JP2012037463A - Magnetic sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic sensor in which, in particular, two kinds of magnetoresistance effect elements with orthogonal sensitivity axes can be formed on the same chip.SOLUTION: A first magnetoresistance effect element 15 and a second magnetoresistance effect element 16 are provided on the same sensor chip, and each of the magnetoresistance effect element has an element part in which a free magnetic layer and a fixed magnetic layer are stacked via a non-magnetic layer, and a hard bias layer for supplying a bias magnetic field to the element part. The fixed magnetic layer of each element part has a self pin stopper structure in which a first magnetic layer and a second magnetic layer are stacked via a non-magnetic intermediate layer, and the first magnetic layer and the second magnetic layer are magnetization-fixed in anti-parallel. A magnetization fixing direction of the first element part of the first magnetoresistance effect element and a magnetization fixing direction of the second element part of the second magnetoresistance effect element are orthogonal. The first hard bias layer and the second hard bias layer have the same magnetization direction, but bias magnetic fields supplied to the element parts are orthogonal.

Description

  The present invention relates to a magnetic sensor for detecting an external magnetic field.

  Patent Document 1 discloses an invention related to a magnetic sensor. For example, in the magnetic sensor shown in Patent Document 1, eight magnetoresistive elements are arranged, of which four magnetoresistive elements are for detecting an external magnetic field in the X direction, and the remaining four magnetic elements. The resistance effect element is for detecting an external magnetic field in the Y direction.

  Usually, two magnetoresistive elements having the same sensitivity axis direction (fixed magnetization direction of the fixed magnetic layer) are paired as a chip. That is, conventionally, there is a problem that the number of chips increases because magnetoresistive elements with different sensitivity axis directions cannot be formed on the same chip.

JP 2006-66821 A

  Accordingly, the present invention is to solve the above-described conventional problems, and in particular, to provide a magnetic sensor capable of forming two types of magnetoresistive effect elements whose sensitivity axes are orthogonal to each other on the same chip. To do.

The magnetic sensor in the present invention is
A first magnetoresistive element and a second magnetoresistive element are provided on the same sensor chip;
The first magnetoresistive element includes a first element portion in which a free magnetic layer and a pinned magnetic layer are stacked via a nonmagnetic layer, and a first magnetic field for supplying a first bias magnetic field to the first element portion. 1 hard bias layer,
The second magnetoresistive element includes a second element portion in which a free magnetic layer and a pinned magnetic layer are stacked via a nonmagnetic layer, and a second bias magnetic field for supplying the second element portion to the second element portion. A second hard bias layer,
In each pinned magnetic layer of the first element portion and the second element portion, a first magnetic layer and a second magnetic layer are laminated via a nonmagnetic intermediate layer, and the first magnetic layer and the second magnetic layer Is a self-pinned structure in which magnetization is fixed in antiparallel, and the magnetization fixed direction of the second magnetic layer that is the sensitivity axis direction is orthogonal between the first element part and the second element part,
The first hard bias layer and the second hard bias layer have the same magnetization direction, and the first bias magnetic field extends from the first hard bias layer to the first element portion in a direction parallel to the magnetization direction. The second bias magnetic field is supplied from the second hard bias layer to the second element portion from a direction orthogonal to the magnetization direction.

  In the present invention, the first magnetic layer and the second magnetic layer are the non-magnetic intermediate layer for the first element portion constituting the first magnetoresistive element and the second element portion constituting the second magnetoresistive element, respectively. And a self-pinned structure. Further, the first hard bias layer constituting the first magnetoresistive effect element and the second hard bias layer constituting the second magnetoresistive effect element remain in the same magnetization direction from the first hard bias layer to the first hard bias layer. The first bias magnetic field supplied to the element part is in a direction parallel to the magnetization direction, and the second bias magnetic field supplied from the second hard bias layer to the second element part is orthogonal to the magnetization direction. The direction was controlled.

  As described above, according to the present invention, it is possible to easily and appropriately form the first magnetoresistive element and the second magnetoresistive element whose sensitivity axes are orthogonal to each other on the same sensor chip. Therefore, the number of chips mounted on the magnetic sensor can be reduced as compared with the conventional case, and detection accuracy and manufacturing efficiency can be improved.

In the present invention, in the first magnetoresistive effect element, the first direction is the sensitivity axis direction, and in the second magnetoresistive effect element, the second direction orthogonal to the first direction is the sensitivity axis direction. And
The second direction is a magnetization direction for each hard bias layer, the first element portion is supplied with the first bias magnetic field from the second direction, and the second element portion has the first direction. It is preferable that the second bias magnetic field is supplied from the direction.

  In the present invention, it is preferable that the surface of the second hard bias layer facing the second element portion is inclined obliquely from the second direction toward the first direction in plan view. It is. Thereby, the second bias magnetic field in the first direction can be effectively supplied to the second element portion from the second hard bias layer magnetized in the second direction.

  In the present invention, it is preferable that a first sensor chip and a second sensor chip are provided, and the first magnetoresistive element and the second magnetoresistive element are formed on each sensor chip. At this time, it is preferable that the second sensor chip has a configuration in which the first sensor chip is rotated 180 degrees.

