JP2019174438A - Magnetic detection device - Google Patents

Abstract

To provide a magnetic detection device capable of having higher accuracy.SOLUTION: A magnetic detection device 1 includes a first magnetic sensor unit 1000a, a second magnetic sensor unit 1000b, a third magnetic sensor unit 1000c, and a fourth magnetic sensor unit 1000d. The first and the second magnetic sensor units are arranged in a first direction so that a magnetic sensitive axis direction is the first direction, the third and the fourth magnetic sensor units are arranged in a second direction so that a magnetic sensitive axis direction is the second direction, the first and the second magnetic sensor units are arranged between planes which include each centroid of the third and the fourth magnetic sensor units and whose normal is in the second direction, and the third and the fourth magnetic sensor units are arranged between planes which include each centroid of the first and the second magnetic sensor units and whose normal is in the first direction.SELECTED DRAWING: Figure 7

Description

  The present disclosure relates to a magnetic detection device.

  For example, as a device for measuring a magnetic field of a living body such as a heart or a brain, there is a biomagnetic measuring device using a SQUID (Superconducting Quantum Interference Device) sensor. By arranging a large number of SQUID sensors and using them for measurement of biomagnetism, two-dimensional magnetic information such as a magnetocardiogram or a magnetoencephalogram can be obtained (for example, Patent Document 1).

  In recent years, a magnetic sensor that can detect a weak magnetic field of about several tens of pT such as a biomagnetic field and operates at room temperature has been studied. An example of a magnetic sensor that can detect a minute magnetic field is an MR sensor.

  Among MR sensors, a spin valve MR magnetic sensor has a structure (ferromagnetic material / nonmagnetic / ferromagnetic material) in which a nonmagnetic material is sandwiched between ferromagnetic materials. In the spin valve MR magnetic sensor, the magnetization of one ferromagnetic material is fixed by an antiferromagnetic material to form a magnetization fixed layer. In general, a spin-valve MR magnetic sensor has a structure (spin valve structure) that can freely rotate the magnetization of another ferromagnetic material with respect to an external magnetic field as a magnetization free layer. In the spin valve MR magnetic sensor, when an input magnetic field is applied from the outside and the relative angle between the magnetization of the magnetization fixed layer and the magnetization of the magnetization free layer changes, the current flowing through the non-magnetic intermediate layer changes. Can be detected (for example, Patent Document 2).

  A spin-valve MR magnetic sensor is known to exhibit a large magnetoresistance (MR) change with a minute magnetic field, and is mainly used for a magnetic head of a hard disk or the like. In addition, it is known that a spin valve MR magnetic sensor has higher sensitivity than a magnetic sensor (Hall element) using the Hall effect, that is, can detect a minute magnetic field (for example, Patent Documents). 3 and Patent Document 4).

  As a magnetic detection method, a closed loop method is generally known, and is mainly used for a cored current sensor (for example, Patent Document 5). In the closed loop method, a feedback current corresponding to a change in voltage of the magnetic sensor generated when an input magnetic field is applied from the outside flows through the coil, and a cancel magnetic field in the opposite direction with the same strength as the input magnetic field is applied to the MR sensor. Therefore, ideally, the magnetic field applied to the MR sensor is always constant. Since the feedback current value at this time is proportional to the input magnetic field, the value of the input magnetic field can be calculated by reading the feedback current value.

  By combining the MR sensor, a coil for generating a canceling magnetic field, and an electric circuit for generating a feedback current, the MR sensor can be operated in a closed-loop manner. When the MR sensor is operated in a closed loop, the measurable magnetic field range can be made dependent on the coil shape, so that the measurement magnetic field range can be easily designed. By operating the MR sensor in a closed loop, a small micro magnetic sensor that operates at room temperature can be manufactured. If these are arranged in an array, one sensor is small, so that the magnetic field can be detected with high spatial resolution and magnetic field resolution. Therefore, as an application, for example, it is suitable for detection of biomagnetic fields such as cardiac magnetic field and brain magnetic field, and detection of scratches and corrosion of metal materials.

JP-A-5-232202 JP 9-199769 A Japanese Patent Laid-Open No. 2005-221383 JP2013-105825A Japanese Patent Laid-Open No. 2014-235045

  However, further improvement in accuracy is required as a magnetic detection device. An object of the present disclosure is to provide a magnetic detection device capable of further increasing accuracy.

  A magnetic detection device according to an embodiment of the present disclosure includes a magnetic sensor unit including a substrate and an element unit, a cancel magnetic field generation unit, and an electric circuit, and at least a part of the magnetic sensor unit includes the cancel magnetic field. A plurality of magnetic sensor units existing inside the envelope surface of the generator are provided. The element unit outputs a detection value corresponding to the input magnetic field component in the direction of the magnetosensitive axis. The canceling magnetic field generating unit is formed by winding a conductor with a winding axis as a winding axis in a direction substantially parallel to the magnetosensitive axis. The electrical circuit applies a feedback current based on the detected value to the cancel magnetic field generation unit, thereby generating a cancel magnetic field that reduces the input magnetic field in the cancel magnetic field generation unit. The plurality of magnetic sensor units include at least a first magnetic sensor unit, a second magnetic sensor unit, a third magnetic sensor unit, and a fourth magnetic sensor unit. The first magnetic sensor unit and the second magnetic sensor unit are arranged side by side in the first direction so that the direction of the magnetosensitive axis is the first direction. The third magnetic sensor unit and the fourth magnetic sensor unit are aligned in the second direction so that the direction of the magnetosensitive axis is a second direction substantially orthogonal to the first direction. Be placed. The first magnetic sensor unit and the second magnetic sensor unit include a plane that includes the center of gravity of the third magnetic sensor unit and has the second direction as a normal direction, and the fourth magnetic sensor unit. And a plane having a normal direction in the second direction. The third magnetic sensor unit and the fourth magnetic sensor unit include a plane that includes the center of gravity of the first magnetic sensor unit and that has the first direction as a normal direction, and the second magnetic sensor unit. And a plane having a normal direction in the first direction.

  According to the present disclosure, it is possible to provide a magnetic detection device capable of further increasing accuracy.

It is a block diagram which shows an example of a magnetic sensor unit provided with the full bridge circuit formed including the magnetic sensor part. It is a block diagram which shows an example of a main structure part. It is an upper surface schematic diagram which shows an example of a magnetic sensor part. It is a cross-sectional schematic diagram of the magnetic sensor part shown in FIG. It is a figure for demonstrating the main structure part. It is a figure for demonstrating the length of a magnetic convergence part. It is a figure which shows the example of 1 structure of a magnetic detection apparatus. It is a figure explaining the state to which the magnetic field was applied with the magnetic detection apparatus of FIG. It is a figure which shows the example of 1 structure of a magnetic detection apparatus. It is a figure which shows the example of 1 structure of a magnetic detection apparatus. It is a figure which shows the example of 1 structure of a magnetic detection apparatus. It is a figure which shows the example of 1 structure of a magnetic detection apparatus. It is a figure which shows the example of 1 structure of a magnetic detection apparatus. It is a figure which shows the example of 1 structure of a magnetic detection apparatus. It is a figure which shows the example of 1 structure of a magnetic detection apparatus.

  In the following detailed description, numerous specific configurations are set forth to provide a thorough understanding of the embodiments. However, it will be apparent that other embodiments may be practiced without limitation to such specific specific configurations. Further, the following embodiments do not limit the invention according to the claims, but include all combinations of characteristic configurations described in the embodiments.

[Description of each component]
(Magnetic sensor unit)
The magnetic sensor unit includes, for example, a main component and an electric circuit that generates a cancel magnetic field. The main component unit includes, for example, a magnetic sensor unit and a cancel magnetic field generation unit. The magnetic sensor unit may use a method of differentially inputting to an electric circuit using a bridge circuit for the purpose of reducing electric noise. When the magnetic sensor unit forms a bridge circuit, a general fixed resistor or variable resistor may be used. In the magnetic sensor unit, as will be described later, at least a part of the element part of the magnetic sensor part is present inside the envelope surface of the canceling magnetic field generating part.

(Magnetic sensor part)
The magnetic sensor unit is a member that has a magnetic sensing area for sensing a magnetic field and whose resistance value changes according to the input magnetic field. The magnetic sensor unit includes a substrate and an element unit formed on the substrate. The magnetic sensor unit may include a magnetic converging unit that converges an input magnetic field input to the element unit. The magnetic sensor unit may further include, for example, a protective layer, an element wiring unit, an electrode, and the like. A plurality of element portions may be formed and electrically connected by an element wiring portion. The magnetic sensor unit is not limited to the above components, and may include other components. However, the canceling magnetic field generating unit and the electric circuit for generating the canceling current are not included as components of the magnetic sensor unit.

(substrate)
The substrate is not particularly limited as long as it can be insulated from the element portion. A substrate in which an insulating film is formed over a conductive substrate may be used. As a substrate that is usually used, a substrate in which a SiO ₂ thermal oxide film is formed on glass or silicon (Si) can be cited.

(Element part)
The element part is formed on the substrate. Here, the term “on” includes not only the case where the element portion exists on the substrate but also the case where another layer is further provided between the substrate and the element portion. The interpretation of the word “above” is the same in other hierarchical relationships. In addition, the word “under” includes a case where another layer further exists.

  The element section includes a magnetization free layer, a nonmagnetic layer, and a magnetization fixed layer. In the configuration of the element portion, it is preferable that a magnetization free layer, a nonmagnetic layer, and a magnetization fixed layer are laminated in this order. However, the order of stacking in the element portion is not limited. From the viewpoint of improving sensitivity, the nonmagnetic layer is preferably formed of an insulating material.

  The element unit has a magnetosensitive axis extending in one direction. A magnetosensitive axis extending in one direction means a magnetosensitive axis in which the direction in which the sensitivity to an external magnetic field is maximized is one direction. For example, when the application direction of the external magnetic field B and the magnetosensitive axis are inclined by an angle θ, the effective magnetic field Beff felt by the magnetic sensor is represented by “B cos θ”. When θ = 0, that is, when the direction in which the external magnetic field is applied coincides with the direction of the magnetosensitive axis, the effective magnetic field is maximized, so that the external magnetic field can be detected with the highest sensitivity. In order to confirm the magnetosensitive axis, for example, a magnetic field having a constant strength at which the magnetization free layer described later is sufficiently magnetized is applied to the magnetic sensor unit while rotating, and the angular dependence of the resistance value is measured. . At this time, the direction in which the resistance is highest (or lower) is the magnetosensitive axis direction. In an embodiment described later, the element unit has a magnetosensitive axis in a direction parallel to the main surface of the substrate, and outputs a detection value corresponding to an input magnetic field component in the direction of the magnetosensitive axis. Here, the main surface of the substrate is a surface having a larger area than the other surfaces of the substrate.

