magnetic sensor

Abstract

To achieve a magnetic sensor that can prevent a reduction in the sensitivity of a magnetoresistance effect element.SOLUTION: A magnetic sensor 1 comprises: MR elements 50; a ferromagnetic layer 72 that is arranged to overlap the MR elements 50 when seen from a first direction D1; insulating layers 32 that are arranged on both sides of the MR elements 50 in a second direction D2; and an antiferromagnetic layer 74 that is arranged on the MR elements 50, ferromagnetic layer 72, and insulating layer 32. The antiferromagnetic layer 74 includes an antiferromagnetic part 74a opposite to the ferromagnetic layer 72, and a non-opposite portion 74b opposite to the MR elements 50 and insulating layer 32 but not opposite to the ferromagnetic layer 72. Any magnetic layers are not present between the MR elements 50 and antiferromagnetic layer 74.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a magnetic sensor configured so that a bias magnetic field can be applied to a magnetoresistive element. [Background technology]

[0002] In recent years, magnetic sensors have been used in a variety of applications. A known magnetic sensor uses a spin-valve magnetoresistive element provided on a substrate. The spin-valve magnetoresistive element has a fixed magnetization layer with a fixed magnetization direction, a free layer with a magnetization direction that can change depending on the direction of the target magnetic field, and a gap layer disposed between the fixed magnetization layer and the free layer.

[0003] Some magnetic sensors are equipped with a means for applying a bias magnetic field to the magnetoresistive element. The bias magnetic field is used, for example, to make the magnetoresistive element respond linearly to changes in the strength of the target magnetic field. In magnetic sensors using spin-valve magnetoresistive elements, the bias magnetic field is also used to make the free layer a single magnetic domain and to orient the magnetization direction of the free layer in a fixed direction when there is no target magnetic field.

[0004] A known means for generating a bias magnetic field is a magnetic field generator formed by stacking an antiferromagnetic layer and a ferromagnetic layer. Patent documents 1 and 2 disclose a magnetic sensor including a magnetoresistive element and two magnetic field generators arranged to sandwich the magnetoresistive element. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-125020 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-176911 Summary of the Invention [Problem to be solved by the invention]

[0006] In order to increase the strength of the bias magnetic field applied to the magnetoresistive element, it is preferable to reduce the distance between the magnetoresistive element and the magnetic field generator and increase the size of the magnetic field generator. For example, it is possible to increase the strength of the bias magnetic field applied to the magnetoresistive element by forming an insulating layer around the entire periphery of the magnetoresistive element and then forming a magnetic field generator on top of the magnetoresistive element and the insulating layer so as to cover the entire magnetoresistive element. However, this would cause the magnetic layer included in the magnetic field generator to function as a shield, resulting in a problem of reduced sensitivity of the magnetoresistive element.

[0007] The present invention has been made in view of the above problems, and an object of the present invention is to provide a magnetic sensor capable of suppressing a decrease in the sensitivity of the magnetoresistive effect element. [Means for solving the problem]

[0008] The magnetic sensor of the present invention includes at least one magnetoresistive element including a plurality of stacked magnetic films; a first ferromagnetic layer made of a ferromagnetic material and arranged so as to overlap the at least one magnetoresistive element when viewed in a first direction perpendicular to the stacking direction of the magnetic films; insulating layers made of an insulating material and arranged on both sides of the at least one magnetoresistive element in a second direction perpendicular to both the stacking direction and the first direction; and an antiferromagnetic layer arranged on the at least one magnetoresistive element, the first ferromagnetic layer, and the insulating layer. The antiferromagnetic layer includes a first antiferromagnetic portion facing the first ferromagnetic layer and a non-facing portion facing the at least one magnetoresistive element and the insulating layer but not facing the first ferromagnetic layer. No magnetic layer is present between the at least one magnetoresistive element and the antiferromagnetic layer. [Effects of the Invention]

[0009] In the magnetic sensor of the present invention, an antiferromagnetic layer is disposed on at least one magnetoresistive element, a first ferromagnetic layer, and an insulating layer. The antiferromagnetic layer includes a first antiferromagnetic portion facing the first ferromagnetic layer and a non-facing portion facing the at least one magnetoresistive element and the insulating layer but not facing the first ferromagnetic layer. No magnetic layer is present between the at least one magnetoresistive element and the antiferromagnetic layer. This makes it possible to suppress a decrease in the sensitivity of the magnetoresistive element. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view showing a magnetic sensor device including a magnetic sensor according to a first embodiment of the present invention. [Figure 2] FIG. 1 is a functional block diagram showing a configuration of a magnetic sensor device according to a first embodiment of the present invention. [Figure 3] 1 is a circuit diagram showing a circuit configuration of a magnetic sensor according to a first embodiment of the present invention. [Figure 4] FIG. 2 is a perspective view showing a part of a first detection circuit according to the first embodiment of the present invention. [Figure 5] FIG. 2 is a plan view showing a part of a first detection circuit according to the first embodiment of the present invention. [Figure 6] FIG. 3 is a plan view showing a part of a second detection circuit in the first embodiment of the present invention. [Figure 7] 1 is a plan view showing a main part of a magnetic sensor according to a first embodiment of the present invention. [Figure 8] 1 is a plan view showing a magnetoresistive element, a magnetic field generator, and an insulating layer according to a first embodiment of the present invention. [Figure 9] 9 is a cross-sectional view showing a part of a cross section taken along line 9-9 in FIG. 7. [Figure 10] 8 is a cross-sectional view showing a part of a cross section taken along line 10-10 in FIG. 7. [Figure 11] 10A and 10B are cross-sectional views showing a method for forming a magnetic field generator of a comparative example. [Figure 12]2A to 2C are cross-sectional views illustrating a method for forming a magnetic field generator according to the first embodiment of the present invention. [Figure 13] FIG. 2 is a plan view showing a main part of a first modified example of the magnetic sensor according to the first embodiment of the present invention. [Figure 14] FIG. 10 is a plan view showing a main part of a second modified example of the magnetic sensor according to the first embodiment of the present invention. [Figure 15] FIG. 10 is a plan view showing a main part of a third modified example of the magnetic sensor according to the first embodiment of the present invention. [Figure 16] FIG. 10 is a cross-sectional view showing a main part of a fourth modified example of the magnetic sensor according to the first embodiment of the present invention. [Figure 17] FIG. 10 is a cross-sectional view showing a main part of a fifth modified example of the magnetic sensor according to the first embodiment of the present invention. [Figure 18] FIG. 10 is a cross-sectional view showing a main part of a sixth modified example of the magnetic sensor according to the first embodiment of the present invention. [Figure 19] FIG. 13 is a cross-sectional view showing a main part of a seventh modified example of the magnetic sensor according to the first embodiment of the present invention. [Figure 20] FIG. 10 is a perspective view showing a magnetic sensor system including a magnetic sensor according to a second embodiment of the present invention. [Figure 21] FIG. 6 is a circuit diagram showing a circuit configuration of a magnetic sensor according to a second embodiment of the present invention. [Figure 22] FIG. 10 is a perspective view showing a part of a magnetic sensor according to a second embodiment of the present invention. [Figure 23] FIG. 10 is a plan view showing a part of a magnetic sensor according to a second embodiment of the present invention. [Figure 24] FIG. 10 is a side view showing a part of a magnetic sensor according to a second embodiment of the present invention. [Figure 25] FIG. 10 is a plan view showing a main part of a magnetic sensor according to a second embodiment of the present invention. [Figure 26] 26 is a cross-sectional view showing a part of the cross section at the position indicated by line 26-26 in FIG. 25. [Figure 27] 27 is a cross-sectional view showing a part of the cross section at the position indicated by line 27-27 in FIG. 25. [Figure 28] FIG. 10 is a plan view showing a main part of a magnetic sensor according to a third embodiment of the present invention. [Figure 29] 29 is a cross-sectional view showing a part of the cross section at the position indicated by line 29-29 in FIG. 28. [Figure 30] 29 is a cross-sectional view showing a part of the cross section at the position indicated by the line 30-30 in FIG. 28. DETAILED DESCRIPTION OF THE INVENTION

[0011] [First embodiment] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, the configuration of a magnetic sensor device including a magnetic sensor according to a first embodiment of the present invention will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a perspective view showing the magnetic sensor device according to this embodiment. Fig. 2 is a functional block diagram showing the configuration of the magnetic sensor device according to this embodiment.

[0012] The magnetic sensor device 100 of this embodiment includes a magnetic sensor 1 according to this embodiment and a processor 2. The magnetic sensor 1 is configured to detect a target magnetic field, which is a magnetic field to be detected by the magnetic sensor 1, and generate at least one detection signal. The magnetic sensor 1 may be a geomagnetic sensor that detects geomagnetism, a magnetic sensor for an angle sensor or magnetic encoder that detects a rotating magnetic field, or a magnetic sensor for a current sensor that detects a magnetic field generated by a current to be detected.

[0013] The processor 2 is configured to generate at least one detection value corresponding to the target magnetic field based on the at least one detection signal. The processor 2 is configured, for example, by an application specific integrated circuit (ASIC).

[0014] The magnetic sensor 1 and the processor 2 each have the form of a rectangular parallelepiped chip. The magnetic sensor 1 has an upper surface 1a and a lower surface 1b located opposite each other, and four side surfaces connecting the upper surface 1a and the lower surface 1b. The processor 2 has an upper surface 2a and a lower surface 2b located opposite each other, and four side surfaces connecting the upper surface 2a and the lower surface 2b. The magnetic sensor 1 is mounted on the upper surface 2a of the processor 2, with the lower surface 1b of the magnetic sensor 1 facing the upper surface 2a of the processor 2. The magnetic sensor 1 is bonded to the processor 2, for example, by adhesive.

[0015] Here, the X direction, Y direction, and Z direction are defined as shown in FIG. 1. The X direction, Y direction, and Z direction are perpendicular to one another. In this embodiment, the Z direction is a direction perpendicular to the top surface 1a of the magnetic sensor 1, and is a direction from the bottom surface 1b of the magnetic sensor 1 toward the top surface 1a. The direction opposite the X direction is the -X direction, the direction opposite the Y direction is the -Y direction, and the direction opposite the Z direction is the -Z direction.

[0016] Hereinafter, a position further in the Z direction than the reference position will be referred to as "above," and a position on the opposite side of "above" than the reference position will be referred to as "below." Furthermore, with regard to the components of the 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." Furthermore, the expression "when viewed from a specified direction (e.g., the Z direction)" means viewing the object from a position away from the specified direction or in one direction parallel to the specified direction.

[0017] The magnetic sensor 1 has a plurality of first pads (electrode pads) provided on the upper surface 1a. The processor 2 has a plurality of second pads (electrode pads) provided on the upper surface 2a. In the magnetic sensor 1, two corresponding pads of the plurality of first pads and the plurality of second pads are connected to each other by a bonding wire.