  In the present invention, the substrate on which the first magnetoresistive effect element and the second magnetoresistive effect element are formed in each of a plurality of regions is cut between the regions, and the first sensor chip and the second sensor A chip is preferably constructed. Thereby, manufacturing efficiency can be improved.

In the present invention, each sensor chip is provided with two each of the first magnetoresistance effect element and the second magnetoresistance effect element,
An external magnetic field with respect to the first direction by the two first magnetoresistive elements provided in the first sensor chip and the two first magnetoresistive elements provided in the second sensor chip. A first bridge circuit capable of detecting
The two second magnetoresistive elements provided on the first sensor chip and the two second magnetoresistive elements provided on the second sensor chip are orthogonal to the first direction. It is preferable that a second bridge circuit capable of detecting an external magnetic field with respect to the second direction is configured. The output from each bridge circuit can be increased, and the detection accuracy can be improved.

  In the present invention, it is possible to easily and appropriately form the first magnetoresistive element and the second magnetoresistive element whose sensitivity axes are orthogonal to each other on the same sensor chip. Therefore, the number of chips mounted on the magnetic sensor can be reduced as compared with the conventional case, and detection accuracy and manufacturing efficiency can be improved.

FIG. 1A is a plan view (schematic diagram) of the magnetic sensor in the present embodiment, and FIG. 1B is a circuit configuration diagram of the magnetic sensor in the present embodiment. It is a top view of the 1st magnetoresistive effect element and the 2nd magnetoresistive effect element in this embodiment. It is the elements on larger scale of the 2nd magnetoresistive effect element. FIG. 4A is a longitudinal sectional view of the magnetic sensor of the present embodiment, which is cut in the height direction (film thickness direction) along the line AA shown in FIG. c) shows a modification thereof. The fragmentary longitudinal cross-sectional view of the element part in this embodiment is shown. The manufacturing process of the sensor chip which comprises the magnetic sensor in this embodiment is shown with a conceptual diagram. FIG. 7 shows an example of the usage pattern of the magnetic sensor in this embodiment. FIG. 7 (a) is a partial longitudinal sectional view, and FIG. 7 (b) shows the first sensor chip and the second sensor chip constituting the magnetic sensor. It is the figure which piled up the top view and the external shape of the magnet. FIG. 8 shows a magnetic sensor according to the second embodiment. FIG. 8A shows a manufacturing process of the sensor chip constituting the magnetic sensor (same as FIG. 6C), and FIG. 8B shows the substrate 80 from the CC line in FIG. 8A. It is a top view of the magnetic sensor of the state which has arrange | positioned the 1st sensor chip 81 and the 2nd sensor chip 82 which were formed by cut | disconnecting on the support substrate (not shown).

  FIG. 1A is a plan view (schematic diagram) of the magnetic sensor in the present embodiment, and FIG. 1B is a circuit configuration diagram of the magnetic sensor in the present embodiment. FIG. 2 is a plan view of the first magnetoresistive element and the second magnetoresistive element in the present embodiment. FIG. 3 is a partially enlarged plan view of the second magnetoresistance effect element. FIG. 4A is a longitudinal sectional view of the magnetic sensor of the present embodiment, which is cut in the height direction (film thickness direction) along the line AA shown in FIG. c) shows a modification thereof. FIG. 5 shows a partial longitudinal sectional view of the element portion in the present embodiment.

  The X-axis direction (first direction) and the Y-axis direction (second direction) shown in each figure indicate two directions orthogonal to each other in the horizontal plane, and the Z-axis direction indicates a direction orthogonal to the horizontal plane. ing.

  FIG. 1A conceptually shows the magnetic sensor 10 in the present embodiment. The specific configuration of each magnetoresistive element will be described with reference to FIG.

  As shown in FIG. 1A, the magnetic sensor 10 includes a support substrate 9 and a first sensor chip 11 and a second sensor chip 12 installed on the support substrate 9.

  As shown in FIG. 1A, two first magnetoresistive elements 15 and two second magnetoresistive elements 16 are formed on the first sensor chip 11.

  As shown in FIG. 1A, the magnetization pinned direction (P1) of the pinned magnetic layer of the first magnetoresistance effect element 15 is the X2 direction. Further, the magnetization fixed direction (P2) of the pinned magnetic layer of the second magnetoresistive element 16 is the Y2 direction.

  As shown in FIG. 1A, the first bias magnetic field B1 supplied to the first magnetoresistance effect element 15 is in the Y1-Y2 direction. The second bias magnetic field B2 supplied to the second magnetoresistive element 16 is in the X1-X2 direction.

  As shown in FIG. 1A, the arrow indicating the direction of the second bias magnetic field B2 is a diagram bent from the Y direction to the X1-X2 direction. This will be described later. Means that the second bias magnetic field B2 supplied to the second element portion is converted by 90 degrees from the magnetization direction (Y direction).

