JP2017103378A - Magnetoresistance effect element, magnetic sensor, manufacturing method of magnetoresistance effect element, and manufacturing method of magnetic sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetoresistance effect element which relatively enlarges an intensity range of a detectable external magnetic field, and a manufacturing method of the magnetoresistance effect element.SOLUTION: The magnetoresistance effect element comprises: a pinned layer in which a direction of magnetization is fixed; and a free layer which is laminated at one surface side of the pinned layer and in which the direction of magnetization is changed in accordance with an external magnetic field. The magnetoresistance effect element is characterized in that the direction of magnetization in the pinned layer is tilted relatively to the direction of magnetization in the free layer with no external magnetic field and that an angle of tilt is equal to or larger than 30° and equal to or smaller than 85°. A manufacturing method of the magnetoresistance effect element includes the steps of: laminating a pinned layer formation material and a free layer formation material at one face side of a substrate; and magnetizing the pinned layer formation material. In the magnetization step, the direction of a magnetic field to be applied to the pinned layer formation material is tilted relatively to the direction of magnetization in the free layer with no external magnetic field, and an angle of tilt is equal to or larger than 30° and equal to or smaller than 85°.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a magnetoresistive element, a magnetic sensor, a method for manufacturing a magnetoresistive element, and a method for manufacturing a magnetic sensor.

  Magnetoresistive elements that detect the intensity of a magnetic field by converting it into electrical resistance are widely used. In particular, a giant magnetoresistive element having a giant magnetoresistive effect (GMR) that can convert a small change in a magnetic field into a relatively large resistance change is used in, for example, a magnetic sensor.

  A giant magnetoresistive element is laminated on one side of a pinned layer in which the magnetization direction, that is, the magnetization direction is fixed (pinned) in advance in a certain direction, and the magnetization direction depends on the external magnetic field. And the resistance value changes according to the relative relationship between the magnetization direction of the pinned layer and the magnetization direction of the free layer.

  As a magnetic sensor using such a giant magnetoresistive effect element, for example, two pairs of giant magnetoresistive effect elements arranged so as to detect an X-direction component of an external magnetic field on an XY plane, and an external magnetic field X There has been proposed a magnetic sensor including a pair of giant magnetoresistive elements arranged in two-to-one pairs so as to detect a component in a direction perpendicular to the direction (see, for example, Japanese Patent Application Laid-Open No. 2007-212275). . In the magnetic sensor described in this publication, one of the two giant magnetoresistive elements that detect the component of the external magnetic field in the direction perpendicular to the X direction is centered on the axis in the X direction with respect to the XY plane. The other set is formed on a plane inclined in the negative direction of the Y direction around the axis in the X direction with respect to the XY plane. In this magnetic sensor, the component in the Y direction and the component in the Z direction of the external magnetic field can be derived by calculating the resistance value of the giant magnetoresistive effect element formed on these inclined surfaces.

  The magnetic sensor described in the above publication is used, for example, as an electronic compass that detects the geomagnetism as an external magnetic field and confirms the orientation of the sensor by calculating the relative direction of the geomagnetism. If the direction of the external magnetic field to be detected changes like an electronic compass and the absolute value of the external magnetic field strength is small, the error in the measured value due to hysteresis when the magnetization direction of the free layer is reversed is unacceptable. Become.

  Therefore, in the magnetic sensor described in the above publication, when there is no external magnetic field, the free layer is magnetized (initialized) by applying a bias magnetic field so that the free layer is magnetized in a certain direction. The magnetization direction of the free layer is not reversed due to the fluctuation. Specifically, in the magnetic sensor described in the above publication, each giant magnetoresistive element has a pair of bias magnet films connected to both ends in the longitudinal direction of the belt-shaped free layer, and the free layer is formed by the bias magnet film. Is initialized to be magnetized in the longitudinal direction.

  By the way, the giant magnetoresistive effect element needs a regularized heat treatment to magnetize the pinned layer in a certain direction by heating with a magnetic field applied during manufacture. The magnetic sensor described in the above publication is manufactured as a small sensor chip that is formed in a vertical and horizontal arrangement on a silicon wafer using semiconductor manufacturing technology and is cut out by dicing. Therefore, in ordering heat treatment to magnetize the pinned layer, a plurality of magnetic poles (electromagnets) arranged so that N poles and S poles alternately exist in the XY direction are arranged close to one surface of the wafer. Then, heating is performed while applying a magnetic field to the material forming the pinned layer.

  However, in such ordered heat treatment, the magnetic flux tends to bend in the direction perpendicular to the substrate due to the design restrictions of the magnetic pole to which the magnetic field is applied, and for all magnetoresistive elements arranged in parallel on the substrate. It is difficult to apply a magnetic field in the same direction. In particular, in the magnetic sensor in which a plurality of pairs of giant magnetoresistive effect elements are formed on a plurality of pairs of planes having different tilt angles as described in the above publication, the gradient of the magnetic field during the ordered heat treatment and the giant magnetoresistive effect element There is an element in which the effective magnetic field strength is reduced by overlapping the inclination. For this reason, in the magnetic sensor as described in the said gazette, there exists a possibility that the regularization (magnetization) of a pinned layer may become inadequate.

