WO2023087884A1

WO2023087884A1 - Magnetic sensor and manufacturing method therefor

Info

Publication number: WO2023087884A1
Application number: PCT/CN2022/119594
Authority: WO
Inventors: 刘恩隆; 何世坤
Original assignee: 浙江驰拓科技有限公司
Priority date: 2021-11-22
Filing date: 2022-09-19
Publication date: 2023-05-25
Also published as: CN116156996A

Abstract

A magnetic sensor and a manufacturing method therefor. The magnetic sensor comprises: a chip provided with a bottom electrode and a device group disposed on the chip, the device group comprising a first magnetic tunnel junction device electrically connected to the bottom electrode; a wiring layer disposed above the first magnetic tunnel junction device; a second magnetic tunnel junction device and a second mask layer disposed at the upper surface of the wiring layer and stacked in sequence, magnetic moment directions of reference layers in the first magnetic tunnel junction device and the second magnetic tunnel junction device being parallel and opposite; a top electrode disposed at the upper surface of the second mask layer; and a signal leading-out part connected to the wiring layer. The first magnetic tunnel junction device and the second magnetic tunnel junction device are distributed in a vertical direction, which can reduce the area of a magnetic sensor, and the magnetic moment directions of the reference layers in the two magnetic tunnel junction devices are parallel and opposite, so that the resistances of the two devices vary inversely in the same magnetic field; that is, the first magnetic tunnel junction device and the second magnetic tunnel junction device are formed on the same chip, so that a Wheatstone half-bridge can be formed without requiring a special process is not needed, and the method is very simple.

Description

A magnetic sensor and its manufacturing method

This application claims the priority of the Chinese patent application with the application number 202111386714.7 and the title of the invention "a magnetic sensor and its manufacturing method" submitted to the China Patent Office on November 22, 2021, the entire contents of which are incorporated by reference in this application middle.

technical field

The present application relates to the technical field of magnetic sensors, in particular to a magnetic sensor and a manufacturing method thereof.

Background technique

At present, the magnetic sensor is basically prepared by using the Tunneling Magnetoresistance (TMR) effect of the Magnetic Tunneling Junction (MTJ), and it is set in the form of a Wheatstone bridge (full bridge or half bridge). To improve the sensitivity of the induced magnetic field.

In the preparation of existing magnetic sensors, MTJ devices with a specific resistance-magnetic field change mode need to be prepared first, and then multiple identical MTJ devices are connected in series to form a single arm of a Wheatstone bridge. Because the working principle of the Wheatstone bridge requires that the output signals of devices with different bridge arms change in opposite directions with the external magnetic field. In order to realize the form of a full bridge or a half bridge, it is necessary to simultaneously obtain MTJ devices with opposite resistance-magnetic field change modes and integrate them together to form different single arms of the Wheatstone bridge.

At present, one process can only produce MTJ devices with the same output signal change trend. There are two ways to obtain MTJ devices with opposite resistance-magnetic field change modes. One is to design two MTJ growth processes and deposit them at different positions on the chip. MTJ devices, to obtain MTJ devices with opposite characteristics, the area of the magnetic sensor is larger, and the process steps are more and more complicated; the other is to use only one MTJ growth process to grow the same MTJ device, and the MTJ devices in different regions of the chip are Magnetization or annealing in a magnetic field in the opposite direction to obtain an MTJ device with opposite characteristics results in a larger area of the magnetic sensor and it is difficult to precisely control the range of the magnetic field.

Therefore, how to solve the above technical problems should be the focus of those skilled in the art.

Contents of the invention

The purpose of this application is to provide a magnetic sensor and its manufacturing method, so as to reduce the area of the magnetic sensor and simplify the process flow.

In order to solve the above technical problems, the application provides a magnetic sensor, including a chip provided with a bottom electrode, and a device group disposed on the chip, the device group comprising:

a first magnetic tunnel junction device electrically connected to the bottom electrode;

a wire layer disposed above the first magnetic tunnel junction device;

The second magnetic tunnel junction device and the second mask layer are arranged on the upper surface of the wire layer and stacked in sequence, and the magnetic moment direction of the reference layer in the first magnetic tunnel junction device and the second magnetic tunnel junction device is parallel and the opposite;

a top electrode disposed on the upper surface of the second mask layer;

A signal lead-out part connected to the wire layer.

Optionally, the long axis directions of the first magnetic tunnel junction device and the second magnetic tunnel junction device are the same.