  The second sensor chip 12 shown in FIG. 1A is configured by rotating the first sensor chip 11 shown in FIG. 1A 180 degrees. Therefore, the magnetization fixed direction (P1) of the pinned magnetic layer of the first magnetoresistive effect element 15 in the second sensor chip 12 is the X1 direction, and the pinned magnetic layer of the first magnetoresistive effect element 15 in the first sensor chip 11 is the same. The direction is 180 degrees opposite to the magnetization fixed direction (P1). The magnetization pinned direction (P2) of the pinned magnetic layer of the second magnetoresistive effect element 16 in the second sensor chip 12 is the Y1 direction, and the pinned magnetic layer of the second magnetoresistive effect element 16 in the first sensor chip 11 is. The direction is 180 degrees opposite to the magnetization fixed direction (P2).

  As shown in FIG. 1A, each of the sensor chips 11 and 12 is formed with a plurality of electrode portions 18, and each of the first magnetoresistive effect element 15 and each of the second magnetoresistive effect elements 16 corresponds to each electrode portion. 18 is electrically connected.

  FIG. 1B is a circuit configuration diagram of the magnetic sensor 10 shown in FIG. Here, each of the first magnetoresistive effect element 15 and the second magnetoresistive effect element 15 on the circuit shown in FIG. 2, in order to clarify whether it is the magnetoresistive effect element 16, reference numerals 15 and 16 and reference numerals 15 a to 15 d and 16 a to 16 d are written together in FIG. 1A, and reference numerals 15 and 16 are added in FIG. Without using them, the symbols 15a to 15d and 16a to 16d shown in FIG.

  As shown in FIG. 1B, the first bridge circuit 7 is configured by the four first magnetoresistive elements 15a to 15b. As shown in FIG. 1B, the first magnetoresistive element 15a in which the magnetization fixed direction (P1) of the pinned magnetic layer is the X2 direction, and the first magnetism in which the magnetization fixed direction (P1) of the pinned magnetic layer is the X1 direction. The resistance effect element 15d is connected in series. The first magnetoresistance effect element 15a is connected to the input terminal (Vdd) 20, the first magnetoresistance effect element 15d is connected to the ground terminal (GND) 21, and the first magnetoresistance effect element 15a and the first magnetoresistance effect element The output terminal (VX1) 22 is connected to 15d. Further, as shown in FIG. 1B, the first magnetoresistive element 15c in which the magnetization fixed direction (P1) of the pinned magnetic layer is the X1 direction and the magnetization fixed direction (P1) of the pinned magnetic layer is the X2 direction. 1 magnetoresistive effect element 15b is connected in series. The first magnetoresistive element 15c is connected to the input terminal (Vdd) 20, the first magnetoresistive element 15b is connected to the ground terminal (GND) 21, and the first magnetoresistive element 15c and the first magnetoresistive element The output terminal (VX2) 23 is connected to 15b.

  As shown in FIG. 1B, the second magnetoresistive element 16a in which the pinned magnetic layer has a magnetization pinned direction (P2) in the Y2 direction, and the pinned magnetic layer has a pinned magnetization direction (P2) in the Y1 direction. The magnetoresistive effect element 16d is connected in series. The second magnetoresistive element 16a is connected to the input terminal (Vdd) 20, the second magnetoresistive element 16d is connected to the ground terminal (GND) 21, and the second magnetoresistive element 16a and the second magnetoresistive element The output terminal (VY1) 24 is connected to 16d. Further, as shown in FIG. 1B, the pinned magnetic layer has a magnetization fixed direction (P2) in the Y1 direction, and the pinned magnetic layer has a magnetization fixed direction (P2) in the Y2 direction. 2 magnetoresistive effect element 16b is connected in series. The second magnetoresistive element 16c is connected to the input terminal (Vdd) 20, the second magnetoresistive element 16b is connected to the ground terminal (GND) 21, and the second magnetoresistive element 16c and the second magnetoresistive element The output terminal (VY2) 25 is connected to 16b.

  FIG. 2 shows the planar shape of the first magnetoresistive element 15 and the second magnetoresistive element 16. For example, FIG. 2 shows the first magnetoresistive effect element 15a and the second magnetoresistive effect element 16a shown in FIG.

  As shown in FIG. 2, the first magnetoresistance effect element 15 (15a) is formed in a meander shape. As shown in FIG. 2, Y1-Y2 having a plurality of first element parts 30 formed at intervals in the Y1-Y2 direction and a first hard bias layer 31 provided between the first element parts 30. A plurality of element coupling bodies 32 extending in the direction are provided at intervals in the X1-X2 direction, and end portions of the element coupling bodies 32 are alternately connected via the connection portions 33. Thus, the meander-shaped first magnetoresistive element 15 is formed.

  As shown in FIG. 2, both end portions of the first magnetoresistance effect element 15 are electrically connected to the electrode portion 18.

  As shown in FIG. 2, the first hard bias layer 31 is formed in a rectangular shape, and an end portion 31a in contact with the first element portion 30 in a plan view is formed in parallel to the X1-X2 direction. Then, the first bias magnetic field B1 in the Y1 direction is supplied from the first hard bias layer 31 magnetized in the Y1-Y2 direction (second direction) to each first element unit 30. As described above, in the first magnetoresistive effect element 15, the direction of the first bias magnetic field B1 supplied from the first hard bias layer 31 to each first element unit 30 is parallel to the magnetization direction.

  On the other hand, the second magnetoresistive effect element 16 (16a) is also formed in a meander shape like the first magnetoresistive effect element 15, but the direction is 90 degrees different from that of the first magnetoresistive effect element 15.

