阅读说明：本技术 一种磁传感器的制造方法及磁传感器 (Manufacturing method of magnetic sensor and magnetic sensor ) 是由 邹泉波 于 2019-08-02 设计创作，主要内容包括：本发明公开了一种磁传感器的制造方法及磁传感器,包括以下步骤：提供永磁体模板,提供待退火的磁阻单元,将永磁铁模板与磁阻单元配合在一起,并使磁阻图案阵列中的磁阻与永磁体图案阵列中的永磁体一一对应；退火步骤：将贴合后的永磁铁模板与磁阻单元放入退火炉中进行加热、退火,以固定磁阻的钉扎方向。根据本公开的一个实施例,可以降低制造成本,又可以在晶圆上制作多类型的磁传感器。(The invention discloses a manufacturing method of a magnetic sensor and the magnetic sensor, comprising the following steps: providing a permanent magnet template, providing a magnetic resistance unit to be annealed, matching the permanent magnet template and the magnetic resistance unit together, and enabling the magnetic resistance in the magnetic resistance pattern array to correspond to the permanent magnets in the permanent magnet pattern array one by one; and (3) annealing: and (4) putting the bonded permanent magnet template and the magnetic resistance unit into an annealing furnace for heating and annealing so as to fix the pinning direction of the magnetic resistance. According to one embodiment of the disclosure, the manufacturing cost can be reduced, and multi-type magnetic sensors can be manufactured on a wafer.)

1. A method of manufacturing a magnetic sensor, comprising the steps of:

Providing a permanent magnet template comprising a first substrate and an array of permanent magnet patterns disposed on the first substrate;

Providing a magnetoresistive unit to be annealed, wherein the magnetoresistive unit comprises a second substrate and a magnetoresistive pattern array arranged on the second substrate; and the magnetoresistive pattern array corresponds to the permanent magnet pattern array;

An alignment step: matching the permanent magnet template and the magnetic resistance units together, and enabling the magnetic resistance in the magnetic resistance pattern array to correspond to the permanent magnets in the permanent magnet pattern array one by one;

And (3) annealing: placing the bonded permanent magnet template and the magnetic resistance unit into an annealing furnace for heating and annealing so as to fix the pinning direction of the magnetic resistance; the permanent magnet provides an external magnetic field with a fixed pinning direction for the corresponding magnetic resistance.

2. The manufacturing method according to claim 1, wherein a first adhesive layer is provided on the first substrate, and the permanent magnet pattern array is adhered to the first adhesive layer; the second glue layer covers the permanent magnet pattern array; in the aligning step, the permanent magnet template and the magnetic resistance unit are attached together through a second adhesive layer.

3. The manufacturing method according to claim 2, wherein the spacing between the permanent magnet and the reluctance is controlled by the thickness of the second glue layer.

4. the method of claim 2, further comprising the step of planarizing the second glue layer on the first substrate after the annealed permanent magnet template is separated from the magnetoresistive element.

5. the method of claim 2, wherein the annealed permanent magnet form is separated from the magnetoresistive elements, and further comprising the step of peeling off and gumming the second gum layer from the first substrate to reform the second gum layer.

6. The manufacturing method according to claim 1, wherein in the aligning step, the permanent magnet mold plate and the reluctance unit are respectively assembled on a jig.

7. The manufacturing method according to claim 1, wherein the directions of the magnetic fields of the permanent magnets in the permanent magnet pattern array of the permanent magnet template are the same.

8. The manufacturing method according to claim 1, wherein the directions of the magnetic fields of the permanent magnets in the permanent magnet pattern array of the permanent magnet template are different.

9. The method of manufacturing of claim 8, wherein the direction of the magnetic field of the at least one permanent magnet is opposite to the direction of the magnetic field of the at least one permanent magnet.

10. The method of manufacturing of claim 8, wherein the direction of the magnetic field of the at least one permanent magnet is perpendicular to the direction of the magnetic field of the at least one permanent magnet.

11. The manufacturing method according to claim 8, wherein at least two permanent magnets are distributed in a first axial direction and at least two permanent magnets are distributed in a second axial direction;

The magnetic field directions of the at least two permanent magnets distributed in the first axial direction are different from the magnetic field directions of the at least two permanent magnets distributed in the second axial direction;

wherein the content of the first and second substances,

The magnetic field direction of at least one permanent magnet is opposite to that of at least one other permanent magnet;

And at least two permanent magnets distributed in the direction of the second axis, wherein the direction of the magnetic field of at least one permanent magnet is opposite to the direction of the magnetic field of at least one other permanent magnet.

