TMR magnetic sensor and manufacturing method therefor

Abstract

A TMR magnetic sensor and a manufacturing method therefor. The TMR magnetic sensor comprises: a substrate (110), comprising an inclined structure, an inclined surface of the inclined structure being inclined between a second direction and a third direction; and, arranged on the substrate (110), first magnetic field sensitive areas (120) and second magnetic field sensitive areas (130), the first magnetic field sensitive areas (120) and the second magnetic field sensitive areas (130) each being formed by magnetic tunnel junctions (140) connected in series or in parallel or in a series-parallel combination mode. The magnetic tunnel junctions (140) located in the first magnetic field sensitive areas (120) are arranged on a flat surface of the substrate (110) and have a pinning direction in a first direction; the magnetic tunnel junctions (140) located in the second magnetic field sensitive areas (130) are at least partially arranged on the inclined surface of the inclined structure, and the magnetic tunnel junctions (140) arranged on the inclined surface of the inclined structure have a pinning direction along the inclined surface of the inclined structure, the first direction, the second direction and the third direction being perpendicular to each other in pairs, and the third direction also being perpendicular to the flat surface of the substrate (110).

Description

TMR magnetic sensor and preparation method thereof

[0001] This application claims priority to the Chinese patent application filed with the Patent Office of China on January 31, 2024, with application number 202410140454.2, and with the invention name “TMR magnetic sensor and its preparation method”, and claims priority to the Chinese patent application filed with the Patent Office of China on October 23, 2024, with application number 202411486993.8, and with the invention name “TMR magnetic sensor and its preparation method”, the entire contents of which are incorporated into this application by reference. Technical Field

[0002] The present invention relates to the technical field of magnetic field sensing devices, and in particular to a TMR magnetic sensor and a preparation method thereof. Background Art

[0003] With the development of science and technology and the continuous progress of society, more and more types of magnetic sensors are appearing in people's daily work and life. TMR (Tunnel Magnetoresistance Effect) magnetic sensors are magnetic sensitive elements that use the tunnel magnetoresistance effect. External magnetic fields can cause the resistance of TMR magnetoresistance elements to change, thereby detecting external magnetic fields. However, the distribution of external magnetic fields is usually three-dimensional, and TMR magnetoresistance elements can only sense magnetic fields in a plane, which is difficult to meet the needs of measuring three-axis magnetic fields. Summary of the Invention

[0004] According to various embodiments of the present application, a TMR magnetic sensor and a method for manufacturing the same are provided.

[0005] A TMR magnetic sensor, comprising:

[0006] a substrate, the substrate comprising an inclined structure, wherein an inclined surface of the inclined structure is inclined between a second direction and a third direction;

[0007] A first magnetic field sensitive region and a second magnetic field sensitive region are provided on the substrate, wherein the first magnetic field sensitive region and the second magnetic field sensitive region are both composed of magnetic tunnel junctions connected in series or in parallel or in a combination of series and parallel connections; the magnetic tunnel junction located in the first magnetic field sensitive region is arranged in the plane of the substrate and has a pinning direction along a first direction; the magnetic tunnel junction located in the second magnetic field sensitive region is at least partially arranged on the inclined surface of the inclined structure, and the magnetic tunnel junction arranged on the inclined surface of the inclined structure has a pinning direction along the inclined surface of the inclined structure;

[0008] The first direction, the second direction and the third direction are perpendicular to each other, and the third direction is also perpendicular to the plane of the substrate.

[0009] A method for preparing a TMR magnetic sensor, comprising:

[0010] forming an inclined structure on the substrate, wherein an inclined surface of the inclined structure is inclined between a second direction and a third direction;

[0011] A magnetic tunnel junction is formed on the substrate; the substrate is provided with a first magnetic field sensitive region and a second magnetic field sensitive region, and the first magnetic field sensitive region and the second magnetic field sensitive region are both composed of the magnetic tunnel junctions connected in series, in parallel, or in a combination of series and parallel; the magnetic tunnel junction located in the first magnetic field sensitive region is arranged in the plane of the substrate and has a pinning direction along a first direction; the magnetic tunnel junction located in the second magnetic field sensitive region is at least partially arranged on the inclined surface of the inclined structure, and the magnetic tunnel junction arranged on the inclined surface of the inclined structure has a pinning direction along the inclined surface of the inclined structure;

[0012] The first direction, the second direction and the third direction are perpendicular to each other, and the third direction is also perpendicular to the plane of the substrate.

[0013] The details of one or more embodiments of the present application are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0015] FIG1 is a schematic structural diagram of a TMR magnetic sensor according to an embodiment;

[0016] FIG2 is a schematic diagram of the cross-sectional structure of the TMR magnetic sensor along line AA′ in FIG1 ;

[0017] FIG3 is a schematic diagram of the cross-sectional structure of the TMR magnetic sensor along line BB′ in FIG1 ;

[0018] FIG4 is an equivalent circuit diagram of a full-bridge structure composed of an X-axis magnetic tunnel junction array in one embodiment;

[0019] FIG5 is a schematic diagram of the distribution and circuit connection of an X-axis magnetic tunnel junction array in one embodiment;

[0020] FIG6 is a schematic diagram of the arrangement of Y-axis / Z-axis magnetic tunnel junctions in one embodiment;

[0021] FIG7 is an equivalent circuit diagram of a full-bridge structure composed of a Y-axis / Z-axis magnetic tunnel junction array in one embodiment;

[0022] FIG8 is a schematic diagram of the distribution and circuit connection of the Y-axis / Z-axis magnetic tunnel junction array in one embodiment;

[0023] FIG9 is a schematic structural diagram of a TMR magnetic sensor in another embodiment;

[0024] FIG10 is a schematic diagram of the cross-sectional structure of the TMR magnetic sensor along line AA′ in FIG9 ;

[0025] FIG11 is a schematic diagram of the cross-sectional structure of the TMR magnetic sensor along line BB′ in FIG9 ;

[0026] FIG12 is an equivalent circuit diagram of a full-bridge structure composed of a Y-axis magnetic tunnel junction array in one embodiment;

[0027] FIG13 is a schematic diagram showing the distribution and circuit connection of a Y-axis magnetic tunnel junction array in one embodiment;

[0028] FIG14 is a schematic diagram of the arrangement of a Z-axis magnetic tunnel junction in one embodiment;

[0029] FIG15 is an equivalent circuit diagram of a full-bridge structure composed of a Z-axis magnetic tunnel junction array in one embodiment;

[0030] FIG16 is a schematic diagram showing the distribution and circuit connection of a Z-axis magnetic tunnel junction array in one embodiment;

[0031] 17 to 31 are schematic structural diagrams of a TMR magnetic sensor fabrication process according to one embodiment;

[0032] 17-23 and 32-43 are schematic structural diagrams of the preparation process of a TMR magnetic sensor in another embodiment. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0034] In one embodiment, as shown in Figures 1 to 3, a TMR magnetic sensor is provided, comprising a substrate 110, and a first magnetic field sensitive region 120 and a second magnetic field sensitive region 130 disposed on the substrate 110. The substrate 110 includes a tilted structure, wherein the tilted surface of the tilted structure tilts between a second direction and a third direction. The first magnetic field sensitive region 120 and the second magnetic field sensitive region 130 are each composed of magnetic tunnel junctions 140 connected in series, in parallel, or in a combination of series and parallel. The magnetic tunnel junctions 140 located in the first magnetic field sensitive region 120 are arranged in the plane of the substrate 110 and have a pinning direction along the first direction. The magnetic tunnel junctions 140 located in the second magnetic field sensitive region 130 are at least partially arranged on the tilted surface of the tilted structure, and the magnetic tunnel junctions 140 arranged on the tilted surface of the tilted structure have a pinning direction along the tilted surface of the tilted structure. The first direction, the second direction, and the third direction are perpendicular to each other, and the third direction is also perpendicular to the plane of the substrate 110.

[0035] Specifically, the first direction and the second direction can be the X-axis direction and the Y-axis direction, respectively, or can be the Y-axis direction and the X-axis direction, respectively. The third direction is the Z-axis direction, and the plane of the substrate 110 is the XY plane. For ease of understanding, the following description is based on the example that the first direction, the second direction, and the third direction are the X-axis direction, the Y-axis direction, and the Z-axis direction, respectively.