[0018] The magnetic sensor 1 includes a first detection circuit 10 and a second detection circuit 20. The first and second detection circuits 10, 20 are connected to the processor 2 via a plurality of first pads, a plurality of second pads, and a plurality of bonding wires.

[0019] Each of the first and second detection circuits 10 and 20 includes a plurality of magnetic detection elements. In this embodiment, the plurality of magnetic detection elements are particularly a plurality of magnetoresistive effect elements. Hereinafter, the magnetoresistive effect elements will be referred to as MR elements.

[0020] The first detection circuit 10 detects a component of the target magnetic field parallel to the X direction and generates at least one first detection signal corresponding to this component. The second detection circuit 20 detects a component of the target magnetic field parallel to the Y direction and generates at least one second detection signal corresponding to this component.

[0021] Next, the circuit configuration of the magnetic sensor 1 will be described with reference to Fig. 3. Fig. 3 is a circuit diagram showing the circuit configuration of the magnetic sensor 1.

[0022] The first detection circuit 10 includes four resistors R11, R12, R13, and R14, a power supply port V1, a ground port G1, and two output ports E11 and E12. The resistor R11 is provided between the power supply port V1 and the output port E11. The resistor R12 is provided between the output port E11 and the ground port G1. The resistor R13 is provided between the output port E12 and the ground port G1. The resistor R14 is provided between the power supply port V1 and the output port E12. A voltage or current of a predetermined magnitude is applied to the power supply port V1. The ground port G1 is connected to ground.

[0023] The second detection circuit 20 includes four resistors R21, R22, R23, and R24, a power supply port V2, a ground port G2, and two output ports E21 and E22. The resistor R21 is provided between the power supply port V2 and the output port E21. The resistor R22 is provided between the output port E21 and the ground port G2. The resistor R23 is provided between the output port E22 and the ground port G2. The resistor R24 ​​is provided between the power supply port V2 and the output port E22. A voltage or current of a predetermined magnitude is applied to the power supply port V2. The ground port G2 is connected to ground.

[0024] Next, the configuration of each of the first and second detection circuits 10, 20 will be described with reference to Figures 4 to 6. Figure 4 is a perspective view showing a portion of the first detection circuit 10. Figure 5 is a plan view showing a portion of the first detection circuit 10. Figure 6 is a plan view showing a portion of the second detection circuit 20.

[0025] The magnetic sensor 1 further includes a substrate 30. The magnetic sensor 1 is configured by forming a plurality of components other than the substrate 30 on the substrate 30. The first detection circuit 10 and the second detection circuit 20 are provided on the substrate 30. Each of the resistor units R11 to R14 includes a plurality of MR elements 50A. Each of the resistor units R21 to R24 includes a plurality of MR elements 50B.

[0026] Each of the resistor sections R11 to R14 further includes a plurality of lower electrodes 61 and a plurality of upper electrodes 62. As shown in FIGS. 4 and 5, each of the plurality of MR elements 50A has a shape that is elongated in a direction parallel to the Y direction. Each of the plurality of lower electrodes 61 electrically connects two adjacent MR elements 50A in a direction parallel to the X direction. Each of the plurality of upper electrodes 62 is disposed on two lower electrodes 61 and electrically connects two adjacent MR elements 50A. As a result, the plurality of MR elements 50A lined up in a line in a direction parallel to the X direction are connected in series.

[0027] Each of the resistor units R11 to R14 further includes a plurality of connection electrodes (not shown). In each of the resistor units R11 to R14, the plurality of connection electrodes electrically connect the plurality of lower electrodes 61 or the plurality of upper electrodes 62 so that a group of the plurality of MR elements 50A arranged in a row is connected in series. With this configuration, each of the resistor units R11 to R14 includes the plurality of MR elements 50A connected in series by the plurality of lower electrodes 61, the plurality of upper electrodes 62, and the plurality of connection electrodes.

[0028] The above description of the connection relationship of the plurality of MR elements 50A basically also applies to the plurality of MR elements 50B in each of the resistor units R21 to R24. As shown in Fig. 6, in each of the resistor units R21 to R24, each of the plurality of MR elements 50B has a shape that is elongated in a direction parallel to the X direction. If the plurality of MR elements 50A, X direction, and Y direction in the above description of the connection relationship of the plurality of MR elements 50A are replaced with the plurality of MR elements 50B, Y direction, and X direction, respectively, the description becomes the connection relationship of the plurality of MR elements 50B.

[0029] Each of the resistor sections R11 to R14 further includes a plurality of magnetic field generators 70A. The plurality of magnetic field generators 70A includes a plurality of pairs of magnetic field generators 70A, each consisting of two magnetic field generators 70A. The two magnetic field generators 70A are arranged at a predetermined interval in a direction parallel to the Y direction so as to sandwich one MR element 50A. The two magnetic field generators 70A are configured to apply a bias magnetic field to the one MR element 50A located between them. This bias magnetic field mainly includes a component parallel to the Y direction.

[0030] Each of the resistor sections R21 to R24 further includes a plurality of magnetic field generators 70B. The plurality of magnetic field generators 70B includes a plurality of pairs of magnetic field generators 70B, each consisting of two magnetic field generators 70B. The two magnetic field generators 70B are arranged at a predetermined interval in a direction parallel to the X direction so as to sandwich one MR element 50B. The two magnetic field generators 70B are configured to apply a bias magnetic field to the one MR element 50B located between them. This bias magnetic field mainly includes a component parallel to the X direction.

[0031] 4, each of the plurality of magnetic field generators 70A may be sandwiched between the lower electrode 61 and the upper electrode 62. Although not shown, each of the plurality of magnetic field generators 70B may be sandwiched between the lower electrode 61 and the upper electrode 62.

[0032] In this embodiment, each of the multiple MR elements 50A and the multiple MR elements 50B is a spin-valve MR element. This spin-valve MR element includes a magnetization pinned layer having a fixed magnetization direction, a free layer having a magnetization direction that can be changed depending on the direction of a target magnetic field, and a gap layer disposed between the magnetization pinned layer and the free layer. The spin-valve MR element may be a TMR (tunneling magnetoresistance) element or a GMR (giant magnetoresistance) element. In a TMR element, the gap layer is a tunnel barrier layer. In a GMR element, the gap layer is a nonmagnetic conductive layer. In a spin-valve MR element, the resistance value varies depending on the angle between the magnetization direction of the free layer and the magnetization direction of the magnetization pinned layer. When this angle is 0°, the resistance value is minimum, and when this angle is 180°, the resistance value is maximum. In each MR element, the free layer has shape anisotropy such that the easy axis of magnetization is perpendicular to the magnetization direction of the magnetization pinned layer.

[0033] The spin-valve MR element may further include an antiferromagnetic layer. The antiferromagnetic layer is made of an antiferromagnetic material and generates exchange coupling with the magnetization pinned layer to pin the magnetization direction of the magnetization pinned layer. The magnetization pinned layer may be a so-called self-pinned type pinned layer (synthetic ferri-pinned layer, SFP layer). The self-pinned type pinned layer has a synthetic 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. When the magnetization pinned layer is a self-pinned type pinned layer, the antiferromagnetic layer may be omitted.

[0034] Next, the magnetization direction of the magnetization pinned layer and the direction of the bias magnetic field will be described with reference to FIG. 3. In FIG. 3, multiple solid arrows drawn to overlap the resistor units R11 to R14 and R21 to R24 respectively represent the magnetization direction of the magnetization pinned layer in each of the resistor units R11 to R14 and R21 to R24. In the example shown in FIG. 3, the direction of the main component of magnetization of the magnetization pinned layer in each of the resistor units R11 and R13 is the X direction. The direction of the main component of magnetization of the magnetization pinned layer in each of the resistor units R12 and R14 is the −X direction. The free layer in each of the resistor units R11 to R14 has shape anisotropy in which the easy axis of magnetization is parallel to the Y direction.

[0035] The direction of the main component of magnetization of the magnetization fixed layer in each of the resistor units R21 and R23 is the Y direction. The direction of the main component of magnetization of the magnetization fixed layer in each of the resistor units R22 and R24 is the -Y direction. The free layer in each of the resistor units R21 to R24 has shape anisotropy such that the direction of the easy axis of magnetization is parallel to the X direction.

[0036] 3, the arrows labeled M11, M12, M13, and M14 indicate the directions of the main components of the bias magnetic fields generated by the multiple magnetic field generators 70A at the resistor units R11, R12, R13, and R14, respectively. The direction of the main component of the bias magnetic field at the resistor units R11 and R12 is the Y direction. The direction of the main component of the bias magnetic field at the resistor units R13 and R14 is the -Y direction.

[0037] 3, the multiple white arrows drawn to overlap the resistor units R11 to R14 respectively represent the magnetization direction of the free layer in each of the resistor units R11 to R14 when no target magnetic field is applied to the magnetic sensor 1. The direction of the main component of the magnetization of the free layer in each of the resistor units R11 and R12 is the Y direction, which is the same as the direction of the main component of the bias magnetic field in the resistor units R11 and R12. The direction of the main component of the magnetization of the free layer in each of the resistor units R13 and R14 is the -Y direction, which is the same as the direction of the main component of the bias magnetic field in the resistor units R13 and R14.

[0038] 3, the arrows labeled M21, M22, M23, and M24 indicate the directions of the main components of the bias magnetic fields generated by the multiple magnetic field generators 70B in the resistor units R21, R22, R23, and R24, respectively. The direction of the main component of the bias magnetic field in the resistor units R21 and R22 is the X direction. The direction of the main component of the bias magnetic field in the resistor units R23 and R24 is the -X direction.

[0039] 3, multiple open arrows drawn to overlap the resistor units R21 to R24 represent the magnetization direction of the free layer in each of the resistor units R21 to R24 when no target magnetic field is applied to the magnetic sensor 1. The direction of the main component of the magnetization of the free layer in each of the resistor units R21 and R22 is the X direction, which is the same as the direction of the main component of the bias magnetic field in the resistor units R21 and R22. The direction of the main component of the magnetization of the free layer in each of the resistor units R23 and R24 is the −X direction, which is the same as the direction of the main component of the bias magnetic field in the resistor units R23 and R24.

[0040] The direction of magnetization may be the same as the direction of the main component of magnetization described above, or may be slightly deviated from the direction of the main component of magnetization. Similarly, the direction of the bias magnetic field may be the same as the direction of the main component of the bias magnetic field described above, or may be slightly deviated from the direction of the main component of the bias magnetic field. In the following description, the direction of magnetization is assumed to be the same as the direction of the main component of magnetization, and the direction of the bias magnetic field is assumed to be the same as the direction of the main component of the bias magnetic field.