  As a result of the inventor's verification of the performance of the magnetic sensor as described in the above publication, if the pinned layer is insufficiently ordered, not only the detection sensitivity and the detection accuracy are lowered, but also the detectable external magnetic field. It was confirmed that the intensity range (dynamic range) was also narrowed. This is considered to be due to the reversal of the magnetization direction of the free layer caused by an external magnetic field having a relatively low strength when the pinned layer is not sufficiently ordered. In order to prevent reversal of the magnetization direction of the free layer, it is only necessary to increase the bias magnetic field. In this case, for example, the magnetic pole generating the bias magnetic field is enlarged, the power consumption is increased, and the detection sensitivity due to the influence of the bias magnetic field is detected. In addition, there are cases where the dynamic range of the magnetoresistive element cannot be sufficiently increased due to inconveniences such as a decrease in detection accuracy.

JP 2007-212275 A

  In view of the above problems, the present invention provides a magnetoresistive effect element and a magnetic sensor having a relatively large intensity range (dynamic range) of the detectable external magnetic field, a method for manufacturing the magnetoresistive effect element, and a method for manufacturing the magnetic sensor. The task is to do.

  As a result of diligent research, the present inventor has found that when the pinned layer is insufficiently ordered, the pinned layer has many parts that are microscopically magnetized in a direction different from the pinning direction, and the initial state of the free layer. It came to be considered that the micro portion in the pinned layer magnetized so as to have a component opposite to the direction of magnetization in the formation of a nucleus forms a reversal of the magnetization direction of the free layer. Then, the present inventor increases the dynamic range of the magnetoresistive effect element by reducing the micro part magnetized so as to have a component opposite to the magnetization direction in the initialization of the free layer in the pinned layer. The following invention was completed with the idea of being able to.

  The invention made to solve the above-described problems includes a pinned layer in which the direction of magnetization is fixed, and a free layer that is laminated on one surface side of the pinned layer and changes the direction of magnetization according to an external magnetic field. The magnetoresistive effect element includes a magnetization direction of the pinned layer that is inclined with respect to a magnetization direction in the absence of an external magnetic field of the free layer, and an inclination angle of 30 ° to 85 °. This is a magnetoresistive effect element.

  In the magnetoresistive element, the magnetization direction of the pinned layer is inclined by the above range with respect to the magnetization direction when there is no external magnetic field of the free layer, that is, the bias magnetic field direction for initialization. Even if the pinned layer is microscopically observed, there are very few micro portions magnetized so as to have a component opposite to the magnetization direction at the time of initializing the free layer. For this reason, in the magnetoresistive effect element, the magnetization direction of the free layer is not reversed until the external magnetic field becomes relatively strong. Therefore, the magnetoresistive effect element does not easily reverse the magnetization direction of the free layer, and the range in which the external magnetic field can be detected is relatively large. The “magnetization direction” is a macroscopic (macro) direction of magnetization of the entire layer, and whether the magnetic pole formed by polarization is an N pole or an S pole, that is, whether the magnetization direction is positive or negative. The “tilt angle” in the case where the polarization direction is the reverse direction is evaluated as 180 °.

  Another invention made to solve the above-described problems is a substrate, at least a pair of first magnetoresistive elements formed on the surface of the substrate and being the magnetoresistive elements, and at least a pair of second elements. A magnetoresistive effect element, wherein the first magnetoresistive effect element pair has opposite magnetization directions when there is no external magnetic field of each free layer, and there is no external magnetic field of the free layer The second magnetoresistive element arranged in the magnetization direction is formed on the surface of the substrate, and is laminated on one surface side of the pinned layer in which the magnetization direction is fixed, depending on the external magnetic field Each having a free layer whose magnetization direction changes, and the pair of the second magnetoresistive elements have opposite magnetization directions when there is no external magnetic field of each free layer, Resistance effect element The direction of magnetization when there is no external magnetic field of the free layer and the direction of magnetization when there is no external magnetic field of the free layer of the second magnetoresistive element are perpendicular to each other, and In the magnetic sensor, the arrangement direction of the second magnetoresistive effect element paired with the arrangement direction is inclined, and the inclination angle is 30 ° or more and 85 ° or less.

  Since the magnetic sensor includes at least a pair of first magnetoresistive elements formed from the magnetoresistive elements that are difficult to reverse the magnetization direction of the free layer, at least the first magnetoresistive elements of the external magnetic field are detected. The component to be detected can be detected in a relatively wide range. In addition, the magnetic sensor is arranged in a parallelogram lattice shape because the arrangement direction of the first magnetoresistive effect element forming a pair and the arrangement direction of the second magnetoresistive effect element forming a pair are inclined. Using the magnetic pole, the pinned layer of the first magnetoresistive element and the pinned layer of the second magnetoresistive element can be simultaneously pinned (ordered). Therefore, the magnetic sensor has a relatively wide dynamic range and can be provided at a relatively low cost.

  A plurality of pairs of first magnetoresistive elements arranged such that directions of magnetization in the absence of an external magnetic field of the free layer are parallel to each other; The free layer may be formed along a plurality of planes inclined at different angles with respect to the surface of the substrate about an axis parallel to the direction of magnetization when there is no external magnetic field of the free layer. In this way, the pinned layer and the free layer are formed along a plurality of planes inclined at different angles with respect to the surface of the substrate about an axis parallel to the direction of magnetization when there is no external magnetic field of the free layer. By providing a plurality of pairs of the first magnetoresistive effect elements, it is possible to detect two orthogonal components of the external magnetic field by bridge connecting the plurality of pairs of the first magnetoresistive effect elements. Together with the second magnetoresistive element, all three components of the external magnetic field can be detected. Further, when the first magnetoresistive element is formed along a plurality of planes inclined at different angles with respect to the surface of the substrate in this way, the effective magnetic field strength when magnetizing the pinned layer is increased. Although it is difficult, by suppressing the reversal of the magnetization direction of the free layer of the first magnetoresistance effect element by tilting the magnetization direction of the pinned layer with respect to the magnetization direction when there is no external magnetic field of the free layer, The dynamic range can be relatively increased.

