Three-dimensional tunneling magnetoresistance sensor and manufacturing method thereof

Abstract

The present invention relates to the field of magnetic sensors, and provides a three-dimensional tunneling magnetoresistance sensor and a manufacturing method thereof. The three-dimensional tunneling magnetoresistance sensor includes at least two identical tunneling magnetoresistance chips. Each tunneling magnetoresistance chip includes a first magnetic sensing unit and a second magnetic sensing unit. The first magnetic sensing unit and the second magnetic sensing unit are formed on the same substrate. The first magnetic sensing unit is used to sense the magnetic field in the horizontal direction, and the second magnetic sensing unit is used to sense the magnetic field in the vertical direction. The two identical tunneling magnetoresistance chips are packaged by flip-chip bonding, so that the first magnetic sensing units of the two tunneling magnetoresistance chips are interconnected face to face, and the second magnetic sensing units of the two tunneling magnetoresistance chips are interconnected face to face, forming a full-bridge structure. The present invention can simultaneously determine the magnetization directions of the TMR structures in three directions through a single preparation process, and adopts flip-chip bonding technology to realize the full-bridge structure of the magnetic sensing units in three directions, reducing the volume of the three-dimensional tunneling magnetoresistance sensor and reducing errors.

Description

Technical Field

[0001] The present invention relates to the field of magnetic sensors, and more particularly to a three-dimensional tunneling magnetoresistance sensor and a manufacturing method thereof. Background Art

[0002] A magnetic sensor is a sensor that can detect the magnetic field intensity. A three-dimensional magnetic sensor can measure the magnetic field intensity in three directions simultaneously, so that the direction and magnitude information of any magnetic field can be obtained. A TMR (Tunnel Magnetoresistance) type sensor uses the tunnel magnetoresistance effect to measure the magnetic field, and has advantages such as high sensitivity and good temperature characteristics, and is widely used in industrial and civilian industries. The TMR sensor has much higher sensitivity than AMR (Anisotropy Magnetoresistance) sensors, GMR (Giant Magnetoresistance) magnetic sensors, and Hall sensors. Preparing a three-dimensional magnetic sensor using the TMR effect can effectively improve the sensitivity of the three-dimensional magnetic sensor and has a very broad application prospect.

[0003] In the prior art solutions, the method for preparing a three-dimensional magnetic sensor using the TMR effect is to arrange three prepared TMR sensors sensitive to a single direction along three mutually perpendicular directions. Two TMR sensors are on one packaging plane, but their sensitive directions are perpendicular to each other, and the third sensor is placed perpendicular to the packaging plane. Since two TMR sensors need to be placed on the same plane, the device area is greatly increased, and the vertically placed TMR sensor will also greatly increase the height of the device. This not only increases the volume of the sensor, but also the direction error generated during the placement of the sensor will seriously affect the performance of the three-dimensional sensor.

[0004] Sensors that utilize the magnetoresistive effect typically fabricate the magnetosensitive elements in the form of a full-bridge structure, which can significantly enhance the sensitivity and temperature stability of the device. The full-bridge structure requires the sensitive directions of the magnetoresistive units on adjacent bridge arms to be opposite. However, the change in magnetoresistance of a TMR-type sensor is due to the relative orientation of the magnetization directions of the free layer and the pinned layer. Therefore, the sensitive direction of the sensor is determined by the magnetization direction of the pinned layer. During the chip fabrication process, the directions of the pinned layers on the same chip are generally the same. Currently, the methods for achieving different magnetization directions of the pinned layers in different regions on a single chip include laser annealing, sequential deposition, and current-induced method. The laser annealing method uses a laser annealing device to pin the magnetization directions of the pinned layers in different regions in opposite directions. However, due to the high cost of the laser annealing device, the production cost is very high. Sequential deposition involves depositing in two steps to grow pinned layers with different magnetization directions successively. However, during the second deposition, it is easy to affect the first layer, ultimately affecting the device performance. The current-induced method is to fabricate a current channel along a certain direction under the magnetoresistive unit and change the direction of the pinned layer by applying a large current. However, this method increases the complexity and consistency of the device. It can be seen that it is difficult for the prior art to fabricate a full-bridge structure TMR sensor that can measure magnetic fields in three directions through a single fabrication process. Summary of the Invention

[0005] To address the above technical deficiencies, the present invention provides a three-dimensional tunneling magnetoresistance sensor and its manufacturing method, which form magnetosensitive units for measuring magnetic fields in three directions on the same substrate, reducing the volume of the three-dimensional tunneling magnetoresistance sensor.

