JP2016188774A - Magnetic field detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic field detection device with which a magnetic field induced in Z direction by a magnetic field inductive layer is detected by a magnetic detection element having a sensitivity axis in X direction orthogonal to the induction direction and which has a structure that makes it possible to reduce influences due to a disturbance magnetic field in other than the Z direction.SOLUTION: A magnetic field component in Z direction is induced by a magnetic field inductive layer 30 and given to a magnetic detection element 20 in X direction that is the same as the direction of its sensitivity axis, whereby a detection output is obtained. A bridge circuit is composed of a plurality of magnetic detection elements 20 and is configured so that no outputs are produced for a magnetic field component in the X direction. However, when the magnetic field component in the X direction acts upon the magnetic detection elements 20, a bias occurs in the resistance change of the magnetic detection elements 20 and the linearity of magnetic field detection operation in the Z direction declines. Thus, a guard layer 40 is formed, which makes it possible to reduce influences exerted by a disturbance magnetic field on the magnetic detection elements 20.SELECTED DRAWING: Figure 1A

Description

  The present invention relates to a magnetic field detection apparatus capable of detecting a magnetic field component in a direction orthogonal to the sensitivity axis of a GMR element using a magnetic detection element such as a GMR element arranged along an XY plane.

  In the magnetic field detection device described in Patent Document 1, a bridge circuit is configured by a magnetoresistive effect element having a sensitivity axis directed in the horizontal direction (X direction). The magnetoresistive effect element includes a vertical direction (Z direction). And a magnetic body formed of a soft magnetic material extending in the opposite direction. The magnetic field component in the vertical direction is induced by the magnetic material, and the horizontal component (X direction) of the leakage magnetic flux from the lower end of the magnetic material is detected by the magnetoresistive element. Thereby, it is possible to detect the intensity of the magnetic field in the vertical direction.

  In this magnetic field detection device, it is necessary that the detection output based on the horizontal direction component (X direction component) of the disturbance magnetic field is not superimposed on the original detection output. Therefore, even when the resistance value of each magnetoresistive effect element changes due to a magnetic field component in the horizontal direction (X direction), the bridge circuit is configured so that the change can be canceled out.

WO 2011/068146 A1

  7 and 8 are explanatory diagrams for explaining the problem of the conventional magnetic field detection device as described in Patent Document 1. FIG. FIG. 7A shows the magnetic body 101 and the magnetoresistive effect element 102 opposed thereto in a plan view, and FIG. 7B shows an end face of FIG. 7A viewed from the direction of arrow B. FIG. The direction of the sensitivity axis of the magnetoresistive effect element 102 is the X direction.

  As shown in FIG. 7B, the vertical magnetic field Hz to be measured is induced in the Z direction by the magnetic body 101, and the leakage magnetic field Hz 1 from the lower end of the magnetic body 101 is given to the magnetoresistive effect element 102. It is done. Since the resistance value of the magnetoresistive effect element 102 changes according to the strength of the X direction component of the leakage magnetic field Hz1, the strength of the magnetic field component Hz can be detected by obtaining the detection output of the bridge circuit.

  When a magnetic field Hx in the X direction in the same direction as the sensitivity axis that is a disturbance magnetic field acts on the magnetic field detection device, the resistance value of each magnetoresistive element changes. Similarly, in the case of the magnetic field Hy in the Y direction, which is a disturbance magnetic field, it seems that the direction of the magnetic field is orthogonal to the sensitivity axis of the magnetoresistive effect element, so that it does not affect the sensitivity. As shown in A), the magnetic field Hy1 entering the magnetic body 101 and the magnetic field Hy2 exiting the magnetic body 101 out of the magnetic field Hy in the Y direction include a magnetic field component in the X direction. The resistance value of each magnetoresistive element changes.

  As described above, when the magnetic field Hx in the X direction or the magnetic field Hy in the Y direction acts uniformly on the magnetoresistive effect element, the bridge circuit is configured so as to cancel the change in the resistance value of the magnetoresistive effect element. . However, when the magnetic field Hx in the X direction or the magnetic field Hy in the Y direction is increased, as shown in FIG. 8, there is a new problem that the balance of sensitivity of the individual magnetoresistive elements is lowered.