  As shown in FIG. 2, Y1-Y2 having a plurality of second element portions 35 formed at intervals in the X1-X2 direction and a second hard bias layer 36 provided between the second element portions 35. A plurality of element coupling bodies 37 extending in the direction are provided at intervals in the Y1-Y2 direction, and the end portions of the element coupling bodies 37 are alternately connected via the connection portions 38. Thereby, the meander-shaped second magnetoresistive element 16 is formed.

  As shown in FIG. 2, both end portions of the second magnetoresistance effect element 16 are electrically connected to the electrode portion 18.

  FIG. 3 is a partially enlarged plan view showing a part of the second magnetoresistance effect element 16 shown in FIG. 2 in an enlarged manner. Here, for easy explanation, reference numerals 36a to 36c are assigned to the three second hard bias layers shown in FIG.

  In each of the second hard bias layers 36a to 36c shown in FIG. 3, the Y1 side end portions 36a1, 36b1, and 36c1 are magnetized to the N pole, and the Y2 side end portions 36a2, 36b2, and 36c2 are magnetized to the S pole. It is the same Y1-Y2 direction (second direction).

  As shown in FIG. 3, the second hard bias layer 36b has a first side surface 40 formed from the Y2 side end portion 36b2 toward the X2 side end portion 36b3, and from the Y2 side end portion 36b2 to the X1 side end portion 36b4. A second side surface 41 is formed toward the surface. The first side surface 40 and the second side surface 41 are inclined from the Y1-Y2 direction (second direction) toward the X1-X2 direction (first direction). That is, the angle θ1 formed between the side surfaces 40 and 41 and the Y1-Y2 direction is not about 0 ° and 90 °, but is about 30 to 60 °, for example. Each side surface 40, 41 is formed in a straight line shape.

  As shown in FIG. 3, the first side surface 40 and the second side surface 41 are both provided at positions facing the respective second element portions 35 in a plan view.

  The second hard bias layer 36a has a side surface (opposing surface) 43 that faces the first side surface 40 formed in the second hard bias layer 36b in the X1-X2 direction. The side surface 43 of the second hard bias layer 36a and the first side surface 40 of the second hard bias layer 36b are provided substantially parallel to each other. Therefore, the side surface 43 of the second hard bias layer 36a corresponds to the second hard bias layer 36b. Inclined in the same direction as the first side surface 40.

  The second hard bias layer 36c has a side surface (opposing surface) 44 that faces the second side surface 41 formed in the second hard bias layer 36b in the X1-X2 direction. The side surface 44 of the second hard bias layer 36c and the second side surface 41 of the second hard bias layer 36b are provided substantially in parallel. Therefore, the side surface 44 of the second hard bias layer 36c is the same as that of the second hard bias layer 36b. The second side surface 41 is inclined in the same direction.

  As shown in FIG. 3, the side surface 43 of the second hard bias layer 36a and the side surface 44 of the second hard bias layer 36c are provided at positions facing the second element portion 35 in plan view.

  As shown in FIG. 3, each of the second hard bias layers 36a to 36c is magnetized from the Y2 side toward the Y1 direction (second direction). That is, the magnetization direction is the same as that of the first hard bias layer 31 shown in FIG.

  However, unlike the first hard bias layer 31, the second hard bias layers 36a to 36c have a second bias parallel to the X1-X2 direction (first direction) between the inclined side surfaces 40, 41, 43, 44. A magnetic field B2 is generated. Thus, the second bias magnetic field B2 is supplied to the second element unit 35 from a direction (X1-X2 direction) orthogonal to the magnetization direction (Y1-Y2 direction).

  The planar configuration of the first magnetoresistive effect element 15a and the second magnetoresistive effect element 16a shown in FIG. 2 is the other first magnetoresistive effect element 15b and second magnetoresistive effect element 16b formed on the first sensor chip 11. The same applies to. If the drawing of FIG. 2 is rotated by 180 degrees, the planar configuration of the first magnetoresistive effect elements 15c and 15d and the second magnetoresistive effect elements 16c and 16d provided in the second sensor chip 12 is the same.

  As shown in the vertical cross-sectional view of FIG. 4A (partial vertical cross-sectional view cut along the line AA shown in FIG. 3), the second element portion 35 constituting the second magnetoresistive effect element 16 includes: An insulating layer 50 is formed on the support substrate 9. In addition, an insulating layer 51 is provided on the second element portion 35, and each second hard bias layer 36 is formed on the planarized surface of the insulating layer 51.

  As described above, in the configuration of FIG. 4A, the insulating layer 51 exists in the height direction (Z1-Z2) between the second element portion 35 and the second hard bias layer 36. As the film thickness increases, the horizontal component of the second bias magnetic field B2 flowing from the second hard bias layer 36 into the second element part 35 becomes weak, so the insulating layer 51 positioned on the second element part 35 is thinly formed. It is preferable to do.

  Alternatively, as shown in FIG. 4B, a part of the second element portion 35 may be removed, and the second hard bias layer 36 may be formed on the removed recess 35a. However, in FIG. 4B and FIG. 4C to be described next, the second hard bias layer 36 straddling between the element coupling bodies 37 is separated, and the current flows between the element coupling bodies 37. It does not flow through the bias layer 36.