[0006] On the one hand, the present invention provides a three-dimensional tunneling magnetoresistance sensor, including at least two identical tunneling magnetoresistance chips. Each tunneling magnetoresistance chip includes a first magnetosensitive unit and a second magnetosensitive unit. The first magnetosensitive unit and the second magnetosensitive unit are formed on the same substrate. The first magnetosensitive unit is used to sense the magnetic field in the horizontal direction, and the second magnetosensitive unit is used to sense the magnetic field in the vertical direction. Two identical tunneling magnetoresistance chips are packaged in a flip-chip bonding manner, such that the first magnetosensitive units of the two tunneling magnetoresistance chips are interconnected face to face, and the second magnetosensitive units of the two tunneling magnetoresistance chips are interconnected face to face, forming a full-bridge structure.

[0007] In an embodiment of the present invention, the first magnetosensitive unit includes a plurality of magnetosensitive units in the X direction and a plurality of magnetosensitive units in the Y direction; the magnetosensitive unit in the X direction includes a groove formed in the X direction of the substrate, the groove has a first side wall and a second side wall, the first side wall and the second side wall intersect at an angle, and a tunneling magnetoresistance functional layer and an electrode layer are provided on the surfaces of both the first side wall and the second side wall; the magnetosensitive unit in the Y direction includes a groove formed in the Y direction of the substrate, the groove has a first side wall and a second side wall, the first side wall and the second side wall intersect at an angle, and a tunneling magnetoresistance functional layer and an electrode layer are provided on the surfaces of both the first side wall and the second side wall.

[0008] In an embodiment of the present invention, the electrode layers each include a bottom electrode layer and a top electrode layer, the bottom electrode layer is disposed between the side wall of the groove and the tunneling magnetoresistance functional layer, and the top electrode layer is disposed on the tunneling magnetoresistance functional layer.

[0009] In an embodiment of the present invention, a plurality of magnetosensitive units in the X direction are cascaded in sequence, the top electrode layer on the surface of the first side wall of the previous magnetosensitive unit in the X direction is interconnected with the bottom electrode layer on the surface of the first side wall of the next magnetosensitive unit in the X direction, and the bottom electrode layer on the surface of the second side wall of the previous magnetosensitive unit in the X direction is interconnected with the top electrode layer on the surface of the second side wall of the next magnetosensitive unit in the X direction;

[0010] A plurality of magnetosensitive units in the Y direction are cascaded in sequence, the top electrode layer on the surface of the first side wall of the previous magnetosensitive unit in the Y direction is interconnected with the bottom electrode layer on the surface of the first side wall of the next magnetosensitive unit in the Y direction, and the bottom electrode layer on the surface of the second side wall of the previous magnetosensitive unit in the Y direction is interconnected with the top electrode layer on the surface of the second side wall of the next magnetosensitive unit in the Y direction.

[0011] In an embodiment of the present invention, the second magnetosensitive unit includes a plurality of protrusions formed on the substrate, a tunneling magnetoresistance functional layer and an electrode layer are provided on the side wall surface of the protrusion, and the tunneling magnetoresistance functional layer is perpendicular to the substrate surface.

[0012] In an embodiment of the present invention, the electrode layer includes a bottom electrode layer and a top electrode layer, the bottom electrode layer is disposed between the side wall of the protrusion and the tunneling magnetoresistance functional layer, and the top electrode layer is disposed on the surface of the tunneling magnetoresistance functional layer.

[0013] In an embodiment of the present invention, a plurality of second magnetosensitive units are cascaded in sequence, and the bottom electrode layer of the previous second magnetosensitive unit is interconnected with the top electrode layer of the next second magnetosensitive unit.

[0014] In an embodiment of the present invention, the tunneling magnetoresistance functional layer includes a free layer, a barrier layer and a pinned layer from bottom to top.

[0015] On the other hand, the present invention provides a manufacturing method of the above three-dimensional tunneling magnetoresistance sensor, including:

[0016] A boss and a groove are formed on the same substrate. The side wall of the boss is perpendicular to the substrate surface. The groove includes a groove in the X direction and a groove in the Y direction. The first side wall and the second side wall of the groove intersect at an angle.

[0017] Meanwhile, a tunneling magnetoresistance functional layer and an electrode layer are formed on the side wall of the boss and the side wall of the groove.

[0018] A magnetic field perpendicular to the substrate surface is applied to determine the magnetization direction of the tunneling magnetoresistance functional layer, so that the tunneling magnetoresistance functional layer on the side wall of the boss can sense the magnetic field perpendicular to the substrate surface, and the tunneling magnetoresistance functional layer on the side wall of the groove can sense the magnetic field in the plane where the substrate is located, thereby forming a single tunneling magnetoresistance chip.

