Magnetic sensor

Abstract

This suppresses problems caused by the conductive layer connected to the magnetoresistive element. [Solution] The magnetic sensor 1 comprises an MR element 50 including a magnetization fixed layer 51, a free layer 53, and a gap layer 52, a protective layer 70 disposed on the MR element 50, and a conductive layer 422 electrically connected to the MR element 50. The protective layer 70 includes a first portion 60 and a second portion 421A sandwiching the first portion 60 between itself and the MR element 50. When viewed from the stacking direction of the magnetization fixed layer 51, the gap layer 52, and the free layer 53, the outer edge 472Ae of the second portion 421A is inside the outer edge 60e of the first portion 60. The conductive layer 422 is in contact with the second portion 421A.

Description

Technical Field

[0001] The present disclosure relates to a magnetic sensor including a magnetoresistive element and a protective layer disposed on the magnetoresistive element.

Background Art

[0002] In recent years, magnetic sensors have been used in various applications. As a magnetic sensor, one using a spin valve type magnetoresistive element provided on a substrate is known. The spin valve type magnetoresistive element has a magnetization fixed layer having a magnetization with a fixed direction, a free layer having a magnetization whose direction can change according to the direction of a target magnetic field, and a gap layer disposed between the magnetization fixed layer and the free layer.

[0003] Patent Document 1 discloses a magnetic sensor device having a plurality of TMR (tunnel magnetoresistance) elements. The TMR element has a free layer having a disk-shaped structure. In the free layer, a magnetization pattern having a closed magnetic flux, also called a vortex state, is spontaneously formed. In a magnetoresistive element including a free layer having a magnetic vortex structure as described in Patent Document 1, the center of the magnetic vortex structure moves according to the magnetic field to be detected, and thereby the resistance value of the magnetoresistive element changes.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a TMR element, a lower electrode and an upper electrode are connected to the lower and upper surfaces of the TMR element, respectively, in order to flow the sense current for detecting magnetic signals in a direction approximately perpendicular to the surface of each layer constituting the TMR element. The upper electrode is formed, for example, as follows: First, an insulating layer is formed to cover the TMR element. Next, an opening is formed in the insulating layer to expose the upper surface of the TMR element. Then, a conductive layer is formed to fill the opening, constituting at least a part of the upper electrode.

[0006] After forming an opening in the insulating layer, ion beam etching or reverse sputtering may be performed on a portion of the upper surface of the TMR element. In this case, depending on the conditions of ion beam etching or reverse sputtering, the free layer of the TMR element may be damaged. In particular, the effect of damage is significantly apparent in free layers having a magnetic vortex structure as described in Patent Document 1.

[0007] This disclosure has been made in view of the aforementioned problems, and its purpose is to provide a magnetic sensor that can suppress the occurrence of problems caused by a conductive layer connected to a magnetoresistive element. [Means for solving the problem]

[0008] The magnetic sensor of this disclosure comprises a magnetoresistive element including a magnetization-fixed layer having a magnetization with a fixed direction, a free layer having a magnetization that can change in response to an applied magnetic field, and a gap layer disposed between the magnetization-fixed layer and the free layer; a protective layer disposed on the magnetoresistive element; and a conductive layer electrically connected to the magnetoresistive element. The protective layer includes a first portion and a second portion sandwiching the first portion between itself and the magnetoresistive element. When viewed in the stacking direction of the magnetization-fixed layer, the gap layer, and the free layer, the outer edge of the second portion lies inside the outer edge of the first portion. The conductive layer is in contact with the second portion. [Effects of the Invention]

[0009] In the magnetic sensor of this disclosure, when viewed from the stacking direction of the magnetized fixed layer, gap layer, and free layer, the outer edge of the second portion lies inside the outer edge of the first portion. The conductive layer is in contact with the second portion. This has the effect of suppressing the occurrence of problems caused by the conductive layer, according to this disclosure. [Brief explanation of the drawing]

[0010] [Figure 1] This is a plan view showing a magnetic sensor according to the first embodiment of the present disclosure. [Figure 2] This is a circuit diagram showing the circuit configuration of a magnetic sensor according to the first embodiment of this disclosure. [Figure 3] This is a plan view showing a part of a magnetic sensor according to the first embodiment of the present disclosure. [Figure 4] This is a cross-sectional view showing a part of the magnetic sensor according to the first embodiment of this disclosure. [Figure 5] This is a cross-sectional view showing a magnified portion of the magnetic sensor shown in Figure 4. [Figure 6] This is a plan view showing the protective layer in the first embodiment of the present disclosure. [Figure 7] This is a perspective view showing a magnetoresistive element in the first embodiment of the present disclosure. [Figure 8] This is a plan view showing the free layer of a magnetoresistive element in the first embodiment of the present disclosure. [Figure 9] This is a plan view showing the free layer of a magnetoresistive element in the first embodiment of this disclosure when a target magnetic field is applied to it. [Figure 10] This is a plan view showing the free layer of a magnetoresistive element in the first embodiment of this disclosure when a target magnetic field is applied to it. [Figure 11] This is a cross-sectional view showing one step in a method for manufacturing a magnetic sensor according to the first embodiment of the present disclosure. [Figure 12] This is a cross-sectional view showing the process following the process shown in Figure 11. [Figure 13] This is a cross-sectional view showing the process following the process shown in Figure 12. [Figure 14] It is a cross-sectional view showing a process following the process shown in FIG. 13. [[ID [Figure 15] It is a cross-sectional view showing a process following the process shown in FIG. 14. [Figure 16] It is a cross-sectional view showing a part of a modified example of the magnetic sensor according to the first embodiment of the present disclosure. [Figure 17] It is a cross-sectional view showing a process in the method for manufacturing a magnetic sensor according to the second embodiment of the present disclosure. [Figure 18] It is a cross-sectional view showing a process following the process shown in FIG. 17. [Figure 19] It is a cross-sectional view showing a process following the process shown in FIG. 18. [Figure 20] It is an enlarged cross-sectional view showing a part of the magnetic sensor according to the third embodiment of the present disclosure. [Figure 21] It is an enlarged cross-sectional view showing a part of the magnetic sensor according to the fourth embodiment of the present disclosure.

MODE FOR CARRYING OUT THE INVENTION

[0011] [First Embodiment] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. First, referring to FIGS. 1 and 2, a schematic configuration of a magnetic sensor according to the first embodiment of the present disclosure will be described. FIG. 1 is a plan view showing a magnetic sensor 1 according to the present embodiment. FIG. 2 is a circuit diagram showing a circuit configuration of the magnetic sensor 1 according to the present embodiment.