  Alternatively, as shown in FIG. 4C, all the second element portions 35 at the position where the second hard bias layer 36 is formed are deleted, and the second hard bias layer 36 is inserted between the separated second element portions 35. It can also be set as the structure to interpose.

  Each structure shown in FIG. 4 is similarly applied to the first element portion 30 and the first hard bias layer 31 of the first magnetoresistance effect element 15 shown in FIG.

  FIG. 5 is a partial longitudinal sectional view of the first element unit 30. As shown in FIG. 5, the first element unit 30 is formed by laminating, for example, a nonmagnetic underlayer 60, a pinned magnetic layer 61, a nonmagnetic layer 62, a free magnetic layer 63, and a protective layer 64 in this order from the bottom. . Each layer constituting the first element unit 30 is formed by sputtering, for example.

  In the embodiment shown in FIG. 5, the pinned magnetic layer 61 is a laminated ferrimagnetic layer made up of a first magnetic layer 61a, a second magnetic layer 61b, and a nonmagnetic intermediate layer 61c interposed between the first magnetic layer 61a and the second magnetic layer 61b. It is a structure. Each of the first magnetic layers 61a and 61b is made of a soft magnetic material such as a CoFe alloy (cobalt-iron alloy). The nonmagnetic intermediate layer 61c is made of Ru or the like. The nonmagnetic layer 62 is formed of a nonmagnetic material such as Cu (copper). The free magnetic layer 63 is made of a soft magnetic material such as a NiFe alloy (nickel-iron alloy). The protective layer 64 is Ta (tantalum) or the like.

  In the present embodiment, the pinned magnetic layer 61 has a laminated ferrimagnetic structure, and the first magnetic layer 61a and the second magnetic layer 61b have a self-pinned structure in which the magnetization is fixed antiparallel. Conventionally, an antiferromagnetic layer is formed in contact with a pinned magnetic layer, an exchange coupling magnetic field Hex is generated between the antiferromagnetic layer and the pinned magnetic layer by heat treatment in a magnetic field, and the pinned magnetic layer is moved in a predetermined direction. Although the magnetization is fixed, in this embodiment, the antiferromagnetic layer is not used, and thus the magnetic layers 61a and 61c constituting the fixed magnetic layer 61 are fixed by magnetization without performing heat treatment in a magnetic field (self-pinning). Construction). The magnetization fixing force of each of the magnetic layers 61a and 61b only needs to be large enough to prevent magnetization fluctuation even when the external magnetic field H is applied.

  In order to increase the magnetization pinning force, the pinned magnetic layer 61 has a laminated ferrimagnetic structure, and an antiparallel coupling magnetic field is generated between the magnetic layers 61a and 61b by the RKKY interaction via the nonmagnetic intermediate layer 61c. A magnetic material having a relatively high coercive force Hc (eg, a CoFe alloy) can be used for the magnetic layers 61a and 61b, or the nonmagnetic underlayer 60 can increase the coercive force Hc of the pinned magnetic layer 61 more effectively. Layer (for example, (NiFeCr or Cu)), or the nonmagnetic underlayer 60 can increase the magnetostriction constant λs of the pinned magnetic layer 61 more effectively (for example, a thin and antiferromagnetic layer). A non-magnetic metal layer such as IrMn or PtMn.

  The laminated structure shown in FIG. 5 is the same in the second element portion 35 constituting the second magnetoresistance effect element 16.

  The hard bias layers 31 and 36 are, for example, CoPt or CoPtCr, but the material is not particularly limited.

  In the present embodiment, the first magnetoresistive element in which the fixed magnetization direction of the fixed magnetic layer 61 (defined by the magnetization direction of the second magnetic layer 61b), which is the sensitivity axis direction, is orthogonal to the same sensor chip 11, 12. 15 and the second magnetoresistive element 16 can be formed.

  For that purpose, several requirements are necessary. First, for example, after the first magnetoresistive effect element 15 is formed before the second magnetoresistive effect element 16 and the fixed magnetic layer 61 of the first magnetoresistive effect element 15 is fixed by magnetization, When the magnetization fixed direction (P2) of the pinned magnetic layer 61 of the two magnetoresistive effect element 16 is adjusted to a direction 90 degrees different from the magnetization fixed direction (P1) of the first magnetoresistive effect element 15, the first magnetoresistive effect This is to prevent the magnetization fixed direction (P1) of the element 15 from changing. Second, the magnetization directions of the hard bias layers 31 and 36 used in the first magnetoresistive effect element 15 and the second magnetoresistive effect element 16 are supplied to the first magnetoresistive effect element 15 with the same direction. The first bias magnetic field B1 and the second bias magnetic field B2 supplied to the second magnetoresistive effect element 16 are adjusted so as to be different by 90 degrees. If the magnetization directions are not the same, it is difficult to magnetize the hard bias layers 31 and 36 appropriately.

