JP4735304B2 - Triaxial magnetic sensor and manufacturing method thereof - Google Patents

Description

  In the present invention, an X-axis sensor in which a plurality of giant magnetoresistive elements are bridge-connected, a Y-axis sensor in which a plurality of giant magnetoresistive elements are bridge-connected, and a plurality of giant magnetoresistive elements are bridge-connected The present invention relates to a three-axis magnetic sensor provided with a Z-axis sensor in one substrate and a method for manufacturing the same.

  Conventionally, giant magnetoresistive elements (GMR elements), magnetic tunnel effect elements (TMR elements), and the like are known as elements used in magnetic sensors. These magnetoresistive elements include a pinned layer whose magnetization direction is pinned (fixed) in a predetermined direction, and a free layer whose magnetization direction changes according to an external magnetic field. A resistance value corresponding to the relative relationship between the direction and the magnetization direction of the free layer is shown as an output. As a magnetic sensor using such a magnetoresistive effect element, for example, Patent Document 1 (Japanese Patent No. 3498737) and Patent Document 2 (Japanese Patent Laid-Open No. 2002-299728) have been proposed.

  In the magnetic sensors proposed in Patent Document 1 and Patent Document 2, the magnetoresistive elements are orthogonal to each other so as to detect magnetic field changes in two orthogonal directions (X-axis direction and Y-axis direction). In order to detect an external magnetic field in a two-dimensional plane by obtaining an output (change in resistance value) of each element by bridging each element as a group of several elements. .

By the way, there is a case where it is necessary to obtain a direction in space, that is, a direction in three dimensions, instead of a two-dimensional plane. In such an application, it is necessary to accurately determine the magnetic direction in three dimensions (X-axis direction, Y-axis direction, and Z-axis direction). However, since such a three-dimensional magnetic sensor capable of obtaining the orientation in three dimensions cannot be manufactured on the same substrate, a thin three-dimensional magnetic sensor has not been obtained at the present time.
Japanese Patent No. 3498737 JP 2002-299728 A

  Therefore, a three-axis magnetic sensor (three-dimensional magnetic sensor) in which two chips are mounted in an inclined manner has been proposed. In this three-axis magnetic sensor, as shown in the top view of FIG. 20A, two chips consisting of a square A chip and a B chip in a plan view are mounted in a package. Then, as shown in the side view of FIG. 20B, these two chips are arranged at an angle θ from the horizontal plane, and the A chip has an x-axis sensor (ad) and a y1-axis. Sensors (e to h) are built in, and y2 axis sensors (i to l) are built in the B chip. Each sensor is composed of four GMR elements (ad, e to h, i to l), and each GMR element is formed along the side of the chip.

  In this case, as shown in FIG. 21A, the GMR elements a to d are bridge-connected to constitute an x-axis sensor. Further, as shown in FIG. 21 (b), the Y1-axis sensor is configured by bridge-connecting the GMR elements e to h. Furthermore, as shown in FIG. 21 (c), the GMR elements i to l are bridge-connected to form a y2-axis sensor. The sensitivity directions of the GMR elements a to d constituting the x axis sensor are the x axis direction, the sensitivity directions of the GMR elements e to h constituting the y1 axis sensor are the y1 axis direction, and the GMR elements constituting the y2 axis sensor. The sensitivity directions i to l are set in the y2 axis direction.

  Thereby, when a magnetic field is applied to the GMR elements constituting each sensor in the direction of the arrow in FIG. 20A, the resistance value decreases in proportion to the magnetic field strength. On the other hand, when a magnetic field is applied in the direction opposite to the arrow direction in FIG. 20A, the resistance value increases in proportion to the magnetic field strength. Here, each GMR element is bridge-connected as shown in FIGS. 21A, 21B, and 21C to form each sensor, and when a predetermined voltage (for example, 3 V) is applied between the power source and the ground, x Sx is output from the axis sensor, Sy1 is output from the y1-axis sensor, and Sy2 is output from the y2-axis sensor.

Based on the obtained output, the magnetic field component Hx in the x-axis direction can be obtained by the following equation (1). Similarly, the magnetic field component Hy in the y-axis direction can be obtained from the following equation (2), and the magnetic field component Hz in the z-axis direction can be obtained from the following equation (3).
Hx = 2kx × Sx (1)
Hy = ky (Sy1-Sy2) / cos θ (2)
Hz = kz (Sy1 + Sy2) / sin θ (3)
However, kx, ky, kz are proportional constants, and if the sensitivity of each sensor is equal, kx = ky = kz.

However, in the above-described three-axis magnetic sensor, since it is necessary to mount two chips consisting of an A chip and a B chip in the package, it is complicated and time-consuming to manufacture this type of sensor. Caused a problem. In addition, since it is necessary to use a special package, this type of sensor is expensive and difficult to downsize.
Accordingly, the present invention has been made to solve such problems, and an object thereof is to provide a three-axis magnetic sensor having a structure that can be easily and easily manufactured in one chip (one substrate). To do.

  In order to achieve the above object, a three-axis magnetic sensor of the present invention includes an X-axis sensor in which a plurality of giant magnetoresistance effect elements are bridge-connected, and a Y-axis sensor in which a plurality of giant magnetoresistance effect elements are bridge-connected. A Z-axis sensor in which a plurality of giant magnetoresistance effect elements are bridge-connected is provided in one substrate. The giant magnetoresistive element is formed of at least one giant magnetoresistive element bar, and the giant magnetoresistive element of the X-axis sensor is formed on a plane parallel to the plane of the substrate. The longitudinal direction of the giant magnetoresistive effect element bar is the Y-axis direction, and the magnetization direction of the pinned layer of the giant magnetoresistive effect element bar is a predetermined angle (desirably 45 °) with respect to the X axis. The sensitivity direction is perpendicular to the longitudinal direction of the giant magnetoresistive element bar, and the giant magnetoresistive element of the Y-axis sensor is formed on a plane parallel to the plane of the substrate. The longitudinal direction of the giant magnetoresistive effect element bar is the X-axis direction, and the magnetization direction of the pinned layer of the giant magnetoresistive effect element bar is a predetermined angle (preferably 45 °) with respect to the Y axis. And that The direction of sensitivity is perpendicular to the longitudinal direction of each giant magnetoresistive element bar, and the giant magnetoresistive element of the Z-axis sensor is formed on a slope provided on the substrate, and the direction of magnetization is within the slope. The sensitivity direction is formed so as to intersect with the longitudinal direction of the giant magnetoresistive effect element bar.

  As a result, the sensitivity directions of the giant magnetoresistive elements of the X-axis sensor, the Y-axis sensor, and the Z-axis sensor are formed so as to intersect each other in the three-dimensional direction. An accurate magnetic field in the three-dimensional direction can be measured. Since the X-axis sensor, the Y-axis sensor, and the Z-axis sensor are provided in one substrate, it is possible to prevent the occurrence of angular deviation as in a magnetic sensor formed by assembling separate sensors. In addition, an increase in the size of the sensor can be prevented, and a small three-axis magnetic sensor can be provided. In this case, since the Z-axis sensor is only formed on the slope provided on the substrate, the Z-axis sensor can be easily and easily manufactured in one substrate. Here, in the giant magnetoresistive effect element, a plurality of giant magnetoresistive effect element bars are arranged in parallel, and when adjacent giant magnetoresistive effect element bars are connected in series by a bias magnet film, A bias magnetic field can be easily applied to the free layer of the effect element bar.

  In this case, each giant magnetoresistive effect element bar constituting the giant magnetoresistive effect element of the Z-axis sensor is formed on a slope formed to face each other at the same angle with respect to the Z axis perpendicular to the plane of the substrate. The longitudinal direction of the giant magnetoresistive effect element bar is 45 ° with respect to the X-axis direction or the Y-axis of the substrate, and giant magnetism constituted by giant magnetoresistive effect element bars respectively formed on each inclined surface. If the resistance effect elements are adjacent to each other and arranged in parallel with each other, the X-axis component and the Y-axis component of the magnetic field sensitivity are canceled in each giant magnetoresistive effect element. Only the Z-axis component will appear. In the three-axis magnetic sensor configured as described above, it is desirable for miniaturization that the substrate is formed in a rectangular shape or a square shape having an aspect ratio of 1: 2 or 1: 1.5 in plan view.

In order to manufacture the above-described three-axis magnetic sensor, a plurality of giant magnetoresistive elements that serve as X-axis sensors, a plurality of giant magnetoresistive elements that serve as Y-axis sensors, a Z-axis sensor, The giant magnetoresistive effect element forming step for forming a plurality of giant magnetoresistive effect elements, and the two magnetoresistive effect elements in a bridge-connected set of the magnetoresistive effect elements formed on the substrate are different from each other. may be such and an ordering heat treatment step of heating the heat-treated at the same time ordering each of the magnetoresistive element while applying a magnetic field can. In this case, in the regularized heat treatment step, the bars of the bar magnet array in which a plurality of bar magnets are arranged in parallel so that the polarities of the bar magnets adjacent to each other on the substrate on which each giant magnetoresistive element is formed are alternately different. It is desirable that the magnets are arranged so that the arrangement direction of the magnets forms an angle of 45 ° with the substrate, and then the heat treatment is performed by heating.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings as a triaxial magnetic sensor of Example 1 and a triaxial magnetic sensor of Example 2, but the present invention is not limited to these Examples. However, the present invention can be appropriately modified and implemented without changing the object of the present invention.