Optionally, the shapes of the first magnetic tunnel junction device and the second magnetic tunnel junction device are elliptical cylinders.

Optionally, also include:

a first mask layer disposed on the upper surface of the first magnetic tunnel junction device;

A first insulating layer disposed around the first magnetic tunnel junction device and flush with the first mask layer.

Optionally, also include:

A second insulating layer disposed around the second magnetic tunnel junction device and flush with the second mask layer; the signal lead-out part penetrates through the second insulating layer.

Optionally, when the number of the device groups is multiple, a plurality of the device groups form a Wheatstone half bridge, and a first preset number of the first magnetic tunnel junction devices in the Wheatstone half bridge are connected in series A second preset number of the second magnetic tunnel junction devices is connected in series, and the first preset number and the second preset number are both smaller than the number of the device groups.

Optionally, when the number of the device groups is multiple, a plurality of the device groups form a Wheatstone full bridge, and the Wheatstone full bridge includes a parallel first half bridge and a second half bridge, and the first A third preset number of the first magnetic tunnel junction devices in the half bridge and the second half bridge are connected in series, and a fourth preset number of the second magnetic tunnel junction devices are connected in series.

The present application also provides a method for manufacturing a magnetic sensor, including:

forming a bottom electrode on the chip;

preparing a first magnetic tunnel junction device electrically connected to the bottom electrode on the upper surface of the bottom electrode;

forming a wire layer over the first magnetic tunnel junction device;

preparing sequentially stacked second magnetic tunnel junction devices and a second mask layer on the upper surface of the wire layer;

forming a top electrode on the upper surface of the second mask layer;

preparing a signal lead-out part connected to the wire layer;

Use the first magnetic field to magnetize the first magnetic tunnel junction device and the second magnetic tunnel junction device, so that the magnetic moment of the reference layer in the first magnetic tunnel junction device and the second magnetic tunnel junction device parallel and identical in direction;

The first magnetic tunnel junction device or the second magnetic tunnel junction device is magnetized by using a second magnetic field that is opposite to the first magnetic field and has different magnitudes, so that the device magnetized by the second magnetic field The magnetic moment direction of the reference layer is parallel and opposite to that of the reference layer of the device not magnetized by the second magnetic field, resulting in a magnetic sensor.

Optionally, preparing a first magnetic tunnel junction device electrically connected to the bottom electrode on the upper surface of the bottom electrode includes:

preparing a first magnetic tunnel junction device to be processed on the upper surface of the bottom electrode, and forming a first mask layer on the upper surface of the first magnetic tunnel junction device to be processed;

Using the first mask layer as a mask, the first magnetic tunnel junction device to be processed is etched to form the first magnetic tunnel junction device.

Optionally, when etching the wire layer to be processed to form the wire layer, the etching stops to the upper surface of the wire layer to be processed.

A magnetic sensor provided by the present application includes a chip provided with a bottom electrode, and a device group provided on the chip, the device group including: a first magnetic tunnel junction device electrically connected to the bottom electrode; The wire layer arranged above the first magnetic tunnel junction device; the second magnetic tunnel junction device and the second mask layer arranged on the upper surface of the wire layer and stacked in sequence, the first magnetic tunnel junction device and the The direction of the magnetic moment of the reference layer in the second magnetic tunnel junction device is parallel and opposite; the top electrode arranged on the upper surface of the second mask layer; the signal lead-out part connected with the wire layer.

It can be seen that the device group in the magnetic sensor of the present application is directly arranged on the chip, and the first magnetic tunnel junction device and the second magnetic tunnel junction device in the device group are distributed in the vertical direction, which can reduce the area of the magnetic sensor; The magnetic moment directions of the reference layer in the tunnel junction device and the second magnetic tunnel junction device are parallel and opposite, so that the resistance of the first magnetic tunnel junction device and the second magnetic tunnel junction device change oppositely under the action of the same magnetic field, that is By forming the first magnetic tunnel junction device and the second magnetic tunnel junction device on the same chip, the Wheatstone half bridge can be formed without special equipment or process, and is very simple.

In addition, the present application also provides a method for manufacturing a magnetic sensor with the above-mentioned advantages.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the accompanying drawings that need to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings in the following description are only For some embodiments of the present application, those of ordinary skill in the art can also obtain other drawings based on these drawings without creative effort.

