Magnetic sensor preparation method and magnetic sensor

Abstract

The invention relates to a magnetic sensor preparation method and a magnetic sensor, after an inclined structure is manufactured on a substrate, a first TMR magnetic multilayer film pattern is formed on a plane / inclined structure of the substrate, and a second TMR magnetic multilayer film pattern is formed on the inclined structure / plane of the substrate. And etching the first TMR magnetic multilayer film pattern and the second TMR magnetic multilayer film pattern to form a first metal layer and magnetic tunnel junctions on the plane of the substrate and the inclined surface of the inclined structure, and performing metal coating and etching on the substrate to form a second metal layer connected with the magnetic tunnel junctions. By respectively forming the first TMR magnetic multilayer film pattern and the second TMR magnetic multilayer film pattern, the thickness of the generated TMR magnetic multilayer film can be controlled according to the actual deposition requirement of the plane / inclined structure of the substrate, so that the overall thickness of the TMR magnetic multilayer film is consistent or the thickness requirements of the plane and the inclined plane on the TMR magnetic multilayer film are respectively met; and the induction performance of the magnetic sensor is improved.

Description

Technical Field

[0001] The present application relates to the field of magnetic sensor technology, and in particular to a method for preparing a magnetic sensor and a magnetic sensor. Background Art

[0002] With the development of science and technology and the continuous progress of society, more and more types of magnetic sensors are appearing in people's daily work and life. TMR (Tunnel Magnetoresistance Effect) magnetic sensor is a magnetic sensor that utilizes the tunnel magnetoresistance effect, which includes a plurality of TMR magnetoresistance elements composed of magnetic tunnel junctions connected in series and / or in parallel. The external magnetic field can cause the resistance change of the TMR magnetoresistance element to realize the detection of the external magnetic field. However, TMR magnetoresistance elements can only sense the magnetic field in the plane. In order to enable the TMR magnetoresistance element to detect the out-of-plane magnetic field, one way is to set the magnetic tunnel junction on the slope. That is to say, in order to realize three-axis magnetic field detection, magnetic tunnel junctions are set on the plane and the slope, which are used for in-plane magnetic field sensing and out-of-plane magnetic field sensing respectively.

[0003] The traditional magnetic sensor preparation process is to deposit TMR magnetic films on planes and slopes, and then etch the TMR magnetic films to form magnetic tunnel junctions. The thickness of the TMR magnetic films on the planes and slopes is inconsistent or the thickness does not meet the usage requirements, resulting in poor sensing performance of the final magnetic sensor. Summary of the invention

[0004] Based on this, it is necessary to provide a method for preparing a magnetic sensor and a magnetic sensor that can improve the sensing performance of the magnetic sensor in order to address the above problems.

[0005] A method for preparing a magnetic sensor, comprising:

[0006] Making an inclined structure on the substrate;

[0007] Forming a first TMR magnetic multilayer thin film pattern on the plane / inclined structure of the substrate, and forming a second TMR magnetic multilayer thin film pattern on the inclined structure / plane of the substrate;

[0008] Etching the first TMR magnetic multilayer thin film pattern and the second TMR magnetic multilayer thin film pattern to form a first metal layer and a magnetic tunnel junction located on the plane of the substrate and the inclined surface of the inclined structure;

[0009] Metal coating and etching are performed on the substrate to form a second metal layer connecting the magnetic tunnel junctions.

[0010] In one embodiment, the first TMR magnetic multilayer film includes a structure for manufacturing a first metal layer, a magnetic tunnel junction and a cap layer, and / or the second TMR magnetic multilayer film includes a structure for manufacturing a first metal layer and a magnetic tunnel junction.

[0011] In one embodiment, the forming of the first TMR magnetic multilayer thin film pattern on the plane / inclined structure of the substrate, and the forming of the second TMR magnetic multilayer thin film pattern on the inclined structure / plane of the substrate respectively include:

[0012] forming a first TMR magnetic multilayer film on the substrate, etching the first TMR magnetic multilayer film, and retaining a portion of the planar / inclined structure on the substrate;

[0013] forming a second TMR magnetic multilayer film on the substrate, etching the second TMR magnetic multilayer film, and retaining a portion located on the inclined structure / plane of the substrate; the cap layer of the first TMR magnetic multilayer film is used for etching stop detection control when etching the second TMR magnetic multilayer film;

[0014] The first TMR magnetic multilayer film and the second TMR magnetic multilayer film retained on the substrate are etched to form a first TMR magnetic multilayer film pattern and a second TMR magnetic multilayer film pattern respectively.