1. Example 1
First, the triaxial magnetic sensor of Example 1 is demonstrated below based on FIGS. FIG. 1 is a schematic configuration diagram schematically showing the three-axis magnetic sensor of Example 1, FIG. 1 (a) is a plan view, and FIG. 1 (b) is A in FIG. 1 (a). It is sectional drawing which shows -A 'cross section. FIG. 2 is a diagram schematically showing a schematic configuration of a giant magnetoresistive effect element used in the triaxial magnetic sensor of the present invention. FIG. 2A shows a plurality of giant magnetoresistive effect element (GMR) bars. FIG. 2 (b) is a cross-sectional view schematically showing a BB ′ cross section of FIG. 2 (a), showing a state in which one giant magnetoresistive effect element is configured by being connected; FIG.2 (c) is a figure which shows typically the lamination | stacking state inside FIG.2 (b).

  3 is a diagram schematically showing the pinning direction and sensitivity direction of the three-axis magnetic sensor of FIG. 1, and FIG. 3 (a) is a plan view schematically showing the entire plane, and FIG. 3 (b). FIG. 3 is a perspective view schematically showing an enlarged C part of FIG. 3A, and FIG. 3C is a perspective view schematically showing an enlarged D part of FIG. . 4 is a block diagram showing the bridge connection, FIG. 4 (a) is a block diagram showing the bridge connection of the X-axis sensor, and FIG. 4 (b) is a block diagram showing the bridge connection of the Y-axis sensor. FIG. 4C is a block diagram showing the bridge connection of the Z-axis sensor. 5-14 is sectional drawing which shows typically the triaxial magnetic sensor of Example 1 in the middle of manufacture. FIG. 15 is a diagram showing a regularized heat treatment (pinning process), FIG. 15A is a perspective view schematically showing a bar magnet array used for the regularized heat treatment (pinning process), and FIG. It is a top view which shows typically the state of regularization heat processing (pinning process).

  As shown in FIG. 1, the triaxial magnetic sensor 10 according to the first embodiment has a rectangular shape (here, a short side (longitudinal) and a long side) having sides along the X axis and the Y axis that are orthogonal to each other in a plan view. (Horizontal) ratio (aspect ratio) is 1: 2, the side along the X axis is the long side, and the side along the Y axis is the short side). A substrate 11 made of quartz or silicon having a small thickness in the Z-axis direction orthogonal to the Y-axis is provided. A total of 12 GMR elements each including four X-axis GMR elements 12a to 12d, Y-axis GMR elements 12e to 12h, and Z-axis GMR elements 12i to 12l are formed on the substrate 11, and a pad portion. (Portion from which the output is extracted from the wiring: not shown) and a via portion (a portion connected to the wiring from the GMR element, this via portion is not finally exposed: not shown) and wiring (not shown) Z) is built. Note that an LSI and a wiring layer are built in the substrate 11, and those using the substrate on which the LSI is built are a digital output magnetic sensor, and only the wiring layer is built. The one using the substrate is an analog output magnetic sensor.

  Here, the X-axis GMR element includes a first X-axis GMR element 12a, a second X-axis GMR element 12b, a third X-axis GMR element 12c, and a fourth X-axis GMR element 12d. Then, the left end portion of the X axis of the substrate 11 (in this case, the left end portion of FIG. 1A is used as the X axis reference point, the direction from the reference point toward the right side of the drawing is the X axis positive direction, The opposite direction is the negative X-axis direction (the same is true in the following) and the substantially central portion (hereinafter referred to as the X-axis central portion) of the right-side end portion and the lower end portion of the Y-axis (in this case, 1A is the Y-axis reference point, the direction from the reference point toward the upper side of the figure is the Y-axis positive direction, and the opposite direction is the Y-axis negative direction. The first X-axis GMR element 12a is disposed above a substantially central part (hereinafter referred to as the Y-axis central part) between the upper end and the second X-axis GMR element 12b. In addition, in the vicinity of the left end of the X axis of the substrate 11, a third X axis GMR element 12c is disposed above the Y axis center, and a fourth X axis GMR element 12d is disposed below the third X axis GMR element 12d.

  The Y-axis GMR element includes a first Y-axis GMR element 12e, a second Y-axis GMR element 12f, a third Y-axis GMR element 12g, and a fourth Y-axis GMR element 12h. The first Y-axis GMR element 12e is arranged in the vicinity of the upper end of the Y-axis of the substrate 11 at the right side of the substantially middle part from the X-axis central part to the left-side end, and the second Y-axis GMR element 12f is arranged on the left side. Is arranged. Further, in the vicinity of the lower end of the Y axis of the substrate 11, a third Y axis GMR element 12 g is arranged on the right side of the substantially middle part from the X axis central part to the left end, and the fourth Y axis GMR element is located on the left side. 12h is arranged.

  Further, the Z-axis GMR element includes a first Z-axis GMR element 12i, a second Z-axis GMR element 12j, a third Z-axis GMR element 12k, and a fourth Z-axis GMR element 12l. The first Z-axis GMR element 12i is arranged at a substantially intermediate portion from the Y-axis central portion of the substrate 11 to the lower end portion of the Y-axis, and at a left of a substantially intermediate portion from the X-axis central portion to the right end portion, A second Z-axis GMR element 12j is disposed at the lower right. A third Z-axis GMR element 12k is arranged at a substantially intermediate portion from the Y-axis central portion of the substrate 11 to the upper end portion of the Y-axis, and to the left of a substantially intermediate portion from the X-axis central portion to the left end portion. A fourth Z-axis GMR element 121 is arranged at the lower right.

  Here, each of the GMR elements 12a to 12d, 12e to 12h, and 12i to 12l is an even number arranged in parallel and adjacent to each other in a strip shape (in this case, for example, the number is preferably four and is preferably an even number, Any number of GMR bars may be used as long as there are two or more). These GMR bars are connected in series by a magnet film (bias magnet film), and a magnet film serving as a terminal portion is connected to these end portions. Is formed. For example, as shown in FIG. 2 (in FIG. 2, only the first X-axis GMR element 12a is shown, but the other GMR elements have the same configuration), four GMR bars 12a-1, 12a-2, 12a-3, 12a-4 are connected in series by magnet films 12a-6, 12a-7, 12a-8, and magnet films 12a-5, 12a-9 serving as terminal portions are connected to these ends. Has been formed.

  In this case, each GMR bar (12a-1, 12a-2, 12a-3, 12a-4, etc.) of the X-axis GMR elements 12a to 12d is formed on a plane parallel to the surface of the substrate 11, They are arranged so that the longitudinal direction is parallel to the Y axis (perpendicular to the X axis). The GMR bars of the Y-axis GMR elements 12e to 12h are formed on a plane parallel to the surface of the substrate 11, and are arranged so that the longitudinal direction is parallel to the X-axis (perpendicular to the Y-axis). The X-axis GMR elements 12a to 12d are arranged so as to be orthogonal to the longitudinal direction of each GMR bar. Further, each GMR bar of the Z-axis GMR elements 12i to 12l has one inclined surface (inclination angle) on each inclined surface of a plurality of protrusions (bank portions) 15 having a trapezoidal cross-sectional shape formed on the substrate 11. 1 GMR bar (for example, 12k-1, 12k-2, 12k-3, 12k-4, or 12l-1, 12l-2 shown in FIG. 1B). , 12l-3, 12l-4, etc.) are formed so that the longitudinal direction is 45 ° with respect to the X axis (Y axis).

  Next, the configuration of the GMR bar will be described with reference to FIG. 2, taking the GMR bar 12a-2 of the first X-axis GMR element 12a as an example. Since the other GMR bars 12a-1, 12a-3, and 12a-4 are equal to this, only the GMR bar 12a-1 will be described here. Also, the configurations of the respective GMR bars of the other X-axis GMR elements 12b, 12c, 12d, Y-axis GMR elements 12e, 12f, 12g, 12h and Z-axis GMR elements 12i, 12j, 12k, 12l are the same. The description is omitted.

  Here, the GMR bar 12a-2 of the first X-axis GMR element 12a is as shown in FIG. 2B, which is a schematic sectional view cut along a plane along the line BB ′ in FIG. Further, it is a hard ferromagnetic material such as CoCrPt formed of a spin valve film SV arranged so that its longitudinal direction is parallel to the Y-axis, and has a high coercive force, which is formed below both ends. Magnet films (bias magnet films; hard ferromagnetic thin film layers) 12a-6 and 12a-7. As shown in FIG. 2C, the spin valve film SV has a free layer (free layer, free magnetic layer) F sequentially stacked on the substrate 11, and a film thickness of 2.4 nm (24 cm). A conductive spacer layer S made of Cu, a pinned layer (pinned layer, fixed magnetic layer) P, and a capping layer C made of titanium (Ti) or tantalum (Ta) having a thickness of 2.5 nm (25 mm). ing.

  The free layer F is a layer in which the direction of magnetization changes according to the direction of the external magnetic field. The CoZrNb amorphous magnetic layer 12a-21 having a film thickness of 8 nm (80 cm) formed immediately above the substrate 11 and the CoZrNb amorphous magnetic layer. The NiFe magnetic layer 12a-22 having a thickness of 3.3 nm (33Å) formed on the layer 12a-21 and the thickness of about 1 to 3 nm (10 to 30Å) formed on the NiFe magnetic layer 12a-22. It consists of a CoFe layer 12a-23 having a thickness. The CoZrNb amorphous magnetic layer 12a-21 and the NiFe magnetic layer 12a-22 constitute a soft ferromagnetic thin film layer. The CoFe layer 12a-23 is provided to prevent diffusion of Ni in the NiFe layer 12a-22 and Cu12a-24 in the spacer layer S.

