms of the magnetoresistance unit are opposite. It can be seen that this method needs additional devices, which increases the cost and makes the process complex.

[0045] From the above, it can be seen that the existing method for realizing that the magnetoresistance units on the adjacent two bridge arms of the Wheatstone full bridge structure in the magnetic sensor have completely opposite magnetic pinning directions cannot well control the relative rotation of the magnetoresistance units by 180 degrees, and thus cannot meet the requirement that the magnetoresistance units on the adjacent two bridge arms of the Wheatstone full bridge structure have opposite magnetic pinning directions, so that the stability of the performance of the magnetic sensor is low, and the process is relatively complex.

[0046] In view of the problems of the existing magnetic sensor, the present application proposes a preparation method of a magnetic sensor, which folds the magnetic sensor body on one side of the first recess to the magnetic sensor body on the other side of the first recess along the folding line, better controls the relative rotation of the adjacent two magnetoresistance units by 180 degrees, and thus can better meet the requirement that the magnetoresistance on the adjacent two bridge arms of the Wheatstone full bridge structure has opposite pinning directions, improves the stability of the performance of the magnetic sensor, and the folding method is relatively simple compared with the existing methods of current, radiation, partition deposition and adding additional devices, thereby simplifying the preparation process of the magnetic sensor.

[0047] In order to solve the above problems, according to one aspect of the present application, the embodiment discloses a preparation method of a magnetic sensor. Figure 1 As shown in the figure, the preparation method of the magnetic sensor comprises:

[0048] S100: etching a first substrate to form a first protrusion.

[0049] The first protrusion in the embodiment of the present application can be of any shape. Preferably, the shape of the first protrusion can be trapezoidal.

[0050] Preferably, the first substrate can be monocrystalline silicon, and the first substrate is etched to form a convex interface with high flatness and precisely controllable shape by anisotropic wet etching.

[0051] S200: forming a second substrate on the first substrate after the etching process, the second substrate having a first recess corresponding to the first convexity.

[0052] Preferably, the second substrate is made of flexible material, and the material of the second substrate is not limited in the embodiments of the present application, but any flexible material that can be used as a substrate is within the protection scope of the present application. For example, the second substrate can be polyimide (PI).

[0053] By setting the material of the second substrate as flexible material, the subsequent folding operation is facilitated, thereby simplifying the preparation method of the magnetic sensor.

[0054] In addition, the embodiments of the present application do not limit whether the first recess is horizontal or whether there is a thinnest part inside. If the first recess is horizontal, the thickness of the first recess is less than the first preset thickness. If the first recess is not horizontal, there is a thinnest part inside, and the thickness of the thinnest part of the first recess is less than the second preset thickness. The first preset thickness and the second preset thickness can be the same or different, and the specific values can be set according to the flexibility of the first substrate and the specific application scenarios, which are not limited in the embodiments of the present application. For example, the first preset thickness and the second preset thickness are the same, and are one third of the thickness of the second substrate.

[0055] S300: forming a first magnetic resistance, a second magnetic resistance, a third magnetic resistance and a fourth magnetic resistance connected in full-bridge on the second substrate.

[0056] In the embodiments, the pinning directions of the first magnetic resistance, the second magnetic resistance, the third magnetic resistance and the fourth magnetic resistance are the same, one end of the first magnetic resistance is electrically connected with the second magnetic resistance and the fourth magnetic resistance respectively, the other end of the third magnetic resistance is electrically connected with the second magnetic resistance and the fourth magnetic resistance respectively, the first magnetic resistance is adjacent to the second magnetic resistance, and the third magnetic resistance is adjacent to the fourth magnetic resistance.

[0057] The two adjacent magnetic resistances are distributed on both sides of the first recess, and further, the first magnetic resistance and the third magnetic resistance are located on one side of the first recess, and the second magnetic resistance and the fourth magnetic resistance are located on the other side of the first recess, according to the above adjacent relationship (i.e. the first magnetic resistance and the second magnetic resistance are adjacent, and the third magnetic resistance and the fourth magnetic resistance are adjacent). For example, the first magnetic resistance and the third magnetic resistance are located on the left side of the first recess, and the second magnetic resistance and the fourth magnetic resistance are located on the right side of the first recess, or the first magnetic resistance and the third magnetic resistance are located on the right side of the first recess, and the second magnetic resistance and the fourth magnetic resistance are located on the left side of the first recess.

[0058] S400: peeling off the first substrate to obtain a magnetic sensor body.