[0015] In one embodiment, the forming of the first TMR magnetic multilayer thin film pattern on the plane / inclined structure of the substrate, and the forming of the second TMR magnetic multilayer thin film pattern on the inclined structure / plane of the substrate respectively include:

[0016] Forming a first TMR magnetic multilayer film on the substrate, etching the first TMR magnetic multilayer film to form a first TMR magnetic multilayer film pattern and a dummy pattern in a planar / inclined structure on the substrate;

[0017] A second TMR magnetic multilayer film is formed on the substrate, and the second TMR magnetic multilayer film is etched to form a second TMR magnetic multilayer film pattern located in an inclined structure / plane of the substrate; the cover layer of the first TMR magnetic multilayer film is used for etching stop detection control when etching the second TMR magnetic multilayer film.

[0018] In one embodiment, the first metal layer and the second metal layer are used to connect the magnetic tunnel junctions in series, in parallel, or in a combination of series and parallel to form a magnetic field sensitive region.

[0019] In one embodiment, the substrate comprises a stacked substrate and a first passivation layer; after metal plating and etching the substrate to form a second metal layer connecting the magnetic tunnel junctions, the method further comprises:

[0020] Depositing a second passivation layer on the second metal layer;

[0021] The second passivation layer is etched to obtain a top-layer connection hole exposing the second metal layer, and then metal deposition and etching are performed to obtain a top-layer metal layer.

[0022] In one embodiment, a portion of the top metal layer is used to form a coil, and a portion is used to connect to the second metal layer through the top connection hole; when the coil is powered on, each magnetic tunnel junction in the magnetic field sensitive area is reset.

[0023] In one embodiment, the second passivation layer is etched to obtain a top connection hole exposing the second metal layer, and then metal deposition and etching are performed to obtain a top metal layer. The method further comprises:

[0024] A third passivation layer is deposited on the top metal layer, and the third passivation layer is etched to form a conductive solder joint opening.

[0025] In one embodiment, the conductive solder joint opening is used to electrically connect the portion of the top metal layer connected to the second metal layer to an external device.

[0026] A magnetic sensor comprises a substrate, a first metal layer, a magnetic tunnel junction and a second metal layer, wherein the substrate comprises an inclined structure; and the magnetic sensor is prepared according to the above method.

[0027] The above-mentioned method for preparing a magnetic sensor and the magnetic sensor, after the substrate is made into an inclined structure, respectively forms a first TMR magnetic multilayer film pattern on the plane / inclined structure of the substrate, and forms a second TMR magnetic multilayer film pattern on the inclined structure / plane of the substrate. The first TMR magnetic multilayer film pattern and the second TMR magnetic multilayer film pattern are etched to form a first metal layer and a magnetic tunnel junction located on the plane of the substrate and the inclined surface of the inclined structure, and the substrate is metal plated and etched to form a second metal layer connecting each magnetic tunnel junction. By respectively forming the first TMR magnetic multilayer film pattern and the second TMR magnetic multilayer film pattern and then etching to obtain the first metal layer and the magnetic tunnel junction, the thickness of the generated TMR magnetic multilayer film can be controlled according to the actual deposition requirements at the plane / inclined structure of the substrate, ensuring that the overall thickness of the TMR magnetic multilayer film is consistent or meets the thickness requirements of the plane and the inclined surface for the TMR magnetic multilayer film, thereby improving the sensing performance of the magnetic sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a flow chart of a method for preparing a magnetic sensor in one embodiment;

[0029] Figure 2 A flow chart of forming a first TMR magnetic multilayer thin film pattern on a plane / inclined structure of a substrate and forming a second TMR magnetic multilayer thin film pattern on an inclined structure / plane of the substrate in one embodiment;

[0030] Figure 3-Figure 12 It is a structural schematic diagram of the preparation process of a substrate, a first TMR magnetic multilayer thin film pattern and a second TMR magnetic multilayer thin film pattern in one embodiment;

[0031] Fig.13 A flow chart of forming a first TMR magnetic multilayer thin film pattern on a plane / inclined structure of a substrate, and forming a second TMR magnetic multilayer thin film pattern on an inclined structure / plane of the substrate, respectively, in another embodiment;

[0032] Figure 14-Figure 20 It is a structural schematic diagram of a process for preparing a substrate, a first TMR magnetic multilayer thin film pattern, and a second TMR magnetic multilayer thin film pattern in another embodiment;

[0033] Fig.21 is a schematic structural diagram of a magnetic sensor in one embodiment;

[0034] Fig. 22 FIG. 1 is a flow chart of a method for preparing a magnetic sensor in one embodiment. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0037] It can be understood that the terms "first", "second", etc. used in the present application can be used in this article to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from another element.