  The pinned layer P is composed of a CoFe magnetic layer 12a-25 having a thickness of 2.2 nm (22 Å) and an antiferromagnetic film 12a-26 having a thickness of 24 nm (240 し た) formed from a PtMn alloy containing 45 to 55 mol% of Pt. Are superimposed. The CoFe magnetic layer 12a-25 is exchange-coupled to the magnetized (magnetized) antiferromagnetic film 12a-26 so that the direction of magnetization (magnetization vector) is 45 ° with respect to the positive X-axis direction. It constitutes a pinned layer that is pinned (fixed) in the direction (direction of solid arrow a1 in FIG. 3A).

  Note that the bias magnet films 12a-5, 12a-6, 12a-7, 12a-8, and 12a-9 of the first X-axis GMR element 12a described above maintain the uniaxial anisotropy of the free layer F. A bias magnetic field is applied to the layer F in the longitudinal direction of each GMR bar and in a direction that forms an acute angle with the magnetization (magnetization vector) direction of the pinned layer. The CoFe magnetic layer 12a-25 (the same applies to the other GMR bars 12a-1, 12a-3, 12a-4) is exchange coupled to the magnetized (magnetized) antiferromagnetic film 12a-26. The pinned layer is pinned (fixed) so that the direction of magnetization (magnetization vector) is pinned (fixed) in the direction of 45 ° with respect to the positive direction of the X axis (the direction of the solid arrow a1 in FIG. 3A). Is formed. Similarly, the bias magnet film of the second X-axis GMR element 12b is biased with respect to the free layer F of each GMR bar in the longitudinal direction of each GMR bar and in an acute angle with the direction of magnetization (magnetization vector) of the pinned layer. Giving a magnetic field. The pinned layer is formed so that the direction of magnetization (magnetization vector) is pinned (fixed) in a direction of 45 ° with respect to the positive direction of the X axis (the direction of the solid line arrow b1 in FIG. 3A).

  As a result, the sensitivity directions (magnetic field sensitivity directions) of the first X-axis GMR element 12a and the second X-axis GMR element 12b are perpendicular to the longitudinal direction of each GMR bar, that is, the X-axis positive direction (see FIG. 3 (a) (in the direction of dotted arrows a2 and b2), and when a magnetic field is applied in the directions of dotted arrows a2 and b2 in FIG. 3 (a), the first X-axis GMR element 12a and the second X-axis GMR element 12b The resistance value decreases in proportion to the magnitude of the magnetic field, and the first X-axis GMR element 12a and the second X-axis GMR element when a magnetic field is applied in the direction opposite to the directions of the dotted arrows a2 and b2 in FIG. The resistance value of 12b increases in proportion to the magnitude of the magnetic field.

  On the other hand, in the third X-axis GMR element 12c and the fourth X-axis GMR element 12d, the bias magnet film has a magnetization direction (magnetization vector) of the pinned layer in the longitudinal direction of each GMR bar with respect to the free layer F of each GMR bar. A bias magnetic field is applied in a direction that forms an acute angle with the direction (that is, a direction opposite to the bias magnetic field of the first X-axis GMR element 12a and the second X-axis GMR element 12b by 180 °). Then, the direction of magnetization (magnetization vector) is −45 ° with respect to the negative X-axis direction (in the directions of solid arrows c1 and d1 in FIG. 3A), the first X-axis GMR element 12a and the second X-axis GMR element 12b. The pinned layer is formed so as to be pinned (fixed) in a direction 180 ° opposite to the magnetization direction of the pinned layer.

  As a result, the sensitivity directions of the third X-axis GMR element 12c and the fourth X-axis GMR element 12d are perpendicular to the longitudinal direction of each GMR bar, that is, in the directions of the dotted arrows c2 and d2 in FIG. 1X-axis GMR element 12a and second X-axis GMR element 12b are in the direction opposite to the sensitivity direction by 180 °, and when a magnetic field is applied in the directions of dotted arrows c2 and d2 in FIG. The resistance values of the element 12c and the fourth X-axis GMR element 12d decrease in proportion to the magnitude of the magnetic field, and when the magnetic field is applied in the direction opposite to the dotted arrows c2 and d2 in FIG. The resistance values of the GMR element 12c and the fourth X-axis GMR element 12d increase in proportion to the magnitude of the magnetic field.

  Further, in the first Y-axis GMR element 12e and the second Y-axis GMR element 12f, the bias magnet film has a magnetization direction (magnetization vector) of the pinned layer in the longitudinal direction of each GMR bar with respect to the free layer F of each GMR bar. A bias magnetic field is applied in a direction that forms an acute angle with the direction (that is, the direction opposite to the direction in which the bias magnetic fields of the first X-axis GMR element 12a and the second X-axis GMR element 12b are rotated 90 ° counterclockwise). Then, the pinned layer is formed so that the direction of magnetization (magnetization vector) is pinned (fixed) in the direction of 45 ° with respect to the positive direction of the Y-axis (the directions of solid arrows e1 and f1 in FIG. 3A). Yes.

  Thus, the sensitivity directions of the first Y-axis GMR element 12e and the second Y-axis GMR element 12f are perpendicular to the longitudinal direction of each GMR bar, that is, the Y-axis positive direction (dotted arrow e2 in FIG. 3A). , F2 direction), and when a magnetic field is applied in the directions of the dotted arrows e2, f2 in FIG. 3A, the resistance values of the first Y-axis GMR element 12e and the second Y-axis GMR element 12f become the magnitude of the magnetic field. When a magnetic field is applied in the direction opposite to the dotted arrows e2 and f2 in FIG. 3A, the resistance value of the first Y-axis GMR element 12e and the second Y-axis GMR element 12f is the magnitude of the magnetic field. It will increase in proportion to.

  On the other hand, in the third Y-axis GMR element 12g and the fourth Y-axis GMR element 12h, the bias magnet film has a magnetization direction (magnetization vector) of the pinned layer in the longitudinal direction of each GMR bar with respect to the free layer F of each GMR bar. A bias magnetic field is applied in a direction that forms an acute angle with the direction (that is, a direction opposite to the bias magnetic field of the first Y-axis GMR element 12e and the second Y-axis GMR element 12f by 180 °). Then, a pinned layer is formed so that the direction of magnetization (magnetization vector) is pinned (fixed) in the direction of −45 ° with respect to the negative Y-axis direction (the directions of solid arrows g1 and h1 in FIG. 3A). ing.

  Thereby, the sensitivity directions of the third Y-axis GMR element 12g and the fourth Y-axis GMR element 12h are perpendicular to the longitudinal direction of each GMR bar, that is, the Y-axis negative direction (dotted arrow g2 in FIG. 3A). , H2 direction, and a direction opposite to the sensitivity direction of the first Y-axis GMR element 12e and the second Y-axis GMR element 12f by 180 °), and a magnetic field is applied in the directions of the dotted arrows g2 and h2 in FIG. In addition, the resistance values of the third Y-axis GMR element 12g and the fourth Y-axis GMR element 12h decrease in proportion to the magnitude of the magnetic field, and a magnetic field is applied in the direction opposite to the dotted arrows g2 and h2 in FIG. In this case, the resistance values of the third Y-axis GMR element 12g and the fourth Y-axis GMR element 12h increase in proportion to the magnitude of the magnetic field.

  In the first Z-axis GMR element 12i and the second Z-axis GMR element 12j, as schematically shown in FIG. 3B, bias magnet films 12i-6, 12i-7, 12i-8 (12j-6, 12j-7, 12j-8) are parallel to the longitudinal direction of each GMR bar 12i-1, 12i-2, 12i-3, 12i-4 (12j-1, 12j-2, 12j-3, 12j-4). X, which is the longitudinal direction on the plane of each inclined surface (inclination angle is approximately 45 °) of the projection (bank portion) 15, that is, a direction that forms an acute angle with the direction of the magnetization (magnetization vector) of the pinned layer. A bias magnetic field is applied in a direction that is at an angle of 45 ° with respect to the axis and the Y-axis and the direction of magnetization (magnetization vector) of the pinned layer. Then, a pinned layer is formed so that the direction of magnetization (magnetization vector) is pinned (fixed) in a direction of 45 ° with respect to the positive direction of the Z-axis (direction of solid arrow i1 (j1) in FIG. 3B). ing.

  These GMR bars 12i-1, 12i-2, 12i-3, 12i-4 (12j-1, 12j-2, 12j-3, 12j-4) are bias magnet films 12i-6, 12i-7. , 12i-8 (12j-6, 12j-7, 12j-8). As a result, the x-axis component and the y-axis component are cancelled. Therefore, the sensitivity directions of the first Z-axis GMR element 12i and the second Z-axis GMR element 12j are perpendicular to the longitudinal direction of each GMR bar. , The Z-axis positive direction, that is, the direction indicated by the dotted arrow i2 (j2) in FIG. 3B (the direction from the back of the paper to the front). When a magnetic field is applied in the direction of the dotted arrow i2 (j2) in FIG. 3B, the resistance values of the first Z-axis GMR element 12i and the second Z-axis GMR element 12j decrease in proportion to the magnitude of the magnetic field. When a magnetic field is applied in the direction opposite to the dotted arrow i2 (j2) in FIG. 3B, the resistance values of the first Z-axis GMR element 12i and the second Z-axis GMR element 12j are proportional to the magnitude of the magnetic field. Will increase.