  Therefore, in the present embodiment, first, as described above, the fixed magnetic layer 61 constituting the first element portion 30 and the second element portion 35 has a self-pinning structure. In this embodiment, an antiparallel coupling magnetic field due to the RKKY interaction is generated between the first magnetic layer 61a and the second magnetic layer 61b constituting the fixed magnetic layer 61 by magnetic field treatment, and the magnetization is fixed antiparallel. At this time, heat treatment is not performed as in the prior art. When heat treatment is performed as in the past, even if the magnetization is fixed, the magnetization fixed state collapses due to the heat treatment, but in this embodiment, the self-pinned structure is used so that it is not necessary to perform the heat treatment. The first magnetoresistive effect element 15 and the second magnetoresistive effect element 16 having different magnetization fixed directions (P1, P2) can be appropriately formed on the same sensor chip 11, 12.

  Subsequently, in the present embodiment, as shown in FIG. 2, the first hard bias layer 31 constituting the first magnetoresistive effect element 15 is in the same direction as the magnetization direction (Y1-Y2 direction) with respect to the first element portion 30. The first bias magnetic field B1 can be applied to the second hard bias layer 36 constituting the second magnetoresistive effect element 16 with respect to the second element portion 35 perpendicular to the magnetization direction (Y1-Y2 direction). The second bias magnetic field B2 can be applied from the direction (X1-X2 direction). Therefore, the first hard bias layer 31 and the second hard bias layer 36 have the same magnetization direction (Y1-Y2 direction), and each bias magnetic field B1 supplied to the first element unit 30 and the second element unit 35 is provided. , B2 can be different by 90 degrees.

  As described above, the first magnetoresistance effect element 15 in which the magnetization fixed direction of the fixed magnetic layer 61 (defined by the magnetization direction of the second magnetic layer 61b) that is the sensitivity axis direction is orthogonal to the same sensor chip 11 and 12. The second magnetoresistive element 16 can be formed.

  FIG. 6A to FIG. 6C are process diagrams illustrating a method for manufacturing a magnetic sensor according to this embodiment. Each figure conceptually shows a plan view during the manufacturing process in the same manner as FIG. Note that the XY directions in FIGS. 6A to 6B are rotated by 90 degrees with respect to FIG.

  In FIG. 6A, a substrate 65 is prepared. The substrate 65 has a first region 65 a that becomes the first sensor chip 11 and a second region 65 b that becomes the second sensor chip 12.

  In the step of FIG. 6A, two first magnetoresistive elements 15 are formed in each of the first region 65a and the second region 65b of the substrate 65. Magnetic field treatment is performed to pin the pinned magnetic layer 61 having the laminated ferrimagnetic structure in the X1-X2 direction. P <b> 1 shown in FIG. 6A is the magnetization fixed direction of the second magnetic layer 61 b of the fixed magnetic layer 61 constituting the first magnetoresistive element 15.

  Next, in the process of FIG. 6B, two second magnetoresistive elements 16 are formed in each of the first region 65 a and the second region 65 b of the base material 65. By applying a magnetic field treatment, the pinned magnetic layer 61 having a laminated ferrimagnetic structure is fixed in magnetization in the Y1-Y2 direction orthogonal to the first magnetoresistive element 15. P2 shown in FIG. 6B is the magnetization fixed direction of the second magnetic layer 61b of the fixed magnetic layer 61 constituting the second magnetoresistive effect element 16.

  In this embodiment, since no heat treatment is applied to the magnetization pinning control of each pinned magnetic layer 61, the pinned magnetic layer 61 of the second magnetoresistive element 16 is moved in the Y1-Y2 direction in the step of FIG. Even if a magnetic field is applied to fix the magnetization, the magnetization fixed direction (P1) of the fixed magnetic layer 61 of the first magnetoresistive element 15 already formed in the step of FIG. It can be kept properly in the state of facing.

  Next, in the process of FIG. 6C, the first hard bias layer 31 constituting the first magnetoresistive effect element 15 and the second hard bias layer 36 constituting the second magnetoresistive effect element 16 are arranged in the Y1-Y2 direction. Magnetize at the same time. As a result, the first bias magnetic field B <b> 1 in the Y <b> 1 direction is supplied from the first hard bias layer 31 to the first element portion 30 constituting the first magnetoresistive effect element 15, and the free magnetic layer constituting the first element portion 30. The magnetization direction of 63 is aligned with the Y1 direction. On the other hand, the second bias magnetic field B2 in the X1-X2 direction is supplied from the second hard bias layer 36 to the second element portion 35 constituting the second magnetoresistive effect element 16, and the free magnetism constituting the second element portion 35. The magnetization direction of the layer 63 is aligned with the X1-X2 direction.

