Magnetic sensor

Abstract

A magnetic sensor 100 according to the present invention, which is capable of efficiently applying an induced magnetic field from wiring disposed in the vicinity of a magneto-resistive element, comprises a first magnetic body 31 and a second magnetic body 32 which are disposed separated from one another in a first direction, the magneto-resistive element 10a, which has a sensitivity axis along the first direction and which is positioned between the first magnetic body 31 and the second magnetic body 32 in the first direction, first wiring 21, 22 which is positioned on a second direction side, perpendicular to the first direction, of the first magnetic body 10a, and which, when energized, causes magnetic flux passing through the first magnetic body 10 to generate an induced magnetic field having a component in the first direction, and an insulating portion 50 which is positioned between the first wiring 21, 22 and the first magnetic body 31, wherein: the insulating portion 50 may include a diffusion suppressing portion; and the first wiring 21, 22 may be provided on both sides of the first magnetic body 31 in the second direction.

Description

magnetic sensor

[0001] The present invention relates to a magnetic sensor.

[0002] Patent Document 1 discloses a magnetic sensor having a substrate and a laminated section arranged on the substrate, the laminated section including a magnetization free layer whose magnetization changes in response to an external magnetic field, a magnetization fixed layer whose magnetization is fixed in a first direction, and a non-magnetic layer arranged between the magnetization free layer and the magnetization fixed layer, the magnetic sensor comprising: a magnetic sensing unit that outputs a signal in response to the external magnetic field; and a magnetic field generating unit that applies a bias magnetic field to the magnetization free layer, wherein when the bias magnetic field is not applied to the magnetization free layer, the magnetization direction of the magnetization free layer is approximately parallel or approximately anti-parallel to the first direction, and the magnetic sensor is configured to calculate the component of the external magnetic field in the second direction based on a first output which is the output of the magnetic sensing unit in a state where a first bias magnetic field including a positive component is applied to the magnetization free layer in a second direction perpendicular to the first direction in a top view, and a second output which is the output of the magnetic sensing unit in a state where a second bias magnetic field including a negative component is applied to the magnetization free layer.

[0003] In the invention disclosed in Patent Document 1, a specific example of a magnetic field generating unit is a wiring provided in the stacking direction of the stacked unit, and an induced magnetic field from the current-carrying wiring is applied to the magnetization free layer of the stacked unit as a bias magnetic field. The external magnetic field is measured while receiving bias magnetic fields with different application directions, and 1 / f noise is removed based on these measurement results.

[0004] Japanese Patent Application Laid-Open No. 2018-115972

[0005] When measuring an external magnetic field while receiving an induced magnetic field from wiring placed near a magnetoresistive element, as in the magnetic sensor disclosed in Patent Document 1, it can be difficult to increase the strength of the induced magnetic field by increasing the amount of current flowing through the wiring due to reasons such as the small cross-sectional area of ​​the wiring and the structural difficulty of dissipating Joule heat from the wiring.

[0006] SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a magnetic sensor capable of efficiently applying an induced magnetic field from wiring arranged in the vicinity of a magnetoresistive element.

[0007] A magnetic sensor according to one aspect of the present invention for solving the above problem comprises a first magnetic body and a second magnetic body arranged at a distance in a first direction, a magnetoresistive effect element having a sensitivity axis along the first direction and positioned between the first magnetic body and the second magnetic body in the first direction, a first wiring positioned on the first magnetic body in a second direction perpendicular to the first direction, and causing a magnetic flux passing through the first magnetic body to generate an induced magnetic field having a component in the first direction when current is applied, and an insulating portion positioned between the first wiring and the first magnetic body.

[0008] Since the bias magnetic field generated by passing current through the wiring can be applied efficiently to the magnetoresistive element, the current density in the wiring can be reduced, and therefore Joule heat generated from the wiring can be reduced.

[0009] The magnetic sensor may include a second wiring disposed on the second direction side of the second magnetic body via the insulating portion, the second wiring causing, when current is applied, an induced magnetic field in which magnetic flux passing through the second magnetic body has a component in the first direction. In this case, the orientation of the first direction component of the magnetic flux passing through the first magnetic body based on the induced magnetic field generated by applying current to the first wiring may be equal to the orientation of the first direction component of the magnetic flux passing through the second magnetic body based on the induced magnetic field generated in the second magnetic body by applying current to the second wiring. In the magnetic sensor, the insulating portion may include a diffusion suppression portion. By using the insulating portion as a diffusion suppression portion, material transfer (diffusion) between the wiring and the magnetic body is suppressed, thereby suppressing performance degradation due to the diffusion. The diffusion is expected to occur during manufacturing (particularly when heated) and during use (changes over time). In the magnetic sensor, the first wiring may be provided on both sides of the first magnetic body in the second direction. In the magnetic sensor, the second wiring may be provided on both sides of the second magnetic body in the second direction. The above magnetic sensor may include a first magnetic field convergence portion provided on a side of the first wiring opposite to a side facing the first magnetic body and including a ferromagnetic material. The above magnetic sensor may include a second magnetic field convergence portion provided on a side of the second wiring opposite to a side facing the second magnetic body and including a ferromagnetic material. The above magnetic sensor may include a first magnetic field convergence portion provided on a side of the first wiring opposite to a side facing the first magnetic body and including a ferromagnetic material. In the above magnetic sensor, the magnetoresistive effect element may not overlap with either the first magnetic field convergence portion or the second magnetic field convergence portion when viewed in the second direction. In the above magnetic sensor, the first magnetic field convergence portion and the second magnetic field convergence portion may be connected in the first direction.

[0010] According to the present invention, a magnetic sensor is provided that can efficiently apply an induced magnetic field from wiring arranged in the vicinity of a magnetoresistive element.