[0036] The magnetic tunnel junction 140 generally comprises a free layer, a tunnel barrier layer, and a pinned layer. Changes in the external magnetic field cause the magnetization direction of the free layer to change. When the magnetization direction of the free layer is positively parallel to the pinning direction of the pinned layer, the magnetic tunnel junction 140 is in a low-resistance state. When the magnetization direction of the free layer is antiparallel to the pinning direction of the pinned layer, the magnetic tunnel junction 140 is in a high-resistance state. Thus, the magnetic field component of the external magnetic field parallel to the pinning direction can cause the magnetization direction of the free layer to change, and this parallel state with the pinning direction of the pinned layer can cause the resistance of the magnetic tunnel junction 140 to change. By connecting the magnetic tunnel junctions 140 in series, parallel, or a combination of series and parallel, an electrical signal corresponding to the component of the external magnetic field in the pinning direction can be output.

[0037] The magnetic tunnel junction 140 of the first magnetic field sensitive region 120 is arranged on the plane of the substrate 110 and has a pinning direction along the X-axis. Therefore, the first magnetic field sensitive region 120 can be used to detect the magnetic field in the X-axis direction.

[0038] The magnetic tunnel junction 140 of the second magnetic field sensitive region 130 may be partially disposed on the plane of the substrate 110 and partially disposed on the inclined surface of the inclined structure; the magnetic tunnel junction 140 of the second magnetic field sensitive region 130 may also be entirely disposed on the inclined surface of the inclined structure. Because the inclined surface of the inclined structure is inclined between the Y-axis direction and the Z-axis direction, and the magnetic tunnel junction 140 disposed on the inclined surface of the inclined structure has a pinning direction along the inclined surface, the magnetic tunnel junction 140 disposed on the inclined surface of the inclined structure can sense an external magnetic field whose magnetic field direction is parallel to the inclined surface of the inclined structure. This external magnetic field whose magnetic field direction is parallel to the inclined surface of the inclined structure has a magnetic field component along the Y-axis direction and a magnetic field component along the Z-axis direction. Based on this, the magnetic tunnel junction 140 of the second magnetic field sensitive region 130 can detect magnetic fields in both the Y-axis and Z-axis directions.

[0039] The TMR magnetic sensor of this embodiment is provided with a substrate 110 having an inclined structure, wherein the inclined surface of the inclined structure is inclined between the second direction and the third direction, and the magnetic tunnel junction 140 of the first magnetic field sensitive region 120 is arranged on the plane of the substrate, and the magnetic tunnel junction 140 of the second magnetic field sensitive region 130 is at least partially arranged on the inclined surface of the inclined structure. The magnetic tunnel junction 140 of the first magnetic field sensitive region 120 has a pinning direction along the first direction, and the magnetic tunnel junction 140 arranged on the inclined surface of the inclined structure has a pinning direction along the inclined surface of the inclined structure. As a result, the first magnetic field sensitive region 120 can detect the magnetic field in the X-axis direction, and the second magnetic field sensitive region 130 can detect the magnetic field in the Y-axis and Z-axis directions. That is, the TMR magnetic sensor of this embodiment can realize the detection of three-axis magnetic fields.

[0040] The substrate 110 may include a substrate 112. The substrate 112 may include a CMOS wafer layer and a CMOS signal layer provided on the CMOS wafer layer. The CMOS wafer layer is integrated with an integrated circuit consisting of a plurality of MOS tubes, which can process the analog signals generated by the first magnetic field sensitive area 120 and the second magnetic field sensitive area 130 in response to the external magnetic field to obtain digital signals. The CMOS signal layer can realize functions such as receiving analog signals and outputting digital signals. The CMOS signal layer can be in the form of a metal layer, an integrated circuit layer, etc., wherein the metal layer can be a copper layer, an aluminum layer, a copper alloy layer, or an aluminum alloy layer. By integrating the TMR magnetic sensor with the substrate 112 having the CMOS wafer layer and the CMOS signal layer, the TMR magnetic sensor can eliminate the need for an additional integrated chip for signal processing, which is conducive to reducing the package size of the TMR magnetic sensor.

[0041] Furthermore, the substrate 112 may also include a protective layer disposed on the CMOS signal layer to protect the CMOS signal layer. The material of the protective layer may be silicon oxide (SiO2) or aluminum oxide (AlO x )wait.

[0042] The inclined structure of the substrate 110 may be a groove or a protrusion. Accordingly, the inclined surface of the inclined structure is the inclined surface of the groove or the inclined surface of the protrusion.

[0043] The substrate 110 may further include a first passivation layer 114 disposed on the substrate 112, and the inclined structure is disposed on the first passivation layer 114. The material of the first passivation layer 114 may be silicon oxide (SiO2) or aluminum oxide (AlO x ) etc. A flat first passivation layer 114 may be first formed on the substrate 112, and then a groove may be formed on the first passivation layer 114 by etching; or a flat first passivation layer 114 may be first formed on the substrate 112, and then a protrusion may be formed on the first passivation layer 114 by etching, deposition, or bonding.

[0044] The magnetic tunnel junctions 140 located in the first magnetic field sensitive region 120 can be arranged in an array, and the magnetic tunnel junctions 140 located in the second magnetic field sensitive region 130 can also be arranged in an array. By adopting an array layout, the layout can be made more compact, which is conducive to reducing the package size of the TMR magnetic sensor.

[0045] The magnetic tunnel junction 140 is disposed on the first passivation layer 114. Specifically, the magnetic tunnel junction 140 located in the first magnetic field sensitive region 120 is arranged on the plane of the first passivation layer 114; the magnetic tunnel junction 140 located in the second magnetic field sensitive region 130 is at least partially arranged on the inclined surface of the groove or protrusion.

[0046] A first metal layer may be provided on the side of the magnetic tunnel junction 140 close to the substrate 110, and a second metal layer may be provided on the side of the magnetic tunnel junction 140 away from the substrate 110. The first metal layer and the second metal layer are used to connect the magnetic tunnel junctions 140 in series to form a magnetoresistive unit, for series / parallel connection between the magnetoresistive units, and also for connecting the magnetoresistive unit to the power supply end or the ground setting, and transmitting the output signal (analog signal) of the bridge composed of the magnetoresistive units to the substrate 110.

[0047] 2 and 3 , the TMR magnetic sensor may further include a second passivation layer 180. The material of the second passivation layer 180 may be the same as that of the first passivation layer 114. The second passivation layer 180 covers the magnetic tunnel junction 140, serves as an insulating layer, and protects the magnetic tunnel junction 140.

[0048] As shown in Figures 1 to 3, the TMR magnetic sensor also includes a coil 150 disposed on the substrate 110. The coil 150 is a multi-turn planar coil that is used to reset each magnetic tunnel junction 140 in the first magnetic field sensitive area 120 and the second magnetic field sensitive area 130 when power is applied, thereby reducing the noise of the TMR magnetic sensor, improving detection accuracy, and reducing cross-axis interference and hysteresis.

[0049] Specifically, the portion of the coil 150 that transmits current along the X-axis direction is disposed corresponding to the first magnetic field sensitive region 120 ; the portion of the coil 150 that transmits current along the Y-axis direction is disposed corresponding to the second magnetic field sensitive region 130 . When energized, the coil 150 can generate a magnetic field perpendicular to the direction of the current. That is, the portion of the coil 150 that transmits current along the X-axis direction can generate a magnetic field in the Y-axis direction, resetting the magnetization direction of the free layer of the magnetic tunnel junction 140 in the first magnetic field sensitive region 120 so that the magnetization direction is along the Y-axis direction. The portion of the coil 150 that transmits current along the Y-axis direction can generate a magnetic field in the X-axis direction, resetting the magnetization direction of the free layer of the magnetic tunnel junction 140 in the second magnetic field sensitive region 130 so that the magnetization direction is along the X-axis direction.