  Further, another invention made to solve the above problem is that a pinned layer in which the direction of magnetization is fixed and laminated on one surface side of this pinned layer, and in a certain direction when there is no external magnetic field. A magnetoresistive effect element manufacturing method comprising a free layer that is magnetized and whose magnetization direction changes in response to an external magnetic field, the step of laminating a pinned layer forming material and a free layer forming material on one surface side of a substrate And the step of magnetizing the pinned layer forming material, wherein the direction of the magnetic field applied to the pinned layer forming material in the magnetization step is tilted with respect to the magnetization direction when there is no external magnetic field of the free layer, and the tilt angle thereof Is a manufacturing method of a magnetoresistive effect element characterized by being 30 ° or more and 85 ° or less.

  In the method of manufacturing the magnetoresistive element, the direction of the magnetic field applied to the pinned layer forming material in the magnetization step is inclined by the inclination angle in the above range with respect to the magnetization direction when there is no external magnetic field of the free layer, A magnetoresistive effect element in which the direction of magnetization of the pinned layer is inclined with respect to the direction of magnetization when there is no external magnetic field of the free layer, and the inclination angle is 30 ° to 85 ° can be manufactured. . The magnetoresistive element obtained by the magnetoresistive element manufacturing method has a component in which the magnetization direction at the time of initializing the free layer is opposite to the magnetization direction of the pinned layer. The external magnetic field can be detected in a relatively wide range.

  Further, another invention made to solve the above problems is a method of manufacturing a magnetic sensor using the method of manufacturing a magnetoresistive element, and forming a plurality of magnetoresistive elements on the surface of a substrate, The magnetization step includes a step of heating the pinned layer forming material in a state where a plurality of magnetic poles are arranged close to the substrate, and the direction of the magnetic field applied to the pinned layer forming material is free from the external magnetic field of the free layer This is a method of manufacturing a magnetic sensor in which the N pole and the S pole are displaced in the direction of magnetization when there is no external magnetic field of the free layer so as to be inclined with respect to the magnetization direction.

  In the method of manufacturing the magnetic sensor, the first magnetoresistive effect is obtained in the magnetization step by disposing the N poles and S poles of the plurality of magnetic poles in the direction of magnetization when there is no external magnetic field of the free layer. The direction of the magnetic field applied to the pinned layer forming material of the element can be tilted with respect to the direction of magnetization when there is no external magnetic field of the free layer, resulting in reversal of the magnetization direction of the free layer of the first magnetoresistive effect element It is difficult to efficiently manufacture a magnetic sensor that can detect an external magnetic field in a relatively wide range.

  The magnetoresistive effect element and magnetic sensor of the present invention, the magnetoresistive effect element obtained by the method of manufacturing the magnetoresistive effect element of the present invention, and the magnetic sensor obtained by the method of manufacturing the magnetic sensor of the present invention It can be detected in a wide range.

1 is a schematic plan view showing a magnetoresistive effect element according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the magnetoresistive effect element in FIG. 1. It is typical sectional drawing which shows an example of the laminated structure of a spin valve type giant magnetoresistive effect element. It is a schematic plan view of a magnetic sensor provided with the magnetoresistive effect element of FIG. It is a typical fragmentary sectional view of the magnetic sensor of FIG. It is a schematic diagram which shows arrangement | positioning of the magnetic pole for the ordering process of the magnetoresistive effect element of FIG. It is a schematic diagram which shows arrangement | positioning of the magnetic pole for the regularization process of the magnetic sensor of FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

[Magnetoresistance element]
A magnetoresistive effect element 1 according to an embodiment of the present invention shown in FIGS. 1 and 2 includes a pinned layer 2 in which at least the magnetization direction is fixed, and is laminated on one surface side of the pinned layer 2, and an external magnetic field. It is a magnetoresistive effect element provided with the detection part 4 formed from the laminated body which has the free layer 3 from which the direction of magnetization changes according to. In the detection unit 4, a spacer layer (nonmagnetic intermediate layer) 5 is further disposed between the pinned layer 2 and the free layer 3. The magnetoresistive effect element 1 is formed on the surface of a substrate 6 made of silicon, for example.

  The pinned layer 2 is formed of a hard magnetic material or a material capable of maintaining a state magnetized by an adjacent layer, and is preferably a thin film formed in a band shape in plan view as illustrated. The free layer 3 is formed of a soft magnetic material, and is preferably a thin film having a belt-like shape in plan view and laminated so as to have substantially the same shape as the pinned layer 2 when viewed in the normal direction of the pinned layer 2. The spacer layer 5 is formed of a conductive non-magnetic material, and is preferably a thin film having a belt-like shape in plan view and laminated so as to have substantially the same shape as the pinned layer and the free layer 3 when viewed in the normal direction of the pinned layer 2.

  The magnetoresistive effect element 1 is arranged on both sides of the pinned layer 2 and the free layer 3 so as to magnetize the free layer 3 in the absence of an external magnetic field, and applies a magnetic field to the free layer 3 as shown in the figure. It is preferable to have a pair of magnet layers (a first magnet layer 7a whose free layer 3 side is magnetized to N pole and a second magnet layer 7b whose free layer 3 side is magnetized to S pole). The first magnet layer 7a and the second magnet layer 7b that are paired with each other apply a bias magnetic field in the direction indicated by the arrow F in the figure to the free layer 3 so that the free layer 3 is formed when there is no external magnetic field. Magnetized in the direction of arrow F. It is preferable that the magnetization direction F in the absence of the external magnetic field of the free layer 3 coincides with the longitudinal directions of the pinned layer 2 and the free layer 3. In addition, you may form the 1st magnet layer 7a and the 2nd magnet layer 7b with an electroconductive material so that it can be used as a part of the electrode which extracts the signal from the said magnetoresistive effect element 1, or an electric circuit.