[0019] Two tunneling magnetoresistance chips are interconnected face to face by using a flip-chip packaging method to form a three-dimensional tunneling magnetoresistance sensor with a full-bridge structure.

[0020] In the embodiment of the present invention, the step of simultaneously forming a tunneling magnetoresistance functional layer and an electrode layer on the side wall of the boss and the side wall of the groove includes:

[0021] The substrate with the boss and the groove is subjected to an oxidation treatment, so that an oxide layer is generated on the upper surface and the side surface of the substrate and the boss as an insulating layer, and an oxide layer is generated on the side wall of the groove and the substrate surface as an insulating layer.

[0022] A bottom electrode layer, a pinned layer, a barrier layer, a free layer, and a top electrode layer are deposited on the surface of the substrate with the insulating layer.

[0023] An etching treatment is performed to retain the bottom electrode layer, the pinned layer, the barrier layer, the free layer, and the top electrode layer on the side wall of the boss and the side wall of the groove, so as to obtain the tunneling magnetoresistance functional layer and the electrode layer.

[0024] In the embodiment of the present invention, the method further includes:

[0025] An oxide layer is deposited on the surface of the tunneling magnetoresistance functional layer and the electrode layer as an insulating layer.

[0026] Contact holes are opened on the upper surface and the side wall of the boss, and contact holes are opened on the side wall of the groove.

[0027] A via treatment is performed on the contact holes to form via metal wires, connecting the bottom electrode layer on the upper surface of the previous boss to the top electrode layer on the side wall of the next boss, connecting the top electrode layer on the first side wall of the previous groove to the bottom electrode layer on the first side wall of the next groove, and connecting the bottom electrode layer on the second side wall of the previous groove to the top electrode layer on the second side wall of the next groove.

[0028] In the embodiment of the present invention, the two tunnel magnetoresistance chips are interconnected face to face by using a flip-chip packaging method, which includes: flipping one tunnel magnetoresistance chip 180° relative to the other tunnel magnetoresistance chip, and interconnecting the two tunnel magnetoresistance chips face to face through bump electrodes.

[0029] In the present invention, a plurality of magnetosensitive units for sensing magnetic fields in the horizontal direction (X and Y directions) and the vertical direction (Z direction) are simultaneously formed on a substrate to obtain a single tunnel magnetoresistance chip. Two identical tunnel magnetoresistance chips are interconnected face to face by using a flip-chip packaging method to form a three-dimensional tunnel magnetoresistance sensor with a full-bridge structure. During the preparation process, a magnetic field perpendicular to the surface of the substrate is applied, and the magnetization directions of the TMR structures in three directions can be simultaneously determined through a single preparation process (annealing process in the magnetic field); the full-bridge structure of the magnetosensitive units in three directions is realized by using flip-chip technology. The formed three-dimensional tunnel magnetoresistance sensor reduces the volume of the three-dimensional tunnel magnetoresistance sensor and reduces errors compared with the prior art method of placing three TMR sensors in three perpendicular directions.

[0030] Other features and advantages of the technical solution of the present invention will be described in detail in the following specific implementation section. Brief Description of the Drawings

[0031] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0032] Figure 1 is a plan view of the three-dimensional tunnel magnetoresistance sensor provided by the embodiment of the present invention;

[0033] Figure 2 is a cross-sectional view of the first magnetosensitive unit of the three-dimensional tunnel magnetoresistance sensor provided by the embodiment of the present invention;

[0034] Figure 3 is a cross-sectional view of the second magnetosensitive unit of the three-dimensional tunnel magnetoresistance sensor provided by the embodiment of the present invention;

[0035] Figure 4 is a schematic diagram of applying an external magnetic field to the first magnetosensitive unit in the embodiment of the present invention;

[0036] Figure 5 is a schematic diagram of flip-chip bonding of two first magnetosensitive units in the embodiment of the present invention;

[0037] Figure 6 is a schematic diagram of flip-chip bonding of two second magnetosensitive units in the embodiment of the present invention;

[0038] Figure 7It is a flowchart of a manufacturing method of a three-dimensional tunneling magnetoresistance sensor provided by an embodiment of the present invention.