12. the method of manufacturing of claim 1, wherein the step of providing a permanent magnet form comprises:

providing an array of permanent magnets on an original substrate;

Transferring a first portion of the permanent magnets to a first substrate in a predetermined pattern;

Transferring and arranging a second portion of the permanent magnets onto the first substrate according to a predetermined pattern;

Repeating the steps in sequence to form the magnetoresistive pattern array on the first substrate.

13. A magnetic sensor, characterized by being produced according to the production method of claims 1 to 12.

Technical Field

the present invention relates to the field of chips, and more particularly, to a method of fabricating a plurality of magnetoresistors on a substrate; the invention also relates to a magnetic sensor made by the above method.

Background

When a magnetic sensor is manufactured by a wafer-level process, only a single-direction magnetic resistance can be formed on the diaphragm. This is because the pinning direction of the magnetic resistance needs to be fixed in the process of manufacturing the magnetic sensor. The method is characterized in that the same batch of wafers are placed in a magnetic annealing furnace. The magnetic annealing furnace generates a dedicated external magnetic field and heats the wafer. The magnetoresistance is annealed by the dedicated external magnetic field, thereby fixing the pinning direction of the magnetoresistance. The pinning direction of the magnetoresistance is dependent on the direction of the dedicated external magnetic field. Therefore, the pinning directions of the magnetic resistances manufactured in batches on the batch of wafers are the same, so that all the magnetic resistances are simultaneously increased or simultaneously decreased under the action of the working magnetic field, and a full-bridge Wheatstone detection bridge cannot be formed.

However, a full wheatstone bridge is more prone to bi-directional changes (differences) within the same chip to optimize the performance of the detection. In addition, typical magnetic field sensors require multi-axis sensing (e.g., X-axis, Y-axis, and Z-axis), which cannot be fabricated by wafer-level processes, and the fabricated magneto-resistance can only be mounted on the substrate by assembly processes, which reduces sensor performance and increases manufacturing costs due to the large size.

In addition, the magnetic annealing furnace needs to provide a uniform special external magnetic field while providing heat, which makes the magnetic annealing furnace expensive. In addition, when high-temperature annealing is performed, it is difficult to ensure that different magnetoresistances on multiple wafers placed in an annealing furnace can be in a uniform magnetic field, which results in poor consistency of the magnetoresistances after the high-temperature annealing of the same batch.

Disclosure of Invention

An object of the present invention is to provide a new technical solution for a manufacturing method of a magnetic sensor.

According to a first aspect of the present invention, there is provided a method of manufacturing a magnetic sensor, comprising the steps of:

Providing a permanent magnet template comprising a first substrate and an array of permanent magnet patterns disposed on the first substrate;

Providing a magnetoresistive unit to be annealed, wherein the magnetoresistive unit comprises a second substrate and a magnetoresistive pattern array arranged on the second substrate; and the magnetoresistive pattern array corresponds to the permanent magnet pattern array;

An alignment step: matching the permanent magnet template and the magnetic resistance units together, and enabling the magnetic resistance in the magnetic resistance pattern array to correspond to the permanent magnets in the permanent magnet pattern array one by one;

And (3) annealing: placing the bonded permanent magnet template and the magnetic resistance unit into an annealing furnace for heating and annealing so as to fix the pinning direction of the magnetic resistance; the permanent magnet provides an external magnetic field with a fixed pinning direction for the corresponding magnetic resistance.

Optionally, a first adhesive layer is arranged on the first substrate, and the permanent magnet pattern array is adhered to the first adhesive layer; the second glue layer covers the permanent magnet pattern array; in the aligning step, the permanent magnet template and the magnetic resistance unit are attached together through a second adhesive layer.

optionally, the distance between the permanent magnet and the magnetic resistance is controlled by the thickness of the second glue layer.

Optionally, after the annealed permanent magnet template is separated from the magnetoresistive unit, a step of flattening the second glue layer on the first substrate is further included.