[0041] Next, the operation of the first and second detection circuits 10 and 20 will be described with reference to FIG. 3. In the first detection circuit 10, the potential at the connection point between the resistors R11 and R12, i.e., the potential at the output port E11, and the potential at the connection point between the resistors R13 and R14, i.e., the potential at the output port E12, change depending on the strength of the component of the target magnetic field parallel to the X-direction. The first detection circuit 10 may generate, as first detection signals, signals corresponding to the potential at the output port E11 and the potential at the output port E12. Alternatively, the first detection circuit 10 may generate, as the first detection signal, a signal corresponding to the potential difference between the output ports E11 and E12. In this case, the first detection circuit 10 may further include a differential amplifier (differential detector) that outputs, as the first detection signal, a signal corresponding to the potential difference between the output ports E11 and E12.

[0042] In the second detection circuit 20, the potential at the connection point of the resistor units R21 and R22, i.e., the potential at the output port E21, and the potential at the connection point of the resistor units R23 and R24, i.e., the potential at the output port E22, change depending on the strength of the component of the target magnetic field parallel to the Y direction. The second detection circuit 20 may generate, as the second detection signal, a signal corresponding to the potential at the output port E21 and a signal corresponding to the potential at the output port E22. Alternatively, the second detection circuit 20 may generate, as the second detection signal, a signal corresponding to the potential difference between the output ports E21 and E22. In this case, the second detection circuit 20 may further include a differential amplifier (differential detector) that outputs, as the second detection signal, a signal corresponding to the potential difference between the output ports E21 and E22.

[0043] Next, the configurations of the plurality of MR elements 50A, the plurality of MR elements 50B, the plurality of magnetic field generators 70A, and the plurality of magnetic field generators 70B will be described in detail with reference to Figs. 7 to 10. Fig. 7 is a plan view showing a main part of the magnetic sensor 1. Fig. 8 is a plan view showing the MR elements, the magnetic field generators, and the insulating layer. Fig. 9 is a cross-sectional view showing a part of the cross section indicated by line 9-9 in Fig. 7. Fig. 10 is a cross-sectional view showing a part of the cross section indicated by line 10-10 in Fig. 7.

[0044] 7 to 10, a first direction D1 and a second direction D2 are defined, each of which is perpendicular to the Z direction and perpendicular to each other. In the first detection circuit 10, the first direction D1 is parallel to the Y direction, and the second direction D2 is parallel to the X direction. In the second detection circuit 20, the first direction D1 is parallel to the X direction, and the second direction D2 is parallel to the Y direction.

[0045] Hereinafter, any one of the plurality of MR elements 50A and the plurality of MR elements 50B will be represented by the reference symbol 50, and any one of the plurality of magnetic field generators 70A and the plurality of magnetic field generators 70B will be represented by the reference symbol 70. The magnetic sensor 1 includes at least one MR element 50. In particular, in this embodiment, the magnetic sensor 1 includes a plurality of MR elements 50 as the at least one MR element 50.

[0046] Here, focusing on one MR element 50, the configuration of the MR element 50 and the magnetic field generator 70 will be described. The MR element 50 includes multiple magnetic films. The stacking direction of the multiple magnetic films is parallel to the Z direction. The multiple magnetic films include the aforementioned magnetization fixed layer 52 and free layer 54. Each of the multiple MR elements 50 further includes the aforementioned gap layer 53, buffer layer 51, and cap layer 55. As shown in FIGS. 9 and 10 , the buffer layer 51, magnetization fixed layer 52, gap layer 53, free layer 54, and cap layer 55 are stacked in this order in the Z direction. The buffer layer 51 and cap layer 55 are each formed of a nonmagnetic metal material such as Ru, Ta, Cu, or Cr.

[0047] The MR element 50 has an upper surface 50a located at an end in the Z direction, a lower surface 50b located at an end in the -Z direction, two side surfaces 50c located at both ends in the first direction D1, and two side surfaces 50d located at both ends in the second direction D2. The lower surface 50b of the MR element 50 is in contact with the lower electrode 61. Each of the two side surfaces 50c and the two side surfaces 50d is inclined with respect to the stacking direction of the multiple magnetic films (a direction parallel to the Z direction).

[0048] The magnetic sensor 1 further includes at least one ferromagnetic layer 72 made of a ferromagnetic material and an insulating layer 32 made of an insulating material such as Al2O3 or SiO2. The at least one ferromagnetic layer 72 is arranged to overlap the MR element 50 when viewed from the first direction D1. In this embodiment, in particular, the at least one ferromagnetic layer 72 is arranged to overlap the entire free layer 54 when viewed from the first direction D1.

[0049] Furthermore, at least one ferromagnetic layer 72 is disposed so as to ride on a side surface 50c of the MR element 50. A portion of the at least one ferromagnetic layer 72 overlaps a portion of the MR element 50 when viewed from the Z direction. The insulating layers 32 are disposed on both sides of the MR element 50 in the second direction D2.

[0050] In particular, in this embodiment, the MR element 50 is disposed between two ferromagnetic layers 72 that are disposed at a predetermined interval in the first direction D1. The insulating layer 32 is disposed around the MR element 50 and the two ferromagnetic layers 72.

[0051] The ferromagnetic layer 72 is formed of a ferromagnetic material containing one or more elements selected from the group consisting of Co, Fe, and Ni. Examples of such ferromagnetic materials include CoFe, CoFeB, and CoNiFe. The ferromagnetic layer 72 may be a laminate of multiple layers, with adjacent layers made of different ferromagnetic materials. Examples of such a ferromagnetic layer 72 include a laminate of a Co layer, a CoFe layer, and a Co layer. 70Fe 30 Layer and Co 30 Fe 70 Layer and Co 70 Fe 30 The Co 70 Fe 30 represents an alloy consisting of 70 atomic % Co and 30 atomic % Fe, and Co 30 Fe 70 represents an alloy consisting of 30 atomic % Co and 70 atomic % Fe.

[0052] The magnetic sensor 1 further includes two buffer layers 71 arranged on the lower surface side (-Z direction side) of each of the two ferromagnetic layers 72. The two buffer layers 71 are formed of a non-magnetic metal material such as Ru, Ta, Cu, or Cr.

[0053] The magnetic sensor 1 further includes an antiferromagnetic layer 74 disposed on the MR element 50, the two ferromagnetic layers 72, and the insulating layer 32, and a cap layer 75 disposed on the antiferromagnetic layer 74. The antiferromagnetic layer 74 includes two antiferromagnetic portions 74a facing the two ferromagnetic layers 72 and a non-facing portion 74b facing the MR element 50 and the insulating layer 32 but not facing the two ferromagnetic layers 72. The two antiferromagnetic portions 74a are connected to each other by the non-facing portion 74b. No magnetic layer exists between the MR element 50 and the antiferromagnetic layer 74. The cap layer 75 includes two protective portions 75a disposed on the two antiferromagnetic portions 74a.

[0054] The antiferromagnetic layer 74 is made of an antiferromagnetic material such as IrMn, PtMn, etc. The cap layer 75 is made of a nonmagnetic metal material such as Ru, Ta, Cu, or Cr, for example.

[0055] The buffer layer 71 and the ferromagnetic layer 72 constitute a first stacked structure 701. The antiferromagnetic layer 74 and the cap layer 75 constitute a second stacked structure 702. The MR element 50 is disposed between the two first stacked structures 701. The second stacked structure 702 is disposed on the MR element 50, the insulating layer 32, and the two first stacked structures 701.

[0056] The second laminate 702 includes two laminate portions 702a disposed on the two first laminate portions 701. Each of the two laminate portions 702a includes an antiferromagnetic portion 74a and a protective portion 75a.

[0057] The ferromagnetic layer 72 has a magnetization of the entire ferromagnetic layer 72. The magnetization of the entire ferromagnetic layer 72 is the volume-averaged vector sum of the magnetic moments of each unit, such as an atom or crystal lattice, in the entire ferromagnetic layer 72. Hereinafter, the magnetization of the entire ferromagnetic layer 72 will be simply referred to as the magnetization of the ferromagnetic layer 72. In a stack consisting of the first stack 701 and the stack portion 702a disposed on the first stack 701, the antiferromagnetic portion 74a contacts the top surface of the ferromagnetic layer 72 and is exchange-coupled with the ferromagnetic layer 72. This determines the direction of the magnetization of the ferromagnetic layer 72. The ferromagnetic layer 72 and the antiferromagnetic portion 74a constitute a magnetic field generator 70 that generates a bias magnetic field applied to the MR element 50 based on the magnetization of the ferromagnetic layer 72. The magnetic field generator 70 configured in this manner has high resistance to external disturbance magnetic fields.

[0058] The ferromagnetic layer 72 is part of the first stack 701, and the antiferromagnetic portion 74a is part of the stack portion 702a. Therefore, the first stack 701 and the stack portion 702a can be said to constitute the magnetic field generator 70. The magnetic field generator 70 includes a buffer layer 71, a ferromagnetic layer 72, an antiferromagnetic portion 74a, and a protective portion 75a. The MR element 50 is disposed between the two magnetic field generators 70. The two magnetic field generators 70 cooperate to apply a bias magnetic field to the MR element 50. The magnetization direction of the ferromagnetic layer 72 of one of the two magnetic field generators 70 may be the same as the magnetization direction of the ferromagnetic layer 72 of the other of the two magnetic field generators 70. In this case, the direction of the bias magnetic field generated by one of the two magnetic field generators 70 is the same as the direction of the bias magnetic field generated by the other of the two magnetic field generators 70.

[0059] The upper surface 50a of the MR element 50 faces the non-facing portion 74b of the antiferromagnetic layer 74. The distance between at least a part of the non-facing portion 74b and the lower surface 50b of the MR element 50 is the same as the distance between the upper surface 50a and the lower surface 50b. The distance between the antiferromagnetic portion 74a of the antiferromagnetic layer 74 and the upper surface of the lower electrode 61 may be the same as the distance between the non-facing portion 74b and the lower surface 50b, or may be different from the distance between the non-facing portion 74b and the lower surface 50b. In the latter case, the maximum distance between the antiferromagnetic portion 74a and the upper surface of the lower electrode 61 may be larger or smaller than the distance between the non-facing portion 74b and the lower surface 50b.

[0060] The ferromagnetic layer 72 has a side surface 72a facing the side surface 50c of the MR element 50. The side surface 72a faces the free layer 54 of the MR element 50 and includes an inclined portion 72a1 that is inclined with respect to the stacking direction of the multiple magnetic films (a direction parallel to the Z direction). The angle that the inclined portion 72a1 forms with respect to the stacking direction is within a range of 20° to 90°.

[0061] The magnetic sensor 1 further includes an insulating layer 31 made of an insulating material and interposed between the substrate 30 (see FIGS. 4 to 6) and the lower electrode 61, and an insulating layer 33 made of an insulating material and interposed between the MR element 50 and the two first laminates 701. The insulating layers 31 and 33 are formed of an insulating material such as Al2O3 or SiO2.

