Method of manufacturing magnetic sensor

Abstract

To materialize a magnetic sensor in which a magnetization direction of a free layer can be varied.SOLUTION: A magnetic sensor 1 comprises: an MR element 50; and a magnetic field generator 70. The MR element 50 includes: a magnetization fixed layer 52; and a free layer 54. The magnetic field generator 70 includes: a ferromagnetic portion 72; and an antiferromagnetic portion 73 that is exchange-coupled with the ferromagnetic portion 72. A method of manufacturing the magnetic sensor 1 includes: a step of forming the MR element 50; and a step of forming the magnetic field generator 70. The step of forming the magnetic field generator 70 includes: a step of forming an initial magnetic field generator 70P including an initial ferromagnetic portion which becomes the ferromagnetic portion 72 later and the antiferromagnetic portion 73; and a step of fixing the direction of magnetization of the initial ferromagnetic portion so that the initial ferromagnetic portion becomes the ferromagnetic portion 72 using laser light and an external magnetic field.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing 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 magnetic sensors, there is a demand for the magnetization direction of one free layer of two adjacent magnetoresistive elements to be different from the magnetization direction of the other free layer when there is no target magnetic field. To date, no consideration has been given to using a magnetic field generator consisting of a stack of antiferromagnetic and ferromagnetic layers to meet this demand.

[0007] The present invention has been made in consideration of such problems, and its purpose is to provide a method for manufacturing a magnetic sensor that can change the direction of magnetization of the free layer of at least one magnetoresistive effect element. [Means for solving the problem]

[0008] A magnetic sensor manufactured by the manufacturing method of the present invention comprises at least one magnetoresistive element including a magnetization fixed layer having magnetization including a component in a first direction and a magnetization whose direction is fixed, and a free layer having magnetization whose direction is changeable in response to a target magnetic field that is a magnetic field to be detected, and at least one magnetic field generator including a ferromagnetic part made of a ferromagnetic material and having magnetization including a component in a second direction different from the first direction and the magnetization whose direction is fixed, and an antiferromagnetic part made of an antiferromagnetic material and exchange-coupled with the ferromagnetic part, and configured to generate a magnetic field to be applied to the at least one magnetoresistive element. The manufacturing method of the magnetic sensor of the present invention includes the steps of forming at least one magnetoresistive element and forming at least one magnetic field generator. The step of forming at least one magnetic field generator includes a step of forming at least one initial magnetic field generator including an initial ferromagnetic portion and an antiferromagnetic portion, which will later become a ferromagnetic portion, and a step of fixing the direction of magnetization of the initial ferromagnetic portion using laser light and a first external magnetic field including a component in the first magnetic field direction so that the initial ferromagnetic portion becomes a ferromagnetic portion. [Effects of the Invention]

[0009] In the method for manufacturing a magnetic sensor according to the present invention, the magnetization direction of the initial ferromagnetic portion is fixed by using a laser beam and a first external magnetic field including a component in the first magnetic field direction, so that the initial ferromagnetic portion becomes a ferromagnetic portion, thereby achieving the effect of making it possible to change the magnetization direction of the free layer of at least one 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] 8 is a cross-sectional view showing a part of the cross section at the position indicated by line 8-8 in FIG. 7. [Figure 9] FIG. 2 is a plan view showing a step in the method for manufacturing the magnetic sensor according to the first embodiment of the present invention. [Figure 10] FIG. 10 is a plan view showing a step subsequent to FIG. 9. [Figure 11] FIG. 11 is a plan view showing a step subsequent to FIG. [Figure 12] FIG. 12 is a plan view showing a step subsequent to FIG. [Figure 13] FIG. 13 is a plan view showing a step subsequent to FIG. [Figure 14]5A to 5C are plan views showing second to fourth examples of the arrangement of resistor portions and the magnetization directions of ferromagnetic portions of a magnetic field generator in the first embodiment of the present invention. [Figure 15] 10A to 10D are plan views showing fifth to seventh examples of the arrangement of resistor portions and the magnetization directions of ferromagnetic portions of magnetic field generators in the first embodiment of the present invention. [Figure 16] 10A to 10C are plan views showing eighth to tenth examples of the arrangement of resistor portions and the magnetization directions of ferromagnetic portions of magnetic field generators in the first embodiment of the present invention. [Figure 17] 11A to 11C are plan views showing eleventh and twelfth examples of the arrangement of resistor portions and the magnetization directions of ferromagnetic portions of a magnetic field generator in the first embodiment of the present invention. [Figure 18] FIG. 3 is a cross-sectional view showing a main part of a first modified example of the magnetic sensor according to the first embodiment of the present invention. [Figure 19] FIG. 10 is a cross-sectional view showing a main part of a second modified example of the magnetic sensor according to the first embodiment of the present invention. [Figure 20] FIG. 10 is a cross-sectional view showing a main part of a third modified example of the magnetic sensor according to the first embodiment of the present invention. [Figure 21] 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 22] 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 23] FIG. 10 is a plan view showing a main part of a magnetic sensor according to a second embodiment of the present invention. [Figure 24] 24 is a cross-sectional view showing a part of the cross section at the position indicated by line 24-24 in FIG. 23. [Figure 25] FIG. 10 is a plan view showing a main part of a magnetic sensor according to a third 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] FIG. 10 is a plan view showing a step in a method for manufacturing a magnetic sensor according to a third embodiment of the present invention. [Figure 28]FIG. 28 is a plan view showing a step subsequent to FIG. 27. [Figure 29] FIG. 29 is a plan view showing a step subsequent to FIG. 28. [Figure 30] FIG. 30 is a plan view showing a step subsequent to FIG. 29. [Figure 31] FIG. 11 is a cross-sectional view showing a main part of a modified example of the magnetic sensor according to the third embodiment of the present invention. [Figure 32] FIG. 10 is a plan view showing a main part of a magnetic sensor according to a fourth embodiment of the present invention. [Figure 33] 33 is a cross-sectional view showing a part of a cross section taken along line 33-33 in FIG. 32. [Figure 34] FIG. 11 is a plan view showing a main part of a first modified example of the magnetic sensor according to the fourth embodiment of the present invention. [Figure 35] FIG. 13 is a cross-sectional view showing a main part of a second modified example of the magnetic sensor according to the fourth embodiment of the present invention. [Figure 36] FIG. 13 is a cross-sectional view showing a main part of a third modified example of the magnetic sensor according to the fourth embodiment of the present invention. [Figure 37] FIG. 10 is a perspective view showing a magnetic sensor system including a magnetic sensor according to a fifth embodiment of the present invention. [Figure 38] FIG. 10 is a circuit diagram showing a circuit configuration of a magnetic sensor according to a fifth embodiment of the present invention. [Figure 39] FIG. 10 is a perspective view showing a part of a magnetic sensor according to a fifth embodiment of the present invention. [Figure 40] FIG. 10 is a plan view showing a part of a magnetic sensor according to a fifth embodiment of the present invention. [Figure 41] FIG. 11 is a side view showing a part of a magnetic sensor according to a fifth embodiment of the present invention. [Figure 42] FIG. 10 is a plan view showing a main part of a magnetic sensor according to a fifth embodiment of the present invention. [Figure 43] 43 is a cross-sectional view showing a part of the cross section at the position indicated by line 43-43 in FIG. 42. [Figure 44] 44 is a cross-sectional view showing a part of the cross section at the position indicated by line 44-44 in FIG. 42. 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] The multiple MR elements 50A constituting the resistor unit R11 are arranged between the power supply port V1 and the output port E11 in terms of the circuit configuration. The multiple MR elements 50A constituting the resistor unit R12 are arranged between the output port E11 and the ground port G1 in terms of the circuit configuration. The multiple MR elements 50A constituting the resistor unit R13 are arranged between the output port E12 and the ground port G1 in terms of the circuit configuration. The multiple MR elements 50A constituting the resistor unit R14 are arranged between the power supply port V1 and the output port E12 in terms of the circuit configuration.

[0027] The multiple MR elements 50B constituting the resistor unit R21 are arranged between the power supply port V2 and the output port E21 in terms of the circuit configuration. The multiple MR elements 50B constituting the resistor unit R22 are arranged between the output port E21 and the ground port G2 in terms of the circuit configuration. The multiple MR elements 50B constituting the resistor unit R23 are arranged between the output port E22 and the ground port G2 in terms of the circuit configuration. The multiple MR elements 50B constituting the resistor unit R24 are arranged between the power supply port V2 and the output port E22 in terms of the circuit configuration.

[0028] 5 shows a first example of the arrangement of the resistor portions R11 to R14 on the substrate 30. In this example, the resistor portion R12 is arranged ahead of the resistor portion R11 in the X direction. The resistor portion R13 is arranged ahead of the resistor portion R12 in the Y direction. The resistor portion R14 is arranged ahead of the resistor portion R11 in the Y direction.

[0029] 6 shows a first example of the arrangement of the resistor portions R21 to R24 on the substrate 30. In this example, the resistor portion R22 is arranged ahead of the resistor portion R21 in the Y direction. The resistor portion R23 is arranged ahead of the resistor portion R22 in the -X direction. The resistor portion R24 is arranged ahead of the resistor portion R21 in the -X direction.

[0030] Other examples of the arrangement of the resistor portions R11 to R14 and R21 to R24 on the substrate 30 will be described later.

[0031] 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 Fig. 4, 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. This connects the plurality of MR elements 50A lined up in a line in a direction parallel to the X direction in series.

[0032] 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.

[0033] The above description of the connection relationship of the plurality of MR elements 50A basically also applies to the plurality of MR elements 50B of each of the resistance units R21 to R24. 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 of the connection relationship of the plurality of MR elements 50B.

[0034] The magnetic sensor 1 further includes a plurality of magnetic field generators 70A and a plurality of magnetic field generators 70B. The plurality of magnetic field generators 70A include 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, sandwiching 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. The bias magnetic field is part of the magnetic field generated by the magnetic field generator 70A, and contains a component parallel to the Y direction as its main component. At least the main component of the bias magnetic field is applied to the MR element 50A.

[0035] The multiple magnetic field generators 70B include multiple 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, sandwiching one MR element 50B between them. The two magnetic field generators 70B are configured to apply a bias magnetic field to the one MR element 50B located between them. The bias magnetic field is part of the magnetic field generated by the magnetic field generators 70B, and contains a component parallel to the X direction as its main component. At least the main component of the bias magnetic field is applied to the MR element 50B.

[0036] 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.

[0037] 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.

[0038] Next, the magnetization direction of the magnetization fixed layer and the direction of the bias magnetic field will be described with reference to FIGS. 3, 5, and 6. In FIG. 3, the multiple solid arrows drawn to overlap the resistor units R11 to R14 and R21 to R24 represent the magnetization direction of the magnetization fixed layer in each of the resistor units R11 to R14 and R21 to R24. In FIG. 5, the magnetization direction of the magnetization fixed layer in each of the resistor units R11 to R14 is represented by multiple arrows drawn to overlap the multiple MR elements 50A in each of the resistor units R11 to R14. In FIG. 6, the magnetization direction of the magnetization fixed layer in each of the resistor units R21 to R24 is represented by multiple arrows drawn to overlap the multiple MR elements 50B in each of the resistor units R21 to R24.

[0039] 3 and 5, the direction of the main component of magnetization of the magnetization fixed 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 fixed 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 direction of the easy axis of magnetization is parallel to the Y direction.

[0040] 3 and 6, 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 in which the direction of the easy axis of magnetization is parallel to the X direction.

[0041] In Fig. 3, arrows labeled M11, M12, M13, and M14 indicate the directions of the main components of the bias magnetic field generated by the multiple magnetic field generators 70A in the resistor units R11, R12, R13, and R14, respectively. In Fig. 5, the directions of the main components of the bias magnetic field generated by the multiple magnetic field generators 70A are indicated by multiple arrows drawn to overlap the multiple magnetic field generators 70A. The direction of the main component of the bias magnetic field in the resistor units R11 and R12 is the Y direction. The direction of the main component of the bias magnetic field in the resistor units R13 and R14 is the -Y direction.

[0042] 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.

[0043] In Fig. 3, arrows labeled M21, M22, M23, and M24 indicate the directions of the main components of the bias magnetic field generated by the multiple magnetic field generators 70B in the resistor units R21, R22, R23, and R24, respectively. In Fig. 6, the directions of the main components of the bias magnetic field generated by the multiple magnetic field generators 70B are indicated by multiple arrows drawn to overlap the multiple magnetic field generators 70B. 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.