  The element unit may include other layers above, below, or between the three layers (magnetization free layer, nonmagnetic layer, and magnetization fixed layer). It is preferable that a nonmagnetic cap layer is provided at the top of the element portion from the viewpoint of preventing oxidation. The nonmagnetic cap layer is preferably a conductive material such as Au or Ru from the viewpoint of connection with the wiring portion. From the viewpoint of adhesion, it is preferable to provide a metal layer such as Ti or Ta between the cap layer and the magnetization free layer or the magnetization fixed layer.

  The element portion can be formed by a known method. For example, the element portion can be formed by a sputtering method. In the case of forming a plurality of element portions, the stacked film formed over the substrate can be formed by dry etching or wet etching using a mask member formed by a photolithography method. At this time, the plurality of element portions may be arranged so as to be aligned in a direction perpendicular to the direction of the magnetic sensitive axis of the magnetic sensor portion. The shape of the element part may be controlled by stopping the etching in the middle of the element part. In this case, the layer above the layer where etching is stopped may be formed in a plurality of portions. Etching can be arbitrarily stopped. For example, the etching may stop at the timing when a part of the magnetization fixed layer and the nonmagnetic layer is formed. From the viewpoint of reducing element noise, it is preferable that the plurality of element portions are electrically connected. Moreover, it is preferable that a some element part is connected in series.

  Further, the position of the magnetization fixed layer is not limited. The magnetization distribution in the magnetization free layer changes depending on the shape of the magnetic converging portion, the shape of the magnetization free layer, and the positional relationship thereof. Therefore, the magnetization fixed layer may be disposed at an appropriate position according to the structure. In order to determine the easy axis of magnetization of the laminated film, a magnetic field may be applied during film formation parallel to the direction desired to be the easy axis of magnetization. Here, the easy magnetization axis means a direction that is easily magnetized due to the magnetic anisotropy characteristic of the magnetic material. Magnetic anisotropy is determined by shape magnetism determined by the shape of the magnetic material, shape magnetic anisotropy determined by crystal orientation, induced magnetic anisotropy caused by the arrangement of magnetic atoms, and the like. Further, the easy axis of magnetization may be determined by performing heat treatment in a magnetic field after forming the laminated film. Further, the easy axis of magnetization may be determined by processing the magnetization free layer into an elongated shape in a top view. Here, the top view means that the three layers are viewed from the three layers in the direction in which the three layers are stacked on the substrate.

  From the viewpoint of reducing the demagnetizing field and obtaining higher sensitivity, the area of the magnetization free layer is preferably larger than the area of the magnetization fixed layer. Here, the area of the magnetization free layer and the area of the magnetization fixed layer mean the area of each layer when the element portion is viewed from above. In other words, the area of the magnetization free layer and the area of the magnetization fixed layer mean the area of a plane parallel to the main surface of the substrate. When the magnetization fixed layer is formed on the magnetization free layer, the fact that the area of the magnetization free layer is larger than the area of the magnetization fixed layer further simplifies the processing process of the magnetic sensor unit.

(Magnetization free layer)
The magnetization free layer is mainly composed of a ferromagnetic material that is easily magnetized by an external magnetic field. The magnetization free layer is not limited to one composed of one material. The magnetization free layer may be a multilayer film, for example. The ferromagnetic material is, for example, NiFe, CoFeB, CoFeSiB, CoFe, NiFeSiB or the like, but is not limited thereto. The magnetization free layer is preferably a multilayer film in which a nonmagnetic layer such as Ru or Ta is inserted in the magnetization free layer in order to improve magnetic sensitivity.

  The shape of the magnetization free layer is preferably shortened in the thickness direction and lengthened in the magnetosensitive axis direction so as to obtain higher sensitivity and reduce the demagnetizing field. As a specific example, the length in the film thickness direction is preferably 200 nm or less. The length in the film thickness direction is more preferably 100 nm or less. The length in the magnetosensitive axis direction is preferably 10 μm or more. The length in the magnetosensitive axis direction is more preferably 50 μm or more. The length in the magnetic sensitive axis direction is more preferably 100 μm or more. The length in the direction perpendicular to the magnetosensitive axis and the film thickness is preferably equal to or greater than the length in the magnetosensitive axis direction in order to maintain the continuity of the sensor output. However, the magnetization free layer is not limited to such a shape.

(Nonmagnetic layer)
The nonmagnetic layer is made of an insulating nonmagnetic material. In general, in the case of a TMR element, an insulating material such as Al ₂ O ₃ or MgO is used, but this is not restrictive. In order to increase the magnetic sensitivity, it is preferable to use MgO for the nonmagnetic layer. Here, the finely processed shape of the nonmagnetic layer is not limited.

(Magnetic pinned layer)
The magnetization fixed layer is mainly composed of a ferromagnetic material so that the magnetization direction is not easily changed by an external magnetic field. The magnetization fixed layer is not limited to one composed of one material. The magnetization fixed layer may be a multilayer film, for example. As an example, the fixed magnetization layer has a structure in which a ferromagnetic material is pinned with an antiferromagnetic material. As the soft magnetic material, NiFe, CoFeB, CoFeSiB, CoFe and the like are used, but not limited thereto. In order to improve magnetic sensitivity, a multilayer film in which a nonmagnetic layer such as Ru or Ta is inserted into the magnetization fixed layer is preferable. IrMn, PtMn, or the like is used as an antiferromagnetic material, but is not limited to this configuration. Here, the finely processed shape of the magnetization fixed layer does not matter.

(Magnetic area)
The magnetic sensor unit detects magnetism based on a change in the resistance value of the magnetic sensor unit. Here, the resistance value of the magnetic sensor unit changes as the relative angle of magnetization in the region of the interface between the magnetization fixed layer and the magnetization free layer changes. That is, the region in which the resistance value changes due to magnetism is determined by the smaller of the areas of the magnetization free layer and the magnetization fixed layer in a top view. In the following, the region of the interface defined by the smaller area of the magnetization free layer and the magnetization fixed layer can be expressed as a magnetosensitive area.

  Here, in the magnetosensitive axis direction, the maximum value of the length from one end (one end, for example, the left end) to the other end (the other end, for example, the right end) of the magnetosensitive area (including all of the magnetosensitive areas) is denoted by Lj It is defined as In order to reduce the error between the magnetic field of the cancel magnetic field generation unit and the input magnetic field, it is preferable that Lj is small. Although there is a distribution in the magnetic field generated by the canceling magnetic field generator described later, when Lj is small, the difference from the uniformly input magnetic field is small in the area where the magnetic field is sensed (uniform magnetic field). This is because it becomes close to the case of sensing.

From the viewpoint of the electrical noise of the sensor itself, it is known that the electrical noise of the sensor is inversely proportional to the square root of the size of the magnetic sensitive area, and it is preferable that the size of the magnetic sensitive area is large. Specifically, the magnetosensitive area size is preferably 100 μm ² or more. The magnetic sensitive area size is more preferably 1000 μm ² or more.

(Magnetic convergence part)
The magnetic converging portion is made of a soft magnetic material. Examples of the soft magnetic material include, but are not limited to, NiFe, CoFeSiB, NiFeCuMo, CoZrNb, and NiFeNb. Since the closer the magnetic converging part and the element part are, the more effective magnetic amplification is possible. Therefore, it is preferable that a part of the magnetic converging part is produced close to the element part by a fine processing process such as sputtering or plating. . Further, it is formed by plating or the like and is further away from the element part in the magnetic sensitive axis direction, in which a magnetic converging part (first soft magnetic body) close to the element part in the magnetic sensitive axis direction and a commercially available soft magnetic thin film are further bonded. You may utilize combining the magnetic converging part produced separately, such as a magnetic converging part (2nd soft magnetic body). At this time, from the viewpoint of effective magnetic convergence, (film thickness Tfr of the magnetization free layer) <(film thickness Tfc1 of the magnetic convergence part close to the element part) <(film thickness Tfc2 of the magnetic convergence part far from the element part) It is preferable that Further, the second soft magnetic body may be disposed so as to be in direct contact with the first soft magnetic body, or indirectly with the first soft magnetic body with another material (for example, another thin film) interposed therebetween. It may be arranged so that it touches. However, from the viewpoint of more effective magnetic amplification, the second soft magnetic body is preferably in direct contact with the first soft magnetic body.

  In the magnetic sensor, in order to obtain higher sensitivity, it is preferable that the demagnetizing field in the direction of the magnetosensitive axis of the magnetic converging portion is small as in the case of the magnetization free layer. In order to reduce the demagnetizing field, it is preferably a thin film and long in the magnetosensitive axis direction. However, if the film thickness is too thin, the magnetization of the magnetic converging part itself tends to increase, but the magnetic field attenuation in the space becomes intense, so the magnetic field flowing into the element part becomes small. That is, effective magnetic amplification cannot be performed. Therefore, it is preferable to have a certain thickness. Specifically, the thickness Tfc of the magnetic converging portion is preferably larger than the thickness Tfr of the magnetization free layer. Of the thickness Tfc of the magnetic converging portion, the thickness Tfc1 of the magnetic converging portion close to the element portion is preferably included in the range of 1 μm to 500 μm. It is preferably included in the range of 10 mm. The numerical value is not limited to this because the effect of the demagnetizing field varies depending on the shape such as the length and width of the magnetic converging portion. Further, the thickness Tfr of the magnetization free layer and the thickness Tfc of the magnetic converging portion can take a plurality of values. It is preferable that the minimum thickness Tfr of the magnetization free layer is smaller than the maximum thickness Tfc of the thickness of the magnetic converging portion.

  From the viewpoint of efficient magnetic amplification, the distance Dfcfr between the magnetic converging portion and the magnetization free layer is preferably small in the direction of the magnetic sensitive axis. The interval of Dfcfr that can be effectively magnetically amplified varies depending on the thickness Tfc of the magnetic converging portion, and is preferably smaller than the value of the thickness Tfc of the magnetic converging portion. Specifically, it is preferable that Dfcfr <Tfc. In order to obtain higher sensitivity in the magnetic sensor, it is preferable to form the element portion so as to exist in a region sandwiched between the plurality of magnetic converging portions in a top view. The magnetic converging part may overlap with a part of the element part in a top view. When the magnetic converging part overlaps with a part of the element part, Dfcfr can take a negative value. Further, the distance Dfcfr between the magnetic converging portion and the magnetization free layer can take a plurality of values. It is preferable that the minimum distance Dfcfr in the top view is smaller than 5 times the film thickness (thickness Tfc) of the magnetic convergence portion.

  In addition, the magnetic converging portion preferably has a shape satisfying the second length <third length <first length from the viewpoint of efficient magnetic amplification. This is because when the first length, the second length, and the third length satisfy this relationship, the demagnetizing field can be further reduced. Here, the first length is a length connecting both ends in the direction of the magnetosensitive axis of the magnetic converging portion. The second length is the maximum length in the direction perpendicular to the main surface of the substrate of the magnetic converging part, and corresponds to the thickness Tfc of the magnetic converging part. The third length is a length connecting both ends in the direction of the magnetosensitive axis of the magnetic converging portion and the direction perpendicular to the thickness direction.