Optionally, after the annealed permanent magnet template is separated from the magnetoresistive unit, the method further includes the steps of peeling off the second glue layer on the first substrate and gluing the second glue layer to form the second glue layer again.

optionally, in the aligning step, the permanent magnet template and the reluctance unit are respectively assembled on a jig.

Optionally, in the permanent magnet pattern array of the permanent magnet template, the magnetic field directions of the permanent magnets are the same.

optionally, in the permanent magnet pattern array of the permanent magnet template, the magnetic field directions of the permanent magnets are different.

Optionally, the direction of the magnetic field of the at least one permanent magnet is opposite to the direction of the magnetic field of the at least one permanent magnet.

Optionally, the direction of the magnetic field of the at least one permanent magnet is perpendicular to the direction of the magnetic field of the at least one permanent magnet.

Optionally, the at least two permanent magnets are distributed in a first axial direction and the at least two permanent magnets are distributed in a second axial direction;

The magnetic field directions of the at least two permanent magnets distributed in the first axial direction are different from the magnetic field directions of the at least two permanent magnets distributed in the second axial direction;

Wherein the content of the first and second substances,

the magnetic field direction of at least one permanent magnet is opposite to that of at least one other permanent magnet;

And at least two permanent magnets distributed in the direction of the second axis, wherein the direction of the magnetic field of at least one permanent magnet is opposite to the direction of the magnetic field of at least one other permanent magnet.

Optionally, the step of providing a permanent magnet template comprises:

Providing an array of permanent magnets on an original substrate;

transferring a first portion of the permanent magnets to a first substrate in a predetermined pattern;

Transferring and arranging a second portion of the permanent magnets onto the first substrate according to a predetermined pattern;

Repeating the steps in sequence to form the magnetoresistive pattern array on the first substrate.

According to another aspect of the present invention, there is also provided a magnetic sensor manufactured by the above manufacturing method.

according to one embodiment of the present disclosure, annealing is performed using only annealing furnace heating, and it is no longer necessary to select an expensive furnace that provides both magnetic field and heating. In addition, the manufacturing method of the invention can obtain the magnetic resistances with different pinning directions on the same wafer, so that a Wheatstone detection bridge with better performance can be manufactured on the wafer, and a magnetic sensor for multi-axis detection can also be manufactured.

Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

Fig. 1a to 1h are process flow diagrams of the manufacturing method of the present invention.

Fig. 2a to 2d are schematic structural views of four different embodiments of the permanent magnet template of the present invention.

FIGS. 3 and 4 are schematic diagrams illustrating how the pinning direction is influenced by the direction of the magnetic field in two kinds of magnetoresistive annealing.

Detailed Description

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

The invention provides a manufacturing method of a magnetic sensor, which only uses an annealing furnace for heating for annealing, and does not need to select a furnace which is expensive and provides a magnetic field and heating. In addition, the manufacturing method of the invention can manufacture the magnetic resistances with different pinning directions on the same wafer, so that a Wheatstone detection bridge with better performance can be formed on the wafer, and a magnetic sensor for multi-axis detection can be manufactured.

The manufacturing method of the invention comprises the following steps:

Providing a permanent magnet template, wherein the permanent magnet template comprises a first substrate and a permanent magnet pattern array arranged on the first substrate;

Providing a magnetoresistive unit to be annealed, wherein the magnetoresistive unit comprises a second substrate and a magnetoresistive pattern array arranged on the second substrate; and the magnetoresistive pattern array corresponds to the permanent magnet pattern array;

An alignment step: matching the permanent magnet template and the magnetic resistance units together, and enabling the magnetic resistance in the magnetic resistance pattern array to correspond to the permanent magnets in the permanent magnet pattern array one by one;

and (3) annealing: placing the bonded permanent magnet template and the magnetic resistance unit into an annealing furnace for heating and annealing so as to fix the pinning direction of the magnetic resistance; the permanent magnet provides an external magnetic field with a fixed pinning direction for the corresponding magnetic resistance.

In the above steps, the order of providing the permanent magnet template and providing the magnetoresistive elements to be annealed is not limited. For example, the permanent magnet template may be provided first, followed by the magnetoresistive elements to be annealed; it is also possible to provide the magneto resistive elements to be annealed first and then the permanent magnet templates.

furthermore, the permanent magnet template and the magnetic resistance unit are provided, and the permanent magnet template and the magnetic resistance unit can be manufactured by self; alternatively, an off-the-shelf permanent magnet template may be used, providing a magneto resistive element, which will not be described in detail herein.

