JP6222897B2 - Multi-axis magnetic sensor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a multi-axis magnetic sensor including a magnetoresistive effect element formed on a single substrate and capable of detecting a magnetic field component having at least two axes, and a method for manufacturing the same.

  In applications that detect magnetic field components in three-axis directions, such as detection of geomagnetism, three magnetic sensors such as a Hall element, a magnetoresistive element, and a magneto-impedance element can be detected in three axes. A method of forming an electronic compass capable of detecting three axes by assembling a single package with the respective magnetosensitive directions directed in the directions (x, y, z axes) is known (Patent Document 1). .

  In Patent Document 2, an inclined portion is provided on a substrate on which a sensor is formed, and a magnetoresistive effect element is formed on the inclined surface, whereby a horizontal direction (x and y axes) and a vertical direction (z A method for producing a sensor for detecting a magnetic field on the axis) is disclosed.

Japanese Patent No. 4495240 JP 2007-212275 A

  However, the method as described in Patent Document 1 has a problem that the cost is high because a special assembly technique is required in addition to the cost of the sensor chip itself.

  Moreover, in the method in Patent Document 2, in order to produce a sensor that detects a biaxial magnetic field in the horizontal direction, an array of permanent magnets combining N poles and S poles is used in each sensor chip. Processing to fix the magnetization of the pinned layer in four different directions (± x axis, ± y axis) is performed. In order to detect the z-axis magnetic field, an inclined portion is provided on the substrate, and a magnetoresistive element is formed thereon. Such processing for each chip and a special process have a problem that the manufacturing process is complicated and the cost is increased.

  Therefore, an object of the present invention is to provide a triaxial magnetic sensor including a magnetoresistive effect element capable of detecting a triaxial magnetic field component by a simple process, and a manufacturing method thereof.

The multi-axis magnetic sensor capable of detecting a triaxial magnetic field according to claim 1, wherein the pinned layer has magnetization fixed in a first direction, and the direction of magnetization is the first direction. A plurality of magnetoresistive elements having a free layer that can be changed in a second direction different from the above, and a predetermined region that spatially covers a position where at least one of the plurality of magnetoresistive elements is disposed A plurality of magnetoresistive elements arranged in the area of the magnetic converging means in plan view under the magnetic converging means, and the magnetization of the pinned layer in each magnetoresistive element The direction is fixed in the first direction .

  In the invention according to claim 2, the free layer is characterized in that an easy axis of magnetization is induced in a second direction orthogonal to the first direction or magnetization is induced in a second direction.

  The invention according to claim 3 is characterized in that the magnetic converging means is a magnetic converging body that changes the direction and magnitude of a magnetic field in a predetermined region with respect to an external magnetic field.

  According to a fourth aspect of the present invention, the magnetoresistive effect element is configured as a single resistor, and by driving the single resistor with a constant current source, a difference in voltage between terminals obtained from at least two single resistors is obtained. It is characterized by outputting.

  According to a fifth aspect of the present invention, the magnetoresistive effect element is configured as a Wheatstone bridge, and the Wheatstone bridge is driven by a constant current source.

  The invention according to claim 6 further includes a substrate containing Si on which an LSI is formed, wherein the LSI and the magnetoresistive element are electrically connected.

  The invention according to claim 7 is characterized in that the magnetoresistive effect element comprises a TMR element.

  The invention according to claim 8 is characterized in that the magnetoresistive effect element comprises a GMR element.

  The invention according to claim 9 is characterized in that the magnetization of the free layer is induced by a bias magnet disposed in the vicinity of the magnetoresistive element.

  The invention according to claim 10 is characterized in that the magnetization of the free layer is induced by a magnetic field generated by a current flowing through an electric wiring disposed in the vicinity of the magnetoresistive effect element.

  The invention according to claim 11 is characterized in that the easy axis of magnetization of the free layer is induced by shape anisotropy.

  The invention according to claim 12 is characterized in that a triaxial magnetic field can be detected using a plurality of magnetoresistive elements.

14. The method of manufacturing a multi-axis magnetic sensor capable of detecting a triaxial magnetic field according to claim 13, wherein the pinned layer has magnetization fixed in a first direction on a plane of one substrate. And a free layer capable of changing the direction of magnetization to a second direction different from the first direction via an intermediate layer on the pinned layer whose magnetization is fixed in the first direction. And forming a plurality of magnetoresistive elements, and magnetic converging means is disposed in a predetermined region that spatially covers a position where at least one of the plurality of magnetoresistive elements is disposed. comprising the steps, in the step of creating a plurality of magnetoresistive elements, the plurality of magnetoresistive elements, the bottom of the magnetic flux concentrator means is arranged in the region of the magnetic flux concentrator means in a plan view, each magnetoresistive element Direction of magnetization of the pinned layer at Is fixed in the first direction .