[0038] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0039] In one embodiment, Figure 1 As shown, a method for preparing a magnetic sensor is provided, comprising:

[0040] Step S110: manufacturing an inclined structure on a substrate.

[0041] Among them, the substrate includes a substrate. The substrate may include a CMOS wafer layer and a CMOS signal layer arranged on the CMOS wafer layer. The CMOS wafer layer is integrated with an integrated circuit composed of several MOS tubes, which can process the analog signal generated by the external magnetic field induced by the magnetic field sensitive area to obtain a digital signal, and the CMOS signal layer can realize the functions of receiving analog signals and outputting digital signals. The CMOS signal layer can be in the form of a metal layer, an integrated circuit layer, etc., wherein the metal layer can be a copper layer, an aluminum layer, a copper alloy layer or an aluminum alloy layer. By making the magnetic sensor integrated with a substrate having a CMOS wafer layer and a CMOS signal layer, the magnetic sensor can be free of the need to integrate additional chips for signal processing, which is conducive to reducing the package size of the magnetic sensor. Further, the substrate may also include a protective layer arranged on the CMOS signal layer, which is used to protect the CMOS signal layer. The material of the protective layer can specifically be silicon oxide (SiOx) or aluminum oxide (AlOx).

[0042] The plane of the substrate and the inclined surface of the inclined structure are used to set the magnetic tunnel junction. The inclined structure can be a groove or a protrusion, and accordingly, the inclined surface of the inclined structure is the inclined surface of the groove or the inclined surface of the protrusion.

[0043] A magnetic tunnel junction generally includes a free layer / tunnel barrier layer / pinned layer. Changes in the external magnetic field will cause changes in the magnetization direction of the free layer. When the magnetization direction of the free layer is positively parallel to the pinning direction of the pinned layer, the magnetic tunnel junction is in a low resistance state; when the magnetization direction of the free layer is anti-parallel to the pinning direction of the pinned layer, the magnetic tunnel junction is in a high resistance state. It can be seen that the magnetic field component of the external magnetic field parallel to the pinning direction can cause a change in the magnetization direction of the free layer, and the parallel state with the pinning direction of the pinned layer can cause a change in the resistance of the magnetic tunnel junction. By connecting the magnetic tunnel junction in series, in parallel, or in a combination of series and parallel, an electrical signal corresponding to the component of the external magnetic field in the pinning direction can be output.

[0044] The substrate may further include a first passivation layer disposed on the substrate, and the inclined structure is disposed on the first passivation layer. The material of the first passivation layer may be silicon oxide (SiOx) or aluminum oxide (AlOx). A flat first passivation layer may be formed on the substrate first, and then a groove may be formed on the first passivation layer by etching; or a flat first passivation layer may be formed on the substrate first, and then a protrusion may be formed on the first passivation layer by etching, depositing, or mounting.

[0045] Step S120: forming a first TMR magnetic multilayer thin film pattern on the plane / inclined structure of the substrate, and forming a second TMR magnetic multilayer thin film pattern on the inclined structure / plane of the substrate.

[0046] Specifically, a first TMR magnetic multilayer thin film pattern may be formed on the plane of the substrate, and a second TMR magnetic multilayer thin film pattern may be formed on the inclined structure of the substrate; or a first TMR magnetic multilayer thin film pattern may be formed on the inclined structure of the substrate, and a second TMR magnetic multilayer thin film pattern may be formed on the plane of the substrate.

[0047] Specifically, a first TMR magnetic multilayer film may be first formed on the plane / inclined structure of the substrate, and then a second TMR magnetic multilayer film may be formed on the inclined structure / plane of the substrate, and finally the first TMR magnetic multilayer film and the second TMR magnetic multilayer film may be etched to obtain a first TMR magnetic multilayer film pattern and a second TMR magnetic multilayer film pattern, respectively; or a first TMR magnetic multilayer film may be first formed on the substrate, and then etching may be performed to obtain a first TMR magnetic multilayer film pattern located on the plane / inclined structure of the substrate, and then a second TMR magnetic multilayer film may be formed on the substrate, and then etching may be performed to obtain a second TMR magnetic multilayer film pattern located on the inclined structure / plane of the substrate.

