magnetic sensor

Abstract

A magnetic sensor 100 according to one aspect of the present invention comprises: a magnetoresistive element 10 which has a fixed magnetic layer 11, a free magnetic layer 12, and an intermediate layer 13 formed between the fixed magnetic layer 11 and the free magnetic layer 12, and has a sensitivity axis in a first direction; wiring 20 having a first surface 21 which is positioned in a second direction that is along the stacking direction of the magnetoresistive element 10 and crosses the first direction of the magnetoresistive element 10, and which faces the magnetoresistive element 10; and a magnetic permeable part 30 composed of a ferromagnetic body and provided to at least a portion of a surface other than the first surface 21 among the surfaces of the wiring 20, wherein the wiring 20 is disposed so as to apply, in the first direction, an induction magnetic field generated during energization to the magnetoresistive element 10, and can therefore efficiently apply the induction magnetic field of the wiring disposed in the vicinity of the magnetoresistive element 10.

Description

[Technical Field]

[0001] The present invention relates to a magnetic sensor. [Background technology]

[0002] Patent Document 1 discloses a magnetic sensor having a substrate and a laminated portion arranged on the substrate, the laminated portion including a magnetization free layer whose magnetization changes in response to an external magnetic field, a magnetization fixed layer whose magnetization is fixed in a first direction, and a non-magnetic layer arranged between the magnetization free layer and the magnetization fixed layer, the magnetic sensor comprising: a magnetic sensing unit that outputs a signal in response to the external magnetic field; and a magnetic field generating unit that applies a bias magnetic field to the magnetization free layer, wherein when the bias magnetic field is not applied to the magnetization free layer, the magnetization direction of the magnetization free layer is approximately parallel or approximately anti-parallel to the first direction, and the magnetic sensor is configured to calculate the component of the external magnetic field in the second direction based on a first output which is the output of the magnetic sensing unit when a first bias magnetic field including a positive component is applied to the magnetization free layer in a second direction perpendicular to the first direction in a top view, and a second output which is the output of the magnetic sensing unit when a second bias magnetic field including a negative component is applied to the magnetization free layer.

[0003] In the invention disclosed in Patent Document 1, a specific example of a magnetic field generating unit is a wiring unit provided in the stacking direction of the stacked unit, and an induced magnetic field from the current-carrying wiring unit is applied to the magnetization free layer of the stacked unit as a bias magnetic field. The external magnetic field is measured under conditions where bias magnetic fields are applied in different directions, and 1 / f noise is removed based on these measurement results. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-115972 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0005] When measuring an external magnetic field while receiving an induced magnetic field from wiring placed near a magnetoresistive element, as in the magnetic sensor disclosed in Patent Document 1, it can be difficult to increase the strength of the induced magnetic field by increasing the amount of current flowing through the wiring due to reasons such as the small cross-sectional area of ​​the wiring and the structural difficulty of dissipating Joule heat from the wiring.

[0006] SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a magnetic sensor capable of efficiently applying an induced magnetic field from wiring arranged in the vicinity of a magnetoresistive element. [Means for solving the problem]

[0007] In order to solve the above problem, one embodiment of the magnetic sensor of the present invention comprises a magnetoresistive element having a fixed magnetic layer, a free magnetic layer, and an intermediate layer formed between the fixed magnetic layer and the free magnetic layer, and having a sensitivity axis in a first direction; wiring located in a second direction along the stacking direction of the magnetoresistive element and intersecting the first direction, and having a first surface facing the magnetoresistive element; and a magnetically permeable portion made of a ferromagnetic material and provided on at least a portion of the surfaces of the wiring other than the first surface, wherein the wiring is arranged so that an induced magnetic field generated when current is applied is applied to the magnetoresistive element in the first direction.

[0008] The magnetically permeable portion functions as a magnetic collector that collects the induced magnetic field from the wiring, and can increase the strength of the induced magnetic field applied to the magnetoresistive element.

[0009] In the magnetic sensor described above, it may be preferable to provide an insulating layer between the wiring and the magnetically permeable portion. If the magnetically permeable portion has a low resistivity, the amount of current flowing through the magnetically permeable portion increases if an insulating layer is not provided. As a result, the amount of current flowing through the wiring decreases relatively, and the strength of the induced magnetic field decreases.

[0010] When an insulating layer is provided, the insulating layer is preferably a diffusion-suppressing layer that suppresses interdiffusion between the elements constituting the wiring and the elements constituting the magnetically permeable portion. When the insulating layer suppresses interdiffusion between the wiring and the magnetically permeable portion, the phenomenon in which the composition of the wiring and / or the magnetically permeable portion changes over time is unlikely to occur, and the quality stability (functional stability) of the sensor is increased.

[0011] In the magnetic sensor, a magnetic gap may be provided in the magnetic permeable portion. The magnetic permeable portion may function as a magnetic shield that prevents an external magnetic field from being applied to the magnetoresistive element. Even in such a case, the provision of the magnetic gap increases the magnetic resistance of the magnetic permeable portion, making it easier for the external magnetic field to be applied to the magnetoresistive element.

[0012] When providing a magnetic gap, it is preferable that the magnetic gap be provided on a second surface of the wiring that faces the first surface and that extends in a direction perpendicular to the first direction. Even if an external magnetic field is collected in the magnetically permeable portion, the magnetic resistance on the second surface side is high, so that the external magnetic field can be efficiently guided to the first surface side (the side where the magnetoresistive effect element is located).

[0013] In the magnetic sensor described above, a magnetic permeable portion may be provided on at least one of the side surfaces of the wiring, which is the surface facing the first direction. The magnetic permeable portion provided on the side surface functions as a magnetic collector that collects an induced magnetic field from the wiring, as well as a magnetic collector that collects an external magnetic field in the first direction. In particular, when the length of the magnetic permeable portion in the first direction is long, the external magnetic field in the first direction is efficiently collected by the magnetic permeable portion, so that a stronger external magnetic field can be applied to the magnetoresistive element than when no magnetic permeable portion is provided.

[0014] When a magnetic permeable portion is provided on at least a portion of the above-mentioned side surface, if the magnetic permeable portion does not extend onto the second surface, the area on the second surface functions as a magnetic gap, thereby efficiently directing an external magnetic field to the first surface side on which the magnetoresistive effect element is arranged.