[0011] FIG. 2 is a circuit diagram of a magnetic sensor according to one embodiment of the present invention. FIG. 3 is a cross-sectional view taken along line AA' in FIG. 1. FIG. 4 is a diagram illustrating an induced magnetic field generated by passing current through wiring. FIG. 5 is a cross-sectional view illustrating the structure of a magnetic sensor according to another embodiment of the present invention. FIG. 6 is a cross-sectional view illustrating the structure of a modified example (part 1) of a magnetic sensor according to another embodiment of the present invention. FIG. 7 is a cross-sectional view illustrating the structure of a modified example (part 2) of a magnetic sensor according to another embodiment of the present invention. FIG. 8 is a cross-sectional view illustrating the structure of a modified example (part 3) of a magnetic sensor according to another embodiment of the present invention. FIG. 9 is a cross-sectional view illustrating the structure of a modified example (part 4) of a magnetic sensor according to another embodiment of the present invention. FIG. 10 is a cross-sectional view illustrating the structure of a magnetic sensor according to the prior art. FIG. 11 is a diagram illustrating a simulation result of a magnetic field generated by first magnetic field generation unit MG1x. FIG. 12 is a diagram illustrating a simulation result of a magnetic field generated by first magnetic field generation unit MG1b. FIG. 13 is a diagram illustrating a simulation result of a magnetic field generated by first magnetic field generation unit MG1a. FIG. 14 is a diagram illustrating a simulation result of a magnetic field generated by first magnetic field generation unit MG1c.

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals, and the description of components that have already been described will be omitted as appropriate.

[0013] FIG. 1 is a circuit diagram of a magnetic sensor according to one embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line A-A' in FIG. 1. As shown in FIG. 1, a magnetic sensor 100 according to one embodiment of the present invention includes magnetoresistive effect elements 10a, 10b, 10c, and 10d (when not distinguishing between them, they will be referred to as magnetoresistive effect elements 10 as appropriate). The four magnetoresistive effect elements 10 may be provided on the same substrate (one chip). In this embodiment, the four magnetoresistive effect elements 10 are provided on the same substrate (not shown), and FIG. 1 is a view of the magnetic sensor 100 as viewed from the stacking surface (front surface) of the substrate in the normal direction of the substrate. That is, in FIG. 1, the Z1 side in the Z1-Z2 direction is the front surface of the substrate, and the Z1-Z2 side in the Z1-Z2 direction is the back surface of the substrate. The Z1-Z2 direction is along the stacking direction of the magnetoresistive effect elements 10.

[0014] The magnetic sensor 100 is configured such that a first half-bridge circuit, in which a magnetoresistive effect element 10a and a magnetoresistive effect element 10b, both of which extend in the Y1-Y2 direction, are connected in series, and a second half-bridge circuit, in which a magnetoresistive effect element 10c and a magnetoresistive effect element 10d, both of which extend in the Y1-Y2 direction, are connected in parallel between a power supply terminal Vdd, which is a power supply feeding point, and a ground terminal GND.

[0015] The first half-bridge circuit has an output terminal V1 between the magnetoresistive element 10a and the magnetoresistive element 10b. The second half-bridge circuit has an output terminal V2 between the magnetoresistive element 10c and the magnetoresistive element 10d. The magnitude of the external magnetic field applied from the outside as the detection magnetic field H can be quantitatively measured from the potential difference (Va-Vb, midpoint potential difference) between the outputs of these two output terminals V1 and V2.

[0016] The pair of magnetoresistive effect elements 10a and 10b forming the first half-bridge circuit have the magnetization directions of the pinned magnetic layers 11 oriented in the X1-X2 direction (X2 direction) and the X1-X2 direction (X1 direction), respectively, as shown by the outline arrows in Fig. 1. The pair of magnetoresistive effect elements 10c and 10d forming the second half-bridge circuit have the magnetization directions of the pinned magnetic layers 11 oriented in the X1-X2 direction (X1 direction) and the X1-X2 direction (X2 direction), respectively, as shown by the outline arrows in Fig. 1.

[0017] In the first half-bridge circuit and the second half-bridge circuit, the magnetization directions of the pinned magnetic layers 11 of the magnetoresistive effect elements 10a and 10c on the ground terminal GND side are opposite (anti-parallel). Also, the magnetization directions of the pinned magnetic layers 11 of the magnetoresistive effect elements 10b and 10d on the power supply terminal Vdd side are opposite (anti-parallel). Therefore, the sensitivity axis direction of the magnetoresistive effect element 10 is the X1-X2 direction, which is also referred to as the "first direction" in this specification.

[0018] The four magnetoresistive elements 10a to 10d have the same magnetization direction (direction of the bias magnetic field) of the free magnetic layer 12 when no external magnetic field is applied, and are aligned along the Y1-Y2 direction, as shown by the black arrow in Figure 1.

[0019] With the above-described configuration, the output terminal V1 from the first half-bridge circuit and the output terminal V2 from the second half-bridge circuit change in opposite directions as the magnitude of the detected magnetic field H in the X1-X2 direction changes. Therefore, a large output is obtained as the potential difference between the two output terminals V1 and V2. Therefore, the magnetic sensor 100 can detect the detected magnetic field H with high accuracy. Note that instead of the full-bridge circuit, a first or second half-bridge circuit or a magnetoresistance effect element 10 can also be used.

[0020] 2, the magnetoresistive element 10a may be, for example, a GMR element (giant magnetoresistive element) or a TMR element (tunneling magnetoresistive element), and includes a pinned magnetic layer 11, a free magnetic layer 12, and an intermediate layer 13 formed between the pinned magnetic layer 11 and the free magnetic layer 12. The resistance value of the magnetoresistive element 10a varies depending on the relative relationship between the magnetization directions of the pinned magnetic layer 11, whose magnetization direction is fixed, and the free magnetic layer 12, whose magnetization direction changes in response to an external magnetic field. The magnetic sensor 100 can measure the direction and strength of the external magnetic field to be measured based on the change in the resistance value of the magnetoresistive element 10a.

[0021] When the magnetoresistive element 10a is a GMR element, the pinned magnetic layer 11 is made of a ferromagnetic layer such as a CoFe alloy (cobalt-iron alloy). The free magnetic layer 12 is made of a soft magnetic material such as a CoFe alloy or a NiFe alloy (nickel-iron alloy) and has a single-layer structure, a laminated structure, a laminated ferrimagnetic structure, or the like. The intermediate layer 13 is a nonmagnetic intermediate layer made of a nonmagnetic material such as Cu.

[0022] To stabilize the output of the magnetic sensor 100, a bias magnetic field is applied to the free magnetic layer 12 in a direction perpendicular to the sensitivity axis direction (first direction) along the X1-X2 direction. In the magnetic sensor 100 according to this embodiment, the direction of the bias magnetic field is the Y1-Y2 direction, as shown in FIG. 1 . This allows the magnetization direction of the soft magnetic material forming the free magnetic layer 12 to be aligned when no magnetic field is applied.