  According to the present invention, a plurality of magnetoresistances having a pinned layer whose magnetization is fixed in a first direction and a free layer capable of changing the magnetization direction to a second direction different from the first direction. And a magnetic focusing means disposed in a predetermined region that spatially covers a position where at least one of the plurality of magnetoresistive elements is arranged, so that the magnetization direction of the pinned layer is changed in the manufacturing process. A multi-axis magnetic sensor can be fabricated using magnetoresistive elements in only one direction, whereby a plurality of pinned layer magnetizations are fixed in a plurality of directions on a substrate constituting the multi-axis magnetic sensor. It is not necessary to provide a magnetoresistive effect element, and a multiaxial magnetic sensor comprising a magnetoresistive effect element capable of detecting a multiaxial magnetic field component using a simple manufacturing process can be obtained.

It is explanatory drawing which shows the basic composition of the magnetoresistive effect element which is the 1st Embodiment of this invention. The structure of a magnetoresistive effect element is shown, (a) is explanatory drawing when a magnetization easy axis is induced | guided | derived to the direction orthogonal to the magnetization direction of a pinned layer, (b) is magnetized in the direction orthogonal to the magnetization direction of a pinned layer. It is explanatory drawing when is induced. It is explanatory drawing which shows the dependence with respect to the magnetic field of the resistance value of a magnetoresistive effect element. It is explanatory drawing which shows the shape of a magnetic convergence board. It is explanatory drawing which shows distribution of the magnetic field below 5 micrometers from the bottom face of a magnetic concentrating plate, and shows the magnetic field generated in the X-axis direction when the external magnetic field 1Oe is applied in the X-axis direction. It is explanatory drawing which shows the distribution of the magnetic field below 5 micrometers from the bottom face of a magnetic concentrating plate, and shows the magnetic field generated in the X-axis direction when the external magnetic field 1Oe is applied in the Y-axis direction. It is explanatory drawing which shows distribution of the magnetic field below 5 micrometers from the bottom face of a magnetic converging plate, and shows the magnetic field generated in the X-axis direction when the external magnetic field 1Oe is applied in the Z-axis direction. It is explanatory drawing which shows the typical point showing the positional relationship with respect to the magnetic convergence board of FIG. It is explanatory drawing which shows the coordinate value of the point of FIG. 8, and the magnitude | size of a magnetic field. It is explanatory drawing which shows the structure of the magnetic sensor at the time of using the magnetoresistive effect element as a single resistor which is the 2nd Embodiment of this invention. It is explanatory drawing which shows the structure of the Wheatstone bridge type | mold magnetic sensor which combined the magnetoresistive effect element which is the 3rd Embodiment of this invention. It is a top view which shows the structural example of the triaxial magnetic sensor which can detect the magnetic field of a triaxial direction which is the 4th Embodiment of this invention. It is a top view which shows the structural example of the triaxial magnetic sensor which can detect the magnetic field of the triaxial direction which is the 5th Embodiment of this invention. It is sectional drawing which shows the structural example of the triaxial magnetic sensor which can detect the magnetic field of the triaxial direction which is the 5th Embodiment of this invention. It shows that the magnetization of the free layer is induced in the direction perpendicular to the magnetization of the pinned layer by the bias magnet formed in the vicinity of the free layer of the magnetoresistive effect element according to the sixth embodiment of the present invention. It is explanatory drawing. It shows that the magnetization of the free layer is induced in the direction orthogonal to the magnetization of the pinned layer by the electrical wiring formed in the vicinity of the free layer of the magnetoresistive effect element, which is the seventh embodiment of the present invention It is explanatory drawing. It is explanatory drawing which shows the other structural example of the electrical wiring formed in the vicinity of the free layer of a magnetoresistive effect element. 8 shows a configuration in which the easy axis of magnetization of the free layer is induced in the direction orthogonal to the magnetization of the pinned layer by the shape anisotropy according to the eighth embodiment of the present invention, and FIG. It is explanatory drawing which shows the state by which the magnetic pole was induced | guided | derived to the cross section perpendicular | vertical to a major axis direction by applying a magnetic field to the major axis direction of the magnetoresistive effect element which has, (b) is magnetoresistive which has shape anisotropy It is explanatory drawing which shows the state by which the magnetic pole was induced | guided | derived to the cross section perpendicular | vertical to a short-axis direction by applying a magnetic field to the short-axis direction of an effect element. It is explanatory drawing which shows the structure of the magnetoresistive effect element by which the easy axis of magnetization was induced | guided | derived to the direction orthogonal to the magnetization direction of a pinned layer. 9 shows a configuration of the ninth embodiment of the present invention viewed from a direction perpendicular to the magnetosensitive surface of a magnetoresistive element, (a) is a plan view showing a rectangle, and (b) is a meander-shaped magnetoresistive element. It is explanatory drawing which shows an effect element.