The following describes the manufacturing method provided by the present invention in detail with reference to the accompanying drawings.

referring to fig. 1f, a permanent magnet template is provided comprising a first substrate 4 and an array of permanent magnet patterns arranged on the first substrate 4.

In a specific embodiment of the invention, a step of providing a permanent magnet template is recited, as follows:

Providing an array of permanent magnets on an original substrate; the array of permanent magnets on the original substrate 1 may be supplied by another person or may be self-made.

Referring to fig. 1a, an array of permanent magnets is located on an original substrate 1. The original substrate 1 of the present invention may be a wafer. The array of permanent magnets may be formed on the wafer, for example, by deposition, patterning, etc. processes well known to those skilled in the art. Due to process limitations, the magnetic field directions within the permanent magnets in these arrays are uniform, e.g., all toward the right as shown.

In a specific embodiment of the present invention, in order to facilitate the subsequent transfer of the permanent magnet, the original substrate 1 may be made of a light-transmitting material such as sapphire, glass, quartz, etc., so that the original substrate may be selectively transferred by laser lift-off.

The permanent magnet array may be formed directly on the original laser-transparent substrate 1. The permanent magnet can be made of CoPt, FePt or CoCrPt and the like, and the thickness can be 0.1-10 um. For ease of description, two permanent magnets, respectively designated as a first permanent magnet 2 and a second permanent magnet 3, are shown in fig. 1 a. For a person skilled in the art, the array of permanent magnets on the original substrate 1 may be tens, hundreds or even thousands, and will not be described in detail here.

The first permanent magnet 2 and the second permanent magnet 3 are simultaneously fabricated on the original substrate 1, and the magnetic field directions thereof are the same, for example, the internal magnetic field directions thereof are all toward the right in the figure. Namely, the left ends of the first permanent magnet 2 and the second permanent magnet 3 are S poles, and the right ends are N poles.

Transferring a first portion of the permanent magnets to a first substrate in a predetermined pattern; transferring and arranging a second portion of the permanent magnets onto the first substrate according to a predetermined pattern; repeating the steps in sequence to form the magnetoresistive pattern array on the first substrate.

Since the permanent magnet array on the original substrate 1 is fixed, in order to form a designed permanent magnet pattern array, the permanent magnets need to be successively transferred onto another substrate to form a permanent magnet template.

In particular, referring to fig. 1b, a first glue layer 5 is provided, for example, on the first substrate 4. The original substrate 1 and the first adhesive layer 5 of the first substrate 4 are bonded together, so that the first permanent magnet 2 and the second permanent magnet 3 are bonded on the first adhesive layer 5 of the first substrate 4.

the permanent magnet at a predetermined position is detached from the original substrate 1 by selective irradiation with laser light. Referring to fig. 1c, the position of the first permanent magnet 2 is irradiated with laser light from the outside of the original substrate 1, thereby reducing the bonding force or adhesive force between the first permanent magnet 2 and the original substrate 1 to peel the first permanent magnet 2 from the original substrate 1 and to be bonded on the first glue layer 5. Since the second permanent magnet 3 is not irradiated with the laser light, the second permanent magnet 3 remains on the original substrate 1 when the original substrate 1 is separated from the first base 4.

By adjusting the position of the original substrate 1, it is possible to correspond the second permanent magnet 3 to the corresponding position of the first base 4.

Referring to fig. 1d, the original substrate 1 is rotated by 180 °, and the original substrate 1 is combined with the first base 4 after being moved to a corresponding position, so that the second permanent magnet 3 is adhered to the first glue layer 5 of the first base 4. And then selectively irradiating the second permanent magnet 3 by laser to reduce the bonding force of the second permanent magnet 3 with the original substrate 1. When the original substrate 1 is detached from the first base 4, the second permanent magnet 3 is adhered to the first glue layer 5 of the first base 4.

Since the second permanent magnet 3 is rotated by 180 ° with the original substrate 1, the direction of the magnetic field inside the second permanent magnet 3 arranged on the first base 4 is now towards the left in the figure, which is opposite to the direction of the magnetic field inside the first permanent magnet 2, see fig. 1 e.

