A three-axis magnetic sensor and its preparation process

Abstract

The present invention discloses a three-axis magnetic sensor and its fabrication process. The three-axis magnetic sensor comprises a substrate formed with at least two grooves, a first magnetic sensing mechanism, a second magnetic sensing mechanism, and a third magnetic sensing mechanism. The first magnetic sensing mechanism is configured to sense a magnetic field in a first direction; the second magnetic sensing mechanism is configured to sense a magnetic field in a second direction; and the third magnetic sensing mechanism is configured to sense a magnetic field in a third direction. The first and second magnetic sensing mechanisms are disposed on the surface of the substrate, while the third magnetic sensing mechanism is disposed within the grooves. At least one pair of adjacent grooves is separated by at least one first magnetic sensing mechanism and / or at least one second magnetic sensing mechanism. The present invention can reduce process errors, increase the process window, and improve the overall product yield.

Description

Technical Field

[0001] The present invention belongs to the field of microelectronics technology and relates to a magnetic sensor, in particular to a three-axis magnetic sensor and a preparation process thereof. Background Art

[0002] Although traditional three-axis magnetic sensors all use a discrete X, Y, and Z bridge resistor design, with the X-axis and Y-axis sensing units in a plane and the Z-axis sensing unit on a slope, the concentrated distribution of the slope brings great difficulties to process control.

[0003] In view of this, there is an urgent need to design a new three-axis magnetic sensor to overcome at least some of the above-mentioned defects of the existing three-axis magnetic sensors. Summary of the Invention

[0004] The present invention provides a three-axis magnetic sensor and a preparation process thereof, which can reduce process processing errors, increase the process window, and improve the overall yield of the product.

[0005] In order to solve the above technical problems, according to one aspect of the present invention, the following technical solution is adopted:

[0006] A three-axis magnetic sensor, comprising:

[0007] a substrate, wherein a surface portion of the substrate is recessed to form at least two grooves;

[0008] At least one first magnetic sensing mechanism, configured to sense a magnetic field in a first direction;

[0009] at least one second magnetic sensing mechanism for sensing a magnetic field in a second direction; and

[0010] at least two third magnetic sensing mechanisms for sensing a magnetic field in a third direction;

[0011] The first direction and the second direction can form a plane, and the plane corresponds to the surface of the substrate, and the third direction intersects with the surface of the substrate; each of the grooves is arranged along the first direction, or is arranged along the second direction, or is partially arranged along the first direction and partially arranged along the second direction; the first magnetic sensing mechanism and the second magnetic sensing mechanism are both arranged on the surface of the substrate, the third magnetic sensing mechanism is arranged in the groove, and each of the third magnetic sensing mechanisms corresponds to each of the grooves one by one; at least one pair of adjacent grooves arranged along the first direction are separated by at least one first magnetic sensing mechanism, and / or at least one pair of adjacent grooves arranged along the second direction are separated by at least one second magnetic sensing mechanism.

[0012] As an embodiment of the present invention, the first magnetic sensing mechanism includes at least one first magnetic resistance strip, and each first magnetic resistance strip extends along the second direction; the second magnetic sensing mechanism includes at least one second magnetic resistance strip, and each second magnetic resistance strip extends along the first direction; the third magnetic sensing mechanism includes at least one third magnetic resistance strip, and each third magnetic resistance strip is arranged on the side wall of the corresponding groove; each of the third magnetic resistance strips extends along the first direction, or extends along the second direction, or partially extends along the first direction and partially extends along the second direction.

[0013] As an embodiment of the present invention, a pseudo magnetoresistive strip not connected to a Wheatstone bridge is provided between the adjacent first magnetoresistive strip and the third magnetoresistive strip, and / or a pseudo magnetoresistive strip not connected to a Wheatstone bridge is provided between the adjacent second magnetoresistive strip and the third magnetoresistive strip.

[0014] As an embodiment of the present invention, a set / reset coil is arranged above and / or below each of the magnetic resistance strips to generate a magnetic field along the easy magnetization axis; and a working electrode is distributed on the upper surface and / or lower surface of the magnetic resistance strip at a set angle to the magnetic resistance strip.

[0015] As an embodiment of the present invention, the direction of the current on the magnetoresistive strip forms an angle of 45° with the easy magnetization axis of the magnetoresistive strip.

[0016] As an embodiment of the present invention, each of the magnetic sensing mechanisms is combined to form an independent Wheatstone bridge, and each bridge arm of each Wheatstone bridge is composed of at least one magnetoresistive strip;

[0017] Several magnetoresistive strips with the same inductive change in response to external magnetic field form the arms of a Wheatstone bridge. A Wheatstone bridge includes two groups of arms whose resistance increases with the input of external magnetic field and two groups of arms whose resistance decreases with the input of external magnetic field.

[0018] As an embodiment of the present invention, a self-detection coil is placed in a local area according to the detection magnetic field of the magnetoresistive strip, and the self-detection coil is used to generate a magnetic field corresponding to the detection direction of the magnetoresistive strip.

