JP2009300150A - Magnetic sensor and magnetic sensor module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic sensor and a magnetic sensor module, for efficiently improving a magnetic shield effect in a direction perpendicular to its sensitive axis especially. <P>SOLUTION: The magnetic sensor includes magnetoresistive effective elements 2, 3, and the magnetoresistive effective elements 2, 3 have an element part 12 which brings out the magnetoresistive effect, and a soft magnetic material 18 is disposed on both sides of the element part 12 in the sensitive axis direction (Y-direction). Both the side ends 18b of the soft magnetic material 18 in the direction (X-direction) perpendicular to the sensitive axis direction, are positioned so as to elongate rather than the element part 12 in the perpendicular direction. The width dimension of both the side ends 18b is large in comparison with the width dimension of the soft magnetic material 18 except both of the side ends. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a magnetic sensor and a magnetic sensor module using a magnetoresistive effect element used as, for example, a geomagnetic sensor.

  A magnetic sensor using a magnetoresistive effect element can be used as a geomagnetic sensor that detects geomagnetism incorporated in a portable device such as a mobile phone. The magnetoresistive element varies in electric resistance value with respect to the magnetic field from the sensitivity axis direction.

  In the invention described in the following Patent Document 1, a plurality of strip-like magnetoresistive films are arranged in parallel to each other, and end portions of each magnetoresistive element are connected by a permanent magnet film to form a zigzag folded shape. A sensor is disclosed.

  The geomagnetic sensor needs to detect magnetism by splitting it into two or three axes, so the magnetic sensor that detects the strength of the magnetic field of each axis is not sensitive to the other axes. There is a need to.

However, Patent Document 1 does not recognize the conventional problem with respect to the above-described geomagnetic sensor, and naturally does not show means for solving it.
JP 2005-183614 A

  Therefore, the present invention is for solving the above-described conventional problems, and in particular, a magnetic sensor and a magnetic sensor module capable of effectively improving the magnetic shield effect in a direction orthogonal to the sensitivity axis direction. The purpose is to provide.

The present invention is a magnetic sensor comprising a magnetoresistive effect element having a predetermined sensitivity axis,
The magnetoresistive effect element includes an element portion that exhibits a magnetoresistive effect, and a soft magnetic material,
The element part and the soft magnetic body are arranged in a non-contact manner in the order of the soft magnetic body, the element part, and the soft magnetic body in the direction of the sensitivity axis,
Both end portions of the soft magnetic body are at positions extending in the orthogonal direction from the element portion, and the width dimension of the both end portions is larger than the width dimension of the soft magnetic body excluding the both end portions. It is characterized by.

  As a result, a disturbance magnetic field from the direction orthogonal to the sensitivity axis can be easily drawn into the inside of the soft magnetic body from both end portions, and the magnetic shield effect can be effectively improved.

  In the present invention, it is preferable that a tapered surface in which the width dimension is gradually increased is formed in the both end portions of the soft magnetic body in a direction away from the element portion. Thereby, the magnetic shielding effect can be improved more effectively.

  Further, in the present invention, the both side end portions of the soft magnetic material are formed with a width transition region formed by the tapered surface and a maximum width of the width transition region outside the width transition region in the orthogonal direction. It is preferable that the fixed width region is formed. Thereby, the magnetic shielding effect can be improved more effectively.

In the present invention, a plurality of the element portions are arranged at intervals in the sensitivity axis direction, and the end portions of each element portion are electrically connected and formed in a meander shape,
It is preferable that the soft magnetic body is disposed on both sides in the sensitivity axis direction of each element portion by providing the soft magnetic body between the element portions and outside the meander shape.

  Further, in the present invention, a plurality of magnetoresistive effect elements formed from the element portions provided with the soft magnetic material on both sides are arranged in the direction perpendicular to the sensitivity axis so that each magnetoresistive effect element itself has a magnetoresistive effect other than itself. A magnetic sensor can be formed without affecting the element.

  A magnetic sensor module according to the present invention includes a plurality of magnetic sensors according to any one of the above, and each magnetoresistive effect is set so that sensitivity axes of a pair of magnetoresistive effect elements are orthogonal to each other. An element is arranged. For example, the magnetic sensor module of the present invention is a geomagnetic sensor.

  According to the magnetic sensor of the present invention, the disturbance magnetic field from the direction orthogonal to the sensitivity axis can be easily drawn into the inside of the soft magnetic body from both end portions, and the magnetic shield effect can be effectively improved.