[0044] 3, the multiple white arrows drawn to overlap the resistor units R21 to R24 respectively 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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 Figures 7 and 8. Figure 7 is a plan view showing a main part of the magnetic sensor 1. Figure 8 is a cross-sectional view showing a part of the cross section taken along line 8-8 in Figure 7.

[0049] 7 and 8, 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.

[0050] 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.

[0051] 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 FIG. 8 , 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. Each of the buffer layer 51 and cap layer 55 is formed of a nonmagnetic metal material such as Ru, Ta, Cu, or Cr. The free layer 54 is formed of a soft magnetic material such as CoFe, CoFeB, NiFe, or CoNiFe.

[0052] The magnetization fixed layer 52 includes an antiferromagnetic layer 521 disposed on the buffer layer 51 and a ferromagnetic layer 522 disposed on the antiferromagnetic layer 521. The antiferromagnetic layer 521 contacts the lower surface of the ferromagnetic layer 522 and generates exchange coupling between the antiferromagnetic layer 521 and the ferromagnetic layer 522 to fix the direction of magnetization of the ferromagnetic layer 522. The direction of magnetization of the magnetization fixed layer 52 is the same as the direction of magnetization of the ferromagnetic layer 522.

[0053] The antiferromagnetic layer 521 is made of an antiferromagnetic material such as IrMn or PtMn. The antiferromagnetic layer 73a of the antiferromagnetic part 73 of the magnetic field generator 70 and the antiferromagnetic layer 521 may contain at least one of the same elements. The ferromagnetic layer 522 is made of a ferromagnetic material containing one or more of Co, Fe, and Ni.

[0054] 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).

[0055] The magnetic sensor 1 further includes at least one magnetic field generator 70 configured to generate a bias magnetic field to be applied to the MR element 50. In particular, in this embodiment, the magnetic sensor 1 includes two magnetic field generators 70 arranged to sandwich the MR element 50. The MR element 50 is arranged between the two magnetic field generators 70 in the first direction D1.

[0056] In this embodiment, each of the two magnetic field generators 70 is disposed at a predetermined interval from the MR element 50. When viewed from the Z direction, each of the two magnetic field generators 70 does not overlap with the MR element 50.

[0057] Each of the two magnetic field generators 70 includes a ferromagnetic portion 72 made of a ferromagnetic material and an antiferromagnetic portion 73 made of an antiferromagnetic material. In this embodiment, the antiferromagnetic portion 73 is disposed on the ferromagnetic portion 72.

[0058] At least a portion of each of the two magnetic field generators 70 overlaps with the MR element 50 when viewed from the first direction D1. In this embodiment, the ferromagnetic part 72 includes a ferromagnetic layer 72a made of a ferromagnetic material. The ferromagnetic layer 72a is arranged so as to overlap with the MR element 50 when viewed from the first direction D1. The ferromagnetic layer 72a may be arranged so as to overlap with the entire free layer 54 when viewed from the first direction D1.

[0059] The ferromagnetic layer 72a is made of a ferromagnetic material containing one or more elements of Co, Fe, and Ni, such as CoFe, CoFeB, and CoNiFe.

[0060] The ferromagnetic portion 72 may include, instead of the ferromagnetic layer 72a, a laminate of multiple ferromagnetic layers, with adjacent layers made of different ferromagnetic materials. Examples of such a laminate include a Co layer, a CoFe layer, and a Co layer, and a Co 70 Fe 30 Layer and Co30 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.

[0061] The antiferromagnetic portion 73 includes an antiferromagnetic layer 73a made of an antiferromagnetic material. The antiferromagnetic layer 73a is disposed on the ferromagnetic layer 72a and is in contact with the ferromagnetic layer 72a. The antiferromagnetic layer 73a is made of an antiferromagnetic material such as IrMn or PtMn.

[0062] The ferromagnetic layer 72a has magnetization as a whole. The magnetization of the ferromagnetic layer 72a as a whole 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 72a. Hereinafter, the magnetization of the ferromagnetic layer 72a as a whole will simply be referred to as the magnetization of the ferromagnetic layer 72a. The antiferromagnetic layer 73a is in contact with the top surface of the ferromagnetic layer 72a and is exchange-coupled with the ferromagnetic layer 72a. This determines the direction of the magnetization of the ferromagnetic layer 72a.

[0063] In this embodiment, the ferromagnetic portion 72 is substantially entirely formed of the ferromagnetic layer 72a, and the antiferromagnetic portion 73 is substantially entirely formed of the antiferromagnetic layer 73a. The antiferromagnetic layer 73a is exchange-coupled with the ferromagnetic layer 72a, thereby causing the antiferromagnetic portion 73 to be exchange-coupled with the ferromagnetic portion 72. This determines the direction of magnetization of the ferromagnetic portion 72. The direction of magnetization of the ferromagnetic portion 72 coincides with the direction of magnetization of the ferromagnetic layer 72a. The ferromagnetic portion 72 and the antiferromagnetic portion 73 generate a bias magnetic field based on the magnetization of the ferromagnetic portion 72. The magnetic field generator 70 configured in this manner has high resistance to external disturbance magnetic fields.

[0064] The two magnetic field generators 70 cooperate to apply a bias magnetic field to the MR element 50. The magnetization direction of the ferromagnetic portion 72 of one of the two magnetic field generators 70 may be the same as the magnetization direction of the ferromagnetic portion 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 will be the same as the direction of the bias magnetic field generated by the other of the two magnetic field generators 70.

[0065] Each of the two magnetic field generators 70 further includes a buffer layer 71 disposed on the lower surface (-Z direction side) of the ferromagnetic layer 72a and a cap layer 74 disposed on the antiferromagnetic layer 73a. The buffer layer 71 and the cap layer 74 are made of a nonmagnetic metal material such as Ru, Ta, Cu, or Cr.

[0066] The magnetic sensor 1 further includes an insulating layer 32 made of an insulating material such as Al2O3 or SiO2 and arranged around the MR element 50 and the two magnetic field generators 70. The insulating layer 32 is interposed between the MR element 50 and the two magnetic field generators 70.

[0067] 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 insulating layer 32 and the two magnetic field generators 70. The insulating layer 33 is also interposed between the two magnetic field generators 70 and the lower electrode 61. The insulating layers 31 and 33 are formed of an insulating material such as Al2O3 or SiO2.

[0068] The upper electrode 62 is disposed on the MR element 50, the two magnetic field generators 70, and the insulating layer 32. The upper surface 50a of the MR element 50 and the upper surface of each of the two magnetic field generators 70, i.e., the upper surface of the cap layer 74, are in contact with the upper electrode 62. The magnetic sensor 1 further includes an insulating layer (not shown) made of an insulating material and disposed on the upper electrode 62.

[0069] Up to this point, the configuration of the MR element 50 and the magnetic field generator 70 has been described, focusing on one MR element 50. In this embodiment, the magnetic sensor 1 includes a plurality of MR elements 50. Therefore, the magnetic sensor 1 includes a plurality of magnetic field generators 70.

[0070] The multiple arrows drawn to overlap the multiple magnetic field generators 70A in FIG. 5 and the multiple arrows drawn to overlap the multiple magnetic field generators 70B in FIG. 6 essentially indicate the magnetization directions of the ferromagnetic portions 72 of the multiple magnetic field generators 70. Here, among the multiple magnetic field generators 70, the magnetic field generator 70 configured to apply a bias magnetic field to each of the multiple MR elements 50 of any resistor portion is referred to as the magnetic field generator 70 corresponding to that resistor portion. In the example shown in FIG. 5, the magnetization directions of the ferromagnetic portions 72 of the multiple magnetic field generators 70A corresponding to the resistor portions R11 and R12 are the Y direction. The magnetization directions of the ferromagnetic portions 72 of the multiple magnetic field generators 70A corresponding to the resistor portions R13 and R14 are the -Y direction.

[0071] 6, the magnetization direction of the ferromagnetic parts 72 of the magnetic field generators 70B corresponding to the resistors R21 and R22 is the −X direction, and the magnetization direction of the ferromagnetic parts 72 of the magnetic field generators 70B corresponding to the resistors R23 and R24 is the X direction.

[0072] 5 and 6 show a first example of the magnetization direction of the ferromagnetic part 72 of the magnetic field generator 70. Other examples of the magnetization direction of the ferromagnetic part 72 of the magnetic field generator 70 will be described later.

[0073] Next, a method for manufacturing the magnetic sensor 1 according to this embodiment will be described. The method for manufacturing the magnetic sensor 1 includes a step of forming at least one MR element 50 and a step of forming at least one magnetic field generator 70. In this embodiment, in particular, the step of forming at least one MR element 50 is a step of forming a plurality of MR elements 50, and the step of forming at least one magnetic field generator 70 is a step of forming a plurality of magnetic field generators 70.

[0074] First, a process for forming the plurality of MR elements 50 will be described. In the process for forming the plurality of MR elements 50, first, a plurality of initial MR elements that will later become the plurality of MR elements 50 are formed. Each of the plurality of initial MR elements includes an initial magnetization fixed layer that 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. The initial magnetization fixed layer includes an antiferromagnetic layer 521 and a ferromagnetic layer 522.

[0075] Next, the magnetization direction of the initial magnetization pinned layer is pinned in the predetermined direction using laser light and an external magnetic field containing a component in the predetermined direction. Hereinafter, this process will be referred to as the process of pinning the magnetization direction of the initial magnetization pinned layer or the process of pinning the magnetization direction of the magnetization pinned layer 52. The predetermined direction may coincide with the magnetization direction of the magnetization pinned layer 52. For example, for the initial MR elements that will later become the MR elements 50A constituting 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. The laser light is irradiated so that the temperature of the initial MR elements irradiated with the laser light is equal to or higher than the blocking temperature of the antiferromagnetic layer 521 of the initial magnetization pinned layer. The temperature of the initial MR elements can be adjusted, for example, by the intensity and pulse width of the laser light. After the laser light irradiation, when the temperature of the initial MR elements drops below the blocking temperature, the magnetization direction of the initial magnetization pinned layer is pinned in the X direction. As a result, the initial magnetization fixed layer becomes the magnetization fixed layer 52 .

[0076] Furthermore, in the initial MR elements that will later become the MR elements 50A that constitute the resistor units R12, R14 of the first detection circuit 10, the magnetization direction of the initial magnetization fixed 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. The magnetization direction of the magnetization fixed layer 52 of each of the MR elements 50B that constitute each of the resistor units R21 to R24 of the second detection circuit 20 is also fixed in the same manner as the magnetization fixed layer 52 of each of the MR elements 50A.

[0077] The MR element 50 is completed by fixing the direction of magnetization of the magnetization fixed layer 52 and then patterning the laminated film by etching so that two side surfaces 50c and two side surfaces 50d are formed in the laminated film. Note that, after forming the two side surfaces 50c and two side surfaces 50d in the laminated film, a step of fixing the direction of magnetization of the initial magnetization fixed layer may be performed.

[0078] Next, the process of forming the multiple magnetic field generators 70 will be described. First, focusing on one MR element 50, an overview of the process of forming two magnetic field generators 70 will be described. First, a photoresist mask is formed on the MR element 50 and the insulating layer 32. Next, the insulating layer 32 is etched. Next, with the photoresist mask remaining, the insulating layer 33 and two initial magnetic field generators 70P, which will later become the two magnetic field generators 70, are formed in this order. Each of the two initial magnetic field generators 70P includes an initial ferromagnetic portion, which will later become the ferromagnetic portion 72, a buffer layer 71, an antiferromagnetic portion 73, and a cap layer 74. The buffer layer 71, the initial ferromagnetic portion, the antiferromagnetic portion 73, and the cap layer 74 are stacked in this order. Next, the photoresist mask is removed.

[0079] Next, the magnetization direction of the initial ferromagnetic portion is fixed in the predetermined direction using a laser beam and an external magnetic field containing a component in a predetermined direction. Hereinafter, this process will be referred to as the process of fixing the magnetization direction of the initial ferromagnetic portion or the process of fixing the magnetization direction of the ferromagnetic portion 72. The predetermined direction may coincide with the magnetization direction of the ferromagnetic portion 72. The method of fixing the magnetization direction of the initial ferromagnetic portion is similar to the method of fixing the magnetization direction of the initial magnetization fixed layer. That is, while applying an external magnetic field, laser beams are irradiated onto each of the two initial magnetic field generators 70P. The laser beams are irradiated so that the temperature of the two initial magnetic field generators 70P irradiated with the laser beam reaches or exceeds the blocking temperature of the antiferromagnetic portion 73. The temperature of the two initial magnetic field generators 70P can be adjusted, for example, by the intensity and pulse width of the laser beam. After the laser beam irradiation, when the temperature of the two initial magnetic field generators 70P drops below the blocking temperature, the magnetization direction of the initial ferromagnetic portion is fixed in the predetermined direction. As a result, the initial ferromagnetic layer becomes a ferromagnetic portion 72, and the two initial magnetic field generators 70P become two magnetic field generators 70.