  In FIG. 8, the horizontal axis indicates the strength H of the magnetic field in the X direction acting on the magnetoresistive effect element, and the vertical axis indicates the resistance change ΔR of each magnetoresistive effect element. As a characteristic of the magnetoresistive effect element, the linearity of the resistance change ΔR can be secured with respect to the change of the magnetic field strength H near the origin (O) of the magnetic field H, but the magnetic field strength is X direction more than the origin (O). When shifting to the (+) side or the (−) side of this, the linearity is lowered. When a magnetic field Hx or Hy that is a disturbance magnetic field acts and a bias magnetic field H01 acts on the magnetoresistive effect element in the X direction that is the sensitivity axis direction, the resistance change ΔR of the magnetoresistive effect element at that time already becomes the bias value ΔR01. ing. When the vertical magnetic field Hz to be measured is applied in that state, the linearity of the resistance change ΔR cannot be ensured with respect to the intensity change of the magnetic field Hz. As a result, the sensitivity of the detection output obtained from the bridge circuit is different between the (+) side and the (−) side of the external magnetic field, and the balance of sensitivity cannot be ensured.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide a magnetic field detection device having a structure capable of compensating for a reduction in sensitivity balance due to a disturbance magnetic field.

The present invention relates to a magnetic sensing element arranged along an XY plane of an XYZ coordinate in which three axes are orthogonal to each other, and a magnetic field component in the Z direction having a height in the Z direction in the X direction. In the magnetic field detection device having a magnetic field induction layer applied to the magnetic detection element,
The magnetic sensing element having a sensitivity axis in the X direction forms a resistance change portion, and a plurality of the resistance change portions are connected to form a bridge circuit, and the magnetic field induction layer is opposed to each resistance change portion. And
A guard layer made of a magnetic material is provided, and the guard layer passes through the interval between the plurality of resistance change portions arranged at intervals in the X direction and extends in the Y direction; and It has a pair of horizontal guard part extended in the X direction continuously with the both ends of the Y direction of the said vertical guard part, It is characterized by the above-mentioned.

In the magnetic field detection device of the present invention, the first resistance change portion and the third resistance change portion showing resistance changes opposite to the external magnetic field in the same direction are arranged on one side in the X direction, A second resistance change section and a fourth resistance change section showing resistance changes opposite to the external magnetic field are arranged on the other side in the X direction;
The vertical guard portion is disposed within the space between the first resistance change portion and the third resistance change portion and the second resistance change portion and the fourth resistance change portion, and is spaced in the Y direction. A first resistance change portion and a third resistance change portion, and a second resistance change portion and a fourth resistance change portion are respectively disposed between the pair of lateral guard portions formed in this manner. Can be configured as

  In the magnetic field detection apparatus of the present invention, it is preferable that the guard layer is formed of the same magnetic material as the magnetic field induction layer.

  The height dimension of the guard layer in the Z direction is preferably equal to or lower than the height dimension of the magnetic field induction layer.

  In the magnetic field detection device of the present invention, it is preferable that the resistance change portion is disposed symmetrically on both sides in the X direction with respect to the vertical guard portion.

  Furthermore, in the magnetic field detection device of the present invention, an other-direction magnetic field detection device that detects a magnetic field component in the X direction or the Y direction may be disposed in a region aligned with the resistance change unit in the X direction.

  In this case, it is preferable that a guard portion extending in the Y direction does not exist in an adjacent portion between the resistance change portion and the other-direction magnetic field detection device.

  Moreover, it is preferable that the X-side end portion of the lateral guard portion facing the other-direction magnetic field detection device does not protrude in a direction closer to the other-direction magnetic field detection device than the magnetic field induction layer.

  Furthermore, it is preferable that the resistance change unit and the other resistance change unit provided in the other-direction magnetic field detection device are provided in the same chip.

  The magnetic field detection device of the present invention can induce a disturbance magnetic field in the Y direction by the vertical guard portion of the guard layer formed of a magnetic material, and can induce a disturbance magnetic field in the X direction and the Y direction by the pair of lateral guard portions. It is possible to prevent a disturbance magnetic field other than the magnetic field in the Z direction to be measured from acting on the magnetic sensing element, and to reduce the decrease in sensitivity balance shown in FIG.

  The guard layer is composed of a vertical guard portion and a horizontal guard portion, and there are no guard portions extending in the Y direction on both the left and right sides of the resistance change portion in the X direction. Or, when adopting a structure in which another resistance change part that detects the magnetic field component in the Y direction is used, the disturbance magnetic field drawn into the guard part or the disturbance magnetic field coming out of the guard part is sensitive to other resistance change parts. Application of an axial bias magnetic field can be suppressed.