  1A and 1B are diagrams showing a part of a magnetoresistive element, in particular, a magnetoresistive effect element according to this embodiment (FIG. 1A is a partial plan view, and FIG. 1B is a height direction along the line A-A in FIG. FIG. 2 is an enlarged plan view of a part of the magnetic sensor in the present embodiment, particularly the magnetoresistive effect element part, and is drawn into the soft magnetic body of the present embodiment. FIG. 3 is a partial enlarged plan view of the magnetoresistive effect element portion of the magnetic sensor in the comparative example, and FIG. 3 shows the disturbance magnetic field from the orthogonal direction drawn into the soft magnetic body of the comparative example. FIG. 4 is a partially enlarged plan view showing the shape of the side end portion of the preferred soft magnetic body of the present embodiment, and FIG. 5 is a partially enlarged plan view showing the shape of the side end portion of the soft magnetic body in another embodiment. FIG. 6 and FIG. 6 show magnetic sensors in other embodiments. In particular, FIG. 7 is a plan view showing a portion of the magnetoresistive effect element, FIG. 7 is a partially enlarged cross-sectional view taken along the line BB shown in FIG. FIG. 9 is a diagram for explaining the relationship between the fixed magnetization direction of the fixed magnetic layer and the magnetization direction of the free magnetic layer that constitute the magnetoresistive effect element (element part), and the electric resistance value, and FIG. 9 shows the magnetoresistive effect element. FIG. 10 is a circuit configuration diagram of the magnetic sensor according to the present embodiment, and FIG. 11 is the same position as FIG. 7. FIG. 12 is a partial enlarged cross-sectional view showing a cross-section and a shape different from that in FIG. 7, FIG. 12 is a partial enlarged plan view showing a part of a preferred magnetoresistive effect element, particularly an element part, and FIG. It is a perspective view of a sensor module.

Hereinafter, the Y direction is referred to as a sensitivity axis direction, and the X direction orthogonal to the Y direction is referred to as an orthogonal direction.
The magnetic sensor module using the magnetic sensor 1 provided with the magnetoresistive effect element in the present embodiment is used as a geomagnetic sensor mounted on a portable device such as a cellular phone.

  As shown in FIG. 10, the geomagnetic sensor 1 includes a sensor unit 6 in which magnetoresistive effect elements 2 and 3 and fixed resistance elements 4 and 5 are bridge-connected, an input terminal 7 electrically connected to the sensor unit 6, The integrated circuit (IC) 11 includes a ground terminal 8, a differential amplifier 9, an external output terminal 10, and the like.

  As shown in FIGS. 1A and 1B, the magnetoresistive effect elements 2 and 3 are a plurality of elements that are elongated in the orthogonal direction (X direction) in which the element length L1 is formed longer than the element width W1. The parts 12 are arranged in parallel in the sensitivity axis direction (Y direction) at a predetermined interval, and the end parts of the element parts 12 are electrically connected by the connection electrode part 13 to form a meander shape. An electrode portion 15 connected to the input terminal 7, the ground terminal 8, and the output extraction portion 14 (see FIG. 10) is connected to one of the element portions 12 at both ends formed in a meander shape. The connection electrode part 13 and the electrode part 15 are nonmagnetic conductive materials, such as Al, Ta, Au. The connection electrode portion 13 and the electrode portion 15 are formed by sputtering or plating.

  Each element part 12 which comprises the magnetoresistive effect elements 2 and 3 is comprised by the same laminated structure shown in FIG. FIG. 9 shows a cut surface cut in the film thickness direction from the direction parallel to the element width W1.

  The element unit 12 is formed by stacking, for example, an antiferromagnetic layer 33, a pinned magnetic layer 34, a nonmagnetic layer 35, and a free magnetic layer 36 in this order from below, and the surface of the free magnetic layer 36 is covered with a protective layer 37. It has been broken. The element part 12 is formed by sputtering, for example.

The antiferromagnetic layer 33 is made of an antiferromagnetic material such as an Ir—Mn alloy (iridium-manganese alloy). The pinned magnetic layer 34 is formed of a soft magnetic material such as a Co—Fe alloy (cobalt-iron alloy). The nonmagnetic layer 35 is made of Cu (copper) or the like. The free magnetic layer 36 is made of a soft magnetic material such as a Ni—Fe alloy (nickel-iron alloy). The protective layer 37 is made of Ta (tantalum) or the like. In the above configuration, the nonmagnetic layer 35 is a giant magnetoresistive effect element (GMR element) formed of a nonmagnetic conductive material such as Cu, but a tunnel type magnetoresistive effect element formed of an insulating material such as Al ₂ O _3. (TMR element) may be used. Further, the stacked configuration of the element unit 12 illustrated in FIG. 9 is an example, and another stacked configuration may be used. For example, the free magnetic layer 36, the nonmagnetic layer 35, the pinned magnetic layer 34, the antiferromagnetic layer 33, and the protective layer 37 may be stacked in this order from the bottom.

  In the element unit 12, the magnetization direction of the pinned magnetic layer 34 is fixed by antiferromagnetic coupling between the antiferromagnetic layer 33 and the pinned magnetic layer 34. As shown in FIGS. 1 and 9, the pinned magnetization direction (P direction) of the pinned magnetic layer 34 faces the sensitivity axis direction (Y direction).

On the other hand, the magnetization direction (F direction) of the free magnetic layer 36 varies depending on the external magnetic field.
As shown in FIG. 8, when the external magnetic field Y1 acts from the same direction as the fixed magnetization direction (P direction) of the fixed magnetic layer 34 and the magnetization direction (F direction) of the free magnetic layer 36 faces the external magnetic field Y1 direction, The fixed magnetization direction (P direction) of the fixed magnetic layer 34 and the magnetization direction (F direction) of the free magnetic layer 36 approach parallel to each other, and the electric resistance value decreases.