[0080] The intensity of the laser light used to fix the magnetization direction of the initial ferromagnetic portion may be smaller than the intensity of the laser light used to fix the magnetization direction of the initial magnetization fixed layer. Furthermore, the intensity of the laser light used to fix the magnetization direction of the initial ferromagnetic portion is preferably an intensity that suppresses a change in the magnetoresistance change rate, which is the ratio of magnetoresistance change to the resistance of the MR element 50.

[0081] Furthermore, if each of the two magnetic field generators 70 has multiple side surfaces formed by etching, a step of fixing the magnetization direction of the initial ferromagnetic portion may be performed before forming at least one of the multiple side surfaces, or a step of fixing the magnetization direction of the initial ferromagnetic portion may be performed after forming at least one of the multiple side surfaces.

[0082] In this embodiment, the ferromagnetic portions 72 are essentially ferromagnetic layers 72a. Therefore, the initial ferromagnetic portions are essentially initial ferromagnetic layers that will later become ferromagnetic layers 72a. The process of forming the multiple magnetic field generators 70 can be explained by replacing the ferromagnetic portions 72 and the initial ferromagnetic portions with the ferromagnetic layers 72a and the initial ferromagnetic layers, respectively.

[0083] Next, the process of fixing the magnetization direction of the initial ferromagnetic layer will be described in more detail with reference to FIGS. 9 to 13. FIGS. 9 to 13 schematically show the four resistor units R11 to R14 of the first detection circuit 10 or the four resistor units R21 to R24 of the second detection circuit 20. In FIGS. 9 to 13, reference character R1 indicates a resistor unit corresponding to the resistor unit R11 or R21. Reference character R2 indicates a resistor unit corresponding to the resistor unit R12 or R22. Reference character R3 indicates a resistor unit corresponding to the resistor unit R13 or R23. Reference character R4 indicates a resistor unit corresponding to the resistor unit R14 or R24.

[0084] 9 to 13, one MR element 50 is shown as a representative of the multiple MR elements 50 in each of the resistor sections R1 to R4. Also, a plurality of initial magnetic field generators 70P or multiple magnetic field generators 70 are shown as a representative of the multiple initial magnetic field generators 70P or multiple magnetic field generators 70, arranged to sandwich one MR element 50 in each of the resistor sections R1 to R4. Also, FIGS. 9 to 13 show a first direction D1 and a second direction D2. The same notations as those in FIGS. 9 to 13 are used in the following explanations in multiple figures similar to those in FIGS. 9 to 13.

[0085] FIG. 9 shows the resistor portions R1 to R4 after the formation of the initial magnetic field generators 70P. FIG. 10 shows the next step. In this step, a laser beam is selectively applied to the initial magnetic field generators 70P corresponding to the resistor portions R1 and R2 while a magnetic field component MF1 is applied to the magnetic sensor 1 in one direction parallel to the first direction D1 (a bottom-to-top direction in FIG. 10). After the laser beam is applied, the magnetization direction of the initial ferromagnetic layer of each of the irradiated initial magnetic field generators 70P is fixed in the same direction as the magnetic field component MF1. As a result, as shown in FIG. 11, the initial magnetic field generators 70P irradiated with the laser beam become a plurality of magnetic field generators 70.

[0086] The laser light may be selectively applied to the multiple initial magnetic field generators 70P using, for example, a mask 101. The mask 101 has multiple openings 101a that expose some or all of the multiple initial magnetic field generators 70P corresponding to the resistor portions R1 and R2. The multiple MR elements 50 of the resistor portions R1 to R4 and the multiple initial magnetic field generators 70P corresponding to the resistor portions R3 and R4 are covered by the mask 101. The laser light is applied to some or all of the multiple initial magnetic field generators 70P through the multiple openings 101a. When the laser light is applied to some of the multiple initial magnetic field generators 70P, the magnetic sensor 1 is moved using, for example, a stage, and the laser light is applied to all of the initial magnetic field generators 70P corresponding to the resistor portions R1 and R2.

[0087] Although the laser light is not irradiated onto the MR elements 50, the temperatures of the MR elements 50 may also rise during irradiation of the laser light. However, the temperatures of the MR elements 50 do not become higher than the blocking temperature of the antiferromagnetic layer 521.

[0088] 12 shows the next step. In this step, a laser beam is selectively applied to the initial magnetic field generators 70P corresponding to the resistors R3 and R4 while a magnetic field component MF2 in another direction parallel to the first direction D1 (a direction from top to bottom in FIG. 12) is applied to the magnetic sensor 1. After the laser beam is applied, the magnetization direction of the initial ferromagnetic layer of each of the irradiated initial magnetic field generators 70P is fixed in the same direction as the magnetic field component MF2. As a result, the initial magnetic field generators 70P irradiated with the laser beam become a plurality of magnetic field generators 70, as shown in FIG. 13.

[0089] Similar to the process shown in FIG. 10 , the laser light may be selectively applied to the multiple initial magnetic field generators 70P using, for example, a mask 102. The mask 102 has multiple openings 102a that expose some or all of the multiple initial magnetic field generators 70P corresponding to the resistor portions R3 and R4. The multiple MR elements 50 of the resistor portions R1 to R4 and the multiple magnetic field generators 70 corresponding to the resistor portions R1 and R2 are covered by the mask 102. The laser light is applied to some or all of the multiple initial magnetic field generators 70P through the multiple openings 102a. When the laser light is applied to some of the multiple initial magnetic field generators 70P, the magnetic sensor 1 is moved using, for example, a stage, and the laser light is applied to all of the initial magnetic field generators 70P corresponding to the multiple MR elements 50 of the resistor portions R3 and R4.

[0090] Although the laser light is not irradiated onto the resistors R1 and R2, the temperatures of the magnetic field generators 70 corresponding to the resistors R1 and R2 may also rise during irradiation with the laser light. However, the temperatures of the magnetic field generators 70 corresponding to the resistors R1 and R2 do not exceed the blocking temperature of the antiferromagnetic portion 73.

[0091] The method for manufacturing the magnetic sensor 1 may further include a step of performing an annealing process in which a laminate including a plurality of MR elements 50, each having a fixed magnetization direction in the magnetization fixed layer 52, and a plurality of magnetic field generators 70, each having a fixed magnetization direction in the ferromagnetic portion 72, is heated at a predetermined temperature. The annealing process may be performed using, for example, an electric furnace. By performing the annealing process, the magnetization directions of the magnetization fixed layer 52 and the ferromagnetic portion 72 can be stabilized. As a result, fluctuations in the characteristics of the magnetic sensor 1 after the magnetic sensor 1 is completed can be suppressed.

[0092] Next, the effects of the magnetic sensor 1 according to this embodiment will be described. As shown in FIG. 5 , in this embodiment, some of the MR elements 50A in the resistor section R11 and some of the MR elements 50A in the resistor section R14 are adjacent to each other without any other MR elements 50A capable of detecting the magnetoresistive effect interposed therebetween. Here, a set of some of the MR elements 50A in the resistor section R11 and some of the magnetic field generators 70A that apply a bias magnetic field to some of the MR elements 50A in the resistor section R11 is referred to as a first set. Also, a set of some of the MR elements 50A in the resistor section R14 and some of the magnetic field generators 70A that apply a bias magnetic field to some of the MR elements 50A in the resistor section R14 is referred to as a second set. There are no other sets of MR elements 50A and other magnetic field generators 70 that can detect the magnetoresistive effect interposed between the first set and the second set.

[0093] The MR element 50, to which any electrode is connected and whose resistance value can be detected, corresponds to another MR element 50 capable of detecting the magnetoresistive effect. On the other hand, examples of MR elements that do not correspond to the MR element 50 capable of detecting the magnetoresistive effect include the following first to third MR elements. The first MR element is an MR element to which no electrode is connected and whose resistance value cannot be detected. The second MR element is a CIP (Current-In-Plane) type GMR element in which a current flows in a direction substantially parallel to the surface of each layer constituting the MR element, and is a GMR element in which a thick conductive film is formed on the GMR element. The third MR element is an MR element whose resistance value does not change even when the direction or strength of the applied magnetic field changes due to an imperfect configuration of the MR element. Examples of such MR elements include a TMR element or a GMR element in which the magnetization direction of the magnetization pinned layer is not fixed.

[0094] In the magnetic sensor 1, there may be a need to make the magnetization direction of the free layer 54 in the first group different from the magnetization direction of the free layer 54 in the second group when there is no target magnetic field. In contrast, in this embodiment, the magnetization direction of the ferromagnetic portion 72 of the magnetic field generator 70A in the first group is made different from the magnetization direction of the ferromagnetic portion 72 of the magnetic field generator 70A in the second group. In particular, in this embodiment, the magnetization direction of the ferromagnetic portion 72 of the magnetic field generator 70A in the first group is opposite to the magnetization direction of the ferromagnetic portion 72 of the magnetic field generator 70A in the second group. Therefore, the direction of the main component of the bias magnetic field generated by the magnetic field generator 70A in the first group is also opposite to the direction of the main component of the bias magnetic field generated by the magnetic field generator 70A in the second group. As a result, according to this embodiment, when there is no target magnetic field, the magnetization direction of the free layer 54 in the first set and the magnetization direction of the free layer 54 in the second set can be made different from each other.

[0095] As shown in FIG. 5 , in this embodiment, some of the MR elements 50A in the resistor section R12 and some of the MR elements 50A in the resistor section R13 are adjacent to each other without any other MR elements 50A capable of detecting the magnetoresistive effect. A group consisting of some of the MR elements 50A in the resistor section R12 and some of the magnetic field generators 70A that apply a bias magnetic field to some of the MR elements 50A in the resistor section R12 is referred to as a third group. A group consisting of some of the MR elements 50A in the resistor section R13 and some of the magnetic field generators 70A that apply a bias magnetic field to some of the MR elements 50A in the resistor section R13 is referred to as a fourth group. There are no other MR elements 50A or other magnetic field generators 70 that can detect the magnetoresistive effect between the third group and the fourth group. The third group is adjacent to one of the first group and the second group at a predetermined interval. The fourth set is adjacent to the other of the first set and the second set at a predetermined interval.

[0096] The above description of the magnetic field generators 70A corresponding to the resistors R11 and R14 also applies to the magnetic field generators 70A corresponding to the resistors R12 and R13. Moreover, the above description of the resistors R11 to R14 also applies to the resistors R21 to R24.

[0097] Although not shown, one or two of the resistance sections R11 to R14 (hereinafter referred to as first resistance sections) are adjacent to one or two of the resistance sections R21 to R24 (hereinafter referred to as second resistance sections). In the magnetic sensor 1, when there is no target magnetic field, there may be a demand for the magnetization direction of the free layer 54 of each of the multiple MR elements 50A in the first resistance section to be different from the magnetization direction of the free layer 54 of each of the multiple MR elements 50B in the second resistance section.

[0098] In this embodiment, the magnetization direction of the ferromagnetic portions 72 of the plurality of magnetic field generators 70A corresponding to the first resistance section is made different from the magnetization direction of the ferromagnetic portions 72 of the plurality of magnetic field generators 70B corresponding to the second resistance section. In this embodiment, the magnetization direction of the ferromagnetic portions 72 of the plurality of magnetic field generators 70A corresponding to the first resistance section is perpendicular to the magnetization direction of the ferromagnetic portions 72 of the plurality of magnetic field generators 70B corresponding to the second resistance section. Therefore, the direction of the main component of the bias magnetic field generated by the plurality of magnetic field generators 70A corresponding to the first resistance section is also perpendicular to the direction of the main component of the bias magnetic field generated by the plurality of magnetic field generators 70B corresponding to the second resistance section. This allows the magnetization direction of the free layer 54 of each of the plurality of MR elements 50A in the first resistance section to be made different from the magnetization direction of the free layer 54 of each of the plurality of MR elements 50B in the second resistance section when there is no target magnetic field.

[0099] Next, second to twelfth examples of the arrangement of the resistor portions R11 to R14 and R21 to R24 on the substrate 30 and the magnetization direction of the ferromagnetic portion 72 of the magnetic field generator 70 will be described.