[0012] The magnetic sensor 1 according to the present embodiment includes a power supply terminal 11, a ground terminal 12, a first output terminal 13, a second output terminal 14, a first resistance portion R1, a second resistance portion R2, a third resistance portion R3, a fourth resistance portion R4, and a substrate 10. Each of the first to fourth resistance portions R1 to R4 includes a plurality of magnetoresistive effect elements (hereinafter referred to as MR elements). The first to fourth resistance portions R1 to R4, the power supply terminal 11, the ground terminal 12, and the first and second output terminals 13 and 14 are provided on the substrate 10.

[0013] As shown in Figure 2, the first resistor R1 is located between the power supply terminal 11 and the first output terminal 13 in the circuit configuration. The second resistor R2 is located between the ground terminal 12 and the first output terminal 13 in the circuit configuration. The third resistor R3 is located between the ground terminal 12 and the second output terminal 14 in the circuit configuration. The fourth resistor R4 is located between the power supply terminal 11 and the second output terminal 14 in the circuit configuration. In this application, the expression "in the circuit configuration" refers to the arrangement on the circuit diagram, not the arrangement in the physical configuration.

[0014] A predetermined voltage or current is applied to the power terminal 11. The ground terminal 12 is connected to ground.

[0015] Here, as shown in Figure 1, we define the X, Y, and Z directions. The X, Y, and Z directions are orthogonal to each other. Furthermore, the direction opposite to the X direction is defined as the -X direction, the direction opposite to the Y direction is defined as the -Y direction, and the direction opposite to the Z direction is defined as the -Z direction. In this embodiment, in particular, the direction perpendicular to the surface of the substrate 10 is defined as the Z direction.

[0016] Furthermore, below, a position located at the end of the Z-direction relative to a certain reference position will be referred to as "above," and a position opposite to "above" relative to a certain reference position will be referred to as "below." Also, with respect to the components of magnetic sensor 1, the surface located at the end in the Z-direction will be referred to as the "top surface," and the surface located at the end in the -Z-direction will be referred to as the "bottom surface." In addition, the expression "when viewed from a predetermined direction (for example, the Z-direction)" means viewing the object from a position at a distance in a predetermined direction or a direction parallel to the predetermined direction.

[0017] Figure 1 shows an example of the arrangement of the first to fourth resistors R1 to R4. In this example, the first and second resistors R1 and R2 are aligned parallel to the X direction. The second resistor R2 is positioned ahead of the first resistor R1 in the X direction.

[0018] The third and fourth resistors R3 and R4 are aligned parallel to the X direction. The fourth resistor R4 is positioned ahead of the third resistor R3 in the -X direction. The third resistor R3 is positioned ahead of the second resistor R2 in the -Y direction. The fourth resistor R4 is positioned ahead of the first resistor R1 in the -Y direction.

[0019] Note that the arrangement of the first to fourth resistors R1 to R4 is not limited to the example shown in Figure 1. For example, the first to fourth resistors R1 to R4 may be arranged in a predetermined order in a direction parallel to the X direction or parallel to the Y direction.

[0020] Next, the specific structure of the magnetic sensor 1 will be described in detail with reference to Figures 3 and 4. Figure 3 is a plan view showing a part of the magnetic sensor 1. Figure 4 is a cross-sectional view showing a part of the magnetic sensor 1.

[0021] The magnetic sensor 1 in this embodiment comprises a plurality of MR elements 50, and a plurality of lower electrodes 41 and a plurality of upper electrodes 42 for electrically connecting the plurality of MR elements 50. The plurality of lower electrodes 41 are arranged on a substrate 10 (see Figure 1). The plurality of MR elements 50 are arranged on the plurality of lower electrodes 41. The plurality of upper electrodes 42 are arranged on the plurality of MR elements 50.

[0022] The method for connecting the multiple MR elements 50 with the multiple lower electrodes 41 and the multiple upper electrodes 42 is as follows. As shown in Figure 3, each lower electrode 41 has an elongated shape. A gap is formed between two adjacent lower electrodes 41 in the longitudinal direction. On the upper surface of the lower electrode 41, an MR element 50 is placed near both ends in the longitudinal direction. Each upper electrode 42 also has an elongated shape and is placed on two adjacent lower electrodes 41 in the longitudinal direction to electrically connect two adjacent MR elements 50. In this way, multiple MR elements 50 are connected in series.

[0023] The upper electrode 42 includes a base layer 421 and a conductive layer 422 placed on top of the base layer 421. The base layer 421 is in contact with the upper surface of the MR element 50. For example, Ta, Ti, etc. can be used as the material for the base layer 421. For example, Cu, Au, Al, etc. can be used as the material for the conductive layer 422.

[0024] The magnetic sensor 1 further comprises a protective layer 70 placed on the MR element 50, an inorganic material layer 80 placed on the protective layer 70, and an insulating layer 30. The insulating layer 30 is placed around the lower electrode 41, around the MR element 50, around the protective layer 70, around the inorganic material layer 80, and around the upper electrode 42. The insulating layer 30 may be a single layer or a multilayer film. In the latter case, the multilayer film may be composed of one insulating material or of multiple insulating materials.

[0025] For example, carbon, Al2O3, etc., can be used as the material for the inorganic material layer 80. For example, SiO2, Al2O3, etc., can be used as the material for the insulating layer 30.

[0026] Next, the structures of the protective layer 70 and the inorganic material layer 80 will be described in detail with reference to Figures 5 and 6. Figure 5 is an enlarged cross-sectional view showing a portion of the magnetic sensor 1 shown in Figure 4. Figure 6 is a plan view showing the protective layer 70 in this embodiment. The protective layer 70 includes a first portion 60 placed on the MR element 50 and a second portion 421A sandwiching the first portion 60 between the MR element 50 and the protective layer 70.

[0027] In this embodiment, the second portion 421A is also part of the underlayer 421. That is, the underlayer 421 includes the second portion 421A and the portion 421B other than the second portion 421A. In Figure 5, the boundary between the second portion 421A and portion 421B is shown by a dashed line. In the diagrams similar to Figure 5 used in the following explanation, the boundary between the second portion 421A and portion 421B is also shown by a dashed line.

[0028] The first portion 60 includes a first metal film made of a first metallic material. The first portion 60 may be a single layer film made of the first metal film, or a multilayer film including the first metal film. The second portion 421A may include a second metal film made of the first metallic material. The second portion 421A may be a single layer film made of the second metal film, or a multilayer film including the second metal film. If at least one of the first portion 60 and the second portion 421A is a multilayer film including the first metal film, the protective layer 70 may further include a third metal film made of a second metallic material. The third metal film may be positioned between the first metal film and the second metal film.