  The first magnet layer 7a and the second magnet layer 7b can be thin films formed of a hard magnetic material such as CoCrPt, for example. The material forming the first magnet layer 7a and the second magnet layer 7b has a smaller coercive force than the material forming the pinned layer 2 so that the material can be magnetized without changing the magnetization direction of the pinned layer 2 (with a weak magnetic field). It is preferable to use a material that can be magnetized.

  The magnetoresistive element 1 detects a component in a direction parallel to the magnetization direction of the pinned layer 2 (the direction indicated by the arrow P in the figure). In the magnetoresistive effect element 1, the direction of magnetization of the pinned layer 2 (direction indicated by an arrow P in the figure) is the direction of magnetization when there is no external magnetic field of the free layer 3 (initialization direction or first magnet layer). 7a and the direction of the bias magnetic field applied from the second magnet layer 7b).

  The lower limit of the tilt angle α with respect to the direction F of the bias magnetic field in the magnetization direction P of the pinned layer 2 is 30 °, preferably 50 °, and more preferably 55 °. On the other hand, the upper limit of the inclination angle α is 85 °, preferably 75 °, and more preferably 65 °. When the tilt angle α is less than the lower limit, the sensitivity direction is close to the direction of the bias magnetic field, so the detection accuracy of the external magnetic field (linearity of the resistance value change) and the detection sensitivity (resistance value change with respect to the change of the external magnetic field). (Size) may be insufficient. Conversely, when the tilt angle α exceeds the upper limit, the effect of suppressing the reversal of the magnetization direction of the free layer 3 may be insufficient.

  The average width of the detection unit 4 (laminated body including the pinned layer 2 and the free layer 3) can be set to 2 μm or more and 20 μm or less, for example. Moreover, as an average length of the detection part 4, it is 50 micrometers or more and 500 micrometers or less, for example.

<Advantages>
The magnetoresistive element 1 has the pinned layer 2 in the free layer 3 because the tilt angle α with respect to the magnetization direction F when the magnetization direction of the pinned layer 2 is free from the external magnetic field of the free layer 3 is within the above range. Substantially does not have a micro portion magnetized so as to have a component opposite to the magnetization direction F at the time of initialization. For this reason, the magnetoresistive effect element 1 hardly causes reversal of the magnetization direction of the free layer, and has a relatively large range in which an external magnetic field can be detected.

  The magnetoresistive element 1 only needs to include a detection unit 4 formed from a stacked body including the pinned layer 2 and the free layer 3, and the stacked structure of the detection unit 4 may be a spin valve, for example. Any laminated structure of giant magnetoresistive elements such as a giant magnetoresistive element can be adopted. That is, the magnetoresistive effect element 1 is made of, for example, a diamagnetic material, and is laminated on the surface of the pinned layer 2 opposite to the free layer 3 so that the pinning layer 2 can secure the magnetization of the pinned layer 2. You may further provide the capping layer which covers the surface of the layer 3, the diffusion prevention layer etc. which prevent that the material of each layer diffuses into the adjacent layer. Further, the vertical relationship between the pinned layer 2 and the free layer 3 in the magnetoresistive effect element 1 (stacking order with respect to the substrate 6) is also arbitrary.

  As a non-limiting specific example, FIG. 3 shows an example of a laminated structure of the detection unit 4 of the spin valve type giant magnetoresistive element. The detection unit 4 of the spin-valve giant magnetoresistive element includes a free layer 12, a first diffusion prevention layer 13, a spacer layer 14, a pinned layer 15, a pinning layer 16, and a capping layer 17 in this order on a substrate 11. Are stacked.

(substrate)
The substrate 11 is a silicon substrate used as a semiconductor substrate.

(Free layer)
The free layer 12 is formed of a soft magnetic material (a material having a relatively high magnetic permeability and a small hysteresis), and is laminated on the first magnetic layer 12a and formed of a soft magnetic material. And a second magnetic layer 12b. The first magnetic layer 12a is made of, for example, amorphous CoZrNb, and has an average thickness of, for example, 5 nm or more and 15 nm or less, typically 8 nm. On the other hand, the second magnetic layer 12b is made of, for example, NiFe and has an average thickness of, for example, 2 nm or more and 5 nm or less, typically 3.3 nm.

(First diffusion prevention layer)
The first diffusion preventing layer 13 is made of, for example, CoFe, and has an average thickness of, for example, 1 nm or more and 3 nm or less. Since CoFe is a soft magnetic material, the diffusion prevention layer 13 is magnetized in accordance with an external magnetic field in the same manner as the free layer 12 and can be considered as a part of the free layer 12.

(Spacer layer)
The spacer layer 14 is formed from, for example, a conductive material. Specifically, the spacer layer 13 is made of, for example, Cu and has an average thickness of, for example, 1 nm to 5 nm, typically 2.4 nm.

(Pinned layer)
The pinned layer 15 is made of a ferromagnetic material (having a relatively high magnetic permeability). Specifically, the pinned layer 15 is made of, for example, CoFe, and has an average thickness of, for example, 1 nm to 5 nm, typically 2.2 nm.