[0023] As described above, the magnetization direction of the pinned magnetic layer 11 of the magnetoresistive element 10a is pinned in the X2 direction (X1-X2 direction), and the magnetization direction of the free magnetic layer 12 when no magnetic field is applied is in the Y2 direction (Y1-Y2 direction), which is perpendicular to the magnetization direction of the pinned magnetic layer 11. Therefore, the resistance value of the magnetoresistive element 10a changes in the opposite direction depending on whether the direction of the detected magnetic field H is the X1 direction or the X2 direction in the X1-X2 direction. In other words, because the resistance value is an odd function of the detected magnetic field H in the X1-X2 direction, the direction and magnitude of the detected magnetic field H can be continuously measured.

[0024] A TMR element may be used as the magnetoresistive element 10a instead of the GMR element described above. In this case, the intermediate layer 13 is an insulating barrier layer made of MgO, Al2O3, titanium oxide, or the like.

[0025] The magnetoresistive effect elements 10b to 10d have the same basic structure as the magnetoresistive effect element 10a. From the viewpoint of improving measurement accuracy, it is preferable that the magnetoresistive effect elements 10a to 10d are manufactured on the same substrate using a common manufacturing process.

[0026] 1, a first magnetic field generating unit MG1 is provided around the magnetoresistive elements 10a and 10b, and a second magnetic field generating unit MG2 is provided around the magnetoresistive elements 10c and 10d. In the magnetic sensor 100, the first magnetic field generating unit MG1 and the second magnetic field generating unit MG2 have the same structure.

[0027] As shown in FIG. 2, the first magnetic field generating unit MG1 includes first wirings 21, 22, a first magnetic body 31, and first magnetic field convergence units 41, 42 arranged on the X2 side of the magnetoresistive effect element 10a in the X1-X2 direction (first direction), second wirings 23, 24, a second magnetic body 32, and second magnetic field convergence units 43, 44 arranged on the X1 side of the X1-X2 direction (first direction), and an insulating unit 50 arranged at least between the first wirings 21, 22 and the first magnetic body 31, and between the second wirings 23, 24 and the second magnetic body 32.

[0028] The first magnetic body 31 and the second magnetic body 32 extending in the Y1-Y2 direction are made of a soft magnetic body such as permalloy and are arranged spaced apart in the first direction. The magnetoresistive effect element 10a is located between the first magnetic body 31 and the second magnetic body 32 in the first direction. In the first magnetic field generating unit MG1 shown in FIG. 2, from the viewpoint of ease of manufacturing, the magnetoresistive effect element 10a is located between the first magnetic body 31 and the second magnetic body 32 at a position shifted to one side of the Z1-Z2 direction along the stacking direction of the magnetoresistive effect element 10a, specifically, to the Z2 side.

[0029] A first wiring 21 extending in the Y1-Y2 direction is arranged on the Z1 side of the first magnetic body 31 in the Z1-Z2 direction, and a first wiring 22 extending in the Y1-Y2 direction is arranged on the Z2 side of the first magnetic body 31 in the Z1-Z2 direction. In this specification, the direction in which the first wirings 21 and 22 are arranged as viewed from the first magnetic body 31 and the second wirings 23 and 24 are arranged as viewed from the second magnetic body 32 is referred to as the "second direction." In the magnetic sensor 100 according to this embodiment shown in FIG. 2 and other figures, the second direction is the Z1-Z2 direction.

[0030] The first wirings 21 and 22 are configured so that, when energized, the direction of current flowing through the first wiring 21 is opposite to the direction of current flowing through the first wiring 22. In Fig. 2, the direction of current flowing through the first wiring 21 is the Y1-Y2 direction (Y1 direction), and the direction of current flowing through the first wiring 22 is the Y2-Y1-Y2 direction (Y2 direction). As a result, the induced magnetic fields generated from the first wiring 21 and the first wiring 22 are oriented in the same direction in the first magnetic body 31. There are no particular limitations on the material that makes up the first wirings 21 and 22 as long as they are conductive, and a material based on a non-magnetic element such as copper or aluminum is preferred.

[0031] A second wiring 23 extending in the Y1-Y2 direction is arranged on the Z1 side of the second magnetic body 32 in the Z1-Z2 direction (second direction), and a second wiring 24 extending in the Y1-Y2 direction is arranged on the Z2 side of the second magnetic body 32 in the Z1-Z2 direction (second direction). The second wirings 23 and 24 are set so that the direction of the induced magnetic field generated in the second magnetic body 32 by energizing them is equal to the direction of the induced magnetic field generated in the first magnetic body 31 by energizing the first wirings 21 and 22. In FIG. 2 , the direction of the current flowing in the second wiring 23 is equal to the direction of the current flowing in the first wiring 21, and the direction of the current flowing in the second wiring 24 is equal to the direction of the current flowing in the first wiring 22. The material constituting the second wirings 23 and 24 is not particularly limited as long as it is a conductor, and it is preferable that the material be the same as the material constituting the first wirings 21 and 22 from the viewpoints of improving controllability of the magnetic field applied to the magnetoresistive effect element 10a and improving ease of manufacture.

[0032] The first magnetic field convergence unit 41 extending in the Y1-Y2 direction is disposed on the Z1 side of the first wiring 21 in the Z1-Z2 direction (second direction). That is, the first magnetic field convergence unit 41 is provided on the side of the first wiring 21 opposite to the side facing the first magnetic body 31. The first magnetic field convergence unit 42 extending in the Y1-Y2 direction is disposed on the Z2 side of the first wiring 22 in the Z1-Z2 direction (second direction). That is, the first magnetic field convergence unit 42 is provided on the side of the first wiring 22 opposite to the side facing the first magnetic body 31. The first magnetic field convergence units 41, 42 suppress the divergence of the induced magnetic field generated by passing current through the first wirings 21, 22 on the side opposite to the side facing the first magnetic body 31 in the Z1-Z2 direction (second direction), thereby increasing the magnetic flux density flowing through the first magnetic body 31.