[0100] FIG. 14(a) shows a second example. In FIG. 14(a), the resistor sections R11 to R14 and R21 to R24 are represented using the resistor sections R1 to R4 shown in FIGS. 9 to 13. In the second example, the arrangement of the resistor sections R1 to R4 is the same as the first example of the arrangement of the resistor sections R11 to R14 shown in FIG. 5 and the first example of the arrangement of the resistor sections R21 to R24 shown in FIG. 6. That is, FIG. 14(a) shows that the arrangement of the resistor sections R1 to R4 is the same as the arrangement of the resistor sections R11 to R14 shown in FIG. 5 and the arrangement of the resistor sections R21 to R24 shown in FIG. 6.

[0101] 14(a), multiple arrows drawn to overlap the resistor units R1 to R4 represent the magnetization direction of the magnetization fixed layer 52 in each of the resistor units R1 to R4. Fig. 14(a) shows that the magnetization direction of the magnetization fixed layer 52 in each of the resistor units R1 to R4 is the same as the magnetization direction of the magnetization fixed layer in each of the resistor units R11 to R14 shown in Fig. 5 and the magnetization direction of the magnetization fixed layer in each of the resistor units R21 to R24 shown in Fig. 6. That is, as described above, the magnetization direction of the magnetization fixed layer 52 in each of the resistor units R11 and R13 is the X direction, and the direction of the main component of the magnetization of the magnetization fixed layer in each of the resistor units R21 and R23 is the Y direction. In Figure 14(a), the magnetization direction of the magnetization fixed layer 52 in each of the resistance sections R1, R3 corresponding to the resistance sections R11, R13 or the resistance sections R21, R23 is represented by an arrow in one direction parallel to the second direction D2 (in Figure 14(a), the direction from the resistance section R1 to the resistance section R2).

[0102] As described above, the magnetization direction of the magnetization fixed layer in each of the resistance units R12 and R14 is the −X direction, and the magnetization direction of the magnetization fixed layer in each of the resistance units R22 and R24 is the −Y direction. In Fig. 14(a), the magnetization direction of the magnetization fixed layer 52 in each of the resistance units R2 and R4 corresponding to the resistance units R12 and R14 or the resistance units R22 and R24 is represented by an arrow in another direction parallel to the second direction D2 (the direction from the resistance unit R2 to the resistance unit R1 in Fig. 14(a)).

[0103] 14(a), the multiple arrows drawn to overlap the multiple magnetic field generators 70 respectively represent the magnetization direction of the ferromagnetic portions 72 of the multiple magnetic field generators 70. In the second example, the magnetization direction of each of the ferromagnetic portions 72 of the multiple magnetic field generators 70 corresponding to the resistors R1 and R4 is in one direction parallel to the first direction D1 (the direction from resistor R4 to resistor R1 in FIG. 14(a)). That is, the magnetization direction of each of the ferromagnetic portions 72 of the multiple magnetic field generators 70A corresponding to resistors R11 and R14 is the -Y direction, and the magnetization direction of each of the ferromagnetic portions 72 of the multiple magnetic field generators 70B corresponding to resistors R21 and R24 is the X direction.

[0104] In the second example, the magnetization direction of each ferromagnetic portion 72 of the plurality of magnetic field generators 70 corresponding to the resistance portions R2 and R3 is another direction parallel to the first direction D1 (the direction from the resistance portion R2 to the resistance portion R3 in FIG. 14(a)). That is, the magnetization direction of each ferromagnetic portion 72 of the plurality of magnetic field generators 70A corresponding to the resistance portions R12 and R13 is the Y direction, and the magnetization direction of each ferromagnetic portion 72 of the plurality of magnetic field generators 70B corresponding to the resistance portions R22 and R23 is the −X direction.

[0105] As described above, in the second example, the arrangement of the resistance sections R1 to R4 is the same as in the first example shown in Figures 5 and 6, but the magnetization direction of the ferromagnetic section 72 of the magnetic field generator 70 is different from that in the first example.

[0106] 14(a) that will be used in the following description, the arrangement of the resistors R1 to R4 (resistors R11 to R14, R21 to R24) and the magnetization direction of the ferromagnetic portion 72 of the magnetic field generator 70 will be represented in the same manner as in Fig. 14(a). In the following description, the correspondence between the resistors R1 to R4 and the resistors R11 to R14, R21 to R24, and the correspondence between the first and second directions D1, D2 and the X and Y directions will be omitted.

[0107] Figure 14(b) shows a third example. In the third example, the magnetization direction of the ferromagnetic portion 72 of the magnetic field generator 70 is the same as in the first example shown in Figures 5 and 6, but the arrangement of the resistors R3 and R4 is different from that of the first example. That is, in the third example, the resistors R3 and R4 are each arranged ahead of the resistors R1 and R2 in one direction parallel to the first direction D1.

[0108] FIG. 14(c) shows a fourth example. In the fourth example, the arrangement of the resistors R1 to R4 and the magnetization direction of the ferromagnetic portions 72 of the magnetic field generators 70 corresponding to the resistors R1 and R3 are the same as those in the third example shown in FIG. 14(b). However, the magnetization direction of the ferromagnetic portions 72 of the magnetic field generators 70 corresponding to the resistors R2 and R4 is different from that in the third example. That is, in the fourth example, the magnetization direction of the ferromagnetic portions 72 of the magnetic field generators 70 corresponding to the resistor R2 is the same as that of the ferromagnetic portions 72 of the magnetic field generators 70 corresponding to the resistor R3, which is opposite to that in the third example. Furthermore, the magnetization direction of the ferromagnetic portions 72 of the magnetic field generators 70 corresponding to the resistor R4 is the same as that of the ferromagnetic portions 72 of the magnetic field generators 70 corresponding to the resistor R1, which is opposite to that in the third example.

[0109] Figure 15(a) shows a fifth example. In the fifth example, the magnetization direction of the ferromagnetic portion 72 of the magnetic field generator 70 is the same as in the first example shown in Figures 5 and 6, but the arrangement of the resistance portions R1 to R4 is different from that of the first example. That is, in the fifth example, the resistance portions R1 to R4 are arranged in this order in one direction parallel to the second direction D2.

[0110] Figure 15(b) shows a sixth example, in which the arrangement of the resistors R1 to R4 is the same as in the fifth example shown in Figure 15(a), and the magnetization direction of the ferromagnetic part 72 of the magnetic field generator 70 is the same as in the fourth example shown in Figure 14(c).

[0111] Figure 15(c) shows a seventh example. In the seventh example, the arrangement of the resistors R1 and R2 and the direction of magnetization of the ferromagnetic portion 72 of the magnetic field generator 70 are the same as those in the fifth example shown in Figure 15(a), but the arrangement of the resistors R3 and R4 is different from that in the fifth example. That is, in the seventh example, the resistor R4 is arranged in a position sandwiching the resistor R2 between itself and the resistor R1 in the second direction D2. The resistor R3 is arranged in a position sandwiching the resistor R4 between itself and the resistor R2 in the second direction D2.

[0112] Figure 16(a) shows an eighth example, in which the arrangement of the resistance portions R1 to R4 is the same as that of the seventh example shown in Figure 15(c), and the magnetization direction of the ferromagnetic portion 72 of the magnetic field generator 70 is the same as that of the sixth example shown in Figure 15(b).

[0113] FIG. 16(b) shows a ninth example. In the ninth example, the arrangement of the resistors R1 and R4 and the magnetization direction of the ferromagnetic portion 72 of the magnetic field generator 70 are the same as those in the fifth example shown in FIG. 15(a), but the arrangement of the resistors R2 and R3 is different from that in the fifth example. That is, in the ninth example, the resistors R2 and R3 are arranged between the resistors R1 and R4. The resistor R2 is arranged closer to the resistor R4 than the resistor R1. The resistor R3 is arranged closer to the resistor R1 than the resistor R4.

[0114] Figure 16(c) shows a tenth example. In the tenth example, the magnetization direction of the ferromagnetic portion 72 of the magnetic field generator 70 is the same as in the sixth example shown in Figure 15(b), but the arrangement of the resistance portions R1 to R4 is different from that of the sixth example. That is, in the tenth example, the resistance portions R1 to R4 are arranged in one direction parallel to the second direction D2 in the order of resistance portion R1, resistance portion R3, resistance portion R4, and resistance portion R2.

[0115] Figure 17(a) shows an eleventh example. In the eleventh example, the arrangement of the resistance portions R1 to R4 is the same as that of the ninth example shown in Figure 16(b), and the magnetization direction of the ferromagnetic portion 72 of the magnetic field generator 70 is the same as that of the sixth example shown in Figure 15(b).

[0116] Figure 17(b) shows a twelfth example, in which the arrangement of the resistance portions R1 to R4 is the same as that of the tenth example shown in Figure 16(c), and the magnetization direction of the ferromagnetic portion 72 of the magnetic field generator 70 is the same as that of the fifth example shown in Figure 15(a).

[0117] [Variations] Next, first to fifth 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. 18. FIG. 18 is a cross-sectional view showing a main part of the first modified example of the magnetic sensor 1. In the first modified example, the magnetization pinned layer 52 of the MR element 50 does not include the antiferromagnetic layer 521 shown in FIG. 8. In the first modified example, the magnetization pinned layer 52 may include a soft magnetic layer made of a ferromagnetic material containing one or more elements of Co, Fe, and Ni. In this case, the coercivity of the magnetization pinned layer 52 may be increased by using a specific material such as Ta for the buffer layer 51 and reducing the thickness of the soft magnetic layer. Alternatively, the magnetization pinned layer 52 may be made of a hard magnetic material containing elements such as Pt, Sm, and Nd.

[0118] In the process of fixing the magnetization direction of the magnetization fixed layer 52 in the first modification, the magnetization direction of the initial magnetization fixed layer is fixed in the predetermined direction using laser light and an external magnetic field including a component in a predetermined direction. For the initial MR elements that will later become the MR elements 50A constituting the resistor units R11 and R13 of the first detection circuit 10, laser light is irradiated to the initial MR elements while applying an external magnetic field in the X direction. The laser light irradiation reduces the coercivity of the magnetization fixed layer 52 of each of the initial MR elements, causing the magnetization direction of the magnetization fixed layer 52 to tilt toward the X direction. After the laser light irradiation, 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. The coercivity of each of the magnetization fixed layers 52 of the initial MR elements that are not irradiated with laser light is maintained at a magnitude that prevents the magnetization direction of the magnetization fixed layer 52 from tilting due to the external magnetic field.

[0119] Furthermore, in the initial MR elements that will later become the MR elements 50A that constitute the resistor units R12, R14 of the first detection circuit 10, the magnetization direction of the initial magnetization fixed 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. The magnetization direction of the magnetization fixed layer 52 of each of the MR elements 50B that constitute each of the resistor units R21 to R24 of the second detection circuit 20 is also fixed in the same manner as the magnetization fixed layer 52 of each of the MR elements 50A.

[0120] Next, a second modified example will be described with reference to FIG. 19. FIG. 19 is a cross-sectional view showing a main portion of the second modified example of the magnetic sensor 1. In the second modified example, an antiferromagnetic layer 73a, a ferromagnetic layer 72a, and a cap layer 74 are sequentially disposed on a buffer layer 71. In the second modified example, the antiferromagnetic layer 73a is in contact with the lower surface of the ferromagnetic layer 72a and exchange-coupled with the ferromagnetic layer 72a. This defines the direction of magnetization of the ferromagnetic layer 72a.

[0121] Next, a third modified example will be described with reference to FIG. 20. FIG. 20 is a cross-sectional view showing a main part of the third modified example of the magnetic sensor 1. In the third modified example, the antiferromagnetic part 73 includes an antiferromagnetic layer 73b in addition to an antiferromagnetic layer 73a. The antiferromagnetic layer 73b is disposed between the buffer layer 71 and the ferromagnetic layer 72a. The antiferromagnetic layer 73b is formed of an antiferromagnetic material such as IrMn or PtMn.

[0122] The antiferromagnetic layer 73b is in contact with the lower surface of the ferromagnetic layer 72a and exchange-coupled to the ferromagnetic layer 72a. As described above, the antiferromagnetic layer 73a is in contact with the upper surface of the ferromagnetic layer 72a and exchange-coupled to the ferromagnetic layer 72a. In the third modification, the antiferromagnetic layers 73a and 73b are exchange-coupled to the ferromagnetic layer 72a, thereby defining the direction of magnetization of the ferromagnetic layer 72a.