[0059] S500: fold the magnetic sensor body along the first recess, so that the pinning directions of the first magnetic resistance and the third magnetic resistance are opposite to the pinning directions of the second magnetic resistance and the fourth magnetic resistance.

[0060] Specifically, the magnetic sensor body on the left side of the first recess is folded upwards along the first recess to the upper side of the magnetic sensor body on the right side of the first recess, so that the pinning directions of the two adjacent magnetic resistances are opposite, and further, the pinning directions of the first magnetic resistance, the third magnetic resistance and the second magnetic resistance, the fourth magnetic resistance are opposite.

[0061] Specifically, when the first magnetic resistance and the third magnetic resistance are located on the left side of the first recess, and the second magnetic resistance and the fourth magnetic resistance are located on the right side of the first recess, the magnetic sensor body on the left side of the first recess can be folded upwards along the first recess to the upper side of the magnetic sensor body on the right side of the first recess.

[0062] The present application realizes the folding processing of the two adjacent magnetic resistance elements by folding the magnetic sensor body along the first recess, and better controls the relative rotation of the two adjacent magnetic resistance elements by 180 degrees, so that the stability of the performance of the magnetic sensor can be better satisfied.

[0063] The magnetic resistance element is formed by one process, and the magnetic resistance characteristics are the same, which ensures the consistency of the magnetic resistance.

[0064] Compared with the existing methods of adding extra devices through current, radiation, partition deposition and partition deposition, the process is relatively simple, thereby simplifying the preparation process of the magnetic sensor. Moreover, since the second substrate is made of flexible material, the magnetic sensor body can be folded more conveniently, and the preparation process of the magnetic sensor is further simplified.

[0065] As an optional embodiment, as shown in Figure 2 S200 can specifically include:

[0066] S210: forming a sacrificial layer on the first substrate after etching treatment.

[0067] The material of the sacrificial layer is not specifically limited in the embodiment of the present application, but the material of the sacrificial layer in the prior art is within the protection scope of the embodiment of the present application, for example, the material of the sacrificial layer can be silicon oxide, organic polymer, etc.

[0068] When the sacrificial layer is formed on the first substrate, S400 includes: peeling off the first substrate and the sacrificial layer to obtain the magnetic sensor body.

[0069] S220: spin-coating PI on the sacrificial layer and curing to obtain the second substrate.

[0070] The step of spin-coating PI on the sacrificial layer and solidifying to form a second substrate includes: spin-coating a PI solution on the sacrificial layer and heating to solidify a PI solid film, which serves as the second substrate.

[0071] It is worth mentioning that the bottom electrode and the top electrode are functionally equivalent and serve to connect the four magnetic resistances, and the positions of the bottom electrode and the top electrode can be interchanged, that is, if the bottom electrode is set first, then the top electrode is set subsequently, or if the top electrode is set first, then the bottom electrode is set subsequently. In the preferred embodiment, as shown in FIG. 3, the bottom electrode is set first and then the top electrode is set, and the S300 specifically can include: Figure 3

[0072] S310: Forming a bottom electrode of the four magnetic resistances on the second substrate, the bottom electrode including a first bottom electrode and a second bottom electrode, the first bottom electrode being shared by the first magnetic resistance and the second magnetic resistance, and the second bottom electrode being shared by the third magnetic resistance and the fourth magnetic resistance.

[0073] Specifically, a first conductive material is deposited on the second substrate, and the first conductive material is patterned to form the bottom electrode of the four magnetic resistances. The patterning process herein includes photolithography, etching, etc.

[0074] S320: Forming the four magnetic resistances on the bottom electrode, respectively. Specifically, a magnetic material is deposited on the bottom electrode, and the magnetic material is etched at positions corresponding to the bottom electrode to form the first magnetic resistance, the second magnetic resistance, the third magnetic resistance, and the fourth magnetic resistance.

[0075] S330: Forming a top electrode on the four magnetic resistances, respectively.

[0076] S340: Forming an external electrode. The external electrode includes a first excitation electrode V DD , a second excitation electrode GND, a first output electrode V+, and a second output electrode V-. The first bottom electrode is electrically connected to the first excitation electrode V DD , the second bottom electrode is electrically connected to the second excitation electrode GND, the top electrode shared by the second magnetic resistance and the third magnetic resistance is electrically connected to the first output electrode V+, and the top electrode shared by the first magnetic resistance and the fourth magnetic resistance is electrically connected to the second output electrode V-.