[0015] When a magnetic permeable portion is provided on at least a part of the side surface, the end of the magnetic permeable portion on the second direction side facing the magnetoresistive element may have a function of converting the second direction component of the applied external magnetic field into the first direction component and applying it to the magnetoresistive element. In this case, the magnetic sensor has a function of detecting the external magnetic field in the second direction.

[0016] In the magnetic sensor described above, the wiring and the magnetoresistive element may be formed on the same substrate. When the wiring and the magnetoresistive element are formed on the same substrate, the wiring is the same size as the magnetoresistive element, making it difficult to increase the amount of current flowing through the wiring. Even in such a case, if the magnetic sensor has a configuration that strengthens the induced magnetic field from the wiring, as in the magnetic sensor described above, it can effectively achieve purposes such as noise removal.

[0017] In this case, it is advantageous in terms of manufacturing that the first direction is one of the in-plane directions of the substrate and the second direction is the thickness direction of the substrate. [Effects of the Invention]

[0018] According to the present invention, there is provided a magnetic sensor capable of efficiently applying an induced magnetic field from wiring arranged in the vicinity of a magnetoresistive element. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a circuit diagram of a magnetic sensor according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA' in FIG. [Figure 3] 10 is a graph showing the relationship between the efficiency of the bias magnetic field and the width of the magnetically permeable portion as a result of Example 1. [Figure 4] 10 is a graph showing the relationship between the amplification factor of the external magnetic field and the width of the magnetically permeable portion as a result of Example 1. [Figure 5] FIG. 2 is a cross-sectional view illustrating the structure of a magnetic sensor according to Example 2-1. [Figure 6]FIG. 10 is a cross-sectional view illustrating the structure of a magnetic sensor according to Example 2-2. [Figure 7] FIG. 10 is a cross-sectional view illustrating the structure of a magnetic sensor according to Example 2-3. [Figure 8A] FIG. 10 is a cross-sectional view illustrating the structure of a magnetic sensor according to Example 2-6. [Figure 8B] FIG. 10 is a cross-sectional view illustrating a modified example of the magnetic sensor according to Example 2-6. [Figure 9] FIG. 10 is a circuit diagram of a magnetic sensor according to Example 2-7. [Figure 10A] FIG. 10 is a cross-sectional view taken along line BB' in FIG. [Figure 10B] FIG. 10 is a cross-sectional view illustrating a modified example of the magnetic sensor according to Example 2-7. [Figure 11] FIG. 10 is a cross-sectional view illustrating the structure of a magnetic sensor according to an example of a modified example of the embodiment of the present invention. [Figure 12] FIG. 10 is a cross-sectional view illustrating the structure of a magnetic sensor according to another example of a modified example of the embodiment of the present invention. [Figure 13] FIG. 10 is a cross-sectional view illustrating the structure of a magnetic sensor according to another example of a modified example of the embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals, and the description of components that have already been described will be omitted as appropriate.

[0021] FIG. 1 is a circuit diagram of a magnetic sensor according to one embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line A-A' in FIG. 1. As shown in FIG. 1, a magnetic sensor 100 according to one embodiment of the present invention includes magnetoresistive effect elements 10a, 10b, 10c, and 10d (when not distinguishing between them, they will be referred to as magnetoresistive effect elements 10 as appropriate). The four magnetoresistive effect elements 10 may be provided on the same substrate (one chip). In this embodiment, the four magnetoresistive effect elements 10 are provided on the same substrate (not shown), and FIG. 1 is a view of the magnetic sensor 100 as viewed from the stacking surface (front surface) of the substrate in the normal direction of the substrate. That is, in FIG. 1, the Z1 side of the Z1-Z2 direction is the front surface of the substrate, and the Z2 side of the Z1-Z2 direction is the back surface of the substrate. The Z1-Z2 direction is aligned with the stacking direction of the magnetoresistive effect elements 10.

[0022] The magnetic sensor 100 is configured such that a first half-bridge circuit, in which magnetoresistive effect elements 10a and 10b, both of which extend in the Y direction, are connected in series, and a second half-bridge circuit, in which magnetoresistive effect elements 10c and 10d, both of which extend in the Y direction, are connected in series, are connected in parallel between a power supply terminal Vdd, which is a power supply feeding point, and a ground terminal GND.

[0023] The first half-bridge circuit has an output terminal V1 between the magnetoresistive element 10a and the magnetoresistive element 10b. The second half-bridge circuit has an output terminal V2 between the magnetoresistive element 10c and the magnetoresistive element 10d. The magnitude of the external magnetic field applied from the outside as the detection magnetic field H can be quantitatively measured from the potential difference (Va-Vb, midpoint potential difference) between the outputs of these two output terminals V1 and V2.

[0024] The pair of magnetoresistive effect elements 10a and 10b forming the first half-bridge circuit have the magnetization directions of the pinned magnetic layers 11 aligned in the X1-X2 direction (X2 direction) and the X1-X2 direction (X1 direction), respectively, as shown by the white arrows in Fig. 1. The pair of magnetoresistive effect elements 10c and 10d forming the second half-bridge circuit have the magnetization directions of the pinned magnetic layers 11 aligned in the X1-X2 direction (X1 direction) and the X1-X2 direction (X2 direction), respectively, as shown by the white arrows in Fig. 1.

[0025] In the first half-bridge circuit and the second half-bridge circuit, the magnetization directions of the pinned magnetic layers 11 of the magnetoresistive effect elements 10a and 10c on the power supply terminal Vdd side are opposite (anti-parallel). Also, the magnetization directions of the pinned magnetic layers 11 of the magnetoresistive effect elements 10b and 10d on the ground terminal GND side are opposite (anti-parallel). Therefore, the sensitivity axis direction of the magnetoresistive effect element 10 is the X1-X2 direction, which is also referred to as the "first direction" in this specification.

[0026] The four magnetoresistive effect elements 10a to 10d have the same magnetization direction (direction of the bias magnetic field) of the free magnetic layer 12 when no external magnetic field is applied, and are aligned along the Y1-Y2 direction Y2, as indicated by the black arrow in Figure 1.