(Pinning layer)
The pinning layer 16 is made of an antiferromagnetic material (having a relatively small permeability). Specifically, the pinning layer 17 is made of, for example, a PtMn alloy containing 45 mol% or more and 55 mol% or less of Pt, and has an average thickness of 15 nm or more and 40 nm or less, typically 24 nm.

(Capping layer)
The capping layer 17 is made of titanium or tantalum, and has an average thickness of, for example, 1 nm to 5 nm, typically 2.5 nm.

  In this spin-valve giant magnetoresistive element, the pinned layer 15 has its magnetization fixed in a certain direction by the pinning layer 17, and the free layer 12 is magnetized according to the fluctuation of the external magnetic field. When the magnetization direction of the free layer 12 coincides with the magnetization direction of the pinned layer 15, the resistance of the spacer layer 13 is minimized, and the magnetization direction of the free layer 12 is opposite to the magnetization direction of the pinned layer 15. As a result, the resistance of the spacer layer 13 is maximized.

[Magnetic sensor]
FIG. 4 shows a magnetic sensor according to an embodiment of the present invention including the magnetoresistive effect element 1 of FIG. The magnetic sensor detects XYZ triaxial components of the external magnetic field orthogonal to each other, and is mainly used for an electronic compass for detecting the direction of geomagnetism relative to itself and confirming the direction. A triaxial magnetic sensor.

  The magnetic sensor is formed on the surface of the substrate 6, at least a pair of the magnetoresistive effect element 1 (hereinafter referred to as a first magnetoresistive effect element) formed on the surface of the substrate 6, and the substrate 6. And at least a pair of second magnetoresistance effect elements 8. Specifically, in the magnetic sensor of FIG. 4, as shown in the figure, two pairs (four), one pair of two (total eight) first magnetoresistive effect elements 1 and two pairs (four). One set (a total of four) second magnetoresistive elements 8 is provided.

  In the magnetic sensor, the substrate 6 typically has a square shape whose side edge is along the X direction and the Y direction, and preferably has a planar shape in the positive direction. The average length of one side of the substrate 6 can be, for example, 0.2 mm or more and 2 mm or less. Moreover, as average thickness of the board | substrate 6, it can be 0.3 mm or more and 1 mm or less, for example.

  Each pair of the first magnetoresistive effect elements 1 is formed by being divided into two regions near the center of two sides facing each other in the X direction of the substrate 6 (each extending in the Y direction). Each pair of the second magnetoresistive effect elements 8 is formed by being distributed in the vicinity of two other sides facing the Y direction of the substrate 6 (extending in the X direction). The plurality of first magnetoresistive elements 1 or the plurality of second magnetoresistive elements 8 distributed to the vicinity region of the same side of the substrate 6 are parallel to the sides of the substrate 6 in the longitudinal direction (X direction or In the Y direction). The interval (gap) in plan view of the plurality of first magnetoresistive elements 1 or the plurality of second magnetoresistive elements 8 distributed to the vicinity of the same side of the substrate 6 is, for example, 1 μm or more and 10 μm or less. The

  In the magnetic sensor, the paired first magnetoresistive effect elements 1 have magnetization directions F in opposite directions when there is no external magnetic field of the free layer. The paired first magnetoresistive elements 1 are arranged to face the magnetization direction F when there is no external magnetic field of the free layer. The first magnetoresistance effect element 1 is arranged so that the magnetization direction F in the absence of the external magnetic field of the free layer is the X direction. That is, the center of the group of the first magnetoresistive effect elements 1 arranged near one side of the substrate 6 is connected to the center of the group of the first magnetoresistive effect elements 1 arranged near the opposite side. The direction is parallel to the X direction.

  At least a pair of second magnetoresistive elements 8 each have a pinned layer whose magnetization direction is fixed and a free layer that is laminated on one surface side of the pinned layer and whose magnetization direction changes according to an external magnetic field. However, the magnetization directions Fa when there is no external magnetic field of the free layer are opposite to each other. The second magnetoresistive element 8 is arranged such that the magnetization direction Fa when there is no external magnetic field of the free layer, that is, the longitudinal direction of the stacked body (detection unit) including the pinned layer and the free layer is the Y direction. Is done. The second magnetoresistive element 8 has the same laminated structure as the first magnetoresistive element 1, but the magnetization direction Pa of the pinned layer is not limited. The magnetization direction Pa of the pinned layer of the second magnetoresistive element 8 is typically the X direction perpendicular to the magnetization direction Fa when there is no external magnetic field of the free layer. Like the resistance effect element 1, it may be inclined with respect to the magnetization direction Fa when there is no external magnetic field of the free layer. The pair of second magnetoresistive elements 8 is arranged in a direction parallel to the magnetization direction P of the pinned layer of the first magnetoresistive element 1. That is, the center of the group of second magnetoresistive effect elements 8 arranged in the vicinity of one side of the substrate 6 is connected to the center of the group of second magnetoresistive effect elements 8 arranged in the vicinity of the side facing the substrate 6. The direction is parallel to the magnetization direction P of the pinned layer of the first magnetoresistance effect element 1.

  In addition, in the cross section perpendicular to the longitudinal direction of the laminate including the pinned layer and the free layer shown in FIG. 5 (the direction of magnetization F when there is no external magnetic field of the free layer), a plurality of pairs of first magnetoresistive elements 1 are The pinned layer and the free layer are formed along a plurality of planes inclined at different angles with respect to the surface of the substrate 6 around an axis parallel to the direction of magnetization F when there is no external magnetic field of the free layer. . More specifically, the two sets of the first magnetoresistive effect element 1 are respectively arranged on planes inclined in different directions (preferably at equal absolute angles), and one set of the first magnetoresistive effect element 1 is provided. Of the first magnetoresistive element 1 is inclined in the Y-axis negative direction with reference to the Z direction. The inclined surface forming the first magnetoresistance effect element 1 can be provided by forming a trapezoidal or triangular groove on the surface of the substrate 6 as shown in the figure, for example. The absolute value of the inclination angle with respect to the surface (XY plane) of the flat substrate 6 on which the first magnetoresistive effect element 1 is disposed can be, for example, 25 ° to 65 °.