[0039] Explanation of reference numerals

[0040] 100 - Substrate, 200 - First magnetosensitive unit, 210 - X - direction magnetosensitive unit, 220 - Y - direction magnetosensitive unit, 211 - Groove, 212 - First side wall, 213 - Second side wall, 214 - Bottom electrode layer, 215 - Tunneling magnetoresistance functional layer, 216 - Top electrode layer, 300 - Second magnetosensitive unit, 301 - Boss, 302 - Bottom electrode layer, 303 - Tunneling magnetoresistance functional layer, 304 - Top electrode layer. Detailed implementation manners

[0041] In order to make the technical solutions and advantages in the embodiments of the present invention clearer and more understandable, the following further elaborates on the exemplary embodiments of the present invention with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than an exhaustive list of all embodiments. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0042] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation to the present invention.

[0043] In the description of the present invention, "first" and "second" are only used for descriptive purposes, and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. The meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined. In the present invention, unless otherwise clearly defined and limited, terms such as "connected" and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, and can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] In the process of implementing the present invention, the inventors found that the method of arranging three TMR sensors in three perpendicular directions to form a three-dimensional tunneling magnetoresistance sensor increases the volume and error of the sensor. And it is difficult to fabricate a TMR sensor with a full-bridge structure capable of measuring magnetic fields in three directions through a single preparation process. Based on this, an embodiment of the present invention provides a three-dimensional tunneling magnetoresistance sensor, which includes at least two identical tunneling magnetoresistance chips. Each tunneling magnetoresistance chip includes a first magnetic sensing unit and a second magnetic sensing unit. The first magnetic sensing unit and the second magnetic sensing unit are formed on the same substrate. The first magnetic sensing unit is used to sense the magnetic field in the horizontal direction, and the second magnetic sensing unit is used to sense the magnetic field in the vertical direction. Two identical tunneling magnetoresistance chips are packaged by flip-chip bonding, so that the first magnetic sensing units of the two tunneling magnetoresistance chips are interconnected face to face, and the second magnetic sensing units of the two tunneling magnetoresistance chips are interconnected face to face, forming a full-bridge structure.

[0045] In the present invention, multiple magnetic sensing units for sensing the magnetic fields in the horizontal direction (X and Y directions) and the vertical direction (Z direction) are formed on a single substrate to obtain a single tunneling magnetoresistance chip. Two identical tunneling magnetoresistance chips are interconnected face to face by flip-chip bonding to form a three-dimensional tunneling magnetoresistance sensor with a full-bridge structure. During the preparation process, a magnetic field perpendicular to the surface of the substrate is applied, and the magnetization directions of the pinned layers of the TMR structures in the three directions can be determined simultaneously through a single annealing process in the magnetic field; the full-bridge structure of the magnetic sensing units in the three directions is realized by using flip-chip bonding technology. The formed three-dimensional tunneling magnetoresistance sensor has a smaller volume and less error compared with the prior art method of arranging three TMR sensors in three perpendicular directions. The technical solution of the present invention will be elaborated in detail below.

[0046] As Figure 1 shown, the three-dimensional tunneling magnetoresistance sensor provided by the embodiment of the present invention. One of the tunneling magnetoresistance chips includes a first magnetic sensing unit 200 and a second magnetic sensing unit 300 formed on the same substrate 100. The first magnetic sensing unit 200 includes a plurality of X-direction magnetic sensing units 210 and a plurality of Y-direction magnetic sensing units 220. The X-direction magnetic sensing units 210 and the Y-direction magnetic sensing units 220 are groove structures, and the X-direction magnetic sensing units 210 and the Y-direction magnetic sensing units 220 are arranged perpendicular to each other, and are respectively used to sense the magnetic fields in the X direction and the Y direction in the same plane. The second magnetic sensing unit 300 is a boss structure, and a plurality of bosses 301 are arranged in an array, and are used to sense the magnetic field in the direction perpendicular to the plane of the substrate 100 (Z direction). This tunneling magnetoresistance chip can realize the measurement of magnetic fields in the X, Y, and Z directions.

[0047] The X-direction magnetosensitive unit 210 and the Y-direction magnetosensitive unit 220 of the first magnetosensitive unit 200 are the same in structure, except for the different directions of their grooves 211. The X-direction magnetosensitive unit 210 includes a groove formed in the X direction of the substrate, and the Y-direction magnetosensitive unit 220 includes a groove formed in the Y direction of the substrate.

[0048] As Figure 2 shown, for the X-direction magnetosensitive unit 210 or the Y-direction magnetosensitive unit 220, its groove 211 has a first side wall 212 and a second side wall 213. The first side wall 212 and the second side wall 213 intersect at a certain angle, or the first side wall 212 and the second side wall 213 are perpendicular to each other at a 90° angle. The surfaces of the first side wall 212 and the second side wall 213 are both provided with a tunneling magnetoresistance functional layer 215 and an electrode layer. The electrode layer includes a bottom electrode layer 214 and a top electrode layer 216. The bottom electrode layer 214 is disposed between an insulating layer (not shown in the drawing) on the side wall of the groove 211 and the tunneling magnetoresistance functional layer 215, and the top electrode layer 216 is disposed on the tunneling magnetoresistance functional layer 215. Among them, the tunneling magnetoresistance functional layer 215 includes a free layer, a barrier layer, and a pinned layer (not shown in the drawing) from bottom to top.