  On the other hand, as shown in FIG. 8, the external magnetic field Y2 acts from the direction opposite to the fixed magnetization direction (P direction) of the fixed magnetic layer 34, and the magnetization direction (F direction) of the free magnetic layer 36 faces the external magnetic field Y2. Then, the fixed magnetization direction (P direction) of the fixed magnetic layer 34 and the magnetization direction (F direction) of the free magnetic layer 36 approach antiparallel, and the electrical resistance value increases.

  In addition, the element part 12 which comprises the magnetoresistive effect elements 2 and 3 may be an anisotropic magnetoresistive effect element (AMR element). However, the resistance change rate (MR ratio) with respect to the external magnetic field can be increased and the linearity of the resistance change rate (MR ratio) can be obtained when the element portion 12 constituting the magnetoresistive effect elements 2 and 3 is GMR or TMR. It is possible to detect the external magnetic field with high accuracy.

As shown in FIG. 1B, the element unit 12 is formed on the substrate 16. The element portion 12 is covered with an insulating layer 17 such as Al ₂ O ₃ or SiO ₂ . The space between the element portions 12 is also filled with the insulating layer 17. The insulating layer 17 is formed by sputtering, for example.

  As shown in FIG. 1B, the upper surface of the insulating layer 17 is formed on a flat surface by using, for example, a CMP technique. However, the upper surface of the insulating layer 17 may be formed as an uneven surface following the step between the element portion 12 and the substrate 16.

  As shown in FIGS. 1 (a) and 1 (b), a soft magnetic body 18 is provided between the element portions 12 constituting the magnetoresistive effect elements 2 and 3 and outside the element portion 12 located on the outermost side. Yes. The soft magnetic body 18 is formed into a thin film by, for example, sputtering or plating. The soft magnetic body 18 is made of NiFe, CoFe, CoFeSiB, CoZrNb, or the like. In FIGS. 1A and 1B, the width dimension W2 of the soft magnetic body 18 is larger than the element width W1 of the element portion 12, but it is not particularly limited.

  Further, the length L2 of the soft magnetic body 18 is longer than the element length L1 of the element portion 12, and as shown in FIG. 1A, the soft magnetic body 18 is in the orthogonal direction (X direction) of the element portion 12. An extending portion 18a extending in the orthogonal direction (X direction) is provided from both sides.

  As shown in FIG. 1B, the soft magnetic body 18 is formed on the insulating layer 17 between the element portions 12. Although not shown, the soft magnetic bodies 18 and between the soft magnetic bodies 18 are covered with an insulating protective layer.

  The magnetic sensor 1 shown in FIG. 1 is for detecting geomagnetism from a direction parallel to the sensitivity axis direction (Y direction). The element section 12 and the soft magnetic body 18 are arranged in a non-contact manner so that the soft magnetic body 18, the element section 12, and the soft magnetic body 18 are arranged in this order in the sensitivity axis direction.

  The fixed magnetization direction (P direction) of the fixed magnetic layer 34 is directed to the Y direction in the figure, which is the sensitivity axis direction.

  The element width W1 of the element portion 12 constituting the magnetoresistive effect elements 2 and 3 is preferably in the range of 2 to 6 μm in order to use shape anisotropy when used as a geomagnetic sensor (see FIG. 1 (b)). Moreover, it is suitable for the element length L1 of the element part 12 to be in the range of 60-100 micrometers (refer Fig.1 (a)). The film thickness T1 of the element portion 12 is preferably in the range of 200 to 300 mm (see FIG. 1B). In this embodiment, the width W2 of the soft magnetic body 18 is preferably in the range of 1 to 6 μm when used as a geomagnetic sensor (see FIG. 1B). The length L2 of the soft magnetic body 18 is preferably in the range of 80 to 200 μm (see FIG. 1A). The film thickness T2 of the soft magnetic body 18 is preferably in the range of 0.2 to 1 μm (see FIG. 1B). The aspect ratio (element length L1 / element width W1) of the element portion 12 is preferably 10 or more when used as a geomagnetic sensor. The aspect ratio (length dimension L2 / width dimension W2) of the soft magnetic material 18 is preferably equal to or greater than the aspect ratio of the element portion 12. Further, the length T8 of the extending portion 18a of the soft magnetic body 18 is preferably 20 μm or more (see FIG. 1A).

  Further, the interval (distance in the Y direction) T3 between the soft magnetic bodies 18 is preferably 2 to 8 μm in the width dimension W2 or more of the soft magnetic bodies (see FIG. 1B). The distance T4 in the Y direction between the element portion 12 and the soft magnetic body 18 located adjacent to the element portion 12 is preferably 0 to 3 μm (see FIG. 1B). The distance T5 in the height direction (Z direction) between the soft magnetic body 18 and the element portion 12 is preferably 0.1 to 1 μm (see FIG. 1B).

  In the present embodiment, soft magnetic bodies 18 that are not in contact with the element portion 12 are provided on both sides of the element portion 12 in the sensitivity axis direction (Y direction). The soft magnetic body 18 has an elongated shape in the orthogonal direction (X direction), like the element portion 12.