  On the other hand, in the third Z-axis GMR element 12k and the fourth Z-axis GMR element 12l, as schematically shown in FIG. 3C, the bias magnet films 12k-6, 12k-7, 12k-8 (12l-6, 12l-7, 12l-8) are parallel to the longitudinal direction of each GMR bar 12k-1, 12k-2, 12k-3, 12k-4 (12l-1, 12l-2, 12l-3, 12l-4). X, which is the longitudinal direction on the plane of each inclined surface (inclination angle is approximately 45 °) of the projection (bank portion) 15, that is, a direction that forms an acute angle with the direction of the magnetization (magnetization vector) of the pinned layer. A bias magnetic field is applied in a direction that is at an angle of 45 ° with respect to the axis and the Y-axis and the direction of magnetization (magnetization vector) of the pinned layer. Then, the pinned layer is formed so that the direction of magnetization (magnetization vector) is pinned (fixed) in a direction of 45 ° with respect to the negative Z-axis direction (the direction of the solid line arrow k1 (l1) in FIG. 3C). ing.

  These GMR bars 12k-1, 12k-2, 12k-3, 12k-4 (12l-1, 12l-2, 12l-3, 12l-4) are bias magnet films 12k-6, 12k-7. , 12k-8 (12l-6, 12l-7, 12l-8). As a result, the x-axis component and the y-axis component are canceled, and the sensitivity directions of the third Z-axis GMR element 12k and the fourth Z-axis GMR element 12l are perpendicular to the longitudinal direction of each GMR bar. , In the negative direction of the Z-axis, that is, in the direction of k2 (l2) of the dotted arrow in FIG. 3C (the direction from the front to the back of the page), and in the direction of the dotted arrow k2 (l2) in FIG. Is applied, the resistance values of the third Z-axis GMR element 12k and the fourth Z-axis GMR element 12l decrease in proportion to the magnitude of the magnetic field, and are in the direction opposite to the dotted arrow k2 (l2) in FIG. When a magnetic field is applied to the third Z-axis GMR element 12k and the fourth Z-axis GMR element 12l, the resistance values increase in proportion to the magnitude of the magnetic field.

  The X-axis magnetic sensor is shown in FIG. 4A (in FIGS. 4A to 4C, each arrow indicates that the magnetization direction is upward when the pinned layer of each GMR element is pinned. 1), the first to fourth X-axis GMR elements 12a to 12d are connected by full bridge connection. In such a configuration, the pad 13a and the pad 13b are connected to the positive electrode and the negative electrode of the constant voltage source 14, and are given a potential Vxin + (3 V in this example) and a potential Vxin- (0 (V) in this example). Then, the potentials of the pad 13c and the pad 13d are taken out as the potential Vxout + and the potential Vxout-, respectively, and the potential difference (Vxout + −Vxout−) is taken out as the sensor output Vxout.

  The Y-axis magnetic sensor is configured by full-bridge connection of the first to fourth Y-axis GMR elements 12e to 12h, as shown in an equivalent circuit in FIG. The pad 13e and the pad 13f are connected to the positive electrode and the negative electrode of the constant voltage source 14, and are supplied with a potential Vyin + (3V in this example) and a potential Vyin− (0 (V) in this example), and the pad 13g and the pad 13h. Is taken out as a sensor output Vyout.

  The Z-axis magnetic sensor is configured by full-bridge connection of the first to fourth Z-axis GMR elements 12i to 12l as shown in an equivalent circuit in FIG. The pad 13i and the pad 13j are connected to the positive electrode and the negative electrode of the constant voltage source 14, and the potential Vzin + (3V in this example) and the potential Vzin− (0 (V) in this example) are applied. Is extracted as a sensor output Vzout.

  Next, a method for manufacturing a triaxial magnetic sensor having the above-described configuration will be described below based on schematic cross-sectional views in FIGS. 5 to 14, (a) shows a via portion, (b) shows a pad portion, and (c) shows a Z-axis GMR portion. In this case, as described above, as the substrate 11, it is desirable to use a substrate in which an LSI has been fabricated in advance by a CMOS process or a substrate in which only a wiring layer has been fabricated in advance.

In this method of manufacturing a triaxial magnetic sensor, as shown in FIG. 5, first, an interlayer insulating film (SOG: Spin On Glass) 11b is formed on a substrate (quartz substrate or silicon substrate) 11 on which a wiring layer 11a is formed. Flatten by coating. Thereafter, as shown in FIG. 6, the interlayer insulating film 11b on the via portion and the pad portion is removed by etching, and openings 11c and 11d are formed. Next, as shown in FIG. 7, an oxide film (thickness: 1500 mm) 11e made of, for example, a SiO ₂ film and a nitride film (thickness: 5000 mm) 11f made of, for example, a Si ₃ N ₄ film are formed on these surfaces by plasma CVD. A film was formed. Next, a resist was applied on these and cut into a pattern that formed openings in the via part and the pad part.

  Next, as shown in FIG. 8, the nitride film 11f on the via part and the pad part was removed by etching, and then the resist was removed. As a result, openings 11g and 11h are formed in the nitride film 11f on the via part and the pad part, but the oxide film 11e is left without being etched. In this case, the opening width (diameter) of the openings 11g and 11h is made smaller than the opening width (diameter) of the openings 11c and 11d. This is to prevent the interlayer insulating film 11b from being exposed in the openings 11c and 11d and preventing moisture from entering the wiring layer and the LSI.

Thereafter, as shown in FIG. 9, an upper oxide film (thickness: 5 μm) 11i made of, for example, a SiO ₂ film was formed thereon by plasma CVD. Next, a resist was applied on these to form a resist film (thickness: 5 μm) 11j. Then, a pattern for forming openings in the via portion and the pad portion is cut in the formed resist film (thickness: 5 μm) 11j, and projections for arranging the Z-axis GMR elements 41, 42, 43, 44 ( The pattern for forming the (bank portion) 15 was cut. After cutting, heat treatment was performed at a temperature of 150 ° C. for 10 minutes to form a tapered portion of the resist 11j in a tapered shape (tapered) as shown in FIG.

  Thereafter, the upper oxide film (thickness: 5 μm) 11i and the resist film (thickness: 5 μm) 11j are etched at substantially the same ratio, and a thickness of about 5000 mm remains at the maximum thickness portion of the upper oxide film 11i after etching. Dry etching was performed under various conditions. At this time, the opening width (diameter) at the via portion and the pad portion of the upper oxide film 11i was not made larger than the opening width (diameter) at the via portion and the pad portion of the nitride film 11f. After dry etching, the remaining resist was removed. As a result, as shown in FIG. 11, a protrusion (bank portion) 15 made of the upper oxide film 11i is formed in the GMR portion.

  Next, a resist was applied on these, and the resist was cut into a pattern for forming an opening in the via portion, and then etched. Thereafter, by removing the remaining resist, as shown in FIG. 12, an opening 11k was formed in the via portion, and the uppermost wiring layer 11a of the substrate 11 was exposed. Next, a base film made of Ti or Cr (film thickness: 300 μm) was formed by sputtering.

  Next, a bias magnet film 11m having a high coercive force made of a hard ferromagnetic material such as CoCrPt (later, for example, 12a-5, 12a-6, 12a-7, 12a-8, 12a shown in FIG. 2A). −9 etc.) was formed on the surface of the base film by sputtering, vacuum deposition, ion plating, or the like. A resist was applied on the base film and the bias magnet film 11m, the resist was cut into a bias magnet film pattern, and then the bias magnet film 11m and the base film were etched. In this case, since the resist is exposed on the upper surface of the substrate, the pattern is formed on the slope, so that using the mask as it is reduces the patterning accuracy. It is desirable that the resist on the protrusion is tapered and then etched. Thereafter, the remaining resist was removed. Next, a GMR multilayer film 11n (later 12a to 12d, 12e to 12h, 12i to 12l, etc.) forming a GMR element was formed on the surface of the base film and the bias magnet film 11m by sputtering.

  As shown in FIG. 2C, the GMR multilayer film 11n has a free layer (free layer, free magnetic layer) F sequentially stacked on the substrate 11, and a film thickness of 2.4 nm (24 cm). A conductive spacer layer S made of Cu, a pinned layer (fixed layer, fixed magnetic layer) P, and a capping layer C made of titanium (Ti) or tantalum (Ta) having a film thickness of 2.5 nm (25 mm). Yes. The free layer F includes a CoZrNb amorphous magnetic layer 12a-21 having a film thickness of 8 nm (80 mm) formed immediately above the substrate 11, a NiFe magnetic layer 12a-22 having a film thickness of 3.3 nm (33 mm), The CoFe layer 12a-23 has a thickness of about 1 to 3 nm (10 to 30 mm). The CoZrNb amorphous magnetic layer 12a-21 and the NiFe magnetic layer 12a-22 constitute a soft ferromagnetic thin film layer. On the other hand, the pinned layer P is formed by superposing a CoFe magnetic layer 12a-25 having a thickness of 2.2 nm (22 Å) and an antiferromagnetic film 12a-26 having a thickness of 24 nm (240 Å).