[0050] As shown in Figure 1, the current in the coil 150 can be clockwise or counterclockwise. In addition, since the coil 150 is a planar coil composed of multiple turns of winding wire, the two parts of the coil 150 that are relatively arranged along the Y-axis have currents transmitted along the X-axis, and the two parts of the coil 150 that are relatively arranged along the X-axis have currents transmitted along the Y-axis. In combination with the above-mentioned correspondence between the first magnetic field sensitive area 120, the second magnetic field sensitive area 130 and the direction of current transmission in the coil 150, and in order to make the layout more compact and effectively utilize the reset function of the coil 150, the number of the first magnetic field sensitive areas 120 is two, distributed along the Y-axis, and the number of the second magnetic field sensitive areas 130 is two, distributed along the X-axis, and distributed on both sides of the axis where the two first magnetic field sensitive areas 120 are located. In this way, the portion of the coil 150 that transmits current along the positive direction (+X) of the X-axis and the portion that transmits current along the negative direction (-X) of the Y-axis each correspond to a first magnetic field sensitive region 120, and the portion that transmits current along the positive direction (+Y) of the Y-axis and the portion that transmits current along the negative direction (-Y) of the Y-axis each correspond to a second magnetic field sensitive region 130. After the coil 150 is arranged on the substrate 110, energizing the coil 150 generates a magnetic field component perpendicular to the direction of the current. The magnetic field components generated by the coil 150 generate magnetic field directions in the positive and negative directions of the Y-axis in the first magnetic field sensitive region 120, and in the positive and negative directions of the X-axis in the second magnetic field sensitive region 130. After energizing the coil 150, the portions with different current directions can be used to reset the magnetic tunnel junctions 140 in the two first magnetic field sensitive regions 120 and the two second magnetic field sensitive regions 130, thereby determining the initial magnetization direction of the free layer of the magnetic tunnel junction 140. This operation is simple and quick.

[0051] The coil 150 can be arranged above or below the magnetic tunnel junction 140. When the coil 150 is arranged below the magnetic tunnel junction 140, at least a portion of the CMOS signal layer can be used as the coil 150. When the coil 150 is arranged above the magnetic tunnel junction 140, a metal layer can be provided on the second passivation layer 180 and etched to form the coil 150.

[0052] As shown in Figures 4 and 5, a portion of the magnetic tunnel junctions 140 located in the first magnetic field sensitive region 120 has a pinning direction along the positive direction (+X) of the X-axis, while another portion has a pinning direction along the negative direction (-X) of the X-axis. A portion of the magnetic tunnel junctions 140 with a pinning direction along the positive direction (+X) of the X-axis are connected in series to form a magnetoresistive unit R11, while another portion is connected in series to form a magnetoresistive unit R13. A portion of the magnetic tunnel junctions 140 with a pinning direction along the negative direction (-X) of the X-axis are connected in series to form a magnetoresistive unit R12, while another portion is connected in series to form a magnetoresistive unit R14. The pinning direction of the magnetic tunnel junctions 140 can be determined by the annealing magnetic field. Specifically, the magnetic tunnel junctions 140 constituting the magnetoresistive units R11 and R13 are annealed in the positive direction of the X-axis, while the magnetic tunnel junctions 140 constituting the magnetoresistive units R12 and R14 are annealed in the negative direction of the X-axis. Magnetic tunnel junctions 140 that need to be annealed in the same direction can be arranged in the same region. For example, the magnetic tunnel junctions 140 constituting magnetoresistive units R11 and R13 can be arranged in the same region, while the magnetic tunnel junctions 140 constituting magnetoresistive units R12 and R14 can be arranged in another region. Based on other requirements, such as facilitating circuit connection or magnetic reset between magnetoresistive units, magnetic tunnel junctions 140 that need to be annealed in different directions can also be arranged in the same region. For example, the magnetic tunnel junctions 140 constituting magnetoresistive units R11 and R14 can be arranged in the same region, while the magnetic tunnel junctions 140 constituting magnetoresistive units R12 and R13 can be arranged in another region. When annealing in different directions is required in the same region, local laser annealing can be used.

[0053] The magnetoresistance units R11 and R14 have initial free layer magnetization directions in the positive direction of the Y-axis, while the magnetoresistance units R12 and R13 have initial free layer magnetization directions in the negative direction of the Y-axis. By disposing the magnetic tunnel junctions 140 constituting the magnetoresistance units R11 and R14 in the portion of the coil 150 that transmits current in the positive direction (+X) of the X-axis, and disposing the magnetic tunnel junctions 140 constituting the magnetoresistance units R12 and R13 in the portion of the coil 150 that transmits current in the negative direction (-X) of the X-axis, when the coil 150 is energized, the magnetization directions of the free layers of the magnetic tunnel junctions 140 in the first magnetic field sensitive region 120 can be magnetically reset accordingly.

[0054] One end of the magnetoresistance unit R11 is connected to the output terminal P1, and the other end of the magnetoresistance unit R11 is connected to the power supply terminal VCC1; one end of the magnetoresistance unit R14 is connected to the output terminal N1, and the other end of the magnetoresistance unit R14 is connected to the power supply terminal VCC1; one end of the magnetoresistance unit R12 is connected to the output terminal P1, and the other end of the magnetoresistance unit R12 is connected to the ground terminal GND; one end of the magnetoresistance unit R13 is connected to the output terminal N1, and the other end of the magnetoresistance unit R13 is connected to the ground terminal GND.

[0055] Specifically, the hollow arrows in FIG4 indicate the pinning direction of the magnetic tunnel junction 140, and the solid arrows indicate the initial magnetization direction of the free layer of the magnetic tunnel junction 140. When preparing the magnetic tunnel junction 140, the magnetic tunnel junctions 140 used to form the magnetoresistive units R11 and R13 are annealed along the positive direction of the X-axis, resulting in a pinning direction along the positive direction of the X-axis; the magnetic tunnel junctions 140 used to form the magnetoresistive units R12 and R14 are annealed along the negative direction of the X-axis, resulting in a pinning direction along the negative direction of the X-axis. As shown in FIG5, when the sensor is operating, the coil current in the region where the magnetoresistive units R11 and R14 are located is directed along the positive direction of the X-axis, generating a set magnetic field along the positive direction of the Y-axis. The coil current in the region where the magnetoresistive units R12 and R13 are located is directed along the negative direction of the X-axis, generating a set magnetic field along the negative direction of the Y-axis. Therefore, the magnetoresistive unit R11 and the magnetoresistive unit R14 have the same initial magnetization direction of the free layer, both in the positive direction of the Y axis, and the magnetoresistive unit R12 and the magnetoresistive unit R13 have the same initial magnetization direction of the free layer, both in the negative direction of the Y axis.

[0056] When the sensor is operating and the external magnetic field has a component along the X-axis, the magnetization direction of the free layer of magnetic tunnel junction 140 rotates at different angles depending on the magnitude of the magnetic field component, causing the resistance of magnetoresistive elements R11 and R13 to increase or decrease. The resistance change of magnetoresistive elements R12 and R14 is opposite to the resistance change of magnetoresistive elements R11 and R13. The differential signal S1 of the X-axis bridge has a nearly linear relationship with the X-axis component of the external magnetic field, as shown in the following equation:

[0057] Among them, MR and H k represents the intrinsic properties of the magnetic tunnel junction 140, namely magnetoresistivity and anisotropy field; V P1 Represents the output signal of output terminal P1, V N1 represents the output signal of the output terminal N1; Hx represents the X-axis component of the external magnetic field.

[0058] In one embodiment, all magnetic tunnel junctions 140 in the second magnetic field sensitive region 130 are arranged on the inclined surface of the inclined structure. All magnetic tunnel junctions 140 in the second magnetic field sensitive region 130 are arranged on the inclined surface of the groove / protrusion of the substrate 110 to detect the magnetic field of the Y axis and the Z axis.

[0059] As shown in Figures 6 to 8, the magnetic tunnel junctions 140 located in the second magnetic field sensitive area 130 have a pinning direction along the inclined surface of the inclined structure, wherein the magnetic tunnel junctions 140 with the pinning direction along the inclined surface of the inclined structure in the positive upward direction are partially connected in series to form a magnetoresistance unit R21 and partially connected in series to form a magnetoresistance unit R23, the magnetic tunnel junctions 140 with the pinning direction along the inclined surface of the inclined structure in the negative downward direction are partially connected in series to form a magnetoresistance unit R22 and partially connected in series to form a magnetoresistance unit R24, the magnetic tunnel junctions 140 with the pinning direction along the inclined surface of the inclined structure in the positive downward direction are partially connected in series to form a magnetoresistance unit R31 and partially connected in series to form a magnetoresistance unit R33, and the magnetic tunnel junctions 140 with the pinning direction along the inclined surface of the inclined structure in the negative upward direction are partially connected in series to form a magnetoresistance unit R32 and partially connected in series to form a magnetoresistance unit R34. The magnetoresistance units R22, R23, R32 and R33 have free layer initial magnetization directions in the positive direction of the X-axis direction, and the magnetoresistance units R21, R24, R31 and R34 have free layer initial magnetization directions in the negative direction of the X-axis direction.