In the embodiment of FIG. 1, the soft magnetic body 18 is provided above the element portion 12.
As described above, the soft magnetic body 18 is formed with the extending portions 18a extending on both sides in the orthogonal direction (X direction) with respect to the element portion 12, as shown in FIGS. 1 (a), 2 and 4. Furthermore, the (maximum) width dimension W3 of each side end 18b of each extension 18a is formed larger than the width dimension W2 of the soft magnetic body 18 excluding the side end 18b.

  As shown in FIG. 1A, FIG. 2, and FIG. 4, the side end 18b is formed with tapered surfaces 18c and 18c in which the width of the side end 18b gradually increases in the direction away from the element portion 12. The width transition region 18d thus formed and the constant width region 18e formed by maintaining the maximum width (= W3) of the width transition region outside the orthogonal direction (X direction) of the width transition region 18d.

  As shown in FIG. 2, when a disturbance magnetic field is applied from the orthogonal direction (X direction), the disturbance magnetic field is easily drawn into the soft magnetic body 18 from the side end portion 18 b formed wide (to the soft magnetic body 18). The amount of magnetic flux of the disturbance magnetic field absorbed can be increased), and therefore the disturbance magnetic field from the orthogonal direction (X direction) acting on the element unit 12 can be effectively reduced, so that the magnetic shield effect is effectively improved. be able to.

  FIG. 3 is a comparative example. The soft magnetic body 18 of the comparative example is not formed with the wide side end portion 18b as in this embodiment, and the soft magnetic body 18 is formed with a constant width dimension W2. In the comparative example shown in FIG. 3, the amount of magnetic flux of the disturbance magnetic field absorbed by the soft magnetic body 18 is smaller than that of the present embodiment, and the disturbance magnetic field from the orthogonal direction (X direction) acting on the element unit 12 is implemented. It cannot be reduced as effectively as the form. Therefore, the configuration of the soft magnetic body 18 of the comparative example is inferior to the magnetic shield effect as compared with the present embodiment.

  As shown in FIG. 2, the side end 18b has a sensitivity such that the outer surface 18f in the sensitivity axis direction (Y direction) of the constant width region 18e of the side end 18b faces the element unit 12 in the orthogonal direction (X direction). It is preferable that it is formed so as to protrude in the axial direction (Y direction). An interval T9 (see FIG. 1B and FIG. 2) in the sensitivity axis direction (Y direction) between the element parts 12 is formed to be narrow, and the sensitivity axis direction (Y direction) between the soft magnetic body 18 and the element part 12 is formed. Although the width W2 of the soft magnetic body 18 formed on the side of the element portion 12 is reduced by forming the gap T4, the side end portion 18b is made as wide as possible. The magnetic shield effect can be improved.

  In the present embodiment, as shown in FIG. 4, the side end portion 18b is provided with a width transition region 18d formed by a tapered surface 18c. Thus, for example, not the tapered surface 18c but the sensitivity axis direction (Y The magnetic shield effect can be improved more effectively than in the case where the magnetic shield effect is formed with a vertical surface facing (direction).

  That is, when formed on the vertical plane, the disturbance magnetic field from the orthogonal direction (X direction) absorbed from the side end 18b is likely to leak out from the vertical plane portion. On the other hand, when formed with the tapered surface 18c as in the present embodiment, the disturbance magnetic field from the orthogonal direction (X direction) absorbed from the side end portion 18b follows the inclination of the tapered surface 18c and the width dimension is formed with W2. It is easy to focus toward the inside of the thin soft magnetic body 18, and the disturbance magnetic field is difficult to leak to the outside. Therefore, the magnetic shield effect can be more effectively improved by providing the width transition region 18d as in the present embodiment. The shape of the width transition region 18d is such that the angle θ formed by the extension line of the extending portion 18a and the tapered surface 18c is within a range of 20 to 70 degrees (see FIG. 4), and extends from the end portion of the element portion 12. The distance L5 to the connection point between the protruding portion 18a and the tapered surface 18c is three times or more of the element width W1, and the distance from the end of the element portion 12 to the distance L6 from the connection point between the tapered surface 18c and the outer surface 18f is It is preferably 5 times or more the element width W1 (see FIG. 2).

  In the present embodiment, as shown in FIG. 4, the maximum width (= W3) of the width transition region 18d is set outside the width transition region 18d in the orthogonal direction (X direction) at the side end portion 18b of the soft magnetic body 18. A constant-width region 18e formed to be maintained is provided, whereby a disturbance magnetic field from the orthogonal direction (X direction) absorbed from one side end portion 18b is released to the outside from the other side end portion 18b. The disturbance magnetic field can be prevented from being diffused and released to the outside.

  In addition, it is preferable that the connection point between the extending portion 18a and the tapered surface 18c and the connection point between the tapered surface 18c and the outer surface 18f are formed in an R shape instead of a square shape. Thereby, the leakage of the magnetic flux by the pattern angle of an outline part changing rapidly can be suppressed.