[0077] Thus, the circuit of the first magnetic resistance, the second magnetic resistance, the third magnetic resistance, and the fourth magnetic resistance connected in a full bridge is as shown in FIG. 4. Figure 4 Figure 4 In the preferred embodiment, as shown in FIG. 3, the bottom electrode is set first and then the top electrode is set, and the S330 specifically can include:

[0078] In the preferred embodiment, as shown in FIG. 3, the bottom electrode is set first and then the top electrode is set, and the S330 specifically can include: Figure 5

[0079] ​​​S3310: A dielectric layer is deposited on the first, second, third, and fourth magnetoresistors and the bottom electrode of the full-bridge connection.

[0080] In this embodiment, the dielectric layer serves an insulating function to prevent unconnected components from becoming electrically connected. The dielectric layer is made of insulating materials, such as silicon nitride and silicon dioxide.

[0081] S3320: Patterning is performed on the dielectric layer above the first magnetoresistive, second magnetoresistive, third magnetoresistive, and fourth magnetoresistive to form a through hole.

[0082] S3330: A second conductive material is deposited on the dielectric layer forming the via, and a top electrode is formed on the second conductive material at positions corresponding to the four magnetoresistances.

[0083] In an optional embodiment, S340 includes: depositing a third conductive material on the second conductive material, and etching on the third conductive material to form an external electrode.

[0084] The first, second, and third conductive materials described above can be selected according to the actual application scenario, and the embodiments of the present invention do not impose any restrictions on this. For example, the first, second, and third conductive materials can be the same, and can be metal, conductive plastic, conductive rubber, or conductive composite materials.

[0085] To address the above problems, according to another aspect of the present invention, this embodiment discloses a method for fabricating a magnetic sensor. For example... Figure 6 As shown, the method for fabricating the magnetic sensor includes steps S100 to S400, S600, and S700. In this embodiment, steps S100 to S400 are... Figure 1 The corresponding implementation methods are similar and will not be described in detail here.

[0086] S600: Determine the fold line within the first recess.

[0087] If there is a weakest point within the first recess, then the fold line is determined at the thinnest point of the first recess. If there is no weakest point within the first recess, then the fold line is determined at any position within the first recess, preferably at the middle position of the first recess.

[0088] S700: Fold the magnetic sensor body along the fold line. Specifically, fold the magnetic sensor body on one side of the first recess along the fold line to the top or bottom of the magnetic sensor body on the other side of the first recess.

[0089] In the embodiment, when the first magnetic reluctance and the third magnetic reluctance are located on the left side of the first recess, and the second magnetic reluctance and the fourth magnetic reluctance are located on the right side of the first recess, the magnetic sensor body on the left side of the first recess can be folded upward along the folding line to the upper side of the magnetic sensor body on the right side of the first recess. The magnetic sensor body on the right side of the first recess can also be folded downward along the folding line to the lower side of the magnetic sensor body on the left side of the first recess, but at this time, the first recess needs to be large enough to ensure that the second magnetic reluctance is below the first magnetic reluctance and the fourth magnetic reluctance is below the third magnetic reluctance when folded downward.

[0090] In the embodiment, the folding line is determined at the thinnest part of the first recess, so that the thickness of the substrate at the folding line is thinned, or the folding line is determined at the middle position of the first recess, so that it is easier to fold the magnetic sensor body along the folding line, the design of high-precision alignment is realized, the relative rotation of 180 degrees of the two adjacent magnetic reluctance elements is more accurately controlled, the magnetic resistance units on the two adjacent bridge arms of the Wheatstone full-bridge structure have opposite magnetic pinning directions, and the stability of the performance of the magnetic sensor is further improved.

[0091] In the embodiment, the magnetic reluctance elements are formed by one process, the magnetic reluctance characteristics are the same, and the consistency of the magnetic reluctance is ensured.

[0092] Compared with the existing methods of using current, radiation, partition deposition and adding additional devices, the above folding method has a relatively simple process, thereby simplifying the preparation process of the magnetic sensor. Moreover, since the second substrate is made of a flexible material, the magnetic sensor body can be folded more conveniently, and the preparation process of the magnetic sensor is further simplified.

[0093] The application will be further described below through a specific example. As shown in Figure 7 In the specific example, the bottom electrode is prepared first and then the top electrode is prepared, and the preparation method of the magnetic sensor includes the following steps:

[0094] S100: etching the first substrate to form a first protrusion. Taking the shape of the first protrusion as a trapezoid, the first substrate 100 with the first protrusion is as shown in Figure 8 .

[0095] S210: forming a sacrificial layer 200 on the first substrate after etching treatment, and the device after depositing the sacrificial layer 200 is as shown in Figure 9 .