[0049] In an embodiment, multiple X-direction magnetosensitive units 210 are cascaded in sequence. The top electrode layer 216 on the surface of the first side wall 212 of the previous X-direction magnetosensitive unit 210 is interconnected with the bottom electrode layer 214 on the surface of the first side wall 212 of the next X-direction magnetosensitive unit 210, and the bottom electrode layer 214 on the surface of the second side wall 213 of the previous X-direction magnetosensitive unit 210 is interconnected with the top electrode layer 216 on the surface of the second side wall 213 of the next X-direction magnetosensitive unit 210. Similarly, multiple Y-direction magnetosensitive units 220 are cascaded in sequence. The top electrode layer 216 on the surface of the first side wall 212 of the previous Y-direction magnetosensitive unit 220 is interconnected with the bottom electrode layer 214 on the surface of the first side wall 212 of the next Y-direction magnetosensitive unit 220, and the bottom electrode layer 214 on the surface of the second side wall 213 of the previous Y-direction magnetosensitive unit 220 is interconnected with the top electrode layer 216 on the surface of the second side wall 213 of the next Y-direction magnetosensitive unit 220. In a specific embodiment, multiple magnetosensitive units with groove structures are cascaded in sequence. The top electrode layer 216 of the previous magnetosensitive unit is connected to the bottom electrode layer 214 of the next magnetosensitive unit through a metal wire, and the bottom electrode layer 214 of the previous magnetosensitive unit is connected to the top electrode layer 216 of the next magnetosensitive unit through a metal wire. By changing the size of the groove and the number of cascaded grooves (tunneling magnetoresistance functional layers), the resistance value of the first magnetosensitive unit can be adjusted.

[0050] As Figure 3As shown, the second magnetosensitive unit 300 includes a plurality of cuboid or cube bosses 301 formed on the substrate 100. A tunnel magnetoresistance functional layer 303 and an electrode layer are provided on the sidewall surface of the boss 301. The tunnel magnetoresistance functional layer 303 is perpendicular to the surface of the substrate 100. The electrode layer includes a bottom electrode layer 302 and a top electrode layer 304. The bottom electrode layer 302 is located between an insulating layer (not shown in the drawings) on the sidewall of the boss 301 and the tunnel magnetoresistance functional layer 303, and the top electrode layer 304 is provided on the surface of the tunnel magnetoresistance functional layer 303. Among them, the tunnel magnetoresistance functional layer 303 includes a free layer, a barrier layer, and a pinned layer (not shown in the drawings) from bottom to top. In a specific embodiment, a plurality of second magnetosensitive units 300 are cascaded in sequence, and the bottom electrode layer 302 of the previous second magnetosensitive unit 300 is interconnected with the top electrode layer 304 of the next second magnetosensitive unit 300 through a metal wire. By changing the size of the boss and the number of cascaded bosses (tunnel magnetoresistance functional layers), the resistance value of the second magnetosensitive unit can be adjusted.

[0051] The first magnetosensitive unit and the second magnetosensitive unit can be completed on the same chip substrate through a single manufacturing process to obtain a single tunnel magnetoresistance chip, but a full-bridge structure has not been formed yet. In order to form a full-bridge structure with multiple first magnetosensitive units or multiple second magnetosensitive units, the present invention uses a flip-chip bonding method for packaging to form a three-dimensional tunnel magnetoresistance sensor. Specifically, take two identical tunnel magnetoresistance chips, as Figure 5 and Figure 6 shown. One chip is flipped 180° relative to the other chip, and the two chips are interconnected face to face through bump electrodes, that is, the first magnetosensitive units of the two chips are interconnected face to face, and the second magnetosensitive units are interconnected face to face. Since one chip is flipped 180° relative to the other chip, the sensitive directions of the magnetosensitive units in the upper and lower chips are opposite, and multiple magnetosensitive units are interconnected to form a full-bridge structure.