  Subsequently, a permanent magnet array was brought close to the obtained laminated body, and regularized heat treatment (pinning treatment) was performed to fix the magnetization direction of the pinned layer P. In this case, the regularization heat treatment (pinning treatment) is performed so that the polarities of the upper ends (lower ends) of the adjacent permanent bar magnet pieces 31, 32, 33, and 34 are different from each other, as schematically shown in FIG. A permanent bar magnet array (magnet array) 30 arranged in parallel with each other is prepared. The permanent bar magnet array 30 was placed on the substrate 11 so as to be at an angle of 45 ° with respect to the plane of the substrate 11 and heated to a predetermined temperature. Specifically, in the state shown in FIG. 15B, the substrate 11 and the permanent bar magnet array (magnet array) 30 are fixed, and these are heated to 260 ° C. to 290 ° C. in a vacuum, and in this state 4 A regularized heat treatment (pinning treatment) was performed by allowing to stand for about an hour. In FIG. 15B, the state of the magnetic poles on the lower surface of the permanent bar magnet array 30 is shown.

  Here, as shown in FIG. 15B, the first X-axis GMR element 12a is located on the left side of the center line L3 in the width direction of the permanent bar magnet piece 33, and the second X-axis GMR element 12b is a permanent bar magnet. Since they are located on the right side of the center line L2 in the width direction of the piece 32, they are magnetized in the direction of the magnetic field from the permanent bar magnet piece 32 toward the permanent bar magnet piece 33. As a result, in the first X-axis GMR element 12a and the second X-axis GMR element 12b, the magnetization direction of the pinned layer is fixed in the directions of solid arrows a1 and b1 in FIG. Similarly, the third X-axis GMR element 12 c is positioned on the left side of the center line L 2 in the width direction of the permanent bar magnet piece 32, and the fourth X-axis GMR element 12 d is from the center line L 1 in the width direction of the permanent bar magnet piece 31. Are also magnetized in the direction of the magnetic field from the permanent bar magnet piece 32 toward the permanent bar magnet piece 31. As a result, in the third X-axis GMR element 12c and the fourth X-axis GMR element 12d, the magnetization direction of the pinned layer is fixed in the directions of solid arrows c1 and d1 in FIG.

  Further, the first Y-axis GMR element 12e is positioned on the left side of the center line L3 in the width direction of the permanent bar magnet piece 33, and the second Y-axis GMR element 12f is in the center line L2 in the width direction of the permanent bar magnet piece 32. Since they are located on the right side, they are magnetized in the direction of the magnetic field from the permanent bar magnet piece 32 toward the permanent bar magnet piece 33. As a result, in the first Y-axis GMR element 12e and the second Y-axis GMR element 12f, the magnetization directions of the pinned layers are fixed in the directions of solid arrows e1 and f1 in FIG. Similarly, the third Y-axis GMR element 12g is positioned on the left side of the center line L2 in the width direction of the permanent bar magnet piece 32, and the fourth Y-axis GMR element 12h is from the center line L1 in the width direction of the permanent bar magnet piece 31. Since these are also located on the right side, they are magnetized in the direction of the magnetic field from the permanent bar magnet piece 32 toward the permanent bar magnet piece 33. As a result, in the third Y-axis GMR element 12g and the fourth Y-axis GMR element 12h, the magnetization direction of the pinned layer is fixed in the directions of solid arrows g1 and h1 in FIG.

  Further, since the first Z-axis GMR element 12i and the second Z-axis GMR element 12j are located on the left side of the center line L3 in the width direction of the permanent bar magnet piece 33, they are changed from the permanent bar magnet piece 32 to the permanent bar magnet piece 33. It becomes magnetized in the direction of the magnetic field. As a result, the first Z-axis GMR element 12i and the second Z-axis GMR element 12j are moved from the X axis in the positive direction of the Z axis within the slope of the protrusion (bank portion) 15 in the direction of solid arrows i1 and j1 in FIG. The magnetization direction of the pinned layer is fixed in the direction inclined by 45 °. Similarly, since the third Z-axis GMR element 12k and the fourth Z-axis GMR element 12l are located on the right side of the center line L2 in the width direction of the permanent bar magnet piece 32, they are changed from the permanent bar magnet piece 32 to the permanent bar magnet piece 33. It is magnetized in the direction of the magnetic field toward. As a result, the third Z-axis GMR element 12k and the fourth Z-axis GMR element 12l move from the X axis in the negative direction of the Z axis within the slope of the protrusion (bank portion) 15 in the direction of the solid arrows k1 and 11 in FIG. The magnetization direction of the pinned layer is fixed in the direction inclined by 45 °.

  Thereafter, a resist is applied on the surface of the GMR multilayer film 11n so as to have an arbitrary thickness, for example, 2 μm in a flat portion, a mask is disposed on the resist surface, and baking and development are performed. Unnecessary resist is removed, and a resist film having the same pattern as the GMR multilayer film 11n obtained later is formed. At that time, the resist is tapered in order to appropriately perform etching at the projecting portion (bank portion) 15 and to adjust the cross-sectional shape of the projecting portion (bank portion) 15. Thereafter, the portion of the GMR multilayer film 11n not protected by the resist film is removed by ion milling to form the GMR multilayer film 11n in a predetermined shape (for example, a plurality of narrow strips). At that time, both the GMR multilayer film 11n and the bias magnet film 11m remain in the via portion. This is to prevent disconnection at the edge of the via portion.

Next, the resist film is removed, and a nitride film 11o made of, for example, a Si ₃ N ₄ film having a thickness of 10,000 mm is formed thereon by plasma CVD, and then a polyimide film 11p is formed thereon. A protective film was formed. Next, using the polyimide film 11p on the pad portion as a mask, the nitride film 11o on the pad portion is removed by etching to open the pad portion, and each pad is formed, and a wiring for connecting these is formed. The substrate 11 is cut. As described above, the triaxial magnetic sensor 10 of the first embodiment shown in FIG. 1 is manufactured.

2. Example 2
Then, the three-axis magnetic sensor of the second embodiment will be described with reference to FIGS. 16 to 19. 16 is a schematic configuration diagram schematically showing a triaxial magnetic sensor of Example 2, FIG. 16 (a) is a plan view, and FIG. 16 (b) is an E diagram in FIG. 16 (a). It is sectional drawing which shows -E 'cross section. FIG. 17 is a diagram schematically showing the pinning direction and sensitivity direction of the triaxial magnetic sensor of FIG. 16, and FIG. 17 (a) is a plan view schematically showing the entire plane. FIG. 17B is a perspective view schematically showing an enlarged F part in FIG. 17A, and FIG. 17C is a perspective view schematically showing an enlarged G part in FIG. It is.

  18 is a block diagram showing the bridge connection, FIG. 18 (a) is a block diagram showing the bridge connection of the X-axis sensor, and FIG. 18 (b) is a block diagram showing the bridge connection of the Y-axis sensor. FIG. 18C is a block diagram showing the bridge connection of the Z-axis sensor. FIG. 19 is a diagram showing a regularized heat treatment (pinning process), FIG. 19A is a perspective view schematically showing a bar magnet array used for the regularized heat treatment (pinning process), and FIG. It is a top view which shows typically the state of regularization heat processing (pinning process).

  As shown in FIG. 16, the triaxial magnetic sensor 20 of the second embodiment has a square shape having sides along the X axis and the Y axis that are orthogonal to each other in plan view (that is, the substrate 11 of the first embodiment described above). And a substrate 21 made of a quartz substrate or a silicon substrate having a small thickness in the Z-axis direction perpendicular to the X-axis and the Y-axis. In addition, by using such a square substrate 21, it is possible to achieve further downsizing than the triaxial magnetic sensor of the first embodiment.

A total of 12 X-axis GMR elements 22a to 22d and Y-axis GMR elements 22e to 22h formed on the substrate 21 and four Z-axis GMR elements 22i to 22l are formed. GMR element, pad portion (portion for extracting output from wiring: not shown) and via portion (point connecting to wiring from GMR element, this via portion is not finally exposed: not shown) ) As well as wiring (not shown). An LSI and a wiring layer are formed in the substrate 21 in the same manner as the substrate 11 of the first embodiment described above. A digital output magnetic sensor is used in a substrate using the substrate in which the LSI is formed. In the case of using a substrate on which only a wiring layer is formed, an analog output magnetic sensor is formed.

  Here, the X-axis GMR element includes a first X-axis GMR element 22a, a second X-axis GMR element 22b, a third X-axis GMR element 22c, and a fourth X-axis GMR element 22d. In the vicinity of the right end portion of the X axis, the first X axis GMR element 22a is disposed above the Y axis center, and the second X axis GMR element 22b is disposed below the first X axis GMR element 22b. Further, in the vicinity of the left end portion of the X axis, the third X axis GMR element 22c is disposed above the Y axis center, and the fourth X axis GMR element 22d is disposed below the third X axis GMR element 22d.

  The Y-axis GMR element includes a first Y-axis GMR element 22e, a second Y-axis GMR element 22f, a third Y-axis GMR element 22g, and a fourth Y-axis GMR element 22h. The first Y-axis GMR element 22e is arranged on the right side of the X-axis center near the upper end of the Y-axis, and the second Y-axis GMR element 22f is arranged on the left side. In addition, a third Y-axis GMR element 22g is disposed on the right side of the X-axis center near the lower end of the Y-axis, and a fourth Y-axis GMR element 22h is disposed on the left.