[0027] With the above-described configuration, the output terminal V1 from the first half-bridge circuit and the output terminal V2 from the second half-bridge circuit change in opposite directions as the magnitude of the detected magnetic field H in the X1-X2 direction changes. This results in a large output as the potential difference between the two output terminals V1 and V2. Therefore, the magnetic sensor 100 can detect the detected magnetic field H with high accuracy. Note that a first or second half-bridge circuit or a magnetoresistance effect element 10 can be used instead of the full-bridge circuit.

[0028] 2, the magnetoresistive element 10a may be, for example, a GMR element (giant magnetoresistive element) or a TMR element (tunneling magnetoresistive element), and includes a pinned magnetic layer 11, a free magnetic layer 12, and an intermediate layer 13 formed between the pinned magnetic layer 11 and the free magnetic layer 12. The resistance value of the magnetoresistive element 10a varies depending on the relative relationship between the magnetization directions of the pinned magnetic layer 11, whose magnetization direction is fixed, and the free magnetic layer 12, whose magnetization direction changes depending on an external magnetic field. The magnetic sensor 100 can measure the direction and strength of the external magnetic field to be measured based on the change in the resistance value of the magnetoresistive element 10a.

[0029] When the magnetoresistive element 10a is a GMR element, the pinned magnetic layer 11 is made of a ferromagnetic layer such as a CoFe alloy (cobalt-iron alloy). The free magnetic layer 12 is made of a soft magnetic material such as a CoFe alloy or a NiFe alloy (nickel-iron alloy) and has a single-layer structure, a laminated structure, a laminated ferrimagnetic structure, or the like. The intermediate layer 13 is a nonmagnetic intermediate layer made of a nonmagnetic material such as Cu.

[0030] A bias magnetic field is applied to the free magnetic layer 12 in a direction perpendicular to the sensitivity axis direction (first direction) to stabilize the output of the magnetic sensor 100. In the magnetic sensor 100 according to this embodiment, the direction of the bias magnetic field is the Y1-Y2 direction, Y2, as shown in FIG. 1. This allows the magnetization direction of the soft magnetic material forming the free magnetic layer 12 to be aligned when no magnetic field is applied.

[0031] As described above, the magnetization direction of the pinned magnetic layer 11 of the magnetoresistive element 10a is pinned in the X1-X2 direction (X2), and the magnetization direction of the free magnetic layer 12 when no magnetic field is applied is in the Y1-Y2 direction (Y2), which is perpendicular to the magnetization direction of the pinned magnetic layer 11. Therefore, the resistance value of the magnetoresistive element 10a changes in the opposite direction depending on whether the direction of the detected magnetic field H is the X1 direction or the X2 direction in the X1-X2 direction. In other words, because the resistance value is an odd function of the detected magnetic field H in the X1-X2 direction, the direction and magnitude of the detected magnetic field H can be continuously measured.

[0032] The magnetoresistive effect element 10a may be a TMR element instead of the GMR element described above. In this case, the intermediate layer 13 is an insulating barrier layer made of MgO, Al2O3, titanium oxide, or the like.

[0033] The magnetoresistive effect elements 10b to 10d have the same basic structure as the magnetoresistive effect element 10a. From the viewpoint of improving measurement accuracy, it is preferable that the magnetoresistive effect elements 10a to 10d are manufactured on the same substrate using a common manufacturing process.

[0034] 1, a magnetic field generating unit MG1 is provided on the Z2 side of the magnetoresistive effect elements 10a and 10b in the Z1-Z2 direction, and a magnetic field generating unit MG2 is provided on the Z2 side of the magnetoresistive effect elements 10c and 10d in the Z1-Z2 direction. In the magnetic sensor 100, the magnetic field generating unit MG1 and the magnetic field generating unit MG2 have the same structure.

[0035] 2, the magnetic field generating unit MG1 is located on the Z2 side of the magnetoresistive effect element 10a in the Z1-Z2 direction, and has wiring 20 extending in the Y1-Y2 direction. That is, the wiring 20 is located on the Z1-Z2 side of the magnetoresistive effect element 10a, which is a second direction intersecting the first direction (X1-X2 direction), and has a first surface 21 facing the magnetoresistive effect element 10a and facing the Z1 side in the Z1-Z2 direction.

[0036] In the magnetic sensor 100 according to this embodiment, the wiring 20 is formed so as to be embedded in a substrate (not shown) together with the magnetoresistive effect element 10a. The material constituting the wiring 20 is not particularly limited as long as it is a conductor, and is preferably a material based on a nonmagnetic element such as copper or aluminum. Note that it may be advantageous in manufacturing if the first direction is one of the in-plane directions of the substrate and the second direction is the thickness direction of the substrate. The separation distance between the wiring 20 and the magnetoresistive effect element 10a is set so that a predetermined induced magnetic field from the wiring 20 is applied to the magnetoresistive effect element 10a. In this embodiment, since the magnetoresistive effect element 10a is formed by a film formation process on the substrate in which the wiring 20 is embedded, the separation distance is set, for example, on the order of microns or submicrons.

[0037] By passing a current through the wiring 20, an induced magnetic field along the sensitivity axis direction (first direction, X1-X2 direction) is applied as a bias magnetic field to the free magnetic layer 12 of the magnetoresistive element 10a. In the magnetic sensor 100 according to this embodiment, the width (length in the X1-X2 direction) and height (length in the Z1-Z2 direction) of the wiring 20 are approximately several μm. Since the wiring 20 is embedded in the substrate as described above, the amount of current that can be passed through the wiring 20 is limited due to the efficiency of Joule heat dissipation. Therefore, there is a limit to how much current can be passed through the wiring 20 to strengthen the induced magnetic field applied to the free magnetic layer 12. In particular, when a magnetic field having a strength equivalent to the saturation magnetic field of the magnetoresistive element 10a is applied as a bias magnetic field, the fact that the amount of current passing through the wiring 20 has a substantial upper limit easily becomes an issue.

[0038] Therefore, the magnetic field generating unit MG1 of the magnetic sensor 100 includes a magnetic permeable portion 30 made of a ferromagnetic material and provided on at least a portion of the surfaces of the wiring 20 other than the first surface 21. In the magnetic sensor 100 according to this embodiment, the cross-sectional shape of the wiring 20 in the XY plane is rectangular, and therefore the surfaces of the wiring 20 other than the first surface 21 are a second surface 22 facing the first surface 21 in the second direction and two surfaces (a third surface 23 and a fourth surface 24) facing the first direction (X1-X2 direction). As shown in FIG. 1 , the magnetic permeable portion 30 includes a first magnetic permeable portion 31 provided on the third surface 23 and a second magnetic permeable portion 32 provided on the fourth surface 24 among these surfaces.