  Moreover, the magnetic converging part may be arrange | positioned at the both sides of an element part in the direction parallel to a magnetosensitive axis. In addition, the interval between the magnetic focusing portions arranged on both sides of the element portion in the direction of the magnetic sensitive axis may be smaller than the length of the magnetic free layer in the direction of the magnetic sensitive axis.

(Protective layer)
The protective layer is used to maintain insulation of the element portion, the element wiring portion, the magnetic converging portion, and the like. The material of the protective layer is not particularly limited as long as it can insulate the element portion, the element wiring portion, and the magnetic converging portion, and examples thereof include silicon oxide, silicon nitride, and aluminum oxide. The protective layer is formed so as to cover the entire surface of the element portion, and a conductive window (that is, an opening portion) is formed on the junction portion between the element portion and the element wiring portion, and on the electrode continuously formed on the element wiring portion. ) Exists. The position and shape of the energizing window are not limited.

(Element wiring part)
The element wiring part connects the electrode and the element part via an energization window formed on the insulating layer. When a plurality of magnetic sensor units are connected in series or in parallel, the element wiring unit is used to electrically connect the element units. From the viewpoint of adhesion, it is preferable that a layer such as Ti or Ta is provided between the cap layer and the element wiring portion. As a material for the element wiring part, any conductive material (for example, Au, Cu, Cr, Ni, Al, Ta, Ru, etc.) capable of electrically connecting the element parts to each other and between the electrodes may be used. There is no particular limitation. The element wiring portion may be formed of a single material, or may be formed by mixing or laminating a plurality of materials. The element wiring portion can be formed by a known method. For example, a conductive material is formed on the entire surface of the mask member and the element portion formed by a photolithography method by vapor deposition or sputtering. It can be formed by peeling the mask member using a peeling solution (that is, lift-off method).

(electrode)
The electrode is used for connection or the like when configuring an electric circuit. From the viewpoint of adhesion, it is preferable to provide a layer of Ti, Ta or the like between the substrate and the electrode. The element part may be left on the substrate, and the electrode may be formed on the upper part. The material of the electrode is not particularly limited as long as it is a conductive material (for example, Au, Cu, Cr, Ni, Al, Ta, Ru, etc.), as in the case of the element wiring portion, but is not easily oxidized from the viewpoint of element characteristics. A material (Au, Ru, etc.) is preferred. The electrode may be formed of a single material, and may be a mixture or stack of a plurality of materials. The electrode can be formed by a known method. For example, a conductive material is formed on the entire surface of a mask member and a laminated portion formed by a photolithography method by a vapor deposition method or a sputtering method. The mask member can be peeled off using (that is, the lift-off method). From the viewpoint of process man-hours, it is preferable to fabricate simultaneously with the element wiring portion.

(Cancellation magnetic field generator)
The cancellation magnetic field generation unit is used to generate a cancellation magnetic field for reducing the input magnetic field by causing a feedback current to flow based on the magnetic field value (detection value) detected by the magnetic sensor unit. When generating the canceling magnetic field, the input magnetic field can be detected by detecting the value of the feedback current that has flowed. Since the cancel magnetic field is formed so as to cancel the input magnetic field from the outside, the magnetic field applied to the element portion is always constant until the feedback current reaches the maximum value that can be passed through the electric circuit. Therefore, the measurable magnetic field range is not a magnetic field in which the element itself saturates, but depends on the shape of the canceling magnetic field generating unit through which the feedback current flows and the maximum value of the current that can be passed.

  The magnetic sensitivity and measurable magnetic field range of a spin-valve MR magnetic sensor have a trade-off relationship, but the trade-off between magnetic sensitivity and measurable magnetic field range should be eliminated by combining the cancel magnetic field generator and the magnetic sensor unit. Can do. The cancel magnetic field generator can be formed by winding an electric wire (an example of a conductor) around a non-magnetic material like a solenoid coil or a Helmholtz coil. As the nonmagnetic material, a metal such as Al and a resin material can be used. In an embodiment to be described later, the canceling magnetic field generation unit is formed by winding a conductor in a coil shape with a direction substantially parallel to the magnetosensitive axis as a winding axis.

  As is well known, the conversion ratio between the current and the magnetic field can be determined by adjusting the number of windings of the electric wire. The shape of the nonmagnetic material is not particularly limited as long as the electric wire can be wound uniformly. As long as it is electrically insulated, the non-magnetic material is not used, and the electric wire may be wound directly around the magnetic sensor unit. If the cancel magnetic field generation unit is insulated from the magnetic sensor unit via an insulating protective layer or the like, the cancellation magnetic field generation unit may be manufactured close to the magnetic sensor unit by sputtering or frame plating. The cross-sectional shape of the canceling magnetic field generating part created by winding is not limited as long as the magnetic sensor part can be arranged inside. From the viewpoint of ease of production, a circle, an ellipse, or a polygon is preferable.

  For example, in the case of a general solenoid coil, the magnetic field generated by the canceling magnetic field generating unit has a spatial distribution in which the central magnetic field is the highest and becomes smaller as it approaches the end. Ideally, the feedback magnetic field matches the input magnetic field, but in reality, there is a spatial distribution of the magnetic field as described above. In order to improve the magnetic sensitivity by making the distribution of the feedback magnetic field as close as possible to the distribution of the input magnetic field, it is preferable to detect magnetism in a minute region where the feedback magnetic field can be regarded as almost constant. For this reason, it is preferable that at least a part of the magnetic concentrating portion arranged on the center of gravity of the magnetic sensing area and on both sides of the element portion is arranged inside the envelope surface of the canceling magnetic field generating unit. Here, the envelope surface of the canceling magnetic field generating unit means a surface constituting a virtual solid formed by connecting the outer shapes of the canceling magnetic field generating unit. For example, when the canceling magnetic field generating unit is formed by winding a conductor in a coil shape, the envelope surface includes a cylindrical surface that forms a cylinder formed by connecting the coiled conductor. Further, in this example, when the coiled conductor is physically divided into a plurality, the envelope surface can be configured to include the plurality of coiled conductors.

  The length of the magnetic sensing area in the winding axis direction is preferably smaller than the length of the canceling magnetic field generating unit in the winding axis direction. As long as the magnetosensitive areas are symmetrically arranged with respect to the central axis of the cancel magnetic field generation unit, all of the magnetosensitive areas do not have to exist inside the envelope surface of the cancel magnetic field generation unit. However, from the viewpoint of further improving the linearity, it is preferable that all the magnetic sensitive areas are arranged inside the envelope surface of the cancel magnetic field generation unit. Moreover, in order to suppress the whole size, it is preferable that the magnetic sensor unit is covered with the cancel magnetic field generation unit.

  Moreover, it is preferable that the maximum length Lj of the magnetic sensitive area in the magnetic sensitive axis direction is sufficiently smaller than the length Lc of the canceling magnetic field generating portion in the magnetic sensitive axis direction. Specifically, it is preferable that Lc / Lj> 5. Further, it is more preferable that Lc / Lj> 50. Further, it is more preferable that Lc / Lj> 100.

  In addition, since the magnetic field distribution of the canceling magnetic field generating unit is the smallest near the center of gravity of the canceling magnetic field generating unit, in order to suppress the magnetic field distribution in the magnetic sensitive area and obtain higher linearity, the magnetic sensitive area It is preferable that the center of gravity position of and the center of gravity of the canceling magnetic field generating unit coincide with each other. Here, when a plurality of magnetic sensitive areas are provided, the position of the center of gravity of the magnetic sensitive area is the total center of gravity of the plurality of magnetic sensitive areas. Further, the gravity center position of the magnetic sensing area and the gravity center position of the canceling magnetic field generation unit do not have to be completely coincident with each other, and may be substantially coincident (substantially coincide). The allowable deviation of the center of gravity position is, for example, 1/10 or less of the length Lc of the canceling magnetic field generating portion in the magnetosensitive axis direction, but is not limited to this. In the present embodiment, the center of gravity of the canceling magnetic field generator is defined as “the center of gravity of the magnetic sensor unit”.

(electric circuit)
The electric circuit applies a feedback current based on a detection value corresponding to the input magnetic field component to the cancel magnetic field generation unit, thereby causing the cancel magnetic field generation unit to generate a cancel magnetic field that attenuates the input magnetic field. The electric circuit may include a general operational amplifier. For example, by connecting the output of the operational amplifier so as to generate a magnetic field in the opposite direction to the input magnetic field to the cancel magnetic field generation unit, the magnetic field detected by the magnetic sensor unit is killed and operates so as to be balanced. The electric circuit may be configured using two or more operational amplifiers.

  For the purpose of reducing electromagnetic noise, it is preferable to amplify the signal using an operational amplifier after shortening the wiring from the magnetic sensor unit to the electric circuit and applying an electromagnetic shield. For the purpose of reducing high frequency noise, a low pass filter may be used. For the purpose of cutting DC noise, a high pass filter may be used. As a current detector, it is convenient to arrange a resistor and measure the voltage at both ends.

(Resistor)
As the resistor, a general metal film resistor or a chip resistor can be used. From the viewpoint of reducing the size, it is preferable to use a chip resistor. The resistor may be a variable resistor. A digital potentiometer that can control the value of the variable resistor based on the input value may be provided. Whichever resistor is used, it is desirable that the circuit noise is small.

(Magnetic detection device)
The magnetic detection device includes a plurality of magnetic sensor units. As described above, the magnetic sensor unit includes the magnetic sensor unit including the substrate and the element unit, the cancel magnetic field generation unit, and the electric circuit. The configuration of the magnetic detection device according to some embodiments will be described below with reference to the drawings.

[First Embodiment]
(Configuration and manufacturing method of magnetic sensor unit)
FIG. 1 is a schematic configuration diagram illustrating an example of a magnetic sensor unit 1000 included in the magnetic detection device according to the first embodiment. The magnetic sensor unit 1000 includes a bridge circuit formed by the magnetic sensor unit 11 and the resistors 81 to 83. FIG. 2 is a schematic configuration diagram illustrating an example of the main configuration unit 100 of the magnetic sensor unit 1000. In the present embodiment, the main component unit 100 includes a magnetic sensor unit 11 and a cancel magnetic field generation unit 70. 2 schematically shows the element part of the magnetic sensor part 11. In FIG. Further, FC in FIG. 2 schematically shows a magnetic converging part of the magnetic sensor part 11. Moreover, the coil part of FIG. 2 shows the cancellation magnetic field generation | occurrence | production part 70 typically.

  In the bridge circuit of the magnetic sensor unit 1000, the positive side (+) of the power source, the resistor 81, the magnetic sensor unit 11, and the negative side (−) of the power source are connected in this order. In the bridge circuit, the positive side (+) of the power source, the resistor 82, the resistor 83, and the negative side (−) of the power source are connected in this order. As shown in FIG. 1, the bridge circuit includes a resistor group having a terminal T1 at a connection point between the resistor 81 and the magnetic sensor unit 11, and a resistor having a terminal T2 at a connection point between the resistor 82 and the resistor 83. An instrument group is connected in parallel.