[First example]
A first embodiment of the present invention will be described with reference to FIGS.

<Overview>
First, a schematic configuration of the multi-axis magnetic sensor will be described.

  In this example, a plurality of magnetoresistive effect elements 1 shown in FIGS. 1 to 3 and a magnetic convergence means shown in FIGS. 4 to 9, which constitute a multi-axis magnetic sensor capable of detecting a magnetic field of two or more axes. 10 will be described.

  Each magnetoresistive effect element 1 can change the magnetization direction to a direction different from the first direction X including the second direction Y, and the pinned layer 2 in which the magnetization is fixed in the first direction X. And a free layer 4. The free layer 4 may be configured such that the easy axis is induced in the second direction Y orthogonal to the first direction X, or the magnetization is induced in the second direction.

  The magnetic converging means 10 is disposed in a region that spatially covers a position where at least one of the plurality of magnetoresistive effect elements 1 is disposed. The magnetic focusing means 10 is made of a magnetic material. This magnetic body may be configured as a magnetic converging body in which the direction and magnitude of the magnetic field in a predetermined region change as the magnetization of the magnetic body changes due to an external magnetic field.

  Hereinafter, a specific example will be described.

<Specific example>
FIG. 1 shows a basic configuration of the magnetoresistive effect element 1.

  The magnetoresistive effect element 1 mainly includes a pinned layer 2, an intermediate layer 3, and a free layer 4. The resistance value in the horizontal direction to the film surface or in the vertical direction to the film surface varies depending on the relative magnetization angle between the pinned layer 2 in which the magnetization is fixed and the free layer 4 in which the magnetization direction can be changed. Has characteristics.

  In the case where the magnetoresistive effect element 1 is a GMR (Giant Magnetic Resistance) element, the intermediate layer 3 is made of a conductive layer such as Cu.

When the magnetoresistive effect element 1 is a TMR (Tunnel Magneto Resistance) element, the intermediate layer 3 is composed of an insulating layer such as Al ₂ O ₃ or MgO. After the formation of the magnetoresistive film, the magnetization of the pinned layer is fixed in the direction of the magnetic field by performing a heat treatment (annealing process) in a magnetic field.

  FIG. 2 shows a configuration example of the single magnetoresistive element 1.

  FIG. 2A shows a state where the easy axis of the free layer 4 is induced in a direction orthogonal to the magnetization direction of the pinned layer 2. FIG. 2B shows a state in which the magnetization of the free layer 4 is induced in a direction orthogonal to the magnetization direction of the pinned layer 2. In this first example, the magnetoresistive element 1 has a rectangular shape of 1 μm in the X-axis direction and 10 μm in the Y-axis direction.

  FIG. 3 shows the dependence of the resistance of the magnetoresistive element 1 on the magnetic field.

  The magnetic field is applied in the magnetization direction of the pinned layer 2 so that the magnetization direction of the pinned layer 2 is positive. In the state of no magnetic field, the magnetizations of the pinned layer 2 and the free layer 4 are orthogonal. When a weak magnetic field is applied in the positive direction, the magnetization of the free layer 4 moves in a direction that aligns with the direction of the pinned layer 4, so that the resistance value decreases and becomes saturated at a magnetic field above a certain level. On the other hand, when a weak magnetic field is applied in the negative direction, the magnetization of the free layer 4 moves in the direction opposite to the direction of the pinned layer 2, so that the resistance value increases and saturation is observed at a magnetic field above a certain level. When a stronger magnetic field is applied, the magnetization of the pinned layer that has been fixed starts to turn negative, and the resistance value decreases. Therefore, by taking the direction of the pinned layer 2 as the sensitivity axis, it is possible to obtain a linearly changing characteristic with respect to an external magnetic field smaller than the constant positive and negative magnetic fields.

<Magnetic convergence plate>
4 to 7 show the shape of the magnetic converging plate 10 and the magnetic field distribution 5 um below (z-axis direction) from the bottom surface of the magnetic converging plate 10.

  FIG. 4 is a schematic diagram of the magnetic convergence plate 10.

  FIG. 5 shows a magnetic field distribution in the X direction when a magnetic field of 1 Oe is applied in the X direction (unit: Oe).