  Further, the Z-axis GMR element includes a first Z-axis GMR element 22i, a second Z-axis GMR element 22j, a third Z-axis GMR element 22k, and a fourth Z-axis GMR element 22l. The first Z-axis GMR element 22i is disposed on the left of the upper right corner of the substrate 22, and the second Z-axis GMR element 22j is disposed on the lower right side thereof. A third Z-axis GMR element 22k is disposed below the first Y-axis GMR element 22e at the lower left corner of the upper right corner of the substrate 22, and a fourth Z-axis GMR element 22l is disposed at the lower right side thereof.

Each of the GMR elements 22a to 22d, 22e to 22h, and 22i to 22l is an even number arranged in parallel and adjacent to each other in a strip shape (in this case, for example, the number is preferably four, but it is desirable that the even number is one or more. Any number of GMR bars may be provided, and these GMR bars are connected in series by a magnet film (bias magnet film), and a magnet film serving as a terminal portion is connected to these end portions. ing.
In this case, each GMR bar of the X-axis GMR elements 22a to 22d is formed on a plane parallel to the surface of the substrate 21, and is arranged so that its longitudinal direction is parallel to the Y-axis (perpendicular to the X-axis). Has been. Each GMR bar of the Y-axis GMR elements 22e to 22h is formed on a plane parallel to the surface of the substrate 21, and is arranged so that its longitudinal direction is parallel to the X-axis (perpendicular to the Y-axis). The X-axis GMR elements 22a to 22d are arranged so as to be orthogonal to the longitudinal direction of each GMR bar.

  Further, each GMR bar of the Z-axis GMR elements 22i to 22l has one inclined surface (inclination angle) on each inclined surface of a plurality of protrusions (bank portions) 25 having a trapezoidal cross-sectional shape formed on the substrate 21. Is formed at approximately 45 °) and one GMR bar (for example, 22i-1, 22i-2, 22i-3, 22i-4 (22j-1, 22j-2, 22j-3, 22j-4) are formed so that the longitudinal direction thereof is 45 ° with respect to the X axis (Y axis).

  In this case, in the X-axis GMR elements 22a and 22b, the bias magnet film is in a direction that forms an acute angle with the longitudinal direction of each GMR bar (direction perpendicular to the X-axis) and the direction of magnetization (magnetization vector) of the pinned layer. Is given a bias magnetic field. Then, a pinned layer is formed so that the direction of magnetization (magnetization vector) is pinned (fixed) in a direction of 45 ° with respect to the positive direction of the X axis (directions of solid arrows a1 and b1 in FIG. 17A). ing.

  Accordingly, the sensitivity direction of the X-axis GMR elements 22a and 22b is a direction perpendicular to the longitudinal direction of each GMR bar, that is, the X-axis positive direction (the directions of dotted arrows a2 and b2 in FIG. 17A). Thereby, when a magnetic field is applied in the directions of the dotted arrows a2 and b2 in FIG. 17A, the resistance values of the first X-axis GMR element 22a and the second X-axis GMR element 22b decrease in proportion to the magnitude of the magnetic field. When the magnetic field is applied in the direction opposite to the directions of the dotted arrows a2 and b2 in FIG. 17A, the resistance values of the first X-axis GMR element 22a and the second X-axis GMR element 22b are proportional to the magnitude of the magnetic field. Will increase.

  On the other hand, in the third X-axis GMR element 22c and the fourth X-axis GMR element 22d, the bias magnet film has a direction parallel to the longitudinal direction of each GMR bar (direction perpendicular to the X axis) and the magnetization (magnetization) of the pinned layer. A bias magnetic field is applied in a direction that makes an acute angle with the direction of the vector (a direction opposite to the bias magnetic field of the first X-axis GMR element 22a and the second X-axis GMR element 22b by 180 °). Then, the direction of magnetization (magnetization vector) is in the direction of −45 ° with respect to the negative X axis (in the directions of solid arrows c1 and d1 in FIG. 17A), the first X axis GMR element 22a and the second X axis GMR element 22b. The pinned layer is formed so as to be pinned (fixed) in the direction opposite to the direction of magnetization of 180 °.

  Therefore, the sensitivity directions of the third X-axis GMR element 22c and the fourth X-axis GMR element 22d are perpendicular to the longitudinal direction of each GMR bar, that is, the X-axis negative direction (dotted arrow c2, in FIG. 17A). In the d2 direction, the sensitivity direction of the first X-axis GMR element 22a and the second X-axis GMR element 22b is 180 ° opposite. As a result, when a magnetic field is applied in the directions of the dotted arrows c2 and d2 in FIG. 17A, the resistance values of the third X-axis GMR element 22c and the fourth X-axis GMR element 22d decrease in proportion to the magnitude of the magnetic field. When a magnetic field is applied in the direction opposite to the dotted arrows c2 and d2 in FIG. 17A, the resistance values of the third X-axis GMR element 22c and the fourth X-axis GMR element 22d are proportional to the magnitude of the magnetic field. Will increase.

  Further, in the first Y-axis GMR element 22e and the second Y-axis GMR element 22f, the bias magnet film is in the longitudinal direction of each GMR bar and in an acute angle with the direction of magnetization (magnetization vector) of the pinned layer (that is, the first The bias magnetic field is applied in the direction opposite to the direction in which the bias magnetic fields of the 1X-axis GMR element 22a and the second X-axis GMR element 22b are rotated 90 ° counterclockwise. Then, the pinned layer is formed so that the direction of magnetization (magnetization vector) is pinned (fixed) in the direction of 45 ° with respect to the positive direction of the Y-axis (the direction of solid arrows e1 and f1 in FIG. 17A). ing.

  Therefore, the sensitivity directions of the first Y-axis GMR element 22e and the second Y-axis GMR element 22f are the directions perpendicular to the longitudinal direction of each GMR bar, that is, the Y-axis positive direction (the direction of the dotted arrows e2, f2 in FIG. 17A). )become. Thereby, when a magnetic field is applied in the directions of the dotted arrows e2 and f2 in FIG. 17A, the resistance values of the first Y-axis GMR element 22e and the second Y-axis GMR element 22f decrease in proportion to the magnitude of the magnetic field. When a magnetic field is applied in the direction opposite to the dotted arrows e2 and f2 in FIG. 17A, the resistance values of the first Y-axis GMR element 22e and the second Y-axis GMR element 22f are proportional to the magnitude of the magnetic field. Will increase.

  On the other hand, in the third Y-axis GMR element 22g and the fourth Y-axis GMR element 22h, the bias magnet film has the longitudinal direction of each GMR bar (direction perpendicular to the Y axis) and the magnetization (magnetization vector) direction of the pinned layer. A bias magnetic field is applied in a direction that forms an acute angle with the first Y-axis GMR element 22e and the second Y-axis GMR element 22f. Then, the pinned layer is formed so that the direction of magnetization (magnetization vector) is pinned (fixed) in the direction of −135 ° with respect to the negative Y-axis direction (the directions of solid arrows g1 and h1 in FIG. 17A). Has been.

  Therefore, the sensitivity direction of the third Y-axis GMR element 22g and the fourth Y-axis GMR element 22h is the direction perpendicular to the longitudinal direction of each GMR bar, that is, the Y-axis negative direction (dotted arrow g2, in FIG. 17A). In the h2 direction, the sensitivity direction of the first Y-axis GMR element 22e and the second Y-axis GMR element 22f is 180 ° opposite. Thereby, when a magnetic field is applied in the directions of the dotted arrows g2 and h2 in FIG. 17A, the resistance values of the third Y-axis GMR element 22g and the fourth Y-axis GMR element 22h decrease in proportion to the magnitude of the magnetic field. When a magnetic field is applied in the direction opposite to the dotted arrows g2 and h2 in FIG. 17A, the resistance values of the third Y-axis GMR element 22g and the fourth Y-axis GMR element 22h are proportional to the magnitude of the magnetic field. Will increase.

  Further, in the first Z-axis GMR element 22i and the second Z-axis GMR element 22j, as schematically shown in FIG. 17B, the bias magnet films 22i-5, 22i-6, 22i-7 (22j-5, 22j-6, 22j-7) is the longitudinal direction (X of each GMR bar 22i-1, 22i-2, 22i-3, 22i-4 (22j-1, 22j-2, 22j-3, 22j-4). Direction of 45 ° with respect to the axis and the Y-axis) and a direction that forms an acute angle with the direction of magnetization (magnetization vector) of the pinned layer, that is, each slope (inclination angle is approximately 45 °) of the protrusion (bank portion) 15. On the plane, a bias magnetic field is applied in a direction that makes an acute angle with the direction of magnetization (magnetization vector) of the pinned layer with respect to the X-axis and Y-axis that are the longitudinal directions. And the direction of magnetization (magnetization vector) is pinned (fixed) in a direction (solid arrow i1, j1 direction in FIG. 17B) inclined by 45 ° in the positive direction of the Z axis within each inclined surface of the protrusion (bank portion) 25. The pinned layer is formed as shown in FIG.

  The GMR bars 22i-1, 22i-2, 22i-3, 22i-4 (22j-1, 22j-2, 22j-3, 22j-4) are bias magnet films 22i-5, 22i-6. , 22i-7 (22j-5, 22j-6, 22j-7). As a result, the x-axis component and the y-axis component are cancelled. Therefore, the sensitivity directions of the first Z-axis GMR element 22i and the second Z-axis GMR element 22j are perpendicular to the longitudinal direction of each GMR bar. The magnetic field was applied in the positive direction of the Z-axis, that is, in the direction of dotted arrows i2 and j2 in FIG. 17B (the direction from the back of the paper to the front) and in the direction of dotted arrows i2 and j2 in FIG. In this case, the resistance values of the first Z-axis GMR element 22i and the second Z-axis GMR element 22j decrease in proportion to the magnitude of the magnetic field, and a magnetic field is applied in the direction opposite to the dotted arrows i2 and j2 in FIG. In this case, the resistance values of the first Z-axis GMR element 22i and the second Z-axis GMR element 22j increase in proportion to the magnitude of the magnetic field.