[0029] The first metallic material may be, for example, Ta. If the first portion 60 is a multilayer film, the first portion 60 may include, in addition to the first metallic film made of Ta, at least one metallic film as a third metallic film, for example, made of a Ni-based nonmagnetic alloy metallic material such as Ru, Ta, Cu, Cr, or NiCr. Also, if the second portion 421A is a multilayer film, the second portion 421A may include, in addition to the second metallic film made of Ta, at least one metallic film as a third metallic film, for example, made of a metallic material such as Ti. In one example, the first portion 60 is a multilayer film in which a metallic film made of Ru and a metallic film made of Ta are laminated, and the second portion 421A is a multilayer film in which a metallic film made of Ti and a metallic film made of Ta are laminated.

[0030] As shown in Figure 5, the first portion 60 of the protective layer 70 has a first surface 60a and a second surface 60b located at both ends in a direction parallel to the Z direction. The first surface 60a faces the MR element 50. The second surface 60b faces the second portion 421A. The second surface 60b may be entirely parallel to the first surface 60a, or a portion of it may be parallel to the first surface 60a.

[0031] As shown in Figure 6, the planar shape (shape viewed from the Z direction) of the second portion 421A is smaller than the planar shape of the first portion 60. In Figure 6, the numeral 60e indicates the outer edge of the first portion 60 when viewed from the Z direction, and the numeral 421Ae indicates the outer edge of the second portion 421A when viewed from the Z direction. When viewed from the Z direction, the outer edge 421Ae of the second portion 421A lies inside the outer edge 60e of the first portion 60.

[0032] Note that the outer edge 60e shown in Figure 6 may be the outer edge of the second surface 60b of the first portion 60. That is, when viewed from the Z direction, the outer edge 421Ae of the second portion 421A may be inside the outer edge of the second surface 60b of the first portion 60.

[0033] Figure 6 shows an example where the planar shape of the first portion 60 and the planar shape of the second portion 421A are both circular. In this case, it is preferable that the second portion 421A is positioned so as to coincide with the center of the planar shape of the first portion 60 when viewed from the Z direction, and it is more preferable that the center of the planar shape of the first portion 60 and the center of the planar shape of the second portion 421A coincide.

[0034] The first portion 60 further has a side surface 60d connecting the first surface 60a and the second surface 60b. At least a portion of the side surface 60d may be inclined with respect to a direction parallel to the Z direction (the stacking direction). Also, the area of ​​the cross-section of the first portion 60 parallel to the XY plane may decrease as it approaches the second surface 60b. When viewed from the Z direction, the outer edge of the second surface 60b may be inside the outer edge of the first surface 60a.

[0035] The inorganic material layer 80 is positioned on the first portion 60 of the protective layer 70, around the second portion 421A. When viewed from the Z direction, the planar outer edge of the inorganic material layer 80 may coincide with the outer edge 60e of the first portion 60 or the outer edge of the second surface 60b.

[0036] Furthermore, the outer diameter of the planar shape of the inorganic material layer 80 may be less than or equal to the outer diameter of the planar shape of the MR element 50. Also, the area of ​​the cross-section of the inorganic material layer 80 parallel to the XY plane may be constant regardless of the distance from the second surface 60b, or it may decrease as it moves away from the second surface 60b. In the latter case, the inorganic material layer 80 may have a side surface that connects the lower surface and the upper surface of the inorganic material layer 80 and is inclined with respect to the direction parallel to the Z direction (stacking direction). In this case, the outer edge of the upper surface of the inorganic material layer 80 is inside the outer edge of the planar shape of the MR element 50 when viewed from the Z direction.

[0037] The inorganic material layer 80 has an opening 80a that exposes a portion of the second surface 60b of the first portion 60 of the protective layer 70. The size of the opening 80a in the cross-section of the inorganic material layer 80 parallel to the XY plane may be constant regardless of the distance from the second surface 60b, or it may increase as it moves away from the second surface 60b.

[0038] The insulating layer 30 may cover the upper surface of the inorganic material layer 80. In this case, the insulating layer 30 has an opening that exposes the opening 80a of the inorganic material layer 80.

[0039] The underlayer 421, including the second portion 421A, is positioned along the wall surface of the opening 80a and a portion of the second surface 60b of the inorganic material layer 80. If the insulating layer 30 covers the upper surface of the inorganic material layer 80, the underlayer 421 is further positioned along the surface of the insulating layer 30, including the wall surface of the opening of the insulating layer 30.

[0040] The second portion 421A is in direct contact with the first portion 60 and also in contact with the wall surface of the opening 80a of the inorganic material layer 80. Since the second portion 421A is a component of the upper electrode 42, it can also be said that the upper electrode 42 is in contact with the first portion 60. Note that portion 421B of the base layer 421 is in contact with the wall surface of the opening 80a of the inorganic material layer 80, but not with the first portion 60.

[0041] Next, the configuration of the MR element 50 will be described with reference to Figures 7 and 8. Figure 7 is a perspective view showing the MR element 50. Figure 8 is a plan view showing the free layer of the MR element 50.

[0042] The MR element 50 includes a magnetization-fixed layer 51 having a magnetization 51m with a fixed direction, a free layer 53, and a gap layer 52 disposed between the magnetization-fixed layer 51 and the free layer 53. The material and shape of the free layer 53 are selected so that it may have a magnetic vortex structure (also called a vortex structure). The gap layer 52 is a tunnel barrier layer or a non-magnetic conductive layer.

[0043] The free layer 53 has a cylindrical or nearly cylindrical shape. The free layer 53 also has a magnetization 53m that is swirled around the center 53c of the magnetic vortex structure. When no magnetic field is applied to the MR element 50, the center 53c of the magnetic vortex structure coincides with or nearly coincides with the axis of the cylinder. The free layer 53 is configured so that the center 53c of the magnetic vortex structure can move in response to the target magnetic field MF. In the examples shown in Figures 7 and 8, the entire MR element 50 has a cylindrical shape.

[0044] The center 53c of the magnetic vortex structure moves when a component of the target magnetic field MF perpendicular to the Z direction is applied to the free layer 53. Within the range of change in the intensity of this component, it is preferable that the free layer 53 does not saturate.

[0045] Here, the dimension in the direction parallel to the Z direction is called thickness. The thickness of the first portion 60 of the protective layer 70 may be set based on the thickness of the free layer 53. In this embodiment in particular, the thickness of the first portion 60 may be in the range of 40 to 100% of the thickness of the free layer 53. Alternatively, the thickness of the first portion 60 may be in the range of 20 to 40% of the thickness of the free layer 53.

[0046] In this embodiment, the magnetization 51m of the magnetized fixed layer 51 includes a component in a direction parallel to the X direction. If the magnetization 51m of the magnetized fixed layer 51 includes a component in a specific direction, that component may be the main component of the magnetization 51m of the magnetized fixed layer 51. In this embodiment, if the magnetization 51m of the magnetized fixed layer 51 includes a component in a specific direction, the direction of the magnetization 51m of the magnetized fixed layer 51 will be a specific direction or approximately a specific direction.