[0048] Taking the example of first forming a first TMR magnetic multilayer film on the plane of the substrate, then forming a second TMR magnetic multilayer film on the inclined structure of the substrate, and finally etching the first TMR magnetic multilayer film and the second TMR magnetic multilayer film, the TMR coating is divided into two depositions according to the process requirements: the first deposition forms the first TMR magnetic multilayer film on the plane of the substrate according to the plane deposition requirements, and the second deposition forms the second TMR magnetic multilayer film on the inclined structure of the substrate according to the inclined surface deposition requirements. Factors such as the slope of the inclined structure can be analyzed to control the time of plane deposition and inclined surface deposition to ensure that the thickness difference between the first TMR magnetic multilayer film formed on the plane of the substrate and the second TMR magnetic multilayer film formed on the inclined structure of the substrate is within the allowable error range. Finally, by etching the first TMR magnetic multilayer film and the second TMR magnetic multilayer film, the first TMR magnetic multilayer film pattern located on the plane of the substrate and the second TMR magnetic multilayer film pattern located on the inclined structure of the substrate can be obtained.

[0049] It can be understood that in other embodiments, the first TMR magnetic multilayer film may be first formed on the inclined structure of the substrate, and then the second TMR magnetic multilayer film may be formed on the plane of the substrate. Finally, the first TMR magnetic multilayer film and the second TMR magnetic multilayer film may be etched to obtain corresponding thin film patterns.

[0050] Step S130: etching the first TMR magnetic multilayer thin film pattern and the second TMR magnetic multilayer thin film pattern to form a first metal layer and a magnetic tunnel junction located on the plane of the substrate and the inclined surface of the inclined structure.

[0051] Similarly, taking the example of first forming a first TMR magnetic multilayer film on the plane of the substrate, then forming a second TMR magnetic multilayer film on the inclined structure of the substrate, and then etching to generate a first TMR magnetic multilayer film pattern and a second TMR magnetic multilayer film pattern, after further etching the TMR magnetic multilayer film pattern, the first TMR magnetic multilayer film pattern is etched to obtain a first metal layer and a magnetic tunnel junction located on the plane of the substrate, and the second TMR magnetic multilayer film pattern is etched to obtain a first metal layer and a magnetic tunnel junction located on the inclined surface of the inclined structure. Wherein, the first TMR magnetic multilayer film and the second TMR magnetic multilayer film are both multilayer structures, the first TMR magnetic multilayer film may include a structure for making a first metal layer, a magnetic tunnel junction and a cap layer, and the second TMR magnetic multilayer film may include a structure for making a first metal layer and a magnetic tunnel junction. The cap layer of the first TMR magnetic multilayer film is used to perform etching stop detection control when etching the second TMR magnetic multilayer film, and the material of the cap layer may be tantalum ((Ta)) or other etching stop materials that do not affect the performance of the magnetic tunnel junction.

[0052] Step S140: performing metal coating and etching on the substrate to form a second metal layer connecting the magnetic tunnel junctions.

[0053] After the first metal layer and the magnetic tunnel junction are manufactured, the substrate is further metal plated and etched to form a second metal layer. The first metal layer and the second metal layer are used to connect the magnetic tunnel junctions in series, in parallel, or in combination of series and parallel to form a magnetic field sensitive area. Among them, the magnetic tunnel junction located on the plane of the substrate includes a magnetic tunnel junction with a pinning direction along the first direction and a magnetic tunnel junction with a pinning direction along the second direction. The magnetic tunnel junction with the pinning direction along the first direction is connected in series, in parallel, or in combination of series and parallel to form a magnetic field sensitive area to detect the magnetic field in the first direction. The magnetic tunnel junction with the pinning direction along the second direction is connected in series, in parallel, or in combination of series and parallel to form a magnetic field sensitive area to detect the magnetic field in the second direction. The magnetic tunnel junction located on the inclined surface of the inclined structure has a pinning direction along the inclined surface of the inclined structure. The magnetic field sensitive area is formed by connecting in series, in parallel, or in combination of series and parallel to detect the magnetic field in the third direction. Among them, the first direction and the second direction can be the X-axis direction and the Y-axis direction, respectively, or the Y-axis direction and the X-axis direction, respectively, and the third direction is the Z-axis direction.