  The side end portion 18b in FIG. 5 is an embodiment of the present embodiment, but the side end portion 18b in FIG. 5 is formed only in the width transition region 18d, and the constant width region 18e shown in FIG. 4 is not formed. In the case of such a configuration, the disturbance magnetic field from the orthogonal direction (X direction) emitted from the side end 18b to the outside through the inside of the soft magnetic body 18 is easily diffused as shown in FIG.

  At this time, in particular, as shown in FIG. 1A, when the magnetoresistive effect elements 2 and 3 are arranged in parallel in the orthogonal direction (X direction), the magnetoresistive effect element 2 side is connected to the other magnetoresistive effect side. Since the disturbance magnetic field diffused toward the effect element 3 acts as a vector in the form of a quadrature component + sensitivity axis component, the magnetic shield effect is improved as compared with the case where the soft magnetic body 18 of the embodiment of FIG. 4 is used. Decreases and makes noise easier to ride. Therefore, in order to suppress the diffusion of the magnetic field, as shown in FIG. 4, it is preferable to provide the constant width region 18e formed with a constant width because the magnetic shield effect can be improved more effectively.

  By forming the side end portion 18b of the soft magnetic body 18 as shown in FIG. 4, when forming the magnetic sensor shown in FIG. 10, at least the magnetoresistive elements 2 and 3 are required in the sensor. Thus, even if a plurality of magnetoresistive elements 2 and 3 are arranged in the direction perpendicular to the sensitivity axis, the influence of the soft magnetic material of each magnetoresistive element on other magnetoresistive elements can be reduced. The degree of freedom of arrangement can be improved, which is preferable.

  Further, the same effect can be obtained not only when the magnetoresistive effect elements 2 and 3 as shown in FIG.

  The length dimension T11 in the orthogonal direction (X direction) of the constant width region 18e is preferably in the range of 20 to 80% when T11 / (T10 + T11) × 100 (%) (see FIG. 2). Further, the interval T12 in the sensitivity axis direction (Y direction) between the constant width regions 18e and 18e is preferably in the range of 1 to the element width W1 (see FIG. 2).

  In the embodiment shown in FIG. 1, the soft magnetic body 18 is formed above the element portion 12, but is not limited thereto. That is, the soft magnetic body 18 may be formed below the element portion 12 or may be formed beside it.

  As shown in FIG. 1A, soft magnetic bodies 25 indicated by dotted lines may be further provided on both sides of the soft magnetic body 18 provided on both sides in the sensitivity axis direction. Thereby, the magnetic shielding effect can be further enhanced. Note that this embodiment can also be applied to the soft magnetic body 25. That is, both the side end portions 25 b and 25 b in the orthogonal direction (X direction) of the soft magnetic body 25 are formed wide like the side end portions 18 b and 18 b of the soft magnetic body 18. In FIG. 1A, the soft magnetic body 25 is shown only on the magnetoresistive effect element 3 side, but the soft magnetic body 25 is preferably provided on both the magnetoresistive effect elements 2 and 3. .

  In another embodiment shown in FIG. 6, the magnetoresistive effect elements 2 and 3 are configured to include an element portion 12, an intermediate permanent magnet layer 21, and an outer permanent magnet layer 23. The intermediate permanent magnet layer 21 and the outer permanent magnet layer 23 are made of CoPt, CoPtCr, or the like, for example, formed by sputtering.

  As shown in FIG. 6, a plurality of element parts 12 are arranged side by side in the orthogonal direction (X direction) with an interval in the orthogonal direction (X direction), and the intermediate permanent part is within the interval between the element parts 12. A magnet layer 21 is interposed. Thereby, the element coupling body 22 extending in a band shape in the orthogonal direction (X direction) in which the element portions 12 are coupled via the intermediate permanent magnet layer 21 is configured. A plurality of element coupling bodies 22 are arranged in parallel at intervals in the sensitivity axis direction (Y direction), and an outer permanent magnet layer 23 is formed at the end of each element coupling body 22.

  As shown in FIG. 6, the outer permanent magnet layers 23 provided on both sides in the orthogonal direction (X direction) of the element coupling body 22 are connected by an electrode layer 19 formed of a good conductor such as Al, Au, or Cu. Has been. The electrode layer 19 is formed in a straight line shape (band shape) in the sensitivity axis direction (Y direction).

The magnetoresistive effect elements 2 and 3 can be formed in a meander shape with the configuration shown in FIG.
As shown in FIG. 6, the region between the element coupling bodies 22 and the outside of the element coupling bodies 22 located on both sides of the sensitivity axis direction (Y direction) of the element coupling bodies 22 are orthogonal to the element coupling bodies 22, respectively. A soft magnetic body 18 extending in the direction (X direction) is disposed. As shown in FIG. 6, the electrode layer 19 is located below the soft magnetic body 18.