  The signal at the terminal T1 and the signal at the terminal T2 are input to an operational amplifier AMP as an electric circuit. The output of the operational amplifier AMP is connected to one end of the cancel magnetic field generator 70. Further, the other end of the canceling magnetic field generation unit 70 is grounded via a current detector 90.

  With this configuration, the magnetic sensor unit 1000 supplies a signal from the bridge circuit including the magnetic sensor unit 11 to the cancel magnetic field generation unit 70 via an electric circuit including the operational amplifier AMP. The magnetic sensor unit 1000 detects the intensity of the input magnetic field by reading the detection current of the current detector 90 as a current value corresponding to the amount of the magnetic field applied to the magnetic sensor unit 11.

  FIG. 3 is a schematic top view illustrating an example of the magnetic sensor unit 11. FIG. 4 is a schematic view showing the AA cross section of FIG. Here, in FIG. 3, some elements of the magnetic sensor unit 11 are illustrated. For example, the substrate 10 and the protective layer are not shown in FIG.

  As shown in FIGS. 3 and 4, the magnetic sensor unit 11 is formed on the substrate 10, the element unit 20 disposed on the substrate 10, the protective layer 40 covering the element unit 20, and the protective layer 40. The element wiring part 50 connected with the element part 20 through the electricity supply window 40a, and the protective layer 41 which covers the element wiring part 50 and the protective layer 40 are provided. Further, the magnetic sensor unit 11 includes a magnetic converging unit 30 on the protective layer 41 via the seed layer 31.

  Here, the element unit 20 and the magnetic converging unit 30 are arranged so as to be aligned along the magnetosensitive axis in a top view.

  In the element unit 20, a magnetization free layer 21, a nonmagnetic layer 22, and a magnetization fixed layer 23 are laminated in this order. Specifically, a plurality of stacked bodies formed of the nonmagnetic layer 22 and the magnetization fixed layer 23 are formed on one magnetization free layer 21. The plurality of stacked bodies are arranged along a line that is substantially orthogonal to one direction (the direction of the magnetosensitive axis of the element unit 20) among the sides that define the magnetic converging unit 30. In FIG. 3, two stacked bodies formed of a nonmagnetic layer 22 and a magnetization fixed layer 23 are disposed on one magnetization free layer 21.

  FIG. 5 is a diagram for explaining the configuration of the main configuration unit 100. Apart from the magnetic sensor unit 11, a cancel magnetic field generating unit 70 formed by winding an electric wire around a nonmagnetic material is prepared. As shown in FIG. 5, the magnetic sensor unit 11 is included in the cancel magnetic field generation unit 70 so that the magnetic sensing axis direction of the magnetic sensor unit 11 and the winding axis of the cancel magnetic field generation unit 70 are substantially parallel. In combination, the main component 100 is configured.

  Here, FIG. 6 is a diagram for explaining the length of the magnetic converging unit 30, and is a schematic top view illustrating another example of the magnetic sensor unit 11. In the example of FIG. 6, a magnetization free layer 21 and two magnetosensitive areas 230 are shown. In the example of FIG. 6, since the area of the magnetization fixed layer 23 is smaller than the magnetization free layer 21, the magnetosensitive area 230 is determined by the area of the magnetization fixed layer 23. The magnetic converging portions 30 are disposed on both sides of the element portion including the magnetization free layer 21 and the magnetization fixed layer 23 in a direction parallel to the magnetosensitive axis. Here, the shape and size of the two magnetic flux concentrators 30 arranged on both sides are the same. The magnetic flux concentrator 30 has a first length Lfc that is a length connecting both ends in the direction of the magnetosensitive axis. Further, as shown in FIG. 4, the magnetic flux concentrator 30 has a second length that is the maximum length in the direction perpendicular to the main surface of the substrate 10. The second length corresponds to the thickness Tfc of the magnetic flux concentrator 30. Magnetic converging portion 30 has a third length Wfc that is a length (width) connecting both ends in the direction perpendicular to the direction of the magnetosensitive axis and the direction perpendicular to the main surface of substrate 10. In the present embodiment, the magnetic flux concentrator 30 satisfies the second length (thickness Tfc) <third length Wfc <first length Lfc.

  In the example of FIG. 6, the two magnetic sensitive areas 230 each have a center of gravity g1 and a center of gravity g2. At this time, the position of the center of gravity of the magnetic sensor unit 1000 is the center of gravity G of the entire plurality of magnetic sensitive areas 230. In the present embodiment, the position of the center of gravity of the entire magnetosensitive area 230 matches the position of the center of gravity of the canceling magnetic field generating unit 70. That is, the center of gravity position of the canceling magnetic field generating unit 70 is the center of gravity G.

  Here, the main component 100 can be manufactured by the following manufacturing method, for example. First, a laminated film formed of a ferromagnetic layer and a nonmagnetic layer is formed on the substrate 10 by a known method such as sputtering. Next, a mask member is formed on the laminated film by a photolithography method or the like. The mask member can be formed in a desired shape at a desired location on the laminated film.

  Next, the portion of the laminated film not covered with the mask member is etched by a known method such as ion milling. Thereby, the laminated film on the substrate 10 is processed into a desired planar shape. At this time, a plurality of laminated films (laminated portions) processed into a desired planar shape may be present in the plane of the substrate 10.

  Next, a mask member is formed on the laminated portion by a photolithography method or the like. At this time, the opening of the mask member is formed to be smaller than the plane area of the stacked portion. Next, the laminated portion not covered with the mask member is etched by a known method such as ion milling. At this time, etching is stopped near the nonmagnetic layer in the “ferromagnetic layer / nonmagnetic layer / ferromagnetic layer” structure existing in the laminated film. Here, the lower ferromagnetic layer may be partially etched. Thereby, the dimension in one direction of the nonmagnetic layer / ferromagnetic layer not in contact with the substrate 10 is formed smaller than that in the ferromagnetic layer in contact with the substrate 10. As a result, the element unit 20 including the magnetization free layer 21 formed of a ferromagnetic layer, the nonmagnetic layer 22, and the magnetization fixed layer 23 formed of a ferromagnetic layer is formed on the substrate 10.

  Next, an insulating film is formed on the element portion 20 by a known method such as a CVD (Chemical Vapor Deposition) method. A mask member is formed on the insulating film by a photolithography method or the like. Further, the insulating film is etched by a known method such as RIE (Reactive Ion Etching) to form an opening for the conduction window 40a. Thereby, the protective layer 40 having the energization window 40a is formed.

  Next, a mask member is formed on the protective layer 40 by a photolithography method or the like. Further, a metal thin film is formed by a known method such as sputtering. The element wiring part 50 is formed by removing the mask member and the metal thin film on the mask member.

  Furthermore, a protective layer 41 is formed to insulate the magnetic flux concentrator 30 and the seed layer 31 by a known method such as sputtering.

  Further, a seed layer 31 as a plating base is formed by a known method such as sputtering.

  Further, a mask member is formed on the seed layer 31 by a photolithography method or the like. Next, by forming a plating film on the opening of the mask member by a known method such as electrolytic plating, the mask member is removed after the magnetic converging portion 30 is formed. Next, the seed layer 31 and the protective layer 40 (other than the portion existing between the magnetic converging portion 30 and the protective layer 40) covering the entire surface are removed by a known method such as ion milling.

  Through the above steps, the magnetic sensor unit 11 shown in FIGS. 3 and 4 can be obtained. And the main structure part 100 shown in FIG. 5 can be obtained by combining and fixing the magnetic sensor part 11 and the cancellation magnetic field generation part 70 as mentioned above. As shown in FIG. 1, the main component 100 configured in this way forms a bridge circuit and is combined with an electric circuit such as an operational amplifier to constitute a magnetic sensor unit 1000.

(Configuration and manufacturing method of magnetic detection device)
FIG. 7 is a diagram illustrating a configuration example of the magnetic detection device 1 according to the present embodiment. The magnetic detection device 1 includes a plurality of magnetic sensor units 1000. In the present embodiment, the magnetic detection device 1 includes a first magnetic sensor unit 1000a, a second magnetic sensor unit 1000b, a third magnetic sensor unit 1000c, and a fourth magnetic sensor unit 1000d.

  The first magnetic sensor unit 1000a and the second magnetic sensor unit 1000b are arranged side by side in the first direction so that the direction of the magnetosensitive axis is the first direction. Here, the first magnetic sensor unit 1000a and the second magnetic sensor unit 1000b may be arranged at a predetermined interval. Between the first magnetic sensor unit 1000a and the second magnetic sensor unit 1000b, there may be constituent materials other than the magnetic sensor unit, such as a printed board and a magnetic body. In the example of FIG. 7, the first direction is the x-axis direction. The third magnetic sensor unit 1000c and the fourth magnetic sensor unit 1000d are arranged side by side in the second direction so that the direction of the magnetosensitive axis is the second direction. In the example of FIG. 7, the first direction is the y-axis direction. In the example of FIG. 7, the first direction (x-axis direction) and the second direction (y-axis direction) are orthogonal to each other. Here, the first direction and the second direction do not have to be strictly orthogonal. That is, the first direction and the second direction may be substantially orthogonal.

  As shown in FIG. 7, the first magnetic sensor unit 1000a has a center of gravity Ga. The second magnetic sensor unit 1000b has a center of gravity Gb. The third magnetic sensor unit 1000c has a center of gravity Gc. The fourth magnetic sensor unit 1000d has a center of gravity Gd. In the example of FIG. 7, the coordinates of the center of gravity Ga are indicated by ((−D / 2), 0). The coordinates of the center of gravity Gb are indicated by ((+ D / 2), 0). The coordinates of the center of gravity Gc are indicated by (0, (−D / 2)). The coordinates of the center of gravity Gd are indicated by (0, (+ D / 2)). Adjacent magnetic sensor units 1000 arranged side by side in the x-axis direction are separated by a distance D in the x-axis direction. Adjacent magnetic sensor units 1000 arranged side by side in the y-axis direction are separated by a distance D in the y-axis direction. The distance D is 20 mm as an example.

  Here, when an MR sensor combined with a coil is used as one magnetic sensor and a plurality of magnetic sensors are arranged close to each other, a magnetic flux generated in the coil draws a loop, and in addition to an external input magnetic field, a certain magnetic sensor Since a magnetic field generated from a coil of another magnetic sensor arranged in the vicinity of the magnetic sensor is mixed, signal crosstalk occurs between the magnetic sensors. Here, the signal crosstalk means that a part of the signal component of one magnetic sensor is mixed in the signal of another magnetic sensor. For example, when magnetic sensors with different magnetic sensing directions are arranged close to each other, an accurate signal component may not be obtained due to crosstalk from a magnetic sensor on the other axis that is not in the sensitivity axis direction with respect to one sensor. was there.