[0019] According to another aspect of the present invention, the following technical solution is adopted: a preparation process of a three-axis magnetic sensor, the preparation process comprising:

[0020] Providing a silicon base or a substrate having a circuit;

[0021] At least two grooves are formed on the surface of the substrate; sidewalls of the grooves form a set angle with the substrate surface; the grooves are all arranged along the first direction, or are all arranged along the second direction, or are partially arranged along the first direction and partially arranged along the second direction; at least one pair of adjacent grooves arranged along the first direction has an installation space between them, and / or at least one pair of adjacent grooves arranged along the second direction has an installation space between them; the first direction and the second direction can form a plane, and the plane corresponds to the surface of the substrate;

[0022] forming an insulating layer on the surface of the substrate and the trench;

[0023] A first magnetic sensing mechanism and a second magnetic sensing mechanism are formed on the surface of the insulating layer of the substrate; a third magnetic sensing mechanism is formed on the surface of the insulating layer of the groove; at least one first magnetic sensing mechanism is arranged in an installation space along the first direction and / or at least one second magnetic sensing mechanism is arranged in an installation space along the second direction; the first magnetic sensing mechanism, the second magnetic sensing mechanism and the third magnetic sensing mechanism all contain magnetic materials.

[0024] As an embodiment of the present invention, the preparation process further comprises:

[0025] forming a dielectric layer on the surface of the magnetic material of the first magnetic sensing mechanism, the second magnetic sensing mechanism, and the third magnetic sensing mechanism;

[0026] forming a through hole in the dielectric layer on the surface of the magnetic material;

[0027] forming a continuous electrode layer on the substrate surface and the trench sidewalls;

[0028] The electrode layer is patterned to form a working electrode on the surface of the magnetic material; a through hole formed in the dielectric layer on the surface of the magnetic material enables the magnetic material to contact the subsequently formed working electrode.

[0029] As an embodiment of the present invention, the magnetic material is selected from any one of anisotropic magnetoresistance material, giant magnetoresistance material and tunnel magnetoresistance material; when forming the magnetic material, a magnetic field is simultaneously applied to the substrate for annealing to induce the magnetization direction of the magnetic material and improve the magnetic properties of the magnetic material.

[0030] As an embodiment of the present invention, the preparation process further comprises:

[0031] Lead ends are respectively provided on the substrate surface and at both ends of the magnetoresistive strip in the groove;

[0032] A self-detection coil is provided at the bottom of the groove, below the substrate and below the magnetic sensing mechanism;

[0033] A set coil and / or a reset coil are arranged on the top of the groove, above the substrate and above the magnetic sensing mechanism.

[0034] The beneficial effects of the present invention are as follows: the three-axis magnetic sensor and the preparation process thereof proposed in the present invention can reduce process processing errors, increase the process window, and improve the overall yield of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A partial cross-sectional view of an existing three-axis magnetic sensor.

[0036] Figure 2 FIG. 4 is a partial cross-sectional view of a three-axis magnetic sensor according to an embodiment of the present invention.

[0037] Figure 3 FIG. 4 is a plan view of a three-axis magnetic sensor according to an embodiment of the present invention.

[0038] Figure 4 FIG. 4 is a plan view of a three-axis magnetic sensor according to another embodiment of the present invention.

[0039] Figure 5 FIG. 4 is a plan view of a three-axis magnetic sensor according to another embodiment of the present invention.

[0040] Figure 6 FIG. 1 is a connection diagram of a Wheatstone bridge formed by an X-axis magnetic sensing mechanism in one embodiment of the present invention.

[0041] Figure 7 FIG. 1 is a connection diagram of a Y-axis magnetic sensing mechanism forming a Wheatstone bridge in one embodiment of the present invention.

[0042] Figure 8 FIG. 1 is a schematic diagram illustrating a connection of a Z-axis magnetic sensing mechanism forming a Wheatstone bridge in one embodiment of the present invention.

[0043] Figure 9 FIG. 2 is another connection diagram of a Wheatstone bridge formed by a Z-axis magnetic sensing mechanism in one embodiment of the present invention. DETAILED DESCRIPTION

[0044] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0045] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0046] The description in this section is only for several typical embodiments, and the present invention is not limited to the scope of the embodiments described. The same or similar existing technical means and some technical features of the embodiments are mutually replaced within the scope of the description and protection of the present invention.

[0047] The description of the steps in each embodiment in the specification is for convenience of explanation only. The implementation of this application is not limited by the order in which the steps are implemented. "Connection" in the specification includes both direct connection and indirect connection. In the specification, multiple refers to two or more.

[0048] The present invention discloses a three-axis magnetic sensor, Figure 2 This is a partial cross-sectional diagram of a three-axis magnetic sensor in one embodiment of the present invention, comprising: a substrate, at least one first magnetic sensing mechanism, at least one second magnetic sensing mechanism, and at least two third magnetic sensing mechanisms.

[0049] Each first magnetic sensing mechanism is used to sense a magnetic field in a first direction, each second magnetic sensing mechanism is used to sense a magnetic field in a second direction, and each third magnetic sensing mechanism is used to sense a magnetic field in a third direction.