[0047] The MR element 50 may further include an antiferromagnetic layer. The antiferromagnetic layer is made of an antiferromagnetic material and creates exchange coupling with the magnetization fixed layer 51 to fix the direction of the magnetization 51m of the magnetization fixed layer 51. Alternatively, the magnetization fixed layer 51 may be a so-called self-pinned fixed layer (Synthetic Ferri Pinned layer, SFP layer). The self-pinned fixed layer has a laminated ferri structure in which a ferromagnetic layer, a non-magnetic intermediate layer, and a ferromagnetic layer are stacked, and the two ferromagnetic layers are antiferromagnetically coupled.

[0048] Here, we will explain the resistance value of the MR element 50 using the case where the direction of the magnetization 51m of the magnetized fixed layer 51 is the -X direction as an example. Figures 9 and 10 show the free layer 53 when a magnetic field component MFx parallel to the X direction of the target magnetic field MF is applied to the free layer 53.

[0049] Figure 9 shows the free layer 53 when the direction of the magnetic field component MFx is in the X direction. In this case, the center 53c of the magnetic vortex structure moves due to the magnetic field component MFx, and the amount of magnetization 53m oriented in the X direction becomes greater than the amount of magnetization 53m oriented in the -X direction. In this case, the resistance value of the MR element 50 increases.

[0050] Figure 10 shows the free layer 53 when the direction of the magnetic field component MFx is in the -X direction. In this case, the center 53c of the magnetic vortex structure moves due to the magnetic field component MFx, and the amount of magnetization 53m oriented in the -X direction becomes greater than the amount of magnetization 53m oriented in the X direction. In this case, the resistance value of the MR element 50 decreases.

[0051] The change in the resistance of the MR element 50 depends on the strength of the magnetic field component MFx. When the direction of the magnetic field component MFx is in the X direction, as the strength of the magnetic field component MFx increases, the amount of magnetization 53m oriented in the X direction increases. The resistance of the MR element 50 increases as the amount of magnetization 53m oriented in the X direction increases. Also, when the direction of the magnetic field component MFx is in the -X direction, as the strength of the magnetic field component MFx increases, the amount of magnetization 53m oriented in the -X direction increases. The resistance of the MR element 50 decreases as the amount of magnetization 53m oriented in the -X direction increases. When the strength of the magnetic field component MFx increases, the resistance of the MR element 50 changes in a direction in which its increase or decrease increases, respectively. When the strength of the magnetic field component MFx decreases, the resistance of the MR element 50 changes in a direction in which its increase or decrease decreases, respectively. In this embodiment in particular, the relationship between the strength of the magnetic field component MFx and the resistance of the MR element 50 is linear or nearly linear, as long as the requirement that the free layer 53 does not saturate is met.

[0052] Next, referring to Figure 2, the direction of magnetization 51m of the magnetization fixed layer 51 in each of the first to fourth resistance sections R1 to R4 will be explained. In the first resistance section R1, the magnetization 51m of each magnetization fixed layer 51 of the multiple MR elements 50 includes a component in the first magnetization direction. In the second resistance section R2, the magnetization 51m of each magnetization fixed layer 51 of the multiple MR elements 50 includes a component in the second magnetization direction, opposite to the first magnetization direction. In the third resistance section R3, the magnetization 51m of each magnetization fixed layer 51 of the multiple MR elements 50 includes a component in the first magnetization direction. In the fourth resistance section R4, the magnetization 51m of each magnetization fixed layer 51 of the multiple MR elements 50 includes a component in the second magnetization direction. In Figure 2, the two arrows drawn in the first and third resistance sections R1 and R3, respectively, indicate the first magnetization direction. In Figure 2, the two arrows drawn on the second and fourth resistors R2 and R4, respectively, indicate the second magnetization direction. In this embodiment, the first magnetization direction is in the X direction, and the second magnetization direction is in the -X direction.

[0053] Next, with reference to Figure 2, at least one detection signal generated by the magnetic sensor 1 will be described. When the direction of the magnetic field component MFx is the X direction, the resistance values ​​of each of the multiple MR elements 50 in the first and third resistive sections R1 and R3 decrease, and the resistance values ​​of each of the multiple MR elements 50 in the second and fourth resistive sections R2 and R4 increase, compared to the state in which the magnetic field component MFx is absent. As a result, the resistance values ​​of each of the first and third resistive sections R1 and R3 decrease, and the resistance values ​​of each of the second and fourth resistive sections R2 and R4 increase.

[0054] When the direction of the magnetic field component MFx is in the -X direction, the changes in the resistance values ​​of the first to fourth resistance sections R1 to R4 are reversed compared to the case where the direction of the magnetic field component MFx is in the X direction.

[0055] Thus, when the direction and intensity of the magnetic field component MFx change, the resistance values ​​of the first to fourth resistors R1 to R4 change such that the resistance values ​​of the first and third resistors R1 and R3 increase while the resistance values ​​of the second and fourth resistors R2 and R4 decrease, or the resistance values ​​of the first and third resistors R1 and R3 decrease while the resistance values ​​of the second and fourth resistors R2 and R4 increase. As a result, the potential at the connection point of the first and second resistors R1 and R2, i.e., the potential of the first output terminal 13, and the potential at the connection point of the third and fourth resistors R3 and R4, i.e., the potential of the second output terminal 14, change. The magnetic sensor 1 may generate a signal corresponding to the potential of the first output terminal 13 and a signal corresponding to the potential of the second output terminal 14 as detection signals. Alternatively, the magnetic sensor 1 may generate a signal corresponding to the potential difference between the first output terminal 13 and the second output terminal 14 as a detection signal. In this case, the magnetic sensor 1 may further include a differential amplifier (difference detector) that outputs a signal corresponding to the potential difference between the first output terminal 13 and the second output terminal 14 as a detection signal.

[0056] Next, a method for manufacturing the magnetic sensor 1 according to this embodiment will be described with reference to Figures 11 to 15. Figures 11 to 15 show cross-sections of the laminated body during the manufacturing process of the magnetic sensor 1. Here, the method for manufacturing the magnetic sensor 1 will be described focusing on one MR element 50. In the method for manufacturing the magnetic sensor 1, first, an insulating layer (not shown) may be formed on the substrate 10 (see Figure 1). Figure 11 shows the following steps. In this step, first, the lower electrode 41 is formed. Next, an initial MR element 50P, which will later become the MR element 50, is formed on the lower electrode 41. Before forming the initial MR element 50P, a buffer layer (not shown) made of a non-magnetic metal material may be formed on the lower electrode 41.