  FIG. 6 shows a magnetic field distribution in the X direction when a magnetic field of 1 Oe is applied in the Y direction (unit: Oe).

  FIG. 7 shows a magnetic field distribution in the X direction when a magnetic field of 1 Oe is applied in the Z direction (unit: Oe).

  The direction and magnitude of the magnetic field applied from the outside change depending on the magnetization of the magnetic flux converging plate 10. Even when a magnetic field is applied not only in the X-axis direction (FIG. 5), but also in the Y-axis (FIG. 6) or Z-axis direction (FIG. 7), the ratio of the magnetic field component in the X-axis direction depends on the shape. Occurs.

  Therefore, by arranging the magnetoresistive effect element 1 having the sensitivity axis in the X-axis direction under the magnetic converging plate 10, the magnetoresistive effect element 1 having sensitivity in all three axis directions can be made.

  In addition, since the role of the magnetic converging plate 10 is to generate a magnetic field in the sensitivity axis direction of the magnetoresistive effect element 1 by distorting the external magnetic field, the shape is not limited to a rectangular parallelepiped as in this example. For example, a cylinder, an elliptical cylinder, or a combination of a plurality of magnetic converging plates can be used as long as the object is achieved. As a material for the magnetic flux concentrating plate, a soft magnetic material having a small coercive force and a high magnetic permeability is preferably used, and permalloy (NiFe) is preferably used.

  FIG. 8 shows representative points in FIGS.

  FIG. 9 shows the magnitude of the magnetic field in the X-axis direction at each point ((1) to (10)) in the region 11.

  Here, the coordinate values (X, Y) and (unit: um) of each point ((1) to (10)) in FIG. 8 are shown (unit: Oe). In any point, the Z coordinate is -5 (5 um below the bottom surface of the magnetic focusing plate).

  As an example, at the position of the point (1) in the region 11, when an external magnetic field of 1 Oe is applied in the X-axis direction, a 1.07 Oe magnetic field in the X-axis direction is generated, and the external magnetic field 1 Oe is applied in the Y-axis direction. When applied, a magnetic field in the X-axis direction of −0.08 Oe is generated, and when an external magnetic field 1 Oe is applied in the Z-axis direction, a magnetic field in the X-axis direction of 0.02 Oe is generated.

  The shape of the magnetic converging plate 10 that is a magnetic body as the magnetic converging means may be a substantially line-symmetric shape with respect to the first direction X and the second direction Y. The plurality of magnetoresistive effect elements 1 may include two at positions symmetrical with respect to the first direction X and two at positions symmetrical with respect to the second direction Y.

  As described above, the pinned layer 2 whose magnetization is fixed in the first direction X, and the second direction in which the magnetization direction is different from the first direction X (in this example, orthogonal to the first direction X) A plurality of magnetoresistive effect elements 1 having a free layer that can be changed in the second direction) and a position in which at least one of the plurality of magnetoresistive effect elements 1 is spatially covered. Therefore, the multi-axis magnetic sensor can be manufactured by using the magnetoresistive effect element 1 in which the pinned layer has only one magnetization direction in the manufacturing process. As a result, it is not necessary to provide an inclined portion for arranging a plurality of magnetoresistive effect elements 1 in which the magnetization of the pinned layer is fixed in a plurality of directions on the substrate constituting the multi-axis magnetic sensor as in the prior art. Thus, a multi-axis magnetic sensor composed of the magnetoresistive effect element 1 capable of detecting multi-axis magnetic field components using a simple manufacturing process can be obtained.

[Second example]
A second embodiment of the present invention will be described with reference to FIG. In addition, about the same part as the 1st example mentioned above, the description is abbreviate | omitted and the same code | symbol is attached | subjected.

  In this example, the magnetoresistive effect element 1 is configured as single resistors 21 and 22.

FIG. 10 shows a configuration of the magnetic sensor 20 having the single resistors 21 and 22. The output voltage Vout of the magnetic sensor 20 is expressed by the following equation.
Vout = V1-V2
= (ΔR1-ΔR2) × Iin (1)

  The single resistors 21 and 22 are driven by the constant current source Iin, and the inter-terminal voltages V1 and V2 are the output voltage Vout including the initial resistance value R and the influence of the magnetoresistance change ΔR.

  The single resistors 21 and 22 indicate that they are used as a two-terminal element rather than a four-terminal element such as a Wheatstone bridge, and the magnetoresistive effect element 1 is used alone, or a plurality of them are connected in series or in parallel. Including the case where it is used as a two-terminal element after being arranged.