  In the magnetic sensor, a plurality of pairs of first magnetoresistive effect elements 1 are bridge-connected, or the resistance values of the first magnetoresistive effect elements 1 are processed to obtain two components of the external magnetic field in the Y direction and the Z direction. Can be detected. Note that the bridge connection or calculation processing for detecting components in the Y direction and the Z direction of the external magnetic field is described in detail in, for example, Japanese Patent Application Laid-Open No. 2007-212275 and the like, and is a well-known technique. Detailed description is omitted in this specification.

  Using the second magnetoresistive effect element 8, as in the case of the first magnetoresistive effect element 1, the component in the X direction of the external magnetic field can be derived by the bridge connection or the calculation processing of the resistance value of each element. Therefore, the magnetic sensor includes a plurality of pairs of first magnetoresistive effect elements 1 that can detect the Y-direction and Z-direction components of the external magnetic field, and a second magnetoresistive effect element 8 that can detect the X-direction components of the external magnetic field. By this, it is possible to detect all the XYZ three-axis components of the external magnetic field.

  Furthermore, in the magnetic sensor, as shown in FIG. 4, the arrangement direction D of the first magnetoresistive effect elements 1 forming a pair (in the case of multiple pairs, the direction connecting the centers of the elements, and the external magnetic field of the free layer is And the direction of arrangement Da of the paired second magnetoresistive effect elements 8 (the direction connecting the centers of the elements when there are a plurality of pairs) are inclined at an inclination angle β. . In other words, the paired second magnetoresistive element 8 has a direction perpendicular to the magnetization direction Fa when there is no external magnetic field of the free layer (in the case where there is no external magnetic field of the free layer of the first magnetoresistive element 1). They are offset in opposite directions in the direction of magnetization F).

  The lower limit of the inclination angle β between the arrangement direction D of the paired first magnetoresistance effect elements 1 and the arrangement direction Da of the paired second magnetoresistance effect elements 8 is 30 °, preferably 50 °, 65 ° is more preferable. On the other hand, the upper limit of the inclination angle β is 85 °, preferably 75 °, and more preferably 70 °. In addition, this inclination angle β is preferably equal to the inclination angle α of the magnetization direction P of the pinned layer 2 of the magnetoresistive element 1 with respect to the direction F of the bias magnetic field. If the tilt angle β is less than the lower limit, it may be difficult to order the pinned layer 2 of the magnetoresistive element 1 to have the tilt angle α. Conversely, even when the tilt angle β exceeds the upper limit, it may be difficult to order the pinned layer 2 of the magnetoresistive element 1 to have the tilt angle α.

  That is, the magnetic sensor has parallel four sides as will be described later, since the arrangement direction of the paired first magnetoresistance effect elements 1 and the arrangement direction of the paired second magnetoresistance effect elements 8 are inclined. The pinned layer of the first magnetoresistive effect element 1 and the pinned layer of the second magnetoresistive effect element 8 can be pinned (regulated) relatively easily and accurately by using magnetic poles arranged in a lattice pattern.

<Advantages>
Since the magnetic sensor includes at least a pair of first magnetoresistive elements 1 that are difficult to reverse the magnetization direction of the free layer, at least a component detected by the first magnetoresistive element 1 of the external magnetic field is relatively wide. Can be detected.

[Method for Manufacturing Magnetoresistive Element]
The magnetoresistive effect element 1 according to an embodiment of the present invention includes a step of laminating a pinned layer forming material and a spacer layer forming material on one surface side of the substrate 6 and a step of magnetizing the pinned layer forming material. It can be manufactured by a method for manufacturing a magnetoresistive effect element.

  In the laminating step, in addition to the spacer layer forming material and the free layer forming material, materials for forming each layer constituting the detection unit 4 of the magnetoresistive effect element 1 are sequentially stacked. The order in which the layers are laminated is appropriately selected according to the laminated structure of the magnetoresistive effect element 1.

  In the magnetization step, the direction of the magnetic field applied to the pinned layer forming material is inclined with respect to the magnetization direction F when there is no external magnetic field of the free layer. Thereby, a pinned layer magnetized in the direction along the direction of the magnetic field applied to the pinned layer forming material is formed. Therefore, the inclination angle with respect to the magnetization direction F when there is no external magnetic field of the free layer in the direction of the magnetic field applied to the pinned layer forming material is directly outside the free layer in the magnetization direction P of the pinned layer in the magnetoresistive effect element 1. It becomes the inclination angle α with respect to the direction of magnetization F when there is no magnetic field.

  Specifically, as shown in FIG. 6, the N pole and the S pole arranged so as to sandwich the pinned layer forming material in the width direction are positioned in the magnetization direction F (X direction) when there is no external magnetic field of the free layer. Shift and place. That is, the direction connecting the N pole and the S pole sandwiching the magnetoresistive effect element 1 (the direction of the magnetic field formed by these magnetic poles) has the inclination angle α described above with respect to the longitudinal direction of the magnetoresistive effect element 1. Placed in.