[0057] Next, an initial protective layer 60P is formed on the initial MR element 50P, which will later become the first portion 60 of the protective layer 70. Then, an inorganic material layer 80 is formed on the initial protective layer 60P. The inorganic material layer 80 has a shape corresponding to the planar shape of the MR element 50. The manufacturing method of the magnetic sensor 1 according to this embodiment will be explained using the case where the inorganic material layer 80 is formed by carbon as an example.

[0058] Figure 12 shows the following process. In this process, the inorganic material layer 80 is used as an etching mask to etch a portion of the initial MR element 50P and the initial protective layer 60P, for example, by ion beam etching. When the initial MR element 50P and the initial protective layer 60P are etched, a re-adhesion film may be formed on the surfaces of the initial MR element 50P and the initial protective layer 60P due to the material scattered by the etching. When using ion beam etching, the re-adhesion film can be removed by tilting the direction of the ion beam relative to the stacking direction. The portion of the initial protective layer 60P that remains after etching becomes the first portion 60 of the protective layer 70.

[0059] Here, the process of fixing the magnetization direction of the magnetization fixed layer 51 will be explained in detail. The initial MR element 50P shown in Figure 11 includes at least an initial magnetization fixed layer which will later become the magnetization fixed layer 51, a free layer 53, and a gap layer 52.

[0060] In the process of fixing the magnetization direction of the magnetization fixing layer 51, after forming the initial MR elements 50P, the magnetization direction of the initial magnetization fixing layer is fixed to the predetermined direction using laser light and an external magnetic field in a predetermined direction. For example, in the case of multiple initial MR elements 50P that will later become the multiple MR elements 50 of the first and third resistive sections R1 and R3, laser light is irradiated onto the multiple initial MR elements 50P while applying an external magnetic field in the first magnetization direction (X direction). If the initial MR elements 50P include an antiferromagnetic layer, the laser light is irradiated such that the temperature of the multiple initial MR elements 50P irradiated with the laser light is above the blocking temperature of the antiferromagnetic layer. The temperature of the multiple initial MR elements 50P can be adjusted, for example, by the intensity or pulse width of the laser light. After irradiation with laser light, when the temperature of the multiple initial MR elements 50P falls below the blocking temperature, the magnetization direction of the initial magnetization fixing layer is fixed to the first magnetization direction. As a result, the initial magnetization fixed layer becomes the magnetization fixed layer 51.

[0061] Furthermore, in the other multiple initial MR elements 50P that will later become the multiple MR elements 50 of the second and fourth resistive sections R2 and R4, by setting the direction of the external magnetic field to the second magnetization direction (-X direction), the magnetization direction of each initial magnetization fixed layer of the other multiple initial MR elements 50P can be fixed to the second magnetization direction.

[0062] The step of fixing the magnetization direction of the initial magnetization fixed layer described above may be performed after the etching step of the initial MR element 50P shown in Figure 12. In this case, by fixing the magnetization direction of the initial magnetization fixed layer, the initial magnetization fixed layer becomes the magnetization fixed layer 51. Alternatively, the step of fixing the magnetization direction of the initial magnetization fixed layer described above may be performed before the etching step of the initial MR element 50P shown in Figure 12. In this case, the initial magnetization fixed layer is also etched by etching the initial MR element 50P. As a result, the initial magnetization fixed layer becomes the magnetization fixed layer 51.

[0063] In Figure 12, the side surface of the MR element 50 is inclined with respect to the direction parallel to the Z direction. The side surface of the MR element 50 may include multiple portions, each with a different angle with respect to the direction parallel to the Z direction. Alternatively, at least a portion of the side surface of the MR element 50 may be parallel or nearly parallel to the Z direction.

[0064] Furthermore, in Figure 12, the side surface 60d of the first portion 60 of the protective layer 70 is inclined with respect to the direction parallel to the Z direction. The angle that the side surface 60d of the first portion 60 makes with respect to the direction parallel to the Z direction may be the same as or different from the angle that the side surface of the MR element 50 makes with respect to the direction parallel to the Z direction. Also, the side surface 60d of the first portion 60 may include multiple portions, each with a different angle with respect to the direction parallel to the Z direction. Alternatively, at least a portion of the side surface 60d of the first portion 60 may be parallel or nearly parallel to the Z direction.

[0065] Figure 13 shows the next step. In this step, an insulating layer 30 is formed to cover the lower electrode 41, the MR element 50, the first portion 60, and the inorganic material layer 80. The insulating layer 30 is formed such that the upper surface of the insulating layer 30 is positioned above the upper surface of the inorganic material layer 80.

[0066] Figure 14 shows the following steps. In this step, a portion of the insulating layer 30 is polished, for example by chemical mechanical polishing (hereinafter referred to as CMP). The insulating layer 30 may be polished to a position where, for example, the upper surface of the inorganic material layer 80 is not exposed. Next, a photoresist mask (not shown) is formed on the insulating layer 30. The photoresist mask (not shown) has openings with shapes corresponding to the openings 80a of the inorganic material layer 80 that are formed later. Next, using the photoresist mask (not shown), a portion of the insulating layer 30 is selectively etched, for example by reactive ion etching (hereinafter referred to as RIE). The etching of the insulating layer 30 is carried out until the upper surface of the inorganic material layer 80 is exposed.

[0067] Next, at least a portion of the inorganic material layer 80 is selectively etched. In this embodiment, in particular, a portion of the inorganic material layer 80 is etched so that an opening 80a is formed in the inorganic material layer 80. If the inorganic material layer 80 is made of carbon, the inorganic material layer 80 is etched by RIE using an etching gas containing O2. The etching of the inorganic material layer 80 is carried out until the second surface 60b of the first portion 60 of the protective layer 70 is exposed.

[0068] In addition, during the etching process of the inorganic material layer 80, a portion of the first portion 60 may be etched together with the inorganic material layer 80. If the first portion 60 is etched, a recess 60c may be formed in the first portion 60, having a depth that extends from the second surface 60b toward the first surface 60a but does not reach the first surface 60a. In the example shown in Figure 14, the first portion 60 has a recess 60c. In this embodiment in particular, the outer diameter of the planar shape of the recess 60c is smaller than the outer diameter of the inorganic material layer 80. The area of ​​the contact surface between the upper electrode 42, which is formed later, and the first portion 60 of the protective layer 70 is equal to the area of ​​the planar shape of the recess 60c.

[0069] Furthermore, as described above, when the inorganic material layer 80 is etched by RIE using an etching gas containing O2, an oxide film is formed on the second surface 60b of the first portion 60. Therefore, in this case, it is preferable to remove the oxide film after etching the inorganic material layer 80, for example, by using ion beam etching or reverse sputtering.