[0039] The magnetic permeable portion 30 (the first magnetic permeable portion 31 and the second magnetic permeable portion 32) collects the induced magnetic field from the wiring 20 and can efficiently apply a bias magnetic field along the first direction (X1-X2 direction) to the free magnetic layer 12 of the magnetoresistive effect element 10a. In particular, even when the bias magnetic field is required to have a strength equivalent to the saturation magnetic field of the magnetoresistive effect element 10a, the magnetic sensor 100 according to this embodiment can apply a magnetic field of appropriate strength by the induced magnetic field of the wiring 20.

[0040] The material of the magnetically permeable portion 30 is not particularly limited as long as it is a ferromagnetic material. A specific example is a soft magnetic material such as permalloy. The distance between the magnetically permeable portion 30 and the wiring 20 is not limited. For example, it may be a few micrometers in size, which is the same as the size (height and width) of the wiring 20.

[0041] The length (first direction length) of the magnetic permeable portion 30 (first magnetic permeable portion 31 and second magnetic permeable portion 32) in the first direction (X1-X2 direction) is appropriately set depending on the strength of the bias magnetic field to be applied to the free magnetic layer 12. If the first direction length is excessively short, the magnetic permeable portion 30 will have difficulty in properly performing the function of collecting the induced magnetic field. Furthermore, if the first direction length is excessively long, the induced magnetic field will be dispersed inside the magnetic permeable portion 30, making it difficult to increase the strength of the induced magnetic field applied to the free magnetic layer 12 as a bias magnetic field along the first direction. On the other hand, a magnetic permeable portion 30 with a long first direction length may effectively function as a magnetic collector of an external magnetic field in the first direction. Therefore, it is preferable to set the first direction length from the viewpoint of the ratio between the strength of the induced magnetic field applied to the free magnetic layer 12 and the strength of the external magnetic field.

[0042] The magnetic field generating unit MG1 of the magnetic sensor 100 according to this embodiment has an insulating layer 40 between the wiring 20 and the magnetically permeable unit 30. When the magnetically permeable unit 30 is made of a metallic material such as permalloy, its resistivity is relatively low. Therefore, if the insulating layer 40 is not provided, a current will also flow through the magnetically permeable unit 30 when a current is applied. As a result, the amount of current flowing through the wiring 20 will decrease relatively, and the strength of the induced magnetic field from the wiring 20 will decrease.

[0043] The insulating layer 40 may be made of any material and have any thickness as long as it can prevent the current flowing through the wiring 20 from flowing to the magnetically permeable portion 30. The insulating layer 40 is preferably a diffusion-suppressing layer that suppresses mutual diffusion between the elements constituting the wiring 20 and the elements constituting the magnetically permeable portion 30. When the insulating layer 40 suppresses mutual diffusion between the wiring 20 and the magnetically permeable portion 30, the compositions of the two are less likely to change over time, thereby increasing the quality stability (functional stability) of the magnetic sensor 100. From the viewpoint of a diffusion-suppressing layer, specific examples of the material constituting the insulating layer 40 include silica (SiO2) and alumina (Al2O3). Examples of the material include oxide-based materials, silicon nitride (Si3N4), aluminum nitride (AlN), and other nitride-based materials, and the thickness thereof may preferably be 50 nm or more.

[0044] The above-described embodiments have been described to facilitate understanding of the present invention, and are not intended to limit the present invention. Therefore, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention. [Example]

[0045] The present invention will be described in more detail below using simulated examples, but the present invention is not limited thereto. The magnetic sensors according to the examples share the same circuit configuration (full-bridge circuit) as the magnetic sensor 100 according to the above-described embodiment, and include four magnetoresistance effect elements 10a to 10d. The differences between the examples are in the structures of the magnetic field generating units MG1 and MG2. Therefore, in the following examples (excluding Examples 2-7), the structures will be described using cross-sectional views similar to the cross-sectional view of the magnetic sensor 100 taken along line A-A'.

[0046] Example 1 The magnetic sensor 100 according to the first embodiment has the cross-sectional structure shown in Fig. 2. That is, the magnetic field generating unit MG1 is located on the Z2 side of the magnetoresistive element 10a in the Z1-Z2 direction, and has wiring 20 extending in the Y1-Y2 direction. Of the surfaces of the wiring 20, a first magnetic permeable portion 31 and a second magnetic permeable portion 32 are provided on a third surface 23 and a fourth surface 24 facing the first direction (X1-X2 direction), and no magnetic permeable portion 30 is provided on a first surface 21 facing the magnetoresistive element 10a or a second surface 22 facing the first surface 21. An insulating layer 40 is provided between the first magnetic permeable portion 31 and the second magnetic permeable portion 32 and the wiring 20.

[0047] In Example 1, the length of the magnetoresistive element 10a in the X1-X2 direction (element width Ws) is 1.0 μm, and the length of the magnetoresistive element 10a in the Y1-Y2 direction (element length) is 64 μm. The length of the wiring 20 in the X1-X2 direction (wiring width Wp) is 2.0 μm, the length of the wiring 20 in the Z1-Z2 direction (wiring height Hp) is 1.5 μm, and the length of the wiring 20 in the Y1-Y2 direction (wiring length) is 80 μm. The distance between the magnetoresistive element 10a and the wiring 20 is 0.25 μm, and the thickness of the insulating layer 40 is 0.5 μm.

[0048] The length in the Y1-Y2 direction of the first magnetic permeable portion 31 and the second magnetic permeable portion 32 (magnetic permeable portion length) is 80 μm, which is equal to the wiring length, and the length in the X1-X2 direction of the first magnetic permeable portion 31 (first magnetic permeable portion width Wm1) and the length in the X1-X2 direction of the second magnetic permeable portion 32 (second magnetic permeable portion width Wm2) are equal lengths and were changed within the range of 0.2 μm to 16 μm. Hereinafter, the widths of these magnetic permeable portions will be abbreviated as "magnetic permeable portion widths."