  FIG. 8 is a diagram for explaining a state in which a magnetic field is applied in the magnetic detection device 1 shown in FIG. In the example of FIG. 8, an external input magnetic field Bx (hereinafter referred to as an external magnetic field Bx) is applied to the magnetic detection device 1 in a positive direction in the x-axis direction. The closed-loop first magnetic sensor unit 1000a passes a feedback current to the cancel magnetic field generator 70 in order to detect the external magnetic field Bx. At this time, the first magnetic sensor unit 1000a generates the magnetic field Bcx1 by the feedback current. The magnetic field Bcx1 has a position dependency in which the intensity varies according to the distance from the first magnetic sensor unit 1000a. For example, the magnetic field Bcx1 generated at the position of the fourth magnetic sensor unit 1000d is affected by the intensity of pBcx1. Here, p is a coefficient indicating position dependency. In the fourth magnetic sensor unit 1000d, crosstalk can be generated by the magnetic field Bcx1 generated in the first magnetic sensor unit 1000a of the other axis (different in the magnetic sensitive axis).

  In the example of FIG. 8, the closed-loop second magnetic sensor unit 1000b passes a feedback current to the cancel magnetic field generation unit 70 in order to detect the external magnetic field Bx. At this time, the second magnetic sensor unit 1000b generates the magnetic field Bcx2 by the feedback current. For example, the magnetic field Bcx2 generated at the position of the fourth magnetic sensor unit 1000d is affected by the intensity of qBcx2. Here, q is a coefficient indicating position dependency. In the fourth magnetic sensor unit 1000d, crosstalk can occur due to the magnetic field Bcx2 generated in the second magnetic sensor unit 1000b of the other axis (different in the magnetic sensitive axis).

  Here, the first magnetic sensor unit 1000a and the second magnetic sensor unit 1000b have the same configuration. The first magnetic sensor unit 1000a and the second magnetic sensor unit 1000b both generate a magnetic field by a feedback current so as to cancel the external magnetic field Bx. That is, Bx = −Bcx1 = −Bcx2 holds with respect to the magnetosensitive axis direction (x-axis direction) of the first magnetic sensor unit 1000a and the second magnetic sensor unit 1000b.

  In addition, the first magnetic sensor unit 1000a and the second magnetic sensor unit 1000b are arranged at positions that are line-symmetric with respect to the y-axis where the fourth magnetic sensor unit 1000d is located. Therefore, p = −q holds for the coefficient p and the coefficient q.

  Therefore, the magnetic field Bcx1 generated by the first magnetic sensor unit 1000a at the position of the fourth magnetic sensor unit 1000d is canceled by the magnetic field Bcx2 generated by the second magnetic sensor unit 1000b. Similarly, it occurs in the magnetic sensor unit 1000 of the other axis (different in the magnetic sensitive axis) at the positions of the first magnetic sensor unit 1000a, the second magnetic sensor unit 1000b, and the third magnetic sensor unit 1000c. The effect of the applied magnetic field is cancelled.

  Here, the magnetic field Bcx1 and the magnetic field Bcx2 may not completely coincide with each other due to, for example, individual differences in manufacturing between the first magnetic sensor unit 1000a and the second magnetic sensor unit 1000b or an error in the arrangement position. Even in this case, since the magnetic field Bcx1 and the magnetic field Bcx2 cancel at least partially at the position of the fourth magnetic sensor unit 1000d, signal crosstalk is reduced. The difference between the magnetic field Bcx1 and the magnetic field Bcx2 due to individual differences in manufacturing is strongly influenced by the offset component of the feedback current. In order to reduce crosstalk more effectively, the electric circuit of each magnetic sensor unit 1000 preferably has a function of adjusting the offset value of the feedback current. For example, the electric circuit of each magnetic sensor unit 1000 may include a circuit that increases or decreases the feedback current by an amount corresponding to the offset value. By setting an appropriate offset value in the electric circuit of each magnetic sensor unit 1000, for example, even when there is an individual difference or the like, it is possible to cancel the magnetic field generated in the magnetic sensor unit 1000 on the other axis. Here, the offset value is determined by the difference in voltage between Ta and Tb in the bridge circuit of FIG. In order to reduce the voltage difference between Ta and Tb, for example, the background Ta and Tb output difference in the measurement environment is stored in an external memory or the like, and attached as one of the resistors based on the stored value. You may set the resistance value of the digital potentiometer.

  Further, in the magnetic detection device 1 according to the present embodiment, the position of the magnetic sensor unit 1000 is as shown in FIG. 7 if the influence of the magnetic field generated in the magnetic sensor unit 1000 of the other axis (different in the magnetic sensitive axis) is canceled. May be different. In the example of FIG. 7, a plurality of magnetic sensor units 1000 having the same direction of the magnetosensitive axis are arranged side by side on one axis parallel to the direction of the magnetosensitive axis. That is, the magnetic sensor unit 1000 is arranged along the x axis or the y axis. Here, the center of gravity G of the magnetic sensor unit 1000 does not have to be on the x-axis or the y-axis, and may be arranged by being shifted by a distance Δd. The distance Δd is set to a value smaller than the arrangement interval of the magnetic sensor units 1000. For example, the distance Δd is a value of D / 2 or less. Here, the value of the distance Δd is preferably D / 4 or less, more preferably D / 8 or less, and further preferably D / 16 or less. The direction of deviation may be along the x-axis or y-axis direction, or may not be along the axis direction. When the intersection of the x axis and the y axis is (0, 0), the coordinates of the center of gravity Ga are ((−D / 2) ± Δd, ± Δd). The coordinates of the center of gravity Gb are ((+ D / 2) ± Δd, ± Δd). The coordinates of the center of gravity Gc are (± Δd, (−D / 2) ± Δd). The coordinates of the center of gravity Gd are (± Δd, (+ D / 2) ± Δd). The example of FIG. 7 corresponds to the case where the distance Δd is 0.

  That is, the magnetic detection apparatus 1 according to the present embodiment has the following positional relationship on a plane (for example, the xy plane) including the first direction (for example, the x-axis direction) and the second direction (for example, the y-axis direction). Have The first magnetic sensor unit 1000a and the second magnetic sensor unit 1000b are arranged between the center of gravity of the third magnetic sensor unit 1000c and the center of gravity of the fourth magnetic sensor unit 1000d in the second direction. In other words, when the center of gravity of the first to fourth magnetic sensor units is projected in the second direction, the center of gravity of the first magnetic sensor unit 1000a and the center of gravity of the second magnetic sensor unit 1000b are the third magnetism. It is located between the center of gravity of the sensor unit 1000c and the center of gravity of the fourth magnetic sensor unit 1000d. In addition, the first magnetic sensor unit 1000a and the second magnetic sensor unit 1000b have a line segment connecting the center of gravity of the third magnetic sensor unit 1000c and the center of gravity of the fourth magnetic sensor unit 1000d in the first direction ( For example, they are arranged on opposite sides with respect to the y axis).

  The third magnetic sensor unit 1000c and the fourth magnetic sensor unit 1000d are arranged between the center of gravity of the first magnetic sensor unit 1000a and the center of gravity of the second magnetic sensor unit 1000b in the first direction. The Further, the third magnetic sensor unit 1000c and the fourth magnetic sensor unit 1000d have a line segment connecting the center of gravity of the first magnetic sensor unit 1000a and the center of gravity of the second magnetic sensor unit 1000b in the second direction ( For example, they are arranged on opposite sides with respect to the x axis).

  Here, the magnetic detection device 1 can be manufactured by the following manufacturing method, for example. First, the bridge circuit and the electric circuit constituting the first magnetic sensor unit 1000a are manufactured by wiring with a printed board. The magnetic sensor units 1000b to 1000d are similarly manufactured. Next, the magnetic sensor units 1000a to 1000d are fixed to the holding base. The holding base may be non-magnetic and is made of a material such as resin or aluminum. At this time, the first magnetic sensor unit 1000a and the second magnetic sensor unit 1000b are arranged between the center of gravity of the third magnetic sensor unit 1000c and the center of gravity of the fourth magnetic sensor unit 1000d in the second direction. To be fixed. In addition, the first magnetic sensor unit 1000a and the second magnetic sensor unit 1000b have a line segment connecting the center of gravity of the third magnetic sensor unit 1000c and the center of gravity of the fourth magnetic sensor unit 1000d in the first direction ( For example, they are fixed so as to be arranged on opposite sides with respect to the y axis).

[Second Embodiment]
FIG. 9 is a diagram illustrating a configuration example of the magnetic detection device 1 according to the second embodiment. The magnetic detection device 1 includes a plurality of magnetic sensor units 1000. In the present embodiment, the magnetic detection device 1 includes a first magnetic sensor unit 1000a to a tenth magnetic sensor unit 1000j. The configuration of the magnetic sensor unit 1000 included in the magnetic detection device 1 according to the present embodiment is the same as that of the first embodiment. In addition, the magnetic detection device 1 according to the present embodiment can be manufactured by a manufacturing method similar to the first embodiment. Therefore, description of the configuration of the magnetic sensor unit 1000 and the method for manufacturing the magnetic detection device 1 according to the present embodiment will be omitted.

  In addition to the first direction (for example, the x-axis direction) and the second direction (for example, the y-axis direction), the magnetic detection device 1 according to the present embodiment has a third direction (for example, the z-axis direction) orthogonal thereto. The magnetic sensor unit 1000 is disposed in FIG. 9 is a perspective view showing the magnetic detection device 1 according to the present embodiment. Here, the third direction does not have to be strictly orthogonal to the first direction and the second direction. That is, the third direction may be substantially orthogonal to the first direction and the second direction.

  In the example of FIG. 9, two xy planes (plane s1 and plane s2) including the x-axis direction that is the first direction and the y-axis direction that is the second direction are shown. In each of the plane s1 and the plane s2, the magnetic detection device 1 has the same configuration as that of the first embodiment. For example, on the plane s2, the seventh magnetic sensor unit 1000g and the eighth magnetic sensor unit 1000h are arranged side by side in the x-axis direction so that the direction of the magnetosensitive axis is the x-axis direction. The ninth magnetic sensor unit 1000i and the tenth magnetic sensor unit 1000j are arranged side by side in the y-axis direction so that the direction of the magnetosensitive axis is the y-axis direction.

  And as shown in FIG. 9, the magnetic detection apparatus 1 contains the 5th magnetic sensor unit 1000e arrange | positioned so that the direction of a magnetosensitive axis may be a z-axis direction. In the plane s1, the center of gravity Ge of the fifth magnetic sensor unit 1000e projected onto the plane s1 is arranged between the center of gravity of the third magnetic sensor unit 1000c and the center of gravity of the fourth magnetic sensor unit 1000d in the y-axis direction. Is done. In the plane s1, the center of gravity Ge of the fifth magnetic sensor unit 1000e projected onto the plane s1 is between the center of gravity of the first magnetic sensor unit 1000a and the center of gravity of the second magnetic sensor unit 1000b in the x-axis direction. Placed in. Since the magnetic detection device 1 includes the fifth magnetic sensor unit 1000e having the z-axis direction as the magnetosensitive axis, the magnetic detection device 1 functions as a three-axis sensor and has a wide range of uses.