[0033] The second magnetic field convergence portion 43 extending in the Y1-Y2 direction is disposed on the Z1 side of the second wiring 23 in the Z1-Z2 direction (second direction). That is, the second magnetic field convergence portion 43 is provided on the side of the second wiring 23 opposite to the side facing the second magnetic body 32. The second magnetic field convergence portion 44 extending in the Y1-Y2 direction is disposed on the Z2 side of the second wiring 24 in the Z1-Z2 direction (second direction). That is, the second magnetic field convergence portion 44 is provided on the side of the second wiring 24 opposite to the side facing the second magnetic body 32. The second magnetic field convergence portions 43, 44 suppress divergence of the induced magnetic field generated by passing current through the second wirings 23, 24 on the side opposite to the side facing the second magnetic body 32 in the Z1-Z2 direction (second direction), thereby increasing the magnetic flux density flowing through the second magnetic body 32.

[0034] The insulating portion 50 may be made of any material and have any thickness as long as it can prevent current flowing through the wiring (first wirings 21, 22, second wirings 23, 24) from flowing to the first magnetic body 31 and the second magnetic body 32. The insulating portion 50 is preferably a diffusion suppression portion that suppresses interdiffusion between the elements constituting the wiring (first wirings 21, 22, second wirings 23, 24) and the elements constituting the first magnetic body 31 and the second magnetic body 32. When the insulating portion 50 suppresses interdiffusion between the wiring (first wirings 21, 22, second wirings 23, 24) and the first magnetic body 31 and the second magnetic body 32, the compositions of the two are less likely to change over time, thereby improving the quality stability (functional stability) of the magnetic sensor 100. From the perspective of properly functioning as a diffusion suppression portion, specific examples of materials constituting the insulating portion 50 include oxide-based materials such as silica (SiO) and alumina (AlO), and nitride-based materials such as silicon nitride (SiN) and aluminum nitride (AlN).

[0035] 3 is a diagram illustrating the induced magnetic field generated by passing a current through the wiring, and specifically, it is a diagram in which the direction of the magnetic flux of the induced magnetic field generated by passing a current through the first wirings 21 and 22 and the second wirings 23 and 24 is added to FIG. 2. The magnetic flux FL1 of the induced magnetic field generated by passing a current through the first wirings 21 and the second wirings 23 toward the Y1 side in the Y1-Y2 direction flows inside the first magnetic body 31 toward the X1 side in the X1-X2 direction and is radiated toward the insulating part 50 from the end of the first magnetic body 31 on the X1 side in the X1-X2 direction. However, because the second magnetic body 32 is located on the X1 side of the first magnetic body 31 in the X1-X2 direction, the magnetic flux FL1 is converged at the end of the second magnetic body 32 on the X2 side in the X1-X2 direction and then flows inside the second magnetic body 32 toward the X1 side in the X1-X2 direction.

[0036] The magnetic flux radiated from the end of the second magnetic body 32 on the X1 side in the X1-X2 direction to the insulating part 50 travels around the second wiring 23 in the XZ plane, reaches the second magnetic field convergence part 43 located on the Z1 side in the Z1-Z2 direction of the second wiring 23, passes through the inside of it, and reaches the end of the second wiring 23 on the X2 side in the X1-X2 direction. The magnetic flux FL1 radiated from the end of the second wiring 23 on the X2 side in the X1-X2 direction to the X2 side in the X1-X2 direction converges to the first magnetic field convergence part 41 located on the X2 side in the X1-X2 direction of the second magnetic field convergence part 43, and therefore divergence of the magnetic flux FL1 toward the Z2 side in the Z1-Z2 direction of the first magnetic field convergence part 41 and the second magnetic field convergence part 43 is appropriately suppressed. The magnetic flux FL1 that travels through the first magnetic field convergence portion 41 toward the X2 side in the X1-X2 direction is emitted from the end portion of the first magnetic field convergence portion 41 on the X2 side in the X1-X2 direction, travels around the second wiring 23 within the XZ plane, and reaches the end portion of the first magnetic body 31 on the X2 side in the X1-X2 direction.

[0037] Thus, the magnetic flux FL1 forms a magnetic circuit that passes from the first magnetic body 31 through the insulating part 50, the second magnetic body 32, the insulating part 50, the second magnetic field converger 43, the insulating part 50 and the first magnetic field converger 41, and returns to the first magnetic body 31. Since the magnetoresistive effect element 10a is disposed in the insulating part 50 between the second magnetic field converger 43 and the first magnetic field converger 41, a magnetic field is applied to the magnetoresistive effect element 10a along the sensitivity axis direction in the first direction (X1-X2 direction).

[0038] Similarly, magnetic flux FL2 of an induced magnetic field generated by current flowing through first wiring 22 and second wiring 24 toward the Y2 side in the Y1-Y2 direction forms a magnetic circuit that passes from first magnetic body 31 through insulating portion 50, second magnetic body 32, insulating portion 50, second magnetic field convergence portion 44, insulating portion 50, and first magnetic field convergence portion 42, and returns to first magnetic body 31. Since magnetoresistive effect element 10a is disposed in insulating portion 50 between second magnetic field convergence portion 43 and first magnetic field convergence portion 41, a magnetic field along the sensitivity axis direction in the first direction (X1-X2 direction) is applied to magnetoresistive effect element 10a.

[0039] The positional relationship between the first wirings 21, 22 and the first magnetic body 31, specifically the separation distance in the second direction (Z1-Z2 direction), is set so that an induced magnetic field generated by passing a current through the first wirings 21, 22 reaches the first magnetic body 31 appropriately, and magnetic fluxes FL1, FL2 are formed inside the first magnetic body 31. The positional relationship between the second wirings 23, 24 and the second magnetic body 32, specifically the separation distance in the second direction (Z1-Z2 direction), is also set so that an induced magnetic field generated by passing a current through the second wirings 23, 24 reaches the second magnetic body 32 appropriately, and magnetic fluxes FL1, FL2 are formed inside the second magnetic body 32.

[0040] Furthermore, the separation distance in the first direction (X1-X2 direction) between the first magnetic body 31 and the second magnetic body 32 is set so that an induced magnetic field generated when current is passed through the first wirings 21, 22 and the second wirings 23, 24 forms magnetic fluxes FL1, FL2 that penetrate the insulating part 50 located between the first magnetic body 31 and the second magnetic body 32 along the first direction (X1-X2 direction). In one example, the separation distance in the first direction between the first magnetic body 31 and the second magnetic body 32 is set to a distance that allows the induced magnetic field generated in the first wirings 21, 22 when current is passed through to reach the second magnetic body 32. As an example of a specific numerical range, since the magnetic flux density (unit: T) of the bias magnetic field applied to the magnetoresistive effect element 10a based on passing current through the first wiring 21, 22 and the second wiring 23, 24 is on the order of 0.1 millimeters to 10 millimeters, the separation distance in the first direction between the first magnetic body 31 and the second magnetic body 32 can be approximately 0.1 μm to 10 μm.