[0123] Next, a fourth modified example will be described with reference to FIG. 21. FIG. 21 is a cross-sectional view showing a main portion of the fourth modified example of the magnetic sensor 1. In the fourth modified example, the ferromagnetic part 72 includes a ferromagnetic layer 72b in addition to the ferromagnetic layer 72a. The ferromagnetic layer 72b is disposed between the buffer layer 71 and the ferromagnetic layer 72a. The ferromagnetic layer 72b is formed of a ferromagnetic material containing one or more elements of Co, Fe, and Ni. In the fourth modified example, the ferromagnetic layer 72b has a magnetization in the same direction as the magnetization of the ferromagnetic layer 72a.

[0124] In a fourth modification, the ferromagnetic layer 72a may be formed of a ferromagnetic material capable of increasing the exchange coupling energy with the antiferromagnetic layer 73a, and the ferromagnetic layer 72b may be formed of a ferromagnetic material having a higher saturation magnetic flux density than the ferromagnetic material constituting the ferromagnetic layer 72a. In this case, the exchange coupling energy between the ferromagnetic part 72 consisting of the ferromagnetic layers 72a and 72b and the antiferromagnetic layer 73a 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 72a is Co. 70 Fe 30 An example of the ferromagnetic layer 72b is a Co layer. 30 Fe 70 The Co layer is 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.

[0125] Next, a fifth modified example will be described with reference to FIG. 22. FIG. 22 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 ferromagnetic part 72 includes a ferromagnetic layer 72b in addition to a ferromagnetic layer 72a. The ferromagnetic layer 72b is disposed between the buffer layer 71 and the ferromagnetic layer 72a. The ferromagnetic layer 72b is made of a ferromagnetic material containing one or more elements of Co, Fe, and Ni. The ferromagnetic layers 72a and 72b may be made of the same ferromagnetic material or different ferromagnetic materials.

[0126] In the fifth modification, the magnetic field generator 70 further includes a non-magnetic layer 75 disposed between the ferromagnetic layers 72 a and 72 b. The non-magnetic layer 75 is made of a non-magnetic metal material such as Ru.

[0127] In a fifth modification, the ferromagnetic layers 72a and 72b may be ferromagnetically exchange-coupled via a nonmagnetic layer 75 so that their magnetizations are in the same direction. In this case, the ferromagnetic layers 72a and 72b have magnetizations in the same direction. The thickness of the nonmagnetic layer 75 is set so as not to eliminate the exchange coupling between the ferromagnetic layers 72a and 72b. By providing the nonmagnetic layer 75, it is possible to adjust the coercivity of the ferromagnetic part 72 and the surface roughness of the base of the ferromagnetic layer 72a.

[0128] Alternatively, the ferromagnetic layers 72a and 72b may be antiferromagnetically exchange-coupled via the nonmagnetic layer 75 by RKKY interaction. In this case, the magnetization directions of the ferromagnetic layers 72a and 72b are opposite to each other. The magnetization direction of the ferromagnetic portion 72 is the same as that of the ferromagnetic layer 72a. When the ferromagnetic layers 72a and 72b are antiferromagnetically exchange-coupled, the net moment of the ferromagnetic portion 72 is reduced. Therefore, the Zeeman energy of the ferromagnetic portion 72, which is the energy generated when an external magnetic field acts on the magnetic moment, is reduced. As a result, even when an external magnetic field is applied, the magnetization direction of the ferromagnetic portion 72 is less likely to tilt than when the Zeeman energy is large.

[0129] The thickness of the nonmagnetic layer 75 is set so that the magnetization directions of the ferromagnetic layers 72a and 72b due to the RKKY interaction are in the expected directions, and the strength of the exchange coupling due to the RKKY interaction is the expected strength.

[0130] [Second embodiment] Next, a second embodiment of the present invention will be described with reference to Fig. 23 and Fig. 24. Fig. 23 is a plan view showing a main part of a magnetic sensor according to this embodiment. Fig. 24 is a cross-sectional view showing a part of a cross section taken along line 24-24 in Fig. 23.

[0131] The magnetic sensor 1 according to this embodiment includes a plurality of magnetic field generators 700 instead of the plurality of magnetic field generators 70 in the first embodiment. The functions of the plurality of magnetic field generators 700 and the positional relationship of the plurality of magnetic field generators 700 with respect to the plurality of MR elements 50 are the same as those in the first embodiment.

[0132] The configuration of the magnetic field generator 700 will be described below, focusing on one MR element 50. The magnetic sensor 1 according to this embodiment includes two magnetic field generators 700 arranged to sandwich the MR element 50. Each of the two magnetic field generators 700 includes a ferromagnetic portion 712 made of a ferromagnetic material.

[0133] The ferromagnetic part 712 includes a ferromagnetic layer 712a made of a ferromagnetic material. The ferromagnetic layer 712a is arranged so as to overlap the MR element 50 when viewed from the first direction D1. In particular, in this embodiment, the ferromagnetic layer 712a is arranged so as to overlap the entire free layer 54 when viewed from the first direction D1. The MR element 50 is arranged between two ferromagnetic layers 712a arranged at a predetermined interval in the first direction D1. The ferromagnetic layer 712a may be formed of, for example, the same material as the ferromagnetic layer 72a in the first embodiment.

[0134] Each of the two magnetic field generators 700 further includes a buffer layer 711 disposed on the lower surface side of the ferromagnetic portion 712. The buffer layer 711 may be formed of, for example, the same material as the buffer layer 71 in the first embodiment.

[0135] The magnetic sensor 1 according to this embodiment further includes an underlayer 713 disposed on the MR element 50, the two ferromagnetic layers 712a, and the insulating layer 32, an antiferromagnetic layer 714 disposed on the underlayer 713, and a cap layer 715 disposed on the antiferromagnetic layer 714. The antiferromagnetic layer 714 includes two facing portions 714a that face the two ferromagnetic layers 712a via the underlayer 713, and a non-facing portion 714b that faces the MR element 50 and the insulating layer 32 via the underlayer 713 but does not face the two ferromagnetic layers 712a. The two facing portions 714a are connected to each other by the non-facing portion 714b.

[0136] The underlayer 713 includes two intermediate portions 713a interposed between the two ferromagnetic layers 712a and the two opposing portions 714a, and the cap layer 715 includes two protective portions 715a disposed on the two opposing portions 714a.

[0137] The underlayer 713 is formed of a metal material. In particular, in this embodiment, the underlayer 713 is formed of a ferromagnetic metal material. When the underlayer 713 is formed of a ferromagnetic metal material, the underlayer 713 may be formed of the same material as the ferromagnetic layer 712a. Note that at least the intervening portion 713a of the underlayer 713 may be magnetic. A portion of the underlayer 713 that is intervening between the MR element 50 and the insulating layer 32 and the antiferromagnetic layer 714 may or may not be magnetic.

[0138] The antiferromagnetic layer 714 may be made of, for example, the same material as the antiferromagnetic layer 73a in the first embodiment. The cap layer 715 may be made of, for example, the same material as the cap layer 74 in the first embodiment.

[0139] The buffer layer 711 and the ferromagnetic layer 712a constitute a first stacked structure 701. The underlayer 713, the antiferromagnetic layer 714, and the cap layer 715 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.

[0140] 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 intervening portion 713a, an opposing portion 714a, and a protective portion 715a.

[0141] In a stack consisting of a first stack 701 and a stack portion 702a disposed on the first stack 701, a facing portion 714a is exchange-coupled with a ferromagnetic layer 712a via an intervening portion 713a, thereby defining the direction of magnetization of the ferromagnetic layer 712a.

[0142] Each of the two magnetic field generators 700 further includes an antiferromagnetic portion made of an antiferromagnetic material. In this embodiment, the antiferromagnetic portion is substantially entirely formed by the facing portion 714a. Also, in this embodiment, the ferromagnetic portion 712 is substantially entirely formed by the ferromagnetic layer 712a. The facing portion 714a is exchange-coupled with the ferromagnetic layer 712a, thereby causing the antiferromagnetic portion to be exchange-coupled with the ferromagnetic portion 712. This determines the direction of magnetization of the ferromagnetic portion 712. The direction of magnetization of the ferromagnetic portion 712 coincides with the direction of magnetization of the ferromagnetic layer 712a. The ferromagnetic portion 712 and the antiferromagnetic portion generate a bias magnetic field based on the magnetization of the ferromagnetic portion 712. The bias magnetic field is applied to the MR element 50.

[0143] Since the ferromagnetic layer 712a is part of the first laminate 701 and the facing portion 714a is part of the laminate portion 702a, it can be said that the first laminate 701 and the laminate portion 702a constitute the magnetic field generator 700. The magnetic field generator 700 includes a buffer layer 711, a ferromagnetic layer 712a, an intervening portion 713a, a facing portion 714a, and a protective portion 715a.

[0144] The MR element 50 is disposed between two magnetic field generators 700. The two magnetic field generators 700 cooperate to apply a bias magnetic field to the MR element 50. The magnetization direction of the ferromagnetic layer 712 a of one of the two magnetic field generators 700 may be the same as the magnetization direction of the ferromagnetic layer 712 a of the other of the two magnetic field generators 700. In this case, the direction of the bias magnetic field generated by one of the two magnetic field generators 700 will be the same as the direction of the bias magnetic field generated by the other of the two magnetic field generators 700.

[0145] When the underlayer 713 is made of the same material as the ferromagnetic layer 712a, the ferromagnetic layer 712a and the intermediate portion 713a essentially form a single ferromagnetic layer. The facing portion 714a contacts the top surface of the single ferromagnetic layer and is exchange-coupled to the single ferromagnetic layer.

[0146] The maximum dimension of the ferromagnetic layer 712a in the stacking direction of the multiple magnetic films (direction parallel to the Z direction) is larger than the maximum dimension in the stacking direction of the underlayer 713. Also, the maximum dimension of the free layer 54 in the stacking direction is larger than the maximum dimension in the stacking direction of the underlayer 713.

[0147] The upper surface 50a of the MR element 50 faces the non-facing portion 714b of the antiferromagnetic layer 714. The distance between the non-facing portion 714b and the lower surface 50b of the MR element 50 is larger than the distance between the upper surface 50a and the lower surface 50b. The distance between the facing portion 714a of the antiferromagnetic layer 714 and the upper surface of the lower electrode 61 may be the same as the distance between the non-facing portion 714b and the lower surface 50b, or may be different from the distance between the non-facing portion 714b and the lower surface 50b. In the latter case, the maximum distance between the facing portion 714a and the upper surface of the lower electrode 61 may be larger than the distance between the non-facing portion 714b and the lower surface 50b.

[0148] The upper surface of the second stacked body 702, i.e., the upper surface of the cap layer 715, is in contact with the upper electrode 62. The planar shape of the second stacked body 702 (the shape viewed from the Z direction) may be the same as the planar shape of the upper electrode 62, or may be smaller than the planar shape of the upper electrode 62, or may be larger than the planar shape of the upper electrode 62.

[0149] Up to this point, the configuration of the magnetic field generator 700 has 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. 23 , 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. 23 , 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.

[0150] The two MR elements 50 are also electrically connected by the antiferromagnetic layer 714 of the second stack 702. The two MR elements 50 are also connected in series by the antiferromagnetic layer 714.

[0151] In addition, in this embodiment, since the magnetic sensor 1 has multiple MR elements 50 and multiple magnetic field generators 700, the magnetic sensor 1 has multiple underlayers 713, multiple antiferromagnetic layers 714, and multiple cap layers 715.

[0152] Next, a process for forming a plurality of magnetic field generators 700 according to this embodiment will be described. Here, focusing on one MR element 50, a process for forming two magnetic field generators 700 will be described. First, a photoresist mask is formed on the MR element 50 and the insulating layer 32. Next, the insulating layer 32 is etched. Next, while leaving the photoresist mask, the insulating layer 33, the buffer layer 711, and the initial ferromagnetic layer that will later become the ferromagnetic layer 712a are formed in this order. Next, the photoresist mask is removed. Next, the underlayer 713, the antiferromagnetic layer 714, and the cap layer 715 are formed in this order on the MR element 50, the ferromagnetic layer 712a, and the insulating layer 32. Next, a process for fixing the magnetization direction of the initial ferromagnetic layer is performed. The process for fixing the magnetization direction of the initial ferromagnetic layer is the same as the process for fixing the magnetization direction of the ferromagnetic part 72 according to the first embodiment. By fixing the direction of magnetization of the initial ferromagnetic layer, the initial ferromagnetic layer becomes the ferromagnetic layer 712a, and the magnetic field generator 700 is completed.

[0153] The ferromagnetic part 712 of the magnetic field generator 700 in this embodiment may include two ferromagnetic layers, as in the fourth and fifth modifications of the first embodiment. When the ferromagnetic part 712 includes two ferromagnetic layers, the magnetic field generator 700 may include a non-magnetic layer disposed between the two ferromagnetic layers, as in the fifth modification of the first embodiment.