  More specifically, the N pole and S pole for applying a magnetic field to the magnetoresistive effect element 1 are a pair of magnet layers 7a and 7b for the N pole for magnetizing the pinned layer to magnetize the free layer. In the longitudinal direction of the magnetoresistive effect element 1, the south pole for magnetizing the pinned layer is on the second magnet layer 7b side, which is the south pole, on the first magnet layer 7a side, which is the north pole, It is offset with respect to the center.

  By using a plurality of magnetic poles arranged in this way, the direction of the magnetic field applied to the pinned layer forming material in the magnetization step can be tilted with respect to the magnetization direction F when there is no external magnetic field in the free layer. The magnetoresistive effect element 1 that can hardly detect the reversal of the magnetization direction of the free layer and can detect an external magnetic field in a relatively wide range can be efficiently manufactured.

[Method of manufacturing magnetic sensor]
The above-described magnetic sensor including the magnetoresistive effect element 1 forms a plurality of first magnetoresistive effect elements 1 and second magnetoresistive effect elements on the surface of the substrate 6 by using the magnetoresistive effect element manufacturing method. Can be manufactured.

  In the method for manufacturing the magnetic sensor, the magnetization step may include a step of heating the pinned layer forming material in a state where a plurality of magnetic poles are arranged in the vicinity of the substrate 6 in a wafer state before dicing (cutting).

  Further, the magnetic sensor manufacturing method includes a step of laminating a magnet forming material on both ends of the magnetoresistive element forming region on one side of the substrate 6, and magnetizing the magnet forming material after the magnetizing step. You may further provide the process of forming the 1st magnet layer 7a and the 2nd magnet layer 7b which apply a bias magnetic field to a free layer.

  FIG. 7 shows the arrangement of magnetic poles used in the magnetization process. As shown in the figure, the plurality of magnetic poles used in the magnetization process are N poles that are alternately arranged in a direction (Y direction) perpendicular to the magnetization direction F when there is no external magnetic field of the free layer of the magnetoresistive element 1. And S pole. The plurality of magnetic poles are arranged such that the N pole and the S pole are displaced in the magnetization direction F (X direction) when there is no external magnetic field of the free layer. That is, the direction connecting the N pole and the S pole sandwiching the magnetoresistive effect element 1 (the direction of the magnetic field formed by these magnetic poles) has the inclination angle α described above with respect to the longitudinal direction of the magnetoresistive effect element 1. Placed in.

  Further, when the magnetic sensor in which the first magnetoresistive effect element 1 and the second magnetoresistive effect element 8 are formed on the substrate 6 is formed, as shown in FIG. As described above, the magnetic poles are arranged in a plurality of rows in the X direction, with the N and S poles shifted in the X direction and arranged in the Y direction. In this case, the N poles and the S poles are alternately arranged in the magnetization direction F when there is no external magnetic field of the free layer of the magnetoresistive effect element 1. Thereby, the magnetic field of the X direction which magnetizes also the pinned layer of the 2nd magnetoresistive effect element 8 simultaneously with the magnetic pole for magnetizing the pinned layer of the 1st magnetoresistive effect element 1 can be formed.

  Further, the offset amount of these magnetic poles in the X direction is arranged so that the direction connecting the N pole and the S pole has an inclination angle α with respect to the longitudinal direction of the magnetoresistive effect element 1. Since the amount of offset from the center in the X direction of the second magnetoresistive element 8 is equal, the N pole and the S pole are arranged at an equal distance from the second magnetoresistive element 8. Thereby, the pinned layer of the 2nd magnetoresistive effect element 8 is magnetized appropriately.

  The magnetic sensor manufacturing method uses a plurality of magnetic poles arranged as described above to simultaneously apply a magnetic field to the pinned layer forming material of the first magnetoresistive effect element 1 and the pinned layer forming material of the second magnetoresistive effect element 8. Since the first magnetoresistive effect element 1 and the second magnetoresistive effect element 8 can be efficiently formed, the magnetic sensor including the magnetoresistive effect element 1 can be efficiently manufactured.

  In the magnetic sensor manufacturing method, the magnetization directions of the free layers of the first magnetoresistive effect element 1 and the second magnetoresistive effect element 8 are directed to the inside of the magnetic sensor and to the outside of the magnetic sensor. Although the direction of the bias magnetic field to be applied to the free layer is opposite (the NS of the magnetic pole provided for this purpose is different), the polarity of the output of the magnetic sensor differs. Therefore, it is only necessary to confirm the direction of magnetization of the free layer for mounting, and there is no practical problem.

[Other Embodiments]
The said embodiment does not limit the structure of this invention. Therefore, in the above-described embodiment, components of each part of the above-described embodiment can be omitted, replaced, or added based on the description and common general knowledge of the present specification, and they are all interpreted as belonging to the scope of the present invention. Should.

  The magnetoresistive element may not have a magnet layer for applying a bias magnetic field. A magnetoresistive effect element that does not have a magnet layer is used together with an external magnet that forms a bias magnetic field.

  The magnetoresistive element has a plurality of detectors that are physically arranged in parallel and electrically connected in series, as described in, for example, Japanese Patent Application Laid-Open No. 2007-212275. Also good.

  In addition, the magnetoresistive element is not limited to a CIP (Current In Plane) structure in which a current flows in parallel to the surfaces of the pinned layer and the free layer as in the above-described embodiment, and the magnetoresistive effect element is formed on the surfaces of the pinned layer and the free layer. It may have a CPP (Current Perpendicular to Plane) structure in which current flows vertically.

  The magnetoresistive element may be used in a uniaxial magnetic sensor that detects an external magnetic field in one direction.