[0062] The upper surface of the second laminate 702, i.e., the upper surface of the cap layer 75, is in contact with the upper electrode 62. The planar shape of the second laminate 702 (shape viewed from the Z direction) may be the same as the planar shape of the upper electrode 62, or may be smaller or larger than the planar shape of the upper electrode 62. The magnetic sensor 1 further includes an insulating layer (not shown) made of an insulating material and arranged on the upper electrode 62.

[0063] Up to this point, the configurations of the MR element 50 and the magnetic field generator 70 have been described, focusing on one MR element 50. In this embodiment, the magnetic sensor 1 includes a plurality of MR elements 50. As shown in FIG. 7 , the plurality of MR elements 50 includes two MR elements 50 arranged along the second direction D2. A second laminate 702 is interposed between the two MR elements 50 and the upper electrode 62 that electrically connects the two MR elements 50. In the example shown in FIG. 7 , the second laminate 702 is disposed on the two MR elements 50 and four first laminates 701. In this example, the second laminate 702 includes four laminate portions 702a.

[0064] The two MR elements 50 are also electrically connected by the antiferromagnetic layer 74 of the second stack 702. The two MR elements 50 are also connected in series by the antiferromagnetic layer 74.

[0065] In addition, in this embodiment, since the magnetic sensor 1 has multiple MR elements 50 and multiple magnetic field generators 70, the magnetic sensor 1 has multiple buffer layers 71, multiple ferromagnetic layers 72, multiple antiferromagnetic layers 74 and multiple cap layers 75.

[0066] Next, the operation and effect of the magnetic sensor 1 according to this embodiment will be described. In this embodiment, the antiferromagnetic layer 74 is disposed on the MR element 50, the two ferromagnetic layers 72, and the insulating layer 32. No magnetic layer exists between the MR element 50 and the antiferromagnetic layer 74. As a result, according to this embodiment, it is possible to prevent the sensitivity of the MR element 50 from decreasing.

[0067] Furthermore, in this embodiment, the antiferromagnetic layer 74 includes an antiferromagnetic portion 74a that is exchange-coupled with the ferromagnetic layer 72 to determine the direction of magnetization of the ferromagnetic layer 72. As will be described later, in this embodiment, the base portion on which the antiferromagnetic layer 74 is formed is flat or substantially flat, and the antiferromagnetic layer 74 can be formed without any structure being provided on the base portion. As a result, this embodiment can prevent the film thickness of the antiferromagnetic portion 74a from becoming small. As a result, this embodiment can effectively use the antiferromagnetic portion 74a, and as a result, the above-mentioned function of the antiferromagnetic portion 74a and the function of the magnetic field generator 70 can be realized.

[0068] Furthermore, in this embodiment, a cap layer 75 is formed on the antiferromagnetic layer 74. The cap layer 75 includes a protective portion 75a that protects the antiferromagnetic portion 74a. According to this embodiment, by forming the cap layer 75 on the antiferromagnetic layer 74, it is possible to prevent the film thickness of the protective portion 75a from becoming small. As a result, according to this embodiment, it is possible to effectively use the protective portion 75a, and as a result, it is possible to realize the above-mentioned function of the protective portion 75a.

[0069] The above effects will be described in detail below, in comparison with a comparative magnetic sensor equipped with a comparative magnetic field generator. First, the configuration of the comparative magnetic sensor will be described. The comparative magnetic sensor is equipped with a comparative magnetic field generator 170 instead of the magnetic field generator 70 of the present embodiment.

[0070] The magnetic field generator 170 includes a buffer layer 171, a ferromagnetic layer 172, an antiferromagnetic layer 173, and a cap layer 174. The buffer layer 171, the ferromagnetic layer 172, the antiferromagnetic layer 173, and the cap layer 174 correspond to the buffer layer 71, the ferromagnetic layer 72, the antiferromagnetic layer 74, and the cap layer 75 in the present embodiment, respectively. In the comparative example, the antiferromagnetic layer 173 is in contact with the top surface of the ferromagnetic layer 172 and exchange-couples with the ferromagnetic layer 172. This defines the direction of magnetization of the ferromagnetic layer 172.

[0071] 11 is a cross-sectional view showing a method for forming a magnetic field generator of a comparative example. The magnetic field generator 170 of the comparative example is formed as follows. First, the laminated film that will later become the MR element 50 is patterned to form two side surfaces 50d (see FIG. 10) on this laminated film. Next, an insulating layer 32 (see FIGS. 8 and 10) is formed around the laminated film.

[0072] 11, a photoresist mask 81 is formed on the laminated film. Next, using the photoresist mask 81, the laminated film is patterned by etching so that two side surfaces 50c are formed in the laminated film. As a result, the laminated film becomes the MR element 50.

[0073] Next, with the photoresist mask 81 remaining, the insulating layer 131, buffer layer 171, ferromagnetic layer 172, antiferromagnetic layer 173, and cap layer 174 are formed in this order. This completes the magnetic field generator 170. Next, the photoresist mask 81 is removed. Note that the photoresist mask 81 may be formed after the MR element 50 has been patterned.

[0074] 11, the thickness of the antiferromagnetic layer 173 decreases toward the photoresist mask 81 due to the shadow of the photoresist mask 81. Therefore, near the corners where the top surface 50a and the side surface 50c of the MR element 50 intersect, the blocking temperature of the antiferromagnetic layer 173 decreases, and the heat resistance of the antiferromagnetic layer 173 decreases. Therefore, in an environment where the temperature is elevated temporarily or for a long period of time, the antiferromagnetic layer 173 and the magnetic field generator 170 cannot function properly.

[0075] Similarly, the thickness of the cap layer 174 decreases as it approaches the photoresist mask 81 due to the influence of the shadow of the photoresist mask 81. Therefore, the antiferromagnetic layer 173 cannot be sufficiently protected near the corners, and there is a risk of corrosion of the antiferromagnetic layer 173. If the antiferromagnetic layer 173 corrodes, it will no longer be possible for the antiferromagnetic layer 173 and the magnetic field generator 170 to function properly.

[0076] In contrast, in this embodiment, it is possible to prevent the film thickness of each of the antiferromagnetic portion 74a and the protective portion 75a from becoming small. Figure 12 is a cross-sectional view showing a method for forming the magnetic field generator 70 in this embodiment. The magnetic field generator 70 in this embodiment is formed as follows. First, a laminated film that will later become the MR element 50 is patterned to form two side surfaces 50d (see Figure 10) on this laminated film. Next, an insulating layer 32 (see Figures 8 and 10) is formed around the laminated film.

[0077] 12(a), a photoresist mask 82 is formed on the laminated film. Next, using the photoresist mask 82, the laminated film is patterned by etching so that two side surfaces 50c are formed in the laminated film. This turns the laminated film into the MR element 50. Next, with the photoresist mask 82 remaining, the insulating layer 33, buffer layer 71, and ferromagnetic layer 72 are formed in this order.

[0078] 12(b), the photoresist mask 82 is removed. Next, an antiferromagnetic layer 74 and a cap layer 75 are formed in this order on the MR element 50, the ferromagnetic layer 72, and the insulating layer 32. Next, a step of fixing the magnetization direction of the ferromagnetic layer 72 is performed. This completes the magnetic field generator 70. The step of fixing the magnetization direction of the ferromagnetic layer 72 will be described in detail later.

[0079] As shown in FIG. 12(b), in this embodiment, the antiferromagnetic layer 74 and the cap layer 75 are formed on a stack of the MR element 50, the ferromagnetic layer 72, and the insulating layer 32. The top surface of this stack is flat or nearly flat. Furthermore, when the antiferromagnetic layer 74 and the cap layer 75 are formed, no structures such as photoresist masks are present on the stack. For these reasons, in this embodiment, the film thicknesses of the antiferromagnetic layer 74 and the cap layer 75 are constant or nearly constant regardless of the distance from the MR element 50. As such, this embodiment can prevent the film thicknesses of the antiferromagnetic portion 74a and the protective portion 75a from becoming small. As a result, this embodiment enables the antiferromagnetic portion 74a and the protective portion 75a to be used effectively.

[0080] Furthermore, in this embodiment, the insulating layer 32 functions to suppress variations in the thickness of each layer formed on the MR element 50. In other words, if the insulating layer 32 were not present, portions of the antiferromagnetic layer 74 and the cap layer 75 would be formed along the two side surfaces 50d of the MR element 50. In this case, the thicknesses of the layers formed along the two side surfaces 50d of the MR element 50 would differ from the thicknesses of the layers formed along the top surface 50a of the MR element 50 and the top surface of the ferromagnetic layer 72. In contrast, in this embodiment, the antiferromagnetic layer 74 and the cap layer 75 are formed along the top surface 50a of the MR element 50, the top surface of the ferromagnetic layer 72, and the top surface of the insulating layer 32, thereby suppressing variations in the thickness of each layer. Furthermore, by forming the antiferromagnetic layer 74 and the cap layer 75 using a method with good step coverage, variations in the thickness of each layer can be more effectively suppressed. This also enables the antiferromagnetic portion 74a and the protective portion 75a to be used effectively in this embodiment.

[0081] Next, a brief description will be given of a method for forming the plurality of MR elements 50 in this embodiment. In the process of forming the plurality of MR elements 50, first, a plurality of initial MR elements are formed, which will later become the plurality of MR elements 50. Each of the plurality of initial MR elements includes an initial magnetization fixed layer, which will later become the magnetization fixed layer 52, a buffer layer 51, a gap layer 53, a free layer 54, and a cap layer 55.

[0082] Next, the magnetization direction of the initial magnetization fixed layer is fixed in the predetermined direction using laser light and an external magnetic field containing a component in a predetermined direction. For example, for the initial MR elements that will later become the MR elements 50A that constitute the resistor units R11 and R13 of the first detection circuit 10, laser light is irradiated onto the initial MR elements while applying an external magnetic field in the X direction. When the irradiation of the laser light is completed, the magnetization direction of the initial magnetization fixed layer is fixed in the X direction. As a result, the initial magnetization fixed layer becomes the magnetization fixed layer 52, and the initial MR element becomes the MR element 50A.

[0083] Furthermore, in the initial MR elements that will later become the MR elements 50A that will constitute the resistor sections R12, R14 of the first detection circuit 10, the magnetization direction of the initial magnetization pinned layer of each of the initial MR elements can be fixed in the -X direction by using an external magnetic field in the -X direction. In this way, the MR elements 50A are formed. The MR elements 50B that will constitute the resistor sections R21 to R24 of the second detection circuit 20 are also formed in the same manner as the MR elements 50A.