[0041] By forming the first magnetic field generating unit MG1 and the second magnetic field generating unit MG2 in this manner, the bias magnetic field generated by passing current through the wiring (first wirings 21, 22, second wirings 23, 24) can be efficiently applied to the magnetoresistive effect element 10a, and the effects of noise can be stably reduced.

[0042] FIG. 4 is a cross-sectional view illustrating the structure of a magnetic sensor according to another embodiment of the present invention. In the first magnetic field generating unit MG1a of the magnetic sensor shown in FIG. 4, the first wirings 21 and 22 are solenoid coils that surround the first magnetic body 31 with their winding axes along the first direction (X1-X2 direction), and the second wirings 23 and 24 are solenoid coils that surround the second magnetic body 32 with their winding axes also along the first direction (X1-X2 direction). Therefore, the first wirings 21 and 22 and the second wirings 23 and 24 each have a portion that extends along the Z1-Z2 direction. The solenoid coils that constitute the first wirings 21 and 22 and the second wirings 23 and 24 are wound so as to generate magnetic fluxes in the same direction in the first direction (specifically, toward the X1 side in the X1-X2 direction).

[0043] FIG. 5 is a cross-sectional view illustrating the structure of a modified example (part 1) of a magnetic sensor according to another embodiment of the present invention. In contrast to the first magnetic field generation unit MG1a shown in FIG. 4, the first magnetic field generation unit MG1b of the magnetic sensor shown in FIG. 5 does not include the first magnetic field convergence units 41, 42 and the second magnetic field convergence units 43, 44. Therefore, the magnetic sensor 100 including the first magnetic field generation unit MG1b is more productive since it does not include the magnetic field convergence units. In the first magnetic field generation unit MG1b having such a configuration, the induced magnetic field generated when current is applied to the first wirings 21, 22 and the second wirings 23, 24 tends to diverge relatively more on the Z1 side of the first wirings 21 and the second wirings 23 in the Z1-Z2 direction and relatively more on the Z2 side of the first wirings 22 and the second wirings 24 in the Z1-Z2 direction. Therefore, in the first magnetic field generating unit MG1b, when the amount of current flowing through the first wirings 21, 22 and the second wirings 23, 24 is equal, the bias magnetic field applied to the magnetoresistance effect element 10a tends to be relatively lower compared to the first magnetic field generating unit MG1a.

[0044] Fig. 6 is a cross-sectional view illustrating the structure of a modified example (part 2) of the magnetic sensor according to another embodiment of the present invention. In the first magnetic field generating unit MG1c of the magnetic sensor shown in Fig. 6, compared to the first magnetic field generating unit MG1a shown in Fig. 4, the first magnetic field convergence unit 41 and the second magnetic field convergence unit 43 are continuous in the first direction to form a first continuous magnetic field convergence unit 45, and the first magnetic field convergence unit 42 and the second magnetic field convergence unit 44 are continuous in the first direction to form a second continuous magnetic field convergence unit 46.

[0045] In the first magnetic field generation unit MG1c having such a configuration, the induced magnetic field generated when current is passed through the first wirings 21, 22 and the second wirings 23, 24 is relatively less likely to diverge on the Z1 side of the first wirings 21, 22 and the second wirings 23, 24 in the Z1-Z2 direction (second direction), and is relatively less likely to diverge on the Z2 side of the first wirings 21, 22 and the second wirings 23, 24 in the Z1-Z2 direction (second direction). Therefore, in the first magnetic field generation unit MG1c, compared to the first magnetic field generation unit MG1a, when the amount of current passed through the first wirings 21, 22 and the second wirings 23, 24 is equal, the bias magnetic field applied to the magnetoresistive effect element 10a tends to be relatively high.

[0046] On the other hand, because ferromagnetic materials are located on both sides of the magnetoresistive effect element 10a in the Z1-Z2 direction (second direction), the first continuous magnetic field convergence unit 45 and the second continuous magnetic field convergence unit 46 have a stronger function as a shield against external magnetic fields than the first magnetic field convergence units 41, 42 and the second magnetic field convergence units 43, 44. For this reason, the magnetic sensor 100 including the first magnetic field generation unit MG1c tends to have lower sensitivity to external magnetic fields than the magnetic sensor 100 including the first magnetic field generation unit MG1a. By having such a configuration, the magnetic sensor 100 including the first magnetic field generation unit MG1c can expand the measurement range of external magnetic fields compared to the magnetic sensor 100 including the first magnetic field generation unit MG1a, even though the sensitivity of the magnetoresistive effect element 10a is the same, and is advantageous when the strength of the external magnetic field to be measured is high.

[0047] FIG. 7 is a cross-sectional view illustrating the structure of a third modified example of a magnetic sensor according to another embodiment of the present invention. FIG. 8 is a cross-sectional view illustrating the structure of a fourth modified example of a magnetic sensor according to another embodiment of the present invention. As shown in FIGS. 7 and 8 , a magnetic field convergence portion may be provided for each wiring. In FIG. 7 , the first magnetic field convergence portion 471 is arranged on the Z1 side of the first wiring 21 in the Z1-Z2 direction (second direction) via an individual insulating portion 51. The individual insulating portion 51 may be made of the same material as the insulating portion 50 or may be made of the same material as the insulating portion 50. The first magnetic field convergence portion 472 is arranged on the Z2 side of the first wiring 22 in the Z1-Z2 direction (second direction) via an individual insulating portion 51. Similarly, the second magnetic field convergence portion 481 is arranged on the Z1 side of the second wiring 23 in the Z1-Z2 direction (second direction) via an individual insulating portion 51, and the second magnetic field convergence portion 482 is arranged on the Z2 side of the second wiring 24 in the Z1-Z2 direction (second direction) via an individual insulating portion 51.

[0048] 8 , the first magnetic field convergence portions 471, 472 and the second magnetic field convergence portions 481, 482 may extend so as to cover the surfaces facing the first direction (X1-X2 direction) of the first wirings 21, 22 and the second wirings 23, 24. Even in this case, individual insulating portions 51 are preferably provided between the first magnetic field convergence portions 471, 472 and the first wirings 21, 22, and between the second magnetic field convergence portions 481, 482 and the second wirings 23, 24.