  As shown in FIG. 9, the magnetic detection device 1 includes a sixth magnetic sensor unit 1000 f arranged so that the direction of the magnetosensitive axis is the z-axis direction. A line segment connecting the center of gravity Ge of the fifth magnetic sensor unit 1000e and the center of gravity Gf of the sixth magnetic sensor unit 1000f has an intersection with the plane s1. In the example of FIG. 9, the center of gravity Gf of the sixth magnetic sensor unit 1000f is plane-symmetric with respect to the center of gravity Ge of the fifth magnetic sensor unit 1000e with respect to the plane s1. Here, the adjacent magnetic sensor units 1000 arranged side by side in the z-axis direction may be separated by a distance D in the z-axis direction. The distance D can take the same value as in the first embodiment.

  Here, when the external magnetic field Bx is applied, the magnetic detection device 1 shown in FIG. 9 generates a magnetic field as described below. For example, at the position of the fourth magnetic sensor unit 1000d, as described above, the magnetic field generated by the first magnetic sensor unit 1000a is canceled by the magnetic field generated by the second magnetic sensor unit 1000b. Similarly, at the position of the fourth magnetic sensor unit 1000d, the magnetic field generated by the fifth magnetic sensor unit 1000e is canceled by the magnetic field generated by the sixth magnetic sensor unit 1000f. Similarly, at the positions of the first magnetic sensor unit 1000a to the third magnetic sensor unit 1000c, the fifth magnetic sensor unit 1000e, and the sixth magnetic sensor unit 1000f, the other axis (the magnetic sensitive axis is The influence of the magnetic field generated in the (different) magnetic sensor unit 1000 is cancelled. Even at the positions of the seventh magnetic sensor unit 1000g to the tenth magnetic sensor unit 1000j, except for the sixth magnetic sensor unit 1000f, the influence of the magnetic field generated by the magnetic sensor unit 1000 on the other axis is canceled. . That is, for the first magnetic sensor unit 1000a to the tenth magnetic sensor unit 1000j provided in the magnetic detection device 1, the influence of the magnetic field from the other axis direction is reduced.

  Here, in the magnetic detection device 1 according to the present embodiment, if the influence of the magnetic field generated in the magnetic sensor unit 1000 of the other axis (different in the magnetic sensitive axis) is canceled, the position of the magnetic sensor unit 1000 is as shown in FIG. And may be different. In the example of FIG. 9, the fifth magnetic sensor unit 1000e and the sixth magnetic sensor unit 1000f whose magnetosensitive axis is the z direction are arranged side by side on one axis (for example, the z axis) parallel to the z axis direction. Is done. However, the fifth magnetic sensor unit 1000e and the sixth magnetic sensor unit 1000f may be at different positions in at least one of the x-axis direction and the y-axis direction. That is, the xy coordinates of the fifth magnetic sensor unit 1000e may be different from the xy coordinates of the sixth magnetic sensor unit 1000f.

[Third Embodiment]
10, FIG. 11 and FIG. 12 are diagrams showing a configuration example of the magnetic detection device 1 according to the third embodiment. The magnetic detection device 1 includes a plurality of magnetic sensor units 1000. In the present embodiment, the magnetic detection device 1 is configured by repeating the arrangement of the second embodiment. The configuration of the magnetic sensor unit 1000 included in the magnetic detection device 1 according to the present embodiment is the same as that of the first embodiment. In addition, the magnetic detection device 1 according to the present embodiment can be manufactured by a manufacturing method similar to the first embodiment. Therefore, description of the configuration of the magnetic sensor unit 1000 and the method for manufacturing the magnetic detection device 1 according to the present embodiment will be omitted.

  FIG. 10 is a cross-sectional view on the xy plane of the magnetic detection device 1 according to the present embodiment. FIG. 11 is a cross-sectional view in the zx plane of the magnetic detection device 1 according to the present embodiment. 10 and 11, the magnetic sensor unit 1000 is indicated by a rectangle. As described above, the magnetic detection device 1 according to this embodiment repeats the arrangement of the second embodiment. The first magnetic sensor unit 1000a to the tenth magnetic sensor unit 1000j in FIGS. 10 and 11 are the same as those in FIG.

  As shown in FIG. 10, the magnetic detection apparatus 1 according to the present embodiment includes a first magnetic sensor unit 1000a, a second magnetic sensor unit 1000b, a third magnetic sensor unit 1000c, and a fourth magnetic sensor unit 1000d. The arrangement (pattern Pxy in FIG. 10) is repeated in the x-axis direction and the y-axis direction on the xy plane. Here, the length of the pattern Pxy is the distance D in the x-axis direction and the y-axis direction, respectively. The distance D can take the same value as in the first embodiment. In the magnetic detection device 1 according to this embodiment, a plurality of magnetic sensor units 1000 are arranged while maintaining translational symmetry of the distance D in the x-axis direction and the y-axis direction. Here, the translational symmetry means that the same arrangement as before the translation is maintained when translated by a certain distance.

  As shown in FIG. 11, the magnetic detection apparatus 1 according to the present embodiment includes a first magnetic sensor unit 1000a, a second magnetic sensor unit 1000b, a fifth magnetic sensor unit 1000e, and a sixth magnetic sensor unit 1000f. The arrangement (pattern Pzx in FIG. 11) is repeated in the z-axis direction and the x-axis direction on the zx plane. Here, the length of the pattern Pzx is the distance D in the z-axis direction and the x-axis direction, respectively. In the magnetic detection device 1 according to this embodiment, a plurality of magnetic sensor units 1000 are arranged while maintaining translational symmetry of the distance D in the z-axis direction and the x-axis direction.

  FIG. 12 is a perspective view showing an example of a three-dimensional shape of the magnetic detection device 1 according to this embodiment. Although the repetition on a plane was demonstrated using FIG. 10 and FIG. 11, the magnetic detection apparatus 1 is the three-dimensional arrangement | positioning (one side is the distance D of the 1st magnetic sensor unit 1000a-the 6th magnetic sensor unit 1000f). (Cube shape) is arranged while maintaining translational symmetry. However, strictly speaking, translational symmetry may not be maintained at the end of the magnetic detection device 1. In this case, the magnetic detection device 1 can accurately detect the external magnetic field Bx by not using the detection value of the magnetic sensor unit 1000 at the end of the magnetic detection device 1. As described in the second embodiment, the influence of the magnetic field generated in the magnetic sensor unit 1000 on the other axis is the position of the magnetic sensor unit 1000 constituting the magnetic detection device 1 except for the case where it is arranged at the end. Canceled. By repeatedly arranging as in the present embodiment, it is possible to obtain the spatial distribution of the magnetic field from the measurement target while reducing crosstalk.

  Here, it is preferable that the magnetic detection apparatus 1 includes a signal processing circuit that calculates a difference between detection values of a plurality of magnetic sensor units 1000 having the same magnetosensitive axis direction. By calculating a difference between detection values, an environmental magnetic field component (for example, geomagnetism or the like) commonly included in a plurality of detection values is removed, and a signal magnetic field in the direction of the magnetic sensitive axis of the magnetic sensor unit 1000 is more accurately detected. Is possible.

  As described above, in the magnetic detection device 1, the three-dimensional arrangement of the first magnetic sensor unit 1000a to the sixth magnetic sensor unit 1000f is arranged while maintaining translational symmetry. Therefore, in the magnetic detection device 1, the magnetic sensor unit 1000 having the same direction of the magnetosensitive axis is located at a position away from one magnetic sensor unit 1000 by a predetermined distance (for example, distance D) in a predetermined direction (for example, the z direction). Is arranged. For example, the signal processing circuit has a predetermined distance in a predetermined direction for each of at least the first magnetic sensor unit 1000a, the second magnetic sensor unit 1000b, the third magnetic sensor unit 1000c, and the fourth magnetic sensor unit 1000d. The difference between the detected values is calculated between the magnetic sensor units 1000 that are arranged apart from each other. In the example of FIG. 9, the signal processing circuit may calculate a difference in detection value between the first magnetic sensor unit 1000a and the seventh magnetic sensor unit 1000g. Further, the signal processing circuit may calculate a difference between detection values between the third magnetic sensor unit 1000c and the ninth magnetic sensor unit 1000i. Further, the signal processing circuit may further calculate a difference in detection value between the fifth magnetic sensor unit 1000e and the sixth magnetic sensor unit 1000f. Here, the signal processing circuit may be a main processor that acquires a detection value from each magnetic sensor unit 1000 and controls the entire magnetic detection device 1. The predetermined direction may be the first direction, the second direction, or the third direction, but is not particularly limited. The predetermined distance may be the distance D, but is not particularly limited.

  The above embodiment exemplifies an apparatus and method for embodying the technical idea, and does not specify the material, shape, structure, arrangement, or the like of the component parts. That is, various modifications can be made within the technical scope defined by the claims described in the claims.

[Magnetic simulation]
Magnetic field analysis simulations by the finite element method were performed for the following examples and comparative examples. In the magnetic field analysis simulation, a magnetic body having an arbitrary shape and magnetic permeability and a conductor capable of flowing a current can be produced in a virtual space in the computer. When a magnetic material having a defined shape is divided into small regions of arbitrary size and a magnetic field is applied, the magnetization state of each small region in the magnetic material can be calculated. In the following, the winding axis direction of the canceling magnetic field generating unit 70 is the “length direction”, the direction perpendicular to the thickness of the magnetic body is “thickness direction”, and the direction perpendicular to the length direction and the thickness direction is “width direction”. It describes.

  In the virtual space, the winding axis direction is parallel to the magnetosensitive axis direction. First, components corresponding to one magnetic sensor unit 11 were defined on the virtual space. The magnetic body 210 corresponding to the magnetization free layer 21 of the magnetic sensor unit 11 was set to have a length direction of 100 μm, a width direction of 140 μm, a thickness direction of 0.07 μm, and a magnetic permeability of 2000. In addition, the magnetosensitive area 230 corresponding to the magnetization fixed layer 23 of the magnetic sensor unit 11 was set to 5 μm in the length direction and 28 μm in the width direction. The position of the magnetic sensitive area 230 is the central portion of the magnetic body 210 when viewed from above. Furthermore, the magnetic body 300 corresponding to the magnetic converging unit 30 of the magnetic sensor unit 11 was set to have a length direction of 5 mm, a width direction of 1 mm, a thickness direction of 10 μm, and a magnetic permeability of 2000. The gap between the magnetic body 210 and the magnetic body 300 in the direction of the magnetic sensitive axis was 5 μm, and the magnetic bodies 210 and 300 were arranged so that the centers of gravity coincided. The conductor 700 corresponding to the canceling magnetic field generating unit 70 is formed in a ring shape with a 0.2 mm diameter conductor element having a diameter of 6 mm, and is arranged such that 51 of them are arranged to be 10.2 mm in the length direction. It was.

