JP2014174061A - Magnetic sensor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic sensor device in which a magnetic field generated in a magnetic field coil can be efficiently applied to a magnetoresistance effect element.SOLUTION: In the magnetic sensor device, a magnetoresistance effect element, a pair of magnetic bodies which are arranged so that the magnetoresistance effect element is interposed between them, and a magnetic field coil which forms a magnetic field for the magnetoresistance effect element are formed on a substrate. The magnetic coil is configured to include conductor patterns arranged on a lower magnetic field coil layer and an upper magnetic field coil which are laminated with the magnetic bodies therebetween, and the upper magnetic field coil layer is close to a formation surface of the lower magnetic field coil layer, in an arrangement position of the magnetoresistance effect element.

Description

  The present invention relates to a magnetic sensor device that measures magnetic field strength.

  Giant magnetoresistive elements (GMR elements) have higher detection sensitivity in the vicinity of the zero magnetic field than Hall effect elements, and thus are often applied to magnetic balanced current sensors. However, when a GMR element is used, if the applied magnetic field is zero, the magnetization state of the free layer is not stable and the output becomes unstable. Therefore, a magnetic field having a known magnitude (bias magnetic field) is applied to the GMR element in a direction orthogonal to the direction of the magnetic field to be measured so as not to affect the measurement magnetic field (for example, patents). Reference 1). Further, in a magnetic balance type current sensor, it has been studied to provide a magnetoresistive effect element between yokes (Patent Document 2).

JP 2011-039021 A International Publication No. 2010/143666 Pamphlet

  As in Patent Document 2, it is considered that the magnetic field coil is configured so that a feedback current is passed through a thin-film magnetic field coil and the vicinity of the GMR element is set to a zero magnetic field. However, in order to keep the current consumed by the magnetic field coil low, it is desired to efficiently apply the magnetic field generated by the magnetic field coil to the GMR element. With the configurations of Patent Documents 1 and 2, it is not easy to further reduce the current consumption.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a magnetic sensor device capable of efficiently applying a magnetic field generated by a magnetic field coil to a magnetoresistive element.

  The present invention for solving the problems of the conventional example described above is a magnetic sensor device, comprising a magnetoresistive effect element, a pair of magnetic bodies arranged with the magnetoresistive effect element sandwiched therebetween, and the pair of magnetism A magnetic sensor device in which a magnetic field coil wound around a body and forming a magnetic field to the magnetoresistive effect element is formed on a substrate, wherein the magnetic field coil is disposed in a stacked manner with the magnetic material interposed therebetween A conductive pattern disposed on each of the magnetic field coil layer and the upper magnetic field coil layer, wherein the upper magnetic field coil layer is close to a formation surface of the lower magnetic field coil layer at a position where the magnetoresistive effect element is disposed; It is what.

  The magnetic sensor device according to one aspect of the present invention includes a first magnetoresistive element and a first magnetoresistive element arranged in a direction orthogonal to the magnetosensitive axis direction, the magnetosensitive axis directions being antiparallel to each other. The first pair of first layers disposed mainly on a layer different from the layer including the second magnetoresistive effect element and opposed to each other with a gap disposed at a position corresponding to the arrangement of the first magnetoresistive effect element. A magnetic material and a magnetic material layer including a pair of second magnetic materials arranged opposite to each other with a gap disposed at a position corresponding to the arrangement of the second magnetoresistive effect element, and a laminate sandwiching the magnetic material layer Magnetic field coil conductors that are arranged and wound around each of the pair of first magnetic bodies and each of the pair of second magnetic bodies in a direction that intersects the magnetosensitive axis direction of the magnetoresistive element. Each including a lower magnetic field coil layer and an upper magnetic field coil layer It said upper field coil layer is formed in proximity to the forming surface of the lower magnetic field coil layer within a predetermined range comprising said magnetoresistive element.

  Further, here, in a bias coil layer disposed via an insulating layer with respect to the upper magnetic field coil layer over a range overlapping the range where the first and second magnetic bodies are disposed, a spiral bias is provided. A coil may be arranged.

  According to the present invention, the magnetic field generated by the magnetic field coil can be efficiently applied to the magnetoresistive effect element.