  In the magnetic sensor 20 having sensitivity only in the X axis, the single resistors 21 and 22 as the magnetoresistive effect element 1 are arranged at the positions of the points (10) and (5) in the region 11 in FIG. Composed by taking the difference.

  At this time, when an external magnetic field 1Oe in the X-axis direction is applied, a magnetic field of 1.03 Oe is generated at the position of the point (10) in the region 11 from the table of FIG. A 0.41 Oe magnetic field is generated at the position. Therefore, an output voltage corresponding to a magnetic field change of 1.03-0.41 = 0.62 Oe can be obtained by taking an output difference from the single resistors at the positions of the points (10) and (5). On the other hand, for external magnetic fields in the Y-axis direction and the Z-axis direction, the X-axis components at the positions of the points (10) and (5) in the region 11 are the same (zero), and the output difference is zero. Become.

  The magnetic sensor having sensitivity only in the Y axis is configured by taking the difference between the point (3) and the point (1) in the region 11. At this time, when an external magnetic field 1 Oe in the Y-axis direction is applied, an output voltage corresponding to a magnetic field change of 0.08 − (− 0.08) = 0.16 Oe is obtained. On the other hand, the output difference is zero for external magnetic fields in the X-axis and Z-axis directions.

  Similarly, the magnetic sensor 20 having sensitivity only in the Z axis is configured by taking the difference between the point (2) and the point (8) in the region 11. At this time, when an external magnetic field 1 Oe in the Z-axis direction is applied, an output voltage corresponding to a magnetic field change of 0.08 − (− 0.08) = 0.16 Oe is obtained. On the other hand, the output difference is zero for external magnetic fields in the X-axis and Y-axis directions.

  In this example, since the difference between the voltages of the terminals of the single resistors 21 and 22 driven by the constant current source Iin is used, as shown in FIG. 10, the resistors 21 and 22 are used. It is not an essential requirement that one end of each is grounded (Gnd).

[Third example]
A third embodiment of the present invention will be described with reference to FIG. In addition, about the same part as each example mentioned above, the description is abbreviate | omitted and the same code | symbol is attached | subjected.

  This example shows a configuration example of a Wheatstone bridge type magnetic sensor 30 in which the magnetoresistive effect elements 31 to 34 are combined.

As a power source, an output voltage Vout when driven by a constant voltage source Vin is expressed by the following equation.
Vout = V1-V2
= (ΔR / R) × Vin (2)

The output voltage when driven by a constant current source Iin as a power source is expressed by the following equation.
Vout = V1-V2
= ΔR × Iin (3)

  R is an initial resistance value, and ΔR is a resistance change amount when a magnetic field is applied.

  When driven by the constant voltage source Vin, the output is proportional to ΔR and inversely proportional to R as shown in equation (2).

  The magnetoresistive effect elements 31 to 34 in this example generally have sensitivity in all three axial directions due to the influence of the magnetic convergence plate. In particular, when a magnetic field in the X-axis direction, which is the sensitivity axis direction of the magnetoresistive effect elements 31 to 34 itself, is applied, the resistance value always changes. Therefore, even when a sensor having sensitivity only in the Y-axis or the Z-axis is configured, if there is an offset magnetic field in the X-axis direction, the initial resistance value R is affected, and the output voltage Vout that is inversely proportional to R is , Subject to change depending on the magnitude of the offset magnetic field.

  On the other hand, when driven by the constant current source Iin, the output does not depend on R, but takes a form proportional only to ΔR, as shown in equation (3). Therefore, the output voltage Vout proportional to the resistance change ΔR due to the magnetic field change to be detected can be obtained without being affected by the offset magnetic field.

[Fourth example]
A fourth embodiment of the present invention will be described with reference to FIG. In addition, about the same part as each example mentioned above, the description is abbreviate | omitted and the same code | symbol is attached | subjected.

  This example shows a configuration example of the triaxial magnetic sensor 40.

  In the triaxial magnetic sensor 40, six magnetoresistive elements 1 having shape anisotropy are disposed below and outside the rectangular magnetic convergence plate 10. An electrode 41 at one end of each magnetoresistive effect element 1 is connected to a common ground, and a plurality of electrodes 42 at the other end are open to each other.

  Each magnetoresistive effect element 1 and the electrodes 41 and 42 are connected by an electrical wiring 43. The wiring 43 is wired on the substrate 44.

  Then, a triaxial magnetic sensor capable of detecting a triaxial magnetic field by connecting the output of a constant current source to the open end of the electrode 42, detecting the terminal voltage, and taking the difference from other elements. 40 can be configured.