[0084] Next, the process of fixing the magnetization direction of the ferromagnetic layer 72 will be described. The magnetization direction of the ferromagnetic layer 72 is fixed by the same method as the magnetization fixed layer 52 of the MR element 50. That is, as described with reference to FIGS. 12(a) and 12(b), first, the antiferromagnetic layer 74 and the cap layer 75 are formed, and then the magnetization direction of the ferromagnetic layer 72 is fixed in the predetermined direction using laser light and an external magnetic field containing a component in a predetermined direction. For example, the multiple ferromagnetic layers 72 arranged near the multiple MR elements 50A that will later constitute the resistors R11 and R12 of the first detection circuit 10 are irradiated with laser light while applying an external magnetic field in the Y direction. When the irradiation of the laser light is completed, the magnetization direction of the ferromagnetic layer 72 is fixed in the Y direction.

[0085] Furthermore, by using an external magnetic field in the −Y direction, it is possible to fix the magnetization direction of each of the ferromagnetic layers 72 arranged near the MR elements 50A that respectively constitute the resistor units R13 and R14 of the first detection circuit 10 in the −Y direction. The magnetization direction of each of the ferromagnetic layers 72 arranged near the MR elements 50B that respectively constitute the resistor units R21 to R24 of the second detection circuit 20 is also fixed in the same manner as above.

[0086] The intensity of the laser light used to fix the magnetization direction of the ferromagnetic layer 72 may be smaller than the intensity of the laser light used to fix the magnetization direction of the magnetization fixed layer 52. Furthermore, the intensity of the laser light used to fix the magnetization direction of the ferromagnetic layer 72 is preferably an intensity that suppresses changes in the magnetoresistance change rate, which is the ratio of magnetoresistance change to the resistance of the MR element 50.

[0087] [Variations] Next, first to seventh modified examples of the magnetic sensor 1 according to the present embodiment will be described. First, the first modified example will be described with reference to FIG. 13. FIG. 13 is a plan view showing a main part of the first modified example of the magnetic sensor 1. In the first modified example, each of the plurality of lower electrodes 61 electrically connects two adjacent MR elements 50 in the first direction D1. Each of the plurality of upper electrodes 62 is disposed on two lower electrodes 61 and electrically connects two adjacent MR elements 50. As a result, the plurality of MR elements 50 lined up in a row in the first direction D1 are connected in series. In the first modified example, the plurality of connection electrodes electrically connect the plurality of lower electrodes 61 or the plurality of upper electrodes 62 so that a group of the plurality of MR elements 50 lined up in a row is connected in series.

[0088] In the first modification, a second stacked body 702 is interposed between the two MR elements 50 aligned in the first direction D1 and the upper electrode 62. The two MR elements 50 are also electrically connected by the antiferromagnetic layer 74 (see FIGS. 9 and 10) of the second stacked body 702. The two MR elements 50 are also connected in series by the antiferromagnetic layer 74.

[0089] Next, a second modified example will be described with reference to FIG. 14. FIG. 14 is a plan view showing a main portion of the second modified example of the magnetic sensor 1. In the second modified example, two MR elements 50 and three magnetic field generators 70 are arranged between a lower electrode 61 and an upper electrode 62. Here, the three magnetic field generators 70 are referred to as "first," "second," and "third." The first magnetic field generator 70 is arranged between two MR elements 50 aligned along the first direction D1. The second magnetic field generator 70 is arranged in a position where one of the two MR elements 50 is sandwiched between the first magnetic field generator 70 and the second magnetic field generator 70. The third magnetic field generator 70 is arranged in a position where the other of the two MR elements 50 is sandwiched between the first magnetic field generator 70 and the third magnetic field generator 70.

[0090] The two MR elements 50 shown in FIG. 14 are connected to the same bottom electrode 61 and the same top electrode 62. These two MR elements 50 are connected in parallel in the circuit configuration. Here, two MR elements 50 connected in parallel in the circuit configuration are referred to as an element pair. Each of the multiple bottom electrodes 61 electrically connects two adjacent element pairs in the second direction D2. Each of the multiple top electrodes 62 is disposed on two bottom electrodes 61 and electrically connects two adjacent element pairs. As a result, the multiple element pairs aligned in a row in the second direction D2 are connected in series.

[0091] A second stacked body 702 is interposed between the two element pairs and the upper electrode 62 that electrically connects the two element pairs. In the second modified example, the second stacked body 702 is disposed on four MR elements 50 and six first stacked bodies 701. In the second modified example, the second stacked body 702 includes six stacked portions 702a.

[0092] Next, a third modified example will be described with reference to Fig. 15. Fig. 15 is a plan view showing a main part of the third modified example of the magnetic sensor 1. In the third modified example, two MR elements 50 aligned along the second direction D2 are disposed between two magnetic field generators 70 aligned along the first direction D1.

[0093] The two MR elements 50 shown in FIG. 15 are connected to the same lower electrode 61 and the same upper electrode 62. These two MR elements 50 are an element pair connected in parallel in the circuit configuration. Each of the multiple lower electrodes 61 electrically connects two adjacent element pairs in the second direction D2. Each of the multiple upper electrodes 62 is disposed on two lower electrodes 61 and electrically connects two adjacent element pairs. This connects multiple element pairs aligned in a row in the second direction D2 in series.

[0094] A second stacked body 702 is interposed between the two element pairs and the upper electrode 62 that electrically connects the two element pairs. In the third modification, the second stacked body 702 is disposed on the four MR elements 50 and the four first stacked bodies 701. In the third modification, the second stacked body 702 includes four stacked portions 702a.

[0095] Next, a fourth modified example will be described with reference to Fig. 16. Fig. 16 is a cross-sectional view showing a main part of the fourth modified example of the magnetic sensor 1. In the fourth modified example, the first stack 701 includes, in addition to a buffer layer 71 and a ferromagnetic layer 72, an antiferromagnetic layer 76 disposed between the buffer layer 71 and the ferromagnetic layer 72. The antiferromagnetic layer 76 is formed of an antiferromagnetic material such as IrMn or PtMn.

[0096] The antiferromagnetic layer 76 is in contact with the lower surface of the ferromagnetic layer 72 and is exchange-coupled to the ferromagnetic layer 72. As described above, the antiferromagnetic portion 74a is exchange-coupled to the ferromagnetic layer 72. In the fourth modification, the antiferromagnetic portion 74a and the antiferromagnetic layer 76 are exchange-coupled to the ferromagnetic layer 72, thereby defining the direction of magnetization of the ferromagnetic layer 72.

[0097] Next, a fifth modified example will be described with reference to FIG. 17. FIG. 17 is a cross-sectional view showing a main portion of the fifth modified example of the magnetic sensor 1. In the fifth modified example, the first stack 701 includes a buffer layer 71 and a ferromagnetic layer 72, as well as a ferromagnetic layer 77 disposed between the buffer layer 71 and the ferromagnetic layer 72. The ferromagnetic layer 77 is made of a ferromagnetic material containing one or more elements of Co, Fe, and Ni. In the fifth modified example, the ferromagnetic layer 77 has a magnetization in the same direction as the magnetization of the ferromagnetic layer 72.

[0098] In a fifth modification, the ferromagnetic layer 72 may be formed from a ferromagnetic material that can increase the exchange coupling energy with the antiferromagnetic portion 74a, and the ferromagnetic layer 77 may be formed from a ferromagnetic material that has a higher saturation magnetic flux density than the ferromagnetic material that constitutes the ferromagnetic layer 72. In this case, the exchange coupling energy between the ferromagnetic portion consisting of the ferromagnetic layers 72 and 77 and the antiferromagnetic portion 74a is increased, while the strength of the bias magnetic field generated by the magnetic field generator 70 can be increased and the magnetic field generator 70 can be made smaller. An example of the ferromagnetic layer 72 is Co. 70 Fe 30 Examples of the ferromagnetic layer 77 include a Co 30 Fe 70 layers.

[0099] Next, a sixth modified example will be described with reference to FIG. 18 . FIG. 18 is a cross-sectional view showing a main portion of the sixth modified example of the magnetic sensor 1. In the sixth modified example, the first stack 701 includes, in addition to a buffer layer 71 and a ferromagnetic layer 72, a ferromagnetic layer 78 disposed between the buffer layer 71 and the ferromagnetic layer 72, and a nonmagnetic layer 79 disposed between the ferromagnetic layer 72 and the ferromagnetic layer 78. The ferromagnetic layer 78 is formed of a ferromagnetic material containing one or more elements selected from Co, Fe, and Ni. The ferromagnetic layers 72 and 78 may be formed of the same ferromagnetic material or different ferromagnetic materials. The nonmagnetic layer 79 is formed of a nonmagnetic metal material, such as Ru.

[0100] In the sixth modification, the ferromagnetic layer 72 and the ferromagnetic layer 78 are ferromagnetically exchange-coupled via the nonmagnetic layer 79 so that their magnetization directions are the same. The ferromagnetic layer 72 and the ferromagnetic layer 78 have magnetizations in the same direction. The thickness of the nonmagnetic layer 79 is set so that the exchange coupling between the ferromagnetic layer 72 and the ferromagnetic layer 78 is not lost.

[0101] Next, a seventh modification will be described with reference to Fig. 19. In the seventh modification, the two side surfaces 50c of the MR element 50 are formed by etching at least the gap layer 53, the free layer 54, and the cap layer 55 in the process of patterning the stacked film described with reference to Fig. 12(a). In this process, the magnetization fixed layer 52 may or may not be partially etched.

[0102] In the seventh modification, the ferromagnetic layer 72 is disposed so as to overlap the side surface 50c of the MR element 50 and the magnetization fixed layer 52. The insulating layer 33 is formed along the side surface 50c of the MR element 50 and the upper surface of the magnetization fixed layer 52.

[0103] The first to seventh modified examples can be combined in any manner. For example, the first modified example shown in Fig. 13 may be combined with the second modified example shown in Fig. 14 or the third modified example shown in Fig. 15. In this case, a pair of two MR elements 50 adjacent to each other in the first direction D1 is electrically connected.

[0104] [Second embodiment] Next, a second embodiment of the present invention will be described. First, the configuration of a magnetic sensor system including a magnetic sensor according to this embodiment will be described with reference to Fig. 20. Fig. 20 is a perspective view showing a magnetic sensor system 200 according to this embodiment.

[0105] The magnetic sensor system 200 includes a magnetic sensor 201 according to this embodiment and a magnetic field generating unit 202 that generates a predetermined magnetic field. In this embodiment, the magnetic field generating unit 202 is a magnet configured so that a partial magnetic field, which is a part of the magnetic field that it generates, is applied to the magnetic sensor 201. This partial magnetic field includes a first magnetic field component Hz parallel to the Z direction and a second magnetic field component Hy parallel to the Y direction.

[0106] 20, in this embodiment, the magnetization direction of the magnetic field generating unit 202 is the Y direction, and the direction of the second magnetic field component Hy is the -Y direction. The direction of the first magnetic field component Hz becomes the Z direction when the magnetic field generating unit 202 moves in the Y direction from a predetermined position, and becomes the -Z direction when the magnetic field generating unit 202 moves in the -Y direction from a predetermined position.