[0049] The current flowing through the wiring 20 is 1 mA, and the strength of the external magnetic field applied in the first direction (X1-X2 direction) is 1 mT.

[0050] The results of simulating the efficiency of the bias magnetic field (bias magnetic field due to induced magnetic field / current value, unit: mT / mA) and the amplification factor of the external magnetic field (detected magnetic field H / applied external magnetic field, unit: mT / mT) applied to the magnetoresistive effect element 10a as a saturation magnetic field under the above conditions are shown in Table 1 and Figures 3 and 4.

[0051] [Table 1]

[0052] As shown in FIG. 3, the relationship between the efficiency of the bias magnetic field and the magnetic permeable portion width (first magnetic permeable portion width Wm1, second magnetic permeable portion width Wm2) showed a maximum value at a magnetic permeable portion width of approximately 2 μm. Up to a magnetic permeable portion width of approximately 2 μm, the provision of the magnetic permeable portion 30 efficiently collects the induced magnetic field from the wiring 20 at the magnetic permeable portion 30, and the collected magnetic field is applied to the magnetoresistive effect element 10a, improving the efficiency of the bias magnetic field. On the other hand, when the magnetic permeable portion width is greater than approximately 2 μm, the efficiency of the bias magnetic field decreases. At a magnetic permeable portion width of 15 μm or greater, the efficiency becomes equivalent to when the magnetic permeable portion 30 is not provided (Example 2-1, described later). This is thought to be because, when the magnetic permeable portion width is excessively large, the induced magnetic field is dispersed within the magnetic permeable portion 30, reducing the magnetic collection function of the magnetic permeable portion 30.

[0053] On the other hand, the relationship between the amplification factor of the external magnetic field and the magnetic permeable portion width was approximately linear, as shown in Fig. 4. That is, it was confirmed that the magnetic permeable portion 30 (first magnetic permeable portion 31, second magnetic permeable portion 32) according to Example 1 has the function of collecting the external magnetic field in the first direction and applying it to the magnetoresistance effect element 10a, and that this function becomes stronger as the magnetic permeable portion width becomes larger. Furthermore, since the graph shown in Fig. 4 shows that the amplification factor is 1 when the magnetic permeable portion width is 1 µm, it was also confirmed that in the magnetic permeable portion 30 (first magnetic permeable portion 31, second magnetic permeable portion 32) according to Example 1, the shielding function of blocking the external magnetic field in the first direction from being applied to the magnetoresistance effect element 10a does not become apparent if the magnetic permeable portion width is 1 µm or more.

[0054] Example 2 In Example 1, the influence of the magnetic permeable portion width on the efficiency of the bias magnetic field and the amplification factor of the external magnetic field was evaluated, but in this example, the influence when the shape of the magnetic permeable portion 30 was further changed was evaluated. Simulations were performed for multiple magnetic field generating units MG1 with magnetic permeable portions 30 having different shapes.

[0055] Example 2-1 5, the magnetic field generating unit MG1 according to Example 2-1 has a first magnetic permeable portion width Wm1 and a second magnetic permeable portion width Wm2 both of which are 0 μm, and is not provided with an insulating layer 40. The shape of the wiring 20 is the same as in Example 1 (wiring width Wp: 2.0 μm, wiring height Hp: 1.5 μm, wiring length: 64 μm), and the separation distance between the magnetoresistive effect element 10a and the wiring 20 is also the same as in Example 1 (0.25 μm). The direction in which an external magnetic field is applied is the first direction (X1-X2 direction).

[0056] (Example 2-2) 6, the magnetic field generating unit MG1 according to Example 2-2 has magnetic permeable portions 30 with a thickness of 0.5 μm provided on the second surface 22, the third surface 23, and the fourth surface 24 of the wiring 20 having the same shape as that of Example 1. That is, the magnetic permeable portion 30 of the magnetic field generating unit MG1 according to Example 2-2 has a first magnetic permeable portion 31 with a first magnetic permeable portion width Wm1 of 0.5 μm, a second magnetic permeable portion 32 with a second magnetic permeable portion width Wm2 of 0.5 μm, and a third magnetic permeable portion 33 with a magnetic permeable portion height Hm of 0.5 μm, and has a U-shaped cross section as a whole. The direction in which the external magnetic field is applied is the first direction (X1-X2 direction).

[0057] (Example 2-3) 7, the magnetic field generating unit MG1 according to Example 2-3 has the same structure as that of Example 2-2, and has an insulating layer 40 with a thickness of 0.1 μm between the wiring 20 and the magnetically permeable portion 30. The direction in which the external magnetic field is applied is the first direction (X1-X2 direction).

[0058] (Examples 2-4) 2, the width of the first magnetic permeable portion 31 (first magnetic permeable portion width Wm1) and the width of the second magnetic permeable portion 32 (second magnetic permeable portion width Wm2) are both 0.5 μm. The direction in which the external magnetic field is applied is the first direction (X1-X2 direction).

[0059] (Examples 2-5) 2, the width of the first magnetic permeable portion 31 (first magnetic permeable portion width Wm1) and the width of the second magnetic permeable portion 32 (second magnetic permeable portion width Wm2) are both 16 μm. The direction in which the external magnetic field is applied is the first direction (X1-X2 direction).

[0060] (Examples 2-6) 8A , the magnetic field generating unit MG1 according to Example 2-6 has a wiring 20 having the same shape as that of Example 1, and similarly to Example 2-5, a first magnetic permeable portion 31 having a first magnetic permeable portion width Wm1 of 16 μm is provided on the third surface 23 and a second magnetic permeable portion 32 having a second magnetic permeable portion width Wm2 of 16 μm is provided on the fourth surface 24. In Example 2-6, the first magnetic permeable portion 31 has a first extending portion 331 extending onto the second surface 22 of the wiring 20, and the extending width We1 is 0.6 μm. The second magnetic permeable portion 32 also has a second extending portion 332 extending onto the second surface 22 of the wiring 20, and the extending width We2 is 0.6 μm. In other words, the magnetic field generating unit MG1 according to Example 2-6 has a third magnetic permeable part 33 having a magnetic gap G with a width (gap width Wg) of 1.0 μm on the second surface 22 of the wiring 20. The direction in which the external magnetic field is applied is the first direction (X1-X2 direction).