The top view which shows the whole structure of the magnetic field detection apparatus of embodiment of this invention, The top view which shows the state which removed the magnetic induction layer and the guard layer in the magnetic detection apparatus shown to FIG. 1A, 1 is an equivalent circuit diagram of the magnetic field detection device shown in FIG. An enlarged sectional view of a magnetic sensing element provided in the magnetic field sensing device, (A) is explanatory drawing which shows the operation | movement by which the magnetic field component induced | guided | derived by the magnetic field induction layer is detected by the 1st resistance change part and the 2nd resistance change part, (B) was induced | guided | derived by the magnetic field induction layer Explanatory drawing which shows the operation | movement by which a magnetic field component is detected by the 3rd resistance change part and the 4th resistance change part, (A) is explanatory drawing which shows the state in which the external magnetic field of the X direction was applied to the 1st resistance change part and the 2nd resistance change part, (B) is the 3rd resistance change part and 4th resistance. Explanatory drawing which shows the state in which the external magnetic field of the X direction was applied to the change part, Explanatory drawing explaining the magnetic field induction effect by the guard layer, (A) is a top view which shows the schematic structure of arrangement | positioning of the magnetic body and magnetoresistive effect element for demonstrating the conventional subject, (B) is an end elevation view of the arrow B of (A), For explaining the conventional problem, a diagram showing the sensitivity characteristics of the magnetoresistive effect element,

  A magnetic field detection device Sz shown in FIG. 1A detects a component in the Z direction of an external magnetic field. The magnetic field detection device Sz can detect an external magnetic field in three orthogonal directions in combination with a magnetic field detection device Sx that detects a component in the X direction of an external magnetic field and a magnetic field detection device Sy that detects a component in the Y direction. It becomes. This magnetic field detection device is used as a geomagnetic sensor.

  In FIG. 1A, a magnetic field detection device Sy that detects a magnetic field in the Y direction is arranged side by side at a position adjacent to the X1 direction of the magnetic field detection device Sz of the embodiment of the present invention that detects a magnetic field in the Z direction.

  FIG. 1B shows a state in which the magnetic field induction layer 30 and the guard layer 40 located above the magnetic field detection device Sz are removed. As shown in this figure, the magnetic field detection device Sz includes a first resistance change unit 1 and a second resistance change unit 2 as well as a third resistance change unit 3 and a fourth resistance change unit 4 on a substrate 11. , Along the XY plane. Each of the resistance change portions 1, 2, 3, 4 is formed to extend long in the Y direction.

  As shown in the equivalent circuit diagram of FIG. 2, the first resistance change unit 1 and the third resistance change unit 3 are connected in series, and the second resistance change unit 2 and the fourth resistance change are connected. The unit 4 is connected in series. The third resistance change unit 3 and the second resistance change unit 2 are connected to the terminal 5 through the wiring unit 5a, and the power supply voltage Vcc is applied to the terminal 5. A connection portion between the first resistance change unit 1 and the fourth resistance change unit 4 is connected to a terminal 6 through a wiring portion 6a, and the terminal 6 is grounded. A connection intermediate portion between the first resistance change unit 1 and the third resistance change unit 3 is connected to the first detection terminal 7 via the wiring unit 7a, and the second resistance change unit 2 and the fourth resistance are connected. An intermediate point of connection with the changing unit 4 is connected to the second detection terminal 8 via the wiring unit 8a.

  A differential output between the output of the first detection terminal 7 and the output of the second detection terminal 8 of the full bridge circuit becomes the detection output of the magnetic field detection device Sz.

  As shown in FIG. 1B, in the first resistance change section 1, two magnetic detection elements 20 elongated in series in the Y direction are arranged in two rows. In each row, two magnetic sensing elements 20 arranged in the Y direction are connected in series by an intermediate electrode portion 20a. In the first resistance change unit 1, the end portions on the Y1 side of each column of the magnetic detection elements 20 arranged in two rows are connected by the conductive coupling layer 9 a, and the first resistance change unit 1 Twenty columns are connected in a so-called meander pattern. The fourth resistance change unit 4 has the same structure as that of the first resistance change unit 1 and is configured to have the same planar pattern. In the fourth resistance change unit 4, end portions on the Y1 side of the magnetic detection elements 20 arranged in two rows are connected by a conductive coupling layer 9 b.

  The second resistance change unit 2 includes magnetic detection elements 20 elongated in the Y direction in two rows. In each row, two magnetic detection elements 20 arranged in the Y direction are connected in series by the intermediate electrode portion 20a. Yes. The end portions on the Y1 side of the two rows of magnetic sensing elements 20 are connected to each other by the conductive coupling layer 9c. The third resistance change unit 3 has the same structure and the same pattern as the second resistance change unit 2, and the Y1 side of each column of the magnetic sensing elements 20 provided in two columns is a conductive coupling layer 9 d. Are connected to each other.