[0107] Next, a schematic configuration of a magnetic sensor 201 according to this embodiment will be described with reference to Fig. 21. Fig. 21 is a circuit diagram showing the circuit configuration of the magnetic sensor 201.

[0108] The magnetic sensor 201 includes four resistors R31, R32, R33, and R34, a power supply port V3, a ground port G3, and two output ports E31 and E32. The resistor R31 is provided between the power supply port V3 and the output port E31. The resistor R32 is provided between the output port E31 and the ground port G3. The resistor R33 is provided between the output port E32 and the ground port G3. The resistor R34 is provided between the power supply port V3 and the output port E32. A voltage or current of a predetermined magnitude is applied to the power supply port V3. The ground port G3 is connected to ground.

[0109] Each of the resistor units R31 to R34 includes a plurality of MR elements 50. The configuration of the plurality of MR elements 50 is the same as that of the first embodiment. That is, each of the plurality of MR elements 50 includes a buffer layer 51, a magnetization fixed layer 52, a gap layer 53, a free layer 54, and a cap layer 55, as shown in FIGS. 9 and 10 in the first embodiment.

[0110] 21, a plurality of solid arrows drawn to overlap the resistor units R31 to R34 respectively represent the magnetization direction of the magnetization fixed layer 52 in each of the resistor units R31 to R34. In the example shown in FIG. 21, the direction of the main component of the magnetization of the magnetization fixed layer 52 in each of the resistor units R31 and R34 is the X direction. The direction of the main component of the magnetization of the magnetization fixed layer 52 in each of the resistor units R32 and R33 is the −X direction. The free layer 54 in each of the resistor units R31 to R34 has shape anisotropy in which the direction of the easy axis of magnetization is parallel to the Y direction.

[0111] Each of the resistor sections R31 to R34 further includes a plurality of magnetic field generators 70. The configuration of the plurality of magnetic field generators 70 is the same as that of the first embodiment. The plurality of magnetic field generators 70 includes a plurality of pairs of magnetic field generators 70, each consisting of two magnetic field generators 70. The two magnetic field generators 70 are arranged at a predetermined interval in a direction parallel to the Y direction so as to sandwich one MR element 50 therebetween. The two magnetic field generators 70 are configured to apply a bias magnetic field to the one MR element 50 located between them. This bias magnetic field mainly includes a component parallel to the Y direction.

[0112] 21, the arrows labeled M31, M32, M33, and M34 indicate the directions of the main components of the bias magnetic fields generated by the multiple magnetic field generators 70 in the resistor units R31, R32, R33, and R34, respectively. The direction of the main component of the bias magnetic field in the resistor units R31 and R34 is the Y direction. The direction of the main component of the bias magnetic field in the resistor units R32 and R33 is the -Y direction.

[0113] 21, multiple open arrows drawn to overlap the resistor units R31 to R34 indicate the direction of magnetization of the free layer in each of the resistor units R31 to R34 when no partial magnetic field is applied to the magnetic sensor 201. The direction of the main component of the magnetization of the free layer in each of the resistor units R31 and R34 is the Y direction, which is the same as the direction of the main component of the bias magnetic field in the resistor units R31 and R34. The direction of the main component of the magnetization of the free layer in each of the resistor units R32 and R33 is the -Y direction, which is the same as the direction of the main component of the bias magnetic field in the resistor units R32 and R33.

[0114] Next, the configuration of the magnetic sensor 201 will be specifically described with reference to Fig. 22 to Fig. 24. Fig. 22 is a perspective view showing a part of the magnetic sensor 201. Fig. 23 is a plan view showing a part of the magnetic sensor 201. Fig. 24 is a side view showing a part of the magnetic sensor 201.

[0115] The magnetic sensor 201 further includes a substrate 230. The magnetic sensor 201 is configured by forming a plurality of components other than the substrate 230 on the substrate 230.

[0116] The magnetic sensor 201 further includes at least one yoke made of a soft magnetic material. When viewed from the Z direction, the at least one yoke has a shape that is elongated in the Y direction. The at least one yoke generates a magnetic field component parallel to the X direction based on the first magnetic field component Hz shown in FIG. 20.

[0117] As shown in FIGS. 22 to 24 , in this embodiment, magnetic sensor 201 includes, as at least one yoke, a plurality of yokes 250 arranged side by side in the X direction. Each of the plurality of yokes 250 has, for example, a rectangular parallelepiped shape that is long in the Y direction. The plurality of yokes 250 have the same shape. Each of the plurality of yokes 250 has a first end face 250a and a second end face 250b located at both ends in a direction parallel to the X direction. In each of the plurality of yokes 250, first end face 250a is located at the end in the −X direction, and second end face 250b is located at the end in the X direction.

[0118] Each of the multiple MR elements 50 is disposed at a position where a magnetic field component generated by the multiple yokes 250 is applied. In particular, in this embodiment, each of the MR elements 50 is disposed near the end of each of the multiple yokes 250 in the -Z direction. The multiple MR elements 50 are also disposed so that multiple elements are lined up along the first end face 250a or the second end face 250b of each of the multiple yokes 250. Hereinafter, of the multiple MR elements 50, the multiple MR elements lined up along the first end face 250a will be denoted by reference symbol 50C, and the multiple MR elements lined up along the second end face 250b will be denoted by reference symbol 50D. The direction of the magnetic field component received by the multiple MR elements 50C and the direction of the magnetic field component received by the multiple MR elements 50D are opposite to each other.

[0119] When viewed from the Z direction, the multiple MR elements 50C and the multiple MR elements 50D may or may not overlap with the multiple yokes 250. In the examples shown in Figures 22 to 24, the multiple MR elements 50C and the multiple MR elements 50D are arranged so as not to overlap with the multiple yokes 250 when viewed from the Z direction.

[0120] As shown in FIGS. 22 and 23 , of the multiple magnetic field generators 70, the multiple magnetic field generators arranged to sandwich the MR element 50C are denoted by reference numeral 70C, and the multiple magnetic field generators arranged to sandwich the MR element 50D are denoted by reference numeral 70D. The magnetic sensor 201 further includes multiple yokes 90C and multiple yokes 90D, each including a magnetic layer made of a soft magnetic material. The multiple yokes 90C include multiple pairs of yokes 90C, each consisting of two yokes 90C. The two yokes 90C are arranged on both sides of one MR element 50C in a direction parallel to the X direction. The multiple yokes 90D include multiple pairs of yokes 90D, each consisting of two yokes 90D. The two yokes 90D are arranged on both sides of one MR element 50D in a direction parallel to the X direction.

[0121] The plurality of yokes 90C have a function of guiding the magnetic field components generated by the plurality of yokes 250 to the plurality of MR elements 50C. The plurality of yokes 90D have a function of guiding the magnetic field components generated by the plurality of yokes 250 to the plurality of MR elements 50D.

[0122] The magnetic sensor 201 further includes a wiring section 211 that electrically connects the plurality of MR elements 50C and a wiring section 212 that electrically connects the plurality of MR elements 50D. Each of the wiring sections 211 and 212 is composed of a plurality of lower electrodes 61, a plurality of upper electrodes 62, and a plurality of connecting electrodes. The lower electrodes 61 and the upper electrodes 62 are shown in Figures 25 to 27, which will be described later.

[0123] The wiring section 211 includes a first wiring that electrically connects the plurality of MR elements 50C whose magnetization fixed layer 52 has a main component of magnetization oriented in the X direction, and a second wiring that electrically connects the plurality of MR elements 50C whose magnetization fixed layer 52 has a main component of magnetization oriented in the −X direction. The resistor section R31 is composed of the plurality of MR elements 50C electrically connected by the first wiring. The resistor section R32 is composed of the plurality of MR elements 50C electrically connected by the second wiring.

[0124] The wiring section 212 includes a third wiring that electrically connects the plurality of MR elements 50D, each of which has a magnetization pinned layer 52 whose main component of magnetization is oriented in the −X direction, and a fourth wiring that electrically connects the plurality of MR elements 50D, each of which has a magnetization pinned layer 52 whose main component of magnetization is oriented in the X direction. The resistor section R33 is composed of the plurality of MR elements 50D electrically connected by the third wiring. The resistor section R34 is composed of the plurality of MR elements 50D electrically connected by the fourth wiring.

[0125] Next, we will explain the operation of the magnetic sensor 201. When the first magnetic field component Hz is not present, and as a result, when the magnetic field components generated by the plurality of yokes 250 are not present, the magnetization direction of the free layer 54 of each of the plurality of MR elements 50C and the plurality of MR elements 50D is parallel to the Y direction.

[0126] When the direction of the first magnetic field component Hz is the Z direction, the direction of the magnetic field component received by each of the multiple MR elements 50C constituting the resistor units R31 and R32 is the X direction, and the direction of the magnetic field component received by each of the multiple MR elements 50D constituting the resistor units R33 and R34 is the −X direction. In this case, the magnetization direction of the free layer 54 of each of the multiple MR elements 50C tilts from a direction parallel to the Y direction toward the X direction, and the magnetization direction of the free layer 54 of each of the multiple MR elements 50D tilts from a direction parallel to the Y direction toward the −X direction. As a result, compared to a state in which no magnetic field component is present, the resistance value of each of the multiple MR elements 50C constituting the resistor unit R31 and the resistance value of each of the multiple MR elements 50D constituting the resistor unit R33 decreases, and the resistance value of each of the multiple MR elements 50C constituting the resistor unit R32 and the resistance value of each of the multiple MR elements 50D constituting the resistor unit R34 increases. As a result, the resistance values ​​of the resistors R31 and R33 decrease, and the resistance values ​​of the resistors R32 and R34 increase.

[0127] When the direction of the first magnetic field component Hz is the -Z direction, the direction of the magnetic field component and the change in the resistance value of each of the resistor portions R31 to R34 are opposite to when the direction of the first magnetic field component Hz is the Z direction.

[0128] The amount of change in the resistance value of each of the resistor units R31 to R34 depends on the strength of the magnetic field component that each of the MR elements 50C and 50D receives. As the strength of the magnetic field component increases, the resistance value of each of the resistor units R31 to R34 changes in a direction that increases the amount of increase or decrease, respectively. As the strength of the magnetic field component decreases, the resistance value of each of the resistor units R31 to R34 changes in a direction that decreases the amount of increase or decrease, respectively. The strength of the magnetic field component depends on the strength of the first magnetic field component Hz.