It is a schematic diagram showing the example of composition of the magnetic sensor device concerning an embodiment of the invention. It is a schematic explanatory drawing showing the structural example of the magnetic sensor part which concerns on embodiment of this invention. It is a schematic circuit diagram of the circuit part in the magnetic sensor apparatus which concerns on embodiment of this invention. It is explanatory drawing showing the example of the conductor pattern of the magnetic field coil of the magnetic sensor apparatus which concerns on embodiment of this invention. It is explanatory drawing showing the example of another conductor pattern of the magnetic field coil of the magnetic sensor apparatus which concerns on embodiment of this invention. It is explanatory drawing showing the example of the manufacturing method of the magnetic sensor part which concerns on embodiment of this invention. It is a schematic diagram showing another structural example of the magnetic sensor apparatus which concerns on embodiment of this invention. It is explanatory drawing showing the effect of the magnetic sensor apparatus which concerns on embodiment of this invention. It is a schematic circuit diagram showing another example of the circuit part in the magnetic sensor apparatus which concerns on embodiment of this invention. It is a schematic circuit diagram showing another example of the circuit part in the magnetic sensor apparatus which concerns on embodiment of this invention. It is a schematic circuit diagram showing the further another example of the circuit part in the magnetic sensor apparatus which concerns on embodiment of this invention. It is a schematic circuit diagram showing another example of the circuit part in the magnetic sensor apparatus which concerns on embodiment of this invention.

  Embodiments of the present invention will be described with reference to the drawings. The magnetic sensor device 1 according to the embodiment of the present invention is arranged in the vicinity of a conductor through which a measured current I flows in the Y-axis direction, as illustrated in FIG. The magnetic sensor device 1 includes a magnetic sensor unit 10 and a circuit unit 15. The magnetic sensor unit 10 includes a magnetoresistive effect element 11, a pair of magnetic bodies 12 a and 12 b disposed opposite to each other with the magnetoresistive effect element 11 interposed therebetween, and a magnetic field coil 13 wound around each magnetic body 12. It is comprised including. Further, a bias coil 14 may be further laminated on the magnetic sensor unit 10 of the magnetic sensor device 1 illustrated in FIG. 1A (FIG. 1B). Furthermore, a circuit unit 15 is connected to the magnetic field coil 13 and the magnetoresistive effect element 11 in these.

  Here, the magnetoresistive effect element 11, the magnetic body 12, the magnetic field coil 13, and the bias coil 14 are formed in a thin film. Specifically, as illustrated in FIG. 2, the magnetic sensor unit 10 of the present embodiment includes a substrate 20, a lower magnetic field coil layer 21 including a part of a conductor pattern forming the magnetic field coil 13, a magnetic material layer 22, and The upper magnetic field coil layer 23 including another part of the conductor pattern forming the magnetic field coil 13 and the bias coil layer 24 provided with the bias coil are laminated in this order with the insulator layer 25 interposed therebetween. Here, the side closer to the substrate 20 is referred to as the lower side, and the side far from the substrate 20 is referred to as the upper side. However, in the actual use field, the upper magnetic field coil layer 23 side is not necessarily disposed vertically upward. It does not mean what should be done. FIG. 2 is a cross-sectional view of the magnetic sensor unit 10 according to the present embodiment when the surface parallel to the X-axis direction passing through the center of the magnetoresistive element 11 is broken.

The magnetoresistive effect element 11 is, for example, a GMR element. In the example of the present embodiment, the magnetoresistive effect element 11 is arranged in the plane of the lower magnetic field coil layer 21 and has a strip shape. The short direction of the GMR element is the magnetosensitive axis direction in this embodiment (the direction parallel to the magnetosensitive axis is the X-axis direction, and the right side of the drawing is the positive direction). Specifically, for the magnetosensitive axis direction, if a GMR element having a fixed layer is used as the magnetoresistive element 11, the direction parallel or antiparallel to the magnetization direction of the fixed layer is the magnetosensitive axis direction. When an artificial lattice type GMR element (so-called laminated GMR element) is used as the magnetoresistive effect element 11, the direction perpendicular to the direction of the bias applied to the laminated GMR element is the magnetosensitive axis direction.
The GMR element having the fixed layer may be a spin valve type giant magnetoresistive element (SVGMR element). Here, in the magnetoresistive effect element 11, the fixed layer is magnetized in the width direction (a direction perpendicular to the longitudinal direction), and exhibits a resistance value according to the strength of the magnetic field in the width direction. In an example of the present embodiment, the magnetoresistive effect element 11 is arranged so that its width direction is parallel to the Y axis. As the spin valve type giant magnetoresistive effect element, a method of fixing the magnetization direction of the fixed layer with a self pin may be adopted. As the self-pinned fixed layer, for example, a structure in which a ferromagnetic layer, a Ru layer, and a ferromagnetic layer are stacked and the ferromagnetic layers are antiferromagnetically coupled to each other through the Ru layer can be used. .

  The magnetic body 12 is arranged in the plane of the magnetic layer 22 and is an alloy of iron and nickel (permalloy). In an example of the present embodiment, the thickness is 1 μm, the saturation magnetic flux density Bs = 1.0T, Magnetic permeability μi = 2000. In the present embodiment, the magnetic body 12 basically has a rectangular shape having a longitudinal direction in the direction of the magnetic sensitive axis of the magnetoresistive effect element 11, and on the magnetoresistive effect element 11 side, it is short on the magnetoresistive effect element 11 side. A trapezoidal portion (S) having sides is formed.