For those skilled in the art, when the rotation is 90 ° or 270 °, for example, the direction of the magnetic field inside the second permanent magnet 3 will be perpendicular to the direction of the magnetic field inside the first permanent magnet 2, which is not listed here.

The above-described method is repeated in sequence, so that a predetermined permanent magnet template, that is, a predetermined permanent magnet pattern array is formed on the first substrate 4.

The above-described method of such transfer is well known to those skilled in the art. For those skilled in the art, the arrangement of the permanent magnets may be accomplished by the first glue layer 5, or the permanent magnets may be directly bonded on the first substrate 4. In addition, the permanent magnet on the original substrate 1 may be directly transferred to the first base 4, or may be temporarily transferred through a temporary substrate or a temporary adapter, which is selected according to specific needs.

for example, when the magnetic field direction inside the permanent magnet is in the vertical direction, in order to obtain a permanent magnet with an opposite magnetic field direction, a temporary substrate and a temporary adapter are needed to be used for switching part of the permanent magnet, and the switching method belongs to the common knowledge of the skilled person and is not described in detail herein.

in a preferred embodiment of the invention, and with reference to fig. 1f, a second layer of glue 6 covering the array of permanent magnet patterns is also included. The second glue layer 6 may be PDMS, or other high temperature stable viscous adhesives/polymers, and may have a thickness of 1-10 um. The second glue layer 6 is coated on the first glue layer 5 and covers the permanent magnet pattern array, and finally curing or baking is carried out. This second glue layer 6 may serve to protect the array of permanent magnet patterns. While also facilitating the adhesion of the magneto-resistive elements in the subsequent alignment step.

The pattern of the array of permanent magnet patterns on the permanent magnet template is varied and manufactured according to actual needs. Fig. 2a to 2d illustrate schematic diagrams of four pattern arrays.

in the embodiment of fig. 2a, four permanent magnets are provided, denoted first permanent magnet 10, second permanent magnet 11, third permanent magnet 12, fourth permanent magnet 13, respectively. The first permanent magnet 10 and the second permanent magnet 11 are distributed in a first axial direction, for example, an X-axis direction; the third permanent magnet 12 and the fourth permanent magnet 13 are distributed in a second axial direction, for example, the Y-axis direction.

The directions of the magnetic fields inside the first permanent magnet 10 and the second permanent magnet 11 are both in the X-axis direction, and are opposite, for example, the first permanent magnet 10 faces the right direction in the figure, and the second permanent magnet 11 faces the left direction in the figure.

The directions of the internal magnetic fields of the third permanent magnet 12 and the fourth permanent magnet 13 are both in the Y-axis direction, and are opposite, for example, the third permanent magnet 12 faces downward in the figure, and the fourth permanent magnet 13 faces upward in the figure.

Of course, the directions of the internal magnetic fields of the first permanent magnet 10 and the second permanent magnet 11 may also be located in the Y-axis direction; the directions of the magnetic fields inside the third permanent magnet 12 and the fourth permanent magnet 13 can be in the X-axis direction, and are not specifically described here.

In the embodiment of fig. 2b, unlike the embodiment of fig. 2 a: the directions of the internal magnetic fields of the first permanent magnet 10a and the second permanent magnet 11a are both in the X-axis direction, and are the same, for example, the first permanent magnet 10a and the second permanent magnet 11a are both directed rightward in the drawing. The directions of the internal magnetic fields of the third permanent magnet 12a and the fourth permanent magnet 13a are both in the Y-axis direction, and are the same, for example, the third permanent magnet 12a and the fourth permanent magnet 13a are both directed upward in the figure.

In the embodiment of fig. 2c, two permanent magnets, respectively designated as a first permanent magnet 10c, a second permanent magnet 11c, are provided. The first permanent magnet 10c and the second permanent magnet 11c are arranged in the first axial direction, for example, in the X-axis direction. The magnetic field directions inside the first permanent magnet 10c and the second permanent magnet 11c are the same and located in the X-axis direction, and are directed rightward in the drawing, for example.