[0129] In this way, when the direction and intensity of the first magnetic field component Hz change, the resistance values ​​of the resistors R31 to R34 change such that the resistance values ​​of the resistors R31 and R33 increase while the resistance values ​​of the resistors R32 and R34 decrease, or the resistance values ​​of the resistors R31 and R33 decrease while the resistance values ​​of the resistors R32 and R34 increase. This causes a change in the potential at the connection point between the resistors R31 and R32, i.e., the potential at the output port E31, and the potential at the connection point between the resistors R33 and R34, i.e., the potential at the output port E32. The magnetic sensor 201 may generate, as detection signals, a signal corresponding to the potential at the output port E31 and a signal corresponding to the potential at the output port E32. Alternatively, the magnetic sensor 201 may generate, as detection signals, a signal corresponding to the potential difference between the output ports E31 and E32. In this case, the magnetic sensor 201 may further include a differential amplifier (difference detector) that outputs a signal corresponding to the potential difference between the output ports E31 and E32 as a detection signal.

[0130] 1 and 2 in the first embodiment. The processor 2 may be configured to receive one detection signal or two detection signals output from the magnetic sensor 201, and generate a detection value corresponding to the intensity of the first magnetic field component Hz or a detection value corresponding to the position of the magnetic field generating unit 202 (see FIG. 20).

[0131] Next, the multiple yokes 90C and the multiple yokes 90D will be described in detail with reference to Figures 25 to 27. Figure 25 is a plan view showing a main part of magnetic sensor 201. Figure 26 is a cross-sectional view showing a part of a cross section taken along line 26-26 in Figure 25. Figure 27 is a cross-sectional view showing a part of a cross section taken along line 27-27 in Figure 25.

[0132] Hereinafter, any one of the plurality of yokes 90C and the plurality of yokes 90D will be represented by the reference numeral 90. The configurations and shapes of the MR element 50 and the magnetic field generator 70, and the positional relationship between the MR element 50 and the magnetic field generator 70, are the same as those in the first embodiment. The configurations and shapes of the first and second laminates 701, 702, and the positional relationship between the MR element 50 and the first and second laminates 701, 702 are also the same as those in the first embodiment.

[0133] Here, the configuration of the yoke 90 will be described, focusing on one MR element 50. The two yokes 90 are arranged on both sides of the MR element 50 in a direction parallel to the X direction. The magnetic sensor 201 further includes insulating layers 232 made of an insulating material such as Al2O3 or SiO2. The insulating layers 232 are arranged on both sides of the MR element 50 in a direction parallel to the X direction. In this embodiment in particular, the insulating layers 232 are arranged around the MR element 50 and the ferromagnetic layer 72 of the magnetic field generator 70.

[0134] The two yokes 90 are embedded in an insulating layer 232. The insulating layer 232 is interposed between the MR element 50 and the two yokes 90, and between the lower electrode 61 and the two yokes 90. In addition to a magnetic layer, each of the two yokes 90 may include a buffer layer interposed between the magnetic layer and the insulating layer 232 and a cap layer disposed on the magnetic layer. The buffer layer and the cap layer may be formed of, for example, a nonmagnetic metal material. Each of the two yokes 90 is disposed so as to rest on a side surface 50d of the MR element 50. A portion of each of the two yokes 90 overlaps a portion of the MR element 50 when viewed from the Z direction.

[0135] The two yokes 90 are arranged between two magnetic field generators 70 arranged at a predetermined interval in a direction parallel to the Y direction. The ferromagnetic layer 72 of the magnetic field generator 70 (first laminate 701) is arranged so as to overlap the two yokes 90 when viewed from the Y direction or the -Y direction.

[0136] The ferromagnetic layer 72 is disposed so as to ride on the yoke 90. A portion of the ferromagnetic layer 72 overlaps a portion of the yoke 90 when viewed from the Z direction. The magnetic sensor 201 further includes an insulating layer 233 made of an insulating material such as Al2O3 or SiO2 and interposed between the ferromagnetic layer 72 and the yoke 90. A portion of the buffer layer 71 of the magnetic field generator 70 (first laminate 701) is interposed between the ferromagnetic layer 72 and the insulating layer 233.

[0137] In this embodiment, the antiferromagnetic layer 74 is disposed on the MR element 50, the two ferromagnetic layers 72, the two yokes 90, and the insulating layer 232. The top surface of each of the two yokes 90 may be in contact with the antiferromagnetic layer 74. The magnetic sensor 201 further includes an insulating layer 231 made of an insulating material such as Al2O3 or SiO2 and interposed between the substrate 230 (see FIG. 23) and the lower electrode 61, and an insulating layer (not shown) made of an insulating material and disposed on the upper electrode 62.

[0138] Other configurations, actions, and effects of this embodiment are the same as those of the first embodiment.

[0139] [Third embodiment] Next, a third embodiment of the present invention will be described with reference to Fig. 28 to Fig. 30. Fig. 28 is a plan view showing a main part of a magnetic sensor according to this embodiment. Fig. 29 is a cross-sectional view showing a part of a cross section indicated by line 29-29 in Fig. 28. Fig. 30 is a cross-sectional view showing a part of a cross section indicated by line 30-30 in Fig. 28.

[0140] Hereinafter, differences in the configuration of the magnetic sensor 201 according to this embodiment from the second embodiment will be described, focusing on one MR element 50. In this embodiment, each of the two magnetic field generators 70 is disposed at a predetermined distance from the MR element 50. Therefore, the ferromagnetic layer 72 of each of the two magnetic field generators 70 is disposed at a predetermined distance from the MR element 50.

[0141] Furthermore, each of the two magnetic field generators 70 is disposed at a predetermined distance from the two yokes 90. Therefore, the ferromagnetic layer 72 of each of the two magnetic field generators 70 is disposed at a predetermined distance from the two yokes 90.

[0142] In this embodiment, the insulating layer 233 is interposed between the ferromagnetic layer 72 and the lower electrode 61 and insulating layer 232. The magnetic sensor 201 further includes an insulating layer 234 made of an insulating material such as Al2O3 or SiO2 and interposed between the two yokes 90 and the lower electrode 61 and insulating layer 232.

[0143] Other configurations, actions, and effects of this embodiment are the same as those of the second embodiment.

[0144] The present invention is not limited to the above-described embodiments and may be modified in various ways. For example, the magnetic sensor of the present invention may be a magnetic sensor including the first and second detection circuits 10 and 20 of the first embodiment and the magnetic sensor 201 of the second embodiment as a third detection circuit. In this magnetic sensor, the third detection circuit (magnetic sensor 201) may be configured to detect a component of the target magnetic field in a direction parallel to the Z direction. This magnetic sensor may also be a geomagnetic sensor in which the target magnetic field is the geomagnetism.

[0145] Alternatively, the MR element 50 may be configured by laminating the buffer layer 51, the free layer 54, the gap layer 53, the magnetization fixed layer 52, and the cap layer 55 in this order from the lower electrode 61 side.

[0146] As described above, the magnetic sensor of the present invention includes at least one magnetoresistive element including a plurality of stacked magnetic films; a first ferromagnetic layer made of a ferromagnetic material and arranged so as to overlap the at least one magnetoresistive element when viewed in a first direction perpendicular to the stacking direction of the magnetic films; insulating layers made of an insulating material and arranged on both sides of the at least one magnetoresistive element in a second direction perpendicular to both the stacking direction and the first direction; and an antiferromagnetic layer arranged on the at least one magnetoresistive element, the first ferromagnetic layer, and the insulating layer. The antiferromagnetic layer includes a first antiferromagnetic portion facing the first ferromagnetic layer and a non-facing portion facing the at least one magnetoresistive element and the insulating layer but not facing the first ferromagnetic layer. No magnetic layer is present between the at least one magnetoresistive element and the antiferromagnetic layer.

[0147] In the magnetic sensor of the present invention, the first ferromagnetic layer and the first antiferromagnetic portion may constitute a magnetic field generator that generates a magnetic field to be applied to at least one magnetoresistive element.

[0148] In the magnetic sensor of the present invention, the at least one magnetoresistive element may be a first magnetoresistive element and a second magnetoresistive element. The first magnetoresistive element and the second magnetoresistive element may be connected in series via an antiferromagnetic layer. The first magnetoresistive element and the second magnetoresistive element may be aligned along a first direction. Alternatively, the first magnetoresistive element and the second magnetoresistive element may be aligned along a second direction.

[0149] The magnetic sensor of the present invention may further include a second ferromagnetic layer made of a ferromagnetic material and arranged at a position sandwiching at least one magnetoresistive element between the first ferromagnetic layer and the antiferromagnetic layer in the first direction. The antiferromagnetic layer may further include a second antiferromagnetic portion facing the second ferromagnetic layer. The first ferromagnetic layer and the first antiferromagnetic portion may form a first magnetic field generator that generates a first magnetic field applied to at least one magnetoresistive element. The second ferromagnetic layer and the second antiferromagnetic portion may form a second magnetic field generator that generates a second magnetic field applied to at least one magnetoresistive element. The at least one magnetoresistive element may be a first magnetoresistive element and a second magnetoresistive element. The first magnetoresistive element and the second magnetoresistive element may be connected in parallel in a circuit configuration.

[0150] In the magnetic sensor of the present invention, the antiferromagnetic layer may be in contact with at least one magnetoresistive element, and the at least one magnetoresistive element may further include a nonmagnetic metal layer interposed between the antiferromagnetic layer and the plurality of magnetic films and in contact with the antiferromagnetic layer.

[0151] In the magnetic sensor of the present invention, the plurality of magnetic films may include a free layer having magnetization whose direction can be changed in response to a target magnetic field. The first ferromagnetic layer may have a side surface facing at least one magnetoresistive element. The side surface may include an inclined portion facing the free layer and inclined with respect to the stacking direction. The angle formed by the inclined portion with respect to the stacking direction may be in the range of 20° to 90°.

[0152] In the magnetic sensor of the present invention, at least one magnetoresistive element may have a first surface facing the non-facing portion and a second surface opposite the first surface, and the distance between at least a part of the non-facing portion and the second surface may be the same as the distance between the first surface and the second surface.

[0153] The magnetic sensor of the present invention may further include two yokes, each made of a soft magnetic material, disposed on either side of the at least one magnetoresistive element in the second direction, and an antiferromagnetic layer may be disposed on the at least one magnetoresistive element, the first ferromagnetic layer, the insulating layer, and the two yokes.