[0061] (Examples 2-7) The magnetic sensor 101 according to Examples 2-7 is different from the magnetic sensors 100 according to the other Examples in that it measures an external magnetic field in the second direction (Z1-Z2 direction). As shown in FIG. 9, its circuit configuration is the same as that of the magnetic sensor 100 shown in FIG. 1, and the direction (sensitivity axis direction) of the detection magnetic field H of the four magnetoresistive effect elements 10a to 10d is along the first direction (X1-X2 direction). A magnetic field generating unit MG is provided on the Z2 side of the four magnetoresistive effect elements 10a to 10d in the second direction (Z1-Z2 direction). The arrangement pitch P between the magnetoresistive effect elements 10a and 10c arranged adjacent to each other in the first direction (X1-X2 direction) is 12.2 μm.

[0062] Fig. 10A is a cross-sectional view taken along line BB' in Fig. 9. As shown in Fig. 10A, a wiring 202 having a first surface 212 facing the magnetoresistive effect element 10a is provided on the Z2 side of the magnetoresistive effect element 10a in the second direction (Z1-Z2 direction), and a wiring 201 having a first surface 211 facing the magnetoresistive effect element 10c is provided on the Z2 side of the magnetoresistive effect element 10c in the second direction (Z1-Z2 direction).

[0063] Insulating layers 40 are provided on the second surface 221 and the fourth surface 241 of the wiring 201 and the second surface 222 and the third surface 232 of the wiring 202, and these insulating layers 40 are continuous. Between the wirings 201 and 202 in the first direction (X1-X2 direction), magnetically permeable portions 30 are provided to fill the gap, and the magnetically permeable portion width Wm is 10 μm. In addition, magnetically permeable portions 30 are also provided on the Z2 side of each of the wirings 201 and 202 in the second direction (Z1-Z2 direction), and the length (magnetically permeable portion height Hm) from the second surfaces 221, 222 in the second direction (Z1-Z2 direction) is 10 μm.

[0064] The efficiency of the bias magnetic field and the amplification factor of the external magnetic field were determined by performing a simulation similar to that of Example 1 for each Example. The results are shown in Table 2.

[0065] [Table 2]

[0066] As shown in Table 2, when the magnetic permeable portion 30 was provided so as to cover all but the first surface 21 (Example 2-2), the bias magnetic field increased significantly (2.8 times) compared to when the magnetic permeable portion 30 was not provided (Example 2-1), but the detection magnetic field H attenuated (0.22 times). When the insulating layer 40 was provided between the magnetic permeable portion 30 and the wiring 20 (Example 2-3), the same results as in Example 2-2 were obtained.

[0067] In the magnetic field generating units MG1 of Examples 2-2 and 2-3, the magnetic permeable portions 30 are provided so as to cover the second surface 22, the third surface 23, and the fourth surface 24. Therefore, it is believed that the induced magnetic field of the wiring 20 is efficiently collected by the magnetic permeable portions 30 and applied to the magnetoresistive effect element 10a. On the other hand, in the magnetic field generating units MG1 of these Examples, the magnetic permeable portions 30 have a U-shaped cross section. Therefore, the external magnetic field in the first direction (X1-X2 direction) is collected to one side of the magnetic permeable portion 30 (for example, the first magnetic permeable portion 31), and the collected magnetic flux flows through the third magnetic permeable portion 33 to the other side of the magnetic permeable portion 30 (the second magnetic permeable portion 32). Therefore, it is believed that the strength of the detected magnetic field H detected by the magnetoresistive effect element 10a is reduced. In other words, the magnetic field generating units MG1 of Examples 2-2 and 2-3 exhibited results that demonstrated the shielding function of the external magnetic field.

[0068] When the magnetic permeable portion 30 was not provided on the second surface 22 (Example 2-4), the bias magnetic field was attenuated (by about half) compared to Example 2-3, but the degree of attenuation of the detection magnetic field H was less, resulting in about 90% of that when the magnetic permeable portion 30 was not provided (Example 2-1). The magnetic field generating unit MG1 of Example 2-4 does not have the magnetic permeable portion 30 on the second surface 22. In other words, the magnetic field generating unit MG1 of Example 2-4 does not have the third magnetic permeable portion 33 compared to the magnetic field generating unit MG1 of Example 2-3. Therefore, the induced magnetic field around the Y1-Y2 direction of the wiring 20 is less easily collected by the magnetic permeable portion 30 compared to the magnetic field generating unit MG1 of Example 2-3. This is thought to be the reason for the relative decrease in the strength of the bias magnetic field.

[0069] On the other hand, the magnetic field generating unit MG1 of Example 2-4 does not have the third magnetic permeable portion 33 in comparison with the magnetic field generating unit MG1 of Example 2-3, and therefore, when the magnetic flux of the external magnetic field collected at one side of the magnetic permeable portion 30 (for example, the first magnetic permeable portion 31) heads toward the other side of the magnetic permeable portion 30 (the second magnetic permeable portion 32), there is substantially no difference between passing through the first surface 21 side and passing through the second surface 22 side. For this reason, compared to the magnetic field generating unit MG1 of Example 2-3, which had the third magnetic permeable portion 33 and was therefore more advantageous for passing through the second surface 22 side, the amount of magnetic flux passing through the first surface 21 side is increased, and as a result, it is thought that the strength of the detected magnetic field H in the magnetoresistance effect element 10a is increased.

[0070] The magnetic field generating unit MG1 of Example 2-5 has a larger width of the first magnetic permeable portion 31 (first magnetic permeable portion width Wm1) and a larger width of the second magnetic permeable portion 32 (second magnetic permeable portion width Wm2) than the magnetic field generating unit MG1 of Example 2-4. In this case, it has been confirmed that the amplification factor of the external magnetic field is larger in Example 1, and the amplification factor of the external magnetic field in Example 2-5 is also larger than that in Example 2-4 (approximately 3.8 times).