[0050] The first direction and the second direction can form a plane, and the plane corresponds to the surface of the substrate. The third direction intersects with the surface of the substrate.

[0051] The surface of the substrate is partially recessed to form at least two grooves 4. Each groove 4 is arranged along the first direction, or along the second direction, or partially along the first direction and partially along the second direction.

[0052] The first magnetic sensing mechanism and the second magnetic sensing mechanism are both arranged on the surface of the substrate, and the third magnetic sensing mechanism is arranged in the groove 4, and each third magnetic sensing mechanism corresponds to each groove 4 one by one (that is, one third magnetic sensing mechanism is arranged in one groove 4).

[0053] Among them, at least one pair of adjacent grooves 4 arranged along the first direction are separated by at least one first magnetic sensing mechanism, and / or at least one pair of adjacent grooves 4 arranged along the second direction are separated by at least one second magnetic sensing mechanism.

[0054] For example, if there are three grooves 4 arranged along the first direction, two pairs of adjacent grooves 4 are formed. At least one first magnetic sensing mechanism can be set between the first pair of adjacent grooves 4 to separate the first pair of adjacent grooves 4; and / or, at least one first magnetic sensing mechanism can be set between the second pair of adjacent grooves 4 to separate the second pair of adjacent grooves 4.

[0055] For another example, if there are three grooves 4 arranged along the second direction, two pairs of adjacent grooves 4 are formed. At least one second magnetic sensing mechanism can be set between the first pair of adjacent grooves 4 to separate the first pair of adjacent grooves 4; and / or, at least one second magnetic sensing mechanism can be set between the second pair of adjacent grooves 4 to separate the second pair of adjacent grooves 4.

[0056] At least one pair of adjacent grooves 4 is separated by at least one first magnetic sensing mechanism and / or at least one second magnetic sensing mechanism, so that at least one pair of grooves 4 does not need to be concentrated but opened continuously, thereby reducing the difficulty of process control.

[0057] In one embodiment, for the grooves 4 arranged along the first direction, at least one first magnetic sensing mechanism is provided between each pair of adjacent grooves 4 to separate the adjacent grooves 4; for the grooves 4 arranged along the second direction, at least one second magnetic sensing mechanism is provided between each pair of adjacent grooves 4 to separate the adjacent grooves 4.

[0058] In one embodiment, for the grooves 4 arranged along the first direction, a first magnetic sensing mechanism is provided between each pair of adjacent grooves 4 to separate the adjacent grooves 4; for the grooves 4 arranged along the second direction, a second magnetic sensing mechanism is provided between each pair of adjacent grooves 4 to separate the adjacent grooves 4.

[0059] The first magnetic sensing mechanism includes at least one first magnetoresistive strip, each of which extends along the second direction. That is, the axial direction of the first magnetoresistive strip is aligned with the second direction. When the first magnetic sensing mechanism includes at least two first magnetoresistive strips, each of the first magnetoresistive strips is arranged along the first direction. In one embodiment, the first magnetic sensing mechanism includes two first magnetoresistive strips.

[0060] The second magnetic sensing mechanism includes at least one second magnetoresistive strip, each of which extends along the first direction, i.e., the axial direction of the second magnetoresistive strip is aligned with the first direction. When the second magnetic sensing mechanism includes at least two second magnetoresistive strips, each of the second magnetoresistive strips is arranged along the second direction. In one embodiment, the second magnetic sensing mechanism includes two second magnetoresistive strips.

[0061] The third magnetic sensing mechanism includes at least one third magnetoresistive strip, each of which is arranged on the sidewall of the corresponding groove 4. Among the third magnetoresistive strips, the third magnetoresistive strips arranged in the grooves 4 arranged along the first direction extend along the second direction, that is, the axial direction of the third magnetoresistive strip is consistent with the second direction; the third magnetoresistive strips arranged in the grooves 4 arranged along the second direction extend along the first direction, that is, the axial direction of the third magnetoresistive strip is consistent with the first direction. The arrangement direction of the third magnetoresistive strips is consistent with the corresponding groove 4. The third magnetoresistive strips are all arranged along the first direction, or all arranged along the second direction, or partially arranged along the first direction and partially arranged along the second direction. In one embodiment, the third magnetic sensing mechanism includes two third magnetoresistive strips. When the third magnetic sensing mechanism is arranged in the groove 4 arranged along the first direction, the two third magnetic resistance strips are located on the two opposite side walls of the groove 4 along the first direction; when the third magnetic sensing mechanism is arranged in the groove 4 arranged along the second direction, the two third magnetic resistance strips are located on the two opposite side walls of the groove 4 along the second direction.

[0062] In an embodiment of the present invention, the first direction may be perpendicular to the second direction, and the third direction may be perpendicular to a plane formed by the first direction and the second direction.

[0063] In one embodiment, the first direction can be the X-axis direction of the coordinate system, and the first magnetic sensing mechanism can be the X-axis magnetic sensing mechanism 1; the second direction can be the Y-axis direction of the coordinate system, and the second magnetic sensing mechanism can be the Y-axis magnetic sensing mechanism 2; the third direction can be the Z-axis direction of the coordinate system, and the third magnetic sensing mechanism can be the Z-axis magnetic sensing mechanism 3.