  The wiring portions 5a, 6a, 7a, 8a, the terminals 5, 6, 7, 8 and the conductive connection layers 9a, 9b, 9c, 9d are formed of a low resistance material such as copper or silver.

  FIG. 3 shows a cross-sectional view of the magnetic sensing element 20 provided in each of the resistance change portions 1, 2, 3, and 4, taken along a cutting plane parallel to the YZ plane.

  An insulating underlayer 12 is formed on the surface of the substrate 11, and a magnetic sensing element 20 in which metals are laminated in multiple layers is formed thereon. The metal layer constituting the magnetic sensing element 20 is formed by a sputtering process or a CVD process.

  The magnetic sensing element 20 is a magnetoresistive effect element layer (GMR layer) that exhibits a giant magnetoresistive effect, and a fixed magnetic layer 22, a nonmagnetic layer 23, and a free magnetic layer 24 are sequentially stacked on the seed layer 21. The free magnetic layer 24 is covered with a protective layer 25.

  The pinned magnetic layer 22 has a laminated ferrimagnetic structure having a first pinned layer 22a and a second pinned layer 22b, and a nonmagnetic intermediate layer 22c located between the first pinned layer 22a and the second pinned layer 22b. It is. The first fixed layer 22a and the second fixed layer 22b are formed of a soft magnetic material such as a CoFe alloy (cobalt-iron alloy). The nonmagnetic intermediate layer 22c is made of Ru (ruthenium) or the like.

  The pinned magnetic layer 22 having a laminated ferrimagnetic structure has a so-called self-pinned structure in which the magnetizations of the first pinned layer 22a and the second pinned layer 22b are pinned antiparallel. The self-pinned structure does not use an antiferromagnetic layer to pin the magnetization of the pinned magnetic layer 22. In the pinned magnetic layer 22 having the laminated ferrimagnetic structure, the magnetization direction is fixed by antiferromagnetic coupling between the first pinned layer 22a and the second pinned layer 22b. The magnetization direction of the pinned magnetic layer 22 is the magnetization direction of the second pinned layer 22b. In all the magnetic sensing elements 20 provided in all the resistance change portions 1, 2, 3, and 4, the pinned magnetic layer 22 is fixed. The direction of the fixed magnetization P is directed in the X2 direction. Therefore, the direction of the sensitivity axis of the magnetic detection element 20 is the X direction.

  The nonmagnetic layer 23 shown in FIG. 3 is formed of a nonmagnetic material such as Cu (copper). The free magnetic layer 24 is formed of a soft magnetic material such as a NiFe alloy (nickel-iron alloy). The free magnetic layer 24 has a length dimension in the longitudinal direction (Y direction) that is sufficiently larger than a width dimension in the lateral direction (X direction), and the magnetization is aligned in the X2 direction due to its shape anisotropy. . Therefore, there is no longitudinal biasing structure for aligning the magnetization of the free magnetic layer 24 in the longitudinal direction. The protective layer 25 covering the free magnetic layer 24 is formed of Ta (tantalum) or the like.

  As shown in FIG. 1A, a magnetic field induction layer 30 facing each magnetic sensing element 20 from the Z direction is provided in all of the resistance change portions 1, 2, 3, and 4. The magnetic field induction layer 30 allows each magnetic sensing element 20 to detect an external magnetic field in the Z direction.

  As shown in FIG. 1A, the magnetic field induction layer 30 is formed by being divided into four locations. Each magnetic field guiding layer 30 has four guiding portions 30a and one shielding portion 30d extending in the Y direction. Both end portions in the Y direction of each guide portion 30a and shielding portion 30d are connected by a connecting portion 30b. As shown in FIG. 3, in the magnetic sensing element 20, the free magnetic layer 24 is covered with a protective layer 25, but an insulating layer (not shown) is formed on the protective layer 25, and the upper surface of the insulating layer is a flat surface. The magnetic field induction layer 30 is formed thereon by a plating process or the like. The magnetic field induction layer 30 is made of a soft magnetic material such as a Ni—Fe alloy.

  As shown in FIGS. 4A and 4B, the guiding portion 30a of the magnetic field guiding layer 30 is formed in a wall shape so as to rise in the Z direction. As shown in FIG. 4A, in the first resistance change unit 1 and the second resistance change unit 2, the magnetic sensing element 20 is disposed below the lower end surface 30c of each induction unit 30a. The magnetic sensing element 20 is formed in a plane parallel to the XY plane, and the center of the magnetic sensing element 20 is arranged so as to be displaced in the X1 direction with respect to the width center in the X direction of the lower end surface 30c. . As shown in FIG. 4B, in the third resistance change unit 3 and the fourth resistance change unit 4, the magnetic sensing element 20 is disposed below the lower end surface 30c of the induction unit 30a. The magnetic detection element 20 is formed in a plane parallel to the XY plane, and the center of the magnetic detection element 20 is arranged so as to be displaced in the X2 direction with respect to the width center in the X direction of the lower end surface 30c. Yes.