FIG. 1 is a schematic structural diagram of a magnetic sensor provided in an embodiment of the present application;

Fig. 2 is a schematic diagram of the relationship between the chip and the z-axis in the embodiment of the present application;

FIG. 3 is a schematic diagram of resistance changes of the first magnetic tunnel junction device and the second magnetic tunnel junction device under the action of a magnetic field in the embodiment of the present application;

FIG. 4 is a schematic diagram of resistance changes of the first magnetic tunnel junction device and the second magnetic tunnel junction device under another magnetic field in the embodiment of the present application;

FIG. 5 is a schematic structural diagram of a Wheatstone half-bridge in a magnetic sensor provided by an embodiment of the present application;

FIG. 6 is a flow chart of a method for manufacturing a magnetic sensor provided in an embodiment of the present application;

7 to 21 are flow charts of a manufacturing process of a magnetic sensor provided in the embodiment of the present application;

FIG. 22 is a schematic diagram of two Wheatstone half bridges connected in parallel to form a Wheatstone full bridge.

Detailed ways

In order to enable those skilled in the art to better understand the solution of the present application, the present application will be further described in detail below in conjunction with the drawings and specific implementation methods. Apparently, the described embodiments are only some of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

In the following description, a lot of specific details are set forth in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described here, and those skilled in the art can do it without departing from the meaning of the present invention. By analogy, the present invention is therefore not limited to the specific examples disclosed below.

As mentioned in the background technology section, in order to obtain MTJ devices with opposite resistance-magnetic field change modes during the fabrication of current magnetic sensors, two MTJ devices with different resistance characteristics are prepared on two chips respectively, and the two chips are Packaging results in a larger area of the magnetic sensor; when preparing MTJ devices with different resistance characteristics on the same chip, it is necessary to design two MTJ growth processes to obtain MTJ devices with opposite characteristics, and the process steps are more and more complicated, or, Using an MTJ growth process to grow the same MTJ device in different regions of the chip, and then form MTJ devices with opposite characteristics through processing, resulting in a large area of the magnetic sensor and it is difficult to precisely control the magnetic field range.

In view of this, the present application provides a magnetic sensor, please refer to FIG. 1 , including a chip provided with a bottom electrode 1, and a device group disposed on the chip, the device group comprising:

A first magnetic tunnel junction device 2 electrically connected to the bottom electrode 1;

a wire layer 5 disposed above the first magnetic tunnel junction device 2;

The second magnetic tunnel junction device 6 and the second mask layer 7 stacked in sequence on the upper surface of the wire layer 5, the reference layer in the first magnetic tunnel junction device 2 and the second magnetic tunnel junction device 6 The directions of the magnetic moments are parallel and opposite;

a top electrode 9 disposed on the upper surface of the second mask layer 7;

A signal lead-out part 10 connected to the wire layer.

Optionally, the magnetic sensor also includes:

a first mask layer 3 disposed on the upper surface of the first magnetic tunnel junction device 2;

A first insulating layer 4 disposed around the first magnetic tunnel junction device 2 and flush with the first mask layer 3. Correspondingly, the wiring layer 5 is located on the upper surfaces of the first mask layer 3 and the first insulating layer 4 .

A second insulating layer 8 disposed around the second magnetic tunnel junction device 6 and flush with the second mask layer 7 ; the signal lead-out portion 10 penetrates through the second insulating layer 8 .

Wherein, the first insulating layer 4 includes:

a first insulating unit layer 41 disposed around the first magnetic tunnel junction device 2;

The second insulating unit layer 42 is disposed on the outer surface of the first insulating unit layer.

The material of the first insulating unit layer may be silicon nitride, and the second insulating unit layer may be an oxide insulating layer such as silicon dioxide or silicon oxynitride.

The second insulating layer 8 includes:

a third insulating unit layer 81 disposed around the second magnetic tunnel junction device 6;

The fourth insulating unit layer 82 is disposed on the outer surface of the third insulating unit layer.

The material of the third insulating unit layer may be silicon nitride, and the fourth insulating unit layer may be an oxide insulating layer such as silicon dioxide or silicon oxynitride.

The conductive film layer of the first mask layer 3 and the second mask layer 7 may be any one of tantalum, tantalum nitride, and titanium nitride.