In the embodiment of fig. 2d, unlike the embodiment of fig. 2 c: the magnetic field directions inside the first permanent magnet 10d and the second permanent magnet 11d are opposite to each other in the X-axis direction. For example, the magnetic field direction inside the first permanent magnet 10d is directed rightward in the drawing; the magnetic field direction inside the second permanent magnet 11d is leftward as viewed in the figure.

The manufacturing method of the present invention further includes providing a magneto-resistive element to be annealed, referring to fig. 1g, the magneto-resistive element includes a second substrate 7 and a magneto-resistive pattern array disposed on the second substrate 7; and the array of magnetoresistive patterns corresponds to the array of permanent magnet patterns.

The second base 7 may be a wafer, such as a silicon substrate or the like. The patterned array of magneto-resistive layers is formed on the silicon substrate by a layer-by-layer deposition, patterning, etc. process well known to those skilled in the art. The magneto-resistance of the invention may be a giant magneto-resistance sensor (GMR), a tunnel magneto-resistance sensor (TMR), an anisotropic magneto-resistance sensor (AMR) or other magneto-resistances known to the person skilled in the art, etc. The electrical performance of the detection mechanism can be ensured by obtaining the detected electrical signal using a high-sensitivity giant magnetoresistive sensor (GMR), a tunnel magnetoresistive sensor (TMR), or an anisotropic magnetoresistive sensor (AMR).

Of course, the different types of magnetoresistance differ from each other in the structure of the layers formed on the silicon substrate, and will not be described in detail here.

The array of magnetoresistive patterns on the second substrate 7 corresponds to the array of permanent magnet patterns, and in fig. 1g, there are two magnetoresistors, which are respectively denoted as a first magnetoresistive 8 and a second magnetoresistive 9. The first magnetoresistance 8 and the second magnetoresistance 9 have not been annealed, and thus the pinning directions of the two magnetoresistance are not fixed.

the manufacturing method of the present invention includes an alignment step: and matching the permanent magnet template and the magnetic resistance units together, and enabling the magnetic resistance in the magnetic resistance pattern array to correspond to the permanent magnets in the permanent magnet pattern array one by one.

For example, the permanent magnet template and the magnetic resistance units can be assembled on the jig respectively through jig assembly, and the permanent magnets on the permanent magnet template correspond to the magnetic resistances in the magnetic resistance units one by one. In addition, when the jig is used for assembling, the distance between the permanent magnet and the magnetic resistance can be controlled, and the specific description is omitted.

In a preferred embodiment of the present invention, the permanent magnet template and the reluctance unit are bonded by the second adhesive layer 6. Referring to fig. 1g, the first magneto-resistance 8 and the second magneto-resistance 9 on the second substrate 7 are adhered to the second glue layer 6. The first magnetic resistance 8 corresponds to the first permanent magnet 2, so that the first permanent magnet 2 can provide an external magnetic field for the first magnetic resistance 8; the second reluctance 9 corresponds to the second permanent magnet 3 so that the second permanent magnet 3 can provide an external magnetic field for the second reluctance 9.

It is further preferred that the first reluctance 8 is located above the central position of the first permanent magnet 2 so that the first reluctance 8 can be located in the uniform magnetic field provided by the first permanent magnet 2. The second reluctance 9 is located above the central position of the second permanent magnet 3 so that the second reluctance 9 can be located in the uniform magnetic field provided by the second permanent magnet 3. In addition, in practical application, the size of the magnetic resistance is far smaller than that of the permanent magnet, so that the magnetic resistance can be further ensured to be positioned in the uniform magnetic field of the permanent magnet.

Preferably, the dimensions and spacing of the components need to be controlled in order to avoid the second permanent magnet 3 affecting the first reluctance 8 and to avoid the first permanent magnet 2 affecting the second reluctance 9. Experiments prove that if the distance between the two permanent magnets is larger than the size of the two permanent magnets, the total magnetic field of the reluctance position is only influenced by the local permanent magnet and is not influenced by the adjacent permanent magnet, and the details are not described herein.

preferably, the distance between the magnetic resistance and the permanent magnet can be controlled through the second glue layer 6, the distance between the magnetic resistance and the permanent magnet is different, the detection range of the magnetic resistance formed after annealing is also different, and the detection range can be adjusted according to the design requirement of the magnetic resistance.