[0052] As Figure 7 shown, the embodiment of the present invention provides a manufacturing method of the above three-dimensional tunnel magnetoresistance sensor. The method includes the following steps:

[0053] S100, forming bosses and grooves on the same substrate;

[0054] S200, simultaneously forming a tunnel magnetoresistance functional layer and an electrode layer on the sidewalls of the bosses and the sidewalls of the grooves;

[0055] S300, applying a magnetic field perpendicular to the surface of the substrate to determine the magnetization direction of the tunnel magnetoresistance functional layer, so that the tunnel magnetoresistance functional layer on the sidewall of the boss can sense the magnetic field perpendicular to the surface of the substrate, and the tunnel magnetoresistance functional layer on the sidewall of the groove can sense the magnetic field in the plane where the substrate is located, forming a single tunnel magnetoresistance chip;

[0056] The S400 uses a flip-chip packaging method to interconnect two tunnel magnetoresistance chips face to face, forming a three-dimensional tunnel magnetoresistance sensor with a full-bridge structure.

[0057] In the above step S100, a cuboid or cube boss array with a certain length, width, and height is prepared on the substrate by etching. A groove array structure is etched on the substrate. The grooves are of two types: grooves along the X direction and grooves along the Y direction. The two side walls (the first side wall and the second side wall) of the groove intersect at a certain angle, or the two side walls are perpendicular to each other at a 90° angle. The side walls of the grooves in the two perpendicular directions form a certain angle with the substrate surface.

[0058] In the above step S200, the substrate with bosses and grooves is oxidized to generate an oxide layer on the upper surface and side surfaces of the substrate and the bosses as an insulating layer, and an oxide layer is generated on the side walls of the grooves and the substrate surface as an insulating layer. The bottom electrode layer, pinned layer, barrier layer, free layer, and top electrode layer in the TMR magnetic sensing unit are deposited by the PVD method, so that the tunnel magnetoresistance functional layer (pinned layer, barrier layer, free layer) completely covers the substrate surface, the side walls and upper surface of the bosses, and the side walls of the grooves. All the layers on the substrate surface are etched away by etching, all the layers except the bottom electrode layer on the upper surface of the bosses are etched away, the tunnel magnetoresistance functional layer on the side walls of the bosses is retained, all the layers except the bottom electrode layer on the substrate surface are removed, all the layers on the side walls of the grooves are retained, and the TMR magnetic sensing units on the side walls of the grooves form a rectangular structure with an aspect ratio greater than 10, and the length direction is along the inclined direction of the side walls of the grooves. Then, another oxide layer is deposited as an insulating layer, contact holes are opened on the upper surface and side walls of the bosses, contact holes are opened on the side walls of the grooves, and the contact holes are processed by a via process through metallization to form via metal wires. The bottom electrode layer on the upper surface of the previous boss is connected to the top electrode layer on the side wall of the next boss, the top electrode layer on the first side wall of the previous groove is connected to the bottom electrode layer on the first side wall of the next groove, and the bottom electrode layer on the second side wall of the previous groove is connected to the top electrode layer on the second side wall of the next groove.

[0059] In a specific embodiment, the resistance value of the TMR magnetic sensing unit can be adjusted by changing the size of the bosses and the number of cascaded bosses, or by changing the size of the grooves and the number of cascaded grooves (tunnel magnetoresistance functional layers).

[0060] In the above step S300, a magnetic field perpendicular to the substrate surface is applied to determine the magnetization direction of the pinned layer in the tunneling magnetoresistance functional layer, so that the magnetization direction of the pinned layer on the sidewall of the convex platform is along the direction perpendicular to the sidewall of the convex platform. Therefore, the tunneling magnetoresistance functional layer on the sidewall of the convex platform can sense the magnetic field in the direction perpendicular to the substrate surface (Z direction); the magnetization direction of the pinned layer on the sidewall of the groove is along the direction perpendicular to the sidewall of the groove. Therefore, the tunneling magnetoresistance functional layers on the two sidewall surfaces of the groove can sense the magnetic field in the plane of the substrate (X, Y directions). Among them, the magnetization direction of the pinned layer on the sidewall of the groove is as Figure 4 shown. Through a single annealing process in a magnetic field, this method can realize the preparation of magnetic-sensitive units in three directions of X, Y, and Z, and form a single tunneling magnetoresistance chip.

[0061] In the above step S400, in order to form a full-bridge structure for the TMR magnetic-sensitive unit, flip chip packaging is used to form a three-dimensional tunneling magnetoresistance sensor. Specifically, take two identical tunneling magnetoresistance chips, such as Figure 5 and Figure 6 shown. One chip is flipped 180° relative to the other chip, and the two chips are interconnected face to face through bump electrodes, that is, the TMR magnetic-sensitive units that sense the horizontal direction (X, Y directions) of the two chips are interconnected face to face, and the TMR magnetic-sensitive units that sense the vertical direction (Z direction) of the two chips are interconnected face to face. Since one chip is flipped 180° relative to the other chip, the sensitive directions of the magnetic-sensitive units in the upper and lower chips are opposite, and a full-bridge structure is formed after interconnection.