  The magnetic field coil 13 includes a conductor pattern wound around the magnetic body 12. Specifically, the magnetic field coil 13 of the present embodiment electrically connects the conductor patterns respectively disposed on the lower magnetic field coil layer 21 and the upper magnetic field coil layer 23 that are stacked with the magnetic layer 22 interposed therebetween. Formed. A specific configuration example of the magnetic field coil 13 will be described later.

  The bias coil 14 is disposed in the plane of the bias coil layer 24. The bias coil 14 has a spiral shape and includes a plurality of conductor patterns parallel to the magnetosensitive axis direction at a position corresponding to the magnetoresistive element 11 and its vicinity. A specific example of the bias coil 14 will also be described later.

  In these lower magnetic field coil layer 21, magnetic material layer 22, upper magnetic field coil layer 23, and bias coil layer 24, the portions without the conductor, magnetoresistive effect element 11, magnetic material 12, etc. are filled with an insulator. Each layer is formed into a layered body having a predetermined thickness.

  As illustrated in FIG. 3A, the circuit unit 15 includes fixed resistance elements 31, 32, 33 and an amplifier 34. Here, the fixed resistance elements 31, 32, and 33 constitute a bridge circuit together with the magnetoresistive effect element 11. Specifically, one end of the magnetoresistive effect element 11 and one end side of the fixed resistance element 31 are connected and connected to a common terminal (GND). Further, the other end of the magnetoresistive effect element 11 and one end of the fixed resistance element 33 are connected, and the other end of the fixed resistance element 31 and one end of the fixed resistance element 32 are connected. The other end sides of the fixed resistance elements 32 and 33 are connected to each other and connected to the power supply terminal Vcc.

  The amplifier 34 supplies a voltage signal corresponding to the potential difference between the other end side of the magnetoresistive effect element 11 and the other end side of the fixed resistance element 31 to one end side of the magnetic field coil 13. The other end of the magnetic field coil 13 is connected to a common terminal (GND). The output of the amplifier 34 is supplied to the magnetic field coil 13. Specifically, the output of the amplifier 34 is connected to one end side (end portion on the negative side of the X axis) of the magnetic field coil 13 of the magnetic sensor unit 10. The other end side of the magnetic field coil 13 is connected to a common terminal (GND) via a resistor R and the like.

  According to this example, a voltage having a magnitude corresponding to the resistance change of the magnetoresistive effect element 11 (or a magnitude proportional to the resistance change if the resistance change is small) is applied to the magnetic field coil 13. Here, the resistance values of the fixed resistance elements 31, 32, and 33 are r1, r2, and r3, and the resistance value of the magnetoresistance effect element 11 when there is no magnetic field (external magnetic field) generated by the current I to be measured is r. R × r2 = r1 × r3. Then, when the resistance value of the magnetoresistive effect element 11 changes depending on the magnitude of the external magnetic field, a voltage corresponding to the change in the resistance value is applied to the magnetic field coil 13, and with respect to the magnetosensitive axis direction of the magnetoresistive effect element 11. A magnetic field (cancellation magnetic field) having a magnitude in proportion to the voltage is formed opposite to the external magnetic field. The external magnetic field generated by the current I to be measured is canceled by this canceling magnetic field. At this time, the amount of current i flowing through the magnetic field coil 13 is proportional to the current I to be measured. Therefore, the circuit unit 15 outputs a signal representing the current amount i as an output signal. Specifically, a resistor R is connected between the other end of the magnetic field coil 13 and the common terminal (GND), and the potential difference between both ends of the resistor R is output as a voltage signal representing the magnitude of the current amount i. What should I do?

  Next, a specific configuration example of the magnetic field coil 13 will be described. In the present embodiment, the conductor pattern forming a part of the magnetic field coil 13 disposed on the lower magnetic field coil layer 21 is as illustrated in FIG. That is, the lower magnetic field coil layer 21 has linear conductors L1, L2, ..., Li, ..., Ln parallel to the longitudinal direction of the magnetoresistive element 11 (direction relative to the magnetosensitive axis direction: Y-axis direction). However, a plurality of the magnetic bodies 12 are arranged side by side in the X-axis direction over the range where the magnetic bodies 12 are arranged. In FIG. 4, the range corresponding to the position where the magnetic body 12 is arranged is indicated by a broken line.