  In FIGS. 4A and 4B, the lower end surface 30c of the guiding portion 30a and a part of the magnetic sensing element 20 overlap in the Z direction, but the first resistance changing portion 1 and the second resistance changing portion. 2, the magnetic sensing element 20 may be arranged so that the magnetic sensing element 20 does not overlap with the lower end surface 30c of the guiding portion 30a in the Z direction. The same applies to the third resistance change unit 3 and the fourth resistance change unit 4.

  In the first resistance change unit 1 and the second resistance change unit 2, the misalignment distance in which the magnetic sensing element 20 is displaced in the X1 direction from the center of the lower end surface 30c, the third resistance change unit 3 and the second resistance change unit 2 In the resistance change section 4, the absolute value is set to be equal to the positional displacement distance at which the magnetic sensing element 20 is displaced in the X2 direction from the center of the lower end surface 30 c.

  As shown in FIG. 1, in each magnetic field induction layer 30, the shielding portion 30d is formed at an end portion on the X1 side or an end portion on the X2 side. The shielding part 30d is formed at a position farther to the X2 side than the first resistance change part 1 and a position farther to the X1 side than the fourth resistance change part 4. Each shielding portion 30 d is formed to extend in the Y direction and does not face the magnetic sensing element 20. The shielding part 30d has a wall shape like the guiding part 30a, and is formed to rise in the Z direction.

  FIG. 4 shows a state in which the magnetic field detection device Sz detects a magnetic field component Hv in the Z1 direction. The magnetic field component Hv in the Z1 direction is induced by the guiding portion 30a of the magnetic field guiding layer 30, but the magnetic field emitted from the lower end surface 30c of the guiding portion 30a is planarly dispersed. As shown in FIG. 4A, in the first resistance change unit 1 and the second resistance change unit 2, the magnetic detection element 20 detects a magnetic field component Hh1 in the X1 direction. As shown in FIG. 4B, in the third resistance change unit 3 and the fourth resistance change unit 4, the magnetic detection element 20 detects the magnetic field component Hh <b> 2 directed in the X2 direction.

  In the resistance change portions 1, 2, 3, and 4, in all the magnetic sensing elements 20, the direction of the fixed magnetization P of the fixed magnetic layer 22 is the X2 direction. In the first resistance change unit 1 and the second resistance change unit 2 shown in FIG. 4A, the electric resistance value of the magnetic sensing element 20 increases as the strength of the magnetic field component Hv in the Z1 direction increases. In the third resistance change unit 3 and the fourth resistance change unit 4 shown in FIG. 4B, the electric resistance value of the magnetic sensing element 20 decreases as the strength of the magnetic field component Hv in the Z1 direction increases. Become.

  As a result, as shown in the equivalent circuit diagram of FIG. 2, the voltage of the detection terminal 7 located in the middle between the first resistance change unit 1 and the third resistance change unit 3 connected in series fluctuates, and the series The voltage of the detection terminal 8 located in the middle of the second resistance change unit 2 and the fourth resistance change unit 4 connected to the fluctuates. Since the voltage change between the detection terminal 7 and the detection terminal 8 is opposite in polarity, the intensity of the magnetic field component Hv in the Z1 direction can be detected by taking the voltage difference between the detection terminal 7 and the detection terminal 8. it can.

  Further, the magnetic field component directed in the Z2 direction is also guided to the magnetic field induction layer 30, and at this time, the magnetic field component in the X direction is detected by each magnetic sensing element 20. Therefore, it is possible to detect the magnetic field intensity in the Z2 direction.

  On the other hand, the magnetic field detection device Sz is designed to have basically no sensitivity with respect to the magnetic field component in the X direction by configuring the full bridge circuit shown in FIG.

  The first resistance change unit 1 and the second resistance change unit 2 shown in FIG. 5A and the third resistance change unit 3 and the fourth resistance change unit 4 shown in FIG. The direction of the fixed magnetization P of the fixed magnetic layer 22 of the sensing element 10 is the same. Therefore, as shown in FIG. 5, when the magnetic field component Hvx in the X2 direction is given as the disturbance magnetic field to the magnetic field detection device Sz, the resistance value decreases in all the resistance change units 1, 2, 3, and 4. Therefore, the potentials of the first detection terminal 7 and the second detection terminal 8 do not change. Therefore, the detection output of the magnetic field detection device Sz does not change. This is the same when a magnetic field component in the X1 direction acts.