[0154] Furthermore, the antiferromagnetic portion of the magnetic field generator 700 in this embodiment may include, in addition to the opposing portion 714a, an antiferromagnetic layer arranged between the buffer layer 711 and the ferromagnetic layer 712a, as in the third modified example of the first embodiment.

[0155] Other configurations, actions, and effects of this embodiment are the same as those of the first embodiment.

[0156] [Third embodiment] Next, a third embodiment of the present invention will be described with reference to Fig. 25 and Fig. 26. Fig. 25 is a plan view showing a main part of a magnetic sensor according to this embodiment. Fig. 26 is a cross-sectional view showing a part of a cross section taken along line 26-26 in Fig. 25.

[0157] Hereinafter, focusing on one MR element 50, differences in the configuration of the magnetic sensor 1 according to this embodiment from the first embodiment will be described. In this embodiment, each of the two magnetic field generators 70 is disposed closer to the MR element 50 than in the first embodiment. In particular, in this embodiment, each of the two magnetic field generators 70 is disposed so as to ride on the side surface 50c of the MR element 50. A portion of each of the two magnetic field generators 70 overlaps a portion of the MR element 50 when viewed from the Z direction. An insulating layer 33 is interposed between the MR element 50 and the two magnetic field generators 70.

[0158] FIG. 26 shows an example in which the configuration of each of the two magnetic field generators 70 is the same as that described with reference to FIG. 8 in the first embodiment. However, the configuration of each of the two magnetic field generators 70 may be the same as that of any of the multiple modified examples of the first embodiment. In particular, when the configuration of each of the two magnetic field generators 70 is the same as that of the fifth modified example of the first embodiment described with reference to FIG. 22 and the ferromagnetic layer 72a and the ferromagnetic layer 72b are antiferromagnetically exchange-coupled via the nonmagnetic layer 75, the following effect is achieved. The strength of the bias magnetic field based on the ferromagnetic layer 72a or 72b is greater than the strength of the bias magnetic field based on the entire ferromagnetic part 72. In this embodiment, the distance between the free layer 54 and the ferromagnetic layer 72a or 72b of the MR element 50 is smaller than that in the example shown in FIG. 22. Therefore, a bias magnetic field based on the ferromagnetic layer 72a or 72b can be applied to the free layer 54, the bias magnetic field having a strength greater than the strength of the bias magnetic field based on the entire ferromagnetic portion 72.

[0159] Next, a process for forming a plurality of magnetic field generators 70 in this embodiment will be described. Here, focusing on one MR element 50, a process for forming two magnetic field generators 70 will be described. First, a first photoresist mask is formed on the laminated film that will later become the MR element 50. Next, using the first photoresist mask, the laminated film is patterned by etching so that two side surfaces 50d (see FIG. 25) are formed on the laminated film. Next, with the first photoresist mask remaining, an insulating layer 32 is formed around the laminated film. Next, the first photoresist mask is removed.

[0160] Next, a second photoresist mask is formed on the laminated film and the insulating layer 32. Next, the laminated film is patterned by etching using the second photoresist mask so that two side surfaces 50c (see FIG. 25) are formed on the laminated film. This etching also etches the insulating layer 32. By forming the two side surfaces 50c on the laminated film, the laminated film becomes the MR element 50. Next, with the second photoresist mask remaining, an insulating layer 33 and two initial magnetic field generators 70P, which will later become the two magnetic field generators 70, are formed in this order. The configuration of the two initial magnetic field generators 70P is the same as in the first embodiment. Next, the second photoresist mask is removed.

[0161] Next, the magnetization direction of the initial ferromagnetic portions of each of the two initial magnetic field generators 70P is fixed. The method for fixing the magnetization direction of the initial ferromagnetic portions in this embodiment is basically the same as that in the first embodiment.

[0162] 27 to 30, a method for fixing the magnetization direction of the initial ferromagnetic portion in this embodiment will be described in detail below. First, as shown in FIG. 27, while applying a magnetic field component MF1 in one direction parallel to the first direction D1 (a bottom-to-top direction in FIG. 27) to the magnetic sensor 1, laser light is selectively irradiated onto the multiple initial magnetic field generators 70P corresponding to the resistance portions R1 and R2. After the laser light irradiation, the magnetization direction of each of the irradiated initial ferromagnetic portions of the multiple initial magnetic field generators 70P is fixed in the same direction as the magnetic field component MF1. As a result, as shown in FIG. 28, the multiple initial magnetic field generators 70P irradiated with the laser light become multiple magnetic field generators 70.

[0163] The laser light may be selectively applied to the multiple initial magnetic field generators 70P using, for example, a mask 103. The mask 103 has at least one opening 103a that exposes some or all of the multiple initial magnetic field generators 70P corresponding to the resistor portions R1 and R2. In this embodiment, particularly, some or all of the multiple MR elements 50 of the resistor portions R1 and R2 are also exposed from the at least one opening 103a. The multiple MR elements 50 of the resistor portions R3 and R4 and the multiple initial magnetic field generators 70P corresponding to the resistor portions R3 and R4 are covered by the mask 103. The laser light is applied to some or all of the multiple initial magnetic field generators 70P through the at least one opening 103a.

[0164] The laser light is also irradiated onto the multiple MR elements 50 of the resistor units R1 and R2. Therefore, during irradiation with the laser light, the temperatures of the multiple MR elements 50 of the resistor units R1 and R2 also rise. However, the magnetization direction of each of the magnetization fixed layers 52 of the multiple MR elements 50 of the resistor units R1 and R2 is maintained so as not to tilt due to the magnetic field component MF1. To maintain the magnetization direction of the magnetization fixed layer 52, a structure may be used in which the magnetization fixed layer 52 does not rise above the blocking temperature of the antiferromagnetic layer 521, or the blocking temperature of the antiferromagnetic layer 521 may be set higher than the blocking temperature of the antiferromagnetic unit 73. Alternatively, to maintain the magnetization direction of the magnetization fixed layer 52, the strength of the magnetic field component MF1 may be suppressed to a level that prevents the magnetization direction of the magnetization fixed layer 52 from tilting, or a structure may be used that increases the coercive force of the magnetization fixed layer 52 or makes it difficult for the magnetization direction of the magnetization fixed layer 52 to move.

[0165] 29 shows the next step. In this step, a laser beam is selectively applied to the initial magnetic field generators 70P corresponding to the resistors R3 and R4 while a magnetic field component MF2 is applied to the magnetic sensor 1 in another direction parallel to the first direction D1 (from top to bottom in FIG. 29). After the laser beam is applied, the magnetization direction of each of the initial ferromagnetic portions of the irradiated initial magnetic field generators 70P is fixed in the same direction as the magnetic field component MF2. As a result, the initial magnetic field generators 70P irradiated with the laser beam become a plurality of magnetic field generators 70, as shown in FIG. 30.

[0166] Similar to the process shown in FIG. 27 , the laser light may be selectively applied to the multiple initial magnetic field generators 70P using, for example, a mask 104. The mask 104 has at least one opening 104a that exposes some or all of the multiple initial magnetic field generators 70P corresponding to the resistor portions R3 and R4. In this embodiment, particularly, some or all of the multiple MR elements 50 of the resistor portions R3 and R4 are also exposed through the at least one opening 104a. The multiple MR elements 50 of the resistor portions R1 and R2 and the multiple magnetic field generators 70 corresponding to the resistor portions R1 and R2 are covered by the mask 104. The laser light is applied to some or all of the multiple initial magnetic field generators 70P through the at least one opening 104a.

[0167] The laser light is also irradiated onto the MR elements 50 of the resistor units R3 and R4. Therefore, the temperatures of the MR elements 50 of the resistor units R3 and R4 also rise during irradiation with the laser light. However, the magnetization direction of the magnetization fixed layer 52 of each of the MR elements 50 of the resistor units R3 and R4 is maintained not to be tilted by the magnetic field component MF2, similar to the magnetization direction of the magnetization fixed layer 52 of each of the MR elements 50 of the resistor units R1 and R2.

[0168] Other configurations, actions, and effects of this embodiment are the same as those of the first embodiment.

[0169] [Variations] Next, a modified example of the magnetic sensor 1 according to the present embodiment will be described with reference to FIG. 31. FIG. 31 is a cross-sectional view showing a main part of the modified example of the magnetic sensor 1 according to the present embodiment. In this modified example, the magnetization fixed layer 52 of the MR element 50 includes an antiferromagnetic layer 521 disposed on the buffer layer 51, a ferromagnetic layer 523 disposed on the antiferromagnetic layer 521, a nonmagnetic layer 524 disposed on the ferromagnetic layer 523, and a ferromagnetic layer 525 disposed on the nonmagnetic layer 524. The ferromagnetic layers 523 and 525 are formed of a ferromagnetic material containing one or more elements selected from the group consisting of Co, Fe, and Ni. The nonmagnetic layer 524 is formed of a nonmagnetic metal material such as Ru.

[0170] The antiferromagnetic layer 521 may be formed of, for example, the same material as the antiferromagnetic layer 521 in the first embodiment shown in Fig. 18. As in the first embodiment, the antiferromagnetic layer 73a of the antiferromagnetic part 73 of the magnetic field generator 70 and the antiferromagnetic layer 521 may contain the same element.

[0171] The antiferromagnetic layer 521 generates exchange coupling with the ferromagnetic layer 523, pinning the direction of magnetization of the ferromagnetic layer 523. The ferromagnetic layer 523 and the ferromagnetic layer 525 are antiferromagnetically exchange coupled via the nonmagnetic layer 524. The magnetization directions of the ferromagnetic layer 523 and the ferromagnetic layer 525 are opposite to each other. The magnetization direction of the magnetization pinned layer 52 is the same as the magnetization direction of the ferromagnetic layer 525.

[0172] In the modified example, the magnetization direction of the ferromagnetic layer 523 and the magnetization direction of the ferromagnetic layer 525 are opposite to each other, so the net moment of the magnetization fixed layer 52 is small. Therefore, the Zeeman energy, which is the energy generated when an external magnetic field acts on the magnetic moment, is small in the magnetization fixed layer 52. As a result, even if the temperature of the multiple MR elements 50 rises due to the laser light used to irradiate the initial magnetic field generator 70P, as in the present embodiment, the magnetization direction of the magnetization fixed layer 52 is less likely to tilt toward the direction of the magnetic field component MF1 or the direction of the magnetic field component MF2 than when the Zeeman energy is large.

[0173] In the modified example, the magnetization amount Mst1 per unit area of the ferromagnetic layer 523 is different from the magnetization amount Mst2 per unit area of the ferromagnetic layer 525. In the modified example, it is particularly preferable to set the magnetization amount Mst1 equal to or less than the magnetization amount Mst2. If Mst1>Mst2, when the temperature of the multiple MR elements 50 increases due to the laser light irradiated onto the initial magnetic field generator 70P, the direction of the magnetization of the ferromagnetic layer 523 may tilt toward the direction of the magnetic field component MF1 or the direction of the magnetic field component MF2, regardless of the magnitude of the intensity of the magnetic field component MF1 or the magnetic field component MF2.

[0174] On the other hand, when Mst1≦Mst2, if the temperature of the multiple MR elements 50 rises due to the laser light irradiating the initial magnetic field generator 70P, the magnetization direction of the ferromagnetic layer 523 tilts toward the direction opposite to the direction of magnetic field component MF1 or the direction of magnetic field component MF2 when the intensity of magnetic field component MF1 or magnetic field component MF2 is small. Furthermore, in this case, when the intensity of magnetic field component MF1 or magnetic field component MF2 is large, the magnetization direction of the ferromagnetic layer 523 tilts toward the direction of magnetic field component MF1 or the direction of magnetic field component MF2. Therefore, when Mst1≦Mst2, by adjusting the intensity of magnetic field components MF1 and MF2 to appropriate levels, it is possible to hardly change the magnetization direction of the ferromagnetic layer 523. This makes it possible to suppress changes in the magnetization direction of the magnetization fixed layer 52.

[0175] Even when Mst1>Mst2, if the coercive force of the ferromagnetic layer 523 is large, the magnetization direction of the magnetization fixed layer 52 is less likely to tilt toward the direction of the magnetic field component MF1 or the direction of the magnetic field component MF2. Also, even when Mst1>Mst2, depending on the magnetostriction of the ferromagnetic layer 523 and the state of stress around the MR element 50, the magnetization direction of the magnetization fixed layer 52 is less likely to tilt toward the direction of the magnetic field component MF1 or the direction of the magnetic field component MF2.