[0064] The X-axis magnetic sensing mechanism 1 is used to sense the magnetic field in the X-axis direction and includes at least one X-axis magnetoresistive bar. The Y-axis magnetic sensing mechanism 2 is used to sense the magnetic field in the Y-axis direction and includes at least one Y-axis magnetoresistive bar.

[0065] The Z-axis magnetic sensing mechanism 3 is disposed on the sidewall of the groove 4 to sense the magnetic field in the Z-axis direction. The Z-axis magnetic sensing mechanism 3 includes at least one Z-axis magnetic resistance bar, each of which extends along the X-axis direction, or along the Y-axis direction, or partially along the X-axis direction and partially along the Y-axis direction.

[0066] In addition, at least one pseudo magnetoresistive strip 123 extending along the easy magnetization direction (such as the Y-axis direction) and not connected to the Wheatstone bridge can be provided between the adjacent X-axis magnetoresistive strips and the Z-axis magnetoresistive strips to isolate the magnetic field interference in the X-axis direction and the Z-axis direction (i.e., to isolate the interference between the adjacent X-axis magnetoresistive strips and the Z-axis magnetoresistive strips).

[0067] At least one pseudo magnetoresistive strip 123 extending along the easy magnetization direction (such as the X-axis direction) and not connected to the Wheatstone bridge can be provided between the adjacent Y-axis magnetoresistive strip and the Z-axis magnetoresistive strip to isolate the magnetic field interference in the Y-axis direction and the Z-axis direction (i.e., to isolate the interference between the adjacent Y-axis magnetoresistive strip and the Z-axis magnetoresistive strip).

[0068] Figure 3 This is a schematic plan view of a three-axis magnetic sensor according to an embodiment of the present invention. Figure 3 , and combined with Figure 2 The X-axis magnetic sensing mechanism 1 includes a plurality of first X-axis magnetoresistive strips 1a and / or a plurality of second X-axis magnetoresistive strips 1b. Each first X-axis magnetoresistive strip 1a and each second X-axis magnetoresistive strip 1b extends along a corresponding easy magnetization direction (e.g., the Y-axis direction). The resistance of the first X-axis magnetoresistive strip 1a increases with external magnetic field input, while the resistance of the second X-axis magnetoresistive strip 1b decreases with external magnetic field input. Specifically, in this embodiment, there are two types of X-axis magnetic sensing mechanisms 1. The first X-axis magnetic sensing mechanism includes two first X-axis magnetoresistive strips 1a, and the second X-axis magnetic sensing mechanism includes two second X-axis magnetoresistive strips 1b.

[0069] The Y-axis magnetic sensing mechanism 2 includes a plurality of first Y-axis magnetoresistive strips 2a and / or a plurality of second Y-axis magnetoresistive strips 2b, each of which extends along a corresponding easy magnetization direction (e.g., the X-axis direction). The resistance of the first Y-axis magnetoresistive strips 2a increases with the input of an external magnetic field, while the resistance of the second Y-axis magnetoresistive strips 2b decreases with the input of an external magnetic field. Specifically, in this embodiment, the Y-axis magnetic sensing mechanism 2 has two types: a first Y-axis magnetic sensing mechanism includes two first Y-axis magnetoresistive strips 2a, and a second Y-axis magnetic sensing mechanism includes two second Y-axis magnetoresistive strips 2b.

[0070] The Z-axis magnetic sensing mechanism 3 includes a plurality of first Z-axis magnetoresistive strips 3a and / or a plurality of second Z-axis magnetoresistive strips 3b, each of which extends along a corresponding easy magnetization direction (e.g., some along the X-axis direction and some along the Y-axis direction). The resistance of the first Z-axis magnetoresistive strips 3a increases with the input of an external magnetic field, while the resistance of the second Z-axis magnetoresistive strips 3b decreases with the input of an external magnetic field. Specifically, in this embodiment, there are three types of Z-axis magnetic sensing mechanisms 3: a first Z-axis magnetic sensing mechanism includes two first Z-axis magnetoresistive strips 3a, a second Z-axis magnetic sensing mechanism includes two second Z-axis magnetoresistive strips 3b, and a third Z-axis magnetic sensing mechanism includes one first Z-axis magnetoresistive strip 3a and one second Z-axis magnetoresistive strip 3b.

[0071] Please continue reading Figure 3 The grooves 4 are partially arranged along the X-axis direction and partially arranged along the Y-axis direction.