[0071] In comparison with the magnetic field generating unit MG1 of Example 2-5, the magnetic field generating unit MG1 of Example 2-6 has a magnetic permeable portion 30 extending toward the second surface 22 (first extending portion 331, second extending portion 332). These extending portions correspond to a third magnetic permeable portion 33 having a magnetic gap G with a width Wg of 1.0 μm on the second surface 22. In the magnetic field generating unit MG1 of Example 2-6, due to the presence of this magnetic gap G, the efficiency of the bias magnetic field is lower than when the magnetic gap G is not provided in the third magnetic permeable portion 33 (Example 2-3, 0.45 mT / mA). However, the efficiency is higher (0.27 mT / mA) than when the third magnetic permeable portion 33 is not provided on the second surface 22 (Example 2-4 or Example 2-5, 0.22 mT / mA), in other words, when a magnetic gap G with a width Wg of 2.0 μm is provided on the second surface 22. On the other hand, the amplification factor of the external magnetic field was higher than when no magnetic gap G was provided in the third magnetic permeable portion 33 (Example 2-3, 0.22 mT / mT), but lower (2.28 mT / mT) than when no third magnetic permeable portion 33 was provided on the second surface 22 (Example 2-4 and Example 2-5, 3.39 mT / mT).

[0072] In the magnetic field generating unit MG of Example 2-7, the magnetic permeable portion 30 is provided on one of the surfaces facing the first direction (the fourth surface 241 for the wiring 201, and the third surface 232 for the wiring 202) and the second surface 221 or the second surface 222. Therefore, the induced magnetic field of the wiring 201, 202 is appropriately collected, and the efficiency of the bias magnetic field is equivalent to that of Example 2-6. Unlike the other examples, Example 2-7 has a structure for detecting an external magnetic field in the second direction (Z1-Z2 direction). Specifically, the magnetic flux of the external magnetic field passing through the magnetic permeable portion 30 toward the Z1 side in the Z1-Z2 direction changes direction in the first direction (X1-X2 direction) when emitted from the end of the magnetic permeable portion 30 on the Z1 side of the second direction (Z1-Z2 direction). This component is detected by the magnetoresistance effect element 10a and the magnetoresistance effect element 10c, each having a sensitivity axis in the first direction. Therefore, the amplification factor of the external magnetic field cannot be compared with other examples, but results were obtained showing that an external magnetic field in a direction perpendicular to the sensitivity axis direction (first direction) of the magnetoresistive effect element 10a and the magnetoresistive effect element 10c is detected with an intensity not significantly different (approximately 80%) from that when the magnetic permeable portion 30 is not provided (Example 2-1).

[0073] Modified examples of the magnetic sensor according to this embodiment will be described below. FIG. 11 is a diagram illustrating an example of a modified example of the magnetic sensor according to this embodiment. Like FIG. 2, FIG. 11 is a cross-sectional view including a cross section of one magnetoresistive element 10a and a corresponding magnetic field generating unit MG1. As illustrated in FIG. 11, a magnetic sensor 102 according to this modification, compared to the magnetic sensor 100 illustrated in FIG. 1, has a wiring 20A having the same shape as the wiring 20 on the Z1 side of the magnetoresistive element 10a in the Z1-Z2 direction (second direction). Currents flow in opposite directions through the wiring 20 and the wiring 20A, thereby applying an induced magnetic field of the same direction to the free magnetic layer 12 of the magnetoresistive element 10a. In FIG. 11, a current flows through the wiring 20 on the Y1 side in the Y1-Y2 direction, and a current flows through the wiring 20A on the Y2 side in the Y1-Y2 direction, thereby applying an induced magnetic field to the free magnetic layer 12 of the magnetoresistive element 10a in the X2 direction. This direction is equal to the magnetization direction of the pinned magnetic layer 11 of the magnetoresistive element 10a.

[0074] Fig. 12 is a diagram showing another example of a modified example of the magnetic sensor according to the present embodiment. Similar to Fig. 2, Fig. 12 is a cross-sectional view including a cross section of one magnetoresistive effect element 10a and the corresponding magnetic field generating unit MG1. In the magnetic sensor 103 according to this example, the magnetoresistive effect element 10a has three magnetoresistive effect elements 10a1, 10a2, and 10a3, and the pinned magnetic layers 11 of all of these elements are magnetized in the same direction (X1-X2 direction, X2 direction) (white arrows).

[0075] On both sides of the second direction (Z1-Z2 direction) of each of the magnetoresistive effect elements 10a1, 10a2, and 10a3, magnetic field generating units MG0 having the same structure as the magnetic field generating unit MG1 of Example 2-4 are provided. Therefore, in the magnetic sensor 103 according to this example, the magnetic field generating unit MG1 has six magnetic field generating units MG0. The wiring 20 of the three magnetic field generating units MG0 provided on the Z1 side of the second direction (Z1-Z2 direction) is arranged along the first direction (X1-X2 direction) to form parallel coils, and current flows in all of them on the Y2 side in the Y1-Y2 direction. The wiring 20 of the three magnetic field generating units MG0 provided on the Z2 side of the second direction (Z1-Z2 direction) is also arranged along the first direction (X1-X2 direction) to form parallel coils, and current flows in all of them on the Y1 side in the Y1-Y2 direction (Y1 side). As a result, the induced magnetic field of the wiring 20 is applied in the direction along the magnetization direction of the pinned magnetic layer 11 to all of the three magnetoresistance effect elements 10a1, 10a2, and 10a3.

[0076] Fig. 13 is a diagram showing another example of a modified example of the magnetic sensor according to the present embodiment. Similar to Fig. 2, Fig. 13 is a cross-sectional view including a cross section of one magnetoresistive effect element 10a and the corresponding magnetic field generating unit MG1. In the magnetic sensor 104 according to this example, similar to the magnetic sensor 103, the magnetoresistive effect element 10a has three magnetoresistive effect elements 10a1, 10a2, and 10a3, and the pinned magnetic layers 11 of all of these elements are magnetized in the same direction (X1-X2 direction, X2 direction) (white arrows).

[0077] On both sides of magnetoresistive effect elements 10a1, 10a2, and 10a3 in the second direction (Z1-Z2 direction), three wires 201, 202, and 203 separated from each other by insulating layers 40 are arranged in the first direction (X1-X2 direction), and magnetic field generating unit MG0 is disposed around them, with magnetic permeable portion 30. Wire 201 has a first surface 21 facing magnetoresistive effect element 10a1 in the second direction, wire 202 has a first surface 21 facing magnetoresistive effect element 10a2 in the second direction, and wire 203 has a first surface 21 facing magnetoresistive effect element 10a3 in the second direction.