[0049] 9 is a cross-sectional view illustrating the structure of a magnetic sensor according to the prior art. The first magnetic field generating unit MG1x comprises a single wiring 27 provided on the Z2 side of the magnetoresistive element 10a in the Z1-Z2 direction, and an insulating part 50 disposed between the magnetoresistive element 10a and the single wiring 27.

[0050] A simulation was performed on the magnetic sensor 100 including a magnetic field generating unit having a shape based on the first magnetic field generating units MG1a, MG1b, MG1c, and MG1x. The first wirings 21 and 22, the second wirings 23 and 24, and the single wiring 27 were all made of copper, and the first magnetic body 31, the second magnetic body 32, and the magnetic field convergence units (first magnetic field convergence units 41 and 42, second magnetic field convergence units 43 and 44, first continuous magnetic field convergence unit 45, and second continuous magnetic field convergence unit 46) were all made of permalloy.

[0051] The magnetoresistive effect element 10a is equidistant from the first magnetic body 31 and the second magnetic body 32 in the first direction, and the magnetoresistive effect element 10 is disposed so that the surface of the magnetoresistive effect element 10 on the Z1 side in the Z1-Z2 direction (second direction) is flush with the surfaces of the first magnetic body 31 and the second magnetic body 32 on the Z2 side in the Z1-Z2 direction (second direction). Other dimensions are set as follows. In the following description, the Y1-Y2 direction is referred to as the third direction.

[0052] Shape of the magnetoresistance effect element 10: cube of 1 μm in the first direction × 80 μm in the third direction Shape of each of the first magnetic body 31 and the second magnetic body 32: cube of 16 μm in the first direction × 80 μm in the third direction × 2 μm in the second direction First wiring 21, 22: three copper wires (pitch of 3 μm in the first direction) of 2 μm in the first direction × 80 μm in the third direction × 1.5 μm in the second direction, arranged on the X2 side from a position shifted 4 μm toward the X2 side from the X1-side end of the first magnetic body 31 in the X1-X2 direction (first direction) Second wiring 23, 24: three copper wires (pitch 3 μm in the first direction) of 2 μm in the first direction × 80 μm in the third direction × 1.5 μm in the second direction, arranged on the X1 side from a position shifted 4 μm toward the X1 side from the X2 side end of the second magnetic body 32 in the X1-X2 direction (first direction). Shapes of the first magnetic field convergence portions 41, 42 and the second magnetic field convergence portions 43, 44 in the first magnetic field generation unit MG1a: cubes of 16 μm in the first direction × 80 μm in the third direction × 0.5 μm in the second direction. Shapes of the first continuous magnetic field convergence portion 45 and the second continuous magnetic field convergence portion 46 in the first magnetic field generation unit MG1c: cubes of 34 μm in the first direction × 80 μm in the third direction × 0.5 μm in the second direction. Separation distance in the first direction between the first magnetic body 31 and the second magnetic body 32: 2 μm. - Separation distance in the second direction between the magnetic bodies (first magnetic body 31, second magnetic body 32) and the wirings (first wirings 21, 22, second wirings 23, 24): 0.25 μm - Separation distance in the second direction between the magnetic field convergence portions (first magnetic field convergence portions 41, 42, second magnetic field convergence portions 43, 44, first continuous magnetic field convergence portion 45, second continuous magnetic field convergence portion 46) and the wirings (first wirings 21, 22, second wirings 23, 24): 0.25 μm - Single wiring 27 in first magnetic field generation unit MG1x: copper wire of 2 μm in the first direction × 80 μm in the third direction × 1.5 μm in the second direction - Separation distance in the second direction between the single wiring 27 in first magnetic field generation unit MG1x and the magnetoresistance effect element 10a: 0.25 μm

[0053] The bias magnetic field Bb was determined when a current amount that generated an induced magnetic field (bias magnetic field Bb) measured as 0.16 mT in the magnetoresistive element 10a by passing current through the single wire 27 of the first magnetic field generation unit MG1x was applied to the first wires 21, 22 and the second wires 23, 24 of the first magnetic field generation units MG1a to MG1c. Furthermore, when an external magnetic field Bo measured as 1.00 mT in the magnetoresistive element 10a of the first magnetic field generation unit MG1x was applied to the first magnetic field generation units MG1a to MG1c, the external magnetic field Bo measured by each of the magnetoresistive elements 10a of the first magnetic field generation units MG1a to MG1c was determined. The simulation results are shown in Table 1.

[0054]

[0055] Although the first magnetic field generating unit MG1b does not have a magnetic field converging unit, the magnetic sensor 100 according to this embodiment is subjected to a bias magnetic field Bb that is about four times stronger than that of the first magnetic field generating unit MG1x of the magnetic sensor according to the prior art, and it was confirmed that the first magnetic field generating unit MG1b, which includes the magnetic bodies (first magnetic body 31 and second magnetic body 32), has a good function of amplifying the bias magnetic field Bb. Furthermore, when compared with the external magnetic field Bo, the magnetoresistive effect element 10a detected a value that was three times higher in the first magnetic field generating unit MG1b than in the first magnetic field generating unit MG1x, and it was also confirmed that the magnetic bodies (first magnetic body 31 and second magnetic body 32) function as a yoke for the external magnetic field Bo.

[0056] In comparison with the first magnetic field generation unit MG1b, the first magnetic field generation unit MG1a, which has the first magnetic field convergent units 41, 42 and the second magnetic field convergent units 43, 44, detected a bias magnetic field Bb that was approximately 40% higher than the first magnetic field generation unit MG1b, confirming that the amplification function of the bias magnetic field Bb in the first magnetic field generation unit MG1a is higher than that of the first magnetic field generation unit MG1b. The external magnetic field Bo was detected at approximately 15% of the strength of the first magnetic field generation unit MG1a compared to the first magnetic field generation unit MG1b. In comparison with the first magnetic field generation unit MG1b, it is believed that the first magnetic field convergent units 41, 42 and the second magnetic field convergent units 43, 44 functioned as a shield against the external magnetic field Bo.