[0176] [Fourth embodiment] Next, a fourth embodiment of the present invention will be described with reference to Fig. 32 and Fig. 33. Fig. 32 is a plan view showing a main part of a magnetic sensor according to this embodiment. Fig. 33 is a cross-sectional view showing a part of a cross section taken along line 33-33 in Fig. 32.

[0177] Hereinafter, focusing on one MR element 50, differences in the configuration of the magnetic sensor 1 according to this embodiment from the second embodiment will be described. In this embodiment, each of the two magnetic field generators 700 is disposed closer to the MR element 50 than in the second embodiment. In particular, in this embodiment, the ferromagnetic layer 712a of the ferromagnetic portion 712 of each of the two magnetic field generators 700 is disposed so as to extend over the side surface 50c of the MR element 50. A portion of the ferromagnetic layer 712a overlaps a portion of the MR element 50 when viewed from the Z direction. An insulating layer 33 is interposed between the MR element 50 and the two magnetic field generators 700.

[0178] Next, a process for forming a plurality of magnetic field generators 700 in this embodiment will be described. Here, focusing on one MR element 50, a process for forming two magnetic field generators 700 will be described. First, a photoresist mask is formed on the laminated film, which will later become the MR element 50 and has two side surfaces 50d (see FIG. 32), and on the insulating layer 32. Next, the laminated film is patterned by etching using the photoresist mask so that two side surfaces 50c (see FIG. 32) are formed in the laminated film. In this etching, the insulating layer 32 is also etched. By forming the two side surfaces 50c in the laminated film, the laminated film becomes the MR element 50.

[0179] Next, with the photoresist mask remaining, an insulating layer 33, a buffer layer 711, and an initial ferromagnetic layer that will later become the ferromagnetic layer 712a are formed in this order. The photoresist mask is then removed. Next, an underlayer 713, an antiferromagnetic layer 714, and a cap layer 715 are formed in this order on the MR element 50, the initial ferromagnetic layer, and the insulating layer 32. Next, a step of fixing the magnetization direction of the initial ferromagnetic layer is performed. The step of fixing the magnetization direction of the initial ferromagnetic layer is the same as in the second embodiment. By fixing the magnetization direction of the initial ferromagnetic layer, the initial ferromagnetic layer becomes the ferromagnetic layer 712a, and the magnetic field generator 700 is completed.

[0180] Other configurations, actions, and effects of this embodiment are the same as those of the second embodiment.

[0181] [Variations] Next, first to third 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. 34. Fig. 34 is a plan view showing a main part of the first modified example of the magnetic sensor 1.

[0182] In the first modification, 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. This connects the plurality of MR elements 50 lined up in a row in the first direction D1 in series. In the first modification, the plurality of connecting electrodes electrically connects 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.

[0183] 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 an antiferromagnetic layer 714 (see FIG. 33) of the second stacked body 702. The two MR elements 50 are also connected in series by the antiferromagnetic layer 714.

[0184] Next, a second modified example will be described with reference to FIG. 35. FIG. 35 is a cross-sectional view showing a main part of the second modified example of the magnetic sensor 1. In the second modified example, the first laminate 701 includes a ferromagnetic part 721A made of a ferromagnetic material instead of the ferromagnetic layer 712a. The ferromagnetic part 721A has the same function as the ferromagnetic part 712. The shape and arrangement of the ferromagnetic part 721A may be the same as the shape and arrangement of the ferromagnetic layer 712a.

[0185] The second laminate 702 includes an underlying portion 721B instead of the underlying layer 713. The shape and arrangement of the underlying portion 721B may be the same as those of the underlying layer 713. The underlying portion 721B also includes an intermediate portion 721Ba interposed between the ferromagnetic portion 721A and the facing portion 714a, and a non-interposed portion 721Bb other than the intermediate portion 721Ba. The laminate portion 702a includes the intermediate portion 721Ba instead of the intermediate portion 713a.

[0186] In particular, in the second modified example, the ferromagnetic portion 721A and the underlying portion 721B are configured by one ferromagnetic layer 721. In Fig. 35, the boundary between the ferromagnetic portion 721A and the underlying portion 721B is indicated by a dashed line.

[0187] Next, a third modified example will be described with reference to Fig. 36. Fig. 36 is a cross-sectional view showing a main part of the third modified example of the magnetic sensor 1. In the third modified example, the underlayer 713 is not provided, and an antiferromagnetic layer 714 is disposed on the MR element 50, the two ferromagnetic layers 712a, and the insulating layer 32.

[0188] [Fifth embodiment] Next, a fifth 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. 37. Fig. 37 is a perspective view showing a magnetic sensor system 200 according to this embodiment.

[0189] 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.

[0190] 37, 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.

[0191] Next, a schematic configuration of the magnetic sensor 201 according to this embodiment will be described with reference to Fig. 38. Fig. 38 is a circuit diagram showing the circuit configuration of the magnetic sensor 201.

[0192] 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.

[0193] Each of the resistor units R31 to R34 includes a plurality of MR elements 50. The plurality of MR elements 50 constituting the resistor unit R31 are provided between the power supply port V3 and the output port E31 in terms of the circuit configuration. The plurality of MR elements 50 constituting the resistor unit R32 are provided between the output port E31 and the ground port G3 in terms of the circuit configuration. The plurality of MR elements 50 constituting the resistor unit R33 are provided between the output port E32 and the ground port G3 in terms of the circuit configuration. The plurality of MR elements 50 constituting the resistor unit R34 are provided between the power supply port V3 and the output port E32 in terms of the circuit configuration.

[0194] The configuration of the multiple MR elements 50 is the same as that of the third embodiment. That is, each of the multiple 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 FIG. 26 in the third embodiment.

[0195] 38, 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. 38, 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.

[0196] The magnetic sensor 201 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 third 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. 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.

[0197] 38, 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.

[0198] The direction of the bias magnetic field essentially indicates the direction of magnetization of the ferromagnetic portions 72 of the plurality of magnetic field generators 70. The magnetization direction of the ferromagnetic portions 72 of the plurality of magnetic field generators 70 corresponding to the resistor portions R31 and R34 is the Y direction. The magnetization direction of the ferromagnetic portions 72 of the plurality of magnetic field generators 70 corresponding to the resistor portions R32 and R33 is the -Y direction.

[0199] 38, multiple open arrows drawn to overlap the resistor units R31 to R34 respectively represent the magnetization direction 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.

[0200] Next, the configuration of magnetic sensor 201 will be specifically described with reference to Fig. 39 to Fig. 41. Fig. 39 is a perspective view showing a part of magnetic sensor 201. Fig. 40 is a plan view showing a part of magnetic sensor 201. Fig. 41 is a side view showing a part of magnetic sensor 201.

[0201] 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.

[0202] 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.

[0203] As shown in FIGS. 39 to 41 , 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.

[0204] 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.

[0205] 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 39 to 41, 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.

[0206] As shown in FIGS. 39 and 40 , 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.

[0207] 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.

[0208] 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 configured with 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 42 to 44, which will be described later.

[0209] 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.

[0210] 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.

[0211] 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.

[0212] 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.

[0213] 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.

[0214] 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.

[0215] 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.

[0216] 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. 37).

[0217] Next, the multiple yokes 90C and the multiple yokes 90D will be described in detail with reference to Figures 42 to 44. Figure 42 is a plan view showing a main portion of magnetic sensor 201. Figure 43 is a cross-sectional view showing a part of a cross section indicated by line 43-43 in Figure 42. Figure 44 is a cross-sectional view showing a part of a cross section indicated by line 44-44 in Figure 42.

[0218] Hereinafter, any one of the plurality of yokes 90C and the plurality of yokes 90D will be denoted by the reference symbol 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 third embodiment.

[0219] The configuration of the yoke 90 will be described below, focusing on one MR element 50. Two yokes 90 are disposed on both sides of the MR element 50 in a direction parallel to the X direction. The two yokes 90 are embedded in an insulating layer 32. An insulating layer 32 is interposed between the MR element 50 and the two yokes 90 and between the lower electrode 61 and the two yokes 90. Each of the two yokes 90 may include, in addition to a magnetic layer, a buffer layer interposed between the magnetic layer and the insulating layer 32 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.

[0220] The two yokes 90 are arranged between two magnetic field generators 70 that are arranged at a predetermined distance in a direction parallel to the Y direction. The ferromagnetic layer 72a of the magnetic field generator 70 is arranged so as to overlap the two yokes 90 when viewed from the Y direction or the -Y direction.

[0221] The ferromagnetic layer 72a is disposed so as to ride on the yoke 90. When viewed from the Z direction, a portion of the ferromagnetic layer 72a overlaps a portion of the yoke 90. An insulating layer 33 is interposed between the ferromagnetic layer 72a and the yoke 90. A portion of the buffer layer 71 of the magnetic field generator 70 is interposed between the ferromagnetic layer 72a and the insulating layer 33.

[0222] In this embodiment, the upper electrode 62 is disposed on the MR element 50 , the two magnetic field generators 70 , the two yokes 90 and the insulating layer 32 .

[0223] The configuration of the magnetic field generator 70 in this embodiment is not limited to the examples shown in Figures 39, 40, 42 and 44. The magnetic sensor 201 according to this embodiment may include a plurality of magnetic field generators having the same configuration as any one of the first, second, third or fourth embodiments, instead of the plurality of magnetic field generators 70 in this embodiment. The other configurations, actions and effects of this embodiment are the same as any one of the first to fourth embodiments.

[0224] 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 fifth 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.

[0225] 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.

[0226] Furthermore, the modified example of the magnetic sensor 1 according to the third embodiment is not limited to the third embodiment, and may be applied to embodiments other than the third embodiment.

[0227] Furthermore, when a first magnetic field generator including ferromagnetic parts having magnetization in a first direction and a second magnetic field generator including ferromagnetic parts having magnetization in a second direction different from the first direction are formed in this order, when irradiating the first initial magnetic field generator, which will later become the first magnetic field generator, with laser light, the second initial magnetic field generator, which will later become the second magnetic field generator, may also be irradiated with laser light. In this case, after fixing the magnetization direction of the ferromagnetic parts of the first magnetic field generator, only the second initial magnetic field generator is irradiated with laser light to fix the magnetization direction of the ferromagnetic parts of the second magnetic field generator.

[0228] As described above, the magnetic sensor manufactured by the manufacturing method of the present invention comprises at least one magnetoresistive element including a magnetization fixed layer having magnetization including a component in a first direction and a magnetization whose direction is fixed, and a free layer having magnetization whose direction is variable in response to a target magnetic field that is a magnetic field to be detected, and at least one magnetic field generator including a ferromagnetic part made of a ferromagnetic material and having magnetization including a component in a second direction different from the first direction and having a magnetization whose direction is fixed, and an antiferromagnetic part made of an antiferromagnetic material and exchange-coupled with the ferromagnetic part, and configured to generate a magnetic field to be applied to the at least one magnetoresistive element. The manufacturing method of the magnetic sensor of the present invention includes the steps of forming at least one magnetoresistive element and forming at least one magnetic field generator. The step of forming at least one magnetic field generator includes the steps of: forming at least one initial magnetic field generator including an initial ferromagnetic portion and an antiferromagnetic portion, which will later become the ferromagnetic portion; and fixing the direction of magnetization of the initial ferromagnetic portion using a laser beam and a first external magnetic field including a component in a first magnetic field direction, so that the initial ferromagnetic portion becomes the ferromagnetic portion. The first magnetic field direction may be identical to the second direction.

[0229] In the method for manufacturing a magnetic sensor of the present invention, the step of forming at least one magnetoresistive effect element may include the steps of forming at least one initial magnetoresistive effect element including an initial magnetization pinned layer and a free layer that will later become a magnetization pinned layer, and pinning the direction of magnetization of the initial magnetization pinned layer using laser light and a second external magnetic field including a component of a second magnetic field direction so that the initial magnetization pinned layer becomes a magnetization pinned layer. The second magnetic field direction may be identical to the first direction. The step of pinning the direction of magnetization of the initial magnetization pinned layer may be performed before the step of pinning the direction of magnetization of the initial ferromagnetic portion.

[0230] In the method for manufacturing a magnetic sensor of the present invention, the magnetization fixed layer may include a first ferromagnetic layer made of a ferromagnetic material, a second ferromagnetic layer made of a ferromagnetic material, a nonmagnetic layer made of a nonmagnetic metal material and interposed between the first ferromagnetic layer and the second ferromagnetic layer, and an antiferromagnetic layer made of an antiferromagnetic material and in contact with the first ferromagnetic layer. The amount of magnetization per unit area of the first ferromagnetic layer may be equal to or less than the amount of magnetization per unit area of the second ferromagnetic layer.