[0054] The above-mentioned method for preparing a magnetic sensor, by respectively forming a first TMR magnetic multilayer film pattern and a second TMR magnetic multilayer film pattern, and then etching to obtain a first metal layer and a magnetic tunnel junction, can control the thickness of the generated TMR magnetic multilayer film according to the actual deposition requirements at the plane / inclined structure of the substrate, ensure that the overall thickness of the TMR magnetic multilayer film is consistent or meets the thickness requirements of the plane and inclined surface for the TMR magnetic multilayer film, thereby improving the sensing performance of the magnetic sensor.

[0055] In one embodiment, Figure 2 As shown, step S120 includes steps S121 to S123.

[0056] Step S121: forming a first TMR magnetic multilayer film on a substrate, etching the first TMR magnetic multilayer film, and retaining a portion of the planar / inclined structure located on the substrate.

[0057] Step S122: forming a second TMR magnetic multilayer film on the substrate, etching the second TMR magnetic multilayer film, and retaining the inclined structure / plane portion of the substrate; the cap layer of the first TMR magnetic multilayer film is used for etching stop detection control when etching the second TMR magnetic multilayer film.

[0058] Step S123: etching the first TMR magnetic multilayer film and the second TMR magnetic multilayer film retained on the substrate to form a first TMR magnetic multilayer film pattern and a second TMR magnetic multilayer film pattern, respectively.

[0059] In this embodiment, when the first etching and the second etching are performed, the required film layer area is retained, but the final pattern is not formed. When the plane and the inclined TMR magnetic multilayer films are both made, the third etching is performed to form the required film pattern. In this way, after the first etching, the area of ​​the first TMR magnetic multilayer film retained is relatively large, and accordingly, the area of ​​the cap layer of the first TMR magnetic multilayer film retained is also relatively large. During the second etching, the signal strength fed back by the cap layer is relatively strong, which is conducive to etching stop detection control when etching the second TMR magnetic multilayer film.

[0060] Specifically, Figure 3 As shown, the substrate 110 includes a substrate 112 and a first passivation layer 114, and the substrate 112 includes a CMOS wafer layer 1122, a CMOS signal layer 1124 and a protective layer 1126 which are stacked in sequence. The first passivation layer 114 can be a silicon oxide layer, and the first passivation layer 114 can be formed on the substrate 112 by coating, physical vapor deposition (PVD), chemical vapor deposition (CVD), etc. The first passivation layer 114 is etched to form a groove, and the etching stops at the CMOS signal layer 1124. Then, a thin film is re-deposited on the substrate 110 to cover the CMOS signal layer 1124 exposed in the groove. The material of the thin film can be one or both of silicon oxide and silicon nitride. The groove is formed as an inclined structure on the substrate 110.

[0061] Similarly, for example, a first TMR magnetic multilayer film is first formed on the plane of the substrate 110, and then a second TMR magnetic multilayer film is formed on the inclined structure of the substrate 110. Figure 3 As shown, first, a first TMR magnetic multilayer film 120a is deposited on the first passivation layer 114, and the first TMR magnetic multilayer film 120a covers the plane and groove parts of the substrate 110. The first TMR magnetic multilayer film 120a includes a structure for making a first metal layer, a magnetic tunnel junction and a cap layer, and the first TMR magnetic multilayer film 120a can be formed by physical vapor deposition. Figure 4 As shown, a stripping glue is applied to the position where the first TMR magnetic multilayer film 120a is to be retained on the substrate 110 and photolithography is performed, and the etching stops at the first passivation layer 114 and the film at the bottom of the groove, so as to obtain the first TMR magnetic multilayer film 120a located on the plane of the substrate, as shown in FIG. Figure 5 As shown, then remove the stripping adhesive, as Figure 6 shown.

[0062] like Figure 7As shown, a second TMR magnetic multilayer film 120b is deposited on the substrate 110, and the second TMR magnetic multilayer film 120b covers the plane and groove portions of the substrate 110, and covers the retained first TMR magnetic multilayer film 120a. The second TMR magnetic multilayer film 120b includes a structure for making a first metal layer and a magnetic tunnel junction, and the second TMR magnetic multilayer film 120b can be formed by physical vapor deposition. Figure 8 As shown, a stripping glue is applied to the position where the second TMR magnetic multilayer film 120b is to be retained on the substrate 110 and photolithography is performed, and part of the etching stops at the first passivation layer 114, and part of the etching stops at the cap layer of the first TMR magnetic multilayer film 120a, so as to obtain the second TMR magnetic multilayer film 120b located in the groove of the substrate 110, as shown in FIG. Fig. 9 As shown, then remove the stripping adhesive, as Fig.10 shown.