[0057] In the first magnetic field generating unit MG1c, which has a structure in which the magnetic field converging portion is continuous in the first direction compared to the first magnetic field generating unit MG1a, a bias magnetic field Bb approximately 40% higher than that of the first magnetic field generating unit MG1a was detected, confirming that the first magnetic field generating unit MG1c has an even higher bias magnetic field Bb amplification function than the first magnetic field generating unit MG1a. The external magnetic field Bo detected in the first magnetic field generating unit MG1c was approximately 15% lower than that of the first magnetic field generating unit MG1a. The first continuous magnetic field converging portion 45 and the second continuous magnetic field converging portion 46, which are continuous in the first direction, are thought to function as a powerful shield against the external magnetic field Bo because ferromagnetic materials are present so as to cover both sides of the magnetoresistive effect element 10a in the Z1-Z2 direction (second direction).

[0058] The simulation results are shown in Figures 10 to 13. Figure 10 shows the simulation results of the magnetic field generated by the first magnetic field generation unit MG1x, Figure 11 shows the simulation results of the magnetic field generated by the first magnetic field generation unit MG1b, Figure 12 shows the simulation results of the magnetic field generated by the first magnetic field generation unit MG1a, and Figure 13 shows the simulation results of the magnetic field generated by the first magnetic field generation unit MG1c.

[0059] 10, in the first magnetic field generating unit MG1x of the magnetic sensor according to the conventional technology, a magnetic field is generated that circulates concentrically around the single wiring 27. Therefore, the induced magnetic field generated by passing a current through the single wiring 27 passes through the insulating portion 50 and is applied directly to the magnetoresistive effect element 10a.

[0060] 11 , in the first magnetic field generating unit MG1b of the magnetic sensor 100 according to one example of this embodiment, the induced magnetic field generated by passing current through the first wirings 21 and 22 and the induced magnetic field generated by passing current through the second wirings 23 and 24 are amplified by passing through the first magnetic body 31 and the second magnetic body 32, which have a higher relative permeability than the insulating unit 50, and are applied to the magnetoresistance effect element 10a located between the first magnetic body 31 and the second magnetic body 32. On the Z1 side of the first wirings 21 and 22 and the second wirings 23 and 24 in the Z1-Z2 direction (second direction) and on the Z2 side of the first wirings 21, 22 and the second wirings 23 and 24 in the Z1-Z2 direction (second direction), the induced magnetic field passes through the insulating unit 50, as in the case of the first magnetic field generating unit MG1x.

[0061] 12 , in the first magnetic field generating unit MG1a of the magnetic sensor 100 according to one example of this embodiment, the induced magnetic field generated by passing current through the first wirings 21 and 22 and the induced magnetic field generated by passing current through the second wirings 23 and 24 are amplified by passing through the first magnetic body 31 and the second magnetic body 32, which have a higher relative permeability than the insulating unit 50, and are then applied to the magnetoresistive effect element 10a located between the first magnetic body 31 and the second magnetic body 32. The induced magnetic field passes through the first magnetic field convergence portion 41 and the second magnetic field convergence portion 43 on the Z1 side of the first wirings 21 and the second wirings 23 in the Z1-Z2 direction (second direction). The magnetic flux of the induced magnetic field is oriented between the first magnetic field convergence portion 41 and the second magnetic field convergence portion 43 so as to connect the first magnetic field convergence portion 41 and the second magnetic field convergence portion 43. The direction of the magnetic flux of the induced magnetic field is distributed on the Z1 side of the first magnetic field convergence part 41 and the second magnetic field convergence part 43 in the Z1-Z2 direction (second direction) so as to circle around the center between the first magnetic field convergence part 41 and the second magnetic field convergence part 43. From this distribution, it can be understood that the space between the first magnetic field convergence part 41 and the second magnetic field convergence part 43 functions like a magnetic gap in the magnetic circuit of the induced magnetic field.

[0062] Furthermore, the induced magnetic field passes through the first magnetic field convergence portion 42 and the second magnetic field convergence portion 44 on the Z2 side of the first wiring 22 and the second wiring 24 in the Z1-Z2 direction (second direction). The direction of the magnetic flux of the induced magnetic field is distributed between the first magnetic field convergence portion 42 and the second magnetic field convergence portion 44 so as to connect the first magnetic field convergence portion 42 and the second magnetic field convergence portion 44. The direction of the magnetic flux of the induced magnetic field is distributed on the Z2 side of the first magnetic field convergence portion 42 and the second magnetic field convergence portion 44 in the Z1-Z2 direction (second direction) so as to circle around the space between the first magnetic field convergence portion 42 and the second magnetic field convergence portion 44. From this distribution, it can be understood that the space between the first magnetic field convergence portion 42 and the second magnetic field convergence portion 44 functions like a magnetic gap in the magnetic circuit of the induced magnetic field.

[0063] 13, the first magnetic field generation unit MG1c of the magnetic sensor 100 according to one example of this embodiment differs from the first magnetic field generation unit MG1a shown in FIG. 12 in the distribution of magnetic flux at the outermost sides in the Z1-Z2 direction (second direction), specifically, on the Z1 side of the first continuous magnetic field convergence unit 45 in the Z1-Z2 direction (second direction) and on the Z2 side of the second continuous magnetic field convergence unit 46 in the Z1-Z2 direction (second direction). In particular, the first magnetic field generation unit MG1c does not have a portion that functions like a magnetic gap, as does the first magnetic field generation unit MG1a. Therefore, the magnetic flux is distributed in the X1-X2 direction (first direction) so as to connect both ends of the first continuous magnetic field convergence unit 45 in the X1-X2 direction, and the magnetic flux is distributed in the X1-X2 direction (first direction) so as to connect both ends of the second continuous magnetic field convergence unit 46 in the X1-X2 direction (first direction).

[0064] 11 to 13, we will further compare the magnetic flux in a region (first region R1, shown by dotted lines in FIGS. 11 to 13) on the X2 side of the second wiring 23 in the X1-X2 direction (first direction) and the Z1 side of the second magnetic body 32 in the Z1-Z2 direction (second direction). In the first magnetic field generating unit MG1b shown in FIG. 11, the induced magnetic field generated by the second wiring 23 circulates around the second wiring 23 on the Z1 side in the Z1-Z2 direction (second direction). Therefore, in the first region R1, the magnetic flux faces the Z2 side in the Z1-Z2 direction (second direction) and toward the second magnetic body 32. Therefore, the magnetic flux that passes through the first region R1 and enters the second magnetic body 32 flows through the second magnetic body 32 in the X1-X2 direction (first direction) and X1 direction, and is not applied to the magnetoresistance effect element 10a.