  A conductor pattern forming a part of the magnetic field coil 13 disposed on the upper magnetic field coil layer 23 of the magnetic field coil 13 is as illustrated in FIG. The upper magnetic field coil layer 23 is provided with an end conductor U1 disposed at a position in the X-axis direction corresponding to the conductor L1 of the lower magnetic field coil layer 21. The upper magnetic field coil layer 23 is a linear portion parallel to the longitudinal direction of the magnetoresistive effect element 11 (direction with respect to the magnetosensitive axis direction: Y-axis direction), and is the i-th ( n-1> i> 2) has a portion P overlapping the conductor Li, and is adjacent to this portion P via the bent portion Q in the X-axis direction (the (i-1) th in the lower magnetic field coil layer 21) The conductors U2, U3,... Uj including the end R overlapping the one end of the conductor Li-1 are arranged in parallel to each other in the X-axis direction. Here, “overlapping” means that they appear to overlap in plan view (when viewing the XY plane). In other words, “overlap with the conductor Li” means that the conductor Li is disposed at a position on the X axis corresponding to the position in the X axis direction where the conductor Li is disposed, and means that the conductor Li appears to overlap.

  Furthermore, one end side in the Y-axis direction overlaps with the upper magnetic field coil layer 23 on the other end side of the (i−1) -th conductor Li-1 adjacent to the one direction in the X-axis, The other end side in the Y-axis direction has a portion that overlaps with one end side of the (Li + 1) -th conductor Li + 1 (in the lower magnetic field coil layer 21) adjacent to the other direction in the X-axis. A central conductor Uc having a linear portion arranged in parallel to the longitudinal direction of the magnetoresistive effect element 11 (direction with respect to the magnetosensitive axis direction: Y-axis direction) is arranged. The linear portion of the central conductor Uc is disposed at a position overlapping the magnetoresistive effect element 11. That is, the central conductor Uc corresponds to a conductor that is superimposed on the magnetoresistive effect element and is orthogonal to the magnetosensitive axis direction in the present invention.

  Further, the upper magnetic field coil layer 23 has conductors Uj + 1, Uj + 1 having a shape obtained by rotating the conductors U1, U2,..., Uj by an angle π with the center C of the center conductor Uc (the center of gravity of the center conductor Uc) as the rotation center. ... Un (where n = 2j) is arranged. In addition, the overlapping ends of the conductor Ui and the conductors Li-1, Li, or Li + 1 are electrically connected via via conductors that penetrate the insulating layer 25 and the magnetic layer 22.

  Thereby, the conductor U1 arranged in the upper magnetic field coil layer 23 is electrically connected to the other end side of the conductor L1 arranged in the lower magnetic field coil layer 21 through the via conductor H1. The conductor L1 is electrically connected to the conductor U2 disposed on the upper magnetic field coil layer 23 via the via conductor H2 on one end side thereof. The other end of the conductor U2 is connected to the other end of the conductor L2 disposed in the lower magnetic field coil layer 21 via the via conductor H3. Hereinafter, the conductors are sequentially electrically connected so as to be wound around the magnetic body 22 such as the conductor U3, the conductor L3,..., Thereby forming the magnetic field coil 13 wound around the magnetic body 22.

  The bias coil 14 is a spiral coil in which conductive wires parallel to the X-axis direction and conductive wires parallel to the Y-axis direction are alternately connected. A predetermined bias current is supplied to the bias coil 14. The bias coil 14 is arranged so that a plurality of conductive wires parallel to the X-axis direction of the bias coil 14 are arranged along the longitudinal direction of the magnetoresistive effect element 11.

  Further, in the magnetic sensor unit 10 of the present embodiment, as illustrated in FIG. 2, the upper magnetic field coil layer 23 overlaps the predetermined range including the magnetoresistive effect element 11 in the magnetoresistive effect element 11. It is formed so as to be convex toward. That is, the center line in the thickness direction of the upper magnetic field coil layer 23 (Z-axis direction with the normal direction standing on the surface of the substrate 20 as the Z-axis) is located at a distance z23 from the surface of the substrate 20 outside the above range. Yes, the portion overlapping the magnetoresistive effect element 11 is located at a distance z23 ′ (z23 ′ <z23) from the surface of the substrate 20, and the distance between them is closer to the portion overlapping the magnetoresistive effect element 11. It is inclined (is a slope) in the XZ plane so as to approach the surface. This range is, for example, a width ξ from the center of the magnetoresistive effect element 11 (intersection when a diagonal line is drawn in the rectangle of the magnetoresistive effect element 11 forming a rectangle) to the X axis positive direction and the negative direction respectively. The part of / 2. When the length of the magnetoresistive element 11 in the short direction is w, ξ ≧ w, and in the Y-axis direction, this range is the positive direction of the Y-axis from the center of the magnetoresistive element 11, And a portion of length η / 2 in the negative direction. At this time, assuming that the length of the magnetoresistive element 11 in the longitudinal direction is l, η> l.