[0072] In the grooves 4 arranged along the X-axis direction, X-axis magnetic sensing mechanisms 1 are set between adjacent grooves 4, such as a first X-axis magnetic sensing mechanism can be set between some adjacent grooves 4, and a second X-axis magnetic sensing mechanism can be set between some adjacent grooves 4; Z-axis magnetic sensing mechanisms 3 are set in the grooves 4, such as a first Z-axis magnetic sensing mechanism is set in some grooves 4, a second Z-axis magnetic sensing mechanism is set in some grooves 4, and a third Z-axis magnetic sensing mechanism is set in another part of the grooves 4. Specifically, the first X-axis magnetic sensing mechanism is located between the first and third Z-axis magnetic sensing mechanisms, separating the two adjacent grooves 4 corresponding to the first and third Z-axis magnetic sensing mechanisms. The second X-axis magnetic sensing mechanism is located between the second and third Z-axis magnetic sensing mechanisms, separating the two adjacent grooves 4 corresponding to the second and third Z-axis magnetic sensing mechanisms. Furthermore, the first Z-axis magnetoresistive strip 3a of the third Z-axis magnetic sensing mechanism is adjacent to the first X-axis magnetic sensing mechanism, and the second Z-axis magnetoresistive strip 3b of the third Z-axis magnetic sensing mechanism is adjacent to the second X-axis magnetic sensing mechanism. The first Z-axis magnetoresistive strip 3a and the second Z-axis magnetoresistive strip 3b within the corresponding grooves 4 extend along the Y-axis direction, and each first X-axis magnetoresistive strip 1a and each second X-axis magnetoresistive strip 1b extend along the Y-axis direction. In addition, a pseudo magnetoresistive strip 123 extending along the Y-axis direction and not connected to the Wheatstone bridge may be provided between the adjacent first X-axis magnetoresistive strip 1a and the first Z-axis magnetoresistive strip 3a; a pseudo magnetoresistive strip 123 extending along the Y-axis direction and not connected to the Wheatstone bridge may be provided between the adjacent second X-axis magnetoresistive strip 1b and the second Z-axis magnetoresistive strip 3b.

[0073] In the grooves 4 arranged along the Y-axis direction, a Y-axis magnetic sensing mechanism 2 is set between adjacent grooves 4, such as a first Y-axis magnetic sensing mechanism can be set between some adjacent grooves 4, and a second Y-axis magnetic sensing mechanism can be set between some adjacent grooves 4; a Z-axis magnetic sensing mechanism 3 is set in the grooves 4, such as a first Z-axis magnetic sensing mechanism is set in some grooves 4, a second Z-axis magnetic sensing mechanism is set in some grooves 4, and a third Z-axis magnetic sensing mechanism is set in some other grooves 4. Specifically, the first Y-axis magnetic sensing mechanism is located between the first and third Z-axis magnetic sensing mechanisms, separating the two adjacent grooves 4 corresponding to the first and third Z-axis magnetic sensing mechanisms. The second Y-axis magnetic sensing mechanism is located between the second and third Z-axis magnetic sensing mechanisms, separating the two adjacent grooves 4 corresponding to the second and third Z-axis magnetic sensing mechanisms. Furthermore, the first Z-axis magnetoresistive strip 3a of the third Z-axis magnetic sensing mechanism is adjacent to the first Y-axis magnetic sensing mechanism, and the second Z-axis magnetoresistive strip 3b of the third Z-axis magnetic sensing mechanism is adjacent to the second Y-axis magnetic sensing mechanism. The first Z-axis magnetoresistive strip 3a and the second Z-axis magnetoresistive strip 3b within the corresponding grooves 4 extend along the X-axis direction, and each first Y-axis magnetoresistive strip 2a and each second Y-axis magnetoresistive strip 2b extend along the X-axis direction. In addition, a pseudo magnetoresistive strip 123 extending along the X-axis direction and not connected to the Wheatstone bridge may be provided between the adjacent first Y-axis magnetoresistive strip 2a and the first Z-axis magnetoresistive strip 3a; a pseudo magnetoresistive strip 123 extending along the X-axis direction and not connected to the Wheatstone bridge may be provided between the adjacent second Y-axis magnetoresistive strip 2b and the second Z-axis magnetoresistive strip 3b.

[0074] Figure 4 is a plan view of a three-axis magnetic sensor according to another embodiment of the present invention; Figure 4 In another embodiment of the present invention, the grooves 4 are arranged along the Y-axis direction.

[0075] In the grooves 4 arranged along the Y-axis direction, a Y-axis magnetic sensing mechanism 2 is set between adjacent grooves 4, such as a first Y-axis magnetic sensing mechanism can be set between some adjacent grooves 4, and a second Y-axis magnetic sensing mechanism can be set between some adjacent grooves 4; a Z-axis magnetic sensing mechanism 3 is set in the grooves 4, such as a first Z-axis magnetic sensing mechanism is set in some grooves 4, a second Z-axis magnetic sensing mechanism is set in some grooves 4, and a third Z-axis magnetic sensing mechanism is set in some other grooves 4. Specifically, the first Y-axis magnetic sensing mechanism is located between the first and third Z-axis magnetic sensing mechanisms, separating the two adjacent grooves 4 corresponding to the first and third Z-axis magnetic sensing mechanisms. The second Y-axis magnetic sensing mechanism is located between the second and third Z-axis magnetic sensing mechanisms, separating the two adjacent grooves 4 corresponding to the second and third Z-axis magnetic sensing mechanisms. Furthermore, the first Z-axis magnetoresistive strip 3a of the third Z-axis magnetic sensing mechanism is adjacent to the first Y-axis magnetic sensing mechanism, and the second Z-axis magnetoresistive strip 3b of the third Z-axis magnetic sensing mechanism is adjacent to the second Y-axis magnetic sensing mechanism. The first Z-axis magnetoresistive strip 3a and the second Z-axis magnetoresistive strip 3b within the corresponding grooves 4 extend along the X-axis direction, and each first Y-axis magnetoresistive strip 2a and each second Y-axis magnetoresistive strip 2b extend along the X-axis direction. In addition, a pseudo magnetoresistive strip 123 extending along the X-axis direction and not connected to the Wheatstone bridge may be provided between the adjacent first Y-axis magnetoresistive strip 2a and the first Z-axis magnetoresistive strip 3a; a pseudo magnetoresistive strip 123 extending along the X-axis direction and not connected to the Wheatstone bridge may be provided between the adjacent second Y-axis magnetoresistive strip 2b and the second Z-axis magnetoresistive strip 3b.