[0060] One end of the magnetoresistance unit R21 is connected to the output terminal P2, and the other end of the magnetoresistance unit R21 is connected to the power supply terminal VCC2. One end of the magnetoresistance unit R24 is connected to the output terminal N2, and the other end of the magnetoresistance unit R24 is connected to the power supply terminal VCC2. One end of the magnetoresistance unit R22 is connected to the output terminal P2, and the other end of the magnetoresistance unit R22 is connected to the ground terminal GND. One end of the magnetoresistance unit R23 is connected to the output terminal N2, and the other end of the magnetoresistance unit R23 is connected to the ground terminal GND. One end of the magnetoresistance unit R31 is connected to the output terminal P3, and the other end of the magnetoresistance unit R31 is connected to the power supply terminal VCC3. One end of the magnetoresistance unit R34 is connected to the output terminal N3, and the other end of the magnetoresistance unit R34 is connected to the power supply terminal VCC3. One end of the magnetoresistance unit R32 is connected to the output terminal P3, and the other end of the magnetoresistance unit R32 is connected to the ground terminal GND. One end of the magnetoresistance unit R33 is connected to the output terminal N3, and the other end of the magnetoresistance unit R33 is connected to the ground terminal GND.

[0061] Specifically, as shown in Figures 6 and 8, taking the inclined structure as an example, in which the groove is set in the substrate 110, along the positive direction of the Y-axis, the magnetic tunnel junction 140 used to constitute the magnetoresistance unit R31 (magnetoresistance unit R33) and the magnetoresistance unit R32 (magnetoresistance unit R34) is set on the downslope surface of the groove, and the magnetic tunnel junction 140 used to constitute the magnetoresistance unit R21 (magnetoresistance unit R23) and the magnetoresistance unit R22 (magnetoresistance unit R24) is set on the upslope surface of the groove, and the downslope surface (slope 2 shown in Figure 8) and the upslope surface (slope 1 shown in Figure 8) of the groove have the same slope. The magnetic tunnel junctions 140 used to form the magnetoresistive unit R31 (magnetoresistive unit R33) and the magnetoresistive unit R21 (magnetoresistive unit R23) are annealed along the positive direction of the Y axis, so that the pinning direction generated by the magnetoresistive unit R31 (magnetoresistive unit R33) includes a positive component in the Y axis and a negative component in the Z axis, and the pinning direction generated by the magnetoresistive unit R21 (magnetoresistive unit R23) includes a positive component in the Y axis and a positive component in the Z axis. The magnetic tunnel junctions 140 used to form the magnetoresistive unit R22 (magnetoresistive unit R24) and the magnetoresistive unit R32 (magnetoresistive unit R34) are annealed along the negative direction of the Y axis, so that the pinning direction generated by the magnetoresistive unit R22 (magnetoresistive unit R24) includes a negative component in the Y axis and a negative component in the Z axis, and the pinning direction generated by the magnetoresistive unit R32 (magnetoresistive unit R34) includes a negative component in the Y axis and a positive component in the Z axis.

[0062] In Figure 7 , the hollow arrows represent the component of the pinning direction of magnetic tunnel junction 140 along the Y-axis, and the solid arrows represent the initial magnetization direction of the free layer of magnetic tunnel junction 140. The pinning directions of magnetoresistive elements R21, R23, R31, and R33 have a positive component along the Y-axis, while the pinning directions of magnetoresistive elements R22, R24, R32, and R34 have a negative component along the Y-axis. Thus, the two bridges have the same induced output for the Y-axis magnetic field.

[0063] Furthermore, in the left bridge of Figure 7, the pinning directions of the magnetoresistance unit R21 / magnetoresistance unit R24 / magnetoresistance unit R22 / magnetoresistance unit R23 have components along +Z / -Z / -Z / +Z, respectively; in the right bridge, the pinning directions of the magnetoresistance unit R31 / magnetoresistance unit R34 / magnetoresistance unit R32 / magnetoresistance unit R33 have components along -Z / +Z / +Z / -Z, respectively. In this way, the induced outputs of the two bridges for the Z-axis magnetic field are the same in magnitude but opposite in direction.

[0064] As shown in Figure 8, when the sensor is operating, the direction of the coil current in the region where magnetoresistive units R21, R24, R31, and R34 are located is along the positive direction of the Y axis, generating a setting magnetic field along the negative direction of the X axis. The direction of the coil current in the region where magnetoresistive units R23, R22, R33, and R32 are located is along the negative direction of the Y axis, generating a setting magnetic field along the positive direction of the X axis. Therefore, magnetoresistive units R21, R24, R31, and R34 have the same initial free layer magnetization direction, all in the negative direction of the X axis, while magnetoresistive units R23, R22, R33, and R32 have the same initial free layer magnetization direction, all in the positive direction of the X axis.

[0065] When the sensor is working, when the external magnetic field has a component along the Y axis and / or the Z axis, the magnetization direction of the free layer of the magnetic tunnel junction 140 produces different rotation angles depending on the magnitude of the magnetic field component. Under the action of the Y axis magnetic field, the resistance of the magnetoresistive unit R21 / magnetoresistive unit R23 and the magnetoresistive unit R31 / magnetoresistive unit R33 increases or decreases, and the resistance of the magnetoresistive unit R22 / magnetoresistive unit R24 and the magnetoresistive unit R32 / magnetoresistive unit R34 changes, respectively. The resistance changes of magnetoresistive units R23 and R31 / R33 are opposite. Under the action of the Z-axis magnetic field, the resistance of magnetoresistive units R21 / R23 and R32 / R34 increases or decreases, and the resistance changes of magnetoresistive units R22 / R24 and R31 / R33 are opposite to the resistance changes of magnetoresistive units R21 / R23 and R32 / R34, respectively. In Figure 7, the differential signal S2 of the left Y / Z-axis bridge and the differential signal S3 of the right Y / Z-axis bridge have an approximately linear relationship with the Y-axis component and Z-axis component of the external magnetic field, as shown in the following equation:

[0066] Among them, MR and H k represents the intrinsic properties of the magnetic tunnel junction 140, namely magnetoresistivity and anisotropy field; V P2 、V P3 Respectively represent the output signals of output terminals P2 and P3, V N2 、V N3 Hy and Hz represent the Y-axis component and the Z-axis component of the external magnetic field, respectively; θ represents the inclination angle of the inclined surface of the inclined structure relative to the plane of the substrate 110.

[0067] As can be seen above, the signal S2+S3 has a linear relationship with the Y-axis magnetic field component, and the signal S2-S3 has a linear relationship with the Z-axis magnetic field component. In other words, the Y-axis magnetic field component can be analyzed based on the sum of the differential signals S2 and S3, and the Z-axis magnetic field component can be analyzed based on the difference between the differential signals S2 and S3.

[0068] In another embodiment, as shown in Figures 9-11, the magnetic tunnel junction 140 in the second magnetic field sensitive region 130 for detecting the second direction magnetic field is arranged on the plane of the substrate 110; the magnetic tunnel junction 140 in the second magnetic field sensitive region 130 for detecting the third direction magnetic field is arranged on the inclined surface of the inclined structure. Specifically, the magnetic tunnel junction 140 in the first magnetic field sensitive region 120 is arranged on the plane of the substrate 110, has a pinning direction along the X-axis, and detects the magnetic field in the X-axis direction. The second magnetic field sensitive region 130 can be divided into a Y-sensitive region and a Z-sensitive region. The magnetic tunnel junction 140 in the Y-sensitive region is arranged on the plane of the substrate 110, has a pinning direction along the Y-axis, and detects the magnetic field in the Y-axis direction. The magnetic tunnel junction 140 in the Z-sensitive region is arranged on the inclined surface of the inclined structure, has a pinning direction along the inclined surface of the inclined structure, and detects the magnetic field in the Z-axis direction.

[0069] In one embodiment, as shown in Figures 12 and 13, in the magnetic tunnel junction 140 located in the second magnetic field sensitive area 130 for detecting the magnetic field in the Y-axis direction, a portion of the magnetic tunnel junction 140 having a pinning direction along the positive direction of the Y-axis direction is connected in series to form a magnetoresistive unit R25, and another portion is connected in series to form a magnetoresistive unit R27; a portion of the magnetic tunnel junction 140 having a pinning direction along the negative direction of the Y-axis direction is connected in series to form a magnetoresistive unit R26, and another portion is connected in series to form a magnetoresistive unit R28; the magnetoresistive unit R25 and the magnetoresistive unit R28 have an initial free layer magnetization direction along the positive direction of the X-axis direction, and the magnetoresistive unit R26 and the magnetoresistive unit R27 have an initial free layer magnetization direction along the negative direction of the X-axis direction. One end of the magnetoresistance unit R25 is connected to the output terminal P4, and the other end of the magnetoresistance unit R25 is connected to the power supply terminal VCC4; one end of the magnetoresistance unit R28 is connected to the output terminal N4, and the other end of the magnetoresistance unit R28 is connected to the power supply terminal VCC4; one end of the magnetoresistance unit R26 is connected to the output terminal P4, and the other end of the magnetoresistance unit R26 is connected to the ground terminal GND; one end of the magnetoresistance unit R27 is connected to the output terminal N4, and the other end of the magnetoresistance unit R27 is connected to the ground terminal GND.