  Specifically, as the lower magnetic field coil layer 21 is closer to the magnetoresistive effect element 11 in the above-mentioned range, the thickness thereof is reduced, and a constant thickness is obtained at a portion overlapping the magnetoresistive effect element 11. This is realized by forming as described above. In this example, the magnetic layer 22 laminated on the lower magnetic field coil layer 21 also protrudes toward the magnetoresistive element 11 at a portion overlapping the above range, and the magnetic layer included in the magnetic layer 22 The body 12 is also bent and arranged in the XZ plane within the above range in parallel with the center line in the thickness direction of this layer.

  At this time, the bias coil layer 24 including the bias coil 14 may be formed so as to be parallel to the surface of the substrate 20. Further, the bias coil layer 24 including the bias coil 14 is also predetermined including the magnetoresistive effect element 11 in the same manner as the upper magnetic field coil layer 23 (so that any part is parallel to the magnetic field coil layer 23). It may be formed so as to protrude toward the magnetoresistive effect element 11 at a portion overlapping the range.

  Hereinafter, an example of the manufacturing method of the magnetic sensor unit 10 according to such an example will be described. As illustrated in FIG. 6, in this example, first, a conductor portion to be included in the lower magnetic field coil layer 21 of the magnetic field coil 13 is formed on the substrate 20 by sputtering. Further, the magnetoresistive effect element 11 is formed in a thin film at a predetermined position (S1). The magnetoresistive effect element 11 may be protected by an alumina protective film. Next, an insulator film is formed to a predetermined thickness near the conductor portion of the magnetic field coil 13 of the lower magnetic field coil layer 21 (S2). At this time, the insulator film is not formed on the magnetoresistive effect element 11.

  As a result, a concave portion (its end portion may be a slope) that is concave by a predetermined size in both directions of the X axis with the magnetoresistive element 11 as the center is obtained. Thus, the lower magnetic field coil layer 21 and the insulator layer are formed.

  Then, the magnetic body 12 is formed on the lower magnetic field coil layer 21 by a method such as sputtering (S3). The magnetic body 12 is formed so that the end on the magnetoresistive effect element 11 side is convex toward the magnetoresistive effect element 11 according to the shape of the insulator film. Further, an insulator film having a predetermined thickness is formed on the upper part (S4). When the magnetoresistive effect element 11 is protected with an alumina protective film, it is not necessary to form an insulating film immediately above the magnetoresistive effect element 11. Since this insulator film is also formed along the shape of the lower magnetic field coil layer 21, a recess is formed around the magnetoresistive effect element 11. Thus, the magnetic layer 22 is obtained.

  Here, in the insulator film of the magnetic layer 22, a hole is formed at a position corresponding to the via hole to form a via conductor connected to the conductor pattern included in the lower magnetic field coil layer 21. Then, a conductor portion of the magnetic field coil 13 to be included in the upper magnetic field coil layer 23 is formed on the insulator film laminated on the magnetic layer 22 by sputtering or the like (S5). At this time, the via conductor is electrically contacted at a position corresponding to the via hole of the conductor portion. The conducting wire of the magnetic field coil 13 in the upper magnetic field coil layer 23 thus formed is also arranged along the shape in the concave portion, and is formed in the direction toward the magnetoresistive effect element 11 in the XZ plane. Further, in the concave portion, the upper portion of the upper magnetic field coil layer 23 is a portion outside the concave portion of the magnetic body 12 disposed on the magnetic layer 22 (away from the lower magnetic field coil layer 21 in the Z-axis direction of the magnetic body 12). Is closer to the lower magnetic field coil layer 21 on which the magnetoresistive effect element 11 is arranged.

  Further, an insulator film having a predetermined thickness is formed on the upper magnetic field coil layer 23 (S6). The insulator film may be formed so that the thickness from the surface of the substrate 20 is substantially constant everywhere, but it may be uneven. Thereby, the upper magnetic field coil layer 23 and the insulator layer are obtained.

  Further, a conductive wire of the bias coil 14 having a spiral shape on the XY plane is arranged on the insulator layer by a method such as sputtering (S7). Further, an insulator film having a predetermined thickness is formed on the upper part (S8). The bias coil 14 is also formed in a direction toward the magnetoresistive effect element 11 in the XZ plane, with a conducting wire disposed along the shape in the concave portion.

  Further, in the present embodiment, the magnetic sensor unit 10 may be a pair instead of one. Specifically, in this example, as shown in FIG. 7, a pair of magnetic sensor units 10a and 10b are arranged side by side in a direction (Y-axis direction) orthogonal to the magnetosensitive axis direction. At this time, the magnetosensitive effect elements 11 included in each of the magnetic sensor units 10a and 10b are arranged such that the magnetosensitive axis directions are parallel to the X axis and antiparallel to each other. In the example of FIG. 7, the magnetosensitive axis direction of the magnetoresistive effect element 11 a of the magnetic sensor unit 10 a (hereinafter referred to as the first magnetoresistive effect element for distinction) is the negative X-axis direction, and the magnetoresistive resistance of the magnetic sensor unit 10 b The magnetosensitive axis direction of the effect element 11b (hereinafter referred to as a second magnetoresistive effect element for distinction) is assumed to be the positive direction of the X axis.