  Further, as shown in FIG. 7, it is preferable that a low resistance layer 20 having a resistance value smaller than that of the intermediate permanent magnet layer 21 is formed on the intermediate permanent magnet layer 21 in an overlapping manner. The low resistance layer 20 is preferably formed of a nonmagnetic conductive material such as Au, Al, or Cu. The low resistance layer 20 is formed on the intermediate permanent magnet layer 21 by sputtering or plating. In order to increase the element resistance, a plurality of element portions 12 are connected to form a meander shape. However, since the resistance of the intermediate permanent magnet layer 21 is a parasitic resistance that does not contribute to a change in magnetoresistance, the intermediate permanent magnet layer 21 has an intermediate permanent shape as in this embodiment. By forming the low resistance layer 20 so as to overlap the magnet layer 21, the parasitic resistance can be reduced. The outer permanent magnet layer 23 also has a parasitic resistance. However, since the electrode layer 19 is overlaid on the outer permanent magnet layer 23 as shown in FIG. 6, the parasitic resistance can be effectively reduced.

  In the embodiment shown in FIG. 6, similarly to the embodiment shown in FIG. 1A, the magnetic shield effect can be effectively improved by forming the both side end portions 18b of the soft magnetic body 18 wide.

  In FIG. 6, the electrode portion 19 intersects the soft magnetic body 18, but an insulating layer is formed between the electrode portion 19 and the soft magnetic body 18. Alternatively, the electrode part 19 may bypass the outside of the soft magnetic body 18 without intersecting. The electrode layer 19 may be formed on either the lower part or the upper part of the soft magnetic body 18 as long as it is electrically insulated from the soft magnetic body 18.

  In FIG. 7, the element portion 12 is completely removed and the intermediate permanent magnet layer 21 and the low resistance layer 20 are formed. However, as shown in FIG. 11, the protective layer 37 and the free magnetic layer 36 are completely removed. By connecting with the intermediate permanent magnet layer 21 via the nonmagnetic layer 35, the parasitic resistance component is reduced by changing from the contact at the end face to the surface contact, and the fixed magnetic layer 34 is cut by cutting the fixed magnetic layer 34. By eliminating the magnetic domain disturbance, the magnetization direction of the pinned magnetic layer becomes uniform, so that a change in magnetoresistance due to a difference in magnetization angle with the free magnetic layer can be effectively generated. Further, in the configuration in which the intermediate permanent magnet layer 21 is provided between the element portions 12 by dividing the pinned magnetic layer 34 and the antiferromagnetic layer 33, the electrical contact between the intermediate permanent magnet layer 21 and the element portion 12 is on the side surface of each portion. The contact resistance, which is one of the parasitic resistances, is likely to increase because of contact, but the parasitic resistance can be reduced by making the electrical contact between the intermediate permanent magnet layer 21 and the element portion 12 planar as shown in FIG. Is preferable.

  As shown in FIG. 12, when the aspect ratio (element length L3 / element width W1) of the element part 12 sandwiched between the permanent magnet layers 21 is increased, the bias magnetic field from the permanent magnet layer 21 is changed to the element part. 12 is not properly supplied. For this reason, hysteresis tends to occur in the resistance change region when the magnetic field is applied from the direction orthogonal to the sensitivity axis direction (X direction) and the magnetic field strength is gradually increased. Therefore, the resistance change area with respect to the magnetic field (disturbance magnetic field) from the orthogonal direction is widened, so that the disturbance magnetic field resistance is easily lowered. Also, hysteresis is likely to occur even with a sensitive magnetic field, and the magnetic field response to the sensitive magnetic field is reduced. Therefore, it is preferable that the aspect ratio of the element unit 12 is small in order to appropriately supply a bias magnetic field to the entire element unit 12. Specifically, the aspect ratio of the element portion 12 is preferably 3 or less, and more preferably less than 1. As a result, the thickness of the permanent magnetic layer for appropriately supplying a bias magnetic field to the element portion 12 can also be reduced.

  The magnetic sensor 1 in this embodiment is used as a geomagnetic sensor (magnetic sensor module) shown in FIG. 13, for example. In each of the X-axis magnetic field detection unit 50, the Y-axis magnetic field detection unit 51, and the Z-axis magnetic field detection unit 52, a sensor unit of a bridge circuit shown in FIG. 10 is provided. In the X-axis magnetic field detection unit 50, the fixed magnetization direction (P direction) of the fixed magnetic layer 34 of the element unit 12 of the magnetoresistive effect elements 2 and 3 faces the X direction that is the sensitivity axis, and the Y-axis magnetic field detection unit In 51, the fixed magnetization direction (P direction) of the pinned magnetic layer 34 of the element portion 12 of the magnetoresistive effect elements 2 and 3 faces the Y direction which is the sensitivity axis, and in the Z-axis magnetic field detector 52, the magnetoresistive effect The pinned magnetization direction (P direction) of the pinned magnetic layer 34 of the element portion 12 of the elements 2 and 3 faces the Z direction that is the sensitivity axis.

  The X-axis magnetic field detection unit 50, the Y-axis magnetic field detection unit 51, the Z-axis magnetic field detection unit 52, and the integrated circuit (ASIC) 54 are all provided on the base 53. The formation surfaces of the magnetoresistive elements 2 and 3 of the X-axis magnetic field detector 50 and the Y-axis magnetic field detector 51 are both XY planes. Is formed on the X-Z plane, and the formation surface of the magnetoresistive effect elements 2 and 3 of the Z-axis magnetic field detection unit 52 is the magnetoresistive effect element 2 of the X-axis magnetic field detection unit 50 and the Y-axis magnetic field detection unit 51. , 3 are orthogonal to the formation surface.