[0063] like Fig.11 As shown, a stripping glue is applied to the substrate 110, and the first TMR magnetic multilayer film 120a and the second TMR magnetic multilayer film 120b retained on the substrate 110 are pattern-etched to the first passivation layer 114 to form a first TMR magnetic multilayer film pattern 120c and a second TMR magnetic multilayer film pattern 120d, respectively, and then the stripping glue is removed, as shown in FIG. Fig.12 The second TMR magnetic multilayer film 120b on at least one groove is etched away to form a connection groove (not shown in the drawings), and a connection hole is etched along the thickness direction at the bottom of the connection groove of the substrate 110 to expose the CMOS signal layer 1124 for subsequent connection of the second metal layer with the CMOS signal layer 1124.

[0064] In one embodiment, Fig.13 As shown, step S120 includes steps S124 to S125.

[0065] Step S124: forming a first TMR magnetic multilayer film on the substrate, and etching the first TMR magnetic multilayer film to form a first TMR magnetic multilayer film pattern and a dummy pattern in a planar / inclined structure on the substrate.

[0066] Step S125: forming a second TMR magnetic multilayer film on the substrate, and etching the second TMR magnetic multilayer film to form a second TMR magnetic multilayer film pattern located on an inclined structure / plane of the substrate; the cap layer of the first TMR magnetic multilayer film is used as an etching stop detection control when etching the second TMR magnetic multilayer film.

[0067] In this embodiment, when the first etching and the second etching are performed, the required thin film pattern is directly formed, thereby reducing the number of etching times. After the first TMR magnetic multilayer film is patterned and etched, the cap layer area in the formed first TMR magnetic multilayer film pattern becomes smaller, and the signal strength of its feedback will be very weak. Therefore, when the first TMR magnetic multilayer film is etched to form a thin film pattern during the first etching, a portion of the first TMR magnetic multilayer film is retained as a dummy pattern to improve the signal capture quality. When the second TMR magnetic multilayer film covering the first TMR magnetic multilayer film is etched and controlled, the signal strength of the cap layer feedback can be enhanced, thereby improving the etching control accuracy of the second TMR magnetic multilayer film.

[0068] Similarly, for example, a first TMR magnetic multilayer film is first formed on the plane of the substrate 110, and then a second TMR magnetic multilayer film is formed on the inclined structure of the substrate. Fig.14 As shown, a first TMR magnetic multilayer film 120a is deposited on the first passivation layer 114. The first TMR magnetic multilayer film 120a covers the plane and the groove portion of the substrate 110. The first TMR magnetic multilayer film 120a includes a structure for making a first metal layer, a magnetic tunnel junction and a cap layer. A stripping adhesive is applied to the position of the substrate 110 where the first TMR magnetic multilayer film 120a needs to be retained, and photolithography is performed. The etching stops at the first passivation layer 114 and the film at the bottom of the groove, and the first TMR magnetic multilayer film pattern 120c and the dummy pattern located on the plane of the substrate are obtained, as shown in FIG. Fig.15 As shown (the pseudo pattern is not shown in the drawings), the stripping glue is then removed, as shown in FIG. Fig.16 shown.

[0069] like Fig.17 As shown, a second TMR magnetic multilayer film 120b is deposited on the substrate 110, and the second TMR magnetic multilayer film 120b covers the plane and groove portions of the substrate 110, and covers the retained first TMR magnetic multilayer film pattern 120c and the dummy pattern, and the second TMR magnetic multilayer film 120b includes a structure for making a first metal layer and a magnetic tunnel junction. Fig.18 As shown, a stripping glue is applied to the position where the second TMR magnetic multilayer film 120b is to be retained on the substrate 110 and photolithography is performed, and part of the etching stops at the first passivation layer 114 and the film at the bottom of the groove, and part of the etching stops at the first TMR magnetic multilayer film pattern 120c and the cover layer of the dummy pattern, so as to obtain the second TMR magnetic multilayer film pattern 120d located in the groove of the substrate 110, as shown in FIG. Fig.19 As shown, then remove the stripping adhesive, as Fig. 20Similarly, the second TMR magnetic multilayer film 120b on at least one groove is etched away to form a connection groove (not shown in the drawings), and a connection hole is etched along the thickness direction at the bottom of the connection groove of the substrate 110 to expose the CMOS signal layer 1124 for subsequent connection of the second metal layer with the CMOS signal layer 1124.