[0231] In the method for manufacturing a magnetic sensor of the present invention, the magnetization fixed layer may include a ferromagnetic layer made of a ferromagnetic material and an antiferromagnetic layer made of an antiferromagnetic material and in contact with the ferromagnetic layer, and the antiferromagnetic portion and the antiferromagnetic layer may contain at least one of the same elements.

[0232] In the method for manufacturing a magnetic sensor of the present invention, in the step of fixing the magnetization direction of the initial ferromagnetic portion, the laser light may not be irradiated onto at least one magnetoresistive element, or may be irradiated onto at least one magnetoresistive element.

[0233] Furthermore, the method for manufacturing a magnetic sensor of the present invention may further include, after the step of fixing the direction of magnetization of the initial ferromagnetic portion, a step of performing an annealing treatment in which the laminate including at least one magnetoresistance effect element and at least one magnetic field generator is heated at a predetermined temperature.

[0234] In the method for manufacturing a magnetic sensor of the present invention, the at least one magnetoresistive element may be a first magnetoresistive element and a second magnetoresistive element. The at least one magnetic field generator may be a first magnetic field generator configured to generate a magnetic field applied to the first magnetoresistive element and a second magnetic field generator configured to generate a magnetic field applied to the second magnetoresistive element. Between the pair of the first magnetoresistive element and the first magnetic field generator and the pair of the second magnetoresistive element and the second magnetic field generator, there may not be any other pair of magnetoresistive element and magnetic field generator capable of detecting the magnetoresistive effect. The magnetization direction of the ferromagnetic portion of the first magnetic field generator and the magnetization direction of the ferromagnetic portion of the second magnetic field generator may be different from each other. The step of forming at least one magnetic field generator may be a step of forming a first magnetic field generator and a second magnetic field generator. The step of forming at least one initial magnetic field generator may be a step of forming a first initial magnetic field generator including a first initial ferromagnetic portion and an antiferromagnetic portion of the first magnetic field generator, which will later become the ferromagnetic portion of the first magnetic field generator, and a second initial magnetic field generator including a second initial ferromagnetic portion and an antiferromagnetic portion of the second magnetic field generator, which will later become the ferromagnetic portion of the second magnetic field generator. The step of fixing the magnetization direction of the initial ferromagnetic portion may be a step of irradiating the first initial magnetic field generator and the second initial magnetic field generator with laser light in this order to fix the magnetization direction of the first initial ferromagnetic portion and the magnetization direction of the second initial ferromagnetic portion. When the second initial magnetic field generator is irradiated with laser light, the temperature of the ferromagnetic portion of the first initial magnetic field generator may not rise above the blocking temperature.

[0235] In the method for manufacturing a magnetic sensor of the present invention, the at least one magnetoresistive element may be a first magnetoresistive element and a second magnetoresistive element. The at least one magnetic field generator may be a first magnetic field generator configured to generate a magnetic field to be applied to the first magnetoresistive element and a second magnetic field generator configured to generate a magnetic field to be applied to the second magnetoresistive element. The magnetization direction of the ferromagnetic portion of the first magnetic field generator and the magnetization direction of the ferromagnetic portion of the second magnetic field generator may be the same. The step of forming at least one magnetic field generator may be a step of forming a first magnetic field generator and a second magnetic field generator. The step of forming at least one initial magnetic field generator may be a step of forming a first initial magnetic field generator including a first initial ferromagnetic portion that will later become the ferromagnetic portion of the first magnetic field generator and an antiferromagnetic portion of the first magnetic field generator, and a second initial magnetic field generator including a second initial ferromagnetic portion that will later become the ferromagnetic portion of the second magnetic field generator and an antiferromagnetic portion of the second magnetic field generator. The step of fixing the magnetization direction of the initial ferromagnetic portion may be a step of simultaneously irradiating the first initial magnetic field generator and the second initial magnetic field generator with laser light to fix the magnetization direction of the first initial ferromagnetic portion and the magnetization direction of the second initial ferromagnetic portion.

[0236] Furthermore, in the method for manufacturing a magnetic sensor of the present invention, the at least one magnetoresistive effect element may be a plurality of magnetoresistive effect elements. The at least one magnetic field generator may be a plurality of magnetic field generators. The step of forming at least one magnetic field generator may be a step of forming a plurality of magnetic field generators. The step of forming at least one initial magnetic field generator may be a step of forming a plurality of initial magnetic field generators, each including an initial ferromagnetic portion and an antiferromagnetic portion that will later become a ferromagnetic portion. The step of fixing the magnetization direction of the initial ferromagnetic portion may be a step of sequentially irradiating one or more of the plurality of initial magnetic field generators with laser light to fix the magnetization direction of each initial ferromagnetic portion of the plurality of initial magnetic field generators. [Explanation of symbols]

[0237] 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 portion, 72a...ferromagnetic layer, 73...antiferromagnetic portion, 73a...antiferromagnetic layer, 74...cap layer, 100...magnetic sensor device, 101, 102...mask, D1...first direction, D2...second direction, E11, E12, E21, E22...output port, G1, G2...ground port, R1 to R4, R11 to R14, R21 to R24...resistance portion, V1, V2...power supply port.

Claims

1. At least one magnetoresistive element including a magnetization fixed layer having magnetization including a component in a first direction and a magnetization whose direction is fixed, and a free layer having magnetization whose direction can be changed according to a target magnetic field that is a magnetic field to be detected; A method for manufacturing a magnetic sensor comprising: a ferromagnetic portion made of a ferromagnetic material and having a magnetization whose direction is fixed and which includes a component in a second direction different from the first direction; and an antiferromagnetic portion made of an antiferromagnetic material and exchange-coupled with the ferromagnetic portion, the magnetic sensor including at least one magnetic field generator configured to generate a magnetic field to be applied to the at least one magnetoresistance effect element, the method comprising: The manufacturing method includes: forming the at least one magnetoresistive element; forming the at least one magnetic field generator; the step of forming the at least one magnetic field generator includes a step of forming at least one initial magnetic field generator including an initial ferromagnetic portion that will later become the ferromagnetic portion and the antiferromagnetic portion; and a step of fixing the direction of magnetization of the initial ferromagnetic portion so that the initial ferromagnetic portion becomes the ferromagnetic portion using laser light and a first external magnetic field including a component in a first magnetic field direction.

2. The step of forming the at least one magnetoresistive effect element includes a step of forming at least one initial magnetoresistive effect element including an initial magnetization fixed layer that will later become the magnetization fixed layer and the free layer; 2. A method for manufacturing a magnetic sensor according to claim 1, further comprising a step of fixing the direction of magnetization of the initial magnetization fixed layer using laser light and a second external magnetic field including a component in a second magnetic field direction so that the initial magnetization fixed layer becomes the magnetization fixed layer.

3. 3. The method for manufacturing a magnetic sensor according to claim 2, wherein the step of fixing the direction of magnetization of the initial magnetization fixed layer is performed before the step of fixing the direction of magnetization of the initial ferromagnetic portion.

4. 2. A method for manufacturing a magnetic sensor as described in claim 1, wherein the magnetization fixed layer includes a first ferromagnetic layer made of a ferromagnetic material, a second ferromagnetic layer made of a ferromagnetic material, a non-magnetic layer made of a non-magnetic metal material and interposed between the first ferromagnetic layer and the second ferromagnetic layer, and an antiferromagnetic layer made of an antiferromagnetic material and in contact with the first ferromagnetic layer.

5. 5. The method for manufacturing a magnetic sensor according to claim 4, wherein the magnetization amount per unit area of the first ferromagnetic layer is equal to or less than the magnetization amount per unit area of the second ferromagnetic layer.

6. the fixed magnetization layer includes a ferromagnetic layer made of a ferromagnetic material and an antiferromagnetic layer made of an antiferromagnetic material and in contact with the ferromagnetic layer; 2. The method for manufacturing a magnetic sensor according to claim 1, wherein the antiferromagnetic portion and the antiferromagnetic layer contain at least one same element.

7. 2. The method for manufacturing a magnetic sensor according to claim 1, wherein in the step of fixing the direction of magnetization of the initial ferromagnetic portion, the laser light is not irradiated onto the at least one magnetoresistive element.

8. 2. The method for manufacturing a magnetic sensor according to claim 1, wherein in the step of fixing the direction of magnetization of the initial ferromagnetic portion, the laser light is irradiated onto the at least one magnetoresistive element.

9. 2. The method for manufacturing a magnetic sensor according to claim 1, further comprising a step of performing an annealing process on the laminate including the at least one magnetoresistive element and the at least one magnetic field generator by heating the laminate at a predetermined temperature after the step of fixing the magnetization direction of the initial ferromagnetic portion.

10. the at least one magnetoresistive element is a first magnetoresistive element and a second magnetoresistive element; the at least one magnetic field generator is a first magnetic field generator configured to generate a magnetic field to be applied to the first magnetoresistive element, and a second magnetic field generator configured to generate a magnetic field to be applied to the second magnetoresistive element; between the set of the first magnetoresistive element and the first magnetic field generator and the set of the second magnetoresistive element and the second magnetic field generator, there is no other set of a magnetoresistive element and another magnetic field generator capable of detecting a magnetoresistive effect, 2. The method for manufacturing a magnetic sensor according to claim 1, wherein the direction of magnetization of the ferromagnetic portion of the first magnetic field generator and the direction of magnetization of the ferromagnetic portion of the second magnetic field generator are different from each other.

11. the step of forming at least one magnetic field generator is a step of forming the first magnetic field generator and the second magnetic field generator; the step of forming the at least one initial magnetic field generator is a step of forming a first initial magnetic field generator including a first initial ferromagnetic portion that will later become the ferromagnetic portion of the first magnetic field generator and the antiferromagnetic portion of the first magnetic field generator, and a second initial magnetic field generator that will later become the ferromagnetic portion of the second magnetic field generator and the antiferromagnetic portion of the second magnetic field generator, the step of fixing the magnetization direction of the initial ferromagnetic portion is a step of irradiating the first initial magnetic field generator and the second initial magnetic field generator with the laser light in this order, thereby fixing the magnetization direction of the first initial ferromagnetic portion and the magnetization direction of the second initial ferromagnetic portion; 11. The method for manufacturing a magnetic sensor according to claim 10, wherein the temperature of the ferromagnetic portion of the first initial magnetic field generator does not rise above a blocking temperature when the laser light is irradiated onto the second initial magnetic field generator.

12. the at least one magnetoresistive element is a first magnetoresistive element and a second magnetoresistive element, the at least one magnetic field generator is a first magnetic field generator configured to generate a magnetic field to be applied to the first magnetoresistive element, and a second magnetic field generator configured to generate a magnetic field to be applied to the second magnetoresistive element; the direction of magnetization of the ferromagnetic portion of the first magnetic field generator and the direction of magnetization of the ferromagnetic portion of the second magnetic field generator are the same; the step of forming at least one magnetic field generator is a step of forming the first magnetic field generator and the second magnetic field generator; the step of forming the at least one initial magnetic field generator is a step of forming a first initial magnetic field generator including a first initial ferromagnetic portion that will later become the ferromagnetic portion of the first magnetic field generator and the antiferromagnetic portion of the first magnetic field generator, and a second initial magnetic field generator that will later become the ferromagnetic portion of the second magnetic field generator and the antiferromagnetic portion of the second magnetic field generator, 2. The method for manufacturing a magnetic sensor according to claim 1, wherein the step of fixing the direction of magnetization of the initial ferromagnetic portion comprises simultaneously irradiating the first initial magnetic field generator and the second initial magnetic field generator with the laser light to fix the direction of magnetization of the first initial ferromagnetic portion and the direction of magnetization of the second initial ferromagnetic portion.

13. the at least one magnetoresistive element is a plurality of magnetoresistive elements, the at least one magnetic field generator is a plurality of magnetic field generators; the step of forming the at least one magnetic field generator is a step of forming the plurality of magnetic field generators; the step of forming the at least one initial magnetic field generator is a step of forming a plurality of initial magnetic field generators, each including the initial ferromagnetic portion and the antiferromagnetic portion, which will later become the ferromagnetic portion; 2. The method for manufacturing a magnetic sensor according to claim 1, wherein the step of fixing the direction of magnetization of the initial ferromagnetic portion comprises sequentially irradiating the laser light onto one or more of the plurality of initial magnetic field generators to fix the direction of magnetization of the initial ferromagnetic portion of each of the plurality of initial magnetic field generators.

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