  At this time, the magnetic field coils 13a and 13b included in the magnetic sensor units 10a and 10b are connected in series. Specifically, the end portion on the positive side in the X-axis direction of the magnetic field coil 13a included in the magnetic sensor unit 10a (the side connected to the common terminal GND when the magnetic sensor unit 10 is single) is magnetic. The magnetic coil 13b included in the sensor unit 10b is connected to the end of the magnetic field coil 13b on the X axis negative direction side, and the end of the magnetic field coil 13b on the X axis positive direction side is connected through a resistor R or the like to a common terminal ( GND).

  In this example, each layer (lower magnetic field coil layer, magnetic layer, upper magnetic field coil layer) of the magnetic sensor units 10a and 10b is arranged on the same surface in the Z-axis direction. That is, in this example, a part of the conductor pattern of the magnetic field coils 13a, 13b and the first and second magnetoresistance effect elements 11a, 11b in both the magnetic sensor units 10a, 10b are arranged on one lower magnetic field coil layer, The magnetic bodies 12a, b of both the magnetic sensor units 10a, 10b are arranged on one magnetic layer, and so on, and the surfaces of the respective layers are configured to substantially coincide.

  Further, as illustrated in FIG. 7, the bias coil 14 is a spiral coil in which conductive wires parallel to the X-axis direction and conductive wires parallel to the Y-axis direction are alternately connected. In FIG. 7, the bias coil 14 is transmitted through and the outline of the outline is shown by a dotted line so that the situation in the lower part can be easily understood. It is arranged in a shape. A predetermined bias current is supplied to the bias coil 14. That is, the bias coil 14 has a first conductor group in which current flows to one side of the X axis and a second conductor group in which current flows to the other side of the X axis as conductors parallel to the X axis direction. The bias coil 14 is arranged so that the first conductor group of the bias coil 14 overlaps the first magnetoresistive element 11a and the second conductor group overlaps the second magnetoresistive element 11b. The bias coil 14 is formed over a range where the magnetic bodies 12a and 12b included in the magnetic sensor units 10a and 10b are arranged. That is, the width of the bias coil 14 in the X-axis direction is substantially greater than or equal to the length of the magnetic bodies 12a and 12b in the X-axis direction.

  The circuit unit 15 of the magnetic sensor 1 according to this example includes fixed resistance elements 32 and 33 and an amplifier 34 as illustrated in FIG. Here, the fixed resistance elements 32 and 33 constitute a bridge circuit together with the pair of magnetoresistance effect elements 11a and 11b. Specifically, one end of the first magnetoresistive effect element 11a and one end side of the second magnetoresistive effect element 11b are connected, and these one end sides are further connected to a common terminal (GND). Connected. Further, the other end of the first magnetoresistance effect element 11a is connected to one end of the fixed resistance element 33, and the other end of the second magnetoresistance effect element 11b is connected to one end of the fixed resistance element 32. . The other end sides of the fixed resistance elements 32 and 33 are connected to each other and connected to the power supply terminal Vcc. In consideration of the electrical resistance of the conductive wire itself, the circuit unit 15 may be configured by omitting the fixed resistance elements 32 and 33. Furthermore, instead of the fixed resistance elements 32 and 33, another pair of magnetoresistance effect elements 11c and 11d may be used. In this case, another magnetic sensor 1 illustrated in FIG. 7 is used, and the magnetoresistive effect elements 11c and 11d included in the other magnetic sensor 1 are connected in place of the fixed resistance elements 32 and 33 here.

  The amplifier 34 supplies a voltage signal corresponding to the potential difference between the other end side of the first magnetoresistive effect element 11 a and the other end side of the second magnetoresistive effect element 11 b to the one end side of the magnetic field coil 13. . The other end of the magnetic field coil 13 is connected to a common terminal (GND). The output of the amplifier 34 is supplied to the magnetic field coil 13. Specifically, the output of the amplifier 34 is connected to the end portion on the X-axis negative side of the magnetic field coil 13a of the magnetic sensor unit 10a. Further, the end (the other end side of the magnetic field coil) on the X axis positive side of the magnetic field coil 13b of the magnetic sensor unit 10b is connected to the common terminal (GND). Note that the X-axis positive end of the magnetic field coil 13a of the magnetic sensor unit 10a and the X-axis negative end of the magnetic coil 13b of the magnetic sensor unit 10b are connected to each other.