[0070] It should be noted that the above two embodiments are both described by taking the example of first forming the first TMR magnetic multilayer film 120a on the plane of the substrate 110 and then forming the second TMR magnetic multilayer film 120b on the inclined structure of the substrate 110. It is necessary to etch away the first TMR magnetic multilayer film 120a on the inclined structure and then deposit the second TMR magnetic multilayer film 120b on the inclined structure. In the process of removing the film on the inclined surface of the inclined structure, the roughness of the inclined surface is greatly affected, thereby having a greater impact on the roughness of the second TMR magnetic multilayer film 120b formed by the second deposition. In other embodiments, the first TMR magnetic multilayer film 120a may be formed on the substrate 110 first, the first TMR magnetic multilayer film 120a on the inclined structure is retained, and the first TMR magnetic multilayer film 120a on the plane of the substrate 110 is removed. Relatively speaking, the removal of the first TMR magnetic multilayer film 120a on the plane of the substrate 110 has a smaller impact on the roughness of the plane of the substrate 110, and then the second TMR magnetic multilayer film 120b on the plane is formed by a second deposition, which can avoid affecting the roughness of the first TMR magnetic multilayer film 120a on the inclined structure. In other words, the deposition order of the TMR magnetic multilayer films on the plane and the inclined structure can be dynamically adjusted according to specific roughness requirements.

[0071] like Fig.21 As shown, in step S130, the first TMR magnetic multilayer film pattern 120c and the second TMR magnetic multilayer film pattern 120d are etched to form the first metal layer 120 and the magnetic tunnel junction 130 located on the plane of the substrate 110 and the inclined surface of the inclined structure, and then in step S140, metal plating and etching are performed on the substrate 110 to form the second metal layer 140 connecting each magnetic tunnel junction 130. Specifically, the second metal layer 140 connects each magnetic tunnel junction 130 and extends to the CMOS signal layer 1124 of the substrate 110 through the connection hole at the bottom of the connection groove, so that the magnetic tunnel junction 130 and the substrate 110 are electrically connected through the second metal layer 140, so as to receive the output signal of the bridge composed of the magnetic tunnel junction 130 and feed it back to the substrate 110.

[0072] In one embodiment, Fig. 22 As shown, after step S140, the method further includes step S150 and step S160.

[0073] Step S150: depositing a second passivation layer on the second metal layer.

[0074] Specifically, Fig.21 As shown, a second passivation layer 150 is deposited on the second metal layer 140 to cover the second metal layer 140 and the exposed first passivation layer 114 . The second passivation layer 150 may be made of aluminum oxide or silicon oxide.

[0075] Step S160: etching the second passivation layer to obtain a top-layer connection hole exposing the second metal layer, and then performing metal deposition and etching to obtain a top-layer metal layer.

[0076] Continue to refer to Fig.21 After etching the second passivation layer 150 to obtain a top connection hole (not shown in the drawings) exposing the second metal layer 140, metal deposition and etching are performed to obtain a top metal layer 160. A portion of the top metal layer 160 is used to form a coil to reset each magnetic tunnel junction in the magnetic field sensitive area when power is turned on, and a portion is used to connect to the second metal layer 140 through the top connection hole.

[0077] In addition, if Fig. 22 As shown, after step S160, the method further includes step S170: depositing a third passivation layer on the top metal layer, and etching the third passivation layer to form a conductive solder joint opening.

[0078] like Fig.21 As shown, a third passivation layer 170 is deposited on the top metal layer 160, and the third passivation layer 170 covers the top metal layer 160 and may also cover the exposed second passivation layer 150. Then, a conductive solder joint opening (not shown in the drawings) is formed in the third passivation layer 170, which protects the top metal layer 160 and allows the top metal layer 160 to be electrically connected to a portion of the second metal layer 140 and an external device through the conductive solder joint opening. The third passivation layer 170 may also be aluminum oxide or silicon oxide.