[0070] Specifically, the hollow arrows in FIG12 indicate the pinning direction of the magnetic tunnel junction 140, and the solid arrows indicate the initial magnetization direction of the free layer of the magnetic tunnel junction 140. When preparing the magnetic tunnel junction 140, the magnetic tunnel junction 140 constituting the magnetoresistive units R25 and R27 is subjected to regional annealing along the positive direction of the Y-axis, generating a pinning direction along the positive direction of the Y-axis; the magnetic tunnel junction 140 constituting the magnetoresistive units R26 and R28 is subjected to regional annealing along the negative direction of the Y-axis, generating a pinning direction along the negative direction of the Y-axis. As shown in FIG13, when the sensor is operating, the coil current in the region where the magnetoresistive units R25 and R28 are located is directed along the negative direction of the Y-axis, generating a set magnetic field along the positive direction of the X-axis. The coil current in the region where the magnetoresistive units R27 and R26 are located is directed along the positive direction of the Y-axis, generating a set magnetic field along the negative direction of the X-axis. Therefore, the magnetoresistive unit R25 and the magnetoresistive unit R28 have the same initial magnetization direction of the free layer, both in the positive direction of the X axis, and the magnetoresistive unit R27 and the magnetoresistive unit R26 have the same initial magnetization direction of the free layer, both in the negative direction of the X axis.

[0071] When the sensor is operating and the external magnetic field has a component along the Y-axis, the magnetization direction of the free layer of magnetic tunnel junction 140 rotates at different angles depending on the magnitude of the magnetic field component, causing the resistance of magnetoresistive elements R25 and R27 to increase or decrease. The resistance change of magnetoresistive elements R26 and R28 is opposite to the resistance change of magnetoresistive elements R25 and R27. The differential signal S4 of the Y-axis bridge has a nearly linear relationship with the Y-axis component of the external magnetic field, as shown in the following equation:

[0072] Among them, MR and H k represents the intrinsic properties of the magnetic tunnel junction 140, namely magnetoresistivity and anisotropy field; V P4 Represents the output signal of output terminal P4, V N4 represents the output signal of the output terminal N4; Hy represents the Y-axis component of the external magnetic field.

[0073] In one embodiment, as shown in Figures 14 to 16, in the magnetic tunnel junctions 140 located in the second magnetic field sensitive region 130 for detecting the magnetic field in the Z-axis direction, along the positive direction of the Y-axis, the magnetic tunnel junctions 140 having a pinning direction along the inclined surface of the inclined structure in the positive upward direction are partially connected in series to form a magnetoresistive unit R35 and partially connected in series to form a magnetoresistive unit R37, while the magnetic tunnel junctions 140 having a pinning direction along the inclined surface of the inclined structure in the positive downward direction are partially connected in series to form a magnetoresistive unit R36 and partially connected in series to form a magnetoresistive unit R38. The magnetoresistive units R35 and R38 have initial free layer magnetization directions in the negative direction of the X-axis, while the magnetoresistive units R36 and R37 have initial free layer magnetization directions in the positive direction of the X-axis.

[0074] One end of the magnetoresistance unit R35 is connected to the output terminal P5, and the other end of the magnetoresistance unit R35 is connected to the power supply terminal VCC5. One end of the magnetoresistance unit R38 is connected to the output terminal N5, and the other end of the magnetoresistance unit R38 is connected to the power supply terminal VCC5. One end of the magnetoresistance unit R36 is connected to the output terminal P5, and the other end of the magnetoresistance unit R36 is connected to the ground terminal GND. One end of the magnetoresistance unit R37 is connected to the output terminal N5, and the other end of the magnetoresistance unit R37 is connected to the ground terminal GND.

[0075] Specifically, as shown in FIG14 , taking the example of a groove provided in the substrate 110 as an example, along the positive direction of the Y axis, the magnetic tunnel junction 140 constituting the magnetoresistive unit R36 (magnetoresistive unit R38) is disposed on the downward slope of the groove, while the magnetic tunnel junction 140 constituting the magnetoresistive unit R35 (magnetoresistive unit R37) is disposed on the upward slope of the groove. The downward and upward slopes of the groove have the same slope. The magnetic tunnel junctions 140 constituting the magnetoresistive unit R36 (magnetoresistive unit R38) and the magnetoresistive unit R35 (magnetoresistive unit R37) are annealed along the positive direction of the Y axis, such that the pinning direction generated by the magnetoresistive unit R36 (magnetoresistive unit R38) includes a positive component in the Y axis and a negative component in the Z axis, while the pinning direction generated by the magnetoresistive unit R35 (magnetoresistive unit R37) includes a positive component in the Y axis and a positive component in the Z axis.

[0076] In Figure 15 , the hollow arrows indicate the component of the pinning direction of magnetic tunnel junction 140 along the Y-axis, and the solid arrows indicate the initial magnetization direction of the free layer of magnetic tunnel junction 140. The pinning directions of magnetoresistive elements R35, R36, R37, and R38 all have components along the positive Y-axis. Thus, the induced output of the Z-axis bridge for the Y-axis magnetic field is zero.

[0077] Furthermore, the pinning directions of the magnetoresistive units R36 and R38 include the negative direction component of the Z axis, and the pinning directions of the magnetoresistive units R35 and R37 include the positive direction component of the Z axis, so that the Z-axis bridge has an inductive output for the Z-axis magnetic field.

[0078] As shown in Figure 16, when the sensor is operating, the coil current in the region where magnetoresistive units R35 and R38 are located is directed along the positive direction of the Y axis, generating a setting magnetic field in the negative direction of the X axis. The coil current in the region where magnetoresistive units R36 and R37 are located is directed along the negative direction of the Y axis, generating a setting magnetic field in the positive direction of the X axis. Therefore, magnetoresistive units R35 and R38 have the same initial free layer magnetization direction, both in the negative direction of the X axis, while magnetoresistive units R36 and R37 have the same initial free layer magnetization direction, both in the positive direction of the X axis.

[0079] When the sensor is operating and the external magnetic field has a component along the Z-axis, the magnetization direction of the free layer of magnetic tunnel junction 140 rotates at different angles depending on the magnitude of the magnetic field component, causing the resistance of magnetoresistive units R35 and R37 to increase or decrease. The resistance of magnetoresistive units R36 and R38 changes in a manner opposite to the resistance change of magnetoresistive units R35 and R37. The differential signal S5 of the Z-axis bridge has a nearly linear relationship with the Z-axis component of the external magnetic field, as shown in the following equation:

[0080] Among them, MR and H k represents the intrinsic properties of the magnetic tunnel junction 140, namely magnetoresistivity and anisotropy field; V P5 Represents the output signal of output terminal P5, V N5 represents the output signal of the output terminal N5; Hz represents the Z-axis component of the external magnetic field; and θ represents the tilt angle of the inclined surface of the inclined structure relative to the plane of the substrate 110.

[0081] As can be seen from the above, the components of the pinning directions of the magnetoresistive units in the Z-axis bridge in the Y-axis direction are in the same direction. Therefore, the changes in resistance caused by the Y-axis magnetic field are consistent, resulting in the constructed bridge having no signal output in the Y-axis direction. However, the components of the pinning directions of the magnetoresistive units in the Z-axis direction are both positive and negative. Therefore, the Z-axis magnetic field component can be analyzed based on the differential signal S5.

[0082] In one embodiment, a method for preparing a TMR magnetic sensor is provided, comprising:

[0083] An inclined structure is formed on the substrate, wherein an inclined surface of the inclined structure is inclined between a second direction and a third direction;

[0084] A magnetic tunnel junction is formed on a substrate; the substrate is provided with a first magnetic field sensitive region and a second magnetic field sensitive region, both of which are composed of magnetic tunnel junctions connected in series or in parallel or in a combination of series and parallel connections; the magnetic tunnel junction located in the first magnetic field sensitive region is arranged in the plane of the substrate and has a pinning direction along a first direction; the magnetic tunnel junction located in the second magnetic field sensitive region is at least partially arranged on the inclined surface of the inclined structure, and the magnetic tunnel junction arranged on the inclined surface of the inclined structure has a pinning direction along the inclined surface of the inclined structure; the first direction, the second direction and the third direction are perpendicular to each other, and the third direction is also perpendicular to the plane of the substrate.