  The magnetic sensor is not limited to the first magnetoresistive effect element that is inclined with respect to the surface of the substrate, and the first magnetoresistive effect element and the second magnetoresistive effect element are arranged along the surface of the substrate. It may be a biaxial sensor that detects an external magnetic field in the XY directions.

  In the magnetic sensor, the longitudinal direction of the first magnetoresistive element and the second magnetoresistive element (the direction of magnetization when there is no external magnetic field of the free layer) may be inclined.

  In the magnetic sensor, the arrangement direction of the second magnetoresistance effect elements may be perpendicular to the arrangement direction of the first magnetoresistance effect elements. In other words, the magnetic sensor may be one in which the second magnetoresistive element is not offset in the magnetization direction when there is no external magnetic field in the free layer of the first magnetoresistive element.

  The magnetic sensor is not limited to one manufactured by the magnetic sensor manufacturing method. As a specific example, in the ordering process of the magnetoresistive effect element, the N pole and the S pole for applying a magnetic field are arranged so as to be displaced in the magnetization direction when there is no external magnetic field of the free layer. Not limited to this, a rod-like shape in plan view and an inclination arranged with respect to the direction of magnetization when there is no external magnetic field of the free layer may be used.

  The magnetoresistive effect element and the magnetic sensor can be particularly preferably used as a sensor for detecting geomagnetism.

1 Magnetoresistive effect element (first magnetoresistive effect element)
2 pinned layer 3 free layer 4 detector 5 spacer layer 6 substrate 7a first magnet layer 7b second magnet layer 8 second magnetoresistive element 11 substrate 12 free layer 12a first magnetic layer 12b second magnetic layer 13 first diffusion Preventing layer 14 Spacer layer 15 Pinned layer 16 Pinning layer 17 Capping layer D, Da Magnetoresistive effect element arrangement direction F, Fa Free layer magnetization direction P in the absence of external magnetic field, Pa Pinned layer magnetization direction α Bias Tilt angle β with respect to the direction F of the magnetic field Tilt angle between the arrangement direction of the first magnetoresistance effect element and the arrangement direction of the second magnetoresistance effect element

Claims (5)

A magnetoresistive effect element comprising a pinned layer in which the direction of magnetization is fixed, and a free layer that is stacked on one surface side of the pinned layer and changes the direction of magnetization according to an external magnetic field,
The magnetoresistive element according to claim 1, wherein the magnetization direction of the pinned layer is inclined with respect to the magnetization direction in the absence of an external magnetic field of the free layer, and the inclination angle is 30 ° or more and 85 ° or less. A substrate,
It is formed on the surface of the substrate, and includes at least a pair of first magnetoresistive elements that are the magnetoresistive elements according to claim 1, and at least a pair of second magnetoresistive elements,
The first magnetoresistive element pairs are arranged in opposite directions of magnetization when there is no external magnetic field of each free layer, and arranged in the direction of magnetization when there is no external magnetic field of the free layer,
The second magnetoresistive effect element is formed on the surface of the substrate, and is stacked on a pinned layer whose magnetization direction is fixed and on one surface side of the pinned layer, and the magnetization direction changes according to an external magnetic field. Each has a free layer,
When the second magnetoresistive element pair has no external magnetic field of each free layer, the magnetization directions are opposite to each other,
The direction of magnetization when there is no external magnetic field of the free layer of the first magnetoresistive element is perpendicular to the direction of magnetization when there is no external magnetic field of the free layer of the second magnetoresistive element,
The magnetic sensor in which the arrangement direction of the first magnetoresistive effect element forming a pair and the arrangement direction of the second magnetoresistive effect element forming a pair are inclined, and the inclination angle is 30 ° to 85 °. Comprising a plurality of pairs of the first magnetoresistive elements arranged such that the directions of magnetization in the absence of an external magnetic field of the free layer are parallel to each other;
A plurality of pinned layers and free layers of the plurality of pairs of first magnetoresistive elements that are inclined at different angles with respect to the surface of the substrate about an axis parallel to the direction of magnetization when there is no external magnetic field of the free layer The magnetic sensor according to claim 2, wherein the magnetic sensor is formed along a plane. A pinned layer in which the direction of magnetization is fixed, a free layer that is laminated on one side of the pinned layer, is magnetized in a certain direction when there is no external magnetic field, and changes the direction of magnetization according to the external magnetic field; A magnetoresistive effect element manufacturing method comprising:
Laminating a pinned layer forming material and a free layer forming material on one side of the substrate;
Magnetizing the pinned layer forming material, and
The direction of the magnetic field applied to the pinned layer forming material in the magnetization step is inclined with respect to the magnetization direction in the absence of an external magnetic field of the free layer, and the inclination angle is 30 ° to 85 °. A method of manufacturing a resistance effect element. A method of manufacturing a magnetic sensor using the method of manufacturing a magnetoresistive element according to claim 4, wherein a plurality of magnetoresistive elements are formed on a surface of a substrate,
The magnetization step includes a step of heating the pinned layer forming material in a state where a plurality of magnetic poles are arranged in proximity to the substrate;
The plurality of magnetic poles have N and S poles alternately arranged in a direction perpendicular to the direction of magnetization when there is no external magnetic field of the free layer of the magnetoresistive effect element, and are applied to the pinned layer forming material The N pole and the S pole are arranged so as to be displaced in the magnetization direction when there is no external magnetic field of the free layer so that the direction of the magnetic field to be tilted with respect to the magnetization direction when there is no external magnetic field of the free layer. Manufacturing method of magnetic sensor.

Images