In the following, “magnetic sensor” means a set defined as described above in magnetic simulation. In the magnetic simulation, when a current of 1 μA was applied to the conductor 700 of the magnetic sensor, the following value was obtained as the magnetization M ₀ of the magnetosensitive area 230.
M ₀ = 3.698 × 10 ⁻⁴ [T]

In each example and comparative example to be described later, a plurality of the magnetic sensors described above are arranged in a virtual space, and a current is applied to a conductor 700 included in another magnetic sensor adjacent to a certain magnetic sensor, thereby magnetizing the magnetic sensor. M _A was acquired (A represents each magnetic sensor). At this time, the ratio of M _{0 to} M _A corresponds to the mixed signal from the other axis. Therefore, it means that the smaller the value of M _A / M ₀ is, the smaller the influence of the other axis is. It will be shown below that the value of M _A / M ₀ in this example is higher than the value of M _A / M ₀ in the comparative example.

[Example 1]
Example 1 corresponds to the case where the distance D is 20 mm in FIG. In Example 1, the magnetic sensor X1 (corresponding to the first magnetic sensor unit 1000a) with the winding axis facing the x-axis direction is disposed at a position (−10 mm, 0) away from the origin in the virtual space. . In addition, the magnetic sensor X2 (corresponding to the second magnetic sensor unit 1000b) with the winding axis facing the x-axis direction was disposed at a position (10 mm, 0) away from the origin in the virtual space. In addition, the magnetic sensor Y1 (corresponding to the third magnetic sensor unit 1000c) with the winding axis facing the y-axis direction was arranged at a position (0, −10 mm) away from the origin in the virtual space. Further, the magnetic sensor Y2 (corresponding to the fourth magnetic sensor unit 1000d) with the winding axis facing the y-axis direction was disposed at a position (0, 10 mm) away from the origin in the virtual space.

Next, when the values of the Y direction magnetization component M _Y1 and the Y direction magnetization component M _Y2 of the magnetic sensor Y1 are obtained in a state where a current of 1 μA is applied to the magnetic sensor X1 and the magnetic sensor X2, the following values are obtained. Obtained.
M _Y1 = −1.473 × 10 ⁻⁸ [T]
M _Y2 = 1.464 × 10 ⁻⁸ [T]

When the values of magnetization M _Y1 / M _O and M _Y2 / M _O were calculated, the following values were obtained.
M _Y1 / M _O = −0.0040 [%]
M _Y2 / M _O = 0.0040 [%]

[Example 2]
Example 2 corresponds to the case where the distance D is 20 mm in FIG. Here, as in the first embodiment, the distance D is a distance between adjacent magnetic sensor units 1000 in each axial direction. In the second embodiment, adjacent magnetic sensor units 1000 arranged side by side in the z-axis direction are separated by a distance D in the z-axis direction. In the example of FIG. 9, the center of gravity Ge and the center of gravity Gf are separated by a distance D. In Example 2, the magnetic sensor X1 (corresponding to the first magnetic sensor unit 1000a) whose winding axis is in the x-axis direction is located at a position (−10 mm, 0, 20 mm) away from the origin in the virtual space. Arranged. In addition, the magnetic sensor X2 (corresponding to the second magnetic sensor unit 1000b) with the winding axis facing the x-axis direction was disposed at a position (10 mm, 0, 20 mm) away from the origin in the virtual space. Further, the magnetic sensor Y1 (corresponding to the third magnetic sensor unit 1000c) with the winding axis facing the y-axis direction was disposed at a position (0, −10 mm, 20 mm) away from the origin in the virtual space. In addition, the magnetic sensor Y2 (corresponding to the fourth magnetic sensor unit 1000d) with the winding axis facing the y-axis direction was disposed at a position (0, 10 mm, 20 mm) away from the origin in the virtual space. In addition, the magnetic sensor Z1 (corresponding to the fifth magnetic sensor unit 1000e) with the winding axis facing the z-axis direction was arranged at a position (0, 0, 30 mm) away from the origin in the virtual space. In addition, the magnetic sensor Z2 (corresponding to the sixth magnetic sensor unit 1000f) with the winding axis facing the z-axis direction was arranged at a position (0, 0, 10 mm) away from the origin in the virtual space. Further, the magnetic sensor X3 (corresponding to the seventh magnetic sensor unit 1000g) with the winding axis facing the x-axis direction was arranged at a position (−10 mm, 0, 0) away from the origin in the virtual space. Further, the magnetic sensor X4 (corresponding to the eighth magnetic sensor unit 1000h) with the winding axis facing the x-axis direction was arranged at a position (10 mm, 0, 0) away from the origin in the virtual space. In addition, the magnetic sensor Y3 (corresponding to the ninth magnetic sensor unit 1000i) with the winding axis in the y-axis direction was disposed at a position (0, −10 mm, 0) away from the origin in the virtual space. In addition, the magnetic sensor Y4 (corresponding to the tenth magnetic sensor unit 1000j) with the winding axis facing the y-axis direction was disposed at a position (0, 10 mm, 0) away from the origin in the virtual space.

Next, with the current of 1 μA applied to the magnetic sensors X1 to X4, the values of the Y direction magnetization components M _{Y1 to} M _Y4 of the magnetic sensors Y1 to _Y4 and the Z direction magnetization components M _Z1 and M _Z2 of _Z1 and _Z2 are set. As a result, the following values were obtained.
M _Y1 = 1.448 × 10 ⁻⁸ [T]
M _Y2 = −1.455 × 10 ⁻⁸ [T]
M _Y3 = 1.449 × 10 ⁻⁸ [T]
M _Y4 = −1.456 × 10 ⁻⁸ [T]
M _Z1 = −4.175 × 10 ⁻¹⁰ [T]
M _Z2 = −5.283 × 10 ⁻¹² [T]

Further, when the values of the magnetizations M _Y1 to _Y4 / M _O , M _Z1 and _Z2 / M _O were calculated, the following values were obtained.
M _Y1 / M _O = 0.0039%
M _Y2 / M _O = −0.0039%
M _Y3 / M _O = 0.0039%
M _Y4 / M _O = −0.0039%
M _Z1 / M _O = −0.00011%
M _Z2 / M _O = −0.0000014%

[Comparative Example 1]
Comparative Example 1 corresponds to the case where the distance D is 20 mm in FIG. 7 and the first magnetic sensor unit 1000a and the third magnetic sensor unit 1000c are deleted. In Comparative Example 1, the magnetic sensor X2 with the winding axis facing the x-axis direction was arranged at a position (10 mm, 0) away from the origin in the virtual space. Further, the magnetic sensor Y2 with the winding axis facing the y-axis direction was arranged at a position (0, 10 mm) away from the origin in the virtual space.

Next, when the value of the Y-direction magnetization component M _Y2 of the magnetic sensor Y2 was obtained in a state where a current of 1 μA was applied to the magnetic sensor X2, the following value was obtained.
M _Y2 = −8.075 × 10 ⁻⁶ [T]

When the value of magnetization M _Y2 / M _O was calculated, the following value was obtained.
M _Y2 / M _O = -2.18 [%]

[Comparison of simulation results]
In the examples and comparative examples of magnetic simulation, when the winding shaft is driven sensor in the X direction, the sensor winding axis is oriented in the Y direction and the Z direction, and compared the ratio of M _O for M _A. That is, crosstalk from other axes was evaluated by comparing the magnetic susceptibility in a direction different from the winding axis of the conductor 700. The smaller M _A / M _O means that the crosstalk is smaller. From the results of Examples and Comparative Examples, it can be seen that M _A / M _O Example respect clearly Comparative Example is smaller. This effect is obtained because the magnetic fields generated from the magnetic sensor units cancel each other's axial components when arranged as in the embodiment.

  From the above, it can be seen that the above embodiment exhibits an effect of reducing crosstalk of signals from the magnetic sensors on the other axes than the comparative example.

[Another embodiment]
In the magnetic detection device 1 according to the above embodiment, a plurality of magnetic sensor units 1000 are repeatedly arranged for each distance D in the x-axis direction and the y-axis direction. In other words, in the above embodiment, they are repeatedly arranged with translational symmetry. Here, as another embodiment, the translational symmetry may not be satisfied in at least a part of the configuration in which the magnetic sensor units 1000 are arranged in an array. For a portion where the translational symmetry is not satisfied, for example, in a plane including two directions, the plurality of magnetic sensor units 1000 satisfy the following arrangement condition. For example, the first magnetic sensor unit 1000a, the second magnetic sensor unit 1000b, and the third magnetic sensor unit 1000c in a plane (xy plane) including the x-axis direction and the y-axis direction of the portion where the translational symmetry is not satisfied. And a fourth magnetic sensor unit 1000d. At this time, the first magnetic sensor unit 1000a and the second magnetic sensor unit 1000b are arranged side by side in the first direction so that the direction of the magnetosensitive axis is the first direction (x-axis direction). . Further, the third magnetic sensor unit 1000c and the fourth magnetic sensor unit 1000d have the second direction so that the direction of the magnetosensitive axis is the second direction (y-axis direction) substantially orthogonal to the first direction. Arranged side by side. The first magnetic sensor unit 1000a and the second magnetic sensor unit 1000b include a plane including the center of gravity of the third magnetic sensor unit 1000c and having the second direction as a normal direction, and the fourth magnetic sensor unit 1000d. And a plane including the center of gravity and having the second direction as a normal direction. The third magnetic sensor unit 1000c and the fourth magnetic sensor unit 1000d include a plane including the center of gravity of the first magnetic sensor unit 1000a and having the first direction as the normal direction, and the second magnetic sensor unit. And a plane including the center of gravity of 1000b and having the first direction as the normal direction. The arrangement conditions are the same for another plane (for example, the zx plane).

  In other words, even if there is a deviation between a pair of magnetic sensor units 1000 having the same direction of the magnetic sensitive axis, the magnetic sensor unit 1000 having a magnetic sensitive axis in a different direction is generated as long as the above arrangement condition is satisfied. A part of the magnetic field component (magnetic field component generated from the other axis) is canceled. Therefore, the magnetic detection apparatus 1 can improve the detection accuracy. Thus, the magnetic sensor units 1000 do not necessarily have to be regularly arranged as shown in FIGS. For example, “the magnetic sensor unit 1000 is arranged side by side in the first direction so that the direction of the magnetic sensitive axis is the first direction” means that the magnetic sensitive axis of the magnetic sensor unit 1000 is arranged on the same straight line. There is no need, and an arrangement in which the magnetic sensitive axes of the magnetic sensor unit 1000 are parallel to each other is included.