The manufacturing method of the invention comprises the following annealing steps: placing the bonded permanent magnet template and the magnetic resistance unit into an annealing furnace to fix the pinning direction of the magnetic resistance; the permanent magnets provide an external magnetic field of fixed pinning direction for the magnetic resistance corresponding thereto.

referring to fig. 1g, the magnetic field direction inside the first permanent magnet 2 is toward the right in the figure, and the pinning direction after annealing of the first reluctance 8 corresponding thereto is toward the left in the figure; accordingly, the magnetic field direction inside the second permanent magnet 3 is leftward in the drawing, and the pinning direction after annealing of the corresponding second reluctance 9 is rightward in the drawing.

And finally, separating the permanent magnet template from the magnetic resistance units to obtain the magnetic resistance units with opposite pinning directions, and referring to fig. 1 h.

Fig. 3 and 4 are schematic diagrams illustrating two kinds of magnetoresistive pinning directions influenced by the magnetic field direction of the permanent magnet.

In the embodiment of fig. 3, the magnetic field direction in the first permanent magnet 2 is downward as shown in the figure, i.e. the upper end of the first permanent magnet 2 is an S pole and the lower end is an N pole. The magnetic field direction in the second permanent magnet 3 is upward in the figure, that is, the upper end of the second permanent magnet 3 is an N pole, and the lower end is an S pole.

therefore, the direction of the external magnetic field provided by the first permanent magnet 2 is from the N pole to the S pole, and the pinning direction of the first magnetic resistance 8 is from top to bottom under the action of the external magnetic field. Based on a similar principle, the pinning direction of the second reluctance 9 is from bottom to top under the action of the second permanent magnet 3.

In the embodiment of fig. 4, the magnetic field direction in the first permanent magnet 2 is toward the left as shown in the figure, i.e., the right end of the first permanent magnet 2 is the S pole, and the left end is the N pole. The magnetic field direction in the second permanent magnet 3 is toward the right in the figure, that is, the right end of the second permanent magnet 3 is an N pole, and the left end is an S pole.

therefore, the direction of the external magnetic field provided by the first permanent magnet 2 is from the N pole back to the S pole, and the pinning direction of the first magnetic resistance 8 is toward the right in the figure under the action of the external magnetic field. Based on a similar principle, the pinning direction of the second reluctance 9 is toward the left in the drawing under the action of the second permanent magnet 3.

according to the manufacturing method, the external magnetic field is provided for the annealing of the magnetic resistance through the permanent magnet template, so that only a common annealing furnace is needed. In addition, according to the permanent magnet template, various types of magnetoresistive units can be customized, for example, the magnetoresistive units with opposite, vertical or same magnetoresistive pinning directions can be customized, and various different requirements of differential detection, multi-axis detection and the like can be met.

The magnetic sensor manufactured by the method can have a smaller size, and in addition, the magnetic resistances are manufactured in the same batch on the same wafer, the consistency of the magnetic resistances responding to the outside is good, and the initial resistance values are the same.

The permanent magnet template can be reused, and after the annealed permanent magnet template is separated from the reluctance units, the permanent magnet template can be used for annealing the reluctance units of the next batch. In a preferred embodiment of the present invention, after the annealed permanent magnet template is separated from the magnetoresistive element, a step of planarizing the second glue layer 6 on the first substrate 4 is further included. After the permanent magnet template is used for a plurality of times or for a long time, the surface of the second glue layer 6 may have an uneven problem, which affects the consistency of magnetic resistance, so that the surface of the second glue layer 6 can be subjected to a leveling treatment. Such as cleaning, gluing, etc., to improve the flatness of the surface of the second adhesive layer 6 and to increase the viscosity of the second adhesive layer 6.

In another preferred embodiment of the present invention, after the annealed permanent magnet pattern is separated from the magnetoresistive element, the method further comprises the steps of peeling off the second glue layer 6 on the first substrate 4 and gluing the second glue layer 6 to form the second glue layer 6 again.

after the permanent magnet template is used for multiple times, the flatness of the surface of the second glue layer 6 can not meet the use requirement any more, and the flattening treatment step can not be carried out any more. At this time, the second adhesive layer 6 can be peeled off, and the second adhesive layer 6 is formed again after the glue is applied and cured, so that the service life of the permanent magnet template is prolonged, and the cost is reduced.

The invention also provides a magnetic sensor prepared by the method.

Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.