  Further, as shown in FIG. 7A, when a magnetic field in the Y1 direction or the Y2 direction acts on the magnetic field detection device Sz as a disturbance magnetic field, the magnetic field component attracted from the side to the guiding portion 30a of the magnetic field guiding layer 30. There is a magnetic field component Hy2 that escapes laterally from Hy1 and the guiding portion 30a, and the resistance value of each magnetic sensing element 20 varies depending on the X-direction component of the magnetic field components Hy1 and Hy2. However, also with respect to this magnetic field, if the magnetic field in the Y1 direction or the Y2 direction is uniform, the resistance values of the magnetic sensing elements 20 provided in the resistance change units 1, 2, 3, and 4 change with the same polarity. The detection output of the magnetic field detection device Sz does not change.

  However, as shown in FIG. 8, when the disturbance magnetic field in the X1 direction and the X2 direction or the Y1 direction and the Y2 direction acts on the magnetic sensing element 20 which is a GMR element with a strong intensity, the magnetic field becomes a bias magnetic field H01 in the X direction. The resistance change ΔR becomes the bias value ΔR1. If a magnetic field component Hv in the Z direction that should be measured appears when the disturbance magnetic field is acting, the strength of the magnetic field acting on the external magnetic sensing element 20 changes with the value added to the bias magnetic field H01. At this time, the linearity of the resistance change of the magnetic sensing element 20 cannot be secured, and the differential output of the outputs detected by the respective magnetic sensing elements 20 in the bridge circuit composed of the resistance change portions 1, 2, 3, 4 When the magnetic field Hz changes in the Z1 direction, the sensitivity differs depending on whether the magnetic field Hz changes in the Z2 direction.

  In order to solve this problem, a guard layer 40 is provided in the magnetic field detection device Sz as shown in FIG. 1A.

  The guard layer 40 is formed by a plating process using the same soft magnetic material as the magnetic field induction layer 30. The guard layer 40 and the magnetic field induction layer 30 are formed separately without being connected to each other. The guard layer 40 absorbs a disturbance magnetic field in the X direction and the Y direction, but needs to absorb as little as possible the measurement magnetic field in the Z direction. Therefore, the height dimension of the guard layer 40 in the Z direction is the same as that of the magnetic field induction layer 30, but is preferably lower than that.

  In the guard layer 40, a vertical guard portion 41 and a pair of horizontal guard portions 42, 42 are integrally formed. The vertical guard part 41 is located in the middle of the first resistance change part and the third resistance change part 3 on the X2 side and the second resistance change part and the fourth resistance change part 4 on the X1 side, It is formed so as to extend linearly in the Y direction.

  The lateral guard portions 42, 42 extend linearly in the X direction continuously to the Y1 side end portion and the Y2 side end portion of the vertical guard portion 41. The first resistance change unit 1 and the third resistance change unit 3 are located on the X2 side with respect to the vertical guard unit 41, and are positioned between the Y1 side horizontal guard unit 42 and the Y2 side horizontal guard unit 42. doing. The second resistance change unit 2 and the fourth resistance change unit 4 are located closer to the X1 side than the vertical guard unit 41, and are positioned between the Y1 side horizontal guard unit 42 and the Y2 side horizontal guard unit 42. doing.

  Both the Y1 side guard part 42 and the Y2 side guard part 42 protrude to the X2 side from the first resistance change part 1, and protrude from the fourth resistance change part 4 to the X1 side.

  The vertical guard part 41 and the horizontal guard parts 42 and 42 are formed to have a larger width dimension than both the guiding part 30a and the shielding part 30d of the magnetic field guiding layer 30. By making the width dimension of the guard layer 40 larger than that of the magnetic field induction layer 30, disturbance magnetic fields in the X direction and the Y direction can be easily absorbed by the guard layer 40.

  Further, the width dimension in the X direction of the vertical guard portion 41 is formed larger than the width dimension in the Y direction of the horizontal guard portions 42 and 42. As a result, the saturation magnetic flux density of the vertical guard unit 41 is higher than that of the horizontal guard units 42 and 42, and variations in sensitivity of the magnetic field detection device Sz can be reduced even when a large disturbance magnetic field acts. Further, by slightly lowering the saturation magnetic flux density of the lateral guard portions 42, 42, the lateral guard portions 42, 42 are prevented from excessively absorbing the magnetic field component in the Y direction that the adjacent magnetic field detection device Sy tries to detect. It is possible to reduce variations in sensitivity of the magnetic field detection device Sy.