[0154] The magnetic sensor of the present invention may further include a first port, a second port, a third port, a first resistor arranged between the first port and the second port in the circuit configuration, and a second resistor arranged between the second port and the third port in the circuit configuration. Each of the first resistor and the second resistor may include at least one magnetoresistive element, a first ferromagnetic layer, an insulating layer, and an antiferromagnetic layer. The multiple magnetic films may include a free layer having magnetization whose direction can be changed in response to a target magnetic field. In the first resistor, the first ferromagnetic layer and the first antiferromagnetic portion may form a first magnetic field generator that generates a first magnetic field applied to at least one magnetoresistive element. In the second resistor, the first ferromagnetic layer and the first antiferromagnetic portion may form a second magnetic field generator that generates a second magnetic field applied to at least one magnetoresistive element. The first magnetic field may include a component in a first magnetic field direction parallel to the first direction as a main component. The second magnetic field may include a component in a second magnetic field direction opposite to the first magnetic field direction as a main component. In the first resistive section, the magnetization of the free layer may include a component in the first magnetic field direction when no target magnetic field is applied. In the second resistive section, the magnetization of the free layer may include a component in the second magnetic field direction when no target magnetic field is applied. [Explanation of symbols]

[0155] 1...magnetic sensor, 2...processor, 10...first detection circuit, 20...second detection circuit, 30...substrate, 31-33...insulating layer, 50, 50A, 50B...MR element, 51...buffer layer, 52...magnetization fixed layer, 53...gap layer, 54...free layer, 55...cap layer, 61...lower electrode, 62...upper electrode, 70, 70A, 70B...magnetic field generator, 71...buffer layer, 72...ferromagnetic layer, 74...antiferromagnetic layer, 74a...antiferromagnetic portion, 74b...non-opposing portion, 75...cap layer, 75a...protective portion, 76...antiferromagnetic layer, 77, 78...ferromagnetic layer, 79...non-magnetic layer, 81, 82...photoresist mask, 100...magnetic sensor device, 701...first laminate, 702...second laminate, 702a...laminated portion, D1...first direction, D2...second direction, E11, E12, E21, E22...output port, G1, G2...ground port, R11 to R14, R21 to R24...resistor portion, V1, V2...power supply port.

Claims

1. At least one magnetoresistive element including a plurality of stacked magnetic films; a first ferromagnetic layer made of a ferromagnetic material and arranged so as to overlap the at least one magnetoresistive element when viewed from a first direction perpendicular to the stacking direction of the plurality of magnetic films; a second ferromagnetic layer made of a ferromagnetic material and disposed at a position sandwiching the at least one magnetoresistance effect element between the first ferromagnetic layer and the second ferromagnetic layer in the first direction; an insulating layer made of an insulating material and disposed on both sides of the at least one magnetoresistive element in a second direction perpendicular to the stacking direction and the first direction; an antiferromagnetic layer disposed on the at least one magnetoresistive element, the first ferromagnetic layer, the second ferromagnetic layer, and the insulating layer; a first port; a second port; and a third port; and a first resistor portion disposed between the first port and the second port in a circuit configuration; a second resistor portion disposed between the second port and the third port in a circuit configuration; the antiferromagnetic layer includes a first antiferromagnetic portion facing the first ferromagnetic layer, a second antiferromagnetic portion facing the second ferromagnetic layer, and a non-facing portion facing the at least one magnetoresistive element and the insulating layer but not facing the first ferromagnetic layer or the second ferromagnetic layer; the first ferromagnetic layer and the first antiferromagnetic portion constitute a first magnetic field generator that generates a first magnetic field to be applied to the at least one magnetoresistive element; the second ferromagnetic layer and the second antiferromagnetic portion constitute a second magnetic field generator that generates a second magnetic field to be applied to the at least one magnetoresistive element; no magnetic layer is present between the at least one magnetoresistive element and the antiferromagnetic layer; each of the first resistance unit and the second resistance unit includes the at least one magnetoresistive element, the first ferromagnetic layer, the second ferromagnetic layer, the insulating layer, and the antiferromagnetic layer; the plurality of magnetic films include a free layer having a magnetization whose direction can be changed in response to a target magnetic field; In the first resistance section, each of the first magnetic field and the second magnetic field includes a component in a first magnetic field direction that is one direction parallel to the first direction as a main component, and the magnetization of the free layer includes a component in the first magnetic field direction when the target magnetic field is not applied; A magnetic sensor characterized in that in the second resistance section, each of the first magnetic field and the second magnetic field includes a component in a second magnetic field direction opposite to the first magnetic field direction as a main component, and the magnetization of the free layer includes a component in the second magnetic field direction when the target magnetic field is not applied.

2. At least one magnetoresistive effect element including a plurality of stacked magnetic films; a first ferromagnetic layer made of a ferromagnetic material and arranged so as to overlap the at least one magnetoresistive element when viewed from a first direction perpendicular to the stacking direction of the plurality of magnetic films; a second ferromagnetic layer made of a ferromagnetic material and disposed at a position sandwiching the at least one magnetoresistance effect element between the first ferromagnetic layer and the second ferromagnetic layer in the first direction; an insulating layer made of an insulating material and disposed on both sides of the at least one magnetoresistive element in a second direction perpendicular to the stacking direction and the first direction; two yokes, each made of a soft magnetic material, disposed on either side of the at least one magnetoresistive element in the second direction; an antiferromagnetic layer disposed on the at least one magnetoresistive element, the first ferromagnetic layer, the second ferromagnetic layer, the insulating layer, and the two yokes; the antiferromagnetic layer includes a first antiferromagnetic portion facing the first ferromagnetic layer, a second antiferromagnetic portion facing the second ferromagnetic layer, and a non-facing portion facing the at least one magnetoresistive element and the insulating layer but not facing the first ferromagnetic layer or the second ferromagnetic layer; the first ferromagnetic layer and the first antiferromagnetic portion constitute a first magnetic field generator that generates a first magnetic field to be applied to the at least one magnetoresistive element; the second ferromagnetic layer and the second antiferromagnetic portion constitute a second magnetic field generator that generates a second magnetic field to be applied to the at least one magnetoresistive element; A magnetic sensor, wherein no magnetic layer exists between the at least one magnetoresistive element and the antiferromagnetic layer.

3. the at least one magnetoresistive element is a first magnetoresistive element and a second magnetoresistive element, 3. The magnetic sensor according to claim 1, wherein the first magnetoresistive element and the second magnetoresistive element are connected in parallel in a circuit configuration.

4. 3. The magnetic sensor according to claim 1, wherein the antiferromagnetic layer is in contact with the at least one magnetoresistive element.

5. 5. The magnetic sensor according to claim 4, wherein the at least one magnetoresistive element further includes a non-magnetic metal layer interposed between the antiferromagnetic layer and the plurality of magnetic films and in contact with the antiferromagnetic layer.

6. The first ferromagnetic layer has a side surface facing the at least one magnetoresistive effect element, the side surface includes an inclined portion facing the free layer and inclined with respect to the stacking direction, 2. The magnetic sensor according to claim 1, wherein the angle of the inclined portion relative to the stacking direction is within a range of 20 degrees to 90 degrees.

7. The plurality of magnetic films include a free layer having magnetization whose direction can be changed in response to a target magnetic field, the first ferromagnetic layer has a side surface facing the at least one magnetoresistive element; the side surface includes an inclined portion facing the free layer and inclined with respect to the stacking direction, 3. The magnetic sensor according to claim 2, wherein the angle of the inclined portion relative to the stacking direction is within a range of 20 degrees to 90 degrees.

8. the at least one magnetoresistive element has a first surface facing the non-facing portion and a second surface opposite to the first surface; 3. The magnetic sensor according to claim 1, wherein the distance between at least a part of the non-facing portion and the second surface is the same as the distance between the first surface and the second surface.

9. A first magnetoresistive element and a second magnetoresistive element each including a plurality of stacked magnetic films; a first ferromagnetic layer made of a ferromagnetic material and arranged so as to overlap the first magnetoresistance effect element when viewed from a first direction perpendicular to the stacking direction of the plurality of magnetic films; a second ferromagnetic layer made of a ferromagnetic material and disposed at a position sandwiching the first magnetoresistance effect element between the first ferromagnetic layer and the second ferromagnetic layer in the first direction; a third ferromagnetic layer made of a ferromagnetic material and arranged so as to overlap the second magnetoresistance effect element when viewed from the first direction; a fourth ferromagnetic layer made of a ferromagnetic material and disposed at a position sandwiching the second magnetoresistance effect element between the fourth ferromagnetic layer and the third ferromagnetic layer in the first direction; an insulating layer made of an insulating material and disposed on both sides of each of the first magnetoresistive element and the second magnetoresistive element in a second direction perpendicular to the stacking direction and the first direction; an antiferromagnetic layer disposed on the first magnetoresistive element, the second magnetoresistive element, the first ferromagnetic layer, the second ferromagnetic layer, the third ferromagnetic layer, the fourth ferromagnetic layer, and the insulating layer; a first port; a second port; and a third port; and a first resistor portion disposed between the first port and the second port in a circuit configuration; a second resistor portion disposed between the second port and the third port in a circuit configuration; the antiferromagnetic layer includes a first antiferromagnetic portion facing the first ferromagnetic layer, a second antiferromagnetic portion facing the second ferromagnetic layer, a third antiferromagnetic portion facing the third ferromagnetic layer, a fourth antiferromagnetic portion facing the fourth ferromagnetic layer, and a non-facing portion facing the first magnetoresistive element, the second magnetoresistive element, and the insulating layer but not facing the first ferromagnetic layer, the second ferromagnetic layer, the third ferromagnetic layer, or the fourth ferromagnetic layer; the first ferromagnetic layer and the first antiferromagnetic portion constitute a first magnetic field generator that generates a first magnetic field to be applied to the first magnetoresistive element; the second ferromagnetic layer and the second antiferromagnetic portion constitute a second magnetic field generator that generates a second magnetic field to be applied to the first magnetoresistive element; the third ferromagnetic layer and the third antiferromagnetic portion constitute a third magnetic field generator that generates a third magnetic field to be applied to the second magnetoresistive element, the fourth ferromagnetic layer and the fourth antiferromagnetic portion constitute a fourth magnetic field generator that generates a fourth magnetic field to be applied to the second magnetoresistive element, no magnetic layer is present between the first magnetoresistive element and the antiferromagnetic layer, and the first magnetoresistive element and the second magnetoresistive element are connected in series via the antiferromagnetic layer; each of the first resistance unit and the second resistance unit includes the first magnetoresistive element, the second magnetoresistive element, the first ferromagnetic layer, the second ferromagnetic layer, the third ferromagnetic layer, the fourth ferromagnetic layer, the insulating layer, and the antiferromagnetic layer; the plurality of magnetic films include a free layer having a magnetization whose direction can be changed in response to a target magnetic field; In the first resistance section, each of the first magnetic field, the second magnetic field, the third magnetic field, and the fourth magnetic field includes a component in a first magnetic field direction that is one direction parallel to the first direction as a main component, and the magnetization of the free layer includes a component in the first magnetic field direction when the target magnetic field is not applied; A magnetic sensor characterized in that in the second resistance section, each of the first magnetic field, the second magnetic field, the third magnetic field, and the fourth magnetic field includes a component in a second magnetic field direction opposite to the first magnetic field direction as a main component, and the magnetization of the free layer includes a component in the second magnetic field direction when the target magnetic field is not applied.

10. 10. The magnetic sensor according to claim 9, wherein the first magnetoresistive element and the second magnetoresistive element are aligned along the first direction.

11. 10. The magnetic sensor according to claim 9, wherein the first magnetoresistive element and the second magnetoresistive element are aligned along the second direction.

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