The first magnetic tunnel junction device 2 includes a seed layer 21, a first pinning layer 22, a first coupling layer 23, a first reference layer 24, a first barrier layer 25, a first free layer 26, and a layer stacked from bottom to top. The first cladding layer 27, the second magnetic tunnel junction device 6 includes a second free layer 61, a second barrier layer 62, a second reference layer 63, a second coupling layer 64, and a second pinning layer 65 stacked from bottom to top and a second cover layer 66 .

The material of the seed layer 21 includes but not limited to ruthenium, platinum, and nickel-chromium alloy; the first pinning layer 22 and the second pinning layer 65 can be cobalt-iron-boron alloys, cobalt, and cobalt/platinum multilayer films of different compositions. , cobalt/nickel multilayer film, etc., wherein, when it is a multilayer film structure, the number of repetitions in the first pinning layer 22 and the second pinning layer 65 can be different or the same; the first coupling layer 23 and the second coupling layer The material of 64 includes but not limited to ruthenium, iridium, rhodium; the material of the first barrier layer 25 and the second barrier layer 62 can be magnesium oxide, aluminum oxide, gallium magnesium oxide, etc.; the first reference layer 24 and the second reference layer The material of layer 63 can be the cobalt-iron-boron alloy of different composition; The first free layer 26 and the first free layer 26 materials can be the cobalt-iron-boron alloy of different composition and relevant material, the first free layer 26 and the second free layer The thickness of 61 is between 1.5 nanometers and 3 nanometers; the materials of the first covering layer 27 and the second covering layer 66 can be magnesium oxide, tantalum, tungsten, molybdenum, cobalt-iron-boron alloys of different components, ruthenium, tantalum, ruthenium/ Tantalum multilayer film, etc. The thickness of the first barrier layer 25 and the second barrier layer 62 is determined by the width of the first magnetic tunnel junction device 2 and the second magnetic tunnel junction device 6 and the required resistance of the single arm of the Wheatstone bridge. Generally, the first The thickness of the barrier layer 25 and the second barrier layer 62 is between 1 nanometer and 3 nanometers.

The first free layer 26 and the second free layer 61 have in-plane magnetic anisotropy, the first coupling layer 23, the second coupling layer 64, the first barrier layer 25, the second barrier layer 62, the seed layer 21 , the first cladding layer 27 and the second cladding layer 66 have no magnetism, and the first pinning layer 22 , the second pinning layer 65 , the first reference layer 24 and the second reference layer 63 have out-of-plane magnetic anisotropy.

The magnetic moment directions of the reference layers in the first magnetic tunnel junction device 2 and the second magnetic tunnel junction device 6 are parallel and opposite, that is, the magnetic moment directions of the first reference layer 24 and the second reference layer 63 are parallel and opposite, so that the first The magnetic tunnel junction device 2 and the second magnetic tunnel junction device 6 have opposite resistance changes under the same magnetic field. The directions of the magnetic moments of the first pinned layer 22 and the second pinned layer 65 are opposite, which can be realized by applying magnetic fields of different magnitudes and opposite directions but perpendicular to the plane of the chip for magnetization. Due to interlayer coupling, the first reference layer 24 The directions of the magnetic moments of the second reference layer 63 and the first pinned layer 22 and the second pinned layer 65 are respectively opposite, so the directions of the magnetic moments of the first reference layer 24 and the second reference layer 63 are also opposite.

When the first reference layer 24 and the second reference layer 63 are flipped under the magnetic field perpendicular to the chip surface, the resistance of the first magnetic tunnel junction device 2 and the second magnetic tunnel junction device 6 is opposite to the change mode of the magnetic field, thereby realizing the benefit Stone half bridge.

Please refer to FIG. 2 and FIG. 3, the z axis is perpendicular to the chip surface, when the magnetic field direction is -z, the magnetic moment direction of each layer with magnetism in the first magnetic tunnel junction device 2 and the second magnetic tunnel junction device 6 is shown in the figure 3, at this time, the free layer magnetic moment of the first magnetic tunnel junction is parallel to the magnetic moment of the first reference layer 24, showing a low resistance value, and the free layer magnetic moment of the second magnetic tunnel junction is parallel to the second reference layer 24 magnetic moment. The magnetic moment of layer 63 is in an antiparallel state, showing high and low resistance values; when the magnetic field direction turns to +z, the magnetic moment of the free layer of the first magnetic tunnel junction and the magnetic moment of the first reference layer 24 are in an antiparallel state, showing high resistance value, the magnetic moment of the free layer of the second magnetic tunnel junction is parallel to the magnetic moment of the second reference layer 63, showing a low resistance value; thereby realizing two opposite resistance-magnetic field response modes in the same structure, that is, in situ A half-bridge structure of a Wheatstone bridge is realized. At this time, the magnetic sensor can sense the magnetic field in the z direction, that is, the direction perpendicular to the upper surface of the chip.