[Fifth Example]
A fifth embodiment of the present invention will be described with reference to FIGS. In addition, about the same part as each example mentioned above, the description is abbreviate | omitted and the same code | symbol is attached | subjected.

  This example is an example of a manufacturing method of the multi-axis magnetic sensor 50 capable of detecting a magnetic field having two or more axes.

  First, the flow of the manufacturing method of the multi-axis magnetic sensor 50 will be described.

  In step S1, the pinned layer 2 in which the magnetization is fixed in the first direction X is formed on the plane of the semiconductor substrate 44 having LSI. Here, in FIG. 14, the LSI wiring 51 is shown.

  In step S2, the free layer 4 is formed on the pinned layer 2 whose magnetization is fixed in the first direction X via the intermediate layer 3, and a plurality of magnetoresistive effect elements 1 are created by processing this. . The free layer 4 can change the magnetization direction to a second direction Y different from the first direction X (for example, a second direction orthogonal to the first direction).

  In step S <b> 3, the LSI wiring 51 and the plurality of magnetoresistance effect elements 1 are electrically connected using the wiring 43.

  In step S4, a magnetic converging plate 10 as a magnetic converging body, which is a magnetic body, is disposed in a predetermined region 11 that spatially covers a position where at least one of the plurality of magnetoresistive effect elements 1 is disposed. Thereby, the multi-axis magnetic sensor 50 shown in FIGS. 13 and 14 is manufactured.

  Hereinafter, a specific manufacturing method will be described.

  13 and 14 show a configuration example of a three-axis magnetic sensor 50 as a multi-axis magnetic sensor.

  The triaxial magnetic sensor 50 is manufactured by the following manufacturing process.

First, an LSI and LSI wiring 51 are formed, and a TMR film is formed on the substrate 44 covered with an insulating film 52 such as SiO ₂ or SiN by sputtering in a magnetic field.

  Subsequently, the magnetization of the pinned layer 2 is fixed by performing a heat treatment in a magnetic field. Further, the magnetoresistive effect element 1 is formed using photolithography, ion milling, or the like.

  Next, the insulating film 52 in the connection portion with the LSI wiring 51 is removed by a method such as RIE or dry etching, and the metal constituting the wiring 43 is sputtered and lifted off. As a result, a lead wiring for connecting the LSI wiring 51 and the magnetoresistive effect element 1 is formed.

Next, an insulating film 53 such as SiO ₂ is formed.

  Finally, the magnetic converging plate 10 is formed, and the portion used for electrical connection with the outside is opened again.

  In FIG. 13, reference numeral 55 denotes a connection point between the LSI wiring 51 and the wiring 43, and 56 denotes an electrode pad for connection to the outside.

  As described above, the magnetic sensor 50 including the magnetoresistive effect element 1 can be manufactured on the substrate 44 on which the LSI is formed.

  The manufacturing process described above makes it possible to manufacture a multi-axis magnetic sensor using a magnetoresistive effect element having a pinned layer having only one magnetization direction, and can be pinned in a plurality of directions on a substrate constituting the multi-axis magnetic sensor. There is no need to provide a plurality of magnetoresistive elements whose layer magnetization is fixed. Therefore, a multi-axis magnetic sensor comprising a magnetoresistive effect element capable of detecting multi-axis magnetic field components can be obtained by a simpler manufacturing process than in the prior art.

[Sixth example]
A sixth embodiment of the present invention will be described with reference to FIG. In addition, about the same part as each example mentioned above, the description is abbreviate | omitted and the same code | symbol is attached | subjected.

  In this example, the free layer 2 is magnetized in a second direction Y orthogonal to the first direction X.

  Specifically, in FIG. 15, the magnetization of the free layer 2 is induced in a direction orthogonal to the magnetization direction of the pinned layer by the bias magnets 60 and 61 disposed in the vicinity of the magnetoresistive effect element 1.

  In the configuration of FIG. 15, the magnetic flux converging plate 10 as shown in FIG. 14 described above is disposed in the vicinity, but description thereof is omitted here.

  FIG. 15 shows a state in which the magnetization of the free layer 2 is induced in the direction Y perpendicular to the magnetization direction X of the pinned layer 2 by the bias magnets 60 and 61 formed in the vicinity of the magnetoresistive effect element 1.

In such a structure, after the magnetoresistive effect element 1 is formed, an insulating film such as SiO ₂ is formed, a ferromagnetic pattern having a high coercive force is formed by a sputter-lift-off process, and then the magnetization of the pinned layer 2 is formed. It is formed by performing a heat treatment in a magnetic field at a lower temperature than when the direction is fixed.