  The step of forming the first element part 30 constituting the first magnetoresistive effect element 15 and the second element part 35 constituting the second magnetoresistive effect element 16 into a meander shape as shown in FIG. As long as it is before the formation of the layer 31 and the second hard bias layer 36, there is no particular limitation on the point in time. That is, in FIG. 6A, the first magnetoresistive effect element 15 is formed, and the fixed magnetic layer 61 of the first magnetoresistive effect element 15 is also subjected to a magnetic field treatment to perform magnetization fixed control. After the first element portion 30 constituting the magnetoresistive effect element 15 is left in a solid film state in a certain region and the first element portion 30 is further protected with a resist or the like, the process shown in FIG. The second magnetoresistive effect element 16 is formed, and further, the fixed magnetic layer 61 of the second magnetoresistive effect element 16 is subjected to a magnetic field process to perform magnetization fixed control. The second element portion 35 constituting the second magnetoresistive effect element 16 is also left in a solid film state in a certain region, and then the first element portion 30 and the second element portion 35 are simultaneously formed as shown in FIG. Process into a meander shape. Then, the first hard bias layer 31 constituting the first magnetoresistive effect element 15 and the second hard bias layer 36 constituting the second magnetoresistive effect element 16 are simultaneously formed, and at the same time, the first hard bias layer 36 is simultaneously formed. The layer 31 and the second hard bias layer 36 are magnetized in the same direction.

  Next, in FIG.6 (c), if the board | substrate 65 is cut | disconnected along a BB line, two sensor chips will be completed. Then, one is a first sensor chip 11 and the other is turned over 180 degrees to be a second sensor chip 12 and mounted on a support substrate 9 shown in FIG.

  In the present embodiment, the pinned magnetic layer 61 of the first element portion 30 constituting the first magnetoresistive effect element 15 and the pinned magnetic layer 61 of the second element portion 35 constituting the second magnetoresistive effect element 16 are respectively arranged in the first. The magnetic layer 61a and the second magnetic layer 61b have a laminated ferrimagnetic structure in which the nonmagnetic intermediate layer 61c is laminated, and a self-pinned structure in which no antiferromagnetic layer is used. Further, the first hard bias layer 31 constituting the first magnetoresistive effect element 15 and the second hard bias layer 36 constituting the second magnetoresistive effect element 16 are formed in the shape and each element portion 30 as shown in FIG. , 35, the first bias magnetic field B1 supplied from the first hard bias layer 31 to the first element unit 30 is maintained while keeping the magnetization directions of the hard bias layers 31, 36 in the same direction. The second bias magnetic field B2 supplied from the second hard bias layer 36 to the second element unit 35 is controlled so as to be in a direction orthogonal to the magnetization direction so as to be parallel to the magnetization direction. did.

  This makes it possible to form the first magnetoresistive effect element 15 and the second magnetoresistive effect element 16 whose sensitivity axes are orthogonal to each other on the same sensor chip 11, 12. Therefore, the number of chips can be reduced as compared with the conventional case where only magnetoresistive elements having the same sensitivity axis can be formed on the same chip.

  Therefore, it is possible to reduce misalignment between the magnetoresistive elements 15 and 16 formed on the first sensor chip 11 and the magnetoresistive elements 15 and 16 formed on the second sensor chip 12, The sensor output can be stabilized, for example, a highly accurate linear output (analog output) can be obtained. Further, the manufacturing efficiency can be improved by reducing the number of chips.

  In addition, the circuit configuration having the first bridge circuit 7 and the second bridge circuit 8 shown in FIG. 1B can increase the sensor output and improve the detection accuracy.

  FIG. 7 is an example of a usage pattern of the magnetic sensor 10 in the present embodiment. As shown in FIG. 7A, the magnet 70 faces the magnetic sensor 10 with a gap in the height direction (Z). For example, the magnet 70 has an N-pole facing surface 70a facing the magnetic sensor 10 and an S-pole facing surface 70b. As shown in FIG. 7A, an external magnetic field H acts from the magnet 70 to the magnetic sensor 10.

  FIG. 7B is a diagram in which the plan view of the first sensor chip 11 and the second sensor chip 12 constituting the magnetic sensor 10 and the outer shape of the magnet 70 are overlapped. 7A and 7B show the outputs obtained from the output terminals (VX1, VX2, VY1, VY2) shown in FIG. 1B, with the center O of the magnet 70 positioned at the center of the magnetic sensor 10. FIG. Based on this, it is detected that the center O of the magnet 70 is at the midpoint position of the magnetic sensor 10. For example, if the magnet 70 moves in the X direction, the electric resistance of each of the first magnetoresistive elements 15a to 15d for detecting the X direction changes, whereby each of the output terminals (VX1, VX2) 22, 23 is changed. A differential output calculated from the output value can be obtained. On the other hand, in this embodiment, if the magnet 70 moves in the X direction, the electric resistances of the second magnetoresistive elements 16a to 16d for detecting the Y direction also change, but the output terminals (VY1, VY2) 24. , 25, the differential output calculated from each output value does not change. Therefore, it is possible to detect how much the magnet 70 has moved in the X direction based on the outputs of the X direction detection circuit and the Y direction detection circuit obtained from the circuit of FIG. Naturally, when the magnet 70 moves in the Y direction, the movement direction and the movement amount (relative position) of the magnet 70 can be known even when the magnet 70 moves obliquely between the X direction and the Y direction.

  FIG. 8 shows a magnetic sensor according to the second embodiment. FIG. 8A shows a manufacturing process of the sensor chip constituting the magnetic sensor (same as FIG. 6C), and FIG. 8B shows the substrate 80 from the CC line in FIG. 8A. The top view of the magnetic sensor of the state which has arrange | positioned on the support substrate (not shown) the 1st sensor chip 81 and the 2nd sensor chip 82 which were formed by cut | disconnecting is shown.