  On the other hand, in the third Z-axis GMR element 22k and the fourth Z-axis GMR element 22l, as schematically shown in FIG. 17C, the bias magnet films 22k-6, 22k-7, 22k-8 (221-6, 22l-6) 22l-7, 22l-8) is the longitudinal direction (X of each GMR bar 22k-1, 22k-2, 22k-3, 22k-4 (22l-1, 22l-2, 22l-3, 22l-4). Direction of 45 ° with respect to the axis and the Y-axis) and a direction that forms an acute angle with the direction of magnetization (magnetization vector) of the pinned layer, that is, each slope (inclination angle is approximately 45 °) of the protrusion (bank portion) 15. On the plane, a bias magnetic field is applied in a direction that makes an acute angle with the direction of magnetization (magnetization vector) of the pinned layer with respect to the X-axis and Y-axis that are the longitudinal directions. Then, the direction of magnetization (magnetization vector) is pinned in the direction of 45 ° with respect to the negative Z-axis direction (the directions of solid arrows k1 and l1 in FIG. A pinned layer is formed so as to be fixed.

  These GMR bars 22k-1, 22k-2, 22k-3, 22k-4 (221-l, 22l-2, 22l-3, 22l-4) are bias magnet films 22k-6, 22k-7. , 22k-8 (221- 6, 22l-7, 22l-8). As a result, the x-axis component and the y-axis component are canceled, and therefore the sensitivity directions of the third Z-axis GMR element 22k and the fourth Z-axis GMR element 22l are perpendicular to the longitudinal direction of each GMR bar. The magnetic field is applied in the negative direction of the Z-axis, that is, in the k2 and l2 directions of the dotted arrows in FIG. 17C (the direction from the front to the back of the page), and in the directions of the dotted arrows k2 and l2 in FIG. In this case, the resistance values of the third Z-axis GMR element 22k and the fourth Z-axis GMR element 22l decrease in proportion to the magnitude of the magnetic field, and a magnetic field is applied in the direction opposite to the dotted arrows k2 and l2 in FIG. In this case, the resistance values of the third Z-axis GMR element 22k and the fourth Z-axis GMR element 22l increase in proportion to the magnitude of the magnetic field.

  In the X-axis magnetic sensor, FIG. 18 (a) (in FIGS. 18 (a) to 18 (c)), each arrow indicates the direction of magnetization when the pinned layer of each GMR element is pinned. The first to fourth X-axis GMR elements 22a to 22d are connected by full bridge connection as shown in the equivalent circuit in FIG. In such a configuration, the pad 23a and the pad 23b are connected to the positive electrode and the negative electrode of the constant voltage source 24, and are given a potential Vxin + (3 V in this example) and a potential Vxin− (0 (V) in this example). The potentials of the pad 23c and the pad 23d are taken out as the potential Vxout + and the potential Vxout-, respectively, and the potential difference (Vxout + −Vxout−) is taken out as the sensor output Vxout.

  As shown in an equivalent circuit in FIG. 18B, the Y-axis magnetic sensor is configured by first to fourth Y-axis GMR elements 22e to 22h being full-bridge connected. The pad 23e and the pad 23f are connected to the positive electrode and the negative electrode of the constant voltage source 24, and are supplied with a potential Vyin + (3 V in this example) and a potential Vyin- (0 (V) in this example), and the pad 23g and the pad 23h. Is taken out as a sensor output Vyout.

  As shown in the equivalent circuit of FIG. 18C, the Z-axis magnetic sensor includes a first Z-axis GMR element 22i, a second Z-axis GMR element 22j, a first nonmagnetic resistor 22k, and a second nonmagnetic resistor 22l. It is configured by full bridge connection. The pad 23i and the pad 23j are connected to the positive electrode and the negative electrode of the constant voltage source 24, and are supplied with a potential Vyin + (3V in this example) and a potential Vyin− (0 (V) in this example). Is taken out as a sensor output Vyout.

  In addition, since the manufacturing method of the triaxial magnetic sensor 20 of the second embodiment is almost the same as the manufacturing method of the triaxial magnetic sensor 10 of the first embodiment, description of the manufacturing method is omitted. However, the regularizing heat treatment (pinning treatment) will be briefly described below.

  In the regularized heat treatment (pinning process) when manufacturing the triaxial magnetic sensor 20 of the second embodiment, as shown schematically in FIG. 19A, the adjacent permanent bar magnet pieces 31, 32, 33, A permanent bar magnet array 30 (magnet array) 30 arranged in parallel so that the polarities of the upper end (lower end) of 34 are different from each other is prepared. Then, this permanent bar magnet array 30 was arranged on the upper portion of the substrate 21 so as to be at an angle of 45 ° with respect to the plane of the substrate 21, and heated to a predetermined temperature. Specifically, in the state shown in FIG. 19B, the substrate 21 and the permanent bar magnet array (magnet array) 30 are fixed, and these are heated to 260 ° C. to 290 ° C. in a vacuum, and in this state 4 A regularized heat treatment (pinning treatment) was performed by allowing to stand for about an hour. In FIG. 19B, the state of the magnetic poles on the lower surface of the permanent bar magnet array 30 is shown.

  Here, as shown in FIG. 19B, the first X-axis GMR element 22a is located on the left side of the center line L3 in the width direction of the permanent bar magnet piece 33, and the second X-axis GMR element 22b is a permanent bar magnet. Since they are located on the right side of the center line L2 in the width direction of the piece 32, they are magnetized in the direction of the magnetic field from the permanent bar magnet piece 32 toward the permanent bar magnet piece 33. As a result, in the first X-axis GMR element 22a and the second X-axis GMR element 22b, the magnetization direction of the pinned layer is fixed in the directions of solid arrows a1 and b1 in FIG. Similarly, the third X-axis GMR element 22c is positioned on the left side of the center line L2 in the width direction of the permanent bar magnet piece 32, and the fourth X-axis GMR element 22d is from the center line L1 in the width direction of the permanent bar magnet piece 31. Are also magnetized in the direction of the magnetic field from the permanent bar magnet piece 32 toward the permanent bar magnet piece 31. As a result, in the third X-axis GMR element 22c and the fourth X-axis GMR element 22d, the magnetization direction of the pinned layer is fixed in the directions of solid arrows c1 and d1 in FIG.

  The first Y-axis GMR element 22e is located on the left side of the center line L3 in the width direction of the permanent bar magnet piece 33, and the second Y-axis GMR element 22f is located in the width direction of the center line L2 of the permanent bar magnet piece 32. Since they are located on the right side, they are magnetized in the direction of the magnetic field from the permanent bar magnet piece 32 toward the permanent bar magnet piece 33. As a result, in the first Y-axis GMR element 22e and the second Y-axis GMR element 22f, the magnetization direction of the pinned layer is fixed in the directions of solid arrows e1 and f1 in FIG. Similarly, the third Y-axis GMR element 22g is positioned on the left side of the center line L2 in the width direction of the permanent bar magnet piece 32, and the fourth Y-axis GMR element 22h is from the center line L1 in the width direction of the permanent bar magnet piece 31. Since these are also located on the right side, they are magnetized in the direction of the magnetic field from the permanent bar magnet piece 32 toward the permanent bar magnet piece 33. As a result, in the third Y-axis GMR element 22g and the fourth Y-axis GMR element 22h, the magnetization direction of the pinned layer is fixed in the directions of solid arrows g1 and h1 in FIG.