[0096] S220: spin-coating PI on the sacrificial layer and solidifying to obtain a second substrate 300, and the device after forming the second substrate 300 on the sacrificial layer is as shown in Figure 10 .

[0097] S310: forming four bottom electrodes 400 of magnetic reluctance on the second substrate, that is, forming four bottom electrodes of magnetic reluctance on the solidified layer of the second substrate.

[0098] S320: Form four magnetic resistances 500 on the bottom electrode respectively. The device after forming the bottom electrode 400 and the four magnetic resistances 500 on the bottom electrode on the second substrate 300 is as shown in FIG. 3C. Figure 11

[0099] S3310: Deposit a dielectric layer 600 on the first magnetic resistance, the second magnetic resistance, the third magnetic resistance, the fourth magnetic resistance and the bottom electrode in full-bridge connection, and the device after forming the dielectric layer 600 on the four magnetic resistances and the bottom electrode is as shown in FIG. 3E. Figure 12

[0100] S3320: Pattern the dielectric layer above the first magnetic resistance, the second magnetic resistance, the third magnetic resistance and the fourth magnetic resistance to form a via hole.

[0101] S3330: Deposit a second conductive material on the dielectric layer 600 in which the via hole is formed, and pattern the second conductive material to form a top electrode 700.

[0102] S340: Form an external electrode 800. The device after forming the top electrode and the external electrode on the dielectric layer is as shown in FIG. 3G. Figure 13

[0103] S800: Form a protective layer 900 on the top electrode, and the device after forming the protective layer on the top electrode is as shown in FIG. 8A. Figure 14

[0104] The protective layer can be a flexible protective layer, and the material of the protective layer can include polyimide, polyurethane, polypropylene, composite polymer, etc. Through the protective layer, the circuit is protected from the influence of the external environment (such as water vapor, foreign impurities and mechanical damage, etc.), thereby playing a protective role for the magnetic sensor.

[0105] S400: Peel off the first substrate and the sacrificial layer to obtain a magnetic sensor body, and the magnetic sensor body is as shown in FIG. 4A. Figure 15

[0106] S600: Determine a folding line in the first recess.

[0107] S700: Fold the magnetic sensor body along the folding line to obtain a magnetic sensor, and the magnetic sensor is as shown in FIG. 7A. Figure 16

[0108] ​​​​​​The application realizes high-precision satisfaction of the magnetoresistance units on the adjacent two bridge arms of the Wheatstone full-bridge structure having opposite magnetic pinning directions by folding the magnetic sensor body along the folding line, improves the stability of the magnetic sensor performance, protects the circuit from the influence of the external environment through the protective layer, thereby protecting the magnetic sensor and improving the durability of the magnetic sensor.

[0109] The magnetoresistance element of the embodiment of the application is formed by one process, has the same magnetoresistance characteristics, and ensures the consistency of the magnetoresistance.

[0110] Compared with the existing methods of current, radiation, partition deposition and additional devices, the folding method is relatively simple in process, thereby simplifying the preparation process of the magnetic sensor.

[0111] The application further provides a magnetic sensor prepared by the magnetic field sensor preparation method, as shown in the figure. Figure 16

[0112] The application further provides a dual-axis magnetic sensor comprising a stacked first magnetic sensor and a second magnetic sensor, and at least one magnetic sensor is prepared by the magnetic sensor preparation method.

[0113] The application further provides a tri-axis magnetic sensor comprising a stacked first magnetic sensor, a second magnetic sensor and a third magnetic sensor, and at least one magnetic sensor is prepared by the magnetic sensor preparation method.

[0114] ​It should also be noted that the terms "comprising," "including," and any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises a... " does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the recited element.

[0115] Each of the embodiments in the present specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other. Each of the embodiments focuses on the difference from other embodiments. In particular, for the system embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the part of the description of the method embodiments.

[0116] The above only describes the embodiments of the present application and is not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the scope of claims of the present application.

Claims

1. A method of manufacturing a magnetic sensor, characterized by, The preparation method comprises: etching a first substrate to form a first protrusion; forming a second substrate on the first substrate after etching, the second substrate having a first recess corresponding to the first protrusion; forming a first magnetoresistance, a second magnetoresistance, a third magnetoresistance and a fourth magnetoresistance in full-bridge connection on the second substrate, wherein the first magnetoresistance, the second magnetoresistance, the third magnetoresistance and the fourth magnetoresistance have the same pinning direction, one end of the first magnetoresistance is electrically connected with the second magnetoresistance and the fourth magnetoresistance respectively, the other end of the third magnetoresistance is electrically connected with the second magnetoresistance and the fourth magnetoresistance respectively, the first magnetoresistance and the third magnetoresistance are located on one side of the first recess, and the second magnetoresistance and the fourth magnetoresistance are located on the other side of the first recess; peeling off the first substrate to obtain a magnetic sensor body; folding the magnetic sensor body along the first recess to make the pinning direction of the first magnetoresistance and the third magnetoresistance opposite to the pinning direction of the second magnetoresistance and the fourth magnetoresistance.