[0076] Figure 5 This is a schematic plan view of a three-axis magnetic sensor according to another embodiment of the present invention; Figure 5 In another embodiment of the present invention, the grooves 4 are arranged along the X-axis direction.

[0077] In the grooves 4 arranged along the X-axis direction, X-axis magnetic sensing mechanisms 1 are set between adjacent grooves 4, such as a first X-axis magnetic sensing mechanism can be set between some adjacent grooves 4, and a second X-axis magnetic sensing mechanism can be set between some adjacent grooves 4; Z-axis magnetic sensing mechanisms 3 are set in the grooves 4, such as a first Z-axis magnetic sensing mechanism is set in some grooves 4, a second Z-axis magnetic sensing mechanism is set in some grooves 4, and a third Z-axis magnetic sensing mechanism is set in another part of the grooves 4. Specifically, the first X-axis magnetic sensing mechanism is located between the first and third Z-axis magnetic sensing mechanisms, separating the two adjacent grooves 4 corresponding to the first and third Z-axis magnetic sensing mechanisms. The second X-axis magnetic sensing mechanism is located between the second and third Z-axis magnetic sensing mechanisms, separating the two adjacent grooves 4 corresponding to the second and third Z-axis magnetic sensing mechanisms. Furthermore, the first Z-axis magnetoresistive strip 3a of the third Z-axis magnetic sensing mechanism is adjacent to the first X-axis magnetic sensing mechanism, and the second Z-axis magnetoresistive strip 3b of the third Z-axis magnetic sensing mechanism is adjacent to the second X-axis magnetic sensing mechanism. The first Z-axis magnetoresistive strip 3a and the second Z-axis magnetoresistive strip 3b within the corresponding grooves 4 extend along the Y-axis direction, and each first X-axis magnetoresistive strip 1a and each second X-axis magnetoresistive strip 1b extend along the Y-axis direction. In addition, a pseudo magnetoresistive strip 123 extending along the Y-axis direction and not connected to the Wheatstone bridge may be provided between the adjacent first X-axis magnetoresistive strip 1a and the first Z-axis magnetoresistive strip 3a; a pseudo magnetoresistive strip 123 extending along the Y-axis direction and not connected to the Wheatstone bridge may be provided between the adjacent second X-axis magnetoresistive strip 1b and the second Z-axis magnetoresistive strip 3b.

[0078] The size of the external magnetic field will change the magnetization direction of the magnetoresistive strip, thereby changing the angle between the working electrode and the magnetoresistive strip, that is, the angle between the current direction of the magnetoresistive strip and the magnetization direction of the magnetoresistive strip corresponds to the size of the external magnetic field. Each magnetic sensing mechanism is combined to form an independent Wheatstone bridge, and each bridge arm of each Wheatstone bridge is composed of at least one magnetoresistive strip. In one embodiment, a number of magnetoresistive strips with the same induction change in response to the external magnetic field constitute the arms of a Wheatstone bridge, and two groups of bridge arms whose resistance increases with the external magnetic field input and two groups of bridge arms whose resistance decreases with the external magnetic field input together constitute a Wheatstone bridge (such as Figures 6 to 9 shown).

[0079] In one embodiment of the present invention, a set / reset coil 6 is arranged above and / or below each magnetoresistive strip to generate a magnetic field along the magnetic easy axis; and working electrodes are distributed on the upper surface and / or lower surface of the magnetoresistive strip at a set angle to the magnetoresistive strip.

[0080] The set / reset coil 6 determines the initial magnetization direction of the reluctance strip. The power and ground of the Wheatstone bridge circuit, along with the electrode structure above the reluctance strip, determine the direction of the current flowing through the reluctance strip. In the initial state, the ideal angle between the initial magnetization direction and the current direction is 45° (although other values ​​are possible). When an external magnetic field is applied, it changes the magnetization direction of the reluctance strip, thereby altering the angle between the magnetization direction of the reluctance strip and the current flow direction. As the angle increases, the resistance of the reluctance strip decreases, while as the angle decreases, the resistance of the reluctance strip increases.

[0081] In addition, a self-detection coil 5 may be placed in a local area according to the detection magnetic field of the magnetoresistive strip. The self-detection coil 5 is used to generate a magnetic field corresponding to the detection direction of the magnetoresistive strip.