[0085] In one embodiment, manufacturing an inclined structure on a substrate includes: providing a substrate; forming a first passivation layer on a surface of the substrate, wherein the substrate and the first passivation layer constitute the substrate; and arranging the inclined structure on the first passivation layer.

[0086] In one embodiment, forming a magnetic tunnel junction on a substrate includes: forming a TMR magnetic multilayer film on a flat surface of the substrate and an inclined surface of an inclined structure; applying a release adhesive on the substrate and etching the TMR magnetic multilayer film to form a first metal layer and a magnetic tunnel junction; and performing metal coating and etching on the substrate to form a second metal layer connecting each magnetic tunnel junction.

[0087] In one embodiment, applying a stripping glue on a substrate and etching the TMR magnetic multilayer film to form a first metal layer and a magnetic tunnel junction includes: applying a stripping glue on the substrate for a first time and etching the TMR magnetic multilayer film located on the plane of the substrate / the inclined surface of the inclined structure to form the first metal layer and the magnetic tunnel junction located on the plane of the substrate / the inclined surface of the inclined structure; applying a stripping glue on the substrate for a second time and etching the TMR magnetic multilayer film located on the inclined surface of the inclined structure / the plane of the substrate to form the first metal layer and the magnetic tunnel junction located on the inclined surface of the inclined structure / the plane of the substrate.

[0088] It should be noted that the specific type of the tilted structure, as well as the arrangement and connection relationship of the magnetic tunnel junctions in the first magnetic field sensitive region and the second magnetic field sensitive region, have been explained in detail in the above-mentioned TMR magnetic sensor and will not be repeated here.

[0089] Specifically, the preparation process of the TMR magnetic sensor is as follows:

[0090] As shown in FIG17 , a substrate 112 is first provided. The substrate 112 includes a CMOS wafer layer 1122 and a CMOS signal layer 1124 covering the CMOS wafer layer 1122. An integrated circuit composed of a plurality of MOS tubes is integrated in the CMOS wafer layer 1122, which can process the analog signals generated by the first magnetic field sensitive area and the second magnetic field sensitive area inducing the external magnetic field to obtain digital signals. The CMOS signal layer 1124 can realize functions such as receiving analog signals and outputting digital signals. The CMOS signal layer 1124 can be in the form of a metal layer, an integrated circuit layer, etc. Furthermore, the substrate 112 may also include a protective layer 1126 arranged on the CMOS signal layer 1124, which is used to protect the CMOS signal layer 1124. The material of the protective layer 1126 can specifically be silicon oxide (SiO2) or aluminum oxide (AlO x )wait.

[0091] As shown in FIG18 , a first passivation layer 114 is formed on the surface of the substrate 112. The substrate 112 and the first passivation layer 114 constitute the substrate 110. The first passivation layer 114 may be a silicon dioxide layer having a thickness of 3 μm to 5 μm. The first passivation layer 114 may be formed on the substrate 112 by coating, physical vapor deposition (PVD), chemical vapor deposition (CVD), or the like. As shown in FIG19 , the first passivation layer 114 is etched to form a groove, and the etching stops at the CMOS signal layer 1124. As shown in FIG20 , a thin film is re-deposited on the substrate 110 to cover the CMOS signal layer 1124 exposed in the groove. The material of the thin film may be one or both of silicon oxide and silicon nitride.

[0092] As shown in FIG21 , a TMR magnetic multilayer film 140a is deposited on a substrate 110. The TMR magnetic multilayer film 140a covers both the flat surface and the grooved portions of the substrate 110. The TMR magnetic multilayer film 140a comprises a multilayer structure, specifically including structures for the subsequent formation of a magnetic tunnel junction and a first metal layer. As shown in FIG22 , the TMR magnetic multilayer film 140a is etched down to the underlying metal conductors, leaving portions for the subsequent formation of the first metal layer and the magnetic tunnel junction 140. Furthermore, the TMR magnetic multilayer film 140a in at least one of the grooves is etched away to serve as a connection trench. As shown in FIG23 , a connection hole 140b is etched along the thickness of the bottom of the connection trench in the substrate 110 to expose the CMOS signal layer 1124 for subsequent connection of the second metal layer to the CMOS signal layer 1124.

[0093] As shown in FIG24 , a release adhesive 160 is applied to the substrate 110 and photolithography is performed. The portion of the release adhesive 160 covering the connection hole 140b and the portion of the release adhesive 160 on the TMR magnetic multilayer film 140a used to form the magnetic tunnel junction and support the second metal layer are retained. As shown in FIG25 , the TMR magnetic multilayer film 140a is patterned and the portion of the TMR magnetic multilayer film 140a not covered by the release adhesive 160 is etched to form a first metal layer 170 and the magnetic tunnel junctions 140. The first metal layer 170 is used to connect the magnetic tunnel junctions 140. As shown in FIG26 , a portion of a second passivation layer 180 is deposited on the substrate 110 and the release adhesive 160 is removed. The deposited portion of the second passivation layer 180 exposes the magnetic tunnel junctions 140, the connection hole 140b, and the portion of the TMR magnetic multilayer film 140a used to support the second metal layer. The second passivation layer 180 can be made of aluminum oxide or silicon oxide.

[0094] As shown in FIG27 , metal plating and etching are performed on the substrate 110 to form a second metal layer 190. The second metal layer 190 connects the magnetic tunnel junctions 140 and extends to the substrate 110 through the connection holes 140b, electrically connecting the magnetic tunnel junctions 140 and the substrate 110, thereby receiving the output signal of the bridge formed by the magnetic tunnel junctions 140. As shown in FIG28 , another portion of the second passivation layer 180 is deposited on the second metal layer 190, covering the second metal layer 190, thereby forming a complete second passivation layer 180. As shown in FIG29 and FIG30 , the second passivation layer 180 is etched to form a top connection hole 180a that exposes the second metal layer 190. Metal deposition and etching are then performed to form a top metal layer 200. A portion of the top metal layer 200 is used to form the coil 150, and a portion is used to connect to the second metal layer 190 through the top connection hole 180a. Finally, as shown in FIG31 , a third passivation layer 210 is deposited on the top metal layer 200 and conductive solder joint openings 210 a are formed. This protects the top metal layer 200 while also electrically connecting the portion of the top metal layer 200 used to connect to the second metal layer 190 to an external device through the conductive solder joint openings 210 a. The third passivation layer 210 can also be made of aluminum oxide or silicon oxide.

[0095] It should be noted that the above-described TMR magnetic sensor fabrication process employs a method of applying a single stripping adhesive, followed by simultaneous patterning and etching of the TMR magnetic multilayer film 140a located on the flat surface of the substrate 110 and the inclined surface of the inclined structure, thereby forming magnetic tunnel junctions 140 on the flat surface and the inclined surface of the inclined structure, respectively. In other embodiments, the stripping adhesive may be applied twice, and the TMR magnetic multilayer film 140a located on the flat surface of the substrate 110 and the inclined surface of the inclined structure may be patterned and etched, respectively, to form magnetic tunnel junctions 140 at corresponding locations. For example, the stripping adhesive may be applied once, and the TMR magnetic multilayer film 140a located on the flat surface of the substrate 110 / the inclined surface of the inclined structure may be patterned and etched, thereby forming magnetic tunnel junctions 140 located on the flat surface of the substrate 110 / the inclined surface of the inclined structure. Subsequently, the stripping adhesive may be applied a second time, and the TMR magnetic multilayer film 140a located on the inclined surface of the inclined structure / the flat surface of the substrate 110 may be patterned and etched, thereby forming magnetic tunnel junctions 140 located on the inclined surface of the inclined structure / the flat surface of the substrate 110.