  Furthermore, in this example of the present embodiment, a voltage having a magnitude corresponding to the resistance change of the magnetoresistive effect elements 11 a and 11 b is applied to the magnetic field coil 13. That is, as in the above example, when the resistance values of the first and second magnetoresistive elements 11a and 11b change depending on the magnitude of the external magnetic field, a voltage corresponding to the change in the resistance value is applied to the magnetic field coil 13. A magnetic field (a canceling magnetic field) having a magnitude proportional to the voltage is formed in the direction opposite to the external magnetic field with respect to the direction of the magnetosensitive axis of each of the first and second magnetoresistive elements 11a and 11b. The The external magnetic field generated by the current I to be measured is canceled by this canceling magnetic field in the vicinity of the magnetoresistive effect element. At this time, the amount of current i flowing through the magnetic field coils 13a, 13b is proportional to the current I to be measured. Therefore, the circuit unit 15 outputs a signal representing the current amount i as an output signal. Specifically, a resistor R is connected between the other end side of the magnetic field coil 13b and the common terminal (GND), and the potential difference between both ends of the resistor R is output as a voltage signal representing the magnitude of the current amount i. What should I do?

  Also in this example, the upper magnetic field coil layers of the magnetic sensor units 10a and 10b are directed to the magnetoresistive elements 11a and 11b within a predetermined XY plane including the magnetoresistive elements 11a and 11b. The bias coil 14 is formed to be convex toward the magnetoresistive effect elements 11a and 11b in the above-mentioned range including the magnetoresistive effect elements 11a and 11b. May be.

  FIG. 8 shows a result obtained by simulating the intensity (unit: 100 μT) of the magnetic field that changes according to the distance from the surface (conductor surface) of the magnetic field coil 13 when the amount of current applied to the magnetic field coil 13 is changed. Show.

  In FIG. 8, the horizontal axis is the distance (unit: μm) on the surface of the magnetic field coil 13. As shown in FIG. 8, the magnetic field strength in the vicinity of the magnetoresistive effect elements 11a and 11b when a current of 20 mA is passed through the magnetic field coil 13 is such that the magnetoresistive effect elements 11a and 11b are located at 5 μm from the magnetic field coil 13. Sometimes it becomes 630 μT, and when it is at the position of 0.5 μm, it becomes 1500 μT (= 1.5 mT). That is, the conductor on the upper magnetic field coil layer side of the magnetic field coil 13 is brought close to the magnetoresistive effect elements 11a and 11b by 4.5 μm (a concave part of 4.5 μm is formed in the insulating layer, and the magnetic field coil 13 is electrically connected. If the projection is made to protrude toward the magnetoresistive effect elements 11a and 11b by 4.5 μm), a sufficient magnetic field can be applied to the magnetoresistive effect elements 11a and 11b with a small amount of current.

  Further, in the example of FIG. 7 in which the magnetic sensor unit 10 is paired, the circuit is not limited to the circuit illustrated in FIG. 3B, but as illustrated in FIG. 9A, the fixed resistance elements 31 and 32, the amplifier 34, It may be comprised including. Here, the fixed resistance elements 31 and 32 constitute a bridge circuit (half bridge) together with the pair of magnetoresistance effect elements 11a and 11b. Specifically, one end of the second magnetoresistive effect element 11b and one end of the fixed resistance element 32 are connected, and one end side thereof is further connected to a common terminal (GND). The one end side of the first magnetoresistive effect element 11a is connected to the other end side of the second magnetoresistive effect element 11b. Furthermore, one end side of the fixed resistance element 31 and the other end side of the fixed resistance element 32 are connected.

  The other end of the first magnetoresistance effect element 11a is connected to the other end of the fixed resistance element 31, and the other end side is further connected to the power supply terminal Vcc. Note that the circuit unit 15 may be configured by omitting the fixed resistance elements 31 and 32 in consideration of the electrical resistance of the conducting wire itself. Furthermore, instead of the fixed resistance elements 31 and 32, another pair of magnetoresistance effect elements 11c and 11d may be used (FIG. 10). In this case, another magnetic sensor 1 illustrated in FIG. 7 is used, and the magnetoresistive effect elements 11c and 11d included in the other magnetic sensor 1 are connected in place of the fixed resistance elements 31 and 32 here. Further, at this time, the magnetosensitive axis directions of the magnetoresistive effect elements 11a and 11d coincide with each other, and the magnetosensitive effect axis directions of the magnetoresistive effect elements 11c and 11b are both relative to the magnetosensitive axis direction of the magnetoresistive effect elements 11a and 11d. Assume that they are antiparallel and coincide.

  The amplifier 34 includes one end side of the first magnetoresistive effect element 11a (that is, the other end side of the second magnetoresistive effect element 11b) and one end side (that is, the fixed resistance element 32) of the fixed resistance element 31. A voltage signal corresponding to the potential difference from the other end side is supplied to one end side of the magnetic field coil 13. The other end of the magnetic field coil 13 is connected to a common terminal (GND). Specifically, the output of the amplifier 34 is connected to the end on the X-axis negative side of the magnetic field coil 13a of the magnetic sensor unit 10a (one end side of the magnetic field coil), and the magnetic field coil 13b of the magnetic sensor unit 10b. The end on the X axis positive side (the other end side of the magnetic field coil) is connected to the common terminal (GND). Note that the X-axis positive end of the magnetic field coil 13a of the magnetic sensor unit 10a and the X-axis negative end of the magnetic coil 13b of the magnetic sensor unit 10b are connected to each other.