[Seventh example]
A seventh embodiment of the present invention will be described with reference to FIGS. In addition, about the same part as each example mentioned above, the description is abbreviate | omitted and the same code | symbol is attached | subjected.

  In this example, the magnetization of the free layer 2 is induced in a second direction Y orthogonal to the first direction X.

  Specifically, in FIG. 16, the magnetization of the free layer 2 is perpendicular to the magnetization direction of the pinned layer by a magnetic field generated by a current flowing through the electrical wiring 70 disposed in the vicinity of the magnetoresistive effect element 1. Be guided to.

  In the configuration of FIG. 16, the magnetic flux converging plate 10 as shown in FIG. 14 described above is disposed in close proximity, but description thereof is omitted here.

  FIG. 16 shows a state in which the magnetization of the free layer 2 is induced in the direction Y perpendicular to the magnetization of the pinned layer 2 by the magnetic field generated by the current flowing through the electric wiring 70 formed in the vicinity of the magnetoresistive effect element 1. Indicates.

  The induction of the magnetic field by the electric wiring is not limited to the method using the single electric wiring 70 as shown in FIG. 16, but a stronger bias magnetic field can be obtained by using the planar coil 71 or the solenoid coil as shown in FIG. Can be applied.

[Eighth Example]
An eighth embodiment of the present invention will be described with reference to FIGS. In addition, about the same part as each example mentioned above, the description is abbreviate | omitted and the same code | symbol is attached | subjected.

  In this example, the easy axis of the free layer 2 is induced in a second direction Y orthogonal to the first direction X.

  Specifically, in FIG. 19, the easy magnetization axis of the free layer 2 is induced in a direction orthogonal to the magnetization direction of the pinned layer due to shape anisotropy.

  FIG. 18A shows a state where magnetic poles are induced in a cross section perpendicular to the long axis direction when an external magnetic field is applied in the long axis direction of the magnetoresistive effect element 80 having shape anisotropy. Reference numeral 81 denotes a surface on which a magnetic pole is generated.

  When an external magnetic field is applied to the ferromagnetic material, the magnetostatic energy increases due to the influence of the demagnetizing field formed by the magnetic poles induced on the surface. As shown in FIG. 18A, when a magnetic field is applied in a direction with a high aspect ratio (elongated), the area in which the magnetic poles are generated in the major axis direction compared to the case where a magnetic field is applied in the vertical direction. Is small and magnetostatic energy is small.

  On the other hand, as shown in FIG. 18B, when a magnetic field is applied in the short axis direction with a low aspect ratio, a magnetic pole is generated on the side with a large surface area in the short axis direction, so that a magnetic field is applied in the long axis direction. The magnetostatic energy is higher than that. As a result, the direction parallel to the major axis direction becomes a direction in which magnetization is more easily performed. Therefore, by introducing shape anisotropy into the magnetoresistive effect element, the easy magnetization axis is induced in the major axis direction.

  FIG. 19 shows the magnetoresistive effect element 80 in the case where the magnetization direction of the pinned layer 2 and the easy axis of magnetization are orthogonal to each other by forming a shape with a high aspect ratio in a direction orthogonal to the magnetization direction of the pinned layer 2. It is a configuration. The aspect ratio for inducing the easy magnetization axis in the free layer 2 is preferably 1: 2 to 1: 200, and more preferably 1: 5 to 1: 100.

  In the configuration of FIG. 19, the magnetic flux converging plate 10 as shown in FIG. 14 described above is disposed in close proximity, but description thereof is omitted here.

[Ninth example]
A ninth embodiment of the present invention will be described with reference to FIG. In addition, about the same part as each example mentioned above, the description is abbreviate | omitted and the same code | symbol is attached | subjected.

  In this example, the easy axis of the free layer 2 is induced in a second direction Y orthogonal to the first direction X.

  Specifically, FIG. 20 shows an example of the shape of the magnetoresistive elements 90 and 91 for making the magnetization direction of the pinned layer 2 orthogonal to the easy axis of the free layer 2.

  20A and 20B are views seen from a direction perpendicular to the magnetosensitive surface of the magnetoresistive effect elements 90 and 91, FIG. 20A is a rectangle, and FIG. 20B is a meander shape. Indicates.

  The purpose of the shape of the magnetoresistive effect elements 90 and 91 is to provide shape anisotropy so that the magnetization direction of the pinned layer 2 is the minor axis direction and the major axis direction is perpendicular to the magnetization direction of the pinned layer 2. Therefore, since the magnetization direction of the pinned layer 2 and the easy axis of magnetization are perpendicular to each other, the shape is not limited to the rectangular shape and the meander shape in this example. It can be changed within the range to be achieved.