  In the present embodiment, there is a magnetic shielding effect with respect to a direction orthogonal to the sensitivity axis direction, and appropriate sensitivity is provided with respect to the sensitivity axis direction. Therefore, even if two or more detection units among the X-axis magnetic field detection unit 50, the Y-axis magnetic field detection unit 51, and the Z-axis magnetic field detection unit 52 are provided on the base 53, each detection unit is orthogonal to the sensitivity axis direction. The magnetic field from the direction can be properly magnetically shielded, and the geomagnetism from the direction of the sensitivity axis of each detector can be detected appropriately.

  In addition to the configuration of FIG. 13, a module in which the geomagnetic sensor and the acceleration sensor shown in FIG. 13 are combined may be used.

(Example)
The magnetoresistive effect element 2 shown in FIG. 1 was formed. The element width W1 of the element portion 12 is 3 μm (see FIG. 1B), the width dimension W2 of the soft magnetic body 18 is 4 μm (see FIG. 1B), and the length dimension of the extending portion 18a of the soft magnetic body 18 is. T8 is 30 μm (see FIG. 1A), the length dimension T10 in the orthogonal direction (X direction) of the width transition region 18d is 5 μm (see FIG. 2), and the length in the orthogonal direction (X direction) of the constant width region 18e. The dimension T11 is 5 μm (see FIG. 2), the distance T12 in the sensitivity axis direction (Y direction) between the constant width regions 18e and 18e is 3 μm (see FIG. 2), and the sensitivity axis direction between the soft magnetic bodies 18 (Y direction). The interval T3 was set to 7 μm.

  In the experiment, the resistance change rate (MR ratio) of the magnetoresistive effect elements 2 and 3 was examined in a state where a magnetic field within a range of ± 5 Oe was applied in the direction orthogonal to the sensitivity axis direction (X direction). The experimental results are shown in FIG.

  As shown in FIG. 14, it was found that there was almost no magnetic sensitivity (−0.006% / Oe) with respect to the magnetic field in the orthogonal direction.

  Next, the resistance of the magnetoresistive effect elements 2 and 3 in the state where a magnetic field within a range of ± 5 Oe is applied in the sensitivity axis direction while applying a magnetic field of 0 Oe, +5 Oe, or −5 Oe in the orthogonal direction (X direction). The rate of change (MR ratio) was examined. The experimental results are shown in FIG.

  As shown in FIG. 15, the behavior of the resistance change rate (MR ratio) with respect to the external magnetic field is almost the same, and it has been found that the external magnetic field acting from the orthogonal direction (X direction) is appropriately shielded. . From the experimental results shown in FIG. 15, the SN ratio in the example was 8.5 dB.

(Comparative example)
The width transition region 18d and the constant width region 18e formed in the soft magnetic body 18 of the above embodiment were not formed, and a soft magnetic body having a constant width (see FIG. 3) was obtained. The length of the extended portion 18a with respect to the element portion of the soft magnetic material was set to 30 μm as in the example. All other dimensions were the same as in the examples.

  In the experiment, the resistance change rate (MR ratio) of the magnetoresistive effect elements 2 and 3 was examined in a state where a magnetic field within a range of ± 5 Oe was applied in the direction orthogonal to the sensitivity axis direction (X direction). The experimental results are shown in FIG.

  As shown in FIG. 16, it was found that the magnetic sensitivity (−0.037% / Oe) with respect to the magnetic field in the orthogonal direction was higher than that in the example (FIG. 14).

  Next, the resistance of the magnetoresistive effect elements 2 and 3 in the state where a magnetic field within a range of ± 5 Oe is applied in the sensitivity axis direction while applying a magnetic field of 0 Oe, +5 Oe, or −5 Oe in the orthogonal direction (X direction) The rate of change (MR ratio) was examined. The experimental results are shown in FIG.

  As shown in FIG. 17, the behavior of the resistance change rate (MR ratio) with respect to the external magnetic field does not match as in the embodiment (FIG. 15), and the behavior is not uniform, thereby acting from the orthogonal direction (X direction). It was found that the external magnetic field to be shielded was not properly shielded. From the experimental results shown in FIG. 17, the SN ratio in the comparative example was 2.7 dB.