[0070] The portion of the second surface 60b other than the recess 60c is covered with the inorganic material layer 80. Therefore, the surface condition of the recess 60c and the surface condition of the portion other than the recess 60c are different from each other. For example, the surface roughness of the surface of the recess 60c and the surface roughness of the portion other than the recess 60c may be different from each other. Any index can be used as an index of surface roughness.

[0071] Figure 15 shows the following steps. In this step, first, a base layer 421 is formed along the surface of the second surface 60b or recess 60c of the first portion 60, the wall surface of the opening 80a of the inorganic material layer 80, and the surface of the insulating layer 30. If the first portion 60 has a recess 60c, at least a portion of the second portion 421A of the base layer 421 is provided within the recess 60c. The base layer 421 is formed, for example, by electroless plating or sputtering.

[0072] Next, a conductive layer 422 is formed on the base layer 421. The conductive layer 422 is formed, for example, by electroplating. The base layer 421 is used as an electrode and seed layer when forming the conductive layer 422 by electroplating. Next, the base layer 421 and the conductive layer 422 are polished, for example by CMP, until the insulating layer 30 is exposed. This completes the upper electrode 42.

[0073] The conductive layer 422 may be formed to completely fill the opening 80a of the inorganic material layer 80, or it may be formed not to completely fill it. In the latter case, voids may be formed in the conductive layer 422.

[0074] Up to this point, we have described the manufacturing method of the magnetic sensor 1, focusing on a single MR element 50. In the manufacturing method of the magnetic sensor 1, multiple MR elements 50, multiple lower electrodes 41, and multiple upper electrodes 42 are formed. After the multiple upper electrodes 42 are formed, the magnetic sensor 1 is completed by forming a power terminal 11, a ground terminal 12, and multiple terminals corresponding to the first and second output terminals 13 and 14, as well as wiring to connect the multiple terminals to the multiple MR elements 50.

[0075] Next, the operation and effects of the magnetic sensor 1 according to this embodiment will be described. In this embodiment, in order to form the conductive layer 422 which constitutes a part of the upper electrode 42, it is necessary to form an opening 80a in the inorganic material layer 80. As mentioned above, when an opening 80a is formed in the inorganic material layer 80, the second surface 60b of the first portion 60 of the protective layer 70 is exposed. If the protective layer 70 is not provided, the upper surface of the MR element 50 will be exposed when the inorganic material layer 80 is etched. Depending on the etching conditions of the inorganic material layer 80, it may be necessary to etch the upper surface of the MR element 50 after etching the inorganic material layer 80, for example, by ion beam etching or reverse sputtering. Depending on the conditions of ion beam etching or reverse sputtering, the free layer 53 of the MR element 50 may be damaged. In this embodiment in particular, if the free layer 53 is damaged, the magnetic vortex structure cannot be formed accurately, and as a result, the hysteresis characteristics of the MR element 50 may deteriorate.

[0076] In contrast, in this embodiment, a protective layer 70 is provided on the MR element 50. This makes it possible to suppress problems arising from the formation of the conductive layer 422.

[0077] Furthermore, the conductive layer 422 has a relatively large volume. If the conductive layer 422 is in direct contact with the MR element 50, the free layer 53 may be damaged due to differences in characteristics between the conductive layer 422 and other components. In contrast, in this embodiment, the conductive layer 422 is not in contact with the MR element 50. In particular, in this embodiment, the protective layer 70 includes a first portion 60 and a second portion 421A. The conductive layer 422 is in contact with the second portion 421A. As a result, according to this embodiment, the conductive layer 422 can be kept further away from the MR element 50 compared to the case where the second portion 421A is not provided. Consequently, according to this embodiment, the occurrence of problems caused by the conductive layer 422 can be suppressed.

[0078] Incidentally, as a method for forming the MR element 50 and the upper electrode 42, a method using a photoresist mask instead of an inorganic material layer 80 can be considered. Hereinafter, the method using a photoresist mask will be referred to as the comparative example formation method. In the comparative example formation method, first, a photoresist mask is formed on the initial MR element 50P. The photoresist mask has a shape corresponding to the planar shape of the MR element 50.

[0079] A photoresist mask is used that includes a lower layer and an upper layer placed on top of the lower layer. The upper layer is formed of a photoresist patterned by photolithography. The lower layer is formed of a material that is dissolved by the developer used when patterning the upper layer, for example. Such a photoresist mask has an undercut that creates a space between it and the substrate.

[0080] In the comparative example's formation method, the initial MR element 50P is then etched by ion beam etching using a photoresist mask. This transforms the initial MR element 50P into MR element 50. Next, an insulating layer 30 is formed on the entire upper surface of the laminate, leaving the photoresist mask in place. Then, the photoresist mask is removed. Finally, an upper electrode 42 is formed on the MR element 50 and the insulating layer 30.

[0081] To form a magnetic vortex structure in the free layer 53, it is necessary to increase the thickness of the free layer 53. When the initial MR element 50P containing a thick free layer 53 is etched, the amount of re-adhesion film formed by material scattered by etching increases, so it is necessary to reduce the width of the lower layer of the photoresist mask. However, if this is done, the photoresist mask may tip over during etching. If the insulating layer 30 is formed while the photoresist mask is tilted, the insulating layer 30 formed around the MR element 50 and the insulating layer 30 formed on the surface of the photoresist mask will connect, making it impossible to remove the photoresist mask. Also, if the insulating layer 30 is formed while the photoresist mask is tilted, the insulating layer 30 may not be sufficiently formed around the MR element 50. In this case, the MR element 50 may be damaged by the stripping solution when removing the photoresist mask.

[0082] In contrast, in this embodiment, as described above, the MR element 50 and the upper electrode 42 are formed using an inorganic material layer 80. This makes it possible to avoid the problems caused by the photoresist mask as described above.

[0083] Next, other effects of the magnetic sensor 1 according to this embodiment will be described. The thickness of the first portion 60 of the protective layer 70 may be within the range of 40 to 100% of the thickness of the free layer 53 of the MR element 50. In this case, the damage to the free layer 53 during the etching process of the inorganic material layer 80 can be reduced.

[0084] Alternatively, the thickness of the first portion 60 of the protective layer 70 may be within the range of 20-40% of the thickness of the free layer 53 of the MR element 50. In this case, the overall thickness of the magnetic sensor 1 can be reduced.

[0085] [Differentiation] Next, a modified example of this embodiment will be described with reference to Figure 16. Figure 16 is a cross-sectional view showing a part of a modified example of the magnetic sensor 1. In the modified example, the angle that the side surface 60d of the first portion 60 of the protective layer 70 makes with respect to the direction parallel to the Z direction is greater than the angle that the side surface of the MR element 50 makes with respect to the direction parallel to the Z direction.