[0062] The manufacturing method of the three-dimensional tunneling magnetoresistance sensor provided by the present invention realizes the preparation of magnetic-sensitive units in three directions through a single annealing process in a magnetic field by preparing all TMR magnetic-sensitive units on the sidewalls of convex platforms or grooves. By using flip chip technology, a full-bridge structure of magnetic-sensitive units in three directions is formed, and the volume of the finally prepared sensor hardly increases compared with that of a single tunneling magnetoresistance chip.

[0063] The three-dimensional tunneling magnetoresistance sensor of the present invention includes a TMR magnetic sensitive unit structure for measuring the magnetic field intensity in the vertical direction and a TMR magnetic sensitive unit structure for measuring the magnetic field intensity in the horizontal direction. The TMR magnetic sensitive unit structure for measuring the magnetic field intensity in the vertical direction is formed on an array of rectangular parallelepiped or cubic bosses on a substrate, and the TMR functional layer is prepared on the side walls of the bosses. The side walls of the bosses are perpendicular to the surface direction of the substrate, that is, the Z direction. By changing the size of the bosses and the number of cascaded bosses, the resistance value of the TMR can be adjusted. The TMR magnetic sensitive unit structure for measuring the magnetic field intensity in the horizontal direction is formed on the side walls of grooves on the substrate. There are two directions of the grooves, corresponding to the X direction and the Y direction, and the two directions are perpendicular to each other. The TMR functional layer is rectangular, and the length direction is along the inclined direction of the side wall. The preparation of the TMR magnetic sensitive unit structures for measuring the X, Y, and Z directions of the present invention can be completed by one preparation process. During the preparation process, by applying a magnetic field perpendicular to the surface of the substrate, the magnetization directions of the pinned layers in the TMR magnetic sensitive units in the three directions can be determined simultaneously.

[0064] The optional embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the scope of the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention. In addition, it should be noted that, in the above specific embodiments, the various specific technical features described can be combined in any suitable manner as long as the combination does not violate the idea of the embodiments of the present invention, and it should also be regarded as the content disclosed in the embodiments of the present invention.

Claims

1. A three-dimensional tunneling magnetoresistance sensor, characterized in that Including at least two identical tunneling magnetoresistance chips; Each tunneling magnetoresistance chip includes a first magnetosensitive unit and a second magnetosensitive unit. The first magnetosensitive unit and the second magnetosensitive unit are formed on the same substrate. The first magnetosensitive unit is used to sense the magnetic field in the horizontal direction, and the second magnetosensitive unit is used to sense the magnetic field in the vertical direction; Two identical tunneling magnetoresistance chips are packaged in a flip-chip bonding manner, so that the first magnetosensitive units of the two tunneling magnetoresistance chips are interconnected face to face, and the second magnetosensitive units of the two tunneling magnetoresistance chips are interconnected face to face, forming a full-bridge structure; The first magnetosensitive unit includes a plurality of magnetosensitive units in the X direction and a plurality of magnetosensitive units in the Y direction. The magnetosensitive units in the X direction include grooves formed in the X direction of the substrate, and the magnetosensitive units in the Y direction include grooves formed in the Y direction of the substrate. The grooves have a first side wall and a second side wall, and the first side wall and the second side wall intersect at an angle. Electrode layers are provided on both the surface of the first side wall and the surface of the second side wall of the groove. The electrode layer includes a bottom electrode layer and a top electrode layer; A plurality of magnetosensitive units in the X direction are cascaded in sequence. The top electrode layer located on the surface of the first side wall of the previous magnetosensitive unit in the X direction is interconnected with the bottom electrode layer located on the surface of the first side wall of the next magnetosensitive unit in the X direction, and the bottom electrode layer located on the surface of the second side wall of the previous magnetosensitive unit in the X direction is interconnected with the top electrode layer located on the surface of the second side wall of the next magnetosensitive unit in the X direction; A plurality of magnetosensitive units in the Y direction are cascaded in sequence. The top electrode layer located on the surface of the first side wall of the previous magnetosensitive unit in the Y direction is interconnected with the bottom electrode layer located on the surface of the first side wall of the next magnetosensitive unit in the Y direction, and the bottom electrode layer located on the surface of the second side wall of the previous magnetosensitive unit in the Y direction is interconnected with the top electrode layer located on the surface of the second side wall of the next magnetosensitive unit in the Y direction.