[0079] In one embodiment, a magnetic sensor is provided, comprising a substrate, a first metal layer, a magnetic tunnel junction and a second metal layer, wherein the substrate comprises an inclined structure. Further, the magnetic sensor may also comprise a second passivation layer, a top metal layer and a third passivation layer. The magnetic sensor is prepared according to the above method.

[0080] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0081] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A method for preparing a magnetic sensor, characterized in that: include: Making an inclined structure on the substrate; Forming a first TMR magnetic multilayer thin film pattern on the plane / inclined structure of the substrate, and forming a second TMR magnetic multilayer thin film pattern on the inclined structure / plane of the substrate; Etching the first TMR magnetic multilayer thin film pattern and the second TMR magnetic multilayer thin film pattern to form a first metal layer and a magnetic tunnel junction located on the plane of the substrate and the inclined surface of the inclined structure; Metal coating and etching are performed on the substrate to form a second metal layer connecting the magnetic tunnel junctions.

2. The method according to claim 1, characterized in that The first TMR magnetic multilayer film includes a structure for manufacturing a first metal layer, a magnetic tunnel junction and a cap layer, and / or the second TMR magnetic multilayer film includes a structure for manufacturing a first metal layer and a magnetic tunnel junction.

3. The method according to claim 2, characterized in that The method of forming a first TMR magnetic multilayer film pattern on the plane / inclined structure of the substrate, and forming a second TMR magnetic multilayer film pattern on the inclined structure / plane of the substrate, comprises: forming a first TMR magnetic multilayer film on the substrate, etching the first TMR magnetic multilayer film, and retaining a portion of the planar / inclined structure on the substrate; forming a second TMR magnetic multilayer film on the substrate, etching the second TMR magnetic multilayer film, and retaining a portion located on the inclined structure / plane of the substrate; the cap layer of the first TMR magnetic multilayer film is used for etching stop detection control when etching the second TMR magnetic multilayer film; The first TMR magnetic multilayer film and the second TMR magnetic multilayer film retained on the substrate are etched to form a first TMR magnetic multilayer film pattern and a second TMR magnetic multilayer film pattern respectively.

4. The method according to claim 2, characterized in that: The method of forming a first TMR magnetic multilayer film pattern on the plane / inclined structure of the substrate, and forming a second TMR magnetic multilayer film pattern on the inclined structure / plane of the substrate, comprises: Forming a first TMR magnetic multilayer film on the substrate, etching the first TMR magnetic multilayer film to form a first TMR magnetic multilayer film pattern and a dummy pattern in a planar / inclined structure on the substrate; A second TMR magnetic multilayer film is formed on the substrate, and the second TMR magnetic multilayer film is etched to form a second TMR magnetic multilayer film pattern located in an inclined structure / plane of the substrate; the cover layer of the first TMR magnetic multilayer film is used for etching stop detection control when etching the second TMR magnetic multilayer film.

5. The method according to any one of claims 1 to 4, characterized in that: The first metal layer and the second metal layer are used to connect the magnetic tunnel junctions in series, in parallel, or in a combination of series and parallel to form a magnetic field sensitive region.

6. The method according to claim 5, characterized in that The substrate comprises a stacked substrate and a first passivation layer; after the substrate is subjected to metal plating and etching to form a second metal layer connecting the magnetic tunnel junctions, the method further comprises: Depositing a second passivation layer on the second metal layer; The second passivation layer is etched to obtain a top-layer connection hole exposing the second metal layer, and then metal deposition and etching are performed to obtain a top-layer metal layer.

7. The method according to claim 6, characterized in that A portion of the top metal layer is used to form a coil, and a portion of the top metal layer is used to connect to the second metal layer through the top connection hole; when the coil is powered on, each magnetic tunnel junction in the magnetic field sensitive area is reset.

8. The method according to claim 6, characterized in that The second passivation layer is etched to obtain a top-layer connection hole exposing the second metal layer, and then metal deposition and etching are performed to obtain a top-layer metal layer, and the method further includes: A third passivation layer is deposited on the top metal layer, and the third passivation layer is etched to form a conductive solder joint opening.

9. The method according to claim 8, characterized in that The conductive solder joint opening is used to electrically connect the portion of the top metal layer connected to the second metal layer to an external device.

10. A magnetic sensor, characterized in that: The invention comprises a substrate, a first metal layer, a magnetic tunnel junction and a second metal layer, wherein the substrate comprises an inclined structure; and the magnetic sensor is prepared according to the method described in any one of claims 1 to 9.

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