  The configuration of each of the first magnetoresistive effect element 15 and the second magnetoresistive effect element 16 shown in FIG. 8 is not different from that shown in FIG. In FIG. 8, two electrode portions 83 are provided for each of the magnetoresistive effect elements 15 and 16. One electrode 83 connected to each of the magnetoresistive elements 15 and 16 is connected to an input terminal or a ground terminal, and the other electrode 83 is connected to an output terminal.

  On the other hand, in FIG. 1A, an electrode portion 18 connected to the input terminal Vdd and the ground terminal GND is provided between the first magnetoresistive effect element 15 and the second magnetoresistive effect element 16 provided in each of the sensor chips 11 and 12. It is common. Therefore, in the magnetic sensor 10 of FIG. 1A, the number of electrodes can be reduced as compared with the magnetic sensor of FIG.

  In the present embodiment, as shown in FIG. 2, the second bias magnetic field B2 in the opposite direction by 180 degrees is supplied from the second hard bias layer 36 to the second element portions 35 located on both sides thereof. It is possible to supply only the second bias magnetic field B2 in one direction to the second element unit 35 by changing the positional relationship between the second hard bias layer 36 and the second element unit 35, or the like.

  In this embodiment, as shown in FIG. 1B, all the elements constituting the bridge circuit are magnetoresistive elements, but some of them may be fixed resistors, for example. In the present embodiment, at least one first magnetoresistive effect element 15 and second magnetoresistive effect element 16 may be formed on the same chip.

  Further, the number of chips arranged on the support substrate 9 is not limited to two. One may be sufficient and three or more may be sufficient. However, at least in this embodiment, the number of chips can be reduced as compared with the conventional case.

B1 first bias magnetic field B2 second bias magnetic field P1, P2 magnetization fixed direction 10 magnetic sensor 11, 81 first sensor chip 12, 82 second sensor chip 15, 15a-15d first magnetoresistive effect element 16, 16a-16d first 2 magnetoresistive effect element 20 input terminal 21 ground terminals 22-25 output terminal 30 first element part 31 first hard bias layer 35 second element parts 36, 36a-36c second hard bias layers 40, 41, 43, 44 61 Pinned magnetic layers 61a and 61b Magnetic layer 61c Nonmagnetic intermediate layer 63 Free magnetic layer 70 Magnet

Claims (7)

A first magnetoresistive element and a second magnetoresistive element are provided on the same sensor chip;
The first magnetoresistive element includes a first element portion in which a free magnetic layer and a pinned magnetic layer are stacked via a nonmagnetic layer, and a first magnetic field for supplying a first bias magnetic field to the first element portion. 1 hard bias layer,
The second magnetoresistive element includes a second element portion in which a free magnetic layer and a pinned magnetic layer are stacked via a nonmagnetic layer, and a second bias magnetic field for supplying the second element portion to the second element portion. A second hard bias layer,
In each pinned magnetic layer of the first element portion and the second element portion, a first magnetic layer and a second magnetic layer are laminated via a nonmagnetic intermediate layer, and the first magnetic layer and the second magnetic layer Is a self-pinned structure in which magnetization is fixed in antiparallel, and the magnetization fixed direction of the second magnetic layer that is the sensitivity axis direction is orthogonal between the first element part and the second element part,
The first hard bias layer and the second hard bias layer have the same magnetization direction, and the first bias magnetic field extends from the first hard bias layer to the first element portion in a direction parallel to the magnetization direction. And a second bias magnetic field is supplied from the second hard bias layer to the second element portion from a direction orthogonal to the magnetization direction. In the first magnetoresistive effect element, the first direction is the sensitivity axis direction, and in the second magnetoresistive effect element, the second direction orthogonal to the first direction is the sensitivity axis direction,
The second direction is a magnetization direction for each hard bias layer, the first element portion is supplied with the first bias magnetic field from the second direction, and the second element portion has the first direction. The magnetic sensor according to claim 1, wherein the second bias magnetic field is supplied from a direction.   3. The magnetic sensor according to claim 2, wherein a surface of the second hard bias layer facing the second element portion is inclined obliquely from the second direction toward the first direction in plan view.   The first sensor chip and the second sensor chip are provided, and the first magnetoresistive effect element and the second magnetoresistive effect element are formed in each sensor chip. The magnetic sensor described.   The magnetic sensor according to claim 4, wherein the second sensor chip is configured by rotating the first sensor chip by 180 degrees.   A substrate on which the first magnetoresistive element and the second magnetoresistive element are respectively formed in a plurality of regions is cut between the regions to form the first sensor chip and the second sensor chip. The magnetic sensor according to claim 4 or 5. Each sensor chip is provided with two each of the first magnetoresistance effect element and the second magnetoresistance effect element,
An external magnetic field in the first direction is generated by the two first magnetoresistive elements provided in the first sensor chip and the two first magnetoresistive elements provided in the second sensor chip. A detectable first bridge circuit is configured,
The two second magnetoresistive elements provided in the first sensor chip and the two second magnetoresistive elements provided in the second sensor chip are orthogonal to the first direction. The magnetic sensor according to any one of claims 4 to 6, wherein a second bridge circuit capable of detecting an external magnetic field in the second direction is configured.

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