[0082] In one embodiment of the present invention, a pseudo-magnetoresistive strip that does not output a signal in response to an external magnetic field is placed between adjacent magnetoresistive strips; working electrodes are distributed on the upper surface and / or lower surface of the pseudo-magnetoresistive strip at a set angle to the pseudo-magnetoresistive strip; of course, working electrodes at a set angle to the pseudo-magnetoresistive strip may not be provided.

[0083] The present invention further discloses a preparation process of a three-axis magnetic sensor, the preparation process comprising:

[0084] [Step S1] Providing a silicon substrate or a substrate having a circuit;

[0085] [Step S2] forming at least two grooves on the surface of the substrate; sidewalls of the grooves have a set angle with the substrate surface; the grooves are all arranged along the first direction, or are all arranged along the second direction, or are partially arranged along the first direction and partially arranged along the second direction; at least one pair of adjacent grooves arranged along the first direction has an installation space between them, and / or at least one pair of adjacent grooves arranged along the second direction has an installation space between them;

[0086] [Step S3] forming an insulating layer on the surface of the substrate and the trench;

[0087] [Step S4] A first magnetic sensing mechanism and a second magnetic sensing mechanism are formed on the surface of the insulating layer of the substrate; a third magnetic sensing mechanism is formed on the surface of the insulating layer of the groove; and at least one first magnetic sensing mechanism is arranged in an installation space along the first direction and / or at least one second magnetic sensing mechanism is arranged in an installation space along the second direction; the first magnetic sensing mechanism, the second magnetic sensing mechanism and the third magnetic sensing mechanism all contain magnetic materials; each first magnetic sensing mechanism is used to sense a magnetic field in a first direction, each second magnetic sensing mechanism is used to sense a magnetic field in a second direction, and each third magnetic sensing mechanism is used to sense a magnetic field in a third direction; the first direction and the second direction can form a plane, and the plane corresponds to the surface of the substrate, and the third direction intersects with the surface of the substrate.

[0088] In one embodiment, the first direction can be the X-axis direction of the coordinate system, and the first magnetic sensing mechanism can be the X-axis magnetic sensing mechanism; the second direction can be the Y-axis direction of the coordinate system, and the second magnetic sensing mechanism can be the Y-axis magnetic sensing mechanism; the third direction can be the Z-axis direction of the coordinate system, and the third magnetic sensing mechanism can be the Z-axis magnetic sensing mechanism.

[0089] In one embodiment of the present invention, the magnetic material is selected from any one of anisotropic magnetoresistance material, giant magnetoresistance material and tunnel magnetoresistance material; when forming the magnetic material, a magnetic field is simultaneously applied to the substrate for annealing to induce the magnetization direction of the magnetic material and enhance the magnetic properties of the magnetic material.

[0090] In one embodiment of the present invention, step S4 further includes:

[0091] [Step S41] Forming a dielectric layer on the magnetic material surfaces of the first magnetic sensing mechanism, the second magnetic sensing mechanism, and the third magnetic sensing mechanism;

[0092] [Step S42] forming a through hole in the dielectric layer on the surface of the magnetic material;

[0093] [Step S43] forming a continuous electrode layer on the substrate surface and the trench sidewalls;

[0094] [Step S44] Patterning the electrode layer to form a working electrode on the surface of the magnetic material; forming a through hole in the dielectric layer on the surface of the magnetic material enables the magnetic material to contact the subsequently formed working electrode.

[0095] In addition, the preparation process may further comprise one or more of the following steps:

[0096] Lead ends are respectively provided on the substrate surface and at both ends of the magnetoresistive strip in the groove;

[0097] A self-detection coil is provided at the bottom of the groove, below the substrate and below the magnetic sensing mechanism;

[0098] A set coil and / or a reset coil are arranged on the top of the groove, above the substrate and above the magnetic sensing mechanism.

[0099] In summary, the three-axis magnetic sensor and its manufacturing process proposed in the present invention can reduce process processing errors, increase the process window, and improve the overall yield of the product.

[0100] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned 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 description and application of the present invention here are illustrative and are not intended to limit the scope of the present invention to the above-described embodiments. The effects or advantages involved in the embodiments may not be embodied in the embodiments due to interference from various factors, and the description of the effects or advantages is not used to limit the embodiments. Variations and changes to the embodiments disclosed here are possible, and the replacement of the embodiments and various equivalent components are well known to those of ordinary skill in the art. It should be clear to those skilled in the art that the present invention can be implemented in other forms, structures, arrangements, proportions, and with other components, materials, and parts without departing from the spirit or essential characteristics of the present invention. Other variations and changes can be made to the embodiments disclosed here without departing from the scope and spirit of the present invention.