[0086] [Second Embodiment] Next, a second embodiment of the present disclosure will be described. First, a method for manufacturing the magnetic sensor 1 according to this embodiment will be described with reference to Figures 17 to 19. Figures 17 to 19 show cross-sections of the laminated body during the manufacturing process of the magnetic sensor 1.

[0087] The method for manufacturing the magnetic sensor 1 according to this embodiment is the same as in the first embodiment up to the step of forming the insulating layer 30. Figure 17 shows the next step. In this step, the insulating layer 30 is polished, for example by CMP, until the inorganic material layer 80 is exposed.

[0088] Figure 18 shows the following step. In this step, the inorganic material layer 80 is removed. If the inorganic material layer 80 is made of carbon, it is removed by ashing using an ashing gas containing O2, for example. In this embodiment, in particular, the entire or almost entire inorganic material layer 80 is removed. By removing the inorganic material layer 80, a contact hole is formed in the insulating layer 30 for connecting the MR element 50 to the upper electrode 42. At this time, the inorganic material layer 80 may be completely removed from the second surface 60b of the first portion 60. That is, the entire second surface 60b of the first portion 60 may be exposed.

[0089] In addition, during the etching process of the inorganic material layer 80, a portion of the first portion 60 may be etched together with the inorganic material layer 80. When the first portion 60 is etched, a recess may be formed in the first portion 60 that extends from the second surface 60b toward the first surface 60a but does not reach the first surface 60a.

[0090] Furthermore, as described above, when the inorganic material layer 80 is removed by ashing using an ashing gas containing O2, an oxide film is formed on the second surface 60b of the first portion 60. Therefore, in this case, it is preferable to remove the oxide film after removing the inorganic material layer 80, for example, by using ion beam etching or reverse sputtering.

[0091] Figure 19 shows the following steps. In this step, a base layer 421 is formed along the second surface 60b of the first portion 60 and the surface of the insulating layer 30. Next, a conductive layer 422 is formed on top of the base layer 421. The subsequent steps are the same as in the first embodiment.

[0092] Next, referring to Figure 19, the differences between the configuration of the magnetic sensor 1 according to this embodiment and that of the first embodiment will be described. In this embodiment, the outer edge 421Ae of the second portion 421A coincides with or nearly coincides with the outer edge of the second surface 60b of the first portion 60 when viewed from the Z direction. Alternatively, the outer edge 421Ae of the second portion 421A may be located inside the outer edge of the first surface 60a of the first portion 60 when viewed from the Z direction.

[0093] In this embodiment, the planar shape of the portion of the upper electrode 42 located within the contact hole of the insulating layer 30 is the same as or approximately the same as the planar shape of the first portion 60 of the protective layer 70. As a result, according to this embodiment, the contact area between the first portion 60 and the upper electrode 42 (second portion 421A) can be increased. Consequently, according to this embodiment, the overall resistance value of the magnetic sensor 1 can be reduced.

[0094] Other configurations, operations, and effects in this embodiment are the same as those in the first embodiment.

[0095] [Third Embodiment] Next, a third embodiment of the present disclosure will be described with reference to Figure 20. Figure 20 is an enlarged cross-sectional view showing a part of the magnetic sensor 1 according to this embodiment. The configuration of the magnetic sensor 1 according to this embodiment differs from the first embodiment in the following respects. In this embodiment, an inorganic material layer 180 is included instead of the inorganic material layer 80 in the first embodiment. The shape and arrangement of the inorganic material layer 180 are the same as those of the inorganic material layer 80. The inorganic material layer 180 is formed of, for example, Al2O3.

[0096] Furthermore, if the inorganic material layer 180 is formed of Al2O3, it is preferable that the first portion 60 of the protective layer 70 includes a metal film made of a Ni-based nonmagnetic alloy such as NiCr or Ru. The Ni-based nonmagnetic alloy or Ru metal film functions as an etching stopper in the etching process of the inorganic material layer 180. In the example shown in Figure 20, the first portion 60 includes a first layer 61, a second layer 62, and a third layer 63 stacked in this order on the MR element 50. The inorganic material layer 180 is located on the third layer 63. In the example shown in Figure 20, the third layer 63 may be a metal film made of NiCr.

[0097] In the example shown in Figure 20, the base layer 421 includes a first layer 4211 and a second layer 4212 laminated on top of the first layer 4211. In this case, the second layer 62 and the second layer 4212 may be a first metal film made of a first metallic material. The first layer 61 and the first layer 4211 may be formed from the same metallic material, or they may be formed from different metallic materials. In one example, the first layer 61 is a metal film made of Ru, the second layer 62 is a metal film made of Ta, the third layer 63 is a metal film made of NiCr, the first layer 4211 is a metal film made of Ti, and the second layer 4212 is a metal film made of Ta.

[0098] Other configurations, operations, and effects in this embodiment are the same as those in the first embodiment.

[0099] [Fourth Embodiment] Next, a fourth embodiment of the present disclosure will be described with reference to Figure 21. Figure 21 is an enlarged cross-sectional view showing a part of the magnetic sensor 1 according to this embodiment. The configuration of the magnetic sensor 1 according to this embodiment differs from the third embodiment in the following respects. In this embodiment, the inorganic material layer 180 has an opening 180a that exposes a part of the second surface 60b of the first portion 60 of the protective layer 70. The size of the opening 180a in the cross-section of the inorganic material layer 180 parallel to the XY plane may be constant regardless of the distance from the second surface 60b, or it may increase as it moves away from the second surface 60b.

[0100] In this embodiment, in particular, the planar shape of the opening 180a of the inorganic material layer 180 is larger than the planar shape of the second portion 421A of the protective layer 70. An insulating layer 30 is interposed between the wall surface of the opening 180a of the inorganic material layer 180 and the second portion 421A of the protective layer 70, and between the wall surface of the opening 180a of the inorganic material layer 180 and portion 421B of the base layer 421.

[0101] The insulating layer 30 has an opening 30a that exposes a portion of the second surface 60b of the first portion 60 of the protective layer 70. The size of the opening 30a in the cross-section of the insulating layer 30 parallel to the XY plane may be constant regardless of the distance from the second surface 60b, or it may increase as it moves away from the second surface 60b.

[0102] The underlayer 421, including the second portion 421A, is positioned along the wall surface of the opening 30a of the insulating layer 30 and a portion of the second surface 60b.

[0103] The outer diameter of the planar shape of the recess 60c of the first portion 60 is smaller than the inner diameter of the planar shape of the opening 180a of the inorganic material layer 180, and is the same as or approximately the same as the outer diameter of the planar shape of the opening 30a of the insulating layer 30.