[0096] Specifically, after the preparation process shown in Figures 17 to 23, a connection hole 140b is etched along the thickness direction at the bottom of the connection groove of substrate 110. As shown in Figure 32, a first coating of stripping adhesive 160a is performed on substrate 110. The stripping adhesive 160a located on the plane of substrate 110 is exposed and developed, thereby covering the portion of the TMR magnetic multilayer film 140a located on the plane of substrate 110 that is used to form the magnetic tunnel junction, while exposing the surrounding portion. As shown in Figure 33, the exposed portion of the TMR magnetic multilayer film 140a located on the plane of substrate 110 is ion beam etched to form the first metal layer 170 and the magnetic tunnel junction 140 on the plane of substrate 110, while retaining the stripping adhesive 160a. As shown in Figure 34, a second passivation layer 180 is deposited on the portion of substrate 110 located on the plane of substrate 110. The stripping adhesive 160a is then removed. The deposited portion of the second passivation layer 180 in this step covers the first metal layer 170 on the plane of substrate 110, exposing the magnetic tunnel junction 140 on the plane of substrate 110. The second passivation layer 180 may be made of aluminum oxide or silicon oxide.

[0097] As shown in FIG35 , a second coating of stripping adhesive 160b is applied to substrate 110. The stripping adhesive 160b located in the groove of substrate 110 is exposed and developed, thereby masking the portion of the TMR magnetic multilayer film 140a located in the groove of substrate 110 that is used to form the magnetic tunnel junction, while leaving the surrounding portion exposed. As shown in FIG36 , the exposed portion of the TMR magnetic multilayer film 140a located in the groove of substrate 110 is ion beam etched to form the first metal layer 170 and the magnetic tunnel junction 140 in the groove, while retaining the stripping adhesive 160b. The first metal layer 170 is used to connect the magnetic tunnel junctions 140. As shown in FIG37 , a second passivation layer 180 is deposited on substrate 110 in a portion of the groove. The stripping adhesive 160b is then removed. The portion of second passivation layer 180 deposited in this step is connected to the portion of second passivation layer 180 located on the flat surface of substrate 110. The portion of second passivation layer 180 deposited in this step also covers the first metal layer 170 in the groove, exposing the magnetic tunnel junction 140 in the groove. The second passivation layer 180 is not deposited on the connection groove where the connection hole 140 b is provided and the portion of the TMR magnetic multilayer film 140 a for supporting the second metal layer.

[0098] As shown in FIG38 , metal plating and etching are performed on substrate 110 to form a second metal layer 190. Second metal layer 190 connects each magnetic tunnel junction 140 and extends to substrate 110 through connection holes 140b, electrically connecting the magnetic tunnel junctions 140 and substrate 110 to receive the output signal of the bridge formed by the magnetic tunnel junctions 140. As shown in FIG39 , the remaining portion of second passivation layer 180 is deposited on second metal layer 190, covering second metal layer 190 to form a complete second passivation layer 180. As shown in FIG40 and FIG41 , second passivation layer 180 is etched to form top connection holes 180a that expose second metal layer 190. Metal deposition and etching are then performed to form top metal layer 200. A portion of top metal layer 200 is used to form coil 150, and a portion is used to connect to second metal layer 190 through top connection holes 180a. Finally, as shown in Figures 42 and 43, a third passivation layer 210 is deposited on the top metal layer 200 and conductive solder joint openings 210a are formed. This protects the top metal layer 200 while also electrically connecting the portion of the top metal layer 200 that is used to connect to the second metal layer 190 to an external device through the conductive solder joint openings 210a. The third passivation layer 210 can also be aluminum oxide or silicon oxide.

[0099] Due to the fluidity of the stripping adhesive, it can easily form an uneven thickness distribution on the inclined surface of the inclined structure, making it difficult to simultaneously form an ideal stripping adhesive morphology on both the flat surface of the substrate 110 and the inclined surface of the inclined structure, thereby preventing the formation of an ideal magnetic tunnel junction structure. By applying the stripping adhesive twice for pattern etching, namely applying the stripping adhesive separately on the flat surface and the inclined surface, the stripping adhesive forms relatively good morphologies on both the flat surface and the inclined surface, and then forming the magnetic tunnel junctions on the flat surface and the inclined surface separately, the photolithography processes for the magnetic tunnel junction structures on the flat surface and the inclined surface are separated, ensuring the desired structural pattern and improving fabrication reliability.

[0100] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0101] The above embodiments merely illustrate several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A TMR magnetic sensor, characterized in that: include: a substrate, the substrate comprising an inclined structure, wherein an inclined surface of the inclined structure is inclined between a second direction and a third direction; A first magnetic field sensitive region and a second magnetic field sensitive region are provided on the substrate, wherein the first magnetic field sensitive region and the second magnetic field sensitive region are both composed of magnetic tunnel junctions connected in series or in parallel or in a combination of series and parallel connections; the magnetic tunnel junction located in the first magnetic field sensitive region is arranged in the plane of the substrate and has a pinning direction along a first direction; the magnetic tunnel junction located in the second magnetic field sensitive region is at least partially arranged on the inclined surface of the inclined structure, and the magnetic tunnel junction arranged on the inclined surface of the inclined structure has a pinning direction along the inclined surface of the inclined structure; The first direction, the second direction and the third direction are perpendicular to each other, and the third direction is also perpendicular to the plane of the substrate.

2. The TMR magnetic sensor according to claim 1, wherein The device further comprises a coil disposed on the substrate, wherein the coil is used to reset the magnetic tunnel junctions in the first magnetic field sensitive region and the second magnetic field sensitive region when powered on.

3. The TMR magnetic sensor according to claim 2, wherein: The coil is a multi-turn planar coil; the portion of the coil that transmits current along the first direction is arranged corresponding to the first magnetic field sensitive area; the portion of the coil that transmits current along the second direction is arranged corresponding to the second magnetic field sensitive area; the number of first magnetic field sensitive areas is two, and they are distributed along the second direction; the number of second magnetic field sensitive areas is two, and they are distributed along the first direction, and are respectively located on both sides of the axis where the two first magnetic field sensitive areas are located.

4. The TMR magnetic sensor according to any one of claims 1 to 3, characterized in that: Among the magnetic tunnel junctions located in the first magnetic field sensitive region, a portion of the magnetic tunnel junctions having a pinning direction along the positive direction of the first direction are connected in series to form a magnetoresistive unit R11, and another portion are connected in series to form a magnetoresistive unit R13; a portion of the magnetic tunnel junctions having a pinning direction along the negative direction of the first direction are connected in series to form a magnetoresistive unit R12, and another portion are connected in series to form a magnetoresistive unit R14; the magnetoresistive units R11 and R14 have initial free layer magnetization directions along the positive direction of the second direction, and the magnetoresistive units R12 and R13 have initial free layer magnetization directions along the negative direction of the second direction; One end of the magnetoresistance unit R11 is connected to the output terminal P1, and the other end of the magnetoresistance unit R11 is connected to the power supply terminal VCC1; one end of the magnetoresistance unit R14 is connected to the output terminal N1, and the other end of the magnetoresistance unit R14 is connected to the power supply terminal VCC1; one end of the magnetoresistance unit R12 is connected to the output terminal P1, and the other end of the magnetoresistance unit R12 is connected to the ground terminal; one end of the magnetoresistance unit R13 is connected to the output terminal N1, and the other end of the magnetoresistance unit R13 is connected to the ground terminal.

5. The TMR magnetic sensor according to any one of claims 1 to 3, characterized in that: All magnetic tunnel junctions in the second magnetic field sensitive region are arranged on the inclined surface of the inclined structure.

6. The TMR magnetic sensor according to claim 5, wherein: The magnetic tunnel junctions located in the second magnetic field sensitive region have a pinning direction along the inclined surface of the inclined structure, wherein the magnetic tunnel junctions having the pinning direction along the inclined surface of the inclined structure in a positive upward direction are partially connected in series to form a magnetoresistive unit R21 and partially connected in series to form a magnetoresistive unit R23, the magnetic tunnel junctions having the pinning direction along the inclined surface of the inclined structure in a negative downward direction are partially connected in series to form a magnetoresistive unit R22 and partially connected in series to form a magnetoresistive unit R24, the magnetic tunnel junctions having the pinning direction along the inclined surface of the inclined structure in a positive downward direction are partially connected in series to form a magnetoresistive unit R31 and partially connected in series to form a magnetoresistive unit R33, and the magnetic tunnel junctions having the pinning direction along the inclined surface of the inclined structure in a negative upward direction are partially connected in series to form a magnetoresistive unit R32 and partially connected in series to form a magnetoresistive unit R34; The magnetoresistive units R22, R23, R32, and R33 have free layer initial magnetization directions along the positive direction of the first direction, and the magnetoresistive units R21, R24, R31, and R34 have free layer initial magnetization directions along the negative direction of the first direction; One end of the magnetoresistance unit R21 is connected to the output terminal P2, and the other end of the magnetoresistance unit R21 is connected to the power supply terminal VCC2; one end of the magnetoresistance unit R24 is connected to the output terminal N2, and the other end of the magnetoresistance unit R24 is connected to the power supply terminal VCC2; one end of the magnetoresistance unit R22 is connected to the output terminal P2, and the other end of the magnetoresistance unit R22 is connected to the ground terminal; one end of the magnetoresistance unit R23 is connected to the output terminal N2, and the other end of the magnetoresistance unit R23 is connected to the ground terminal; One end of the magnetoresistance unit R31 is connected to the output terminal P3, and the other end of the magnetoresistance unit R31 is connected to the power supply terminal VCC3; one end of the magnetoresistance unit R34 is connected to the output terminal N3, and the other end of the magnetoresistance unit R34 is connected to the power supply terminal VCC3; one end of the magnetoresistance unit R32 is connected to the output terminal P3, and the other end of the magnetoresistance unit R32 is connected to the ground terminal; one end of the magnetoresistance unit R33 is connected to the output terminal N3, and the other end of the magnetoresistance unit R33 is connected to the ground terminal.