  Further, since the first Z-axis GMR element 22 i and the second Z-axis GMR element 22 j are located on the left side of the center line L 3 in the width direction of the permanent bar magnet piece 33, they are changed from the permanent bar magnet piece 32 to the permanent bar magnet piece 33. It becomes magnetized in the direction of the magnetic field. As a result, the first Z-axis GMR element 22i and the second Z-axis GMR element 22j are moved from the X axis in the positive direction of the Z axis within the slope of the protrusion (bank portion) 25 in the direction of solid arrows i1 and j1 in FIG. The magnetization direction of the pinned layer is fixed in the direction inclined by 45 °. Similarly, since the third Z-axis GMR element 22k and the fourth Z-axis GMR element 22l are located on the right side of the center line L2 in the width direction of the permanent bar magnet piece 32, they are changed from the permanent bar magnet piece 32 to the permanent bar magnet piece 33. It is magnetized in the direction of the magnetic field toward. As a result, the third Z-axis GMR element 22k and the fourth Z-axis GMR element 22l are moved from the X axis in the negative direction of the Z axis within the slope of the protrusion (bank portion) 25 in the direction of the solid arrows k1 and 11 in FIG. The magnetization direction of the pinned layer is fixed in the direction inclined by 45 °.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram which shows typically the triaxial magnetic sensor of Example 1, Fig.1 (a) is a top view, FIG.1 (b) is sectional drawing which shows the AA cross section of Fig.1 (a). . FIG. 2 is a diagram schematically showing a schematic configuration of a giant magnetoresistive effect element used in the three-axis magnetic sensor of the present invention. FIG. 2A is a diagram in which a plurality of giant magnetoresistive effect element (GMR) bars are connected to each other. FIG. 2B is a plan view showing a state in which a giant magnetoresistive element is configured, and FIG. 2B is a cross-sectional view schematically showing a BB ′ cross section of FIG. These are figures which show typically the lamination state inside FIG.2 (b). FIG. 3 is a diagram schematically illustrating a pinning direction and a sensitivity direction of the triaxial magnetic sensor in FIG. 1, FIG. 3A is a plan view schematically illustrating the entire plane, and FIG. FIG. 3C is a perspective view schematically showing an enlarged C part of FIG. 3A, and FIG. 3C is a perspective view schematically showing an enlarged D part of FIG. FIG. 4A is a block diagram showing the bridge connection of the X-axis sensor, and FIG. 4B is the block diagram showing the bridge connection of the Y-axis sensor. FIG. 4C is a block diagram illustrating the bridge connection of the Z-axis sensor. It is sectional drawing which shows typically the triaxial magnetic sensor of Example 1 in the middle of manufacture. It is sectional drawing which shows typically the triaxial magnetic sensor of Example 1 in the middle of manufacture. It is sectional drawing which shows typically the triaxial magnetic sensor of Example 1 in the middle of manufacture. It is sectional drawing which shows typically the triaxial magnetic sensor of Example 1 in the middle of manufacture. It is sectional drawing which shows typically the triaxial magnetic sensor of Example 1 in the middle of manufacture. It is sectional drawing which shows typically the triaxial magnetic sensor of Example 1 in the middle of manufacture. It is sectional drawing which shows typically the triaxial magnetic sensor of Example 1 in the middle of manufacture. It is sectional drawing which shows typically the triaxial magnetic sensor of Example 1 in the middle of manufacture. It is sectional drawing which shows typically the triaxial magnetic sensor of Example 1 in the middle of manufacture. It is sectional drawing which shows typically the triaxial magnetic sensor of Example 1 in the middle of manufacture. FIG. 15 is a diagram illustrating a regularized heat treatment (pinning process) of the triaxial magnetic sensor of Example 1, and FIG. 15A is a perspective view schematically illustrating a bar magnet array used for the regularized heat treatment (pinning process); FIG. 15B is a plan view schematically showing a state of ordered heat treatment (pinning treatment). FIG. 16A is a schematic configuration diagram illustrating a three-axis magnetic sensor of Example 2, FIG. 16A is a plan view, and FIG. 16B is a cross-sectional view illustrating a cross section taken along line E-E ′ of FIG. It is a figure which shows typically the pinning direction and sensitivity direction of the triaxial magnetic sensor of FIG. 16, Fig.17 (a) is a top view which shows typically the whole plane, FIG.17 (b) is FIG. It is a perspective view which expands and shows typically the F section of (a), and FIG.17 (c) is a perspective view which expands and schematically shows the G section of Fig.17 (a). FIG. 18A is a block diagram illustrating a bridge connection of an X-axis sensor, and FIG. 18B is a block diagram illustrating a bridge connection of a Y-axis sensor. FIG. 18C is a block diagram showing the bridge connection of the Z-axis sensor. FIG. 19 is a diagram showing a regularized heat treatment (pinning process) of the triaxial magnetic sensor of Example 2, and FIG. 19A is a perspective view schematically showing a bar magnet array used for the regularized heat treatment (pinning process); FIG. 19B is a plan view schematically showing the state of the regularized heat treatment (pinning treatment). It is a schematic block diagram which shows typically the magnetic sensor of a prior art example, Fig.20 (a) is a top view, FIG.20 (b) is the side view. It is a figure which shows the bridge connection of the magnetic sensor of a prior art example.

Explanation of symbols

10 ... three-axis magnetic sensor of Example 1, 11 ... substrate, 11a ... wiring layer, 11b ... interlayer insulation film, 11c, 11d ... opening, 11e ... SiO ₂ film, 11f ... Si ₃ N ₄ film, 11g, 11h ... opening, 11i ... SiO ₂ film, 11j ... resist film, 11k ... opening, 11m ... bias magnet film, 11n ... GMR multilayer film, 11o ... Si ₃ N ₄ film, 11p ... polyimide film, 15 ... projection (Tsutsumi Part), 12a ... 1st X-axis GMR element, 12a-1 to 12a-4 ... GMR bar, 12a-5 to 12a-9 ... bias magnet film, 12b ... 2nd X-axis GMR element, 12c ... 3rd X-axis GMR element, 12d ... 4th X-axis GMR element, 13a-13d ... Pad, 14 ... Constant voltage source, 12e ... 1st Y-axis GMR element, 12f ... 2nd Y-axis GMR element, 12g ... 3rd Y-axis GMR element, 12h ... 4th Y-axis GMR Child, 13e to 13h ... pad, 12i ... first Z-axis GMR element, 12j ... second Z-axis GMR element, 12k ... third Z-axis GMR element, 12l ... fourth Z-axis GMR element, 13i-13l ... pad, 20 ... Examples 2 triaxial magnetic sensors, 21 ... substrate, 22a to 22d ... first to fourth X axis GMR elements, 22e to 22h ... first to fourth Y axis GMR elements, 22i to 22j ... first to second Z axis GMR elements, 22k-22l ... 1st-2nd nonmagnetic resistor, 23a-23d ... Pad, 24 ... Constant voltage source, 23e-23h ... Pad, 23i-23l ... Pad, 25 ... Projection (bank part)

Claims (7)

An X-axis sensor in which a plurality of giant magnetoresistive elements are bridged, a Y-axis sensor in which a plurality of giant magnetoresistive elements are bridged, and a Z-axis sensor in which a plurality of giant magnetoresistive elements are bridged Is a three-axis magnetic sensor provided in one substrate,
The giant magnetoresistive element is formed of at least one giant magnetoresistive element bar;
The giant magnetoresistive element of the X-axis sensor is formed on a plane parallel to the plane of the substrate, the longitudinal direction of the giant magnetoresistive element bar is the Y-axis direction, and the giant magnetoresistive element The magnetization direction of the pinned layer of the effect element bar is a direction at a predetermined angle with respect to the X axis, and the sensitivity direction is a direction perpendicular to the longitudinal direction of the giant magnetoresistive effect element bar.
The giant magnetoresistive element of the Y-axis sensor is formed on a plane parallel to the plane of the substrate, the longitudinal direction of the giant magnetoresistive element bar is the X-axis direction, and the giant magnetoresistive element The magnetization direction of the pinned layer of the effect element bar is a direction at a predetermined angle with respect to the Y axis, and the sensitivity direction is a direction perpendicular to the longitudinal direction of each giant magnetoresistive element bar,
The giant magnetoresistive element of the Z-axis sensor is formed on a slope provided on the substrate, and the direction of magnetization is formed within the slope, and the direction of sensitivity is the giant magnetoresistive effect. A slope formed so as to intersect with the longitudinal direction of the element bar and each giant magnetoresistive element bar is opposed to the Z axis perpendicular to the plane of the substrate at the same angle. The giant magnetoresistive effect element formed on each of the inclined surfaces is formed with a longitudinal direction of the giant magnetoresistive effect element bar being 45 ° with respect to the X-axis direction or the Y-axis direction of the substrate. A three-axis magnetic sensor , wherein giant magnetoresistive elements composed of bars are arranged in parallel .   The predetermined angle of the magnetization direction of the pinned layer of the giant magnetoresistive element bar of the X-axis sensor and the predetermined angle of the magnetization direction of the pinned layer of the giant magnetoresistive element bar of the Y-axis sensor are 45 °. The three-axis magnetic sensor according to claim 1.   The three-axis magnetic sensor according to claim 1, wherein the giant magnetoresistive effect element includes a plurality of giant magnetoresistive effect element bars arranged in parallel.   The plurality of giant magnetoresistive effect element bars arranged in parallel are arranged adjacent to each other, and these giant magnetoresistive effect element bars are connected in series by a bias magnet film. Three-axis magnetic sensor. The three-axis magnetic sensor according to any one of claims 1 to 4 , wherein the planar shape of the substrate is a rectangular shape or a square shape with an aspect ratio of 1: 2. One X-axis sensor in which a plurality of magnetoresistive elements are bridge-connected, a Y-axis sensor in which a plurality of magnetoresistive elements are bridge-connected, and a Z-axis sensor in which a plurality of magnetoresistive elements are bridge-connected A method of manufacturing a three-axis magnetic sensor provided in a substrate,
A magnetoresistive effect element forming step for forming a plurality of magnetoresistive effect elements serving as X-axis sensors, a plurality of magnetoresistive effect elements serving as Y-axis sensors, and a plurality of magnetoresistive effect elements serving as Z-axis sensors on the substrate. When,
At the same time ordering the respective bridge-connected set of the two magneto-resistive element is heated while applying a magnetic field of mutually different direction can the magnetoresistive element of each magnetoresistive element formed on said substrate A method of manufacturing a triaxial magnetic sensor, comprising: a regularized heat treatment step for heat treatment. In the ordered heat treatment step, a bar magnet array bar magnet in which a plurality of bar magnets are arranged in parallel so that the polarities of the bar magnets adjacent to each other on the substrate on which the giant magnetoresistive elements are formed are alternately different. 7. The method of manufacturing a triaxial magnetic sensor according to claim 6 , wherein the heat treatment is performed by heating after the substrate is arranged so that the arrangement direction forms an angle of 45 [deg.] With the substrate.

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