Please refer to FIG. 4, when the magnetic field direction is perpendicular to the z-axis, for example, parallel to the x-axis or y-axis, the magnetic moment direction of each magnetic layer in the first magnetic tunnel junction device 2 and the second magnetic tunnel junction device 6 is shown in FIG. 4 As shown in , when the magnetic moment of the free layer of the first magnetic tunnel junction is parallel to the magnetic moment of the first reference layer 24, showing a low resistance value, the magnetic moment of the free layer of the second magnetic tunnel junction and the magnetic moment of the second reference layer 63 The moments are in an antiparallel state, showing high and low resistance values; when the direction of the magnetic field is turned 180°, the free layer magnetic moments of the first magnetic tunnel junction and the first reference layer 24 are in an antiparallel state, showing high resistance values, and the second The magnetic moment of the free layer of the magnetic tunnel junction is parallel to the magnetic moment of the second reference layer 63 , showing low resistance. At this time, the magnetic sensor can sense the magnetic fields in the x and y directions, that is, the directions parallel to the upper surface of the chip.

The second magnetic tunnel junction device 6 may or may not overlap with the first magnetic tunnel junction device 2 in a direction perpendicular to the chip, which is not limited in this application. When overlapping, it will not affect the signal extraction.

It should be noted that, in this application, the shapes of the first magnetic tunnel junction device 2 and the second magnetic tunnel junction device 6 are not limited, and can be set by themselves. The long axis directions of the first magnetic tunnel junction device 2 and the second magnetic tunnel junction device 6 are the same. For example, the shapes of the first magnetic tunnel junction device 2 and the second magnetic tunnel junction device 6 may be cylindrical or elliptical. When it is cylindrical, the width of the first magnetic tunnel junction device 2 and the second magnetic tunnel junction device 6 is the diameter, and when it is an elliptical cylinder, the width of the first magnetic tunnel junction device 2 and the second magnetic tunnel junction device 6 long or short diameter. The major axis width of the elliptical cylinder is generally between 1 micron and 20 microns, and the minor axis width is generally 0.1 micron to 10 microns; the diameter of the cylindrical device is generally 0.1 micron to 10 microns.

Further, the shape of the first magnetic tunnel junction device 2 and the second magnetic tunnel junction device 6 is an elliptical cylinder, and the long axis direction of the first magnetic tunnel junction device 2 and the second magnetic tunnel junction device 6 same. For example, the long axis directions of the first magnetic tunnel junction device 2 and the second magnetic tunnel junction device 6 are both parallel to the z-axis, or both are parallel to the x-axis.

The absolute value of the width of the first magnetic tunnel junction device 2 and the second magnetic tunnel junction device 6 is determined by the resistance value required by the Wheatstone bridge, and the width difference is determined by the width (diameter) of the signal lead-out part 10 .

The wire layer 5 is a metal wire layer, and the thickness of the wire layer 5 can be between 1 nanometer and 100 nanometers. The material of the metal wire layer is any one or any combination of cobalt, tungsten, ruthenium, molybdenum, and tantalum.

The material of the bottom electrode 1 can be tantalum nitride or titanium nitride, etc., and the material of the top electrode 9 can also be tantalum nitride, titanium nitride, etc.

The device group in the magnetic sensor of the present application is directly arranged on the chip, and the first magnetic tunnel junction device 2 and the second magnetic tunnel junction device 6 in the device group are distributed in the vertical direction, which can reduce the area of the magnetic sensor; A wire layer 5 is arranged between the tunnel junction device 2 and the second magnetic tunnel junction device 6, the signal lead-out part 10 is connected to the wire layer 5, and the magnetic field of the reference layer in the first magnetic tunnel junction device 2 and the second magnetic tunnel junction device 6 The moment directions are parallel and opposite, so that the resistance of the first magnetic tunnel junction device 2 and the second magnetic tunnel junction device 6 change oppositely under the action of the same magnetic field, that is, by forming the first magnetic tunnel junction device 2 on the same chip and the second magnetic tunnel junction device 6, and the first mask layer 3, the first insulating layer 4, the second mask layer 7 and the second insulating layer 8 can be formed to form a Wheatstone half bridge without special equipment Or Craft, very simple.