  FIG. 13 shows an example satisfying the above-described arrangement condition regarding the xy plane. As shown in FIG. 13, the first magnetic sensor unit 1000a and the second magnetic sensor unit 1000b have an axis (y that connects the center of gravity of the third magnetic sensor unit 1000c and the center of gravity of the fourth magnetic sensor unit 1000d. It is not symmetrical with respect to the axis parallel to the axis. That is, the first magnetic sensor unit 1000a and the second magnetic sensor unit 1000b are displaced in the y-axis direction. The repeated arrangement of FIG. 13 is the same arrangement as (0, 0), for example, at a position moved by (2D, 0) or (0, 2D) from the position of coordinates (0, 0). However, the repeated arrangement of FIG. 13 is not the same arrangement as the position (0, 0) at a position moved (D, 0) or (0, D) from the position of the coordinates (0, 0), for example. Even in this case, it is possible to obtain the spatial distribution of the magnetic field from the measurement object while reducing the crosstalk.

  FIG. 14 shows another example that satisfies the arrangement condition regarding the xy plane. In the example of FIG. 14, not only the first magnetic sensor unit 1000a and the second magnetic sensor unit 1000b but also the third magnetic sensor unit 1000c and the fourth magnetic sensor unit 1000d are shifted. Even in this case, it is possible to obtain the spatial distribution of the magnetic field from the measurement object while reducing the crosstalk.

  FIG. 15 shows an example in which a fifth magnetic sensor unit 1000e and a sixth magnetic sensor unit 1000f having a shift in the z-axis direction are arranged in addition to the four magnetic sensor units 1000 of FIG. In the example of FIG. 15, the center of gravity of the fifth magnetic sensor unit 1000e includes the center of gravity of the first magnetic sensor unit 1000a, the plane 1 having the first direction (x-axis direction) as the normal direction, and the second Including the center of gravity of the magnetic sensor unit 1000b and the plane 2 having the first direction as the normal direction, and including the center of gravity of the third magnetic sensor unit 1000c in the second direction (y (Axial direction) is disposed between the plane 3 having the normal direction and the plane 4 including the center of gravity of the fourth magnetic sensor unit 1000d and having the second direction as the normal direction. The center of gravity of the sixth magnetic sensor unit 1000f includes the center of gravity of the first magnetic sensor unit 1000a, the plane 1 having the first direction as the normal direction, and the center of gravity of the second magnetic sensor unit 1000b. The plane 3 that is disposed between the plane 2 having the first direction as the normal direction and includes the center of gravity of the third magnetic sensor unit 1000c and having the second direction as the normal direction; 4 between the planes 4 including the center of gravity of the four magnetic sensor units 1000d and having the second direction as the normal direction. The first magnetic sensor unit 1000a, the second magnetic sensor unit 1000b, the third magnetic sensor unit 1000c, and the fourth magnetic sensor unit 1000d include the center of gravity of the fifth magnetic sensor unit 1000e, Between the plane 5 having the direction (z-axis direction) as the normal direction and the plane 6 including the center of gravity of the sixth magnetic sensor unit 1000f and having the third direction as the normal direction. As described above, the example of FIG. 15 satisfies the arrangement condition regarding the zx plane and the yz plane in addition to the arrangement condition regarding the xy plane. At this time, it is possible to obtain the spatial distribution of the magnetic field from the measurement target while reducing the crosstalk.

  As still another embodiment, the magnetic sensor unit 1000 may omit some of the components provided in the above embodiment. As an example, the magnetic sensor unit 1000 may omit the cancel magnetic field generation unit 70 and an electric circuit that generates a cancel current. Further, the magnetic sensor unit 1000 may omit the magnetic convergence unit 30. Even when some of the components included in the magnetic sensor unit 1000 in the above embodiment are omitted, the influence of the magnetic field from the other axis direction is reduced as long as the above arrangement condition is satisfied among the magnetic sensor units 1000. Is done. Therefore, the magnetic detection apparatus 1 can improve the detection accuracy. Here, when the magnetic sensor unit does not include a cancel magnetic field generation unit, the center of gravity of the magnetically sensitive area of the magnetic sensor unit is “the center of gravity of the magnetic sensor unit”. When the magnetic sensor unit has a plurality of magnetic sensing areas, the center of gravity of the magnetic sensor unit is the total center of gravity of the plurality of magnetic sensing areas.

DESCRIPTION OF SYMBOLS 1 Magnetic detection apparatus 10 Board | substrate 11 Magnetic sensor part 20 Element part 21 Magnetization free layer 22 Magnetic layer 23 Magnetization fixed layer 30 Magnetic convergence part 31 Seed layer 40 Protective layer 40a Energizing window 41 Protective layer 50 Element wiring part 70 Canceling magnetic field generation part 81 Resistor 82 Resistor 83 Resistor 90 Current detector 100 Main component 210 Magnetic body 230 Magnetic sensing area 300 Magnetic body 700 Conductor 1000 Magnetic sensor unit

Claims (16)

A magnetic sensor unit including a magnetic sensor unit including a substrate and an element unit, a cancel magnetic field generation unit, and an electric circuit, wherein at least a part of the magnetic sensor unit exists inside an envelope surface of the cancel magnetic field generation unit A plurality of
The element unit outputs a detection value corresponding to an input magnetic field component in the direction of the magnetosensitive axis,
The cancel magnetic field generation unit is formed by winding a conductor with a winding axis in a direction substantially parallel to the magnetosensitive axis,
The electrical circuit applies a feedback current based on the detection value to the cancel magnetic field generation unit, thereby causing the cancel magnetic field generation unit to generate a cancel magnetic field that attenuates the input magnetic field,
The plurality of magnetic sensor units include at least a first magnetic sensor unit, a second magnetic sensor unit, a third magnetic sensor unit, and a fourth magnetic sensor unit,
The first magnetic sensor unit and the second magnetic sensor unit are arranged side by side in the first direction so that the direction of the magnetosensitive axis is the first direction,
The third magnetic sensor unit and the fourth magnetic sensor unit are aligned in the second direction so that the direction of the magnetosensitive axis is a second direction substantially orthogonal to the first direction. Arranged,
The first magnetic sensor unit and the second magnetic sensor unit include a plane that includes the center of gravity of the third magnetic sensor unit and has the second direction as a normal direction, and the fourth magnetic sensor unit. And a plane having a normal direction in the second direction,
The third magnetic sensor unit and the fourth magnetic sensor unit include a plane that includes the center of gravity of the first magnetic sensor unit and that has the first direction as a normal direction, and the second magnetic sensor unit. And a plane that includes the center of gravity and has the first direction as the normal direction. The plurality of magnetic sensor units are arranged such that a direction of the magnetosensitive axis is a third direction substantially orthogonal to the first direction and the second direction. Including
The center of gravity of the fifth magnetic sensor unit includes the center of gravity of the first magnetic sensor unit, includes a plane having the first direction as a normal direction, and the center of gravity of the second magnetic sensor unit, A plane that is disposed between a plane that has a first direction as a normal direction and that includes a center of gravity of the third magnetic sensor unit and that has a second direction as a normal direction, and the fourth direction. The magnetic detection device according to claim 1, wherein the magnetic detection device is arranged between a plane including the center of gravity of the magnetic sensor unit and having the second direction as a normal direction. The plurality of magnetic sensor units include a sixth magnetic sensor unit, which is arranged so that the direction of the magnetosensitive axis is the third direction,
The center of gravity of the sixth magnetic sensor unit includes the center of gravity of the first magnetic sensor unit, includes a plane having the first direction as a normal direction, and the center of gravity of the second magnetic sensor unit, A plane that is disposed between a plane that has a first direction as a normal direction and that includes a center of gravity of the third magnetic sensor unit and that has a second direction as a normal direction, and the fourth direction. A plane including the center of gravity of the magnetic sensor unit and having the second direction as a normal direction,
The first magnetic sensor unit, the second magnetic sensor unit, the third magnetic sensor unit, and the fourth magnetic sensor unit include the center of gravity of the fifth magnetic sensor unit, and the third direction The magnetic detection according to claim 2, wherein the magnetic detection unit is disposed between a plane having a normal direction and a plane including the center of gravity of the sixth magnetic sensor unit and having the third direction as a normal direction. apparatus.   4. The magnetic detection device according to claim 1, further comprising a signal processing circuit that calculates a difference between the detection values of the plurality of magnetic sensor units having the same direction of the magnetosensitive axis. 5.   The signal processing circuit is disposed at a predetermined distance away in a predetermined direction for each of at least the first magnetic sensor unit, the second magnetic sensor unit, the third magnetic sensor unit, and the fourth magnetic sensor unit. The magnetic detection device according to claim 4, wherein a difference between the detection values is calculated between the different magnetic sensor units. Said first magnetic sensor unit, the second magnetic sensor units, the arrangement of the third magnetic sensor unit and the fourth magnetic sensor unit is repeated before Symbol first direction and said second direction The magnetic detection device according to any one of claims 1 to 5.   The magnetic detection device according to claim 6, wherein the electric circuit has a function of adjusting an offset value of the feedback current.   The said magnetic sensor part is a magnetic detection apparatus as described in any one of Claim 1 to 7 containing the magnetic convergence part which converges an input magnetic field on the said element part. The magnetic convergence part is
Arranged on both sides of the element portion in a direction parallel to the magnetosensitive axis,
A first length that is a length connecting both ends in the direction of the magnetosensitive axis, a second length that is a maximum length in a direction perpendicular to the main surface of the substrate, the direction of the magnetosensitive axis, and the A third length, which is a length connecting both ends in a direction perpendicular to a direction perpendicular to the main surface of the substrate, and the second length <the third length <the first length. The magnetic detection device according to claim 8, wherein the magnetic detection device is satisfied. The magnetic converging portion includes a first soft magnetic body formed on the substrate,
The magnetic detection apparatus according to claim 8, further comprising a second soft magnetic body that is in direct contact with the first soft magnetic body.   The said magnetic sensor unit is a magnetic detection apparatus as described in any one of Claims 8-10 provided with the said magnetic converging part inside the envelope surface of the said cancellation magnetic field generation | occurrence | production part.   12. The magnetic detection device according to claim 1, wherein the element unit includes a magnetization free layer, a nonmagnetic layer, and a magnetization fixed layer. In the element portion, the magnetization free layer, the nonmagnetic layer, and the magnetization fixed layer are laminated in this order,
The magnetic detection device according to claim 12, wherein an area of a surface of the magnetization free layer parallel to the main surface of the substrate is larger than an area of a surface of the magnetization fixed layer parallel to the main surface of the substrate. The magnetic sensor unit includes a plurality of the element units,
The plurality of element parts are arranged so as to be aligned in a direction perpendicular to the direction of the magnetic sensitive axis of the magnetic sensor part, and are electrically connected in series. Magnetic detection device.   The thickness of the said magnetization free layer, the thickness of a said 1st soft magnetic body, and the thickness of a said 2nd soft magnetic body become large in this order, The magnetism as described in any one of Claims 12-14. Detection device.   The length in the direction of the magnetic sensitive axis of the magnetization free layer is larger than the length of the region sandwiched between the magnetic converging portions arranged on both sides of the element portion, according to any one of claims 12 to 15. The magnetic detection apparatus as described.

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