The figure which shows the part of the magnetoresistive effect element especially of the magnetic sensor in this embodiment ((a) is a partial top view, (b) is a height direction (Z direction shown in the figure) along the AA line of (a). Partially enlarged cross-sectional view as seen from the direction of the arrow An enlarged plan view of a part of the magnetoresistive effect element of the magnetic sensor in the present embodiment, and an image diagram of a disturbance magnetic field from an orthogonal direction drawn into the soft magnetic body of the present embodiment, A partially enlarged plan view of a portion of the magnetoresistive effect element of the magnetic sensor in the comparative example, and an image diagram of the disturbance magnetic field from the orthogonal direction drawn into the soft magnetic body of the comparative example, The partial enlarged plan view which shows the shape of the side edge part of the preferable soft-magnetic body of this embodiment, The partially expanded plan view which shows the shape of the side edge part of the soft-magnetic body in another embodiment, The top view which shows the part of the magnetoresistive effect element especially of the magnetic sensor in other embodiment, The partial expanded sectional view which cut | disconnected in the height direction (Z direction shown in figure) along the BB line shown in FIG. 6, and was seen from the arrow direction, The figure for demonstrating the relationship between the fixed magnetization direction of the fixed magnetic layer which comprises a magnetoresistive effect element (element part), the magnetization direction of a free magnetic layer, and an electrical resistance value, A partial cross-sectional view showing a cut surface when the element part constituting the magnetoresistive effect element (element part) is cut from the film thickness direction; The circuit configuration diagram of the magnetic sensor of the present embodiment, 7 shows a cross-section at the same position as FIG. 7, and is a partially enlarged cross-sectional view of a shape different from FIG. A partially enlarged plan view showing a part of the element part in the form of a preferable magnetoresistive element, The perspective view of the geomagnetic sensor (magnetic sensor module) in this embodiment, Using the magnetoresistive effect element of the embodiment having the soft magnetic material shown in FIGS. 1, 2, and 4, the resistance change rate of the magnetoresistive effect element in a state where a magnetic field within a range of ± 5 Oe is applied in the orthogonal direction. A graph showing measurement results of (MR ratio), Using the magnetoresistive effect element of the example, the magnetoresistance was applied to each of the states in which a magnetic field within a range of ± 5 Oe was applied in the sensitivity axis direction while applying a magnetic field of 0 Oe, +5 Oe, or −5 Oe in the orthogonal direction (X direction). A graph showing a measurement result of a resistance change rate (MR ratio) of the effect element; Using the magnetoresistive effect element of the comparative example provided with the soft magnetic material shown in FIG. 3, the resistance change rate (MR ratio) of the magnetoresistive effect element is measured in a state where a magnetic field within a range of ± 5 Oe is applied in the orthogonal direction. A graph showing the results, Using the magnetoresistive effect element of the comparative example and applying a magnetic field in the range of ± 5 Oe in the sensitivity axis direction while applying a magnetic field of 0 Oe, +5 Oe, or −5 Oe in the orthogonal direction (X direction), the magnetoresistance A graph showing a measurement result of a resistance change rate (MR ratio) of the effect element;

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetic sensor 2, 3 Magnetoresistance effect element 4, 5 Fixed resistance element 6 Bridge circuit 7 Input terminal 8 Ground terminal 9 Differential amplifier 10 External output terminal 11 Integrated circuit 12 Element part 13 Connection electrode part 14 Output extraction part 15 Electrode part 16 Substrate 17 Insulating layer 18 Soft magnetic material 18a Extension portion 18b Side end 18c Tapered surface 18d Width transition region 18e Constant width region 19 Electrode 20 Low resistance layer 21 Intermediate permanent magnet layer 22 Element coupling body 23 Outer permanent magnet layer 33 Anti Ferromagnetic layer 34 Fixed magnetic layer 36 Free magnetic layer 50 X-axis magnetic field detector 51 Y-axis magnetic field detector 52 Z-axis magnetic field detector

Claims (6)

A magnetic sensor including a magnetoresistive element having a predetermined sensitivity axis,
The magnetoresistive effect element includes an element portion that exhibits a magnetoresistive effect, and a soft magnetic material,
The element part and the soft magnetic body are arranged in a non-contact manner in the order of the soft magnetic body, the element part, and the soft magnetic body in the direction of the sensitivity axis,
Both end portions of the soft magnetic body are at positions extending in the orthogonal direction from the element portion, and the width dimension of the both end portions is larger than the width dimension of the soft magnetic body excluding the both end portions. Magnetic sensor characterized by.   2. The magnetic sensor according to claim 1, wherein taper surfaces having the width dimension gradually increased toward the direction away from the element portion are formed at both end portions of the soft magnetic body.   The both end portions of the soft magnetic material are a width transition region formed by the tapered surface, and a constant width region formed by maintaining the maximum width of the width transition region outside the width transition region in the orthogonal direction. The magnetic sensor of Claim 2 comprised by these. A plurality of the element portions are arranged at intervals in the sensitivity axis direction, and the end portions of each element portion are electrically connected and formed in a meander shape,
4. The magnetic sensor according to claim 1, wherein the soft magnetic body is disposed on both sides of each element portion in the sensitivity axis direction by providing the soft magnetic body between the element portions. 5.   5. The magnetism according to claim 4, wherein a plurality of element portions and soft magnetic bodies formed in the meander shape are arranged in a direction orthogonal to the sensitivity axis, and the plurality of element portions constitute a part of a bridge circuit. Sensor.   6. A plurality of magnetic sensors according to claim 1, wherein each magnetoresistive element is arranged so that sensitivity axes of at least one set of the magnetoresistive elements are orthogonal to each other. A magnetic sensor module.

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