On the basis of the above embodiments, in one embodiment of the present application, when the number of the device groups is multiple, the multiple device groups form a Wheatstone half bridge, and the first Wheatstone half bridge in the Wheatstone half bridge A preset number of the first magnetic tunnel junction devices 2 are connected in series, a second preset number of the second magnetic tunnel junction devices 6 are connected in series, the first preset number and the second preset number are less than the set The number of device groups described above.

In this application, there is no limitation on the first preset number and the second preset number, which can be set by themselves.

A plurality of first magnetic tunnel junction devices 2 can be connected in series through preset metal wiring, and a plurality of second magnetic tunnel junction devices 6 can be connected in series. Taking the number of device groups as 5 as an example, the formed Wheatstone half bridge is shown in the figure As shown in 5, from the left, the first magnetic tunnel junction device 2 in the three device groups on the left is connected in series, and from the right, the second magnetic tunnel junction device 6 in the three device groups on the right is connected in series, and the signal is transmitted from the device group in the middle The signal lead-out part 10 in the output.

On the basis of the above-mentioned embodiments, in one embodiment of the present application, when the number of the device groups is multiple, the multiple device groups form a Wheatstone full bridge, and the Wheatstone full bridge includes a parallel connection of the first The half bridge and the second half bridge, the third preset number of the first magnetic tunnel junction devices 2 in the first half bridge and the second half bridge are connected in series, and the fourth preset number of the second The magnetic tunnel junction devices 6 are connected in series.

In this application, there is no limitation on the third preset quantity and the fourth preset quantity, which can be set by themselves.

The structural diagram of the first half bridge and the second half bridge can refer to Figure 4. It should be noted that when the first half bridge and the second half bridge are connected in parallel, the first half bridge and the second half bridge are generally connected head to tail in parallel, as shown in Figure 22.

The present application also provides a manufacturing method of a magnetic sensor, please refer to FIG. 6, the method includes:

Step S101: forming a bottom electrode on the chip.

Step S102: preparing a first magnetic tunnel junction device electrically connected to the bottom electrode on the upper surface of the bottom electrode.

Optionally, this step includes:

Step S1021: preparing a first magnetic tunnel junction device to be processed on the upper surface of the bottom electrode, and forming a first mask layer on the upper surface of the first magnetic tunnel junction device to be processed;

Please refer to FIG. 7 for this step. First prepare the first magnetic tunnel junction device 2' to be processed, then prepare the first mask layer to be processed on the upper surface, and perform photolithography and etching on the first mask layer to be processed to obtain the first Mask layer 3.

The first magnetic tunnel junction device 2' to be processed includes a seed layer, a first pinning layer, a first coupling layer, a first reference layer, a first barrier layer, a first free layer, a first overlay.

Step S1022: using the first mask layer as a mask, etching the first magnetic tunnel junction device to be processed to form the first magnetic tunnel junction device.

Optionally, etching the first magnetic tunnel junction device to be processed to form the first magnetic tunnel junction device includes:

Dry etching is used to etch the first magnetic tunnel junction device to be processed to form the first magnetic tunnel junction device. The dry etching can be ion beam etching or reactive ion etching. The etching method of the first magnetic tunnel junction device to be processed may also be wet etching, which is not specifically limited in this application. During etching in this step, the etching stops at the interface where the bottom electrode is located, or exceeds the interface by 1 nanometer to 10 nanometers.

Please refer to FIG. 8 for a schematic diagram after forming the first magnetic tunnel junction device 2 .

Optionally, after the first magnetic tunnel junction device, it also includes: forming a first insulating layer around the first magnetic tunnel junction device, and the first insulating layer is flush with the upper surface of the first mask layer, specifically including:

Step S201: forming a first insulating unit layer 41 around the first magnetic tunnel junction device, as shown in FIG. 9 ;

Step S202: forming a second insulating unit layer 42 on the outer surface of the first insulating unit layer 41, as shown in FIG. 10 ;

Step S203: use chemical mechanical planarization method to smooth the top surfaces of the first insulating unit layer and the second insulating unit layer until the first mask layer is exposed, as shown in FIG. 11 .

Step S103: forming a wire layer above the first magnetic tunnel junction device.

Step S104: preparing sequentially stacked second magnetic tunnel junction devices and a second mask layer on the upper surface of the wire layer.