[0078] None of the magnetic permeable portions 30 of the magnetic field generating unit MG0 is provided on the first surface 21 of the wirings 201, 202, and 203, and a magnetic gap G is provided on the second surface 22 side of the wiring 202. A current flows in the Y1-Y2 direction (Y2 side) through the wirings 201, 202, and 203 of the magnetic field generating unit MG0 provided on the Z1 side of the second direction (Z1-Z2 direction). A current flows in the Y1-Y2 direction (Y1 side) through the wirings 201, 202, and 203 of the magnetic field generating unit MG0 provided on the Z2 side of the second direction (Z1-Z2 direction). As a result, an induced magnetic field of the wiring 20 is applied to each of the three magnetoresistive effect elements 10a1, 10a2, and 10a3 in a direction along the magnetization direction of the pinned magnetic layer 11.

[0079] FIG. 8B is a cross-sectional view illustrating a modified example of the magnetic sensor according to Example 2-6. FIG. 10B is a cross-sectional view illustrating a modified example of the magnetic sensor according to Example 2-7. In FIGS. 8A and 10A, the magnetoresistive effect element 10a is located closer to the front surface of the substrate (toward the Z1 side in the Z1-Z2 direction) than the magnetic field generating unit MG1 (FIG. 8A) or the magnetic field generating unit MG (FIG. 10A). However, the positional relationship between the magnetoresistive effect element 10a and the magnetic field generating unit MG1 (magnetic field generating unit MG) is not limited to this. From the viewpoint of ease of manufacture, it may be preferable that the magnetic field generating unit MG1 (magnetic field generating unit MG) is located closer to the front surface of the substrate (toward the Z1 side in the Z1-Z2 direction) than the magnetoresistive effect element 10a, as in the magnetic sensor 100A shown in FIG. 8B and the magnetic sensor 101A shown in FIG. 10B. In the magnetic sensor 100A and the magnetic sensor 101A, the first magnetically permeable portion 31, the second magnetically permeable portion 32, the third magnetically permeable portion 33, and the magnetically permeable portion 30 are formed by a plating process. [Explanation of symbols]

[0080] 100, 100A, 101, 101A, 102, 103, 104: Magnetic sensors 10, 10a, 10a1, 10a2, 10a3, 10b, 10c, 10d: magnetoresistive effect elements 11: Fixed magnetic layer 12: Free magnetic layer 13: Middle class 20: Wiring 20A: Wiring 21, 211, 212: Front page 22, 221, 222: 2nd side 23, 232: 3rd page 24, 241: 4th side 30: Permeable part 31: 1st permeable part 32:Second magnetically permeable part 33: 3rd permeable part 40: Insulating layer 201, 202, 203: Wiring 331: 1st extension part 332:Second extension part G: Magnetic gap GND: Ground terminal H: Detected magnetic field Hm: Magnetic permeable part height Hp: Wiring height MG, MG0, MG1, MG2: Magnetic field generating unit P: Array pitch V1, V2: Output terminal Vdd: Power supply terminal We1, We2: Extension width Wm: Width of permeable part Wm1: 1st permeable part width Wm2: 2nd magnetically permeable part width Wp: Wiring width Ws: Element width Wg: Gap width

Claims

1. a magnetoresistive element having a pinned magnetic layer, a free magnetic layer, and an intermediate layer formed between the pinned magnetic layer and the free magnetic layer, the magnetoresistive element having a sensitivity axis in a first direction; a wiring line positioned in a second direction intersecting the first direction along the stacking direction of the magnetoresistive element, the wiring line having a first surface facing the magnetoresistive element; a magnetically permeable portion made of a ferromagnetic material and provided on at least a part of a surface other than the first surface among the surfaces of the wiring; Equipped with the wiring is arranged so that an induced magnetic field generated when a current is applied is applied to the magnetoresistive element in the first direction; An insulating layer is provided between the wiring and the magnetically permeable portion. A magnetic sensor characterized by:

2. 2. The magnetic sensor according to claim 1, wherein the insulating layer is a diffusion suppressing layer that suppresses interdiffusion between elements constituting the wiring and elements constituting the magnetically permeable portion.

3. A magnetoresistive effect element having a fixed magnetic layer, a free magnetic layer, and an intermediate layer formed between the fixed magnetic layer and the free magnetic layer, and having a sensitivity axis in a first direction; a wiring line positioned in a second direction intersecting the first direction along the stacking direction of the magnetoresistive element, the wiring line having a first surface facing the magnetoresistive element; a magnetically permeable portion made of a ferromagnetic material and provided on at least a part of a surface other than the first surface among the surfaces of the wiring; Equipped with the wiring is arranged so that an induced magnetic field generated when a current is applied is applied to the magnetoresistive element in the first direction; A magnetic gap is provided in the magnetically permeable portion. A magnetic sensor characterized by:

4. The magnetic sensor according to claim 3 , wherein the magnetic gap is provided on a second surface of the wiring that faces the first surface and extends along a direction perpendicular to the first direction.

5. A magnetoresistive effect element having a fixed magnetic layer, a free magnetic layer, and an intermediate layer formed between the fixed magnetic layer and the free magnetic layer, and having a sensitivity axis in a first direction; a wiring line positioned in a second direction intersecting the first direction along the stacking direction of the magnetoresistive element, the wiring line having a first surface facing the magnetoresistive element; a magnetically permeable portion made of a ferromagnetic material and provided on at least a part of a surface other than the first surface among the surfaces of the wiring; Equipped with the wiring is arranged so that an induced magnetic field generated when a current is applied is applied to the magnetoresistive element in the first direction; The magnetic permeable portion is provided on at least one of the side surfaces of the wiring, which is a surface facing the first direction. A magnetic sensor characterized by:

6. The magnetic sensor according to claim 5 , wherein the magnetically permeable portion does not extend onto a second surface of the wiring that faces the first surface.

7. 7. The magnetic sensor according to claim 6, wherein the end of the magnetically permeable portion on the second direction side that faces the magnetoresistive element converts the second direction component of the applied external magnetic field into the first direction and applies it to the magnetoresistive element.

8. 6. The magnetic sensor according to claim 1, wherein the wiring and the magnetoresistive element are formed on the same substrate.

9. The magnetic sensor according to claim 8 , wherein the first direction is one of the in-plane directions of the substrate, and the second direction is a thickness direction of the substrate.

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