  Further, as shown in FIG. 1A, the X1 side ends of the horizontal guard portions 42, 42 are at the same position as the X1 side edge of the magnetic field induction layer 30 positioned on the X1 side of the vertical guard portion 41, or Alternatively, it is preferably formed at a position closer to the vertical guard portion 41 than the side edge portion. Also with this configuration, it is possible to suppress the horizontal guard portions 42 and 42 from excessively absorbing the Y-direction magnetic field component that the adjacent magnetic field detection device Sy is to detect, and to reduce variations in sensitivity of the magnetic field detection device Sy. become.

  FIG. 6 shows a simulation result showing a distribution of magnetic flux density when a disturbance magnetic field in the Y1 direction acts on the magnetic field detection device Sz.

  In this simulation result, since the disturbance magnetic field in the Y1 direction is captured by the lateral guard portion 42 of the guard layer 40 and guided to the longitudinal guard portion 42, the disturbance acting on the respective resistance change portions 1, 2, 3, 4 The magnetic flux density of the magnetic field is low.

  Further, each magnetic field induction layer 30 is provided with a shielding part 30d, and this shielding part 30d is located on the X2 side away from the first resistance change part 1 and X1 more than the fourth resistance change part 4. Each is provided at a position off the side. Therefore, a part of the disturbance magnetic field is also absorbed by the shielding part 30d, and the magnetic flux density of the disturbance magnetic field acting on each resistance change part 1, 2, 3, 4 can be suppressed low.

  Therefore, the density of the magnetic flux component in the sensitivity axis direction (X direction) of the disturbance magnetic field in the Y direction acting on the magnetic sensing elements 20 of the resistance change portions 1, 2, 3, 4 can be reduced. As shown in FIG. 5, it becomes possible to prevent a large bias magnetic field H01 from acting on each magnetic sensing element 20. Therefore, when a magnetic field in the Z direction to be measured is applied, the magnetic field components Hh1 and Hh2 shown in FIG. 4 start from the vicinity of the origin (O) shown in FIG. 8 and maintain linearity. The detection operation can be performed with.

  The guard layer 40 includes a vertical guard layer 41 and horizontal guard portions 42 and 42, and no guard portion extending in the Y direction exists at the end portion on the X1 side and the end portion on the X2 side. That is, there is no guard portion extending in the Y direction along the line L shown in FIGS.

  Since the guard part attracts the external magnetic field and releases the attracted magnetic field, the magnetic flux is disturbed so as to be directed to the guard part in the vicinity of the guard part. In the example shown in FIG. 1, a magnetic field detection device Sy that detects a magnetic field component in the Y direction is provided at a position adjacent to the X1 direction of the magnetic field detection device Sz, and a resistance change unit for detecting the magnetic field in the Y direction is provided. It exists adjacent. If a guard layer is provided on the L line, a part of the magnetic field component in the Y direction is attracted to the guard layer and the direction of the magnetic flux is disturbed. Thus, the magnetic field component of the magnetic field detector Sy cannot be accurately detected, and the balance of the detection output is lost in the entire magnetic field detection device Sy.

  However, in the embodiment shown in FIG. 1, the guard layer 40 is composed of a vertical guard portion 41 located at the center and horizontal guard portions 42 and 42 located at the end portions on the Y1 side and the Y2 side. Is not provided with a guard layer. Therefore, the influence on the magnetic flux density is reduced in the vicinity of the L line, and the magnetic flux component in the Y1 direction is hardly disturbed on the X1 side from the boundary line BB shown in FIG. Therefore, as shown in FIG. 1, the resistance change part of the magnetic field detection device Sy for detecting the magnetic field in the Y direction is brought close to the magnetic field detection device Sz for detecting the magnetic field in the Z direction in the X1 direction. Can be arranged. Therefore, the magnetic field detection devices Sx, Sy, and Sz that detect magnetic field components in the three axial directions can be densely arranged in a small area.

  Next, when a disturbance magnetic field in the X direction acts on the magnetic field detection device Sz, the disturbance magnetic field is attracted and guided to the lateral guard portions 42 and 42 located on the Y1 side and the Y2 side, so that each resistance changing unit 1 , 2, 3 and 4, the magnetic flux density of the disturbance magnetic field in the X direction can be reduced.