Please refer to Fig. 12 to Fig. 14 for this step, form the wire layer 5' to be processed on the upper surface of the first mask layer and the first insulating layer, and prepare the second magnetic tunnel junction device to be processed on the upper surface of the wire layer 5' to be processed , optionally, prepare the second mask layer to be processed on the upper surface of the second magnetic tunnel junction device to be processed, and perform photolithography and etching on the second mask layer to be processed to obtain the second mask layer 7, with the second The mask layer 7 is used as a mask to etch the second magnetic tunnel junction device to be processed to form the second magnetic tunnel junction device.

The second magnetic tunnel junction device to be processed includes a second free layer, a second potential barrier layer, a second reference layer, a second coupling layer, a second pinning layer and a second covering layer stacked from bottom to top.

The manner of etching the second magnetic tunnel junction device to be processed may be ion beam etching or reactive ion etching.

Optionally, after forming the second magnetic tunnel junction device, it also includes:

Forming a third insulating unit layer 81 around the second magnetic tunnel junction device, as shown in FIG. 15 ;

Forming a fourth insulating unit layer 82 on the outer surface of the third insulating unit layer 81, as shown in FIG. 16 ;

Polish the upper surfaces of the third insulating unit layer 81 and the fourth insulating unit layer 82 by chemical mechanical planarization until the second mask layer is exposed to form a pre-treated second insulating layer, as shown in FIG. 17 ;

Form a third mask layer to be processed on the upper surface of the second mask layer and the pre-treated second insulating layer, and perform photolithography and etching according to the metal wiring pattern to form a third mask layer 11, as shown in FIG. 18 , Then the pre-treated second insulating layer and the wire layer to be processed are etched to form the second insulating layer and the wire layer 5 , as shown in FIG. 19 .

Optionally, when etching the pre-treated second insulation layer and the wire layer to be processed, the etching stops to the upper surface of the wire layer to be processed, that is, the etching stops to the interface between the wire layer to be processed and the second insulation layer. However, this application does not specifically limit this. As another implementation method, when etching the pre-treated second insulating layer and the wire layer to be processed, the etching exceeds the interface between the wire layer to be processed and the second insulating layer, and the wire layer to be processed is etched. The etching depth of the wire layer is between 1 nanometer and 30 nanometers.

Step S105: forming a top electrode on the upper surface of the second mask layer.

Please refer to FIG. 20 and FIG. 21 , an interlayer oxide insulating layer 12 is first formed on the third mask layer, and then the chemical mechanical planarization method is used to polish the second mask layer 7 to expose, and the second mask layer 7 form the top electrode.

Step S106: preparing a signal lead-out portion connected to the wire layer.

The through hole can be made by Damascene method, and then metal is deposited in the through hole to form the signal lead-out part, and the structural diagram shown in Figure 1 is obtained, and the signal lead-out part is electrically connected with the wire layer.

Step S107: Using a first magnetic field to magnetize the first magnetic tunnel junction device and the second magnetic tunnel junction device, so that the reference layer in the first magnetic tunnel junction device and the second magnetic tunnel junction device The directions of the magnetic moments are parallel and identical.

Step S108: Magnetize the first magnetic tunnel junction device or the second magnetic tunnel junction device by using a second magnetic field opposite in direction to the first magnetic field and different in size, so that the magnetic tunnel junction device magnetized by the second magnetic field The magnetic moment direction of the reference layer of the device is parallel to and opposite to that of the reference layer of the device not magnetized by the second magnetic field, thereby obtaining a magnetic sensor.

In the prior art, the MTJ devices in different regions of the chip are magnetized or annealed in the magnetic field in the opposite direction to obtain MTJ devices with opposite characteristics, and the range of the magnetic field is difficult to accurately control. In this application, two magnetic fields with opposite directions and different sizes are used. All devices on the chip are magnetized twice to obtain the first magnetic tunnel junction device and the second magnetic tunnel junction device with opposite characteristics, which is very simple and convenient, and can also reduce the area of the magnetic sensor.

In the above embodiment, one device group is taken as an example for illustration. When there are multiple devices, multiple device groups can be formed into Wheatstone half-bridge and full-bridge forms by setting wiring.

Each embodiment in this specification is described in a progressive manner, each embodiment focuses on the difference from other embodiments, and the same or similar parts of each embodiment can be referred to each other. As for the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and for the related part, please refer to the description of the method part.