2. The production method according to claim 1, wherein The method further comprises: determining a folding line in the first recess; the folding the magnetic sensor body along the first recess comprises: folding the magnetic sensor body along the folding line.

3. The production method according to claim 2, wherein the determining the folding line in the first recess comprises: determining the folding line at the thinnest part of the first recess.

4. The production method according to claim 3, wherein The thickness of the thinnest part of the first recess is less than one third of the thickness of the second substrate.

5. The production method according to any one of claims 2 to 4, wherein the folding the magnetic sensor body along the folding line comprises: folding the magnetic sensor body on one side of the first recess to above or below the magnetic sensor body on the other side of the first recess along the folding line.

6. The production method according to any one of claims 1 to 4, wherein the forming the first magnetoresistance, the second magnetoresistance, the third magnetoresistance and the fourth magnetoresistance in full-bridge connection on the second substrate comprises: forming bottom electrodes of the four magnetoresistances on the second substrate, the bottom electrodes comprising a first bottom electrode shared by the first magnetoresistance and the second magnetoresistance and a second bottom electrode shared by the third magnetoresistance and the fourth magnetoresistance; forming the four magnetoresistances on the bottom electrodes respectively; forming top electrodes on the four magnetoresistances respectively; forming external electrodes, the external electrodes comprising a first excitation electrode, a first output electrode, a second excitation electrode and a second output electrode, the first bottom electrode being electrically connected with the first excitation electrode, the second bottom electrode being electrically connected with the second excitation electrode, the top electrode shared by the second magnetoresistance and the third magnetoresistance being electrically connected with the first output electrode, and the top electrode shared by the first magnetoresistance and the fourth magnetoresistance being electrically connected with the second output electrode.

7. The production method according to claim 6, wherein the forming the bottom electrodes of the four magnetoresistances on the second substrate comprises: depositing a first conductive material on the second substrate; performing patterning on the first conductive material to form the bottom electrodes of the four magnetoresistances.

8. The production method according to claim 6, wherein the forming the four magnetoresistances on the bottom electrodes respectively comprises: depositing a magnetic material on the second substrate; performing patterning on the magnetic material at positions corresponding to the bottom electrodes to form the first magnetoresistance, the second magnetoresistance, the third magnetoresistance and the fourth magnetoresistance.

9. The production method according to claim 6, wherein the forming the top electrodes on the four magnetoresistances respectively comprises: depositing a dielectric layer on the first magnetic reluctance, the second magnetic reluctance, the third magnetic reluctance, the fourth magnetic reluctance and the bottom electrode in full-bridge connection; forming a top electrode on the dielectric layer.

10. The production method according to claim 9, wherein The forming a top electrode on the dielectric layer comprises: patterning the dielectric layer above the first magnetic reluctance, the second magnetic reluctance, the third magnetic reluctance, the fourth magnetic reluctance to form a via hole; depositing a second conductive material on the dielectric layer with the via hole; patterning the second conductive material to form the top electrode.

11. The production method according to claim 10, wherein The method further comprises: forming a protective layer on the top electrode.

12. The production method according to any one of claims 1 to 4, wherein The forming a second substrate on the first substrate after etching comprises: forming a sacrificial layer on the first substrate after etching; forming the second substrate on the sacrificial layer.

13. The production method according to any one of claims 1 to 4, wherein The material of the second substrate is a flexible material.

14. A magnetic sensor, characterized by Prepared by the method of any one of claims 1-13.

15. A dual-axis magnetic sensor, characterized by Comprising two stacked magnetic sensors, at least one of the magnetic sensors is prepared by the method of any one of claims 1-13. Wherein the magnetic sensitive directions of the two magnetic sensors are orthogonally arranged.

16. A three-axis magnetic sensor, characterized by Comprising stacked first, second and third magnetic sensors, at least one of the magnetic sensors is prepared by the method of any one of claims 1-13. Wherein the magnetic sensitive directions of the first and second magnetic sensors are orthogonally arranged in-plane, the magnetic sensitive direction of the third magnetic sensor is out-of-plane and orthogonally arranged with the magnetic sensitive directions of the first and second magnetic sensors.

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