  In the configuration of FIG. 20, the magnetic flux converging plate 10 as shown in FIG. 14 is disposed close to the above, but the description thereof is omitted here.

1 magnetoresistive effect element 2 pinned layer 3 intermediate layer 4 free layer 10 magnetic converging means (magnetic material, magnetic converging plate)
DESCRIPTION OF SYMBOLS 11 Peripheral part 20 Magnetic sensor 21, 22 Single resistor 30 Magnetic sensor 31-34 Magnetoresistive element 40 Triaxial magnetic sensor 41, 42 Electrode 43 Wiring 44 Substrate 50 Triaxial magnetic sensor 51 LSI wiring 52 Insulating film 60, 61 Bias Magnet 70 Electrical wiring 80 Magnetoresistive element 90, 91 Magnetoresistive element

Claims (15)

A multi-axis magnetic sensor capable of detecting a three-axis magnetic field,
A plurality of magnetoresistive elements having a pinned layer in which magnetization is fixed in a first direction, and a free layer capable of changing the direction of the magnetization to a second direction different from the first direction;
Magnetic convergence means disposed in a predetermined region that spatially covers a position where at least one of the plurality of magnetoresistive elements is disposed;
The plurality of magnetoresistive elements are arranged in a region of the magnetic focusing means in plan view under the magnetic focusing means ,
The multi-axis magnetic sensor according to claim 1, wherein the magnetization direction of the pinned layer in each magnetoresistive element is fixed in the first direction .   2. The multi-axis according to claim 1, wherein the free layer has a magnetization easy axis induced in a second direction orthogonal to the first direction or magnetization induced in the second direction. 3. Magnetic sensor.   3. The multi-axis magnetic sensor according to claim 1, wherein the magnetic converging means is a magnetic converging body that changes the direction and magnitude of a magnetic field in a predetermined region with respect to an external magnetic field. The magnetoresistive effect element is configured as a single resistor,
4. The multi-axis magnetic field according to claim 1, wherein the single-resistor is driven by a constant current source to output a voltage difference between terminals obtained from at least two single-resistors. 5. Sensor. The magnetoresistive effect element is configured as a Wheatstone bridge,
4. The multi-axis magnetic sensor according to claim 1, wherein the Wheatstone bridge is driven by a constant current source. Further comprising a substrate containing Si on which LSI is formed,
6. The multi-axis magnetic sensor according to claim 1, wherein the LSI and the magnetoresistive element are electrically connected.   The multi-axis magnetic sensor according to claim 1, wherein the magnetoresistive element is a TMR element.   The multi-axis magnetic sensor according to claim 1, wherein the magnetoresistive element is a GMR element.   The multi-axis magnetic sensor according to claim 1, wherein the magnetization of the free layer is induced by a bias magnet arranged in the vicinity of the magnetoresistive effect element.   9. The multi-axis according to claim 1, wherein the magnetization of the free layer is induced by a magnetic field generated by a current flowing through an electric wiring disposed in the vicinity of the magnetoresistive effect element. Magnetic sensor.   9. The multi-axis magnetic sensor according to claim 1, wherein an easy axis of magnetization of the free layer is induced by shape anisotropy.   The multi-axis magnetic sensor according to claim 1, wherein a triaxial magnetic field can be detected using the plurality of magnetoresistive elements. A method of manufacturing a multi-axis magnetic sensor capable of detecting a three-axis magnetic field,
Forming a pinned layer with magnetization fixed in a first direction on a plane of one substrate;
On the pinned layer in which the magnetization is fixed in the first direction, a free layer capable of changing the direction of the magnetization to a second direction different from the first direction via an intermediate layer is formed. Thereby creating a plurality of magnetoresistive elements,
Providing a magnetic converging means in a predetermined region that spatially covers a position where at least one of the plurality of magnetoresistive elements is arranged,
In the step of generating the plurality of magnetoresistive elements, the plurality of magnetoresistive elements, in the lower of said magnetic flux concentrator means it is arranged in the region of the magnetic focusing means in a plan view, in each magnetoresistive element The method of manufacturing a multi-axis magnetic sensor , wherein the magnetization direction of the pinned layer is fixed in the first direction .   14. The multi-axis according to claim 13, wherein the free layer has a magnetization easy axis induced in a second direction orthogonal to the first direction or magnetization induced in the second direction. Manufacturing method of magnetic sensor.   15. The method of manufacturing a multi-axis magnetic sensor according to claim 13, wherein the magnetic converging means is a magnetic converging body whose magnetization direction and magnitude in a predetermined region are changed by a magnetic field.