[0065] 12, the induced magnetic field generated from the second wiring 23 passes through the second magnetic field convergence portion 43 on the Z1 side in the Z1-Z2 direction (second direction), so most of the magnetic flux emitted from the second magnetic field convergence portion 43 heads toward the first magnetic field convergence portion 41, and the magnetic flux facing the Z2 side in the Z1-Z2 direction (second direction) in the first region R1 is less than in the case of the first magnetic field generation portion MG1b. Therefore, in the first magnetic field generation portion MG1a, the component of the induced magnetic field generated from the second wiring 23 that is applied to the magnetoresistance effect element 10a is greater than in the first magnetic field generation portion MG1b.

[0066] 13, the first magnetic field generation unit MG1c has a configuration in which the second magnetic field convergence unit 43 and the first magnetic field convergence unit 41 are magnetically coupled via a magnetic gap, whereas the first magnetic field generation unit MG1a has a configuration in which a first continuous magnetic field convergence unit 45 without a magnetic gap is provided, and therefore, less magnetic flux faces the Z1-Z2 direction (second direction) Z2 side in the first region R1 than in the case of the first magnetic field generation unit MG1a. Therefore, in the first magnetic field generation unit MG1c, most of the induced magnetic field generated from the second wiring 23 passes through the first continuous magnetic field convergence unit 45 and reaches the first magnetic body 31, and the component applied to the magnetoresistive effect element 10a is greater than in the first magnetic field generation unit MG1a.

[0067] The above-described embodiments are provided to facilitate understanding of the present invention and are not intended to limit the present invention. Therefore, the elements disclosed in the above embodiments are intended to encompass all design modifications and equivalents that fall within the technical scope of the present invention. In the first magnetic field generator MG1a and other components according to the above embodiments, the first wirings 21 and 22 are provided corresponding to the first magnetic body 31, and the second wirings 23 and 24 are provided corresponding to the second magnetic body 32. However, this is not limited to this. Wiring may be provided corresponding to only one of the first magnetic body 31 and the second magnetic body 32. For example, the first wirings 21 and 22 may be provided corresponding to the first magnetic body 31, and the second wirings 23 and 24 may not be provided. Furthermore, only one of the first wirings 21 and 22 may be provided. In these cases, when an induced magnetic field generated by energizing one or both of the first wirings 21 and 22 passes through the first magnetic body 31 and is emitted at the end of the first magnetic body 31 on the X1 side in the X1-X2 direction, the second magnetic body 32 performs a magnetization function that preferentially directs the emitted magnetic flux in the first direction (X1-X2 direction). As a result, the induced magnetic field has more components oriented in the sensitivity axis direction (first direction) of the magnetoresistive effect element 10a, thereby improving the detection sensitivity of the magnetoresistive effect element 10a. Alternatively, in the first magnetic field generator MG1a and the like according to the above-described embodiment, the stacking direction of the magnetoresistive effect element 10a is aligned with the second direction, but this is not limited thereto and may be aligned with a direction other than the second direction, for example, a third direction (Y1-Y2 direction).

[0068] 100: Magnetic sensor 10, 10a, 10b, 10c, 10d: Magnetoresistance effect element 11: Fixed magnetic layer 12: Free magnetic layer 13: Intermediate layer 21, 22: First wiring 23, 24: Second wiring 27: Single wiring 31: First magnetic body 32: Second magnetic body 41, 42, 471, 472: First magnetic field convergence section 43, 44, 481, 482: Second magnetic field convergence section 45: First continuous magnetic field convergence section 46: Second continuous magnetic field convergence section 50: Insulation section FL1, FL2: Magnetic flux GND: Ground terminal H: Detection magnetic field MG1, MG1a, MG1b, MG1c, MG1x: First magnetic field generation section MG2: Second magnetic field generation section R1 : 1st area V1, V2 : Output terminal Vdd : Power supply terminal

Claims

1. A magnetic sensor comprising: a first magnetic body and a second magnetic body arranged at a distance in a first direction; a magnetoresistance effect element having a sensitivity axis along the first direction and positioned between the first magnetic body and the second magnetic body in the first direction; a first wiring positioned on a second direction side of the first magnetic body perpendicular to the first direction, the first wiring causing a magnetic flux passing through the first magnetic body to generate an induced magnetic field having a component in the first direction when current is applied; and an insulating portion positioned between the first wiring and the first magnetic body.

2. A magnetic sensor as described in claim 1, comprising a second wiring arranged on the second direction side of the second magnetic body via the insulating portion, and when current is passed through the second magnetic body, the second wiring generates an induced magnetic field having a component in the first direction, and the orientation of the first direction component of the magnetic flux passing through the first magnetic body based on the induced magnetic field generated by passing current through the first wiring is equal to the orientation of the first direction component of the magnetic flux passing through the second magnetic body based on the induced magnetic field generated in the second magnetic body by passing current through the second wiring.

3. The magnetic sensor according to claim 1 or 2, wherein the insulating portion includes a diffusion suppression portion.

4. A magnetic sensor according to claim 1 or 2, wherein the first wiring is provided on both sides of the first magnetic body in the second direction.

5. The magnetic sensor according to claim 2, wherein the second wiring is provided on both sides of the second magnetic body in the second direction.

6. A magnetic sensor as described in claim 1 or claim 2, further comprising a first magnetic field convergence portion including a ferromagnetic material, the first magnetic field convergence portion being provided on the side of the first wiring opposite the side facing the first magnetic material.

7. The magnetic sensor according to claim 2, further comprising a second magnetic field convergence portion including a ferromagnetic material, the second magnetic field convergence portion being provided on the side of the second wiring opposite the side facing the second magnetic material.

8. The magnetic sensor according to claim 7, further comprising a first magnetic field converging portion including a ferromagnetic material, the first magnetic field converging portion being provided on the side of the first wiring opposite to the side facing the first magnetic material.

9. The magnetic sensor according to claim 8, wherein, when viewed in the second direction, the magnetoresistance effect element does not overlap either the first magnetic field converging portion or the second magnetic field converging portion.

10. The magnetic sensor according to claim 8, wherein said first magnetic field converging portion and said second magnetic field converging portion are arranged adjacent to each other in said first direction.

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