[0104] Other configurations, operations, and effects in this embodiment are the same as those in the third embodiment.

[0105] This disclosure is not limited to the embodiments described above, and various modifications are possible. For example, the shape of the side surface of the MR element 50 and the shape of the side surface 60d of the first portion 60 are not limited to the examples shown in each embodiment. For example, the side surface of the MR element 50 may include a curved portion. Similarly, the side surface 60d of the first portion 60 may include a curved portion.

[0106] As described above, the magnetic sensor of this disclosure comprises a magnetoresistive element including a magnetization-fixed layer having a magnetization with a fixed direction, a free layer having a magnetization that can change in response to an applied magnetic field, and a gap layer disposed between the magnetization-fixed layer and the free layer; a protective layer disposed on the magnetoresistive element; and a conductive layer electrically connected to the magnetoresistive element. The protective layer includes a first portion and a second portion sandwiching the first portion between itself and the magnetoresistive element. When viewed from the stacking direction of the magnetization-fixed layer, the gap layer, and the free layer, the outer edge of the second portion lies inside the outer edge of the first portion. The conductive layer is in contact with the second portion.

[0107] The magnetic sensor of this disclosure may further include electrodes. The electrodes may include a conductive layer and a base layer that underlies the conductive layer. The base layer may include a second portion of a protective layer.

[0108] Furthermore, in the magnetic sensor of this disclosure, the first portion may include a first metal film made of a first metal material. The second portion may include a second metal film made of a first metal material. The protective layer may further include a third metal film made of a second metal material.

[0109] Furthermore, in the magnetic sensor of this disclosure, the first portion may have a first surface and a second surface located at both ends in the stacking direction. The first surface may face a magnetoresistive element. The second surface may face a second portion. The first portion may further have a recess that is recessed from the second surface toward the first surface. At least a portion of the second portion may be provided within the recess.

[0110] Furthermore, the magnetic sensor of this disclosure may further include an inorganic material layer disposed on the first portion of the protective layer. The outer diameter of the planar shape of the recess when viewed from the stacking direction may be smaller than the outer diameter of the planar shape of the inorganic material layer when viewed from the stacking direction. The outer diameter of the planar shape of the inorganic material layer may be less than or equal to the outer diameter of the planar shape of the magnetoresistive element when viewed from the stacking direction.

[0111] Furthermore, the magnetic sensor of this disclosure may further include electrodes. The electrodes may include a conductive layer and a base layer that serves as a base for the conductive layer. The base layer may include a second portion of the protective layer. The electrodes may be in contact with a first portion of the protective layer. The area of ​​the contact surface between the electrodes and the first portion of the protective layer may be equal to the area of ​​the planar shape of the recess when viewed from the lamination direction.

[0112] Furthermore, in the magnetic sensor of this disclosure, the thickness of the first portion of the protective layer in the stacking direction may be within the range of 40 to 100% of the thickness of the free layer in the stacking direction. Alternatively, the thickness of the first portion of the protective layer in the stacking direction may be within the range of 20 to 40% of the thickness of the free layer in the stacking direction.

[0113] Furthermore, in the magnetic sensor of this disclosure, the free layer may have a magnetic vortex structure and may be configured so that the center of the magnetic vortex structure moves in accordance with the target magnetic field. [Explanation of Symbols]

[0114] 1...Magnetic sensor, 30...Insulating layer, 41...Lower electrode, 42...Upper electrode, 50...MR element, 51m...Magnetization, 51...Magnetization fixed layer, 52...Gap layer, 53...Free layer, 53m...Magnetization, 60...First part, 70...Protective layer, 80...Inorganic material layer, 421...Underlayment layer, 421A...Second part, 422...Conductive layer, R1~R4...Resistive part.

Claims

1. A magnetoresistive element comprising a magnetization fixed layer having a magnetization with a fixed direction, a free layer having a magnetization that can change in response to an applied magnetic field, and a gap layer disposed between the magnetization fixed layer and the free layer, A protective layer disposed on the magnetoresistive element, The magnetoresistive element comprises a conductive layer electrically connected to the magnetoresistive element, The protective layer includes a first portion and a second portion that sandwiches the first portion between itself and the magnetoresistive element. When viewed from the stacking direction of the magnetization fixed layer, the gap layer, and the free layer, the outer edge of the second portion lies inside the outer edge of the first portion. The magnetic sensor is characterized in that the conductive layer is in contact with the second portion.

2. Furthermore, equipped with electrodes, The electrode includes the conductive layer and a base layer that serves as a base for the conductive layer. The magnetic sensor according to claim 1, characterized in that the underlying layer includes the second portion of the protective layer.

3. The first portion includes a first metal film made of a first metal material, The magnetic sensor according to claim 1, characterized in that the second portion includes a second metal film made of the first metal material.

4. The magnetic sensor according to claim 3, characterized in that the protective layer further includes a third metal film made of a second metal material.

5. The first portion has a first surface and a second surface located at both ends in the stacking direction, The first surface faces the magnetoresistive element, The second surface faces the second portion, The first portion further has a recess that is recessed from the second surface toward the first surface, The magnetic sensor according to claim 1, characterized in that at least a portion of the second part is provided within the recess.

6. Furthermore, the magnetic sensor according to claim 5 is characterized by comprising an inorganic material layer disposed on the first portion of the protective layer and around the second portion.

7. The magnetic sensor according to claim 6, characterized in that the outer diameter of the planar shape of the recess when viewed from the stacking direction is smaller than the outer diameter of the planar shape of the inorganic material layer when viewed from the stacking direction.

8. The magnetic sensor according to claim 7, characterized in that the outer diameter of the planar shape of the inorganic material layer is less than or equal to the outer diameter of the planar shape of the magnetoresistive element when viewed from the stacking direction.

9. Furthermore, it is equipped with electrodes, The electrode includes the conductive layer and a base layer that serves as a base for the conductive layer. The aforementioned underlayer includes the second portion of the protective layer, The electrode is in contact with the first portion of the protective layer, The magnetic sensor according to claim 5, characterized in that the area of ​​the contact surface between the electrode and the first portion of the protective layer is equal to the area of ​​the planar shape of the recess when viewed from the stacking direction.

10. The magnetic sensor according to claim 1, characterized in that the thickness of the first portion of the protective layer in the lamination direction is within the range of 40 to 100% of the thickness of the free layer in the lamination direction.

11. The magnetic sensor according to claim 1, characterized in that the thickness of the first portion of the protective layer in the lamination direction is within the range of 20 to 40% of the thickness of the free layer in the lamination direction.

12. The magnetic sensor according to any one of claims 1 to 11, characterized in that the free layer can have a magnetic vortex structure and is configured so that the center of the magnetic vortex structure moves in accordance with the target magnetic field.

Images