  Further, the example of FIG. 7 in which the magnetic sensor unit 10 is paired is not limited to the circuits illustrated in FIGS. 3B and 9, and includes a fixed resistance element Rref and an amplifier 34 as illustrated in FIG. 11. You may use the circuit part 15 comprised by these. Here, the first and second magnetoresistance effect elements 11a and 11b are connected in series between the power supply terminal Vcc and the common terminal (GND). The point at which the first magnetoresistive element 11a and the second magnetoresistive element 11b are connected to each other is connected to one terminal of the amplifier 34, and the other terminal of the amplifier 34 is connected to the fixed resistor Rref. To the common terminal (GND).

  That is, the amplifier 34 outputs a voltage signal corresponding to the potential difference between the midpoint potential of the first magnetoresistive effect element 11a and the second magnetoresistive effect element 11b and the reference potential obtained by the fixed resistance element Rref. The magnetic field coil 13 is supplied to one end side. The other end of the magnetic field coil 13 is connected to a common terminal (GND).

  Further, in the example illustrated in FIG. 1 having one magnetic sensor unit 10, as in FIG. 11, as illustrated in FIG. 12, the fixed resistance element Rref, the fixed resistor 31, and the amplifier 34 are provided. The circuit unit 15 configured to be included may be used. Here, the magnetoresistive effect element 11 and the fixed resistor 31 are connected in series between the power supply terminal Vcc and the common terminal (GND). The point where the magnetoresistive effect element 11 and the fixed resistor 31 are connected to each other is connected to one terminal of the amplifier 34, and the other terminal of the amplifier 34 is connected to the common terminal (GND) via the fixed resistance element Rref. It is connected to the.

  That is, the amplifier 34 outputs a voltage signal corresponding to the potential difference between the midpoint potential of the magnetoresistive effect element 11 and the fixed resistor 31 and the reference potential obtained by the fixed resistance element Rref on one end side of the magnetic field coil 13. To supply. The other end of the magnetic field coil 13 is connected to a common terminal (GND).

  DESCRIPTION OF SYMBOLS 1 Magnetic sensor apparatus, 10 Magnetic sensor part, 11 Magnetoresistive element, 12 Magnetic body, 13 Magnetic field coil, 14 Bias coil, 15 Circuit part, 20 Substrate, 21 Lower magnetic field coil layer, 22 Magnetic material layer, 23 Upper magnetic field coil Layer, 24 bias coil layer, 31, 32, 33 fixed resistance element, 34 amplifier.

Claims (3)

A magnetoresistive element;
A pair of magnetic bodies disposed across the magnetoresistive element; and
A magnetic field coil wound around the pair of magnetic bodies and forming a magnetic field to the magnetoresistive element;
Is a magnetic sensor device formed on a substrate,
The magnetic field coil includes a conductor pattern disposed on each of a lower magnetic field coil layer and an upper magnetic field coil layer that are stacked with the magnetic material interposed therebetween.
The upper magnetic field coil layer is a magnetic sensor device that is close to a formation surface of the lower magnetic field coil layer at a position where the magnetoresistive effect element is disposed. First and second magnetoresistive elements that are arranged in a direction orthogonal to the magnetosensitive axis direction, the magnetosensitive axis directions being antiparallel to each other;
A pair that is mainly disposed in a layer different from the layer including the first and second magnetoresistive elements, and is opposed to each other with a gap disposed at a position corresponding to the arrangement of the first magnetoresistive elements. A first magnetic body, and a magnetic layer including a pair of second magnetic bodies disposed opposite to each other with a gap disposed at a position corresponding to the position of the second magnetoresistive element;
Winding around each of the pair of first magnetic bodies and each of the pair of second magnetic bodies in a direction intersecting with the magnetosensitive axis direction of the magnetoresistive element, with the magnetic layers sandwiched therebetween. A lower magnetic field coil layer and an upper magnetic field coil layer, each including a magnetic field coil conductor to be rotated;
Have
The upper magnetic field coil layer is a magnetic sensor device that is close to the formation surface of the lower magnetic field coil layer within a predetermined range including the magnetoresistive effect element. The magnetic sensor device according to claim 2,
A spiral bias coil is disposed in a bias coil layer disposed through an insulating layer with respect to the upper magnetic field coil layer over a range overlapping the range in which the first and second magnetic bodies are disposed. Magnetic sensor device.

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