The magnetic sensor provided by the present application and the manufacturing method thereof have been introduced in detail above. In this paper, specific examples are used to illustrate the principles and implementation methods of the present application, and the descriptions of the above embodiments are only used to help understand the methods and core ideas of the present application. It should be pointed out that those skilled in the art can make several improvements and modifications to the application without departing from the principles of the application, and these improvements and modifications also fall within the protection scope of the claims of the application.

Claims

A kind of magnetic sensor is characterized in that, comprises the chip that is provided with bottom electrode, and is arranged on the device group on described chip, and described device group comprises:

a first magnetic tunnel junction device electrically connected to the bottom electrode;

a wire layer disposed above the first magnetic tunnel junction device;

The second magnetic tunnel junction device and the second mask layer are arranged on the upper surface of the wire layer and stacked in sequence, and the magnetic moment direction of the reference layer in the first magnetic tunnel junction device and the second magnetic tunnel junction device is parallel and the opposite;

a top electrode disposed on the upper surface of the second mask layer;

A signal lead-out part connected to the wire layer.
The magnetic sensor according to claim 1, wherein the long axis directions of the first magnetic tunnel junction device and the second magnetic tunnel junction device are the same.
The magnetic sensor according to claim 2, wherein the shape of the first magnetic tunnel junction device and the second magnetic tunnel junction device is an elliptical cylinder.
The magnetic sensor according to claim 1, further comprising:

a first mask layer disposed on the upper surface of the first magnetic tunnel junction device;

A first insulating layer disposed around the first magnetic tunnel junction device and flush with the first mask layer.
The magnetic sensor according to claim 1, further comprising:

A second insulating layer disposed around the second magnetic tunnel junction device and flush with the second mask layer; the signal lead-out part penetrates through the second insulating layer.
The magnetic sensor according to any one of claims 1 to 5, wherein when the number of said device groups is multiple, a plurality of said device groups form a Wheatstone half-bridge, and in the Wheatstone half-bridge A first preset number of the first magnetic tunnel junction devices are connected in series, a second preset number of the second magnetic tunnel junction devices are connected in series, the first preset number and the second preset number are both less than the set The number of device groups described above.
The magnetic sensor according to any one of claims 1 to 5, wherein when the number of the device groups is multiple, a plurality of the device groups form a Wheatstone full bridge, and the Wheatstone full bridge includes a parallel connection The first half-bridge and the second half-bridge, the first half-bridge and the second half-bridge have a third preset number of the first magnetic tunnel junction devices connected in series, and a fourth preset number of the first magnetic tunnel junction devices Two magnetic tunnel junction devices are connected in series.
A method for manufacturing a magnetic sensor, comprising:

forming a bottom electrode on the chip;

preparing a first magnetic tunnel junction device electrically connected to the bottom electrode on the upper surface of the bottom electrode;

forming a wire layer over the first magnetic tunnel junction device;

preparing sequentially stacked second magnetic tunnel junction devices and a second mask layer on the upper surface of the wire layer;

forming a top electrode on the upper surface of the second mask layer;

preparing a signal lead-out part connected to the wire layer;

Use the first magnetic field to magnetize the first magnetic tunnel junction device and the second magnetic tunnel junction device, so that the magnetic moment of the reference layer in the first magnetic tunnel junction device and the second magnetic tunnel junction device parallel and identical in direction;

The first magnetic tunnel junction device or the second magnetic tunnel junction device is magnetized by using a second magnetic field that is opposite to the first magnetic field and has different magnitudes, so that the device magnetized by the second magnetic field The magnetic moment direction of the reference layer is parallel and opposite to that of the reference layer of the device not magnetized by the second magnetic field, resulting in a magnetic sensor.
The method for manufacturing a magnetic sensor according to claim 8, wherein preparing a first magnetic tunnel junction device electrically connected to the bottom electrode on the upper surface of the bottom electrode comprises:

preparing a first magnetic tunnel junction device to be processed on the upper surface of the bottom electrode, and forming a first mask layer on the upper surface of the first magnetic tunnel junction device to be processed;

Using the first mask layer as a mask, the first magnetic tunnel junction device to be processed is etched to form the first magnetic tunnel junction device.
The manufacturing method of the magnetic sensor according to claim 8 or 9, characterized in that, when etching the wire layer to be processed to form the wire layer, the etching stops to the upper surface of the wire layer to be processed.