  Further, the shielding portion 30d of the magnetic field induction layer 30 is present at a position further away from the first resistance change portion 1 toward the X2 side, and the magnetic field is also present at a location further away from the fourth resistance change portion 4 toward the X1 side. Since the shielding part 30d of the induction layer 30 exists, the disturbance magnetic field in the X direction also directly affects the magnetic sensing elements 20 of the resistance change parts 1, 2, 3, and 4 by this shielding part 30d. Can be suppressed.

  In the present invention, the magnetic field detection device arranged adjacent to the magnetic field detection device Sz may detect a magnetic field in the X direction. In this specification, the magnetic field detection device that detects a magnetic field in the X direction or the Y direction adjacent to the magnetic field detection device Sz is the other-direction magnetic field detection unit. It is preferable that the resistance change portions 1, 2, 3, and 4 constituting the magnetic field detection device Sz and the other resistance change portion constituting the other-direction magnetic field detection portion are formed on the same substrate 11. Are preferably formed in the same chip.

  In addition, the vertical guard part 41 and the horizontal guard parts 42 and 42 may be formed separately. In this case, the distance of the gap between the vertical guard part 41 and the horizontal guard parts 42 and 42 is set so that the disturbance magnetic field can be preferentially absorbed by the guard layer 40. It is preferable that the distance to the induction layer 30 is shorter.

  In the present invention, an intermediate guard portion extending in the X direction may be continuously extended from the vertical guard portion 41 in the middle between the Y1 direction and the Y2 direction of the guard layer 40 shown in FIG.

Sz Magnetic sensing element 1 1st resistance change part 2 2nd resistance change part 3 3rd resistance change part 4 4th resistance change part 11 Substrate 20 Magnetic sensing element 22 Fixed magnetic layer 23 Nonmagnetic layer 24 Free magnetic layer 30 Magnetic field induction layer 30a Guide part 30d Shielding part 40 Guard layer 41 Vertical guard part 42 Horizontal guard part

Claims (9)

A magnetic sensing element arranged along an XY plane of XYZ coordinates in which three axes are orthogonal to each other, and a magnetic field component having a height in the Z direction and guiding a magnetic field component in the Z direction in the X direction. In a magnetic field detection device having a magnetic field induction layer applied to a detection element,
The magnetic sensing element having a sensitivity axis in the X direction forms a resistance change portion, and a plurality of the resistance change portions are connected to form a bridge circuit, and the magnetic field induction layer is opposed to each resistance change portion. And
A guard layer made of a magnetic material is provided, and the guard layer passes through the interval between the plurality of resistance change portions arranged at intervals in the X direction and extends in the Y direction; and A magnetic field detection device comprising: a pair of horizontal guard portions extending in the X direction continuously with both ends of the vertical guard portion in the Y direction. A first resistance change portion and a third resistance change portion that exhibit resistance changes opposite to an external magnetic field in the same direction are arranged on one side in the X direction, and resistances that oppose an external magnetic field in the same direction. The second resistance change portion and the fourth resistance change portion showing the change are arranged on the other side in the X direction,
The vertical guard portion is disposed within the space between the first resistance change portion and the third resistance change portion and the second resistance change portion and the fourth resistance change portion, and is spaced in the Y direction. A first resistance change portion and a third resistance change portion, and a second resistance change portion and a fourth resistance change portion are respectively disposed between the pair of lateral guard portions formed in this manner. Item 1. A magnetic field detection apparatus according to Item 1.   The magnetic field detection device according to claim 1, wherein the guard layer is formed of the same magnetic material as the magnetic field induction layer.   4. The magnetic field detection device according to claim 1, wherein a height dimension of the guard layer in the Z direction is equal to or lower than a height dimension of the magnetic field induction layer. 5.   5. The magnetic field detection device according to claim 1, wherein the resistance change unit is arranged symmetrically on both sides in the X direction with respect to the vertical guard unit.   6. The magnetic field detection device according to claim 1, wherein an omnidirectional magnetic field detection device that detects a magnetic field component in the X direction or the Y direction is arranged in a region aligned with the resistance change unit in the X direction.   The magnetic field detection device according to claim 6, wherein a guard portion extending in the Y direction does not exist in an adjacent portion between the resistance change unit and the other-direction magnetic field detection device.   8. The magnetic field detection according to claim 6, wherein an end portion on the X side of the lateral guard portion facing the other-direction magnetic field detection device does not protrude in a direction closer to the other-direction magnetic field detection device than the magnetic field induction layer. apparatus.   The magnetic field detection device according to claim 6, wherein the resistance change unit and the other resistance change unit provided in the other-direction magnetic field detection device are provided in the same chip.