2. The three-dimensional tunneling magnetoresistance sensor according to claim 1, characterized in that Tunneling magnetoresistance functional layers are provided on both the surface of the first side wall and the surface of the second side wall of the groove.

3. The three-dimensional tunneling magnetoresistance sensor according to claim 2, characterized in that, The bottom electrode layer is provided between the side wall of the groove and the tunneling magnetoresistance functional layer, and the top electrode layer is provided on the tunneling magnetoresistance functional layer.

4. The three-dimensional tunneling magnetoresistance sensor according to claim 1, wherein The second magnetosensitive unit includes a plurality of protrusions formed on the substrate. Tunneling magnetoresistance functional layers and electrode layers are provided on the side wall surface of the protrusions, and the tunneling magnetoresistance functional layers are perpendicular to the surface of the substrate.

5. The three-dimensional tunneling magnetoresistance sensor according to claim 4, characterized in that, The electrode layer includes a bottom electrode layer and a top electrode layer. The bottom electrode layer is provided between the side wall of the protrusion and the tunneling magnetoresistance functional layer, and the top electrode layer is provided on the surface of the tunneling magnetoresistance functional layer.

6. The three-dimensional tunneling magnetoresistance sensor according to claim 5, wherein A plurality of second magnetosensitive units are cascaded in sequence. The bottom electrode layer of the previous second magnetosensitive unit is interconnected with the top electrode layer of the next second magnetosensitive unit.

7. The three-dimensional tunneling magnetoresistance sensor according to claim 2 or 4, characterized in that, The tunneling magnetoresistance functional layer includes a free layer, a barrier layer, and a pinned layer from bottom to top.

8. A manufacturing method of a three-dimensional tunneling magnetoresistance sensor, characterized in that, Including: Forming protrusions and grooves on the same substrate. The side walls of the protrusions are perpendicular to the surface of the substrate. The grooves include grooves in the X direction and grooves in the Y direction, and the first side wall and the second side wall of the grooves intersect at an angle; Simultaneously forming tunneling magnetoresistance functional layers and electrode layers on the side walls of the protrusions and the side walls of the grooves. The electrode layer includes a bottom electrode layer and a top electrode layer; Depositing an oxide layer on the surface of the tunneling magnetoresistance functional layer and the electrode layer as an insulating layer; Contact holes are formed on the upper surface and side walls of the boss, and contact holes are formed on the side walls of the groove; The contact holes are processed to form via metal wires, connecting the bottom electrode layer on the upper surface of the previous boss to the top electrode layer on the side wall of the next boss, connecting the top electrode layer on the first side wall of the previous groove to the bottom electrode layer on the first side wall of the next groove, and connecting the bottom electrode layer on the second side wall of the previous groove to the top electrode layer on the second side wall of the next groove; A magnetic field perpendicular to the substrate surface is applied to determine the magnetization direction of the tunneling magnetoresistance functional layer, enabling the tunneling magnetoresistance functional layer on the side wall of the boss to sense the magnetic field perpendicular to the substrate surface direction, and enabling the tunneling magnetoresistance functional layer on the side wall of the groove to sense the magnetic field in the plane where the substrate is located, forming a single tunneling magnetoresistance chip; Two tunneling magnetoresistance chips are interconnected face to face using a flip-chip packaging method to form a three-dimensional tunneling magnetoresistance sensor with a full-bridge structure.

9. The manufacturing method of the three-dimensional tunneling magnetoresistance sensor according to claim 8, characterized in that, The forming of the tunneling magnetoresistance functional layer and the electrode layer on the side walls of the boss and the side walls of the groove simultaneously includes: The substrate with bosses and grooves is oxidized, so that an oxide layer is generated on the upper surface and side surfaces of the substrate and the bosses as an insulating layer, and an oxide layer is generated on the side walls of the grooves and the substrate surface as an insulating layer; A bottom electrode layer, a pinned layer, a barrier layer, a free layer, and a top electrode layer are deposited on the surface of the substrate with the insulating layer; Etching treatment is carried out to retain the bottom electrode layer, the pinned layer, the barrier layer, the free layer, and the top electrode layer on the side walls of the bosses and the side walls of the grooves, obtaining the tunneling magnetoresistance functional layer and the electrode layer.

10. The manufacturing method of the three-dimensional tunneling magnetoresistance sensor according to claim 8, characterized in that, The interconnecting of two tunneling magnetoresistance chips face to face using a flip-chip packaging method includes: One tunneling magnetoresistance chip is flipped 180° relative to the other tunneling magnetoresistance chip, and the two tunneling magnetoresistance chips are interconnected face to face through bump electrodes.

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