7. The TMR magnetic sensor according to any one of claims 1 to 3, characterized in that: The magnetic tunnel junction in the second magnetic field sensitive area for detecting the second direction magnetic field is arranged on the plane of the substrate; the magnetic tunnel junction in the second magnetic field sensitive area for detecting the third direction magnetic field is arranged on the inclined surface of the inclined structure.

8. The TMR magnetic sensor according to claim 7, wherein: In the magnetic tunnel junction located in the second magnetic field sensitive region for detecting a magnetic field in a second direction, a portion of the magnetic tunnel junctions having a pinning direction along the positive direction of the second direction are connected in series to form a magnetoresistive unit R25, and another portion are connected in series to form a magnetoresistive unit R27; a portion of the magnetic tunnel junctions having a pinning direction along the negative direction of the second direction are connected in series to form a magnetoresistive unit R26, and another portion are connected in series to form a magnetoresistive unit R28; the magnetoresistive units R25 and R28 have initial free layer magnetization directions along the positive direction of the first direction, and the magnetoresistive units R26 and R27 have initial free layer magnetization directions along the negative direction of the first direction; One end of the magnetoresistance unit R25 is connected to the output terminal P4, and the other end of the magnetoresistance unit R25 is connected to the power supply terminal VCC4; one end of the magnetoresistance unit R28 is connected to the output terminal N4, and the other end of the magnetoresistance unit R28 is connected to the power supply terminal VCC4; one end of the magnetoresistance unit R26 is connected to the output terminal P4, and the other end of the magnetoresistance unit R26 is connected to the ground terminal; one end of the magnetoresistance unit R27 is connected to the output terminal N4, and the other end of the magnetoresistance unit R27 is connected to the ground terminal.

9. The TMR magnetic sensor according to claim 7, wherein: In the magnetic tunnel junction located in the second magnetic field sensitive region for detecting the third directional magnetic field, the magnetic tunnel junctions having a pinning direction along the inclined surface of the inclined structure in a positive upward direction are partially connected in series to form a magnetoresistive unit R35 and partially connected in series to form a magnetoresistive unit R37, and the magnetic tunnel junctions having a pinning direction along the inclined surface of the inclined structure in a positive downward direction are partially connected in series to form a magnetoresistive unit R36 and partially connected in series to form a magnetoresistive unit R38; the magnetoresistive unit R35 and the magnetoresistive unit R38 have initial free layer magnetization directions along the negative direction of the first direction, and the magnetoresistive unit R36 and the magnetoresistive unit R37 have initial free layer magnetization directions along the positive direction of the first direction; One end of the magnetic resistance unit R35 is connected to the output terminal P5, and the other end of the magnetic resistance unit R35 is connected to the power supply terminal VCC5; one end of the magnetic resistance unit R38 is connected to the output terminal N5, and the other end of the magnetic resistance unit R38 is connected to the power supply terminal VCC5; One end of the magnetoresistance unit R36 is connected to the output terminal P5, and the other end of the magnetoresistance unit R36 is connected to the ground terminal. One end of the magnetoresistance unit R37 is connected to the output terminal N5, and the other end of the magnetoresistance unit R37 is connected to the ground terminal.

10. The TMR magnetic sensor according to any one of claims 1 to 3, characterized in that: The substrate further includes a base and a first passivation layer disposed on the base; the inclined structure is disposed on the first passivation layer.

11. The TMR magnetic sensor according to claim 10, wherein: The substrate comprises a CMOS wafer layer, a CMOS signal layer and a protection layer which are stacked in sequence.

12. The TMR magnetic sensor according to claim 10, wherein: Also included is a second passivation layer encapsulating the magnetic tunnel junction.

13. The TMR magnetic sensor according to any one of claims 1 to 3, characterized in that: The inclined structure is a groove or a protrusion.

14. The TMR magnetic sensor according to any one of claims 1 to 3, characterized in that: A magnetic tunnel junction array layout located in the first magnetic field sensitive region, and / or a magnetic tunnel junction array layout located in the second magnetic field sensitive region.

15. The TMR magnetic sensor according to any one of claims 1 to 3, characterized in that: A first metal layer is provided on the side of the magnetic tunnel junction close to the substrate, and a second metal layer is provided on the side of the magnetic tunnel junction away from the substrate. The first metal layer and the second metal layer are used to connect the magnetic tunnel junctions in series to form a magnetoresistive unit, to be used for series / parallel connection between the magnetoresistive units, to connect the magnetoresistive units to a power supply end or a ground setting, and to transmit the output signal of the bridge composed of the magnetoresistive units to the substrate.

16. A method for preparing a TMR magnetic sensor, characterized in that: include: forming an inclined structure on the substrate, wherein an inclined surface of the inclined structure is inclined between a second direction and a third direction; A magnetic tunnel junction is formed on the substrate; the substrate is provided with a first magnetic field sensitive region and a second magnetic field sensitive region, and the first magnetic field sensitive region and the second magnetic field sensitive region are both composed of the magnetic tunnel junctions connected in series, in parallel, or in a combination of series and parallel; the magnetic tunnel junction located in the first magnetic field sensitive region is arranged in the plane of the substrate and has a pinning direction along a first direction; the magnetic tunnel junction located in the second magnetic field sensitive region is at least partially arranged on the inclined surface of the inclined structure, and the magnetic tunnel junction arranged on the inclined surface of the inclined structure has a pinning direction along the inclined surface of the inclined structure; The first direction, the second direction and the third direction are perpendicular to each other, and the third direction is also perpendicular to the plane of the substrate.

17. The method for preparing a TMR magnetic sensor according to claim 16, wherein: The manufacturing of the inclined structure on the substrate comprises: providing a substrate; forming a first passivation layer on the surface of the substrate, wherein the substrate and the first passivation layer constitute the base plate; The inclined structure is provided on the first passivation layer.

18. The method for preparing a TMR magnetic sensor according to claim 16, wherein: The forming of a magnetic tunnel junction on the substrate comprises: forming a TMR magnetic multilayer film on the flat surface of the substrate and the inclined surface of the inclined structure; Applying a release agent on the substrate and etching the TMR magnetic multilayer film to form a first metal layer and the magnetic tunnel junction; Metal coating and etching are performed on the substrate to form a second metal layer connecting the magnetic tunnel junctions.

19. The method for preparing a TMR magnetic sensor according to claim 18, wherein: The step of applying a release adhesive to the substrate and etching the TMR magnetic multilayer film to form a first metal layer and a magnetic tunnel junction comprises: Applying a stripping adhesive to the substrate for the first time, and etching the TMR magnetic multilayer film located on the inclined surface of the planar / inclined structure of the substrate to form the first metal layer and the magnetic tunnel junction located on the inclined surface of the planar / inclined structure of the substrate; A second stripping adhesive is applied to the substrate, and the TMR magnetic multilayer film located on the inclined surface of the inclined structure / the plane of the substrate is etched to form the first metal layer and the magnetic tunnel junction located on the inclined surface of the inclined structure / the plane of the substrate.

20. The method for preparing a TMR magnetic sensor according to claim 18, wherein: The step of applying a release adhesive to the substrate and etching the TMR magnetic multilayer film to form a first metal layer and a magnetic tunnel junction comprises: A stripping adhesive is applied to the substrate, and the TMR magnetic multilayer film located on the plane of the substrate and the inclined surface of the inclined structure is pattern-etched to form magnetic tunnel junctions on the plane of the substrate and the inclined surface of the inclined structure respectively.

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