Claims

1. A three-axis magnetic sensor, characterized in that: The three-axis magnetic sensor comprises: a substrate, wherein a surface portion of the substrate is recessed to form at least two grooves; At least one first magnetic sensing mechanism, configured to sense a magnetic field in a first direction; at least one second magnetic sensing mechanism for sensing a magnetic field in a second direction; and at least two third magnetic sensing mechanisms for sensing a magnetic field in a third direction; The first direction and the second direction can form a plane, and the plane corresponds to the surface of the substrate, and the third direction intersects with the surface of the substrate; each of the grooves is arranged along the first direction, or is arranged along the second direction, or is partially arranged along the first direction and partially arranged along the second direction; the first magnetic sensing mechanism and the second magnetic sensing mechanism are both arranged on the surface of the substrate, and the third magnetic sensing mechanism is arranged in the groove, and each of the third magnetic sensing mechanisms corresponds to each of the grooves one by one; at least one pair of adjacent grooves arranged along the first direction is separated by at least one first magnetic sensing mechanism, and / or at least one pair of adjacent grooves arranged along the second direction is separated by at least one second magnetic sensing mechanism; The first magnetic sensing mechanism includes at least one first magnetoresistive strip, each of which extends along the second direction; the second magnetic sensing mechanism includes at least one second magnetoresistive strip, each of which extends along the first direction; the third magnetic sensing mechanism includes at least one third magnetoresistive strip, each of which is disposed on a sidewall of a corresponding groove; each of the third magnetoresistive strips extends along the first direction, or extends along the second direction, or partially extends along the first direction and partially extends along the second direction; A pseudo magnetoresistive strip not connected to a Wheatstone bridge is provided between the adjacent first magnetoresistive strip and the third magnetoresistive strip, and / or a pseudo magnetoresistive strip not connected to a Wheatstone bridge is provided between the adjacent second magnetoresistive strip and the third magnetoresistive strip.

2. The three-axis magnetic sensor according to claim 1, wherein: A set / reset coil is arranged above or / and below each of the magnetoresistive strips to generate a magnetic field along the easy magnetization axis; a working electrode is distributed on the upper surface or / and lower surface of the magnetoresistive strip and forms a set angle with the magnetoresistive strip.

3. The three-axis magnetic sensor according to claim 1, wherein: The magnetic sensing mechanisms are respectively combined to form a Wheatstone bridge, and each bridge arm of each Wheatstone bridge is composed of at least one magnetoresistive strip; Several magnetoresistive strips with the same inductive change in response to external magnetic field form the arms of a Wheatstone bridge. A Wheatstone bridge includes two groups of arms whose resistance increases with the input of external magnetic field and two groups of arms whose resistance decreases with the input of external magnetic field.

4. The three-axis magnetic sensor according to claim 1, wherein: A self-detection coil is placed in a local area according to the detection magnetic field of the magnetoresistive strip, and the self-detection coil is used to generate a magnetic field corresponding to the detection direction of the magnetoresistive strip.

5. A process for preparing the three-axis magnetic sensor according to any one of claims 1 to 4, characterized in that: The preparation process comprises: Providing a silicon base or a substrate having a circuit; At least two grooves are formed on the surface of the substrate; sidewalls of the grooves form a set angle with the substrate surface; the grooves are all arranged along the first direction, or are all arranged along the second direction, or are partially arranged along the first direction and partially arranged along the second direction; at least one pair of adjacent grooves arranged along the first direction has an installation space between them, and / or at least one pair of adjacent grooves arranged along the second direction has an installation space between them; the first direction and the second direction can form a plane, and the plane corresponds to the surface of the substrate; forming an insulating layer on the surface of the substrate and the trench; A first magnetic sensing mechanism and a second magnetic sensing mechanism are formed on the surface of the insulating layer of the substrate; a third magnetic sensing mechanism is formed on the surface of the insulating layer of the groove; at least one first magnetic sensing mechanism is arranged in an installation space along the first direction and / or at least one second magnetic sensing mechanism is arranged in an installation space along the second direction; the first magnetic sensing mechanism, the second magnetic sensing mechanism and the third magnetic sensing mechanism all contain magnetic materials.

6. The preparation process according to claim 5, characterized in that: The preparation process also includes: forming a dielectric layer on the surface of the magnetic material of the first magnetic sensing mechanism, the second magnetic sensing mechanism, and the third magnetic sensing mechanism; forming a through hole in the dielectric layer on the surface of the magnetic material; forming a continuous electrode layer on the substrate surface and the trench sidewalls; The electrode layer is patterned to form a working electrode on the surface of the magnetic material; a through hole formed in the dielectric layer on the surface of the magnetic material enables the magnetic material to contact the subsequently formed working electrode.

7. The preparation process according to claim 5, characterized in that: The magnetic material is selected from any one of anisotropic magnetoresistive material, giant magnetoresistive material and tunnel magnetoresistive material; when forming the magnetic material, a magnetic field is simultaneously applied to the substrate for annealing to induce the magnetization direction of the magnetic material and improve the magnetic properties of the magnetic material.

8. The preparation process according to any one of claims 5 to 7, characterized in that: The preparation process further comprises: Lead ends are respectively provided on the substrate surface and at both ends of the magnetoresistive strip in the groove; A self-detection coil is provided at the bottom of the groove, below the substrate and below the magnetic sensing mechanism; A set coil and / or a reset coil are arranged on the top of the groove, above the substrate and above the magnetic sensing mechanism.

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